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Biomedical subjects

V A Kratasyuk

Publications and source records attributed to V A Kratasyuk.

9 recordsLinked to original sources
PubMed2006

Redox compounds influence on the NAD(P)H:FMN-oxidoreductase-luciferase bioluminescent system.

A review of the mechanisms of the exogenous redox compounds influence on the bacterial coupled enzyme system: NAD(P)H:FMN-oxidoreductase-luciferase has been done. A series of quinones has been used as model organic oxidants. The three mechanisms of the quinones' effects on bioluminescence were suggested: (1) inhibition of the NADH-dependent redox reactions; (2) interactions between the compounds and the enzymes of the coupled enzyme system; and (3) intermolecular energy migration. The correlation between the kinetic parameters of bioluminescence and the standard redox potential of the quinones proved that the inhibition of redox reactions was the key mechanism by which the quinones decrease the light emission intensity. The changes in the fluorescence anisotropy decay of the endogenous flavin of the enzyme preparations showed the direct interaction between quinones and enzymes. It has been demonstrated that the intermolecular energy migration mechanism played a minor role in the effect of quinones on the bioluminescence. A comparative analysis of the effect of quinones, phenols and inorganic redox compounds on bioluminescent coupled enzyme systems has been carried out.

FMN Reductase↗
PubMed2003

Oxidative stress monitoring in biological samples by bioluminescent method.

The integral bioluminescent biotest with lyophilized fluorescent bacteria was used for monitoring of LPO processes in tissue extracts and serum of rats exposed to stress. A relationship between the content of MDA (LPO indicator) and fluorescence of bacteria was observed in all biological samples.

Animals↗
PubMed2002

Estimation of energy of the upper electron-excited states of the bacterial bioluminescent emitter.

The hypothesis of activity of the upper electron-excited states of the bacterial bioluminescent emitter was verified using dye molecules as foreign energy acceptors. Six compounds were selected having fluorescent state energies ranging from 25,700 to 32,000 cm(-1) (anthracene, pyrene, 1.4-bis(5-phenyloxasol-2-yl)benzene (POPOP), p-bis(o-methylstyryl)benzene (MSB), 2-methoxy-naphtalene, p-terphenyl), exceeding that of the bioluminescent emitter (22,000 cm(-1)). Their absorption spectra do not overlap with the bioluminescence spectrum; the trivial light absorption and the intermolecular resonance S-S energy transfer were excluded. Bacterial bioluminescent spectra of the coupled enzyme system NADH:FMN-oxidoreductase-luciferase in the presence of MSB were presented as an example. The weak sensitized fluorescence of MSB was registered. The results obtained have confirmed the activity of the energetic precursor in the bacterial bioluminescence. Its energy can be located in the interval of 26,000-27,000 cm(-1).

Bacteria↗
PubMed2001

The use of bioluminescent biotests for study of natural and laboratory aquatic ecosystems.

A set of bioluminescent tests was developed to monitor water quality in natural and laboratory ecosystems. It consisted of four bioluminescent systems: luminous bacteria, coupled enzyme system NADH:FMN-oxidoreductase-luciferase and triplet enzyme systems with alcohol dehydrogenase and trypsin. The set of biotests was applied for a small forest pond (Siberia, Russia), laboratory microecosystems polluted with benzoquinone and a batch culture of blue-green algae. Thereby effects of natural water compared to those of models of heavy pollution and "bloom" of blue-greens on the bioluminescent tests were revealed. The set of biotests was not affected by a natural seasonal variability of water quality in the unpolluted pond, but responded to the heavy pollution and the "bloom" of blue-greens. The set of biotests could be recommended as the alarm test to control the acute toxicity of natural water bodies.

Benzoquinones↗
PubMedDate not supplied

Practical enzymology course based on bioluminescence.

We describe our experience with laboratory courses in enzymology based on the phenomenon of bioluminescence. The soluble and immobilized enzymes of luminous bacteria are used and the practical enzymological course consists of four main courses: (1) training in measuring the activities of soluble and immobilized enzymes; (2) the investigation of kinetic characteristics (kinetic constants) and enzyme-substrate and enzyme-inhibitor interactions in the bacterial bioluminescent reaction; (3) The testing of physico-chemical characteristics of enzymes (pH, temperature, ion strength, etc.); (4) the effect of inhibitors on enzymes. Training is possible in groups of about ten persons. Our practice work has been introduced in the biological, pedagogical and physical departments of Krasnoyarsk State University. Students of the pedagogical department have created a popular and interesting series of laboratory works for high school children aged 14-17 years.

Biochemistry↗
PubMedDate not supplied

Bioluminescent water quality monitoring of salt lake Shira.

The coupled bioluminescent enzyme system luciferase-NADH:FMN-oxidoreductase was used as a biotest in ecological monitoring of the health resort salt lake Shira (South Siberia, Russia). The technique was adapted to saltwater conditions. Bioluminescence kinetic parameters sensitive to pollutants were determined. Conditions for the use of bacterial bioluminescence biotests in salty environmental media were established.

Environmental Monitoring↗
PubMedDate not supplied

Bioluminescent method to determine non-specific endotoxicosis in therapy.

The possibility of using a bioluminescence method for measuring endotoxicosis during therapy has been investigated. Results of our experiments shown that a bioluminescence method can be used as a reliable criterion to monitor the course of disease for patients with bronchitis, ulcerous disease or chronic colecystitis. Assays using both soluble and immobilized reagents are possible. This method does not reveal differences in patients with sepsis, hepatocirrhosis or oncology. The methods are highly sensitive, rapid and simple and allow quantitative determination of the degree of seriousness of illness and estimation of the severity of a patient's condition. At present the test is used to find substances responsible for the toxic state.

Bacteremia↗
PubMedDate not supplied

Effect of quinones and phenols on the triple-enzyme bioluminescent system with protease.

The study addressed the effects of redox-active compounds on trypsin activity. Series of organic oxidizers (quinones) and reducers (phenols) were chosen as model redox-active compounds. Trypsin activity was quantified by bioluminescent technique. Interactions of these compounds with trypsin were studied by fluorescent and light absorption methods. Luminescence intensity decay constants in the reduced nicotinamidadeninedinucleotide (NADH): flavinmononucleotide (FMN)-oxidoreductase (R)-luciferase (L)-trypsin (T) (R + L + T) triple-enzyme system were calculated and compared in the presence of different concentrations of quinones and phenols. The triple-enzyme system was shown to be sensitive to quinones and not sensitive to phenols. It has been found that the effects produced by quinones on the coupled enzyme system (R + L) and on the trypsin molecule (T) are not related. The conclusions were extrapolated to the properties of other proteases and antiproteases.

Endopeptidases↗