The effects of hydrostatic pressure on bacterial attachment

Abstract

The effects of elevated hydrostatic pressure on the ability of a marine bacterium to attach to solid surfaces were examined. Cell viability of Pseudomonas perfectomarina appeared to be only moderately affected by pressures up to 608 Mbar (= 600 atm). However, pressures above 405 Mbar resulted in a dramatic reduction in primary film formation compared to control cultures maintained at 1 Mbar. A pressure of 600 atm almost completely inhibited the ability of this organism to attach to the surface. Decreased ability to attach could not be accounted for solely by pressure‐induced inhibition of metabolic processes, since the percentage of cells which did attach and subsequently develop into microcolonies under pressure equalled that of 1 Mbar controls. Thus, pressure appears to have a significant effect on the initial stages of attachment, and not solely on cell metabolism. The possibility that microbial attachment to surfaces may be a survival mechanism allowing attached cells to remain metabolically active under pressure is discussed.