Dolichospermum and Aphanizomenon as neurotoxins producers in some Russian freshwaters.

Last decades, cyanobacterial blooms have been commonly reported in Russia. Among the boom-forming species, potential toxin producers have been identified. The aim of this paper was to study the presence of neurotoxic compounds - saxitoxins and anatoxin-a - in water bodies from different regions of Russia. We also made attempts to identify the neurotoxin-producing genera. The good convergence of the results obtained by light microscopy, PCR and LC-MS/MS analyses indicated the presence of active neurotoxin producing species in all investigated water bodies. Saxitoxin was detected in phytoplankton from 4 water bodies in Central European Russia and West Siberia, including lake and reservoirs used as a source for potable water. The water bodies differed with the respect of saxitoxin producers which belonged to Aphanizomenon and/or Dolichospermum genera. For the first time, we obtained quantitative data on the intracellular saxitoxin concentration in Russian freshwaters using LC-MS/MS. Anatoxin-a was detected only in lakes of Northwestern Russia. In the eutrophic shallow Lower Suzdal Lake, Aphanizomenon was the stated anatoxin-a-producing genus. In the large shallow artificial hypertrophic Sestroretskij Razliv Lake, it was very likely that both dominant species - Aphanizomenon flos-aquae and Dolichospermum planctonicum - were anatoxin-a producers.