Teliospores of Entorrhiza casparyana (Ustilaginales): a correlated thin-sectioning and freeze–fracture study of endogenously dormant spores

1984 ◽  
Vol 62 (12) ◽  
pp. 2525-2539 ◽  
Author(s):  
Brian A. Fineran ◽  
Judith M. Fineran
Keyword(s):  
Outer Layer ◽  
Freeze Fracture ◽  
Middle Layer ◽  
Wall Material ◽  
Lipid Bodies ◽  
Freeze Fracturing ◽  
Thin Sectioning ◽  
Single Nucleus ◽  
Fracture Study ◽  
Small Clusters

A correlated thin-sectioning and freeze–fracturing approach was used to reveal the ultrastructure of endogenously dormant teliospores in the smut fungus Entorrhiza casparyana (Magn.) Lagerh. Conventional fixation and embedding methods yielded poor preservation of the wall and protoplasm. Successful preservation was achieved by fixing frozen and cryosectioned spores in glutaraldehyde and subsequently processing by standard procedures for transmission electron microscopy. Freeze–fracturing provided cross- and contour-fractured views of the protoplasm and the different layers of the wall. The wall is thick, consisting of three main layers: outer, middle, and inner, with the outer and inner layers further differentiated into zones. The warty zone dominates the outer layer and consists of radial protuberances (warts) with the regions between filled to varying degrees with similar wall material containing electron-transparent lamellae. The extent of differentiation of the warty zone is reflected in the surface morphology of the spores, which ranges from verrucose to almost smooth. At the base of the outer layer is an electron-translucent irregular zone. The middle and inner layers are regular in thickness around the spore, with the middle layer being the most electron dense. The inner layer is differentiated into three zones. The most distinctive is zone 2 which in freeze–fractured walls has an unique mosaic of striae. Cytochemical staining of the wall for polysaccharide material gives a positive reaction only for the warty zone. The protoplasm contains a single nucleus and is dominated by numerous spheroidal storage lipid bodies. Squeezed among the lipid bodies are organelles, believed to be microbodies, containing a granular matrix and often electron-transparent areas. These organelles failed to show catalase activity with the 3,3′-diaminobenzidine method. Occasional short profiles of endoplasmic reticulum cisternae, a few mitochondria with sparse cristae, dispersed small clusters of glycogen, and sometimes scattered ribosomes are also present in the cytoplasm. All these features are typical of dormant spores with a low metabolic activity.

Ultrastructure of Staphylococcus epidermidis after freeze-etching and thin sectioning

1973 ◽  
Vol 19 (2) ◽  
pp. 294-295
Author(s):  
James E. Gilchrist ◽  
Irving W. DeVoe
Keyword(s):  
Staphylococcus Aureus ◽  
Outer Layer ◽  
Staphylococcus Epidermidis ◽  
Cell Walls ◽  
Cytoplasmic Membrane ◽  
Middle Layer ◽  
Dense Layer ◽  
Thin Sections ◽  
Thin Sectioning ◽  
Freeze Etching

A considerable quantity of information is now available on the ultrastructure of Staphylococcus (1, 2, 4, 7, 8, 10, 11, 12). Cell walls of these organisms in thin sections have been shown to consist of three layers: a dense outer layer, a rather electron translucent middle layer, and a very dense layer next to the cytoplasmic membrane (2, 7, 11, 12). Bulger and Bulger (2) have pointed out the presence of circumferential substructure in the middle layer of the wall in a strain of Staphylococcus aureus isolated as the causative agent in fatal pneumonia.Numerous mesosomes of both the vesicular and laminar types are evident in thin sections of staphylococci from several studies (1, 4, 7, 11). Moreover, single vesicular structures that appear to be invaginations of the trilaminar cytoplasmic membrane have been pointed out by Suganuma (11) and Beaton (1).

scholarly journals Ultrastructure of the sodium pump: Comparison of thin sectioning, negative staining, and freeze-fracture of purified, membrane-bound (Na+, K+)-ATPase

