Labeling of living cells

So MK, Yao HQ, Rao JH (2008) HaloTag protein-mediated specific labeling of living cells with quantum dots. Biochem Biophys Res Commun 374 419-423... 

Poloukthine AA, Mbua NE, Wolfert MA et al (2009) Selective labeling of living cells by a photo-triggered click reaction. J Am Chem Soc 131 15770-15776... 

Fluorescence Labeling of Living Cell Surfaces by Azaelectrocyclization... 218... 

Intracellular labeling of live cells Calcein AM The enzymatic (intracellular esterase) conversion of the nonfluorescent Fluorescence... 

Selective Labeling of Living Cells by a Photo-Triggered Click Reaction... 

A dual isotope labeling technique [85] has been used to measure membrane permeability in plant cells, based on the selective permeabiHty of the membranes of living cells to tritiated water and carbon-14 labeled mannitol. Kieran [29] showed that the results of the dual isotope labeling and Evan s Blue staining methods correlated well as indicators of cell viability however, the latter was preferable in terms of reagent cost and ease of analysis. 

Some workers have used spin labels attached to a membrane or biological macromolecule to study the motion of these components of living cells (Chapter 5). 

Bark, S. J. and Hahn, K. M. (2000). Fluorescent indicators of peptide cleavage in the trafficking compartments of living cells Peptides site-specifically labeled with two dyes. Methods 20, 429-435. 

There have been rather few studies of the location of probes in whole cells. DPH incorporates into most subcellular fractions (see, e.g, Ref. 64), whereas with TMA-DPH, early after introduction only the plasma membranes appear to be labeled/64,65) There is considerable interest in examining the lipid motional properties of living cells by fluorescence techniques. In this type of study the location of the probe has to be carefully checked before conclusions can be drawn. This is carried out by separate measurements of the recovery of probe from intact labeled cells in isolated subcellular fractions and/or by fluorescence microscopy. 

Eakin, R.T., Morgan, L.O., Gregg, C.T., Matwiyoff, N.A. (1972). Carbon-13 nuclear magnetic resonance spectroscopy of living cells and their metabolism of a specifically labeled 13C substrate. FEBS Lett. 28,259-264. 

Green fluorescent protein (GFP) and related fluorescent proteins can be used to label practically any protein or subcellular compartment of living cells (49). Transfection of cells with plasmids that encode appropriately targeted fluorescent fusion proteins has been used to define the plasma membrane, early endosomes, late endosomes, caveolae, the golgi complex, the ER, and other subcellular locations. Several fluorescent small molecules are also available for labehng specific cellular organelles, including endosomes and lysosomes, for analysis by fluorescence microscopy. 

Fluorescence microscopy is one of the most powerful imaging methods in modern biomedical research. Noninvasive, fluorescence microscopy allows dynamic imaging of live cells, tissues, and whole organisms. This capability for live sample imaging, combined with a large repertoire of spectrally distinct fluorescent probes and a variety of biochemically specific labeling techniques, enables the direct visualization of complex molecular and cellular processes in real time under physiological conditions. 

Wang, Y.-l. and Taylor, D.L. (1989a). Fluorescence Microscopy of Living Cells in Culture. Part A Fluorescent Analogs, Labeling Cells, and Basic Microscopy. Academic Press, New York. 

However, affinity, photochemical, or radioisotope tags can also be used. After removal of unbound molecules in solution, the microarrays are subject to detection to determine the binding of target molecules, or the target molecule-induced alteration of live cells in the microarrays. These interactions are usually detected and quantified by the fluorescence of fiuorophore-labeled target molecules. Fluorescent detection is sensitive, can have high resolution, and is compatible with many fluorescence-based microarray scanners. 

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