| mating type gene | Genes that, in Saccharomyces cerevisiae specify into which of the two mating types (a and _) a particular cell falls. Only unlike mating type haploids will fuse. The interest derives from the way in which mating type is switched, the existing gene is removed and a new gene, derived from a (silent) master copy elsewhere in the genome is spliced in. Later this gene will in its turn be replaced by a new copy of the old gene, also derived from a silent master. The a and _ genes code for pheromones that affect cells of the opposite mating type. Similar mating type genes are known from other yeasts and the switching mechanism (cassette mechanism) may be used more generally. (18 Nov 1997) |
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| matrass | <chemistry> A round-bottomed glass flask having a long neck; a bolthead. Origin: F. Matras; perh. So called from its long narrow neck; cf. OF. Matras large arrow, L. Materis, mataris, matara, a Celtic javelin, pike; of Celtic origin. Source: Websters Dictionary (01 Mar 1998) |
| matrical | Relating to any matrix. Synonym: matricial. (05 Mar 2000) |
| matricaria | The flowers of Matricaria chamomilla (family Compositae); used internally as a tonic and externally as a counterirritant. See: chamomile. Origin: L. Matrix, womb (05 Mar 2000) |
| matrices | Plural of matrix. Origin: L. (05 Mar 2000) |
| matricial | Relating to any matrix. Synonym: matricial. (05 Mar 2000) |
| matricide | 1. The killing of one's mother. Compare: patricide. 2. One who commits such an act. Origin: L. Mater, mother, + caedo, to kill (05 Mar 2000) |
| matrilineal | Denoting descent through the female line. Origin: L. Mater, mother, + linea, line (05 Mar 2000) |
| matrimony | 1. The union of man and woman as husband and wife; the nuptial state; marriage; wedlock. "If either of you know any impediment, why ye may not be lawfully joined together in matrimony, ye do now confessit." (Book of Com. Prayer (Eng. Ed)) 2. A kind of game at cards played by several persons. <botany> Matrimony vine, a climbing thorny vine (Lycium barbarum) of the Potato family. Synonym: Marriage, wedlock. See Marriage. Origin: OE. Matrimoine, through Old French, fr. L. Matrimonium, fr. Mater mother. See Mother. Source: Websters Dictionary (01 Mar 1998) |
| matrix | Ground substance in which things are embedded or that fills a space (as for example the space within the mitochondrion). most common usage is for a loose meshwork within which cells are embedded (e.g. Extracellular matrix), although it may also be used of filters or absorbent material. (18 Nov 1997) |
| matrix band | A metal or plastic band secured around the crown of a tooth to confine restorative material to be adapted into a prepared cavity. (05 Mar 2000) |
| matrix bands | Devices which provide an artificial temporary wall, or matrix, used in filling a prepared cavity. (12 Dec 1998) |
| matrix calculi | <radiology> Radiolucent, associated with Proteus infection, composition: 2/3 mucoprotein, 1/3 mucopolysaccharide see also: renal calculi (12 Dec 1998) |
| matrix calculus | A yellowish-white to light tan urinary calculus containing calcium salts, with the consistency of putty; composed chiefly of an organic matrix consisting of a mucoprotein and a sulfated mucopolysaccharide, and usually associated with chronic infection. (05 Mar 2000) |
| matrix Gla protein | A calcium binding protein. (05 Mar 2000) |