Samoilenko V. Investigation of structural and functional organization of plasmid pSM1 and construction of the vector for the cyanobacterium Plectonema boryanum

The results of investigation of structural and functional organization of the endogenous plasmid pSM1 and the availability of bacterium Plectonema boryanum CALU 465 for construction of a vector-cell system are presented. The findings have allowed to designe new, more effective and functioning vector system. A physical map of pSM1 has been built as a result of restriction analysis. Analysis of nucleotide plasmid sequence have allowed to establish its replication mechanism and also the localization and size of a rep gene and ori. The cells of P.boryanum differed by sensitivity against ampicilin, tetraciclin, choramphenicol, streptomicin and canamicin. It has been shown that the nonspecific nuclease activity was presented on the cell's surface of cyanobacterium P.boryanum. Therefore the method of conjugative transfer has proved is most suitable for introduction of the vector into the cells of P.boryanum. The optimum condition of this method was determined. The plasmid vectors of pSTS-series have been constructed and introduced in P.boryanum cells for determination of theirs vector properties. It has been shown that effective shuttle-vector pSTS4 has to contain full-length cyanobacterial plasmid pSM1. pSTS4 replicates effective in P.boryanum and E.coli cells. The findings have allowed to approve that pSTS4 is the real shuttle-vector.