Inducing effect of cortisone and insulin on the activity of beta-galactosidase in the E. coli strains K12.

Individual and combined effects of cortisone and insulin on the synthesis of beta-galactosidase in the strains E. coli K 12 200 PS/Flac and M-308 and the possiblity of cortisone uptake by the bacterial cell under different temperature conditions were investigated in their dynamics. When insulin and cortisone are applied simultaneously in doses showing individually the greatest stimulative effect on the synthesis of beat-galactosidase, no summation of the effect of the hormones occurs in the strain E. coli 200 PS/Flac in the presence of IPTG while in the strain E. coli ML-308 simultaneous application of insulin and cortisone induces a negligible increase in the activity of beta-galactosidase. Tests for the incorporation of [3H] cortisone into the strains E. coli 200 PS/Flac and ML-308 have shown that the hormone is taken up by the bacterial cell immediately after its addition to the incubation medium, reaching its maximum after 5 min of incubation and maintaining the same level in the subsequent 30 min. The incorporation of [3H] cortisone at a temperature of 37degrees C is markedly higher than at 4degrees C. Preliminary incubation of the cultures with unlabelled cortisone and insulin resulted in a decrease in the uptake of [3H] cortisone by the bacterial cell.