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… 
Gas vesicles
A survey of gas-vacuolate cyanobacteria reveals that there has been natural selection for gas vesicles of the maximum width permitted by the pressure encountered in the natural environment, which is mainly determined by cell turgor pressure and water depth.
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.
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.
Archaea with square cells.
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.
The Selective Value of Bacterial Shape
  • K. Young
  • Biology
    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.
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.
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.
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.
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.


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.
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.
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 gradual
On the Structural Transformations and Lysis of Halobacterium salinarium in Hypotonic and Isotonic Solution s
The observations support the contention that the globular lipoprotein particles, which constitute the bulk of the material of the cell wall of Halobacterium salinarium, are bound together mainly by electrostatic forces and secondary bonds.
Isolation and Purification of Intact Gas Vesicles from a Blue–Green Alga
A novel method of lysing blue–green algal cells, the isolation of their intact gas vesicles and a preliminary investigation into the composition of theGas vesicle membrane are described.
Simonsiellaceae fam.nov.with characterization of Simonsiella crassa and Alysiella filiformis.
  • P. Steed
  • Biology
    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.
Phylogenetic structure of the prokaryotic domain: The primary kingdoms
  • C. Woese, G. Fox
  • Biology
    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.