Diversidade bacteriana e detecção de moléculas de interesse biotecnológico da microbiota cultivável de corais da costa brasileira por meio de estratégias genômicas e proteômicas

• Ano de defesa: 2024
• Autor(a) principal: Macedo, Maria Wanna Figueiredo Sena
• Orientador(a): Dias, Simoni Campos
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Católica de Brasília
• Programa de Pós-Graduação: Programa Stricto Sensu em Ciências Genômicas e Biotecnologia
• Departamento: Escola de Exatas, Arquitetura e Meio Ambiente
• País: Brasil
• Palavras-chave em Inglês: Millepora alcicornis; Mussismilia harttii; Phyllogorgia dilatata; Comunidade bacteriana; Prospecção; Potencial biotecnológico; Bacterial community; Prospection; Biotechnological potential
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS
• Link de acesso: https://bdtd.ucb.br:8443/jspui/handle/tede/3462

Marine microorganisms have been described as important sources that produce molecules involved in the recycling of organic compounds and new antimicrobial compounds. In this context, understanding marine bacterial diversity, as well as prospecting for antimicrobial agents and other metabolites synthesized by these organisms, can play a fundamental role in the development of biotechnological products. This work aims to identify bacterial isolates associated with reef cnidarians from the Brazilian coast and prospect for molecules of biotechnological interest, produced by these isolates, using genomic and proteomic techniques. In this study, three species of corals: Millepora alcicornis, Mussismilia harttii and Phyllogorgia dilatata, collected in Rio de Janeiro and Bahia, were macerated and plated in different culture media to obtain bacterial isolates using different isolation techniques. The bacterial isolates obtained were identified to the closest species level, through sequencing of the gene encoding 16S rRNA. For both the isolates from Rio de Janeiro and the isolates from Bahia, the majority presence of bacteria from the phylum Proteobacteria was observed, followed by Firmicutes. All isolates were evaluated for the prospection of genes involved in the synthesis of secondary metabolites, by amplification with specific primers, resulting in the identification of 37 bacterial isolates that present amplification with at least one of the primers. After screening all isolates for antimicrobial activity against Escherichia coli and Staphylococcus aureus, three isolates stood out for their activity, Mae 21, MHM 01 and PdM 01. These had their genome sequenced and their cultures subjected to fractionation with different organic solvents (SOs). SO II, composed of hexane and ethyl acetate, showed better results after the antimicrobial test, where SO II from the Mae 21 isolate was more prominent, being chosen for partial purification using liquid chromatography. New antimicrobial assays against S.aureus, Candida albicans and Candida krusei were carried out with SO II and the fractions generated in chromatography. The results of the antimicrobial tests show that the minimum inhibitory concentration (MIC) of fraction 9 was 300 μg.mL-1, being considered a moderate bioactivity (MIC of 126 to 500 μg.mL-1). However, the best results for this strain are related to its antitumor activity against PMC-42 and MDA-MB-231 mammary adenocarcinoma tumor cells. In this test, concentrations of 5, 10, 50, 100 and 200 μg.mL-1 were used, with a reduction in cell viability observed in treatments with SO II and fraction 9 at concentrations of 100 and 200 μg.mL-1, for PMC-42, and 5 μg.mL-1, for MDA-MB-231, showing significant differences when compared to the positive control. Furthermore, cytotoxicity tests using fibroblasts exposed to different concentrations of SO II and fraction 9 showed that cell viability remains above 90% when cells are treated with concentrations of up to 200 μg.mL-1, since they were not significant differences were found in treatments below this concentration. New experiments with the evaluation of other fractions must be carried out in search of the characterization of active compounds and with antitumor evaluation against other neoplastic cells.