海洋细菌对烃类物质的细胞感应、跨膜转运与代谢调控机制研究

Hydrocarbons and corresponding microbial degraders are widespread in global oceans, everywhere in coastal, pelagic, polar areas, and from the surface to deep. Marine hydrocarbons can be originated from natural processes at both sea bottom and upper layers, and maritime accidents with substantial oil spills. Hydrocarbons can be served as carbon and energy sources for a variety of microorganisms along the Earth historic time and all over the world. Microbes play a key role in removing the oil pollutants in the sea to restore the habitats of marine lives. However, we are still not sure how the bacteria response to the appearance and disappearance of these organics, especially at molecular levels like hydrocarbon sensing, uptake, and metabolic pathway regulation, which certainly discount our efforts in recognizing the microbes’ role in environments and to evaluate the fate of oil pollutants in environments. Here, based on the previous achievements, we tend to go further to dissect the processes at molecular level, from cellular sensing to intracellular metabolism of both aliphatic and aromatic hydrocarbons with Alcanivorax and Cycloclasticus as the representatives of two kinds of hydrocarbon degraders, aiming to find new mechanisms, and to construct the comprehensive metabolic pathways, to gain insights into the molecular mechanisms of cell sensing, signal relaying, cross membrane transport, precise regulation of different hydrocarbon pathways. Advances after these efforts will do helps to evaluate the contributions of such microbes in the biogeochemistry cycling of marine environments, in past and presently.

烃类广泛分布于近海、深海、极地、大洋各种海洋环境。烃类为众多海洋微生物提供了碳源和能源。海洋烃类物质既有上层和海底的自然过程来源，也有人类活动引起的大量石油泄漏。广泛分布的烃类降解菌在烃类矿化过程中，特别是在大量溢油后的环境修复过程中，起着关键作用。然而，细菌的烃类代谢机制，特别是烃类感应、信号传导、跨膜转运、代谢途径调控等机制还缺乏认识。相关认识不到位阻碍我们对细菌响应烃类过程以及烃类环境归宿的评估。本研究拟以海洋中最具代表性的烷烃与多环芳烃降解菌（食烷菌和解环菌）为对象，研究烃感应蛋白、跨膜转运蛋白、sRNA调控作用、烃趋化及信号传导途径等，目标是发现新机制、构建全局代谢网络，深刻理解海洋细菌对烃类物质感应、胞内转运过程，以及对不同烃类代谢途径的调控机制，研究结果将为评估烃类降解菌所参与的海洋生物地球化学过程与环境贡献提供参考。

烃类广泛分布于各种海洋环境，种类与来源多样。既有来源藻类生物合成的烷烃，也有海底活动产生各种烃类物质；此外，海上石油开采、海上石油运输等人类活动引起的大量石油泄漏，对海洋生态系统构成威胁。在石油污染环境的修复过程中，烃类降解菌起着关键作用。自然界中有很多海洋微生物可以利用烷烃与芳烃作为碳源和能源生长，然而细菌对烃类的细胞感应、信号传导、跨膜转运、代谢途径调控等机制还缺乏认识，这影响了我们对细菌在烃突然出现时的响应过程以及烃类物质在环境中归宿的评估。本研究以海洋代表性烷烃与多环芳烃降解菌为对象，研究烃感应蛋白、跨膜转运蛋白、sRNA调控作用、烃趋化及信号传导途径等，目标是发现新机制、构建代谢网络，深刻理解微生物与烃类物质互作的分子机制，为评估烃类代谢微生物在过去、现在海洋环境中的环境作用与生态贡献提供参考。.主要科学发现与意义：1.烃类物质跨膜转运机制研究获得新认识：以食烷菌为研究对象，鉴定了与烷烃跨内膜运输的相关蛋白；以Cycloclasticus sp. P1为例，发现了细菌对PAHs的跨膜运输机制。2.在烃的细胞表面感应与信号转导方面，发现了细菌胞外PAHs的感应与信号转导途径；发现了细菌胞内对PAH感应、信号转导与代谢调控机制。3.鉴定了参与细菌烷烃代谢调控的重要sRNA及其调控机制；4.在海洋烃降解菌新类群、新功能及其环境分布特征等方面获得新进展；5.海洋烃代谢细菌环境适应性及其生态贡献获得重要进展。项目已发表SCI论文15篇，授权发明专利4项。总之，通过该项目实施，在海洋细菌烷烃与多环芳烃的细胞感应、跨膜转运、代谢调控、系统演化与环境作用等多个层面获得重要进展，为认识烃类有机物与海洋细菌互作过程及其对海洋碳循影响及环境贡献提供了重要理论基础。此外，该研究为烃类生物传感器研制与石油污染微生物修复剂开发提供了新的功能基因与降解菌。