2-DIMENSIONAL GEL-ELECTROPHORESIS ANALYSIS OF THE RESPONSE OF PSEUDOMONAS-PUTIDA KT2442 TO 2-CHLOROPHENOL

The effects of exposure of Pseudomonas putida KT2442 to 2-chlorophenol as a model for the chemical stress response were examined by two-dime nsional polyacrylamide gel electrophoresis, Individual protein concent rations were determined at 45, 65, and 95 min following the addition o f 2-chlorophenol at a concentration of 1.63 mM to exponentially growin g cultures of P. putida KT2442 by silver staining the separated protei ns, The changes in the protein concentrations could be classified into four categories, namely those which increased continuously during exp osure, those which decreased in concentration, those which showed a co ncentration peak at some point following exposure, and those which wer e essentially unaffected. Thirty proteins with isoelectric points betw een pH 4 and 6 increased in concentration, 27 decreased, and 90 had a concentration maximum or minimum between 45 and 95 min, Of those prote ins with isoelectric points between 5.5 and 10, 68 increased in concen tration, 39 decreased in concentration, and 47 showed a concentration peak in the middle of the sampling period, Thus, in the evaluation of the stress response, a functional description requires an understandin g both of proteins which are required at higher concentrations and of those whose presence appears to be no longer essential.