| recognition factors | Factors which effect "recognition" of target antigens by polymorphonuclear leukocytes; apparently the Fc portion of antibody molecules and the activated third component of complement (C3), for both of which phagocytes have receptor sites. (05 Mar 2000) |
|---|---|
| recognition sequence | A nucleotide sequence --typically composed of 4, 6, or 8nucleotides -- that is recognised by a restriction endonuclease. Type II enzymes cut (and theircorresponding modification enzymes methylate) within or very near the recognition sequence. (09 Oct 1997) |
| recognition time | The interval between the application of a stimulus and the recognition of its nature. (05 Mar 2000) |
| pattern recognition | In information retrieval, machine-sensing or identification of visible patterns (shapes, forms, and configurations). (harrod's librarians' glossary, 7th ed) (12 Dec 1998) |
| pattern recognition, visual | Visually perceived characters, shapes, displays, or designs. (12 Dec 1998) |
| cell recognition | <cell biology> Interaction between cells that is possibly dependent upon specific adhesion. Since the mechanism is not entirely clear in most cases, the term should be used with caution. (26 Mar 1998) |
| signal recognition particle | A complex between a 7S RNA and six proteins. SRP binds to the nascent polypeptide chain of eukaryotic proteins with a signal sequence and halts further translation until the ribosome becomes associated with the rough endoplasmic reticulum. One of the SRP proteins (srp54) binds GTP and in association with 7SRNA and srp19 has GTPase activity. (18 Nov 1997) |
| signal recognition particle receptor | Receptor for the signal recognition particle (SRP) found in the membrane of the endoplasmic reticulum. Also called docking protein. Heterodimeric, both protomers having GTP binding capacity, though dissimilar binding sites. Not until the complex of SRP, ribosome, message and nascent polypeptide chain binds to the SRP receptor is the block to further chain elongation released and concurrently the SRP is released, leaving the ribosome attached to the endoplasmic reticulum membrane. Cotranslational transport of the polypeptide delivers it into the lumen of the ER. (18 Nov 1997) |
| dual recognition hypothesis | An outmoded hypothesis that is known to be incorrect now that the structure of the T-cell receptor is known. The proposal was that viral (and some chemical) antigens were recognised in association with histocompatibility antigens by separate receptors on the T-cell. The generation of cytotoxic T-cells was by association with Class I MHC antigens, of T helper cells by association with Class II MHC antigens. See: altered self hypothesis. (18 Nov 1997) |
| aponeurosis of origin | A tendinous expansion serving as the attachment of origin of a broad muscle. (05 Mar 2000) |
| replication origin | A unique DNA sequence of a replicon at which DNA replication is initiated and proceeds bidirectionally or unidirectionally. It contains the sites where the first separation of the complementary strands occurs, a primer RNA is synthesised, and the switch from primer RNA to DNA synthesis takes place. (rieger et al., glossary of genetics: classical and molecular, 5th ed) (12 Dec 1998) |
| centers of origin | <agriculture> Usually the location in the world where the oldest cultivation of a particular crop has been identified. (09 Oct 1997) |
| nuclei of origin | Collections of motor neurons (forming a continuous column in the spinal cord, discontinuous in the medulla and pons) giving origin to the spinal and cranial motor nerves. Synonym: nuclei originis, motor nuclei. (05 Mar 2000) |
| duck embryo origin vaccine | See: rabies vaccine. (05 Mar 2000) |
| origin | 1. The first existence or beginning of anything; the birth. "This mixed system of opinion and sentiment had its origin in the ancient chivalry." (Burke) 2. That from which anything primarily proceeds; the fountain; the spring; the cause; the occasion. 3. <anatomy> The point of attachment or end of a muscle which is fixed during contraction; in contradistinction to insertion. <mathematics> Origin of coordinate axes, the point where the axes intersect. See Note under Ordinate. Synonym: Commencement, rise, source, spring, fountain, derivation, cause, root, foundation. Origin, Source. Origin denotes the rise or commencement of a thing; source presents itself under the image of a fountain flowing forth in a continuous stream of influences. The origin of moral evil has been much disputed, but no one can doubt that it is the source of most of the calamities of our race. "I think he would have set out just as he did, with the origin of ideas the proper starting point of a grammarian, who is to treat of their signs." (Tooke) "Famous Greece, That source of art and cultivated thought Which they to Rome, and Romans hither, brought." (Waller) Origin: F. Origine, L. Origo, -iginis, fr. Oriri to rise, become visible; akin to Gr. To stir up, rouse, Skr. R, and perh. To E. Run. Source: Websters Dictionary (01 Mar 1998) |