The ultrastructure of the ocular pigment abnormality of human Chédiak-Higashi syndrome is described. The presence of giant abnormal melanosomes, probably the end result of the fusion of smaller abnormal organelles, was the most striking pathologic finding. This defect involved both optic cup and neural crest-derived melanocytes; the former were affected more severely. Giant lysosome-like organe...

Archaeopteryx has been regarded as an icon of evolution ever since its discovery from the Late Jurassic limestone deposits of Solnhofen, Germany in 1861. Here we report the first evidence of colour from Archaeopteryx based on fossilized colour-imparting melanosomes discovered in this isolated feather specimen. Using a phylogenetically diverse database of extant bird feathers, statistical analys...

A primary role of melanin in skin is the prevention of UV-induced nuclear DNA damage to human skin cells, where it serves to screen out harmful UV radiation. Melanin is delivered to keratinocytes in the skin after being excreted as melanosomes from melanocytes. Defects in melanin production in humans can cause diseases, many of which currently lack effective treatments due to their genetic orig...

Melanin is responsible for pigmentation of skin and hair and is synthesized in a specialized organelle, the melanosome, in melanocytes. A genome-wide association study revealed that the two pore segment channel 2 (TPCN2) gene is strongly linked to pigmentation variations. TPCN2 encodes the two-pore channel 2 (TPC2) protein, a cation channel. Nevertheless, how TPC2 regulates pigmentation remains...

Oxygen isotope ratios and rare earth element (REE) concentrations provide independent tests of competing models of injection v. anatexis for the origin of migmatites from amphibolite and granulite facies metasedimentary rocks of the Adirondack Mountains, New York. Values of dO and REE profiles were measured by ion microprobe in garnet–zircon pairs from 10 sample localities. Prior U–Pb SIMS dati...

Chicken embryo retinal pigment cells provide an excellent opportunity for studying a number of aspects of cell growth and synthesis of a differentiative cellular product. These cells can be removed from the eyes of chicken embryos virtually uncontaminated by other cell types, satisfactorily maintained in cell culture and produce a highly specific, morphologically and biochemically identifiable ...

The activity of tyrosinase (EC 1.10.3,1 o-diphenol:02 oxidoreductase) was found to be in melanosomes, smooth-surface membranes, rough-surface membranes , and ribosomes when they are isolated from Harding-Passey mouse mela-noma. In vivo incorporation studies of 14C-dopa into these cell particles were carried out in order to clarify the site of malanin formation in melanocytes. '4C-dopa incorpora...