Disruptive effects of tris and sodium lauroyl sarcosinate on the outer membrane of Pseudomonas cepacia shown by fluorescent probes.

The disruptive effects of Tris buffer and sodium lauroyl sarcosinate (Sarkosyl) on the outer membrane (OM) of Pseudomonas cepacia were investigated with several fluorescent probes. Tris increased the permeability of the OM to 6-anilino-l-naphthalenesulphonic acid and 2-p-toluidinylnaphthalene-6-sulphonate. The degree of damage to the OM was enhanced when the pH was decreased 3-(N-morpholino)propanesulphonic acid buffer had a small but significant effect at acid pH, while citrate/phosphate buffer showed insignificant effects. Sarkosyl released 3,3'-dipentyloxacarbocyanine iodide (CC5) from CC5-labelled OM or whole cells and altered OM fluidity as studied by fluorescence polarization.