FIG. 6.

(A) Proposed model for the interaction of phospholipases with eut genes to provide alternative C and N sources to intracellular L. monocytogenes. Phosphatidylethanolamine derived from phospholipids of host cell membranes could be broken down by the listerial phospholipase PlcB (which is highly active intracellularly) into glycerol and ethanolamine which then provides additional C or N sources by the action of the EutBC (ethanolamine ammonia-lyase). Acetyl-CoA, acetyl coenzyme A. (B) Proposed model for the regulation and fine tuning of nitrogen metabolism by L. monocytogenes for intracellular proliferation. TCA-cycle, tricarboxylic acid cycle.