Visualization by electron

Crawford AR, Smith AJ, Hatch VC, Oude Elferink RP, Borst P, Crawford JM. Hepatic secretion of phospholipid vesicles in the mouse critically depends on mdr2 or MDR3 P-glycoprotein expression. Visualization by electron microscopy. J Clin Invest 1997 100(10) 2562-2567. 

Iodoacetyl-LC-biotin has been used to localize the SH thiol of myosin by use of an avidin-biotin complex visualized by electron microscopy (Sutoh et al., 1984) and to determine the spatial relationship between SHj and the actin binding site on the myosin subfragment-1 surface (Yamamoto et al., 1984). 

Subsequent to possible solubilization of membrane-bound proteins, solubilization must be verified. The criteria listed in Table 2 are relevant in assessing whether solubilization has been accomplished. To ascertain whether the solubilized protein has retained biological activity, membrane reconstitution (28) is attempted subsequent to detergent removal (24). Reconstitution is often visualized by electron microscopy employing either negative staining or freeze fracture. 

Schultz P, Olland S, Oudet P, Hancock R. Structure and conformational changes of DNA topoisomerase II visualized by electron microscopy. Proc Natl Acad Sci USA 1996 93 5936-5940. 

CNTs are also valuable as field emitters because they have a small virtual source size [30], a high brightness, and a small positive temperature coefficient of resistance [31]. The latter means that they can run hot under high emission currents, but not go into thermal runaway. Emission from nanotubes can be visualized by electron holography in a TEM [32],... 

B. Effect of the ionic strength on hyperacetylated 208-12 nucleosome arrays as visualized by electron microscopy. The numbers to the left indicate the milimolar NaCl concentration [369]. [Reproduced from Garcia-Ramirez M. et al. (1995) J. Biol. Chem. 270, 17923-17928, with permission from The American Society for Biochemistry and Molecular Biology.]... 

Apolipoproteins ( apo designates the protein in its lipid-free form) combine with lipids to form several classes of lipoprotein particles, spherical complexes with hydrophobic lipids in the core and hydrophilic amino acid side chains at the surface (Fig. 21-39a). Different combinations of lipids and proteins produce particles of different densities, ranging from chylomicrons to high-density lipoproteins. These particles can be separated by ultracentrifugation (Table 21-2) and visualized by electron microscopy (Fig. 21-39b). 

The acetylcholine receptor has four subunits (a, /3, y, and 5, with Mr 52, 56, 63, and 66 x 103, respectively). The complete receptor includes two copies of the a subunit, and one of each of the others. The overall structure, as visualized by electron microscopy, resembles a cylindrical bundle of five, approximately parallel rods, with a water-filled channel along the axis of the cylinder (fig. SI. 12). This assembly projects about 70 A into the synaptic cleft on one side of the membrane and about 40 A into the intracellular... 

When microtubules were visualized by electron microscopy (EM), after the improvement of methods of fixation, it was realized that they formed the structural basis of flagellar axonemes and of so-called spindle fibers, as well as occurring as individual filaments in the cytoplasm. Their designation as part of the cytoskeleton suggested that they acted mainly as fixed structural supports. Subsequent research has focused more and more on their dynamic behavior and on their role as tracks for motor proteins, which may, for example, transport chromosomes during cell division. Microtubules are found in all eukaryotic cells and are essential for many cellular functions, such as motility, morphogenesis, intracellular transport, and cell division. It is that dynamic behavior that allows microtubules to fulfill all of these functions in specific places and at appropriate times in the cell cycle. 

Coskun, U., Chaban, Y. L., Lingl, A., Muller, V., Keegstra, W., Boekema, E. J., and Gruber, G. (2004a). Structure and subunit arrangement of the A-type ATP synthase complex from the archaeon Methanococcus jannaschii visualized by electron microscopy./. Biol. Chem. 279, 38644-38648. 

Radermacher, M., Ruiz, T., Harvey, W. R., Wieczorek, H., and Gruber, G. (1999). Molecular architecture of Manduca sexta midgut Vi ATPase visualized by electron microscopy. FEBS Lett. 453, 383-386. 

Immunoelectron microscopy (IEM) is the term generally used for techniques that detect the specific binding of antibody to antigen that can be visualized by electron microscopy (1). The use of these techniques results in a 2- to 10,000-fold increase in particle numbers in comparison with methods not using antisera (1) and allows the transmission electron microscope (TEM) to become a sensitive tool, which the plant virus diagnostician or researcher can use to... 

Collagen IV molecules have been visualized by electron microscopy after spreading on cleaved mica and rotary shadowing (Oberbaumer et al., 1982 Bachinger et al., 1982). A typical molecule appears as a long strand terminating in a distinct globule (Fig. 3a). Several major domains (Fig. 5) have been defined in the molecule. These include NCI, a terminal... 

