| mutacism | A form of stammering in which the letter m is frequently substituted for other consonants. Synonym: mutacism. Origin: G. My, the letter u (05 Mar 2000) |
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| mutagen | <chemistry, oncology> An agent that can cause an increase in the rate of mutation, includes X-rays, ultraviolet irradiation (260 nm) and various chemicals. (18 Nov 1997) |
| mutagenesis | The development of mutations. (09 Oct 1997) |
| mutagenesis, insertional | Mutagenesis where the mutation is caused by the introduction of foreign DNA sequences into a gene. This may occur spontaneously in vivo or be experimentally induced in vivo or in vitro. Proviral DNA can be inserted into or adjacent to a cellular proto-oncogene. Insertion of the provirus can cause mutations by interrupting coding sequences or regulatory elements, or cause unregulated expression of the proto-oncogene resulting in tumour formation. (12 Dec 1998) |
| mutagenesis, site-directed | Mutagenesis where the mutation is caused by in vitro induction directed at a specific site in a DNA molecule. The most common method involves use of a chemically synthesised oligonucleotide mutant which can hybridise with the DNA target molecule. The resulting mismatch-carrying DNA duplex may then be transfected into a bacterial cell line and the mutant strands recovered. (12 Dec 1998) |
| mutagenic | <genetics, molecular biology> Inducing genetic mutation. Origin: Gr. Gennan = to produce (18 Nov 1997) |
| mutagenicity test | <investigation> Range of tests using biological systems to see whether compounds can cause mutations. (14 Nov 1997) |
| mutagenicity tests | Tests of chemical substances and physical agents for mutagenic potential. They include microbial, insect, mammalian cell, and whole animal tests. (12 Dec 1998) |
| mutagens | Chemical agents that increase the rate of genetic mutation by interfering with the function of nucleic acids. A clastogen is a specific mutagen that causes breaks in chromosomes. (12 Dec 1998) |
| mutan synthetase | <enzyme> Streptococcus mutans enzyme synthesises water-insoluble glucan with mainly alpha-1,3 linkages; a virulence factor in dental caries Registry number: EC 2.4.1.- Synonym: mutansynthetase, 1,3-alpha-d-glucan synthase, sucrose-1,3-alpha-glucan 3-alpha-glucosyltransferase, glucosyltransferase b, gtfb protein (26 Jun 1999) |
| mutant | <biology, genetics> Refer to an organism, population, gene, or chromosome, etc. Which differs from the corresponding wild type by one or more mutations. (13 Nov 1997) |
| mutant gene | A gene that has been changed from an ancestral type, not necessarily in the current generation. See: mutant, mutation. (05 Mar 2000) |
| mutarotase | <enzyme> An enzyme catalyzing the reversible interconversion of alpha-and beta-aldoses (e.g., alpha-and beta-d-glucose); also acts on l-arabinose, d-xylose, d-galactose, maltose, and lactose. Synonym: aldose mutarotase, mutarotase. (05 Mar 2000) |
| mutarotation | <chemistry> Name given to the phenomenon that occurs when glucose is dissolved in water. There is an equilibrium that is formed between the open-chain form and the alpha and beta pyranose forms. The beta is the most stable conformation because it puts the -OH in an equatorial position and thus most of the glucose in the aqueous solution is in the beta form. (09 Jan 1998) |
| mutase | <enzyme> An enzyme that catalyses the switching of functional groups on a molecule. (13 Nov 1997) |