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Evidence for a covalently bound form of microcystin-LR in salmon liver and dungeness crab larvae

TitleEvidence for a covalently bound form of microcystin-LR in salmon liver and dungeness crab larvae
Publication TypeJournal Article
Year of Publication1997
AuthorsWilliams, DE, Craig, M, Dawe, SC, Kent, ML, Holmes, CFB, Andersen, RJ
JournalChemical Research in Toxicology
Volume10
Pagination463-469
Date PublishedApr
Type of ArticleArticle
ISBN Number0893-228X
KeywordsBLUE-GREEN-ALGAE, CYCLIC, DIARRHETIC SHELLFISH TOXINS, DIHYDROMICROCYSTIN-LR, HEPATOCELLULAR, OKADAIC ACID, PEPTIDE TOXIN, PROTEIN PHOSPHATASE INHIBITORS, RAT-LIVER, TISSUE DISTRIBUTION, TUMOR PROMOTION, UPTAKE
Abstract

The chemically unique nature of the C-20 beta-amino acid (2S,3S,8S,9S)-3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoi c acid (Adda) portion of the microcystins has been exploited to develop a strategy to analyze for the total microcystin-1R (1; see Figure 1) burden in salmon liver and crab larvae tissues. Lemieux oxidation of microcystin-LR (1) gives 2-methyl-3-methoxy-4-phenylbutanoic acid (2), a unique marker for the presence of microcystins. The butanoic acid 2 can be isolated and detected by GC/MS from the livers of Atlantic salmon that received an ip injection of microcystin-1R (1) and from tissues of wild-caught crab larvae. The Lemieux oxidation-GC/MS results are compared with those from MeOH extraction-PPase analysis. Only similar to 24% of the total microcystin-1R (1) burden in salmon liver tissue is found to be extractable with MeOH. Similarly, the Lemieux oxidation-GC/MS method detected 10 000-fold greater microcystin concentrations in Cypress Island Dungeness crab larvae than did the MeOH extraction-PPase method. The disparity in microcystin concentrations measured by the two methods is taken as direct evidence for the existence of covalently bound microcystins in vivo.

URL<Go to ISI>://A1997WU38500017