Cyanobacteria harmful algal blooms (cHABs) are associated with a wide range of adverse health effects that stem mostly from the presence of cyanotoxins. To help protect against these impacts, several health advisory levels have been set for some toxins. In particular, one of the more common toxins, microcystin-LR, has several advisory levels set for drinking water and recreational use. However,...

Cyanobacteria produce a wide range of potent toxins, including hepatotoxic microcystins. HPLC methods for microcystin analysis and purification almost invariably include acetonitrile in the elution gradient mobile phase. The recent, acute, global acetonitrile shortage requires that adequate methods are available for microcystin analysis and purification without the need for acetonitrile. Here w...

A previously undescribed cyclic heptapeptide hepatotoxin was isolated from a cyanobacteria waterbloom collected in Pakowki Lake, Alberta, Canada (49820 0N and 110855 0W). The compound was characterized by amino acid analysis, ESIMS/CID/MS, H and C NMR, and UV spectroscopy. Structure of the new microcystin was assigned as [d-Leu]microcystin-LR (1). The amino acid composition is the same as micro...

Microcystin-FR a cyclic heptapeptide was isolated from Nostoc spongiaeforme and purified by thin layer chromatography, MALDI TOFF Ms and HPLC methods. The Swiss albino mice dosed with the sub lethal concentration of 0.8μg/kg body weight of microcystin-FR were subjected to a battery of behavioural depression models such as tail suspension test (TST), force swim test (FST) and elevated plus maze ...

Blooms of microcystin-producing cyanobacteria are a problem worldwide. Microcystin is a liver hepatotoxin commonly found in bodies of water and is produced mainly by the genus Microcystis. The aim of the present study was to develop and assess a competitive PCR method for the quantification of toxic and non-toxic Microcystis cells using the cpcBA and mcyB genes, which are respectively involved ...

In early autumn 2011, three dogs died after they had been exposed to a Microcystis aeruginosa bloom on Lake Amstelmeer, The Netherlands. The cyanobacterial scum from the lake contained up to 5.27 × 103 μg g(-1) dry-weight microcystin, the vomit of one of the dogs contained on average 94 µg microcystin g(-1) dry-weight. In both cases, microcystin-LR was the most abundant variant. This is the fir...

Microcystins are cyanobacterial toxins that represent a serious threat to drinking water and recreational lakes worldwide. Here, we show that microcystin fulfils an important function within cells of its natural producer Microcystis. The microcystin deficient mutant ΔmcyB showed significant changes in the accumulation of proteins, including several enzymes of the Calvin cycle, phycobiliproteins...

Lake Erie beaches exhibit impaired water quality due to fecal contamination and cyanobacterial blooms, though few studies address potential relationships between these two public health hazards. Using quantitative polymerase chain reaction (qPCR), Microcystis aeruginosa was monitored in conjunction with a human-associated fecal marker (Bacteroides fragilis group; g-Bfra), microcystin, and water...

Cyanobacterial mass occurrences in freshwater lakes are generally formed by Anabaena, Microcystis, and Planktothrix, which may produce cyclic heptapeptide hepatotoxins, microcystins. Thus far, identification of the most potent microcystin producer in a lake has not been possible due to a lack of quantitative methods. The aim of this study was to identify the microcystin-producing genera and to ...

Cell-free extracts of Xenopus eggs support nuclear assembly and DNA replication in vitro. Extracts supplemented with the protein phosphatase inhibitor microcystin-LR displayed various inhibitory effects at different concentrations of the toxin. In the presence of cycloheximide, additions of microcystin did not induce histone H1-kinase activity. Nevertheless, increasing concentrations of microcy...