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The experimental study identified the antiviral activity of Bacillus pumilus RNase (binase) against the reovirus of serotype 1/strain Lang. For the first time, it has been found that 50 μg/mL of binase effectively reduced the hemagglutinin and cytocidal activity of reovirus in Vero cell line. The preincubation of the enzyme with reovirus before infection of the cells inhibited the viral replication. To determine the stagedependent effect of reovirus reproduction upon binase inhibition, the infected cells were treated with binase or RNase A at different phases of the infectious cycle. The treatment of virus-infected cells has revealed that both enzymes have a maximal antiviral effect on the reovirus propagation during early phases of the reovirus reproduction cycle, with binase being more effective than RNase A. It has been hypothesized that the combined action of the oncolytic reovirus and binase is promising for the elimination of tumor cells carrying mutated RAS gene.

Microbial ribonucleases possess a broad spectra of biological activities, demonstrating stimulating properties at low concentrations and cytotoxicity and genotoxicity at high concentrations. The mechanisms of their penetration into the cells are not clear so far. This research is aimed to the study of Bacillus intermedius RNase (binase) penetration in alveolar lung epithelial cells - pneumocytes of type II. Using immunofluorescence we have shown for the first time have internalization of binase by primary non-differentiated pneumocytes АТII. The enzyme did not penetrate in pneumocytes MLE-12, which also derived from type II cells. However, binase was cytotoxic towards tumor MLE-12 cells, but not АТII cells. The obtained results testified the higher sensitivity of tumor cells towards binase compared with normal cells, and also showed that penetration of the enzyme into alveolar cells did not directly correlated with the cell death.

Hexylresorcinol has been demonstrated to induce chromosome aberrations in eukaryotic cells at doses of 0.5, 0.05, and 0.005 mg/g body weight. The metabolic transformation of hexylresorcinol in mice decreases its genotoxic effect. The mutagenic effect is retained for three days only after the administration of the highest dose of hexylresorcinol (0.5 mg/g); during the first two days, lower doses are also genotoxic. Therefore, hexylresorcinol doses lower than 0.5 mg/g body weight are metabolized within two days to the extent precluding the expression of the cytotoxic effect. After a single administration to mice, exogenous hexylresorcinol is transformed at a rate of 0.0025-0.025 mg/day.

Differential effects on proliferation of individual vs. combined administration of high- and low-molecular-weight microbial autoregulators (extracellular RNase from Bacillus subtilis and anabiosis-inducing factor d1) are reported for the first time for cultured cells of higher eukaryotes. Proliferation of ras-transformed mouse fibroblasts was affected by both autoregulators dose-dependently. The cytotoxic activity of individual regulators was directly related to their concentration. Unlike RNase, factor d1 (which functions as a chemical chaperone) exerted reversible effects. Studies of the effects of combined administration of the autoregulators demonstrated that pretreatment of the cells with low-dose d1 decreased the toxicity of RNase. Higher doses of d1 were required to attenuate the effects of toxic agents with more pronounced membrane tropism. The results obtained suggest that a universal system regulating the physiological activity of cells is operative in taxonomically remote organisms. The operation of the system is based on sequential changes in the structural organization and function of subcellular structures, induced by low- and high-molecular-weight autoregulators.

Microdoses of a preparation of pancreatic RNase were shown to stimulate the growth of Saccharomyces cerevisiae yeast. The effect was only retained at a certain inoculum/enzyme preparation ratio. Industrial tests of the preparation showed that the addition of RNase to the first reservoirs for culture accumulation (an inoculator and a seeding device) increased the yield of bakers' yeast and improved their quality.