Formation, growth and regeneration of incomplete cell wall in spheroplasts of the blue-green algaAnacystis nidulans in liquid media

ABSTRACT We have isolated fission yeast mutants that constitutively flocculate upon growth in liquid media. One of these mutants, thegsf1 mutant, was found to cause dominant, nonsexual, and calcium-dependent aggregation of cells into flocs. Its flocculation was inhibited by the addition of galactose but was not affected by the addition of mannose or glucose, unlike Saccharomyces cerevisiae FLO mutants. The gsf1 mutant coflocculated withSchizosaccharomyces pombe wild-type cells, while no coflocculation was found with galactose-deficient (gms1Δ) cells. Moreover, flocculation of the gsf1 mutant was also inhibited by addition of cell wall galactomannan from wild-type cells but not from gms1Δ cells. These results suggested that galactose residues in the cell wall glycoproteins may be receptors ofgsf1-mediated flocculation, and therefore cell surface galactosylation is required for nonsexual flocculation in S. pombe.

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Selection of Mutants with Disorganized Septation and Transformation to L forms of Nocardia Corynebacterioides Nom Nov and N. asteroides

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100094917 ◽

1972 ◽

Vol 30 ◽

pp. 330-331

Author(s):

J. A. Serrano

Keyword(s):

Electron Microscopy ◽

Amino Acids ◽

Cell Wall ◽

Phase Contrast ◽

Smooth Surface ◽

Ammonium Carbonate ◽

Nocardia Asteroides ◽

Liquid Media ◽

The Media ◽

Selection Of

Morphology of the cell wall and organization of the cytoplasm of Nocardia corynebacterioides nom nov and Nocardia asteroides ATCC 14597, were examined by electron microscopy after the induction of autolysis using 0.012M ammonium carbonate. Organisms were cultured in casaminic acidbroth modified according to Abrams (1955), medium PPLO (Difco) modified according to Sharp (1954), a modified mixture of electrolytes according to Dienes (1956) and a medium based on amino-acids in proportions of 0.05 mg %. In all of these media we used in an alternate or combined form 1.000 U/ml of penicillin or 100 mg/ml of cycloserine (Sigma). After treatment in ammonium carbonate and culture in the media mentioned above, incubated at 37°C, the growth of the colonies on Agar-peptone and Agar-amino-acid presented a smooth surface and alterations of pigmentation.Cultures in solid or liquid media were observed by phase contrast and with a JEM 7-A electron microscope. The cells were negatively stained with sodium silicotungstate pH 7.6 and fixed in 2% osmium according to Ryter and Kellenberger.

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Variation in the expression of cell wall proteins of Staphylococcus aureus grown on solid and liquid media.

Infection and Immunity ◽

10.1128/iai.56.5.1061-1065.1988 ◽

1988 ◽

Vol 56 (5) ◽

pp. 1061-1065 ◽

Cited By ~ 65

Author(s):

A L Cheung ◽

V A Fischetti

Keyword(s):

Staphylococcus Aureus ◽

Cell Wall ◽

Cell Wall Proteins ◽

Liquid Media

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Influence of Cell Wall Composition on the Fossilisation of Bacteria and the Implications for the Search for Early Life Forms

International Astronomical Union Colloquium ◽

10.1017/s0252921100015025 ◽

1997 ◽

Vol 161 ◽

pp. 491-504 ◽

Cited By ~ 3

Author(s):

Frances Westall

Keyword(s):

Cell Wall ◽

Life Forms ◽

Cation Binding ◽

Positive Bacterium ◽

Gram Positive ◽

Gram Positive Bacteria ◽

Transmission Electron ◽

Hydrothermal Sediments ◽

Identification Of Bacteria ◽

The Difference

AbstractThe oldest cell-like structures on Earth are preserved in silicified lagoonal, shallow sea or hydrothermal sediments, such as some Archean formations in Western Australia and South Africa. Previous studies concentrated on the search for organic fossils in Archean rocks. Observations of silicified bacteria (as silica minerals) are scarce for both the Precambrian and the Phanerozoic, but reports of mineral bacteria finds, in general, are increasing. The problems associated with the identification of authentic fossil bacteria and, if possible, closer identification of bacteria type can, in part, be overcome by experimental fossilisation studies. These have shown that not all bacteria fossilise in the same way and, indeed, some seem to be very resistent to fossilisation. This paper deals with a transmission electron microscope investigation of the silicification of four species of bacteria commonly found in the environment. The Gram positiveBacillus laterosporusand its spore produced a robust, durable crust upon silicification, whereas the Gram negativePseudomonas fluorescens, Ps. vesicularis, andPs. acidovoranspresented delicately preserved walls. The greater amount of peptidoglycan, containing abundant metal cation binding sites, in the cell wall of the Gram positive bacterium, probably accounts for the difference in the mode of fossilisation. The Gram positive bacteria are, therefore, probably most likely to be preserved in the terrestrial and extraterrestrial rock record.

