ABSTRACT
Fluorescence microscopy is the deŽnitive technique of cell biology. The histologist uses conventional transmitted light microscopy, and the anatomist uses electron microscopy, but the cell biologist uses ªuorescence. The ability to label individual structures, molecules, or cell compartments gives us enormous power to visualize the structure and even the dynamics of the workings of cells. Immunolabeling identiŽes components with exquisite sensitivity in Žxed (and therefore dead) tissue, whereas tagging with green ªuorescent protein (GFP) and other expressible ªuorescent proteins (Chapter 12) can reveal molecular information about living cells. Fluorescent in-situ hybridization (FISH) reveals genes. Add to this the dyes such as DAPI (DNA) and rhodamine 123 (endoplasmic reticulum or ER), which target speciŽc cell structures and compartments; indicator dyes that can reveal ion concentrations and membrane potential; and the natural ªuorescence of many important cell components (NADP, chlorophyll); and the fundamental power and importance of ªuorescence microscopy are clear. Fluorescence microscopy also provides the underpinnings of more recent techniques, such as confocal and multiphoton microscopy, which now enable us to image in three dimensions, not just two.
