Lipid in Erysiphe graminis hordei and its possible role during germination

1970 ◽  
Vol 16 (11) ◽  
pp. 1041-1044 ◽  
Author(s):  
W. E. McKeen
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Osmium Tetroxide ◽  
Erysiphe Graminis ◽  
Glutaraldehyde Fixation ◽  
Sudan Black B ◽  
Erysiphe Graminis Hordei ◽  
Sudan Iv ◽  
Mother Cells ◽  
Hyphal Tip

Osmiophilic bodies appear in parts of the colonial growth of Erysiphe graminis DC. f. sp. hordei Em Marchal culture CR3 growing on the susceptible commercial Keystone variety of barley. They are readily observed by the light and electron microscope after osmium tetroxide staining and are abundant in conidiophores, conidia, and mycelium except in haustorial mother cells, in which they are usually absent. The metabolism of haustorial mother cells is distinct and the fine structure of adjoining cells is frequently different. Osmiophilic bodies are absent from the growing hyphal tip, but gradually increase in number and size further back in the terminal cell. Electron micrographs show that they are intracytoplasmic, intravacuolar, and up to 1 μ in diameter. When the colony is washed with acetone or alcohol rather than with aqueous buffer, after glutaraldehyde fixation, before osmium tetroxide fixation, the osmiophilic bodies are removed, indicating that they are lipids. Fat stains, Sudan black B, and Sudan IV stain these bodies. Perhaps the water needs of the germinating conidium are met in part by the oxidation of fats.

scholarly journals PRESERVATION OF MYELIN LAMELLAR STRUCTURE IN THE ABSENCE OF LIPID

1967 ◽  
Vol 34 (3) ◽  
pp. 817-826 ◽  
Author(s):  
Leonard Napolitano ◽  
Francis Lebaron ◽  
Joseph Scaletti
Keyword(s):  
Fatty Acids ◽  
Liquid Chromatography ◽  
Fine Structure ◽  
Electron Microscope ◽  
Lamellar Structure ◽  
Osmium Tetroxide ◽  
Gas Liquid Chromatography ◽  
Glutaraldehyde Fixation ◽  
Thin Sections ◽  
Sciatic Nerves

The fine structure of myelin was studied in glutaraldehyde-fixed rat sciatic nerves depleted of lipid by acetone, chloroform:methanol (2:1 v/v), and chloroform:methanol:concentrated HCl (200:100:1, v/v/v). One portion of each of these nerves, plus the extracts, was saponified and analyzed by gas-liquid chromatography for fatty acids. The remainder of each nerve was stained in osmium tetroxide in CCl4 (5g/100cc) and was embedded in Epon 812. Thin sections, examined in the electron microscope, revealed the preservation of myelin lamellar structure with a 170 A periodicity in nerves depleted of 98% of their lipids. Preservation of myelin lamellar structure depended on glutaraldehyde fixation and the introduction of osmium tetroxide in a nonpolar vehicle (CCl4) after the lipids had been extracted. It is concluded that the periodic lamellar structure in electron micrographs of myelin depleted of lipid results from the complexing of osmium tetroxide, plus uranyl and lead stains, with protein.

scholarly journals THE FINE STRUCTURE OF THE RAT CEREBELLUM

1964 ◽  
Vol 23 (2) ◽  
pp. 277-293 ◽  
Author(s):  
Robert M. Herndon
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Light Microscope ◽  
Osmium Tetroxide ◽  
Granule Cells ◽  
Cell Types ◽  
Bergmann Glia ◽  
Rat Cerebellum

This paper describes the fine structure of the granule cells, stellate neurons, astrocytes, Bergmann glia, oligodendrocytes, and microglia of the rat cerebellum after fixation by perfusion with buffered 1 per cent osmium tetroxide. Criteria are given for differentiating the various cell types, and the findings are correlated with previous light microscope and electron microscope studies of the cerebellum.

