RESUMO
Despite the broad assessment of sponge bacterial diversity through cultivation-independent and dependent strategies, the knowledge focusing on cultivable anaerobes from this holobiont is still incipient. Plakina is a genus with the highest number of described species from the smallest of poriferan classes, Homoscleromorpha. The Brazilian Atlantic coast has been presenting itself as a hotspot for the discovery of new plakinidae species, with initial surveys just now concerning to characterize their microbiome. The current study aimed to isolate and identify strict anaerobes from recently described species of Plakina collected at the coast of Cabo Frio, RJ. Samples of four sympatric morphotypes of Plakina cyanorosea and Plakina cabofriense were collected on the coast of Cabo Frio, RJ. Using five different culture media, a total of 93 bacterial isolates were recovered, among which 60 were strict anaerobes and, ultimately, 34 remaining viable. A total of 76.5% from these strains were mostly identified as Clostridium bifermentans by mass spectrometry and 82.4% identified by 16S rRNA sequencing, almost all of them affiliated to the genus Paraclostridium, and with one isolate identified as Clostridium butyricum by both techniques. None of the anaerobic bacteria exhibited antimicrobial activity by the adopted screening test. The present work highlights not only the need for cultivation and characterization of the anaerobic microbiota from marine sponges but also adds the existing scarce knowledge of culturable bacterial communities from Homoscleromorph sponges from Brazilian coast.
Assuntos
Bactérias Anaeróbias/classificação , Bactérias Anaeróbias/isolamento & purificação , Clostridiales/classificação , Clostridiales/isolamento & purificação , Poríferos/microbiologia , Aerobiose , Anaerobiose , Animais , Anti-Infecciosos/metabolismo , Organismos Aquáticos/microbiologia , Oceano Atlântico , Bactérias Anaeróbias/química , Bactérias Anaeróbias/genética , Técnicas Bacteriológicas , Brasil , Clostridiales/química , Clostridiales/genética , Clostridium bifermentans , Clostridium butyricum , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Espectrometria de Massas , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Sponges offer an excellent model to investigate invertebrate-microorganism interactions. Furthermore, bacteria associated with marine sponges represent a rich source of bioactive metabolites. The aim of this study was to characterize the bacteria inhabiting a genus of sponges, Oscarella, and their potentiality for antimicrobial production. Bacterial isolates were recovered from different Oscarella specimens, among which 337 were phylogenetically identified. The culturable community was dominated by Proteobacteria and Firmicutes, and Vibrio was the most frequently isolated genus, followed by Shewanella. When tested for antimicrobial production, bacteria of the 12 genera isolated were capable of producing antimicrobial substances. The majority of strains were involved in antagonistic interactions and inhibitory activities were also observed against bacteria of medical importance. It was more pronounced in some isolated genera (Acinetobacter, Bacillus, Photobacterium, Shewanella and Vibrio). These findings suggest that chemical antagonism could play a significant role in shaping bacterial communities within Oscarella, a genus classified as low-microbial abundance sponge. Moreover, the identified strains may contribute to the search for new sources of antimicrobial substances, an important strategy for developing therapies to treat infections caused by multidrug-resistant bacteria. This study was the first to investigate the diversity and antagonistic activity of bacteria isolated from Oscarella spp. It highlights the biotechnological potential of sponge-associated bacteria.