[DNA synthesis and degradation in the cells of Bacillus stearothermophilus]

ATP-dependent and ATP-independent synthesis of DNA was studied on nucleotide-permeable cells of Bacillus stearothermophilus. The effect of temperature, pH, ionic strength, and bivalent metal ions on both types of DNA synthesis was investigated as well as their susceptibility to an SH-blocking agent. The level of ATP-independent synthesis of DNA in the cells of Bac. stearothermophilus was found to be ten times higher than that in E. coli. In the semipermeable cells of Bac. stearothermophilus, 90% of DNA of the chromosome was accessible to their nucleases. The temperature optimum of the activity of DNA polymerases and nucleases in the cells treated with toluene coincided with the optimum of the bacterial growth.