(a.) Sour, sharp, or biting to the taste; tart; having the taste of vinegar: as, acid fruits or liquors. Also fig.: Sour-tempered.
(a.) Of or pertaining to an acid; as, acid reaction.
(n.) A sour substance.
(n.) One of a class of compounds, generally but not always distinguished by their sour taste, solubility in water, and reddening of vegetable blue or violet colors. They are also characterized by the power of destroying the distinctive properties of alkalies or bases, combining with them to form salts, at the same time losing their own peculiar properties. They all contain hydrogen, united with a more negative element or radical, either alone, or more generally with oxygen, and take their names from this negative element or radical. Those which contain no oxygen are sometimes called hydracids in distinction from the others which are called oxygen acids or oxacids.
Example Sentences:
(1) The amino acid sequence deduced from the nucleotide sequence contained both amino- and carboxyl-terminal sequences.
(2) F(420) is photolabile aerobically in neutral and basic solutions, whereas the acid-stable chromophore is not photolabile under these conditions.
(3) The high amino acid levels in the cells suggest that these cells act as inter-organ transporters and reservoirs of amino acids, they have a different role in their handling and metabolism from those of mammals.
(4) If ascorbic acid was omitted from the culture medium, the extensive new connective tissue matrix was not produced.
(5) The interaction of the antibody with both the bacterial and the tissue derived polysialic acids suggests that the conformational epitope critical for the interaction is formed by both classes of compounds.
(6) Arachidic acid was without effect, while linoleic acid and linolenic acid were (on a concentration basis) at least 5-times less active than arachidonic acid.
(7) An unsaturated fatty acid auxotroph of Escherichia coli was grown with a series of cis-octadecenoate isomers in which the location of the double bond varied from positions 3 to 17.
(8) The ability of azelastine to influence antigen-induced contractile responses (Schultz-Dale phenomenon) in isolated tracheal segments of the guinea-pig was investigated and compared with selected antiallergic drugs and inhibitors of arachidonic acid metabolism.
(9) After 4 to 6 hours of recirculation, accumulation of vasoactive amine, 5-hydroxytryptamine, its major metabolite, 5-hydroxyindole acetic acid, and its precursor amino acid, tryptophan were detected.
(10) Spectrophotometric determination of the sulfhydryl content in the animal tissue before (control) and after using 6,6'-Dithiodinicotinic acid is applied.
(11) This death is also dependent on the presence of chloride and is prevented with the non-selective EAA antagonist, kynurenic acid, but is not prevented by QA.
(12) However, four of ten young adult outer arm (relatively sun-exposed) and one of ten young adult inner arm (relatively sun-protected) fibroblasts lines increased their saturation density in response to retinoic acid.
(13) Microionophoretically applied excitatory amino acids induced firing of extracellularly recorded single units in a tissue slice preparation of the mouse cochlear nucleus, and the similarly applied antagonist 2-amino-5-phosphonovalerate (2APV) was demonstrated to be a selective N-methyl-D-aspartate (NMDA) receptor antagonist.
(14) The LD50 of the following metal-binding chelating drugs, EDTA, diethylenetriaminepentaacetic acid (DTPA), hydroxyethylenediaminetriacetic acid (HEDTA), cyclohexanediaminotetraacetic acid (CDTA) and triethylenetetraminehexaacetic acid (TTHA) was evaluated in terms of mortality in rats after intraperitoneal administration and was found to be in the order: CDTA greater than EDTA greater than DTPA greater than TTHA greater than HEDTA.
(15) Estimations of the degree of incorporation of 14C from the radioactive labeled carbohydrate into the glycerol and fatty acid moieties were carried out.
(16) The second amino acid residue influences not only the rate of reaction but also the extent of formation of the product of the Amadori rearrangement, the ketoamine.
(17) Leumorphin is a 29-amino-acid peptide derived from preproenkephalin B. Intracerebroventricular (i.c.v.)
(18) Hepatic lymph flow increased only after ethacrynic acid and mannitol administration.
(19) The subcellular distribution of sialyltransferase and its product of action, sialic acid, was investigated in the undifferentiated cells of the rat intestinal crypts and compared with the pattern observed in the differentiated cells present in the surface epithelium.
(20) A phytochemical investigation of an ethanolic extract of the whole plant of Echites hirsuta (Apocynaceae) resulted in the isolation and identification of the flavonoids naringenin, aromadendrin (dihydrokaempferol), and kaempferol; the coumarin fraxetin; the triterpene ursolic acid; and the sterol glycoside sitosteryl glucoside.
Ester
Definition:
(n.) An ethereal salt, or compound ether, consisting of an organic radical united with the residue of any oxygen acid, organic or inorganic; thus the natural fats are esters of glycerin and the fatty acids, oleic, etc.
