Studies on the gonococcus

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Abstract
I. Microchemical analyses were carried out on 6 strains of N. gonorrhoeae[long dash]4 recently isolated strains and 2 that had been under cultivation for 14 mos. and 32 yrs., respectively[long dash]grown in Douglas''s broth. Data are presented on 19 components of the cell. Carbohydrate constituted 5-9% of the wt. of the dried cell, lipid 10-14%, and nucleo-protein 60-65%. Volatile and non-volatile matter constituted an additional 13-18%. Comparative analyses on cultures grown for 3, 6, and 10 days showed that P-containing constituents, chiefly nucleic acid and phospholipid, are reduced to 1/2 their maximal value between the 3d and the 6th day. No such change was noted in the nitrogenous components, notably protein, certain amino acids, nitrogenous lipid, and amino sugar. Two nucleoprotein fractions were isolated, analyzed, and a number of their properties described. Of chief importance was the characterization of a relatively insoluble liponucleoprotein containing approx. 25% bound lipid and a minor lipid-free soluble nucleopro- tein which constituted the major part of the gonococcal cell. The lipid which was recovered was highly complex. It has been separated into several crystalline and non-crystalline substances, certain of which have been identified as a lecithin, a cephalin, and a sphingomyelin. No lipid constituent characteristic of the gonococcus was obtained. It was not possible to demonstrate by chemical methods of analysis or of isolation the presence of a type-specific poly-saccharide in the gonococcal cell grown in Douglas''s broth. The chemical findings are discussed in relation to the constituents of other bacterial spp.[long dash]II. A protein-like fraction, possessing "toxic" and antigenic properties, was separated from broth cultures of N. gonorrhoeae after removal of the cells by centrifugation. The fraction appeared to be a protein degradation product derived from the nucleoprotein of the cells. This conclusion is based upon its destruction by proteolytic enzymes, by reversible loss of complement-fixing activity after treatment with protein denaturants, by its peculiar immunologic behavior in specific antisera and, finally, by chem. analyses. The purified fraction fixed complement in the presence of sera from rabbits immunized with N. gonorrhoeae and of sera from patients with gonococcal infection. The toxicity of the fraction for laboratory animals was greater than that of nucleoprotein of the cells. The MLD100 of several prepns. varied from 0.1 to 0.7 mg. for white mice weighing 20-22 gm. The major component of the purified fraction consisted of molecules with similar electrophoretic behavior and antigenic activity. The minor component was rich in carbohydrate and non-antigenic.[long dash]III. A measure of the immunologic interrelationships of Neisseria has been obtained by use of a modified quantitative agglutinative technique, based on those of Heidelberg and Kabat. The adaptation of these methods, shown to be necessary in the case of N. gonorrhoeae, consisted in carrying out the reaction at pH 5.9. At this pH the solubility of certain antigenic constituents of the gonococcal cell was minimized, and the maximal amt. of aggluti-nin was recovered. A study of 9 strains of N. g. isolated from various types of gonococcal infection and maintained under artificial cultivation for from 1 mo. to 34 yrs. failed to show any evidence of distinct types or groups. There was a closer immunologic relationship between certain strains of N. intracellularis and N. gonorrhoeae than among certain strains of the latter sp.