Aluminium, chromium and manganese detoxification mechanisms in Pseudomonas syringae: an X-ray fluorescence study.

Pseudomonas syringae cultured in a defined citrate medium supplemented with 1 mM aluminium, chromium and manganese, respectively, appeared to elicit disparate biochemical responses. At the stationary phase of growth aluminium was predominantly present as an insoluble residue. Although virtually none of this metallic element was detected in the supernatant, the bacterial cells appeared to contain some aluminium. Following the initial uptake of chromium the microbe secreted the metal in the supernatant. Only a small fraction of the chromium was localised in the bacterial cells; 91% manganese was biotransformed into an insoluble pellet. No citrate was detected in the exocellular fluid at cessation of cellular growth.