Eric Hallerman

By Simonel Sandu, Brian Brazil and Eric Hallerman

Part of the book: Aquaculture and the Environment

By S. Sandu and E. Hallerman

Part of the book: Biodegradation

By Pawel Michalak, Lin Kang, Serena Ciparis, William Henley, Jess Jones, Andrew Phipps and Eric Hallerman

Freshwater mussels of the Clinch and Powell rivers of Virginia in the southeastern United States have been heavily impacted by runoff, leachates, or spills of materials related to coal extraction, processing, and use. Assays quantifying sublethal impacts of such wastes are needed. We assessed gene transcriptional markers in a laboratory study under controlled conditions, focusing upon arsenic (arsenate, As(V)) and sulphate, contaminants related to coal mining and processing. Pheasantshells Actinonaias pectorosa collected from the Clinch River were subjected to a 28-day chronic exposure to control or environmentally relevant concentrations of each compound. We compared gene expression in digestive gland among parasite-free, female pheasantshells among control and contaminant-exposed individuals using the Illumina HiSeq platform. Statistically significant differential expression of particular genes was observed among control mussels and those exposed to either arsenate or sulfate. Chemical stress was as likely to cause under-expression as it was to cause over-expression of particular genes. Arsenate and sulfate induced up- or down-expression of different suites of 50-100 genes. Our results provide proof-of-principle for using RNAseq technology to approach issues of toxicogenomics in freshwater mussels. The candidate markers could be validated for quantitative PCR assays for rapidly assessing single-gene responses to exposure to toxic compounds.

Part of the book: Organismal and Molecular Malacology

By Joanne E. Printz, Joseph Williams and Eric M. Hallerman

Population genetic evidence suggests differentiation among evolutionarily significant units of southern and northern Appalachian brook trout, with the zone of contact in southwestern Virginia. Before this differentiation was recognized, brook trout of northern origin were stocked throughout the southeastern United States. In order to determine this differentiation, established allozyme markers were used to classify 56 southwest Virginia populations as southern, northern, or introgressed. Variation at 4 polymorphic loci, including the diagnostic creatine kinase (CK-A2*) locus, indicated that 19 populations were of southern origin, 5 of northern origin, and 32 of mixed genetic origin. Data compiled among genetic studies of brook trout in the southern Appalachians showed that the southern/northern break is sharp, occurring at the New/Roanoke-James watershed divide. New River drainage populations exhibited the southern allele at high frequency, suggesting their historic native character as southern, with presence of northern alleles due to stocking or stream capture events. In conclusion, the present study suggests that management of southern Appalachian brook trout should include: (1) genetically cognizant planning of stocking events, (2) management of populations on a stream-by-stream basis, (3) prioritized conservation of pure southern brook trout populations, and (4) use of southern Appalachian hatchery stocks in restoration efforts.

Part of the book: Biological Resources of Water