Some Observations on the Nucleolus in Spirogyra

1969 ◽  
Vol 4 (1) ◽  
pp. 3-15
Author(s):  
E. G. JORDAN ◽  
M. B. E. GODWARD
Keyword(s):  
Electron Microscopy ◽  
Light Microscope ◽  
Osmium Tetroxide ◽  
The Other ◽  
Clear Association ◽  
Nucleolar Material ◽  
Two Stages ◽  
Mitotic Cells

Several species of Spirogyra have been collected and fixed for electron microscopy in either 2% osmium tetroxide or 5% glutaraldehyde. Mitotic cells were selected with the light microscope from filaments of Spirogyra embedded in Epon. Evidence is given for an interphase cycle in the nucleolus of Spirogyra. A clear association between nucleolar material and chromosomes occurs at mitosis. The breakdown of the nucleolus is shown to occur in two stages, one as a consequence of the withdrawal of the nucleolar chromosomes, and the other after telophase in the new nucleus. The significance of these findings is discussed.

Comparative strengths and weaknesses of peroxidase and colloidal gold in pre- and post-embedding immunolabeling techniques

1987 ◽  
Vol 45 ◽  
pp. 1002-1005
Author(s):  
D. R. Abrahamson ◽  
P. L. St.John ◽  
E. W. Perry
Keyword(s):  
Electron Microscopy ◽  
Horseradish Peroxidase ◽  
Light Microscopy ◽  
Colloidal Gold ◽  
Light Microscope ◽  
Ultrastructural Localization ◽  
The Other ◽  
Quantitative Studies ◽  
Dense Suspension ◽  
Antigen Localization

Antibodies coupled to tracers for electron microscopy have been instrumental in the ultrastructural localization of antigens within cells and tissues. Among the most popular tracers are horseradish peroxidase (HRP), an enzyme that yields an osmiophilic reaction product, and colloidal gold, an electron dense suspension of particles. Some advantages of IgG-HRP conjugates are that they are readily synthesized, relatively small, and the immunolabeling obtained in a given experiment can be evaluated in the light microscope. In contrast, colloidal gold conjugates are available in different size ranges and multiple labeling as well as quantitative studies can therefore be undertaken through particle counting. On the other hand, gold conjugates are generally larger than those of HRP but usually can not be visualized with light microscopy. Concern has been raised, however, that HRP reaction product, which is exquisitely sensitive when generated properly, may in some cases distribute to sites distant from the original binding of the conjugate and therefore result in spurious antigen localization.

scholarly journals THE FINE STRUCTURE OF THE NUCLEOLUS DURING MITOSIS IN THE GRASSHOPPER NEUROBLAST CELL

1965 ◽  
Vol 24 (3) ◽  
pp. 349-368 ◽  
Author(s):  
Barbara J. Stevens
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Light Microscope ◽  
Light And Electron Microscopy ◽  
Peripheral Zone ◽  
Structural Components ◽  
Thin Sections ◽  
Nucleolar Material ◽  
Central Regions ◽  
Homogeneous Background

The behavior of the nucleolus during mitosis was studied by electron microscopy in neuroblast cells of the grasshopper embryo, Chortophaga viridifasciata. Living neuroblast cells were observed in the light microscope, and their mitotic stages were identified and recorded. The cells were fixed and embedded; alternate thick and thin sections were made for light and electron microscopy. The interphase nucleolus consists of two fine structural components arranged in separate zones. Concentrations of 150 A granules form a dense peripheral zone, while the central regions are composed of a homogeneous background substance. Observations show that nucleolar dissolution in prophase occurs in two steps with a preliminary loss of the background substance followed by a dispersal of the granules. Nucleolar material reappears at anaphase as small clumps or layers at the chromosome surfaces. These later form into definite bodies, which disappear as the nucleolus grows in telophase. Evidence suggests both a collecting and a synthesizing role for the nucleolus-associated chromatin. The final, mature nucleolar form is produced by a rearrangement of the fine structural components and an increase in their mass.

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.

