Study of Genotoxic Effects of Tonarol

Genotoxic effects of 2,6-di-tret-butyl-4-methylphenol (tonarol) were studied using four test systems: the Ames test, the SOS chromotest, the cytogenetic test with rootlets of onion (Allium cepa), and the in vivo micronucleus test. Tonarol did not affect gene mutation induction in Salmonella typhimurium tester strains, the SOS response in the Escherichia coli strain PQ37, chromosomal aberrations in cells of onion (Allium cepa) rootlets, and micronuclei in erythrocytes of peripheral blood of CBA x C5713 L/G mice. Tonarol induced cell division in A

Bacterial ribonuclease: Mutagenic effect in microbial test-systems

Pure enzyme samples of ribonuclease from Bacillus intermedius 7P (known commercially as 'binase') were investigated for genotoxicity in four microbial tests: the Ames plate incorporation method, Ara(R)-assay; the prophage induction test; and the DNA-repair test. The weak mutagenic effect of binase at high concentrations (0.1 mg/plate, 1 mg/plate) was established by induction of forward Ara(R)-mutations and histidine-reverse mutations (both frameshift mutations and base pair substitution). Metabolic activation with rat or chicken liver, human placenta or plant (from tulip bulbs) microsomal fractions in vitro was seen to abolish the binase mutagenicity. Bacillus intermedius 7P ribonuclease appears to possess DNA damaging activity in uvrA- and polA- mutants, but not in the recA-deficient Escherichia coil strain, and exhibits an induction of recA-dependent mutagenesis detected by the 8-fold increase of the prophage-induction level in lysogenic Bacillus subtilis culture and by the 5-fold increase of this level in the Streptomyces lavendulae 3 lysogenic strain. The importance of the roles of both of enzyme catalytic activity and native structure is emphasized. A proposed mechanism for exogenous ribonuclease action is discussed. Bacillus intermedius 7P ribonuclease probably does not act as a direct genotoxic agent interacting with DNA, but could provoke nucleotide imbalance through its catalytic action on membrane-associated RNAs, which results in alteration of DNA replication and, as a consequence, in recA-dependent mutagenesis

The effect of thermal treatment on the catalytic activity and biological properties of bacillus intermedius ribonuclease

Bacillus intermedius ribonuclease (binase), which is known to exert a growth-stimulating effect at low concentrations and a genotoxic effect at high concentrations, loses these abilities completely after exposure to 100°C for 10 min, but retains approximately 96% of its catalytic activity and structural integrity. Other types of modification, such as photoinactivation and site-specific mutagenesis, gave rise to enzyme forms with unaltered structure but reduced (sometimes to trace amounts) catalytic activity. Çrenotoxipity was always proportional to the catalytic activity of the native enzyme, while a notable growth-stimulating effect may be exerted by enzymes with low activity. The loss of biological activity of thermoinactivated binase was related to the increase in the number of negatively charged groups on the enzyme surface, which led to a substantial decline in the adhesive properties of the enzyme

The effect of thermal treatment on the catalytic activity and biological properties of Bacillus intermedius ribonuclease

Bacillus intermedius ribonuclease (binase), which is known to exert a growth-stimulating effect at low concentrations and a genotoxic effect at high concentrations, loses these abilities completely after exposure to 100°C for 10 min, but retains approximately 95% of its catalytic activity and structural integrity. Other types of modification, such as photoinactivation and site-specific mutagenesis, gave rise to enzyme forms with unaltered structure but reduced (sometimes to trace amounts) catalytic activity. Genotoxicity was always proportional to the catalytic activity of the native enzyme, while a notable growth-stimulating effect could be exerted by enzymes with low activity. The loss of biological activity of thermoinactivated binase was related to the increase in the number of negatively charged groups on the enzyme surface, which led to a substantial decline in the adhesive properties of the enzyme. © 2001 MAIK "Nauka/Interperiodica"

An investigation of antigenotoxic properties of plant extracts of Chelidonium majus L., Plantago major L. and Tussilago farfara L

The antigenotoxic properties of the sap from three medicinal plants, the greater celandine (Chelidonium majus L.), the greater plantain (Plantago major L.), and coltsfoot (Tussilago farfara L.), were studied using two bacterial test systems (SOS chromotest and Rec assay). It was determined using the combined effect of the plant sap and model genotoxicants on the cells of test strains that the plant sap of the greater celandine reveals a dismutagenic effect decreasing the genotoxic effect of nalidixic acid in the SOS chromotest and furacilin in the Rec assay. The plants sap of the greater celandine and coltsfoot (in 1: 10 and 1: 100 dilutions) demonstrated a bioantimutagenic effect in the SOS chromotest because pre-incubation of the E. coli PQ37 cells test strain with the sap of these plants resulted in a significant decrease of the genotoxic effect of nalidixic acid. The antigenotoxic effect of the greater plantain sap was not statistically significant in both test systems. Possible mechanisms of determining the antigenotoxic properties of the plant sap from greater celandine and coltsfoot are discussed. © 2011 Pleiades Publishing, Ltd

