Database linked to precision medicine in general and their links [30].
\r\n\t
",isbn:"978-1-83969-600-8",printIsbn:"978-1-83969-599-5",pdfIsbn:"978-1-83969-601-5",doi:null,price:0,priceEur:0,priceUsd:0,slug:null,numberOfPages:0,isOpenForSubmission:!0,hash:"47659401ffe512c28313440110c0a903",bookSignature:"Dr. Min Huang",publishedDate:null,coverURL:"https://cdn.intechopen.com/books/images_new/10896.jpg",keywords:"Yield Potential, Grain Quality, Biotic Stress Resistance, Climatic Adaptation, Soil Management, Straw Management, Mechanical Transplanting, Direct Seeding, Nutrient Management, Water Management, Pest Management, Abiotic Stress Management",numberOfDownloads:null,numberOfWosCitations:0,numberOfCrossrefCitations:null,numberOfDimensionsCitations:null,numberOfTotalCitations:null,isAvailableForWebshopOrdering:!0,dateEndFirstStepPublish:"February 26th 2021",dateEndSecondStepPublish:"March 26th 2021",dateEndThirdStepPublish:"May 25th 2021",dateEndFourthStepPublish:"August 13th 2021",dateEndFifthStepPublish:"October 12th 2021",remainingDaysToSecondStep:"21 days",secondStepPassed:!1,currentStepOfPublishingProcess:2,editedByType:null,kuFlag:!1,biosketch:"Dr. Huang is a professor in crop science at the Hunan Agricultural University, a committee member of the Council of the International Forum on Rice Development, and a first and/or corresponding author of more than 70 publications in international journals.",coeditorOneBiosketch:null,coeditorTwoBiosketch:null,coeditorThreeBiosketch:null,coeditorFourBiosketch:null,coeditorFiveBiosketch:null,editors:[{id:"189829",title:"Dr.",name:"Min",middleName:null,surname:"Huang",slug:"min-huang",fullName:"Min Huang",profilePictureURL:"https://mts.intechopen.com/storage/users/189829/images/system/189829.jpg",biography:"Dr. Min Huang received his PhD in the major of Crop Cultivation and Farming System from the Hunan Agricultural University (HAU), China in 2011. He successively held the positions of Assistant and Associate Professor in the Department of Agronomy at the Guangxi University, China from 2012 to 2014. He joined the faculty as an Associate Professor in the Department of Agronomy at the HAU in 2015 and was promoted to the position of Professor in 2017. He worked as a visiting fellow at the International Programs-College of Agriculture and Life Sciences, Cornell University, USA in 2017 and 2018. He serves as a committee member of the Crop Cultivation Professional Council of the Crop Science Society of China and a committee member of the Council of the International Forum on Rice Development. He obtained 5 research grants from the National Natural Science Foundation of China and the Ministry of Science and Technology of China. He is a first and/or corresponding author of more than 70 publications in international journals and an editor of 2 books. He won the Excellent Doctoral Thesis Award of Hunan Province in 2014, and the Second Prize of Science and Technology Progress Award of the Ministry of Education of China in 2016.",institutionString:"Hunan Agricultural University",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"1",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"Hunan Agricultural University",institutionURL:null,country:{name:"China"}}}],coeditorOne:null,coeditorTwo:null,coeditorThree:null,coeditorFour:null,coeditorFive:null,topics:[{id:"5",title:"Agricultural and Biological Sciences",slug:"agricultural-and-biological-sciences"}],chapters:null,productType:{id:"1",title:"Edited Volume",chapterContentType:"chapter",authoredCaption:"Edited by"},personalPublishingAssistant:{id:"301331",firstName:"Mia",lastName:"Vulovic",middleName:null,title:"Mrs.",imageUrl:"https://mts.intechopen.com/storage/users/301331/images/8498_n.jpg",email:"mia.v@intechopen.com",biography:"As an Author Service Manager, my responsibilities include monitoring and facilitating all publishing activities for authors and editors. From chapter submission and review to approval and revision, copyediting and design, until final publication, I work closely with authors and editors to ensure a simple and easy publishing process. I maintain constant and effective communication with authors, editors and reviewers, which allows for a level of personal support that enables contributors to fully commit and concentrate on the chapters they are writing, editing, or reviewing. I assist authors in the preparation of their full chapter submissions and track important deadlines and ensure they are met. I help to coordinate internal processes such as linguistic review, and monitor the technical aspects of the process. As an ASM I am also involved in the acquisition of editors. Whether that be identifying an exceptional author and proposing an editorship collaboration, or contacting researchers who would like the opportunity to work with IntechOpen, I establish and help manage author and editor acquisition and contact."}},relatedBooks:[{type:"book",id:"6418",title:"Hyperspectral Imaging in Agriculture, Food and Environment",subtitle:null,isOpenForSubmission:!1,hash:"9005c36534a5dc065577a011aea13d4d",slug:"hyperspectral-imaging-in-agriculture-food-and-environment",bookSignature:"Alejandro Isabel Luna Maldonado, Humberto Rodríguez Fuentes and Juan Antonio Vidales Contreras",coverURL:"https://cdn.intechopen.com/books/images_new/6418.jpg",editedByType:"Edited by",editors:[{id:"105774",title:"Prof.",name:"Alejandro Isabel",surname:"Luna Maldonado",slug:"alejandro-isabel-luna-maldonado",fullName:"Alejandro Isabel Luna Maldonado"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"1591",title:"Infrared Spectroscopy",subtitle:"Materials Science, Engineering and Technology",isOpenForSubmission:!1,hash:"99b4b7b71a8caeb693ed762b40b017f4",slug:"infrared-spectroscopy-materials-science-engineering-and-technology",bookSignature:"Theophile Theophanides",coverURL:"https://cdn.intechopen.com/books/images_new/1591.jpg",editedByType:"Edited by",editors:[{id:"37194",title:"Dr.",name:"Theophanides",surname:"Theophile",slug:"theophanides-theophile",fullName:"Theophanides Theophile"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"3092",title:"Anopheles mosquitoes",subtitle:"New insights into malaria vectors",isOpenForSubmission:!1,hash:"c9e622485316d5e296288bf24d2b0d64",slug:"anopheles-mosquitoes-new-insights-into-malaria-vectors",bookSignature:"Sylvie Manguin",coverURL:"https://cdn.intechopen.com/books/images_new/3092.jpg",editedByType:"Edited by",editors:[{id:"50017",title:"Prof.",name:"Sylvie",surname:"Manguin",slug:"sylvie-manguin",fullName:"Sylvie Manguin"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"3161",title:"Frontiers in Guided Wave Optics and Optoelectronics",subtitle:null,isOpenForSubmission:!1,hash:"deb44e9c99f82bbce1083abea743146c",slug:"frontiers-in-guided-wave-optics-and-optoelectronics",bookSignature:"Bishnu Pal",coverURL:"https://cdn.intechopen.com/books/images_new/3161.jpg",editedByType:"Edited by",editors:[{id:"4782",title:"Prof.",name:"Bishnu",surname:"Pal",slug:"bishnu-pal",fullName:"Bishnu Pal"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"72",title:"Ionic Liquids",subtitle:"Theory, Properties, New Approaches",isOpenForSubmission:!1,hash:"d94ffa3cfa10505e3b1d676d46fcd3f5",slug:"ionic-liquids-theory-properties-new-approaches",bookSignature:"Alexander Kokorin",coverURL:"https://cdn.intechopen.com/books/images_new/72.jpg",editedByType:"Edited by",editors:[{id:"19816",title:"Prof.",name:"Alexander",surname:"Kokorin",slug:"alexander-kokorin",fullName:"Alexander Kokorin"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"1373",title:"Ionic Liquids",subtitle:"Applications and Perspectives",isOpenForSubmission:!1,hash:"5e9ae5ae9167cde4b344e499a792c41c",slug:"ionic-liquids-applications-and-perspectives",bookSignature:"Alexander Kokorin",coverURL:"https://cdn.intechopen.com/books/images_new/1373.jpg",editedByType:"Edited by",editors:[{id:"19816",title:"Prof.",name:"Alexander",surname:"Kokorin",slug:"alexander-kokorin",fullName:"Alexander Kokorin"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"57",title:"Physics and Applications of Graphene",subtitle:"Experiments",isOpenForSubmission:!1,hash:"0e6622a71cf4f02f45bfdd5691e1189a",slug:"physics-and-applications-of-graphene-experiments",bookSignature:"Sergey Mikhailov",coverURL:"https://cdn.intechopen.com/books/images_new/57.jpg",editedByType:"Edited by",editors:[{id:"16042",title:"Dr.",name:"Sergey",surname:"Mikhailov",slug:"sergey-mikhailov",fullName:"Sergey Mikhailov"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"371",title:"Abiotic Stress in Plants",subtitle:"Mechanisms and Adaptations",isOpenForSubmission:!1,hash:"588466f487e307619849d72389178a74",slug:"abiotic-stress-in-plants-mechanisms-and-adaptations",bookSignature:"Arun Shanker and B. Venkateswarlu",coverURL:"https://cdn.intechopen.com/books/images_new/371.jpg",editedByType:"Edited by",editors:[{id:"58592",title:"Dr.",name:"Arun",surname:"Shanker",slug:"arun-shanker",fullName:"Arun Shanker"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"878",title:"Phytochemicals",subtitle:"A Global Perspective of Their Role in Nutrition and Health",isOpenForSubmission:!1,hash:"ec77671f63975ef2d16192897deb6835",slug:"phytochemicals-a-global-perspective-of-their-role-in-nutrition-and-health",bookSignature:"Venketeshwer Rao",coverURL:"https://cdn.intechopen.com/books/images_new/878.jpg",editedByType:"Edited by",editors:[{id:"82663",title:"Dr.",name:"Venketeshwer",surname:"Rao",slug:"venketeshwer-rao",fullName:"Venketeshwer Rao"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"4816",title:"Face Recognition",subtitle:null,isOpenForSubmission:!1,hash:"146063b5359146b7718ea86bad47c8eb",slug:"face_recognition",bookSignature:"Kresimir Delac and Mislav Grgic",coverURL:"https://cdn.intechopen.com/books/images_new/4816.jpg",editedByType:"Edited by",editors:[{id:"528",title:"Dr.",name:"Kresimir",surname:"Delac",slug:"kresimir-delac",fullName:"Kresimir Delac"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}]},chapter:{item:{type:"chapter",id:"19273",title:"Embryonic Stem Cells and the Germ Cell Lineage",doi:"10.5772/25116",slug:"embryonic-stem-cells-and-the-germ-cell-lineage",body:'Stem cells possess the unique ability to either propagate by self-renewal or to differentiate to mature tissues under the influence of appropriate molecular cues. This remarkable feature, also termed “stem cell potency” has been the focus of both a historical and current research spotlight on stem cells, and particularly the potential for human stem cells in regenerative medicine and organ transplantation. There are several classes of stem cells, all varying in degrees of pluripotency. Depending on the developmental stage from where they originate, stem cell potencies range from totipotency (ability to transform into all cell types), pluripotency (most cell types), multipotency (many cell types), oligopotency (few cell types) to unipotency (one cell type) (Smith, 2001). Among these, embryonic stem cells (ESCs) represent the prototypical pluripotent stem cells.
Embryonic stem cells are localized to the inner cell mass of the developing mammalian blastocyst and can give rise to all future cell types and tissues of the organism. Additionally, a small population of embryonic stem cells is allocated to the germline (primordial germ cells). The evolution of these germline stem cells is different from the remaining cells which undergo gastrulation and give rise to the three germ layers (endoderm, mesoderm and ectoderm) during development (Ewen & Koopman, 2010). The survival, gonadal migration and proper epigenetic programming of primordial germ cells (PGCs) are major, distinct and early events that have an impact on future fertility and the successful transmission of genetic information from parent to offspring.
Finally, stem cells found in neonatal tissues, amniotic fluid, cord blood, and adult tissues are categorized as adult stem cells and are usually multipotent, oligopotent or unipotent. Adult stem cells are clinically important due to the absence of ethical and federal restrictions on their use. Furthermore, they are valued for their relative abundance and accessibility in somatic tissues. In contrast, human embryonic stem cells have been the focus of substantial research and discussion because of their unique potential to differentiate into almost all body cell types and tissues and the relative ease with which they are propagated in cell culture. The search for an alternative source of pluripotent stem cells other than from human embryos is a much sought after goal in the stem cell research community for several reasons. First, diversity in stem cells sources should be explored to better understand and evaluate their various clinical utilities. Second, immunological matching of stem cells to recipients is necessary to avoid rejection in stem cell-based regenerative therapies. Hence, the advent of induced pluripotency and nuclear reprogramming strategies have been well received as alternatives to derive human stem cells (Yamanaka & Blau, 2010). Finally, the derivation and use of stem cells require adherence to moral, ethical and political guidelines that are constantly changing. This chapter will review the formation of the human germline from embryonic stem cells and the subsequent derivation of gametes from mouse and human pluripotent stem cells, with an emphasis on the male germline.
The first forays into understanding pluripotency in the mammalian embryo began with rather simple experiments in which pieces of mouse germ cell tumors known as teratocarcinomas were grown in culture and a variety of pluripotent cell types emerged (Solder, 2006). One cell type, termed Embryonal Carcinoma Cells (ECCs), produced all three germ layers as well as the original tumorigenic cells when isolated and transplanted into host mice. This established for the first time the pluripotent nature of embryonic cells. In the mouse pre-implantation embryo, embryonic stem cells (mESCs) first form within the inner cell mass (ICM). In studies by Evans and Kauffman and others, cells of the ICM were isolated from late blastocysts and grown in culture (Evans & Kaufman, 1981; Martin, 1981). These cells proliferated and demonstrated the capacity of self-renewal. The subsequent addition of Leukemia Inhibitory Factor (LIF) promoted the self-renewal of mESCs in culture by acting through the Stat3 pathway (Ying et al., 2008). Further studies showed that the ICM-derived cells could, if reintroduced into an embryo lacking an ICM, recolonize and form all three germ layers of the embryo, including the germline (Bradley et al., 1984). MESCs are characterized by the strong and persistent expression of important pluripotency genes such as Oct4, Sox2, Nanog and Tcf, among others. Thus, in mice, the pluripotent nature of cells derived from the inner cells mass was established relatively rapidly and easily than in the human.
In the human, embryonic stem cells (hESCs) are derived in a very similar manner to mouse ESCs from explants of the Inner Cell Mass (ICM) of in vitro fertilized blastocysts. Thomson et al. first isolated hESCs from pre-implantation human blastocysts and analyzed their morphology and expression of pluripotency genes (Thomson et al., 1998). Although they express high levels of pluripotency genes, hESCs share a morphology that is more consistent with that of early epiblast stem cells of the mouse (mEpiSCs). Specifically, they are “flattened.“ In addition, they depend on basic FGF and Activin signaling for self-renewal, possess large nuclear to cytoplasmic ratios, and respond less favorably to single cell clonability in contrast to mESCs (Vallier et al., 2005, 2009). While the TGFβ/Activin/Nodal signaling pathways are undoubtedly important for hESC pluripotency, the molecular mechanisms underlying these observations have yet to be explained. Meanwhile, the transcription factors Oct4, Nanog and Sox2 are clearly all involved in hESC pluripotency and newer molecules such as the WNTs (Wingless-Type MMTV Integration Site Family Members) have been implicated to drive hESC self-renewal through canonical signaling pathways (Sato et al., 2004). The functions of Oct4, Sox2 and Nanog are regarded as indispensable for hESC self-renewal as their expression typically reduces when hESCs differentiate. Finally, hESCs and mESCs are similar in that they both express a reportoire of cell surface proteins that distinguish them from other cell types, including SSEA-3, SSEA-4, Tra1-60 and Tra1-81, markers that are routinely used for characterization of ES and iPS cell lines.
Despite the fact that mESCs and hESCs are derived from seemingly equivalent epiblast cells in the blastocyst, there remains the question of whether hESCs possess as ‘naïve’ a state of pluripotency as do mESCs. This is because mESCs in culture behave more like the early mouse epiblast and demonstrate unrestricted potential for differentiation (Hanna & Jaenisch, 2010). Meanwhile, hESCs share some properties with mouse epiblast stem cells (pluripotency) but may be more restricted than mESCs (Vallier & Pedersen, 2009). This may be the case because current hESC derivation methods from ICM could actually select for cells in a different developmental stage than that from the mouse ICM (Nichols & Smith, 2011). Additionally, it has been observed that ESCS and embryonic germ cells (EGCs) share several biomarkers making it difficult to distinguish between the embryonic, pluripotent cells and primitive germ cells. The intimate relationship that exists between germline and embryonic stem cells in mice and humans is critically important to understand in the future, and will vastly improve current and future efforts to derive ‘artificial’ gametes.
A set of landmark studies conducted by Yamanaka and others recently revealed that just four factors normally produced in the embryo are sufficient to reprogram differentiated, non-embryonic cells into pluripotent stem cells. This important finding bypasses many of the ethical issues associated with the use of human embryos, and also evades potential problems with immune rejection that might affect patients upon stem cells transplantation. The four Yamanaka reprogramming factors, Oct4, Sox2, Klf4 and c-Myc, when introduced into differentiated cells in excess amounts, reverses cell fate and by inducing these cells to revert back to a progenitor-like or ESC-like state. It is believed that this is a stochastic process whose mechanisms lie in the ability of these four transcription factors to induce epigenetic restructuring of the genome, thereby enabling expression of previously silenced genes (Hanna & Jaenisch, 2010). These artificially created pluripotent stem cells are termed induced pluripotent stem cells (iPSCs) and were first described by Takashaki and Yamanaka in rats in 2006 (Takahashi & Yamanaka, 2006). The same researchers also demonstrated that they could derive iPSCs from adult human cells, a finding subsequently confirmed by others (Nakagawa et al., 2008; Park et al., 2008; Takahashi et al., 2007; Yu et al., 2007).
A major concern with iPS cells is the level of genomic disruption that occurs with viral delivery of the reprogramming factors using retroviral or lentiviral vectors. Theoretically, these viral vectors, by integrating randomly into the host genome, may cause chromosomal translocations or transform reprogrammed cells into malignant cells. There are now several initiatives underway that seek to understand the degree of genome-wide mutations and changes in gene function that occur in iPSCs (Panopoulos et al., 2011). The art of generating pluripotent cells now involves making iPSCs with reprogramming proteins using techniques that both avoid the use of embryos and the downstream hazards of viral vectors. Additionally, it is now possible to employ just the reprogramming proteins of these factors without the use of viral vectors to create iPSCs (Zhou et al., 2009). Several gene delivery systems that have been described include employing excisable polycistronic cassettes (Sommer et al., 2010; Somers et al., 2010), piggyBAC introduction (Yusa et al., 2009), transfection and/or nucleofection of plasmids (Okita et al., 2008) and most recently, mRNA and miRNA delivery (Warren et al., 2010). There is also evidence that small chemicals can be used as agents to induce reprogramming in somatic cells (Zhu et al., 2010). Finally, direct reprogramming methods wherein cells from one lineage are directly trans-differentiated to another lineage (e.g. fibroblast to neural-like lineage) are gaining in popularity. Specifically, terminally differentiated cells like skin fibroblasts can be exposed to a cocktail of factors that simultaneously enable reversal of cell fate and induce differentiation to the second lineage (Ieda et al., 2009; Uhlenhaut et al., 2009; Vierbuchen et al., 2010). The use of human, patient-specific iPSCs in regenerative medicine represents an exciting clinical avenue for the future, and will likely find application to human germ cell development.
Among of the many ethical, technical, and safety concerns associated with the clinical application of stem cells, the primary concern surrounds the stem cell source. Human embryonic stem cells have generated the most controversy because the procedure of deriving a hESC line involves the sacrifice of a donated human embryo, even though the donated embryos most likely will be discarded (reviewed in Greely, 2006; Scott & Reijo Pera, 2008). Therefore, alternative sources of stem cells, such as iPSCs, which might achieve similar therapeutic goals, could be very valuable and bear fewer ethical issues than embryonic stem cells. Since one of the standard measures of a pluripotent stem cell is that it reliably forms teratomas when transplanted into animal models, careful long-term analysis and follow-up after transplantation will be needed in animal models before stem cells or directed differentiated cells are applied to humans. Yet, hESCs still represent the best model system with which to study early human development because of their differentiation potential and epigenetic programming and therefore remain the standard for studying stem cells properties. However, their suitability for transplantation studies is questionable mainly because of the risk of immune rejection from host human tissues (Swijnenburg et al., 2008). In contrast, patient-autologous iPSCs are considered more suitable for clinical transplantation due to better immunological suitability, but their differentiation profiles, epigenetic status, and potential for tumor formation are far less well characterized than are hESCs (Hyun et al., 2007). Therefore, it is imperative that studies with hESCs continue to allow better definition of the true potential of all other stem cell sources, including human iPSCs. Fortunately, there is currently considerable research devoted to deciphering the molecular mechanisms that underlie the cell fate reprogramming process. In parallel, many laboratories are now developing iPSC-based disease models for human degenerative diseases and cancers. These in vitro studies should provide the research community with insight into the mechanisms of disease progression and illuminate avenues of therapeutic potential. Consequently, hESCs will likely remain the “gold standard” stem cell type for developing basic scientific and clinical therapeutic protocols, and to which iPSCs and adult stem cells will be carefully compared for their therapeutic potential.
