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Sample records for modulates acetylcholinesterase activity

  1. Acetylcholinesterase modulates presenilin-1 levels and γ-secretase activity.

    PubMed

    Campanari, Maria-Letizia; García-Ayllón, María-Salud; Belbin, Olivia; Galcerán, Joan; Lleó, Alberto; Sáez-Valero, Javier

    2014-01-01

    The cholinergic enzyme acetylcholinesterase (AChE) and the catalytic component of the γ-secretase complex, presenilin-1 (PS1), are known to interact. In this study, we investigate the consequences of AChE-PS1 interactions, particularly the influence of AChE in PS1 levels and γ-secretase activity. PS1 is able to co-immunoprecipitate all AChE variants (AChE-R and AChE-T) and molecular forms (tetramers and light subunits) present in the human brain. Overexpression of AChE-R or AChE-T, or their respective inactive mutants, all trigger an increase in PS1 protein levels. The AChE species capable of triggering the biggest increase in PS1 levels is a complex of AChE with the membrane anchoring subunit proline-rich membrane anchor (PRiMA), which restricts the localization of the resulting AChE tetramer to the outer plasma membrane. Incubation of cultured cells with soluble AChE demonstrates that AChE is able to increase PS1 at both the protein and transcript levels. However, the increase of PS1 caused by soluble AChE is accompanied by a decrease in γ-secretase activity as shown by the reduction of the processing of the amyloid-β protein precursor. This inhibitory effect of AChE on γ-secretase activity was also demonstrated by directly assessing accumulation of CTF-AβPP in cell-free membrane preparations incubated with AChE. Our data suggest that AChE may function as an inhibitor of γ-secretase activity. PMID:24699279

  2. Dose dependence of acetylcholinesterase activity in neuroblastoma cells exposed to modulated radio-frequency electromagnetic radiation.

    PubMed

    Dutta, S K; Das, K; Ghosh, B; Blackman, C F

    1992-01-01

    Radio-frequency electromagnetic radiation (RFR) at 915 and 147 MHz, when sinusoidally amplitude modulated (AM) at 16 Hz, has been shown to enhance release of calcium ions from neuroblastoma cells in culture. The dose-response relation is unusual, consisting of two power-density "windows" in which enhanced efflux occurs, separated by power-density regions in which no effect is observed. To explore the physiological importance of these findings, we have examined the impact of RFR exposure on a membrane-bound enzyme, acetylcholinesterase (AChE), which is intimately involved with the acetylcholine (ACh) neurotransmitter system. Neuroblastoma cells (NG108), exposed for 30 min to 147-MHz radiation, AM at 16 Hz, demonstrated enhanced AChE activity, as assayed by a procedure using 14C-labeled ACh. Enhanced activity was observed within a time window between 7.0 and 7.5 h after the cells were plated and only when the exposure occurred at power densities identified in a previous report as being effective for altering the release of calcium ions. Thus RFR affects both calcium-ion release and AChE activity in nervous system-derived cells in culture in a common dose-dependent manner. PMID:1510740

  3. Dietary supplementation with fermented legumes modulate hyperglycemia and acetylcholinesterase activities in Streptozotocin-induced diabetes.

    PubMed

    Ademiluyi, Adedayo O; Oboh, Ganiyu; Boligon, Aline A; Athayde, Margareth L

    2015-12-01

    The study investigated the hypoglycemic and anticholinesterase activities of some fermented legumes (bambara groundnut and locust bean) in Streptozotocin (STZ)-induced diabetic rats. The rats were made diabetic by intraperitoneal administration of STZ (35mg/kg b.w.) and were fed diets containing fermented legumes (10% inclusion) for 14 days. The effect of the diets on blood glucose, pancreatic glutathione peroxidase (GPx) activity, reduced glutathione (GSH) and malondialdehyde (MDA) contents, α-amylase, intestinal α-glucosidase and acetylcholinesterase activities were studied. Significant (P<0.05) increase in blood glucose, pancreatic MDA, α-amylase, intestinal α-glucosidase and acetylcholinesterase activities with concomitant decrease in pancreatic GPx and GSH contents were observed in diabetic rats. However, this trend was reversed in rats fed fermented legumes supplemented diets for 14 days. The HPLC-DAD finger printing revealed the presence of gallic acid, catechin, caffeic acid, epicatechin, rutin, isoquercitrin, quercitrin, quercetin and kaempferol as the dominant phenolic compounds of the fermented legumes. However, possible contributing role of some bioactive peptides could not be ruled out. Hence, the hypoglycemic and antiacetylcholinesterase activities of the fermented legume condiments could be attributed to their constituent phytochemicals. PMID:26349771

  4. Acrylonitrile has Distinct Hormetic Effects on Acetyl-Cholinesterase Activity in Mouse Brain and Blood that are Modulated by Ethanol.

    PubMed

    Yuanqing, He; Suhua, Wang; Guangwei, Xing; Chunlan, Ren; Hai, Qian; Wenrong, Xu; Rongzhu, Lu; Aschner, Michael; Milatovic, Dejan

    2013-01-01

    Acrylonitrile(AN) is a neurotoxin both in animals and humans, but its effects on acetylcholinesterase (AChE) activity remain controversial. This study aimed to determine the dose-response effects of AN on AChE activity and the modulatory role of ethanol pre-treatment. A total of 144 Kunming mice were randomly divided into 18 groups: nine groups received 5% ethanol in their drinking water, and the remaining nine groups received regular tap water. One week later, both the ethanol and tap water only groups were given an intraperitoneal injection of AN at the following doses: 0 (control), 0.156, 0.3125, 0.625, 1.25, 2.5, 5, 10 or 20 mg AN/kg body weight. AChE activity was determined on whole blood and brain 24 h later. Blood AChE activity was higher in AN-injected mice than in controls at all doses. AChE activity in blood increased in a dose-dependent manner, peaking at 0.156 mg/kg, after which a gradual decrease ensued, displaying a β-typed dose-response relationship. In contrast, brain AChE activity, following a single AN injection, was consistently lower than in control mice, and continued to fall up to a dose of 0.313 mg/kg, and thereafter increased gradually with higher doses. Mice receiving a 20 mg/kg dose of AN exhibited AChE brain activity indistinguishable from that of control mice, demonstrating a typical U-typed dose-response relationship. The activity of AChE in the blood and brain of the AN + ethanol-treated groups displayed a shift to the right, and the magnitude of the decrease in AChE activity induced by AN was attenuated relative to the AN-only group. These results suggest that AN affects AChE activity in both mouse blood and brain in a hormetic manner. Pretreatment with ethanol modifies the effect of AN on AChE, indicating that parent AN has a more prominent role than its metabolites in modulating enzyme activity. PMID:23550232

  5. DOSE DEPENDENCE OF ACETYLCHOLINESTERASE ACTIVITY IN NEUROBLASTOMA CELLS EXPOSED TO MODULATED RADIOFREQUENCY RADIATION

    EPA Science Inventory

    Radiofrequency radiation (RFR) at 915 and at 147 MHz, when sinusoidally amplitude modulated (AM) at 16 Hz, has been shown to enhance release of calcium ions from neuroblastoma cells in culture. he dose response is unusual, consisting of two power density 'windows' in which enhanc...

  6. Centrophenoxine activates acetylcholinesterase activity in hippocampus of aged rats.

    PubMed

    Sharma, D; Singh, R

    1995-05-01

    Age-related changes in the acetylcholinesterase activity were measured in the hippocampus, brain stem and cerebellum of rats (aged 4, 8, 16 and 24 months). The age-dependent decrease in the enzyme activity first appeared in the hippocampus; the brain stem was affected later while the cerebellum remained unaffected. Centrophenoxine, usually considered as an ageing reversal drug and also regarded as a neuroenergeticum in human therapy, increased the acetylcholinesterase activity in the hippocampus of aged rats, the activity was also elevated in the brain stem but no in the cerebellum. The acetylcholinesterase-stimulating influence of the drug is likely to be implicated in the pharmacological reversal of the age related decline of the cholinergic system. This effect of the drug may also mediate its effects on cognitive and neuronal synaptic functions. PMID:7558197

  7. Acetylcholinesterase activity in chronic renal failure.

    PubMed

    Prall, Y G; Gambhir, K K; Cruz, I A; Blassingale, J; Ampy, F R

    2000-01-21

    Twenty healthy subjects and 39 Chronic Renal Failure patients (CRF-patients) maintained on chronic hemodialysis were used in this investigation to study the changes in acetylcholinesterase (AChE) activity of red blood cells (RBCs). The CRF-patients were all undergoing hemodialysis treatment. AChE activity from the CRF-patients was determined before and after dialysis. An additional objective was to study the effect of chronic renal failure on human red blood cell aging. Blood samples were drawn from controls and CRF-patients in tubes containing EDTA or sodium heparin as an anticoagulant. Red blood cells were purified to avoid interference with monocytes, reticulocytes and leukocytes. The purified RBCs were subfractionated into young (y) (1.08-1.09), mid (m) (1.09-1.11) and old (o) (1.11-1.12) percoll density (g/mL) fractions using a discontinous percoll gradient. The mean +/- SD AChE per gram hemoglobin (U/g Hgb) activities in whole blood (WB), purified human red blood cells (PRBCs), young human red blood cells (y-RBCs), mid age human red blood cells (m-RBCs) and old human red blood cells (o-RBCs) in CRF-patients were 31.2+/-3.43, 29.3+/-3.26, 30.4+/-3.91, 25.1+/-5.25, 17.1+/-6.02 in females and 29.8+/-5.39, 28.8+/-5.29, 28.7+/-5.29, 23.7+/-5.39 and 16.0+/-5.60 in males. AChE activity from CRF-patients were higher than that found in the control subjects. The aging of human RBCs in both the controls and CRF-patients showed a progressive reduction in AChE activity. AChE activity of RBCs from female CRF-patients were significantly higher (p < 0.05) than that of the female control subjects. The RBCs isolated from male CRF-patients showed a higher AChE activity than control males, but a significant difference was only observed with the mid-age-cells. These studies further indicate that AChE activity remained insignificantly different in the various density based age subfractions of RBCs of both CRF-patients and controls. PMID:10698358

  8. Antioxidative/acetylcholinesterase inhibitory activity of some Asteraceae plants.

    PubMed

    Mekinić, Ivana Generalić; Burcul, Franko; Blazević, Ivica; Skroza, Danijela; Kerum, Daniela; Katalinić, Visnja

    2013-04-01

    The extracts obtained by 80% EtOH from some Asteraceae plants (Calendula officinalis, Inula helenium, Arctium lappa, Artemisia absinthium and Achillea millefolium) were studied. Rosmarinic acid, one of the main compounds identified in all extracts, was determined quantitatively by using HPLC. In addition, spectrophotometric methods were evaluated as an alternative for rosmarinic acid content determination. Total phenolic content was also established for all extracts. A. millefolium extract was found to have the highest content of rosmarinic acid as well as total phenols. All extracts were tested for antioxidant and acetylcholinesterase inhibitory activity. A. millefolium was shown to possess the best antioxidant activity (for all tested methods) as well as acetylcholinesterase inhibitory activity. Highly positive linear relationships were obtained between antioxidant/acetylcholinesterase inhibitory activity and the determined rosmarinic acid content indicating its significance for the observed activities. PMID:23738456

  9. Lower Acetylcholinesterase Activity among Children Living with Flower Plantation Workers

    PubMed Central

    Suarez-Lopez, Jose R.; Jacobs, David R.; Himes, John H.; Alexander, Bruce H.; Lazovich, DeAnn; Gunnar, Megan

    2012-01-01

    BACKGROUND Children of workers exposed to pesticides are at risk of secondary pesticide exposure. We evaluated the potential for lower acetylcholinesterase activity in children cohabiting with fresh-cut flower plantation workers, which would be expected from organophosphate and carbamate insecticide exposure. Parental home surveys were performed and acetylcholinesterase activity was measured in 277 children aged 4–9 years in the study of Secondary Exposure to Pesticides among Infants, Children and Adolescents (ESPINA). Participants lived in a rural county in Ecuador with substantial flower plantation activity. RESULTS Mean acetylcholinesterase activity was 3.14 U/ml, standard deviation (SD): 0.49. It was lower by 0.09 U/ml (95% confidence interval (CI) −0.19, −0.001) in children of flower workers (57% of participants) than non-flower workers’ children, after adjustment for gender, age, height-for-age, hemoglobin concentration, income, pesticide use within household lot, pesticide use by contiguous neighbors, examination date and residence distance to nearest flower plantation. Using a 4 level polychotomous acetylcholinesterase activity dependent variable, flower worker cohabitation (vs. not) had odds ratio 3.39 (95% CI 1.19, 9.64) for being <15th percentile compared to the highest tertile. Children cohabitating for ≥5 years (vs. never) had OR of 4.11 (95% CI: 1.17, 14.38) of AChE activity within <15th percentile compared to the highest tertile. CONCLUSIONS Cohabitation with a flower worker was related to lower acetylcholinesterase activity in children. This supports the hypothesis that the amount of take-home pesticides from flower workers suffices to decrease acetylcholinesterase activity, with lower activity associated with longer exposure. PMID:22405996

  10. Inhibition of acetylcholinesterase activity by essential oil from Citrus paradisi.

    PubMed

    Miyazawa, M; Tougo, H; Ishihara, M

    2001-01-01

    Inhibition of acetylcholinesterase (AChE) activity by essential oils of Citrus paradisi (grapefruit pink in USA) was studied. Inhibition of AChE was measured by the colorimetric method. Nootkatone and auraptene were isolated from C. paradisi oil and showed 17-24% inhibition of AChE activity at the concentration of 1.62 microg/mL. PMID:11858553

  11. L-tyrosine administration increases acetylcholinesterase activity in rats.

    PubMed

    Ferreira, Gabriela K; Carvalho-Silva, Milena; Gonçalves, Cinara L; Vieira, Júlia S; Scaini, Giselli; Ghedim, Fernando V; Deroza, Pedro F; Zugno, Alexandra I; Pereira, Talita C B; Oliveira, Giovanna M T; Kist, Luiza W; Bogo, Maurício R; Schuck, Patrícia F; Ferreira, Gustavo C; Streck, Emilio L

    2012-12-01

    Tyrosinemia is a rare genetic disease caused by mutations on genes that codify enzymes responsible for tyrosine metabolism. Considering that tyrosinemics patients usually present symptoms associated with central nervous system alterations that ranges from slight decreases in intelligence to severe mental retardation, we decided to investigate whether acute and chronic administration of L-tyrosine in rats would affect acetylcholinesterase mRNA expression and enzymatic activity during their development. In our acute protocol, Wistar rats (10 and 30 days old) were killed one hour after a single intraperitoneal L-tyrosine injection (500 mg/kg) or saline. Chronic administration consisted of L-tyrosine (500 mg/kg) or saline injections 12 h apart for 24 days in Wistar rats (7 days old) and rats were killed 12 h after last injection. Acetylcholinesterase activity was measured by Ellman's method and acetylcholinesterase expression was carried out by a semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) assay. We observed that acute (10 and 30 days old rats) and chronic L-tyrosine administration increased acetylcholinesterase activity in serum and all tested brain areas (hippocampus, striatum and cerebral cortex) when compared to control group. Moreover, there was a significant decrease in mRNA levels of acetylcholinesterase in hippocampus was observed after acute protocol (10 and 30 days old rats) and in striatum after chronic protocol. In case these alterations also occur in the brain of the patients, our results may explain, at least in part, the neurological sequelae associated with high plasma concentrations of tyrosine seen in patients affected by tyrosinemia type II. PMID:23046746

  12. Inhibitory effect of some natural and semisynthetic phenolic lipids upon acetylcholinesterase activity.

    PubMed

    Stasiuk, Maria; Bartosiewicz, Dominika; Kozubek, Arkadiusz

    2008-06-01

    The effect of phenolic lipids isolated from rye grains and cashew nut shell liquid (CNSL) from Anacardium occidentale and their semisynthetic derivatives on erythrocyte ghost's acetylcholinesterase activity was studied. It has been shown that all tested compounds decreased the enzymatic activity of acetylcholinesterase. This effect depends on the type of studied compounds. Three of them completely inhibit acetylcholinesterase activity at the micromolar concentration. PMID:26065763

  13. Inhibition of acetylcholinesterase activity in brain and behavioral analysis in adult rats after chronic administration of fenproporex.

    PubMed

    Rezin, Gislaine T; Scaini, Giselli; Ferreira, Gabriela K; Cardoso, Mariane R; Gonçalves, Cinara L; Constantino, Larissa S; Deroza, Pedro F; Ghedim, Fernando V; Valvassori, Samira S; Resende, Wilson R; Quevedo, João; Zugno, Alexandra I; Streck, Emilio L

    2012-12-01

    Fenproporex is an amphetamine-based anorectic and it is rapidly converted in vivo into amphetamine. It elevates the levels of extracellular dopamine in the brain. Acetylcholinesterase is a regulatory enzyme which is involved in cholinergic synapses and may indirectly modulate the release of dopamine. Thus, we investigated whether the effects of chronic administration of fenproporex in adult rats alters acquisition and retention of avoidance memory and acetylcholinesterase activity. Adult male Wistar rats received repeated (14 days) intraperitoneal injection of vehicle or fenproporex (6.25, 12.5 or 25 mg/kg i.p.). For behavioral assessment, animals were submitted to inhibitory avoidance (IA) tasks and continuous multiple trials step-down inhibitory avoidance (CMIA). Acetylcholinesterase activity was measured in the prefrontal cortex, hippocampus, hypothalamus and striatum. The administration of fenproporex (6.25, 12.5 and 25 mg/kg) did not induce impairment in short and long-term IA or CMIA retention memory in rats. In addition, longer periods of exposure to fenproporex administration decreased acetylcholinesterase activity in prefrontal cortex and striatum of rats, but no alteration was verified in the hippocampus and hypothalamus. In conclusion, the present study showed that chronic fenproporex administration decreased acetylcholinesterase activity in the rat brain. However, longer periods of exposure to fenproporex did not produce impairment in short and long-term IA or CMIA retention memory in rats. PMID:22832793

  14. Synthesis and anti-acetylcholinesterase activity of scopoletin derivatives.

    PubMed

    Khunnawutmanotham, Nisachon; Chimnoi, Nitirat; Saparpakorn, Patchreenart; Techasakul, Supanna

    2016-04-01

    A series of scopoletin derivatives incorporated with the pyridinium moiety was synthesized and evaluated for their acetylcholinesterase (AChE) inhibitory activity by the colorimetric Ellman's method. A 2-fluorobenzylpyridinium derivative was the most potent among the tested compounds, with an IC50 value of 0.215±0.015μM, which was greatly improved from that of scopoletin. Docking studies revealed that the scopoletin portion of the mentioned compound was bound to the peripheral anionic site of the AChE, whereas the N-benzylpyridinium residue to the catalytic anionic site. PMID:26943478

  15. Quantitative structure-activity relationships for organophosphates binding to acetylcholinesterase.

    PubMed

    Ruark, Christopher D; Hack, C Eric; Robinson, Peter J; Anderson, Paul E; Gearhart, Jeffery M

    2013-02-01

    Organophosphates are a group of pesticides and chemical warfare nerve agents that inhibit acetylcholinesterase, the enzyme responsible for hydrolysis of the excitatory neurotransmitter acetylcholine. Numerous structural variants exist for this chemical class, and data regarding their toxicity can be difficult to obtain in a timely fashion. At the same time, their use as pesticides and military weapons is widespread, which presents a major concern and challenge in evaluating human toxicity. To address this concern, a quantitative structure-activity relationship (QSAR) was developed to predict pentavalent organophosphate oxon human acetylcholinesterase bimolecular rate constants. A database of 278 three-dimensional structures and their bimolecular rates was developed from 15 peer-reviewed publications. A database of simplified molecular input line entry notations and their respective acetylcholinesterase bimolecular rate constants are listed in Supplementary Material, Table I. The database was quite diverse, spanning 7 log units of activity. In order to describe their structure, 675 molecular descriptors were calculated using AMPAC 8.0 and CODESSA 2.7.10. Orthogonal projection to latent structures regression, bootstrap leave-random-many-out cross-validation and y-randomization were used to develop an externally validated consensus QSAR model. The domain of applicability was assessed by the William's plot. Six external compounds were outside the warning leverage indicating potential model extrapolation. A number of compounds had residuals >2 or <-2, indicating potential outliers or activity cliffs. The results show that the HOMO-LUMO energy gap contributed most significantly to the binding affinity. A mean training R (2) of 0.80, a mean test set R (2) of 0.76 and a consensus external test set R (2) of 0.66 were achieved using the QSAR. The training and external test set RMSE values were found to be 0.76 and 0.88. The results suggest that this QSAR model can be used in

  16. Induction of plasma acetylcholinesterase activity in mice challenged with organophosphorus poisons

    SciTech Connect

    Duysen, Ellen G.; Lockridge, Oksana

    2011-09-01

    The restoration of plasma acetylcholinesterase activity in mice following inhibition by organophosphorus pesticides and nerve agents has been attributed to synthesis of new enzyme. It is generally assumed that activity levels return to normal, are stable and do not exceed the normal level. We have observed over the past 10 years that recovery of acetylcholinesterase activity levels in mice treated with organophosphorus agents (OP) exceeds pretreatment levels and remains elevated for up to 2 months. The most dramatic case was in mice treated with tri-cresyl phosphate and tri-ortho-cresyl phosphate, where plasma acetylcholinesterase activity rebounded to a level 250% higher than the pretreatment activity. The present report summarizes our observations on plasma acetylcholinesterase activity in mice treated with chlorpyrifos, chlorpyrifos oxon, diazinon, tri-ortho-cresyl phosphate, tri-cresyl phosphate, tabun thiocholine, parathion, dichlorvos, and diisopropylfluorophosphate. We have developed a hypothesis to explain the excess acetylcholinesterase activity, based on published observations. We hypothesize that acetylcholinesterase activity is induced when cells undergo apoptosis and that consequently there is a rise in the level of plasma acetylcholinesterase. - Highlights: > Acetylcholinesterase activity is induced by organophosphorus agents. > AChE induction is related to apoptosis. > Induction of AChE activity by OP is independent of BChE.

