TETRANACTIN, A NEW MITICIDAL ANTIBIOTIC

Abstract

In our screening for pesticidal antibiotics using Azuki-bean weevil as a test insect, a new antibiotic, tetranactin, was isolated as crystalline rhombic prisms from the filter cake of the fermented broth of Streptomyces aureus strain S-3466. Tetranactin shows significant insecticidal activity against Azuki-bean weevil by the topical application method but lucks the activity by the film contact method. The adults of carmine mite are highly sensitive to the antibiotic, since LC50 for the mite is 9 ppm bythe spray method. The antibiotic inhibits the growth of gram-positive bacteria and some phytopathogenic fungi in vitro at low concentrations. Acute toxicity of tetranactin is low ; mice tolerated an intraperitoneal administration of 300 mg/kg and an oral administration of 15, 000 mg/kg.