[Effect of Yersinia pseudotuberculosis pVM82 on the activity of components of complement and phagocytosis by human blood neutrophils]. / Vliianie plazmidy pVM86 Yersinia pseudotuberculosis na aktivnost' komponentov komplementa i fagotsitoz neitrofilami krovi cheloveka.

Three isogenic Y. pseudotuberculosis strains were studied. One of them contained pVM82 plasmid which was found in foci of pseudotuberculosis outbreaks and increased Yersinia resistance to blood serum. Cells with pVM82 plasmid did not inhibit the activation of complement components C1, C2, C3, C4, and C5 in human serum and increased the consumption of these complement components in comparison with control strains. Y. pseudotuberculosis cells with pVM82 were better resistant to human neutrophil phagocytosis than bacterial cells without this plasmid. For the strain with pVM82 plasmid, a lower level of phagocytosis within the first 30 min of Y. pseudotuberculosis incubation with neutrophils and a reduced percentage of killed bacteria among all those phagocytosed over the entire period of incubation of bacteria with neutrophils were observed.

[Phenotypic features of a strain of Yersinia pseudotuberculosis with the pVM82 plasmid, detected at pseudotuberculosis outbreak foci]. / Fenotipicheskie osobennosti shtamma Yersinia pseudotuberculosis s plazdmidoi pVM82, obnaruzhivaemoi v ochagakh vspyshek psevdotuberkuleza.

The phenotypic properties conferred to Yersinia pseudotuberculosis cells by the genetical determinants of a 25Md fragment of the plasmid pVM82 coding for the modified cellular immune response in the infected organism. The fragment was shown to determine the conjugative properties of the plasmid, the resistance of bacterial cells to a number of hydrophobic agents and cellular ability to absorb the Congo red dye. The latter confirms the presence of additional structural components in the cell wall of the strain harbouring the plasmid pVM82. The increased resistance of the plasmid-containing strain to bactericidal effect of the blood plasma was demonstrated as compared with the resistance of the strains harbouring the p57 plasmid lacking the 25Md fragment or no plasmid at all.

[Expression of delta-endotoxin gene from Bacillus thuringiensis var. berliner 1715 in Escherichia coli and Bacillus megaterium cells]. / Proiavlenie gena delta-éndotoksina Bacillus thuringiensis var. berliner 1715 v kletkakh Escherichia coli i Bacillus megaterium.

Effects of the structure of plasmids carrying the cloned delta-endotoxin gene (tox) ot Bacillus thuringiensis and of the culture media on the expression of the gene have been studied. The DNA region located upstream from the crystal protein gene promoter inhibited the expression of the tox gene in Escherichia coli cells, but enhanced the expression in Bacillus megaterium cells grown in LB medium. The upstream DNA region did not affect the tox gene expression when Bacillus megaterium cells were grown in SSM medium.

[Expression of the phospholipase C gene of Pseudomonas aeruginosa in Escherichia coli and Pseudomonas]. / Ekspressiia gena fosfolipazy s Pseudomonas aeruginosa v kletkakh kishechnoi palochki i psevdomonad.

The plc gene for phospholipase of Pseudomonas aeruginosa, able to be transcribed only from its own promoter, has been introduced into Escherichia coli, Pseudomonas aeruginosa and Pseudomonas putida cells in the recombinant plasmid pPMS21 of a wide host range. The expression of plc gene in all recipient cells has been shown to be phosphate regulated. The fact emphasizes the identity of pho-regulation systems in Escherichia coli and Pseudomonas cells. The level of phospholipase activity is similar in Pseudomonas putida and Pseudomonas aeruginosa under the conditions of the gene derepression, while in Escherichia coli cells the level does not exceed 10% of activity registered in Pseudomonas cells.

[Mutation slowing down the degradation of the beta beta'-subunits of Escherichia coli RNA-polymerase]. / Mutatsiia, zamedliaiushchaia degradatsiiu beta beta'-sub"edinits RNK-polimerazy Escherichia coli.

The rpoC1 ts mutation affecting the RNA polymerase beta' subunit accelerates synthesis of RNA polymerase beta beta' subunits at 42 degrees C, while the surplus amount of subunits degrades in an hour's time. In a Ts strain with two RNA polymerase mutations, rpoC1 and rpoB251, we obtained a ts+ reversion designated opr24 which slows down degradation of surplus beta beta' subunits. The slowing down of degradation and the resulting accumulation of beta beta' subunits does not affect the kinetics of beta beta' subunit synthesis after the transfer to 42 degrees C. The effects of the opr24 are allele non-specific. The mutation also slows down degradation of beta' subunit and the amber fragment of beta subunit in the strain with subunit amber mutation rpoB22. Besides, the opr24 mutation reduces proteolysis of anomalous proteins containing canavanine. The opr24 mutation has been mapped between 17 and 21 minutes on the Escherichia coli map.

Decreased degradation of beta beta' RNA polymerase subunits and abnormal proteins in a mutant E. coli.

An opr24 mutation decreasing the degradation of RNA polymerase beta beta' subunits was found among the Ts+ revertants of Ts strain carrying an rpoC1 mutation which stimulates overproduction of these polypeptides. The opr24 mutation is allele-non-specific, for it decreases the degradation of the mutant beta and beta' subunits, the amber-fragment of the beta subunit and the non-mutant beta' subunit. Moreover, opr24 reduces the proteolysis of abnormal proteins containing canavanine. The opr24 mutation maps between 17 and 21 min on the E. coli genetic map. The results demonstrate that a slow proteolysis rate in the bacterial cell can suppress conditional lethal mutations. In addition, the slower degradation and the ensuing accumulation of beta beta' subunits does not effect the rate of the beta beta' subunit synthesis.

[Mutation affecting the rate of RNA-polymerase beta beta'-subunit synthesis in Escherichia coli]. / Issledovanie mutatsii, vliiaiushchei na skorost' sinteza beta beta'-sub"edinits RNK-polimerazy Escherichia coli.

As shown previously, rpoC1 temperature sensitive mutation affecting RNA polymerase beta' subunit, results in acceleration of beta beta' subunit synthesis at 42 degrees C. Also, it leads to the change in RNA polymerase sedimentation coefficient and to the reduction of RNA polymerase activity in vitro. According to the existing hypotheses, these properties of a mutant enzyme may be the cause of acceleration of synthesis of RNA polymerase in vitro. The opr1 mutation was found among Ts+ revertants of the Ts double mutant carrying rpoC1 and rif-r rpoB251 mutations. Reduction of the rate of beta beta' subunit synthesis caused by the opr1 mutation, is related to the structural changes of RNA polymerase itself. It has been shown, however, that the low activity in vitro and the altered sedimentation coefficient of the enzyme are not responsible for the accelerated synthesis of beta beta' subunits at 42 degrees C in the RpoC1 strains. Opr1 is a dominant mutation and it is located in the rpoBC region of the genetic map of Escherichia coli chromosome.