Hepatic Responses of Juvenile Fundulus heteroclitus from Pollution-adapted and Nonadapted Populations Exposed to Elizabeth River Sediment Extract.

The Hinton laboratory focuses on mechanistic toxicity in all life stages of small, aquarium model fish and in selected species with particular environmental relevance (freshwater and marine). With the latter, investigations focus on stressor responses and include follow up studies after oil spills. Studies with the laboratory model fish take advantage of the compressed life cycle to improve understanding of organellar, cellular and tissues responses that arise after exposure and follow either a temporal and/or a concentration gradient. At the end of these serial examinations, we have pioneered the use of high resolution light and fluorescent microscopy and electron microscopy in these small fish species to better understand resultant phenotypes and to correlate structural alteration with molecular biological studies. In this way we are anchoring phenotypes with gene expression. In individual fish where specific genes have been mutated (Collaboration with Dr. Keith Cheng, Hershey Medical Center, Hershey, PA) or in individuals exposed to organic substances of known or expected toxicity, structural analysis at various levels of biological organization enables integration across all levels of biological organization enabling whole body phenomics. Special projects include The Duke Superfund Research Center, 2P42-ESO10356-10A2, supported by NIH/NIEHS. Studies investigate responses of fish to polycyclic aromatic hydrocarbons and include early life stages and multigenerational effects. Contaminated and reference sites are included in these investigations of feral fish. Also, we receive funding as part of theme 2 of the Center for Environmental Implications of Nano Technology (CEINT). Our studies seek to determine whether there are specific toxic consequences upon exposure to nano silver (Ag NPs) versus exposure to conventional silver. We hosted Na Zheng (Angie), Visiting Investigator, Associate Professor, Northeast Institute of Geography and Agricultural Ecology, Chinese Academy of Sciences. She was the recipient of a K.C. Wong award supporting her role as visiting investigator. Together, we investigated metals mixtures and embryo toxicity. We collaborate with Stella Marinakos, Pratt School and CEINT on the synthesis and refinement of nanoselenium. This complements work done over the past year with seleno-methionine and sodium selenite in parental and embryo exposures. We continue to investigate ways to assess whole body responses of aquarium model fish and to link phenotype to genotype. Collaboration with the Stapleton laboratory has investigated alterations in embryo and larval zebrafish exposed to flame retardant compounds and selected metabolites. Here our morphologic investigations have helped to differentiate between delayed development and toxicity in the developing eye.

Dr. Di Giulio serves as Director of Duke University's Integrated Toxicology Program and the Superfund Basic Research Center.

Dr. Di Giulio's research is concerned with basic studies of mechanisms of contaminant metabolism, adaptation and toxicity, and with the development of mechanistically-based indices of exposure and toxicity that can be employed in biomonitoring. The long term goals of this research are to bridge the gap between mechanistic toxicological research and the development of useful tools for environmental assessment, and to elucidate linkages between human and ecosystem health. The bulk of Dr. Di Giulio's work employs a comparative approach with aquatic animals, particularly fishes, as models. Of particular concern are mechanisms of oxidative metabolism of aromatic hydrocarbons, mechanisms of free radical production and antioxidant defense, and mechanisms of chemical carcinogenesis, developmental perturbations and adaptations to contaminated environments by fishes.