Research progress on mechanism of surface sensing in Escherichia coli
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 agricultura...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Zhejiang University Press
2017-11-01
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| Series: | 浙江大学学报. 农业与生命科学版 |
| Subjects: | |
| Online Access: | https://www.academax.com/doi/10.3785/j.issn.1008-9209.2017.07.261 |
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| Summary: | 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 attach 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. |
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| ISSN: | 1008-9209 2097-5155 |