Unique Pigmentation Research Articles

Identification of Brook, Brown, Rainbow, and Cutthroat Trout Larvae

Abstract Cultured metalarvae and mesolarvae of brook trout Salvelinus fontinalis, brown trout Salmo trutta, rainbow trout Salmo gairdneri, and cutthroat trout Salmo clarki were analyzed for distinguishing pigmentation patterns, variation in size and abundance of oil globules in the yolk, and differences in 48 morphometric and meristic characters by comparison of percent standard lengths and multivariate statistical techniques. Rainbow and cutthroat trouts differed from each other only in that the insertion of the dorsal fin and origin of the adipose fin were more posterior in rainbow trout. Brown trout differed from the other species in having longer pectoral fins, an elliptical yolk and unique pigmentation on the lower jaw, caudal fin, and adipose fin. Brook trout differed from the other species by having numerous minute oil globules in the yolk; a distinctively longer adipose fin; prominent pigmentation on the anterior margin of the mandible, caudal fin, and adipose fin; and a greater number of dorsal a...

IDENTIFICATION OF AN R-LOCUS REGION THAT CONTROLS THE TISSUE SPECIFICITY OF ANTHOCYANIN FORMATION IN MAIZE

The R locus in maize controls the tissue specificity of anthocyanin formation. Recombination between two different R-locus alleles with unique pigmentation domains has resulted in the generation of a nonparental allelic type that displays a third kind of tissue specificity. These novel changes in tissue specificity occurred in very low frequency (1 x 10(-5)). In light of this finding and of recent results concerning the regulation by R of the enzyme UDPG: flavonoid 3-0-glucosyltransferase, specified by the B(z) locus, a model dealing with the genetic control of tissue-specific functions in multicellular organisms is proposed.

Colour receptors in the eye of the digger wasp, Sphex cognatus Smith: evaluation by selective adaptation.

Pigment granule migration in pigment cells and retinula cells of the digger wasp Sphex cognatus Smith was analysed morphologically after light adaptation to natural light, dark adaptation and after four selective chromatic adaptations in the range between 358 nm and 580 nm and used as the index of receptor cell sensitivity. The receptor region of each ommatidium consists of nine retinula cells which form a centrally located rhabdom. Two morphologically and physiologically different visual units can be described, defined by the arrangement of the rhabdomeric microvilli, the topographical relationship of the receptor cells with respect to the eye axes and the unique retinula cell screening pigmentation. These two different sets of ommatidia (type A and B) are randomly distributed in a ratio of 1:3 throughout the eye (Ribi, 1978b). Chromatic adaptation experiments with wavelengths of 358nm, 443nm, 523nm and 580nm and subsequent histological examination reveal two UV receptors, two blue receptors and four yellow-green receptors in type A ommatidia and two UV receptors and six green to yellow-green receptors in type B ommatidia. The pigments in cells surrounding each ommatidium (two primary pigment cells, 20 secondary pigment cells and four pigmented cone extensions) were not affected significantly by the adaptation experiments.