In order to control microbial resistance against commonly used antibiotics, it is indispensable to develop novel and efficient antimicrobial agents. For this purpose, metallic nanoparticles (mainly inorganic) with their antimicrobial activites represent an effective solution for this global problem. However, synthesis of nanoparticles involves the use of expensive, poisonous and dangerous chemicals responsible for different biological and environmental hazards. This fact increases the necessity of developing environment-friendly procedure by means of green synthesis (using plants) and extra-biological methods (using microbes such as bacteria and fungi). More recently, metallic nanoparticles, derived from fungal sources, have demonstrated their potential not only as a new-generation antimicrobial agents but also as anticancer agents. Therefore, this chapter is aimed to explore the various nanoparticles producing fungi with ultimate objective of elucidating the possible (i) mechanism of biosynthesis of metallic NPs by various fungi and (ii) mode of action of these mycosynthesized NPs on bacterial cell. This chapter would certainly increase our knowledge about interaction of nanoparticles with bacterial cell for their use in health biotechnology.
Part of the book: Functionalized Nanomaterials
Polyphenols have credentials to tackle the oxidative stress. Oxidative stress is the imbalance between free radicals production and antioxidant enzymes ability to tackle these radicals resulting the onset various metabolic related disorders. Polyphenols based foods have credential as a shield against these glitches mainly owing to their antioxidant potential. In this context, tea polyphenols have gained paramount attention of scientific community as therapeutic agents for the prevention and treatment of various oxidative stress induce maladies owing to their structural diversity, strong antioxidant ability and capacity to modulate various expression involved in the pathogenesis of these maladies. The notable polyphenols are catechins which are mainly present in green tea and further subdivided into various compounds like ECG, EGC, EGCG which has their unique therapeutic potential. The catechins undergo various structural changes and transformed into theaflavins and thearubigins in the process of black tea formation. These are high molecular weight polyphenols and promising candidates in obesity, diabetes and cancer treatment. Mechanistically, these polyphenols ameliorate oxidative stress by trapping the noxious radicals like superoxide and peroxyl, promote the activity of glutathione, suppressing the malondialdehyde (MDA) activity. The current chapter is an attempt to highlight the therapeutic potential of tea polyphenols.
Part of the book: Polyphenols
The emergence of carbapenem-resistant bacterial pathogens is a significant and mounting health concern across the globe. At present, carbapenem resistance (CR) is considered as one of the most concerning resistance mechanisms and mainly found in gram-negative bacteria of the Enterobacteriaceae family. Although carbapenem resistance has been recognized in Enterobacteriaceae from last 20 years or so, recently it emerged as a global health issue as CR clonal dissemination of various Enterobacteriaceae members especially E. coli, and Klebsiella pneumoniae are reported from across the globe at an alarming rate. Phenotypically, carbapenems resistance is in due to the two key mechanisms, like structural mutation coupled with β-lactamase production and the ability of the pathogen to produce carbapenemases which ultimately hydrolyze the carbapenem. Additionally, penicillin-binding protein modification and efflux pumps are also responsible for the development of carbapenem resistance. Carbapenemases are classified into different classes which include Ambler classes A, B, and D. Several mobile genetic elements (MGEs) have their potential role in carbapenem resistance like Tn4401, Class I integrons, IncFIIK2, IncF1A, and IncI2. Taking together, resistance against carbapenems is continuously evolving and posing a significant health threat to the community. Variable mechanisms that are associated with carbapenem resistance, different MGEs, and supplementary mechanisms of antibiotic resistance in association with virulence factors are expanding day by day. Timely demonstration of this global health concern by using molecular tools, epidemiological investigations, and screening may permit the suitable measures to control this public health menace.
Part of the book: Pathogenic Bacteria
Plant growth enhancement using plant beneficial bacteria has been viewed in the sustainable agriculture as an alternative to chemical fertilizers. Actinobacteria, among the group of important plant-associated bacteria, have been widely studied for its plant growth promotion activities. Actinobacteria are considered as a limelight among agriculturists for their beneficial aspects toward plants. They are naturally occurring spore-forming bacteria inhabiting the soil and known for their plant growth-promoting and biocontrol properties. The mechanisms behind these activities include nitrogen fixation, phosphate solubilization, siderophore production, and other attributes such as antifungal production of metabolites, phytohormones, and volatile organic compound. All these activities not only enhance the plant growth but also provide resistance in plants to withstand unfavorable conditions of the environment. Hence, this chapter emphasizes on the plant growth traits of actinobacteria and how far it was studied for enhanced growth and bio-fortification.
Part of the book: Plant Stress Physiology
Cutaneous candidiasis is a multipicture infection of the skin, generally caused by yeast like fungus c.albicans or other species of genus candida such as candida parapsilosis, candida tropicalis, candida glabrata but these species are unusual, secondary to skin diseases. Candida is flora of gut microbiota, rather than skin, although it is present on skin at some instances. Certain factor of candida species such as ability to evade host defense by biofilm formation, filamentous form and presence of tissue damaging enzyme phospholipase are attributed to pathogenicity. Cutaneous candida infection may occur in patient HIV/AIDS, cancer receiving chemotherapy, antibiotics, steroids therapy and in organ transplantation. Vesicles, pustules, maceration and fissuring are common symptoms on perineum, axilla and interriginous areas. Systemic and topical therapies are common treatment with different drugs. Single drug therapy as combination of anti-fungal, antibacterial and topical corticosteroid has marvelous results. Nystatin, Clotrimaziole and miconazole are efficiently reviewed topical drugs with 73–100% cure.
Part of the book: Candida and Candidiasis