Cyanobacteria from the caatinga biome: isolation, morphology, phylogeny and bioprospection

Abstract

This research project aims at accessing the molecular and genetic characteristics of cyanobacterial strains isolated from caatinga, through the analysis of morphometric characters, sequencing of the nifH gene from the nitrogenase complex - responsible by N2 fixation - and the 16S rRNA gene, used for cyanobacterial discrimination. The toxins (microcystin, cylindrospermopsin and saxitoxin) production will be analyzed by ELISA immunoassay and mass spectrometry. Furthermore, the presence of these toxin genes will be analyzed by PCR using the specific primers. The nucleotide sequences obtained will be compared to sequences from the NCBI database using the BLAST tool and the evolutionary distance between the nucleotides of the sequenced strains will be analyzed by phylogenetic tree construction. At least thirty cyanobacterial strains will be characterized. The estimate of the biological N2 fixation by these microorganisms will be analyzed using the acetylene reduction technique. The bioprospection with the isolated strains will be based on bioactivity and toxicity tests. Unknown compounds will be purified and characterized. We expect to obtain information about morphological, genetic and physiological diversity of the caatinga cyanobacteria with this study, contributing for a better comprehension about the role played by these microorganisms in this biome. Moreover, potential natural products with pharmaceutical and biotechnological interest will be identified and characterized.