scholarly journals THE FINE STRUCTURE AND MODE OF ATTACHMENT OF THE SHEATHED FLAGELLUM OF VIBRIO METCHNIKOVII

1963 ◽  
Vol 18 (2) ◽  
pp. 327-336 ◽  
Author(s):  
Audrey M. Glauert ◽  
D. Kerridge ◽  
R. W. Horne
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Thin Sections ◽  
Basal Disc ◽  
The Core ◽  
Thin Sectioning ◽  
Potassium Phosphotungstate ◽  
Mode Of Attachment

The sheathed flagellum of Vibrio metchnikovii was chosen for a study of the attachment of the flagellum to the bacterial cell. Normal and autolysed organisms and isolated flagella were studied by electron microscopy using the techniques of thin sectioning and negative staining. The sheath of the flagellum has the same layered structure as the cell wall of the bacterium, and in favourable thin sections it appears that the sheath is a continuation of the cell wall. After autolysis the sheath is usually absent and the core of the flagellum has a diameter of 120 A. Electron micrographs of autolysed bacteria negatively stained with potassium phosphotungstate show that the core ends in a basal disc just inside the plasma membrane. The basal disc is about 350 A in diameter and is thus considerably smaller than the "basal granules" described previously by other workers.

The fine structure of Sphaerotilus nutans

1973 ◽  
Vol 19 (3) ◽  
pp. 309-313 ◽  
Author(s):  
Judith F. M. Hoeniger ◽  
H.-D. Tauschel ◽  
J. L. Stokes
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Lateral Position ◽  
Thin Sections ◽  
Liquid Cultures ◽  
Sphaerotilus Natans ◽  
Stationary Liquid ◽  
Basal Disk ◽  
Polar Organelle

Sphaerotilus natans developed sheathed filaments in stationary liquid cultures and motile swarm cells in shaken ones. Electron microscopy of negatively stained preparations and thin sections showed that the sheath consists of fibrils. When the filaments were grown in broth with glucose added, the sheath was much thicker and the cells were packed with granules of poly-β-hydroxybutyrate.Swarm cells possess a subpolar tuft of 10 to 30 flagella and a polar organelle which is usually inserted in a lateral position and believed to be ribbon-shaped. The polar organelle consists of an inner layer joined by spokes to an accentuated plasma membrane. The flagellar hook terminates in a basal disk, consisting of two rings, which is connected by a central rod to a second basal disk.

scholarly journals THE FINE STRUCTURE OF STALKED BACTERIA BELONGING TO THE FAMILY CAULOBACTERACEAE

1964 ◽  
Vol 23 (3) ◽  
pp. 587-607 ◽  
Author(s):  
Jeanne L. Stove Poindexter ◽  
Germaine Cohen-Bazire
Keyword(s):  
Cell Wall ◽  
Fine Structure ◽  
Cell Membrane ◽  
Multilayered Structure ◽  
Gram Negative Bacteria ◽  
Thin Sections ◽  
Gram Negative ◽  
Cytoplasmic Region ◽  
The Core ◽  
The Family

The fine structure of a series of stalked bacteria belonging to the genera Caulobacter and Asticcacaulis has been examined in thin sections. The cell wall has the multilayered structure typical of many Gram-negative bacteria, and continues without interruption throughout the length of the stalk. The core of the stalk, continuous with the cytoplasmic region of the cell, is enclosed in an extension of the cell membrane, and contains a system of internal membranes: it is devoid of ribosomes and nucleoplasm. A membranous organelle occupies the juncture of stalk and cell, separating the ribosomal region from the core of the stalk. Typical mesosomes also occur in the cell, being particularly frequent at the plane of division. The secreted holdfast is located at the tip of the stalk in Caulobacter, and at the pole of the cell adjacent to the stalk in Asticcacaulis.

Fine structure of Arthrobacter crystallopoietes during long-term starvation of rod and spherical stage cells

1973 ◽  
Vol 19 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Charles W. Boylen ◽  
Jack L. Pate
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Fine Structure ◽  
Cell Size ◽  
Morphological Changes ◽  
Thin Sections ◽  
Size And Shape ◽  
Arthrobacter Crystallopoietes ◽  
Total Starvation

Actively growing spherical and rod-shaped cells of Arthrobacter crystallopoietes were subjected to total starvation in buffer for 8 weeks. At intervals, thin sections of cells were prepared and examined by electron microscopy. Starving cells underwent no morphological changes that would account for their unusual survival capabilities. Cell size and shape remained unaltered. There was no thickening of the cell wall and no development of structures similar to those observed in spores or cysts. As the length of starvation increased, the following changes were observed; glycogen deposits disappeared, the number of ribosome particles decreased, the number of vesicular membranes increased within the cell, and the nucleoplasm expanded in volume to fill the emptying cytoplasm.

