Ultrastructural investigation of autophagocytosis of melanosomes and programmed death of melanocytes in White Leghorn feathers: a study of morphogenetic events leading to hypomelanosis☆

[摘要] WhiteLeghornchickenshavedecreasedfeathermelanin,notbecausepigmentcellsareabsent,butbecauseofageneticallydeterminedprogrammedcelldeaththatcausespigmentcellstodegenerateprematurelybeforethemelanincanbedepositedinthefeathers.Inthispaper,westudiedthefeathergermsofthisbreedandofcontrolBlackMinorcachickensbylightandelectronmicroscopytoelucidatefurtherthemechanismofcelldeath.WhiteLeghornfeature-germmelanocytesproducedalargenumberofunmelanizedmelanosomeswhich,however,didnotbecomemelanized,norweretheytransferredintothekeratinocytesofthefollicles.Fromday10ofincubationonward,largeautophagosomesappearedinthemelanocytesofWhiteLeghornfeatherfollicles.Theseautophagosomeswereacidphosphatasepositiveandengulfedincompletelymelanizedmelanosomes.Theyalsocontainedmelanosomedegradationproducts.Finally,degenerationofthewholemelanocytefollowed.Thesenecroticmelanocyteswereengulfedbynormal-lookingkeratinocytesofthesamefollicle.InBlackMinorcas,ontheotherhand,therewasanormalsequenceofsynthesis,melanization,andtransferofmelanosomes.Themelanocytesdegeneratedonlyatthetimeofhatching,withouttheformationoflargeautophagosomes.

[学科分类] 生物科学（综合）