  17. Aquagenic pruritus. Water-induced activation of acetylcholinesterase.

    PubMed

    Bircher, A J; Meier-Ruge, W

    1988-01-01

    Four patients with aquagenic pruritus (AP), one patient with polycythemia rubra vera, one patient with cold urticaria, and three normal control volunteers were studied to better understand the pathophysiology of water-induced itching. Punch biopsy specimens were taken before and after water contact; the specimens were immediately frozen, sectioned, and stained histochemically for acetylcholinesterase (AChE) activity. This was localized in the nerve fibers surrounding eccrine sweat glands and was quantified by microspectrophotometry. In AP and polycythemia rubra vera after water exposure a significantly increased AChE activity suggesting acetylcholine release was observed, whereas in the patient with cold urticaria and the controls, a significant decrease was noted. Two related patients with AP had an inherited abnormality of serum cholinesterase, which, however, had no obvious correlation with their particular disease. The proof of AChE activation might support the clinical diagnosis and indicate a hypothetical involvement of eccrine sweat glands in the pathogenesis of AP. PMID:3337547

  18. Inhibition of Acetylcholinesterase Modulates NMDA Receptor Antagonist Mediated Alterations in the Developing Brain

    PubMed Central

    Bendix, Ivo; Serdar, Meray; Herz, Josephine; von Haefen, Clarissa; Nasser, Fatme; Rohrer, Benjamin; Endesfelder, Stefanie; Felderhoff-Mueser, Ursula; Spies, Claudia D.; Sifringer, Marco

    2014-01-01

    Exposure to N-methyl-d-aspartate (NMDA) receptor antagonists has been demonstrated to induce neurodegeneration in newborn rats. However, in clinical practice the use of NMDA receptor antagonists as anesthetics and sedatives cannot always be avoided. The present study investigated the effect of the indirect cholinergic agonist physostigmine on neurotrophin expression and the extracellular matrix during NMDA receptor antagonist induced injury to the immature rat brain. The aim was to investigate matrix metalloproteinase (MMP)-2 activity, as well as expression of tissue inhibitor of metalloproteinase (TIMP)-2 and brain-derived neurotrophic factor (BDNF) after co-administration of the non-competitive NMDA receptor antagonist MK801 (dizocilpine) and the acetylcholinesterase (AChE) inhibitor physostigmine. The AChE inhibitor physostigmine ameliorated the MK801-induced reduction of BDNF mRNA and protein levels, reduced MK801-triggered MMP-2 activity and prevented decreased TIMP-2 mRNA expression. Our results indicate that AChE inhibition may prevent newborn rats from MK801-mediated brain damage by enhancing neurotrophin-associated signaling pathways and by modulating the extracellular matrix. PMID:24595240

  19. Effect of fluorocarbons on acetylcholinesterase activity and some counter measures

    NASA Technical Reports Server (NTRS)

    Young, W.; Parker, J. A.

    1975-01-01

    An isolated vagal sympathetic heart system has been successfully used for the study of the effect of fluorocarbons (FCs) on cardiac performance and in situ enzyme activity. Dichlorodifluoromethane sensitizes this preparation to sympathetic stimulation and to exogenous epinephrine challenge. Partial and complete A-V block and even cardiac arrest have been induced by epinephrine challenge in the FC sensitized heart. Potassium chloride alone restores the rhythmicity but not the normal contractility of the heart in such a situation. Addition of glucose will, however, completely restore the normal function of the heart which is sensitized by dichlorodifluoromethane. The ED 50 values of acetylcholinesterase activity which are used as a measure of relative effectiveness of fluorocarbons are compared with the maximum permissible concentration. Kinetic studies indicate that all the fluorocarbons tested so far are noncompetitive.

  20. Baseline acetylcholinesterase activity and serotonin plasma levels are not associated with delirium in critically ill patients

    PubMed Central

    Tomasi, Cristiane Damiani; Salluh, Jorge; Soares, Márcio; Vuolo, Francieli; Zanatta, Francieli; Constantino, Larissa de Souza; Zugno, Alexandra Ioppi; Ritter, Cristiane; Dal-Pizzol, Felipe

    2015-01-01

    Objective The aim of this study was to investigate whether plasma serotonin levels or acetylcholinesterase activities determined upon intensive care unit admission could predict the occurrence of acute brain dysfunction in intensive care unit patients. Methods A prospective cohort study was conducted with a sample of 77 non-consecutive patients observed between May 2009 and September 2010. Delirium was determined using the Confusion Assessment Method for the Intensive Care Unit tool, and the acetylcholinesterase and serotonin measurements were determined from blood samples collected up to a maximum of 24 h after the admission of the patient to the intensive care unit. Results In the present study, 38 (49.6%) patients developed delirium during their intensive care unit stays. Neither serum acetylcholinesterase activity nor serotonin level was independently associated with delirium. No significant correlations of acetylcholinesterase activity or serotonin level with delirium/coma-free days were observed, but in the patients who developed delirium, there was a strong negative correlation between the acetylcholinesterase level and the number of delirium/coma-free days, indicating that higher acetylcholinesterase levels are associated with fewer days alive without delirium or coma. No associations were found between the biomarkers and mortality. Conclusions Neither serum acetylcholinesterase activity nor serotonin level was associated with delirium or acute brain dysfunction in critically ill patients. Sepsis did not modify these relationships. PMID:26340158

  1. Tabernaemontana divaricata extract inhibits neuronal acetylcholinesterase activity in rats.

    PubMed

    Chattipakorn, Siriporn; Pongpanparadorn, Anucha; Pratchayasakul, Wasana; Pongchaidacha, Anchalee; Ingkaninan, Kornkanok; Chattipakorn, Nipon

    2007-03-01

    The current pharmacotherapy for Alzheimer's disease (AD) is the use of acetylcholinesterase inhibitors (AChE-Is). A previous in vitro study showed that Tabernaemontana divaricata extract (TDE) can inhibit AChE activity. However, neither the AChE inhibitory effects nor the effect on neuronal activity of TDE has been investigated in vivo. To determine those effects of TDE in animal models, the Ellman's colorimetric method was implemented to investigate the cortical and circulating cholinesterase (ChE) activity, and Fos expression was used to determine the neuronal activity in the cerebral cortex, following acute administration of TDE with various doses (250, 500 and 1000 mg/kg) and at different time points. All doses of TDE 2 h after a single administration significantly inhibited cortical AChE activity and enhanced neuronal activity in the cerebral cortex. The enhancement of Fos expression and AChE inhibitory effects in the cerebral cortex among the three TDE-treated groups was not significantly different. A 2 h interval following all doses of TDE administration had no effect on circulating ChE activity. However, TDE significantly inhibited circulating AChE 10, 30 and 60 min after administration. Our findings suggest that TDE is a reversible AChE-I and could be beneficial as a novel therapeutic agent for AD. PMID:17023131

  2. EEG SPECTRA, BEHAVIORAL STATES AND MOTOR ACTIVITY IN RATS EXPOSED TO ACETYLCHOLINESTERASE INHIBITOR CHLORPYRIFOS.

    EPA Science Inventory

    Exposure to organophosphate pesticides (OP) has been associated with sleep disorders: insomnia and ?excessive dreaming'. However neuronal mechanisms of these effects have not been analyzed. OP inhibit acetylcholinesterase activity leading to a hyperativity of the brain cholin...

  3. Acetylcholinesterase Activity and Neurodevelopment in Boys and Girls

    PubMed Central

    Himes, John H.; Jacobs, David R.; Alexander, Bruce H.; Gunnar, Megan R.

    2013-01-01

    BACKGROUND: Organophosphate exposures can affect children’s neurodevelopment, possibly due to neurotoxicity induced by acetylcholinesterase (AChE) inhibition, and may affect boys more than girls. We tested the hypothesis that lower AChE activity is associated with lower neurobehavioral development among children living in Ecuadorian floricultural communities. METHODS: In 2008, we examined 307 children (age: 4–9 years; 52% male) and quantified AChE activity and neurodevelopment in 5 domains: attention/executive functioning, language, memory/learning, visuospatial processing, and sensorimotor (NEPSY-II test). Associations were adjusted for demographic and socioeconomic characteristics and height-for-age, flower worker cohabitation, and hemoglobin concentration. RESULTS: Mean ± standard deviation AChE activity was 3.14 ± 0.49 U/mL (similar for both genders). The range of scores among neurodevelopment subtests was 5.9 to 10.7 U (standard deviation: 2.6–4.9 U). Girls had a greater mean attention/executive functioning domain score than boys. In boys only, there were increased odds ratios of low (<9th percentile) neurodevelopment among those in the lowest tertile versus the highest tertile of AChE activity (odds ratios: total neurodevelopment: 5.14 [95% confidence interval (CI): 0.84 to 31.48]; attention/executive functioning domain: 4.55 [95% CI: 1.19 to 17.38], memory/learning domain: 6.03 [95% CI: 1.17 to 31.05]) after adjustment for socioeconomic and demographic factors, height-for-age, and hemoglobin. Within these domains, attention, inhibition and long-term memory subtests were most affected. CONCLUSIONS: Low AChE activity was associated with deficits in neurodevelopment, particularly in attention, inhibition, and memory in boys but not in girls. These critical cognitive skills affect learning and academic performance. Added precautions regarding secondary occupational pesticide exposure would be prudent. PMID:24249815

  4. Zingipain, a ginger protease with acetylcholinesterase inhibitory activity.

    PubMed

    Rungsaeng, Porlin; Sangvanich, Polkit; Karnchanatat, Aphichart

    2013-06-01

    In order to search for new acetylcholinesterase inhibitors (AChEIs), 15 Zingiberaceae plants were tested for AChEI activity in rhizome extracts. The crude homogenate and ammonium sulfate cut fraction of Zingiber officinale contained a significant AChEI activity. Eighty percent saturation ammonium sulfate precipitation and diethylaminoethyl cellulose ion exchange chromatography (unbound fraction) enriched the protein to a single band on nondenaturing and reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis (approximately 33.5 kDa). Gelatin-degrading zymography showed that the AChEI-containing band also contained cysteine protease activity. The AChEI activity was largely stable between -20 and 60 °C (at least over 120 min) and over a broad pH range (2-12). The AChEI activity was stimulated strongly by Mn(2+) and Cu(2+) at 1-10 mM and weakly by Ca(2+), Fe(2+), Mg(2+), and Zn(2+) at 1 mM, but was inhibited at 10 mM. In contrast, Hg(2+) and ethylenediaminetetraacetic acid were very and moderately strongly inhibitory, respectively. In-gel tryptic digestion with liquid chromatography-tandem mass spectroscopy resolution revealed two heterogeneous peptides, a 16-amino-acid-long fragment with 100 % similarity to zingipain-1, which is a cysteine protease from Z. officinale, and a 9-amino-acid-long fragment that was 100 % identical to actinidin Act 2a, suggesting that the preparation was heterogeneous. AChEI exhibited noncompetitive inhibition of AChE for the hydrolysis of acetylthiocholine iodide with a K(i) value of 9.31 mg/ml. PMID:23625608

  5. Compounds from Gum Ammoniacum with Acetylcholinesterase Inhibitory Activity

    PubMed Central

    Adhami, Hamid-Reza; Lutz, Johannes; Kählig, Hanspeter; Zehl, Martin; Krenn, Liselotte

    2013-01-01

    The use of herbal medicinal preparations in dementia therapy has been studied based on experience from traditional medicine. A dichloromethane extract of gum ammoniacum, the gum-resin from Dorema ammoniacum D. Don had shown acetylcholinesterase (AChE) inhibitory activity in a previous study. The aim of this study was the isolation and characterization of the active compounds from this resin. The extract was investigated by a respective colorimetric microplate assay and the active zones were identified via TLC bioautography and isolated using several chromatographic techniques. The structures of the active components were characterized by one- and two-dimensional 1H and 13C NMR spectroscopy and mass spectrometry as (2′S,5′S)-2′-ethenyl-5′-(3-hy-droxy-6-methyl-4-oxohept-5-en-2-yl)-7-methoxy-2′-methyl-4H-spiro[chromene-3,1′-cyclopentane]-2,4-dione (1), which is an analogue of doremone A and a new natural compound, and as (2′S,5′R)-2′-ethenyl-5′-[(2R,4R)-4-hydroxy-6-methyl-3-oxohept-5-en-2-yl]-7-methoxy-2′-methyl-4H-spiro[chromene-3,1′-cyclo-pentane]-2,4-dione (2 = doremone A), (4E,8E)-1-(2,4-dihydroxyphenyl)-5,9,13-trimethyltetradeca-4,8,12-trien-1-one (3 = dshamirone), and 4,7-dihydroxy-3-[(2E,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-yl]-2H-chromen-2-one (4 = am-moresinol). Dshamirone turned out to be the most active compound with an IC50 value for AChE inhibitory activity of 23.5 μM, whereas the other substances showed weak activity. The concentrations of the analytes in the resin were determined by HPLC as 3.1%, 4.6%, 1.9%, and 9.9%, respectively. PMID:24106674

  6. Acetylcholinesterase activity in regions of mouse brain following acute and chronic treatment with a benzodiazepine inverse agonist.

    PubMed Central

    Appleyard, M. E.; Taylor, S. C.; Little, H. J.

    1990-01-01

    1. Chronic administration of the benzodiazepine inverse agonist FG 7142 has previously been shown to induce seizure activity in mice. In the present study we have investigated the effects of acute and chronic treatment with FG 7142 in mice on the levels of acetylcholinesterase activity in cortex, hippocampus, midbrain and striatum. We have also investigated the effects of acute and chronic stress in the form of handling (vehicle-injection) on acetylcholinesterase levels. 2. A single dose of FG 7142 produced a marked elevation of total acetylcholinesterase activities in the hippocampus and midbrain when compared with vehicle-injected control levels, but the levels were not different from those in unhandled animals. 3. Acute stress, in the form of vehicle-injection produced decreases in cortical and hippocampal soluble acetylcholinesterase activity but FG 7142 had no effect upon these stress-induced changes. 4. Total cortical and hippocampal acetylcholinesterase activities were increased by 56% and 16% respectively in the chronic FG 7142-treated mice that exhibited seizure activity (compared with vehicle-injected controls). 5. Soluble acetylcholinesterase activity in the midbrain was decreased to 82% of control levels only in animals that had undergone FG 7142-induced kindling. Smaller or no changes in acetylcholinesterase activity in the midbrain were observed in chronically FG 7142-treated animals that exhibited no seizure activity. 6. Mice that did not demonstrate seizure activity in response to chronic FG 7142 treatment showed alterations in the soluble acetylcholinesterase activities of the hippocampus and midbrain.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1963800

  7. PHOTOREGULATION OF BIOLOGICAL ACTIVITY BY PHOTOCROMIC REAGENTS, II. INHIBITORS OF ACETYLCHOLINESTERASE*†

    PubMed Central

    Bieth, Joseph; Vratsanos, Spyros M.; Wassermann, Norbert; Erlanger, Bernard F.

    1969-01-01

    The enzymic activity of acetylcholinesterase can be photoregulated through the mediation of photochromic inhibitors of the enzyme. N-p-phenylazophenyl-N-phenylcarbamyl fluoride, an irreversible inhibitor of acetylcholinesterase, exists as two geometric isomers which are interconvertible through the action of light. The cis isomer, which predominates after exposure to light of 320 nm, is more active than the trans isomer, which results from exposure to light of 420 nm. It was possible, therefore, to use light energy to regulate the inactivation of the enzyme. Similarly, levels of acetylcholinesterase activity could be photo-regulated in a completely reversible manner by means of the photochromic reversible inhibitor p-phenylazophenyltrimethylammonium chloride. These experiments can serve as models for similar phenomena observed in nature, particularly in photoperiodic rhythms of higher animals. Images PMID:5264140

  8. Effects of a neonicotinoid insecticide (acetamiprid) on acetylcholinesterase activity and cuticular hydrocarbons profil in German cockroaches.

    PubMed

    Morakchi, S; Maïza, A; Farine, P; Aribi, N; Soltani, N

    2005-01-01

    Acetamiprid was incorporated into the diet at 2% dose corresponding to the LD50 and orally administrated to newly emerged adults of the German cockroach Blattella germanica and investigated on acetylcholinesterase activity and cuticular hydrocarbons profil. Acetylcholinesterase specific activity was determined on adult males and females after 24, 48 and 72 hours of treatment. Pentanic extracts of cuticular hydrocarbons in males and females after 6 days of treatment were analysed by gas chromatography. Data revealed an increase in acetylcholinesterase activity in both sexes from the control series. However, a significant inhibition in AChE was observed after treatment at 24, 48 and 72 hours especially in females. In addition, hydrocarbons profils were found qualitatively similar in all groups of insects. However, slight quantitative differences between sexes in control series were noted. Acetamiprid feminize the cuticular profil in males with significant reduction of cuticular compound, and these allowed separation of insects into two groups using multivariate analysis. PMID:16628926

  9. Chronic dietary exposure to chlorpyrifos causes behavioral impairments, low activity of brain membrane-bound acetylcholinesterase, and increased brain acetylcholinesterase-R mRNA.

    PubMed

    López-Granero, Caridad; Cardona, Diana; Giménez, Estela; Lozano, Rafael; Barril, José; Sánchez-Santed, Fernando; Cañadas, Fernando

    2013-06-01

    Chlorpyrifos (CPF) is an organophosphate (OP) insecticide that is metabolically activated to the highly toxic chlorpyrifos oxon. Dietary exposure is the main route of intoxication for non-occupational exposures. However, only limited behavioral effects of chronic dietary exposure have been investigated. Therefore, male Wistar rats were fed a dose of 5mg/kg/day of CPF for thirty-one weeks. Animals were evaluated in spatial learning and impulsivity tasks after 21 weeks of CPF dietary exposure and one week after exposure ended, respectively. In addition, the degree of inhibition of brain acetylcholinesterase (AChE) was evaluated for both the soluble and particulate forms of the enzyme, as well as AChE gene expression. Also, brain acylpeptide hydrolase (APH) was investigated as an alternative target for OP-mediated effects. All variables were evaluated at various time points in response to CPF diet and after exposure ended. Results from behavioral procedures suggest cognitive and emotional disorders. Moreover, low levels of activity representing membrane-bound oligomeric forms (tetramers) were also observed. In addition, increased brain AChE-R mRNA levels were detected after four weeks of CPF dietary exposure. However, no changes in levels of brain APH were observed among groups. In conclusion, our data point to a relationship between cognitive impairments and changes in AChE forms, specifically to a high inhibition of the particulate form and a modification of alternative splicing of mRNA during CPF dietary exposure. PMID:23545134

  10. Phenolic Lipids Affect the Activity and Conformation of Acetylcholinesterase from Electrophorus electricus (Electric eel)

    PubMed Central

    Stasiuk, Maria; Janiszewska, Alicja; Kozubek, Arkadiusz

    2014-01-01

    Phenolic lipids were isolated from rye grains, cashew nutshell liquid (CNSL) from Anacardium occidentale, and fruit bodies of Merrulius tremellosus, and their effects on the electric eel acetylcholinesterase activity and conformation were studied. The observed effect distinctly depended on the chemical structure of the phenolic lipids that were available for interaction with the enzyme. All of the tested compounds reduced the activity of acetylcholinesterase. The degree of inhibition varied, showing a correlation with changes in the conformation of the enzyme tested by the intrinsic fluorescence of the Trp residues of the protein. PMID:24787269

  11. THE INHIBITION OF ACETYLCHOLINESTERASE ACTIVITY IN PINK SHRIMP 'PENAEUS DUORARUM' BY METHYL PARATHION AND ITS OXON

    EPA Science Inventory

    The inhibition of acetylcholinesterase, E.C.3.1.1.7, (AChE) activity in the ventral nerve cord of pink shrimp (Penaeus duorarum) by methyl parathion (MPT) and methyl paraoxon (MPO) was investigated. When the animals were exposed to these compounds in water (in vivo), AChE activit...

  12. Hyperglycemia induces memory impairment linked to increased acetylcholinesterase activity in zebrafish (Danio rerio).

    PubMed

    Capiotti, Katiucia Marques; De Moraes, Daiani Almeida; Menezes, Fabiano Peres; Kist, Luiza Wilges; Bogo, Maurício Reis; Da Silva, Rosane Souza

    2014-11-01

    Diabetes mellitus, which causes hyperglycemia, affects the central nervous system and can impairs cognitive functions, such as memory. The aim of this study was to investigate the effects of hyperglycemia on memory as well as on the activity of acethylcholinesterase. Hyperglycemia was induced in adult zebrafish by immersion in glucose 111mM by 14 days. The animals were divided in 4 groups: control, glucose-treated, glucose-washout 7-days and glucose-washout 14-days. We evaluated the performance in inhibitory avoidance task and locomotor activity. We also determined acethylcholinesterase activity and gene expression from whole brain. In order to counteract the effect of hyperglycemia underlined by effects on acethylcholinesterase activity, we treated the animals with galantamine (0.05ng/g), an inhibitor of this enzyme. Also we evaluated the gene expression of insulin receptor and glucose transporter from zebrafish brain. The hyperglycemia promoted memory deficit in adult zebrafish, which can be explained by increased AChE activity. The ache mRNA levels from zebrafish brain were decrease in 111mM glucose group and returned to normal levels after 7 days of glucose withdrawal. Insulin receptors (insra-1, insra-2, insrb-1 and insrb-2) and glut-3 mRNA levels were not significantly changed. Our results also demonstrated that galantamine was able to reverse the memory deficit caused by hyperglycemia, demonstrating that these effects involve modulation of AChE activity. These data suggest that the memory impairment induced by hyperglycemia is underlined by the cholinergic dysfunction caused by the mechanisms involving the control of acetylcholinesterase function and gene expression. PMID:25157430

  13. Antioxidant and anti-acetylcholinesterase activities of extracts from Rapistrum rugosum in Tunisia

    PubMed Central

    Amel, Omri Hichri; Malek, Besbes Hlila; Hichem, Ben Jannet; Ali, Lamari; Mahjoub, Aouni; Boulbaba, Selmi

    2013-01-01

    Objective To investigate the antioxidant potential and anti-acetylcholinesterase activity of Rapistrum rugosum extracts. Methods The crude, ethyl acetate, butanol and water extracts prepared from flowers, roots, stems and leaves of Rapistrum rugosum were tested at 1 mg/mL to determine their total polyphenol content, total flavonoid content and total condensed tannin content. Their antioxidant activity was assessed at different concentrations (0.0312, 0.0625, 0.1250, 0.25, 0.50 and 1.00 mg/mL) by using DPPH, ABTS, reducing power and β-carotene bleAChIng inhibition activity. Anti-acetylcholinesterase activity was also determined. Results The extract of leaves and stems had the highest total phenolic content [(110.45±0.03) mg gallic acid equivalent/g dry weight]. The ethyl acetate extract of flowers had the highest total flavonoid content [(24.62±0.13) mg quercetin equivalent/g dry weight]. The butanolic fraction of flowers had the highest total condensed tannin content [(317.85±0.01) mg catechin equivalent/g dry weight]. The crude extracts of flowers exhibited an interesting antioxidant activity for DPPH assay (93.00±0.01)% at 1 mg/mL. The greatest acetylcholinesterase inhibitory activity (IC50=1.60 mg/mL) was exhibited by the crude extracts from the flowers. Conclusions The results demonstrated that Rapistrum rugosum contains active constituents which possess antioxidant and anti-acetylcholinesterase activities.

