Research Interest:
Effect of natural and anthropogenic stressors on marine invertebrate immune function. As human populations increase in coastal areas, the contact of humans with coastal waters and the organisms that live in those waters also increases. Natural stressors, (low pH, low dissolved oxygen, high temperature) and stressors that result from human impacts on the coastal (heavy metals, organics, pesticides) can impact normal functions of the immune system in vertebrates (fish) and invertebrates (shrimp and oysters), thereby increasing their susceptibility to infectious disease. These organisms can, in turn, act as vectors for human disease. In collaboration with Dr. Lou Burnett, members of our laboratory have developed challenge models of infectious disease in fish, shrimp and oysters and are using these models to determine how stressors interfere with normal mechanisms of pathogen clearance and killing. We have hypothesized that many stressors modulate the process of signal transduction in cells of the immune system. Therefore, we are studying the receptors normally used for pathogen recognition and the molecular pathways that trigger the cellular immune response. For example, recent studies have shown that sublethal levels of hypoxia increase the susceptibility of the shrimp, Litopenaeus vannamei, to infection by the environmental pathogen, Vibrio parahaemolyticus. On-going investigations by graduate student researchers in our laboratory focus on those pathways involved in bacterial recognition and killing by hemocytes that may be most sensitive to oxygen pressures. Additional projects are examining the role of the crustacean gill as an organ of immune function and the development of multi-antibiotic resistance in bacterial flora associated with shrimp and oysters.