PubMed Health⌕ Search

Biomedical subjects

G S Kalacheva

Publications and source records attributed to G S Kalacheva.

At least 19 recordsLinked to original sources
PubMed2006

Physiological-biochemical properties and the ability to synthesize polyhydroxyalkanoates of the glucose-utilizing strain of the hydrogen bacterium Ralstonia eutropha B8562.

Physiological-biochemical, genetic, and cultural properties of the glucose-utilizing mutant strain Ralstonia eutropha B8562 have been compared with those of its parent strain R. eutropha B5786. It has been shown that growth characteristics of the strain cultured on glucose as the sole carbon and energy source are comparable with those of the parent strain. Strain B8562 is characterized by high polyhydroxyalkanoate (PHA) yields on different carbon sources (CO(2), fructose, and glucose). PHA accumulation in the strain batch cultured on glucose under nitrogen deficiency reaches 90 %. The major monomer in the PHA is beta-hydroxybutyric acid (more than 99 mol %); the identified minor components are beta-hydroxyvaleric acid (0.25-0.72 mol %) and beta-hydroxyhexanoic acid (0.08-1.5 mol %). The strain is a promising PHA producer on available sugar-containing media with glucose.

Biotechnology↗
PubMed2006

[Influence of different methods of cooking of hunchback salmon on contents of polyunsaturatedfatty acids].

Composition and contents of fatty acids in hunchback, fresh, boiled, fried, roasted and boiled in a small amount of water were determined. It was found, that absolute contents of essential polyunsaturated fatty acids--eicosapentaenoic (EPA) and docosahexaenoic (DHA) decreased significantly only in the process of frying. Sum ratio of omega3/omega6 acids was dietetically more favorable in the roasted and fried fish.

Animals↗
PubMed2003

Volatile metabolites of higher plant crops as a photosynthesizing life support system component under temperature stress at different light intensities.

The effect of elevated temperatures of 35 and 45 degrees C (at the intensities of photosynthetically active radiation 322, 690 and 1104 micromoles m-2 s-1) on the photosynthesis, respiration, and qualitative and quantitative composition of the volatiles emitted by wheat (Triticum aestuvi L., cultivar 232) crops was investigated in growth chambers. Identification and quantification of more than 20 volatile compounds (terpenoids--alpha-pinene, delta 3 carene, limonene, benzene, alpha- and trans-caryophyllene, alpha- and gamma-terpinene, their derivatives, aromatic hydrocarbons, etc.) were conducted by gas chromatograph/mass spectrometry. Under light intensity of 1104 micromoles m-2 s-1 heat resistance of photosynthesis and respiration increased at 35 degrees C and decreased at 45 degrees C. The action of elevated temperatures brought about variations in the rate and direction of the synthesis of volatile metabolites. The emission of volatile compounds was the greatest under a reduced irradiation of 322 micromoles m-2 s-1 and the smallest under 1104 micromoles m-2 s-1 at 35 degrees C. During the repair period, the contents and proportions of volatile compounds were different from their initial values, too. The degree of disruption and the following recovery of the functional state depended on the light intensity during the exposure to elevated temperatures. The investigation of the atmosphere of the growth chamber without plants has revealed the substances that were definitely technogenic in origin: tetramethylurea, dimethylsulfide, dibutylsulfide, dibutylphthalate, and a number of components of furan and silane nature.

Air Pollution, Indoor↗
PubMed2003

Production of purified polyhydroxyalkanoates (PHAs) for applications in contact with blood.

Samples of olyhydroxyalkanoates (PHAs), polyhydroxybutyrate (PHB) and copolymers poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) with 4 and 18 mol% hydroxyvalerate, synthesized by the bacteria Ralstonia eutropha B5786, were investigated. PHA films in contact with blood did not activate the hemostasis system at the level of cell response, but they did activate the coagulation system and the complement reaction. To detect biologically-active components in the PHAs, a detailed analysis of the composition of the polymers was conducted. Gas chromatography-mass spectrometry revealed long-chain fatty acids (FAs) in the tested PHAs. Their total concentration in the polymer ranged from tenths of mol% to 2-3 mol%, depending on the purification method. C16:0 constituted the largest proportion, up to 70%. Of the long-chain hydroxy acids, only beta-OH-C14:0 was detected and it did not exceed 0.06 mol%. The analysis of the hemocompatibility properties of the PHAs purified by a specialized procedure, including the quantitative and morphological estimation of platelets adherent to the surface of polymer films, the plasma recalcification time and complement activation studies, indicated that PHB and PHBV can be used in contact with blood. It has been found out that the lipopolysaccharides of bacteria producing PHAs, which contain mostly long-chain hydroxy acids, can be the factor activating the hemostasis systems. Thus, the technology of PHA purification must satisfy rather stringent specific requirements.

Biocompatible Materials↗
PubMed2002

Autotrophic synthesis of polyhydroxyalkanoates by the bacteria Ralstonia eutropha in the presence of carbon monoxide.

