scholarly journals Antibody-induced membrane fusion in Paramecium

1984 ◽  
Vol 65 (1) ◽  
pp. 153-162
Author(s):  
A. Barnett ◽  
E. Steers
Keyword(s):  
Electron Microscopy ◽  
Membrane Fusion ◽  
Phase Contrast ◽  
Immobilized Cells ◽  
Living Cells ◽  
Immune Serum ◽  
Induced Membrane ◽  
Transmission Electron ◽  
Membrane Changes ◽  
Antigen Antibody

Immobilization of cells by specific immune serum involves crosslinking between immunoglobulin G (IgG) and the i-antigen in the cell membrane. Globular material is seen to accumulate at the ciliary tips by phase-contrast and fluorescence microscopy in a manner analogous to ‘capping’ in more typical eukaryotes. When immobilized cells of Paramecium are examined by scanning electron microscopy, the fused ciliary tips are seen to be distended, discoidal membranes. Transmission electron microscopy often reveals several ciliary axonemes enclosed within a single, enlarged membrane that is oriented with the ferritin-labelled second antibody directed against the i-antigen antibody on the outer surface only. Fixed cells or living cells treated with immune Fab do not show membrane changes, but do bind antibody. Membrane fusion occurs only if cells are alive and the i-antigen is directly or indirectly cross-linked by intact immune IgG.

Imaging sub-micron objects with light microscopy: Visualization of the T-4 bacteriophage

1989 ◽  
Vol 47 ◽  
pp. 834-835
Author(s):  
Malcolm Brown ◽  
Reynolds M. Delgado ◽  
Michael J. Fink
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Focal Plane ◽  
Phase Contrast ◽  
Dark Field ◽  
E Coli ◽  
Polystyrene Beads ◽  
Television Camera ◽  
Transmission Electron ◽  
Universal Microscope

While light microscopy has been used to image sub-micron objects, numerous problems with diffraction-limitations often preclude extraction of useful information. Using conventional dark-field and phase contrast light microscopy coupled with image processing, we have studied the following objects: (a) polystyrene beads (88nm, 264nm, and 557mn); (b) frustules of the diatom, Pleurosigma angulatum, and the T-4 bacteriophage attached to its host, E. coli or free in the medium. Equivalent images of the same areas of polystyrene beads and T-4 bacteriophages were produced using transmission electron microscopy.For light microscopy, we used a Zeiss universal microscope. For phase contrast observations a 100X Neofluar objective (N.A.=1.3) was applied. With dark-field, a 100X planachromat objective (N.A.=1.25) in combination with an ultra-condenser (N.A.=1.25) was employed. An intermediate magnifier (Optivar) was available to conveniently give magnification settings of 1.25, 1.6, and 2.0. The image was projected onto the back focal plane of a film or television camera with a Carl Zeiss Jena 18X Compens ocular.

Dipetalonema viteae: ultrastructural study on the in vitro interaction between rat macrophages and microfilariae in the presence of IgE antibody

Parasitology ◽  
1981 ◽  
Vol 82 (1) ◽  
pp. 55-62 ◽  
Author(s):  
M. A. Ouaissi ◽  
A. Haque ◽  
A. Capron
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ultrastructural Study ◽  
Peritoneal Macrophages ◽  
Immune Serum ◽  
Sequence Of Events ◽  
Transmission Electron ◽  
Dipetalonema Viteae ◽  
In Vitro Interaction

SUMMARYThe in vitro interaction between rat peritoneal macrophages and Dipetalonema viteae microfilariae in the presence of amicrofilaraemic rat immune serum was studied by transmission electron microscopy. The probable sequence of events leading to the killing of D. viteae microfilaria by macrophages is as follows. (a) Rat peritoneal macrophages in the presence of amicrofilaraemic rat immune serum adhere to the parasite surface, (b) the macrophages extend their pseudopodia around the parasite, (c) the ‘lysosome-like’ granules discharge their contents on to the parasite surface, (d) the lytic activity of these products begins at the parasite surface and (e) subsequent breaking of the microfilarial cuticle occurs, exposing the parasite intracellular material.

