Interrogating novel biosynthetic sources for the production of polybrominated diphenyl ethers

项目摘要/摘要 海洋中多溴二苯醚(PBDEs)的存在已经对人类健康造成了危害 自20世纪70年代作为阻燃剂使用以来，导致了包括甲状腺在内的无数有毒影响 荷尔蒙失衡、神经毒性和发育障碍。自2004年以来，人造卫星的进入 由于政府对其生产的限制，进入环境中的多溴二苯醚一直受到限制。不过，这个 随着全球各地继续检测到多溴二苯醚，环境健康危机依然存在，普遍影响 食用海鲜、海洋哺乳动物和人类。2005年，人们发现并不是所有的多溴二苯醚都是 人为来源；通常检测到羟化和甲氧基化的多溴二苯醚(OH-BDEs和MeO-BDEs， 分别)均为天然产物。此外，对羟基BDEs和MeO-BDEs的毒性进行了比较。 被发现超过了人为的多溴二苯醚。研究表明，多溴二苯醚及其化合物的持久性 环境中的羟化和甲氧基化的同系物及其通过食物的能力 然而，少数已知的OH/MeO-BDE细菌和藻类生产者并不占全球 代表海洋中的分子。在这里，我提议探索新的OH/MeO-BDE的可能性 生产者通过在海水、海洋沉积物中寻找线索来检查可能的常见饮食来源， 和海洋动物相关的微生物区系。 该建议旨在从环境样本中挖掘元基因组和元翻译数据，以 评估OH/MeO-BDE生产者在环境中的分布和使用的化学物质 生物合成机械。海洋细菌中已知的OH/MeO-BDE生物合成酶的序列将 最初用作探针，然后使用生物合成逻辑来识别感兴趣的新酶。在AIM 1，我将使用这种方法来处理产生OH/MeO-BDE的红藻，首次建立分子 真核系统中多溴二苯醚生物合成的基础。低值与高值条件下的差异表达分析 生产条件将被用来促进对假定的生物合成基因的鉴定。在目标2中， 已知的细菌基因和新发现的真核基因将被用作探针来评估元基因组学。 海水、沉积物和海洋动物相关微生物存在多溴二苯醚生物合成的数据 基因。最后，将在目标3中探索多溴联苯醚生物合成酶的酶学，以提供详细的 了解多溴二苯醚生物合成的潜在机制，特别是在独特的黄素依赖 负责芳香族脱羧基溴化反应的卤代酶。我预计这项研究将提供一种 对多溴二苯醚的生物合成及其全球分布的宝贵了解。此外，这项研究很可能 促进研究以管理环境中的多溴二苯醚生产，并对未被研究的问题提供新的见解 酶的种类。

Project Summary/Abstract The presence of polybrominated diphenyl ethers (PBDEs) in the ocean has been a human health hazard since their implementation as flame retardants in the 1970s, causing a myriad of toxic effects including thyroid hormone imbalances, neurotoxicity, and developmental disorders. Since 2004, the entrance of anthropogenic PBDEs into the environment has been limited by government restrictions on their production. However, this environmental health crisis remains as PBDEs continue to be detected around the globe, impacting commonly consumed seafood, marine mammals, and humans. In 2005, it was discovered that not all PBDEs are of anthropogenic origin; commonly detected hydroxylated and methoxylated PBDEs (OH-BDEs and MeO-BDEs, respectively) were found to be natural products. Furthermore, the toxicity of OH-BDEs and MeO-BDEs were found to surpass that of anthropogenic PBDEs. Studies have demonstrated the persistence of PBDEs and their hydroxylated and methoxylated congeners in the environment and their ability to be passed through the food web; however, the handful of known OH/MeO-BDE bacterial and algal producers do not account for the global representation of the molecules in the oceans. Here, I propose to explore the possibility of novel OH/MeO-BDE producers by examining probable common dietary sources by searching for clues in sea water, ocean sediments, and marine animal-associated microbiota. This proposal aims to mine metagenomic and metatranscriptomic data from environmental samples to assess the distribution of OH/MeO-BDE producers in the environment and the chemistry employed in the biosynthetic machinery. The sequences of known OH/MeO-BDE biosynthesis enzymes from marine bacteria will be used initially as probes, followed by the use of biosynthetic logic to identify new enzymes of interest. In Aim 1, I will use this approach toward OH/MeO-BDE-producing red algae to establish, for the first time, the molecular basis for PBDE biosynthesis in an eukaryotic system. Differential expression analysis under low and high producing conditions will be employed to facilitate the identification of putative biosynthetic genes. In Aim 2, known bacterial genes and newly identified eukaryotic genes will be used as probes to assess metagenomic data from sea water, sediment, and marine animal associated microbes for the presence of PBDE biosynthesis genes. Finally, the enzymology of PBDE biosynthetic enzymes will be explored in Aim 3 to provide a detailed understanding of the underlying mechanisms of PBDE biosynthesis, specifically in the unique flavin dependent halogenases responsible for aromatic decarboxylative bromination. I anticipate that this research will provide an invaluable understanding of PBDE biosynthesis and its global distribution. Furthermore, this research will likely facilitate studies to manage PBDE production in the environment and provide new insights into understudied classes of enzymes.