Phospholipid composition and phospholipase A activity of Neisseria gonorrhoeae

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Abstract
Exponential-phase cells of N. gonorrhoeae 2686 were examined for phospholipid composition and for membrane-associated phospholipase A [EC 3.1.1.4] activity. When cells were harvested by centrifugation, washed and lyophilized before extraction, .times. 74% of the total phospholipid was phosphatidylethanolamine, 18% was phosphatidylglycerol, 2% was cardiolipin and 10% was lysophosphatidylethanolamine. When cells still suspended in growth medium were extracted, the amount of lysophosphatidylethanolamine decreased to .apprx. 1%. This suggests that a gonococcal phospholipase A may be activated during centrifugation and/or lyophilization of cells preceding extraction. Phospholipase A activity associated with cell membranes was assayed by measuring the conversion of tritiated phosphatidylethanolamine to lysophosphatidylethanolamine. Optimal activity was demonstrated in 10% methanol at pH 8.0-8.5, in the presence of Ca2+. The activity was detergent sensitive and thermolabile. Comparisons of gonococcal colony types 1 and 4 showed no significant differences between the 2 types with respect to phospholipid content or phospholipase A activity.

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