  14. Antioxidant and anti-acetylcholinesterase activities of extracts and secondary metabolites from Acacia cyanophylla

    PubMed Central

    Ghribia, Lotfi; Ghouilaa, Hatem; Omrib, Amel; Besbesb, Malek; Janneta, Hichem Ben

    2014-01-01

    Objective To investigate the antioxidant potential and anti-acetycholinesterase activity of compounds and extracts from Acacia cyanophylla (A. cyanophylla). Methods Three polyphenolic compounds were isolated from ethyl acetate extract of A. cyanophylla flowers. They have been identified as isosalipurposide 1, quercetin 2 and naringenin 3. Their structures were elucidated by extensive spectroscopic methods including 1D and 2D NMR experiments as well as ES-MS. The prepared extracts and the isolated compounds 1-3 were tested for their antioxidant activity using 1′-1′-diphenylpicrylhydrazyl (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) scavenging assays and reducing power. They have been also investigated for inhibitory effect against acetylcholinesterase using the microplate assay. Results In the DPPH test, the EtOAc extract of flowers exhibited the highest antioxidant effect (67.26 µg/mL). Isosalipurposide 1 showed a significant antiradical power against DPPH (81.9 µg/mL). All extracts showed a dose-dependent acetylcholinesterase inhibition. In terms of the IC50 value, the butanolic extract (16.03 µg/mL) was the most potent sample. Isosalipurposide 1 was found to be active against AChE with an IC50 value of 52.04 µg/mL. Conclusions The results demonstrated the important antioxidant and anti-acetylcholinesterase activity of pure compounds and extracts from A. cyanophylla. PMID:25183120

  15. Acetylcholinesterase-Inhibiting Activity of Pyrrole Derivatives from a Novel Marine Gliding Bacterium, Rapidithrix thailandica

    PubMed Central

    Sangnoi, Yutthapong; Sakulkeo, Oraphan; Yuenyongsawad, Supreeya; Kanjana-opas, Akkharawit; Ingkaninan, Kornkanok; Plubrukarn, Anuchit; Suwanborirux, Khanit

    2008-01-01

    Acetylcholinesterase-inhibiting activity of marinoquinoline A (1), a new pyrroloquinoline from a novel species of a marine gliding bacterium Rapidithrix thailandica, was assessed (IC50 4.9 μM). Two related pyrrole derivatives, 3-(2′-aminophenyl)-pyrrole (3) and 2,2-dimethyl-pyrrolo-1,2-dihydroquinoline (4), were also isolated from two other strains of R. thailandica. The isolation of 3 from a natural source is reported here for the first time. Compound 4 was proposed to be an isolation artifact derived from 3. The two isolated compounds were virtually inactive in the acetylcholinesterase-inhibitory assay (enzyme inhibition < 30% at 0.1 g L−1). PMID:19172195

  16. Effect of Moringa oleifera flower extract on larval trypsin and acetylcholinesterase activities in Aedes aegypti.

    PubMed

    Pontual, Emmanuel Viana; Napoleão, Thiago Henrique; Dias de Assis, Caio Rodrigo; de Souza Bezerra, Ranilson; Xavier, Haroudo Satiro; Navarro, Daniela Maria do Amaral Ferraz; Coelho, Luana Cassandra Breitenbach Barroso; Paiva, Patrícia Maria Guedes

    2012-03-01

    Aedes aegypti control is crucial to reducing dengue fever. Aedes aegypti larvae have developed resistance to organophosporous insecticides and the use of natural larvicides may help manage larval resistance by increasing elements in insecticide rotation programs. Here, we report on larvicidal activity of Moringa oleifera flower extract against A. aegypti L(1), L(2), L(3), and L(4) as well as the effect of flower extract on gut trypsin and whole-larval acetylcholinesterase from L(4.) In addition, the heated flower extract was investigated for larvicidal activity against L(4) and effect on larval gut trypsin. Moringa oleifera flower extract contains a proteinaceous trypsin inhibitor (M. oleifera flower trypsin inhibitor, MoFTI), triterpene (β-amyrin), sterol (β-sitosterol) as well as flavonoids (kaempferol and quercetin). Larvicidal activity was detected against L(2), L(3), and L(4) (LC(50) of 1.72%, 1.67%, and 0.92%, respectively). Flower extract inhibited L(4) gut trypsin (MoFTI K(i) = 0.6 nM) and did not affect acetylcholinesterase activity. In vivo assay showed that gut trypsin activity from L(4) treated with M. oleifera flower extract decreased over time (0-1,440 min) and was strongly inhibited (98.6%) after 310 min incubation; acetylcholinesterase activity was not affected. Thermal treatment resulted in a loss of trypsin inhibitor and larvicidal activities, supporting the hypothesis that flower extract contains a proteinaceous trypsin inhibitor that may be responsible for the deleterious effects on larval mortality. PMID:22392801

  17. Regulatory effects of polyamines on membrane-bound acetylcholinesterase

    PubMed Central

    Kossorotow, A.; Wolf, H. U.; Seiler, N.

    1974-01-01

    The effects of putrescene, spermidine and spermine on membrane-bound acetylcholinesterase from human erythrocyte `ghosts' and the solubilized enzyme of the electric organ of the electric eel were studied by kinetic methods. Measurements were made by using a photometric method which made it possible to record the enzyme reaction in the steady-state phase. Substrate-concentration-dependent activation and inhibition of acetylcholinesterase by polyamines is similar to that by Na+, K+, Ca2+, Mg2+ and certain quaternary and bisquaternary amines. The kinetics suggest an allosteric reaction mechanism. On the basis of the kinetic results a role for the polyamines as modulators of synaptic acetylcholinesterase is proposed. PMID:4462573

  18. Antioedematogenic activity, acetylcholinesterase inhibition and antimicrobial properties of Jacaranda oxyphylla.

    PubMed

    Pereira, V V; Silva, R R; Dos Santos, M H; Dias, D F; Moreira, M E C; Takahashi, J A

    2016-09-01

    Jacaranda oxyphylla Cham. (Bignoniaceae) is a shrub found in the Brazilian cerrado and used in folk medicine to treat microbial infections. The aim of this study was to carry out a phytochemical screening and evaluate antioedematogenic, antimicrobial and antiacetylcholinesterase properties of J. oxyphylla crude extracts. All extracts analysed showed presence of terpenoids, which are potentially active chemical substances. A high AChE inhibitory activity for hexane extract from leaves and for the extracts from twigs was found. Ethanol extract from leaves of J. oxyphylla showed activity against Gram-positive (Staphylococcus aureus and Bacillus cereus) and Gram-negative (Escherichia coli) bacteria. This extract was also effective in inhibiting the stages of inflammation evaluated. Biological investigation and phytochemical screening of J. oxyphylla extracts provided additional evidence of its traditional medicinal value. PMID:26469996

  19. Rubus coreanus Miquel Inhibits Acetylcholinesterase Activity and Prevents Cognitive Impairment in a Mouse Model of Dementia

    PubMed Central

    Kim, Cho Rong; Choi, Soo Jung; Oh, Seung Sang; Kwon, Yoon Kyung; Lee, Na Young; Park, Gwi Gun; Kim, Youn-Jung; Heo, Ho Jin; Jun, Woo Jin; Park, Cheung-Seog; Shin, Dong-Hoon

    2013-01-01

    Abstract To find acetylcholinesterase (AChE) inhibitors for the prevention of neurological disorders, such as Alzheimer's disease, ethanol extracts of promising traditional edible Korean plants were tested. Among them, Rubus coreanus Miquel extract exhibited the most significant AChE inhibitory activity. The effect of R. coreanus extract on trimethyltin-induced memory impairment in mice was investigated using Y-maze and passive avoidance tests. Our results showed that administration of R. coreanus extract significantly improved alternation behavior and step-through latency. In addition, R. coreanus extract was sequentially fractionated, and the purified constituent was determined to be 3,4,5-trihydroxybenzoic acid. PMID:24044488

  20. In vivo and in vitro effects of fructose on rat brain acetylcholinesterase activity: an ontogenetic study.

    PubMed

    Guimarães, Carine A; Biella, Mairis S; Lopes, Abigail; Deroza, Pedro F; Oliveira, Mariana B; Macan, Tamires P; Streck, Emilio L; Ferreira, Gustavo C; Zugno, Alexandra I; Schuck, Patrícia F

    2014-12-01

    Increased fructose concentrations are the biochemical hallmark of fructosemia, a group of inherited disorders on the metabolic pathway of this sugar. The main clinical findings observed in patients affected by fructosemia include neurological abnormalities with developmental delay, whose pathophysiology is still undefined. In the present work we investigated the in vitro and in vivo effects of fructose on acetylcholinesterase (AchE) activity in brain structures of developing rats. For the in vitro experiments, fructose was added at increasing concentrations to the incubation medium. It was observed that fructose provoked an inhibition of acetylcholinesterase activity in cerebral cortex of 30-day-old-rats, even at low concentrations (0.1 mM). For the in vivo experiments, rats were killed 1 h after a single fructose administration (5 µmol/g). Control group received the same volume of saline solution. We found that AchE activity was increased in cerebral cortex of 30- and 60-day-old rats receiving fructose administration. Finally, we observed that AchE activity was unaffected by acute fructose administration in cerebral cortex, striatum or hippocampus of 15- and 90-day-old rats. The present data suggest that a disruption in cholinergic homeostasis may be involved in the pathophysiology of brain damage observed in young patients affected by fructosemia. PMID:25590728

  1. The inhibition activity of selected beta-carboline alkaloids on enzymes of acetylcholinesterase and butyrylcholinesterase.

    PubMed

    Krsková, Zuzana; Martin, Jan; Dusek, Jaroslav

    2011-06-01

    This thesis deals with testing of inhibition activity beta-carboline alkaloids on activity of enzymes acetylcholinesterase (ACHE) and butyrylcholinesterase (BUCHE) using test "Fast Blue B salt" at TLC desk and Ellman's test using spectrophotometer. It was also investigated how dimethylsulfoxide used as a solvent in combination with water affects activity of enzymes and alkaloids. Results show harmine in form of base and salt in water and in mixture of DMSO and water has the hightest inhibition activity on ACHE using eserine as reference substance. Harmalol in form of salt in water and harmine in form of base and salt in mixture of DMSO and water has the hightest activity on BUCHE. It was find out that DMSO considerably affects activity of enzymes and alkaloids. PMID:21838142

  2. Monoclonal antibody AE-2 modulates carbamate and organophosphate inhibition of fetal bovine serum acetylcholinesterase. (Reannouncement with new availability information)

    SciTech Connect

    Wolfe, A.D.; Chiang, P.K.; Doctor, B.P.; Fryar, N.; Rhee, J.P.

    1993-12-31

    The monoclonal antibody AE-2 raised against the human erythrocyte acetylcholinesterase (AChE) dimer (acetylcholine acetylhydrolase, EC 3.1.1.7), binds to other mammalian AChEs, including the tetramer that occurs in fetal bovine serum (FBS). AE2 partially inhibited the rate of hydrolysis of the charged substrate acetylthiocholine by FBS AChE, whereas it increased the rate of hydrolysis of the neutral substrate indophenyl acetate. Present results show that AE-2 decreases the rate of inhibition of FBS AChE by the positively charged organophosphate amition-p-toluene sulfonate and the positively charged carbamates pyridostigmine and neostigmine but accelerate inhibition of FBS AChE by neutral organophosphates paraoxon and diisopropylfluorophosphate. Results suggest that AE-2 may allosterically modulate an anionic site in the catalytic center of FBS AChE.

  3. Screening for acetylcholinesterase inhibitory activity in plants used in Thai traditional rejuvenating and neurotonic remedies.

    PubMed

    Ingkaninan, Kornkanok; Temkitthawon, Prapapan; Chuenchom, Kanchanaporn; Yuyaem, Thitaree; Thongnoi, Warawit

    2003-12-01

    Acetylcholinesterase (AChE) inhibitor has been used as a drug for the symptomatic treatment of Alzheimer's disease. In order to search for new AChE inhibitors, 32 plants used in Thai traditional rejuvenating and neurotonic remedies were collected. The plant methanolic extracts were tested for AChE inhibitory activity using Ellman's colorimetric method in 96-welled microplates. The results showed that the methanolic extracts from roots of Stephania suberosa Forman. and Tabernaemontana divaricata (L.) R.Br. ex Roem. & Schult. at concentration of 0.1 mg/ml inhibited more than 90% of AChE activity. At the same concentration, four extracts, i.e. stems of Piper interruptum Opiz., seeds of Piper nigrum L., rootbarks of Butea superba Roxb. and roots of Cassia fistula L. extracts showed 50-65% inhibitory activity on AChE. The rest of the extracts showed the AChE inhibitory activity below 50%. PMID:14611889

  4. Phytochemicals Content, Antioxidant Activity and Acetylcholinesterase Inhibition Properties of Indigenous Garcinia parvifolia Fruit

    PubMed Central

    Ali Hassan, Siti Hawa; Fry, Jeffrey R.

    2013-01-01

    Garcinia parvifolia belongs to the same family as mangosteen (Garcinia mangostana), which is known locally in Sabah as “asam kandis” or cherry mangosteen. The present study was conducted to determine the phytochemicals content (total phenolic, flavonoid, anthocyanin, and carotenoid content) and antioxidant and acetylcholinesterase inhibition activity of the flesh and peel of G. parvifolia. All samples were freeze-dried and extracted using 80% methanol and distilled water. For the 80% methanol extract, the flesh of G. parvifolia displayed higher phenolic and flavonoid contents than the peel, with values of 7.2 ± 0.3 mg gallic acid equivalent (GAE)/g and 5.9 ± 0.1 mg rutin equivalent (RU)/g, respectively. Anthocyanins were detected in the peel part of G. parvifolia but absent in the flesh. The peel of G. parvifolia displayed higher total carotenoid content as compared to the flesh part with the values of 17.0 ± 0.3 and 3.0 ± 0.0 mg β-carotene equivalents (BC)/100 g, respectively. The free-radical scavenging, ferric reducing, and acetylcholinesterase inhibition effect of the flesh were higher as compared to the peel in both extracts. These findings suggested that the edible part of G. parvifolia fruit has a potential as a natural source of antioxidant and anti-Alzheimer's agents. PMID:24288662

  5. Lycodine-type alkaloids from Lycopodiastrum casuarinoides and their acetylcholinesterase inhibitory activity.

    PubMed

    Zhang, Dong-Bo; Chen, Jian-Jun; Song, Qiu-Yan; Zhang, Li; Gao, Kun

    2014-01-01

    Four new lycodine-type alkaloids, namely 16-hydroxyhuperzine B (1), N-methyl-11-acetoxyhuperzine B (2), 8,15-dihydrolycoparin A (3) and (7S,12S,13R)-huperzine D-16-O-β-d-glucopyranoside (4), along with ten known analogues 5-14, were isolated from the whole plant of Lycopodiastrum casuarinoides. The structures of the new compounds were elucidated by means of spectroscopic techniques (IR, MS, NMR, and CD) and chemical methods. Compounds 1 and 2 possessed four connected six-membered rings, while compounds 3 and 4 were piperidine ring cleavage products. In particular, compound 4 was a lycopodium alkaloidal glycoside which is reported for the first time. Among the isolated compounds N-demethylhuperzinine (7), huperzine C (8), huperzine B (9) and lycoparin C (13) possessed significant inhibitory activity against acetylcholinesterase, and the new compound 1 showed moderate inhibitory activity. The structure activity relationships were discussed. PMID:25014530

  6. Effects of methamidophos on acetylcholinesterase activity, behavior, and feeding rate of the white shrimp (Litopenaeus vannamei).

    PubMed

    García-de la Parra, L M; Bautista-Covarrubias, J C; Rivera-de la Rosa, N; Betancourt-Lozano, M; Guilhermino, L

    2006-11-01

    The toxicity of methamidophos on the shrimp Litopenaeus vannamei was evaluated using acetylcholinesterase (AChE) activity, behavior, and feeding rate as effect criteria. The biochemical characterization of the soluble cholunesterase (ChE) present in both muscle and eye tissues of L. vannamei was performed in a first phase of the study. In both tissues, almost full inhibition of enzyme activity by eserine sulfate was found, indicating that the measured activity is mainly from ChE and not from other esterases. The highest rate of substrate hydrolysis was found when acetylthiocholine was used as substrate. To evaluate the effects of methamidophos on L. vannamei AChE, behavior, and feeding rate, shrimps were exposed for 24h to several sublethal concentrations of methamidophos. Significant effects of the pesticide on behavior and AChE were found, with behavior being a more sensitive endpoint than AChE inhibition. Feeding rate was not a sensible endpoint under conditions tested. PMID:16249032

  7. Inhibition effect of graphene oxide on the catalytic activity of acetylcholinesterase enzyme.

    PubMed

    Wang, Yong; Gu, Yao; Ni, Yongnian; Kokot, Serge

    2015-11-01

    Variations in the enzyme activity of acetylcholinesterase (AChE) in the presence of the nano-material, graphene oxide (GO), were investigated with the use of molecular spectroscopy UV-visible and fluorescence methods. From these studies, important kinetic parameters of the enzyme were extracted; these were the maximum reaction rate, Vm , and the Michaelis constant, Km . A comparison of these parameters indicated that GO inhibited the catalytic activity of the AChE because of the presence of the AChE-GO complex. The formation of this complex was confirmed with the use of fluorescence data, which was resolved with the use of the MCR-ALS chemometrics method. Furthermore, it was found that the resonance light-scattering (RLS) intensity of AChE changed in the presence of GO. On this basis, it was demonstrated that the relationship between AChE and GO was linear and such models were used for quantitative analyses of GO. PMID:25620714

  8. Oximes: Inhibitors of Human Recombinant Acetylcholinesterase. A Structure-Activity Relationship (SAR) Study

    PubMed Central

    Sepsova, Vendula; Karasova, Jana Zdarova; Korabecny, Jan; Dolezal, Rafael; Zemek, Filip; Bennion, Brian J.; Kuca, Kamil

    2013-01-01

    Acetylcholinesterase (AChE) reactivators were developed for the treatment of organophosphate intoxication. Standard care involves the use of anticonvulsants (e.g., diazepam), parasympatolytics (e.g., atropine) and oximes that restore AChE activity. However, oximes also bind to the active site of AChE, simultaneously acting as reversible inhibitors. The goal of the present study is to determine how oxime structure influences the inhibition of human recombinant AChE (hrAChE). Therefore, 24 structurally different oximes were tested and the results compared to the previous eel AChE (EeAChE) experiments. Structural factors that were tested included the number of pyridinium rings, the length and structural features of the linker, and the number and position of the oxime group on the pyridinium ring. PMID:23959117

  9. Effects of Green Tea Extract on Learning, Memory, Behavior and Acetylcholinesterase Activity in Young and Old Male Rats

    ERIC Educational Resources Information Center

    Kaur, Tranum; Pathak, C. M.; Pandhi, P.; Khanduja, K. L.

    2008-01-01

    Objective: To study the effects of green tea extract administration on age-related cognition in young and old male Wistar rats. Methods: Young and old rats were orally administered 0.5% green tea extract for a period of eight weeks and were evaluated by passive avoidance, elevated maze plus paradigm and changes in acetylcholinesterase activity.…

  10. Comparison of the oxime-induced reactivation of erythrocyte and muscle acetylcholinesterase following inhibition by sarin or paraoxon, using a perfusion model for the real-time determination of membrane-bound acetylcholinesterase activity.

    PubMed

    Eckert, Saskia; Eyer, Peter; Herkert, Nadja; Bumm, Rudolf; Weber, Georg; Thiermann, Horst; Worek, Franz

    2008-02-01

    The purpose of these experiments was to compare oxime-induced reactivation rate constants of acetylcholinesterase from different human tissue sources inhibited by organophosphorus compounds. To this end, preliminary testing was necessary to generate a stable system both for working with erythrocytes and musculature. We established a dynamically working in vitro model with a fixed enzyme source in a bioreactor that was perfused with acetylthiocholine, Ellman's reagent and any agent of interest (e.g. nerve agents, oximes) and analyzed in a common HPLC flow-through detector. The enzyme reactor was composed of a particle filter (Millex-GS, 0.22 microm) containing a thin layer of membrane-bound acetylcholinesterase and was kept at constant temperature in a water bath. At constant flow the height of absorbance was directly proportional to the enzyme activity. To start with, we applied this system to human red cell membranes and then adapted the system to acetylcholinesterase of muscle tissue. Homogenate (Ultra-Turrax and Potter-Elvehjem homogenizer) of human muscle tissue (intercostal musculature) was applied to the same particle filter and perfused in a slightly modified way, as done with human red cell membranes. We detected no decrease of acetylcholinesterase activity within 2.5h and we reproducibly determined reactivation rate constants for reactivation with obidoxime (10 microM) or HI 6 (30 microM) of sarin-inhibited human muscle acetylcholinesterase (0.142+/-0.004 min(-1) and 0.166+/-0.008 min(-1), respectively). The reactivation rate constants of erythrocyte and muscular acetylcholinesterase differed only slightly, highlighting erythrocyte acetylcholinesterase as a proper surrogate marker. PMID:17977518

  11. Screening the methanol extracts of some Iranian plants for acetylcholinesterase inhibitory activity

    PubMed Central

    Gholamhoseinian, A.; Moradi, M.N.; Sharifi-far, F.

