Ultrastructure of the cell wall of a Synechocystis strain

1980 ◽  
Vol 26 (2) ◽  
pp. 204-208 ◽  
Author(s):  
K. Lounatmaa ◽  
T. Vaara ◽  
K. Österlund ◽  
M. Vaara
Keyword(s):  
Cell Wall ◽  
Outer Membrane ◽  
Wall Layer ◽  
Ruthenium Red ◽  
Electron Microscopic ◽  
External Wall ◽  
Membrane Complex ◽  
Additional Layer ◽  
Hexagonal Arrangement ◽  
Ruthenium Red Staining

The ultrastructure of the cell wall of a Synechocystis strain, isolated from the Gulf of Finland, was studied using several electron microscopic techniques. This cyanobacterium has numerous projections which were observed to penetrate the cell wall complex. An additional layer (AL) was associated with the outer membrane. An additional external wall layer (EL) was connected to the outer membrane complex by thin fibers as revealed by ruthenium red staining. A hexagonal arrangement of the subunits in the additional external wall layer with a lattice constant of 15.5 nm was found.

Molecular Structure of the Outermost Cell Wall Component of Spirillum Serpens

1977 ◽  
Vol 35 ◽  
pp. 342-343
Author(s):  
Wah Chiu ◽  
David Grano
Keyword(s):  
Molecular Structure ◽  
Cell Wall ◽  
Outer Membrane ◽  
Gel Electrophoresis ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Cell Wall Component ◽  
Protein Components ◽  
Exposure Technique ◽  
Structural Aspects

The periodic structure external to the outer membrane of Spirillum serpens VHA has been isolated by similar procedures to those used by Buckmire and Murray (1). From SDS gel electrophoresis, we have found that the isolated fragments contain several protein components, and that the crystalline structure is composed of a glycoprotein component with a molecular weight of ∽ 140,000 daltons (2). Under an electron microscopic examination, we have visualized the hexagonally-packed glycoprotein subunits, as well as the bilayer profile of the outer membrane. In this paper, we will discuss some structural aspects of the crystalline glycoproteins, based on computer-reconstructed images of the external cell wall fragments.The specimens were prepared for electron microscopy in two ways: negatively stained with 1% PTA, and maintained in a frozen-hydrated state (3). The micrographs were taken with a JEM-100B electron microscope with a field emission gun. The minimum exposure technique was essential for imaging the frozen- hydrated specimens.

Morphology and ultrastructure of oral strains of Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus

1980 ◽  
Vol 30 (2) ◽  
pp. 588-600
Author(s):  
S C Holt ◽  
A C Tanner ◽  
S S Socransky
Keyword(s):  
Electron Microscopy ◽  
Ruthenium Red ◽  
Actinobacillus Actinomycetemcomitans ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Large Numbers ◽  
Haemophilus Aphrophilus ◽  
Ruthenium Red Staining ◽  
Amorphous Surface ◽  
Scanning Electron

Selected human oral and nonoral strains of the genera Actinobacillus and Haemophilus were examined by transmission and scanning electron microscopy. The strains examined were morphologically identical to recognized Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, and Haemophilus paraphrophilus. By transmission electron microscopy, the cells were typically gram negative in morphology, with several strains possessing some extracellular ruthenium red-staining polymeric material. Numerous vesicular structures, morphologically identical to lipopolysaccharide vesicles, were seen to originate from and be continuous with the surface of the outer membrane. Large numbers of these vesicles were also found in the external environment. Scanning electron microscopic observations revealed that both actinobacilli and haemophili possessed surface projections and an amorphous surface material which connected and covered adjacent cells.

