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Molecular Biology

Researchers

Sonya Dyhrman, Rebecca Gast, John Stegeman, Mark Hahn, Carl Wirsen, Stefan Sievert, Lauren Mullineaux, Ann Tarrant, John Waterbury, Peter Tyack, Don Anderson, Rob Olson, Judy Mcdowell,
Matt Johnson

Molecular biology is an integrated and growing component of the research programs in the Biology Department at the Woods Hole Oceanographic Institution. Its powerful concepts and tools hold great promise for rapidly increasing knowledge of the phylogeny, biodiversity, ecology and population biology of marine organisms, their symbiotic interactions, and their biochemical, genetic and physiological adaptations to the ocean environment. WHOI biologists and affiliated scientists are using molecular approaches in coastal, open-ocean, deep-sea, and laboratory-based studies to explore a diverse array of biological oceanographic questions, ranging from the activities of individual organisms to the complex relationships of populations, communities and ecosystems.

Some of the areas where molecular approaches are being used by Biology Department staff include:

Microbial Ecology

Research in the laboratory of Rebecca Gast focuses on molecular phylogeny using srRNA gene sequences and the development of oligonucleotide probes for detection and identification of protists. These techniques are currently being developed and applied to Acanthamoeba and symbiotic algae in planktonic protists. Future research interests include the continued application of molecular biological techniques for the study of protist biodiversity and the identification of genes involved in the maintenance of symbiotic relationships between algae and planktonic marine invertebrates.

Chemical-Biological Interactions

The molecular mechanisms by which natural and man-made chemicals interact with vertebrate and invertebrate marine animals are being studied with biochemical, molecular and phylogenetic approaches. Work in the laboratory of John Stegeman focuses on the structure, function and regulation of cytochrome P450 enzymes and their role in cellular responses to chemical exposure. Research in Mark Hahn's laboratory is examining the comparative biochemistry and molecular biology of the aromatic hydrocarbon receptor, which mediates the biological activity of chlorinated hydrocarbon pollutants.

Deep-sea and Hydrothermal Vent Bacteria

Carl Wirsen and Stefan Sievert's group is using a combination of physiological and molecular approaches to study barophilic and psychrophilic deep-sea bacteria and to examine the diversity of microorganisms discovered at hydrothermal vents.

Larval Ecology and Dispersal

Research in Lauren Mullineaux's laboratory on organisms living in the patchy and ephemeral environments of seamounts and hydrothermal vents uses probes based on mitochondrial RNA sequences to identify larvae and gain population-level information about gene flow and geographic isolation.

Ecology of Marine Cyanobacteria and their Viruses

In the laboratory of John Waterbury, 23S rRNA sequence analysis and probes are being used to examine speciation and population ecology of cyanobacteria in the genus Synechococcus. The role of viruses in controlling Synechococcus populations is being examined with virus-specific antibodies.

Population Biology of Marine Mammals

Peter Tyack's group is using mitochondrial DNA sequences to elucidate the stock structure of pilot whales, with future studies planned for other species of toothed whales, including some that may be threatened by fishing activities.

Shellfish Diseases

The laboratory of Judy McDowell studies a leukemia-like neoplastic disease in soft-shell clams. Monoclonal antibodies specific to a cell-surface protein on neoplastic hemocytes allow early diagnosis of the disease, and a reverse transcriptase assay is being developed to evaluate viral replication as a causative factor.

Physiological Ecology of Phytoplankton

In the laboratory of Don Anderson, the dinoflagellates responsible for the harmful algal blooms known as "red tides" are being studied with immunological and nucleic acid-based molecular probes to detect the organisms and indicate their physiological status. Rob Olson's group is using flow cytometry and function- specific DNA -based probes to study the distribution and seasonal population cycling of marine prochlorophyte picoplankton and ultra-phytoplankton. In a collaborative effort between the labs of John Waterbury and Eric Webb, specific molecular markers defining iron and phosphorus limitation of the marine cyanobacterium Trichodesmium are being developed.