    2009-01-01

    Acetylcholinesterase (AChE) is the main enzyme for the breakdown of acetylcholine. Nowadays, usage of the inhibitors of this enzyme is one of the most important types of treatment of mild to moderate neurodegenerative diseases such as Alzheimer’s disease. Herbal medicines can be a new source of inhibitors of this enzyme. In this study we examined around 100 different plants to evaluate their inhibitory properties for AChE enzyme. Plants were scientifically identified and their extracts were prepared by methanol percolation. Acetylcholinesterase activity was measured using a colorimetric method in the presence or absence of the extracts. Eserine was used as a positive control. Methanol extracts of the Levisticum officinale, Bergeris integrima and Rheum ribes showed more than 50% AChE inhibitory activity. The inhibition kinetics were studied in the presence of the most effective extracts. L. officinale and B. integrima inhibited AChE activity in a non-competitive manner, while R. ribes competitively inhibitied the enzyme as revealed by double-reciprocal Linweaver-Burk plot analysis. Under controlled condition, Km and Vmax values of the enzyme were found to be 9.4 mM and 0.238 mM/min, respectively. However, in the presence of L. officinale, B. integrima, and R. ribes extracts, Vmax values were 0.192, 0.074 and 0.238 mM/min, respectively. Due to the competitive inhibition of the enzyme by R. ribes extract, the Km value of 21.2 mM was obtained. The concentration required for 50% enzyme inhibition (IC50 value) was 0.5, 0.9, and 0.95 mg/ml for the L. officinale, B. integrima and R. ribes extracts, respectively. The IC50 of the eserine was determined to be 0.8 mg/ml. PMID:21589805

  12. Development of quantitative structure activity relationships for the binding affinity of methoxypyridinium cations for human acetylcholinesterase.

    PubMed

    Morrill, Jason A; Topczewski, Joseph J; Lodge, Alexander M; Yasapala, Nilanthi; Quinn, Daniel M

    2015-11-01

    Among the most toxic substances known are the organophosphorus (OP) compounds used as pesticides and chemical warfare agents. Owing to their high toxicity there is a number of efforts underway to develop effective therapies for OP agent exposure. To date all therapies in use treat inhibited acetylcholinesterase (AChE), but are ineffective for the treatment of inhibited AChE, which has undergone a subsequent hydrolysis process, referred to as aging. Toward developing a therapy for treating victims of OP intoxication in the aged state we have developed Quantitative Structure-Activity Relationships (QSARs) based on the AM1 semiempirical quantum mechanical method using the program, CODESSA (COmprehensive Descriptors for Structural and Statistical Analysis). Using this methodology we obtained a multiple correlation QSAR equation which gave R(2)=0.9359 for a random training set of 38 ligands and R(2)=0.9236 for prediction on a random test set of 9 ligands. PMID:26454505

  13. Salivary Acetylcholinesterase Activity Is Increased in Parkinson's Disease: A Potential Marker of Parasympathetic Dysfunction

    PubMed Central

    Fedorova, Tatyana; Knudsen, Cindy Soendersoe; Mouridsen, Kim; Nexo, Ebba; Borghammer, Per

    2015-01-01

    Introduction. Decreased salivary flow and xerostomia are frequent findings in Parkinson's disease (PD), possibly caused by alterations in the parasympathetic tonus. Here we explore salivary acetylcholinesterase (AChE) activity as a potential biomarker in PD. Methods. We measured salivary flow, AChE activity, and total protein concentration in 30 PD patients and 49 healthy controls. We also performed exploratory correlation analyses with disease duration, motor symptom severity, autonomic complaints, and other nonmotor symptoms. Results. PD patients displayed significantly decreased salivary flow rate, significantly increased salivary AChE activity, and total protein concentration. Importantly, the AChE activity/total protein ratio was significantly increased in PD patients, suggesting that increased AChE activity cannot be explained solely by upconcentration of saliva. The Unified PD Rating Scale (UPDRS) score displayed significant correlation with total salivary protein (P = 0.002) and near-significant correlation with salivary flow (P = 0.07). Color vision test scores were also significantly correlated with AChE activity (P = 0.04) and total protein levels (P = 0.002). Conclusion. Salivary AChE activity is increased in PD patients compared to healthy controls. Future studies are needed to elucidate whether this parameter reflects the extent of neuronal damage and parasympathetic denervation in the salivary glands of PD patients. PMID:25767737

  14. Acetylcholinesterase activity in CSF in schizophrenia, depression, Alzheimer's disease and normals.

    PubMed

    Deutsch, S I; Mohs, R C; Levy, M I; Rothpearl, A B; Stockton, D; Horvath, T; Coco, A; Davis, K L

    1983-12-01

    Acetylcholinesterase (AChE) activity and protein were measured in the CSF of patients with Alzheimer's disease, depression, schizophrenia with and without tardive dyskinesia, and control subjects. AChE activity was assayed by a radioenzymatic method involving the direct extraction of hydrolyzed 3H-acetate into a toluene-based scintillation fluid followed by liquid scintillation spectrometry. AChE activity was proportional to the amount of CSF protein. Greater than 90% of AChE activity in CSF could be inhibited by 10(-3) M eserine. In addition, activity remained stable despite repeated freeze-thawing in an acetone-dry ice bath. Age was found to be positively correlated with CSF protein and AChE activity expressed per volume CSF, but not with AChE measured per milligram protein. No differences between diagnostic groups were found on either measure of AChE when the extraneous factors of age and CSF protein concentrations were controlled, nor were any differences found between groups for CSF protein when age was controlled. PMID:6661467

  15. EEG spectra, behavioral states and motor activity in rats exposed to acetylcholinesterase inhibitor chlorpyrifos.

    PubMed

    Timofeeva, Olga A; Gordon, Christopher J

    2002-06-01

    Exposure to organophosphates (OP) has been associated with sleep disorders such as insomnia and "excessive dreaming." The central mechanisms of these effects are not well understood. OPs inhibit acetylcholinesterase (AChE) activity, leading to a hyperactivity of the brain cholinergic systems that are involved in sleep regulation. We studied alterations in the EEG, behavioral states, motor activity and core temperature in rats orally administered with 10 or 40 mg/kg of the OP insecticide chlorpyrifos (CHP). Occipital EEG, motor activity and core temperature were recorded with telemetric transmitters. Behavioral sleep-wake states were visually scored. Both doses of CHP produced alterations of the EEG (decrease in power of sigma/beta and increase in slow theta and fast gamma bands) characteristic of arousal. EEG alterations were consistent with behavioral changes such as an increase in wakefulness and a decrease in sleep. Waking immobility was a prevalent behavior. We did not detect any overt signs of CHP toxicity, such as an abnormal posture or gait, suggesting that reduced locomotion can be a result of central effects of CHP (such as activation of cholinergic motor inhibitory system) rather than peripheral (such as an impairment of neuromuscular function). Changes in the EEG and behavior occurred independently of the decrease in core temperature. Increased wakefulness together with reduced motor activity after exposure to CHP seems to be a result of hyperactivity in brain cholinergic neuronal networks. PMID:12175464

  16. Nature of stress: differential effects on brain acetylcholinesterase activity and memory in rats.

    PubMed

    Das, Amitava; Rai, Deepak; Dikshit, Madhu; Palit, Gautam; Nath, Chandishwar

    2005-09-16

    Effect of acute, chronic-predictable and chronic-unpredictable stress on memory and acetylcholinesterase (AChE) was investigated in rats. The animals were subjected to 3 type of stressors--(1) acute immobilization stress, (2) chronic-predictable stress i.e., immobilization daily for 5 consecutive days and (3) chronic-unpredictable stress that included reversal of light/dark cycle, over-night fasting, forced-swimming, immobilization and forced exercise in random unpredictable manner daily for 5 consecutive days. Learning and memory function was studied by single trial Passive avoidance test. AChE activity was assayed spectrophotometrically in the detergent (DS) and salt (SS) soluble fractions in different brain regions. Learning was obtained in acute and chronic-predictable stress groups but not in chronic-unpredictable group. Acute, chronic-predictable and chronic-unpredictable stress caused significant decrease in AChE activity in the DS fraction of cortex, hippocampus and hypothalamus as compared to control. Results indicate that AChE in DS fraction is predominantly affected in stressed and stressed-trained group but cognition is affected only by chronic-unpredictable stress. In acute and chronic-predictable groups the decreased AChE activity in the hippocampal DS fraction during learning may be responsible to maintain cognitive function by enhancing the cholinergic activity. PMID:16098992

  17. Acetylcholinesterase activity of synaptic plasma membranes during ageing: effect of L-acetylcarnitine.

    PubMed

    Gorini, A; Ghigini, B; Villa, R F

    1996-01-01

    A physiopathological role for acetylcholine (ACh) was hypothesized during ageing and related neurodegenerative diseases, e.g. dementia. This research was aimed to study acetylcholinesterase (AChE) activity during development and ageing of the frontal cerebral cortex of 4-, 8-, 12-, 16-, 20- and 24-month-old rats. This study was performed on synaptic plasma membranes, the specific subcellular compartment where the enzyme is located in vivo both in control animals and after in vivo acute treatment with L-acetylcarnitine. Maximum AChE activity was unaffected by age, and L-acetylcarnitine treatment increased enzyme activity in synaptic plasma membranes of 8-month-old rats. A comprehensive analysis of these results suggests: (a) the observed alterations in protein can substantially affect neurochemical data if results are presented as specific activities per unit protein; (b) energy metabolism plays the major role in the disturbed ACh metabolism during ageing and (c) the understanding of the mode of action of L-acetylcarnitine in treatment of dementia. PMID:8740629

  18. Inhibitory effect of ebselen on cerebral acetylcholinesterase activity in vitro: kinetics and reversibility of inhibition.

    PubMed

    Martini, Franciele; Bruning, César Augusto; Soares, Suelen Mendonca; Nogueira, Cristina Wayne; Zeni, Gilson

    2015-01-01

    Ebselen is a synthetic organoselenium compound that has been considered a potential pharmacological agent with low toxicity, showing antioxidant, anti-inflammatory and neuroprotective effects. It is bioavailable, blood-brain barrier permeant and safe based on cellular toxicity and Phase I-III clinical trials. There is evidence that ebselen inhibits acetylcholinesterase (AChE) activity, an enzyme that plays a key role in the cholinergic system by hydrolyzing acetylcholine (ACh), in vitro and ex vivo. This system has a well-known relationship with cognitive process, and AChE inhibitors, such as donepezil and galantamine, have been used to treat cognitive deficits, mainly in the Alzheimer's Disease (AD). However, these drugs have poor bioavailability and a number of side effects, including gastrointestinal upsets and hepatotoxicity. In this way, this study aimed to evaluate the effect of ebselen on cerebral AChE activity in vitro and to determine the kinetic profile and the reversibility of inhibition by dialysis. Ebselen inhibited the cerebral AChE activity with an IC50 of 29 µM, similar to IC50 found with pure AChE from electric eel, demonstrating a mixed and reversible inhibition of AChE, since it increased Km and decreased Vmax. The AChE activity was recovered within 60 min of dialysis. Therefore, the use of ebselen as a therapeutic agent for treatment of AD should be considered, although memory behavior tasks are needed to support such hypothesis. PMID:25312723

  19. Highly sensitive assay for acetylcholinesterase activity and inhibition based on a specifically reactive photonic nanostructure.

    PubMed

    Tian, Tian; Li, Xuesong; Cui, Jiecheng; Li, Jian; Lan, Yue; Wang, Chen; Zhang, Meng; Wang, Hui; Li, Guangtao

    2014-09-10

    Assays for acetylcholinesterase (AChE) with high sensitivity and high selectivity as well as facile manipulation have been urgently required in various fields. In this work, a reaction-based photonic strategy was developed for the efficient assay of AChE activity and inhibition based on the synergetic combination of the specific thiol-maleimide addition reaction with photonic porous structure. It was found that various applications including detection of AChE activity, measurement of the related enzymatic kinetics, and screening of inhibitors could be efficiently implemented using such strategy. Remarkably, the unique photonic nanostructure endows the constructed sensing platform with high sensitivity with a limit of detection (LOD) of 5 mU/mL for AChE activity, high selectivity, and self-reporting signaling. Moreover, the label-free solid film-based sensing approach described here has advantages of facile manipulation and bare-eye readout, compared with conventional liquid-phase methods, exhibiting promising potential in practical application for the AChE assay. PMID:25130420

  20. Alkaloids from Peumus boldus and their acetylcholinesterase, butyrylcholinesterase and prolyl oligopeptidase inhibition activity.

    PubMed

    Hošt'álková, Anna; Opletal, Lubomír; Kuneš, Jiří; Novák, Zdeněk; Hrabinová, Martina; Chlebek, Jakub; Čegan, Lukáš; Cahlíková, Lucie

    2015-04-01

    Eleven isoquinoline alkaloids (1-11) were isolated from dried leaves of Peumus boldus Mol. by standard chromatographic methods. The chemical structures were elucidated by MS, and 1D and 2D NMR spectroscopic analysis, and by comparison with literature data. Compounds isolated in sufficient amount were evaluated for their acetylcholinesterase, and butyrylcholinesterase inhibition activity using Ellman's method. In the prolyl oligopeptidase assay, Z-Gly-Pro-p-nitroanilide was used as substrate. Promising butyrylcholinesterase inhibition activities were demonstrated by two benzylisoquinoline alkaloids, reticuline (8) and N-methylcoclaurine (9), with IC50 values of 33.6 ± 3.0 µM and 15.0 ± 1.4 µM, respectively. Important prolyl oligopeptidase inhibition activities were shown by N-methyllaurotetanine (6) and sinoacutine (4) with IC50 values of 135.4 ± 23.2 µM and 143.1 ± 25.4 µM, respectively. Other tested compounds were considered inactive. PMID:25973480

  1. Bromotyrosine Alkaloids with Acetylcholinesterase Inhibitory Activity from the Thai Sponge Acanthodendrilla sp.

    PubMed

    Sirimangkalakitti, Natchanun; Olatunji, Opeyemi J; Changwichit, Kanokwan; Saesong, Tongchai; Chamni, Supakarn; Chanvorachote, Pithi; Ingkaninan, Kornkanok; Plubrukarn, Anuchit; Suwanborirux, Khanit

    2015-11-01

    Twenty bromotyrosine alkaloids, including a new compound, 13-oxosubereamolline D (5), were isolated from the Thai sponge Acanthodendrilla sp. Their structures were determined by analyses of 1D- and 2D-NMR, high-resolution mass, and circular dichroism data. The complete 1H and 13C NMR assignments of 5,7β-dichlorocavernicolin (19) and 5,7α-dichlorocavernicolin (20) are described herein for the first time. The acetylcholinesterase (AChE) inhibitory activity of all isolated compounds was evaluated. Only homoaerothionin (7) and fistularin 1 (10) exhibited inhibitory activity against human recombinant AChE (hrAChE) with IC50s of 4.5 and 47.5 µM, respectively. The hrAChE inhibition kinetics of 7, the most potent alkaloid, showed increased Km and unchanged Vmaxvalues, suggesting its competitive mode of inhibition. The spirocyclohexadienylisoxazole and the length of the alkyl diamine linkage were proposed as the crucial parts for its strong inhibitory activity. This finding indicates a therapeutic potential for 7 in acetylcholine-related diseases, most importantly Alzheimer's disease. PMID:26749833

  2. Effect of pesticide exposure on acetylcholinesterase activity in subsistence farmers from Campeche, Mexico.

    PubMed

    Rendón von Osten, Jaime; Epomex, Centro; Tinoco-Ojanguren, Rolando; Soares, Amadeu M V M; Guilhermino, Lucia

    2004-08-01

    The authors surveyed agricultural production methods and pesticide use among subsistence farmers (campesinos) in 4 rural communities of Campeche, Mexico. Self-reports of symptoms of poisoning resulting from occupational pesticide exposure were elicited by questionnaire (N = 121), and acetylcholinesterase (AChE) activity during insecticide use was evaluated from blood samples (N = 127). In individuals from 2 of the 4 communities, AChE activity was significantly lower (p < 0.05) than the mean of activity determined for individuals in a reference group. Results of this study show that erythrocyte AChE inhibition provides a good biomarker of exposure to organophosphate pesticides in field studies with human populations. Carbamates, particularly carbofuran, seem to be more associated with exuberant and diversified symptomatology of pesticide exposure than organophosphates. Studies in field communities where both carbamates and organophosphates are suspected to exist should include blood AChE determinations, symptomatology surveys, and socioeconomic questionnaires. The authors recommend that the Mexican National Health Ministry authorities specify additional provisions regarding the use of protective equipment and the adoption of other safety practices during field work, increase information campaigns about the risks of pesticide use and the value of safety practices, and increase programs of medical monitoring and assistance for rural communities dealing with pesticides. PMID:16268118

  3. Inhibition of acetylcholinesterase and cytochrome oxidase activity in Fasciola gigantica cercaria by phytoconstituents.

    PubMed

    Sunita, Kumari; Habib, Maria; Kumar, P; Singh, Vinay Kumar; Husain, Syed Akhtar; Singh, D K

    2016-02-01

    Fasciolosis is an important cattle and human disease caused by Fasciola hepatica and Fasciola gigantica. One of the possible methods to control this problem is to interrupt the life cycle of Fasciola by killing its larva (redia and cercaria) in host snail. Molecular identification of cercaria larva of F. gigantica was done by comparing the nucleotide sequencing with adult F. gigantica. It was noted that nucleotide sequencing of cercaria larva and adult F. gigantica were 99% same. Every month during the year 2011-2012, in vivo treatment with 60% of 4 h LC50 of phyto cercaricides citral, ferulic acid, umbelliferone, azadirachtin and allicin caused significant inhibition of acetylcholinesterase (AChE) and cytochrome oxidase activity in the treated cercaria larva of F. gigantica. Whereas, activity of both enzymes were not significantly altered in the nervous tissues of vector snail Lymnaea acuminata exposed to same treatments. Maximum reduction in AChE (1.35% of control in month of June) and cytochrome oxidase (3.71% of control in the month of July) activity were noted in the cercaria exposed to 60% of 4 h LC50 of azadirachtin and allicin, respectively. PMID:26536397

  4. Calcium-activated butyrylcholinesterase in human skin protects acetylcholinesterase against suicide inhibition by neurotoxic organophosphates

    SciTech Connect

    Schallreuter, Karin U.; University of Bradford ). E-mail: K.Schallreuter@bradford.ac.uk; Gibbons, Nicholas C.J.; Elwary, Souna M.; Parkin, Susan M.; Wood, John M.

    2007-04-20

    The human epidermis holds an autocrine acetylcholine production and degradation including functioning membrane integrated and cytosolic butyrylcholinesterase (BuchE). Here we show that BuchE activities increase 9-fold in the presence of calcium (0.5 x 10{sup -3}M) via a specific EF-hand calcium binding site, whereas acetylcholinesterase (AchE) is not affected. {sup 45}Calcium labelling and computer simulation confirmed the presence of one EF-hand binding site per subunit which is disrupted by H{sub 2}O{sub 2}-mediated oxidation. Moreover, we confirmed the faster hydrolysis by calcium-activated BuchE using the neurotoxic organophosphate O-ethyl-O-(4-nitrophenyl)-phenylphosphonothioate (EPN). Considering the large size of the human skin with 1.8 m{sup 2} surface area with its calcium gradient in the 10{sup -3}M range, our results implicate calcium-activated BuchE as a major protective mechanism against suicide inhibition of AchE by organophosphates in this non-neuronal tissue.

  5. Scapaundulin C, a novel labdane diterpenoid isolated from Chinese liverwort Scapania undulate, inhibits acetylcholinesterase activity.

    PubMed

    Kang, Ya-Qi; Zhou, Jin-Chuan; Fan, Pei-Hong; Wang, Shu-Qi; Lou, Hong-Xiang

    2015-12-01

    In the present study, scapaundulin C (1), a new labdane diterpenoid, and four related known compounds scapaundulin A (2), 5α, 8α, 9α-trihydroxy-13E-labden-12-one (3), 5α, 8α-dihydroxy-13E-labden-12-one (4), and (13S)-15-hydroxylabd-8 (17)-en-19-oic acid (5), were isolated from the Chinese liverwort Scapania undulate (L.) Dum., using column chromatography. The structures of these compounds were determined on the basis of 1D- and 2D-NMR analyses. The acetylcholinesterase (AchE) inhibitory activity was evaluated using a bioautographic TLC assay and the cytotoxic activity was evaluated by the MTT method. All the compounds were reported for the first time to exhibit moderate AchE inhibitory activity with minimal inhibitory quantities ranging from 250 to 500 ng. All the compounds were tested for their cytotoxicity against five human tumor cell lines, A549, K562, A2780, Hela, and HT29, and compounds 3 and 4 exhibited moderate inhibitory effects on the growth of A2780 cells. PMID:26721712

  6. Circannual rhythms of acetylcholinesterase (AChE) activity in the freshwater fish Cnesterodon decemmaculatus.

    PubMed

    Menéndez-Helman, Renata J; Ferreyroa, Gisele V; dos Santos Afonso, Maria; Salibián, Alfredo

    2015-01-01

    The use of biomarkers as a tool to assess responses of organisms exposed to pollutants in toxicity bioassays, as well as in aquatic environmental risk assessment protocols, requires the understanding of the natural fluctuation of the particular biomarker. The aim of this study was to characterize the intrinsic variations of acetylcholinesterase (AChE) activity in tissues of a native freshwater teleost fish to be used as biomarker in toxicity tests, taking into account both seasonal influence and fish size. Specific AChE activity was measured by the method of Ellman et al. (1961) in homogenates of fish anterior section finding a seasonal variability. The highest activity was observed in summer, decreasing significantly below 40% in winter. The annual AChE activity cycle in the anterior section was fitted to a sinusoidal function with a period of 11.2 months. Moreover, an inverse relationship between enzymatic activity and the animal size was established. The results showed that both the fish length and seasonal variability affect AChE activity. AChE activity in fish posterior section showed a similar trend to that in the anterior section, while seasonal variations of the activity in midsection were observed but differences were not statistically significant. In addition, no relationship between AChE and total tissue protein was established in the anterior and posterior sections suggesting that the circannual rhythms observed are AChE-specific responses. Results highlight the importance of considering both the fish size and season variations to reach valid conclusions when AChE activity is employed as neurotoxicity biomarker. PMID:25450939

  7. [Effect of acetylcholine and acetylcholinesterase on the activity of contractile vacuole of Amoeba proteus].

    PubMed

    Bagrov, Ia Iu; Manusova, N B

    2011-01-01

    Acetylcholine (ACh, 1 microM) stimulates activity of the contractile vacuole of proteus. The effect of ACh is not mimicked by its analogs which are not hydrolyzed by acetylcholinesterase (AChE), i. e., carbacholine and 5-methylfurmethide. The effect of ACh is not sensitive to the blocking action of M-cholinolytics, atropine and mytolone, but is suppressed by N-cholinolytic, tubocurarine. The inhibitors of AChE, eserine (0.01 microM) and armine (0.1 microM), suppress the effect of ACh on amoeba contractile vacuole. ACh does not affect activation of contractile vacuole induced by arginine-vasopressin (1 microM), but it blocks such effect of opiate receptors agonist, dynorphin A1-13 (0.01 microM). This effect of ACh is also suppressed by the inhibitors of AChE. These results suggest that, in the above-described effects of ACh, AChE acts not as an antagonist, but rather as a synergist. PMID:21870511

  8. Maternal caffeine exposure alters neuromotor development and hippocampus acetylcholinesterase activity in rat offspring.

