DIRECT ANTAGONISM IN MIXED BACTERIAL POPULATIONS

Abstract

Arrest of the growth of Bacillus subtilis by Aerobacter aerogenes was used in a study of the phenomenon of "direct antagonism". These organisms were grown in the same flask but separated by a cellophane barrier. It was found that inhibition of growth is due to removal of O2 and oxidized substrates from the medium. B. subtilis does not grow unless the Eh of the medium is in the vicinity of +0.120 volts. The role of oxidation-reduction systems in the growth of mixed bacterial populations is emphasized.