It has been found that the carbon monoxide (CO)-resistant strain of the hydrogen bacteria Ralstonia eutropha B5786 is able to synthesise polyhydroxyalkanoates (PHAs) in the presence of CO under autotrophic conditions. This strain, grown on model gas mixtures containing 5-25% CO (v/v), accumulates up to 70-75% (of absolutely dry matter) PHA, without significant variation in the yield coefficient on hydrogen. No suppression of the activities of the key enzymes of PHA synthesis ( beta-ketothiolase, acetoacetyl-CoA-reductase, butyrate dehydrogenase and poly-3-hydroxybutyrate synthase) was recorded. The PHA synthesised is a co-polymer containing mostly beta-hydroxybutyrate (more than 99 mol%) with trace amounts of beta-hydroxyvalerate. The investigated properties of the polymer (molecular weight, crystallinity, temperature characteristics) do not differ from those of the polymer synthesised on electrolytic hydrogen.

Carbon Monoxide↗
PubMedDate not supplied

[Lipids from the green algae Botryococcus during staged growth in batch mode].

The lipid fraction of the green alga Botryococcus cultured in a batch mode was found to contain polar lipids (more than 50% of the total lipids), di- and triacylglycerides, steroids and their esters, free fatty acids, and hydrocarbons. In senescent culture, the content of polar lipids somewhat decreased and that of triacylglycerides increased by more than four times. The content of hydrocarbons in the algal biomass did not exceed 0.9% and depended little on the culture age. Intracellular lipids contained saturated and unsaturated (mono-, di-, and trienoic) fatty acids. The maximum content of C16:3 and alpha-C18:3 fatty acids (up to 35% of the total fatty acids) was detected in the phase of active growth. The extracellular and intracellular lipids of the alga differed in the proportion of particular lipids and in the fatty acid pattern.

Chlorophyta↗
PubMedDate not supplied

[Characteristics of in vivo isolation of free fatty acids by prokaryotic and eukaryotic algae under elevated and reduced temperature].

The paper describes the composition of extracellular free fatty acids (FFAs) and intracellular fatty acids (FAs) in the enrichment cultures of the prokaryotic alga Spirulina platensis and the eukaryotic alga Chlorella vulgaris grown at optimal, supraoptimal, and suboptimal growth temperatures. With increasing growth temperature, the degree of unsaturation of the intracellular FAs of both algae decreased, while that of the extracellular FFAs of S. platensis increased. The composition of the extracellular FFAs of C. vulgaris practically did not depend on the growth temperature.

Chlorella↗
PubMedDate not supplied

[Autotrophic synthesis of polyalkanoates by Alcaligenes eutrophus in presence of carbon monoxide].

The CO-resistant strain B5786 of the hydrogen-oxidizing bacterium Alcaligenes eutrophus was found to be able to synthesize polyhydroxyalkanoates (PHAs) under the conditions of growth limitation by nitrogen deficiency (the factor that promotes PHA synthesis) and growth inhibition by carbon monoxide. The gas mixtures that contained from 5 to 20 vol% CO did not inhibit the key enzymes of PHA synthesis--beta-ketothiolase, acetoacetyl-CoA reductase, hydroxybutyrate dehydrogenase, and PHA synthase. In the presence of CO, cells accumulated up to 70-75 wt% PHA (with respect to the dry biomass) without any noticeable increase in the consumption of the gas substrate. Chromatographic-mass spectrometric analysis showed that the PHA synthesized by A. eutrophus is a copolymer containing more than 99 mol% beta-hydroxybutyrate and trace amounts of beta-hydroxyvalerate. The PHA synthesized under the conditions described did not differ from that synthesized by A. eutrophus cells from electrolytic hydrogen.

Alkanes↗
PubMedDate not supplied

[Volatile metabolites and external CO2 exchange of wheat cenoses under optimal conditions and thermal stress].

The effects of elevated temperature (35 and 45 degrees C) on photosynthesis, respiration, and both the qualitative and quantitative compositions of volatile emissions (VE) of wheat (Triticum aestuvum L. cultivar 232) cenoses at light intensities of 70, 150, or 240 W/m2 of photosynthetically available radiation (PAR) were studied. At a PAR of 240 W/m2, the thermal stabilities of photosynthesis and respiration increased at 35 degrees C and decreased at 45 degrees C. Elevated temperatures nonuniformly changed the rates and direction of VE syntheses. In this process, the highest increase in VE evolution was observed at 70 W/m2; the lowest, at 240 W/m2 and 35 degrees C. In addition, the concentrations and composition of VE during the repair period differed from the initial values.

Air↗
PubMedDate not supplied

[The effect of temperature on the lipid composition of Botryococcus].

The lipid composition of the green alga Botryococcus was studied at three different cultivation temperatures: suboptimal, optimal, and supraoptimal. Cultivation at the supraoptimal temperature was found to considerably inhibit the synthesis of nearly all intracellular lipids, except for triacylglycerides, and to influence their fatty acid composition. In particular, the content of trienoic fatty acids was significantly lower at the supraoptimal than at the optimal cultivation temperature. At the same time, the fatty acid composition of the extracellular lipids of the alga virtually did not depend on cultivation temperature.

Chlorophyta↗