Avaliação da diversidade taxonômica e potencial biotecnológico de bactérias isoladas de moluscos teredinídeos do Manguezal Coroa Grande-RJ

Abstract

The search for molecules with biological activity from the Brazilian biodiversity, is increasingly, including the research related to natural marine products aiming the development of drugs. Microorganisms are part of numerous ecological niches, and the symbionts microorganisms of marine invertebrates harbor countless bioactive natural products that remains barely explored. The genome sequencing of Teredinibacter turnerae, a symbiont species with molluscs of the family Teredinidae, revealed a great biotechnological potential of these bacteria. This species has a large number of enzymes capable of degrading cellulose, as well as a unique gene pool for the synthesis of potentially bioactive natural products. The objectives of this work were to evaluate the taxonomic diversity of the microbiota of these molluscs as well as to evaluate the antiproliferative activity in tumor cells and antimicrobial in bacterial lines indicative of extracts produced by bacteria isolated from teredinidae molluscs. To obtain and amplify the 16S rRNA the colony PCR method was used and the obtained amplicons were purified using ExoSap and performed first generation sequencing. Crude extracts were obtained using organic solvent ethyl acetate. Antiproliferative activity was assessed by SRB assay using human colorectal cancer cell line (HCT 116) and antimicrobial effect by broth microdilution assay using Escherichia coli and Staphylococcus aureus as Gram – and Gram + indicator strains respectively. For antitumor potential initial screening, the extracts at 50 µg/mL after 72h incubation which induced cellular growth inhibition > 75% were considered active. For the antibacterial effect, the extracts at 0.5 or 1.0 mg/mL after 19h incubation which induced growth inhibition > 50% were considered active. 41 bacteria isolated from Neoteredo reynei and Nausitora fusticula from the MicroMarin microorganism inventory (www.labbmar.ufc.br/micromarin) were activated and cultivated in Petri dishes with shipworm basal media containing cellulose (SBM-C). The 15 samples with quality sequencing showed 100% similarity with the genus Teredinibacter. 24 crude extracts were prepared and 83% depicted antiproliferative activity against HCT 116. 40% of the 22 crude extracts tested were depicted antibacterial activity. The crude extract of the BRA-646 strain depicted the higher antiproliferative potency, presenting mean inhibitory concentration = 7,5 µg/mL, total inhibitory concentration = 17,1 µg/mL and mean lethal concentration = 38,8 µg/ml. While 9 extracts were active against E. coli and 3 were active against S. aureus. The cultivable microbiota of N. reynei and N. fusticula teredinid molluscs is a rich source of substances with antiproliferative and antimicrobial activity.