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I A Smirnova

Publications and source records attributed to I A Smirnova.

At least 37 records · Page 2Linked to original sources
PubMed1986

The sodium cycle. I. Na+-dependent motility and modes of membrane energization in the marine alkalotolerant vibrio Alginolyticus.

Respiration, membrane potential generation and motility of the marine alkalotolerant Vibrio alginolyticus were studied. Subbacterial vesicles competent in NADH oxidation and delta psi generation were obtained. The rate of NADH oxidation by the vesicles was stimulated by Na+ in a fashion specifically sensitive to submicromolar HQNO (2-heptyl-4-hydroxyquinoline N-oxide) concentrations. The same amounts of HQNO completely suppressed the delta psi generation. Delta psi was also inhibited by cyanide, gramicidin D and by CCCP + monensin. CCCP (carbonyl cyanide m-chlorophenylhydrazone) added without monensin exerted a much weaker effect on delta psi. Na+ was required to couple NADH oxidation with delta psi generation. These findings are in agreement with the data of Tokuda and Unemoto on Na+-motive NADH oxidase in V. alginolyticus. Motility of V. alginolyticus cells was shown to be (i) Na+-dependent, (ii) sensitive to CCCP + monensin combination, whereas CCCP and monensin, added separately, failed to paralyze the cells, (iii) sensitive to combined treatment by HQNO, cyanide or anaerobiosis and arsenate, whereas inhibition of respiration without arsenate resulted only in a partial suppression of motility. Artificially imposed delta pNa, i.e., addition of NaCl to the K+ -loaded cells paralyzed by HQNO + arsenate, was shown to initiate motility which persisted for several minutes. Monensin completely abolished the NaCl effect. Under the same conditions, respiration-supported motility was only slightly lowered by monensin. The artificially-imposed delta pH, i.e., acidification of the medium from pH 8.6 to 6.5 failed to activate motility. It is concluded that delta mu Na+ produced by (i) the respiratory chain and (ii) an arsenate-sensitive anaerobic mechanism (presumably by glycolysis + Na+ ATPase) can be consumed by an Na+ -motor responsible for motility of V. alginolyticus.

Arsenates↗
PubMed1986

[Cationic control of the transcription of various genes in tumor cells].

Using ascite tumour cells (Ehrlich carcinoma, plasmacytoma MOPC-21, leukemia P-388, lympholeucosis NK/Ly) and bone marrow cells of intact rats, the possibility of regulation of transcription of a gene encoding 35S RNA via the alteration of the univalent cations Na+/K+ intracellular ratio was demonstrated. Gene 35S RNA was transcriptionally active within the range of 1 less than or equal to Na+/K+ less than 3 but was switched off at Na+/K+ less than 1. In synchronized Ehrlich carcinoma cells this gene was activated at the early steps of the mitotic cycle, when the cationic ratio was above 1. It was assumed that the so-called cationic mechanism of regulation of transcription predetermined the time and other of stimulation of certain genes in the course of the mitotic cycle and provided for the transcription of normally repressed genes as a result of malignant transformation.

Animals↗
PubMed1985

[Polynucleotide sequences in the DNA from leukemic cells forming RNAse-resistant complexes with polyuridylic acid].

RNAase-resistant complexes of poly(U): poly (dA) were obtained by hybridization of [3H] poly (U) with cellular DNA. Depending on the mode by hybrids treatment with RNAase, two types of (dA)-sites i. el, dA and poly (dA) sites with different homogeneity were identified. The amount of these sequences in the DNA isolated from normal cells of intact animals and from several types of leukemic cells was determined. Full identity of the dA-sites in normal tissue DNAs of the same animals and a statistically significant increase in their content in leukemic cells were demonstrated. Differences between DNAs of normal and leukemic cells vary widely, depending on the leukemia type.

Animals↗
PubMed1984

[Activation of cellular genes as affected by Rauscher leukemia virus].

The methods of hybridization in solution and blot hybridization have shown that the BALB/c mice spleen cells contain "silent" genes which can amplificate and change their structure following the infection by the Rauscher leukemia virus (RLV). The product of these gene activation is nuclear 35S RNA detectable by the comparative electrophoretic analysis of heterogeneous nuclear RNA of leukemic and normal cells. The expression of complete copies of 35S RNA was observed in nuclei of RLV-infected cells, while in cytoplasm this RNA is represented by incomplete copies. The expression of the sequences homologous to this 35 S RNA in normal mice spleen cells was not detected.

