| egg | A structure which the females of certain animal species lay as a means of reproduction, it contains a fertilized zygote and nutrition in the form of yolk for the developing offspring, sometimes contains other substances (e.g., the white of a hen's egg), sometimes surrounded by a protective outer shell. (09 Oct 1997) |
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| egg albumin | <protein> A major protein constituent of egg white. A phosphoprotein of 386 amino acids (44 kD) with one N linked oligosaccharide chain. Synthesis is stimulated by oestrogen. The gene, of which there is only one in the chicken genome, has eight exons and is of 7.8 kbase, it was one of the first genes to be studied in this sort of detail. (18 Nov 1997) |
| egg cell | The unfertilised ovum. (05 Mar 2000) |
| egg cluster | One of the clumps of cells resulting from the breaking up of the gonadal cords in the ovarian cortex; these clumps later develop into primary ovarian follicles. (05 Mar 2000) |
| egg coat | A layer of glycoproteins and other stuff which surrounds an egg (ovum), just outside of the egg's cell membrane. The coat protects the egg, and for organisms which practice external fertilization (fertilization outside of the parents' bodies) it can help prevent the sperm of other species from entering the egg. For the eggs of mammals, the egg coat is called the zona pellucida and for sea urchins (a popular study organism for developmental biologists) it is called the vitelline layer. (09 Oct 1997) |
| egg donation | Donation of an ovum by one woman to another who attempts to become pregnant by in vitro fertilization. (09 Oct 1997) |
| egg drop syndrome | <syndrome> A disease of chickens caused by an adenovirus and characterised by production of soft-shelled and shell-less eggs in apparently healthy birds. (05 Mar 2000) |
| egg membrane | The investing envelope of the ovum; a primary egg membrane is produced from ovarian cytoplasm (e.g., a vitelline membrane); a secondary egg membrane is the product of the ovarian follicle (e.g., the zona pellucida); a tertiary egg membrane is secreted by the lining of the oviduct (e.g., a shell). (05 Mar 2000) |
| egg polarity gene | A gene whose product distribution in the egg determines the anterior posterior axis of subsequent development. Best characterised in Drosophila: See: bicoid, maternal effect gene. (18 Nov 1997) |
| egg proteins | Proteins which are found in eggs or ova from any species. (12 Dec 1998) |
| egg proteins, dietary | Proteins found in eggs which are consumed as a food. (12 Dec 1998) |
| egg shell nail | Thinning of nails resulting in bending and breaking of the free edge, with longitudinal fissures. Synonym: egg shell nail. Origin: hapalo-+ G. Onyx (onych-), nail (05 Mar 2000) |
| egg squash | A variety of squash with small egg-shaped fruit. Source: Websters Dictionary (01 Mar 1998) |
| egg white | The white of an egg, especially a chicken's egg, used in cooking. It contains albumin. (12 Dec 1998) |
| egg yolk | The stored nutrient of the egg and the yellow portion of the egg of a bird. (12 Dec 1998) |
| vitelline layer of egg | <zoology> The membrane, usually of protein fibres, immediately outside the plasmalemma of the ovum and the earlier stages of the developing embryo. Its structure and composition vary in differing animal groups. (18 Nov 1997) |
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| centrolecithal egg | An egg in which the yolk is concentrated near the centre of the egg cell, as is the case in many of the insects. (05 Mar 2000) |
| microlecithal egg | An egg containing a small amount of deutoplasm. (05 Mar 2000) |
| mosaic egg | <biology> At one time a distinction was drawn between those organisms in which the egg seemed to have a firmly committed fate map built in and regulating embryos. In the former, after the first cleavage one blastomere was committed to produce one set of tissues, the other blastomere a different set and removal of one blastomere led to the production of an incomplete embryo. This was particularly obvious in mollusc development where one blastomere had the polar lobe material. This early differentiation (or determination) of blastomeres for particular fates was in distinction to regulating embryos in which the removal of one blastomere did not matter, the other blastomere compensating and producing a full set of tissues. The distinction is, however, only based upon the timing of differentiative events and within a few divisions the regulating embryo also becomes a mosaic of determined cells. (18 Nov 1997) |
| primary egg membrane | See: egg membrane. (05 Mar 2000) |
| high-egg-passage vaccine | Living Flury strain rabies virus at the 180th to 190th level egg passage (embryonate eggs), used for vaccination of cattle and cats, low-egg-passage (LEP) vaccine: at the 40th to 50th passage level, containing 103 to 104 mouse LD50; nonpathogenic in dogs but retains some pathogenicity for cattle and cats. (05 Mar 2000) |
| sea egg | <zoology> A sea urchin. Source: Websters Dictionary (01 Mar 1998) |
| secondary egg membrane | See: egg membrane. (05 Mar 2000) |
| homolecithal egg | An egg in which the total amount of yolk is small and fairly uniformly distributed throughout the cytoplasm. Synonym: isolecithal egg. (05 Mar 2000) |
| Dorset's culture egg medium | A medium for cultivating Mycobacterium tuberculosis; it consists of the whites and yolks of four fresh eggs and a solution of sodium chloride. (05 Mar 2000) |
| isolecithal egg | An egg in which the total amount of yolk is small and fairly uniformly distributed throughout the cytoplasm. Synonym: isolecithal egg. (05 Mar 2000) |
| telolecithal egg | An egg containing a relatively large quantity of deutoplasm concentrated at the abapical pole; e.g., egg's of reptiles and birds. (05 Mar 2000) |
| tertiary egg membrane | See: egg membrane. (05 Mar 2000) |
| ultrasonic egg recovery | Obtaining an egg for in vitro fertilization by means of an ultrasonically guided needle aspiration of ovarian follicles; may be performed transvesically or via the cul-de-sac. (05 Mar 2000) |
| low-egg-passage vaccine | See: rabies vaccine, Flury strain egg-passage. (05 Mar 2000) |