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Etude des hémoprotéines senseurs à oxygène bactériens FixL et Dos.

Abstract : Adaptation to the environment is essential for the survival of any organism, bacteria to humans. To adapt quickly to extremely diverse environments and environmental fluctuations, the prokaryotic systems have been developed, capable of detect and respond to vital molecules or toxic to their development. In addition to factors stress such as temperature, pH, the cell must adapt to changes in concentration nutrients and diatomic gases. Indeed, the modification of one or more environmental parameters triggers altered expression of genes, allowing changes in the protein composition and thus an adaptation of metabolism to new conditions. A parameter particularly important is the environmental oxygen levels. The transition to life limited oxygen, or vice versa, has been particularly studied in bacteria. These have several chains of electron carriers and use at any one time which is the favorably on the energy plan. In the presence of oxygen as electron acceptor favorable, the bacteria use the breathing oxygenation, which is characterized by the synthesis enzymes of cytochrome oxidase, whereas in the absence of oxygen or condition low pressure oxygen (or hypoxia), they set up the nitrate respiration, characterized by the synthesis of respiratory quinone intermediates (Pelmont J., 1993). The carrier's final track "nitrate is nitrate reductase, a key enzyme inhibited by oxygen. The presence of diatomic oxygen therefore requires bacteria deep changes in metabolism, either because they have to readjust their system energy production, either because they are struggling against the toxicity of oxygen for that they have an arsenal enzyme. Knowledge processes Biochemical through which adaptation is essential to understanding of cell function.
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Submitted on : Wednesday, July 28, 2010 - 3:58:20 PM
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  • HAL Id : pastel-00002324, version 1



Latifa Bouzhir. Etude des hémoprotéines senseurs à oxygène bactériens FixL et Dos.. Sciences du Vivant [q-bio]. Ecole Polytechnique X, 2006. Français. ⟨pastel-00002324⟩



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