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Influence of Calcium Ions on the Plant Cell Surface: Membrane Fusions and Conformational Changes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100050780 ◽

1974 ◽

Vol 32 ◽

pp. 154-155

Author(s):

D. James Morré ◽

Charles E. Bracker ◽

William J. VanDerWoude

Keyword(s):

Cell Wall ◽

Cell Surface ◽

Conformational Changes ◽

Calcium Ions ◽

Surface Membrane ◽

Carboxyl Groups ◽

Cross Linking ◽

Ultrastructural Evidence ◽

Glycine Max L ◽

Wall Extensibility

Calcium ions in the concentration range 5-100 mM inhibit auxin-induced cell elongation and wall extensibility of plant stems. Inhibition of wall extensibility requires that the tissue be living; growth inhibition cannot be explained on the basis of cross-linking of carboxyl groups of cell wall uronides by calcium ions. In this study, ultrastructural evidence was sought for an interaction of calcium ions with some component other than the wall at the cell surface of soybean (Glycine max (L.) Merr.) hypocotyls.

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Freeze-Fracture Replication in the Ultrastructure of Blue-Green Algae

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100060386 ◽

1967 ◽

Vol 25 ◽

pp. 74-75

Author(s):

L. V. Leak

Keyword(s):

Cell Wall ◽

Electron Microscope ◽

Green Algae ◽

Three Dimensional ◽

Freeze Fracture ◽

Electron Microscopic ◽

Photosynthetic Membranes ◽

Blue Green Algae ◽

Cell Biol ◽

Cellular Components

Electron microscopic observations of freeze-fracture replicas of Anabaena cells obtained by the procedures described by Bullivant and Ames (J. Cell Biol., 1966) indicate that the frozen cells are fractured in many different planes. This fracturing or cleaving along various planes allows one to gain a three dimensional relation of the cellular components as a result of such a manipulation. When replicas that are obtained by the freeze-fracture method are observed in the electron microscope, cross fractures of the cell wall and membranes that comprise the photosynthetic lamellae are apparent as demonstrated in Figures 1 & 2.A large portion of the Anabaena cell is composed of undulating layers of cytoplasm that are bounded by unit membranes that comprise the photosynthetic membranes. The adjoining layers of cytoplasm are closely apposed to each other to form the photosynthetic lamellae. Occassionally the adjacent layers of cytoplasm are separated by an interspace that may vary in widths of up to several 100 mu to form intralamellar vesicles.

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Sites of Adsorption of the Bacteriophages T3 and T5 on the Wall of Escherichia Coli B.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100060490 ◽

1967 ◽

Vol 25 ◽

pp. 96-97

Author(s):

Manfred E. Bayer

Keyword(s):

Escherichia Coli ◽

Cell Wall ◽

Electron Microscope ◽

Uranyl Acetate ◽

E Coli ◽

Receptor Sites ◽

Rigid Cell Wall ◽

Host Cell Surface ◽

Bacterial Viruses ◽

Escherichia Coli B

Bacterial viruses adsorb specifically to receptors on the host cell surface. Although the chemical composition of some of the cell wall receptors for bacteriophages of the T-series has been described and the number of receptor sites has been estimated to be 150 to 300 per E. coli cell, the localization of the sites on the bacterial wall has been unknown.When logarithmically growing cells of E. coli are transferred into a medium containing 20% sucrose, the cells plasmolize: the protoplast shrinks and becomes separated from the somewhat rigid cell wall. When these cells are fixed in 8% Formaldehyde, post-fixed in OsO4/uranyl acetate, embedded in Vestopal W, then cut in an ultramicrotome and observed with the electron microscope, the separation of protoplast and wall becomes clearly visible, (Fig. 1, 2). At a number of locations however, the protoplasmic membrane adheres to the wall even under the considerable pull of the shrinking protoplast. Thus numerous connecting bridges are maintained between protoplast and cell wall. Estimations of the total number of such wall/membrane associations yield a number of about 300 per cell.

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