[Protein and peptide factors from Bacillus sp.739 inhibit the growth of phytopathogenic fungi].

Thermolabile peptides inhibiting the growth of Helminthosporium sativum, a facultative phytopathogen, have been isolated from the low-molecular-weight fraction of extracellular metabolites of the strain Bacillus sp. 739. Paper chromatography of the fraction, followed by bioautography, revealed the presence of three components exhibiting antifungal activity. These components were separated by gel chromatography on Toyopearl HW-40. SDS-PAGE (the Laemmli procedure) demonstrated that only one component was a protein (MW, approximately 14 kDa). The other two substances were polypeptides with molecular weights less than 6 kDa each. The protein factor inhibited the growth of H. sativum with a minimum effective concentration of 0.1 to 0.2 mg/ml.