Such plasmids (not able to replicate in many hosts) may carry highly recombinogenic TEs (i.e. insertion sequences, transposons, or transposable modules), whose activity may lead to insertion of the TEs (or the whole plasmids) into the chromosome or natural plasmid of a new host. The transferred genes can be therefore maintained as a part of the host genome. This strongly suggests that NHR mobilizable plasmids may act as natural suicide vectors promoting the

dissemination of diverse genetic information in HGT over a much wider range than previously selleck thought. We acknowledge L. Drewniak, R. Matlakowska, A. Sklodowska (Laboratory of Environmental Pollution Analysis, University of Warsaw) for providing bacterial strains and G. Jagura-Burdzy, A. Bartosik (Institute of Biochemistry and Biophysics, Polish Academy of Sciences) for providing mini-derivative

of plasmid RA3 used for construction of vector pMAO1. This work was supported by the State Committee for Scientific Research, Poland (grant PBZ-MNiSW-04/I/2007). “
“The calY gene, encoding metalloprotease camelysin in the Bacillus thuringiensis acrystalliferous strain XBU001, was amplified and sequenced. The camelysin from the calY sequence was 199 amino acids in size (c. 22 000 Da). The temperature-sensitive plasmid pKESX was used to construct a metalloprotease 5-Fluoracil camelysin-deficient strain of B. thuringiensis. The calY gene was replaced by an erythromycin-resistant gene in KCTF. Sodium dodecyl sulfate

polyacrylamide gel electrophoresis and MS analysis showed that the metalloprotease InhA was not expressed after knocking out the gene calY. The temperature-sensitive plasmid pKPC was used to construct a metalloprotease camelysin complementation strain KCTFC. The InhA protein was found in KCTFC. Analysis of the expression of InhA in the wild-type strain KCTF12, camelysin-deficient and complementation strains indicated that inhA expression depended on camelysin. Although camelysin did not directly regulate the expression of the InhA through binding to the promoter of the inhA, the results suggest that camelysin can positively regulate the expression of the InhA protein. Bacillus thuringiensis has been widely used in the control of a variety of agricultural pests and vectors of human diseases (Liang et al, 2007). During spore formation, B. thuringiensis subspecies produce Metalloexopeptidase large amounts of various crystal proteins in the form of protoxins (Cry or Cyt) (Nisnevitch et al., 2006; Zhao et al., 2009). In addition to crystal proteins, B. thuringiensis produces several secreted proteins, such as phospholipases C, proteases, parasporin-1 and other components that might contribute to its pathogenicity (Salamitou et al., 2000; Katayama et al., 2007). Camelysin expressed during the exponential growth phase was first purified from Bacillus cereus. The mature camelysin is a protein of 170 amino acid residues with a molecular mass of 19.056 kDa and pI of 4.56.