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V A Sibirnyĭ

Publications and source records attributed to V A Sibirnyĭ.

9 recordsLinked to original sources

[Enterobacterial sensitivity to colicins in the presence of enterochelin].

The correlation between the colicine resistance of the reference and isolated strains of enterobacteria and their capacity for the biosynthesis of enterocheline, as well as the influence of exogenous enterocheline on the colicine sensitivity of enterobacteria were studied. In the wild strains of enterobacteria sensitivity to colicines was shown to have no correlation with capacity for the accumulation of catechol-type sideriphores. In some cases exogenous enterocheline prevents the lethal effect of colicines on the cultures of microorganisms capable of the biosynthesis of enterocheline.

Catechols↗

[Formation of iron-binding metabolites by bacteria of the Enterobacteriaceae family].

The capacity of Enterobacteriaceae strains cultivated in a synthetic medium for the biosynthesis of catechols and hydroxamates has been studied. Among the strains under study all strains of the genera Salmonella (8 strains), Escherichia (102 strains), Citrobacter (5 strains), Enterobacter (2 strains), Serratia (1 strain) synthesize catechols. In the genus Shigella (128 strains) all Sh. flexneri serovars (79 strains) do not synthesize catechols, other representatives of this genus synthesize iron-fixing metabolites The synthesis of catecholsin the pathogenic Escherichia serovars is 1.5-2 times lower than in the non-pathogenic and opportunistic enterobacterial strains. Among the representatives of the genus Klebsiella (82 strains) catechols are synthesized by Kl. pneumoniae (68 strains) and not synthesized by kl. rhinoscleromatis (5 strains) and Kl. ozaenae (9 strains). Catechols are not synthesized also by all Proteus organisms under study (12 strains). All the enterobacteria under study show no capacity for the accumulation of hydroxamates under the conditions of catechol synthesis. The intensity of the synthesis of catechols depends on the composition of the medium and the conditions of cultivation.

Catechols↗

[Modern methods for formaldehyde, methanol and ethanol analysis].

It is necessary to create very specific and sensitive methods for assaying formaldehyde and methanol which are produced on the large scale and are very toxic and have mutagenic and carcinogenic action on living organisms. The methods for determination of formaldehyde, methanol and ethanol in the environment and fermentation products published and developed by the authors are reviewed in this paper. Most of the known methods are not sufficiently selective and sensitive and some of them are very expensive. Classical chemical, enzymatic, chemosensor and biosensor approaches used for methanol and formaldehyde assay are described. Enzymatic methods exploiting alcohol oxidase isolated from the mutant over-producing strain of methylotrophic yeast Hansenula polymorpha permit efficient determination of formaldehyde in industrial wastewaters. Enzymatic-chemical method based on the use of alcohol oxidase and 4-amino-5-hydrazine-3-mercapto-1,2,4-triazole (AHMT) allows simultaneous determination of methanol and formaldehyde. The technology of biosensor construction and their bioanalytical characteristics are described. Experimental data concerning amperometric and potentiometric biosensors based on the use of genetically modified cells of methylotrophic yeast Hansenula polymorpha are reviewed. The possibility to use alcohol oxidase-based biosensor for the assay of methanol in wastewater is demonstrated.

Biosensing Techniques↗