The establishment of early germ cells and their successful maturation are complex processes, and require frequent changes in physiology, location and transcriptional profile of involved cells. Germline establishment in mammals occurs via “inductive” signaling, in contrast to lower organisms such as flies and worms where the germ cell identity is transmitted via the inheritance of germ “plasm” (McLaren, 1999, 2000; Saitou et al., 2002). In rodents and humans, the first glimpses of primordial germ cell (PGC) formation are observed in the embryo after implantation and gastrulation, when the epiblast, endoderm, mesoderm and ectoderm are first established (Matsui & Okamura, 2005). At this time, in response to molecular cues including Bone Morphogenetic Proteins (BMP4 and BMP8a) from the yolk sac, a population of pluripotent stem cells is segregated from the ICM and set physically apart from the extra-embryonic ectoderm or yolk sac of the embryo (Figure 1) (Lawson et al., 1999; Ying 2000, 2001). While BMPs provide the inductive signal to epiblast stem cells to supply PGCs, it is not clear what signals control the size of the PGC founder population or what molecules signal the termination of PGC specification. BMPs are crucial to specification of PGCs due to their activation of the ALK2 receptor and Smad-1/5 signaling pathways, as evidenced in mice (Hayashi et al., 2002). In the human embryo, the effects of BMPs on germline specification are unclear because there is very limited access to early embryonic samples. From work in our laboratory, it appears that similar BMP protein pathways are activated in the human embryo during gastrulation that direct PGC specification (Clark & Reijo Pera, 2006, Kee et al, 2006).
Additional mechanisms that may assist germline specification are the activation of pathways that either promote PGC survival and/or inhibit molecules that promote somatic differentiation of PGCs (Ewen & Koopman, 2010). As such, mouse and human PGCs retain expression of several biomarkers of pluripotency, including Oct4, Nanog and Sox2 which underlies their close resemblance to other pluripotent stem cells (Clark & Reijo Pera, 2006; Medrano et al., 2010; Nicholas et al., 2009). Interestingly, the transcription factor Sox2 is expressed on both mouse and human embryonic stem cells but unlike in the mouse, human Sox2 expression is diminished when PGCs migrate to the fetal gonad (Perrett et al., 2008). Coincident with the timing of germline specification in the mouse (E7.5), PGCs near the extraembryonic ectoderm begin to express germ-cell specific markers such as Blimp-1 (Prdm1 in human), Stella (Dppa3 in human), E-Cadherin, and Dazl and harbor alkaline phosphatase activity. Blimp-1/Prdm-1 is a transcriptional repressor whose activity is restricted to the germ lineage and appears to be critical for maintaining a PGC fate. There is strong evidence to suggest that in the mouse, Blimp-1 actively represses the somatic fate of PGCs by inhibiting expression of key somatic regulators during development (Ohinata et al., 2005; Hayashi et al., 2007). It is unclear whether Prdm-1 carries out a similar function in human germline formation. Once cell-cell communication has been established, the Fragilis (IFITIM-1 in human) and Stella/ Dppa3 genes promote further development of PGCs and may do so in a similar fashion as Blimp-1 in mice (Saitou et al., 2002).
Migration of germ cells to the gonad begins at E8.5 in the mouse and during weeks 4 to 6 of human gestation (first trimester). At this stage, PGCs accumulating at the base of the allantois exit the extraembryonic ectoderm and begin migration to the developing gonads, also known as the genital ridge. During migration, PGCs also proliferate by undergoing mitosis and express a new set of biomarkers, including the CXCR4 receptor in mice and the proto-oncogene c-KIT and its ligand, KIT in both mice and humans (Molyneaux & Wylie, 2004; Gomperts et al., 1994). The DAZ gene homologue, DAZL is also expressed on migrating PGCs. In the mouse, migratory PGCs display pseudopodia that may assist in movement through the hindgut and it is plausible that human germ cells behave similarly since they are also observed in the hindgut during migration. Various somatic tissues interact with PGCs during the migratory path to the gonad. It is likely therefore, that these tissues express molecules and factors that guide or “cue” the PGCs and help maintain their survival. In the mouse, several candidate molecules have been identified, including receptors such as β-1 Integrin and extracellular matrix components such as Collagen I (Chuva de Sousa Lopes et al., 2005; De Felici et al., 2005). Although migration of PGCs is less well understood in human development, germ cells have been histologically observed during the late first trimester, when they undergo migration to the hindgut (Fujimoto et al., 1977; Gaskell et al., 2004; Goto et al., 2004). Male and female PGCs have been isolated from
Developmental Cycle of Mammalian Germ Cells. Life cycle of the mouse and human embryo following fertilization, progressing through gastrulation and producing the germline. The germline develops in the gonads and transmits genetic information to the next generation, thus completing the cycle. Fertilization of oocytes by sperm promotes the formation of a 1-cell zygote that undergoes cell division and cleavage to form a blastocyst. The outer layer of blastocyst gives rise to the trophectoderm while the inner cell mass (ICM) contains embryonic stem cells (ESCs). During gastrulation (E7.5 in mouse; Day 15+ in human), the blastocyst cavitates and develops the three germ layers and the epiblast. The primordial germ cells (PGCs) are specified and localize near the extra-embryonic ectoderm, at the base of the allantois. Once PGCs are specified, they migrate to the fetal gonads and undergo sex-specific developmental to male and female gonocytes. Subsequently, male gonocytes undergo spermatogenesis while female gonocytes enter meiotic prophase I and begin oogenesis. Adapted from Schuh-Huerta et al., 2011.
10-week old fetuses and were observed to express Alkaline Phosphatase (AP), a marker of PGCs (Goto et al., 2004). The morphology of human PGCs also resemble the rounded shape of mouse PGCs. Female-specific germ cells have also been visualized at the ultrastructural level during gonadal development in human fetuses (Motta et al., 1997). Finally, recent studies by Kerr et al. with human fetal gonads (testis and ovary) provide a detailed analysis of pluripotency and germ cell-specific markers. The germ cells of the fetal testis are Oct4 +/Nanog +/ c-Kit+ from week 7 to 15 after which these cells become localized to the testis periphery. Meanwhile, the presumptive gonocytes in the week 15 testis show strong expression of Pumilio2 (PUM2), VASA and DAZL and express low to no pluripotency markers (Oct4, Nanog, c-Kit, Tra1-60, Tra1-81) (Kerr et al., 2007). In the human fetal ovary, as in the testis, the expression of pluripotency markers peaks by week 8 and then declines after week 9, as oocytes enter meiosis (Kerr et al., 2008). Interestingly, the cell surface markers SSEA-1 and SSEA-4 are co-expressed on the female germ cells from week 5 onwards although only SSEA-1 is restricted to the germ cell lineage.
Upon arrival at the genital ridge, germ cells express another germ-cell specific marker, VASA, a cytoplasmic protein that is implicated in translational regulation. The gene encoding VASA expression, DDX4 (Mvh in mouse) is highly conserved among species and is expressed exclusively in both male and female pre-meiotic germ cells (Gustafson & Wessel, 2010). This finding underlines the importance of the VASA protein in germline function and makes it an attractive candidate for further study. Along with VASA, other factors produced are germ cell nuclear antigen-1 (GCNA-1) and E-cadherin. The sex-specific character of the developing gonad is controlled by the chromosomal constitution of gonadal somatic cells. In particular, the SRY gene expressed on the Y chromosome in mammals is thought to be an essential regulator of various downstream targets including the Sox9 gene that controls male gonadal development (McLaren, 1995, 2003). Once within the gonad, germ cells associate with Sertoli cells to form testis cords and this interaction induces the expression of VASA in post-migratory PGCs. VASA expression is induced in both male and female PGCs and persists until these cells enter meiosis and after which its levels diminish (Castrillon et al., 2000; Toyooka et al., 2000).
During germline development, an extensive remodeling of the epigenetic landscape occurs. This takes place during embryogenesis and during PGC migration to the gonad (Nicholas et al, 2009). The first wave of epigenetic remodeling occurs during implantation of the blastocyst and involves the erasure of all DNA methylation at CpG islands except those at imprinted gene loci. This transition is observed in all cells of the embryo, including the primitive germline. In female PGCs, there is another level of epigenetic change in the form of random X inactivation wherein one copy of the X chromosome pair is silenced. The second wave of epigenetic remodeling occurs when PGCs migrate to the primitive gonads and their paternal or maternal imprinted loci undergo a gradual process of erasure (Hajkova et al., 2002; Yamazaki et al., 2003). This phase occurs only in germ cells and may help to prime them for sex-specific DNA remethylation, when their developmental programs are established (Durcova-Hills et al., 2006). In the mouse, the re-establishment of imprints takes place prior to birth in the male prospermatogonia (E15) and only after birth in oocytes (Lucifero et al., 2002). In addition to DNA methylation changes, male and female germ cells also undergo post-translational histone modifications and RNA-mediated silencing (Reviewed in Tasler, 2009 & Nicolas et al., 2009).
The successful passage of germ cells through meiosis is a unique and highly rigorous process. However, between male and female embryos, the timing of meiosis is different. Male germ cells are restricted from entering meiosis while female germ cells enter meiosis within the embryo. Although the mechanisms for these contrasting behaviors are unclear, it appears that the gonadal cells provide the signal for (or against) meiotic entry (Brennan & Capel, 2004; Ewen & Koopman, 2010). One signal could be retinoic acid (RA) produced in the fetal ovary, which in turn induces Stra8, a key regulator of meiotic entry. In female germ cells destined to become oocytes, mitotic divisions cease and meiotic prophase begins with the correct stimuli (Borum, 1961); eventually oocytes arrest during Meiosis I prior to fetal birth and will only resume meiosis upon receiving hormonal signals during adulthood (Peters, 1970). Meanwhile, male germ cells transition from primordial status to the gonocyte stage, stop proliferating and remain quiescent in the fetal seminiferous tubules until after birth. The post-natal gonocytes then commit to a spermatogonial stem cell (SSC) fate and amplify through self-renewal or enter meiosis to initiate spermatogenesis. In both male and female germ cells, the synaptonemal complex proteins (SCPs) SCP-1, SCP-2 and SCP-3 are critical components of the meiotic machinery during chromosomal segregation (Chuma et al., 2001; Parra et al., 2004; Yuan et al., 2000). The completion of meiosis signals that germ cells have matured into haploid male and female gametes. At this stage, oocytes exclusively express GDF9 and spermatocytes express TEKT1. However, one feature that distinguishes human and mouse germline differentiation is the synchronization of meiotic entry, as in human fetal gonads, one can observe both pre-meiotic and meiotic germ cells in close proximity (Anderson, 2007).
Significant efforts have been made to culture mouse and human PGCs and gonocyes in vitro. In the case of mouse germ cells, the addition of endogenous factors known to affect germ cell development such as BMPs, RA, LIF and Forskolin have produced mixed results in maintaining PGCs in culture. For example, adding LIF enhanced PGC survival but the observations with the use of other factors not as clear. PGCs may also behave erratically in culture (showing low survival rates and non sex-specific behavior) because of the lack of a normal somatic environment (Childs et al., 2008). Studies of PGCs by Shamblott et al., Turnpenny et al. and Tu et al. with fetal human gonocytes resulted in a mixture of cellular phenotypes. Some gonocytes appeared rounded while others took on an elongated or ‘spindly’ appearance. In addition, they appeared to have different proliferation rates (Shamblott et al., 1998; Turnpenny et al., 2003; Tu et al., 2007). Currently, it is not at all clear that these cells resemble their germ cell counterparts in vivo, but improvements in culture conditions and the cellular microenvironment will certainly help in this regard.
As delineated earlier, mammalian germ cells populate the testis and ovary during development in a incredibly dynamic manner. During early prenatal mice and human embryo development, PGCs migrate to the primitive gonad (gonadal ridge) and associate with Sertoli cells to form primitive testicular cords (Brennan et al., 2004). Within the testicular cords, the primitive germline stem cells (now termed gonocytes) remain in the testis as the gonad differentiates. Eventually, Sertoli cells, peritubular myoid cells and gonocytes form more compact structures known as the seminiferous tubules. When the gonocytes migrate to the periphery of the tubules, they transform into prospermatogonia and then into spermatogonia (Gondos & Hobel, 1971). In the fetal testis, prospermatogonia enter mitotic arrest, a feature observed at E12.5 to E14.5 in the mouse. At the molecular level, during entry into meiosis, both male and female human gonocytes express DAZL proteins and Vasa transcripts and downregulate OCT3/4 expression (Anderson et al., 2007). Interestingly, it is the early migrating germ cells that share similar properties with embryonic stem cells and testicular germ cell tumors (Ezeh et al., 2005). From what is known, the development of gonocytes in the fetal ovary follows a similar path in that OCT3/4 expression is reduced while VASA, Germ Cell Nuclear Antigen (GCNA) and DAZL are expressed (McLaren, 2003). In contrast to the male gonocytes, the female gonocytes receive sex-specific signals from the fetal gonad to enter meiotic prophase. After initiating meiosis, the female gonocytes will develop into primordial follicles and subsequently into primary follicles at puberty. A key difference between mouse and human systems is the timing of primary follicle formation: the mouse achieves this stage at birth while in the human ovary, this occurs at puberty (Bukovsky et al., 2005). There is some speculation whether this difference in follicle development is due to autocrine signals produced from the oocyte itself or from the ovarian environment (Hutt & Albertini, 2007). A plausible hypothesis is that the immediate environment of early germ cells determines whether they are commit to spermatogenesis or oogenesis. The most obvious source of signals are the mesonephros, primitive Sertoli cells in the testis, and primitive Granulosa cells in the ovary.
Timeline of Germline Specification and Germ Cell Marker Expression. A temporal representation of the stages of human and mouse germline differentiation in vivo. At each cellular stage, important molecular and somatic signals controlling that stage are indicated above the diagram. Specific germ cell molecular markers are indicated on left with arrows depicting the duration of development during which they expression has been observed. Genes that are italicized are present in both mouse and human germ cells. At the bottom, an approximate timing of each stage during mouse or human germline development is indicated. Adapted from Schuh-Huerta & Reijo Pera, 2011.
The seminiferous tubule serves as the sperm production center, where approximately 123 x 106 spermatozoa are produced from germ cells daily, or about 1000 sperm/second (Amann et al., 1980; de Rooij, 2009). Developing germ cells are arranged along the basement membrane in a highly ordered sequence and extend into the lumen of the tubule. At the most basal portion of the tubules lies the spermatogonial stem cell (SSC) population, closely associated with the adjacent Sertoli cells. Morphologic analysis of the various germ cells reveals at least 13 recognizable germ cell types in the human testis (Heller & Clermont, 1963, 1964). Each cell type is thought to represent a different step in spermatogenesis. From the least to the most differentiated, they have been named dark type A spermatogonia (Ad); pale type A spermatogonia (Ap); type B spermatogonia (B); preleptotene (R), leptotene (L), zygotene (z) and pachytene primary spermatocytes (p); secondary spermatocytes (II); and Sa, Sb, Sc, Sd1, and Sd2 spermatids (Figure 3). The early, type A spermatogonia are the most interesting germ cell type from a stem cell point of view (de Rooij, 2009). In fact, time-course studies using GFP-based reporters with early type A, type Ad and type Ap spermatogonia in the mouse revealed that the early type A cell has the ability to divide, self-renew, and give rise to the Ad and Ap sun-populations (Nakagawa T. et al., 2007). These observations provide evidence for the existence of SSCs in the testis and their clonal behavior is protypical of other adult stem cells.
It is currently thought that pale type A (Ap) spermatogonia in the basal, stem cell niche of the seminiferous tubule divide at 16-day intervals and differentiate to type B spermatogonia, which then become spermatocytes (Clermont, 1972). The ability of SSCs within the testis stem cell niche to undergo stem cell renewal is governed by several known factors. The growth factor-receptor kit ligand/c-kit receptor system and the niche factor glial cell line-derived neurotrophic factor (GDNF) are important in this process (Oatley & Brinster, 2008). In fact, spermatogenesis in the rat is dependent on c-Kit receptor activity, whereas spermatogonial stem cell renewal may be c-kit independent (Dym, 1994). GDNF appears to provide a significant stimulus to self-renewal of SSCs through receptors for GDNF on SSCs such as c-Ret and GFR-1(Meng et al., 2000). Despite this, our knowledge of other receptor-ligand systems that control human SSC renewal is limited at this point. During spermatogenesis, the cytoplasm between spermatogonial daughter cells remains conjoined after mitosis, forming cytoplasmic bridges between adjacent cells (Ewing et al., 1980). Cytoplasmic bridges are thought to be important for synchronized cellular proliferation, differentiation, and possibly regulation of gene expression. Thus, SSCs and early spermatogonia in the adult testis are critical for germ cell renewal and differentiation into sperm and raise important questions about the source of proliferative and differentiation signals for spermatogenesis. The majority of stages in mouse spermatogenesis delineated above are translatable to the human germ cell development pathway except for differences in the timing of each stage during development.
Cells of the Human Germ Line Sequence. See text for details. With permission from Kee et al, 2009.
Under the premise that male and female gametes must be replenished, several investigators have queried the existence of elusive germline stem cells. Additionally, the pluripotency potential of embryonic germ cells and their similarity to mESCs has fueled the speculation about the existence of spermatogonial stem cells and their true differentiation potential both in vivo and in vitro. There is compelling data proving the existence and plasticity of testicular germline stem cells in the mouse and more recently the human testis. The exploration of germline stem cells in the human ovary has been confusing because of findings that challenged the long-held notion that females are endowed with a finite supply of oocytes. For instance, Johnson and colleagues observed that a small population of germline stem cells (GSCs) reside in the ovarian surface epithelium in the mouse and can undergo self renewal of the follicular pool within 24 hours (Johnson et al., 2004). However, these results have not been corroborated (Telfer et al., 2005). Johnson et al. reported that bone marrow stem cells enter the ovarian follicular pool through the vasculature and could provide a source for ovarian stem cells (Johnson et al., 2005). Despite the proof of successful transplantation in this study, they failed to demonstrate meiosis in the oocytes generated from ovarian stem cells or bone marrow-derived stem cells (Telfer et al., 2005). Furthermore, it was not clear whether these ovarian stem cell-derived oocytes could be artificially fertilized. Based on these findings, the existence of germline stem cells in the adult ovary remains unknown.
Evidence for stem cells in the adult testis was first provided by Brinster and colleagues in 1994 when they transplanted a putative SSC population into mice and observed complete spermatogenesis with transplanted cells (Brinster RL & Zimmermann JW, 1994). Recent research has sought to characterize the true stem cell potential of early spermatogonia within the seminiferous tubule. Kanatsu-Shinohara et al first reported the generation of pluripotent stem cells from the mouse testis (Kanatsu-Shinohara et al., 2004). In their study, a population of cells termed germ line stem cells (GSCs) were isolated from neonatal mouse testis and propagated in culture (Kanatsu-Shinohara et al., 2003). Subsequently, they found that cell colonies with morphology quite distinct from GSCs, termed ESC-like cells, also appeared in culture. The formation of both GSCs and ESC-like cells depended on a GDNF signal and only ES-like cells expanded in regular mESC media. The expression profile and imprinting profiles indicated that the ES-like cells were more like ESC than GSCs. The definitive test of pluripotency or multipotency in stem cells is to transplant them and assess their ability to form all three germinal layers. In the case of spermatogonial stem cells or their transformed cell types, the ability to form germinal layers and sperm was tested following transplantation. Interestingly, transplantation of ESC-like cells into seminiferous tubules gave rise to teratomas while GSC transplants led to spermatogenesis without teratomas. When ESC-like cells were transplanted via subcutaneous delivery, teratomas containing all three germ layers formed. These ESC-like cells also had the potential to develop into various other cell types, including mature germ cells, showed chimera formation and germ line transmission. More recently, a study by Simon et al. revealed that when putative mouse SSCs were recombined with organs of fetal or neonatal origin, these cells had the ability to transdifferentiate into cells of all three germ layers as well as uterine, prostatic and skin epithelia (Simon et al., 2009). Thus, these experiments in rodents reveal that GSCs and ESC-like cells have very different stem cell characteristics. Unlike with neonatal testis, the authors were unable to generate ESC-like cells from adult mouse adult testis.