1977 ◽  
Vol 75 (3) ◽  
pp. 619-634 ◽  
Author(s):  
N Deguchi ◽  
PL Jorgensen ◽  
AB Maunsbach
Keyword(s):  
Membrane Surface ◽  
Freeze Fracture ◽  
Negative Staining ◽  
Intramembranous Particle ◽  
Freeze Fracturing ◽  
Intramembranous Particles ◽  
Membrane Surfaces ◽  
Thin Sectioning ◽  
Surface Particle ◽  
Protein Components

Purified (Na+, K+)-ATPase was studied by electron microscopy after thin sectioning, negative staining, and freeze-fracturing, particular emphasis being paid to the dimensions and frequencies of substructures in the membranes. Ultrathin sections show exclusively flat or cup-shaped membrane fragments which are triple-layered along much of their length and have diameters of 0.1-0.6 μm. Negative staining revealed a distinct substructure of particles with diameters between 30 and 50 A and with a frequency of 12,500 +/- 2,400 (SD) per μm(2). Comparisons with sizes of the protein components suggest that each surface particle contains as its major component one large catalytic chain with mol wt close to 100,000 and that two surface particles unite to form the unit of (Na+,K+)-ATPase which binds one molecule of ATP or ouabain. The further observations that the surface particles protrude from the membrane surface and are observed on both membrane surfaces in different patterns and degrees of clustering suggest that protein units span the membrane and are capable of lateral mobility. Freeze-fracturing shows intramembranous particles with diameters of 90-110 A and distributed on both concave and convex fracture faces with a frequency of 3,410 +/- 370 per μm(2) and 390 +/- 170 per μm(2), respectively. The larger diameters and three to fourfold smaller frequency of the intramembranous particles as compared to the surface particles seen after negative staining may reflect technical differences between methods, but it is more likely that the intramembranous particle is an oliogomer composed of two or even more of the protein units which form the surface particles.

A freeze-fracture study of the cuticle of adult Nippostrongylus brasiliensis (Nematoda)

Parasitology ◽  
1993 ◽  
Vol 107 (5) ◽  
pp. 545-552 ◽  
Author(s):  
D. L. Lee ◽  
K. A. Wright ◽  
R. R. Shivers
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Freeze Fracture ◽  
Surface Coat ◽  
Nippostrongylus Brasiliensis ◽  
Freeze Fracturing ◽  
Transmission Electron ◽  
Fracture Study ◽  
20 Nm

SUMMARYThe surface of the cuticle of adult Nippostrongylus brasiliensis has been studied by means of the freeze-fracture technique and by transmission electron microscopy. Some of the surface coat appears to have been shed from the surface of the cuticle of adults fixed in situ in the intestine of its host and from the surface of individuals removed from the intestine and freeze-fractured. Freeze-fracturing the cuticle of individuals removed from the host has shown that this surface coat varies in thickness from 30 to 90 nm. The epicuticle is about 20 nm thick and cleaves readily to expose E- and P-faces. The P-face of the epicuticle possesses a small number of particles, similar to intra-membranous particles, whilst the E-face possesses a few, widely scattered depressions. Despite the presence of these particles the epicuticle is not considered to be a true membrane. Freeze-fracturing the remainder of the cuticle has confirmed its structure as described by conventional transmission electron microscopy. Clusters of particles on the P-face of the outer epidermal (hypodermal) membrane and corresponding depressions on the E-face of the membrane are thought to be associated with points of attachment of the cuticle to the epidermis (hypodermis). No differences in appearance of the cuticle and its surface layers were observed in individuals taken from 7-, 10-, 13- and 15-day infections.

Correlative SEM, freeze-fracture, and laser scanning microscopy of Tilletia controversa teliospore sheath morphology

1992 ◽  
Vol 50 (1) ◽  
pp. 850-851
Author(s):  
Kimberly A. Rowe ◽  
John S. Gardner ◽  
W.M. Hess
Keyword(s):  
Outer Layer ◽  
Laser Scanning ◽  
Freeze Fracture ◽  
Laser Scanning Microscopy ◽  
Scanning Microscopy ◽  
Specimen Preparation ◽  
Thin Sectioning ◽  
Tilletia Controversa ◽  
Sem Studies

The bunts of wheat are infected by Tilletia which have teliospores with complex multilayered walls. The outer layer or sheath of Tilletia controversa teliospores is difficult to characterize unless it is hydrated. The morphology of the sheath has been characterized with freeze-fracture, thin sectioninging and SEM studies. By using specialized, time-consuming thin-sectioning specimen preparation procedures the sheath can be a factor in distinguishing T. caries and T. controversa teliospores. Distinguishing the species is important for marketing wheat. The purpose of these investigations was to develop better methods to characterize the sheath which will help to distinguish teliospores of these two species and races of Tilletia much more easily and quickly.

