Calcium, magnesium, copper, iron and zinc are stored in hens’ egg yolk and, except for copper, the majority of these minerals are located in egg yolk granules (Table 1). Presumably, up to 90% calcium, magnesium, iron and zinc are firmly bound in the phosvitin-lipovitellin complex of granules (GREENGARD et al., 1964; TABORSKY, 1980; TUPPER et al., 1954). As was discussed by Richards, copper ions...

toxic effects of malathion and endosulfan to fertile chicken eggs were determined. in-jection of 1.25, 2.5, 5.0 and 10.0 mg/egg of malathion into yolk sac of fertile eggs prior to incubation caused mortality of 10.0, 30.0, 83.33 and 93.33% respectively. similar trend was observed with injection of endosulfan doses. malathion and endosulfan at 1.25 mg/egg caused no pronounced ld50 increase in mo...

Hematopoiesis is the developmentally regulated and tissue-specific process of blood cell production. The predominant anatomic site of hematopoiesis changes several times during murine and human ontogeny. Blood and endothelial cells become morphologically identifiable on embryonic day 7.5 (E7.5) in the developing murine yolk sac blood islands.1 Upon initiation of blood flow through the systemic ...

To reveal differentiation potency of yolk-sac endoderm, this tissue from quail embryos was cultured alone or in association with digestive-tract mesenchymes of chick embryos. When yolk-sac endoderm was cultured alone in vitro, the endoderm of the area vitellina differentiated into the yolk-sac parenchyma, but the endoderm of the extraembryonic area pellucida (EEAP) failed to differentiate into ...

Our goals were to determine the prognostic value of a yolk sac or fetal heart motion seen during an early accurately dated transvaginal ultrasound (TVU). We reviewed 225 consecutive pregnancies for fetal heart motion data. Furthermore, 63 pregnancies following in-vitro fertilization were reviewed for yolk sac information. The TVU was performed between 5 and 6 weeks following presumed conception...

Transforming growth factor β1 (TGFβ1) is shown here to be required for yolk sac haematopoiesis and endothelial differentiation. Mice with a targeted mutation in the TGFβ1 gene were examined to determine the cause of prenatal lethality, which occurs in 50% of homozygous TGFβ1 null (TGFβ1−/−) conceptions. 50% of TGFβ1−/− and 25% of TGFβ1+/− conceptuses were found to die at around 10.5 dpc. The pr...

In the adult, platelets are derived from unipotential megakaryocyte colony-forming cells (Meg-CFCs) that arise from bipotential megakaryocyte/erythroid progenitors (MEPs). To better define the developmental origin of the megakaryocyte lineage, several aspects of megakaryopoiesis, including progenitors, maturing megakaryocytes, and circulating platelets, were examined in the murine embryo. We fo...

The present study aims at investigating muscle development and stress response in early stages of Siberian sturgeon when subjected to different rearing temperatures, by analysing growth and development of the muscle and by assessing the stress response of yolk-sac larvae. Siberian sturgeon larvae were reared at 16°C, 19°C and 22°C until the yolk-sac was completely absorbed. Sampling timepoints ...