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Biomedical subjects

V I Kiselev

Publications and source records attributed to V I Kiselev.

At least 19 recordsLinked to original sources
PubMed1991

DNA interpolyelectrolyte complexes as a tool for efficient cell transformation.

A tool was developed for enhancement of plasmid penetration into an intact cell, based on increasing DNA hydrophobicity via inclusion into a soluble interpolyelectrolyte complex (IPC) with polycations. The characteristics of formation of DNA IPC with synthetic polycations [poly(N-ethyl-4-vinylpyridinium)bromide (PVP) and PVP modified with 3% of N-cetyl-4-vinylpyridinium units (PVP-C)] were studied using ultracentrifugation and polyacrylamide gel electrophoresis methods. The conditions were established under which the mixing of DNA and polycation aqueous solutions results in the self-assembly of soluble IPC species. Incorporation of DNA into IPC results in the enhancement of DNA binding with isolated Bacillus subtilis membranes. A considerable increase in the efficiency of transformation of B. subtilis cells with pBC16 plasmid resulted from incorporation of the plasmid into the IPC with PVP and CVP.

Bacillus subtilis↗
PubMed1991

Ca(2+)-dependent phosphorylation of synapsin I as a possible regulatory mechanism of neurosecretion.

Phosphorylation of homogeneous synapsin I isolated from human brain by Ca2+, phospholipid-dependent protein kinase (protein kinase C) from the same source was studied. The inhibitory effect of calmodulin on this process was demonstrated. The kinetics of activation of synapsin I phosphorylation by acidic phospholipids, phosphatidylserine and phosphatidylinositol, in the absence and presence of phosphatidylinositol-4,5-bisphosphate and diacylglycerol was compared. The proteolytic effect of degradation of the synapsin I molecule phosphorylated by Ca2+, calmodulin-dependent protein kinase II was revealed. No proteolysis of synapsin phosphorylated under similar conditions either by protein kinase C or cAMP-dependent protein kinase was detected. In view of the process specificity, the physiological significance of the observed effect is suggested. The inter-relationship between two ways of neurosecretion regulation is discussed: an earlier known, conventional way, mediated by synapsin I phosphorylation by Ca2+, calmodulin-dependent protein kinase II, and another one, mediated by synapsin I phosphorylation by protein kinase C. The modulating role of polyphosphoinositides in the PK C-dependent way of regulation is considered.

Brain↗
PubMed1991

Hydrophobized antiviral antibodies and antisense oligonucleotides.

A method of suppressing virus reproduction in cells has been proposed. The approach consists of affecting the cells with antiviral antibodies artificially hydrophobized with fatty acid residues. Reproduction of influenza viruses in MDCK cells and respiratory-synticial virus in HeLa cells was used as a model to demonstrate that poly- and monoclonal antibodies, modified by 1 or 2 stearic acid residues, are potent, unlike the non-modified antibodies, at inhibiting viral reproduction. The observed phenomenon is apparently due to penetration of hydrophobized antibodies into the cells. Thus, in particular, considerable antiviral activity is exhibited by monoclonal antibodies against NP-protein of influenza virus, which is an antigen accessible to antibodies only inside the infected cells. Hydrophobized antibodies do not affect the kinetics of viral protein synthesis; they block the virus withdrawal from the cells, probably by interfering with the assembling and budding of virus particles. To enhance penetration of oligonucleotides ("oligos") into cells, chemical modification of the former at the 5'-end phosphate group by fatty radicals has been suggested. The undecanol-modified oligo namely an oligo complementary to the protein binding sites located at the influenza virus polymerases encoding RNA, was synthesized using a DNA-synthesator. The above modified oligo effectively suppressed the influenza A/PR8/34 virus reproduction and inhibited synthesis of the virus-specific proteins in MDCK cells. The non-modified antisense oligo and the modified nonsense oligo did not affect the virus development under the same conditions.

Animals↗
PubMed1991

[Neuroendocrine regulation under maximal and subjectively optimal physical loads].

The responses of neuroendocrine system to maximum and subjective-optimum physical loading were found to be similar in young men and characterized by activation of adrenocortical, somatotropic and thyroid functions, particularly under maximum loading. The subjective-optimum loading was dosed out by the subjects themselves, differentiated individually and averaged 62% of the maximum oxygen consumption. The parameters of subjective-optimum physical loading were close to the threshold level necessary to stimulate neuroendocrine system and ensure an increase of somatotropine, cortisole, thyroxine and aldosterone concentration in the blood.

Adolescent↗
PubMed1990

A new class of antivirals: antisense oligonucleotides combined with a hydrophobic substituent effectively inhibit influenza virus reproduction and synthesis of virus-specific proteins in MDCK cells.

To enhance the penetration of oligonucleotide ('oligo') into cells, the oligo was combined with the hydrophobic undecyl residue. Using the 'DNA-synthesator', we synthesized oligo, complementary to the loop-forming site of the RNA, encoding polymerase 3 of the influenza virus (type A), and combined it with the undecyl residue added to the 5' terminal phosphate group. It was found that the modified oligo effectively suppresses the influenza A/PR8/34 (H1N1) virus reproduction and inhibits the synthesis of virus-specific proteins in MDCK cells. Under the same conditions, the non-modified antisense oligo and modified nonsense oligo did not affect the virus development.

Animals↗
PubMed1990

Calmodulin-dependent enzymes as a target of staphylococcal enterotoxin A.

