Myxoxanthophyll Myxoxanthophyll Myxoxanthophyll is a carotenoid glycoside pigment present (usually as rhamnosides) in the photosynthetic apparatus of cyanobacteria. It is named after the word ""Myxophyceae"", a former term for cyanobacteria. As a monocyclic xanthophyll, it has a yellowish color. It is required for normal cell wall structure and thylakoid organization in the cyanobacterium "Synechocystis". The pigment is unusual because it is glycosylated on the 2'-OH rather than the 1'-OH position of the molecule. Myxoxanthophyll was first isolated from "Oscillatoria rubenscens" in 1936. The bright red pigment lycopene is the acyclic precursor of all carotenoids in cyanobacteria. In myxoxanthophyll synthesis, lycopene is
Labrador Retriever coat colour genetics the colour of the dark pigment, eumelanin, and is referred to as the B (brown) locus. The variation displayed by this locus is observed in many mammals, reflecting a so-called 'dilution', a lightening, of black eumelanin to a brown colour. Initial genetic research excluded a role for the melanocortin 1 receptor and the "Agouti" locus as being the cause of the black dilution trait in dogs. Instead, TYRP1 (tyrosine related protein 1) was found to be responsible. This enzyme is localised to melanosomes, the cellular organelles that produce and store pigments, and serves to catalyze oxidation of eumelanin precursors. In