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The bacterial stress response enables bacteria to survive adverse and fluctuating conditions in their immediate surroundings. Various bacterial mechanisms recognize different environmental changes and mount an appropriate response. A bacterial cell can react simultaneously to a wide variety of stresses and the various stress response systems interact with each other by a complex of global regulatory networks. Bacteria can survive under diverse environmental conditions and in order to overcome these adverse and changing conditions, bacteria must sense the changes and mount appropriate responses in gene expression and protein activity. The stress response in bacteria involves a complex network of elements that acts against the external stimulus. Bacteria can react simultaneously to a variety of stresses and the various stress response systems interact (cross-talk) with each other. A complex network of global regulatory systems leads to a coordinated and effective response. These regulatory systems govern the expression of more effectors that maintain stability of the cellular equilibrium under the various conditions. Stress response systems can play an important role in the virulence of pathogenic organisms. In bacteria some of the most important stress response systems are: * Heat shock response, controlled by the sigma factor sigma 32 * Envelope stress response, controlled mainly by the sigma factor sigma E and the Cpx two-component system * Cold shock response, which governs expression of RNA chaperones and ribosomal factors * General stress response, which depends on the sigma factor sigma S * (p)ppGpp-dependent stringent response, which reduces the cellular protein synthesis capacity and controls further global responses upon nutritional downshift Further examples include the secretion of protein domain, TauD, to break down taurine into sulphur in times of need and YodA in toxic metal response. ==See also== * Environmental microbiology * Fight-or-flight response * Heat shock protein * Microbiology * Molecular microbiology 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「bacterial stress response」の詳細全文を読む スポンサード リンク
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