Growth Inhibition Among Strains of Neisseria gonorrhoeae due to Production of Inhibitory Free Fatty Acids and Lysophosphatidylethanolamine: Absence of Bacteriocins

Abstract

Each of 50 tested strains of Neisseria gonorrhoeae produced growth-inhibitory substances that were active against most strains of gonococci or meningococci, but not against species other than the Neisseria. There were quantitative differences among different strains in production of the inhibitor and sensitivity to it, but not of sufficient magnitude to permit routine strain typing. The inhibitor was associated with the cell pellet (crude cell envelope) and was not inducible with mitomycin C. Inhibitory activity was thermostable and resisted alkali and proteolytic enzymes. The inhibitor was quantitatively recovered from whole cells by chloroform-methanol extraction. Separation of total gonococcal lipids by silica gel chromatography revealed inhibitory activity in both the free fatty acid and the phospholipid fractions. The major phospholipid, phosphatidylethanolamine, had no inhibitory activity, but monoacyl phosphatidylethanolamine, a minor phospholipid, was quite inhibitory. It is likely that the “bacteriocin” of N. gonorrhoeae strains results from the degradation of phosphatidylethanolamine to inhibitory long-chain free fatty acids and monoacyl phosphatidylethanolamine.

EXPRESSION OF BACTERIOCIN‐LIKE ACTIVITY IN BATCH CULTURES OF NEISSERIA MENINGITIDIS AND CONSEQUENCES FOR GENETIC RECOMBINATION

“…The first type which was observed in most strains examined inhibited all meningococcal strains tested, including the donor strain. This activity seemed to be similar to the non-specific growth inhibition observed among most strains of Neisseria gonorrhoeae (9,10). The second type was bactericidal and showed high strain specificity.…”

The serological classification of Neisseria gonorrhoeae. I. Isolation of the outer membrane complex responsible for serotypic specificity.

“…These observations were confirmed by Danielsson (21) who also noted that N. sicca, Neisseria tiara, and Neisseria flavescens reacted with antigonococcal globulin. Recent investigations, most notably those of Carifo and Catlin (22) and LaScolea and Young (23), have dwelt upon the feasibility ofauxotyping, while others (24,25), though unsuccessful, have probed the possibility of bacteriocins as potential candidates for gonococcal serotyping. The isolation of pili as a discrete protein antigen of the virulent colonial types, T, and T2, by Buchanan et al (26) prompted the analysis of pill as having serotypic specificity.…”

Phospholipid metabolism inNeisseria gonorrhoeae: Phospholipid hydrolysis in nongrowing cells

“…It is significant that products of phospholipid hydrolysis remain cell-associated under nongrowth conditions and are not selectively released into the buffer. This is in contrast to reports that in gonococci, FFA accumulate in the medium during growth (1,27). The activity of phospholipase A in growing cells will be considered in a subsequent publication.…”

“…Gonococci release free fatty acids (FFA) and lysophosphatidylethanolamine (LPE) into the medium during growth (1). The release of these products suggests that phosphatidylethanolamine (PE), a major cell envelope component of Neisseria gonorrhoeae, is hydrolysed by phospholipase(s) (1).…”

“…Gonococci release free fatty acids (FFA) and lysophosphatidylethanolamine (LPE) into the medium during growth (1). The release of these products suggests that phosphatidylethanolamine (PE), a major cell envelope component of Neisseria gonorrhoeae, is hydrolysed by phospholipase(s) (1). Further evidence for hydrolysis of PE in gonococci has been shown by the cellular accumulation of LPE in stationary phase cultures (2), and in cells which were suspended in buffer and lyophilized (3).…”