24th Annual Student Research Conference
The Unusual Suspects: A Characterization of Four Conditionally-Lethal Vibrio fischeri Mutants
John H. Kimbrough
Dr. Eric V. Stabb (University of Georgia) and Dr. Peter Goldman, Faculty Mentors
The symbiosis between the bacterium Vibrio fischeri and the squid Euprymna scolopes is a powerful model for biological mutualisms and host-microbe interactions. We utilized a hyperactive mini-Tn5 transposon to generate mutations in genes essential for growth in V. fischeri. Three transposon mutants were examined with insertions in the genes alr, gspE, and ftsA. Alr, a D-alanine racemase, generates D-alanine used in peptidoglycan (PG) biosynthesis, and mutants require D-alanine for growth. GspE is an ATP hydrolyzing component of the type II secretion system, and mutants require additional magnesium for growth. FtsA, a cell division associated protein, regains partial function with supplemental magnesium. Motility, growth rate, and bioluminescence phenotypes of these mutants were characterized, features that contribute to a successful symbiosis. We present phenotypic data for several conditionally lethal mutants, which will be important determining the environment of the light organ and the physiological requirements of the symbiont during colonization.
Keywords: Vibrio fischeri, symbiosis, mutualism, bacterial genetics, host-microbe interaction, type II secretion, peptidoglycan , transposon mutagenesis
Topic(s):Biology
Presentation Type: Poster
Session: 3-5
Location: Georgian Room - SUB
Time: 4:30