Passage of Ovoglobulins Through the Shell Membrane

Abstract

It has been shown by Pearl and Curtis 1 that during the sojourn of the egg in the uterus the weight and nitrogen content of the albumen increases by the addition of a nitrogenous solution after the shell membrane has been formed. Data were collected to observe what kind of nitrogenous materials were added after the shell membrane was formed.

Mature eggs to be used as controls were obtained in the morning from hens just beginning to lay a clutch of eggs, so that it was likely that they would lay the next day. Four to 6 hours after the egg was laid the hens were sacrificed and the immature eggs removed from the uterus. At this time the eggs were found with the shell membrane formed. The mature egg of the morning and the later immature egg from the same hens were analyzed as pairs.

The eggs so obtained were separated into yolk, thick albumen and thin albumen. A screen, similar to that described by Holtz 2 and Almquist was used for the separation of the thick from the thin albumen. Thirteen pairs of eggs were separated in this manner. The results of the separation of the albumen and the yolk were found to confirm Pearl and Curtis in that only 60% of the albumen by weight, and 90% of the nitrogen in the albumen were present after the shell membrane was formed, and it was for the most part thick albumen.

The albumens were diluted, the ovomucins were removed with the centrifuge, and the supernatant fluid was made up to volume with a small amount of sodium chloride or sodium sulfate present to prevent precipitation of the ovoglobulins. The ovoglobulins and the ovalbumins were separated by precipitation of the ovoglobulins with 1.5 M sodium sulfate by a technique similar to that of Howe 3 for blood serum proteins. Non-protein nitrogen was determined by using Alman's tannic acid reagent or 2.12 sodium sulfate for protein precipitation. The ovomucoid content was determined by heat coagulation of the other proteins in the presence of acetate buffer approximately pH 4.7 and 0.2 M sodium sulfate. No attempt was made to separate the ovoglobulins or ovalbumins. Nitrogen was determined by macro-Kjeldahl.