(n.) A impure earthy ore of iron or a ferruginous clay, usually red (hematite) or yellow (limonite), -- used as a pigment in making paints, etc. The name is also applied to clays of other colors.
(n.) A metallic oxide occurring in earthy form; as, tungstic ocher or tungstite.
(n.) See Ocher.
Example Sentences:
(1) Allelic complementation was not observed, despite testing of a large number of allele pairs, and alleles suppressible by the ochre suppressor SUP11 were absent from a sample of 48 spontaneous mutants and occurred infrequently (7%) among a sample of ultraviolet-induced mutants.
(2) Amber (UAG) and ochre (UAA) mutations are suppressed whereas UGA is not suppressed.
(3) Introduction of an ochre nonsense codon into the reading frame of the leader peptide sequence leads to considerable reduction of the basal expression and loss of inducibility of the cat gene.
(4) The first position of anticodon is 2'-O-methyluridine (Um), forming UmUA as the anticodon, which presumably recognizes the ochre termination codon UAA.
(5) Oligonucleotide-directed mutagenesis was used to generate amber, ochre and opal suppressors from cloned Arabidopsis and Nicotiana tRNA(Tyr) genes.
(6) The activities are present in yeast mutants which have greatly reduced levels of the three major vacuole-associated proteases (A, B and C) or which carry an ochre mutation in the major neutral protease (B).
(7) Mutants containing an ochre mutation in any essential yeast gene give rise to nonsectoring, white colonies, since cell growth is dependent on the presence of the plasmid-borne suppressor.
(8) Amber and ochre suppressor mutations in Salmonella typhimurium were selected.
(9) The nonsense mutants of S. pombe have been classified according to their suppressibility by defined opal and ochre suppressors into a class of efficiently suppressed opal and a class of inefficiency suppressed ochre mutants.
(10) Patterns of reversion produced by ciprofloxacin, enoxacin and ofloxacin in Salmonella typhimurium strains carrying the hisG428 ochre mutation have been studied.
(11) These replacements are consistent with a chain-terminating codon in am(17) of either the amber (UAG) or the ochre type (UAA), but are inconsistent with UGA.
(12) Allosuppressor (sal) mutations enhance the efficiency of the yeast ochre suppressor SUQ5 and define five unlinked loci, SAL1-SAL5.
(13) Using site-specific mutagenesis, we constructed five more efficient variants of tRNA(Glu)-Suoc, an extremely inefficient ochre suppressor.
(14) The opal suppressor form shows moderate suppressor activity when the gene is introduced on this vector, however, the ochre suppressor form exhibits no detectable biological activity regardless of gene copy number.
(15) 4-nitroquinoline-1-oxide (NQO) induces high frequencies of intragenic revertants of amber (UAG) but not ochre (UAA) mutants of yeast.
(16) Genetic recombination was assayed by measuring beta-galactosidase produced after recombination between two noncomplementing lacZ ochre alleles.
(17) The growth patterns of nonsense mutants of RNA (GA and f2) and DNA (lambda and T4) phages suggested that KO1 carried an amber, but not ochre or opal suppressors.
(18) Of 313 motility-deficient mutants isolated from an LT2 his(amber) strain fixed in phase 1 by gene vh2(-), 25 regained motility when amber or ochre suppressors were introduced, in F' factors or by transduction.
(19) The plasmid also increased frequency of UV-induced reversion to His+ in all tested his point mutants (wild type for UV sensitivity), including amber, ochre, UGA, missense, and frame-shift mutants.
(20) The results demonstrate that an ochre suppressor mutant of Escherichia coli K-12 produces abnormal 30S ribosomes.
Silica
Definition:
(n.) Silicon dioxide, SiO/. It constitutes ordinary quartz (also opal and tridymite), and is artifically prepared as a very fine, white, tasteless, inodorous powder.
Example Sentences:
(1) We have previously shown that intratracheally instilled silica (quartz) produces both morphologic evidence of emphysema and small-airway changes, and functional evidence of airflow obstruction.
(2) In the German Democratic Republic, patients with scleroderma and history of long term silica exposure are recognized as patients with occupational disease even though pneumoconiosis is not clearly demonstrated on X-ray film.
(3) Human gingival fibroblasts were allowed to attach and spread on bio-glasses for 1-72 h. Unreactive silica glass and cell culture polystyrene served as controls.
(4) The ADAM derivative of carnitine was separated from decomposition products of the reagent and related compounds such as amino acid derivatives on a silica gel column eluted with methanol-5% aqueous SDS-phosphoric acid (990:10:1).
(5) The deactivated columns had the residual silanols on the silica gel chemically inactivated to reduce the interaction with basic groups or analytes.
(6) We have investigated some of the factors which affect the retention times of these substances in reversed-phase HPLC on columns of 5-micron octadecylsilyl silica.
(7) The corresponding hydrides, mono-n-butyltin hydride, di-n-butyltin hydride, tri-n-butyltin hydride, monophenyltin hydride, diphenyltin hydride triphenyltin hydride, are detected by electron-capture gas chromatography after clean-up by silica gel column chromatography.
(8) The length of the hydrocarbon chains of the surface-modified silica supports had no significant influence on the selectivity.
(9) A novel type of ion exchanger was prepared by multipoint covalent binding of polystyrene chains onto the surface of porous silica followed by polymer-analogous modification of the bonded layer.
(10) The analytes were rapidly separated on an affinity column packed with phenylboronate-bonded silica.
(11) Using thin layer chromatography on fluorescent silica gel plates, 5 indoles were identified and 6 unknown substances isolated from the pineal incubate and from both extracts.
(12) Our results clearly demonstrate that capillary GC analysis of amino acids using fused silica bonded-phase columns provides data with good precision and in general excellent agreement with ion-exchange analyses.
(13) Free haem itself was bound to the silica column but could be released by globin.
(14) The methanol-ammonia (20:1) and chloroform-methanol-ammonia (2:2:1) systems, used with silica-gel plates, are the most promising for rapid preliminary screening of tuna fish extracts for histamine.
(15) The presence of Ca2+ in silica gel is responsible for this improved yield of prostaglandin as the divalent metal ion stabilized prostaglandin synthetase activity in a remarkable way.
(16) Silica accumulated linearly in the mediastinal lymph nodes and thymus for several months after cessation of exposure, while negligible amounts were found in kidney, spleen, liver, and blood.
(17) Methods employing electroosmotic flow in an untreated silica capillary were found to provide, at best, only partial resolution of the 23 fragments in a 1-kbp DNA ladder.
(18) The galactose lipid was isolated by column chromatography on DEAE-cellulose and silica gel.
(19) Adsorption experiments were performed by combining virus and silica in 0.1-ionic-strength buffers of pH 4.0, 6.4, and 8.5.
(20) The extracts are analyzed via a gas chromatograph equipped with a DB-1301 widebore fused-silica capillary column and an electron capture detector.