| 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) |
|---|---|
| mosaic fundus | A normal fundus to which a deeply pigmented choroid gives the appearance of dark polygonal areas between the choroidal vessels, especially in the periphery. Synonym: fundus tigre, leopard fundus, leopard retina, mosaic fundus, tigroid fundus, tigroid retina. (05 Mar 2000) |
| mosaic inheritance | Inheritance in which the paternal influence is dominant in one group of cells and the maternal in another. Compare: lyonization. (05 Mar 2000) |
| mosaic pattern | On high-resolution CT scans of the lungs, a pattern of brighter and darker regions corresponding to differences in perfusion or aeration; found in some cases of chronic thromboembolism or of bronchiolitis obliterans. Compare: oligaemia. (05 Mar 2000) |
| mosaic viruses | Viruses which produce a mottled appearance of the leaves of plants. (12 Dec 1998) |
| fluid mosaic model | A model used to conceptualise cell membranes, in it, the membranesare described as a structually and functionally asymmetric lipidbilayer studded with embedded proteins that aid in cross-membrane transport. (09 Oct 1997) |
| bovine virus diarrhoea virus | A virus of the genus Pestivirus, in the family Togaviridae, causing bovine virus diarrhoea; New York, Oregon, and Indiana strains of the virus are recognised. Synonym: mucosal disease virus. (05 Mar 2000) |
| abelson leukaemia virus | A defective murine leukaemia virus capable of transforming lymphoid cells and producing a rapidly progressing lymphoid leukaemia after superinfection with friend, moloney, or rauscher virus. (12 Dec 1998) |
| Abelson murine leukaemia virus | A retrovirus belonging to the Type C retrovirus group subfamily (family Oncovirinae) which is associated with leukaemia and produces in vitro transformation of mouse cells. (05 Mar 2000) |
| adeno-associated virus | <virology> A genus of viruses in the family Parvoviridae which are all defective viruses (unable to replicate by themselves) and depend on the co-infection of their host cell by other, nondefective viruses to help them replicate. (09 Oct 1997) |
| adenoidal-pharyngeal-conjunctival virus | <virology> An icosahedral (20-sided) virus that contains DNA, there are over 40 different adenovirus varieties, some of which cause the common cold. (10 May 1997) |
| adenosatellite virus | <virology> A genus of viruses in the family Parvoviridae which are all defective viruses (unable to replicate by themselves) and depend on the co-infection of their host cell by other, nondefective viruses to help them replicate. (09 Oct 1997) |
| african horse sickness virus | A species of orbivirus that causes disease in horses, mules, and donkeys. (12 Dec 1998) |
| african swine fever virus | The lone species of the genus african swine fever-like viruses. The virus causes a fatal disease among domestic pigs in africa and a less virulent infection in europe. The virus is present in soft ticks (ornithodoros moubata), warthogs, or domestic pigs. Originally listed as a species of iridoviridae, the virus exhibits some similarities to poxviridae but its differences warranted placement in a separate genus of an, as yet unknown, family. (12 Dec 1998) |
| AIDS-related virus | An obsolete term for human immunodeficiency virus. (05 Mar 2000) |