Interactions between gametes and environment in the toad Xenopus laevis (Daudin) and their relationship to fertilization

Abstract:

The Xenopus laevis egg jelly becomes swollen in different solutions: however; the degree of swelling of each of the three jelly layers and appearance vary depending on the medium. On eggs kept in a medium of low salt concentration, three sublayers of layer J‐3, the “J‐3 complex,” are visible. However, these sublayers cannot be distinguished in eggs hydrated in DeBoer's. Presence of the J‐3 complex is correlated with loss of egg fertilizability. Changes in the swelling of the jelly, disappearance of the J‐3 complex and regaining of egg fertilizability are brought about by brief exposures of the hydrated eggs to DeBoer's. The process that elicits these changes in the jelly was named “jelly reversal.” Jelly reversal is dependent on the solute concentration of the medium, is independent of pH and can be elicited by qualitatively different solutions. Non‐polar solutions act more slowly than those of polar solutes. Regaining of egg fertilizability is dependent on jelly reversal, nature of solute, solute concentration and pH. The phenomena of jelly reversal and regaining of egg fertilizability imply that specific ions of the jelly are needed for fertilization. Hydration of the jelly can form blocks to sperm entry, therefore, the block to polyspermy in Xenopus is not a single event. Layer J‐1 stains metachromatically with toluidine blue and incorporates 35S‐sulfate during its formation. Failure of eggs to regain fertilizability after reversal at low pH is correlated with diminished toluidine blue metachromasia of J‐1. Retention of staining was dependent upon the salt concentration of the medium. Copyright © 1973 Wiley‐Liss, Inc., A Wiley Company

Año de publicación:

1973

Keywords:

Fuente:

scopus

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