CYTOLOGY OF PHAGE-INFECTED STREPTOMYCES GRISEUS HYPHAE

1965 ◽  
Vol 11 (1) ◽  
pp. 103-107
Author(s):  
C. M. Gilmour ◽  
E. B. Bradford
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Streptomyces Griseus ◽  
Membrane Disruption ◽  
Hexagonal Shape ◽  
Ultrathin Sections ◽  
Irregular Cell

The fine structure of phage-infected Streptomyces griseus hyphae was examined using ultrathin sections and electron microscopy. The intracellular phage was observed to be uniformly distributed throughout the cytoplasm. The diameter and hexagonal shape of the head compared well with shadowed phage preparations. Alterations in fine structure centered on irregular cell wall disintegration, plasma membrane disruption, and leakage of cytoplasmic components.

Fine structure of normal and regenerated shell of Helix

1971 ◽  
Vol 49 (1) ◽  
pp. 37-41 ◽  
Author(s):  
A. S. M. Saleuddin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fine Structure ◽  
Organic Matrix ◽  
Nacreous Layer ◽  
Replica Technique ◽  
Thin Sections ◽  
Thin Sectioning ◽  
Inorganic Components ◽  
Scanning Electron

Fine structure of the normal and the regenerated shell of Helix has been studied by thin sectioning, replica technique, and scanning electron microscopy. Normal shell consists of four calcareous layers: innermost nacreous, two cross lamellar, and outermost prismatic. Crystals of the shell are well defined and are surrounded by intercrystalline organic matrix. Intracrystalline organic matrix is recognized, particularly in decalcified sections. Interrelationships between the organic and inorganic components have been studied in decalcified thin sections. Regenerated shell appears similar to nacreous layer of the normal shell. Crystals are large and stacked like bricks. Intracrystalline organic matrix is very prominent. Electron diffraction of the crystals of the regenerated shell generally gives calcite pattern whereas the normal shell gives aragonite. Surface topography of the normal and regenerated shell has been compared by replica techniques.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

Lead aspartate: a new en bloc stain for electron microscopy

1978 ◽  
Vol 36 (2) ◽  
pp. 34-35
Author(s):  
J.R. Walton
Keyword(s):  
Electron Microscopy ◽  
Calcium Ion ◽  
Enzyme Reaction ◽  
Lead Citrate ◽  
Reaction Products ◽  
En Bloc ◽  
Thin Sections ◽  
Lead Salts ◽  
Thin Sectioning ◽  
High Alkalinity

In electron microscopy, lead is the metal most widely used for enhancing specimen contrast. Lead citrate requires a pH of 12 to stain thin sections of epoxy-embedded material rapidly and intensively. However, this high alkalinity tends to leach out enzyme reaction products, making lead citrate unsuitable for many cytochemical studies. Substitution of the chelator aspartate for citrate allows staining to be carried out at pH 6 or 7 without apparent effect on cytochemical products. Moreover, due to the low, controlled level of free lead ions, contamination-free staining can be carried out en bloc, prior to dehydration and embedding. En bloc use of lead aspartate permits the grid-staining step to be bypassed, allowing samples to be examined immediately after thin-sectioning.Procedures. To prevent precipitation of lead salts, double- or glass-distilled H20 used in the stain and rinses should be boiled to drive off carbon dioxide and glassware should be carefully rinsed to remove any persisting traces of calcium ion.

scholarly journals FINE STRUCTURE OF THE GRAM-NEGATIVE BACTERIUM ACETOBACTER SUBOXYDANS

1964 ◽  
Vol 20 (2) ◽  
pp. 217-233 ◽  
Author(s):  
G. W. Claus ◽  
L. E. Roth
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Cell Walls ◽  
Negative Staining ◽  
Homogeneous Layer ◽  
Physical Treatment ◽  
Thin Sections ◽  
Gram Negative ◽  
Acetobacter Suboxydans ◽  
Negative Cell

