Cylindrospermopsin and Saxitoxin Synthetase Genes in Cylindrospermopsis raciborskii Strains from Brazilian Freshwater

Autor(es)

Hoff-Risseti, Caroline ^[1] ; Doerr, Felipe Augusto ^[2] ; Carvalho Schaker, Patricia Dayane ^[3] ; Pinto, Ernani ^[4] ; Werner, Vera Regina ^[5] ; Fiore, Marli Fatima ^[6]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo. Ctr Nucl Energy Agr

^[2] Univ Sao Paulo. Fac Pharmaceut Sci

^[3] Univ Sao Paulo. Ctr Nucl Energy Agr

^[4] Univ Sao Paulo. Fac Pharmaceut Sci

^[5] Zoobot Fdn Rio Grande Sul. Museum Nat Sci

^[6] Univ Sao Paulo. Ctr Nucl Energy Agr

• Tipo de documento: Artigo Científico
• Fonte: PLoS One; v. 8, n. 8 AUG 28 2013.
• Citações Web of Science: 28

Resumo

The Cylindrospermopsis raciborskii population from Brazilian freshwater is known to produce saxitoxin derivatives (STX), while cylindrospermopsin (CYN), which is commonly detected in isolates from Australia and Asia continents, has thus far not been detected in South American strains. However, during the investigation for the presence of cyrA, cyrB, cyrC and cyrJ CYN synthetase genes in the genomes of four laboratory-cultured C. raciborskii Brazilian strains, the almost complete cyrA gene sequences were obtained for all strains, while cyrB and cyrC gene fragments were observed in two strains. These nucleotide sequences were translated into amino acids, and the predicted protein functions and domains confirmed their identity as CYN synthetase genes. Attempts to PCR amplify cyrJ gene fragments from the four strains were unsuccessful. Phylogenetic analysis grouped the nucleotide sequences together with their homologues found in known CYN synthetase clusters of C. raciborskii strains with high bootstrap support. In addition, fragments of sxtA, sxtB and sxtI genes involved in STX production were also obtained. Extensive LC-MS analyses were unable to detect CYN in the cultured strains, whereas the production of STX and its analogues was confirmed in CENA302, CENA305 and T3. To our knowledge, this is the first study reporting the presence of cyr genes in South American strains of C. raciborskii and the presence of sxt and cyr genes in a single C. raciborskii strain. This discovery suggests a shift in the type of cyanotoxin production over time of South American strains of C. raciborskii and contributes to the reconstruction of the evolutionary history and diversification of cyanobacterial toxins. (AU)

• Processo FAPESP: 10/16328-7 - Sequenciamento do genoma da cianobactéria Microcystis aeruginosa SPC777
• Beneficiário: Marli de Fátima Fiore
• Modalidade de apoio: Auxílio à Pesquisa - Regular