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G S Kalacheva

Publications and source records attributed to G S Kalacheva.

29 records · Page 2Linked to original sources
PubMedDate not supplied

[Dynamics of activity of the key enzymes of polyhydroxyalkanoate metabolism in Ralstonia eutropha].

The dynamics of accumulation of polyhydroxybutyrate (PHB) and the activities of the key enzymes of PHB metabolism (beta-ketothiolase, acetoacetyl-CoA reductase, PHA synthase, D-hydroxybutyrate dehydrogenase, and PHA depolymerase) in the hydrogen bacterium Ralstonia eutropha B5786 were studied under various conditions of carbon nutrition and substrate availability. The highest activities of beta-ketothiolase, acetoacetyl-CoA reductase, and PHA synthase were recorded at the stage of acceleration of PHB synthesis. The activities of enzymes catalyzing PHB depolymerization (PHB depolymerase and D-hydroxybutyrate dehydrogenase) were low, being expressed only at stimulated endogenous PHB degradation. The change of carbon source (CO2 or fructose) did not cause any marked changes in the time course of enzyme activity.

Acetyl-CoA C-Acyltransferase↗
PubMedDate not supplied

[The synthesis of hydroxybutyrate and hydroxyvalerate copolymers by the bacterium Ralstonia eutropha].

The paper deals with the study of the synthesis of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) copolymers by the bacterium Ralstonia eutropha B-5786 grown under different carbon nutrition conditions (growth on carbon dioxide, fructose, and CO2-valerate and fructose-valerate mixtures). The parameters to be analyzed included the yield of biomass, the yield, synthesis rate, and composition of copolymers, the activity of the key enzymes of polyhydroxyalkanoate (PHA) synthesis (beta-ketothiolase, acetoacetyl-CoA reductase, and PHA synthase), the maximum tolerable concentration of valerate to the bacterium, and the conditions that govern the incorporation of hydroxyvalerate to copolymers. This allowed the relationship between cultivation conditions and the proportion of monomers in the copolymers to be deduced. We were able to synthesize a range of 3HB/3HV copolymers and found that the thermal characteristics and the degree of crystallinity of these copolymers depend on the molar fraction of 3HV.

Acetyl-CoA C-Acyltransferase↗
PubMedDate not supplied

[Physiological and biochemical characteristics and capacity for polyhydroxyalkanoates synthesis in a glucose-utilizing strain of hydrogen-oxidizing bacteria, Ralstonia eutropha B8562].

The physiological, biochemical, genetic, and cultural characteristics of the glucose-utilizing mutant strain Ralstonia eutropha B8562 were investigated in comparison with the parent strain R. eutropha B5786. The morphological, cultural, and biochemical characteristics of strain R. eutropha B8562 were similar to those of strain R. eutropha B5786. Genetic analysis revealed differences between the 16S rRNA gene sequences of these strains. The growth characteristics of the mutant using glucose as the sole carbon and energy source were comparable with those of the parent strain grown on fructose. Strain B8562 was characterized by high yields of polyhydroxyalkanoate (PHA) from different carbon sources (CO2, fructose, and glucose). In batch culture with glucose under nitrogen limitation, PHA accumulation reached 90% of dry weight. In PHA, beta-hydroxybutyrate was predominant (over 99 mol %); beta-hydroxyvalerate (0.25-0.72 mol %) and beta-hydroxyhexanoate (0.008-1.5 mol %) were present as minor components. The strain has prospects as a PHA producer on glucose-containing media.

Culture Media↗
PubMedDate not supplied

[Biochemical quality assessment of broiler production using a hydrogen bacteria biomass in the diet].

The authors studied the biochemical composition of the meat of broilers, eggs, liver and muscles of laying hens of 3 generations on a 5, 10, 25, 50 and 100% (broilers), 10 and 20% (laying hens) replacement of the animal protein quota in the diet by protein obtained from the hydrogen bacteria Alcaligenes eutrophus L-1. No deterioration of the quality of the produce was found from the standpoint of the main biochemical parameters.

Alcaligenes↗
PubMedDate not supplied

[Chufa (Cyperus esculentus) as a source of vegetable fats in a sealed life-support system].

The cultivation schemes, productivity, total biochemical, lipid in particular, composition of nodules of chufa (Cyperus esculentus) were studied, using a phytotron. Upon continuous illumination chufa yielded a high total productivity and a satisfactory coefficient of economic effectiveness (not less than 50%). Chufa nodules have an optimal ratio of proteins, carbohydrates and fats containing essential fatty acids. To meet man's requirements for vegetable oils and essential fatty acids, it is necessary to produce daily 150--200 g dry chufa nodules which are quite acceptable as a dietary ingredient.

