Particulate Fractions of Neisseria gonorrhoeae

Abstract Passage of gonococcal cells through a Ribi cell fractionator produced a mixture of protoplasm and cell particulates, the latter being separable in sucrose solutions. Separation of these particulates resulted in the detection of objects identified as cell walls and “plasts.” The latter objects had an average diameter of 1.00 ± 0.05 μm and consisted of spatially oriented granules surrounded by a membrane-like structure only. Cell wall structures were not observed with these plasts. Plasts were morphologically stable in distilled water and at low pH values. Although 50% more pressure was required to rupture plasts than whole cells, plast morphology was destroyed by organic solvents. Whole cell and plast morphology was examined by electron and phase microscopy, and certain correlations were made between structure and morphological stability. Cell wall antiserum reactivities were quantitatively different for plasts and cell walls. Serological reactivities of plasts were separable by sonic oscillation and differential centrifugation of the sonically treated material.