[Site-specific restrictases from Bacillus thuringiensis var. Kumantoensis]. / Saitspetsificheskie restriktazy iz shtamma Bacillus thuringiensis var.Kumantoensis.

The efficiency of bacteriophages CP-54 and CP-55 plating on Bacillus thuringiensis var. kumantoensis H18 (Kum) is decreased about 10-fold as compared with the efficiency of plating on Bacillus thuringiensis var. galleriae H5 (Gal). Bacteriophages having propagated for one cycle in Kum cells might be further grown in this strain without growth restriction. Two site-specific restriction enzymes isolated from Bacillus thuringiensis var. kumantoensis were designated BtkI and BtkII. The endonuclease BtkI recognises the same nucleotide sequence CGCG in DNA as recognised by the restriction endonuclease FnuDII; BtkII recognises the same nucleotide sequence GATC as the endonuclease Sau3A.

[Variability of Bacillus thuringiensis bacteriophages with C2-morphology]. / Variabel'nost' fagov Bacillus thuringiensis C2-morfologii.

Biological as well as physicochemical properties of Bacillus thuringiensis bacteriophages "17" and "7/13" having C2-morphology and isolated from factory phagolysates were studied. The bacteriophages are identical in the lytic spectrum++, morphology, size, GC-content, have the same buoyant density. The physical map for restriction endonucleases EcoRI, HindIII, SalGI and MvaI has been constructed of the bacteriophages DNA. Heteroduplex analysis has revealed the nonhomologous region of the deletion-insertion type as a 0.8 Md loop. The bacteriophages "17" and "7/13" are concluded to be closely related but not identical.

[Extracellular serine proteinase of Bacillus thuringiensis]. / Vnekletochnaia serinovaia proteinaza Bacillus thuringiensis.

Pure extracellular serine proteinase has been isolated from a broth filtrate of Bacillus thuringiensis, strain 69-6R by fractionation with ammonium sulfate and affinity chromatography on Sepharose 4B derivatives containing p-(omega-aminomethyl)-phenylboronic acid and cyclopeptide bacillichin as ligands. The enzyme is completely inactivated by phenylmethylsolfonyl fluoride, a specific reagent for serine proteinases, has the molecular weight of 29 000 and pI of 8.4, reveals maximal activity and stability at pH 8.5 and is inactivated at pH values below 4 and above 10 and at temperatures above 60 degrees. The enzyme hydrolyzed azokasein, bovine serum albumin and synthetic chromogenic peptide substrates, e.g. benzyloxycarbonyl-L-alanyl-L-alanyl-L-leucyl p-nitroanilide and possesses the esterolytic activity. In terms of its physico-chemical characteristics, interaction with specific inhibitors and substrates, extracellular serine proteinase from Bacillus thuringiensis can be related to subtilisins. However, its amino acid composition-Lys16, His4, Arg8, Asx28, Thr16, Ser18, Glx29, Pro12, Gly32, Ala31, Val19, Met5, Ile12, Leu18, Tyr11, Phe10, Trp4 appears to be an intermediate between that of subtilisins and intracellular serine proteinases of Bacilli.

[Electron microscopic study of the interaction between phages and Bacillus thuringiensis cells]. / Elektronno-mikroskopicheskoe i zuchenie vzaimodeistviia fagov s kletkami Bacillus thuringiensis.

The interaction of phages belonging to different morphological groups with the cells of Bacillus thuringiensis var. galleriae R and S variants was studied. No adsorption of phages Tg11 and Tg18 on the cells of R variant was found upon infection in a liquid medium. What is characteristic of phage Tg11 is that it is predominantly adsorbed at the poles of S variant cells. Phage Tg18 particles are uniformly distributed along the perimeter of S variant cells. Phage Tg13 is adsorbed on the both variant cells. Phage aggregates with the elements of cell walls having a tetrahonal assembly of the subunits can be revealed in phage Tg13 lysates. The size of the subunits is 7 nm and the distance between their centers is 11 nm. A structured element, apparently the T-layer, is involved in the adsorption of phage Tg13 on the cells.

[Bacteriocin-like factor in Bacillus thuringiensis]. / Bakteriotsino-podobnyi faktor Bacillus thuringiensis.

The paper describes Bacillus thuringiensis var. galleriae strains possessing a bacteriocin-like factor (factor K) which inhibits the cultures of a number of serotypes of Bac. thuringiensis. The K+ cultures exhibit no antibacterial effect on other gram-positive and gram-negative microorganisms. The maximal level of factor K is found by the 8--9th hour of cultivation. No correlation has been established between the strucutred elements in the preparations of K+ cultures and the antibacterial activity. Apparently, factor K can be transferred to other strains.

[Comparative characteristics of spore-forming and asporogenic strains of Bacillus thuringiensis]. / Sravnitel'naia kharakteristika sporoobrazuiushchikh i asporogennykh shtammov Bacillus thuringiensis.

Comparative characteristics of sporogenous and asporogenous Bacillus thuringiensis strains is carried out. Asporogenous strains are found to differ from wild type strains in a number of criteria, including colony morphology, character of growth on rich and poor media and UV-sensitivity. Sporogenous strains form R colonies, they are more stable and more rare produce variants forming S colonies. S colonies are typical for asporogenous mutants, and under the cultivation in unfavourable conditions (elevated temperature, a shift of pH, a change of an incubation regime) asporogenous strains dissociate with a high frequency into R form. Initial strains, which are multiple auxotrophs, under certain conditions can form "prototrophic" revertants which are unstable when incubated on rich media. Suppressor mutation is supposed to be a possible mechanism of the origination of "prototrophs".

[Electron microscopic study of the cells of variants of Bacillus thuringiensis var. galleriae forming colonies with altered morphology]. / Elektronno-mikroskopicheskoe izuchenie kletok u variantov Bacillus thuringiensis var. galleriae obrazuiushchikh kolonii s izmenennoi morfologiei.

Colonial-morphological variants of Bacillus thuringiensis var. Galleriae were studied by electron microscopy. The S variant was found to be asporogenous, whereas the R variant produced mature spores. Morphological modifications in the cell were followed in the course of sporulation. Spores were shown to have thin filamentous and tubular protrusions which had not been so far described in crystalliferous bacteria. Preparations from colonies of the R variant contained peculiar structures which resembled phage tails. A possible function of these structures is discussed.

Induction of mutants with altered DNA composition: effect of ultraviolet on Bacterium paracoli 5099.

The culture of Bacterium paracoli 5099 represents a favorable system for induction of mutants with altered DNA base composition. The frequency of induction of these mutants by ultraviolet radiation is strongly dose-dependent, and has a peak at the ultraviolet exposure equal to 860 ergs. On both sides of this maximum the rate of appearance of mutants decreases, and with the exposures less than 350 and more than 1900 ergs per square millimeter, mutants with altered DNA base composition do not appear at all.