A major finding was reported in 2006 by Guan et al. wherein they successfully derived pluripotent stem cells from the adult mouse testis (Guan et al., 2006). With the introduction of a Stra8-eGFP reporter in which GFP expression was regulated by Stra8 promoter activity, ES-like cells were separated from a heterogenous population of testicular cells. When these isolated ES-like cells were grown on mouse embryonic fibroblasts or cultured in medium containing LIF, they evolved into a subpopulation of cells that the authors termed multipotent adult germline stem cells (maGSCs). The pluripotency potential of maGSCs was verified by RT-PCR, in vitro differentiation to all three somatic germ layers, and by successful teratoma formation in vivo. Another transplantation study by Nakagawa et al. in 2007 employed the Neurog3 (Ngn3) promoter to induce GFP expression and thereby enrich for two populations of undifferentiated spermatogonia (Nakagawa T. et al., 2007). The researchers took advantage of the expression of NGN3 on undifferentiated spermatogonia and, from their sorting studies, the first population of cells maintained the SSC progenitor pool through self-renewal while the second population revealed a pool of SSCs that diminished with age. More importantly, the study by Nakagawa and colleagues suggested that the population of SSCs in mice testes is ~2000 cells, substantially less than previous estimates of ~35000 cells (Nakagawa T. et al., 2007). A population of pluripotent stem cells in the adult mouse testis was again confirmed by Ko et al. in 2009. The authors showed that GSCs obtained from the adult mouse testis traverse through unipotency before conversion into multipotent ESC-like cells (Ko et al., 2009). They concluded that that the number of GSCs and culture duration are defining factors in deriving pluripotent stem cells from the germline: they termed these cells germline-derived pluripotent stem cells (gPSCs). In characteristic fashion of ESC-like cells, gPSCs demonstrated in vitro differentiation to all three somatic cell layers, teratoma formation and germ line transmission. Thus, several reports have documented the production of multi- or pluripotency germline stem cells in the mouse.
In parallel to these studies of mice multipotent germline stem cells, several groups have reported a collection of genes and biomarkers that are non-exclusively expressed by mouse SSCs (Reviewed in Caires et al., 2010). These include receptors and downstream facilitators of GDNF action such as GFR1 and RET proteins (Naughton et al., 2006). The gene Ngn3 is also highly expressed on undifferentiated spermatogonial stem cells (Yoshida et al., 2004). The signaling activities of the PI3 Kinase family acting through AKT proteins are also important for SSC self-renewal because blocking these pathways suppresses GDNF activity and reduces spermatogenesis in mice (Oatley et al., 2006). Other molecules expressed on SSCs are Oct4, Bclb6, Etv5, Lhx1 and Nanos2 (Caires et al., 2010). In the future, we hope to employ these markers to more accurately isolate and definitively characterize putative SSC-like cells.
Based on the success in the adult rodent testes, several investigators have attempted the same types of studies in the human. In a landmark study, Conrad and colleagues devised a method by which they could harvest adult spermatogonial stem cells and subsequently reprogram them into pluripotent cells (Conrad et al., 2008). They employed the use of adult testis tissue from which they harvested a mixed cell population. The single cell suspension was then cultured in vitro in the presence of GDNF, as mouse studies have shown this growth factor to be critical for self-renewal of SSCs. They then purified SSCs by magnetic-activated cell separation (MACS) with CD49f bound beads. Further selection on collagen and laminin plates led to a highly enriched population of spermatogonial cells. When cultured in the same media used for hESCs and supplemented with LIF, the spermatogonial cells gradually arranged in multilayered, clustered colonies and displayed features consistent with pluripotent stem cells. The researchers termed these cells human adult germline stem cell (haGSC). Extensive characterization of haGSCs was then carried out by analyzing gene and protein expression and conducting microarray analysis for genome-wide changes in expression. Epigenetic reprogramming was assessed and various pluripotency markers were measured. Finally, the cells were karyotyped and a teratoma formation assay was successful in immunodeficient mice (Conrad et al., 2008). Overall, the authors observed significantly different expression profiles in haGCSs compared to the parent spermatogonial cells, and haGSCs acquired expression profiles similar to hESCs. Although a complete analysis of a novel cell population in the human testis, several caveats to this research exist. Entire testicles were used to derive spermatogonial cells, bringing into question the feasibility of this approach for clinical use (Kee et al., 2010). In addition, the global gene expression patterns of plurpotency markers obtained from these haGSCs have been challenged as being more closely associated with fibroblasts than hESCs (Ko et al, 2010). Nevertheless, the above experiments underline the concept that adult germline stem cells and by extension PGCs may share basic properties with hESCs.
To address the issue of limited availability of starting material, an alternative protocol for generating human pluripotent stem cells was reported by Kossack et al., 2009. Their approach required only a testis biopsy as starting substrate. The biopsies were enzymatically digested and testicular cells released in suspension were grown in basic media until small colonies of cells began to form. Selection for cells in colonies was performed by manually dissecting out colonies and then propagation on mouse embryonic fibroblasts (MEFs) in hESC culture conditions, supplemented with bFGF. Under these conditions, the spermatogonial cells acquired a hESC-like morphology and physical characteristics, and were termed human multipotent adult germline stem cells (hMGSCs). Careful analysis revealed that hMGSCs were karyotypically nomal, expressed both pluripotency and early germ cell markers and contained a generally hypomethylated DNA pattern consistent with hESCs rather than somatic cells. Albeit spontaneously differentiating to cells of endodermal, mesodermal, and ectodermal lineages, hMGSCs did not successfully form teratomas in vivo. Therefore, despite a simpler methodology using limited substrate, this study suggested that hMGSCs, unlike true hESCs, might be only multipotent and not fully pluripotent. A third study also used testicular tissue fragments as a cell source from which to separate spermatogonial stem cells (Golestaneh et al., 2009). Using 1g of testicular tissue, much larger than routine testis biopsy, they also derived pluripotent stem cells after isolated seminiferous tubules were enzymatically digested and grown in hESC media (supplemented with bFGF and TGF-β but not grown on MEF feeders). After several passages, they observed medium-sized colonies of ~500 cells which were termed ESC-like cells. As expected, these cells expressed pluripotency markers and they were able to differentiate to endoderm, mesoderm, and ectoderm. Similar to the finding of Kossack et al, only small teratomas formed from the transplanted ES-like cells, and only when large cell numbers (~2x106) were used. Thus, this study also suggests that the pluripotency of these ES-like cells may not be identical to true hESCs.
As eluded to above, a major limitation of deriving SSCs is the requirement for generous amounts of human testicular tissue as starting substrate. Protocols need to be refined to allow pluripotent stem cell generation from the smallest amount of testis tissue substrate to make this technology feasible for clinical use. Another limitation is the low efficiency of isolating SSCs from testis tissue and of generating pluripotent stem cells from SSCs. Optimization of culture conditions may reduce these inefficiencies in the future. Despite this, research over the last decade has uniquely highlighted the stem cell potential of SSCs derived from the human testis and their remarkable similarity to the differentiation potential of ESCs. A major drawback has been the inability of the SSCs to consistently produce large teratomas. This likely indicates that SSCs are only multipotent and not pluripotent (Kee et al., 2009), a distinction that has implications for the therapeutic potential of SSCs. Will they only be useful for obtaining sperm or will they have a broader potential for cell-based therapies in unrelated target tissues? Finally, the relatively invasive procedure for isolation of adult human germline stem cells from the testis compared to derivation of iPSCs may favor the latter approach as a preferred methodology for clinical use.
Human infertility is remarkably common, affecting 10-15% of couples. Most commonly, infertility is caused by defects in germ cell development (de Kretser, 1997; Skakkebaek et al., 1994). Microdeletions in the AZF (Azoospermia Factor) region of the human Y chromosome are the most common cause of human infertility and Non-Obstructive Azoospermia (NOA) in men. The associated clinical phenotypes are typically azoospermia or severe oligospermia, and on diagnostic testis biopsy reveal the complete absence of the germ cell lineage, to maturation arrest of spermatogenesis, to the production of a small number of germ cells (Gonsalves et al., 2005). The AZF region is highly repetitive and consists of numerous palindromic regions thought to have arisen out of repeated rounds of gene duplication and inversion (Kuroda-Kawaguchi et al., 2001; Skaletsky et al., 2003). The highly repetitive nature of the AZF region makes it particularly prone to homologous recombination between direct repeats and resulting in deletions. There is now a fairly comprehensive chromosomal map of the AZF regions with three specific regions currently identified, AZFa, AZFb and AZFc, that represent multi-gene segments on the Y chromosome (Kuroda-Kawaguchi et al., 2001). The most commonly deleted of these three is the AZFc region, resulting in phenotypes that range from complete absence of the germ cell lineage (termed Sertoli Cell Only [SCO] syndrome) to oligospermia (Reijo Pera, 1995, 1996). In spite of their deletion frequency, the function of genes that map to the Y chromosome AZFc are still poorly understood. This region harbors six multi-gene families including the RBMY, PRY, VCY2, CDY1 and DAZ genes (Kuroda-Kawaguchi et al., 2001). Intriguingly, all of the protein-coding AZF genes are expressed exclusively in germ cells and some testicular cells, suggesting their importance in germ cell development (Navarro-Costa et al., 2010). Although precise functions have not been pinpointed, the predicted sequences and protein structures encoded by these genes provide a glimpse into their potential function. For instance, DAZ and RBMY genes are thought to be involved in RNA binding and transport, thereby positioning them as regulators of mRNA translation during spermatogenesis (Collier et al., 2005; Kee et al., 2009; Lee et al., 2006). Meanwhile, CDY and BPY2 genes are likely regulators of chromatin and genome organization (Caron et al., 2003; Lahn et al., 2002). Our overall understanding of infertility genetics will be greatly advanced by studying the molecular contribution of genes such as DAZ to meiotic recombination, DNA repair, epigenetic reprogramming and the development of cancer and other clinical aberrations.
Our knowledge about mouse embryo and germline development from mESCs has allowed for in vivo and in vitro modeling of germline development. However, very limited access to early-stage human embryos and especially primordial human germ cells has greatly reduced the ability to conduct similar investigations into human germline development, let alone modelling it in vitro. This section reviews the highlights of experiments conducted during the last decade using in vitro model systems of mouse and human germline development from mESCs and hESCs (Table 1).
A Summary of the Recent Efforts to Derive Gametes from ESCs and iPSCs. Note: mESC – mouse embryonic stem cells; hESC – human embryonic stem cells; EB – embryoid body; BMP – bone morphogenetic protein; Mvh – mouse Vasa homolog; RA – retinoic acid; ICSI – intracytoplasmic sperm injection; MEF – mouse embryonic feeders.
The mouse has proven to be a robust and dependable system for analysis of germline development. Studies conducted in vivo during mouse early development have greatly informed in vitro investigations and have generated promising prospects for creating gametes from stem cells. The earliest in vivo evidence for embryonic stem cell-derived germ cells was suggested from experiments performed by Bradley et al. in 1984. They generated germline chimeras after injecting mESCs into blastocysts (Bradley et al., 1984). This work suggests that mESCs, if cultured under the right conditions, could be differentiated to PGCs. We now know that mESC share many developmental features and markers with PGCs which further supports the use of mESCs as a starting point. This is most convenient as mouse PGCs are difficult to grow and differentiate in vitro due to limited viability in culture (Resnick et al., 1992; Farini et al., 2005). Thus, we have learned a lot over the two decades about mouse embryonic and germ cell development to guide us as we more forward.
The first report on the creation of putative germ cells in vitro was reported in 2003. In this study, mESCs were transfected with a reporter Green Fluorescent Protein (GFP) under the control of an Oct4 enhancer sequence (Hubner et al., 2003). The withdrawal of LIF, a factor that promotes self-renewal in mESCs, promoted PGC development and resulted in an increase in GFP-positive cells. More importantly, the GFP-positive cells assumed a follicle-like appearance and showed overall structural and molecular similarities to oocytes. Tooyaka et al. used a similar, reporter-based approach to derive male germ cells that resembled mouse spermatozoa (Tooyaka et al., 2003). They utilized the mouse VASA homologous gene promoter Mvh to drive GFP expression in mESC, which then spontaneously differentiated to embryoid bodies (EBs) in the absence of LIF. The putative PGC population when transplanted into a mouse neonatal testis, differentiated to give rise to spermatozoa. These two landmark studies set the stage for further investigation of deriving gametogenesis from mESC.
In 2004, Geijsen et al. derived male gametes from EBs after culture in the presence of retinoic acid (RA), a key paracrine factor produced in the testis (Geijsen et al., 2004). Additionally, by selecting cells that only expressed SSEA-1 and Oct4, the authors were able to enrich for mature, post-meiotic germ cells that were then capable of forming blastocytes after injection into oocytes. It was later shown by Kerkis et al. that the divergence of male and female germ cell programs during spontaneous differentiation of EBs in vitro was dependent on the length of culture time (Kerkis et al., 2007). Several attempts at oocyte or follicle derivation from mESC have been made using the EB-based approach with various culture and attachment conditions all of which yielded oocyte-like cells that lacked critical structural features such as the zona pellucida or expression of meiotic molecular machinery (Lacham-Kaplan et al., 2006; Novak et al., 2006). Other studies have employed slightly different approaches to derive putative oocytes from mESCs. Qing et al. obtained PGCs from cultured EBs and then co-cultured them on a layer of fetal ovarian granulosa cells and observed an increase in the meiotic marker SCP3 and upregulation of oocyte-specific genes such as Gdf9. The GDF9 positive cells probably resembled an immature oocyte as they lacked a zona pellucida and did not express mature oocyte proteins such as ZP4 (Qing et al., 2007). In an alternative approach developed by Salvador et al., a Gdf9-driven GFP reporter assay was introduced into mESC. The mESCs were then differentiated to EBs and GFP-positive cells were isolated from the EBs to isolate PGCs (Salvador et al., 2007). In summary, these studies may have derived primitive oocytes from mESCs, but failed to accomplish meiotic entry in the final cell products.
An alternative approach to deriving female germ cells was employed by Nicholas et al. by using a germ cell-specific reporter, ΔPE:Oct4: GFP. This reporting system was previously employed by Hubner et al. to separate GFP-expressing ESCs, PGCs and primary spermatogonia in the mouse (Nicholas et al., 2009). After verifying the expression of GFP on these subsets of cells, the authors spontaneously differentiated mESCs carrying this reporter to EBs, then FACS-sorted GFP positive cells, and observed a higher expression of germ cell and oocyte markers in the selected cells. They then assessed whether ESCs could give rise to mature oocytes in vivo by first forming aggregates of the GFP-positive cells with fetal ovarian tissue and then transplanting them to the kidney capsule. In doing so, they observed mature oocytes of confirmed ESC origin, some of which resembled primordial follicles with a surrounding layer of granulosa cells. An important insight from this work was that the timing of germline development, particularly with oocyte maturation, is a major parameter in deriving gametes. Furthermore, it highlights that the use of transplantation in combination with in vitro culturing may greatly improve the success of gamete production from mESCs.
The first study to show virtually complete gametogenesis in vitro was conducted by Nayernia et al. in 2006. A two-stage approach was employed to first derive pre-meiotic PGCs from mESCs with a Stra8 driven GFP reporter induced with RA addition (Nayernia et al., 2006). GFP-positive cells were then separated by Fluorescence Activated Cell Sorting (FACS), grown in RA-supplemented medium and transfected with a second reporter, Prm1-dsred. The second reporter enriched for PGCs that had undergone meiosis and formed red-fluorescing, haploid cells. After further RA treatment, the haploid sperm-like cells were then injected into mouse oocytes by Intra-Cytoplasmic Sperm Injection (ICSI) to test the functionality of the derived germ cells. Indeed, blastocysts formed and viable offspring born that eventually succumbed to developmental complications and died prematurely. Potentially, the epigenetic reprogramming of the derived germ cells may not have been complete. Nevertheless, these efforts provided functional proof of gametogenesis in vitro.\n\t\t\t\t
Additional studies demonstrating in vitro spermatogenesis have employed organ culture systems as far back as 1960. Since then, there has been tremendous progress in the study of germ cell development, particularly in the mouse. This is best exemplified by a very recent study by Sato et al. in which functional mouse sperm were generated in vitro by employing a novel organ culture method. Specifically, they improved on existing organ culture methods by placing neonatal (mouse pup) testis fragments in FBS-soaked agar plugs in culture (Sato et al., 2011). With these plugs, they controlled the gas:liquid interface and also added exogenous factors. Their study conclusively showed through an analysis of reporter expression before and after meiosis, that functional, haploid spermatozoa were generated that could fertilize oocytes and give rise to viable, healthy pups. In addition, the generated pups were also shown to be naturally fertile as adults. In summary, attempts to generate germ cells from mESCs have yielded cells that resemble sperm or oocytes in gene expression, ploidy, epigenetic reprogramming and fertilization ability. However, these studies have also revealed inregularities in the duration of meiosis in culture, in the morphological features of oocytes, in the viability of offspring generated and in the germline transmission of exogenous genes to the offspring (Chuva de Sousa Lopes et al., 2010).
The evidence for germline differentiation from hESCs is more complex; as such literature is more preliminary than that from the mouse. Furthermore, doubts regarding the extent of pluripotency in hESCs vs. mESCs and the ethical constraints of testing the functionality of human germ cells are legitimate considerations with this research. Despite this, there is a tremendous need to understand human germline formation, the genes that control spermatogenesis and oogenesis and from a clinical standpoint, a need for in vitro derived functional gametes. Efforts to derive human germ cells began with a study by Clark et al. in 2004 in which spontaneously differentiated hESCs were used to create embryoid bodies (EBs) (Clark et al., 2004). Within the EB mixed cell population, they identified the levels of several known germ cell markers such as DAZL, STELLAR and c-KIT. Additionally, they observed that VASA levels were induced within a putative PGC population and other markers of meiosis were also upregulated. Collectively, their data indicated that PGCs had formed but had not entered meiosis. An important facet of their study was the identification of germline-associated genes such as DAZL and c-KIT as expressed in undifferentiated hESCs, which reminds us that hESCs may not be truly equivalent to cells of the ICM (Clark et al., 2006). The methods of Clark et al. were optimized in a follow-up study in which BMP-4, -7 and -8 were added exogenously during EB formation from hESCs and higher VASA expression was observed in the putative PGC population (Kee et al., 2006). Therefore, similar to the mouse model, the role of BMPs in human germline specification may be important. More recent studies using mESCs in vitro by Young et al. have illustrated how BMP2 and BMP4 but not BMP8b are important inductive agents for specifying the germ cell lineage in EBs (Young et al., 2010). These results help to clarify our understanding of BMP action in the germline as the goal of deriving haploid germ cells is pursued.
Chen et al. and Tilgner et al. also derived human PGCs from substrate EBs in independent studies. They observed that their EBs contained small structures that resembled ovarian follicles and that tested positive for c-KIT and low amounts of VASA protein (Chen et al., 2007). They also observed these structures in hESCs that were spontaneously differentiated in adherent cultures, suggesting that EBs are not essential for germ cell differentiation, at least in the female lineage. Meanwhile, Tilgner et al. used a more sophisticated strategy to separate germ cells from EBs and adherent cultures through FACs sorting for cells expressing the surface marker SSEA-1, a protein associated with very early germ cells (Tilgner et al., 2008). Despite evidence of complete epigenetic reprogramming in these early germ cells, the authors did not observe meiosis. In 2009, Park et al. built upon the findings of Tilgner et al. by isolating differentiated cells enriched in SSEA-1 as well as c-KIT expression. However, they used an interesting differentiation strategy and co-cultured hESC colonies with stromal cells from the human fetal gonad (Park et al., 2009). In this model, the paracrine factors produced from fetal stromal cells would ideally resemble those made in vivo, thereby theoretically inducing primitive germ cells to differentiate into PGCs. Their efforts were successful, yielding SSEA-1 /c-KIT positive PGCs that expressed numerous germ cell markers such as VASA, PRDM1 and DAZL and revealed evidence of partial epigenetic reprogramming.
Based on the findings of spontaneous differentiation of hESCs to PGCs, researchers have entertained the possibility that a small population of cells within a typical hESC population is pre-destined to become germ cells. Based on this hypothesis, several groups have explored whether simply optimizing culture conditions of hESCs can promote or induce germline differentiation. Stice and colleagues first reported that by the simple addition of basic FGF (bFGF) to hESCs growing on inactivated MEF feeder cells, they could produce approximately 69% VASA-positive cells with increases in expression of germline and meiotic markers (West et al., 2008). These data seem rather optimistic given that most other groups have reported much lower germ cell numbers under similar culture conditions. Concurrently, Bucay et al. modified their culture conditions by lowering the confluency of hESC colonies and observed a subpopulation of cells expressing CXCR4, a membrane receptor implicated in PGC migration (Bucay et al., 2009). Upon purification, the CXCR4-expressing cells could be grown on a laminin substrate and gave rise to putative PGCs and Sertoli cells. In recent studies, West et al. explore the effect of modulating KIT ligand (KIT-L) and BMP4 activities in culture of hESCs and observed that these are required for early germ-like cell (GLC) derivation (West et al., 2010a).
