[Effect of Bacillus intermedius RNAases with various catalytic activity on multiplication of Escherichia coli and Bacillus subtilis].

The effect of the Bacillus intermedius ribonuclease and its mutant forms derived by site-specific mutagenesis on the growth of gram-positive and gram-negative bacteria was studied. Both catalytically active and catalytically inactive (mutant) ribonucleases stimulated bacterial growth, the extent of stimulation correlating with the catalytic activity of the enzymes. It was suggested that the biological activity of exogenous ribonucleases is mainly due to their catalytic activity.

[Induction of the SOS-response with Bacillus intermedius RNAase].

This paper deals with the induction of the SOS-functions of a bacterial cell by the exogenous ribonuclease of Bacillus intermedius. Two test systems were employed, which made it possible to quantitatively estimate SOS-response induction activity in gram-positive and gram-negative bacteria. It was established that the catalytically active enzyme elicits the SOS-response in the cells of Escherichia coli PQ 37 and causes prophage induction in the lysogenic strain Bacillus subtilis 168 phi 105 WT (a phenomenon related to the SOS-response).