Xanthommatin is the primary ommochrome eye pigment in mosquitoes. The terminal step in xanthommatin biosynthesis, involving oxidation of 3-hydroxykynurenine (3HK), can proceed enzymatically by phenoxazinone synthase or by nonenzymatic auto-oxidation of 3HK. The relative contributions of these pathways, however, are unclear. We isolated a novel Culex pipiens mutant (crimson) that could be used t...

By comparing the published DNA sequences for (a) the genes encoding the human visual color pigments (red, green, and blue) with (b) the genes encoding human, bovine, and Drosophila rhodopsins, a phylogenetic tree for the mammalian pigment genes has been constructed. This evolutionary tree shows that the common ancestor of the visual color pigment genes diverged first from that of the rhodopsin ...

Bacillus megaterium QM B1551 spores contained a unique red pigment in their membranes that was not found in other species. This red pigment, presumably a carotenoid, was synthesized about the time of dipicolinic acid synthesis during sporulation and was associated with the forespores. A yellow pigment was synthesized during sporulation in rich medium and was found in the mother cell compartment...

A novel, simple and inexpensive modification method using TEOS to increase the UV light, pH and temperature stability of a red-beet-pigment extracted from Beta vulgaris has been proposed. The effects on the molecular structure of betalains were studied by FTIR spectroscopy. The presence of betacyanin was verified by UV-Vis spectroscopy and its degradation in modified red-beet-pigment was evalua...

Prodigiosin is the only pigment of Serratia that has been subjected to chemical analysis.2' 3 The absorption spectrum of prodigiosin as isolated by Wrede has been presented by Ehrismann and Noethling.4 It has been claimed" that the chemically prepared pigment from the ether extract as obtained by Wrede can be further resolved into two components by column chromatography. The absorption spectrum...

Broiler carcass skin color is important in the USA and Mexico. Because pigments are expensive, this study evaluated the use of natural and synthetic pigments in broiler diets at commercial levels. In two trials, 280 chicks were randomly distributed (20 birds each) into seven treatments according to the pigment class (natural or synthetic) and the inclusion level (ppm of pigments) of yellow (apo...

This study examines the mechanism of mutually exclusive expression of the human X-linked red and green visual pigment genes in their respective cone photoreceptors by asking whether this expression pattern can be produced in a mammal that normally carries only a single X-linked visual pigment gene. To address this question, we generated transgenic mice that carry a single copy of a minimal huma...

among the ways of pigment production, microbial synthesis has gained more interest for high growth rate, easy extraction and high yield. pigments are used in the food industry as natural colorants and preservatives; they also have pharmaceutical applications. in this study, fungus monascus purpureus ptcc 5303 was used to produce red, orange and yellow pigments. at first, significant variables w...

Figure 1. Spectral filtering of Habronattus pyrrithrix photoreceptors. (A) Courtship display of male H. pyrrithrix (photo: Colin Hutton). (B) Boomerang-shaped retinas superimposed on principal eye lenses, small red area indicates filter position. (C) Red filter pigment visible in unstained coronal cryosection (14 μm thick) of the principal retina. (D) Tiered retina structure in thin horizontal ...

It has usually been assumed that bile pigment in the mammal is derived exclusively, or very nearly so, from the hemoglobin of mature, circulating red blood cells. Studies in the dog have revealed a close correspondence between the measurements of bile pigment excretion and the calculated degradation of hemoglobin of circulating red cells (3). A review of other studies in man, however, reveals l...