Effect of Tunicamycin on Microorganisms: Morphological Changes and Degradation of Rna and Dna Induced by Tunicamycin

The treatment of gram-positive bacteria and yeasts with tunicamycin induces morphological changes such as elongation, conversion from rod-form to cocci-form and enlargement of microbial cells. Even when bacteria grew normally or to a somewhat lesser extent than controls as determined by measurement of optical density, the increase in viable cells was suppressed to a great extent. Such effects of tunicamycin are observed without inhibition of protein, DNA and RNA synthesis in Bacillus subtilis W 23 cells. RNA and DNA degradation occurred subsequent to the morphological changes of B. subtilis cells, and the former degraded to a larger extent than the latter. No difference was detected between control and tunicamycin-treated cells in acid-solubilization of the cellular macromolecules labeled with radioactive amino acids or glucosamine.