    PubMed

    Souza, Ana Claudia; Souza, Andressa; Medeiros, Liciane Fernandes; De Oliveira, Carla; Scarabelot, Vanessa Leal; Da Silva, Rosane Souza; Bogo, Mauricio Reis; Capiotti, Katiucia Marques; Kist, Luiza Wilges; Bonan, Carla D; Caumo, Wolnei; Torres, Iraci L S

    2015-01-21

    The objective of this study was to evaluate the effects of maternal caffeine intake on the neuromotor development of rat offspring and on acetylcholine degradation and acetylcholinesterase (AChE) expression in the hippocampus of 14-day-old infant rats. Rat dams were treated with caffeine (0.3g/L) throughout gestation and lactation until the pups were 14 days old. The pups were divided into three groups: (1) control, (2) caffeine, and (3) washout caffeine. The washout group received a caffeine solution until the seventh postnatal day (P7). Righting reflex (RR) and negative geotaxis (NG) were assessed to evaluate postural parameters as an index of neuromotor reflexes. An open-field (OF) test was conducted to assess locomotor and exploratory activities as well as anxiety-like behaviors. Caffeine treatment increased both RR and NG latency times. In the OF test, the caffeine group had fewer outer crossings and reduced locomotion compared to control, while the washout group showed increased inner crossings in relation to the other groups and fewer rearings only in comparison to the control group. We found decreased AChE activity in the caffeine group compared to the other groups, with no alteration in AChE transcriptional regulation. Chronic maternal exposure to caffeine promotes important alterations in neuromotor development. These results highlight the ability of maternal caffeine intake to interfere with cholinergic neurotransmission during brain development. PMID:25451122

  9. Methionine-choline deprivation alters liver and brain acetylcholinesterase activity in C57BL6 mice.

    PubMed

    Vučević, Danijela B; Cerović, Ivana B; Mladenović, Dušan R; Vesković, Milena N; Stevanović, Ivana; Jorgačević, Bojan Z; Ješić Vukićević, Rada; Radosavljević, Tatjana S

    2016-07-01

    Choline and methionine are precursors of acetylcholine, whose hydrolysis is catalyzed by acetylcholinesterase (AChE). Considering the possibility of their common deficiency, we investigated the influence of methionine-choline deprivation on AChE activity in liver and various brain regions (hypothalamus, hippocampus, cerebral cortex and striatum) in mice fed with methionine-choline deficient (MCD) diet. Male C57BL/6 mice (n = 28) were randomly and equally divided into following groups: control group fed with standard diet for 6 weeks (C) and groups fed with MCD diet for 2 weeks (MCD2), 4 weeks (MCD4) and for 6 weeks (MCD6). After the diet, mice were sacrificied and AChE activity in liver and brain was determined spectrophotometrically. Hepatic AChE activity was higher in MCD2, MCD4 and MCD6 compared to control (p < 0.01), with most prominent increase in MCD6. AChE activity in hypothalamus was higher in MCD4 and MCD6 vs. control (p < 0.05 and p < 0.01, respectively), as well as in MCD6 compared to MCD4 (p < 0.01). In hippocampus, increase in AChE activity was shown in MCD6 compared to control (p < 0.01). In cortex and striatum, increase in AChE activity was noted in MCD6 compared to control (p < 0.05). Our findings indicate the increase of hepatic and brain AChE activity in mice caused by methionine-choline deprivation. PMID:27174897

  10. Flavonoids, Antioxidant Potential, and Acetylcholinesterase Inhibition Activity of the Extracts from the Gametophyte and Archegoniophore of Marchantia polymorpha L.

    PubMed

    Wang, Xin; Cao, Jianguo; Wu, Yuhuan; Wang, Quanxi; Xiao, Jianbo

    2016-01-01

    Marchantia polymorpha L. is a representative bryophyte used as a traditional Chinese medicinal herb for scald and pneumonia. The phytochemicals in M. polymorpha L. are terpenoids and flavonoids, among which especially the flavonoids show significant human health benefits. Many researches on the gametophyte of M. polymorpha L. have been reported. However, as the reproductive organ of M. polymorpha L., the bioactivity and flavonoids profile of the archegoniophore have not been reported, so in this work the flavonoid profiles, antioxidant and acetylcholinesterase inhibition activities of the extracts from the archegoniophore and gametophyte of M. polymorpha L. were compared by radical scavenging assay methods (DPPH, ABTS, O(2-)), reducing power assay, acetylcholinesterase inhibition assay and LC-MS analysis. The results showed that the total flavonoids content in the archegoniophore was about 10-time higher than that of the gametophyte. Differences between the archegoniophore and gametophyte of M. polymorpha L. were observed by LC-MS analysis. The archegoniophore extracts showed stronger bio-activities than those of the gametophyte. The archegoniophore extract showed a significant acetylcholinesterase inhibition, while the gametophyte extract hardly inhibited it. PMID:26999088

  11. Cinnamomum loureirii Extract Inhibits Acetylcholinesterase Activity and Ameliorates Trimethyltin-Induced Cognitive Dysfunction in Mice.

    PubMed

    Kim, Cho Rong; Choi, Soo Jung; Kwon, Yoon Kyung; Kim, Jae Kyeom; Kim, Youn-Jung; Park, Gwi Gun; Shin, Dong-Hoon

    2016-01-01

    The pathogenesis of Alzheimer's disease (AD) has been linked to the deficiency of neurotransmitter acetylcholine (ACh) in the brain, and the main treatment strategy for improving AD symptoms is the inhibition of acetylcholinesterase (AChE) activity. In the present study, we aimed to identify potent AChE inhibitors from Cinnamomum loureirii extract via bioassay-guided fractionation. We demonstrated that the most potent AChE inhibitor present in the C. loureirii extract was 2,4-bis(1,1-dimethylethyl)phenol. To confirm the antiamnesic effects of the ethanol extract of C. loureirii, mice were intraperitoneally injected with the neurotoxin trimethyltin (2.5 mg/kg) to induce cognitive dysfunction, and performance in the Y-maze and passive avoidance tests was assessed. Treatment with C. loureirii extract significantly improved performance in both behavioral tests, suggesting that this extract may be neuroprotective and therefore beneficial in preventing or ameliorating the degenerative processes of AD, potentially by restoring cholinergic function. PMID:27374288

  12. Blocked Enzymatic Etching of Gold Nanorods: Application to Colorimetric Detection of Acetylcholinesterase Activity and Its Inhibitors.

    PubMed

    Saa, Laura; Grinyte, Ruta; Sánchez-Iglesias, Ana; Liz-Marzán, Luis M; Pavlov, Valeri

    2016-05-01

    The anisotropic morphology of gold nanorods (AuNRs) has been shown to lead to nonuniform ligand distribution and preferential etching through their tips. We have recently demonstrated that this effect can be achieved by biocatalytic oxidation with hydrogen peroxide, catalyzed by the enzyme horseradish peroxidase (HRP). We report here that modification of AuNRs with thiol-containing organic molecules such as glutathione and thiocholine hinders enzymatic AuNR etching. Higher concentrations of thiol-containing molecules in the reaction mixture gradually decrease the rate of enzymatic etching, which can be monitored by UV-vis spectroscopy through changes in the AuNR longitudinal plasmon band. This effect can be applied to develop novel optical assays for acetylcholinesterase (AChE) activity. The biocatalytic hydrolysis of acetylthiocholine by AChE yields thiocholine, which prevents enzymatic AuNR etching in the presence of HRP. Additionally, the same bioassay can be used for the detection of nanomolar concentrations of AChE inhibitors such as paraoxon and galanthamine. PMID:27070402

  13. Acetylcholinesterase Inhibitory Activity of Pigment Echinochrome A from Sea Urchin Scaphechinus mirabilis

    PubMed Central

    Lee, Sung Ryul; Pronto, Julius Ryan D.; Sarankhuu, Bolor-Erdene; Ko, Kyung Soo; Rhee, Byoung Doo; Kim, Nari; Mishchenko, Natalia P.; Fedoreyev, Sergey A.; Stonik, Valentin A.; Han, Jin

    2014-01-01

    Echinochrome A (EchA) is a dark-red pigment of the polyhydroxynaphthoquinone class isolated from sea urchin Scaphechinus mirabilis. Acetylcholinesterase (AChE) inhibitors are used in the treatment of various neuromuscular disorders, and are considered as strong therapeutic agents for the treatment of Alzheimer’s disease (AD). Although EchA is clinically used to treat ophthalmic diseases and limit infarct formation during ischemia/reperfusion injury, anti-AChE effect of EchA is still unknown. In this study, we investigated the anti-AChE effect of EchA in vitro. EchA and its exhausted form which lost anti-oxidant capacity did not show any significant cytotoxicy on the H9c2 and A7r5 cells. EchA inhibited AChE with an irreversible and uncompetitive mode. In addition, EchA showed reactive oxygen species scavenging activity, particularly with nitric oxide. These findings indicate new therapeutic potential for EchA in treating reduced acetylcholine-related diseases including AD and provide an insight into developing new AChE inhibitors. PMID:24918454

  14. Acetylcholinesterase inhibitory activity of pigment echinochrome A from sea urchin Scaphechinus mirabilis.

    PubMed

    Lee, Sung Ryul; Pronto, Julius Ryan D; Sarankhuu, Bolor-Erdene; Ko, Kyung Soo; Rhee, Byoung Doo; Kim, Nari; Mishchenko, Natalia P; Fedoreyev, Sergey A; Stonik, Valentin A; Han, Jin

    2014-06-01

    Echinochrome A (EchA) is a dark-red pigment of the polyhydroxynaphthoquinone class isolated from sea urchin Scaphechinus mirabilis. Acetylcholinesterase (AChE) inhibitors are used in the treatment of various neuromuscular disorders, and are considered as strong therapeutic agents for the treatment of Alzheimer's disease (AD). Although EchA is clinically used to treat ophthalmic diseases and limit infarct formation during ischemia/ reperfusion injury, anti-AChE effect of EchA is still unknown. In this study, we investigated the anti-AChE effect of EchA in vitro. EchA and its exhausted form which lost anti-oxidant capacity did not show any significant cytotoxicy on the H9c2 and A7r5 cells. EchA inhibited AChE with an irreversible and uncompetitive mode. In addition, EchA showed reactive oxygen species scavenging activity, particularly with nitric oxide. These findings indicate new therapeutic potential for EchA in treating reduced acetylcholine-related diseases including AD and provide an insight into developing new AChE inhibitors. PMID:24918454

  15. Characterization of Lignanamides from Hemp (Cannabis sativa L.) Seed and Their Antioxidant and Acetylcholinesterase Inhibitory Activities.

    PubMed

    Yan, Xiaoli; Tang, Jiajing; dos Santos Passos, Carolina; Nurisso, Alessandra; Simões-Pires, Claudia Avello; Ji, Mei; Lou, Hongxiang; Fan, Peihong

    2015-12-16

    Hemp seed is known for its content of fatty acids, proteins, and fiber, which contribute to its nutritional value. Here we studied the secondary metabolites of hemp seed aiming at identifying bioactive compounds that could contribute to its health benefits. This investigation led to the isolation of 4 new lignanamides, cannabisin M (2), cannabisin N (5), cannabisin O (8), and 3,3'-demethyl-heliotropamide (10), together with 10 known lignanamides, among which 4 was identified for the first time from hemp seed. Structures were established on the basis of NMR, HR-MS, UV, and IR as well as by comparison with the literature data. Lignanamides 2, 7, and 9-14 showed good antioxidant activity, among which 7, 10, and 13 also inhibited acetylcholinesterase in vitro. The newly identified compounds in this study add to the diversity of hemp seed composition, and the bioassays implied that hemp seed, with lignanamides as nutrients, may be a good source of bioactive and protective compounds. PMID:26585089

  16. Design and prediction of new acetylcholinesterase inhibitor via quantitative structure activity relationship of huprines derivatives.

    PubMed

    Zhang, Shuqun; Hou, Bo; Yang, Huaiyu; Zuo, Zhili

    2016-05-01

    Acetylcholinesterase (AChE) is an important enzyme in the pathogenesis of Alzheimer's disease (AD). Comparative quantitative structure-activity relationship (QSAR) analyses on some huprines inhibitors against AChE were carried out using comparative molecular field analysis (CoMFA), comparative molecular similarity indices analysis (CoMSIA), and hologram QSAR (HQSAR) methods. Three highly predictive QSAR models were constructed successfully based on the training set. The CoMFA, CoMSIA, and HQSAR models have values of r (2) = 0.988, q (2) = 0.757, ONC = 6; r (2) = 0.966, q (2) = 0.645, ONC = 5; and r (2) = 0.957, q (2) = 0.736, ONC = 6. The predictabilities were validated using an external test sets, and the predictive r (2) values obtained by the three models were 0.984, 0.973, and 0.783, respectively. The analysis was performed by combining the CoMFA and CoMSIA field distributions with the active sites of the AChE to further understand the vital interactions between huprines and the protease. On the basis of the QSAR study, 14 new potent molecules have been designed and six of them are predicted to be more active than the best active compound 24 described in the literature. The final QSAR models could be helpful in design and development of novel active AChE inhibitors. PMID:26832327

  17. Age-dependent modulation of fasting and long-term dietary restriction on acetylcholinesterase in non-neuronal tissues of mice.

    PubMed

    Suchiang, Kitlangki; Sharma, Ramesh

    2016-08-01

    Dietary restriction (DR) without malnutrition is a robust intervention that extends lifespan and slows the onset of nervous system deficit and age-related diseases in diverse organisms. Acetylcholinesterase (AChE), a thoroughly studied enzyme better known for hydrolyzing acetylcholine (ACh) in neuronal tissues, has recently been linked with multiple unrelated biological functions in different non-neuronal tissues. In the present study, the activity and protein expression level of AChE in liver, heart, and kidney of young (1 month), adult (6 month), and aged (18 month) mice were investigated. We also studied age- and tissue-specific changes in AChE activity and protein expression level after the mice were subjected to 24-h fasting and long-term DR. Our results showed that AChE activity and protein expression in kidney and heart of aged mice decreased significantly in comparison with young mice. On the contrary, long-term DR decreases the AChE activity and the protein expression level in all tissues irrespective of ages studied. We summarized that changes in AChE with age in different tissues studied reflects its different roles at different phases of an organism's life. Conversely, the cumulative modulation manifested in the form of lowering AChE by long-term DR may prevent the futile synthesis and accumulation of unwanted AChE besides the added compensatory benefit of enhanced ACh availability needed during the period of starvation. This, in turn, may help in preventing the declining homeostatic roles of this important neurotransmitter in different tissues. PMID:27379505

  18. Acetylcholinesterase Activity, Cohabitation with Floricultural Workers, and Blood Pressure in Ecuadorian Children

    PubMed Central

    Jacobs, David R.; Himes, John H.; Alexander, Bruce H.

    2013-01-01

    Background: Acetylcholinesterase (AChE) inhibitors are commonly used pesticides that can effect hemodynamic changes through increased cholinergic stimulation. Children of agricultural workers are likely to have paraoccupational exposures to pesticides, but the potential physiological impact of such exposures is unclear. Objectives: We investigated whether secondary pesticide exposures were associated with blood pressure and heart rate among children living in agricultural Ecuadorian communities. Methods: This cross-sectional study included 271 children 4–9 years of age [51% cohabited with one or more flower plantation workers (mean duration, 5.2 years)]. Erythrocyte AChE activity was measured using the EQM Test-mate system. Linear regression models were used to estimate associations of systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate with AChE activity, living with flower workers, duration of cohabitation with a flower worker, number of flower workers in the child’s home, and number of practices that might increase children’s exposure to pesticides. Results: Mean (± SD) AChE activity was 3.14 ± 0.49 U/mL. A 1-U/mL decrease in AChE activity was associated with a 2.86-mmHg decrease in SBP (95% CI: –5.20, –0.53) and a 2.89-mmHg decrease in DBP (95% CI: –5.00, –0.78), after adjustment for potential confounders. Children living with flower workers had lower SBP (–1.72 mmHg; 95% CI: –3.53, 0.08) than other children, and practices that might increase exposure also were associated with lower SBP. No significant associations were found between exposures and heart rate. Conclusions: Our findings suggest that subclinical secondary exposures to pesticides may affect vascular reactivity in children. Additional research is needed to confirm these findings. PMID:23359481

  19. Effect of Chlorpyrifos Ethyl on Acetylcholinesterase Activity in Climbing Perch (Anabas testudineus, Bloch, 1972).

    PubMed

    Tam, Nguyen Thanh; Berg, Håkan; Tuyen, Phan Thi Bich; Van Cong, Nguyen

    2015-11-01

    The high use of pesticides in intensive rice farming in the Mekong Delta constitutes a potential hazard to the environment and to people's health. Chlorpyrifos ethyl (CPF) is a commonly used organophosphate (OP) insecticide, but information about its potential negative impacts on the aquatic environment in the Mekong Delta is scarce. Both acute and subacute toxicity tests were performed in a static nonrenewable system to investigate the effects of CPF on brain acetylcholinesterase (AChE) activity in native climbing perch fingerlings (Anabas testudineus, Bloch, 1972). Environmental parameters, such as dissolved oxygen, water temperature, and pH, were similar to field conditions in the Mekong Delta. In a 96-h lethal concentration (LC50) test, fingerlings of climbing perch were randomly exposed to five levels of CPF ranging from 0.8 to 4.5 ppm. Five sublethal levels of CPF (1, 5, 10, 15, and 20 % of the 96-h LC50 value) were tested to assess the sensitivity and recovery of the brain AChE activity in climbing perch fingerlings exposed to CPF. The results showed that CPF were moderately toxic to climbing perch with a 96-h median LC50 of 1.73 ppm. CPF also caused long-term AChE inhibition with 70 % inhibition remaining after 96 h for the four highest test concentrations. The recovery of brain AChE activity in fish placed in CPF-free water was very slow, and after 7 days the brain AChE activity was still significant lower in fish from the four highest concentrations compared with the control. The results from this study indicate that OP insecticides, such as CPF, can have long-lasting sublethal effects on aquatic species in the Mekong Delta. PMID:26135300

  20. Copper acutely impairs behavioral function and muscle acetylcholinesterase activity in zebrafish (Danio rerio).

    PubMed

    Haverroth, Gabriela M B; Welang, Chariane; Mocelin, Riciéri N; Postay, Daniela; Bertoncello, Kanandra T; Franscescon, Francini; Rosemberg, Denis B; Dal Magro, Jacir; Dalla Corte, Cristiane L

    2015-12-01

    Copper is a heavy metal found at relatively high concentrations in surface waters around the world. Copper is a micronutrient at low concentrations and is essential to several organisms. At higher concentrations copper can become toxic, which reveal the importance of studying the toxic effects of this metal on the aquatic life. Thus, the objective of this study was to evaluate the toxic effects of copper on the behavior and biochemical parameters of zebrafish (Danio rerio). Zebrafish were exposed for 24h at a concentration of 0.006 mg/L Cu. After the exposure period, behavioral profile of animals was recorded through 6 min using two different apparatuses tests: the Novel Tank and the Light-Dark test. After behavioral testing, animals were euthanized with a solution of 250 mg/L of tricaine (MS-222). Brain, muscle, liver and gills were extracted for analysis of parameters related to oxidative stress and accumulation of copper in these tissues. Acetylcholinesterase (AChE) activity was determined in brain and muscle. Results showed acute exposure to copper induces significant changes in behavioral profile of zebrafish by changing locomotion and natural tendency to avoid brightly lit area. On the other hand, there were no significant effects on parameters related to oxidative stress. AChE activity decreased significantly in zebrafish muscle, but there were no significant changes in cerebral AChE activity. Copper levels in tissues did not increase significantly compared to the controls. Taken together, these results indicate that a low concentration of copper can acutely affect behavioral profile of adult zebrafish which could be partially related to an inhibition on muscle AChE activity. These results reinforce the need of additional tests to establishment of safe copper concentrations to aquatic organisms and the importance of behavioral parameters in ecotoxicological studies. PMID:26386335

  1. Acetylcholinesterase active centre and gorge conformations analysed by combinatorial mutations and enantiomeric phosphonates.

