| 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) |
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| 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) |
| 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) |
| 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-bird | <zoology> A species of tern, especially. The sooty tern (Sterna fuliginosa) of the West Indies. In the Bahama Islands the name is applied to the tropic bird, Phaethon flavirostris. Source: Websters Dictionary (01 Mar 1998) |
| 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) |