A major milestone in germline differentiation of both male and female human PGCs is the initiation and completion of meiosis. Deriving haploid gametes in vitro is a significant feat and one that researchers have struggled with for years in human germline differentiation. Kee and colleagues derived human haploid gametes for the first time in 2009 by introducing three major genes of the Deleted-in-Azoospermia (DAZ) family, DAZ, DAZL, and BOULE in hESCs and then differentiating the cells spontaneously in adherent culture conditions (Kee et al., 2009). Although a low number of haploid (1n) cells were observed (~2%) seven days after differentiation, they expressed numerous germ cell-specific markers and meiotic spreads indicated the presence of SCP3, a key member of the synaptonemal complex that forms during meiosis. These data also reinforce the importance of the DAZ family of genes for early (DAZL) and late (BOULE, DAZ) primordial germ cell formation. Since this work was published, another group has demonstrated meiosis in in vitro derived PGCs: West et al. had previously shown that they could isolate early VASA-positive germ-like cells (GLCs) and were able to subclone at least three populations of these cells from their mixed cultures and propagate them through at least 50 serial passages (West et al., 2010 . These cells were then be differentiated with FBS into a more homogenous population and the majority of cells entered meiosis (~71%) while also expressing germline and meiotic markers (West et al., 2010. Taken together, these studies offer alternative and compelling strategies for derivation of PGCs from hESCs. While one (West et al., 2010 suggests that GLCs are a natural clonal subpopulation of hESCs that can be propagated in vitro, the other (Kee et al., 2009) argues in favor of an active, gene-driven induction of germline differentiation.
Ongoing advances in reprogramming of human somatic cell to pluripotent stem cells (iPSCs) or direct reprogramming of somatic cells to specific cell lineages, are a legitimate avenue for autologous, patient-derived stem cell therapies. By applying similar genetic approaches used for human ESCs, iPSCs can now be directed to give rise to cells of the germ cell lineage. We summarize here some of the recent efforts in this area. The use of human iPSCs (hiPSCs) to derive gametes was first shown by Park et al. in a study that also compared the derivation efficiency to hESCs (Park et al., 2009). In short, they grew hiPSCs on a feeder layer of fetal gonad stromal cells and subsequently isolated SSEA-1 + / c-KIT + cells which they characterized as a putative PGC population. These human induced PGCs (hiPGCs) expressed several germline markers but did not show evidence of imprinting erasure, a key feature of early PGCs. Further evidence for the creation of haploid hiPGCs from male and female hiPSCs was provided by Panula et al. recently wherein they used a GFP reporter under the control of the Vasa promoter to select for putative germ cells from spontaneously differentiated cultures (Panula et al., 2010). The Vasa-GFP transduced hiPSCs were differentiated adherently in feeder-free conditions in the presence of BMPs, giving rise to approximately 5% GFP-positive PGCs. These PGCs expressed a number of germ cell markers such as Prdm1A, ACTC, Gata6, Pelota and IFITM1. More importantly, the GFP-positive hiPGCs expressed the meiotic marker SCP3 in both punctate and elongated patterns, indicative of early and late meiosis, respectively. Interestingly, when compared to PGCs derived from both male or female hESCs, the efficiency of hiPGC derivation appears higher, suggesting that hiPSCs may be a better starting substrate for germline differentiation. In summary, these two investigations provide encouraging results about the ability to use hiPSCs to derive gametes in vitro. Although the differentiation potential of hiPSCs may vary greatly from one cell line to another, they appear to have strong potential as a genetic model system to study human germ cell development.
Currently many men suffer from non-obstructive azoospermia as described earlier that results in complete sterility. In addition, in the U.S. alone there are 55,000 childhood cancer survivors annually, many of whom were unable to bank sperm before receiving sterilizing treatments. Similarly, women have a finite supply of reproductively competent oocytes while others undergo premature ovarian failure, making childbearing difficult or impossible. Alternative options for parenthood in these cases are not always simple or inexpensive. Although sperm donation is economical, oocyte donation is quite expensive and the use of donated embryos is unusual (Nicholas et al., 2009). For men, recent strategies
Comparison of in vivo Germline Development and in vitro Germ Cell Derivation from ESCs and iPSCs.A depiction of in vivo development of germ cells and gametes from the mammalian embryo showing that embryonic stem cells (ESCs) originate from primitive ectoderm, by way of the inner cell mass (ICM). Primordial germ cells then migrate to gonads where they undergo self-renewal in the form of spermatogonial stem cells (SSCs) in the testis and oocytes in the ovary. On the right is a schematic of the cell lineages derived in vitro. ESCs cultured in dishes can be differentiated to PGCs via methods summarized in Table 1. PGCs cultured in vitro, at least in the mouse, can transform to embryonic germ (EG) cells. There is also evidence a subpopulation of hESCs cultured in vitro behave like EG cells. Finally, somatic cells can be reprogrammed with addition of Oct4, Sox2, Klf4 and c-Myc transcription factors to induce a stem cell-like fate. iPSCs can then be induced to form PGC-like cells or EG-like cells. Finally, ESCs, PGCs and iPSCs can all form teratomas when injected in vivo demonstrating their pluripotency.
such as extracting low numbers of testis sperm after prior localization with Fine Needle Aspiration (FNA) mapping, offer the hope of fatherhood for some candidates (Beliveau et al., 2011; Natali et al., 2011).
Although such strategies are gaining in popularity, the pregnancy success rates remains at about 30-40% using sophisticated in vitro fertilization (IVF) techniques (Centers for Disease Control [CDC], 2008). In addition, with these reproductive technologies, there remain important safety concerns about de novo sex chromosomal disorders, birth defects and imprinting-related disorders such as Beckwith-Wiedeman syndrome in offspring (Childs et al., 2008). Therefore, there is an obvious clinical need for high quality, in vitro-derived gametes. However, the prospect of employing current protocols and reagents to derive human gametes from hESCs appears unlikely at this time. On the other hand, the use of iPSCs and alternative stem cell sources such as adult stem cells, hold great promise in thisregard. In the foreseeable future, patients with genetic disorders affecting fertility could theorectially donate somatic cell biopsies that could then be reprogrammed into iPSCs and genetically modified to normal and subsequently utilized for gametogenesis in vitro.
However, there are numerous challenges to the application of iPSCs for clinical use (Hanna et al., 2010). For one, the exact level of authenticity and experimental proof required for the safe use of iPSC and hESC derived gametes in the clinic is entirely unknown. To address this issue, there are at least three major areas that the research community can and should address before taking in vitro-derived gametes to the clinic. Firstly, the chromosomal composition of the iPSCs must be identical to the original patient from where they were derived. There is now sufficient data detailing the gene mutations and copy number variations arising in iPSCs during reprogramming and clonal expansion. It would be wise to carefully screen for these variation in patient-derived samples (Reviewed in Panopoulos et al., 2011). Moreover, frequent chromosomal aberrations arise during meiotic recombination so it would be necessary to examine the fidelity of meiosis in gametes in vitro. Secondly, it is important to check for the proper erasure and subsequent re-establishment of maternal and paternal imprints in PGCs derived from both iPSCs and hESCs. There is published work with hESCs and iPSCs that has attempted to characterize imprinting status and DNA methylation patterns in these derived cells; the preliminary evidence seems to indicate that in vitro derived hiPGCs appear to undergo partial to full imprinting erasure (Kee et al., 2009; Panula et al., 2010). Whether the correct imprints are restored later on during germ cell development remains unknown. Thirdly, the most infallible method to test full functionality of in vitro-derived gametes is to test their ability to fertilize, form a blastocyst and viable offspring. In the mouse, this has been tested despite the premature death of offspring (Nayernia et al., 2006). One obstacle is how can we overcome ethical boundaries and challenges to do similar tests with human gametes? Perhaps for now, the primary medical application of human stem cell-derived gametes would be to use them as a reproductive toxicological screen for pharmaceutical compounds and other chemicals.
In the last decade, much progress has been made in our understanding of mouse and human embryology and embryonic stem cells. We have learned that complex genetic pathways that underlie the pluripotency aspects of hESCs and mESCs also underline our inability to easily control and direct these cells toward a specific lineage. In addition, the advent of diverse strategies to ‘reprogram’ somatic cells has opened up an almost limitless access to patient-specific stem cells that if used correctly, could provide very powerful cell-based therapies. Scientifically, the biology of germline development has always been an popular area of exploration for embryologists and stem cell biologists, especially because germ cells are unique in their ability to transmit genetic information from one generation to the next. If we can understand how germ cells develop from ESCs at the cellular and molecular level, we can apply this information to the derivation of male and female gametes. The goals of gamete formation include: 1) to address immediate health issues such as infertility in men and women due to sperm and egg dysfunction or absence; 2) to produce gametes that can be fertilized and produce an almost limitless source of mammalian embryos and ESCs for the study of specific diseases; 3) to devise methods with which to target hereditary and non-hereditary germline mutations or chromosomal abnormalities during the earliest stages of germ cell production.
The studies summarized in this review have shown that multipotent ES-like SSCs can develop into somatic cells of all three germ layers, but their ability to differentiate to the germline remains unclear or untested. In addition, it is believed that SSCs may only be multipotent and will be useful only for autologous transplantation and maybe for only a few tissue types. In this regard, one promising avenue for SSCs is differentiation down the spermatogenic pathway. Finally, there is a limited expansion potential of SSCs compared to iPSCs or hESCs and the imprinting status of these cells is less well defined than that of hESCs. A similar approach as used by Kee et al. in 2009 to overexpresss DAZ genes in hESCs could potentially be applied to differentiate SSC’s to spermatids or sperm in vitro. Alternatively, one could envision that the research on in vitro-derived human oocytes could be similarly advanced and lead to a better understanding of the concept that there are renewable ovarian stem cells in humans. In conclusion, the potential of ESCs and iPSCs to be used for cell-based therapy is now being realized. Major challenges, both scientific and clinical, still exist in deriving germline cells that look and behave as reliably as their natural counterparts. With further advances in technology and the elucidation of new pathways in gerrmline function in the mouse and human systems, we predict that these challenges can be met and overcome in the future.
Keypoints:
Mouse and human embryonic stem cells provide the ideal substrate for germline differentiation, both in vivo and in vitro.
The mammalian germline is established as primordial germ cells immediately prior to gastrulation in mice and humans, and undergo similar physiological and molecular events.
Induced pluripotent stem cells (iPSCs) and adult stem cells may provide alternative sources of pluripotent and multipotent stem cells with less potential for host rejection and decreased tumorigenicity.
Testicular stem cells with multipotent and even pluripotent potential have been isolated in mouse models and, more recently, in humans.
The in vitro derivation of early male and female germ cells is now achievable from mESCs, hESCs and human iPSCs with the application of various reporter systems and through embryoid body (EB) formation.
The functional responsibility of the immune system (humoral and cell-mediated alike) is to protect against infection by destroying various infectious agents when such agents attack the body or are introduced through vaccination [1]. The functioning of the immune system is coordinated and maintained by a sequence of highly regulated and physiological mechanisms which aids the identification and recognition of both body cells and foreign cells [2].
The body’s immune units usually coexist with other cells of the body that carries a self-marker molecule. Immune reactions are only triggered when an antigen which could be a microbe, part of a microbe or a molecule is presented to the surface of the cell and perceived by the body defenses [3].
The immune system of humans is made up of two divisions which are innate and acquired immunity. The innate immunity forms the first line of defense immediately after infectious agents are recognized by the body while acquired immunity functions in the removal of pathogens at the later phase of infection [3].
When the immune system is stimulated, it targets and destroys foreign units. Still, in some abnormal situation, the immune system might be insensitive to antigens, hypersensitive to antigens or recognize the cells with self-marker as foreign cells [2].
There are disease conditions that affect the immune system, which leads to different degree and types of conditions known as the Immune diseases. Diseases of the immune system include inherited and acquired immunodeficiency and immune-proliferative disorders which includes malignancies of the immune system (multiple myeloma, lymphoma, and leukemia), autoimmune diseases (rheumatoid arthritis), and immune hypersensitivities (allergies) [4]. Inherited immunodeficiency, also is known as primary immunodeficiency, refers to a large number of immune disorders which alters either or both development and function of the immune system. Primary immunodeficiency implies conditions resulting from loss of function, a gain of function or loss of expression due to monogenic germline mutations [5]. External and environmental factors can induce an adverse effect on the immune system, and this is regarded as secondary or acquired immunodeficiency, which is encountered commonly in clinical practice and could arise from quite a number of conditions [6].
The evolvement of medical practices especially diagnosis and treatment from the usual “one size fits all” approach to a more genetic and detailed patient stratification in a bit to acquire more information about the disease condition and the patient is known as personalized medicine [7].
The complexity of the body defense system and the ability of the cells associated with it to shift between different activation states under physiological and pathological conditions are some of the reasons for diversity in the treatment approach. The immune diseases at times are diverse, and this result in variations in response to therapy. The difference in the disease course also create reasons why there should be the identification of personalized marker for diagnosis of immune disease. Therefore, the use of genetic assessment to determine the best possible therapeutic approach from the numerous available options with different mechanisms, risks, and efficacy are essential [7, 8].
The Precision medicine data types, genomic data in precision medicine, genomic and personalized medicine databases, data sharing, access and use are discussed in this chapter. Also, the use of genomic methods and data in the understanding, diagnosis of diseases using specific biomarkers, monitoring of prognosis using prognosis biomarkers, personalized treatment of immune disorders, monitoring of response to treatment using response biomarkers are also described in this chapter.
Immunity is the ability of the body to prevent infection by resisting the invasion of such a body by harmful microorganism knows as infectious agents. Immunity can be categorized broadly into two types which are:
Innate or Natural Immunity and
Acquired Immunity
The initial host protection against diseases- causing agents is the innate immunity which is mediated by phagocytes. Through germline-encoded pattern-recognition receptors (PRRs), the innate immunity of the human body recognizes microorganisms invading its body. For the immune cells to be activated, different classes of the PRRs, which include Toll-like receptors and cytoplasm receptors recognize distinct and important microbial component of invading microorganisms thereby activating immune cells [3, 9].
Immediately after the detection of non-self-agents by PRRs which could be exhibited on the outer membrane of the cell, in intracellular parts, or released in the bloodstream and fluids of the body tissues, the PRRs then perform the function of opsonization, stimulation of complement and coagulation outflow, phagocytosis, initiation of pro-inflammatory signaling pathways, and inception of apoptosis. These cascades of intracellular signaling induce the expression of overlapping and unique genes which are involved in the inflammatory immune responses and essential in precision medicine. The reaction by the innate immune system is carried out by phagocytes (neutrophils, monocytes, and macrophages), inflammatory mediators releasing cells (basophils, mast cells, and eosinophils), and natural killer (NK) cells [3, 10].
Acquired immunity is the immunity that is developed against an infectious agent by the body after the previous encounter with a pathogen or a type of immunity developed by a child by the exchange of protective materials from mother to child before and after birth or by the injection of such substances. The mediation of adaptive immunity is the function of clonally distributed T and B Lymphocytes whose characteristics are the possession of specificity and memory. Many at times, activation of the innate immune response can trigger acquired immunity. The generation of Helper T cells subsets and the production of cytokines influence adaptive immunity [11, 12].
When naïve T-helpers cells are stimulated by Antigen-presenting Cells otherwise known as APCs, they differentiate into two subsets of T helper (TH) cells such as TH1 and TH2. Interferon-γ (IFN-γ) is produced by TH1 cells that solely promote cellular immunity. TH2 cells, on the other hand, produce interleukin 4, 5, 10 and 13 (IL-4, IL-5, IL-10, and IL-13). Whereas, IL-12 is the propelling source of TH1 separation while IL-4 stimulates TH2 distinction. TH2 is majorly involved in the promotion of humoral immunity [12].
The occurrence of the immunological disease is consequent to the dysregulation of numerous and different part of the human immune system. Fundamentally, the response of the immune system recognizes and eliminates antigens but tolerates its tissues. However, predominant immunopathology lesion is the basis on which the characterization of immune-mediated diseases is based. Immune-mediated disorders can be grouped into immediate hypersensitivity, autoimmunity, immune-complex disease, and delayed-type hypersensitivity. Autoimmunity can be further classified into those mediated by adaptive immunity and those mediated by innate immunity. Most of the disorders lie between the two, which will be best described as positive pathological feedback between innate and adaptive immune mechanisms [13]. Figure 1 below represents the pathogenesis of immune diseases.
Schematic representation of the pathogenesis of immune diseases.
Personalized medicine is the process of tailoring the diagnostic procedures, treatment, and preventive measures towards the characteristics of individual patients to get an optimal outcome for each patient while emphasizing easy accessibility and cost-effectiveness [14]. In the practice of personalized medicine, the characteristics of an individual, including the uniqueness of its genetic profile guide the clinical decision in the treatment. Prognostic, diagnostic and predictive biomarkers are always being searched to guide these clinical decisions, at the same time, ensure that the best treatment is offered to the right patient at the best time [15]. The division of personalized medicine is illustrated in Figure 2.
Diagram showing the different division of precision medicine.
While the method of application of precision medicine is given in Figure 3.
A flow chart representing application method of precision medicine.
Generally, personalized medicine compose of a vast collection of genetic data. The development of power systems has helped to increase the effective use of big data in personalized or precisions medicine over time. Also, the evolution of genomics data offers limitless possibilities in the design of clinical procedures, diagnostic, prevention, addressing and prediction of most favorable therapeutics for many diseases that are related to different regions and lineage [16].
The systematic collection of patient information is now accumulating and gaining complexity, as seen in the case of neuroimaging, which is currently producing above ten petabytes of data every year [17]. Studies in the field of precision medicine research make use of relevant data types such as Imaging data (CT, PET, UltraSound and MRI), bio-sample data (serum, plasma and urine value), molecular data, genomics data (nucleotide sequences), proteomic profiling data (mass spectrometry), digital pathology data, biomedical instrument data (blood pressure, heart rate and insulin level) and clinical data (death/survival data, demographics and medical-based questionnaire) and others [18].
Some of the achievement in Precision medicine has led to solutions, such as the birth of personalized brain models for a patient with intractable epilepsy [19] and the success in epigenetics mechanism of hematopoiesis [20]. The combination and integration of these data types require a sound understanding of the different fields of informatics (data science, data management and data curation) and bioinformatics [18].
A database is an ordered set of structured information or data usually controlled by the database management system (DBMS) in an electronic computer. The data, DBMS and the applications associated with them are called database system or database in short. Each database contains certain types of data; here, we will be introducing some of the database associated with personalized or precision medicine.
The IEDB is a free to use database that is very useful in vaccine and drug development, this database catalogs data such as experimental data on antibodies, Major histocompatibility complex (MHC) binding data from different antigenic sources, Helper T lymphocyte (HTL) and Cytotoxic T Lymphocytes (CTL) epitopes for human and other animal species. This database also aids in prediction and analysis of varieties of epitopes [21]. This database can be accessed through
Lifestyle medicine is the study of association between lifestyle, chronic and immune diseases. PCaLiStDB is a lifestyle database that is channeled towards precision in the prevention of prostate cancer and other diseases associated with lifestyle. The data found in this database are lifestyle associated genes, lifestyle type biomarkers and personalized lifestyle-disease associated predictors [22]. The database link is
ClinGen database provides data that are of clinical importance, this database is funded by the National Institute of Health (NIH), and it is aimed at collecting necessary data for use in precision medicine and research. Data such as clinically relevant gene and variants are retrieved from this database in making precise diagnosis and treatment [23]. This database is accessed via
One of the breakthroughs of medical informatics is the personal genome project database. This is an open-access database that is channeled towards the development of a tool for personalized medicine and advancing research. The database provides a wide range of data for different regions (PGP-UK, PGP-AUSTRIA, PGP-CHINA, PGP-CANADA and PGP-UNITED STATE, etc.). Data such as Genome, Methylome, transcriptome and phenotype data are retrieved from this database for use in the procedure of precise medicine [24]. The database can be linked through
This database was initiated in the early 1960s, and the online version was created in 1985. OMIM is an open-access database that is mainly built for professionals concerned with genetic disorders, a genetics researcher and advance students in medicine. Data such as human gene, genetic disorders, clinical features, phenotype and genes are available [25, 26]. This database address is
This is a variant-related database that collates already known gene lesion that is responsible for human inherited diseases. The database includes precision medicine data such as gene symbol, genomics coordinates, splicing, different disease, phenotype and mutations in the human genome [27, 28]. This database is accessible via
Clinical Genomic Database fills the critical niche in the field of clinical and genomic medicine; it also encompasses medically significant genetic data with available interventions. For each entry in the database, the CGD gives out data such as allelic conditions, gene symbol, clinical categorization (both manifestation and interventions), affected age groups mode of inheritance and pathogenic mutation for all diseases so far captured [27]. This database can be accessed via
There are other ongoing database projects to improve the existing ones, an example of this is The Human Variome Project [29]. Also, there are many websites and databases linked to precision medicine that this chapter cannot introduce all. Table 1 below provides more of the database related to precision medicine in general and their links [30].
