ELECTRON MICROSCOPICAL AND SEROLOGICAL CHARACTERISTICS ASSOCIATED WITH COLONY TYPE IN <i>MORAXELLA NONLIQUEFACIENS</i>

Abstract

Pairs of the spreading‐corroding (SC) colonies on the one hand and normal smooth (N) colonies on the other of Moraxella nonliquefaciens were studied. Electron microscopy revealed that SC cultures are distinguished by the occurrence of numerous fimbriae ( s. pili ) of 60–70 Å diameter. The usual SC fimbriae are morphologically different from another filament type found occasionally around cells from N colonies and detected very infrequently in SC cultures. Serologically, no easily observed difference was found between SC and N lines of the same origin, but the former was distincly prone to incomplete agglutination in anti‐sera against the SC type absorbed by cells of the other type. This could be ascribed to the fimbriae which were probably present in unequal quantities among the cells of SC populations. In both colony variants, a heat labile envelope antigen corresponding to the B‐type was discovered. The possible roles of the fimbriae are briefly discussed.