Immunogold techniques

Gold labeling may be used in the recently introduced catalyzed reporter deposition-immunogold technique where biotinylated tyramide molecules are attached the antibody-antigen complex site the biotinylated sites are visualized by interaction with streptavidin-gold (46,47). 

Fig. 14. Localization of PhoE-LacZ hybrid proteins in Escherichia coli by means of cell fractionation studies (A) showing clearly the presence of the hybrid protein in the total cellular proteins of induced cells (lane e), the cell envelopes of induced cells (lane f) and the Triton X-100 insoluble protein fraction of the cell envelopes (lane h) and with the immunogold technique on ultrathin cryosections an accumulation of hybrid protein in the cytoplasm is clearly shown (B). Bar = 0.2 jam. From [165],...

Fig. 15. Schematic representation of two immunogold techniques in combination with cryofracturing. A. Freeze-etch labelling in which labelled cells are fractured, etched, replicated and cleaned on acid. B. Label-fracture in which labelled cells are fractured, replicated and cleaned on water. Intramembranous particles (IMPs) are seen in projection with gold particles.

Goode NP, Shires M, Crellin DM, et al. Post-embedding double-labeling of antigen-retrieved ultrathin sections using a silver enhancement-controlled sequential immunogold (SECSI) technique. J. Histochem. Cytochem. 2004 52 141-144. 

In addition to fluorescence methods, another study [27] developed a method to permit electron microscopic localization of Ras anchor domains on cytoplasmic membrane surfaces by immunogold labeling. The particle neighbor distances can be analyzed to obtain information about possible domain structure. Expressing H-Ras and K-Ras in baby hamster kidney cells, a nonrandom particle distribution was obtained from which the estimated mean raft size was 7.5-22 nm and about 35% of the membrane area consists of rafts. The same technique applied to cells that had been incubated with [3-cydodextrin to reduce cholesterol produced completely random distributions of H-Ras. This cholesterol dependence suggests some type of coupling of rafts across the inner and outer membrane leaflets. 

Hyatt AD. Immunogold labeling techniques, in Electron Microscopy in Biology— A Practical Approach (Harris JR, ed.), IRL Press, Oxford, UK, 1991, pp. 59-81. 

APES may interfere with silver salt solutions in intensification steps of immunogold silver-staining techniques therefore, for those applications, poly-L-lysine or gelatin-coated slides are preferable. 

Holgate, C. S., Jackson, P., Lauder, I., Cowen, P N., and Bird, C. C. (1983) Surface membrane staining of immunoglobulins in paraffin sections of non-Hodgkins lymphomas using the immunogold-silver technique. J Clin. Pathol 36,742-746... 

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