Meeting Abstract

P3.4  Jan. 6  Salinity optical density profiles of bioluminescent Vibrio fischeri from free-living and symbiotic environments SOTO, W.*; GUTIERREZ, J.; NISHIGUCHI, M.K.; New Mexico State Univ.; New Mexico State Univ.; New Mexico State Univ. wisoto@nmsu.edu

Vibrio fischeri is a bioluminescent bacterial symbiont of sepiolid squids (Cephalopoda: Sepiolidae) and monocentrid fishes (Actinopterygii: Monocentridae), which primarily reside in the Indo-West Pacific Ocean. Mutualistic bacteria inhabit a morphological structure referred to as a light organ, where symbionts benefit the host animals by enabling them to utilize the bacterial bioluminescence in a cryptic behavior termed counterillumination. In an effort to provide initial insight on the role salinity may have on bacterial colonization between squid hosts from different habitats, turbidity (OD₆₀₀) measurements were measured of V. fischeri strains from numerous free-living and host environments after incubation in nutrient-rich liquid media, ranging in NaCl concentration from 0% to 9.0%. Differences were observed in the sodium chloride concentration where maximal growth occurred for most V. fischeri strains. Additionally, upper and lower limits of growth varied for a multitude of bacterial isolates. In some instances, sudden and sharp demarcations existed where a particular strain grew significantly and where it did not grow at all, indicating gradual zones of decreasing growth are not always present with slight changes in salinity. Hence, subtle salinity changes in the marine environment could dramatically influence squid host and V. fischeri symbiotic relationships.