Relationships between egg size, chick size at hatching, and chick survival in the Whimbrel Numenius phaeopus

The relationships between egg size, chick size at hatching and chick survival in Whimbrels Numenius phaeopus were studied over a three-year period in the Shetland Isles. Three measurements of chick size at hatching were all positively correlated with egg volume, though the relationship was strongest with hatchling body-weight. In two of the three years the proportion of chicks from a brood which survived to fledging increased significantly with the mean hatching weight of chicks in the brood. Within broods, a significant effect of hatching weight on survival was detectable only up to 7 days after hatching. Between years the egg volumes and hatchling weights of individual female Whimbrels showed relatively little variability, indicating that these attributes could be controlled to a large extent by inheritance.     

Magnal steroid hormone receptors during egg formation in the domestic hen

Levels of magnal estrogen and progesterone receptors during egg formation in the hen were determined. Hens were sacrificed at various times after ovulation and magnal receptor levels were determined by tritiated hormone binding assays. A coincident increase in nuclear estrogen receptor and decrease in cytosol estrogen receptor 2 to 4 h postoviposition was suggestive of in vivo receptor translocation. At 12 to 16 h postoviposition cytosol progesterone receptor increased 2-fold and subsequently declined during the time of preovulatory progesterone surge (8 h to 6 h prior to expected ovulation). These data suggest that changes in circulating levels of estrogen and progesterone, associated with ovulation, are coordinated with oviductal function. This is reflected by fluxes of their respective oviductal receptors.     

Microapplicator and micropipette for inoculation of the embryonated chicken egg.

Aflatoxin G2 was used to test the speed and accuracy of the microapplicator and the micropipette. The 50% lethal dose of both assay systems was approximately the same, and 4.0 mug of G2 had an 85% lethal effect in both systems. The 50% lethal dose of the microapplicator and the micropipette was lower than that of the syringe but, of these, only the micropipette can combine the accuracy of the microapplicator and the speed of the syringe.     

Microapplicator and micropipette for inoculation of the embryonated chicken egg.

Aflatoxin G2 was used to test the speed and accuracy of the microapplicator and the micropipette. The 50% lethal dose of both assay systems was approximately the same, and 4.0 mug of G2 had an 85% lethal effect in both systems. The 50% lethal dose of the microapplicator and the micropipette was lower than that of the syringe but, of these, only the micropipette can combine the accuracy of the microapplicator and the speed of the syringe.     

Changes in glycogen metabolism in chick embryo liver in relation to the formation of glycosomes]

In the chick embryo liver the portion of granular glycogen increases from 15 to 90% of the total content during the period from the 8th till the 14th days of developments. The activity of glycogen synthetase (KF 2.4.1.11) localized in the fraction of granular glycogen increases from 40 to 90% of the total activity in the 18 days old embryo. The activity of phosphorylase (KF 2.4.1.1) is detected in the granular glycogen of the liver only on the 12th day of development (10% of the total activity) and increase up to 80% on the 19th day of development. The maximal activation of glycogen synthetase and phosphorylase is noted after the glycosomes of formation in the developing embryoliver. A suggestion is put forward to the effect that the process of glycosome formation is a factor of the control of glycogen synthetase and phosphorylase activity.     

Amyloid protofilament formation of hen egg lysozyme in highly concentrated ethanol solution

Mutant human lysozymes (Ile56Thr & Asp67His) have been reported to form amyloid deposits in the viscera. From the standpoint of understanding the mechanism of amyloid formation, we searched for conditions of amyloid formation in vitro using hen egg lysozyme, which has been extensively studied from a physicochemical standpoint. It was found that the circular dichroism spectra in the far-ultraviolet region of the hen egg lysozyme changed to those characteristic of a beta-structure from the native alpha-helix rich spectrum in 90% ethanol solution. When the concentration of protein was increased to 10 mg/mL, the protein solution formed a gel in the presence of 90% ethanol, and precipitated on further addition of 10 mM NaCl. The precipitates were examined by electron microscopy, their ability to bind Congo red, and X-ray diffraction to determine whether amyloid fibrils were formed in the precipitates. Electron micrographs displayed unbranched protofilament with a diameter of approximately 70 A. The peak point of the difference spectrum for the Congo red binding assay was 541 nm, which is characteristic of amyloid fibrils. The X-ray diffraction pattern showed a sharp and intense diffraction ring at 4.7 A, a reflection that arises from the interstrand spacing in beta-sheets. These results indicate that the precipitates of hen egg lysozyme are amyloid protofilament, and that the amyloid protofilament formation of hen egg lysozyme closely follows upon the destruction of the helical and tertiary structures.     

Comparative studies on antibody formation against hen egg white lysozyme and its split fragment.

A peptide fragment Fr. 17 (Lys1-Cys-Asn27 Leu129-Cys-Ala122) of hen egg white lysozyme (HL) was previously found to retain at least one antigenic determinant region of the native protein. In this work a highly purified preparation of Fr. 17, contaminated with less than 0.01% HL and less than 1% of other fragments was found to be strongly immunogenic to rabbits. The kinetic patterns of antibody formation against Fr.17, assayed by passive hemagglutination (PHA), were quite different from those of antibody formation against HL. The specificity of the antibody elicited to Fr. 17 was mainly directed to the Fr. 9-10-a region (Ala11-Asn27) while that of the antibody elicited to the Fr. 17 region in native HL was directed to the Fr. 15-b region (Lys1-Cys-Ala10 Leu129-Cys-Trp123). It is concluded that in the process of antibody formation, the recognition of the Fr. 17 region in native HL is different from that of fragment Fr. 17.