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Iu R Malashenko

Publications and source records attributed to Iu R Malashenko.

63 records · Page 4Linked to original sources
PubMedDate not supplied

[Electron transport chain in a thermophilic methane-oxidizing culture of Methylococcus thermophilus].

The electron transport chain was studied in the obligate methane oxidizing culture of Methylococcus thermophilus during the oxidation of methanol (the source of carbon) which is an oxidized derivative of methane as well as during the oxidation of hydroxylamine which is an intermediate in the oxidation of ammonium (the source of nitrogen) by Mc. thermophilus cells. Cytochromes a, b and c are involved in electron transport. Cytochrome cco and cytochrome c554 have been isolated from the cell-free extract of Mc. thermophilus and purified. A scheme for electron transport operating in the oxidation of methanol and hydroxylamine is suggested on the basis of studying the characteristics of these cytochromes. Cytochrome a was shown to be a component of terminal oxidase. Cytochromes b are connected with membranes and also found in the composition of hydroxylamine oxidase. Cytochrome cco and, possibly, terminal oxidase (cytochromes a) are involved, in the oxidation of CH3OH by methanol dehydrogenase, in electron transport; cytochrome c554 as well as cytochrome b and c in the composition of hydroxylamine oxidase participate in electron transport in the oxidation of NH2OH by hydroxylamine oxidase. The characteristics of the electron transport system in Mc. thermophilus are discussed.

Alcohol Oxidoreductases↗
PubMedDate not supplied

[Effect of carbon dioxide on the methylotrophic metabolism of Candida boidinii].

The activity of enzymes involved in carbon metabolism of Candida boidinii KDI was compared on media containing methanol with bicarbonate and without it. The presence of carbon dioxide stimulated the activity of methanol oxidase, formaldehyde dehydrogenase, hexulose phosphate synthase and particularly carboxylases of pyruvate and phosphoenol pyruvate. At the same time, the activity of formate dehydrogenase, citrate synthase and isocitrate lyase decreased. Therefore, carbon dioxide produces a significant effect on methylotrophic metabolism of Candida boidinii KDI and is actively involved in biosynthetic processes.

Bicarbonates↗
PubMedDate not supplied

[Mechanism of methane oxidation by intact cells of obligate methylotrophs].

Ethane and propane were found to be competitive inhibitors of methane oxidation. Obligate methylotrophs can oxidize ethane only in the presence of methane, i.e. co-oxidation of ethane takes place. Studies on the kinetics of simultaneous oxidation of ethane and methane have shown that their oxidation is catalysed by one and the same enzyme system, within one and the same enzyme active site; therefore, the absolute substrate specificity is absent. The reactions of methane and ethane oxidation are coupled since ethane can be oxidized only after the reduced coenzyme had been provided by the reaction of methane oxidation.

Ethane↗
PubMedDate not supplied

[The effect of long-acting radiation on the diversity of heterotrophic bacteria in the soils of a 10-kilometer area around the Chernobyl Atomic Electric Power Station].

The catastrophe at Chernobyl Atomic Power Station (ChAPS) of 1986 has created a natural model for studying the after-effects of prolonged action of radiation on the biota. Our work is aimed to estimate the variability of heterotrophic bacteria in the soil of 10-km zone of ChAPS which have formed as affected by prolonged action of radiation, as well as to create the corresponding collection of bacteria. Microbiological analysis of soils was carried out in 1993-1994 (in spring, summer, autumn), allowing for bacteria destroying different organic substance (in soil). It is shown that in the surface layer of soils (at the depth of 0-2 cm) the total number of cells of heterotrophic bacteria as well as the number of found species of bacteria is considerably less than in the control samples. Atypical distribution of bacteria in the soil profile was established. Indices of the species diversity of bacteria in these soils permit one to consider that microbe content of soil of the 10-km zone of the ChAPS has become considerably less after the disaster at the ChAPS in 1986 and has not recovered by 1993. A collection of various physiological groups of bacteria including representatives of Methylobacterium genus has been created. They have been isolated from the soils of 10-km zone of the ChAPS for following genetic investigations.

Bacteria↗