Antiangiogenic, antimicrobial, and cytotoxic potential of sponge-associated bacteria.

The bacteria associated with marine invertebrates are a rich source of bioactive metabolites. In the present study bacteria associated with the sponge Suberites domuncula and its primmorphs (3-dimensional aggregates containing proliferating cells) were isolated and cultured. These bacteria were extracted, and the extracts were assayed for antiangiogenic, hemolytic, antimicrobial, and cytotoxic activities. Our studies revealed that extract obtained from the bacterium (PB2) isolated from sponge primmorphs is a potent angiogenesis inhibitor. In the chick chorio-allantoic membrane (CAM) assay, it showed 50% activity at 5 microg ml(-1) and 100% activity at 10 and 20 microg ml(-1) concentrations. Extracts obtained from 5 bacterial strains isolated from sponge and its primmorphs showed hemolytic activity. The sponge-associated bacteria belonging to the alpha subdivision of Proteobacteria and the primmorph-associated bacterium identified as a possible novel Pseudomonas sp. displayed remarkable antimicrobial activity. It is important to note that these bacterial extracts were strongly active against multidrug-resistant clinical strains such as Staphylococcus aureus and Staphylococcus epidermidis, isolated from hospital patients. The bacterial extracts having antimicrobial activity also showed cytotoxicity against HeLa and PC12 cells. In summary, this investigation explores the importance of sponge-associated bacteria as a valuable resource for the discovery of novel bioactive molecules.