[The colony architectonics in Bacillus subtilis 2335]. / Osobennosti stroeniia kolonii Bacillus subtilis 2335.

Colonies grown from vegetative B. subtilis 2335 cells had a standard structure, with bacillar cells occupying the whole colony volume. At the same time, the colonies of this bacterium grown from germinated spores had an abnormal structure characterized by the location of cells in a surface layer 100-200 microns thick at the colony boundary with the air. The glycocalyx of the colonies grown from spores was characterized by a wetting angle theta e of 120 degrees-160 degrees, whereas that of the colonies grown from vegetative cells had an angle theta e as low as 5 degrees-30 degrees. It is suggested that spores and vegetative cells follow different strategies of substrate colonization and that the architectonics of bacterial colonies is determined by the physicochemical properties of the glycocalyx.

[Stability of recombinant plasmids in transgenic microorganism cells under various environmental conditions]. / Stabil'nost' podderzhaniia rekombinantnykh plazmid v kletkakh transgennykh mikroorganizmov pri raznykh usloviiakh sushchestvovaniia.

The copy number of R plasmids weakly depends on the selective pressure of the respective antibiotic but does depend on the physiology of the host species and the type of plasmids and cloned genes, whose expression leads to a further load on the biosynthetic apparatus of cells. The last factor is critical in the maintenance of recombinant plasmids in transgenic microorganisms.

[Factor of salinity and adaptive capacity of recombinant strains of Escherichia coli and Bacillus subtilis]. / Faktor solenosti i adaptivnye vozmozhnosti rekombinantnykh mikroorganizmov Escherichia coli i Bacillus subtilis.

Effect of different concentrations of salts on natural and recombinant strains of Bacillus subtilis and Escherichia coli was studied. The recombinant strain of B. subtilis was found to be more osmotolerant than the wild-type strain of this bacterium, whereas the opposite situation was observed for the recombinant and wild-type strains of E. coli. Some salts exerted a bacteriostatic effect on E. coli and B. subtilis. The adaptive capacity of recombinant strains depended on the number of plasmid copies in the cells. The introduction of recombinant bacteria into model ecosystems resulted in the generation of their variants with increased osmotolerance.

[The study of heterogeneity of plasmid-bearing and plasmid-f ree populations of Bacillus subtilis under different environmental conditions]. / Izuchenie geterogennosti v populiatsiiakh plazmidosoderzhashchego i besplazmidnogo shtammov Bacillus subtilis v raznykh usloviiakh su shchestvovaniia.

The population heterogeneity of recombinant and plasmid-free Bacillus subtilis strains introduced into aquatic microcosms was studied. After introduction, the population of the plasmid-free strain B. subtilis 2335 in microcosms has long been represented by both vegetative cells and spores, whereas, already ten days after introduction, the population of the recombinant strain B. subtilis 2335/105 (Km[symbol: see text]nf+) was represented only by spores. The number of plasmid copies in the spore isolates of the recombinant strain was the same as before introduction, but the plasmid abundance in the vegetative isolates of this strain decreased. The isolates of B. subtilis 2335/105 obtained from microcosms and the variants of this strain obtained by ten successive subcultures on M9 and 0.1 x M9 media with and without kanamycin (Km) differed in the number of plasmid copies, Km resistance, and maximum biomass yield during batch cultivation. Irrespective of the presence of Km, more than 50% of the variants subcultured on M9 medium showed reduced plasmid abundance. At the same time, about 70% of the variants subcultured on 0.1 x M9 medium with Km and 90% of the variants subcultured on the same medium without Km retained the initial number of plasmid copies. The variants subcultured on media with Km retained the initial biomass level. In more than 70% of the variants isolated from media without Km, the biomass yield increased.

[The comparative growth characteristics of variants of a recombinant Escherichia coli strain and of the representatives of aboriginal microflora in aqueous microecosystems under selective and nonselective conditions]. / Sravnitel'naia kharakteristika rosta variantov rekombinantnogo shtamma Escherichia coli i prestavitelei aborigennoi mikroflory vodnykh mikroékosistem v selektivnykh i neselektivnykh usloviiakh.

We have studied the kinetic characteristics of several isolates of Escherichia coli Z905 recombinant strain after introduction of the strain into model aquatic ecosystems. Most E. coli Z905 isolates grown as batch cultures under selective conditions (0.5 microgram/ml ampicillin) showed better kinetic characteristics of growth than did related species of native microflora, which originally populated laboratory microcosms.