CHARACTERIZATION OF CYANOBACTERIA BY SDS-PAGE OF WHOLE-CELL PROTEINS AND PCR RFLP OF THE 16S RIBOSOMAL-RNA GENE/

Planktonic, filamentous cyanobacterial strains from different genera, both toxic and nontoxic strains, were characterized by SDS-PAGE of who le-cell proteins and PCR/RFLP of the 16S rRNA gene. Total protein pat tern analysis revealed the mutual relationships at the genus level. Re striction fragment length polymorphism (RFLP) of the 16S rRNA gene wit h reference strains proved to be a good method for the cyanobacterial taxonomy. The nonheterocystous strains outgrouped from the nitrogen-fi xing ones. With both methods, Aphanizomenon clustered with Anabaena, a nd Nodularia with Nostoc. In the RFLP study of Anabaena, the neurotoxi c strains were identical, but the hepatotoxic ones formed a heterogene ous group. Genetic distances found in the RFLP study were short, confi rming that close genotypic relationships underlie considerable diversi ty among cyanobacterial genera.