Cryo-electron microscop

Menetret J-F, Hofmann W, Schroder R R, Rapp G and Goody R S 1991 Time-resolved cryo-electron microscopic study of the dissociation of actomyosin Induced by photolysis of photolablle nucleotides J. Mol. Biol. 219 139-43... 

Figure 8 Paclitaxel encapsulated into DQAsomes. (A) Transmission electron microscopic image (uranyl acetate staining). (B) Size distribution. (C) Cryo-electron microscopic image. Source-. From Ref. 43.

Figure 29-4 Structure of 23S-28S ribosomal RNAs. (A) The three-dimensional structure of RNA from the 50S subunit of ribosomes of Halocirculci marismortui. Both the 5S RNA and the six structural domains of the 23S RNA are labeled. Also shown is the backbone structure of protein LI. From Ban et al.17 Courtesy of Thomas A. Steitz. (B) The corresponding structure of the 23S RNA from Thermus thermophilus. Courtesy of Yusupov et al.33a (C) Simplified drawing of the secondary structure of E. coli 23S RNA showing the six domains. The peptidyltransferase loop (see also Fig. 29-14) is labeled. This diagram is customarily presented in two halves, which are here connected by dashed lines. Stem-loop 1, which contains both residues 1 and 2000, is often shown in both halves but here only once. From Merryman et al.78 Similar diagrams for Haloarcula marismortui17 and for the mouse79 reveal a largely conserved structure with nearly identical active sites. (D) Cryo-electron microscopic (Cryo-EM) reconstruction of a 50S subunit of a modified E. coli ribosome. The RNA has been modified genetically to have an...

Figure 6.24 EM and X-ray crystallographic images compared . Approximately 30 A resolution image of GroEL/GroES/ADPy (T state [bottom ring] R state [top ring]) within which has been incorporated the approximately 2 A resolution X-ray crystal structure of GroEE/GroES/ADPy (see Fig. 6.17 as well). The Cryo-electron microscope image has the appearance of a Van der Waals surface representation of the molecular chaperone machine (illustration adapted from Ranson et al., 2001, Fig. 7).

Cryo-electron microscopic 3D-reconstruction of an intact microtubule (Resolution ca. 0.8 nm). 

The droplet sizes of the nanoemulsions characterized by dynamic light scattering at O/S ratios between 50 0 and 70 30 and a constant water content of 90 wt% were between 200 and 220 nm, displaying a slight increase with increasing O/S ratio. Figure 6.3 shows atypical cryo-transmission electron microscope (TEM) image of an... 

Negata T. Electron microscope radioautography with cryo-fixation and dry mounting procedure. Acta Histochim Cytochem 1994 27 471 —489. 

The invention of the electron microscope in the 1930s by Knoll and Ruska cleared the way for scientists to take an even closer look at vesicles and other colloidal structures [5]. Improving the resolution of the optical microscope roughly by the factor that the optical microscope improved that of the unaided eye, the finer structures of colloidal systems became visible. With the electron microscope, single bilayers can be made visible and the distance between lamellae can be determined. Thus, the structure of a given system can be determined to up to 1/10000000 of a millimeter, which is about the distance of six atoms in a molecule. The most impressive results are obtained with the freeze fracture and cryo-TEM methods [6]. 

Electron microscopy is an efficient microscopy technique that has been extensively used for the material characterization of artistic and archaeological objects, especially in combination with x-ray microanalysis [54], The use of electrons instead of light in these instruments is the basis of the higher resolution ( 9-0.2 nm) and has greater depth of held than LM. Thus, characterization of the finest topography of the surface objects is possible, and additional analytical information can be obtained. Different electron microscopes are currently used in art and art conservation studies scanning electron microscopes (SEM), Cryo-SEM... 

Figure 31-3 (A) Cryo atomic force (AFM) micrograph of molecules of the human immunoglobulin IgM. Courtesy of Zhifeng Shao, University of Virginia. (B) Schematic diagram. One-fifth of this structure is shown in greater detail in Fig. 31-4A. (C) Model based on earlier electron microscopic images. From Feinstein and Munn. 64(2...

After quick freezing in liquid nitrogen and fracture, another etching method was used at — 90 °C for less than 1 min in a 1.33 x 10-4 Pa chamber. The etched sample was cooled to — 130°C and coated with platinum and carbon in the same vacuum chamber and transferred to the scanning electron microscope at — 130 °C. The observed structure was closer to reality than that obtained by the method previously described. This is called the cryo-SEM technique [32]. CryoSEM images are shown in Fig. 4 which presents the structural change by stretching [16]. 

Fig. 11.1. Fungal microcolonies and associated extracellular pol3uneric substances (EPS). (A) On the surface of marble in Greece (Athens). The EPS network around black fungal colonies is stained red (on the photo -light grey) by periodic acid - Schiff s reagent stain (PAS). (B) Cryo-scanning electron microscope image of a fungal microcolony with its inherent mucilage. This colony of strain A49 was cultured in subaerial conditions with some additional supply of nutrients from the substrate.

High-resolution cryo-EM data can be collected in two forms as electron images (69) or as electron diffraction patterns. Cryo-EM images contain information on both amplitude and phase, which can be analyzed after Fourier transformation. The quality of the amplitude data can be improved if combined with electron diffraction data, which contains only amplitude information. In this way, EM overcomes one of the main difficulties in XRC. In XRC, only diffraction patterns are obtained. X-rays caimot be used to form an image of the crystal therefore, the phase information is lost. In contrast, electron microscopes contain electron lenses that can capture phase information. 

Cryo-electron microscopy was performed on a JEOL JEM-3100FFC transmission electron microscope (cryo-TEM) (see Note 11). 

The prevailing knowledge on the ultrastructural pattern of pellicle formation and the micromorphological appearance of pellicle is mainly based on (conventional) transmission and scanning electron microscopic investigations [3, 17, 29, 60-67], Only a very few results have been published using novel techniques, such as cryo electron microscopy [68, 69], CLSM [28], or atomic force microscopy [19, 38, 70] for analysis of the pellicle. 

A second approach to postembedding electron microscopic immunocytochemistry is the use of special aqueous resins, while these resins are still hydrophobic, they tolerate some aqueous material in the tissue. Examples of these resins are LR White or Lowicryl K4M. Another approach with aqueous embedding is to freeze tissue in buffer very rapidly, and to section with a cryo-ultramicrotome. Cryo-ultramicrotomy is a technique requiring considerable training and cannot be used by the novice. 

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