OCCURRENCE AND EXPRESSION OF CSPA, A COLD SHOCK GENE, IN ANTARCTIC PSYCHROTROPHIC BACTERIA

The homologue of cold shock gene cspA of Escherichia coli was detected in various isolates of Antarctic psychrotrophs representing both Gram -positive and Gram-negative bacteria. The Northern hybridization study indicated that the transcript size of cspA in the psychrotrophic Gram -positive bacterium Arthrobacter protophormiae and Gram-negative Pseud omonas fluorescens was similar to that of E. coli and that the cspA ho mologues in these two psychrotrophs were expressed constitutively at a law level both at 4 degrees C and 22 degrees C. In P.fluorescens, the expression of cspA mRNA was inducible after shift of temperature from 22 to 4 degrees C and the maximum level of induction occurred after 1 h which correlated with the time-lag required for growth of the cultu re after temperature shift.