Abstract
Cyanobacteria are relevant components of phytoplankton and can be found in a large number of Brazilian reservoirs. Some species can produce potent toxins (eg.: microcystins, saxitoxin, cylindrospermopsin, anatoxin, among others) with distinct biological activities. Especially in eutrophic environments, these microorganisms can present a rapid growth, a phenomenon known as bloom, which can affect the quality of drinking water and recreation. In northeastern Brazil, the bloom problem is powered by water regime, with intense periods of drought, a condition that requires a large number of reservoirs and long period of residence, favoring its occurrence. Due to the lack of molecular estudies in northeastern reservoirs, this proposal aim to evaluate the cyanobacterial metagenomic structure from blooms in Ingazeira and Mundaú reservoirs, regarding their potencil for cyanotoxin production, based on culture-independent methods. This study also aims to complement the work already undertaken in these environments and, thus, the samples are already available for analysis. PCR products will be obtained by PCR amplification (Polymerase Chain Reaction) from both 16S-23S rRNA intergenic spacer region (ITS) and cpcBA-IGS region of phycocyanin (PC) operon using genomic DNA. The toxicological potential of the blooms will be assessed by amplification of genes involved in the biosynthesis of microcystin (mcyE gene), saxitoxins (sxtA gene), and cylindrospermopsins (cyrJ gene). The amplicons will be purified and used for metagenomic sequencing by Illumina MiSeq system. The sequences produced will be compared by BLAST analysis (NCBI) and their evolutionary relationships will be established by the construction of phylogenetic trees. The cyanotoxins production will be verified by HPLC. This proposal represents the first metagenomic study of cyanobacteria in Brazilian reservoirs, and aims to generate innovative studies on molecular ecology at the Laboratory of Cyanobacteria from ESALQ/USP, introducing a new approach. The project will run for two years and establish a close collaboration with the Federal Rural University of Pernambuco, where taxonomic studies and floristic analysis about cyanobacterial occurrence in Pernambuco State were already done. This project will enable the publication of scientific articles focused on cyanobacterial molecular ecology and public health. (AU)
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