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大肠杆菌表面感应机制研究进展

花匠小妙招
2024-12-18 01:19

大肠杆菌表面感应机制研究进展华中农业大学资源与环境学院，农业微生物学国家重点实验室，武汉 430070Research progress on mechanism of surface sensing in Escherichia coliWANG Liliang, GAO Chunhui, WU Yichao, HUANG Qiaoyun, CAI Peng*(State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China) 摘要相关文章 Metrics摘要：

大肠杆菌是人和动物胃肠道的主要兼性厌氧菌群，既能在宿主体内生存，也能吸附在环境中的固体介质表面形成生物膜而得以存活和传播。吸附是生物膜形成的关键，它能改变细胞运动性和代谢等相关基因的表达，进而影响细胞的性质和行为。细菌对表面的“感知”以及初始吸附后细胞的“响应”过程统称为“表面感应”。对细菌表面感应机制的研究有助于我们加深对微生物尤其是病原菌在土壤环境中的存活和迁移，以及土壤生物膜形成过程的理解。本文结合多种微生物表面感应的研究进展，阐述了表面感应的概念，重点关注了近期有关大肠杆菌表面感应的研究，并对未来工作进行了展望。

关键词：表面感应; 吸附; 大肠杆菌; 生物膜 Abstract:

Escherichia coli is a kind of facultative anaerobic bacteria which is commonly found in the host gastrointestinal tract and natural environments. The presence of pathogenic E. coli in manure and sewage is a serious threat to the health of humans and animals, which can spread to consuming agricultural products and enter the food industry chain. In the above processes, these pathogens can survive and spread in the form of surface-associated biofilm. Initial attachment is the first step of the biofilm development. When cells attached on the surface, physiological properties of bacteria are altered. It can reshape cell morphology and behavior by changing the expressions of different genes, such as, those related to cell motility and metabolism. Therefore, the attachment on various biotic (plant roots or leaves) and abiotic (soil particles) surfaces is the key step for bacterial survival in different environments. The way that cells sense a surface and respond upon surface attachment is referred as“surface sensing”, which consists of a great many behaviors, including the workings of the apparatus that allows perception of proximal surfaces, the apparatus that allows selection of different surfaces for attachment, and the biochemical cascade and physical consequences that follow the recognition of surfaces. E. coli is a one of the most studied microorganisms in surface sensing. The bacteria can sense the solid surface by the cell surface structure and regulate attachment by controlling cell motility and surface properties through the intracellular signaling system. E. coli can sense solid surfaces through flagella, type I fimbriae, membrane proteins (such as OmpX and NlpE), lipopolysaccharide (LPS) and exopolymeric substances (EPS). In addition, cell density can also affect cell attachment. The buoyant density of bacteria is usually 1.06-1.13 g/mL, which leads to the slow deposition of cells onto surfaces from suspension in bulk liquid. The buoyant density of E. coli increases as they enter stationary phase, which facilitates their rapid deposition on surfaces. Two-component system is the main intracellular signaling system induced by attachment. Specifically, the regulation of pili by two-component system is an important way to control surface sensing. As far as we know, the CpxAR, RcsAB and EnvZ-OmpR pathways can respond to surface signals and regulate pili expression in attachment. Nonetheless, bacterial surface sensing is a phenomenon that is still not well understood at the level of physical chemistry, biochemistry, genetics, and cell biology. The surface sensing of E. coli is a complex, multi- step and coordinated process which may be regulated and/or affected by many factors, particularly in complicated soil systems. A further understanding of the mechanisms of surface sensing will improve our knowledge on not only how microbes, especially pathogens, survive and transmit in soils, but also how soil biofilm is formed.

Key words:surface sensing attachment Escherichia coli biofilm收稿日期: 2017-07-26出版日期: 2017-11-01基金资助: 国家重点研发计划重点专项（2016YFD0800206）；国家自然科学基金优秀青年基金（41522106）通讯作者:蔡鹏（http://orcid.org/0000-0002-3103-1542） E-mail: cp@mail.hzau.edu.cnViewedFull text

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