Isolation and identification of 12 microcystins from four strains and two bloom samples of Microcystis spp.: structure of a new hepatotoxin

Luukkainen, Raija; Namikoshi, Michio; Sivonen, Kaarina; Rinehart, Kenneth L.; Niemelä, Seppo

doi:10.1016/0041-0101(94)90030-2

Cited by 75 publications

(34 citation statements)

References 41 publications

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“…The fact that MC-YR appears in trace amounts in natural samples of water and in cyanobacterial blooms extracts was confirmed in cultures assays with different strains of Microcystis viridis [65]. In contrast, Finnish Microcystis blooms contained mainly desmethylated variants of MC-LR, MC-RR and MC-YR [66]. In central Spain, a demethylated variant of MC-RR was identified as the major microcystin in most samples [67].…”

Section: Discussionmentioning

confidence: 96%

Cyanobacteria and microcystins occurrence in the Guadiana River (SW Spain)

Moreno

Repetto

Carballal

et al. 2005

International Journal of Environmental Analytical Chemistry

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This work reports on the survey carried out to determine the presence of microcystins (MCs) by using ELISA tests and HPLC-UV for such determination in different sample sites along the Spanish course of the Guadiana River. The most important cyanobacteria species identified were, Microcystis aeruginosa and Oscillatoria spp. The highest total microcystin content recorded was 6.40 mg L À1 in 2002. The main toxins found were microcystins RR and LR, with microcystin YR present at trace levels. Improvements in sample clean up were carried out by using Immunoaffinity solid phase extraction (SPE) and its advantages regarding to conventional SPE were clearly demonstrated. The confirmation of MCs presence in the evaluated water reservoirs, underlines the necessity of monitoring programs as well as the improvement of analytical methodologies to efficiently prevent the human health risks as a consequence of MCs contamination.

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Section: Discussionmentioning

confidence: 96%

Cyanobacteria and microcystins occurrence in the Guadiana River (SW Spain)

Moreno

Repetto

Carballal

et al. 2005

International Journal of Environmental Analytical Chemistry

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“…While certain species can also produce neurotoxins, M. aeruginosa is most commonly known to produce the hepatotoxic heptapeptide microcystin in a variety of forms with varying toxicity (18,28). Microcystin binds to the multispecific bile acid transport system, subsequently directing toxic effects to hepatocytes (29).…”

mentioning

confidence: 99%

Light and the Transcriptional Response of the Microcystin Biosynthesis Gene Cluster

Kaebernick

Neilan

Börner³

et al. 2000

Appl Environ Microbiol

351

268

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Microcystin, a hepatotoxin known to be the cause of animal and human deaths, is produced by the bloom-forming cyanobacterium Microcystis aeruginosa in freshwater bodies worldwide. The toxin is produced nonribosomally via a multifunctional enzyme complex, consisting of both peptide synthetase and polyketide synthase modules coded for by the mcy gene cluster. The recent identification of the mcy genes in the production of microcystin synthetase for the first time provides an avenue to study the regulation of microcystin production at a genetic level. In this study, M. aeruginosa PCC7806 was grown either under continuous light of various intensities or under low light with subsequent short-term exposure to different light intensities and qualities and various stress factors. RNase protection assays were employed to observe the level of mcyB and mcyD transcription under each condition. Both mcyB and mcyD transcript levels were increased under high light intensities and red light. Blue light and certain artificial stress factors (methylviologen and NaCl) led to reduced transcript amounts. There appeared to be two light thresholds, between dark and low light (16 mol of photons m ؊2 s ؊1 ), and medium (31 mol of photons m ؊2 s ؊1 ) and high light (68 mol of photons m ؊2 s ؊1 ), at which a significant increase in transcription occurred. Our findings show that the effect of light on microcystin synthetase production is due to light quality and is initiated at certain threshold intensities, which are not necessarily reflected by observed intracellular toxin bioactivity.

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“…More than 80 different structural variants of microcystins have been identified from various genera of cyanobacteria (Luukkainen et al, 1994;Lawton et al, 1995;Welker and von Döhren, 2006 (3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca; 4,6-dienoic acid) and six other amino acids, including two variable positions that designate the congener. The most extensively studied, microcystin-LR, has been found worldwide and has caused acute, lethal hepatotoxicoses in farm animals (Carbis et al, 1994;Mez et al, 1997;Puschner et al, 1998) and hepatic injury in humans (Azevedo et al, 2002;Rao et al, 2002).…”

Section: Microcystinsmentioning

confidence: 99%