To be spreadable, butter should possess an SFC between 20 and 40% (deMan, 1962) and have an apparent yield value (determined according to IDF, 1980) of 30-60 kPa (Rohm and Raaber, 1991). According to Figure 7.1, milk fat has an SFC between 20 and 40% at a temperature between 11 and 20°C. More homogeneous butter structures, as visualized by electron microscopy, have also been correlated with a firmer consistency (Precht and Buchheim, 1979, 1980). 

Earnshaw, W. C., King,J., and Eiserling, F. A. (1978a). The size of the bacteriophage T4 head in solution with comments about the dimension of virus particles as visualized by electron microscopy./. Mol Biol 122, 247-253. 

Yeager, M., Weiner, S., and Coombs, K. M. (1996). Transcriptionally active reovirus core particle visualized by electron cryo-microscopy and image reconstruction. Biophys.J. 70,A116. 

Animal FASs are functional dimers [76]. While /3-ketoacyl synthase requires dimer formation for activity [77], catalysis of the remaining FAS reactions is carried out by the monomeric enzyme. This behavior is reminiscent of yeast fatty acid synthase, where the -ketoacyl synthase and ACP from different subunits also contribute to the same active site. Electron microscopy and small angle scattering experiments have further defined the structure of the functional complex [34,78]. The overall shape of the molecule, as visualized by electron microscopy, is two side by side cylinders with dimensions of 160x146 x 73 A [34]. 

Although most strains of NH3-oxidizing and N02 -oxidizing bacteria have characteristic intracytoplasmic membrane structures, which can be visualized by electron microsocopy, it is not possible to distinguish the otherwise nondescript cells from other bacteria and archaea in water samples using standard microscopic techniques for ceU enumeration, e.g., epifluorescence microscopy with DNA fluorochromes. 

Shioda et al. [43,44] visualized by electron microscopy both regions of naked DNA and of DNA covered with particles in the chromosome of Halobacterium salinarium isolated from gently lysed cells. In a control experiment, they did not detect such particles in E. coli. They also reported the existence of nucleosome-like structures in S. acidocaldarius and methanogens (unpublished results cited in ref. [43]). The size of the particles detected in H. salinarium (9.5 nm) is similar to that of eukaryotic nucleosomes (10.3 nm) however, this putative archaebacterial chromatin is not as regular as eukaryotic chromatin, since not all of the DNA is covered with nucleosomes and since the length of the DNA spacer between the particles is not uniform. In contrast to these results, Bohrmann and coworkers [45] did not visualize nucleosome-like structures in isolated chromosome fibers of Thermoplasma acidophilum. These authors also reported that in situ the nucleoid of T. acidophilum appears to be highly dispersed in the cytoplasm. 

Isolation in cell culture and direct visualization by electron microscopy, followed by immunological identification using immunohistochemical techniques, may help if the identity of the VHP agent is unknown. In addition, immunohistochemical techniques, using formalin-fixed tissues, can retrospectively identify specific viral antigens using batteries of specific immune sera and monoclonal antibodies (48). 

Kondo A, Muranaka Y, Ohta I, Kanno T. Dynamic reaction in a homogeneous HDL-cholesterol assay visualized by electron microscopy. Clin Chem 1999 45 1974-80. 

When visualized by electron microscopy, complexes between T4 topoisomerase and DNA appear as particles of heterogeneous size (21-30 nm in diameter), somewhat larger than the enzyme in the absence of DNA (15 nm Kreuzer and Huang, 1983). In complexes with closed-circular DNA, enzyme molecules are found exclusively at the intersection of DNA strands, forming looped structures with the enzyme located... 

EP Gogol, U Lcken and RA Capaldi (1987) The stalk connecting the F and Fq domains of ATP synthase visualized by electron microscopy of unstained specimens. FEBS Lett 219 274-278 B Bttcher, U Lcken and P Grber (1995) The structure of the H -ATPase from chloroplasts by electron... 

Transcription of rRNA and its assembly into precursor-ribosomes can be visualized by electron microscopy. The structures resemble Christmas trees the trunk is the rDNA and each branch is a pre-rRNA transcript. Transcription starts at the top of the tree, where the shortest transcripts can be seen, and progresses down the rDNA to the end of the gene. The terminal knobs visible at the end of some pre-rRNA transcripts likely correspond to the SSU processome. a large ribonucleoprotein required for processing the pre-rRNA. 

Fimbrial adhesins may be visualized by electron microscopy. However, the processing for analysis by electron microscopy might cause alterations of the specimens, e.g. by dehydration. This might result in the collapse of certain fimbriae. Therefore, despite no fimbriae are visible by electron microscopy the afimbrial adhesins of the Dr family, e.g. AfaE of diarrheagenic and uropathogenic E. coli in fact assemble... 

Specific substrates bound to Clp ATPases have been visualized by electron microscopy. ClpAP and ClpXP bind RepA and XO, respectively, at... 

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