The fine structure of the trunk and praesoma wall of Acanthocephalus ranae (Schrank, 1788), Lühe, 1911

Parasitology ◽  
1967 ◽  
Vol 57 (3) ◽  
pp. 475-486 ◽  
Author(s):  
R. A. Hammond
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Electron Microscope ◽  
Light Microscope ◽  
Body Wall ◽  
Technical Assistance ◽  
The Body ◽  
The Other ◽  
Fat Excretion ◽  
Research Grant

The wall of the trunk, that of the praesoma, and the lemnisci of Acanthocephalus ranae have been studied by electron microscopy. Striations visible in sections of the body wall under the light microscope do not correspond with the ‘striped layer’ revealed by the electron microscope.A new region, the ‘canal layer’, has been described. This contains canals running into the body wall from cuticular pores.Structurally the wall of the trunk and that of the praesoma are similar. The lemnisci resemble the ‘inner layer’ of the praesoma wall. However, it is suggested that the wall of the trunk differs physiologically from that of the praesoma, and from the lemnisci. The possible roles of the wall of the praesoma and the lemnisci in fat excretion or uptake have been discussed.The body wall of A. ranae has been compared with that of the other acantho-cephalans studied with the electron microscope.Grateful acknowledgement is made to D.S.I.R. (now S.R.C.) for a research grant to the Department of Zoology for the purchase of a Huxley ultramicrotome, a vacuum coating unit, and an AEI EM 6 electron microscope.I am grateful to Dr D. A. Erasmus for reading and criticizing the manuscript, and to Mr T. Davies for valuable technical assistance.

X-ray microanalytical and enzyme-cytochemical study on vesical malacoplakia

1978 ◽  
Vol 36 (2) ◽  
pp. 646-647
Author(s):  
Masami Hokano ◽  
Tsunao Oh-I ◽  
Yoshie Narita ◽  
Hiroshi Sassa ◽  
Saburo Suzuki
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Osmium Tetroxide ◽  
Granulomatous Inflammation ◽  
Uranyl Acetate ◽  
The Other ◽  
Lead Citrate ◽  
Cytochemical Study ◽  
X Ray ◽  
Ultrathin Sections

Malacoplakia is a kind of granulomatous inflammation and characterized by the presence of calcium-stain positive granules (Michaelis-Gutmann bodies, hereinafter abbreviated as M-G bodies ) in the macrophages.In this report we want to say about the following articles:the ultrastruc tural findings in four cases of vesical malacoplakia;the ultrastructural morphogenesis of the M-G bodies;X-ray microanalytical studies which examine the change of the chemical component of M-G bodies, according to their developing stages; andacid phosphatase activity of lysosome within the malacoplakic macrophages.Biopsy materials taken from four cases with vesical malacoplakia were divided into 2 parts; one for a light microscopy and the other for an electron microscopy. The specimen for an electron microscopy was fixed in glutaraldehyde and osmium tetroxide, dehydrated in ethanol and then embedded in Epon 812. Ultrathin sections were doublestained with lead citrate and uranyl acetate and then subjected to routin TEM observation. For X-ray microanalysis was mounted an energy dispersive X-ray microanalyzer on a JEM-100 C type electron microscope. Ultrathin sections for microanalysis were cut 100-200nm thich and not stained.

Cytological Effects of Ultra-High Temperatures on Corn

Weed Science ◽  
1973 ◽  
Vol 21 (4) ◽  
pp. 299-303 ◽  
Author(s):  
T. C. Ellwanger ◽  
S. W. Bingham ◽  
W. E. Chappell ◽  
S. A. Tolin
Keyword(s):  
Electron Microscopy ◽  
Zea Mays ◽  
High Temperatures ◽  
Light Microscope ◽  
Osmium Tetroxide ◽  
Bundle Sheath ◽  
Membrane Systems ◽  
Mesophyll Cells ◽  
Bundle Sheath Cells ◽  
Sheath Cells

Corn (Zea mays L. ‘Funk's G-83’) seedling leaves exposed to flame-generated ultra-high temperatures produced in flame cultivation were fixed in glutaraldehyde, post fixed in osmium tetroxide, and embedded in Araldite. In the light microscope, bundle sheath cells of flamed tissue were more heavily stained with Azure II and less vacuolated than were nonflamed cells. Heated mesophyll cells contained swollen, disrupted, and granular chloroplasts. Examination of flamed tissue by electron microscopy revealed granular, dispersed cytaplasm and altered membrane systems. Chloroplast lamellar systems and envelopes, tonoplasts, and plasmalemmas were disintegrated in both bundle sheath and mesophyll cells.

