The polar lipids from keratinized tissues of some vertebrates

1. The lipids from a variety of keratinized tissues from terrestrial vertebrates were extracted with chloroform:methanol and the nonpolar and saponifiable lipids were removed. The composition of the remaining polar lipids was examined by thin layer chromatography and color reactions. 2. The tissues studied included: hair from a monkey (Macacca fascicularis), dog (Canis familiaris), raccoon (Procyon lotor) and cow (Bos taurus); full-thickness epidermis from a pig (Sus scrofa) and pilot whale (Globicephala melaena); epidermal scales and feathers from a fowl (Gallus gallus); scales, feathers, beaks and claws from a turkey (Meleagris gallopavo); hoof and horn from cattle (Bos taurus); and cast skins from a Columbian boa (Boa constrictor) and a Ball python (Python regius). 3. All of the tissues contained both simple ceramides and highly polar glycolipids (presumably gangliosides). 4. Glycolipids of intermediate polarity were present in all of the tissues from birds and snakes and in the mammalian tissues which contained unkeratinized epidermal cells, but were absent from fully keratinized mammalian tissues such as hair, hoof and horn. 5. The presence of the highly polar gangliosides provides for the formation of the multiple intercellular lipid lamellae which have been observed in the epidermal horny layer of mammals, birds and reptiles and which are believed to constitute the epidermal barrier to water diffusion.