Antagonistic Interactions among Bacteria Isolated from either the Same or from Different Sponges Native to the Brazilian Coast

Abstract

Marine sponges are sessile and filter-feeding organisms that harbor dense and diverse microbial communities of considerable ecological and biotechnological importance. They represent an important target for the study of bacterial interactions in marine ecosystems. The purpose of this study was to examine the frequency of antagonistic interactions among the culturable microbial communities associated with sponges from the Brazilian coast. The specimens were collected over six years at Cagarras Archipelago, Praia Vermelha Beach and Urca square, Rio de Janeiro State, SE Brazil. Fifty-six bacterial isolates representing four classes of cultivable sponge-associated bacteria were studied for their ability to produce inhibitory substances. Antagonistic interactions occurred among isolates from both, the same and different sponge species. Most isolates (98.2%) were able to inhibit growth of at least one indicator bacterium. In contrast, there were few antagonistic interactions among bacteria obtained from the same sponge specimen. Our results suggest that chemical antagonism could play a significant role in shaping the bacterial communities within sponge tissues.