title: Production of [14C]-labeled 3-hydroxy-L-kynurenine in a butterfly, Heliconius charitonia L. (Heliconidae), and precursor studies in butterfly wing ommatins.
abstract: A method was developed to produce radiolabeled 3-hydroxy-L-kynurenine by injection of [14C]-L-tryptophan into pupae of the heliconid butterfly, Heliconius charitonia, which was converted into [14C]-3-hydroxy-L-kynurenine and deposited as a wing pigment. Extractions of 3-hydroxykynurenine (3-OHK) with 60% methanol from wings yielded in 14.4 micrograms per mg dry weight. In extracts from yellow wing areas, 3-OHK represented 100% of detectable amino acids. Resulting specific radioactivity of [14C]-3-OHK was between 0.05 and 0.07 mCi/mmol when 0.5 microCi [14C]-tryptophan was injected into pupae 1 or 2 days before emergence of the butterfly. Incorporation of [14C]-3-OHK into wing ommochromes was studied in nymphalid butterflies, Araschnia levana and Precis coenia. After injection into pupae [14C]-3-OHK as well as [14C]-tryptophan were specifically incorporated into red and red-brown wing scales as shown by autoradiography. The same incorporation occurred in isolated wings after incubation in Grace's medium containing [14C]-3-OHK. In Araschnia levana, [14C]-3-OHK offered to left wing pairs was incorporated into dihydroxanthommatin six times more effectively than [14C]-tryptophan offered to right wing pairs from the same specimen. Therefore, 3-OHK seems to be the ultimate precursor of wing ommatins.
authors.affiliation: Abteilung Allgemeine Zoologie, Universität Ulm, Germany.
authors.forename: P B
authors.initials: PB
authors.lastname: Koch
mesh_terms: D000596:Amino Acids / Q000302:isolation & purification / Q000378:metabolism; D000818:Animals; D002080:Butterflies / Q000254:growth & development / Q000378:metabolism*; D002855:Chromatography, Thin Layer; D007737:Kynurenine / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000302:isolation & purification; D010078:Oxazines / Q000302:isolation & purification / Q000378:metabolism*; D010860:Pigments, Biological / Q000096:biosynthesis* / Q000302:isolation & purification; D011679:Pupa; D014364:Tryptophan / Q000378:metabolism; D014921:Wings, Animal / Q000254:growth & development / Q000378:metabolism*; D014966:Xanthenes
chemical_list: D000596:Amino Acids; D010078:Oxazines; D010860:Pigments, Biological; D014966:Xanthenes; C005045:3-hydroxykynurenine; D007737:Kynurenine; C002866:xanthommatin; D014364:Tryptophan