SOS-inducing ability of native and mutant microbial ribonucleases

The results of genotoxicity testing of microbial ribonucleases from Bacillus species with different catalytic activity obtained by site-directed mutagenesis in SOS chromotest are reported. At the concentrations 0.1-1 mg/ml, the induction factor for wild-type bacillar binase, barnase and mutant Arg58Lys binase with 100% activity was found to be significantly higher than 1.5 (1.8-2.8). Mutant RNases having decreased catalytic activity (binases with replacements Lys26Ala, Arg61Gln, His101Glu) or through natural inhibitor barstar inactivated wild-type RNase exhibited no SOS-inducing potency. The ability of native bacillar RNases and mutant enzymes possessing high catalytic activity comparable with the activity of wild-type RNase to cause the SOS response indicates that genotoxicity is mediated through the probable cleavage of cellular RNA. The possible mechanisms of mutagenesis induced by catalytically active RNases are discussed

Mutagenic potential as an integral index of soil pollution by oil components

A study was made on soil samples contaminated by oil and oil-polluted waste waters of Tatarstan oil fields. The mutagenic ability of the samples was evaluated by the plate modification of the Ames test (Salmonella/microsomes). Oil-polluted soils were shown to exhibit medium and weak mutagenic potential. The mutagenic effect was increased by metabolic activation by microsome fractions of rat liver and human placenta. The soil samples contaminated by waste waters of oil wells did not exhibit mutagenic effect. No reliable correlation was revealed between mutagenic effect and some chemical indices (heavy metal and 3,4-Benzpyrene content in the samples). Copyright © 1996 by MAHK Hayka/Interperiodica Publishing

Induction of the SOS-response in test bacteria by bacillus intermedius RNase

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 cplOS WT (a phenomenon related to the SOS-response). An enzyme with a His101Glu-substituted active center, exhibiting residual catalytic activity, failed to induce the SOS-response in an SOS-chromotest with E. coli PQ 37, indicating dependence of the SOSinducing effect of the enzyme on its catalytic activity. It is suggested that the effect of active ribonuclease on membrane-bound and cytoplasmic RNA causes a change in the nucleotide pool and, as a consequence, elicits the SOS-response of the cell

Antagonistic actinobacteria screening for biocontrol against phytopathogenic micromycetes of potato plant

The present study was focused on isolation and estimation of antagonistic properties of soil actinobacteria against phytopathogenic micromycetes causing diseases of potato plants. It was shown that one of 13 isolated actinobacteria significantly inhibited growth of phytopathogenic fungi of Fusarium genus. The results obtained allow us to consider the active actinobacterial isolate as a perspective agent for biological control of plant fungal diseases.Работа выполнена за счет средств субсидии, выделенной КФУ для выполнения государственного задания в сфере научной деятельности (проект 14–83)

Cytotoxic and genotoxic effects of β-(triphenylphosphonio)ethyl carboxylate and of N,N′-bis(dihexylphosphinoylmethyl)-1,4- diaminocyclohexane

Background: Several organophosphorous compounds (OPs) are now being tested therapeutically. Cholinesterase inhibition, which in large doses makes these agents effective pesticides, may also be useful in other doses for treating dementia. Metrifonate, for example, has been used to treat schistosomiasis and is undergoing trials for the treatment of primary degenerative dementia. Material/Methods: Here we report the characterization of newly synthesized OPs from the group of phosphobetaines [β-(triphenylphosphonio)ethyl carboxylate, PB] and of alpha-aminophosphoryl compounds [N,N′- bis(dihexylphosphinoylmethyl)-1,4-diaminocyclohexane, AP] according to their toxic and genotoxic properties determined in prokaryotic and eukaryotic test systems. Results: The absence of toxicity towards Gram-negative bacteria and of genotoxicity in Ames mutagenicity assay and in SOS-chromotest did not exclude the cytotoxic effect of PB towards NIH3T3 mouse fibroblasts, which supports the notion of an extremely diverse interspecies response to OPs. In contrast, AP demonstrated toxic properties detected by antibacterial effect as well as by the inhibition of the proliferation and respiration of fibroblasts. The enzymatic transformation of the compound is necessary to reveal the genotoxic properties of AP. The role of mammalian microsomal enzymes and of bacterial C-P lyase in the formation of AP genotoxic metabolites is under discussion. Conclusions: Neither toxicity nor genotoxicity of PB was found in bacterial tests. Cytotoxic and mutagenic effects of AP were detected. The data contribute to the investigation of the biological activity of novel organophosphates which could be useful for the future development of OP-based therapeutics