    PubMed Central

    Kovarik, Zrinka; Radić, Zoran; Berman, Harvey A; Simeon-Rudolf, Vera; Reiner, Elsa; Taylor, Palmer

    2003-01-01

    A series of eight double and triple mutants of mouse acetylcholinesterase (AChE; EC 3.1.1.7), with substitutions corresponding to residues found largely within the butyrylcholinesterase (BChE; EC 3.1.1.8) active-centre gorge, was analysed to compare steady-state kinetic constants for substrate turnover and inhibition parameters for enantiomeric methylphosphonate esters. The mutations combined substitutions in the acyl pocket (Phe(295)-->Leu and Phe(297)-->Ile) with the choline-binding site (Tyr(337)-->Ala and Phe(338)-->Ala) and with a side chain (Glu(202)--> Gln) N-terminal to the active-site serine, Ser(203). The mutations affected catalysis by increasing K (m) and decreasing k (cat), but these constants were typically affected by an order of magnitude or less, a relatively small change compared with the catalytic potential of AChE. To analyse the constraints on stereoselective phosphonylation, the mutant enzymes were reacted with a congeneric series of S (P)- and R (P)-methylphosphonates of known absolute stereochemistry. Where possible, the overall reaction rates were deconstructed into the primary constants for formation of the reversible complex and intrinsic phosphonylation. The multiple mutations greatly reduced the reaction rates of the more reactive S (P)-methylphosphonates, whereas the rates of reaction with the R (P)-methylphosphonates were markedly enhanced. With the phosphonates of larger steric bulk, the enhancement of rates for the R (P) enantiomers, coupled with the reduction of the S (P) enantiomers, was sufficient to invert markedly the enantiomeric preference. The sequence of mutations to enlarge the size of the AChE active-centre gorge, resembling in part the more spacious gorge of BChE, did not show an ordered conversion into BChE reactivity as anticipated for a rigid template. Rather, the individual aromatic residues may mutually interact to confer a distinctive stereospecificity pattern towards organophosphates. PMID:12665427

  2. Transcriptional activity of acetylcholinesterase gene is regulated by DNA methylation during C2C12 myogenesis.

    PubMed

    Lau, Kei M; Gong, Amy G W; Xu, Miranda L; Lam, Candy T W; Zhang, Laura M L; Bi, Cathy W C; Cui, D; Cheng, Anthony W M; Dong, Tina T X; Tsim, Karl W K; Lin, Huangquan

    2016-07-01

    The expression of acetylcholinesterase (AChE), an enzyme hydrolyzes neurotransmitter acetylcholine at vertebrate neuromuscular junction, is regulated during myogenesis, indicating the significance of muscle intrinsic factors in controlling the enzyme expression. DNA methylation is essential for temporal control of myogenic gene expression during myogenesis; however, its role in AChE regulation is not known. The promoter of vertebrate ACHE gene carries highly conserved CG-rich regions, implying its likeliness to be methylated for epigenetic regulation. A DNA methyltransferase inhibitor, 5-azacytidine (5-Aza), was applied onto C2C12 cells throughout the myotube formation. When DNA methylation was inhibited, the promoter activity, transcript expression and enzymatic activity of AChE were markedly increased after day 3 of differentiation, which indicated the putative role of DNA methylation. By bisulfite pyrosequencing, the overall methylation rate was found to peak at day 3 during C2C12 cell differentiation; a SP1 site located at -1826bp upstream of mouse ACHE gene was revealed to be heavily methylated. The involvement of transcriptional factor SP1 in epigenetic regulation of AChE was illustrated here: (i) the SP1-driven transcriptional activity was increased in 5-Aza-treated C2C12 culture; (ii) the binding of SP1 onto the SP1 site of ACHE gene was fully blocked by the DNA methylation; and (iii) the sequence flanking SP1 sites of ACHE gene was precipitated by chromatin immuno-precipitation assay. The findings suggested the role of DNA methylation on AChE transcriptional regulation and provided insight in elucidating the DNA methylation-mediated regulatory mechanism on AChE expression during muscle differentiation. PMID:27021952

  3. Chlorpyrifos and Chlorpyrifos-Oxon Inhibit Axonal Growth by Interfering with the Morphogenic Activity of Acetylcholinesterase

    PubMed Central

    Yang, Dongren; Howard, Angela; Bruun, Donald; Ajua-Alemanj, Mispa; Pickart, Cecile; Lein, Pamela J.

    2008-01-01

    A primary role of acetylcholinesterase (AChE) is regulation of cholinergic neurotransmission by hydrolysis of synaptic acetylcholine. In the developing nervous system, however, AChE also functions as a morphogenic factor to promote axonal growth. This raises the question of whether organophosphorus pesticides (OPs) that are known to selectively bind to and inactivate the enzymatic function of AChE also interfere with its morphogenic function to perturb axonogenesis. To test this hypothesis, we exposed primary cultures of sensory neurons derived from embryonic rat dorsal root ganglia (DRG) to chlorpyrifos (CPF) or its oxon metabolite (CPFO). Both OPs significantly decreased axonal length at concentrations that had no effect on cell viability, protein synthesis or the enzymatic activity of AChE. Comparative analyses of the effects of CPF and CPFO on axonal growth in DRG neurons cultured from AChE nullizygous (AChE−/−) versus wildtype (AChE+/+) mice indicated that while these OPs inhibited axonal growth in AChE+/+ DRG neurons, they had no effect on axonal growth in AChE−/− DRG neurons. However, transfection of AChE−/− DRG neurons with cDNA encoding full-length AChE restored the wildtype response to the axon inhibitory effects of OPs. These data indicate that inhibition of axonal growth by OPs requires AChE, but the mechanism involves inhibition of the morphogenic rather than enzymatic activity of AChE. These findings suggest a novel mechanism for explaining not only the functional deficits observed in children and animals following developmental exposure to OPs, but also the increased vulnerability of the developing nervous system to OPs. PMID:18076960

  4. Interpretation of toxicological activity of ionic liquids to acetylcholinesterase inhibition via in silico modelling.

    PubMed

    Cho, Chul-Woong; Yun, Yeoung-Sang

    2016-09-01

    For designing environmentally friendly ionic liquids (ILs), their structural effects on the toxicity should be interpreted via modelling based on the quantitative-structure-activity-relationship (QSAR) concept. For the purpose, QSAR models for predicting IL toxicity in acetylcholinesterase activity were developed by using linear free-energy relationship (LFER) descriptors, whose chemical meanings are well defined. These are excess molar refraction (Ec or a), dipolarity/polarizability (Sc or a), H-bonding acidity (Ac or a), H-bonding basicity (Bc or a), McGowan volume (Vc or a), and ionic interactions of cation (J(+)) and anion (J(-)). Since the experimentally determined LFER descriptors are not available, we calculated them based on density functional theory, conductor-like screening model and the open-source software, obprop. The toxicity values of imidazolium- and pyridinium-based ILs could be predicted by a combination of four descriptors (Ac, Bc, Vc and Sa) with an R(2) of 0.828, and (Ec, Ac, Ea and Sa) with an R(2) of 0.879, respectively. In prediction study using the overall dataset containing various IL structures, the six calculated terms (Ec, Sc, Ac, J(+), Ea, and Sa) were selected and correlated with the observed toxicity values in R(2) of 0.748 for the training set, R(2) of 0.711 for the test set and R(2) of 0.655 for external validation set. And this study explains how the selected terms are contributing to the prediction models, and their chemical meanings were understood. PMID:27289204

  5. In vitro inhibitory effect of aflatoxin B1 on acetylcholinesterase activity in mouse brain.

    PubMed

    Cometa, Maria Francesca; Lorenzini, Paola; Fortuna, Stefano; Volpe, Maria Teresa; Meneguz, Annarita; Palmery, Maura

    2005-01-01

    Growing concern on the problem of mycotoxins in the alimentary chain underlines the need to investigate the mechanisms explaining the cholinergic effects of aflatoxin B(1) (AFB(1)). We examined the effect of AFB(1), a mycotoxin produced by Aspergillus flavus, on mouse brain acetylcholinesterase (AChE) and specifically on its molecular isoforms (G(1) and G(4)) after in vitro exposure. AFB(1) (from 10(-9) to 10(-4)M), inhibited mouse brain AChE activity (IC(50) = 31.6 x 10(-6)M) and its G(1) and G(4) molecular isoforms in a dose-dependent manner. Michaelis-Menten parameters indicate that the K(m) value increased from 55.2 to 232.2% whereas V(max) decreased by 46.2-75.1%. The direct, the Lineweaver-Burk and the secondary plots indicated a non-competitive-mixed type antagonism, induced when the inhibitor binds to the free enzyme and to the enzyme-substrate complex. AFB(1)-inhibited AChE was partially reactivated by pyridine 2-aldoxime (2-PAM) (10(-4)M) but the AChE-inhibiting time courses of AFB(1) (10(-4)M) and diisopropylfluorophosphate (DFP) (2 x 10(-7)M) differed. Overall these data suggest that AFB(1) non-competitively inhibits mouse brain AChE by blocking access of the substrate to the active site or by inducing a defective conformational change in the enzyme through non-covalent binding interacting with the AChE peripheral binding site, or through both mechanisms. PMID:15590113

  6. Chlorpyrifos and chlorpyrifos-oxon inhibit axonal growth by interfering with the morphogenic activity of acetylcholinesterase

    SciTech Connect

    Yang Dongren; Howard, Angela; Bruun, Donald; Ajua-Alemanj, Mispa; Pickart, Cecile; Lein, Pamela J.

    2008-04-01

    A primary role of acetylcholinesterase (AChE) is regulation of cholinergic neurotransmission by hydrolysis of synaptic acetylcholine. In the developing nervous system, however, AChE also functions as a morphogenic factor to promote axonal growth. This raises the question of whether organophosphorus pesticides (OPs) that are known to selectively bind to and inactivate the enzymatic function of AChE also interfere with its morphogenic function to perturb axonogenesis. To test this hypothesis, we exposed primary cultures of sensory neurons derived from embryonic rat dorsal root ganglia (DRG) to chlorpyrifos (CPF) or its oxon metabolite (CPFO). Both OPs significantly decreased axonal length at concentrations that had no effect on cell viability, protein synthesis or the enzymatic activity of AChE. Comparative analyses of the effects of CPF and CPFO on axonal growth in DRG neurons cultured from AChE nullizygous (AChE{sup -/-}) versus wild type (AChE{sup +/+}) mice indicated that while these OPs inhibited axonal growth in AChE{sup +/+} DRG neurons, they had no effect on axonal growth in AChE{sup -/-} DRG neurons. However, transfection of AChE{sup -/-} DRG neurons with cDNA encoding full-length AChE restored the wild type response to the axon inhibitory effects of OPs. These data indicate that inhibition of axonal growth by OPs requires AChE, but the mechanism involves inhibition of the morphogenic rather than enzymatic activity of AChE. These findings suggest a novel mechanism for explaining not only the functional deficits observed in children and animals following developmental exposure to OPs, but also the increased vulnerability of the developing nervous system to OPs.

  7. Chemical constituents from Sonneratia ovata Backer and their in vitro cytotoxicity and acetylcholinesterase inhibitory activities.

    PubMed

    Nguyen, Thi-Hoai-Thu; Pham, Huu-Viet-Thong; Pham, Nguyen-Kim-Tuyen; Quach, Ngo-Diem-Phuong; Pudhom, Khanitha; Hansen, Poul Erik; Nguyen, Kim-Phi-Phung

    2015-06-01

    Sonneratia ovata Backer, Sonneratiaceae, is a widespread plant in mangrove forests in Vietnam, Cambodia, Thailand, Indonesia. Sonneratia ovata's chemical composition remains mostly unknown. Therefore, we now report on the structural elucidation of three new phenolics, sonnerphenolic A (1), sonnerphenolic B (2), and sonnerphenolic C (23), a new cerebroside, sonnercerebroside (3) together with nineteen known compounds, including nine lignans (5-13), two steroids (14, 15), two triterpenoids (16, 17), three gallic acid derivatives (18-20), two phenolic derivatives (4, 22) and a 1-O-benzyl-β-d-glucopyranose (21) isolated from the leaves of Sonneratia ovata. Their chemical structures were established by spectroscopic data, as well as high resolution mass spectra and comparison with literature data. The in vitro acetylcholinesterase (AChE) inhibition and cytotoxic activities against HeLa (human epithelial carcinoma), NCI-H460 (human lung cancer), MCF-7 (human breast cancer) cancer cell lines and PHF (primary human fibroblast) cell were evaluated on some extracts and purified compounds at a concentration of 100 μg/mL. Compounds (5, 6, 23) exhibited cytotoxicity against the MCF-7 cell line with the IC50 values of 146.9±9.0, 114.5±7.2, and 112.8±9.4 μM, respectively, while they showed nontoxic with the normal cell (PHF) with IC50s >277 μM. Among 15 tested compounds, (S)-rhodolatouchol (22) showed inhibition against AChE with an IC50 value of 96.1±14.5 μM. PMID:25933595

  8. Molecular Dynamics of Acetylcholinesterase

    SciTech Connect

    Shen, T Y.; Tai, Kaihsu; Henchman, Richard H.; Mccammon, Andy

    2002-06-01

    Molecular dynamics simulations are leading to a deeper understanding of the activity of the enzyme acetylcholinesterase. Simulations have shown how breathing motions in the enzyme facilitate the displacement of substrate from the surface of the enzyme to the buried active site. The most recent work points to the complex and spatially extensive nature of such motions and suggests possible modes of regulation of the activity of the enzyme.

  9. Subchronic atrazine exposure changes defensive behaviour profile and disrupts brain acetylcholinesterase activity of zebrafish.

    PubMed

    Schmidel, Ademir J; Assmann, Karla L; Werlang, Chariane C; Bertoncello, Kanandra T; Francescon, Francini; Rambo, Cassiano L; Beltrame, Gabriela M; Calegari, Daiane; Batista, Cibele B; Blaser, Rachel E; Roman Júnior, Walter A; Conterato, Greicy M M; Piato, Angelo L; Zanatta, Leila; Magro, Jacir Dal; Rosemberg, Denis B

    2014-01-01

    Animal behaviour is the interaction between environment and an individual organism, which also can be influenced by its neighbours. Variations in environmental conditions, as those caused by contaminants, may lead to neurochemical impairments altering the pattern of the behavioural repertoire of the species. Atrazine (ATZ) is an herbicide widely used in agriculture that is frequently detected in surface water, affecting non-target species. The zebrafish is a valuable model organism to assess behavioural and neurochemical effects of different contaminants since it presents a robust behavioural repertoire and also all major neurotransmitter systems described for mammalian species. The goal of this study was to evaluate the effects of subchronic ATZ exposure in defensive behaviours of zebrafish (shoaling, thigmotaxis, and depth preference) using the split depth tank. Furthermore, to investigate a putative role of cholinergic signalling on ATZ-mediated effects, we tested whether this herbicide alters acetylcholinesterase (AChE) activity in brain and muscle preparations. Fish were exposed to ATZ for 14days and the following groups were tested: control (0.2% acetone) and ATZ (10 and 1000μg/L). The behaviour of four animals in the same tank was recorded for 6min and biological samples were prepared. Our results showed that 1000μg/L ATZ significantly increased the inter-fish distance, as well as the nearest and farthest neighbour distances. This group also presented an increase in the shoal area with decreased social interaction. No significant differences were detected for the number of animals in the shallow area, latency to enter the shallow and time spent in shallow and deep areas of the apparatus, but the ATZ 1000 group spent significantly more time near the walls. Although ATZ did not affect muscular AChE, it significantly reduced AChE activity in brain. Exposure to 10μg/L ATZ did not affect behaviour or AChE activity. These data suggest that ATZ impairs defensive

  10. Acetylcholinesterase inhibition, antioxidant activity and toxicity of Peumus boldus water extracts on HeLa and Caco-2 cell lines.

    PubMed

    Falé, P L; Amaral, F; Amorim Madeira, P J; Sousa Silva, M; Florêncio, M H; Frazão, F N; Serralheiro, M L M

    2012-08-01

    This work aimed to study the inhibition on acetylcholinesterase activity (AChE), the antioxidant activity and the toxicity towards Caco-2 and HeLa cells of aqueous extracts of Peumus Boldus. An IC(50) value of 0.93 mg/mL, for AChE inhibition, and EC(50) of 18.7 μg/mL, for the antioxidant activity, was determined. This activity can be attributed to glycosylated flavonoid derivatives detected, which were the main compounds, although boldine and other aporphine derivatives were also present. No changes in the chemical composition or the biochemical activities were found after gastrointestinal digestion. Toxicity of P. boldus decoction gave an IC(50) value 0.66 mg/mL for HeLa cells, which caused significant changes in the cell proteome profile. PMID:22617353

  11. Intraperitoneal Exposure to Nano/Microparticles of Fullerene (C60) Increases Acetylcholinesterase Activity and Lipid Peroxidation in Adult Zebrafish (Danio rerio) Brain

    PubMed Central

    Dal Forno, Gonzalo Ogliari; Kist, Luiza Wilges; de Azevedo, Mariana Barbieri; Fritsch, Rachel Seemann; Pereira, Talita Carneiro Brandão; Britto, Roberta Socoowski; Guterres, Sílvia Stanisçuaski; Külkamp-Guerreiro, Irene Clemes; Bonan, Carla Denise; Monserrat, José María; Bogo, Maurício Reis

    2013-01-01

    Even though technologies involving nano/microparticles have great potential, it is crucial to determine possible toxicity of these technological products before extensive use. Fullerenes C60 are nanomaterials with unique physicochemical and biological properties that are important for the development of many technological applications. The aim of this study was to evaluate the consequences of nonphotoexcited fullerene C60 exposure in brain acetylcholinesterase expression and activity, antioxidant responses, and oxidative damage using adult zebrafish as an animal model. None of the doses tested (7.5, 15, and 30 mg/kg) altered AChE activity, antioxidant responses, and oxidative damage when zebrafish were exposed to nonphotoexcited C60 nano/microparticles during 6 and 12 hours. However, adult zebrafish exposed to the 30 mg/kg dose for 24 hours have shown enhanced AChE activity and augmented lipid peroxidation (TBARS assays) in brain. In addition, the up-regulation of brain AChE activity was neither related to the transcriptional control (RT-qPCR analysis) nor to the direct action of nonphotoexcited C60 nano/microparticles on the protein (in vitro results) but probably involved a posttranscriptional or posttranslational modulation of this enzymatic activity. Taken together these findings provided further evidence of toxic effects on brain after C60 exposure. PMID:23865059

  12. Effect of thermal stress and water deprivation on the acetylcholinesterase activity of the pig brain and hypophyses

    NASA Astrophysics Data System (ADS)

    Adejumo, D. O.; Egbunike, G. N.

    1988-06-01

    The effects of direct exposure of boars to thermal stress for 1 h daily for 5 days and to acute water deprivation for 24 or 48 h were studied on the acetylcholinesterase (AChE) activity of porcine brain and hypophysial regions. Mean ambient temperatures, respiratory rates and rectal temperatures in the open were significantly higher than inside the pen. Heat stress induced a rise in AChE activities in the pons, cerebellum, amygdala, hippocampus, hypothalamus, mid-brain and medulla oblongata. However, no significant changes were observed in the cerebral cortex, adenohypophysis and neurohypophysis. Water deprivation significantly ( P<0.05) depressed AChE activity to varying extents depending on the duration of water restriction. Thus AChE activity in the amygdala was depressed by water deprivation for 24 h but partially restored at 48 h. The pons and medulla oblongata were comparable to the amygdala in this respect. The adenohypophysis and neurohypophysis were relatively unaffected.

  13. Anti-acetylcholinesterase and Antioxidant Activities of Inhaled Juniper Oil on Amyloid Beta (1-42)-Induced Oxidative Stress in the Rat Hippocampus.

    PubMed

    Cioanca, Oana; Hancianu, Monica; Mihasan, Marius; Hritcu, Lucian

    2015-05-01

    Juniper volatile oil is extracted from Juniperus communis L., of the Cupressaceae family, also known as common juniper. Also, in aromatherapy the juniper volatile oil is used against anxiety, nervous tension and stress-related conditions. In the present study, we identified the effects of the juniper volatile oil on amyloid beta (1-42)-induced oxidative stress in the rat hippocampus. Rats received a single intracerebroventricular injection of amyloid beta (1-42) (400 pmol/rat) and then were exposed to juniper volatile oil (200 μl, either 1 or 3 %) for controlled 60 min period, daily, for 21 continuous days. Also, the antioxidant activity in the hippocampus was assessed using superoxide dismutase, glutathione peroxidase and catalase specific activities, the total content of the reduced glutathione, protein carbonyl and malondialdehyde levels. Additionally, the acetylcholinesterase activity in the hippocampus was assessed. The amyloid beta (1-42)-treated rats exhibited the following: increase of the acetylcholinesterase, superoxide dismutase and catalase specific activities, decrease of glutathione peroxidase specific activity and the total content of the reduced glutathione along with an elevation of malondialdehyde and protein carbonyl levels. Inhalation of the juniper volatile oil significantly decreases the acetylcholinesterase activity and exhibited antioxidant potential. These findings suggest that the juniper volatile oil may be a potential candidate for the development of therapeutic agents to manage oxidative stress associated with Alzheimer's disease through decreasing the activity of acetylcholinesterase and anti-oxidative mechanism. PMID:25743585

  14. Behavioral swimming effects and acetylcholinesterase activity changes in Jenynsia multidentata exposed to chlorpyrifos and cypermethrin individually and in mixtures.

    PubMed

    Bonansea, Rocío Inés; Wunderlin, Daniel Alberto; Amé, María Valeria

    2016-07-01

    The pesticides cypermethrin (CYP) and chlorpyrifos (CPF) were found together in water bodies located in agricultural and urban areas. However, the impact to non-target biota from exposure to mixtures has received little attention. In the current study, we evaluated changes in swimming behavior and cholinesterase enzymes activity in Jenynsia multidentata, to investigate the possible effects of these insecticides individually and in mixtures. Moreover, differences between technical and commercial mixtures of the pesticides were evaluated. Females of J. multidentata were exposed over 96-h to CYP (0.04 and 0.4µgL(-1)), CPF (0.4 and 4µgL(-1)), individually and in a technical and commercial mixtures. Swimming behavior was recorded after 24h and 96h of exposure. Also, we measured cholinesterase enzymes activity in brain and muscle after 96h of exposure. Exposure to CYP increased the exploratory activity of J. multidentata in the upper area of the aquarium. Fish exposed to CPF (4µg L(-1)) showed a decrease in swimming activity and an increase in the time spent at the bottom of the aquarium. Interestingly, fish exposed to the technical and commercial mixture of CYP and CPF displayed a different behavior based on the concentration of exposure. Low concentration of pesticides elicited an increase in J. multidentata swimming activity with preference for the upper area of the aquarium, and high concentrations caused decrease in swimming activity with preference for the bottom area of the aquarium. Based on the response of cholinesterase enzymes, acetylcholinesterase in muscle was more sensitive to exposure to CYP, CPF and their mixtures than in brain. A decrease in swimming behavior correlates significantly with the inhibition of acetylcholinesterase activity in muscle of J. multidentata exposed to high concentrations of pesticides. These results draw attention to the need of more studies on the potential ecotoxicological impact of pesticides and its mixtures at

  15. An Expedient Synthesis, Acetylcholinesterase Inhibitory Activity, and Molecular Modeling Study of Highly Functionalized Hexahydro-1,6-naphthyridines

    PubMed Central

    Almansour, Abdulrahman I.; Suresh Kumar, Raju; Arumugam, Natarajan; Basiri, Alireza; Kia, Yalda; Ashraf Ali, Mohamed

    2015-01-01

    A series of hexahydro-1,6-naphthyridines were synthesized in good yields by the reaction of 3,5-bis[(E)-arylmethylidene]tetrahydro-4(1H)-pyridinones with cyanoacetamide in the presence of sodium ethoxide under simple mixing at ambient temperature for 6–10 minutes and were assayed for their acetylcholinesterase (AChE) inhibitory activity using colorimetric Ellman's method. Compound 4e with methoxy substituent at ortho-position of the phenyl rings displayed the maximum inhibitory activity with IC50 value of 2.12 μM. Molecular modeling simulation of 4e was performed using three-dimensional structure of Torpedo californica AChE (TcAChE) enzyme to disclose binding interaction and orientation of this molecule into the active site gorge of the receptor. PMID:25710037

  16. Combined approach to demonstrate acetylcholinesterase activity changes in the rat brain following tabun intoxication and its treatment.

