scholarly journals Myosin subfragment binding for the localization of actin-like microfilaments in cultured cells. A light and electron microscope study.

1977 ◽  
Vol 74 (3) ◽  
pp. 794-815 ◽  
Author(s):  
J A Schloss ◽  
A Milsted ◽  
R D Goldman
Keyword(s):  
Electron Microscope ◽  
Cultured Cells ◽  
Light And Electron Microscopy ◽  
Embryo Cell ◽  
Exchange Chromatography ◽  
Rat Embryo ◽  
Mitotic Apparatus ◽  
Thin Sections ◽  
Before And After ◽  
Identical Manner

Fluorescein-labeled heavy meromyosin subfragment-1 (F-S-1) has been purified by ion exchange chromatography and characterized in terms of its ability to bind specifically to actin. F-S-1 activates the Mg++-adenosine triphosphatase activity of rabbit skeletal muscle actin and decorates actin as shown by negative stains and thin sections of rabbit actin and rat embryo cell microfilament bundles, respectively. Binding of F-S-1 to cellular structures is prevented by pyrophosphate and by competition with excess unlabeled S-1. The F-S-1 is used in light microscope studies to determine the distribution of actin-containing structures in wnterphase and mitotic rat embryo and rat kangaroo cells. Interphase cells display the familiar pattern of fluorescent stress fibers. Chromosome-to-pole fibers are fluorescent in mitotic cells. The glycerol extraction procedures employed provide an opportunity to examine cells prepared in an identical manner by light and electron microscopy. The latter technique reveals that actin-like microfilaments are identifiable in spindles of glycerinated cells before and after addition of S-1 or HMM. In some cases, microfilaments appear to be closely associated with spindle microtubles. Comparison of the light and electron microscope results aids in the evaluation of the fluorescent myosin fragment technique and provides further evidence for possible structural and functional roles of actin in the mitotic apparatus.

Electron Microscope Studies of Anti-Antibodies

1968 ◽  
Vol 26 ◽  
pp. 50-51
Author(s):  
J. P. Robinson ◽  
R. D. Robinson
Keyword(s):  
Electron Microscope ◽  
Immune Complexes ◽  
Uranyl Acetate ◽  
Low Ph ◽  
Positive Staining ◽  
Acid Media ◽  
Thin Sections ◽  
Before And After ◽  
The Subject ◽  
Partial Dissociation

The presence of anti-antibodies in sera was first proposed by Najjar and Fisher in 1955. There have subsequently been numerous demonstrations of anti-antibodies and the subject was recently reviewed.According to Najjar's proposal there should be at least two distinguishable types of antibodies involved in the formation of immune complexes. The first antibody is specific for the antigen while the second, anti-antibody, is directed against the antibody portion of the immune complex.This report involves visualizing the anti-antibody portion of complexes by positive staining. It also demonstrates their removal from equivalence complex in acid media.Thin sections of equivalence complex were prepared before and after partial dissociation by exposure to pH 2. 8. The sections were stained by floating on uranyl acetate solutions. Fig. 1 illustrates a preparation of equivalence complex while Fig. 2 shows the remainder of a complex partially dissociated at low pH. Equivalence complex contains large areas of interacting anti-antibodies which are detected by the absence of ferritin molecules. Such areas are greatly reduced or removed from the complex in Fig. 2. Normal γ-globulin mixed with ferritin forms no precipitate.

Reconstruction tridimensionnelle du chondriome de Ginkgo en culture tissulaire; étude au moyen de coupes épaisses et de coupes fines sériées

1979 ◽  
Vol 57 (4) ◽  
pp. 332-340 ◽  
Author(s):  
René Rohr
Keyword(s):  
Electron Microscope ◽  
Cultured Cells ◽  
Three Dimensional ◽  
The Other ◽  
Important Place ◽  
Thin Sections ◽  
Dimensional Models ◽  
Complete Cell ◽  
Three Dimensional Models

The observation of thick sections and serial thin sections with the electron microscope demonstrates a reticular organization of mitochondria in cultured cells from Ginkgo. Thick sections show that most of the mitochondria fuse either in loose networks made up of elongated elements or in dense clusters composed of globular units. Serial thin sections enable us to prove the true reticular nature of the mitochondrial organization; most of the mitochondrial profiles are part of highly fused and branched networks. These mitochondrial reticula (about two to three per cell) occupy an important place within the cell. Some mitochondria remain isolated or they fuse slightly. Two three-dimensional models have been built: the first one constructed with cardboard sheets is used to display the organization of a reticulum; the other of Plexiglas clearly indicates the relative positions and the form of mitochondria in a complete cell. The mitochondria, plastids, and vacuoles of this cell are also measured and enumerated.

