There is overwhelming evidence that polybrominated diphenyl-ethers (PBDEs) and polybrominate pyrroles (PBPs) are bioaccumulating in the marine food chain and that these compounds are of biological origin. While the harmful effects of halogenated organic compounds (HOCs) on humans and the environment are only beginning to be understood, their structural similarities to anthropogenic pollutants suggest they represent an emerging and poorly characterized group of marine toxins. The overall goal of Project 1 is to identify the biological sources of PBDEs and PBPs in the Southern California Bight. This goal will be accomplished through a comprehensive sampling paradigm targeting bulk and size-fractionated plankton, sediments, benthic algae, and filter feeding invertebrates. Sampling efforts will capitalize on small boat and shipboard resources available through SIO and expertise provided by plankton expert Melissa Carter (SIO) and collaborators at the J. Craig Venter Institute (see letter of support from L. Zeigler). Project 1 activities will be tightly integrated with Project 3 and the Analytical Core, which will identify and quantify PBDEs and PBPs in the samples collected. This information will be used to link specific compounds with sample types and to guide subsequent microbial cultivation efforts and cultivation-independent diversity studies. Metagenomic data generated from Project 2 will, provide a complimentary analysis of microbial community composition and insight into the biosynthetic genes associated with HOC production. This information will be used in quantitative PCR and CARD-FISH studies designed to assess the numbers and location of HOC-producing bacteria and relevant biosynthetic genes in different sample types. HOCs that cannot be identified by Project 3 based on comparisons with reference data will be isolated, structurally characterized, and provided to Project 3 for toxicological evaluation and as GC-MS standards. Select PBPs previously identified from environmental samples will be synthesized to provide baseline toxicological data and GC-MS standards. A major effort will be placed on the cultivation of HOC-producing bacteria, as there is considerable preliminary evidence that they represent an important biological source of these compounds. This research represents the first major effort to identify the biological sources and sinks of an increasingly important group of marine pollutants in a major US coastal environment.

National Institute of Health (NIH)
National Institute of Environmental Health Sciences (NIEHS)
Research Program Projects (P01)
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Special Emphasis Panel (ZES1-LKB-J (P1))
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University of California San Diego
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Agarwal, Vinayak; Miles, Zachary D; Winter, Jaclyn M et al. (2017) Enzymatic Halogenation and Dehalogenation Reactions: Pervasive and Mechanistically Diverse. Chem Rev 117:5619-5674
Arakawa, Neal; Aluwihare, Lihini I; Simpson, Andre J et al. (2017) Carotenoids are the likely precursor of a significant fraction of marine dissolved organic matter. Sci Adv 3:e1602976
Agarwal, Vinayak; Blanton, Jessica M; Podell, Sheila et al. (2017) Metagenomic discovery of polybrominated diphenyl ether biosynthesis by marine sponges. Nat Chem Biol 13:537-543
Hong, Mee Young; Hoh, Eunha; Kang, Brian et al. (2017) Fish Oil Contaminated with Persistent Organic Pollutants Induces Colonic Aberrant Crypt Foci Formation and Reduces Antioxidant Enzyme Gene Expression in Rats. J Nutr 147:1524-1530
El Gamal, Abrahim; Agarwal, Vinayak; Diethelm, Stefan et al. (2016) Biosynthesis of coral settlement cue tetrabromopyrrole in marine bacteria by a uniquely adapted brominase-thioesterase enzyme pair. Proc Natl Acad Sci U S A 113:3797-802
Teufel, Robin; Agarwal, Vinayak; Moore, Bradley S (2016) Unusual flavoenzyme catalysis in marine bacteria. Curr Opin Chem Biol 31:31-9
Harvey, Elizabeth L; Deering, Robert W; Rowley, David C et al. (2016) A Bacterial Quorum-Sensing Precursor Induces Mortality in the Marine Coccolithophore, Emiliania huxleyi. Front Microbiol 7:59
El Gamal, Abrahim; Agarwal, Vinayak; Rahman, Imran et al. (2016) Enzymatic Reductive Dehalogenation Controls the Biosynthesis of Marine Bacterial Pyrroles. J Am Chem Soc 138:13167-13170
Hong, Mee Young; Lumibao, Jan; Mistry, Prashila et al. (2015) Fish Oil Contaminated with Persistent Organic Pollutants Reduces Antioxidant Capacity and Induces Oxidative Stress without Affecting Its Capacity to Lower Lipid Concentrations and Systemic Inflammation in Rats. J Nutr 145:939-44
Agarwal, Vinayak; Li, Jie; Rahman, Imran et al. (2015) Complexity of naturally produced polybrominated diphenyl ethers revealed via mass spectrometry. Environ Sci Technol 49:1339-46

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