Flagella, gas vacuoles and cell-wall structure in Halobacterium halobium; an electron microscope

SUMMARY: A droplet of a suspension of Halobacterium halobium in a concentrated brine when left to dry on a collodion-covered grid yields a useful preparation for electron microscopy. Two strains, one red and one pink, were examined. Both strains have polar tufts of flagella. The cell wall contains a single layer of hexagonally arranged globular particles. Halobacterium halobium has these characteristics in common with Spirillum spp., but unlike the true Spirillum spp. it is rod-shaped. Electron microscopical examination showed that the gas vacuoles observed by Petter (1931, 1932) to be a feature of pink strains of H. halobium actually were smaller but much more numerous than the optical microscope revealed. Stereo-pictures show that these vacuoles did not collapse upon desiccation of the bacteria. Red discoloration of salted fish can be caused by at least three distinct species of bacteria. In most cases a rod-shaped bacterium has been isolated from the substrate. Bacillus halobius ruber is the name Klebahn (1919) gave to a red rod-shaped halophilic bacterium. Petter (1931) changed the name to Bacterium halobium because it does not form spores. According to her, Pseudo