Natural sources and microbial transformation of marine halogenated pollutants

天然多溴有机化合物，如羟基化多溴联苯醚（OH-BDEs）和多溴化吡咯（PBPs），最近出现的人类健康问题的化学品。这些人造卤化持久性有机污染物的天然产物亲属广泛分布在整个海洋食物网中，并在人类食用的海产食品中积累。研究人员已经证明，6-OH-BDE-47（甲状腺激素受体）等羟基溴化二苯醚和四溴吡咯（兰尼定受体）等多溴联苯是强效毒素，因此对人类构成潜在风险。然而，关于这些天然有机溴分子的来源范围、这些化学品如何进入海洋食物网并在其中移动、气候变化是否会影响其生产和积累以及人类是否受到天然卤代持久性有机污染物与人造持久性有机污染物的影响等问题仍然存在许多根本性问题。该项目旨在促进新出现的令人关切的海洋污染物的生物学和化学研究。更好地了解这些化合物的源和汇，将提高公众对海洋与人类健康之间联系的认识，并有助于改进有关鱼类消费和健康的准则和循证政策。该项目将资助一名研究生和一名博士后研究员。该项目由国家科学基金会和国家环境健康科学研究所共同资助，这些研究人员最近的发现为各种海洋细菌中微生物合成天然羟基溴二苯醚分子奠定了遗传和生物化学基础。然而，这些多溴持久性有机污染物在海洋生物区系中的全球分布和普遍存在并不能完全由迄今发现的来源来解释，这表明存在着其他生物来源，并且正在积极促进海洋食物网中的羟基溴二苯醚和甲氧基溴二苯醚积累。这一信息对于更准确地确定导致多溴二苯醚在海洋鱼类中自然积累并最终导致人类饮食接触风险的营养联系和相互转化至关重要。在该项目中，将利用转录组分析和生化酶表征，为海洋大型藻类（海洋栖息地中多溴联苯醚分子的一个明显但未表征的来源）建立多溴联苯醚分子生物合成和生物转化的新遗传和生化证据。将通过对鱼类和海洋生物进行全面分析，确定多溴二苯醚合成/转化的其他微生物来源，该奖项反映了NSF的法定使命，并通过利用基金会的智力价值和更广泛的影响进行评估，被认为值得支持审查标准。

Natural polybrominated organic compounds such as hydroxylated polybrominated diphenyl ethers (OH-BDEs) and polybrominated pyrroles (PBPs) have recently emerged as chemicals of human health concern. These natural product relatives of man-made halogenated persistent organic pollutants (POPs) are widely distributed throughout the marine food web and accumulate in seafood sources consumed by humans. Researchers have demonstrated that OH-BDEs such as 6-OH-BDE-47 (thyroid hormone receptor) and PBPs such as tetrabromopyrrole (ryanodine receptor) are potent toxins and thus pose a potential risk to humans. Many fundamental questions however remain about the extent of sources for these natural organobromine molecules, how these chemicals enter and move through the marine food web, whether changes in the climate will impact their production and accumulation, and whether humans are more or less impacted by natural halogenated POPs versus their man-made counterparts. This project seeks to advance the biology and chemistry of marine contaminants of emerging concern. A better understanding of the sources and sinks of these compounds will improve public understanding about links between oceans and human health and help improve guidelines and evidence-based policies regarding fish consumption and health. The project will support a graduate student and a postdoctoral researcher. The project is jointly supported by NSF and by the National Institute for Environmental Health Sciences (NIEHS).Recent discoveries by these investigators have rigorously established the genetic and biochemical basis for the microbial synthesis of natural OH-BDE molecules in diverse lineages of marine bacteria. However, the global distribution and ubiquity of these polybrominated POPs in marine biota cannot be fully explained by the sources discovered thus far, suggesting additional biogenic sources exist and are actively contributing to OH-BDE and MeO-BDE accumulation in the marine food web. This information is critical to more accurately identify trophic connections and interconversions that lead to natural PBDE accumulation in marine fish and ultimately, human dietary exposure risks. In this project, new genetic and biochemical evidence for the biosynthesis and biotransformation of PBDE molecules will be established for marine macroalgae, a conspicuous but uncharacterized source of PBDE molecules in marine habitats, using transcriptome analysis coupled with biochemical enzyme characterization. Additional microbial sources for PBDE synthesis/transformation will be characterized by the comprehensive analysis of fish and marine-mammal associated microbiomes using integrated genomic and metabolomic approaches combined with experimental microbiome enrichment reactors amended with PBDE molecules or biosynthetic substrates.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.