| DNA probe | <molecular biology> A small piece of nucleic acid that has been labelled with a radioactive isotope, dye, or enzyme and is used to locate a complementary nucleotide sequence or gene on a DNA molecule. (14 Nov 1997) |
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| DNA probes | Species- or subspecies-specific DNA (including complementary DNA (DNA, complementary), conserved genes, whole chromosomes, or whole genomes) used in hybridization studies in order to identify microorganisms, to measure DNA-DNA homologies, to group subspecies, etc. The DNA probe hybridises with a specific mRNA, if present. Conventional techniques used for testing for the hybridization product include dot blot assays, southern blot assays, and DNA:RNA hybrid-specific antibody tests. Conventional labels for the DNA probe include the radioisotope labels 32p and 125i and the chemical label biotin. The use of DNA probes provides a specific, sensitive, rapid, and inexpensive replacement for cell culture techniques for diagnosing infections. (12 Dec 1998) |
| DNA probes, HLA | DNA probes specific for the human leukocyte antigen genes, which represent the major histocompatibility determinants in humans. The four known loci are designated as a, b, c, and d. Specific antigens are identified by a locus notation and number, e.g., HLA-a11. The inheritance of certain HLA alleles is associated with increased risk for certain diseases (e.g., insulin-dependent diabetes mellitus). (12 Dec 1998) |
| DNA probes, HPV | DNA probes specific for the identification of human papilloma virus. (12 Dec 1998) |
| DNA-directed DNA polymerase | <enzyme> DNA-dependent DNA polymerases found in bacteria, animal and plant cells. During the replication process, these enzymes catalyze the addition of deoxyribonucleotide residues to the end of a DNA strand in the presence of DNA as template-primer. They also possess exonuclease activity and therefore function in DNA repair. Chemical name: Deoxynucleoside-triphosphate:DNA deoxynucleotidyltransferase (DNA-directed) Registry number: EC 2.7.7.7 (12 Dec 1998) |
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| Bowman's probe | A double-ended probe for the lacrimal duct. (05 Mar 2000) |
| radioactive probe | A nucleic acid fragment, labelled by a radioisotope, biotin, etc., that is complementary to a sequence in another nucleic acid (fragment) and that will, by hydrogen binding to the latter, locate or identify it and be detected; a diagnostic technique based on the fact that every species of microbe possesses some unique nucleic acid sequences which differentiate it from all others, and thus can be used as identifying markers or "fingerprints." (05 Mar 2000) |
| magnetic probe | <radiobiology> A conducting coil (sometimes insulated and inserted into the plasma) will have an induced voltage due to changes in the magnetic flux through the coil, and can therefore be used to measure changes in magnetic field strength. Small coils used to measure the local field strength are known as probes. (Other plasma diagnostics using this effect are the Rogowski coil, the voltage loop, and the diamagnetic loop.) Magnetic probes placed outside a toroidal plasma which are used to measure the poloidal magnetic field are also called Mirnov coils. (09 Oct 1997) |
| gene probe | A biomolecule that islabelled with radioactive isotopes or with a fluorescent marker that selectively binds to a specific gene so it can be isolated or identified. (09 Oct 1997) |
| vertebrated probe | A probe made up of a series of short sections hinged together for flexibility in penetrating convoluted tracts. (05 Mar 2000) |
| viral probe | A nucleic acid fragment, labelled by a radioisotope, biotin, etc., that is complementary to a sequence in another nucleic acid (fragment) and that will, by hydrogen binding to the latter, locate or identify it and be detected; a diagnostic technique based on the fact that every species of microbe possesses some unique nucleic acid sequences which differentiate it from all others, and thus can be used as identifying markers or "fingerprints." (05 Mar 2000) |
| periodontal probe | A calibrated instrument used to measure the depth and topography of periodontal pockets. (05 Mar 2000) |
| molecular probe techniques | The use of devices which use detector molecules to detect, investigate, or analyze other molecules, macromolecules, molecular aggregates, or organisms. (12 Dec 1998) |
| multi-locus probe | A probe that hybridizes to anumber of different sites in the genome of an organism. (09 Oct 1997) |
| probe | <molecular biology> General term for a piece of DNA or RNA corresponding to a gene or sequence of interest, that has been labelled either radioactively or with some other detectable molecule, such as biotin, digoxygenin or fluorescein. As stretches of DNA or RNA with complementary sequences will (hybridise), a probe will label viral plaques, bacterial colonies or bands on a gel that contain the gene of interest. See: Northern blots, Southern blots. (18 Nov 1997) |
| probe patency | (of foramen ovale), a term introduced by B.M. Patten to cover incomplete fibrous adhesion of an adequate valvula foraminis ovalis in the postnatal closure of the foramen ovale. (05 Mar 2000) |
| probe-pointed | <surgery> Having a blunt or button-shaped extremity; said of cutting instruments. Source: Websters Dictionary (01 Mar 1998) |
| probe syringe | A syringe with an olive-shaped tip, used in treatment of diseases of the lacrimal passages. (05 Mar 2000) |
| Scanning Probe Microscopy | <technique> Initially called Atomic Force Microscopy, this technique is now more typically termed Scanning Force Microscopy or Scanning Probe Microscopy. This instrument is essentially an extremely high resolution profilometre. A sharp tip, typically fabricated from silicon nitride, is scanned across the surface of a sample at a constant force by three piezoelectric ceramics. The piezoelectric ceramics are computer controlled via a feedback loop which monitors the position of the tip by means of an optical lever. (A laser is focused on the top of the tip support and the beam reflected into a position sensitive detector). The changes in height of the tip are used to form an image as the tip is scanned across the sample. Acronym: SPM (26 Mar 1998) |