Spontaneous Cataract in Nude Athymic Mice

1977 ◽  
Vol 35 ◽  
pp. 512-513
Author(s):  
Ronald H. Bradley ◽  
R. S. Berk ◽  
L. D. Hazlett
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Nude Mouse ◽  
Cellular Immunity ◽  
Phosphate Buffer ◽  
Osmium Tetroxide ◽  
Athymic Mice ◽  
Transmission Microscopy ◽  
Mouse Lens ◽  
Scanning Electron

The nude mouse is a hairless mutant (homozygous for the mutation nude, nu/nu), which is born lacking a thymus and possesses a severe defect in cellular immunity. Spontaneous unilateral cataractous lesions were noted (during ocular examination using a stereomicroscope at 40X) in 14 of a series of 60 animals (20%). This transmission and scanning microscopic study characterizes the morphology of this cataract and contrasts these data with normal nude mouse lens.All animals were sacrificed by an ether overdose. Eyes were enucleated and immersed in a mixed fixative (1% osmium tetroxide and 6% glutaraldehyde in Sorenson's phosphate buffer pH 7.4 at 0-4°C) for 3 hours, dehydrated in graded ethanols and embedded in Epon-Araldite for transmission microscopy. Specimens for scanning electron microscopy were fixed similarly, dehydrated in graded ethanols, then to graded changes of Freon 113 and ethanol to 100% Freon 113 and critically point dried in a Bomar critical point dryer using Freon 13 as the transition fluid.

Scanning and Transmission Microscopy of Nematocyst Batteries in Epitheliomuscular Cells of Hydra

1971 ◽  
Vol 29 ◽  
pp. 410-411 ◽  
Author(s):  
Jane A. Westfall ◽  
S. Yamataka ◽  
Paul D. Enos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Osmium Tetroxide ◽  
External Surface ◽  
Three Dimensional ◽  
Surface Structures ◽  
Transmission Microscopy ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Scanning Electron

Scanning electron microscopy (SEM) provides three dimensional details of external surface structures and supplements ultrastructural information provided by transmission electron microscopy (TEM). Animals composed of watery jellylike tissues such as hydras and other coelenterates have not been considered suitable for SEM studies because of the difficulty in preserving such organisms in a normal state. This study demonstrates 1) the successful use of SEM on such tissue, and 2) the unique arrangement of batteries of nematocysts within large epitheliomuscular cells on tentacles of Hydra littoralis.Whole specimens of Hydra were prepared for SEM (Figs. 1 and 2) by the fix, freeze-dry, coat technique of Small and Màrszalek. The specimens were fixed in osmium tetroxide and mercuric chloride, freeze-dried in vacuo on a prechilled 1 Kg brass block, and coated with gold-palladium. Tissues for TEM (Figs. 3 and 4) were fixed in glutaraldehyde followed by osmium tetroxide. Scanning micrographs were taken on a Cambridge Stereoscan Mark II A microscope at 10 KV and transmission micrographs were taken on an RCA EMU 3G microscope (Fig. 3) or on a Hitachi HU 11B microscope (Fig. 4).

Development of 200 kV Scanning-Transmission Electron Microscope

1974 ◽  
Vol 32 ◽  
pp. 410-411
Author(s):  
H. Koike ◽  
S. Sakurai ◽  
K. Ueno ◽  
M. Watanabe
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Transmission Electron Microscope ◽  
The Other ◽  
Morphological Observation ◽  
Magnetic Domains ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Backscattered Electron ◽  
Increasing Demand

In recent years, there has been increasing demand for higher voltage SEMs, in the field of surface observation, especially that of magnetic domains, dislocations, and electron channeling patterns by backscattered electron microscopy. On the other hand, the resolution of the CTEM has now reached 1 ∼ 2Å, and several reports have recently been made on the observation of atom images, indicating that the ultimate goal of morphological observation has beem nearly achieved.

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