Database | Link |
---|---|
Pathway Interaction Database | |
VirusMINT (interaction between viral protein and human) | |
AutDB (animal model resources) | |
Pathogen Interaction Gateway ((host and pathogen interaction) | |
NetPath (signal transduction) | |
Entrez – (encompasses sub-Databases) | |
GeneCards | |
Human Genome Resources | |
Ensembl Human Genome Browser | |
Online Mendelian Inheritance in Man (OMIM) | |
GeneCards | |
Entrez Gene | |
National Institute of Neurological Disorders and Stroke (NINDS): Clinical and Translational Resources | |
Database of Genotypes and Phenotypes (dbGaP) | |
NIH Chemical Genomics Center | |
Gene Expression Omnibus | |
ENCODE Project: ENCyclopedia of DNA Elements, NHGRI | |
PubChem | |
PhenX Toolkit | |
Human Genome Project, NHGRI | |
NCBI BioSystems | |
National Human Genome Research Institute (NHGRI) | |
Kyoto Encyclopedia of Genes and Genomes | |
HUPO Brain Proteome Project | |
ExPASy Proteomics Server | |
HUPO: Human Proteome Organization | |
European Proteomics Association (EuPA) |
Database linked to precision medicine in general and their links [30].
Data sharing is the potential inherent in the exchange of the same data resource with many applications or users; it encompasses the transferring of copies, accessing and enabling the reuse of data. Data can be open access (publicly available) or controlled (restricted), also, sharing data encompasses both sharing of primary (in case of nucleotide sequences) and secondary data (already used or analyzed data) [31].
Figure 4 above illustrates that precision medicine data encompasses both hospital data (information), GIS and PGHD. Sharing of the Precision medicine information (clinical data) can be accessed openly or otherwise restricted, whereby authorization will be needed by an authorized person to access and use the specified data for therapeutic, diagnostic and research purpose.
Semantic diagram of genomic and personalized medicine data sharing (LIS: Laboratory Information System; GIS: Genome Information System; EHR: Electronic Health Record; PGHD: Person Generated Health Data; PACS: Picture Archives and Communication System; CPOE: Computerized Physician Order Entry).
Autoimmune diseases are disease conditions where the immune system respond to self-antigens as a result of damage or dysfunction or disorder in the tissues. It is controlled by a whole lot of factors of which host gene and environment play a vital role. It could affect the entire body, selected systems or selected organs and an interplay between genetic makeup with environmental factors and the self-antigen presented for recognition controls which organ or system of the body that will become the target of the immune system [32, 33].
The precision medicines of the following autoimmune diseases are discussed below:
Multiple Sclerosis
Myasthenia Gravis
Pernicious Anemia
Rheumatoid Arthritis
Sjogren Syndrome
Lupus Erythematosus
Type 1 Diabetes
Multiple sclerosis is an inflammatory/autoimmune disorder that selects the myelin in the central nervous system which is capable of affecting patients of all age and causing neurologic disability when not adequately managed [34, 35]. More than 200 loci have been identified as an independent contributor to the pathogenesis of multiple sclerosis [36]. Multiple sclerosis is usually diagnosed between age 30 and 50 in most patients and occurs more often in females than male. The best way to understand the pathogenesis of multiple sclerosis is to address it from a multifactorial perspective with a model that proposes the interaction among genetic, epigenetic, infectious, dietary, climatic, or other environmental effects, together with sunlight exposure, and smoking. These interacting factors leads to self-intolerance and depreciation of immune homeostasis in the central Nervous system [34]. The brain and spinal cord tissues get infiltrated by stimulating peripheral mononuclear cells, and this leads to the loss of myelin, gliosis, which often leads to neurological dysfunction. Two primary approach of treatment has been given to the patient with multiple sclerosis due to the autoimmune model of the pathogenesis of such disease [34]. The former treatment is the use of global immunosuppressive agents which are aggressive. At the same time, the latter is the use of more specific agents to target specific elements of the immune system.
The contribution of common variants to multiple sclerosis has been probed, and different HLA alleles variants have been modeled for their contribution to multiple sclerosis and were found to be almost as common in control as it is in the sample as it was observed that OR of the statistical analysis tends towards 1 with an increase in sample size [37]. Biomarkers are important in the genetic assessment of Multiple Sclerosis as they possess the ability to express diverse aspects of multiple sclerosis heterogeneity. They also help in the diagnosis, stratification, and disease course prediction, identification of beneficial therapies and development of a precise treatment based on the predicted treatment response. As of 2016, MRI has turned to the most appropriate tool in the diagnosis of MS. The recommendation for brain MRI is the use of 1.5 T field strength, but 3.0 T is deemed preferable. However, using 7 T field strength has been supported by recent evidence to detect central vein in brain lesion of MS patients, but this can also be depicted using T2-weighted sequences at 3 T which help in the differentiation from microangiopathic lesions. The use of MRI for the diagnosis of MS seems simplified but its complexity sets in the differentiation of MS from other disease conditions like neuromyelitis optical spectrum disorders (NMOSD) which also has short spinal cord lesion at the onset. T2-weighted and contrast-enhanced T1-weighted brain MRI are recommended for the monitoring of disease progression while MRI of the spinal cord is not encouraged. Other than the MRI biomarkers there exist a few body fluid biomarker which could mark different stages of MS disease and differentiate each step from other similar disease conditions [34].
Body fluid biomarkers can be divided into three main groups, including those marking the early phase of MS, those associated with disease course and those associated with treatment response. Low vitamin D level in Cerebrospinal fluid is a marker of the initial stage of MS. Astrocyte-derived chitinase 3-like 1 (CHI3L1) in the CSF is also a prognostic marker of which an increased level of CHI3L1 in the CSF is a significant independent risk factor connected with the progression of disability in multivariate Cox regression models. Utilizing a proteomic approach and verification of result with ELISA confirmed that CHI3L1 would be the best predictors of the conversion to MS in CIS patients. CSF CHI3L1 level with MRI and age were the best predictors of MS risk in a multivariable analysis. Neurofilaments (NF-L) has also been implicated as a biomarker in the early phase of MS [36, 37].
Transcriptional regulator high-mobility group box protein 1 help differentiates patients with relapse-onset MS from patients from primary progressive MS. Proteomic studies show that two isoforms of vitamin D-binding protein and apolipoprotein E permit discrimination between MS patients with aggressive and benign disease courses [36]. During the disease course, calcium-binding protein secretogranin-1 is decreased in the CSF when compared with the early phase of MS. Stable MS patients, when compared with relapsing patients, possess an increase in B cell activating factors in their plasma samples. Solute carrier family 9, subfamily A (SLC9A9) is a biomarker associated with the non-response to IFN beta. Upregulation of the NLR family, pyrin domain containing 3 (NLRP3) inflammasome is also a biomarker for non-responsive IFN beta treatment. Biomarkers of glatiramer acetate response are feedback gene to complement 32 (RGC-32), FasL, and IL-21. Up-regulated mRNA expression levels of RGC-32 and FasL and reduced expression of IL-21 seen in peripheral blood cells from responders in contrast to non-responders forms the basis for the use of these biomarkers [34, 36, 37].
Myasthenia gravis (MG) is an autoimmune disease treated with chronic immunosuppression due to the actions of autoantibodies against the diverse structure of the neuromuscular intersection [38]. The variation of the patient’s response to treatment and the variation in side effects to such treatment is the justifying reason for the recognition of the biological markers to predict the effectiveness of each treatment in each patient. Presence of anti-AChR antibodies is a beneficial biomarker in the diagnosis of MG. Still, it cannot judge disease severity as no specific correlation was found between MG severity and anti-AChR antibodies level [39]. MiR-323b-3p, −409-3p, −485-3p, −181d-5p, and − 340-3p has been predicted and suggested as response biomarker to project immunosuppressive drug sensitivity in MG patients.
The miRNAs can be tested in the blood, which would make it a potent response biomarker for treatment response, and any patient detected not to respond as expected will be addressed to other treatments thereby increasing cost-effectiveness. MiR-323b-3p, −409-3p and − 485-3p were downregulated in Non-responding patients while miRNA-181d-5p, and − 340-3p were upregulated in the Non-responding patients [39, 40]. A significant association has been identified between patient’s response to azathioprine and two haplotypes, the TPMT3E haplotype in the thiopurine S-methyltransferase and a haplotype in the ATP-binding cassette sub-family C member 6 transporter. The glucocorticoid therapy non-responsive MG patients were found to possess a genetic variant in the secreted phosphoprotein 1 (SPP1) gene encoding osteopontin, which associates it with the non-responsive group [40].
Pernicious anemia (PA), is an autoimmune disease which results from a long-standing infection by Helicobacter pylori and the end-stage of atrophic body gastritis (ABG). The condition which is still active gradually phased out by an autoimmunity reaction that depletes the gastric mucosa irreversibly. The deficiency of vitamin B12 has been implicated in the etiology also. Therefore the goal of a clinician in treating pernicious anemia may be to avert the signs and symptoms of anemia itself, manage its complications such as damage to the nerve and heart tissues, and identifying the specific cause where precision medicine comes in [41]. The National Heart, Lung, and Blood Institute (NHLBI) are currently carrying out basic and clinical researches that could incorporate precision medicine and improve the treatment of the condition.
Rheumatoid arthritis (RA) is a heterogeneous disease which can range from mild, self-limiting arthritis to fast progressive joint damage. It is triggered by a complex interaction between the human genetic makeup and the environment. Still, both environmental influence and genetics cannot exhaustively account for the heterogenic clinical features of the disease condition. It is also characterized by synovial hyperplasia and joint destruction, which can lead to joint deformity or [42].
Currently, the treatment of RA is based on the control of inflammation with which an effective therapy that comes early ensures a drastic reduction in the risk of joint damage, mortality and disability. As of 2017, major researches has focused on the identification of biomarkers that can predict patient’s response to only Methotrexate (MTX) which is the first non-biologic therapeutic agent administered. Also, TNF inhibitors (TNFi) has been established to be ineffective in about 30% of patients but remains the first choice of available biologic therapeutic agents. Solute carrier family 19 member 1 (SLC19A1) gene possess the most consistent and relevant evidence. It is one of the many transport carriers that allow the transport of MTX into the cell [43].
Anti- CCP antibodies a genomic marker associated with poor prognosis as it relates to the severity of disease and the extent of damage caused on the joint, HLA-DRB1 alleles coding for shared epitope is another marker for severity in RA [44].
Sjögren’s syndrome (SS) is a form of B cell hypersensitivity which is manifested in the formation of excess autoantibodies and a strong propensity for NHL of B cell emergence [45]. About 5% of patients of primary SS are at risk of lymphoma development. However, it is vital to have a specific biomarker to identify such patient early to be able to monitor and detect early and select appropriate therapy. The diagnostic biomarkers will guide in the diagnosis, and the predictive biomarkers are meant to show another aspect of clinical decision. Cytopenias is an established prognostic biomarker for the development of lymphoma [46]. A lot of proposed biomarkers in the assessment of SS are yet to be confirmed in more extensive studies before adoption into clinical use [47].
The systemic lupus erythematosus (SLE) has a broad spectrum of signs and symptoms which varies among patients and involves numerous organs with skin, joints, kidneys, lungs and CNS included. It is a chronic inflammatory autoimmune disease [48]. An association has been established between SLE and human leukocyte antigen (HLA) haplotypes (HLA-DR3; DR9; DR15; DQA1*0101 especially). The extensive association has also been found between vitamin D matching up with serum concentrations and vitamin D-receptor genomic binding domains [49].
The type 1 diabetes (T1D) takes place as a result of autoimmune beta-cell destruction, which leads to insufficient production of insulin and results in hyperglycemia [50]. Although the role of precision medicine in type 1 diabetes is not well defined, patient with T1D severity varies with difference in their pancreatic autoantibodies profile and the rate at which their beta cells destroy [51].
In genetic studies (an important feature of precision medicine), identification of over 50 genetic signals in notably HLA region has been found to influence T1D predisposition [52]. The diagnostic biomarkers (serum biomarkers) use in the diagnosis of T1D includes the combination of glucose, C-peptide, glycated molecules and autoantibodies established for T1D. Still, these molecules often mark the late stage of the disease [53].
So far, advance in genomic research introduces the administration of islet autoantigens or peptides into a recipient with the risk of T1D; these studies suggest promising changes in immune regulation of islet autoimmunity. The challenges remain dosing frequency, dosage, route of administration, and adjuvants use.
A systemic follow up of variant genes like the TNFRSF1A that is connected with multiple sclerosis risk should be closely investigated by researchers. This gene could give an essential perception of the etiology of multiple sclerosis and new treatment strategies.
Myasthenia gravis-related loci may display their involvement in the pathogenesis of immune disease by increasing immune response, repression of the mechanism involved in immune suppression, alteration of procedure that differentiates between autologous and heterologous molecular configuration through immune tolerance, therefore investigations into Single nucleotide polymorphisms (SNPs) in the general population that is associated with Myasthenia gravis will improve diagnosis, therapy and its outcome.
Genome editing technologies have been used with a degree of success in the treatment of sickle cell disease and β-thalassemia, this could be introduced into the precise treatment of pernicious anemia with proper study of the gene encoding for mitochondrial transport of vitamin B12.
Rheumatoid arthritis research should focus on discovering more associated genes and their resultant effects. Transcriptomic and epigenomic strategies should also be used in discovering biomarkers of response to treatments and pathways that are related to therapies. Integration of genetic, clinical and environmental data are also crucial in achieving the aim of precision medicine in the treatment of rheumatoid arthritis.
Selection of novel treatments could be achieved for sjogren syndrome by identification of genetic risk factors like that of profound interferon signaling pathway by IRF5 and STAT 4 genes.
Prevention of systemic lupus erythematosus by assaying genetic profile, developing new biomarkers of immune activation and alteration is the precise future treatment of this condition.
Investigations into genes and pathways of type 1 diabetes may reveal on time the pathogenic role of the destruction of β-cell and production of clinical disease by the innate and adaptive immune system. Type 1 Diabetes Genetics Consortium (T1DGC) international have resources that could help in diagnosis, interventions, and monitoring outcomes of treatment of type 1 diabetes.
As the era of ‘Big Health Data’ continues, it is essential for the diagnosis, prognosis and treatment monitoring efforts on autoimmune diseases to take advantage of the data and different machine learning and deep learning algorithms to establish patterns and clusters within the disease groups. This will help in the identification of more relevant biomarkers and also help in the easy transition of biomarker researches to the bedside.
Indeed, the application of precision medicine in autoimmune diseases depends on the progress of next-generation sequencing program, which at the same time will strive to provide not only a whole-exome, or transcriptome, but at an exact process that is cost-efficient.
The information provided by the Genomics data is an indispensable component of precision medicine as it holds the key to the explanation in individual variability and evolution [54]. But, the clinical use of genomic data still needs to be improved on to overcome challenges stated by Kim et al. [55] like:
The incongruity between the form of genomic and clinical information: as a result of extensive (several tens of gigabytes of sequence) data in the genomic data, clinical data cannot be processed in the clinical practice without additional processing [55, 56].
The difference in the properties of genomic data and observational data used in the clinical settings: given that the genomic workflows hold a large number of data, data obtained from this workflows is undoubtedly different from systems parallel to the clinical plan [57].
Difficulty in mapping the genomic and clinical data for medical interpretation: as seen in the case of targeted sequencing, where most data are processed before medical analysis [58].
Also, there is no international validation for biomarkers in use; there is a need for international collaboration to validate biomarkers presently in existence.
Overcoming these challenges will open up more opportunities for the use of genomic data in clinical practices.
The authors declare no conflict of interest.
IntechOpen implements a robust policy to minimize and deal with instances of fraud or misconduct. As part of our general commitment to transparency and openness, and in order to maintain high scientific standards, we have a well-defined editorial policy regarding Retractions and Corrections.
",metaTitle:"Retraction and Correction Policy",metaDescription:"Retraction and Correction Policy",metaKeywords:null,canonicalURL:"/page/retraction-and-correction-policy",contentRaw:'[{"type":"htmlEditorComponent","content":"IntechOpen’s Retraction and Correction Policy has been developed in accordance with the Committee on Publication Ethics (COPE) publication guidelines relating to scientific misconduct and research ethics:
\\n\\n1. RETRACTIONS
\\n\\nA Retraction of a Chapter will be issued by the Academic Editor, either following an Author’s request to do so or when there is a 3rd party report of scientific misconduct. Upon receipt of a report by a 3rd party, the Academic Editor will investigate any allegations of scientific misconduct, working in cooperation with the Author(s) and their institution(s).
\\n\\nA formal Retraction will be issued when there is clear and conclusive evidence of any of the following:
\\n\\nPublishing of a Retraction Notice will adhere to the following guidelines:
\\n\\n1.2. REMOVALS AND CANCELLATIONS
\\n\\n2. STATEMENTS OF CONCERN
\\n\\nA Statement of Concern detailing alleged misconduct will be issued by the Academic Editor or publisher following a 3rd party report of scientific misconduct when:
\\n\\nIntechOpen believes that the number of occasions on which a Statement of Concern is issued will be very few in number. In all cases when such a decision has been taken by the Academic Editor the decision will be reviewed by another editor to whom the author can make representations.
\\n\\n3. CORRECTIONS
\\n\\nA Correction will be issued by the Academic Editor when:
\\n\\n3.1. ERRATUM
\\n\\nAn Erratum will be issued by the Academic Editor when it is determined that a mistake in a Chapter originates from the production process handled by the publisher.
\\n\\nA published Erratum will adhere to the Retraction Notice publishing guidelines outlined above.
\\n\\n3.2. CORRIGENDUM
\\n\\nA Corrigendum will be issued by the Academic Editor when it is determined that a mistake in a Chapter is a result of an Author’s miscalculation or oversight. A published Corrigendum will adhere to the Retraction Notice publishing guidelines outlined above.
\\n\\n4. FINAL REMARKS
\\n\\nIntechOpen wishes to emphasize that the final decision on whether a Retraction, Statement of Concern, or a Correction will be issued rests with the Academic Editor. The publisher is obliged to act upon any reports of scientific misconduct in its publications and to make a reasonable effort to facilitate any subsequent investigation of such claims.
\\n\\nIn the case of Retraction or removal of the Work, the publisher will be under no obligation to refund the APC.
\\n\\nThe general principles set out above apply to Retractions and Corrections issued in all IntechOpen publications.
\\n\\nAny suggestions or comments on this Policy are welcome and may be sent to permissions@intechopen.com.
\\n\\nPolicy last updated: 2017-09-11
\\n"}]'},components:[{type:"htmlEditorComponent",content:'IntechOpen’s Retraction and Correction Policy has been developed in accordance with the Committee on Publication Ethics (COPE) publication guidelines relating to scientific misconduct and research ethics:
\n\n1. RETRACTIONS
\n\nA Retraction of a Chapter will be issued by the Academic Editor, either following an Author’s request to do so or when there is a 3rd party report of scientific misconduct. Upon receipt of a report by a 3rd party, the Academic Editor will investigate any allegations of scientific misconduct, working in cooperation with the Author(s) and their institution(s).
\n\nA formal Retraction will be issued when there is clear and conclusive evidence of any of the following:
\n\nPublishing of a Retraction Notice will adhere to the following guidelines:
\n\n1.2. REMOVALS AND CANCELLATIONS
\n\n2. STATEMENTS OF CONCERN
\n\nA Statement of Concern detailing alleged misconduct will be issued by the Academic Editor or publisher following a 3rd party report of scientific misconduct when:
\n\nIntechOpen believes that the number of occasions on which a Statement of Concern is issued will be very few in number. In all cases when such a decision has been taken by the Academic Editor the decision will be reviewed by another editor to whom the author can make representations.
\n\n3. CORRECTIONS
\n\nA Correction will be issued by the Academic Editor when:
\n\n3.1. ERRATUM
\n\nAn Erratum will be issued by the Academic Editor when it is determined that a mistake in a Chapter originates from the production process handled by the publisher.
\n\nA published Erratum will adhere to the Retraction Notice publishing guidelines outlined above.
