A new antitumour substance, 7-oxabicyclo (2.2.1)-5-heptene-2,3-dicarboxylic anhydride.

7-Oxabicyclo(2.2.1)-5-heptene-2,3-dicarboxylic anhydride has been found to possess antitumour activity against Ehrlich ascites carcinoma cells.

Nilemycin, an intercalating agent for deoxyribonucleic acid.

1. Nilemycin (NM) is found to exert an inhibitory effect on the mouse tumor Sarcoma 180 near toxic doses but not with Leukemia 1210. 2.

Isolation of cairomycins A and C.

Cairomycin B in the fermentation broths of Streptomyces sp. strain AS-C-19 accompanied cairomycin A and cairomycin C. The cairomycins are peptides with potent activity against gram-positive bacteria.

The mechanism of action of polychlorosubtilin.

Polychlorosubtilin (PCS) inhibits the growth of Escherichia coli. The antibiotic affected neither respiration nor glycolysis while the synthesis of nucleic acids and proteins were feebly hindered. Formation of aminoacyl-tRNA, peptide bonds and translocation from A to P sites of ribosomes were insignificantly influenced by the drug.