Fine Structure of the Nucleolus in Normal and Mutant Xenopus Embryos

1967 ◽  
Vol 2 (2) ◽  
pp. 151-162
Author(s):  
ELIZABETH D. HAY ◽  
J. B. GURDON
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Xenopus Laevis ◽  
Fibrous Material ◽  
Osmium Tetroxide ◽  
Wild Type ◽  
Granular Component ◽  
Basic Dyes ◽  
Fibrillar Component ◽  
Xenopus Laevis Embryos

Mutant and normal Xenopus laevis embryos (0-nu, 1-nu, 2-nu) were examined in the electron microscope after glutaraldehyde and/or osmium-tetroxide fixation. During cleavage both 0-nu and wild-type embryos contain multiple small nucleolar bodies, less than 1 µ in diameter, composed mainly of a fibrous material. By the end of cleavage or beginning of gastrulation, granular caps develop on the fibrous nucleolar bodies. In 1-and 2-nu cells, the multiple nucleolar bodies are replaced during gastrula and neurula stages by definitive nucleoli (2-5 µ in diameter) which contain abundant small (150 Å) granules intermingled with fibrous material. In 0-nu cells, one or two pseudonucleoli (1-3 µ in diameter) appear at about the same time that definitive nucleoli develop in wild-type cells. The multiple small nucleolar bodies disappear as the pseudonucleoli enlarge. Pseudonucleoli differ from definitive nucleoli in having a much smaller amount of the granular component, which is located as a cap on the periphery of the fibrous component and not mingled with it. The granular component of the 0-nu pseudonucleoli, however, is not distinguishable in its fine structure from the same component of normal nucleoli. In many 0-nu tadpoles at stage 41, the granular component of the nucleolus is entirely absent and the fibrillar component is very prominent. Both granular and fibrous components of the 0-nu pseudonucleoli contain RNA as judged by RNase sensitivity and staining affinity for basic dyes.

Chromocentres and The Synaptinemal Complex

1970 ◽  
Vol 6 (3) ◽  
pp. 655-667
Author(s):  
L. F. LA COUR ◽  
B. WELLS
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
The Other ◽  
Near Surface ◽  
Thin Sections ◽  
Restricted Movement ◽  
Homologous Chromosomes ◽  
Synaptinemal Complex ◽  
Mother Cells ◽  
Fibrillar Network

The 1-4 chromocentres seen in nuclei of Fritillaria lanceolata, which derive from fusion of heterochromatic segments situated proximal to the centromere in all but two of the 24 chromosomes, were studied with the electron microscope in thin sections of pollen mother cells at zygotene and pachytene, in respect of the synaptinemal complex. Prophase stages of meiosis in two plants were also surveyed briefly with the light microscope. The latter observations revealed that the timing of the separation of heterochromatic segments from chromocentres is genetically controlled. In one plant the segments were still contained in chromocentres at pachytene, whereas in the other they were free at zygotene. At this time they could be identified by a near-surface position in the nucleus and an even condensation concomitant with an absence of chromomeres. In thin section, the fine structure of the chromocentres in zygotene nuclei was distinctive in that the chromatin fibrils were less condensed and more widely dispersed than those in euchromatic regions. The fibrillar network was also interspersed with ‘clear areas’ or channels. After further chromosome condensation, the condensation of fibrils in the chromocentres became equivalent at pachytene to those in euchromatic regions. Synaptinemal complexes were seen at zygotene and pachytene both in euchromatic regions and chromocentres. Their presence in the chromocentres signifies that homologous chromosomes must have been closely paired in regions extending from the centromeres to the distal ends of the heterochromatic segments already at telophase of the last pre-meiotic mitosis. Configurations involving entangled pairs of axial cores, peculiar to zygotene and chromocentres and parts of euchromatic regions proximal to them, are interpreted as resulting from restricted movement.

Somatic mitosis in Erysiphe graminis hordei

1972 ◽  
Vol 18 (12) ◽  
pp. 1915-1922 ◽  
Author(s):  
W. E. McKeen
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Nuclear Membrane ◽  
Osmium Tetroxide ◽  
Central Body ◽  
Nuclear Division ◽  
Light And Electron Microscopy ◽  
Erysiphe Graminis ◽  
The Other ◽  
Erysiphe Graminis Hordei

