RESUMO
Three methods of plasmids isolation from the cells of cyanobacteria: Plectonema boryanum 465, P. nostocorum 636, P. nostocorum 638, P. edaphicum 262, Plectonema sp. 456, Phormidium uncinatum 528, Anabaena variabilis 458 and Synechococcus cedrorum 750 have been approved. The method of plasmids isolation by 1 M NaCl salting out was used for plasmid screening. All the strains studied contained large, above 55 KB plasmids, small plasmids (1.5 KB) were found in the cells of P. boryanum 465 and P. nostocorum 636. After the restriction analysis a small plasmid of P. boryanum 465 was chosen to be used in the experiments on the vector construction. The above plasmid was called pSM1 was cloned into the vector pBluescri ptIISK(+) on the unique ClaI site. The obtained construction pBSMI may be used as the basic one for creation of cyanobacterial vectors.