The Effect of Adding Clays to Mixed Cultures of Streptomyces albidoflavus and Fusarium culmorum

Abstract

SUMMARY: An antibiotic present in culture filtrates of Streptomyces albidoflavus was inactivated by clays and by suspensions and extracts of soils. When this actino-mycete was grown with Fusarium culmorum in a sand+bentonite mixture moistened with nutrient solution, it did not antagonize the fungus by antibiotic secretions. However, suppression of fungus growth was observed even in the presence of bentonite particularly when glucose was present in abundance; this effect was attributed to competition between the organisms for limiting nutrients. The actinomycete also lysed the contents of the fungus mycelium in sand culture but not when bentonite was added. The lytic agent appeared to differ from the antibiotic. Neither antibiotic action nor direct (lytic) attack on the fungus was demonstrated in sterilized soil.