A square bacterium

  title={A square bacterium},
  author={A. E. Walsby},
I have come across a bacterium which has the form of a thin square sheet. In most bacteria such a shape would be precluded by the osmotically-generated internal hydrostatic pressure but this organism, found in a saturated brine pool, has little or no cell turgor pressure. Its shape is probably determined by the pattern in which the cell envelope particles assemble. These square bacteria are so thin and transparent and are so unlike any bacteria previously described that I would have overlooked… Expand
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, was examined by electron microscopy and showed typical procaryote structure, with a regular cell wall and a gas vacuole fine structure similar to that of other halophilic procaryotes. Expand
Gas vesicles
The gas vesicle is a hollow structure made of protein. It usually has the form of a cylindrical tube closed by conical end caps. Gas vesicles occur in five phyla of the Bacteria and two groups of theExpand
Ultrastructure of square bacteria from a brine pool in Southern Sinai
Optical diffraction confirms the existence of both hexagonal and tetragonal arrangements of the cell wall subunits and also of different lattice constants and suggests a mixed population of bacteria. Expand
Archaea with square cells.
  • A. Walsby
  • Biology, Medicine
  • Trends in microbiology
  • 2005
Genetic analysis shows that the squares, discovered 25 years ago on the Sinai Peninsula, are archaea rather than bacteria, and Paradoxically, the square archaea are the dominant microorganisms in some hypersaline environments and might be globally important. Expand
Crystalline Bacterial Cell Surface Layers
Thecrystalline arrays of proteinaceous subunits forming surface layers reveal a broad-application potential in biotechnology, vaccine development and molecular nanotechnology. Expand
The Selective Value of Bacterial Shape
  • K. Young
  • Biology, Medicine
  • Microbiology and Molecular Biology Reviews
  • 2006
The aim of this review is to spell out the physical, environmental, and biological forces that favor different bacterial morphologies and which, therefore, contribute to natural selection. Expand
Big bacteria.
The most striking examples of competitive advantage from large cell size are found among the colorless sulfur bacteria that oxidize hydrogen sulfide to sulfate with oxygen or nitrate, which have become independent of the coexistence of their substrates. Expand
Can entropy save bacteria
A physical biology approach to understanding organization and segregation of bacterial chromosomes using a "piston" analogy for bacterial chromosomes in a cell, which leads to a phase diagram for the organization of two athermal chains confined in a closed geometry characterized by two length scales. Expand
Viscoelasticity of the bacterial cell envelope
Efforts to characterize the mechanical properties of the bacterial cell envelope are reviewed, and recent advances in measurement techniques for individual bacterial cells that have led to a more complete understanding are highlighted. Expand
Box-shaped halophilic bacteria
Three morphologically similar strains of halophilic, box-shaped procaryotes have been isolated from brines collected in the Sinai, Baja California (Mexico), and southern California and contain pigments similar to bacteriorhodopsin which apparently mediate light-driven ion translocation and photophosphorylation. Expand


On the gas vacuoles of the halobacteria
SummaryThe cells of Halobacterium sp., strain 5, contain a large number of highly refractile bodies of the type which Petter (1932) suggested were gas-filled vacuoles. The present studies supportExpand
Comparative Study of the Structure of Gas Vacuoles
The gas vacuole appears to be a homologous organelle in all of these procaryotic groups, and its presence in the gas vesicles of the green bacterium Pelodictyon clathratiforme was inferred from thin sections. Expand
Blue-Green Algae: Fine Structure of the Gas Vacuoles
The gas vacuoles seen in several species of blue-green algae under the light microscope are shown by electron microscopy to correspond to packed arrays of cylindrical, electron-transparent vesicles.Expand
The pressure relationships of gas vacuoles
  • A. Walsby
  • Chemistry
  • Proceedings of the Royal Society of London. Series B. Biological Sciences
  • 1971
The gas vacuoles which occur in various prokaryotic organisms can be estimated quantitatively by the change in light scattering which takes place when they are destroyed by pressure. The gradualExpand
On the Structural Transformations and Lysis of Halobacterium salinarium in Hypotonic and Isotonic Solution s
SUMMARY When the NaCl concentration of a suspension of Halobacterium salinarium is gradually lowered by adding water, the rod-shaped organisms are converted to spheres which lyse. The organisms doExpand
Isolation and Purification of Intact Gas Vesicles from a Blue–Green Alga
THE gas vesicles which make up the gas vacuoles of blue–green algae collapse flat on application of a few atmospheres pressure1 and this frustrates attempts to isolate them intact by methods of cellExpand
Simonsiellaceae fam.nov.with characterization of Simonsiella crassa and Alysiella filiformis.
  • P. Steed
  • Biology, Medicine
  • Journal of general microbiology
  • 1962
The multicellular filaments of both Simonsiella and Alysiella, originally termed “disk-bacteria”, are ribbon-like, non-sporing,non-branching, aerobic and Gram-negative. Expand
Phylogenetic structure of the prokaryotic domain: The primary kingdoms
  • C. Woese, G. Fox
  • Biology, Medicine
  • Proceedings of the National Academy of Sciences of the United States of America
  • 1977
A phylogenetic analysis based upon ribosomal RNA sequence characterization reveals that living systems represent one of three aboriginal lines of descent: the eubacteria, comprising all typical bacteria, the archaebacteria, and the urkaryotes, now represented in the cytoplasmic component of eukaryotic cells. Expand