Observation of exopolysaccharides (EPS) from Lactobacillus helveticus SBT2171 using the Tokuyasu method

Microscopy ◽  
2020 ◽  
Vol 69 (5) ◽  
pp. 286-290
Author(s):  
Takamichi Kamigaki ◽  
Akihiro Ogawa
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Colloidal Gold ◽  
Ruthenium Red ◽  
Lactobacillus Helveticus ◽  
Ruthenium Red Staining ◽  
Observation Method ◽  
Β Lactoglobulin

Abstract Some species of lactic acid bacteria used for the production of natural cheese produce exopolysaccharides (EPS). Electron microscopy is useful for analyzing the microstructure of EPS produced by lactic acid bacteria. However, pretreatments used to observe the microstructure of EPS by electron microscopy, such as dehydration and resin embedding, can result in EPS flowing out easily from the cell. Therefore, in this study, the Tokuyasu method was conducted on cryosection to reduce EPS outflow. Two types of observation method, namely, using lectin and ruthenium red, were conducted in an attempt to observe EPS produced by Lactobacillus helveticus SBT2171. Observation using the lectin method confirmed that colloidal gold particles conjugated with a lectin recognizing β-galactoside were present in the capsule. Structures that appeared to be β-galactoside-containing slime polysaccharides that were released from the cell wall were also observed. Observation using ruthenium red showed that capsular polysaccharides (CPS) in the capsule were present as a net-like structure. Colloidal gold conjugation with an anti-β-lactoglobulin antibody, in addition to ruthenium red staining, allowed the identification of slime polysaccharides released from the cell wall in the milk protein network derived from the culture medium. Based on these results, the Tokuyasu method was considered to be a useful pretreatment method to clarify and observe the presence of EPS. In particular, both CPS in the capsule and slime exopolysaccharides released from the cell wall were visualized.

Electron microscopic localization of sulfated glycosaminoglycans and proteoglycans in pleomorphic adenomas

1983 ◽  
Vol 41 ◽  
pp. 774-775
Author(s):  
Ronald Lam
Keyword(s):  
Electron Microscopy ◽  
Myoepithelial Cells ◽  
Mesenchymal Cells ◽  
Ruthenium Red ◽  
Major Salivary Gland ◽  
Electron Microscopic ◽  
Ultrastructural Studies ◽  
Pleomorphic Adenomas ◽  
Cellular Source ◽  
Ruthenium Red Staining

Although “myoepithelial” cells in pleomorphic adenomas have been implicated by several ultrastructural studies as responsible for the production of myxomatous and chondroid stroma, the cellular source of stromal glycosaminoglycans and proteoglycans has yet to be demonstrated histochemically by electron microscopy.Three major salivary gland pleomorphic adenomas were examined by electron microscopy after fixation in 2.5% glutaraldehyde and in 0.2% ruthenium red-glutaraldehyde. Routine ultrastructural preparations revealed a spectrum of cells with epithelial and mesenchymal features. The mesenchymal cells in the myxoid region displayed intracytoplasmic 70-80Å microfilaments, prominent Golgi complex, RER, and secretory vesicles. The fine structural appearance with ruthenium red stained tissue was similar to that of routine preparations. However, with ruthenium red staining, proteoglycans of the myxoid stroma could be visualized as numerous extracellular 250-500Å polygonal matrix granules with fine projecting filaments (Fig. 1A). Similar positive ruthenium red stained intracellular granules were observed within the cytoplasmic vacuoles of the mesenchymal cells, a feature not present in cells with epithelial differentiation (Fig. 1B).

Cell wall texture in root hairs of the genus Equisetum

1986 ◽  
Vol 64 (10) ◽  
pp. 2201-2206 ◽  
Author(s):  
Anne Mie C. Emons
Keyword(s):  
Cell Wall ◽  
Root Hair ◽  
Root Hairs ◽  
Wall Layer ◽  
Cell Wall Layer ◽  
Additional Layer ◽  
Cell Wall Texture ◽  
Helicoidal Texture

Based on cell wall texture of root hairs, two groups can be distinguished within the 10 species of Equisetum listed in Flora Europaea. This distinction coincides with the division of the genus Equisetum into two subgenera: Equisetum (horsetails) and Hippochaete (scouring rushes). All species of the subgenus Equisetum have a helicoidal cell wall texture in young growing root hairs as well as in full-grown hairs. All species of the subgenus Hippochaete deposit an additional inner cell wall layer against this helicoidal layer when elongation has stopped. The microfibrils in this additional layer do not form a helicoidal texture, but are helically arranged, forming a Z-helix. The presence of a helical layer in full-grown hairs is not a prerequisite for growth in soil, but an exclusively helicoidal root hair wall texture might be favourable for life in water. The wall texture is not influenced by the consistency of the substratum.

