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Biomedical subjects

V A Kovalenko

Publications and source records attributed to V A Kovalenko.

14 recordsLinked to original sources
PubMed1992

Trans-diamminedichlorplatinum (II)-modified probes for detection of picogram quantities of DNA.

A novel simple nonradioactive method for detection of specific nucleotide sequences has been developed. This method consists of the hybridization of a target DNA with a DNA probe modified with trans-diamminedichlorplatinum(II) (trans-DDP) followed by detection of DNA/DNA hybrids with affinity-isolated anti-DNA-trans-DDP antibodies and poly-horseradish peroxidase-protein A conjugate. Major advantages of this approach are the low cost and the extreme simplicity of the labeling procedure, which involves only mixing of the reagents. The sensitivity of the proposed technique is sufficient to detect 0.8 pg of DNA in Southern blot hybridization and 25 fg in dot hybridization and permits colony screening.

Antibodies↗
PubMed1992

[A new immunochemical method for detecting substance P receptors based on the biotin-streptavidin system].

A novel method for detecting the membrane receptors of Substance P (SP) has been developed. The method does not require radioactive derivatives of SP and is based on quantitation of specifically bound biotinylated SP (Bt-SP), the analysis being performed after destruction of the ligand-receptor complex in acidic conditions and Bt-SP extraction into solution. The acidic extract from the Bt-SP-membrane complex after neutralization is added to immulon microELISA plate coated with affinity purified anti-SP-antibodies. The sensitivity of subsequent detection of Bt-SP enhances by using a new type of the streptavidin conjugate with a polymeric form of horseradish peroxidase. Enzyme immunoassay conditions were optimized using [125I]-labelled SP derivative. The developed method allows the determination of femtomoles of SP in a sample and has a sensitivity comparable to that of radioligand analysis.

Amino Acid Sequence↗
PubMed1991

[Lipid peroxidation and microviscosity of erythrocyte membranes in patients with schizophrenia].

During examination of 27 patients with schizophrenia, a study was made of the processes of free radical lipid oxidation. It has been established that in patients with schizophrenia, the processes of lipid peroxidation are activated and microviscosity of erythrocytic membranes is increased. The rise of microviscosity of erythrocytic membranes is attended by an increase of cholesterol content and of the amount of sialic acids of gangliosides involved in the formation of the superficial charge of erythrocytes. The authors hold that the changes discovered may cause functional destabilization of erythrocytic membranes, which may play a definite part in the development of hypoxia in schizophrenic patients.

Adolescent↗
PubMed1990

Isolation and properties of the alpha-latrotoxin receptor.

The receptor protein of alpha-latrotoxin (alpha LTx, a neurotoxin with 'pure' presynaptic action isolated from black widow spider venom), was solubilized by Triton X-100 from bovine brain membranes and purified by affinity chromatography on alpha LTx-Sepharose. The purified receptor preparation contained four major polypeptides of molecular masses 200 (alpha), 160 (alpha'), 79 (beta) and 43 (gamma) kd according to SDS electrophoresis with molecular ratio alpha 1 alpha' 1 beta 2 gamma 2. The alpha- and alpha'-subunits are glycoproteins binding to wheat germ lectin and can be separated under non-denaturing conditions by anion exchange chromatography. Purified to homogeneity, both of them, though differing in the carbohydrate composition, retain the alpha LTx-binding activity and give closely related peptide maps. Anti-alpha antibodies recognize the alpha'-subunit as well. These results suggest that alpha LTx receptor is present in purified preparations in two very close forms containing the alpha- or alpha'-subunit. Beta and gamma proteins do not specifically bind alpha LTx and their physiological role is unclear. They form a complex with solubilized alpha- and alpha'-subunits independently of alpha LTx presence. The receptor proteins were purified to homogeneity by high performance gel filtration in the presence of SDS, their amino acid composition was determined.

Amino Acid Sequence↗
PubMed1990

[Study of the receptor for black widow spider neurotoxin. I. Characteristics of membrane-bound and solubilized receptors from the bovine brain].

Iodine-125 labelled alpha-latrotoxin from the venom of Central Asia black widow spider Latrodectus mactans tredecimguttatus binds specifically to the bovine brain membrane receptor producing a stable slowly dissociating complex with Kd = 1.6 x 10(-10) M and Bmax = 0.5 pmol/mg protein. Treatment of the complex with alkaline high-salt buffer induces reversible dissociation of the bound toxin. The antitoxin polyclonal antibody does not increase the dissociation rate of the bound toxin. Wheat germ lectin as well as concanavalin A inhibit the toxin binding to the membrane receptor. The receptor is solubilized with ionic and non-ionic detergents, and methods of latrotoxin binding assay are developed. The solubilized receptor is shown to retain high affinity to toxin, its binding activity being stable but critically dependent on the presence of calcium ions. Chromatographic properties of the receptor suggest its glycoprotein nature.

Animals↗
PubMed1990

[Study of the receptor for black widow spider neurotoxin. II. Isolation and characteristics of the receptor from bovine brain membranes].

Biospecific sorbents for isolation of the latrotoxin receptor have been obtained and studied. Binding of the receptor components solubilized from the bovine cerebral cortex membrane to the immobilized toxin critically depends on the presence of calcium ions and the solution ionic strength. The procedure for semipreparative isolation of the highly active receptor preparation with Kd = 9 x 10(-10) M and Bmax = 0.9 nmol/mg has been developed. Binding activity of the isolated receptor is inhibited by heating as well as by proteases and denaturing agents. According to electrophoretic analysis in the presence of SDS the receptor complex contains protein components of molecular mass 200, 160, 79, 43 kDa, the former two being glycoproteins.

Animals↗
PubMedDate not supplied

[The effectiveness of lanthanide immunofluorescence and immunoenzyme analyses in differentiating viruses of the tick-borne encephalitis complex].

Comparison of the efficacy of time-resolved fluoroimmunoassay (TR-FIA) and two variants of enzyme immunoassay: conventional (EIA-1) and one using biotin-streptavidin system (EIA-2), in differentiation of viruses of the tick-borne encephalitis complex showed that, their specificity being similar, the TR-FIA method was 2-4 times as sensitive as EIA-2 and 8-32 times as sensitive as EIA-1. When the reactivity of the antigens was assessed by titers, the differentiating capacity was found to be similar and to depend upon the specificity of "sandwich"-forming antibodies and the sensitivity of the immunoassay. When the reactivity of the antigens was assessed by relative reactivity in 4 test systems of different compositions, the differentiating capacity of TR-FIA was higher than that of EIA-1 and EIA-2 which allowed additional differentiation of 2 groups of viruses on the basis of qualitative characteristics of reactivity.

Animals↗
PubMedDate not supplied

[The dynamics of the microorganism count of active sludge during the aerobic treatment of sewage].

Dynamics of the active sludge microorganism quantity is studied under different cultivation regimes. It is shown that quantity of microorganisms in different physiological groups depends on the specific growth rate, micro, determined by the dilution rate and biomass recirculation level. The results may be used for selecting optimal regime of the sewage treatment system functioning.

Aerobiosis↗