Signaling during swarmer cell differentiation

群体细胞分化过程中的信号传导

• 批准号: 6861818
• 负责人: Rasika M Harshey
• 金额: $ 26.25万
• 依托单位: UNIVERSITY OF TEXAS AT AUSTIN
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-30 至 2007-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6861818
• 关键词: Escherichia coli; Salmonella typhimurium; bacterial genetics; bacterial polysaccharides; bacterial proteins; bacterial somatic antigen; biofilm; biological signal transduction; cell differentiation; cell motility; chemotaxis; cilium /flagellum motility; gene expression; gene mutation; life cycle; microorganism culture; microorganism growth; microorganism population study; virulence

DESCRIPTION: (provided by the applicant) The focus of our research is to study signaling mechanisms that lead to differentiation of S.typhimurium into hyperfiagellated swarmer cells when propagated on a solid growth surface. Knowledge gained from these studies will be extended to the area of bioflims and virulence. A swarmer colony secretes 'slime' which is mainly composed of polysaccharides; biofilms are bacterial colonies within 'slime layers', which play an important role in the persistence of infections. Our current hypothesis is that slime is essential for swarming in at least two ways: provides the milieu for swarming motility, and constitutes the signal for swarmer cell differentiation. Preliminary results have ruled out signals such as specific amino acids, pH changes, oxygen, iron starvation, increased viscosity, flagellar rotation or known autoinducer systems. Extensive transposon mutagenesis has led to the isolation of swarming mutants, a majority of which were defective in lipopolysaccharide (LPS) synthesis, a large number defective in the chemotaxis signaling pathway, and some defective in putative two-component signaling components. A mutation in waaG (LPS core modification): secreted copious amounts of slime and showed a precocious swarming phenotype. We have suggested that the 0-antigen improves surface 'wettability' required for swarm colony expansion, that the LPS core could play a: role in slime generation, and that multiple two-component systems cooperate to promote swarmer cell differentiation. We propose to 1. Investigate the role of the well-understood chemotaxis signaling system in swarmer cell differentiation, 2. Investigate roles of two of the newly implicated two-component signaling systems in swarming and in virulence, and 3. Test polysaccharides as potential swarming signals, and understand the relationship between slime elaborated by moving swarmer cells and that secreted by adherent bacteria in bioflims.

描述：（由申请人提供）我们研究的重点是研究 信号传导机制导致链球菌分化为 当在固体生长表面繁殖时，超毛细胞的蜂群细胞。 这些研究从这些研究中获得的知识将扩展到生物叶夫妇的领域 和毒力。一个主要由 多糖；生物膜是“粘液层”中的细菌菌落， 在感染的持久性中起着重要的作用。我们目前的假设 粘液至少以两种方式蜂拥而至：提供 环境群的运动，并构成了蜂群的信号 分化。初步结果排除了特定的信号 氨基酸，pH变化，氧气，铁饥饿，粘度增加， 鞭毛旋转或已知的自动引诱系统。广泛的转座子 诱变导致了蜂群突变体的隔离，其中大多数 在脂多糖（LPS）合成中有缺陷，大量有缺陷 在趋化信号通路中，有些在推定中有缺陷 两个组件信号传导组件。 WAAG中的突变（LPS核心修饰）： 分泌大量的粘液，表现出早熟的蜂群表型。 我们建议0-抗原可改善所需的表面“润湿性” 对于群体的扩张，有限元核心可以发挥：在史莱姆中的角色 产生，以及多个两个组件系统合作以促进 堆积细胞分化。我们提议1。调查 蜂群分化中的趋化趋化信号传导系统，2。 研究两个新暗示的两个组件信号的作用 蜂群和毒力中的系统，以及3。测试多糖作为潜力 蜂拥而至的信号，并了解史莱姆阐述的关系 移动蜂群细胞，并由生物flim中的粘附细菌分泌。