Structure and Macromolecular Composition of the Jelly Coats of the Urodele Ambystoma mexicanum: (egg envelopes).

Cleavage-stage embryos of the neotenic urodele Ambystoma mexicanum are surrounded by a fertilization envelope and four macroscopic jelly coats termed J (innermost) through J (outermost). In sections prepared for light microscopy, each of the jelly layers stained with protein stains and the periodic acid-Schiff's reagent, but only J stained with alcian blue at pH 2.5.

Gastric Pepsin in an Anuran Larva: (Lepidobatrachus laevis/pepsinogen).

Larval stomach development was studied in the obligate carnivorous larva of the frog Lepidobatrachus laevis. Pepsin producing cells of the larval stomach were identified using rabbit anti-porcine pepsin and immunohistochemical techniques. Pepsin production was detected at a very early stage of development (stage 24: during opercular development) when the larvae were first competent for feeding.

Structure and Macromolecular Composition of the Egg and Embryo Jelly Coats of the Anuran Lepidobatrachus laevis: (frog jelly coat/fertilization/glycoprotein).

Eggs and cleavage-stage embryos of the frog Lepidobatrachus laevis are encased by 3 μm thick vitelline/fertilization envelope and two jelly layers, termed J (innermost) and J (outermost). Based on light and transmission electron microscopy, J had a dense reticular appearance whereas J had a laminar structure. Direct dissolution of the jelly coats was accomplished by reduction of disulfide bonds with 0.