The effect of the UV-absorbing sensitizing pigment of fly photoreceptors on absolute, spectral and angular sensitivity was investigated with a wave-optics model for the facet lens-rhabdomere system. When sky light was used as a UV-rich light source, one sensitizing pigment molecule per rhodopsin increased the photoreceptor absorption by 14-18% with respect to pure rhodopsin, whilst two sensitiz...

Light-induced pigment destruction was studied in ripening apple (Malus domestica Borkh., cv. Antonovka) fruits with reflectance spectroscopy. The reflectance spectral changes attributable to light-induced transformation of xanthophyll cycle carotenoids (Car) preceded the pigment degradation. In green fruits, the destruction of chlorophyll and Car proceeded synchronously up to complete disappear...

The existence of a variety of Pseudomonas aereginosa that produced a melaninlike pigment was first reported by Radais (Compt. rend. soc. biol. 49:808, 1897) and confirmed by Gessard (Ann. inst. Pasteur 15:817, 1901). A strain of nonmotile gram-negative bacillus (1184) was isolated in this laboratory from the urine of a man with chronic pyelonephritis. The organism l)roduced a melaninlike pigmen...

The molecular phylogenetic tree of vertebrate visual pigments, constructed on the basis of amino acid sequence identity, suggests that the visual pigments can be classified into five groups (L, ML, MS, S and Rh) and that their genes have evolved along these five gene lines. Goldfish has a UV-sensitive visual pigment (S group) localized in miniature single cone cells. Medaka has one type of rod ...

A classical theory held that deuteranomaly was caused by the replacement of the normal M cone pigment by an anomalous M pigment, which was spectrally red-shifted. Two assumptions associated with that theory were: (1) that there was a single, fixed L pigment, shared by deuteranomals and normals; (2) and that everyone had two genes for cone pigments on the X-chromosome. Those two assumptions are ...

The influence of polymeric dispersants containing different functional groups on TiO2 pigment particle suspension was investigated at pH 6.0 and 9.5, using rheology and particle size data. The dispersants chosen were polyacrylic acid and modified polyacrylamides including homo and copolymers modified with carboxylate and/or hydroxyl groups. The pigment suspension was strongly affected by both p...

How melanoma acquire a metastatic phenotype is a key issue. One possible mechanism is that metastasis is driven by microenvironment-induced switching between noninvasive and invasive states. However, whether switching is a reversible or hierarchical process is not known and is difficult to assess by comparison of primary and metastatic tumors. We address this issue in a model of melanoma metast...

The macular region of the primate retina is yellow in color due to the presence of the macular pigment, composed of two dietary xanthophylls, lutein and zeaxanthin, and another xanthophyll, meso-zeaxanthin. The latter is presumably formed from either lutein or zeaxanthin in the retina. By absorbing blue-light, the macular pigment protects the underlying photoreceptor cell layer from light damag...

Microspectrophotometrically derived difference spectra from the barnacles Balanus amphitrite and B. eburneus show that a blue illumination after an orange illumination causes a decrease in absorption in the blue region and an increase in absorption in the green-yellow region, with an isosbestic point around 535 nm. Orange-following-blue illumination causes the reverse changes. The dark time bet...