Phase Contrast Enhancement with Phase Plates in Biological Electron Microscopy

2010 ◽  
Vol 18 (4) ◽  
pp. 10-13 ◽  
Author(s):  
Kuniaki Nagayama ◽  
Radostin Danev ◽  
Hideki Shigematsu ◽  
Naoki Hosogi ◽  
Yoshiyuki Fukuda ◽  
...  
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Phase Contrast ◽  
Phase Plate ◽  
Electron Loss ◽  
Whole Cells ◽  
Transmission Electron ◽  
Different Types ◽  
Transparent Objects ◽  
Phase Plates

Theoretically, transmission electron microscopy (TEM) is compatible with three different types of phase plate: thin-film, electrostatic, and magnetic. However, designing functional phase plates has been an arduous process that has suffered from unavoidable technical obstacles such as phase-plate charging and difficulties associated with micro-fabrication of electrostatic and magnetic phase plates. This review discusses phase-contrast schemes that allow visualization of transparent objects with high contrast. Next it deals with recent studies on biological applications ranging from proteins and viruses to whole cells. Finally, future prospects for overcoming the problem of phase-plate charging and for designing the next generation of phase-plates to solve the problem of electron loss inherent in thin-film phase plates are discussed.

Electrostatic potential imaging of phase-separated structures in organic materials via differential phase contrast scanning transmission electron microscopy

Microscopy ◽  
2020 ◽  
Vol 69 (5) ◽  
pp. 304-311
Author(s):  
Shin Inamoto ◽  
Satoru Shimomura ◽  
Yuji Otsuka
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electrostatic Potential ◽  
Scanning Transmission Electron Microscopy ◽  
Phase Contrast ◽  
Organic Materials ◽  
Differential Phase ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Differential Phase Contrast

Abstract Electron staining is generally performed prior to observing organic materials via transmission electron microscopy (TEM) to enhance image contrast. However, electron staining can deteriorate organic materials. Here, we demonstrate electrostatic potential imaging of organic materials via differential phase contrast (DPC) scanning transmission electron microscopy (STEM) without electron staining. Electrostatic potential imaging drastically increases the contrast between different materials. Phase-separated structures in a poly (3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blend that are impossible to observe using conventional STEM are clearly visualized. Furthermore, annealing behavior of the phase-separated structures is directly observed. The morphological transformations in the samples are consistent with their physical parameters, including their glass transition and melting temperatures. Our results indicate that electrostatic potential imaging is highly effective for observing organic materials.

Quantitative Investigations of Interfaces and Grain Boundaries by Phase Contrast Electron Microscopy with Ultra High Resolution

2001 ◽  
Vol 7 (S2) ◽  
pp. 288-289
Author(s):  
C. Kisielowski ◽  
J.M. Plitzko ◽  
S. Lartigue ◽  
T. Radetic ◽  
U. Dahmen
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Phase Contrast ◽  
Recent Progress ◽  
Image Interpretation ◽  
Present Contribution ◽  
Crystalline Materials ◽  
Transmission Electron ◽  
Contrast Microscopy ◽  
Lattice Images

Recent progress in High Resolution Transmission Electron Microscopy makes it possible to investigate crystalline materials by phase contrast microscopy with a resolution close to the 80 pm information limit of a 300 kV field emission microscope'"". A reconstruction of the electron exit wave from a focal series of lattice images converts the recorded information into interpretable resolution. The present contribution illustrates some recent applications of this technique to interfaces.Fig. 1 shows a reconstructed electron exit wave of a heterophase interface between GaN and sapphire. The experiment takes advantage of three factors: First, we resolved the GaN lattice in projection, which requires at least 0.15 nm resolution. The projection eliminates the stacking fault contrast that usually obscures lattice images in the commonly recorded projection. Thus, image interpretation is drastically simplified. Second, all atom columns at the interface and in the sapphire are resolvable with a smallest projected aluminum - oxygen spacing of 85 pm in the sapphire.

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