| Résumé | The surface and internal structure of air-dried, freeze-dried, or critical-point-dried cells of Acetivibrio cellulolyticus were determined by negative staining, and by scanning and transmission electron microscopy. The cell wall has five layers, the outermost being the widest. This outermost layer is soft and amorphous, adsorbs cellulose microfibrils, and shows projections of tenuous appearance. Results of staining with heavy ions indicate that the outermost layer carries a net positive charge. The flagellum is a tubular, uniform extension of this outermost layer, about, 20 nm in diameter and approximately 6.4 μm long, with no visible internal details or basal body. The inner layers of the wall show no fine structure, other than differences in electron opacity. The cytoplasm is composed of a mixture of densely staining spheres and smaller globules in a background of fine particles. These particles are not completely destroyed by fixation with KMnO4, which indicates that they are low in ribonucleic acid. There is no evidence for membranes around or outside of any of these bodies. |
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