Somatic nuclear division in Erysiphe graminis hordei was studied by light and electron microscopy after various fixation and staining procedures. Electron microscopy studies of alcohol – acetic acid fixed material aided in providing an understanding of nuclear division and showing the gross alterations which occurred. Light microscopy indicated that a central body was always present at a specific site on the nuclear membrane in the interphase nucleus and was connected to chromatic spherical bodies. Microtubules were preserved when a short glutaraldehyde – osmium tetroxide fixation was used. Some microtubules extend from plaque to plaque while others terminate in kinetochores. A microtubular spindle, oblique to the nuclear and mildew-cells axes formed within the nuclear membrane. Typical prophases, metaphases, anaphases, and telophases were observed. Then one set of daughter chromatids bypassed the nucleolus which persisted intranuclearly until the daughter nuclei reached their destination, and the other set of daughter chromatids moved to midpoint in the other daughter cell. A narrow corridor, which connected daughter nuclei for some time, was filled mainly with microtubules and probably was the filament which was observed in the nucleus by light microscopy during nuclear division. At least six chromosomes were present in each nucleus.

scholarly journals Electron Microscopy of Retinal Photoreceptors

1960 ◽  
Vol 7 (3) ◽  
pp. 493-497 ◽  
Author(s):  
Arnaldo Lasansky ◽  
Eduardo de Robertis
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Electron Microscope ◽  
Outer Segment ◽  
Osmium Tetroxide ◽  
The Other ◽  
Rod Outer Segments ◽  
Outer Segments ◽  
Retinal Photoreceptors ◽  
L1 And L2

The fine structure of the cone and rod outer segments of the toad was studied under the electron microscope after fixation in osmium tetroxide and fixation in formaldehyde followed by chromation. In the OsO4-fixed specimens, the rod outer segment appears to be built of a stack of lobulated flattened sacs, each of which is made of two membranes of about 40 A separated by an innerspace of about 30 A. The distance between the rod sacs is about 50 A. The sacs in the cone outer segment are originated by the folding of a continuous membrane. The thickness of the membranes and width of the spaces between the cone sacs is the same as in rod, but the sac innerspace is slightly narrower in the cone (∼ 20 A). After fixation in formaldehyde and chromation, two different dense lines (l1 and l2) separated by spaces of less density appear. One of the lines, l1, has a thickness of 70 A and is less dense than the other, l2, which is 30 A thick. The correlation of the patterns obtained with both fixatives is considered and two possible interpretations are given. The possibility that l2 is related to a soluble phospholipid component is discussed. It is suggested that the outer segments have a paracrystallin organization similar to that found in myelin.

scholarly journals STUDIES ON CILIA

1963 ◽  
Vol 18 (2) ◽  
pp. 345-365 ◽  
Author(s):  
Peter Satir
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Cross Section ◽  
Osmium Tetroxide ◽  
Freshwater Mussel ◽  
Structure And Function ◽  
Spring Water ◽  
Fine Structure And Function ◽  
And Function ◽  
Active Preparation

Upon excision into spring water, the lateral cilia of the gill of the freshwater mussel Elliptio complanatus (Solander) stop beating, but 0.04 M potassium ion can activate the gill so that these cilia again beat with metachronal rhythm. One per cent osmium tetroxide quickly pipetted onto a fully activated gill fixes the lateral cilia in a pattern that preserves the form and arrangement of the metachronal wave, and permits the cilia to be studied with the electron microscope in all stages of their beat cycle. Changes are seen in the fixed active preparation that are not present in the inactive control, i.e., in the packing of the cilia, the position of the axis of the ciliary cross-section, and the diameter of the ring of peripheral filaments. Analysis of these parameters may lead to new correlations between ciliary fine structure and function.

Bacterioids in the Rectal Organ of the Lantern Dug Pyrops Candelaria Linn (Homoptera: Fulgoridae)

1996 ◽  
Vol 54 ◽  
pp. 806-807
Author(s):  
W.W.K. Cheung ◽  
J.B. Wang
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Osmium Tetroxide ◽  
Uranyl Acetate ◽  
Sodium Cacodylate Buffer ◽  
Lead Citrate ◽  
Sodium Cacodylate ◽  
Special Pair ◽  
Adult Females ◽  
Cacodylate Buffer

