Single Carotenoid Research Articles

The Utilization of Carotenoids by the Hen and Chick

Abstract THUDICHUM (1869) observed that the pigment in egg yolk was unsaponifiable and was exclusively soluble in fat solvents and gave it the name lutein. Schunk (1903) isolated the egg yolk pigment and showed by spectroscopic study that it was xanthophyll. Kuhn et al. (1931) reported, in contrast to Schunk (1903), that the pigment of the egg yolk was not a single carotenoid, but that the egg yolk contained zeaxanthin in addition to the lutein. Palmer and Kempster (1919) later demonstrated that the carotenoids which are present in egg yolks depended on the carotenoids fed. Mann (1946), and Brown (1938) have subsequently demonstrated that, in general, hens deposit in the egg yolk at least part of any carotenoids consumed. Most of the early work on avian carotenoid metabolism has been done with “total carotenoids” or “total xanthophylls,” or with crude carotenoid extracts and concentrates. However, some work has been done with…

Carotenoids of the scarlet ibis

1. 1. The orange egg-yolk, red tarsal skin and bright scarlet feathers of an ibis, Guara rubra, captured in Venezuela and received by the San Diego Zoo, yielded a number of carotenoid fractions, the majority of which are new xanthrophylls. 2. 2. Six fractions were recovered from the yolk: one whose acidic derivative was somewhat reminiscent of astacene (absorbing maximally at 466 mμ rather than at 470–472 mμ in petroleum ether), and five neutral components, absorbing maximally at single major peaks in the blue-violet to blue region. 3. 3. From tarsal skin a single carotenoid was recovered, showing a single absorption maximum at 458 mμ, but distinguishable from either echinenone or canthaxanthin. 4. 4. By chromatography and the action of selective solvents, four neutral and two acidogenic xanthophylls were obtained from the feathers. A prominent neutral fraction was canthaxanthin, the 3,3′-diketo-β-carotene, found also in flamingo feathers. The single absorption maxima of the two acidic Guara xanthophyll derivatives (484 and 475 mμ respectively) distinguished them from astacene (490 mμ; all in pyridine) recoverable from many invertebrates, from some fishes, and flamingo feathers.

Sensory Cells and Pigment Distribution in the Tail of the Ammocoete

ABSTRACT The ammocoete of Lampetra planeri (Bloch) contains a single carotenoid, lutein, partly esterified and partly in the free state. The pigment is distributed in lipophores in the sub-dermal tissues, and plays no part in the colour changes of the animal. The epidermis of the tail contains numerous sensory cells of a type previously undescribed, which satisfy the requirements predicted for the photoreceptors responsible for the light reaction of the animal. Evidence is presented that these sensory cells are innervated by branches of the lateral line nerves. Similarities are indicated between the sensory cells of the ammocoete and simple photoreceptor systems of certain invertebrates.