Journal ArticleDOI
Structure and biosynthesis of toxins from blue-green algae (cyanobacteria)
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TLDR
Nearly 30 new microcystins have been isolated in the laboratory from cyanobacteria species and their structures assigned, largely employing tandem FAB mass spectrometry (FABMS/CID/MS) and numerous analogs identified or synthesized allow the identification of important parameters in a structure-activity relationship study.Abstract:
Microcystis andNodularia species produce cyclic hepta- and pentapeptides, microcystins and nodularin, respectively, both containing the same unusual C20 amino acid, abbreviated Adda. Biosynthesis of nodularin fromNodularia and especially of Adda employs a pathway similar to that employed byMicrocystis for producting microcystins. Nearly 30 new microcystins have been isolated in our laboratory from cyanobacteria species and their structures assigned, largely employing tandem FAB mass spectrometry (FABMS/CID/MS). Acyclic peptides, some of them presumed precursors of nodularin and microcystins, have now been isolated and characterized. The numerous analogs identified or synthesized allow the identification of important parameters in a structure-activity relationship study.read more
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The Ecology of Phytoplankton
TL;DR: Reynolds as discussed by the authors provides basic information on composition, morphology and physiology of the main phyletic groups represented in marine and freshwater systems and reviews recent advances in community ecology, developing an appreciation of assembly processes, co-existence and competition, disturbance and diversity.
Journal ArticleDOI
Human Fatalities from Cyanobacteria: Chemical and Biological Evidence for Cyanotoxins
Wayne W. Carmichael,Sandra M.F.O. Azevedo,Ji Si An,Renato J.R. Molica,Elise M. Jochimsen,Sharon Lau,Kenneth L. Rinehart,Glendon Reginald Shaw,Geoff Eaglesham +8 more
TL;DR: It is concluded that the major contributing factor to death of the dialyses patients was intravenous exposure to microcystins, specificallymicrocystin-YR, -LR, and -AR.
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Structural organization of microcystin biosynthesis in Microcystis aeruginosa PCC7806: an integrated peptide–polyketide synthetase system
TL;DR: This report is the first complete description of the biosynthesis pathway of a complex cyanobacterial metabolite and represents an integrated polyketide-peptide biosynthetic pathway with a number of unusual structural and enzyme features.
Journal ArticleDOI
Health Effects of Toxin-Producing Cyanobacteria: “The CyanoHABs”
TL;DR: The current understanding of CTP's including their risk to human health is reviewed to reflect the changing landscape of harmful algal blooms worldwide.
Journal ArticleDOI
A review of the global ecology, genomics, and biogeography of the toxic cyanobacterium, Microcystis spp.
Matthew J. Harke,Morgan M. Steffen,Christopher J. Gobler,Timothy G. Otten,Steven W. Wilhelm,Susanna A. Wood,Hans W. Paerl +6 more
TL;DR: The ability of Microcystis assemblages to minimize their mortality losses by resisting grazing by zooplankton and bivalves, as well as viral lysis, and discuss factors facilitating assemblage resilience are highlighted.
References
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Journal ArticleDOI
Cyanobacterial microcystin-LR is a potent and specific inhibitor of protein phosphatases 1 and 2A from both mammals and higher plants.
TL;DR: The cyclic heptapeptide, microcystin‐LR, inhibits protein phosphatases 1 (PP1) and 2A (PP2A) with K i, values below 0.1 nM, and this results are strikingly similar to those obtained with the tumour promoter okadaic acid.
Journal ArticleDOI
Liver tumor promotion by the cyanobacterial cyclic peptide toxin microcystin-LR.
Rie Nishiwaki-Matsushima,Tetsuya Ohta,Shinji Nishiwaki,Masami Suganuma,Kiyomi Kohyama,Takatoshi Ishikawa,Wayne W. Carmichael,Hirota Fujiki +7 more
TL;DR: In this paper, the authors showed that microcystin-LR, applied below the acute toxicity level, dose-dependently increases the number and percentage area of positive foci for the placental form of glutathioneS-transferase in rat liver, which was initiated with diethylnitrosamine.
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Inhibition of protein phosphatases by microcystins and nodularin associated with hepatotoxicity.
Shigeru Yoshizawa,Rie Matsushima,Mariyo F. Watanabe,Ken-ichi Harada,Akira Ichihara,Wayne W. Carmichael,Hirota Fujiki +6 more
TL;DR: The hepatotoxicity of microcystins and nodularin may result from inhibition of protein phosphatases and the increase of phosphoproteins, which is similar to that of okadaic acid in the nanomolar range of concentration.
Journal ArticleDOI
Characterization of microcystin-LR, a potent inhibitor of type 1 and type 2A protein phosphatases.
TL;DR: Microcystin-LR inhibited the activity of both type 1 and type 2A phosphatases greater than 10-fold more potently than okadaic acid under the same conditions and may prove to be a useful probe for the study and identification cellular processes which are mediated by protein phosphatase.
Liver tumor promotion by the cyanobacterial cyclic peptide toxin microcystin-LR. J Cancer Res Clin Oncol
Rie Nishiwaki-Matsushima,Tetsuya Ohta,Shinji Nishiwaki,Masami Suganuma,Kiyomi Kohyama,Takatoshi Ishikawa,Wayne W. Carmichael,Hirota Fujiki +7 more
TL;DR: It is shown that microcystin-LR, applied below the acute toxicity level, dose-dependently increases the number and percentage area of positive foci for the placental form of glutathioneS-transferase in rat liver, which was initiated with diethylnitrosamine.