Modification for Electron Miscroscopy of the Corbett Ammoniacal Silver Stain

1971 ◽  
Vol 29 ◽  
pp. 484-485
Author(s):  
Robert L. Corbett
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Light Microscopy ◽  
Low Power ◽  
Light And Electron Microscopy ◽  
Glass Slide ◽  
Silver Stain ◽  
Thin Sections ◽  
Silver Deposits ◽  
Ammoniacal Silver

The ammoniacal silver stain for light microscopy of plastic embedded sections has been adapted for use in electron microscopy. Since the silver will stain even very thin sections, i.e., silver and gold for light microscopy, and silver deposits are sufficiently electron dense to be seen in the electron microscope, the results are very useful for correlating light and electron microscopy. Compared to the conventional stains for electron microscopy which usually take over one-half hour, the silver procedure can be done in five minutes or less and thus provides a quick look at sections This stain has more contrast, so it is especially good for low power electron microscopy. The ability of the silver to stain very thin sections enables a correlation between light and electron microscopy in three ways. First, thin sections can be stained with silver on a glass slide and compared with immediately adjacent thin sections on grids stained the usual way for electron microscopy.

scholarly journals FIBRILLAR DIFFERENTIATION IN MYXOMYCETE PLASMODIA

1965 ◽  
Vol 25 (2) ◽  
pp. 305-318 ◽  
Author(s):  
Sister M. A. McManus ◽  
L. E. Roth
Keyword(s):  
Electron Microscope ◽  
Molecular Species ◽  
Physarum Polycephalum ◽  
Mitotic Apparatus ◽  
Thin Sections ◽  
Fixation Methods ◽  
Different Types ◽  
Protoplasmic Movement

Myxomycete plasmodia of four different types (not including Physarum polycephalum) were studied in thin sections viewed in the electron microscope. In the cytoplasm of the protoplasmodia of Clastoderma debaryanum and the phaneroplasmodia of Fuligo septica fixed in situ, fibrillar differentiations of three rather distinct kinds were observed. One of these is filamentous and closely resembles the filaments (or "microtubules") of the mitotic apparatus of other species. The larger phaneroplasmodia of two species belonging to the Physarales and the plasmodium of Hemitrichia vesparium showed fewer and less well defined fibrils, and no fibrils were seen in the aphanoplasmodium of Stemonitis fusca. Good stabilization of such fibrils in larger plasmodia may require fixation methods more rigidly controlled than those which succeed with microscopic protoplasmodia. The function of the observed fibrils cannot yet be determined. Their presence in cytoplasm fixed in situ, however, lends support to those theories of protoplasmic movement which are dependent on integral cross-bonding of one or a few molecular species.

The Structure and Some Properties of the Isolated Mitotic Apparatus

1969 ◽  
Vol 4 (1) ◽  
pp. 179-209
Author(s):  
R. D. GOLDMAN ◽  
L. I. REBHUN
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Structural Changes ◽  
Close Association ◽  
Light And Electron Microscopy ◽  
Mitotic Apparatus ◽  
Isolation Medium ◽  
Oriented Parallel ◽  
Differential Interference Microscope

