The peri-albumen layer: a novel structure in the envelopes of an avian egg.
The present paper describes a novel structure, termed the peri-albumen layer, in the egg-envelopes of the quail Coturnix japonica. It reacts with Alcian blue and exists between the egg white and the shell membrane. Ultrastructurally, it is of fine granular structure and forms a fenestrate sheet, the width of which is 190 nm or less. Isolated materials of the peri-albumen layer include an Alcian-blue-positive polysaccharide of 260 kDa, and three glycoproteins of 160, 108 and 52 kDa. The layer is supplied to an egg when it passes through the magnum-isthmus junction, the normalized length of which is 0.62-0.63 of the oviduct. The mucosa of the junction consists exclusively of a luminal epithelium. It is apparently distinct from the mucosa of the magnum and the isthmus, which consist of a luminal epithelium and tubular glands. The luminal epithelium of the magnum-isthmus junction stains prominently with Alcian blue and consists of alternately distributed ciliated cells and granular cells. Immunohistochemistry with an antiserum raised against the materials of the peri-albumen layer revealed the staining of the peri-albumen layer of the egg, and secretory cells of the luminal epithelium at the magnum-isthmus junction. It was concluded that the materials of the peri-albumen layer are produced by secretory cells at the magnum-isthmus junction of the oviduct.
Sultana
F
F
Department of Animal Resource Production, The United Graduate School of Agricultural Science, Gifu University, Gifu 501-1193, Japan.
Yokoe
A
A
Ito
Y
Y
Mao
K M
KM
Yoshizaki
N
N
D000818:Animals; D003370:Coturnix / Q000196:embryology*; D005260:Female; D007150:Immunohistochemistry / Q000379:methods; D008854:Microscopy, Electron; D010057:Oviducts / Q000378:metabolism / Q000648:ultrastructure; D010063:Ovum / Q000737:chemistry / Q000648:ultrastructure*