Carbohydrates↗
PubMedDate not supplied

[Fatty acid makeup changes in the luminescent bacteria, Photobacterium mandapamensis, in periodic cultivation].

The fatty acid composition of the luminescent bacterium Photobacterium mandapamensis and its spontaneous dark mutant was studied in dynamics. Lipids of the both strains extracted with a methanol -- chloroform mixture contained the following fatty acids: lauric, tridecanoic, myristic, tetradecenic, pentadecanoic, pentadecenic, palmitic, palmitoleic, heptadecanoic, C17-cyclopropanoic, stearic, octadecenic, and nonadecanoic. The content of palmitoleic acid was the highest (57% of the total). Not all of the acids changed their content in the same direction during batch cultivation of the luminescent and dark strains. The content of palmitoleic acid fell to 49.2% of the total in the luminescent culture at the point of its maximal luminescence, but it increased to 63.8% in the dark strain at the corresponding growth phase.

Culture Media↗
PubMedDate not supplied

[Lipids of the luminescent bacteria Photobacterium mandapamensis].

The composition of lipids was studied in the luminescent bacterium Photobacterium mandapamensis under the conditions of maximal luminescence. The synthesis of total lipids and poly-beta-hydroxybutyric acid (PHBA) was investigated in dynamics under the conditions of batch cultivation. The major class of lipids was polar lipids (84.3%) represented by phospholipids (phosphatidyl ethanolamine, phosphatidyl glycerol, cardiolipin, lysocardiolipin, lysophosphatidyl ethanolamine) and a minor nonidentified phospholipid. The fraction of neutral lipids was represented mainly by free fatty acids (about 5%), tri- and diglycerides (in trace amounts), and two nonidentified classes, apparently, hydrocarbons and waxes. A correlation was established between the luminescence of the bacterium and the content of PHBA.

Hydroxybutyrates↗
PubMedDate not supplied

[Growth of hydrogen bacteria inhibited by carbon monoxide].

The growth of the hydrogen bacterium Alcaligenes eutrophys Z-1 was studied during inhibition by carbon monoxide in turbidostat. The specific growth rate of the bacterium was shown to depend on the concentration of CO in the gaseous phase. The deceleration of the cultural growth during inhibition by CO was accompanied with a decrease of economic coefficients with respect to oxygen and hydrogen. At a CO concentration of 10%, the specific growth rate of the bacterium was 0.25 hr-1 (mu) and the coefficient for utilizing the energy of hydrogen oxidation was 19.6% (eta); at a CO concentration of 20%, mu was 0.18 hr-1 and eta was 14.2%; at a CO concentration of 30%, mu was 0.07 hr-1 and eta was 10.2%. The deceleration of the cultural growth caused by inhibition with CO was not accompanied by changes in the synthesis of nitrogen containing and reserve substances in A. eutrophys Z-1. This strain of hydrogen bacteria was found to be resistant against extraneous microflora during inhibition with CO.

Alcaligenes↗
PubMedDate not supplied

[Lipid composition of carboxydobacteria].

The composition of lipids was studied in three strains of carboxydobacteria, viz. Seliberia carboxydohydrogena Z-1062, Pseudomonas gazotropha Z-1156 and Comamonas compransoris Z-1155. The content of lipids extracted with an alcohol--chloroform mixture varied in these strains from 9 to 13.2%. The main classes were phospholipids (from 62.6 to 77.2% of the overall lipid content). The major phospholipids were phosphatidyl ethanolamine and phosphatidyl choline. Moreover, the strains Z-1062 and Z-1156 contained three unidentified phospholipids which constituted 40 and 20% of the total content respectively. The neutral lipids of the carboxydobacteria comprised diglycerides, triglycerides, free fatty acids, methyl esters of fatty acids and a number of compounds which were not identified. The fatty acids of the strains were represented by saturated, monoene and cyclopropanoic acids. The main acids were palmitic, palmitolenic, C17-cyclopropanoic, stearic and octadecenic acids. Polar lipids differed from neutral lipids in their fatty acid composition. The fatty acid composition of firmly bound lipids was characterized by a high degree of saturation, the absence of cyclopropanoic acids and the presence of two unidentified acids that were not found in free lipids; apparently, they belonged to hydroxy acids.

Bacteria↗
PubMedDate not supplied

[Inclusion of chufa in the human diet as a source of polyunsaturated fatty acids].

In 2 experiments lasting 30 days each with participation of 6 volunteers the possibility of daily consumption in the diet of chufa in an amount allowing for minimal requirement of the organism in polyunsaturated fatty acids was studied. The experimental food ration accorded with individual requirements in its basic components. None of the participating volunteers demonstrated any untoward deviations of objective and subjective nature in their health status. For a month chufa was introduced daily at the rate of 1.7 g per kg of body weight.

Blood Cell Count↗