[Protoplasts of lincomycin producer Streptomyces roseolus in genetic manipulations]. / Protoplasty Streptomyces roseolus produtsenta linkomitsina v geneticheskikh manipuliatsiiakh.

Protoplasts of commercial strain No. 1 of Streptomyces roseolus producing lincomycin were prepared. Conditions for protoplast storage and regeneration were defined. The protoplasts of strain No. 1 mutants marked by the rifampicin and thiostrepton resistance and the ability to synthesize melanin pigments were fused. Genetic analysis of the recombinants was performed. Systems for transformation of S. roseolus protoplasts by plasmid DNAs were developed. Efficiency of transformation by pIJ702, pIJ61, pVG101 and pBG3 and stability of the transformants were shown.

[Preparation and characteristics of protoplasts of Streptomyces kanamyceticus]. / Poluchenie i kharakteristika protoplastov shtamma Streptomyces kanamyceticus.

To prepare actively regenerating protoplasts of S. kanamyceticus, the influence of the conditions of the mycelium cultivation, the culture age, lytic conditions, composition of the regeneration medium, the procedure of the culture inoculation to the regeneration medium and other parameters were studied. The study resulted in development of optimal conditions for preparation of S. kanamyceticus protoplasts in a number of 1.10(9) protoplasts per ml. The cultivation on the ST medium with 10 to 15% sucrose and addition of glycine up to 1% for 30 hours (the stationary growth phase) followed by treatment of the culture with lysozyme in an amount of 2 mg/ml for 1 hour at 32 degrees C provided preparation of up to 100% of actively regenerating protoplasts free of mycelium fragments. The size of the protoplasts increased up to 1.5 micron against the usually observed size of 0.7 to 1.0 micron with using modified lyzing buffer with 20% of sucrose according to the method recommended for S. erythreus. However, 50 to 70% of the protoplasts had point of linear regions in the cell walls, which suggested that spheroplasts were mainly forming and the phenomenon was associated with the characteristic properties of the strain cell wall structure.

[Comparative restriction analysis of chromosomal DNA of strains of Photobacterium leiognathi]. / Sravnitel'nyi restriktsionnyi analiz khromosomnoi DNK shtammov Photobacterium leiognathi.

Chromosomal DNA in 5 hereditary variants occurring in Photobacterium leiognathi population was subjected to restriction analysis. The variants differed in the levels and regulation of luminescence and colony morphology. Agarose electrophoresis of DNA fragments isolated after exposure to Hind II, Bam HI, Bgl I and Pst I restriction endonucleases revealed respectively 38, 28, 35 and 29 fragments equally distributed by their molecular weights. Electrophoregrams of the 5 strains were absolutely identical. After exposure of DNA of all the strains to PVu II, Xho II, Sal GI and Eco RI restriction endonucleases there were detected no fragments. The pleoiotropic genetic variation in these strains was not associated with large deletions or amplification of chromosomal DNA regions.

[Design of hybrid plasmids based on the actinomycete plasmid pSB24.1 and plasmid prBR325 and a study of their stability in the Streptomyces-E. coli system]. / Konstruirovanie gibridnykh plazmid na osnove aktinomitsetnoi plazmidy pSB 24,1, plazmidy pBR325 i izuchenie ikh stabil'nosti v sisteme Streptomyces-E. coli.

Actinomycete plasmid pSB24.1 was cloned on vector of the E. coli pBR325 system. The following bireplicon plasmids were obtained: pSU501 and pSU502 (by XhoI site of pSB24.1 and SalGI site of pBR325), pSU503 (by Bg1II (c) site of pSB24.1 and BamHI site of pBR325) and pSU504 (by Bg1II(b) site of pSB24.1 and BamHI site of pBR325). In the cells of E. coli C600 plasmids pSU501-504 determined phenotype AprCmrTcs and were stable. In the cells of Str. lividans the initial structure pSU501 selected by Ltz+ phenotype was maintained at a frequency of 12.5 per cent. Analysis of the deletion variants of pSU501 isolated from Str. lividans showed that the deletions were induced by both the pBR325 region and the pSB24.1 DNA fragment near XhoI site. The region from SacII(a) site to Bg1II(b) site clockwise in the map of plasmid pSB24.1 was not significant for its replication and maintenance in Str. lividans. There were detected unique sites of pSB24.1 and its derivatives useful for cloning. Possible shortening of plasmid pSB24.1 by 567 kb (the length between the terminator of the open frame reading translation and XhoI site) was revealed.

[Isolation and characteristics of plasmid DNA from Lactobacilli]. / Vydelenie i nekotorye kharakteristiki plazmidnoi DNK iz laktobatsill.

It was shown on a model of 2 collection strains of lactobacilli that their cultivation on a synthetic multicomponent medium with addition of threonine and subsequent exposure of the cells to lysozyme at 0 degrees C and to alkaline solution of sodium dodecylsulfate at 60 degrees C provided highly efficient detection of plasmid DNA in these organisms. Circular molecules of the plasmid DNA of the 7-kv length, their dimer forms and linear molecules were detected in both of the strains.

[Taxonomic analysis of Pegosomum asperum and P. saginatum (Trematoda: Echinostomatidae)]. / Taksonomicheskii analiz Pegosomum asperum i P. saginatum (Trematoda: Echinostomatidae).

Morphology, ecology and chromosomes of P. asperum and P. saginatum were investigated. The both species have a diploid set consisting-of 20 chromosomes with similar morphology and size of bivalents. Their karyotypes are supposed to be identical. According to their morphology and ecology the both species are clearly differentiated. A conclusion is drawn on the distinct status of these trematodes having originated as a result of simpatric speciation.