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...

Vitamin A (VA) deficiency is a worldwide public health problem. Biofortifying existing sources of b-carotene (bC) and increasing dietary bC could help combat the issue. Two studies were performed to investigate the relative bC bioavailability of a bC supplement to purple, high-bC orange, and typical orange carrots using Mongolian gerbils (Meriones unguiculatus). In study 1, which used a traditi...

Purple rice is a strain of glutaneous rice rich in anthocyanins and γ-oryzanol. Both types of compounds are involved in antioxidant and lipid metabolism of mammals. Three experimental diet types were used which consisted approximately by half either of purple rice, white rice or corn. Diets were fed to 3×10 pigs growing from about 30 to 100 kg. Meat samples were investigated either as raw or cu...

Purple urine bag syndrome (PUBS) is an infrequent condition, seen mostly in elderly female patients, characterized by an intense purple discoloration of contents of urine bag following long-term indwelling urinary catheterization. The purple discoloration is most often due to the presence of indigo and indirubin pigments which are metabolites of tryptophan. Urinary bacteria with indoxyl sulphat...

Although anoxygenic photosynthesis is thought to play an important role in the primary productivity of permanently frozen lakes in the Antarctic dry valleys, the bacterial communities responsible for this metabolism remain uncharacterized. Here we report the composition and activity of phototrophic purple bacteria in Lake Fryxell, Antarctica, as determined by analysis of a photosynthesis-specif...