cause acute hepatotoxicity and chronic liver tumor promotion. This study presents
the results of HPLC DAD analyses and their LC-MS confirmation of samples from five
Bulgarian water bodies (reservoirs Stoudena, Pchelina, Bistritsa and lakes Dourankoulak,
Vaya). The total concentration of microcystins in water samples ranged from 0.1
to 26.5 μg/l. The amount of microcystins
in the biomasses ranged from 11.4 to 49.6 μg/g (d.w.). The high percent of positive
samples in which the most toxic microcystin-LR is recorded, can serve as a strong
alarm for the necessity of a serious study and relevant discussion of the problem
with responsible authorities at national level.
Cylindrospermopsin (CYN) is an alkaloid that causes hepatotoxicity, neurotoxicity and general cytotoxicity in vertebrates. It is currently gaining widespread attention after its reported appearance in water bodies around the world. A. ovalisporum is capable of CYN-production and can form toxic blooms when favorable environmental conditions are available. We have developed for the first time a two-step qPCR assay using Taqman probes to detect and quantify potential CYN-producing A. ovalisporum in water samples. The assay was sensitive enough to discriminate between CYN-producing and non-CYN-producing A. ovalisporum in a mixed background, and discriminate between A. ovalisporum and other nostocales as C. raciborskii and A. bergii. The detection limit of the assay falls in the log linear range of 102 and 105 gene copies per reaction and is thus within the sensitivity range of previously published assays for the detection of other toxic cyanobacteria species. Our assay allows for the first time to quickly assess water quality for the presence of potentially CYN-producing A. ovalisporum and can be easily used for the purposes of monitoring water bodies.