Effects of luxCDABEG induction in Vibrio fischeri : enhancement of symbiotic colonization and conditional attenuation of
- PDF / 623,648 Bytes
- 15 Pages / 595 x 791 pts Page_size
- 44 Downloads / 160 Views
ORIGINAL PAPER
EVects of luxCDABEG induction in Vibrio Wscheri: enhancement of symbiotic colonization and conditional attenuation of growth in culture JeVrey L. Bose · Charles S. Rosenberg · Eric V. Stabb
Received: 14 November 2007 / Revised: 23 April 2008 / Accepted: 8 May 2008 / Published online: 3 June 2008 © Springer-Verlag 2008
Abstract Production of bioluminescence theoretically represents a cost, energetic or otherwise, that could slow Vibrio Wscheri growth; however, bioluminescence is also thought to enable full symbiotic colonization of the Euprymna scolopes light organ by V. Wscheri. Previous tests of these models have proven inconclusive, partly because they compared nonisogenic strains, or undeWned and/or pleiotropic mutants. To test the inXuence of the bioluminescence-producing lux operon on growth and symbiotic competence, we generated dark luxCDABEG mutants in strains MJ1 and ES114 without disrupting the luxR-luxI regulatory circuit. The MJ1 luxCDABEG mutant outcompeted its visibly luminescent parent »26% per generation in a carbon-limited chemostat. Similarly, induction of luminescence in the otherwise dim ES114 strain slowed growth relative to luxCDABEG mutants. Some culture conditions yielded no detectable eVect of luminescence on growth, indicating that luminescence is not always growth limiting; however, luminescence was never found to confer an advantage in culture. In contrast to this conditional disadvantage of lux expression, ES114 achieved »fourfold higher populations than its luxCDABEG mutant in the light organ of E. scolopes. These results demonstrate that induction of luxCDABEG can slow V. Wscheri growth under certain culture conditions and is a positive symbiotic colonization factor.
Communicated by Andreas Brune. J. L. Bose · C. S. Rosenberg · E. V. Stabb (&) Department of Microbiology, University of Georgia, 828 Biological Sciences, Athens, GA 30602, USA e-mail: [email protected]
Keywords Photobacterium · Aliivibrio · Autoinduction · Competition · Evolution
Introduction Vibrio Wscheri serves as a model system for studies of both bioluminescence and symbiotic bacteria–animal interactions. This bacterium’s bioluminescence has been examined since the late nineteenth century (Harvey 1952), whereas studies of V. Wscheri’s symbiotic interactions have gained recent momentum from the ability to reconstitute its symbiosis with the Hawaiian bobtail squid Euprymna scolopes in the laboratory (Wei and Young 1989; Stabb 2006). V. Wscheri’s bioluminescence and symbiotic interactions are intimately interrelated. For example, the most obvious symbiotic role of V. Wscheri is to generate bioluminescence in specialized light emitting organs of hosts, and bioluminescence is induced upon colonization—an eVect that is particularly pronounced in symbionts of E. scolopes (Boettcher and Ruby 1990, 1995). Most interestingly, Visick et al. (2000) reported that bioluminescence acts as a colonization factor, and that without it V. Wscheri does not fully colonize E. scolopes. Unfortunately, the parent strain u
Data Loading...
