TITLE:
Molecular and Chemical Analyses of Cyanobacterial Blooms in Tropical Lagoons from Southeast Brazil
AUTHORS:
Luciana Mecatti Elias, Maria Estela Silva-Stenico, Danillo Oliveira Alvarenga, Janaina Rigonato, Marli Fátima Fiore, Simone Possedente de Lira
KEYWORDS:
Cyanobacteria, Bloom, Cyanotoxins, Lagoons, Microcystis
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.7 No.1,
January
21,
2015
ABSTRACT: The genetic
diversity and the potential toxicity of bloom-forming cyanobacteria were studied
in four lagoons located in the state of Sao Paulo (Campinas, Limeira and Piracicaba
cities). Bloom samples were collected on the water surface and cyanobacterial communities
were evaluated using DGGE fingerprinting and 16S rDNA clone library. The amplification
of genes encoding secondary metabolites such as microcystin (mcy), anatoxin (ana), cylindrospermopsin (cyr), saxitoxin (sxt), cyanopeptolin (mcn) and aeruginosin (aer) was performed
and their production analyzed by LC-MS. The comparison of DGGE banding pattern among
the different water samples suggested that some operational taxonomic units (OTUs)
in these locations were predominant over others. The 16S rDNA clone libraries sequences
matched with nine different known cyanobacterial genera available in NCBI, identified
as Anabaena, Brasilonema, Cylindrospermopsis, Limnococcus, Microcystis, Nostoc, Pseudanabaena, Synechococcus and Woronichinia.
The lagoons ESALQ2, Taquaral and Limeira had more than 80% of the cyanobacterial
community assigned to the genus Microcystis.
Genes encoding aeruginosin, cyanopeptolin and microcystin synthetases and saxitoxin
synthase were amplified, and LC-MS/MS confirmed the production of aeruginosin, cyanopeptolin
and microcystin. Rapid and sensitive methods for the detection of these secondary
metabolites, especially toxins, using chemical and molecular tools together, can
be used for a faster diagnostic of toxic cyanobacterial blooms.