Аңдатпа
Searching for toxin-producing cyanobacteria from Turgen gorge (Kazakhstan), Karlovy Vary (Czech Republic) and Shar-Nuur Lake, Bayan Ulgii region (Mongolia) springs, we have isolated seven algologically and five bacteriologically pure cultures of cyanobacteria. Among these strains, the highest toxicity (according to the Daphnia magna test) was exerted by the Desertifilum sp. and Nostoc sp. strains: the complete destruction of Daphnia was observed after 48 h. These strains also demonstrated the highest inhibitory effect on the proliferation of cancer HeLa cells. The Anabaena sp. 35 and Nostoc sp. 4 cyanobacteria were also classified as very toxic. The cyanobacteria model strains, Synechocystis PCC 6803 and Synechococcus elongatus PCC 7942, as well as Synechococcus sp. 55 isolated in this work, were rated as low toxic. The mass spectrometry analysis permitted to assign those strong cyanobacterial toxins to a type of cyclic depsipeptides. In extracts of Desertifilum sp., two cyclic depsipeptide, micropeptin T and oscillapeptin, were identified. In the extract of Nostoc sp., cryptophycin was detected together with a small amount of a cyclic depsipeptide, micropeptin SD.