    PubMed

    Bajgar, Jiri; Hajek, Petr; Kassa, Jiri; Slizova, Dasa; Krs, Otakar; Karasova, Jana Zdarova; Fusek, Josef; Capek, Lukas; Voicu, Victor A

    2012-01-01

    Reactivation effects of K203 and currently available oximes (obidoxime, HI-6) in combination with atropine on acetylcholinesterase activities in the brain parts of rats poisoned with tabun were studied. The activity was determined by quantitative histochemical and biochemical methods correlating between them very well. The tabun-induced changes in acetylcholinsterase activity as well as in reactivation potency of reactivators used were different in various parts of the brain. Pontomedullar area seems to be important for observed changes following tabun intoxication and its treatment. From the oximes studied, the reactivation effect of K203 was comparable with obidoxime; HI-6 was ineffective. Combination of bio- and histochemical methods allow fine differentiation among the action of different oximes following tabun poisoning. PMID:21851296

  17. Structure-Activity Relations In Enzymes: An Application Of IR-ATR Modulation Spectroscopy

    NASA Astrophysics Data System (ADS)

    Fringeli, Urs P.; Ahlstrom, Peter; Vincenz, Claudius; Fringeli, Marianna

    1985-12-01

    Relations between structure and specific activity in immobilized acetylcholinesterase (ACNE) have been studied by means of pH- and Ca++-modulation technique combined with attenuated total reflection (ATR) infrared (IR) spectroscopy and enzyme activity measurement. Periodic modulation of pH and Ca++-concentration enabled a periodic on-off switching of about 40% of the total enzyme activity. It was found that about 0.5 to 1% of the amino acids were involved in this process. These 15 to 30 amino acids assumed antiparallel pleated sheet structure in the inhibited state and random and/or helical structure in the activated state.

  18. Inhibition and Larvicidal Activity of Phenylpropanoids from Piper sarmentosum on Acetylcholinesterase against Mosquito Vectors and Their Binding Mode of Interaction

    PubMed Central

    Hematpoor, Arshia; Liew, Sook Yee; Chong, Wei Lim; Azirun, Mohd Sofian; Lee, Vannajan Sanghiran; Awang, Khalijah

    2016-01-01

    Aedes aegypti, Aedes albopictus and Culex quinquefasciatus are vectors of dengue fever and West Nile virus diseases. This study was conducted to determine the toxicity, mechanism of action and the binding interaction of three active phenylpropanoids from Piper sarmentosum (Piperaceae) toward late 3rd or early 4th larvae of above vectors. A bioassay guided-fractionation on the hexane extract from the roots of Piper sarmentosum led to the isolation and identification of three active phenylpropanoids; asaricin 1, isoasarone 2 and trans-asarone 3. The current study involved evaluation of the toxicity and acetylcholinesterase (AChE) inhibition of these compounds against Aedes aegypti, Aedes albopictus and Culex quinquefasciatus larvae. Asaricin 1 and isoasarone 2 were highly potent against Aedes aegypti, Aedes albopictus and Culex quinquefasciatus larvae causing up to 100% mortality at ≤ 15 μg/mL concentration. The ovicidal activity of asaricin 1, isoasarone 2 and trans-asarone 3 were evaluated through egg hatching. Asaricin 1 and isoasarone 2 showed potent ovicidal activity. Ovicidal activity for both compounds was up to 95% at 25μg/mL. Asaricin 1 and isoasarone 2 showed strong inhibition on acetylcholinesterase with relative IC50 values of 0.73 to 1.87 μg/mL respectively. These findings coupled with the high AChE inhibition may suggest that asaricin 1 and isoasarone 2 are neuron toxic compounds toward Aedes aegypti, Aedes albopictus and Culex quinquefasciatus. Further computational docking with Autodock Vina elaborates the possible interaction of asaricin 1 and isoasarone 2 with three possible binding sites of AChE which includes catalytic triads (CAS: S238, E367, H480), the peripheral sites (PAS: E72, W271) and anionic binding site (W83). The binding affinity of asaricin 1 and isoasarone 2 were relatively strong with asaricin 1 showed a higher binding affinity in the anionic pocket. PMID:27152416

  19. Inhibition and Larvicidal Activity of Phenylpropanoids from Piper sarmentosum on Acetylcholinesterase against Mosquito Vectors and Their Binding Mode of Interaction.

    PubMed

    Hematpoor, Arshia; Liew, Sook Yee; Chong, Wei Lim; Azirun, Mohd Sofian; Lee, Vannajan Sanghiran; Awang, Khalijah

    2016-01-01

    Aedes aegypti, Aedes albopictus and Culex quinquefasciatus are vectors of dengue fever and West Nile virus diseases. This study was conducted to determine the toxicity, mechanism of action and the binding interaction of three active phenylpropanoids from Piper sarmentosum (Piperaceae) toward late 3rd or early 4th larvae of above vectors. A bioassay guided-fractionation on the hexane extract from the roots of Piper sarmentosum led to the isolation and identification of three active phenylpropanoids; asaricin 1, isoasarone 2 and trans-asarone 3. The current study involved evaluation of the toxicity and acetylcholinesterase (AChE) inhibition of these compounds against Aedes aegypti, Aedes albopictus and Culex quinquefasciatus larvae. Asaricin 1 and isoasarone 2 were highly potent against Aedes aegypti, Aedes albopictus and Culex quinquefasciatus larvae causing up to 100% mortality at ≤ 15 μg/mL concentration. The ovicidal activity of asaricin 1, isoasarone 2 and trans-asarone 3 were evaluated through egg hatching. Asaricin 1 and isoasarone 2 showed potent ovicidal activity. Ovicidal activity for both compounds was up to 95% at 25μg/mL. Asaricin 1 and isoasarone 2 showed strong inhibition on acetylcholinesterase with relative IC50 values of 0.73 to 1.87 μg/mL respectively. These findings coupled with the high AChE inhibition may suggest that asaricin 1 and isoasarone 2 are neuron toxic compounds toward Aedes aegypti, Aedes albopictus and Culex quinquefasciatus. Further computational docking with Autodock Vina elaborates the possible interaction of asaricin 1 and isoasarone 2 with three possible binding sites of AChE which includes catalytic triads (CAS: S238, E367, H480), the peripheral sites (PAS: E72, W271) and anionic binding site (W83). The binding affinity of asaricin 1 and isoasarone 2 were relatively strong with asaricin 1 showed a higher binding affinity in the anionic pocket. PMID:27152416

  20. Synthesis and evaluation of novel 1,2,3-triazole-based acetylcholinesterase inhibitors with neuroprotective activity.

    PubMed

    Li, Jia-Cheng; Zhang, Juan; Rodrigues, Mosar Corrêa; Ding, De-Jun; Longo, João Paulo Figueiró; Azevedo, Ricardo Bentes; Muehlmann, Luis Alexandre; Jiang, Cheng-Shi

    2016-08-15

    A series of new 1,2,3-triazole derivatives were synthesized and evaluated for anticholinesterase and neuroprotective activities. Some synthetic derivatives, especially compound 32, exhibited improved acetylcholinesterase (AChE) inhibitory activity by comparison with the hit 1, high selectivity toward AChE over butyrylcholinesterase (BuChE), and suitable in vitro neuroprotective effect against amyloid-β25-35 (Aβ25-35)-induced neurotoxicity in SH-SY5Y cells. Furthermore, these molecules have desired physicochemical properties in the range of CNS drugs and showed no cytotoxicity against two normal cells, including human keratinocytes HaCaT and murine fibroblasts NIH-3T3. The preliminary bioassay results and docking study indicated that compound 32 might be a promising lead compound with dual action for the treatment of Alzheimer's disease. PMID:27426301

  1. [Distribution of acetylcholinesterase activity in the digestive system of the gastropod molluscs Littorina littorea and Achatina fulica].

    PubMed

    Zaĭtseva, O V; Kuznetsova, T V

    2008-01-01

    With the use of the histochemical procedure for the demonstration of acetylcholinesterase (AchE) activity, the distribution cholinergic regulatory elements was studied in the esophagus, the pharynx, the stomach, the liver (the digestive gland) and the intestine in sea and terrestrial gastropod molluscs that differed in their general organization level, lifestyle, habitat and feeding type. In both molluscs, all the parts of the digestive tract contained the significant amount of intraepithelial AchE-positive cells of the open type, single subepithelial neurons and the nervous fibers localized among the muscle cells of the wall of the organs. The basal processes of the AchE-positive intraepithelial cells were shown to form the intraepithelial nerve plexus and to pass under the epithelium. The peculiarities and common principles in the distribution of the nervous elements detected, their possible function and the regulatory role in the digestion in gastropod molluscs and other animals are discussed. PMID:19069417

  2. Zebrafish locomotor capacity and brain acetylcholinesterase activity is altered by Aphanizomenon flos-aquae DC-1 aphantoxins.

    PubMed

    Zhang, De Lu; Hu, Chun Xiang; Li, Dun Hai; Liu, Yong Ding

    2013-08-15

    Aphanizomenon flos-aquae (A. flos-aquae) is a source of neurotoxins known as aphantoxins or paralytic shellfish poisons (PSPs) that present a major threat to the environment and to human health. Generally, altered neurological function is reflected in behavior. Although the molecular mechanism of action of PSPs is well known, its neurobehavioral effects on adult zebrafish and its relationship with altered neurological functions are poorly understood. Aphantoxins purified from a natural isolate of A. flos-aquae DC-1 were analyzed by HPLC. The major analogs found in the toxins were the gonyautoxins 1 and 5 (GTX1 and GTX5; 34.04% and 21.28%, respectively) and the neosaxitoxin (neoSTX, 12.77%). Zebrafish (Danio rerio) were intraperitoneally injected with 5.3 and 7.61 μg STXeq/kg (low and high dose, respectively) of A. flos-aquae DC-1 aphantoxins. The swimming activity was investigated by observation combined with video at 6 timepoints from 1 to 24 h post-exposure. Both aphantoxin doses were associated with delayed touch responses, reduced head-tail locomotory abilities, inflexible turning of head, and a tailward-shifted center of gravity. The normal S-pattern (or undulating) locomotor trajectory was replaced by a mechanical motor pattern of swinging the head after wagging the tail. Finally, these fish principally distributed at the top and/or bottom water of the aquarium, and showed a clear polarized distribution pattern at 12 h post-exposure. Further analysis of neurological function demonstrated that both aphantoxin doses inhibited brain acetylcholinesterase activity. All these changes were dose- and time-dependent. These results demonstrate that aphantoxins can alter locomotor capacity, touch responses and distribution patterns by damaging the cholinergic system of zebrafish, and suggest that zebrafish locomotor behavior and acetylcholinesterase can be used as indicators for investigating aphantoxins and blooms in nature. PMID:23792258

  3. Acetylcholinesterase: From 3D Structure to Function

    PubMed Central

    Dvir, Hay; Silman, Israel; Harel, Michal; Rosenberry, Terrone L.; Sussman, Joel L.

    2010-01-01

    By rapid hydrolysis of the neurotransmitter, acetylcholine, acetylcholinesterase terminates neurotransmission at cholinergic synapses. Acetylcholinesterase is a very fast enzyme, functioning at a rate approaching that of a diffusion-controlled reaction. The powerful toxicity of organophosphate poisons is attributed primarily to their potent inhibition of acetylcholinesterase. Acetylcholinesterase inhibitors are utilized in the treatment of various neurological disorders, and are the principal drugs approved thus far by the FDA for management of Alzheimer’s disease. Many organophosphates and carbamates serve as potent insecticides, by selectively inhibiting insect acetylcholinesterase. The determination of the crystal structure of Torpedo californica acetylcholinesterase permitted visualization, for the first time, at atomic resolution, of a binding pocket for acetylcholine. It also allowed identification of the active site of acetylcholinesterase, which, unexpectedly, is located at the bottom of a deep gorge lined largely by aromatic residues. The crystal structure of recombinant human acetylcholinesterase in its apo-state is similar in its overall features to that of the Torpedo enzyme; however, the unique crystal packing reveals a novel peptide sequence which blocks access to the active-site gorge. PMID:20138030

  4. Acetylcholinesterase immobilization and characterization, and comparison of the activity of the porous silicon-immobilized enzyme with its free counterpart.

    PubMed

    Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

    2016-01-01

    A successful prescription is presented for acetylcholinesterase physically adsorbed on to a mesoporous silicon surface, with a promising hydrolytic response towards acetylthiocholine iodide. The catalytic behaviour of the immobilized enzyme was assessed by spectrophotometric bioassay using neostigmine methyl sulfate as a standard acetycholinesterase inhibitor. The surface modification was studied through field emission SEM, Fourier transform IR spectroscopy, energy-dispersive X-ray spectroscopy, cathode luminescence and X-ray photoelectron spectroscopy analysis, photoluminescence measurement and spectrophotometric bioassay. The porous silicon-immobilized enzyme not only yielded greater enzyme stability, but also significantly improved the native photoluminescence at room temperature of the bare porous silicon architecture. The results indicated the promising catalytic behaviour of immobilized enzyme compared with that of its free counterpart, with a greater stability, and that it aided reusability and easy separation from the reaction mixture. The porous silicon-immobilized enzyme was found to retain 50% of its activity, promising thermal stability up to 90°C, reusability for up to three cycles, pH stability over a broad pH of 4-9 and a shelf-life of 44 days, with an optimal hydrolytic response towards acetylthiocholine iodide at variable drug concentrations. On the basis of these findings, it was believed that the porous silicon-immobilized enzyme could be exploited as a reusable biocatalyst and for screening of acetylcholinesterase inhibitors from crude plant extracts and synthesized organic compounds. Moreover, the immobilized enzyme could offer a great deal as a viable biocatalyst in bioprocessing for the chemical and pharmaceutical industries, and bioremediation to enhance productivity and robustness. PMID:26839417

  5. Acetylcholinesterase immobilization and characterization, and comparison of the activity of the porous silicon-immobilized enzyme with its free counterpart

    PubMed Central

    Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

    2016-01-01

    A successful prescription is presented for acetylcholinesterase physically adsorbed on to a mesoporous silicon surface, with a promising hydrolytic response towards acetylthiocholine iodide. The catalytic behaviour of the immobilized enzyme was assessed by spectrophotometric bioassay using neostigmine methyl sulfate as a standard acetycholinesterase inhibitor. The surface modification was studied through field emission SEM, Fourier transform IR spectroscopy, energy-dispersive X-ray spectroscopy, cathode luminescence and X-ray photoelectron spectroscopy analysis, photoluminescence measurement and spectrophotometric bioassay. The porous silicon-immobilized enzyme not only yielded greater enzyme stability, but also significantly improved the native photoluminescence at room temperature of the bare porous silicon architecture. The results indicated the promising catalytic behaviour of immobilized enzyme compared with that of its free counterpart, with a greater stability, and that it aided reusability and easy separation from the reaction mixture. The porous silicon-immobilized enzyme was found to retain 50% of its activity, promising thermal stability up to 90°C, reusability for up to three cycles, pH stability over a broad pH of 4–9 and a shelf-life of 44 days, with an optimal hydrolytic response towards acetylthiocholine iodide at variable drug concentrations. On the basis of these findings, it was believed that the porous silicon-immobilized enzyme could be exploited as a reusable biocatalyst and for screening of acetylcholinesterase inhibitors from crude plant extracts and synthesized organic compounds. Moreover, the immobilized enzyme could offer a great deal as a viable biocatalyst in bioprocessing for the chemical and pharmaceutical industries, and bioremediation to enhance productivity and robustness. PMID:26839417

  6. Aqueous Extracts from Tunisian Diplotaxis: Phenol Content, Antioxidant and Anti-Acetylcholinesterase Activities, and Impact of Exposure to Simulated Gastrointestinal Fluids.

    PubMed

    Bahloul, Nada; Bellili, Sana; Aazza, Smail; Chérif, Ameur; Faleiro, Maria Leonor; Antunes, Maria Dulce; Miguel, Maria Graça; Mnif, Wissem

    2016-01-01

    Antioxidants have been considered essential for preventing cell damage by scavenging deleterious free radicals. The consumption of antioxidant-rich plants is associated with a reduced risk of some chronic diseases. This study evaluates the antioxidant and acetylcholinesterase inhibition activities of aqueous extracts obtained from different parts of Diplotaxis simplex and Diplotaxis harra from Tunisia. The study also aimed to investigate the action of simulated gastrointestinal juice on antioxidant activities of both extracts. The total phenolic, flavone and flavonol, and flavanone and dihydroflavonol contents were determined by Folin-Ciocalteau, aluminum chloride and 2,4-dinitrophenylhydrazine colorimetric methods, respectively. The metal ion chelating activity, acetylcholinesterase inhibition capacity, and free radical scavenging potential of the extracts towards ABTS (2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid), DPPH (2,2-diphenyl-1-picrylhydrazyl), hydroxyl, superoxide and nitric oxide were also evaluated. The action of simulated gastro-intestinal fluids on the flavone and flavonol content and total antioxidant activity of the flower extracts was surveyed. Extracts from the seeds and flowers of D. simplex and D. harra displayed the highest amounts of phenols (2691.7 and 2694.5 mg Caffeic Acid Equivalent (CAE)/100 mg; 3433.4 and 2647.2 mg CAE/100 mg, respectively) and flavonols/flavones (2144.4 and 2061.1 mg Rutin Equivalent (RE)/100 g; 1922.6 and 1461.1 mg RE/100 g, respectively). The flower and seed extracts exhibited the highest rates of antioxidant and acetylcholinesterase inhibition activities. A decrease in the flavonoid content and antioxidant activity was observed after extract exposure to simulated saliva. Antioxidant and acetylcholinesterase inhibition activities were noted to depend on plant species and plant parts. In vitro gastrointestinal digestion is useful in assessing the bio-accessibility of compounds with biological activities from

  7. Aqueous Extracts from Tunisian Diplotaxis: Phenol Content, Antioxidant and Anti-Acetylcholinesterase Activities, and Impact of Exposure to Simulated Gastrointestinal Fluids

    PubMed Central

    Bahloul, Nada; Bellili, Sana; Aazza, Smail; Chérif, Ameur; Faleiro, Maria Leonor; Antunes, Maria Dulce; Miguel, Maria Graça; Mnif, Wissem

    2016-01-01

    Antioxidants have been considered essential for preventing cell damage by scavenging deleterious free radicals. The consumption of antioxidant-rich plants is associated with a reduced risk of some chronic diseases. This study evaluates the antioxidant and acetylcholinesterase inhibition activities of aqueous extracts obtained from different parts of Diplotaxis simplex and Diplotaxis harra from Tunisia. The study also aimed to investigate the action of simulated gastrointestinal juice on antioxidant activities of both extracts. The total phenolic, flavone and flavonol, and flavanone and dihydroflavonol contents were determined by Folin–Ciocalteau, aluminum chloride and 2,4-dinitrophenylhydrazine colorimetric methods, respectively. The metal ion chelating activity, acetylcholinesterase inhibition capacity, and free radical scavenging potential of the extracts towards ABTS (2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid), DPPH (2,2-diphenyl-1-picrylhydrazyl), hydroxyl, superoxide and nitric oxide were also evaluated. The action of simulated gastro-intestinal fluids on the flavone and flavonol content and total antioxidant activity of the flower extracts was surveyed. Extracts from the seeds and flowers of D. simplex and D. harra displayed the highest amounts of phenols (2691.7 and 2694.5 mg Caffeic Acid Equivalent (CAE)/100 mg; 3433.4 and 2647.2 mg CAE/100 mg, respectively) and flavonols/flavones (2144.4 and 2061.1 mg Rutin Equivalent (RE)/100 g; 1922.6 and 1461.1 mg RE/100 g, respectively). The flower and seed extracts exhibited the highest rates of antioxidant and acetylcholinesterase inhibition activities. A decrease in the flavonoid content and antioxidant activity was observed after extract exposure to simulated saliva. Antioxidant and acetylcholinesterase inhibition activities were noted to depend on plant species and plant parts. In vitro gastrointestinal digestion is useful in assessing the bio-accessibility of compounds with biological activities

  8. An attempt to assess functionally minimal acetylcholinesterase activity necessary for survival of rats intoxicated with nerve agents.

    PubMed

    Bajgar, Jiri; Fusek, Josef; Kassa, Jiri; Jun, Daniel; Kuca, Kamil; Hajek, Petr

    2008-09-25

    Acetylcholinesterase (AChE, EC 3.1.1.7) is an important enzyme for cholinergic nerve transmission. The action of toxic organophosphates such as nerve agents is based on AChE inhibition. The death following acute nerve agent poisoning is due to central or peripheral respiratory/cardiac failure. Therefore, the changes in AChE activity following nerve agents acting predominantly on the central (sarin, soman) or peripheral (VX) level were studied. It is known that AChE activity in different structures exists in relative excess. Female Wistar rats intoxicated with sarin, soman, and VX in different doses (0.5-2.0 x LD(50)) were divided into groups of survived and died animals. AChE activities in diaphragm, brain parts (pontomedullar area, frontal cortex, basal ganglia, in some cases other parts of the brain) were determined and the rest of activity (in %) was correlated with survival/death of animals. More precise elucidation of action of nerve agents and the assessment of minimal AChE activity in different organs compatible with the survival of organism poisoned with nerve agents were the aims of this study. PMID:18579126

  9. Highly sensitive electrochemiluminescenc assay of acetylcholinesterase activity based on dual biomarkers using Pd-Au nanowires as immobilization platform.

    PubMed

    Ye, Cui; Wang, Min-Qiang; Zhong, Xia; Chen, Shihong; Chai, Yaqin; Yuan, Ruo

    2016-05-15

    One-dimensional Pd-Au nanowires (Pd-Au NWs) were prepared and applied to fabricate an electrochemiluminescence (ECL) biosensor for the detection of acetylcholinesterase (AChE) activity. Compared with single-component of Pd or Au, the bimetallic nanocomposite of Pd-Au NWs offers a larger surface area for the immobilization of enzyme, and displays superior electrocatalytic activity and efficient electron transport capacity. In the presence of AChE and choline oxidase (ChOx), acetylcholine (ATCl) is hydrolyzed by AChE to generate thiocholine, then thiocholine is catalyzed by ChOx to produce H2O2 in situ, which serves as the coreactant to effectively enhance the ECL intensity in luminol-ECL system. The detection principle is based on the inhibited AChE and reactivated AChE as dual biomarkers, in which AChE was inhibited by organophosphorus (OP) agents, and then reactivated by obidoxime. Such dual biomarkers method can achieve credible evaluation for AChE activity via providing AChE activity before and after reactivation. The liner range for AChE activity detection was from 0.025 U L(-1) to 25 KU L(-1) with a low detection limit down to 0.0083 U L(-1). PMID:26686921

  10. Shift in aggregation, ROS generation, antioxidative defense, lysozyme and acetylcholinesterase activities in the cells of an Indian freshwater sponge exposed to washing soda (sodium carbonate).

