Wellcome has awarded their prizes for best scientific images of the year, and they are pretty.
This micrograph, taken with a laser scanning confocal microscope (see post below,) is a picture of colon cancer cells. The fluors used are not labelled, but I shall make some educated guesses.
Blue here is a nuclear stain, meaning that it stains DNA in the nucleus of the cell, such as DAPI or BOBO.
The green fluor is a cytoskeleton stain. The cytoskeleton component stained here appears to be filamentous actin, because I see some stress fibers through the cells. The stain is probably phalloidin (a toxin from death cap mushrooms) conjugated to a fluor.
The red color is more ambiguous. It seems to colocalize with the cytoskeleton in some cells (red + green = yellow) but is more diffused and cytoplasmic in others. Could be an actin binding-protein or another component of the cytoskeleton.