ELECTRON MICROSCOPICAL AND CULTURAL FEATURES OF <i>NEISSERIA MENINGITIDIS</i> COMPETENCE VARIANTS

Abstract

Competent and incompetent variants of five strains of Neisseria meningitidis were examined by negative stain electron microscopy with the aim of detecting a possible correlation between the competent state in DNA mediated transformation and the presence of special surface structures. As previously reported for species of Moraxella , a correlation between the occurrence of fimbriae at or near the cells and a high level of competence was found. Various conditions of cultivation were investigated to see if small, previously unnoticed, differences in type of growth could exist between the competent and incompetent variants. No difference could be detected in colony morphology on solid medium. However, in statically incubated broth the competent variants were distinguished by forming a surface pellicle after one to two days of growth.