The lantern bug harbours three symbionts, namely a, x and i in its body. These microorganisms are supposed to be transmitted transovarially to the future progeny. The x-symbionts are found in a special pair of organs called the x-organ which bulges to form a rectal organ in adult females. The purpose of this study is to investigate into the fine structure of the x-symbionts. This will serve as a basis for understanding the interactions of this microorganism with its host.The rectum of the lantern bug Pyrops candelaria Linn, was dissected out in buffered insect saline and fixed in 2.5% glutaradehyde in 0.1M sodium cacodylate buffer (pH 7.2) for 1 hr. The rectal organ was subsequently post-fixed in 1% osmium tetroxide (pH 7.2) and dehydrated in alcohol/acetone series. These were blocked in Spurr resin and cut with a Reichert Ultratome. Sections were stained with uranyl acetate and lead citrate and examined with a JEOL JEM-1200EX electron microscope. Thick sections (1 μn) were stained with 1% toluidine blue and examined under a Nikon Optiphot light microscope.

scholarly journals SARCOLEMMAL INVAGINATIONS CONSTITUTING THE T SYSTEM IN FISH MUSCLE FIBERS

1964 ◽  
Vol 22 (3) ◽  
pp. 675-696 ◽  
Author(s):  
Clara Franzini-armstrong ◽  
Keith R. Porter
Keyword(s):  
Fine Structure ◽  
Osmium Tetroxide ◽  
Striated Muscle ◽  
Muscle Fibers ◽  
Fish Muscle ◽  
Structural Features ◽  
The Body ◽  
Glutaraldehyde Fixation ◽  
Striated Muscle Fibers ◽  
T System

Striated muscle fibers from the body and tail myotomes of a fish, the black Mollie, have been examined with particular attention to the sarcoplasmic reticulum (SR) and transverse tubular (or T) system. The material was fixed in osmium tetroxide and in glutaraldehyde, and the images provided by the two kinds of fixatives were compared. Glutaraldehyde fixes a fine structure that is broadly comparable with that preserved by osmium tetroxide alone but differs in some significant details. Especially significant improvements were obtained in the preservation of the T system, that is, the system of small tubules that pervades the fiber at every Z line or A-I junction level. As a result of this improved glutaraldehyde fixation, the T system is now clearly defined as an entity of fine structure distinct from the SR but uniquely associated with the SR and myofibrils. Glutaraldehyde fixation also reveals that the T system is a sarcolemmal derivative that retains its continuity with the sarcolemma and limits a space that is in direct communication with the extracellular environment. These structural features favor the conclusion that the T system plays a prominent role in the fast intracellular conduction of the excitatory impulse. The preservation of other elements of muscle fine structure, including the myofibrils, seems for reasons discussed, to be substantially improved by glutaraldehyde.

scholarly journals FURTHER ELECTRON MICROSCOPE STUDIES ON FIBRILLAR ORGANIZATION OF THE GROUND CYTOPLASM OF CHAOS CHAOS

1968 ◽  
Vol 38 (1) ◽  
pp. 40-50 ◽  
Author(s):  
Vivianne T. Nachmias
Keyword(s):  
Electron Microscope ◽  
Alcian Blue ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Negative Staining ◽  
Glutaraldehyde Fixation

Further evidence for fibrillar organization of the ground cytoplasm of Chaos chaos is presented. Fixations with osmium tetroxide at pH 6 or 8 and with glutaraldehyde at pH 6 or 7 were used on two preparations: (a) single actively streaming cells; (b) prechilled cells treated with 0.05% Alcian blue in the cold and returned to room temperature for 5–10 min. In addition, a 50,000 g pellet of homogenized cells was examined after fixation with glutaraldehyde-formaldehyde alone. In sections from actively streaming cells considerable numbers of filaments were observed in the uroid regions after glutaraldehyde fixation, whereas only traces of filaments were seen after osmium tetroxide fixation at either pH 6 or 8. Microtubules were not seen. In sections from dye-treated cells, filaments (4–6 mµ) and fibrils (12–15 mµ) were found with all three fixatives. The 50,000 g pellet was heterogeneous but contained both clumps of fibrils and single thick fibrils like those seen in the cytoplasm of dye-treated cells. Many fibrils of the same dimensions (12–15 mµ wide, 0.5 µ long) were also seen in the supernatant above the pellet. Negative staining showed that some fibrils separated into at least three strands of 4–6 mµ filaments.

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