\n\n3.2. CORRIGENDUM
\n\nA Corrigendum will be issued by the Academic Editor when it is determined that a mistake in a Chapter is a result of an Author’s miscalculation or oversight. A published Corrigendum will adhere to the Retraction Notice publishing guidelines outlined above.
\n\n4. FINAL REMARKS
\n\nIntechOpen wishes to emphasize that the final decision on whether a Retraction, Statement of Concern, or a Correction will be issued rests with the Academic Editor. The publisher is obliged to act upon any reports of scientific misconduct in its publications and to make a reasonable effort to facilitate any subsequent investigation of such claims.
\n\nIn the case of Retraction or removal of the Work, the publisher will be under no obligation to refund the APC.
\n\nThe general principles set out above apply to Retractions and Corrections issued in all IntechOpen publications.
\n\nAny suggestions or comments on this Policy are welcome and may be sent to permissions@intechopen.com.
\n\nPolicy last updated: 2017-09-11
\n'}]},successStories:{items:[]},authorsAndEditors:{filterParams:{sort:"featured,name"},profiles:[{id:"6700",title:"Dr.",name:"Abbass A.",middleName:null,surname:"Hashim",slug:"abbass-a.-hashim",fullName:"Abbass A. Hashim",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/6700/images/1864_n.jpg",biography:"Currently I am carrying out research in several areas of interest, mainly covering work on chemical and bio-sensors, semiconductor thin film device fabrication and characterisation.\nAt the moment I have very strong interest in radiation environmental pollution and bacteriology treatment. The teams of researchers are working very hard to bring novel results in this field. I am also a member of the team in charge for the supervision of Ph.D. students in the fields of development of silicon based planar waveguide sensor devices, study of inelastic electron tunnelling in planar tunnelling nanostructures for sensing applications and development of organotellurium(IV) compounds for semiconductor applications. I am a specialist in data analysis techniques and nanosurface structure. I have served as the editor for many books, been a member of the editorial board in science journals, have published many papers and hold many patents.",institutionString:null,institution:{name:"Sheffield Hallam University",country:{name:"United Kingdom"}}},{id:"54525",title:"Prof.",name:"Abdul Latif",middleName:null,surname:"Ahmad",slug:"abdul-latif-ahmad",fullName:"Abdul Latif Ahmad",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:null},{id:"20567",title:"Prof.",name:"Ado",middleName:null,surname:"Jorio",slug:"ado-jorio",fullName:"Ado Jorio",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"Universidade Federal de Minas Gerais",country:{name:"Brazil"}}},{id:"47940",title:"Dr.",name:"Alberto",middleName:null,surname:"Mantovani",slug:"alberto-mantovani",fullName:"Alberto Mantovani",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:null},{id:"12392",title:"Mr.",name:"Alex",middleName:null,surname:"Lazinica",slug:"alex-lazinica",fullName:"Alex Lazinica",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/12392/images/7282_n.png",biography:"Alex Lazinica is the founder and CEO of IntechOpen. After obtaining a Master's degree in Mechanical Engineering, he continued his PhD studies in Robotics at the Vienna University of Technology. Here he worked as a robotic researcher with the university's Intelligent Manufacturing Systems Group as well as a guest researcher at various European universities, including the Swiss Federal Institute of Technology Lausanne (EPFL). During this time he published more than 20 scientific papers, gave presentations, served as a reviewer for major robotic journals and conferences and most importantly he co-founded and built the International Journal of Advanced Robotic Systems- world's first Open Access journal in the field of robotics. Starting this journal was a pivotal point in his career, since it was a pathway to founding IntechOpen - Open Access publisher focused on addressing academic researchers needs. Alex is a personification of IntechOpen key values being trusted, open and entrepreneurial. Today his focus is on defining the growth and development strategy for the company.",institutionString:null,institution:{name:"TU Wien",country:{name:"Austria"}}},{id:"19816",title:"Prof.",name:"Alexander",middleName:null,surname:"Kokorin",slug:"alexander-kokorin",fullName:"Alexander Kokorin",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/19816/images/1607_n.jpg",biography:"Alexander I. Kokorin: born: 1947, Moscow; DSc., PhD; Principal Research Fellow (Research Professor) of Department of Kinetics and Catalysis, N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow.\r\nArea of research interests: physical chemistry of complex-organized molecular and nanosized systems, including polymer-metal complexes; the surface of doped oxide semiconductors. He is an expert in structural, absorptive, catalytic and photocatalytic properties, in structural organization and dynamic features of ionic liquids, in magnetic interactions between paramagnetic centers. The author or co-author of 3 books, over 200 articles and reviews in scientific journals and books. He is an actual member of the International EPR/ESR Society, European Society on Quantum Solar Energy Conversion, Moscow House of Scientists, of the Board of Moscow Physical Society.",institutionString:null,institution:{name:"Semenov Institute of Chemical Physics",country:{name:"Russia"}}},{id:"62389",title:"PhD.",name:"Ali Demir",middleName:null,surname:"Sezer",slug:"ali-demir-sezer",fullName:"Ali Demir Sezer",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/62389/images/3413_n.jpg",biography:"Dr. Ali Demir Sezer has a Ph.D. from Pharmaceutical Biotechnology at the Faculty of Pharmacy, University of Marmara (Turkey). He is the member of many Pharmaceutical Associations and acts as a reviewer of scientific journals and European projects under different research areas such as: drug delivery systems, nanotechnology and pharmaceutical biotechnology. Dr. Sezer is the author of many scientific publications in peer-reviewed journals and poster communications. Focus of his research activity is drug delivery, physico-chemical characterization and biological evaluation of biopolymers micro and nanoparticles as modified drug delivery system, and colloidal drug carriers (liposomes, nanoparticles etc.).",institutionString:null,institution:{name:"Marmara University",country:{name:"Turkey"}}},{id:"61051",title:"Prof.",name:"Andrea",middleName:null,surname:"Natale",slug:"andrea-natale",fullName:"Andrea Natale",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:null},{id:"100762",title:"Prof.",name:"Andrea",middleName:null,surname:"Natale",slug:"andrea-natale",fullName:"Andrea Natale",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"St David's Medical Center",country:{name:"United States of America"}}},{id:"107416",title:"Dr.",name:"Andrea",middleName:null,surname:"Natale",slug:"andrea-natale",fullName:"Andrea Natale",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"Texas Cardiac Arrhythmia",country:{name:"United States of America"}}},{id:"64434",title:"Dr.",name:"Angkoon",middleName:null,surname:"Phinyomark",slug:"angkoon-phinyomark",fullName:"Angkoon Phinyomark",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/64434/images/2619_n.jpg",biography:"My name is Angkoon Phinyomark. I received a B.Eng. degree in Computer Engineering with First Class Honors in 2008 from Prince of Songkla University, Songkhla, Thailand, where I received a Ph.D. degree in Electrical Engineering. My research interests are primarily in the area of biomedical signal processing and classification notably EMG (electromyography signal), EOG (electrooculography signal), and EEG (electroencephalography signal), image analysis notably breast cancer analysis and optical coherence tomography, and rehabilitation engineering. I became a student member of IEEE in 2008. During October 2011-March 2012, I had worked at School of Computer Science and Electronic Engineering, University of Essex, Colchester, Essex, United Kingdom. In addition, during a B.Eng. I had been a visiting research student at Faculty of Computer Science, University of Murcia, Murcia, Spain for three months.\n\nI have published over 40 papers during 5 years in refereed journals, books, and conference proceedings in the areas of electro-physiological signals processing and classification, notably EMG and EOG signals, fractal analysis, wavelet analysis, texture analysis, feature extraction and machine learning algorithms, and assistive and rehabilitative devices. I have several computer programming language certificates, i.e. Sun Certified Programmer for the Java 2 Platform 1.4 (SCJP), Microsoft Certified Professional Developer, Web Developer (MCPD), Microsoft Certified Technology Specialist, .NET Framework 2.0 Web (MCTS). I am a Reviewer for several refereed journals and international conferences, such as IEEE Transactions on Biomedical Engineering, IEEE Transactions on Industrial Electronics, Optic Letters, Measurement Science Review, and also a member of the International Advisory Committee for 2012 IEEE Business Engineering and Industrial Applications and 2012 IEEE Symposium on Business, Engineering and Industrial Applications.",institutionString:null,institution:{name:"Joseph Fourier University",country:{name:"France"}}},{id:"55578",title:"Dr.",name:"Antonio",middleName:null,surname:"Jurado-Navas",slug:"antonio-jurado-navas",fullName:"Antonio Jurado-Navas",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/55578/images/4574_n.png",biography:"Antonio Jurado-Navas received the M.S. degree (2002) and the Ph.D. degree (2009) in Telecommunication Engineering, both from the University of Málaga (Spain). He first worked as a consultant at Vodafone-Spain. From 2004 to 2011, he was a Research Assistant with the Communications Engineering Department at the University of Málaga. In 2011, he became an Assistant Professor in the same department. From 2012 to 2015, he was with Ericsson Spain, where he was working on geo-location\ntools for third generation mobile networks. Since 2015, he is a Marie-Curie fellow at the Denmark Technical University. His current research interests include the areas of mobile communication systems and channel modeling in addition to atmospheric optical communications, adaptive optics and statistics",institutionString:null,institution:{name:"University of Malaga",country:{name:"Spain"}}}],filtersByRegion:[{group:"region",caption:"North America",value:1,count:5775},{group:"region",caption:"Middle and South America",value:2,count:5238},{group:"region",caption:"Africa",value:3,count:1721},{group:"region",caption:"Asia",value:4,count:10409},{group:"region",caption:"Australia and Oceania",value:5,count:897},{group:"region",caption:"Europe",value:6,count:15805}],offset:12,limit:12,total:118374},chapterEmbeded:{data:{}},editorApplication:{success:null,errors:{}},ofsBooks:{filterParams:{topicId:"10"},books:[{type:"book",id:"8969",title:"Deserts and Desertification",subtitle:null,isOpenForSubmission:!0,hash:"4df95c7f295de7f6003e635d9a309fe9",slug:null,bookSignature:"Dr. Yajuan Zhu, Dr. Qinghong Luo and Dr. Yuguo Liu",coverURL:"https://cdn.intechopen.com/books/images_new/8969.jpg",editedByType:null,editors:[{id:"180427",title:"Dr.",name:"Yajuan",surname:"Zhu",slug:"yajuan-zhu",fullName:"Yajuan Zhu"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10754",title:"Global Warming and Climate Change",subtitle:null,isOpenForSubmission:!0,hash:"8994a915a306910a01cbe2027aa2139b",slug:null,bookSignature:"Dr. Stuart Arthur Harris",coverURL:"https://cdn.intechopen.com/books/images_new/10754.jpg",editedByType:null,editors:[{id:"12539",title:"Dr.",name:"Stuart",surname:"Harris",slug:"stuart-harris",fullName:"Stuart Harris"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10756",title:"Urban Agglomeration",subtitle:null,isOpenForSubmission:!0,hash:"65f2a1fef9c804c29b18ef3ac4a35066",slug:null,bookSignature:"Dr. Luis Loures",coverURL:"https://cdn.intechopen.com/books/images_new/10756.jpg",editedByType:null,editors:[{id:"108118",title:"Dr.",name:"Luis",surname:"Loures",slug:"luis-loures",fullName:"Luis Loures"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10761",title:"Glaciology",subtitle:null,isOpenForSubmission:!0,hash:"bd112c839a9b8037f1302ca6c0d55a2a",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/10761.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10762",title:"Cosmology",subtitle:null,isOpenForSubmission:!0,hash:"f28a2213571fb878839bcbacb9827a1d",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/10762.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10851",title:"Volcanology",subtitle:null,isOpenForSubmission:!0,hash:"6cfc09f959efecf9ba95654b1bb4b987",slug:null,bookSignature:"Prof. Angelo Paone and Prof. Sung-Hyo Yun",coverURL:"https://cdn.intechopen.com/books/images_new/10851.jpg",editedByType:null,editors:[{id:"182871",title:"Prof.",name:"Angelo",surname:"Paone",slug:"angelo-paone",fullName:"Angelo Paone"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10949",title:"Clay and Clay Minerals",subtitle:null,isOpenForSubmission:!0,hash:"44d08b9e490617fcbf7786c381c85fbc",slug:null,bookSignature:"Prof. Gustavo Morari Do Nascimento",coverURL:"https://cdn.intechopen.com/books/images_new/10949.jpg",editedByType:null,editors:[{id:"7153",title:"Prof.",name:"Gustavo",surname:"Morari Do Nascimento",slug:"gustavo-morari-do-nascimento",fullName:"Gustavo Morari Do Nascimento"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10950",title:"Landslides",subtitle:null,isOpenForSubmission:!0,hash:"8fcc0f63c22c087239f07a8e06ec2549",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/10950.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10952",title:"Soil Science - Emerging Technologies, Global Perspectives and Applications",subtitle:null,isOpenForSubmission:!0,hash:"3dbedd2099c57a24eaab114be4ba2b48",slug:null,bookSignature:"Dr. Michael Thomas Aide and Dr. Indi Braden",coverURL:"https://cdn.intechopen.com/books/images_new/10952.jpg",editedByType:null,editors:[{id:"185895",title:"Dr.",name:"Michael",surname:"Aide",slug:"michael-aide",fullName:"Michael Aide"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10954",title:"Dark Matter - Recent Observations and Theoretical Advances",subtitle:null,isOpenForSubmission:!0,hash:"b0fbd6ee0096e4c16e9513bf01273ab3",slug:null,bookSignature:"Dr. Michael L. Smith",coverURL:"https://cdn.intechopen.com/books/images_new/10954.jpg",editedByType:null,editors:[{id:"59479",title:"Dr.",name:"Michael L.",surname:"Smith",slug:"michael-l.-smith",fullName:"Michael L. Smith"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}],filtersByTopic:[{group:"topic",caption:"Agricultural and Biological Sciences",value:5,count:18},{group:"topic",caption:"Biochemistry, Genetics and Molecular Biology",value:6,count:5},{group:"topic",caption:"Business, Management and Economics",value:7,count:2},{group:"topic",caption:"Chemistry",value:8,count:8},{group:"topic",caption:"Computer and Information Science",value:9,count:5},{group:"topic",caption:"Earth and Planetary Sciences",value:10,count:7},{group:"topic",caption:"Engineering",value:11,count:19},{group:"topic",caption:"Environmental Sciences",value:12,count:2},{group:"topic",caption:"Immunology and Microbiology",value:13,count:3},{group:"topic",caption:"Materials Science",value:14,count:5},{group:"topic",caption:"Mathematics",value:15,count:1},{group:"topic",caption:"Medicine",value:16,count:24},{group:"topic",caption:"Neuroscience",value:18,count:2},{group:"topic",caption:"Pharmacology, Toxicology and Pharmaceutical Science",value:19,count:3},{group:"topic",caption:"Physics",value:20,count:3},{group:"topic",caption:"Psychology",value:21,count:4},{group:"topic",caption:"Robotics",value:22,count:1},{group:"topic",caption:"Social Sciences",value:23,count:3},{group:"topic",caption:"Technology",value:24,count:1},{group:"topic",caption:"Veterinary Medicine and Science",value:25,count:1}],offset:12,limit:12,total:10},popularBooks:{featuredBooks:[{type:"book",id:"9521",title:"Antimicrobial Resistance",subtitle:"A One Health Perspective",isOpenForSubmission:!1,hash:"30949e78832e1afba5606634b52056ab",slug:"antimicrobial-resistance-a-one-health-perspective",bookSignature:"Mihai Mareș, Swee Hua Erin Lim, Kok-Song Lai and Romeo-Teodor Cristina",coverURL:"https://cdn.intechopen.com/books/images_new/9521.jpg",editors:[{id:"88785",title:"Prof.",name:"Mihai",middleName:null,surname:"Mares",slug:"mihai-mares",fullName:"Mihai Mares"}],equalEditorOne:{id:"190224",title:"Dr.",name:"Swee Hua Erin",middleName:null,surname:"Lim",slug:"swee-hua-erin-lim",fullName:"Swee Hua Erin Lim",profilePictureURL:"https://mts.intechopen.com/storage/users/190224/images/system/190224.png",biography:"Dr. Erin Lim is presently working as an Assistant Professor in the Division of Health Sciences, Abu Dhabi Women\\'s College, Higher Colleges of Technology in Abu Dhabi, United Arab Emirates and is affiliated as an Associate Professor to Perdana University-Royal College of Surgeons in Ireland, Selangor, Malaysia. She obtained her Ph.D. from Universiti Putra Malaysia in 2010 with a National Science Fellowship awarded from the Ministry of Science, Technology and Innovation Malaysia and has been actively involved in research ever since. Her main research interests include analysis of carriage and transmission of multidrug resistant bacteria in non-conventional settings, besides an interest in natural products for antimicrobial testing. She is heavily involved in the elucidation of mechanisms of reversal of resistance in bacteria in addition to investigating the immunological analyses of diseases, development of vaccination and treatment models in animals. She hopes her work will support the discovery of therapeutics in the clinical setting and assist in the combat against the burden of antibiotic resistance.",institutionString:"Abu Dhabi Women’s College",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"3",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"Perdana University",institutionURL:null,country:{name:"Malaysia"}}},equalEditorTwo:{id:"221544",title:"Dr.",name:"Kok-Song",middleName:null,surname:"Lai",slug:"kok-song-lai",fullName:"Kok-Song Lai",profilePictureURL:"https://mts.intechopen.com/storage/users/221544/images/system/221544.jpeg",biography:"Dr. Lai Kok Song is an Assistant Professor in the Division of Health Sciences, Abu Dhabi Women\\'s College, Higher Colleges of Technology in Abu Dhabi, United Arab Emirates. He obtained his Ph.D. in Biological Sciences from Nara Institute of Science and Technology, Japan in 2012. Prior to his academic appointment, Dr. Lai worked as a Senior Scientist at the Ministry of Science, Technology and Innovation, Malaysia. His current research areas include antimicrobial resistance and plant-pathogen interaction. His particular interest lies in the study of the antimicrobial mechanism via membrane disruption of essential oils against multi-drug resistance bacteria through various biochemical, molecular and proteomic approaches. Ultimately, he hopes to uncover and determine novel biomarkers related to antibiotic resistance that can be developed into new therapeutic strategies.",institutionString:"Higher Colleges of Technology",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"8",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"Higher Colleges of Technology",institutionURL:null,country:{name:"United Arab Emirates"}}},equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10020",title:"Operations Management",subtitle:"Emerging Trend in the Digital Era",isOpenForSubmission:!1,hash:"526f0dbdc7e4d85b82ce8383ab894b4c",slug:"operations-management-emerging-trend-in-the-digital-era",bookSignature:"Antonella Petrillo, Fabio De Felice, Germano Lambert-Torres and Erik