Column chromatography and cell culture assay of Pseudomonas aeruginosa toxin Z preparations.

Toxic material produced by Pseudomonas aeruginosa in cell culture was concentrated and partially purified. This toxic material, designated toxin Z, was produced during the growth of strain PA Z or PA 103 in HEp-2 monolayer cultures using Eagle minimal essential medium with 10% serum. Toxin Z, concentrated fourfold by Lyphogel or ultrafiltration, was used to produce antiserum in rabbits and also was fractionated by column chromatography. Twentyfold purification of toxin Z was obtained on a Sephadex G-200 column. Toxic column fractions were confirmed to have toxin Z by neutralization with specific antiserum. During concentration, purification, and neutralization procedures, the toxin was assayed exclusively by the cytopathic effect it produced in cell culture.

Volutin granules in Zoogloea ramigera.

Zoogloea ramigera, a gram-negative bacterium found in activated sludge, formed volutin granules when excess orthophosphate was added to a phosphate-starved culture. These volutin granules were stainable by hydrogen sulfide after lead acetate treatment and extractable by N-perchloric acid but were not adsorbed by activated charcoal. They appeared to consist of inorganic polyphosphate. Optimum granule formation in the arginine broth required 10 g of glucose, 3 mg of phosphate, and 1 to 20 mg of magnesium per liter of medium. At an Mg(2+) concentration of 1 mg/liter, very large granules appeared which often appeared to fill the cell. An excess of glucose, orthophosphate, or magnesium reduced granule formation. In the absence of sulfate, moderate granulation occurred in arginine broth before the addition of excess orthophosphate; granulation did not increase after the addition of phosphate.