AN ELECTRON MICROSCOPE STUDY OF THE DISPOSITION AND FINE STRUCTURE OF MYCOBACTERIUM LEPRAEMURIUM IN MOUSE SPLEEN

Abstract

Ultrathin sections of methacrylate embedded mouse spleen infected with M. lepraemurium were examined in an electron microscope. The bacteria are separated from the host cytoplasm by a membrane which seems to be derived from the host. The space between the membrane and the bacterial cell wall is occupied by a finely granular material which may represent a bacterial product or capsule. The bacteria possess a 150 A thick cell wall and a 30 A thick cytoplasmic membrane. The bacterial cytoplasm contains low density nuclear areas which sometimes exhibit granular threads of denser material. Membrane-limited inclusions, apparently containing numerous spherical particles, are also found in the bacterial cytoplasm and are presumed to be mitochondrial equivalents.