Chemotaxis, Bacterial: A Model for Sensory Receptor Systems
Like eukaryotic cells that respond to hormones, growth factors, or neurotransmitters, motile bacteria detect spécifie chemical compounds and respond appropriately. The response is an altered swimming pattern resulting in net progress toward a more favorable chemical environment. This behavior, called chemotaxis, has been studied extensively in the closely related enteric bacteria, Escherichia coli and Salmonella typhimurium. Biochemical and genetic studies of those species have identified molecular components that mediate tactic behavior, including receptor proteins exposed on the cell surface, and delineated some of the mechanisms by which the components function. Studies of other bacterial species have revealed striking parallels with the tactic system of the enterics. It seems likely that Chemotaxis in all bacterial species is accomplished by analogous sensory response systems that link receptors to flagella. In fact, homology has been detected among analogous protein components of the sensory systems from widely different bacteria. The current understanding of the chemotactic system in E. coli is summarized in the following paragraphs.
KeywordsBacterial Chemotaxis Sensory Transduction Swimming Pattern Flagellar Motor Motile Bacterium
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