The structure and polysaccharide cytochemistry of the jelly envelopes of the egg of the frog, Rana pipiens

Abstract

The structure and polysaccharide constitution of the jelly capsuIe of the egg of R a m pipiens is described. Microscopic examination of the jelly capsule revealed the presence of five discrete jelly layers that differed clearly in their response to selected cytochemical tests. These layers were classified as M1-through M5 from the inner to the outermost layer. A sixth layer occasionally could be observed between M3 and M4.All layers contain neutral mucopolysaccharides. In addition layers M1 and M3 contain sulphated mucopolysaccharides, M2 and M4 contain non-sulphated acid mucopolysaccharjdes, and layer M5 contains both sulphated and non-sulphated acid mucopolysaccharides. M2 inay also contain a small quantity of sulphated mucopolysaccharides. The layer that occasionally appears between M3 and M4 is probably an area in which free acidic groups are in higher concentration than i n adjacent areas rather than being a discrete jelly layer. Neither hyaluronic acid nor sialic acid was localized by the methods employed.The possible significance of some of these constituents is discussed.

Structure and Macromolecular Composition of the Egg and Embryo Jelly Coats of the Anuran Lepidobatrachus laevis

“…The number and structural complexity of the jelly coats varies considerably, e.g., among anurans, Rana pipiens eggs have been reported to contain from three to six layers (24,30,32), three or four layers were reported for Xenopus faevis eggs (7, 10, 38), four jelly coats have been described in Bufo arenarum eggs (2) and five layers were reported in Discoglossus pictus eggs (3). Few reports on the jelly of urodele eggs have appeared; however, studies of Notophthalmus viridescens have revealed the presence of five jelly coats (22).…”

Morphological Diversity and Evolution of Egg and Clutch Structure in Amphibians

“…Daniel (1937) and others pointed out that some layers have discernible but less discrete subdivisions. We designate these subdivisions as 'zones' to suggest areas that are less easily visualized than layers (see Steinke and Benson, 1970), but we do not imply that all zones of nonstained eggs are visible.…”

Glycopattern analysis and structure of the egg extra-cellular matrix in the Apennine yellow-bellied toad, <i>Bombina pachypus (Anura: Bombinatoridae)</i>

“…Similar to B. pachypus J 1 , a strongly acidic layer adjacent to the FE is found in a number of species [4,12,[53][54][55] and contains both carboxylated and sulfated glycoconjugates. Carboxylated glycans probably include sialic acid, as suggested by positivity to WGA lectin, which is involved in several functions, such as viscosity of the layer, three-dimensional conformational stability, protection from attack and degradation, hydration, osmotic regulation as well as sperm interaction [56][57][58].…”

“…In most studies, the whole jelly coat is taken for biochemical analysis, without distinguishing between the layers or the sublayers. Histochemical studies have demonstrated that the distribution of neutral and acidic carbohydrates varies among the layers in several species [1,4,12]. Lectin-binding experiments on jelly coat layers have revealed heterogeneity in the distribution of binding sites among 307 307 307 307 307…”