Ultrastructural changes in the myxamoebae of Physarum polycephalum in response to a microcyst-inducing concentration of mannitol

1984 ◽  
Vol 62 (2) ◽  
pp. 272-280 ◽  
Author(s):  
Lynda M. Williams ◽  
Jean-G. Lafontaine
Keyword(s):  
Cell Wall ◽  
Osmotic Potential ◽  
Physarum Polycephalum ◽  
Morphological Changes ◽  
Ruthenium Red ◽  
Ultrastructural Changes ◽  
Wall Material ◽  
Cell Wall Material ◽  
Cell Coat ◽  
Ruthenium Red Staining

The response of axenically cultured Physarum polycephalum myxamoebae to a microcyst-inducing concentration of mannitol (0.5 M) has been studied for both log-phase and maximum-concentration cultures. Results indicate that mannitol alone is not sufficient to induce encystment; a population effect is also necessary. Myxamoebae may continue to divide in the presence of mannitol if this effect is absent. Early ultrastructural changes have been noted indicating that the primary mode of action of mannitol is via the change in osmotic potential of the medium. Nuclear and cytoplasmic ultrastructural changes during the encystment process are documented. Recovery of log-phase cells to undergo mitosis involves definite morphological changes, which are also described. Ruthenium red staining was utilised to emphasize changes in the cell coat and indicate possible sites of accumulation of cell wall material.

An Electron Microscope Study of the Outer Layers of Barley Leaves Infected with Rhynchosporium secalis

1974 ◽  
Vol 1 (2) ◽  
pp. 313 ◽  
Author(s):  
CC Ryan ◽  
CJ Grivell
Keyword(s):  
Cell Wall ◽  
Outer Layer ◽  
Electron Microscope Study ◽  
Electron Microscopic Examination ◽  
Ruthenium Red ◽  
Electron Microscopic ◽  
Before And After ◽  
Barley Leaves ◽  
Epidermal Cell Wall ◽  
Wall Following

An electron microscopic examination was made of barley leaves before and after infection by R. secalis. Ruthenium red was used as an electron-opaque stain for pectic material. In uninfected leaves the adaxial surface consisted of wax, cuticle, pectic and inner and outer layer of the epidermal cell wall. Following penetration, infecting hyphae grew between the pectic layer and outer layer of the epidermal wall. The pectic and cuticular layers remained largely intact in leaf lesions until conidia were produced, whereas the cell wall was degraded and replaced by hyphae.

Freeze-etch study of the cell envelope of cowpea rhizobia: compartmentalization of the periplasmic space in relation to polysaccharide excretion

1990 ◽  
Vol 36 (6) ◽  
pp. 373-383 ◽  
Author(s):  
Bina Mody ◽  
Rustom Mody ◽  
Vinod Modi
Keyword(s):  
Outer Membrane ◽  
Cell Envelope ◽  
Ruthenium Red ◽  
Distinctive Features ◽  
Rhizobium Strains ◽  
Cytoplasmic Membranes ◽  
Rigid Cell Wall ◽  
Freeze Etching ◽  
Ruthenium Red Staining ◽  
Cowpea Rhizobia

Freeze-etching electron microscopy of free-living cowpea rhizobia revealed distinctive features of the cell envelope of this bacteria. The topology of the outer and cytoplasmic membranes was comparable with that described for other Gram-negative bacteria. In cowpea Rhizobium strains JLn(c) and NC-92, the rigid cell wall almost invariably cleaved away from the outer membrane, thus exposing two distinct fracture faces in the outer membrane, which to date have been ill defined in rhizobia. Cross-fractured cells showed enlargement of the periplasmic region as a result of invagination of the cytoplasmic membrane near one end of the cell. This feature was consistent in all exponential and stationary phase cells. Ruthenium red staining of cells in various growth phases showed unipolar initiation of the capsule. A unique structure seen within the enlarged periplasm was the presence of a smooth lipidic vesicle. Key words: Rhizobium, freeze-etch, membrane, polysaccharide, vesicle.

Sign in / Sign up

Export Citation Format

Share Document