Effect of chelating agents on plasmodium formation by the true slime mould, Didymium nigripes.

Abstract

SPORES of Didymium nigripes, a true slime mould, germinate to liberate myxamœbae which multiply by binary fission. After a period of exponential growth, the uninucleate myxamœbae fuse to form macroscopic, multinucleate veins of rhythmically flowing protoplasm called plasmodia. Following an indefinite period of growth, the plasmodia differentiate into spore-containing fruiting bodies. Kerr and Sussman1 grew D. nigripes in monoxenic culture with Aerobacter aerogenes on a dilute glucose–peptone–yeast extract agar medium buffered with phosphate at pH 6.2 (hereafter called GPY/5). All stages of the life-cycle were regularly reproduced in less than 7 days. When 0.25 per cent (w/v) brucine was added to the GPY/5, plasmodia did not appear. Instead, the myxamœbae remained indefinitely as such and could be sub-cultured as amœbae The myxamœbae quickly formed plasmodia when harvested from the GPY/5-brucine plates and washed by differential centrifugation.