The so-called yolk-nucleus of the young oocytes of birds is situated close to the nucleus. It is a homogeneous, spherical mass with radiating projections. Histochemical tests show it to be rich in RNA. Lipid bodies of diverse nature and mitochondria are aggregated in its vicinity. The yolk-nucleus disintegrates as the yolk-bodies are formed, and meanwhile the cytoplasmic inclusions that had agg...

Address for Correspondence: Dr. Geetanjali Srivastava, Junior resident IIIrd year,Department of Anatomy, Era’s Lucknow medical college, Lucknow-226003, Uttar Pradesh, India. 9792171135, E-Mail: [email protected] Introduction: The yolk sac is the first extra embryonic structure that becomes sonographically visible within the gestational sac and acts as the primary route of excha...

Riboflavin-binding protein (RBP) and phosvitin are phosphoglycoproteins transferred from the plasma of laying hens into the yolk of developing oocytes. We have examined the effect of phosphate removal on this yolk deposition process. Unmodified yolk RBP and phosvitin contain, respectively, 8.3 and 109 residues of phosphate/molecule. Complete dephosphorylation of yolk RBP caused a 20-min decreas...

Rat embryos, explanted with their embryonic membranes during the early stages of organogenesis (H-l (H days gestation), were grown in culture in roller tubes. Yolk-sac antibody (sheep anti rat yolk-sac gamma globulin), known to be teratogenic when injected into pregnant rats, was added to the culture medium. At concentrations of 01 mg/ml or more the antibody caused gross retardation of growth a...

To examine the nature of cytoplasm determinants for dorsal specification in zebrafish, we have developed a method in which we remove the vegetal yolk hemisphere of early fertilized eggs (vegetal removed embryos). When the vegetal yolk mass was removed at the 1-cell stage, the embryos frequently exhibited typical ventralized phenotypes: no axial structures developed. The frequency of dorsal defe...

When one heats the yolk, changes occur in the fragile elements that serve to support the vital life force within the egg. The egg yolk, in many ways, is not very different from your own cells. Once your temperature goes above 105 degrees you will start to suffer serious health problems. Similarly, heating the yolk above 105 degrees will also start to cause structural changes in many of the high...

The precise function of the yolk platelets of sea urchin embryos during early development is unknown. We have shown previously that the chemical composition of the yolk platelets remains unchanged in terms of phospholipid, triglyceride, hexose, sialic acid, RNA, and total protein content after fertilization and early development. However, the platelet is not entirely static because the major 16...

Vitellogenesis or maternal yolk formation is considered critical to the reproduction of egg-laying animals. In invertebrates, however, most of its regulatory genes are still unknown. Via a combined mapping and whole-genome sequencing strategy, we performed a forward genetic screen to isolate novel regulators of yolk production in the nematode model system Caenorhabditis elegans. In addition to ...

A partial cDNA clone for the 48,000 dalton yolk polypeptide gene from Anastrepha suspensa was isolated from a cDNA expression library using a yolk polypeptide antibody probe and hybridization to the Drosophila melanogaster yolk protein 1 gene. The sequenced DNA has greatest homology to the yolk protein genes from Ceratitis capitata, D. melanogaster, and Calliphora erythrocephala and, similar to...

The heat resistance and growth possibilities of various members of the Micrococcaceae in egg yolk and egg yolk with added salt were determined. Egg yolk alone protected members of the Micrococcaceae considerably against heat. Whereas in water Staphylococcus aureus S6 had a decimal reduction time (D) value of 66 s at 55 degrees C, its D value in egg yolk at the same temperature was 246 s. In sal...