Physiology & Biogeochemistry



Mark Hahn, Judy McDowell, John StegemanStefan Sievert
Ann TarrantMatt JohnsonT. Aran Mooney

Shallow water benthic ecology

WHOI biologists are using a combination of traditional and modern approaches to investigate the comparative biochemistry and physiology of marine animals. Topics range from lipid metabolism and reproductive physiology to the regulation of gene expression and enzyme function. Studies involve a variety of taxonomic groups, including bivalve molluscs, crustaceans, teleost fish, elasmobranch fish, jawless fish, aquatic birds, and marine mammals.

Research in Mark Hahn's laboratory is aimed at understanding the function of biochemical pathways involved in chemical-biological interactions, especially ligand-receptor interactions, and the responses elicited by exposure to environmental contaminants and marine natural products. Research in John Stegeman's laboratory is focused broadly on the molecular basis underlying chemical-biological interactions and the effects of foreign chemicals on biota. This concerns effects in aquatic and terrestrial species, including humans. The work continues to center on the biochemistry and molecular biology of the cytochrome P450 enzymes, which are critical in chemical-biological interactions. The structure, function, regulation and evolution of these enzymes continue to be studied.

Overall objectives include:

1. Achieving a phylogenetic and mechanistic basis for predicting and evaluating chemical effects in many species.

2. Assessing the evolution of the P450 enzymes and their regulatory systems.

3. Establishing how ecological or environmental factors contribute to P450 gene diversity, by examining model systems from extreme environments.

4. Applying information and probes for P450 systems in assessing environmental exposure and effects in vertebrate animals.

Stegeman's laboratory is also investigating how chemicals affect cell proliferation, growth and differentiation, and the role of this process in chemically-induced diseases of marine species. Knowledge of the biochemistry of P450 enzymes, and the patterns of cell proliferation in growth and development, are being used to develop molecular markers of growth in vertebrates and invertebrates.