The morphology of the isolated sea-urchin mitotic apparatus (MA) was examined by light and electron microscopy. With the polarization microscope and the Nomarski differential interference microscope, the isolated MAs appeared to be similar to in vivo MAs. Electron microscopy of the isolated MAs revealed the presence of microtubules, ribosome-like particles and vesicles. A close association between the ribosome-like particles and the MA microtubules resulted in the appearance of chains of particles running along the length of the microtubules. Isolated MAs washed two to three times in isolation medium showed fine-structural changes in the electron microscope, which were reflected by lower retardation values obtained with the polarization microscope. The addition of magnesium and calcium or sucrose to the washing medium prevented these structural changes. Varying the pH of the isolation medium also resulted in changes in birefringence and ultrastructure of unwashed MAs. Isolated MAs stored in the original isolation medium gradually became less birefringent and lost their microtubules. At pH 6.1 and pH 6.2 a residual birefringence was retained, even after several weeks of storage. Electron microscopy of these MAs revealed the presence of linear aggregates of ribosome-like particles oriented parallel to the long axis of the spindle. On the other hand, at pH 6.3and pH 6.4, MAs lost their birefringence completely, and the ribosome-like particles became more randomly dispersed. 2M sucrose or 0.003 M Mg2+ greatly retarded the loss of birefringence in stored MAs. Glutaraldehyde-fixed MAs stained intensely with azure B bromide, demonstrating the presence of RNA. Treatment with RNase resulted in a loss of this staining. RNase-treated MAs examined with the electron microscope, revealed changes in the ribosome-like particles. The results are discussed in the light of recent biochemical analyses of the isolated MA, structural similarities to in situ MAs and the interpretation of the birefringence of the MA.

scholarly journals The Relation between the Axial Complex of Meiotic Prophase Chromosomes and Chromosome Pairing in a Salamander (Plethodon cinereus)

1958 ◽  
Vol 4 (5) ◽  
pp. 633-638 ◽  
Author(s):  
Montrose J. Moses
Keyword(s):  
Electron Microscope ◽  
Meiotic Prophase ◽  
Light And Electron Microscopy ◽  
Central Element ◽  
Primary Spermatocyte ◽  
Plethodon Cinereus ◽  
Axial Complex ◽  
Thin Sections ◽  
Single Chromosome ◽  
Synaptinemal Complex

An investigation of the structure of meiotic chromosomes from primary spermatocytes of two salamanders, Plethodon cinereus and Desmognathus fusca, has been made using correlated light and electron microscopy. Feulgen squashes were compared with stained sections and these related to adjacent thin sections in the electron microscope. A transition from the familiar cytological preparation to the electron image was thus effected. A linear complex consisting of three parallel strands has been observed with the electron microscope, passing along the central axis of primary spermatocyte chromosomes. The complex is similar to that found in comparable chromosomes from at least a dozen animal species. The structure in Plethodon is described in detail. Synapsis has been positively identified as the stage of meiotic prophase at which the complex occurs. Thus the complex is a part of bivalent chromosomes. It has not been seen in other stages or other divisions and is thus thought to be exclusively of synaptic occurrence. The term synaptinemal complex is suggested for the entire structure. By virtue of the material condensed around it, the complex is also seen in the light microscope where it appears as a fine, densely Feulgen-positive central core along the chromosome. The complex is thus closely associated with DNA, if not at least in part, composed of it. In the stages studied, homologous chromosomes are not always completely paired. The lateral elements of the complex separate and follow the single chromosome axes at these points. The central element disappears and thus may be a phenomenon of pairing. It is concluded that the lateral elements of the synaptinemal complex may more correctly be a "core" of the single meiotic prophase chromosome, possibly being concerned with its linear organization.

Probing the ultrastructure of the mitotic and meiotic spindle in eggs: An expeditious approach based on semi-thin (0.25 μm) serial sections

1983 ◽  
Vol 41 ◽  
pp. 552-555
Author(s):  
Conly L. Rieder ◽  
S. Bowser ◽  
R. Nowogrodzki ◽  
K. Ross ◽  
G. Sluder
Keyword(s):  
Small Sample Size ◽  
Small Sample ◽  
Meiotic Spindle ◽  
Serial Sections ◽  
Mitotic Apparatus ◽  
Thin Sections ◽  
Cell Cycles ◽  
Ultrastructural Studies

Eggs have long been a favorite material for studying the mechanism of karyokinesis in-vivo and in-vitro. They can be obtained in great numbers and, when fertilized, divide synchronously over many cell cycles. However, they are not considered to be a practical system for ultrastructural studies on the mitotic apparatus (MA) for several reasons, the most obvious of which is that sectioning them is a formidable task: over 1000 ultra-thin sections need to be cut from a single 80-100 μm diameter egg and of these sections only a small percentage will contain the area or structure of interest. Thus it is difficult and time consuming to obtain reliable ultrastructural data concerning the MA of eggs; and when it is obtained it is necessarily based on a small sample size.We have recently developed a procedure which will facilitate many studies concerned with the ultrastructure of the MA in eggs. It is based on the availability of biological HVEM's and on the observation that 0.25 μm thick serial sections can be screened at high resolution for content (after mounting on slot grids and staining with uranyl and lead) by phase contrast light microscopy (LM; Figs 1-2).

