With culture-based and molecular methods, considerable progress has been made in characterizing the complex microbial communities associated with Key Largo sponges (Xestospongia muta, Ircinia strobilina, Axinella corrugata, Monanchora unguifera and Mycale laxissima), the sponge Microciona prolifera found in the Chesapeake Bay, and Xestospongia testudinaria from Indonesia.
- The sponges Ircinia strobilina and Mycale laxissima have been maintained in both flow-through and recirculating aquaculture systems (IMAGE) while changes in the microbial communities of these captive sponges have been continuously monitored.
- Predominant culturable isolates from all sponges have been identified, and molecular analysis of sponge-associated bacterial communities has revealed that that there are many novel bacteria present in sponges.
- One major finding has been the discovery that the microbial communities of Xestospongia spp. include many novel actinobacteria. These new members of the species fall in the little-studied subclass Acidimicrobidae. Four of these groups are found in the Xestospongia species with three of the four groups being found both in X. muta (Key Largo) and X. testudinaria (Indonesia). This suggests that these groups are true symbionts in these sponges and may play a common role in both the Pacific and Atlantic sponge species.
- Very few representatives of the Acidimicrobidae have previously been cultured, and Xestospongia spp. can now be targeted as source material from which to culture novel Acidimicrobidae.
- We have shown that some of these bacteria produce signaling compounds (acyl-homoserine lactone quorum sensing molecules) that may be important in complex relationships with the host sponges and their neighboring symbionts.
- Dr. Chen's lab has made progress in optimizing protocols for bacterial harvesting, protein extraction and purification. They have employed 2-D gel based proteomic approach in order to investigate protein expression patterns from five different species of sponges.
- Enticknap, J. J., M. Kelly Shanks, O. Peraud, and R. T. Hill. 2006. Characterization of a culturable alpha-proteobacterial symbiont common to many marine sponges and evidence for vertical transmission through the germline. Appl. Environ. Microbiol. (in press)
- Montalvo, N. F., N. M. Mohamed, J. J. Enticknap and R. T. Hill. 2005. Novel actinobacteria from marine sponges. Antonie van Leeuwenhoek. 87:29-36. Special volume on marine actinomycetes.
- Lohr, J. E., F. Chen and R. T. Hill. 2005. Genomic analysis and characterization of a marine phage that infects a sponge-associated alpha-Proteobacterium. Appl. Environ. Microbiol. 71:1598-1609.
- J. J. Enticknap, R. Thompson, O. Peraud, J. E. Lohr, M. T. Hamann and R. T. Hill. 2004. Molecular analysis of a Florida Keys sponge: Implications for natural products discovery. (Microsoft Word 25kB Apr24 06) Marine Biotechnol. 6:S288-293.
(see full list of publications supported by this MO grant)
Copyright on all images (except for those mentioned at top of page), and material by Russell Hill 2005.