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 bymeasurement of optical density, the increase in viable cells was suppressed to a great extent. Such effects of tunicamycin are observed without inhibition of protein, DNAand RNAsynthesis in Bacillus subtilis W23 cells. RNAand DNAdegradation 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 acidsolubilization of the cellular macromolecules labeled with radioactive amino acids or glucosamine.