| Congresso Brasileiro de Microbiologia 2023 | Resumo: 932-1 | ||||
Resumo:Cyanobacteria are photosynthetic microorganisms known for their rich molecular repertoire, which includes an enormous diversity of bioactive compounds with elevated biotechnological potential. Despite the expressive number of molecules already described by these photosynthetic beings, new molecules have been constantly discovered. The Amazon region is formed by environments which are very suitable for the development of cyanobacteria. However, it has been little explored. For that, in this work, cyanobacteria isolated from different Amazon environments were analyzed for their cytotoxic, antimicrobial and allelopathic activities. The cytotoxicity activity was evaluated through MTT method using aqueous and organic extracts obtained from the biomass as well fractions acquired from the MeOH extract applying a water and acetonitrile gradient. One fraction of the strain Synechocystis sp. CACIAM 05 exhibited the highest potency against hCMEC and MG-63 cell lines. A metabolic analysis employing tools from GNPS and the databases Dictionary of Natural Products and CyanoMetDB allowed the identification of these compounds as pheophytin and phorbide derivatives. In the antimicrobial assay, none of the fractions were bioactive against the yeast Candida tropicalis and the gram-negative bacterium Salmonella typhimurium ATCC 14021. However, a different fraction from the strain Synechocystis sp. CACIAM 05 showed bactericide activity with a minimum inhibitory concentration (MIC) and minimum bactericidal concentration values of 40 and 80 µg mL-1, respectively. Fractions from other strains (Desmonostoc sp. CACIAM 45 and Synechococcus sp. CACIAM 66) also exhibited antibacterial activity against Bacillus subtilis ATCC 6633, but with higher MIC values. For the allelopathic assay, a superior number of strains were investigated through the cocultivation in solid medium technique with the target cyanobacterium Synechococcus sp. CACIAM 66. A total of 11 cyanobacterial strains demonstrated inhibitory activity with distinct inhibition zones. Nostoc sp. CACIAM 21 and a filamentous, non-heterocystous unidentified strain (CACIAM 53) offered the highest inhibitory zones with 30.84 and 47.43 mm, respectively. Both microorganisms demonstrated the production of allelochemicals with distinct chemical property. An interesting synergism was observed for the strain Desmonostoc sp. CACIAM 45 and Synechocystis sp. CACIAM 05. When tested separately, they failed in offering any inhibitory activity while when mixed showed antagonistic activity against Synechococcus sp. CACIAM 66. In general, the cyanobacteria investigated here showed to be quite promising for some type of activity. Future studies will allow a better comprehension of the action mechanism of these microorganisms as well as their chemical composition. Palavras-chave: Cyanobacteria, Biotechnology, Cytotoxicity, Allelopathy, Antimicrobial activity Agência de fomento:Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Fundação Amazônia Paraense de Amparo a Estudos e Pesquisas (FAPESPA) e Pró-Reitoria de Inclusão e Pertencimento da Universidade de São Paulo. | |||||