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Biomedical subjects

V I Kiselev

Publications and source records attributed to V I Kiselev.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1988

Use of cloned htpR gene of Escherichia coli to introduce htpR mutation into the chromosome.

A deletion htpR mutant of Escherichia coli has been constructed on the basis of site-directed mutagenesis. To this end, the chromosomal allele of htpR gene was substituted by a mutant allele introduced into the cell with a recombinant plasmid. The htpR mutant is characterized by a reduced level of proteolysis and therefore by a decreased rate of proteolytic degradation of RNA polymerase of bacteriophage T7. The mutation in htpR is linked with chloramphenicol resistance.

Alleles↗
PubMed1988

[Properties of thermostable HtpR-mutant of Escherichia coli].

A thermoresistant htpR mutant having a decreased level of proteolytic activity has been selected in E. coli strain K802 after the directed mutagenesis in vivo. The mutation results in the bacteriophage T7 RNA-polymerase stability, aminoglycosidephosphotransferase stability as well as in the decrease in the rate of proteolytic degradation of cytoplasmic proteins during the heat shock. The obtained mutant strain can, probably be used as a host for alien polypeptides production.

Adenosine Triphosphate↗
PubMed1988

[Integration of a plasmid into the Pseudomonas aeruginosa chromosome mediated by homologous DNA sequences].

The integrative vectors for Pseudomonas aeruginosa cells were constructed on the basis of the plasmid pSUP202. To construct the integrative vectors the fragments of chromosomal DNA mediating the homologous recombination were cloned in the plasmid. The possibility of cloning of different genes in the chromosomes of Pseudomonas aeruginosa cells was illustrated by KmR gene cloning.

Base Sequence↗
PubMed1988

htpR-like gene controls cell division and proteolysis in Pseudomonas aeruginosa.

As shown in hybridization experiments, the genome of Pseudomonas aeruginosa cells contains a htpR-like gene which controls the expression of heat shock genes in cells of Escherichia coli. By means of specially constructed plasmids, the synthesis of htpR antisense RNA has been found to disturb cell division and proteolytic processes in P. aeruginosa, suggesting the functional relationship of htpR genes in E. coli and Pseudomonas bacteria.

Cell Division↗
PubMed1987

[Directed mutagenesis of chromosomal genes of Escherichia coli in vivo: construction of RecA- and HtpR- mutants].

The deletions in Escherichia coli chromosomal genes recA and htpR were constructed using the site-directed mutagenesis techniques. The obtained RecA- mutants are UV-sensitive and have a phenotype defective for the homologous DNA recombination. HtpR- mutant is temperature sensitive for growth and deficient in intracellular proteolysis. As a result a HtpR- mutant seems to be a preferable candidate for attempting to synthesize efficiently any alien protein in Escherichia coli cells.

Chromosomes, Bacterial↗
PubMed1987

[Kanamycin sulfate--an inducer of recA gene in Escherichia coli].

Kanamycin sulphate causes the efficient induction of recA gene, being an inhibitor of protein synthesis. Kanamycin is not known to damage the DNA structure. Possibly, the antibiotic ability to induce the SOS-genes is explained by activation of endogenous nucleases activity or by the increase of "alarmone" synthesis, the latter playing the "trigger" role in derepression of SOS-operon.

Escherichia coli↗
PubMed1987

[Possible participation of vessel wall kinins in regulating blood vessel tonus].

Extracts of mammalian arterial walls revealed a kinin-like biological activity resistant against proteolytic inactivation with trypsin but not chymotrypsin. Bradykinin was chromatographically determined as kinin existing in extracts from the rat aorta. Kallidin was found as well as bradykinin in human vessels. Metabolism of vasoactive kinins in the vascular wall seems to take part in control of circulation and blood pressure.

Animals↗