Inhibition of Halobacterium cutirubrum Lipid Biosynthesis by Bacitracin

Halobacterium cutirubrum, an extremely halophilic bacterium, lacks a normal peptidoglycan cell wall. Nevertheless, bacitracin, a known inhibitor of peptidoglycan synthesis, has been shown to completely suppress the growth of this organism (Mescher & Strominger, 1975) In an attempt to clarify this observation, the effect of bacitracin on DNA, RNA, protein and lipid biosynthesis in H. cutirubrum was monitored. Lipid carbohydrate and lipid phosphate were the most affected. These observations were confirmed by uptake studies of [14glycerol into the membrane lipids. The possibility that bacitracin acts against H. cutirubrum through inhibition of dephosphorylation of the isoprenoid pyrophosphate precursors of this organism's diether lipids is discussed.