XB-IMG-83214
Xenbase Image ID: 83214
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Fig. 4. Secretion of allurin in the frog oviduct and its application to the egg. (A) The X.
laevis oviduct consists of tubular jelly secreting glands capped by arches of epithelial cells
that face the oviduct lumen. Below the arches, cells that synthesize and secrete jelly
glycoconjugates are filled with large, strongly basophilic granules. The cells of each tubular
gland fan out from a central duct that empties into the lumen at the crevices between the
epithelial arches. Bar, 25 μm. (B) Each arch contains at its center a capillary loop filled with
blood cells. Covering the capillary is a single layer of ciliated epithelial cells and interspersed
among these cells are occasional secretory cells that have clusters of lightly stained granules
(asterisks). These are thought to be the allurin producing cells. Bar, 10 μm. From Chandler
and Roberson, 2008 with copyright permission from Jones and Bartlett Publishers (C)
Electron micrograph of cilia emerging at the apical plasma membrane of arch epithelial cells.
Bar, 1 μm. (D) Immunocytochemical localization of allurin at the ultrastructural level. Arrows
point to colloidal gold beads marking the presence of allurin on the extracellular surface of
the cilia. Bar, 0.4 μm. (E) Immunocytochemical localization of allurin as it is applied to an egg
passing down the oviduct. The secondary antibody signal (red) is superimposed on a
transmitted light image of the egg and oviductal epithelium. Heavy deposits of allurin on the
ciliary border are mixed with jelly and �brushed� onto the egg. Bar, 10 μm. (F) In the freshly
spawned egg, allurin has become concentrated in the outmost (J3) jelly layer poised to be
released into the medium. Bar, 100 μm. From Xiang et al., Dev. Biol. 275:343-355 (2004) with
copyright permission from Elsevier Science. Image published in: Burnett LA et al. (2008) Copyright © 2008. Reproduced with permission of the Publisher, University of the Basque Country Press.
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