Unusual Intranuclear Structures in Chick Sympathetic Neurons

1967 ◽  
Vol 25 ◽  
pp. 188-189
Author(s):  
E. B. Masurovsky ◽  
H. H. Benitez ◽  
M. R. Murray
Keyword(s):  
Electron Microscope ◽  
Sympathetic Neurons ◽  
Uranyl Acetate ◽  
Sympathetic Ganglia ◽  
Lead Citrate ◽  
Thin Sections ◽  
Cns Neurons ◽  
Mammalian Cns

Recent light- and electron microscope studies concerned with the effects of D2O on the development of chick sympathetic ganglia in long-term, organized culture revealed the presence of rod-like fibrillar formations, and associated granulofibrillar bodies, in the nuclei of control and deuterated neurons. Similar fibrillar formations have been reported in the nuclei of certain mammalian CNS neurons; however, related granulofibrillar bodies have not been previously described. Both kinds of intranuclear structures are observed in cultures fixed either in veronal acetate-buffered 2%OsO4 (pH 7. 4), or in 3.5% glutaraldehyde followed by post-osmication. Thin sections from such Epon-embedded cultures were stained with ethanolic uranyl acetate and basic lead citrate for viewing in the electron microscope.

An Electron Microscope Study of Interdiffusion and Compound Formation in Ta-Au Thin Films

1973 ◽  
Vol 31 ◽  
pp. 32-33 ◽  
Author(s):  
T. C. Tisone ◽  
S. Lau
Keyword(s):  
Electron Microscope ◽  
Electron Microscope Study ◽  
Thermally Grown Oxide ◽  
Ion Milling ◽  
Compound Formation ◽  
Technology Application ◽  
Transmission Electron ◽  
Before And After ◽  
Au Thin Films

In a study of the properties of a Ta-Au metallization system for thin film technology application, the interdiffusion between Ta(bcc)-Au, βTa-Au and Ta2M-Au films was studied. Considered here is a discussion of the use of the transmission electron microscope(TEM) in the identification of phases formed and characterization of the film microstructures before and after annealing.The films were deposited by sputtering onto silicon wafers with 5000 Å of thermally grown oxide. The film thicknesses were 2000 Å of Ta and 2000 Å of Au. Samples for TEM observation were prepared by ultrasonically cutting 3mm disks from the wafers. The disks were first chemically etched from the silicon side using a HNO3 :HF(19:5) solution followed by ion milling to perforation of the Au side.

Fine Structure of Interdental Cells in the Mouse Cochlea

1970 ◽  
Vol 28 ◽  
pp. 140-141
Author(s):  
Roberta M. Bruck
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Young Adult ◽  
Uranyl Acetate ◽  
Ground Substance ◽  
Tectorial Membrane ◽  
Lead Citrate ◽  
Unusual Structure ◽  
Thin Sections ◽  
Collagenous Fibers

An unusual structure in the cochlea is the spiral limbus; this periosteal tissue consists of stellate fibroblasts and collagenous fibers embedded in a translucent ground substance. The collagenous fibers are arranged in vertical columns (the auditory teeth of Haschke). Between the auditory teeth are interdental furrows in which the interdental cells are situated. These epithelial cells supposedly secrete the tectorial membrane.The fine structure of interdental cells in the rat was reported by Iurato (1962). Since the mouse appears to be different, a description of the fine structure of mouse interdental cells' is presented. Young adult C57BL/6J mice were perfused intervascularly with 1% paraformaldehyde/ 1.25% glutaraldehyde in .1M phosphate buffer (pH7.2-7.4). Intact cochlea were decalcified in .1M EDTA by the method of Baird (1967), postosmicated, dehydrated, and embedded in Araldite. Thin sections stained with uranyl acetate and lead citrate were examined in a Phillips EM-200 electron microscope.

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