Gonococcal Bacteriocins. Inhibition of Gonococci by Lysophosphatides and Free Fatty Acids of N. Gonorrhoeae and by Inhibitory Substances from other Bacteria; Analysis of N. Gonorrhoeae Phospholipase Activity.

Analysis of previous data suggested the gonococcal inhibitory substances produced by N. meningitidis and N. gonorrhoeae were bacteriocin- like materials, possibly the protein complement of the lipopolysaccharide of the Neisseria cell wall. The inhibitors can be extracted quantitatively from meningococcal or gonococcal cells using chloroform. The inhibitors are heat stable and are not degraded by proteolytic enzymes. The inhibitors are not proteins, but appear to be lysophosphatides and possibly free fatty acids. Preparation of these substances on silica gel thin layer plates gave solutions which killed gonococci in liquid medium, inhibited growth on solid medium, and inhibited uptake of adenine3H. Analysis of phospholipid composition of lysophilized cells showed phosphatidylethanolamine, 69-75 phosphatidylglycerol, 16 cardiolipin, 2-3 and lysoposphatidylethanolamine LPE, 6-11. However, the amount of LPE was only 1 when freshly grown cells in growth medium were extracted. Phospholipase A activity was associated with the cell membranes.