Example Sentences:
(1) These effects are similar to those reported for AVP and phorbol esters, activators of protein kinase C. Forskolin and isoproterenol, which induce cAMP accumulation, activated extractable topoisomerase II (maximum 5-15 min after treatment), but not topoisomerase I. Permeable cyclic nucleotide analogs dBcAMP and 8BrcGMP selectively activated extractable topoisomerase II and topoisomerase I activities, respectively.
(2) Preincubation of human neutrophils with recombinant tumor necrosis factor alpha has previously been shown by us to enhance superoxide production of neutrophils in response to the chemotactic peptide formyl-methionyl-leucyl-phenylalanine, and the phorbol ester, phorbol myristate acetate.
(3) Tumor promoting phorbol esters (1-1000 nM) could also inhibit PGE2 stimulated cAMP production dose dependently.
(4) These products were identified to be epimers of 5,12(S)-dihydroxy-eicosatetraenoic acid methyl ester (5,12(S)-diHETE-Me) and epimers of 11,12-diHETE-Me.
(5) Benzyloxycarbonylarginine p-nitrophenyl ester and other activated esters of N-a-sustituted arginine salts may be useful reagents for introduction of trypsin-labile protecting groups into peptide fragments for purpose of polypeptide semi-synthesis.
(6) The immunodetectable PKC level in hypothyroid liver was elevated 7.7-fold, whereas the phorbol-ester binding capacity and the immunodetectable alpha-PKC level were increased 2.4- and 2.6-fold, respectively.
(7) The presence of a previously unreported dipeptide transport mechanism within blood leukocytes and the selective enrichment of the granule enzyme, DPPI, within cytotoxic effector cells of lymphoid or myeloid lineage appear to afford a unique mechanism for the targeting of immunotherapeutic reagents composed of simple dipeptide esters or amides.
(8) Incubation of membrane with DL-Hcys alone (5 X 10(-5) M), the combination of both Ad (5 X 10(-5)) and DL-Hcys (5 X 10(-5)), or S-adenosyl-L-homocysteine (SAH) (1 X 10(-6)) strongly decreased the methyl ester formation.
(9) To this purpose, the formation of DHT has been measured in rat glial cell cultures after different time of exposure to TPA, 4 alpha-Ph, an active and an inactive phorbol ester respectively, and 8-Br-cAMP.
(10) Insulin incubation of plasma membranes pretreated with protease inhibitors (leupeptin, phenylmethylsulfonylfluoride) or with exogenous trypsin, but not chymotrypsin substrates (esters of arginine and tyrosine) yields an inactive supernatant on PDH.
(11) Lymphocyte stimulation by phorbol ester for a short time induces c-fos and c-myc expression, but has no effect on [3H]thymidine incorporation.
(12) The cryptoxanthin esters varied from 5 to 10% of the total carotenoids in Valencia orange juice concentrates and from 10 to 15% of the total carotenoids in Navel orange juice concentrates.
(13) Early in the regression process, cholesterol esters are reduced at least partly by hydrolysis to yield cholesterol, some of which may crystallize and inhibit rapid regression.
(14) The kinetics of the luminescent signal with the different luciferin esters varied significantly, indicating possible differences in the rates of uptake, breakdown and enzyme inhibition.
(15) In comparison to rat pancreas, [D-Phe6]BN-(6-13)ethyl ester, Ac-GRP-(20-26)ethyl ester, [D-Phe6,Cpa14, psi 13-14]BN-(6-14), [Leu14, psi 13-14]BN, and [Leu14, psi 9,10]BN had a 10,000-, 2,940-, 1,425-, 122-, and 4-fold, respectively, weaker affinity for BN receptors.
(16) Enzymatic lability does not, however, play as important a role as lipophilicity in the corneal and conjunctival penetration of cycloalkyl and aryl ester prodrugs.
(17) To determine whether the triadimefon-induced hyperactivity is due to an action on CNS catecholaminergic systems, we evaluated the effects of combined treatment of triadimefon with either the tyrosine hydroxylase inhibitor d,l-alpha-methyl-p-tyrosine methyl ester HCl (alpha MPT) or the amine depletor reserpine.
(18) Growth of C. albicans in the presence of AGE affected the yeast lipid in a number of ways: the total lipid content was decreased; garlic-grown yeasts had a higher level of phosphatidylserines and a lower level of phosphatidylcholines; in addition to free sterols and sterol esters, C. albicans accumulated esterified steryl glycosides; the concentration of palmitic acid (16:0) and oleic acid (18:1) increased and that of linoleic acid (18:2) and linolenic acid (18:3) decreased.
(19) In comparison with native counterparts, the in vitro-formed LDL2 and HDL + VHDL were characterized by lower levels of triglyceride and cholesterol ester and higher levels of free cholesterol and lipid phosphorus.
(20) Several histidine derivatives are not susceptible to the enzyme but do inhibit the enzyme activity competitively; the most effective inhibitors are L-histidine methyl ester (Ki = 3.66 mM) and beta-imidazole lactic acid (Ki = 3.84 mM).