Isolation and Preliminary Characterization of a Bacterial Mutant Possessing Increased Barophilicity
Tetsushi KOMATSU and Douglas H. BARTLETT*
Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA92093-0202, USA
Photobacterium profundum strain SS9 is a moderately barophilic (high pressure adapted) deep-sea isolate. In order to further study mechanisms of pressure adaptation in strain SS9 we have selected for spontaneous mutants which possess enhanced growth ability at high pressure. Selection near the upper pressure limit of strain SS9 at 60 Megapascal (MPa) in solid medium resulted in the-isolation of one such mutant designated TK1. Strain TK1 grew very slowly on solid medium at atmospheric pressure. During incubation at atmospheric pressure in liquid medium TK1 cells formed multicellular aggregates, suggesting that this mutant possesses some type of cell surface alteration. In liquid culture at 27 MPa strain SS9 and TK1 grew similarly, but during cell growth near the pressure maximum of strain SS9, strain TK1 displayed a shorter lag period. Future experimental work will be directed towards the selection, isolation and characterization of addition high pressure growth mutants and their genetic and biochemical characterization.
