(n.) An oily, volatile hydrocarbon, obtained by the distillation of caoutchouc or guttaipercha.
Example Sentences:
(1) The location of the internal trans and cis isoprene units in ficaprenol-11 isolated from Ficus elastica was determined by 13C nuclear magnetic resonance.
(2) An enzymatic comparison with a variety of polyprenol substrates indicates that the solubilized kinase prefers long-chain (C90-95) polyprenols with saturated alpha-isoprene units.
(3) Analysis by mass spectrometry and by nuclear magnetic resonance showed that the molecule is formed by condensation of 10 unsaturated isoprene units and 1 saturated isoprene unit.
(4) The chemical structure of synthetic dolichol-19, which was prepared by the addition of a saturated isoprene unit to the polyprenol-18 isolated from Ginkgo biloba, was confirmed to be identical with that of pig liver dolichol-19.
(5) The number of internal trans isoprene residues in this compound was three in comparison with two such residues in long-chain C95-dolichol.
(6) It was demonstrated that C30-C80-polyprenyl phosphates with unsaturated alpha-isoprene unit were as active as natural acceptor (undecaprenyl phosphate) in this enzymic system.
(7) Hb adducts also accumulated linearly after repeated daily administration of 100 mumol [14C]butadiene or 500 mumol [14C]isoprene per kilogram body wt to mice and rats, respectively, for 3 days.
(8) The relative amount of the metabolites present in blood was highest for low concentrations of inhaled isoprene and for shorter exposure durations.
(9) Three side-chains monocarboxylic acids hydroxylated in allylic positions in the isoprene moiety were also characterized.
(10) Catalytic hydrogenolysis has been used as a means of distinguishing between classes of polyprenyl phosphate sugars which contain saturated alpha-isoprene units from those in which this grouping is allylic.
(11) Two isoprenoids with 9 to 10 isoprene chains (polyprenoids), N-(p-methylbenzyl)decaprenylamine and N-solanesyl-N,N'-bis(3,4-dimethoxybenzyl)ethylenediamine overcame the multidrug resistance almost completely in cultured Chr-24, whereas they only slightly sensitized the parental KB cells to anticancer agents.
(12) This was independent of inhaled isoprene concentration.
(13) The incorporation of radioactive farnesyl pyrophosphate and radioactive geranylnerol and the lack of incorporation of radioactive geranylgeraniol into betulaprenols-6 to -9 demonstrated that they are formed by the cis-additions of isoprene residues to all-trans-farnesyl pyrophosphate.
(14) In brain, spleen, and intestine one-third and in other tissues 10-20% of the total ubiquinone contained 10 isoprene units.
(15) The compound is thus designated MK-8(2H), indicating a menaquinone with eight isoprene units but only seven double bonds in the side chain.
(16) The isoprenoid pattern for dolichol and dolichyl-P, respectively, is modified to longer polyprenols in the two fractions as seen in the percent distribution of the individual isoprenes.
(17) Six differential observations were made: (1) Plastoquinone and ubiquinones, with a side chain of more than two isoprene units, are by far better mediators than their short-chain homologues.
(18) 14CO2 exhalation after the end of the 6-hr exposure was minimal (2%) at the 20 ppm exposure and increased up to 18% at the higher isoprene exposure concentrations.
(19) A biosynthesis of hexahydroprenols by addition of cis-isoprene units to all-trans-geranylgeranyl pyrophosphate, or a dihydro or tetrahydro derivative thereof, is suggested.
(20) A method for the determination of neophytadiene in the total particulate matter of cigarette smoke was developed and applied to test its relationship to isoprene deliveries.
Terpene
Definition:
(n.) Any one of a series of isomeric hydrocarbons of pleasant aromatic odor, occurring especially in coniferous plants and represented by oil of turpentine, but including also certain hydrocarbons found in some essential oils.
Example Sentences:
(1) Cyclic terpenes were selected from the chemical classes of hydrocarbons (e.g., alpha-pinene), alcohols (e.g., alpha-terpineol), ketones (e.g., carvone), and oxides (e.g., 1.8-cineole, ascaridole).
(2) From the unsaponifiable fraction (63 g) of linseed oil (25 kg), two terpenic alcohols were isolated by alumina column, thin-layer, and gas-liquid chromatography.
(3) During growth on oat grain the production of 8-carbon alcohols and 3-methyl-1-butanol was higher and the production of terpenes was lower than during growth on agar substrates.
(4) Derivatives of camphor and terpenes have been identified in this particular river.
(5) The organisms were isolated on, and grew rapidly in, mineral salts medium containing the appropriate terpene substrates as sole carbon sources.
(6) These observations are compared with the results obtained with terpenic molecules which interact with mitochondrial respiration.
(7) The terpenes with hydrogen-bonding ability, however, only enhanced propranolol flux (at a level comparable to n-nonanol).
(8) The terpene PAF receptor antagonist BN52021 inhibited the action of PAF on [Ca2+]i. Voltage-dependent Ca2+ channel blocker, verapamil (200 microM), antagonized the action of PAF on [Ca2+]i as did chelation of extracellular Ca2+.
(9) Bakuchiol [17], a known prenylated phenolic terpene, was also isolated; its activity was not due to toxicity.
(10) The studies on isolated mitochondria showed a series of effects, starting with the disappearance of the respiratory control and deenergization of the organelles and followed by an inhibition of respiration at higher concentrations of the terpene.
(11) To improve oral litholysis: 1) UDCA was combined with the amino acid taurine, 2) CDCA and UDCA were administered in a single bedtime dose, 3) they were combined, each bile acid in half dosage, and 4) they were mixed with terpenes.
(12) The terpenes prolonged nucleation time from 2.8 to 5.8 days (one capsule; P less than 0.05) and to 9.5 days (two capsules; P less than 0.001), respectively; but nucleation did not occur in seven controls.
(13) Samples collected from 50 mL of ambient air at 87 K (liquid argon) are injected without use of a valve into a silica capillary column which is then temperature programmed from -30 degrees C to 180 degrees C. Hydrocarbons (4 to 10 carbons) as well as carbonyl compounds, chlorinated compounds and terpenes can be identified and quantified.
(14) These results support previous findings suggesting that hydroxylation of the terpene portion of the delta 9-THC molecule significantly reduces intraocular pressure lowering activity.
(15) The problems connected with the measurement of hydrocarbons outside urban areas are considerable: The atmospheric mixing ratios of most of the hydrocarbons are very low--from a few ppb down to some ppt; the mixture of hydrocarbons is extremely complex, ranging from light n-alkanes to alkyl benzenes and terpenes; for measurements in remote areas the logistic conditions often restrict the instrumentation which can be used for sample collection or in situ measurements (such as lack of electric power supply, weight restrictions etc.).
(16) Inhibitors included sulfhydryl reactive compounds, terpene epoxides, and pinane derivatives with substituent groups at carbon 3.
(17) However, rat liver microsomal acyl-CoA:retinol acyltransferase activity was inhibited by the terpene ester.
(18) The content of n-isoalkans, isoprenoids, monocycloparaffins, bi-and tricyclic naphthenes, steranes and terpenes, olifines, squalene and other polyenes in sunflower, cotton, soya oils and oilcakes was measured.
(19) The genotoxicity of the terpene beta-myrcene was evaluated in mammalian cells in vitro.
(20) Both are terpenes, which are derived by assembly of isoprene units.