On a fungistatic, substance produced in culture filtrates of Gloeosporium Olivarum on media containing 2, 4-D

Abstract

1. The present report deals with the production as well as the isolation of a fungistatic substance, which was obtained from the culture filtrates of Gloeosporium Olivarum Alm. on media containing 2, 4-D Na salt.
2. When the acidified filtrates (pH 2.5) were shaked with ether and then with 4% NaOH, a brown oil was obtained in partly purified form after evaporation of ether. The growth of causal fungus was completely inhibited at the dilution of 1:5, 000 by this substance, of which activity was stable 130°C for at least 3 hours and not inactivated at a pH range between 4.0 and 11.2.
3. The inhibitory activity of 2, 4-D does not depend on its direct effect against the pathogen but mainly on this fungistatic product induced by addition of 2, 4-D.
4. The material toxic to the pathogen was produced most abundantly at 0.04% of 2, 4-D. On media supplied with 2, 4-D the fungal growth ceased within about twelve days of culture in spite of nonexhaustion of nutrients, however the production of the toxic material yet continued during the successive culture.
5. The yield was also maximum on a Richards's medium, of which components sodium nitrate was substituted by ammonium tartarate. The cause would probably be attributed to the higher absorption of 2, 4-D molecules by mycelia owing to the lower level of pH during culture.