Effect of exogenous factors on extracellular alkaline ribonuclease synthesis in Bacillus mesentericus

Bacillus mesentericus was found to assimilate nucleic acids as a source of nitrogen and phosphorus. Nucleic acids added to the medium as a source of nitrogen or phosphorus stimulated synthesis of ribonuclease. When washed bacterial cells were incubated for a short period of time in a fresh nutrient medium containing RNA, synthesis of RNAase was also induced. Synthesis of the enzyme was inhibited by high concentrations of chloramphenicol and actinomycin D, and stimulated by low concentrations of actinomycin D. Therefore, alkaline RNAase is an inducible enzyme which participates in the nutrition processes of bacteria.     

Regenerative growth of asvitic hepatoma 22A]

A study was made of the recurrent growth of ascite hepatoma 22A, occurring at transplantation of 11-12-day old tumours to new hosts. The mitotic activity of the hepatoma was found to increase by 3 to 4 times (12-15 hours after inoculation). This increased cell proliferation is due mainly to a sharp shortening of all the periods of mitotic cycle. During the recurrent growth, the resting R1 cells resume their mitotic cycle. No resumption of the mitotic cycle by the resting R2 cells was observed