Chemical and Molecular Evidences for the Poisoning of a Duck by Anatoxin-a, Nodularin and Cryptophycin at the Coast of Lake Shoormast (Mazandaran Province, Iran)

Abstract

The toxic cyanobacteria in aquatic ecosystems are a big concern especially in warm summer months. Animals are incapable of avoiding toxic blooms near shore and might get poisoned. In this study, the aim was to find a cause of death of a domestic duck found near the coastal area of the Shoormast Lake, Iran. Cyanotoxin poisoning was suspected as the cause of fatalities, as a result, the water samples were collected and examined with phenotypic and genotypic analyses in order to find if the duck is poisoned by the toxic cyanobacteria. Different molecular and chemical methods such as phylogenetic analysis based on 16S rRNA gene sequence, polymerase chain reaction, disc diffusion bioassays and liquid chromatography-mass spectrometry were used. Based on the results, three different cyanobacteria strains were found in duck's stomach and three diverse groups of potentially bioactive compounds (anatoxin-a, nodularin and cryptophycin) might account for the death of this animal. The cyanobacteria strains were identified and registered under DDBJ as Anabaena sp. BN KY303913, Nodularia sp. BN KY303914 and Nostoc sp. BN KY303912. This case is the first documented incident of toxicity from fresh water cyanobacteria related intoxication in Iran.