The marine environment contains 75% of all organisms, making it an exciting resource for the discovery of unknown bioactive agents that may have therapeutic effects. Marine bacteria play a major role in their environment, affecting numerous ecological processes. Their intercellular communication processes, termed Quorum Sensing (QS), controls the behaviors of these bacteria affecting pathogenesis, symbiosis, motility and biofilm formation that are linked to 65% of all infectious disease. Processes of QS and its inhibition (QSI) mechanisms are important in attenuating bacterial populations with respect to virulence and pathogenicity. In contrast to bacterial antibiotic resistance development, QSI may act on certain bacterial populations without affecting the bacterial growth, minimizing the selective pressure, and are thus less likely to impose a selective pressure that leads to resistance. Since, to date, bacterial screening for bioactive agents is limited by our ability to culture the relevant bioactive bacteria, we suggest a new in-situ culture and QSI screening technique. To illustrate this technique, coral Favia sp.mucus samples were encapsulated and in-situ incubated for 5 weeks in their natural habitat, then screened for QSI compounds produced by their bacteria consortium; the spheres containing bacterial consortia that showed QSI were 16S sequenced and subsequent phylogenetic analysis. In addition, these spheres were reproduced into new spheres to obtain large numbers of spheres with QSI activities necessary to provide enough material for chemical analysis. Using MS, a putative active QS molecule with a precursor m/z 371 was detected and its molecular structure is currently being elucidated.
