On Fri, 12 Feb 1999 sknauer@nexstar.com wrote:

> Does anyone know of a reliable fat stain that will intensely stain saturated
> fatty acids?   Most stains that I've come across rely on unsaturated
>(C=C) bonds
> to work.

  Fatty acids (regardless of the amount of unsaturation) can be
  stained with Cain's nile blue method or Holczinger's
  copper-dithiooxamide method. These are in the standard techniques
  books. If you want to use a solvent dye (sudan black, oil red O
  etc) you have to use it at a higher than usual temperature
  (try 60 C) so that the saturated lipids will be in the liquid
  state. This is necessary for the dye molecules to pass from
  the solvent into the lipid droplets. I don't think there is
  any way to stain saturated but not unsaturated fat/fatty acids.
  A good reference is Bayliss High, O. 1984. Lipid Histochemistry
  (Royal Microscopical Society Handbooks 06). Oxford: Oxford
  Univ. Press. 68 pages. Good value for money (9 pounds) if you
  don't want to splash out on one of the bigger histol/histochem
  techniques books. You can read about it on the RMS web site:
  www.rms.org.uk/hbdetail.htm  and order it from the Society's
  present publisher, BIOS  www.bios.co.uk

 John A. Kiernan,
 Department of Anatomy & Cell Biology,
 The University of Western Ontario,
 LONDON,  Canada  N6A 5C1