Bonaldi",coverURL:"https://cdn.intechopen.com/books/images_new/10020.jpg",editors:[{id:"181603",title:"Dr.",name:"Antonella",middleName:null,surname:"Petrillo",slug:"antonella-petrillo",fullName:"Antonella Petrillo"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9560",title:"Creativity",subtitle:"A Force to Innovation",isOpenForSubmission:!1,hash:"58f740bc17807d5d88d647c525857b11",slug:"creativity-a-force-to-innovation",bookSignature:"Pooja Jain",coverURL:"https://cdn.intechopen.com/books/images_new/9560.jpg",editors:[{id:"316765",title:"Dr.",name:"Pooja",middleName:null,surname:"Jain",slug:"pooja-jain",fullName:"Pooja Jain"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10192",title:"Background and Management of Muscular Atrophy",subtitle:null,isOpenForSubmission:!1,hash:"eca24028d89912b5efea56e179dff089",slug:"background-and-management-of-muscular-atrophy",bookSignature:"Julianna Cseri",coverURL:"https://cdn.intechopen.com/books/images_new/10192.jpg",editors:[{id:"135579",title:"Dr.",name:"Julianna",middleName:null,surname:"Cseri",slug:"julianna-cseri",fullName:"Julianna Cseri"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9243",title:"Coastal Environments",subtitle:null,isOpenForSubmission:!1,hash:"8e05e5f631e935eef366980f2e28295d",slug:"coastal-environments",bookSignature:"Yuanzhi Zhang and X. San Liang",coverURL:"https://cdn.intechopen.com/books/images_new/9243.jpg",editors:[{id:"77597",title:"Prof.",name:"Yuanzhi",middleName:null,surname:"Zhang",slug:"yuanzhi-zhang",fullName:"Yuanzhi Zhang"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9385",title:"Renewable Energy",subtitle:"Technologies and Applications",isOpenForSubmission:!1,hash:"a6b446d19166f17f313008e6c056f3d8",slug:"renewable-energy-technologies-and-applications",bookSignature:"Tolga Taner, Archana Tiwari and Taha Selim Ustun",coverURL:"https://cdn.intechopen.com/books/images_new/9385.jpg",editors:[{id:"197240",title:"Associate Prof.",name:"Tolga",middleName:null,surname:"Taner",slug:"tolga-taner",fullName:"Tolga Taner"}],equalEditorOne:{id:"186791",title:"Dr.",name:"Archana",middleName:null,surname:"Tiwari",slug:"archana-tiwari",fullName:"Archana Tiwari",profilePictureURL:"https://mts.intechopen.com/storage/users/186791/images/system/186791.jpg",biography:"Dr. Archana Tiwari is Associate Professor at Amity University, India. Her research interests include renewable sources of energy from microalgae and further utilizing the residual biomass for the generation of value-added products, bioremediation through microalgae and microbial consortium, antioxidative enzymes and stress, and nutraceuticals from microalgae. She has been working on algal biotechnology for the last two decades. She has published her research in many international journals and has authored many books and chapters with renowned publishing houses. She has also delivered talks as an invited speaker at many national and international conferences. Dr. Tiwari is the recipient of several awards including Researcher of the Year and Distinguished Scientist.",institutionString:"Amity University",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"3",totalChapterViews:"0",totalEditedBooks:"1",institution:{name:"Amity University",institutionURL:null,country:{name:"India"}}},equalEditorTwo:{id:"197609",title:"Prof.",name:"Taha Selim",middleName:null,surname:"Ustun",slug:"taha-selim-ustun",fullName:"Taha Selim Ustun",profilePictureURL:"https://mts.intechopen.com/storage/users/197609/images/system/197609.jpeg",biography:"Dr. Taha Selim Ustun received a Ph.D. in Electrical Engineering from Victoria University, Melbourne, Australia. He is a researcher with the Fukushima Renewable Energy Institute, AIST (FREA), where he leads the Smart Grid Cybersecurity Laboratory. Prior to that, he was a faculty member with the School of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA. His current research interests include power systems protection, communication in power networks, distributed generation, microgrids, electric vehicle integration, and cybersecurity in smart grids. He serves on the editorial boards of IEEE Access, IEEE Transactions on Industrial Informatics, Energies, Electronics, Electricity, World Electric Vehicle and Information journals. Dr. Ustun is a member of the IEEE 2004 and 2800, IEC Renewable Energy Management WG 8, and IEC TC 57 WG17. He has been invited to run specialist courses in Africa, India, and China. He has delivered talks for the Qatar Foundation, the World Energy Council, the Waterloo Global Science Initiative, and the European Union Energy Initiative (EUEI). His research has attracted funding from prestigious programs in Japan, Australia, the European Union, and North America.",institutionString:"Fukushima Renewable Energy Institute, AIST (FREA)",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"1",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"National Institute of Advanced Industrial Science and Technology",institutionURL:null,country:{name:"Japan"}}},equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8985",title:"Natural Resources Management and Biological Sciences",subtitle:null,isOpenForSubmission:!1,hash:"5c2e219a6c021a40b5a20c041dea88c4",slug:"natural-resources-management-and-biological-sciences",bookSignature:"Edward R. Rhodes and Humood Naser",coverURL:"https://cdn.intechopen.com/books/images_new/8985.jpg",editors:[{id:"280886",title:"Prof.",name:"Edward R",middleName:null,surname:"Rhodes",slug:"edward-r-rhodes",fullName:"Edward R Rhodes"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10065",title:"Wavelet Theory",subtitle:null,isOpenForSubmission:!1,hash:"d8868e332169597ba2182d9b004d60de",slug:"wavelet-theory",bookSignature:"Somayeh Mohammady",coverURL:"https://cdn.intechopen.com/books/images_new/10065.jpg",editors:[{id:"109280",title:"Dr.",name:"Somayeh",middleName:null,surname:"Mohammady",slug:"somayeh-mohammady",fullName:"Somayeh Mohammady"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9644",title:"Glaciers and the Polar Environment",subtitle:null,isOpenForSubmission:!1,hash:"e8cfdc161794e3753ced54e6ff30873b",slug:"glaciers-and-the-polar-environment",bookSignature:"Masaki Kanao, Danilo Godone and Niccolò Dematteis",coverURL:"https://cdn.intechopen.com/books/images_new/9644.jpg",editors:[{id:"51959",title:"Dr.",name:"Masaki",middleName:null,surname:"Kanao",slug:"masaki-kanao",fullName:"Masaki Kanao"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9550",title:"Entrepreneurship",subtitle:"Contemporary Issues",isOpenForSubmission:!1,hash:"9b4ac1ee5b743abf6f88495452b1e5e7",slug:"entrepreneurship-contemporary-issues",bookSignature:"Mladen Turuk",coverURL:"https://cdn.intechopen.com/books/images_new/9550.jpg",editors:[{id:"319755",title:"Prof.",name:"Mladen",middleName:null,surname:"Turuk",slug:"mladen-turuk",fullName:"Mladen Turuk"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9027",title:"Human Blood Group Systems and Haemoglobinopathies",subtitle:null,isOpenForSubmission:!1,hash:"d00d8e40b11cfb2547d1122866531c7e",slug:"human-blood-group-systems-and-haemoglobinopathies",bookSignature:"Osaro Erhabor and Anjana Munshi",coverURL:"https://cdn.intechopen.com/books/images_new/9027.jpg",editors:[{id:"35140",title:null,name:"Osaro",middleName:null,surname:"Erhabor",slug:"osaro-erhabor",fullName:"Osaro Erhabor"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8558",title:"Aerodynamics",subtitle:null,isOpenForSubmission:!1,hash:"db7263fc198dfb539073ba0260a7f1aa",slug:"aerodynamics",bookSignature:"Mofid Gorji-Bandpy and Aly-Mousaad Aly",coverURL:"https://cdn.intechopen.com/books/images_new/8558.jpg",editors:[{id:"35542",title:"Prof.",name:"Mofid",middleName:null,surname:"Gorji-Bandpy",slug:"mofid-gorji-bandpy",fullName:"Mofid Gorji-Bandpy"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}}],offset:12,limit:12,total:5247},hotBookTopics:{hotBooks:[],offset:0,limit:12,total:null},publish:{},publishingProposal:{success:null,errors:{}},books:{featuredBooks:[{type:"book",id:"9521",title:"Antimicrobial Resistance",subtitle:"A One Health Perspective",isOpenForSubmission:!1,hash:"30949e78832e1afba5606634b52056ab",slug:"antimicrobial-resistance-a-one-health-perspective",bookSignature:"Mihai Mareș, Swee Hua Erin Lim, Kok-Song Lai and Romeo-Teodor Cristina",coverURL:"https://cdn.intechopen.com/books/images_new/9521.jpg",editors:[{id:"88785",title:"Prof.",name:"Mihai",middleName:null,surname:"Mares",slug:"mihai-mares",fullName:"Mihai Mares"}],equalEditorOne:{id:"190224",title:"Dr.",name:"Swee Hua Erin",middleName:null,surname:"Lim",slug:"swee-hua-erin-lim",fullName:"Swee Hua Erin Lim",profilePictureURL:"https://mts.intechopen.com/storage/users/190224/images/system/190224.png",biography:"Dr. Erin Lim is presently working as an Assistant Professor in the Division of Health Sciences, Abu Dhabi Women\\'s College, Higher Colleges of Technology in Abu Dhabi, United Arab Emirates and is affiliated as an Associate Professor to Perdana University-Royal College of Surgeons in Ireland, Selangor, Malaysia. She obtained her Ph.D. from Universiti Putra Malaysia in 2010 with a National Science Fellowship awarded from the Ministry of Science, Technology and Innovation Malaysia and has been actively involved in research ever since. Her main research interests include analysis of carriage and transmission of multidrug resistant bacteria in non-conventional settings, besides an interest in natural products for antimicrobial testing. She is heavily involved in the elucidation of mechanisms of reversal of resistance in bacteria in addition to investigating the immunological analyses of diseases, development of vaccination and treatment models in animals. She hopes her work will support the discovery of therapeutics in the clinical setting and assist in the combat against the burden of antibiotic resistance.",institutionString:"Abu Dhabi Women’s College",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"3",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"Perdana University",institutionURL:null,country:{name:"Malaysia"}}},equalEditorTwo:{id:"221544",title:"Dr.",name:"Kok-Song",middleName:null,surname:"Lai",slug:"kok-song-lai",fullName:"Kok-Song Lai",profilePictureURL:"https://mts.intechopen.com/storage/users/221544/images/system/221544.jpeg",biography:"Dr. Lai Kok Song is an Assistant Professor in the Division of Health Sciences, Abu Dhabi Women\\'s College, Higher Colleges of Technology in Abu Dhabi, United Arab Emirates. He obtained his Ph.D. in Biological Sciences from Nara Institute of Science and Technology, Japan in 2012. Prior to his academic appointment, Dr. Lai worked as a Senior Scientist at the Ministry of Science, Technology and Innovation, Malaysia. His current research areas include antimicrobial resistance and plant-pathogen interaction. His particular interest lies in the study of the antimicrobial mechanism via membrane disruption of essential oils against multi-drug resistance bacteria through various biochemical, molecular and proteomic approaches. Ultimately, he hopes to uncover and determine novel biomarkers related to antibiotic resistance that can be developed into new therapeutic strategies.",institutionString:"Higher Colleges of Technology",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"8",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"Higher Colleges of Technology",institutionURL:null,country:{name:"United Arab Emirates"}}},equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10020",title:"Operations Management",subtitle:"Emerging Trend in the Digital Era",isOpenForSubmission:!1,hash:"526f0dbdc7e4d85b82ce8383ab894b4c",slug:"operations-management-emerging-trend-in-the-digital-era",bookSignature:"Antonella Petrillo, Fabio De Felice, Germano Lambert-Torres and Erik Bonaldi",coverURL:"https://cdn.intechopen.com/books/images_new/10020.jpg",editors:[{id:"181603",title:"Dr.",name:"Antonella",middleName:null,surname:"Petrillo",slug:"antonella-petrillo",fullName:"Antonella Petrillo"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9560",title:"Creativity",subtitle:"A Force to Innovation",isOpenForSubmission:!1,hash:"58f740bc17807d5d88d647c525857b11",slug:"creativity-a-force-to-innovation",bookSignature:"Pooja Jain",coverURL:"https://cdn.intechopen.com/books/images_new/9560.jpg",editors:[{id:"316765",title:"Dr.",name:"Pooja",middleName:null,surname:"Jain",slug:"pooja-jain",fullName:"Pooja Jain"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10192",title:"Background and Management of Muscular Atrophy",subtitle:null,isOpenForSubmission:!1,hash:"eca24028d89912b5efea56e179dff089",slug:"background-and-management-of-muscular-atrophy",bookSignature:"Julianna Cseri",coverURL:"https://cdn.intechopen.com/books/images_new/10192.jpg",editors:[{id:"135579",title:"Dr.",name:"Julianna",middleName:null,surname:"Cseri",slug:"julianna-cseri",fullName:"Julianna Cseri"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9243",title:"Coastal Environments",subtitle:null,isOpenForSubmission:!1,hash:"8e05e5f631e935eef366980f2e28295d",slug:"coastal-environments",bookSignature:"Yuanzhi Zhang and X. San Liang",coverURL:"https://cdn.intechopen.com/books/images_new/9243.jpg",editors:[{id:"77597",title:"Prof.",name:"Yuanzhi",middleName:null,surname:"Zhang",slug:"yuanzhi-zhang",fullName:"Yuanzhi Zhang"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9385",title:"Renewable Energy",subtitle:"Technologies and Applications",isOpenForSubmission:!1,hash:"a6b446d19166f17f313008e6c056f3d8",slug:"renewable-energy-technologies-and-applications",bookSignature:"Tolga Taner, Archana Tiwari and Taha Selim Ustun",coverURL:"https://cdn.intechopen.com/books/images_new/9385.jpg",editors:[{id:"197240",title:"Associate Prof.",name:"Tolga",middleName:null,surname:"Taner",slug:"tolga-taner",fullName:"Tolga Taner"}],equalEditorOne:{id:"186791",title:"Dr.",name:"Archana",middleName:null,surname:"Tiwari",slug:"archana-tiwari",fullName:"Archana Tiwari",profilePictureURL:"https://mts.intechopen.com/storage/users/186791/images/system/186791.jpg",biography:"Dr. Archana Tiwari is Associate Professor at Amity University, India. Her research interests include renewable sources of energy from microalgae and further utilizing the residual biomass for the generation of value-added products, bioremediation through microalgae and microbial consortium, antioxidative enzymes and stress, and nutraceuticals from microalgae. She has been working on algal biotechnology for the last two decades. She has published her research in many international journals and has authored many books and chapters with renowned publishing houses. She has also delivered talks as an invited speaker at many national and international conferences. Dr. Tiwari is the recipient of several awards including Researcher of the Year and Distinguished Scientist.",institutionString:"Amity University",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"3",totalChapterViews:"0",totalEditedBooks:"1",institution:{name:"Amity University",institutionURL:null,country:{name:"India"}}},equalEditorTwo:{id:"197609",title:"Prof.",name:"Taha Selim",middleName:null,surname:"Ustun",slug:"taha-selim-ustun",fullName:"Taha Selim Ustun",profilePictureURL:"https://mts.intechopen.com/storage/users/197609/images/system/197609.jpeg",biography:"Dr. Taha Selim Ustun received a Ph.D. in Electrical Engineering from Victoria University, Melbourne, Australia. He is a researcher with the Fukushima Renewable Energy Institute, AIST (FREA), where he leads the Smart Grid Cybersecurity Laboratory. Prior to that, he was a faculty member with the School of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA. His current research interests include power systems protection, communication in power networks, distributed generation, microgrids, electric vehicle integration, and cybersecurity in smart grids. He serves on the editorial boards of IEEE Access, IEEE Transactions on Industrial Informatics, Energies, Electronics, Electricity, World Electric Vehicle and Information journals. Dr. Ustun is a member of the IEEE 2004 and 2800, IEC Renewable Energy Management WG 8, and IEC TC 57 WG17. He has been invited to run specialist courses in Africa, India, and China. He has delivered talks for the Qatar Foundation, the World Energy Council, the Waterloo Global Science Initiative, and the European Union Energy Initiative (EUEI). His research has attracted funding from prestigious programs in Japan, Australia, the European Union, and North America.",institutionString:"Fukushima Renewable Energy Institute, AIST (FREA)",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"1",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"National Institute of Advanced Industrial Science and Technology",institutionURL:null,country:{name:"Japan"}}},equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8985",title:"Natural Resources Management and Biological Sciences",subtitle:null,isOpenForSubmission:!1,hash:"5c2e219a6c021a40b5a20c041dea88c4",slug:"natural-resources-management-and-biological-sciences",bookSignature:"Edward R. Rhodes and Humood Naser",coverURL:"https://cdn.intechopen.com/books/images_new/8985.jpg",editors:[{id:"280886",title:"Prof.",name:"Edward R",middleName:null,surname:"Rhodes",slug:"edward-r-rhodes",fullName:"Edward R Rhodes"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10065",title:"Wavelet Theory",subtitle:null,isOpenForSubmission:!1,hash:"d8868e332169597ba2182d9b004d60de",slug:"wavelet-theory",bookSignature:"Somayeh Mohammady",coverURL:"https://cdn.intechopen.com/books/images_new/10065.jpg",editors:[{id:"109280",title:"Dr.",name:"Somayeh",middleName:null,surname:"Mohammady",slug:"somayeh-mohammady",fullName:"Somayeh Mohammady"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9644",title:"Glaciers and the Polar Environment",subtitle:null,isOpenForSubmission:!1,hash:"e8cfdc161794e3753ced54e6ff30873b",slug:"glaciers-and-the-polar-environment",bookSignature:"Masaki Kanao, Danilo Godone and Niccolò Dematteis",coverURL:"https://cdn.intechopen.com/books/images_new/9644.jpg",editors:[{id:"51959",title:"Dr.",name:"Masaki",middleName:null,surname:"Kanao",slug:"masaki-kanao",fullName:"Masaki Kanao"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9550",title:"Entrepreneurship",subtitle:"Contemporary Issues",isOpenForSubmission:!1,hash:"9b4ac1ee5b743abf6f88495452b1e5e7",slug:"entrepreneurship-contemporary-issues",bookSignature:"Mladen Turuk",coverURL:"https://cdn.intechopen.com/books/images_new/9550.jpg",editors:[{id:"319755",title:"Prof.",name:"Mladen",middleName:null,surname:"Turuk",slug:"mladen-turuk",fullName:"Mladen Turuk"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}}],latestBooks:[{type:"book",id:"9243",title:"Coastal Environments",subtitle:null,isOpenForSubmission:!1,hash:"8e05e5f631e935eef366980f2e28295d",slug:"coastal-environments",bookSignature:"Yuanzhi Zhang and X. San Liang",coverURL:"https://cdn.intechopen.com/books/images_new/9243.jpg",editedByType:"Edited by",editors:[{id:"77597",title:"Prof.",name:"Yuanzhi",middleName:null,surname:"Zhang",slug:"yuanzhi-zhang",fullName:"Yuanzhi Zhang"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10020",title:"Operations Management",subtitle:"Emerging Trend in the Digital Era",isOpenForSubmission:!1,hash:"526f0dbdc7e4d85b82ce8383ab894b4c",slug:"operations-management-emerging-trend-in-the-digital-era",bookSignature:"Antonella Petrillo, Fabio De Felice, Germano Lambert-Torres and Erik Bonaldi",coverURL:"https://cdn.intechopen.com/books/images_new/10020.jpg",editedByType:"Edited by",editors:[{id:"181603",title:"Dr.",name:"Antonella",middleName:null,surname:"Petrillo",slug:"antonella-petrillo",fullName:"Antonella Petrillo"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9521",title:"Antimicrobial Resistance",subtitle:"A One Health Perspective",isOpenForSubmission:!1,hash:"30949e78832e1afba5606634b52056ab",slug:"antimicrobial-resistance-a-one-health-perspective",bookSignature:"Mihai Mareș, Swee Hua Erin Lim, Kok-Song Lai and Romeo-Teodor Cristina",coverURL:"https://cdn.intechopen.com/books/images_new/9521.jpg",editedByType:"Edited