Characterization of a microcystin and detection of microcystin synthetase genes from a Brazilian isolate of Nostoc

Autor(es)

Genuario, Diego Bonaldo ^[1] ; Silva-Stenico, Maria Estela ^[1] ; Welker, Martin ^[2] ; Beraldo Moraes, Luiz Alberto ^[3] ; Fiore, Marli Fatima ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Ctr Nucl Energy Agr, BR-13400970 Piracicaba, SP - Brazil

^[2] Tech Univ Berlin, FG Umweltmikrobiol, D-10587 Berlin - Germany

^[3] Univ Sao Paulo, FFCLRP, Dept Chem, BR-14049 Ribeirao Preto, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Toxicon; v. 55, n. 4, p. 846-854, APR 1 2010.
• Citações Web of Science: 18

Resumo

A nostocalean nitrogen-fixing cyanobacterium isolated from an eutrophic freshwater reservoir located in Piracicaba, Sao Paulo, Brazil, was evaluated for the production of hepatotoxic cyclic heptapeptides, microcystins. Morphologically this new cyanobacterium strain appears closest to Nostoc, however, in the phylogenetic analysis of 165 rRNA gene it falls into a highly stable cluster distantly only related to the typical Nostoc cluster. Extracts of Nostoc sp. CENA88 cultured cells, investigated using ELISA assay, gave positive results and the microcystin profile revealed by ESI-Q-TOF/MS/MS analysis confirmed the production of {[}Dha(7)]MCYST-YR. Further, Nostoc sp. CENA88 genomic DNA was analyzed by PCR for sequences of mcyD, mcyE and mcyG genes of microcystin synthetase (mcy) cluster. The result revealed the presence of mcyD, mcyE and mcyG genes with similarities to those from mcy of Nostoc sp. strains 152 and IO-102-I and other cyanobacterial genera. The phylogenetic tree based on concatenated McyG, McyD and McyE amino acids clustered the sequences according to cyanobacterial genera, with exception of the Nostoc sp. CENA88 sequence, which was placed in a clade distantly related from other Nostoc strains, as previously observed also in the 165 rRNA phylogenetic analysis. The present study describes for the first time a Brazilian Nostoc microcystin producer and also the occurrence of demethyl MCYST-YR variant in this genus. The sequenced Nostoc genes involved in the microcystin synthesis can contribute to a better understanding of the toxigenicity and evolution of this cyanotoxin. (C) 2009 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 07/06360-8 - Caracterização genética de cianobactérias isoladas de manguezais do Estado de São Paulo usando seqüências de nucleotídeos nifH e cpcBA-IGS
• Beneficiário: Diego Bonaldo Genuário
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 04/16042-5 - Nanotecnologia: observação das estruturas formadas pela interação entre peptídeos não-ribossômicos, mutantes de metalotioneínas e lotioneinas e metais
• Beneficiário: Maria Estela Stenico
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado