title: Mechanism of carotenoid coloration in the brightly colored plumages of broadbills (Eurylaimidae).
abstract: The plumage carotenoids of six species from five genera of broadbills (Eurylaimidae) have been examined. These plumages are crimson, violet, purple-maroon, or yellow. Two genera also have brilliant green plumages that are produced by a combination of structural coloration and unknown carotenoids. Six different carotenoids from nine different plumage patches were identified, including two previously unknown molecules, using high-performance liquid chromatography, mass spectrometry, and MS/MS fragment analysis. The yellow pigment in Eurylaimus javanicus and Eurylaimus ochromalus is identified as the novel carotenoid, 7,8-dihydro-3'-dehydro-lutein. The yellow and green plumages of Psarisomus dalhousiae contain the unmodified dietary carotenoids lutein and zeaxanthin. The brilliant green feathers of Calyptomena viridis contain a mixture of lutein and two other xanthophylls that have previously been found only in woodpeckers (Picinae). The crimson and violet colors of Cymbirhynchus, Sarcophanops, and Eurylaimus are produced by a novel pigment, which is identified as 2,3-didehydro-papilioerythrinone. The molecular structure of this carotenoid was confirmed using (1)H nuclear magnetic resonance, correlated two-dimensional spectroscopy, and two-dimensional nuclear Overhauser effect spectroscopy. Resonance Raman (rR) spectroscopy carried out at room and low temperatures was used to probe the configuration and conformation of 2,3-didehydro-papilioerythrinone in situ within crimson C. macrorhynchos and purple-red E. javanicus feathers. The rR spectra reveal that the pigment is in an all-trans configuration and appears to be relatively planar in the feathers. The likely metabolic pathways for the production of broadbill carotenoids from dietary precursors are discussed.
authors.affiliation: Department of Ecology and Evolutionary Biology and Peabody Museum of Natural History, Yale University, 21 Sachem Street, New Haven, CT, 06511, USA, richard.prum@yale.edu.
authors.forename: Richard O
authors.initials: RO
authors.lastname: Prum
authors.forename: Amy M
authors.initials: AM
authors.lastname: LaFountain
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Berg
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Tauber
authors.forename: Harry A
authors.initials: HA
authors.lastname: Frank
mesh_terms: D000818:Animals; D002338:Carotenoids / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003116:Color; D005241:Feathers / Q000378:metabolism*; D005260:Female; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D046109:Passeriformes; D013059:Spectrum Analysis, Raman; D053719:Tandem Mass Spectrometry
chemical_list: D002338:Carotenoids