by",editors:[{id:"88785",title:"Prof.",name:"Mihai",middleName:null,surname:"Mares",slug:"mihai-mares",fullName:"Mihai Mares"}],equalEditorOne:{id:"190224",title:"Dr.",name:"Swee Hua Erin",middleName:null,surname:"Lim",slug:"swee-hua-erin-lim",fullName:"Swee Hua Erin Lim",profilePictureURL:"https://mts.intechopen.com/storage/users/190224/images/system/190224.png",biography:"Dr. Erin Lim is presently working as an Assistant Professor in the Division of Health Sciences, Abu Dhabi Women\\'s College, Higher Colleges of Technology in Abu Dhabi, United Arab Emirates and is affiliated as an Associate Professor to Perdana University-Royal College of Surgeons in Ireland, Selangor, Malaysia. She obtained her Ph.D. from Universiti Putra Malaysia in 2010 with a National Science Fellowship awarded from the Ministry of Science, Technology and Innovation Malaysia and has been actively involved in research ever since. Her main research interests include analysis of carriage and transmission of multidrug resistant bacteria in non-conventional settings, besides an interest in natural products for antimicrobial testing. She is heavily involved in the elucidation of mechanisms of reversal of resistance in bacteria in addition to investigating the immunological analyses of diseases, development of vaccination and treatment models in animals. She hopes her work will support the discovery of therapeutics in the clinical setting and assist in the combat against the burden of antibiotic resistance.",institutionString:"Abu Dhabi Women’s College",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"3",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"Perdana University",institutionURL:null,country:{name:"Malaysia"}}},equalEditorTwo:{id:"221544",title:"Dr.",name:"Kok-Song",middleName:null,surname:"Lai",slug:"kok-song-lai",fullName:"Kok-Song Lai",profilePictureURL:"https://mts.intechopen.com/storage/users/221544/images/system/221544.jpeg",biography:"Dr. Lai Kok Song is an Assistant Professor in the Division of Health Sciences, Abu Dhabi Women\\'s College, Higher Colleges of Technology in Abu Dhabi, United Arab Emirates. He obtained his Ph.D. in Biological Sciences from Nara Institute of Science and Technology, Japan in 2012. Prior to his academic appointment, Dr. Lai worked as a Senior Scientist at the Ministry of Science, Technology and Innovation, Malaysia. His current research areas include antimicrobial resistance and plant-pathogen interaction. His particular interest lies in the study of the antimicrobial mechanism via membrane disruption of essential oils against multi-drug resistance bacteria through various biochemical, molecular and proteomic approaches. Ultimately, he hopes to uncover and determine novel biomarkers related to antibiotic resistance that can be developed into new therapeutic strategies.",institutionString:"Higher Colleges of Technology",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"8",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"Higher Colleges of Technology",institutionURL:null,country:{name:"United Arab Emirates"}}},equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9560",title:"Creativity",subtitle:"A Force to Innovation",isOpenForSubmission:!1,hash:"58f740bc17807d5d88d647c525857b11",slug:"creativity-a-force-to-innovation",bookSignature:"Pooja Jain",coverURL:"https://cdn.intechopen.com/books/images_new/9560.jpg",editedByType:"Edited by",editors:[{id:"316765",title:"Dr.",name:"Pooja",middleName:null,surname:"Jain",slug:"pooja-jain",fullName:"Pooja Jain"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9669",title:"Recent Advances in Rice Research",subtitle:null,isOpenForSubmission:!1,hash:"12b06cc73e89af1e104399321cc16a75",slug:"recent-advances-in-rice-research",bookSignature:"Mahmood-ur- Rahman Ansari",coverURL:"https://cdn.intechopen.com/books/images_new/9669.jpg",editedByType:"Edited by",editors:[{id:"185476",title:"Dr.",name:"Mahmood-Ur-",middleName:null,surname:"Rahman Ansari",slug:"mahmood-ur-rahman-ansari",fullName:"Mahmood-Ur- Rahman Ansari"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10192",title:"Background and Management of Muscular Atrophy",subtitle:null,isOpenForSubmission:!1,hash:"eca24028d89912b5efea56e179dff089",slug:"background-and-management-of-muscular-atrophy",bookSignature:"Julianna Cseri",coverURL:"https://cdn.intechopen.com/books/images_new/10192.jpg",editedByType:"Edited by",editors:[{id:"135579",title:"Dr.",name:"Julianna",middleName:null,surname:"Cseri",slug:"julianna-cseri",fullName:"Julianna Cseri"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9550",title:"Entrepreneurship",subtitle:"Contemporary Issues",isOpenForSubmission:!1,hash:"9b4ac1ee5b743abf6f88495452b1e5e7",slug:"entrepreneurship-contemporary-issues",bookSignature:"Mladen Turuk",coverURL:"https://cdn.intechopen.com/books/images_new/9550.jpg",editedByType:"Edited by",editors:[{id:"319755",title:"Prof.",name:"Mladen",middleName:null,surname:"Turuk",slug:"mladen-turuk",fullName:"Mladen Turuk"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10065",title:"Wavelet Theory",subtitle:null,isOpenForSubmission:!1,hash:"d8868e332169597ba2182d9b004d60de",slug:"wavelet-theory",bookSignature:"Somayeh Mohammady",coverURL:"https://cdn.intechopen.com/books/images_new/10065.jpg",editedByType:"Edited by",editors:[{id:"109280",title:"Dr.",name:"Somayeh",middleName:null,surname:"Mohammady",slug:"somayeh-mohammady",fullName:"Somayeh Mohammady"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9313",title:"Clay Science and Technology",subtitle:null,isOpenForSubmission:!1,hash:"6fa7e70396ff10620e032bb6cfa6fb72",slug:"clay-science-and-technology",bookSignature:"Gustavo Morari Do Nascimento",coverURL:"https://cdn.intechopen.com/books/images_new/9313.jpg",editedByType:"Edited by",editors:[{id:"7153",title:"Prof.",name:"Gustavo",middleName:null,surname:"Morari Do Nascimento",slug:"gustavo-morari-do-nascimento",fullName:"Gustavo Morari Do Nascimento"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9888",title:"Nuclear Power Plants",subtitle:"The Processes from the Cradle to the Grave",isOpenForSubmission:!1,hash:"c2c8773e586f62155ab8221ebb72a849",slug:"nuclear-power-plants-the-processes-from-the-cradle-to-the-grave",bookSignature:"Nasser Awwad",coverURL:"https://cdn.intechopen.com/books/images_new/9888.jpg",editedByType:"Edited by",editors:[{id:"145209",title:"Prof.",name:"Nasser",middleName:"S",surname:"Awwad",slug:"nasser-awwad",fullName:"Nasser Awwad"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}]},subject:{topic:{id:"1049",title:"Mitochondrial Genetics",slug:"mitochondrial-genetics",parent:{title:"Medical Genetics",slug:"medical-genetics"},numberOfBooks:4,numberOfAuthorsAndEditors:136,numberOfWosCitations:36,numberOfCrossrefCitations:35,numberOfDimensionsCitations:68,videoUrl:null,fallbackUrl:null,description:null},booksByTopicFilter:{topicSlug:"mitochondrial-genetics",sort:"-publishedDate",limit:12,offset:0},booksByTopicCollection:[{type:"book",id:"7850",title:"Mitochondria and Brain Disorders",subtitle:null,isOpenForSubmission:!1,hash:"e4cb9b34e45c6177ede9cf78fbda4b82",slug:"mitochondria-and-brain-disorders",bookSignature:"Stavros Baloyannis",coverURL:"https://cdn.intechopen.com/books/images_new/7850.jpg",editedByType:"Edited by",editors:[{id:"156098",title:"Emeritus Prof.",name:"Stavros",middleName:"J",surname:"Baloyannis",slug:"stavros-baloyannis",fullName:"Stavros Baloyannis"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"6684",title:"Mitochondrial DNA",subtitle:"New Insights",isOpenForSubmission:!1,hash:"326a9354db0c23d8a26659e8a0c26872",slug:"mitochondrial-dna-new-insights",bookSignature:"Hervé Seligmann",coverURL:"https://cdn.intechopen.com/books/images_new/6684.jpg",editedByType:"Edited by",editors:[{id:"118814",title:"Dr.",name:"Herve",middleName:null,surname:"Seligmann",slug:"herve-seligmann",fullName:"Herve Seligmann"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"6060",title:"Mitochondrial Diseases",subtitle:null,isOpenForSubmission:!1,hash:"66c079bd70478fcc63072a8a42da4c33",slug:"mitochondrial-diseases",bookSignature:"Eylem Taskin, Celal Guven and Yusuf Sevgiler",coverURL:"https://cdn.intechopen.com/books/images_new/6060.jpg",editedByType:"Edited by",editors:[{id:"192567",title:"Prof.",name:"Eylem",middleName:null,surname:"Taskin",slug:"eylem-taskin",fullName:"Eylem Taskin"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"5232",title:"Restricted Growth",subtitle:"Clinical, Genetic and Molecular Aspects",isOpenForSubmission:!1,hash:"c604493aaeaf8258adc42b2d7dc9b22d",slug:"restricted-growth-clinical-genetic-and-molecular-aspects",bookSignature:"Maria del Carmen Cardenas- Aguayo",coverURL:"https://cdn.intechopen.com/books/images_new/5232.jpg",editedByType:"Edited by",editors:[{id:"169616",title:"Dr.",name:"Maria del Carmen",middleName:null,surname:"Cardenas-Aguayo",slug:"maria-del-carmen-cardenas-aguayo",fullName:"Maria del Carmen Cardenas-Aguayo"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}],booksByTopicTotal:4,mostCitedChapters:[{id:"63421",doi:"10.5772/intechopen.80871",title:"Directed Mutations Recode Mitochondrial Genes: From Regular to Stopless Genetic Codes",slug:"directed-mutations-recode-mitochondrial-genes-from-regular-to-stopless-genetic-codes",totalDownloads:441,totalCrossrefCites:6,totalDimensionsCites:9,book:{slug:"mitochondrial-dna-new-insights",title:"Mitochondrial DNA",fullTitle:"Mitochondrial DNA - New Insights"},signatures:"Hervé Seligmann",authors:[{id:"118814",title:"Dr.",name:"Herve",middleName:null,surname:"Seligmann",slug:"herve-seligmann",fullName:"Herve Seligmann"}]},{id:"60263",doi:"10.5772/intechopen.75555",title:"True Mitochondrial tRNA Punctuation and Initiation Using Overlapping Stop and Start Codons at Specific and Conserved Positions",slug:"true-mitochondrial-trna-punctuation-and-initiation-using-overlapping-stop-and-start-codons-at-specif",totalDownloads:622,totalCrossrefCites:7,totalDimensionsCites:8,book:{slug:"mitochondrial-dna-new-insights",title:"Mitochondrial DNA",fullTitle:"Mitochondrial DNA - New Insights"},signatures:"Eric Faure and Roxane Barthélémy",authors:[{id:"182675",title:"Prof.",name:"Eric",middleName:null,surname:"Faure",slug:"eric-faure",fullName:"Eric Faure"},{id:"233312",title:"Dr.",name:"Roxane-Marie",middleName:null,surname:"Barthélémy",slug:"roxane-marie-barthelemy",fullName:"Roxane-Marie Barthélémy"}]},{id:"62150",doi:"10.5772/intechopen.77366",title:"Renaissance of the Tautomeric Hypothesis of the Spontaneous Point Mutations in DNA: New Ideas and Computational Approaches",slug:"renaissance-of-the-tautomeric-hypothesis-of-the-spontaneous-point-mutations-in-dna-new-ideas-and-com",totalDownloads:453,totalCrossrefCites:7,totalDimensionsCites:8,book:{slug:"mitochondrial-dna-new-insights",title:"Mitochondrial DNA",fullTitle:"Mitochondrial DNA - New Insights"},signatures:"Ol’ha O. Brovarets’ and Dmytro M. Hovorun",authors:[{id:"212825",title:"Dr.",name:"Dmytro",middleName:null,surname:"Hovorun",slug:"dmytro-hovorun",fullName:"Dmytro Hovorun"},{id:"212839",title:"Dr.",name:"Ol\\'Ha",middleName:"Oleksandrivna",surname:"Brovarets\\'",slug:"ol'ha-brovarets'",fullName:"Ol\\'Ha Brovarets\\'"}]}],mostDownloadedChaptersLast30Days:[{id:"63034",title:"Mitochondrial Dysfunction Associated with Doxorubicin",slug:"mitochondrial-dysfunction-associated-with-doxorubicin",totalDownloads:870,totalCrossrefCites:1,totalDimensionsCites:4,book:{slug:"mitochondrial-diseases",title:"Mitochondrial Diseases",fullTitle:"Mitochondrial Diseases"},signatures:"Celal Guven, Yusuf Sevgiler and Eylem Taskin",authors:[{id:"192567",title:"Prof.",name:"Eylem",middleName:null,surname:"Taskin",slug:"eylem-taskin",fullName:"Eylem Taskin"},{id:"195229",title:"Dr.",name:"Celal",middleName:null,surname:"Guven",slug:"celal-guven",fullName:"Celal Guven"},{id:"206996",title:"Prof.",name:"Yusuf",middleName:null,surname:"Sevgiler",slug:"yusuf-sevgiler",fullName:"Yusuf Sevgiler"}]},{id:"68488",title:"Mitochondrial Dysfunction as a Key Event during Aging: From Synaptic Failure to Memory Loss",slug:"mitochondrial-dysfunction-as-a-key-event-during-aging-from-synaptic-failure-to-memory-loss",totalDownloads:538,totalCrossrefCites:1,totalDimensionsCites:3,book:{slug:"mitochondria-and-brain-disorders",title:"Mitochondria and Brain Disorders",fullTitle:"Mitochondria and Brain Disorders"},signatures:"Claudia Jara, Angie K. Torres, Margrethe A. Olesen and Cheril Tapia-Rojas",authors:[{id:"183873",title:"Dr.",name:"Claudia",middleName:null,surname:"Jara",slug:"claudia-jara",fullName:"Claudia Jara"},{id:"299224",title:"Dr.",name:"Cheril",middleName:null,surname:"Tapia-Rojas",slug:"cheril-tapia-rojas",fullName:"Cheril Tapia-Rojas"},{id:"299227",title:"Ms.",name:"Angie K.",middleName:null,surname:"Torres",slug:"angie-k.-torres",fullName:"Angie K. Torres"},{id:"299230",title:"Ms.",name:"Margrethe",middleName:null,surname:"A. Olesen",slug:"margrethe-a.-olesen",fullName:"Margrethe A. Olesen"}]},{id:"60594",title:"Mitochondrial Trafficking by Prohibitin-Kinesin-Myosin- Cadherin Complex in the Eye",slug:"mitochondrial-trafficking-by-prohibitin-kinesin-myosin-cadherin-complex-in-the-eye",totalDownloads:554,totalCrossrefCites:1,totalDimensionsCites:2,book:{slug:"mitochondrial-diseases",title:"Mitochondrial Diseases",fullTitle:"Mitochondrial Diseases"},signatures:"Srinivas R. Sripathi, Weilue He, Johnpaul Offor, Diana R. Gutsaeva\nand Wan Jin Jahng",authors:[{id:"205781",title:"Associate Prof.",name:"Wan Jin",middleName:null,surname:"Jahng",slug:"wan-jin-jahng",fullName:"Wan Jin Jahng"},{id:"244413",title:"Dr.",name:"Srinivasa R.",middleName:null,surname:"Sripathi",slug:"srinivasa-r.-sripathi",fullName:"Srinivasa R. Sripathi"},{id:"244414",title:"Dr.",name:"Weilue",middleName:null,surname:"He",slug:"weilue-he",fullName:"Weilue He"},{id:"244415",title:"Dr.",name:"Johnpaul",middleName:null,surname:"Offor",slug:"johnpaul-offor",fullName:"Johnpaul Offor"},{id:"244416",title:"Dr.",name:"Diana R.",middleName:null,surname:"Gutsaeva",slug:"diana-r.-gutsaeva",fullName:"Diana R. Gutsaeva"}]},{id:"58886",title:"Modulation of Mitochondria During Viral Infections",slug:"modulation-of-mitochondria-during-viral-infections",totalDownloads:999,totalCrossrefCites:1,totalDimensionsCites:2,book:{slug:"mitochondrial-diseases",title:"Mitochondrial Diseases",fullTitle:"Mitochondrial Diseases"},signatures:"Latif Reshi, Hao-Ven Wang and Jiann-Ruey Hong",authors:[{id:"66487",title:"Prof.",name:"Jiann",middleName:"Ruey",surname:"Hong",slug:"jiann-hong",fullName:"Jiann Hong"},{id:"206951",title:"Dr.",name:"Lateef",middleName:null,surname:"Reshi",slug:"lateef-reshi",fullName:"Lateef Reshi"},{id:"213164",title:"Dr.",name:"Hao -Ven",middleName:null,surname:"Wang",slug:"hao-ven-wang",fullName:"Hao -Ven Wang"}]},{id:"62948",title:"Pyrethroid Insecticides as the Mitochondrial Dysfunction Inducers",slug:"pyrethroid-insecticides-as-the-mitochondrial-dysfunction-inducers",totalDownloads:831,totalCrossrefCites:2,totalDimensionsCites:2,book:{slug:"mitochondrial-diseases",title:"Mitochondrial Diseases",fullTitle:"Mitochondrial Diseases"},signatures:"Celal Guven, Yusuf Sevgiler and Eylem Taskin",authors:[{id:"192567",title:"Prof.",name:"Eylem",middleName:null,surname:"Taskin",slug:"eylem-taskin",fullName:"Eylem Taskin"}]},{id:"61735",title:"Phylogenetic Evolution and Phylogeography of Tibetan Sheep Based on mtDNA D-Loop Sequences",slug:"phylogenetic-evolution-and-phylogeography-of-tibetan-sheep-based-on-mtdna-d-loop-sequences",totalDownloads:565,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"mitochondrial-dna-new-insights",title:"Mitochondrial DNA",fullTitle:"Mitochondrial DNA - New Insights"},signatures:"Jianbin Liu, Xuezhi Ding, Yufeng Zeng, Xian Guo, Xiaoping Sun and\nChao Yuan",authors:[{id:"236937",title:"Ph.D.",name:"Liu",middleName:null,surname:"Jianbin",slug:"liu-jianbin",fullName:"Liu Jianbin"}]},{id:"52131",title:"Genetic Determinants of Short Stature",slug:"genetic-determinants-of-short-stature",totalDownloads:1217,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"restricted-growth-clinical-genetic-and-molecular-aspects",title:"Restricted Growth",fullTitle:"Restricted Growth - Clinical, Genetic and Molecular Aspects"},signatures:"Diana Miclea",authors:[{id:"181083",title:"Ph.D.",name:"Diana",middleName:null,surname:"Miclea",slug:"diana-miclea",fullName:"Diana Miclea"}]},{id:"67194",title:"PET Imaging of Mitochondrial Function in the Living Brain",slug:"pet-imaging-of-mitochondrial-function-in-the-living-brain",totalDownloads:419,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"mitochondria-and-brain-disorders",title:"Mitochondria and Brain Disorders",fullTitle:"Mitochondria and Brain Disorders"},signatures:"Hideo Tsukada",authors:[{id:"179616",title:"Dr.",name:"Hideo",middleName:null,surname:"Tsukada",slug:"hideo-tsukada",fullName:"Hideo Tsukada"}]},{id:"58585",title:"Estrogen and Mitochondrial Function in Disease",slug:"estrogen-and-mitochondrial-function-in-disease",totalDownloads:657,totalCrossrefCites:0,totalDimensionsCites:1,book:{slug:"mitochondrial-diseases",title:"Mitochondrial Diseases",fullTitle:"Mitochondrial Diseases"},signatures:"Ved P. Mooga, C. Roger White and Samantha Giordano-Mooga",authors:[{id:"193624",title:"Prof.",name:"C. Roger",middleName:null,surname:"White",slug:"c.-roger-white",fullName:"C. Roger White"},{id:"213186",title:"Dr.",name:"Samantha",middleName:null,surname:"Giordano-Mooga",slug:"samantha-giordano-mooga",fullName:"Samantha Giordano-Mooga"},{id:"213187",title:"Dr.",name:"Ved",middleName:null,surname:"Mooga",slug:"ved-mooga",fullName:"Ved Mooga"}]},{id:"58888",title:"Mitochondria at the Base of Neuronal Innate Immunity in Alzheimer’s and Parkinson’s Diseases",slug:"mitochondria-at-the-base-of-neuronal-innate-immunity-in-alzheimer-s-and-parkinson-s-diseases",totalDownloads:544,totalCrossrefCites:1,totalDimensionsCites:1,book:{slug:"mitochondrial-diseases",title:"Mitochondrial Diseases",fullTitle:"Mitochondrial Diseases"},signatures:"A. Raquel Esteves, Diana F. Silva, Daniel Santos, Emanuel Candeias,\nFilipa Filipe and Sandra M. Cardoso",authors:[{id:"164998",title:"Ph.D.",name:"Ana",middleName:null,surname:"Esteves",slug:"ana-esteves",fullName:"Ana Esteves"},{id:"164999",title:"Prof.",name:"Sandra",middleName:null,surname:"Cardoso",slug:"sandra-cardoso",fullName:"Sandra Cardoso"},{id:"213149",title:"Dr.",name:"Diana F",middleName:null,surname:"Silva",slug:"diana-f-silva",fullName:"Diana F Silva"},{id:"213153",title:"Dr.",name:"Daniel",middleName:null,surname:"Santos",slug:"daniel-santos",fullName:"Daniel Santos"},{id:"213154",title:"Dr.",name:"Emanuel",middleName:null,surname:"Candeias",slug:"emanuel-candeias",fullName:"Emanuel Candeias"},{id:"213155",title:"Dr.",name:"Filipa",middleName:null,surname:"Filipe",slug:"filipa-filipe",fullName:"Filipa Filipe"}]}],onlineFirstChaptersFilter:{topicSlug:"mitochondrial-genetics",limit:3,offset:0},onlineFirstChaptersCollection:[],onlineFirstChaptersTotal:0},preDownload:{success:null,errors:{}},aboutIntechopen:{},privacyPolicy:{},peerReviewing:{},howOpenAccessPublishingWithIntechopenWorks:{},sponsorshipBooks:{sponsorshipBooks:[{type:"book",id:"10176",title:"Microgrids and Local Energy Systems",subtitle:null,isOpenForSubmission:!0,hash:"c32b4a5351a88f263074b0d0ca813a9c",slug:null,bookSignature:"Prof. Nick Jenkins",coverURL:"https://cdn.intechopen.com/books/images_new/10176.jpg",editedByType:null,editors:[{id:"55219",title:"Prof.",name:"Nick",middleName:null,surname:"Jenkins",slug:"nick-jenkins",fullName:"Nick Jenkins"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}}],offset:8,limit:8,total:1},route:{name:"profile.detail",path:"/profiles/145226/ehsan-sheybani",hash:"",query:{},params:{id:"145226",slug:"ehsan-sheybani"},fullPath:"/profiles/145226/ehsan-sheybani",meta:{},from:{name:null,path:"/",hash:"",query:{},params:{},fullPath:"/",meta:{}}}},function(){var e;(e=document.currentScript||document.scripts[document.scripts.length-1]).parentNode.removeChild(e)}()