Collaborative Research: Pacific Research Center for Marine Biomedicine

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This accomplishment-based renewal of the Pacific Research Center for Marine Biomedicine (PRCMB) will be a collaboration between the University of Hawaii, Stanford, and Jackson State University. Research activities will be focused on two areas: (1) pathogens in tropical marine waters and (2) marine toxins and pharmaceutical lead discovery. This new research follows logically from accomplishments and discoveries made during the first phase of PRCMB funding. The pathogen and pathogen indicator work will focus on two streams that discharge to the ocean, one tropical (Kaelepulu on the island of Oahu) and the other temperate (San Pedro Creek in California). Monthly sampling at the two streams will be used to characterize seasonal variability in pathogen indicators and pathogen (bacterial and viral) concentrations using both culture-dependent and culture-independent (PCR-based) methods. These studies will be complemented by high-frequency sampling (ten-minute and hourly) during storm and dry-weather conditions to provide insights concerning spatial and temporal variability. Health-risk models (Quantitative Microbial Risk Assessment) will be developed using pathogen and pathogen indicator concentrations as input. The marine toxin work will concern ciguatoxin and beta?{methylamino-L-alanine (BMAA), both of which were the focus of recent PRCMB studies. Taking advantage of (1) the refinement of an assay (n2a) that is now capable of detecting ciguatoxin in fish tissue at concentrations ten times below the threshold associated with ciguatera symptomology and (2) a collaboration with Hawaiian recreational fishermen, PRCMB scientists will extract and concentrate sufficient ciguatoxin from fish tissue to obtain a molecular structure and will then, in collaboration with scientists at the University of Washington, work toward the development of an antibody-based assay for ciguatoxin. Ciguatoxin research will also involve (1) exploratory refinement of the n2a assay based on generation of nitric oxide by the n2a cell line and (2) an investigation of environmental conditions that trigger ciguatoxin production by taxonomically defined strains of the dinoflagellate Gambierdiscus. The BMAA work will build on initial studies to determine the prevalence of BMAA in marine cyanobacteria and the transfer of this toxin to higher trophic levels. The pharmaceutical studies will take advantage of the more than 2,500 microbial isolates in the PRCMB culture collection that have not yet been screened for bioactivity. Extracts of these cultures will be used in cell-based and molecular assays to determine if they affect the growth of microbial pathogens (Candida albicans, Escherichia coli, Staphlyococcus aureus, multi-drug resistant S. aureus, and vancomycin resistant Enterococcus faecium) or if they exert effects on human adenocarcinma cells, on protein kinase C, or on mitogen-activated protein kinase. Identification of the compounds responsible for reproducible bioactivity in these extracts will be accomplished through bioassay-guided fractionation and spectroscopic analysis (e.g., mass spectrometry, high-field nuclear magnetic resonance spectrometry) The broader impacts of the proposed work fall into several categories. One is certainly the public health endpoints: (i) credible methods that can be used to determine whether coastal waters are safe for recreational use, (ii) a simple, inexpensive assay for ciguatoxin in fish, (iii) a better appreciation of the threat to human health associated with the movement of BMAA through marine food chains, and (iv) the discovery of novel compounds with application to the treatment of human health problems. Second, this is a collaborative proposal with an historically black university (Jackson State University) and a female principal investigator from Stanford. Finally, the PRCMB will continue to train students and to collaborate with other institutions and Ocean and Human Health centers.