Search results for "terase"
showing 10 items of 446 documents
Dual enzyme-responsive "turn-on" fluorescence sensing systems based on in situ formation of 7-hydroxy-2-iminocoumarin scaffolds.
2015
A new strategy for the simultaneous fluorogenic detection of two distinct enzyme activities namely hydrolase (amidase or esterase) and reductase is described. This innovative biosensing method is based on the powerful "covalent-assembly" principle that involves in situ synthesis of a fluorophore from a non-fluorescent caged precursor and through domino reactions triggered by the two analytes of interest. To establish this approach, penicillin G acylase (PGA) (or pig liver esterase (PLE)) and nitroreductase (NTR) were chosen as model enzymes, and original bis-O-protected 2,4-dihydroxycinnamonitrile derivatives acting as dual-reactive probes readily convertible to highly fluorescent 7-hydroxy…
Synergistic Platelet Inhibitory Effect of the Phosphodiesterase Inhibitor Piroximone and Iloprost
1992
Platelet activity is regulated through synthesis and degradation of the intracellular second messengers cAMP or cGMP. The antiplatelet effect of the phosphodiesterase (PDE) III inhibitor Piroximone (PIR) was studied in vitro in platelet rich plasma. ADP induced aggregation was inhibited by PIR with an IC50 of 67 +/- 43 microM. The inhibitory effect was time and dose dependent. The antiaggregatory effects in vivo were studied in anaesthetised rats. Reduction of platelet count following injection of 100 micrograms/kg bw collagen was measured after bolus injection of PIR and vehicle. Piroximone bolus 2 mg/kg bw resulted in a 50% inhibition of platelet aggregation in rats. Cyclic AMP levels in …
Construction of Spirooxindole Analogues Engrafted with Indole and Pyrazole Scaffolds as Acetylcholinesterase Inhibitors
2021
Twenty-five new hits of spirooxindole analogs 8a–y engrafted with indole and pyrazole scaffolds were designed and constructed via a [3+2]cycloaddition (32CA) reaction starting from three components: new chalcone-based indole and pyrazole scaffolds 5a–d, substituted isatins 6a–c, and secondary amines 7a–d. The potency of the compounds were assessed in modulating cholinesterase (AChE) activity using Ellman’s method. Compounds 8i and 8y showed the strongest acetylcholine esterase inhibition (AChEI) with IC50 values of 24.1 and 27.8 μM, respectively. Molecular docking was used to study their interaction with the active site of hAChE. peerReviewed
Response of soil phosphatase activities to contamination with two types of tar oil.
2018
Tar oil is a complex mixture of hydrocarbon compounds obtained from high-temperature distillation of coal tar. It has been used for over 100 years from now to protect wood and has been applied to wood products, primary utility poles, and railroad ties by pressure methods. Composition of the tar oil depends on the source and typically consists of 85% polycyclic aromatic hydrocarbons (PAHs), 10% phenolic compounds, and 5% heterocyclic compounds. In this research, we performed the laboratory experiment to compare two types of tar oil: C and GX-Plus, and their effects on P-cycling enzymes (phosphatases) in sandy loam and loamy sand. Tar oil was applied to soil samples at the following doses: 2,…
Current status of phosphodiesterase inhibitors in the treatment of congestive heart failure.
1992
The phosphodiesterase inhibitors have been recognised as potent inotropic and vasodilating drugs. In acute congestive heart failure they increase cardiac output, decrease left pulmonary capillary wedge pressure, and reduce total peripheral resistance with an improvement in loading conditions of the failing heart. Their potency in reversal of symptoms of acute congestive heart failure is quite similar to, or even better than, treatment with intravenous catecholamines and sodium nitroprusside. In chronic congestive heart failure, however, these agents increase mortality and have deleterious effects in the outcome of patients with severe left ventricular dysfunction.
Papaverine enhances the negative inotropic effect of acetylcholine in rat auricles
1978
The negative inotropic effect of acetylcholine in rat left auricles is enhanced in the presence of the phosphodiesterase inhibitor papaverine. This result favours the idea of a cyclic GMP-mediated action of acetylcholine in the heart.
A negative inotropic effect of acetylcholine in the presence of several phosphodiesterase inhibitors.
1981
The phosphodiesterase inhibitors papaverine, theophylline and 3-isobutyl-1-methylxanthine (IBMX) reveal a negative inotropic effect of acetylcholine in cat ventricular heart muscle. This effect in unrelated to beta-adrenoceptor stimulation and possibly mediated by the accumulation of cyclic GMP.
Increased recovery of brain acetylcholinesterase activity in dichlorvos-intoxicated European eels Anguilla anguilla by bath treatment with N-acetylcy…
2003
Organophosphate (OP) pesticides are widely used as antiparasitic chemicals in finfish aquaculture. However, current antidotes cannot be applied to treat intoxicated fish. We showed in previous studies the importance of glutathione (GSH) metabolism in pesticide resistance of the European eel Anguilla anguilla L. The present work studied the effects of the antioxidant and glutathione pro-drug N-acetyl-l-cysteine (NAC) on the recovery of European eels exposed for 96 h to a sublethal concentration (0.17 mg l^-1; 20% of its 96 h LC50) of the OP pesticide dichlorvos (2,2-dichlorovinyl dimethyl phosphate; DDVP). This insecticide and acaricide decreased muscular GSH content and increased oxidised g…
Toxicity of Dimethoate to Some Soil Animal Species in Different Soil Types
1996
Toxicity of dimethoate (insecticide) to an earthworm (Aporrectodea caliginosa tuberculata), a collembola (Folsomia candida), and an enchytraeid worm (Enchytraeus crypticus/variatus) was studied in three different soil types (artificial soil, clayey soil, and humus sandy soil). Parameters measured were survival and biomass change of the earthworms and survival and reproduction of the collembolas and enchytraeids. The degradation of dimethoate was analyzed too. Toxic effects were observed at the concentrations of some mg/kg dry soil. The biomass reduction of the earthworms occurred at lower concentrations than reduction in survival. The collembolas were more susceptible to dimethoate than the…
Relationship between esterase activity and acrinathrin and methiocarb resistance in field populations of western flower thrips, Frankliniella occiden…
2006
The western flower thrips, Frankliniella occidentalis (Pergande), is a serious pest in the south-east of Spain owing to its direct feeding on crops, transmission of the tomato spotted wilt virus and its very high level of resistance to insecticides. Mechanisms of resistance were examined using field populations of F. occidentalis with different susceptibilities to acrinathrin, methiocarb (selective insecticides), endosulfan, metamidophos and deltamethrin (broad-spectrum insecticides). Esterase activity towards alpha-naphthyl acetate and p-nitrophenyl acetate in resistant strains was significantly higher than in the reference strain (MLFOM) for both model substrates. This higher activity was…