The effect of ethylenediaminetetraacetate and its calcium chelate on the rate of swelling of a strain of Pseudomonas aeruginosa in salt solutions

Abstract

BERNHEIM, F. 1972. The effect of ethylenediaminetraacetate and its calciun~ chelate on the rateofswelling of a strain of Pseridomonas aerriginosa in salt solutions. Can. J. Microbiol. 18: 1643-1646. When washed suspensions of Pseudornonas aerrcginosa are placed in salt solutions, the cells shrink rapidly and then swell more slowly as salt and water enter them. The rate of swelling is increased by EDTA and its calcium chelate. The effect of EDTA is antagonized by diamines; the effect of the calcium chelate by carboxylic acids. The relative effects of EDTA and the calcium chelate differ in different salts which suggests different sites of action. The evidence indicates that EDTA does not act by chelating calcium or magnesium in the membrane of these cells but that its two nitrogen atoms combine by electrostatic forces with anionic sites, and the chelate, in which the nitrogen atoms are bound to calcium, combines by the same forces to cationic sites. Barium, strontium, and magnesium chelates are inactive.