The morphological features of the cell wall, plasma membrane, protoplasmic constituents, and flagella of Acetobacter suboxydans (ATCC 621) were studied by thin sectioning and negative staining. Thin sections of the cell wall demonstrate an outer membrane and an inner, more homogeneous layer. These observations are consistent with those of isolated, gram-negative cell-wall ghosts and the chemical analyses of gram-negative cell walls. Certain functional attributes of the cell-wall inner layer and the structural comparisons of gram-negative and gram-positive cell walls are considered. The plasma membrane is similar in appearance to the membrane of the cell wall and is occasionally found to be folded into the cytoplasm. Certain features of the protoplasm are described and discussed, including the diffuse states of the chromatinic material that appear to be correlated with the length of the cell and a polar differentiation in the area of expected flagellar attachment. Although the flagella appear hollow in thin sections, negative staining of isolated flagella does not substantiate this finding. Severe physical treatment occasionally produces a localized penetration into the central region of the flagellum, the diameter of which is much smaller then that expected from sections. A possible explanation of this apparent discrepancy is discussed.

scholarly journals Initial events during phagocytosis by macrophages viewed from outside and inside the cell: membrane-particle interactions and clathrin.

1982 ◽  
Vol 94 (3) ◽  
pp. 613-623 ◽  
Author(s):  
J Aggeler ◽  
Z Werb
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Plasma Membranes ◽  
Cell Attachment ◽  
High Resolution Electron Microscopy ◽  
Peritoneal Macrophages ◽  
Coated Pits ◽  
Thin Sections ◽  
Particle Uptake ◽  
Freeze Dried

The initial events during phagocytosis of latex beads by mouse peritoneal macrophages were visualized by high-resolution electron microscopy of platinum replicas of freeze-dried cells and by conventional thin-section electron microscopy of macrophages postfixed with 1% tannic acid. On the external surface of phagocytosing macrophages, all stages of particle uptake were seen, from early attachment to complete engulfment. Wherever the plasma membrane approached the bead surface, there was a 20-nm-wide gap bridged by narrow strands of material 12.4 nm in diameter. These strands were also seen in thin sections and in replicas of critical-point-dried and freeze-fractured macrophages. When cells were broken open and the plasma membrane was viewed from the inside, many nascent phagosomes had relatively smooth cytoplasmic surfaces with few associated cytoskeletal filaments. However, up to one-half of the phagosomes that were still close to the cell surface after a short phagocytic pulse (2-5 min) had large flat or spherical areas of clathrin basketwork on their membranes, and both smooth and clathrin-coated vesicles were seen fusing with or budding off from them. Clathrin-coated pits and vesicles were also abundant elsewhere on the plasma membranes of phagocytosing and control macrophages, but large flat clathrin patches similar to those on nascent phagosomes were observed only on the attached basal plasma membrane surfaces. These resulted suggest that phagocytosis shares features not only with cell attachment and spreading but also with receptor-mediated pinocytosis.

scholarly journals The fine structure produced in cells by primary fixatives 2. Potassium dichromate

1965 ◽  
Vol s3-106 (73) ◽  
pp. 15-21
Author(s):  
JOHN R. BAKER
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Golgi Apparatus ◽  
Nuclear Membrane ◽  
Osmium Tetroxide ◽  
Potassium Dichromate ◽  
Potassium Dichromate Solution ◽  
Zymogen Granules ◽  
Mouse Pancreas

The exocrine cells of the mouse pancreas were fixed in potassium dichromate solution, embedded in araldite or other suitable medium, and examined by electron microscopy. Almost every part of these cells is seriously distorted or destroyed by this fixative. The ergastoplasm is generally unrecognizable, the mitochondria and zymogen granules are seldom visible, and no sign of the plasma membrane, microvilli, or Golgi apparatus is seen. The contents of the nucleus are profoundly rearranged. It is seen to contain a large, dark, irregularly shaped, finely granular object; the evidence suggests that this consists of coagulated histone. The sole constituent of the cell that is well fixed is the inner nuclear membrane. The destructive properties of potassium dichromate are much mitigated when it is mixed in suitable proportions with osmium tetroxide or formaldehyde.

Sign in / Sign up

Export Citation Format

Share Document