Ultrastructure of basidiospores of the mycorrhizal fungus Pisolithus tinctorius

1980 ◽  
Vol 58 (14) ◽  
pp. 1525-1533 ◽  
Author(s):  
Charles W. Mims
Keyword(s):  
Lipid Droplet ◽  
Outer Layer ◽  
Mycorrhizal Fungus ◽  
Distal Portion ◽  
Pisolithus Tinctorius ◽  
The Other ◽  
Wall Material ◽  
Large Lipid Droplet ◽  
Single Nucleus ◽  
Cellular Components

Basidia of Pisolithus tinctorius develop from terminal hyphal cells. The distal portion of the basidium enlarges, meiosis occurs, and basidiospore initials develop on short, stout, sterigmata, Young basidia and basidiospore initials are embedded in a fibrillar matrix. As spore initials develop, the basidium becomes highly vacuolate as the contents of the basidium move into the spore initials. A single nucleus typically enters each spore initial. A spore initial is eventually delimited from the basidium near the distal end of the sterigma. Wall material is subsequently deposited in this region sealing off the young spore from the basidium. The basidium then collapses leaving the short sterigma attached to the spore. Young basidiospores are initially highly vacuolate but a large lipid droplet eventually develops and displaces the other cellular components to the periphery of the spore. The oldest spores examined possessed a four-layered wall, the outer layer of which bears the surface spines. Many aberrant spores possessing more or less typical surface spines but lacking cellular components were routinely observed in this study side by side with normal spores.

Freeze-fracture observations on changes in the distribution of Filipin-sterol complexes during epididymal maturation and capacitation of boar spermatozoa

1990 ◽  
Vol 48 (3) ◽  
pp. 90-91
Author(s):  
N. Seki ◽  
Y. Toyama ◽  
T. Nagano
Keyword(s):  
Plasma Membrane ◽  
Essential Role ◽  
Freeze Fracture ◽  
Final Concentration ◽  
Freeze Fracturing ◽  
Physiological Conditions ◽  
Epididymal Maturation ◽  
Cacodylate Buffer ◽  
Sperm Membrane ◽  
Boar Spermatozoa

It is believed that i ntramembra.nous sterols play an essential role in membrane stability and permeability. To investigate the distribution changes of sterols in sperm membrane during epididymal maturation and capacitation, filipin has been used as a cytochemical probe for the detection for membrane sterols. Using this technique in combination with freeze fracturing, we examined the boar spermatozoa under various physiological conditions.The spermatozoa were collected from: 1) caput, corpus and cauda epididymides, 2) sperm rich fraction of ejaculates, and 3)the uterus 2hr after natural coition. They were fixed with 2.5% glutaraldehyde in 0.05M cacodylate buffer (pH 7.4), and treated with the filipin solution (final concentration : 0.02.0.05%) for 24hr at 4°C with constant agitation. After the filipin treatment, replicas were made by conventional freeze-fracture technique. The density of filipin-sterol complexes (FSCs) was determined in the E face of the plasma membrane of head regions.

scholarly journals ELECTRON MICROSCOPY OF THE NUCLEAR MEMBRANE OF AMOEBA PROTEUS

1956 ◽  
Vol 2 (4) ◽  
pp. 445-448 ◽  
Author(s):  
Marie H. Greider ◽  
Wencel J. Kostir ◽  
Walter J. Frajola
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Nuclear Membrane ◽  
Outer Layer ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Cell Types ◽  
Amoeba Proteus ◽  
Nuclear Membranes ◽  
Thin Sectioning

An electron microscope study of the nuclear membrane of Amoeba proteus by thin sectioning techniques has revealed an ultrastructure in the outer layer of the membrane that is homologous to the pores and annuli observed in the nuclear membranes of many other cell types studied by these techniques. An inner honeycombed layer apparently unique to Amoeba proteus is also described.

Sign in / Sign up

Export Citation Format

Share Document