The environmental occurrence and concentrations of cyanobacterial toxins (cyanotoxins) were investigated in the Czech Republic. Concentrations of microcystins (MCs), cylindrospermopsin (CYN) or saxitoxins (STXs) were determined immunochemically by ELISA assays in 30 water samples collected from the surface layers of 19 reservoirs during the summer season of 2010. MCs were detected in 18 reservoirs and 83 % of samples, with median and maximal concentration being 1.5 and 18.6 μg/L, respectively. The high frequency of MC occurrence coincided with prevalence of cyanobacterium Microcystis sp., which was detected in 87 % samples, followed by Dolichospermum (Anabaena) sp. observed in 33 % samples. CYN was detected by ELISA only in one sample at a concentration of 1.2 μg/L. STXs presence was indicated for the first time in Czech water reservoirs when the toxins were found at low concentrations (0.03-0.04 μg/L) in two samples (7 %) collected from two different reservoirs, where STXs co-occurred with MCs and eventually also with CYN. In both STX-positive samples, the phytoplankton community was dominated by Microcystis sp., but Dolichospermum sp. and/or Aphanizomenon sp. were also present as putative producers of STX and/or CYN. Cyanotoxins commonly occurred in Czech water reservoirs, and MCs frequently at concentrations possibly associated with human health risks. MCs were the most prevalent and abundant cyanotoxins, but also other cyanotoxins were detected, though sporadically. Further research and regulatory monitoring of cyanotoxins other than MCs is therefore required.

• MeSH
• Alkaloids MeSH
• Anabaena isolation & purification   MeSH
• Aphanizomenon isolation & purification   MeSH
• Bacterial Toxins analysis   MeSH
• Enzyme-Linked Immunosorbent Assay MeSH
• Phytoplankton isolation & purification   MeSH
• Microcystis isolation & purification   MeSH
• Water Microbiology * MeSH
• Microcystins analysis   MeSH
• Environmental Monitoring methods   statistics & numerical data   MeSH
• Marine Toxins analysis   MeSH
• Neurotoxins analysis   MeSH
• Saxitoxin analysis   MeSH
• Cyanobacteria isolation & purification   MeSH
• Fresh Water chemistry   microbiology   MeSH
• Cyanobacteria Toxins MeSH
• Uracil analogs & derivatives   analysis   MeSH
• Water Supply analysis   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Czech Republic MeSH
• Names of Substances
• Alkaloids MeSH
• Bacterial Toxins MeSH
• cylindrospermopsin MeSH Browser
• microcystin MeSH Browser
• Microcystins MeSH
• Marine Toxins MeSH
• Neurotoxins MeSH
• Saxitoxin MeSH
• Cyanobacteria Toxins MeSH
• Uracil MeSH

Toxicity and liver tumor promotion of cyanotoxins microcystins have been extensively studied. However, recent studies document that other metabolites present in the complex cyanobacterial water blooms may also have adverse health effects. In this study we used rat liver epithelial stem-like cells (WB-F344) to examine the effects of cyanobacterial extracts on two established markers of tumor promotion, inhibition of gap-junctional intercellular communication (GJIC) and activation of mitogen-activated protein kinases (MAPKs) - ERK1/2. Extracts of cyanobacteria (laboratory cultures of Microcystis aeruginosa and Aphanizomenon flos-aquae and water blooms dominated by these species) inhibited GJIC and activated MAPKs in a dose-dependent manner (effective concentrations ranging 0.5-5mgd.w./mL). Effects were independent of the microcystin content and the strongest responses were elicited by the extracts of Aphanizomenon sp. Neither pure microcystin-LR nor cylindrospermopsin inhibited GJIC or activated MAPKs. Modulations of GJIC and MAPKs appeared to be specific to cyanobacterial extracts since extracts from green alga Chlamydomonas reinhardtii, heterotrophic bacterium Klebsiella terrigena, and isolated bacterial lipopolysaccharides had no comparable effects. Our study provides the first evidence on the existence of unknown cyanobacterial toxic metabolites that affect in vitro biomarkers of tumor promotion, i.e. inhibition of GJIC and activation of MAPKs.

• MeSH
• Enzyme Activation drug effects   MeSH
• Alkaloids MeSH
• Aphanizomenon chemistry   isolation & purification   MeSH
• Bacterial Toxins MeSH
• Cell Line MeSH
• Time Factors MeSH
• Extracellular Signal-Regulated MAP Kinases metabolism   MeSH
• Phosphorylation drug effects   MeSH
• Carcinogens chemistry   toxicity   MeSH
• Complex Mixtures chemistry   toxicity   MeSH
• Rats MeSH
• Gap Junctions drug effects   MeSH
• Cell Communication drug effects   MeSH
• Microcystis chemistry   isolation & purification   MeSH
• Microcystins analysis   toxicity   MeSH
• Mitogen-Activated Protein Kinases metabolism   MeSH
• Cyanobacteria chemistry   isolation & purification   MeSH
• Fresh Water microbiology   MeSH
• Cyanobacteria Toxins MeSH
• Uracil analogs & derivatives   toxicity   MeSH
• Dose-Response Relationship, Drug MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Comparative Study MeSH
• Geographicals
• Czech Republic MeSH
• Names of Substances
• Alkaloids MeSH
• Bacterial Toxins MeSH
• cylindrospermopsin MeSH Browser
• Extracellular Signal-Regulated MAP Kinases MeSH
• Carcinogens MeSH
• Complex Mixtures MeSH
• Microcystins MeSH
• Mitogen-Activated Protein Kinases MeSH
• Cyanobacteria Toxins MeSH
• Uracil MeSH

Cyanobacterial blooms in freshwaters represent a major ecological and human health problem worldwide. This paper briefly summarizes information on major cyanobacterial toxins (hepatotoxins, neurotoxins etc.) with special attention to microcystins-cyclic heptapeptides with high acute and chronic toxicities. Besides discussion of human health risks, microcystin ecotoxicology and consequent ecological risks are also highlighted. Although significant research attention has been paid to microcystins, cyanobacteria produce a wide range of currently unknown toxins, which will require research attention. Further research should also address possible additive, synergistic or antagonistic effects among different classes of cyanobacterial metabolites, as well as interactions with other toxic stressors such as metals or persistent organic pollutants.

• Keywords
• cylindrospermopsin, ecotoxicology, microcystin, peptide toxins, tumor promotion,
• Publication type
• Journal Article MeSH