Walsby's square bacterium: fine structure of an orthogonal procaryote.
The "square" bacterium, first described by Walsby from brine collected at the Red Sea shore [A. E. Walsby, Nature (London) 283:69-71, 1980] was examined by electron microscopy. The cells appeared as flat rectangular boxes in scanning electron micrographs. In sections and freeze-fracture preparation, the edges looked more rounded. The thickness apparently remains constant as the cells grow and divide. Their sides were a few micrometers long, but the cells were only 0.25 micrometers thick. They showed typical procaryote structure, with a regular cell wall and a gas vacuole fine structure similar to that of other halophilic procaryotes. The inner fracture faces of the cell membrane showed a much denser population of intramembrane particles than the outer fracture faces, but no patches of purple membrane, despite the presence of bacteriorhodospin-like pigment in the cell suspension. Morphologically identical cells have been found in brine from Baja California, Mexico.
D001419:Bacteria / Q000032:analysis / Q000648:ultrastructure*; D001436:Bacteriorhodopsins / Q000032:analysis; D002473:Cell Wall / Q000648:ultrastructure; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D005614:Freeze Fracturing; D008855:Microscopy, Electron, Scanning; D012965:Sodium Chloride; D014617:Vacuoles / Q000648:ultrastructure; D014871:Water Microbiology
D012965:Sodium Chloride; D001436:Bacteriorhodopsins