title: Molecular identification and evolution of the cyclic peptide hepatotoxins, microcystin and nodularin, synthetase genes in three orders of cyanobacteria.
abstract: The cyanobacterial hepatotoxins, microcystin and nodularin, are produced by a wide range of cyanobacteria. Microcystin production has been reported in the four cyanobacterial orders: Oscillatoriales, Chroococcales, Stigonematales, and Nostocales. The production of nodularin is a distinct characteristic of the Nostocales genus Nodularia. A single rapid method is needed to reliably detect cyanobacteria that are potentially capable of producing these hepatotoxins. To this end, a PCR was designed to detect all potential microcystin and nodularin-producing cyanobacteria from laboratory cultures as well as in harmful algal blooms. The aminotransferase (AMT) domain, which is located on the modules mcyE and ndaF of the microcystin and nodularin synthetase enzyme complexes, respectively, was chosen as the target sequence because of its essential function in the synthesis of all microcystins as well as nodularins. Using the described PCR, it was possible to amplify a 472 bp PCR product from the AMT domains of all tested hepatotoxic species and bloom samples. Sequence data provided further insight into the evolution of the microcystin and nodularin synthetases through bioinformatic analyses of the AMT in microcystin and nodularin synthetases, with congruence between the evolution of 16S rRNA and the AMT domain.
authors.affiliation: School of Biotechnology and Biomolecular Sciences, The University of New South Wales, 2052, Sydney, NSW, Australia.
authors.forename: Anne-Dorothee
authors.initials: AD
authors.lastname: Jungblut
authors.forename: Brett A
authors.initials: BA
authors.lastname: Neilan
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001427:Bacterial Toxins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D000458:Cyanobacteria / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D052998:Microcystins / Q000378:metabolism; D008969:Molecular Sequence Data; D010453:Peptide Synthases / Q000235:genetics* / Q000378:metabolism; D010456:Peptides, Cyclic / Q000378:metabolism; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004269:DNA, Bacterial; D052998:Microcystins; D010456:Peptides, Cyclic; C063998:nodularin; D010453:Peptide Synthases; C432283:microcystin synthetase A