Animals↗
PubMed1984

[Effect of histone H5 on RNA synthesis in leukemic cells and on the translation process in vitro].

The effects of the erythrocyte-specific histone H5 from chicken erythrocytes on HnRNA synthesis in splenocytes of Rauscher virus-infected mice were studied. It was shown that histone H5 represses the synthesis of 35S RNA typical of the Rauscher virus-producing cells but does not influence the synthesis of other HnRNA fractions. The effects of H5 and other histones on the effectiveness of poly(U) translation in a cell-free system of wheat embryos were investigated. Structurally similar histones H1 and H5 exert the strongest inhibiting action on translation. It was assumed that the previously described antileukemic action of histone H5 is realized at the levels of transcription and translation.

Animals↗
PubMed1981

Fast stages of photoelectric processes in biological membranes. III. Bacterial photosynthetic redox system.

Chromatophores of photosynthetic bacteria Rhodospirillum rubrum, Rhodopseudomonas sphaeroides and Chromatium minutissimum were associated with a collodion film impregnated with a decane solution of asolectin. A very short light flash inducing a single turnover of the chromatophore photosynthetic redox system was found to induce the formation of an electrical potential difference amounting to 60 mV, directed across the film as measured with an orthodox electrometer technique. The main phase of the photoelectric response had a tau value of less than 200 ns. Addition of menadione and some other redox mediators increases the main phase amplitude and induces a slower phase (tau = 200 microseconds). In Ch. minutissimum chromatophores that retained their endogenous cytochrome c pool, one more electrogenic phase was revealed (tau = 20 microseconds). Redox titrations of the electric response and bacteriochlorophyll absorption at 430 nm as well as measurements of the kinetics of cytochrome c oxidation have indicated that the fastest electrogenic phase is due to electron transfer from bacteriochlorophyll to Fe-ubiquinone, the 20-microseconds phase to cytochrome c2+ - bacteriochlorophyll+ oxidoreduction, and the 200-microseconds phase to Fe-ubiquinone- oxidation by a secondary quinone. In the decay of the photoelectric response, a 30-ms phase was identified which was explained by a reverse electron transfer from reduced Fe-ubiquinone to oxidated bacteriochlorophyll. The difference in the fast kinetics of photoelectric generation by the bacteriochlorophyll system from those by bacterial and animal rhodopsins has been discussed.

Ascorbic Acid↗
PubMed1981

[Role of cofactors in membrane potential generation by Rhodospirillum rubrum chromatophores incorporated in a teflon filter].

The chromatophores of the bacterium Rhodospirillum rubrum were incorporated into a Teflon filter impregnated with a decane solution of phospholipids and the light-induced electric potential difference (delta psi) between the aqueous phases separated by the filter was measured. The generation of delta psi in such a system at continuous light requires the presence of cofactors, i. e. artificial electron donors and acceptors. These cofactors provide for a steady-state flow of e by regenerating the reduced form of the photo-oxidized reaction center bacteriochlorophyll and by reoxidizing the photo-reduced quinone acceptor of the reaction center. The most efficient donors are the reduced forms of nitrogen-containing redox mediators, e. g. TMPD, DAD, PMS, DCPIP and methylene blue, while p-benzoquinones with E07' approximately greater than 150 mV are practically inactive. The oxidized forms of nitrogen-containing mediators and a wide variety of p-quinones with E07' down to -220 mV can be used as electron acceptors. Using inhibitor analysis and compounds with different E0' it is shown that the cofactors donate electrons immediately to the reaction center bacteriochlorophyll and accept them from a low potential deprotonated form of the primary acceptor QI, substituting the secondary acceptor QII. The inability of hydrophilic sulfonate-substituted quinones to act as acceptors suggests that QI cannot be localized on the outer surface of the chromatophores.

Bacterial Chromatophores↗
PubMed1978

[Characteristics of the cellular RNA in viral leukemia].

A description is given of the differences in the fractional content of normal cell nuclear RNA and in Rauscher leukemia, which are manifested in the appearance of an accessory fraction 35 S RNA in leukemia-changed cells. The results of examining poly(A)-RNA amounts in normal splenic cells cytoplasm and nuclei, and in Rauscher leukemia are reported. The differences in the fractional content of poly(A)-RNA of normal leukemia changed cells are described.

Animals↗