Carotenoid composition and conformation in retinal oil droplets of the domestic chicken

PLoS One. 2019 May 31;14(5):e0217418. doi: 10.1371/journal.pone.0217418. eCollection 2019.

Abstract

Carotenoid-containing oil droplets in the avian retina act as cut-off filters to enhance colour discrimination. We report a confocal resonance Raman investigation of the oil droplets of the domestic chicken, Gallus gallus domesticus. We show that all carotenoids present are in a constrained conformation, implying a locus in specific lipid binding sites. In addition, we provide proof of a recent conclusion that all carotenoid-containing droplets contain a mixture of all carotenoids present, rather than only a subset of them-a conclusion that diverges from the previously-held view. Our results have implications for the mechanism(s) giving rise to these carotenoid mixtures in the differently-coloured droplets.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carotenoids / analysis
  • Carotenoids / chemistry*
  • Chickens / physiology*
  • Color Vision / physiology*
  • Lipid Droplets / chemistry*
  • Lipid Droplets / physiology
  • Microscopy, Confocal
  • Molecular Conformation
  • Retina / cytology*
  • Retina / physiology
  • Spectrum Analysis, Raman

Substances

  • Carotenoids

Grants and funding

This work was supported by the European Research Council (http://erc.europa.eu) through the Advanced Grant PHOTPROT (contract No. 267333, to BR); the French Agence Nationale de la Recherche (http://www.agence-nationale-recherche.fr) through contracts BIOPHYSMEMBPROT (contract No. ANR-07-CEX-009-0, to BR) and CYANOPROTECT (Blanc SVSE 8 2011, to BR); the CEA (http://www.cea.fr) interdisciplinary program Technology for Health (MEDIASPEC project, to BR); and The French Infrastructure for Integrated Structural Biology (FRISBI; http://frisbi.eu) ANR-10-INBS-05 (to BR). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.