Bacterial motility is considered one of the most pressure sensitive cellular processes, where increased pressure acts as an inhibitor of new flagella formation and arrests the functioning of assembled filaments. Maintaining motility under high hydrostatic pressure and the physiological mechanisms required to produce a functional filament remain one of the challenges deep-sea prokaryotes face. Genomic comparisons between the flagellar systems of the model deep-sea bacterium Photobacterium profundum strain SS9 and pressure-sensitive P. profundum strain 3TCK, and subsequent motility assays and genetic manipulations, have provided insight into the physiology of flagellar motility under deep-sea pressure conditions.
Our recent work, in collaboration with Dr. Rudi Vogel at the Technical University of Munich, involved using a high-pressure microscope system to directly measure swimming velocity as a function of increased pressure. Currently, we are interested in using comparative genomics to dissect the genetic features enabling piezophiles to maintain motility at high hydrostatic pressure.