Meeting Abstract

P2.20  Tuesday, Jan. 5  Potential resistance of Antarctic ascidians to sympatric bacterial epibiosis KOPLOVITZ, G*; MCCLINTOCK, J.B.; AMSLER, C.D.; BAKER, B.J.; University of Alabama at Birmingham; University of Alabama at Birmingham; University of Alabama at Birmingham; University of South Florida gilkop@uab.edu

Both biotic and abiotic surfaces in benthic marine environments are subject to fouling by bacteria, protists and macroinvertebrate larvae. Although in certain circumstances epibiosis may be beneficial to the basibiont (the organism being fouled), for example, through the provision of vitamins and nitrogenous compounds, by in large, fouling is more harmful than beneficial. A large variety of fouling organisms are commonly found on the surfaces (tunic) of ascidians. These include bacteria, algae (such as diatoms), bryozoans and hydroids, as well as other macroinvertebrates. The focus of this study was to assess the incidence of antimicrobial activity in both lipophilic and hydrophilic crude organic extracts of a suite of solitary and colonial ascidians from the western Antarctic Peninsula. The bacterial strains tested were isolated from both the water-column and from the surfaces of sympatric benthic marine invertebrates. Antimicrobial activity of extracts from 13 species of Antarctic ascidians was evaluated using 20 strains of sympatric marine bacteria. Bacterial strains were tested using standard microbial growth inhibition techniques. Paper antimicrobial assay disks treated with ascidian solubilized extract were placed onto inoculated marine agar plates. Each plate was incubated at 4°C for several days until bacterial growth was visible and zones of inhibition could be measured. Zones of growth inhibition were compared to solvent control disks in order to evaluate antimicrobial activity of ascidian extracts. The results of this analysis will be interpreted in light of the prospective impacts of fouling in ascidians. This research was supported by NSF grants # OPP-0442769 and OPP-0442857.