[Selection of Escherichia coli and Pseudomonas putida cultures with an enhanced resistance to immobilization on polyacrylamide gel].

Clones of Escherichia coli (A4, A70, G60) and Pseudomonas putida (A70, G30) with an elevated resistance to the process of immobilization in polyacrylamide gel and to the action of monomeric acrylamide were selected from the parent E. coli IBPM B115 and P. putida. The isolated cultures remained resistant to the above actions for a long time. The frequency at which cells with the elevated resistance appeared was comparable with the frequency of bacterial mutations. The plasmid analysis did not reveal the presence of plasmid DNA in the cells of the isolated cultures. The decrease in the viability index of bacterial populations caused by their immobilization in polyacrylamide gel and by the action of monomeric acrylamide did depend on the growth phase. The cells were more resistant to these actions in the stationary phase. The isolated cultures were more resistant as compared to the parent cultures irrespective of the growth phase.