Temperature-dependent protein and lipopolysaccharide expression in clinical Aeromonas isolates

Clinical isolates of Aeromonas were grown at eight different temperatures from 10 degrees C to 40 degrees C. Whole cell lysates were examined by SDS-PAGE and major temperature-dependent changes to both protein and lipopolysaccharide (LPS) profiles were identified. Cells grown at the higher temperatures (37 degrees C and 40 degrees C) produced abundantly a protein of c. 60 kDa which was not detected at the lower temperatures. Temperature-dependent expressions of other proteins were also noted but these were more variable among the isolates. An effect of temperature on expression of lipopolysaccharides was also noted in that some strains produced significantly less O-polysaccharides at the higher temperatures. After fractionation of cells, major differences in the expression of cell envelope and outer-membrane proteins between cells grown at low and high temperatures were noted although no unifying patterns could be discerned. Such growth temperature-induced changes in the cell envelope constituents have not been described previously for Aeromonas isolates from man.