| dbo:abstract
|
- 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 counteracts 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. These systems can include immediate responses such as chaperones, as well as slower responses like transcriptional regulation to control protein production, latency, and others. Stress response systems can play an important role in the virulence of pathogenic organisms. Their stress response systems, such as entering into a latent state, can allow them to survive the stressful conditions inside of the host or other surroundings. There are regulatory systems that respond to changes in temperature, pH, nutrients, salts, and oxidation. The response level is based on the amount of change that occurs in the environment. The response is highest when changes occur under stress conditions, in this case the control networks are called stress response systems. These systems are very similar within prokaryotes and some of the systems, specifically the heat shock response, are conserved in eukaryotes and archaea. While the systems are extremely similar, the conditions under which they are activated differ greatly from organism to organism. The systems that activate the response to environmental change have many control elements. These control elements can be specific to one gene or they can control a large group of genes. When control elements control a large group of genes it is called a regulon. A regulon is a group of genes that are all regulated by the same control pattern. A stimulon is all the genes who express responses to the same condition. The control elements also regulate the expression of genes during various environmental conditions including starvation, sporulation and others. (en)
|
