ON THE MODE OF ACTION OF ASK-753, A NEW IRON-CONTAINING ANTIBIOTIC

Abstract

The effect of antibiotic ASK-753 on cell morphology DNA, RNA and protein syntheses in E. coli, B. subtilis and B. mycoides was studied. In the presence of the antibiotic, gram-positive bacteria formed long filaments, while gram-negative bacteria formed short filaments. It was found that this antibiotic causes inhibition of DNA, RNA and protein syntheses. This inhibition was reversible in E. coli, while it is irreversible in B. subtilis and B. mycoides. By programming the addition and removal of the antibiotic, DNA and RNA syntheses can be made to proceed instepwise increments corresponding to doublings of the DNA. ASK-753 causes the release of 260 mμ absorbing materials from the ASK-753 sensitive strains of B. subtilis. It also lyses protoplasts of B. subtilis but not spheroplasts of E. coli. On the basis of this study, it was concluded that this antibiotic acts primarily on the cellular membrane and consequently leakage of intracellular material occurs.