Surface labeling

For ordered periodic structures of a period A a dimensionless ratio between the two lengths, Ryy = Kyy /, provides an additional characteristic of the structure. On the basis of the results of Ref. 39, we can estimate this ratio for the periodic minimal surfaces. For simple minimal surfaces, P, D, or G [39], we find respectively = 0.306, Ryyi = 0.195, and Ryyi = 0.248. For more complicated periodic structures [39] its value can be even smaller than 0.1 for example, for the surface labeled GX5, Ryy = 0.073. 

Figure 3. E. chrysanthemi cell surface labelling with sulfo-NHS-biotin. After labelling, the proteins were separated by SDS-PAGE, blotted onto nitrocellulose and revealed with PemB-antibodies (A) or with streptavidin-peroxidasc (B). Lane 1 A350 (wild type) lane 2 A837 kdgRy, lane 3 A350/pPME6. An arrowhead indicates the PemB position.

Figure 9.12 Binding energies of O versus d-band center (relative to the Fermi level, - sp) of the Pt and Pt3Co alloy surfaces. Labels identify the adsorption sites. The line is the best hnear fit. (Reproduced with permission from Xu et al. [2004].)...

Yu J, Choi S, Richards Cl, Antoku Y, Dickson RM (2008) Live cell surface labeling with fluorescent Ag nanocluster conjugates. Photochem Photobiol 84 1435-1439... 

Fig. 1. Flowchart of the surface labeling procedure. Abbreviations as in text.

The use of any detergent-like molecule is inappropriate for surface labeling, since it may remove portions of the surface membrane and dissolve the attachments for surface markers, as well as permeabilizing the cell to antibodies. 

The procedure given above may be used successfully to surface-label cells or tissue for examination by SEM. 

Fig. 9.8. Deflection of a bimorph. Two long, thin plates of piezoelectric material are glued together, with a metal film sandwiched in between. Two more metal films cover the outer surfaces. Both piezoelectric plates are poled along the same direction, perpendicular to the large surface, labeled z. (A) By applying a voltage, stress of opposite sign is developed in both plates, which generates a torque. (B) The bimorph flexes to generate a stress to compensate the torque. The neutral plane, where the stress is zero, lies at hi i from the central plane.

In order to derive the relation between EMF and the chemical potential difference probed at different surfaces of the stressed solid, we formulate the reversible work and its electrical equivalent. If zAF-dnA electric charges are transported across the electrolyte between the two surfaces labeled 1 and 2 in Figure 8-8, the electrical work is... 

Tolsen, N. D., Boothroyd, B., and Hopkins, C. R. (1981) Cell-surface labelling with gold colloidal particles, the use of avidin and staphylococcal protein A-coated gold in conjunction with biotin and Fc-beanng ligands. J. Microsc 123,215—226. 

A number of similar studies on cell surface galactolipids have been based on this galactose oxidase-NaB3Hi, reduction procedure. However, it is now apparent that only a very small portion, less than 0.5% if any, of the cerebrosides in membranes are oxidizable by galactose oxidase. Therefore, cerebrosides and possibly other galactolipids previously identified by the surface labeling... 

When HeLa cells were.cultured in medium supplemented with 5 mM sodium butyrate, their content of GM3 increased (Fig.2a). Increases varied from 3.5 to 5-fold depending on the experiment (4,8,12,13). When the butyrate was removed and the cells were cultured in normal medium for 24 h, the GM3 levels returned to those found in untreated cells (Fig. 2a). Similar results were observed when N-[acetyl-3H]-D-mannosamine, a precursor of sialic acid, was also included in the culture medium. In the butyrate-treated cells, radioactivity associated with GM3 increased 6.5-fold and 24 h after butyrate was removed, the amount of labeling returned to control values (Fig. 2b). We also were able to label the GM3 by means of a cell surface labeling technique. Control and butyrate-treated cells were exposed to 10 mM sodium periodate and the oxidized sialyl residues were reduced with NaBSfy. There was 5.5-fold more 3h associated with the GM3 recovered from the butyrate-... 

Cut out all four pictures and use rubber cement to mount them on posterboard or some other heavy mounting surface. Label the first drawing Realistic. Label each subsequent drawing with the name of the movement represented. 

In another case in which a number of exemplary control experiments were done, Markwell and Fox (1980) crosslinked the outer membranes of enveloped viruses with methyl 3-(p-azidophenyl)dithio]propionimidate. Virus (4 mg protein/ml) was reacted with the imidate (0.1 to 0.5 mM) at 0°C for 30 min at pH 8.5. The reaction was quenched with 50 mM ammonium acetate, 50 mM NEM (30 min, 25 °C), and the vims recovered by centrifugation. After irradiation the crosslinked polypeptides were examined in a two-dimensional SDS-polyacrylamide gel. One complication was that the crosslinking pattern had to be compared with a native pattern of disulfide linkages, and a reagent with a different cleavable crosslink may have been a better choice. As mentioned above, the analysis was simplified by the use of surface labeling. 

In recent years there has been considerable interest in the structure of biological membranes, and photochemical reagents capable of yielding low resolution structural information about membrane proteins have been developed. Several examples of photochemical surface-labeling reagents have appeared, and much effort has been devoted to the development of photoactivatable hydrophobic reagents for labeling from within the lipid bilayer. 

Photochemical surface labeling reagents introduced by Staros and Richards (1974) have a number of potential advantages. First, the high... 

A macromolecular, photochemical surface labeling reagent was developed by Louvard et al. (1976). It comprised a Fab fragment of a human myeloma protein with which 4-fluoro-3-nitrophenylazide (Table 5.1.1c) had been reacted. Used at a concentration of 0.1 mM, this conjugate could be used to label the surfaces of sealed vesicles or it could be trapped inside vesicles and used to label from within. Louvard and colleagues focused their attention on the modification of aminopeptidase in intact brush-border membranes and demonstrated that the enzyme spans the bilayer. From the... 

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