Growth-physiological changes in Escherichia coli and other bacteria during division inhibition by 5-diazouracil.

Diazouracil (DZU) was shown to increase the mean cell volume of several bacterial species. The filaments which it induced with Escherichia coli B and Lactobacillus casei were examined in section by electron microscopy. In addition to the inhibition of division of E. coli by DZU, its effects were studied on mass increase, viability, and deoxyribonucleic acid, ribonucleic acid, and protein synthesis. The dependence of cell age on the division-inhibitory effect of DZU was examined in synchronous cultures. The division-inhibitory effect was not reversed by pantoyllactone, an antagonist of ultraviolet filamentation, or by l-tyrosine, which had been reported to antagonize DZU activity.