[Molecular cloning and functional analysis of DNA regions of plasmid RP4 determining the incompatibility properties].

Sau3A-generated DNA fragments determining incompatibility functions of the plasmid RP4 were cloned on the vectors pTK16 and pBR322. Inc+ recombinant plasmids were divided into two types: 1) expressing incompatibility only towards the homologous RP4 replicon, 2) expressing incompatibility - both towards the homologous RP4 replicon and towards the heterologous replicons of plasmids R906 and R751. For one member of the first type plasmids it was shown that the cloned Inc+-specific insertion derived from the region of location of the EcoRI restriction site.

[Properties of potential vectors--derivatives of the broad-host--range plasmid RP4].

Nonconjugative deletion and recombinant derivatives of the RP4 plasmid are constructed. The plasmids can be used as vectors because they have relatively small molecular weights, unique cleavage sites for enzymes EcoRI, XhoI, BamHI, PstI, KpnI, BglII, SalGI and HindIII (the plasmids pRP401 and pRP417 having six of these sites), and easily tested phenotypes (Tcr, Apr and Gal+). In addition, all of them retain the broad host range property.

[Molecular genetic studies of the DNA promotor regions in Bacillus thuringiensis subsp. galleriae 69-6. II. Increased level of gene expression resulting from IS1 element integration].

The 1.45 kb promoter containing HindIII fragment of Bacillus thuringiensis DNA promotes the expression of the tet gene of recombinant pPBT9 plasmid in Escherichia coli cells. Spontaneous mutants of this plasmid were isolated and analysed.

[Bacteriocinogenic plasmids of Bacillus thuringiensis].

When strains of Bacillus thuringiensis v. morrisoni or v. darmstadiensis were plated on solid medium, the appearance of oligosporogenic (Ospo) mutants and bacteriocin non-producing clones (Thc-) was observed.

[Homology of plasmids with a wide range of hosts].

According to blotting hybridization and heteroduplex analysis, plasmids R751, R906 and RP4 of Inc Pi group have continuous regions of homology. These homologous regions were mapped on the R751 and RP4-derived pRP401 deletion mutant DNAs. The plasmid pRP401 (m.