1. Carotenoids have been identified and their quantities measured in the eyes of several frog species. The combined pigment epithelium and choroid layer of an R. pipiens or esculenta eye contain about 1gamma of xanthophyll and about 4gamma of vitamin A. During light adaptation the xanthophyll content falls 10 to 20 per cent. 2. Light adapted retinas contain about 0.2-0.3 gamma of vitamin A alon...

The purple membrane ofHalobacterium halobium contains a single protein known as bacteriorhodopsin, which is composed of 1 mol retinal]mol bacterio-opsin [ 1 ]. The organization of the protein within each purple membrane sheet is that of an exact 2-dimensional crystal. X-ray and electron diffraction data have revealed that the bacteriorhodopsin in purple membrane is arranged as trimeric units in...

The purple leaf pigmentation mainly associated with anthocyanins accumulation is common in Brassica but the mechanisms of its production and its potential physiological functions are poorly understood. Here, we performed the phenotypic, cytological, physiological, and comparative leaves transcriptome analyses of 11 different varieties belonging to five Brassica species with purple or green leav...

Field assays were performed to determine the optimal color for Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) traps. Previous studies have found that more A. planipennis are caught on purple or green traps than traps of other colors. In three studies, we evaluated various shades of purple, wavelengths of green (500-570 nm), and greens of different reflectance (from 9 to 66%). In all te...

The classical absorption spectrum of visual purple (KSttgen and Abelsdorff, 1896) is the difference in photometric density (log Io/I) at different wave-lengths between a solution in its unbleached and its bleached condition. The reason for this procedure is that extracts of visual purple are not pure but contain other substances which may be colored. The resulting classical subtraction curve is...

The filamentous green alga Zygogonium ericetorum (Zygnematophyceae, Streptophyta) was collected in a high-alpine rivulet in Tyrol, Austria. Two different morphotypes of this alga were found: a purple morph with a visible purple vacuolar content and a green morph lacking this coloration. These morphotypes were compared with respect to their secondary metabolites, ultrastructure, and ecophysiolog...

It is now well established that vision in dim light is due to the photochemical decomposition of “visual purple,” a pigment present in the rods of the retina (1). Visual purple is believed to be a conjugated protein in which vitamin A or one of its derivatives is a prosthetic group (2). As might be expected, the spectral sensitivity curve of the eye parallels the absorption spectrum of visual p...

The dogwhelk Nucella lapillus is a rocky intertidal gastropod of the North Atlantic coast. Individual shell color varies. Common colors range between white and brown, with darker dogwhelks being more affected by heat stress than lighter-colored conspecifics. Other reported shell colors are black, mauve, pink, yellow, and orange from European coasts, red and grey from the Bay of Fundy coast of N...

Changes effected in purple uteroferrin’s resonance Raman spectrum by mercaptoethanol reduction suggest that the protein’s single iron atom is coordinated to more than one tyrosyl residue. Detection of a conservative pair of visible CD bands, indicative of exciton splitting of a tyrosinate-to-iron charge transfer band, strongly supports this suggestion. Additional features in the protein’s visib...