Detecção de Microcystis potencialmente tóxicas em reservatórios de Pernambuco, através de marcadores moleculares para o operon da sintetase da microcistina - mcyB e mcyA

Abstract

Cyanobacterias or cyanoficeas, even they have many similarities with eukariotics seaweed and occupy the same ambient niches, they belong to the Eubactéria domain. In Brazil, the occurrence of blooms of cyanobacterias was evidenced, mainly in the state of Pernambuco, where some patients died in 1996. Amongst the cyanobacterias capable of producing toxins, the Genus Microcystis is distinguished; being required some genes (mcyA the J) for toxin production. This work has the objective to verify the presence of operon for the genes, mcyB and mcyA, in populations of cyanobacterias in the reservoirs of the state of Pernambuco. The taxonomic survey of the reservoirs made possible the identification of 16 taxon represented by three orders: Chroococcales; Nostocales and Oscilatoriales, which M. aeruginosa was more widely distributed species in the studied reservoirs. The reservoir of the Agreste was the one where could be found the biggest number of organisms for L-1 with the value of 51,423,078 L-1, followed by reservoirs of Sertão and Zona da Mata. Operon of the ficocianine, proved the presence of cyanobacterias for all the studied reservoirs. The gene of mcyB was presented for all reservoirs. The mcyA only for the Tapacurá reservoir in the rainy period, representing for 11,11% of the samples. Amongst the primers employed for mcyB, mcyB-FR demonstrated to be more specific than mcyB-FRA, not showing unexpected bands. The assays in HPLC had performed so far only for two reservoirs, Arcoverde and Jazigo in rainy season, being positive only for the Jazigo reservoir. The results demonstrate the necessity for a periodic monitoring in the Pernambuco’s reservoirs state emphasized for the potentially toxic cyanobacterias, as PCR an appropriate method with respect to the detention of potentials microcystins producer in environment samples.