Abstract
Persistence and survival under various environmental stresses has been attributed to the capacity of most bacteria to form biofilms. In aquatic environments, the symbiotic bacterium Vibrio fischeri survives variable abiotic conditions during its freeβliving stage that dictates its ability to colonize the squid host. In the present study, the influence of different abiotic factors such as salt concentration, temperature, static/dynamic conditions, and carbon source availability were tested to determine whether biofilm formation occurred in 26 symbiotic and freeβliving V. fischeri strains. Statistical analysis indicate that most strains examined were strong biofilm producers under salinity concentrations that ranged between 1β5%, mesophilic temperatures (25β30 Β°C) and static conditions. Moreover, freeβliving strains are generally better biofilm formers than the symbiotically competent ones. Geographical location (strain origin) also correlated with biofilm formation. These findings provide evidence that abiotic growth conditions are important for determining whether mutualistic V. fischeri have the capacity to produce complex biofilms, allowing for increased competency and specificity during symbiosis. (Β© 2011 WILEYβVCH Verlag GmbH & Co. KGaA, Weinheim)