Affiliation:
1. Laboratoire Charles Friedel, UMR CNRS 7223, ENSCP ChimieParisTech, 11 Rue Pierre et Marie Curie, 75231 Paris Cedex 05, France
2. Université Paris Diderot-Paris 7, 75013 Paris, France
3. Laboratoire Environnement et Chimie Analytique, UMR PECSA CNRS 7195, ESPCI ParisTech, 10 Rue Vauquelin, 75231 Paris Cedex 05, France
Abstract
ABSTRACT
Cylindrospermopsin is a cytotoxin produced by
Cylindrospermopsis raciborskii
and other cyanobacteria that has been implicated in human intoxications. We report here the complete sequence of the gene cluster responsible for the biosynthesis of this toxin in
Oscillatoria
sp. strain PCC 6506. This cluster of genes was found to be homologous with that of
C. raciborskii
but with a different gene organization. Using an enzyme-linked immunosorbent assay and an optimized liquid chromatography analytical method coupled to tandem mass spectrometry, we detected 7-epicylindrospermopsin, cylindrospermopsin, and 7-deoxycylindrospermopsin in the culture medium of axenic
Oscillatoria
PCC 6506 at the following relative concentrations: 68.6%, 30.2%, and 1.2%, respectively. We measured the intracellular and extracellular concentrations, per mg of dried cells of
Oscillatoria
PCC 6506, of 7-epicylindrospermopsin (0.18 μg/mg and 0.29 μg/mg, respectively) and cylindrospermopsin (0.10 μg/mg and 0.11 μg/mg, respectively). We showed that these two toxins accumulated in the culture medium of
Oscillatoria
PCC 6506 but that the ratio (2.5 ± 0.3) was constant with 7-epicylindrospermopsin being the major metabolite. We also determined the concentrations of these toxins in culture media of other
Oscillatoria
strains, PCC 6407, PCC 6602, PCC 7926, and PCC 10702, and found that, except for PCC 6602, they all produced 7-epicylindrospermopsin and cylindrospermopsin, with the former being the major toxin, except for PCC 7926, which produced very little 7-epicylindrospermopsin. All the cylindrospermopsin producers studied gave a PCR product using specific primers for the amplification of the
cyrJ
gene from genomic DNA.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
118 articles.
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