Meeting Abstract
99.3 Sunday, Jan. 6 Predation response of Vibrio fischeri biofilms to protozoan bacteriovores CHAVEZ, A.A.*; GORMAN, C.; ERKEN, M.; MCDOUGALD, D.; STEINBERG, P.D.; NISHIGUCHI, M.K.; New Mexico State University; New Mexico State University; University of New South Wales; University of New South Wales; University of New South Wales; New Mexico State University nish@nmsu.edu
Vibrio fischeri is a bioluminescent marine bacterium found worldwide, an active member of the bacterioplankton community, and has been used as a model system to study their beneficial associations with sepiolid squids. V. fischeri also proliferates in a sessile, stable, community known as a biofilm, which is one alternative survival strategy of its life cycle. Although this survival strategy is adequate protection from abiotic factors, marine biofilms are still susceptible to grazing by bacteria-consuming protozoa. Subsequently, grazing pressure can be controlled by certain defense mechanisms that confer higher biofilm-anti-predator fitness. In the present work, we hypothesize that V. fischeri exhibit an anti-predator fitness behavior while forming biofilms. Different predators, representing commonly found species in aquatic communities were examined, including the flagellates Rhynchomonas nasuta and Neobodo designis (early-biofilm feeders), and the ciliate Tetrahymena pyriformis (late-biofilm grazer). V. fischeri biofilms included isolates from both seawater and squid hosts (Euprymna and Sepiola). Our results demonstrate inhibition of predation by biofilms, specifically isolates formed from seawater strains. Additionally, anti-protozoan behavior was observed to be higher in late biofilms, particularly from the ciliate T. pyriformis; however, inhibitory effects were found to be widespread among all isolates tested. These results provide an alternative explanation for the adaptive advantage and persistence of V. fischeri biofilms and provide an important contribution in the understanding of defensive mechanisms that exist in the out-of-host environment.
