[pSTS4--a new shuttle vector for cyanobacterium Plectonema boryanum CALU 465].

Three vector constructions--pSTS2, pSTS3 and pSTS4 have been obtained on the basis of the standard vector for Escherichia coli pBR 322, cyanobacterial plasmid pSM1 and its separate fragments. The structure of pSTS4, carrying the full-size plasmid pSM1 (cloned by the restriction site Hpa II), replicated both in the cells of E. coli and in the cells-transconjugants of the trichomal cyanobacterium Plectonema boryanum.

[The nucleotide sequence of the rep gene of cyanobacterial plasmid pSM1].

The nucleotide sequence was established for the rep gene of plasmid pSM1 isolated from cyanobacterium Plectonema boryanum CALU 465. Both nucleotide sequence and the encoded amino acid sequences showed 98% homology to the corresponding sequences of small plasmids pPF1, pGL3, pPBS1, pBLX, and pPB1. An active center was identified in the replicative protein sequences.

[Isolation and purification of nonspecific nuclease of cyanobacterium Plectonema boryanum CALU 465].

Nonspecific nuclease has been isolated from the cells of cyanobacterium Plectonema boryanum and purified to homogenic state. It has been established that the method of centrifugation of cell-free culture extract in the sucrose density gradient is efficient for the separation of pigment proteins and enzyme concentration. Under the successive use of two ion-exchangers the nuclease activity was determined in the concentration range of NaCl 0.

[Localization of DNAase activity in cyanobacterium Plectonema boryanum CALU 465].

It was shown in experiments carried out on cyanobacterium P. boryanum, that when cells are incubated in a buffer with low concentrations of nonion detergent (0.1%, Triton X-100) one can observe the DNAse activity release into the medium.

[Construction of vector plasmids for the Plectonema boryanum cyanobacterium and creation, on such basis, of the vector-host system].

The plasmid composition of the Plectonema boryanum Gom. Cyanobacterium, strain CALU 465, was analyzed. A small pSM1 plasmid, size 1.