>     Hello, could you tell me whether FM 4-64 will stain membranes of
>     prefixed material?
>
>     Thanks,
>
>     Anna Smallcombe

Depends on the fixation and whether the sample is dehydrated.  The styryl
pyridinium probes seem to need the aqueous phase in order to generate
fluorescence.  My experience has been that with aldehyde-fixed cells
(endothelial cells, some neuronal cells, transformed pulmonary eptithelial
cells) in water (or buffer) the dye is able to permeate small pores
introduced into the plasmalemma by the fixation and label the cells from the
inside.

I have not tried osmicated material and am unsure whether a "solid-state"
hydrophobic phase at the polar-nonpolar interface would allow the styryl
pyridinium an emission dipole, although singly charged styryl dyes fluoresce
when adsorbed to silica gel in water.

Good luck.

Lane Niles
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Walter D. Niles, Ph.D.
Department of Pharmacology
MSB E403  M/C 868
835 South Wolcott Avenue
University of Illinois at Chicago
Chicago, IL    60612
312-355-0236 (Voice)
312-413-0222 (Fax)
http://www.uic.edu/~wniles/