Vol 49, No 2 (2011)
Original paper
Published online: 2011-07-11
Glycopattern analysis and structure of the egg extra-cellular matrix in the Apennine yellow-bellied toad, Bombina pachypus (Anura: Bombinatoridae)
DOI: 10.5603/FHC.2011.0043
Folia Histochem Cytobiol 2011;49(2):306-316.
Abstract
We studied the glycopatterns and ultrastructure of the extra-cellular matrix (ECM) of the egg of the
Apennine yellow-bellied toad Bombina pachypus, by light and electron microscopy in order to determine structure,
chemical composition and function. Histochemical techniques in light microscopy included PAS and Alcian
Blue pH 2.5 and 1.0, performed also after b-elimination. Lectin-binding was tested with nine lectins (AAA,
ConA, DBA, HPA, LTA, PNA, SBA, UEA-I, WGA). An inner fertilization envelope (FE) and five jelly layers
(J1–J5) were observed, differing in histochemical staining, lectin binding and ultrastructure. Most glycans were
O-linked, with many glucosamylated and fucosylated residues. The fertilization envelope presented a perivitelline
space and a fertilization layer, with mostly neutral glycans. The jelly layers consisted of fibers and granules,
whose number and orientation differed between layers. Fibers were densely packed in J1 and J4 layers,
whereas a looser arrangement was observed in the other layers. Jelly-layer glycans were mostly acidic and particularly
abundant in the J1 and J4 layers. In the J1, J2 and J5 layers, neutral, N-linked glycans were also observed.
Mannosylated and/or glucosylated as well as galactosyl/galactosaminylated residues were more abundant in the
outer layers. Many microorganisms were observed in the J5 layer. We believe that, apart from their functions in
the fertilization process, acidic and fucosylated glycans could act as a barrier against pathogen penetration.
(Folia Histochemica et Cytobiologica 2011; Vol. 49, No. 2, pp. 306–316)
Keywords: amphibiaBombina pachypusegg jellylectinelectron microscopy
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