Stress proteins and cross-protection by heat shock and salt stress in Bacillus subtilis. |
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Authors: | U V?lker H Mach R Schmid M Hecker |
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Institution: | Institute of Microbiology, Ernst-Moritz-Arndt-University, Greifswald, Germany. |
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Abstract: | Bacillus subtilis induced a set of general stress proteins in response to a salt or heat stress. Cells subjected to a mild heat stress showed a protective response which enabled them to survive otherwise lethal temperatures (e.g. 52 degrees C). In a similar way bacteria were enabled to survive toxic concentrations of NaCl by pretreatment with lower salt concentrations. A mild heat shock induced a cross-protection against lethal salt stress. The pretreatment of cells with low salt, however, was less effective in the induction of thermotolerance than a preceding mild heat stress. Three stress proteins were identified on the basis of their N-terminal amino acid sequences as homologues of GroEL, DnaK and ClpP of Escherichia coli. The role of general and specific stress proteins in the induction of thermotolerance/salt tolerance and cross-protection is discussed. |
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