Using Microcystin Gene Copies to Determine Potentially-Toxic Blooms, Example from a Shallow Eutrophic Lake Peipsi.

Global warming, paired with eutrophication processes, is shifting phytoplankton communities towards the dominance of bloom-forming and potentially toxic cyanobacteria. The ecosystems of shallow lakes are especially vulnerable to these changes. Traditional monitoring via microscopy is not able to quantify the dynamics of toxin-producing cyanobacteria on a proper spatio-temporal scale.

Identification of geosmin and 2-methylisoborneol in cyanobacteria and molecular detection methods for the producers of these compounds.

Geosmin and 2-methylisoborneol (MIB) are muddy/earthy off-flavor metabolites produced by a range of bacteria. Cyanobacteria are the major producers of the volatile metabolites geosmin and MIB which produce taste and odor problems in drinking water and fish worldwide. Here we detected geosmin and MIB by studying 100 cyanobacteria strains using solid phase microextraction gas chromatography mass spectrometry (SPME GC-MS).

Genome-derived insights into the biology of the hepatotoxic bloom-forming cyanobacterium Anabaena sp. strain 90.

Background: Cyanobacteria can form massive toxic blooms in fresh and brackish bodies of water and are frequently responsible for the poisoning of animals and pose a health risk for humans. Anabaena is a genus of filamentous diazotrophic cyanobacteria commonly implicated as a toxin producer in blooms in aquatic ecosystems throughout the world. The biology of bloom-forming cyanobacteria is poorly understood at the genome level.

Anatoxin-a synthetase gene cluster of the cyanobacterium Anabaena sp. strain 37 and molecular methods to detect potential producers.

Cyanobacterial mass occurrences are common in fresh and brackish waters. They pose a threat to water users due to toxins frequently produced by the cyanobacterial species present. Anatoxin-a and homoanatoxin-a are neurotoxins synthesized by various cyanobacteria, e.

Molecular methods: chip assay and quantitative real-time PCR: in detecting hepatotoxic cyanobacteria.

Cyanobacterial mass occurrences are widespread and often contain hepatotoxic, i.e. microcystin- and nodularin-producing, species.

Development of a chip assay and quantitative PCR for detecting microcystin synthetase E gene expression.

The chip and quantitative real-time PCR (qPCR) assays were optimized to study the expression of microcystin biosynthesis genes (mcy) with RNA samples extracted from cyanobacterial strains and environmental water samples. Both microcystin-producing Anabaena and Microcystis were identified in Lake Tuusulanjärvi samples. Microcystis transcribed the mcyE genes throughout the summer of 2006, while expression by Anabaena became evident later in August and September.