Foods with a relatively high biotin content include Swiss chard, raw egg yolk (however, the consumption of avidin-containing egg whites with egg yolks minimizes the effectiveness of egg yolk's biotin in one's body), liver, Saskatoon berries, and leafy green vegetables.
It has been isolated from a variety of sources including the petals and flowers of plants in the genus Physalis, orange rind, papaya, egg yolk, butter, apples, and bovine blood serum.
However, as the paint is not commercially available, the artist must mix his own colours using pigment powders, oil, varnish, egg yolk and a preservative; uniquely, Ramsay discovered that Scotch whisky is an excellent preservative for the egg in the oil tempera mix!
The first phospholipid identified as such in biological tissues was lecithin, or phosphatidylcholine, in the egg yolk, by Theodore Nicolas Gobley, a French chemist and pharmacist, in 1847.
The dorsal/ventral axis is defined in chick embryos by the orientation of the cells with respect to the yolk.
Other than sophorolipids, common biosurfactants include rhamnolipids which can be produced by some species of Pseudomonas, and Lecithin which can be obtained either from soybean or from egg yolk and is a common food ingredient.