The response of lymphoid and nerve cells to the action of SEA has been investigated. It has been established that the toxin acts as a mitogen with respect to resting cells and suppresses the DNA biosynthesis in proliferating cells. Interaction of SEA with the systems of second messengers in lymphoblastoid cells has been studied. The results obtained suggest a mechanism of the antiproliferative action of SEA on these cells. Studies on the structural organization of the toxin molecule have revealed that the latter contains a polypeptide (BacM) capable of activating calmodulin-dependent enzymes both in the presence and absence of Ca2+. These findings permit us to assume that the cytostatic effect of SEA is conditioned by the formation of BacM and phosphorylation of elongation factor 2.

Adenylyl Cyclases↗
PubMed1990

Amplification of DNA sequences of Epstein-Barr and human immunodeficiency viruses using DNA-polymerase from Thermus thermophilus.

Using thermophilic DNA-polymerase from Thermus thermophilus we have amplified by polymerase chain reaction (PCR) specific DNA sequences of Epstein-Barr virus (EBV) and human immunodeficiency virus (HIV). DNA-polymerase from Thermus thermophilus (molecular mass of 80-86 kDa) differs in its physico-chemical properties from DNA-polymerase from Thermus aquaticus (molecular mass of 62-68 kDa). To amplify the specific EBV DNA sequence, oligonucleotide primers for the virus replicon region (oriP region) were used. As a result of amplification, a specific 405-bp DNA fragment was produced.

Base Sequence↗
PubMed1990

[Expression of Staphylococcus aureus enterotoxin A gene in heterologous systems].

The genomic library of Staphylococcus aureus genes on the plasmid vector pSL5 has been constructed. The library contains a 2.5 kb HindIII DNA fragment including the gene for enterotoxin A. The entA gene on the high copy number plasmids in the Escherichia coli cells deficient in proteolysis determines the synthesis of enterotoxin A in the amounts comparable to the ones in the parent strain Staphylococcus aureus FRI 722(H).

Bacillus subtilis↗
PubMed1990

Effective inhibition of viral reproduction by hydrophobised antiviral antibodies.

A method is proposed for the inhibition of viral reproduction in cells by means of fatty-acylated antiviral antibodies which, in contrast to the unmodified antibodies, have the ability to enter the cells. The potential of this technique is demonstrated in experiments involving inhibition of the reproduction of various strains of influenza virus and respiratory syncytial virus.

Acylation↗
PubMed1989

Fatty acid acylated antibodies against virus suppress its reproduction in cells.

A method for suppression of virus reproduction in cells using fatty acylated antiviral antibodies, which in contrast to non-modified antibodies are capable of intracellular penetration, has been suggested. The addition of stearoylated antiviral antibodies to influenza A/Chili virus-infected cells causes a 100-fold suppression of virus reproduction. Non-modified antibodies do not produce any effect on virus reproduction.

Acylation↗
PubMed1989

[Regulation of proteolytic processes using antisense RNA genes htpR and lon of Escherichia coli in hetero- and homologous genetic systems].

Possibility of correction of proteolytic processes in cells of Escherichia coli and Pseudomonas aeruginosa has been studied. For this purpose recombinant plasmids directing the synthesis of antisense RNAs were constructed. In Ps. aeruginosa the synthesis of htpR antisense RNA resulted in 2.5-fold reduction of the intensity of degradation of 3H-puromycin polypeptides under heat shock conditions. An antisense RNA complementary to the 5'- end of E. coli lon gene decreased the same index to the level observed in lon- mutants. Genes homologous to htpR and lon genes of E. coli were found in Pseudomonas: bacteria in hybridisation experiments. This finding suggests that the genetic system of heat shock in these microorganisms is organized in a similar manner.

Autoradiography↗
PubMed1989

[Experimental study of the antitumor properties and mechanism of action of kortifen].

Cortiphen, a newly developed hormonal cytostatic ester of 11-desoxy-17 alpha-hydroxycorticosterone and chlorophenacyl, is described. It was studied in transplantable, spontaneous and induced tumors of 7 sites: hemoblastosis (5), hepatoma (3), mammary gland (5), lung (2), gastrointestinal tract (3), sarcoma (2) and melanoma. Practically all the tumors were shown to respond to cortiphen action. Among the antitumor effects of the drug were: long-term inhibition of tumor growth or tumor regression, contribution to longer survival, antimetastatic action and sustained action during repeated courses of administration. Cortiphen was found to interact with glucocorticoid receptors in both animal and human tumors. The role of the hormonal component of the drug's molecule in the realization of its antitumor effect is discussed.

Animals↗
PubMed1988

Regulation of proteolysis in Escherichia coli cells by antisense RNA of htpR gene.

A new vector has been constructed on the basis of plasmid pCQV2 containing thermoinducible regulatory elements of bacteriophage lambda. The vector makes it possible to combine an inducible synthesis of foreign proteins with negative control of intracellular proteolysis. The principle employed for the construction of the plasmid implies the regulation of gene expression by antisense RNAs. In the SalI restriction site of pCQV2 a fragment of htpR gene encoding the N-terminal region of the polypeptide has been cloned in opposite orientation. At 42 degrees C transcription from the PR promoter of the plasmid is initiated, resulting in the synthesis of htpR antisense RNA. The product of htpR gene is known to be responsible for positive regulation of transcription of at least three genes encoding proteases lon, groEL, and groES. Inactivation of the htpR transcript due to its complementary pairing with the antisense RNA hinders the synthesis of proteases under temperature stress conditions, thus leading to the reduction in the rate of proteolysis of abnormal proteins.

Escherichia coli↗