| cis-prenyl transferase | <enzyme> Involved in dolichol biosynthesis Registry number: EC 2.5.1.- Synonym: cis-prenyltransferase (26 Jun 1999) |
|---|---|
| cis-toluene dihydrodiol dehydrogenase | <enzyme> Nad specific dehydrogenase; reduces ring structure Chemical name: 1,2-dihydroxy-3-methylcyclohexa-3,5-diene dehydrogenase Registry number: EC 1.3.- Synonym: ctd dehydrogenase (26 Jun 1999) |
| cis-trans-isomerases | <enzyme> Enzymes that catalyze the rearrangement of geometry about double bonds. Registry number: EC 5.2 (12 Dec 1998) |
| cis trans test | <molecular biology> The complementation test with two or more interacting genes placed in cis and in trans relationships to each other. A double mutant genome is used in the cis test made from the two single mutant genomes used in the trans test by recombination. If the wild type phenotype is restored by both cis and trans arrangements it is concluded that the two mutations are in different genes and hence that the phenotype is determined by more than one gene. If the trans test is negative and the cis positive this means that the two mutations are in the same gene. If both tests are negative then at least one of the mutations must be dominant. Thus the double test provides a means of fine mapping of genes. A lab test which is used to determine whether two mutations of different genes which affect the same phenotype are on the same functional unit (indicating a cis configuration of the mutated genes) or on different functional units (indicating a trans configuration of the mutated genes). (A functional unit can be a chromosome.) The test is done by mating an individual that has one of the mutations to an individual that has the other one, and observing whether their offspring have the mutant phenotype. If the offspring do not have the mutant phenotype, then the genes are known to be trans, because the offspring have normal copies of each mutant gene on the different functional units which are able to genetically complement each other. If the offspring do have the mutant phenotype, then the genes are known to be cis, because the offspring will always inherit at least one of the mutant genes on the one functional unit, resulting in the mutant phenotype. (09 Oct 1997) |
| 11-cis-retinal | The isomer of retinaldehyde that can combine with opsin to form rhodopsin; it is formed from 11-trans-retinal by retinal isomerase. Synonym: neoretinal b. (05 Mar 2000) |
| 11-cis-retinol | Retinol with cis configuration at the 11-position (carotenoid numbering) or 5'-position (retinol numbering) of the side chain; an intermediate in the vision cycle. Synonym: neoretinene B. (05 Mar 2000) |
| 9-cis-retinol dehydrogenase | <enzyme> Catalyses oxidation of 9-cis-retinol to 9-cis-retinaldehyde; does not catalyze oxidation of all-trans-retinol; genbank u89717 Registry number: EC 1.1.1.- Synonym: retinol dehydrogenase (9-cis) (26 Jun 1999) |
| abscopal effect | A reaction produced following irradiation but occurring outside the zone of actual radiation absorption. (05 Mar 2000) |
| additive effect | <biochemistry, chemistry> An additive effect is the overall biological effect two chemicals acting together and which is the simple sum of the effects of the chemicals acting independently. Compare: antagonism. (15 Jan 1998) |
| adverse effect | This is an abnormal or harmful effect to an organism caused by exposure to a chemical. It is indicated by some result such as death, a change in food or water consumption, altered body and organ weights, altered enzyme levels, or visible illness. An effect may be classed as adverse if it causes functional or anatomical damage, causes irreversible change in the homeostasis of the organism, or increases the susceptibility of the organism to other chemical or biological stress. A non-adverse effect will usually be reversed when the organism is no longer being exposed to the chemical. (09 Oct 1997) |
| Anrep effect | A small transient positive inotropic effect of abrupt increases of systolic aortic and left ventricular pressures related to recovery from transient subendocardial ischemia (e.g., cold pressor test). (05 Mar 2000) |
| antagonistic effect | This is the consequence of one chemical (or group of chemicals) counteracting the effects of another chemical, the opposing chemicals cancel out each other's effects. (09 Oct 1997) |
| Arias-Stella effect | Focal, unusual, decidual changes in endometrial epithelium, consisting of intraluminal budding, and nuclear enlargement and hyperchromatism with cytoplasmic swelling and vacuolation; may be associated with ectopic or uterine pregnancy. Synonym: Arias-Stella effect, Arias-Stella reaction. (05 Mar 2000) |
| Auger effect | <physics> Transition of an electron in an atom from a discrete electronic level to an ionised continuous level with the same energy. Synonym: autoionisation. (13 Jan 1998) |
| autokinetic effect | In psychology, the apparent drifting about of a small, fixed, spot of light which is being observed in a dark room. (05 Mar 2000) |