    PubMed

    Mukherjee, Soumalya; Ray, Mitali; Ray, Sajal

    2016-09-01

    Washing soda, chemically identified as anhydrous sodium carbonate, is a popular cleaning agent among the rural and urban populations of India which often contaminates the freshwater ponds and lakes, the natural habitat of sponge Eunapius carteri. Present investigation deals with estimation of cellular aggregation, generation of ROS and activities of antioxidant enzymes, lysozyme and acetylcholinesterase in the cells of E. carteri under the environmentally realistic concentrations of washing soda. Prolonged treatment of washing soda inhibited the degree of cellular aggregation. Experimental exposure of 8 and 16mg/l of sodium carbonate for 48h elevated the physiological level of reactive oxygen species (ROS) generation in the agranulocytes, semigranulocytes and granulocytes of E. carteri, whereas, treatment of 192h inhibited the ROS generation in three cellular morphotypes. Activities of superoxide dismutase, catalase and glutathione-S-transferase were recorded to be inhibited under prolonged exposure of washing soda. Washing soda mediated inhibition of ROS generation and depletion in the activities of antioxidant enzymes were indicative to an undesirable shift in cytotoxic status and antioxidative defense in E. carteri. Inhibition in the activity of lysozyme under the treatment of sodium carbonate was suggestive to a severe impairment of the innate immunological efficiency of E. carteri distributed in the washing soda contaminated habitat. Washing soda mediated inhibition in the activity of acetylcholinesterase indicated its neurotoxicity in E. carteri. Washing soda, a reported environmental contaminant, affected adversely the immunophysiological status of E. carteri with reference to cellular aggregation, oxidative stress, antioxidative defense, lysozyme and acetylcholinesterase activity. PMID:27178357

  11. Acetylcholinesterase liquid crystal biosensor based on modulated growth of gold nanoparticles for amplified detection of acetylcholine and inhibitor.

    PubMed

    Liao, Shuzhen; Qiao, Yanan; Han, Wenting; Xie, Zhaoxia; Wu, Zhaoyang; Shen, Guoli; Yu, Ruqin

    2012-01-01

    A novel acetylcholinesterase (AChE) liquid crystal (LC) biosensor based on enzymatic growth of gold nanoparticles (Au NPs) has been developed for amplified detection of acetylcholine (ACh) and AChE inhibitor. In this method, AChE mediates the hydrolysis of acetylthiocholine (ATCl) to form thiocholine, and the latter further reduces AuCl(4)(-) to Au NPs without Au nanoseeds. This process, termed biometallization, leads to a great enhancement in the optical signal of the LC biosensor due to the large size of Au NPs, which can greatly disrupt the orientational arrangement of LCs. On the other hand, the hydrolysis of ATCl is inhibited in the presence of ACh or organophosphate pesticides (OPs, a AChE inhibitor), which will decrease the catalytic growth of Au NPs and, as a result, reduce the orientational response of LCs. On the basis of such an inhibition mechanism, the AChE LC biosensor can be used as an effective way to realize the detection of ACh and AChE inhibitors. The results showed that the AChE LC biosensor was highly sensitive to ACh with a detection limit of 15 μmol/L and OPs with a detection limit of 0.3 nmol/L. This study provides a simple and sensitive AChE LC biosensing approach and offers effective signal enhanced strategies for the development of enzyme LC biosensors. PMID:22148672

  12. Proline-induced changes in acetylcholinesterase activity and gene expression in zebrafish brain: reversal by antipsychotic drugs.

    PubMed

    Savio, L E B; Vuaden, F C; Kist, L W; Pereira, T C; Rosemberg, D B; Bogo, M R; Bonan, C D; Wyse, A T S

    2013-10-10

    Hyperprolinemia is an inherited disorder of proline metabolism and hyperprolinemic patients can present neurological manifestations, such as seizures, cognitive dysfunctions, and schizoaffective disorders. However, the mechanisms related to these symptoms are still unclear. In the present study, we evaluated the in vivo and in vitro effects of proline on acetylcholinesterase (AChE) activity and gene expression in the zebrafish brain. For the in vivo studies, animals were exposed at two proline concentrations (1.5 and 3.0mM) during 1h or 7 days (short- or long-term treatments, respectively). For the in vitro assays, different proline concentrations (ranging from 3.0 to 1000 μM) were tested. Long-term proline exposures significantly increased AChE activity for both treated groups when compared to the control (34% and 39%). Moreover, the proline-induced increase on AChE activity was completely reverted by acute administration of antipsychotic drugs (haloperidol and sulpiride), as well as the changes induced in ache expression. When assessed in vitro, proline did not promote significant changes in AChE activity. Altogether, these data indicate that the enzyme responsible for the control of acetylcholine levels might be altered after proline exposure in the adult zebrafish. These findings contribute for better understanding of the pathophysiology of hyperprolinemia and might reinforce the use of the zebrafish as a complementary vertebrate model for studying inborn errors of amino acid metabolism. PMID:23867765

  13. Rosmarinus officinalis L. leaf extract improves memory impairment and affects acetylcholinesterase and butyrylcholinesterase activities in rat brain.

    PubMed

    Ozarowski, Marcin; Mikolajczak, Przemyslaw L; Bogacz, Anna; Gryszczynska, Agnieszka; Kujawska, Malgorzata; Jodynis-Liebert, Jadwiga; Piasecka, Anna; Napieczynska, Hanna; Szulc, Michał; Kujawski, Radoslaw; Bartkowiak-Wieczorek, Joanna; Cichocka, Joanna; Bobkiewicz-Kozlowska, Teresa; Czerny, Boguslaw; Mrozikiewicz, Przemyslaw M

    2013-12-01

    Rosmarinus officinalis L. leaf as part of a diet and medication can be a valuable proposal for the prevention and treatment of dementia. The aim of the study was to assess the effects of subchronic (28-fold) administration of a plant extract (RE) (200 mg/kg, p.o.) on behavioral and cognitive responses of rats linked with acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activity and their mRNA expression level in the hippocampus and frontal cortex. The passive avoidance test results showed that RE improved long-term memory in scopolamine-induced rats. The extract inhibited the AChE activity and showed a stimulatory effect on BuChE in both parts of rat brain. Moreover, RE produced a lower mRNA BuChE expression in the cortex and simultaneously an increase in the hippocampus. The study suggests that RE led to improved long-term memory in rats, which can be partially explained by its inhibition of AChE activity in rat brain. PMID:24080468

  14. Effect of adult onset hypothyroidism on behavioral parameters and acetylcholinesterase isoforms activity in specific brain regions of male mice.

    PubMed

    Vasilopoulou, Catherine G; Constantinou, Caterina; Giannakopoulou, Dimitra; Giompres, Panagiotis; Margarity, Marigoula

    2016-10-01

    Thyroid hormones (TH) are essential for normal development and function of mammalian central nervous system (CNS); TH dysregulation has been implicated in several cognitive and behavioral deficits related to dysfunctions of neurotransmitter systems. In the present study, we investigated the effects of adult onset hypothyroidism on the activity of acetylcholinesterase (AChE) and on related behavioral parameters. For this purpose we used adult male Balb/cJ mice that were divided randomly into euthyroid and hypothyroid animal groups. Animals were rendered hypothyroid through administration of 1% w/v KClO4 in their drinking water for 8weeks. At the end of the treatment, learning/memory procedures were examined through step-through passive avoidance task while fear/anxiety was assessed using elevated plus-maze (EPM) and open-field (OF) tests. AChE activity was determined colorimetrically in two different fractions, salt-soluble fraction (SS) (containing mainly the G1 isoform) and detergent-soluble fraction (DS) (containing mainly the G4 isoform) in cerebral cortex, cerebellum, midbrain, hippocampus and striatum. Our results indicate that adult onset hypothyroidism caused significant memory impairment and increased fear/anxiety. Moreover, the activity of both isoforms of AChE was reduced in all brain regions examined in a brain region- and isoform-specific manner. PMID:27317840

  15. Macroeconomic Activity Module - NEMS Documentation

    EIA Publications

    2014-01-01

    Documents the objectives, analytical approach, and development of the National Energy Modeling System (NEMS) Macroeconomic Activity Module (MAM) used to develop the Annual Energy Outlook for 2014 (AEO2014). The report catalogues and describes the module assumptions, computations, methodology, parameter estimation techniques, and mainframe source code

  16. Macroeconomic Activity Module - NEMS Documentation

    EIA Publications

    2016-01-01

    Documents the objectives, analytical approach, and development of the National Energy Modeling System (NEMS) Macroeconomic Activity Module (MAM) used to develop the Annual Energy Outlook for 2016 (AEO2016). The report catalogues and describes the module assumptions, computations, methodology, parameter estimation techniques, and mainframe source code

  17. Naringenin Mitigates Iron-Induced Anxiety-Like Behavioral Impairment, Mitochondrial Dysfunctions, Ectonucleotidases and Acetylcholinesterase Alteration Activities in Rat Hippocampus.

    PubMed

    Chtourou, Yassine; Slima, Ahlem Ben; Gdoura, Radhouane; Fetoui, Hamadi

    2015-08-01

    Studies demonstrated that the iron chelating antioxidant restores brain dysfunction induced by iron toxicity in animals. Earlier, we found that iron overload-induced cerebral cortex apoptosis correlated with oxidative stress could be protected by naringenin (NGEN). In this respect, the present study is focused on the mechanisms associated with the protective efficacy of NGEN, natural flavonoid compound abundant in the peels of citrus fruit, on iron induced impairment of the anxiogenic-like behaviour, purinergic and cholinergic dysfunctions with oxidative stress related disorders on mitochondrial function in the rat hippocampus. Results showed that administration of NGEN (50 mg/kg/day) by gavage significantly ameliorated anxiogenic-like behaviour impairment induced by the exposure to 50 mg of Fe-dextran/kg/day intraperitoneally for 28 days in rats, decreased iron-induced reactive oxygen species formation and restored the iron-induced decrease of the acetylcholinesterase expression level, mitochondrial membrane potential and mitochondrial complexes activities in the hippocampus of rats. Moreover, NGEN was able to restore the alteration on the activity and expression of ectonucleotidases such as adenosine triphosphate diphosphohydrolase and 5'-nucleotidase, enzymes which hydrolyze and therefore control extracellular ATP and adenosine concentrations in the synaptic cleft. These results may contribute to a better understanding of the neuroprotective role of NGEN, emphasizing the influence of including this flavonoid in the diet for human health, possibly preventing brain injury associated with iron overload. PMID:26050208

  18. Effects of chlorpyrifos ethyl on acetylcholinesterase activity in climbing perch cultured in rice fields in the Mekong Delta, Vietnam.

    PubMed

    Nguyen, Tam Thanh; Berg, Håkan; Nguyen, Hang Thi Thuy; Nguyen, Cong Van

    2015-07-01

    Climbing perch is commonly harvested in rice fields and associated wetlands in the Mekong Delta. Despite its importance in providing food and income to local households, there is little information how this fish species is affected by the high use of pesticides in rice farming. Organophosphate insecticides, such as chlorpyrifos ethyl, which are highly toxic to aquatic organisms, are commonly used in the Mekong Delta. This study shows that the brain acetylcholinesterase (AChE) activity in climbing perch fingerlings cultured in rice fields, was significantly inhibited by a single application of chlorpyrifos ethyl, at doses commonly applied by rice farmers (0.32-0.64 kg/ha). The water concentration of chlorpyrifos ethyl decreased below the detection level within 3 days, but the inhibition of brain AChE activity remained for more than 12 days. In addition, the chlorpyrifos ethyl treatments had a significant impact on the survival and growth rates of climbing perch fingerlings, which were proportional to the exposure levels. The results indicate that the high use of pesticides among rice farmers in the Mekong Delta could have a negative impact on aquatic organisms and fish yields, with implications for the aquatic biodiversity, local people's livelihoods and the aquaculture industry in the Mekong Delta. PMID:25828891

  19. The Nature of Activated Non-classical Hydrogen Bonds: A Case Study on Acetylcholinesterase-Ligand Complexes.

    PubMed

    Berg, Lotta; Mishra, Brijesh Kumar; Andersson, C David; Ekström, Fredrik; Linusson, Anna

    2016-02-18

    Molecular recognition events in biological systems are driven by non-covalent interactions between interacting species. Here, we have studied hydrogen bonds of the CH⋅⋅⋅Y type involving electron-deficient CH donors using dispersion-corrected density functional theory (DFT) calculations applied to acetylcholinesterase-ligand complexes. The strengths of CH⋅⋅⋅Y interactions activated by a proximal cation were considerably strong; comparable to or greater than those of classical hydrogen bonds. Significant differences in the energetic components compared to classical hydrogen bonds and non-activated CH⋅⋅⋅Y interactions were observed. Comparison between DFT and molecular mechanics calculations showed that common force fields could not reproduce the interaction energy values of the studied hydrogen bonds. The presented results highlight the importance of considering CH⋅⋅⋅Y interactions when analysing protein-ligand complexes, call for a review of current force fields, and opens up possibilities for the development of improved design tools for drug discovery. PMID:26751405

  20. Intracerebroventricular D-galactose administration impairs memory and alters activity and expression of acetylcholinesterase in the rat.

    PubMed

    Rodrigues, André Felipe; Biasibetti, Helena; Zanotto, Bruna Stela; Sanches, Eduardo Farias; Pierozan, Paula; Schmitz, Felipe; Parisi, Mariana Migliorini; Barbé-Tuana, Florencia; Netto, Carlos Alexandre; Wyse, Angela T S

    2016-05-01

    Tissue accumulation of galactose is a hallmark in classical galactosemia. Cognitive deficit is a symptom of this disease which is poorly understood. The aim of this study was to investigate the effects of intracerebroventricular administration of galactose on memory (inhibitory avoidance and novel object recognition tasks) of adult rats. We also investigated the effects of galactose on acetylcholinesterase (AChE) activity, immunocontent and gene expression in hippocampus and cerebral cortex. Wistar rats received a single injection of galactose (4mM) or saline (control). For behavioral parameters, galactose was injected 1h or 24h previously to the testing. For biochemical assessment, animals were decapitated 1h, 3h or 24h after galactose or saline injection; hippocampus and cerebral cortex were dissected. Results showed that galactose impairs the memory formation process in aversive memory (inhibitory avoidance task) and recognition memory (novel object recognition task) in rats. The activity of AChE was increased, whereas the gene expression of this enzyme was decreased in hippocampus, but not in cerebral cortex. These findings suggest that these changes in AChE may, at least in part, to lead to memory impairment caused by galactose. Taken together, our results can help understand the etiopathology of classical galactosemia. PMID:26948151

  1. The activity of detoxifying enzymes in the infective juveniles of Heterorhabditis bacteriophora strains: Purification and characterization of two acetylcholinesterases.

    PubMed

    Mohamed, Magda A; Mahdy, El-Sayed M E; Ghazy, Abd-El-Hady M; Ibrahim, Nihal M; El-Mezayen, Hatem A; Ghanem, Manal M E

    2016-02-01

    The infectivity and detoxifying enzyme activities including glutathione-S-transferase (GST), acetylcholinesterase (AChE) and carboxylesterase (CaE) are investigated in the infective juveniles (IJs) of six different strains of Heterorhabditis bacteriophora as a biocontrol agent against insect pests. The specific activities ranged from 10.8-29.8 and 50-220units/mg protein for GST and AChE, respectively; and from 24.7-129 and 22.6-77.3units/mg protein for CaE as estimated by P-nitrophenyl and α-naphthyl acetates, respectively. H. bacteriophora EM2 strain has the highest infectivity and the highest enzymatic activities as well. AChE is the predominant detoxifying enzyme that might imply its major role in the detoxification of insecticide(s). The isoenzyme pattern demonstrated two major slow-moving isoforms in all EPN strains examined. Purification of two AChE isoforms, AChEAII and AChEBI, from H. bacteriophora EM2 strain is performed by ammonium sulfate precipitation, gel filtration on Sephacryl S-200 and chromatography on DEAE-Sepharose. AChEAII and AChEBII have specific activities of 1207 and 1560unit/mg protein, native molecular weights of 180 and 68kDa, and are found in dimeric and monomeric forms, respectively. Both isoforms showed optimum activity at pH8.5 and 35°C. AChEBI exhibited higher thermal stability and higher activation energy than AChEAII. The enzymatic activities of purified AChEs are completely inhibited by Hg(+2) and Ni(+2) and greatly enhanced by Mn(+2). The substrate specificity, the relative efficiency of substrates hydrolysis, substrate inhibition and inhibition by BW284C51, but not by iso-OMPA, clearly indicated that they are true AChEs; their properties are compared with those recorded for insects as target hosts for H. bacteriophora EM2. PMID:26545490

  2. Local salt substitutes “Obu-otoyo” activate acetylcholinesterase and butyrylcholinesterase and induce lipid peroxidation in rat brain

    PubMed Central

    Oboh, Ganiyu; Ademiluyi, Adedayo O.

    2015-01-01

    Evidence has shown that ingestion of heavy metals can lead to neurodegenerative diseases. This study aimed to investigate the neurotoxic potential of salt substitutes (Obu-Otoyo); salt A (made by burning palm kernel shaft then soaked in water overnight and the extract from the resulting residue is used as the salt substitute) and salt B (an unrefined salt mined from a local site at Ilobu town, Osun-State, Nigeria) by assessing their effect on some key enzymes linked with neurodegenerative disease [acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities] as well as on malondialdehyde (MDA) content of the rat brain. Salt substitutes were fed to normal rats as dietary inclusion at doses of 0.5 and 1.0% for 30 days. Thereafter, the effect of the salt substitutes on AChE and BChE activities as well as on MDA level in the rat brain was determined. The results revealed that the salt substitutes caused a significant (p<0.05) increase in both AChE and BChE activity and also induced lipid peroxidation in the brain of rats in vivo as well as under in vitro condition in a dose-dependent manner. The effect of the salt substitutes on AChE and BChE activities could be attributed to the presence of some toxic heavy metals. Therefore, the ability of the salt substitutes to induce lipid peroxidation and activate AChE and BChE activities could provide some possible mechanism for their neurotoxic effect. PMID:27486373

  3. Silibinin inhibits acetylcholinesterase activity and amyloid β peptide aggregation: a dual-target drug for the treatment of Alzheimer's disease.

    PubMed

    Duan, Songwei; Guan, Xiaoyin; Lin, Runxuan; Liu, Xincheng; Yan, Ying; Lin, Ruibang; Zhang, Tianqi; Chen, Xueman; Huang, Jiaqi; Sun, Xicui; Li, Qingqing; Fang, Shaoliang; Xu, Jun; Yao, Zhibin; Gu, Huaiyu

    2015-05-01

    Alzheimer's disease (AD) is characterized by amyloid β (Aβ) peptide aggregation and cholinergic neurodegeneration. Therefore, in this paper, we examined silibinin, a flavonoid extracted from Silybum marianum, to determine its potential as a dual inhibitor of acetylcholinesterase (AChE) and Aβ peptide aggregation for AD treatment. To achieve this, we used molecular docking and molecular dynamics simulations to examine the affinity of silibinin with Aβ and AChE in silico. Next, we used circular dichroism and transmission electron microscopy to study the anti-Aβ aggregation capability of silibinin in vitro. Moreover, a Morris Water Maze test, enzyme-linked immunosorbent assay, immunohistochemistry, 5-bromo-2-deoxyuridine double labeling, and a gene gun experiment were performed on silibinin-treated APP/PS1 transgenic mice. In molecular dynamics simulations, silibinin interacted with Aβ and AChE to form different stable complexes. After the administration of silibinin, AChE activity and Aβ aggregations were down-regulated, and the quantity of AChE also decreased. In addition, silibinin-treated APP/PS1 transgenic mice had greater scores in the Morris Water Maze. Moreover, silibinin could increase the number of newly generated microglia, astrocytes, neurons, and neuronal precursor cells. Taken together, these data suggest that silibinin could act as a dual inhibitor of AChE and Aβ peptide aggregation, therefore suggesting a therapeutic strategy for AD treatment. PMID:25771396

  4. Acetylcholinesterase and insect growth inhibitory activities of Gutierrezia microcephala on fall armyworm Spodoptera frugiperda J.E. Smith.

    PubMed

    Calderón, J S; Céspedes, C L; Rosas, R; Gómez-Garibay, F; Salazar, J R; Lina, L; Aranda, E; Kubo, I

    2001-01-01

    From the aerial parts of Gutierrezia microcephala (Asteraceae), four oxyflavones were isolated, namely 5,7,2'-trihydroxy-3,6,8,4',5'-pentamethoxyflavone (1); 5,7,4'-trihydroxy-3,6,8-trimethoxyflavone (2); 5,7,2',4'-tetrahydroxy-3,6,8,5'-tetramethoxyflavone (3); 5,2'-dihydroxy-3,6,7,8,4',5'-hexamethoxyflavone (4), and an ent-clerodane, bacchabolivic acid (5). Compounds 1-5, the synthetic methyl ester (6), n-hexane and MeOH extracts were evaluated against the fall armyworm (Spodoptera frugiperda). Gedunin, a known insect growth regulator isolated from Cedrela spp. was used as a positive control. When tested for activity on neonate larvae into the no-choice artificial diet bioassay, flavone (1), clerodane (5), its methyl ester (6), MeOH and n-hexane extracts caused significant larval mortality with MC50 of 3.9, 10.7, 3.46, 7.95 and 7.5 ppm at 7 days, respectively, as well as growth reduction. They also increased the development time of surviving larvae and a significant delay in time to pupation and adult emergence. Acute toxicity against adults of S. frugiperda was also found, 5, 6, gedunin and n-hexane extract had the most potent activity with LD50 value of 6.59, 15.05, 10.78, and 12.79 ppm, respectively. In addition, MeOH, n-hexane extracts, 5, 6 and gedunin caused acetylcholinesterase inhibition with 93.7, 100, 90.2, 62.0 and 100% at 50.0 ppm, respectively; whereas 1-4 exhibited only moderate inhibitory activity. Compounds 1, 5 and 6 showed inhibitory activities comparable with gedunin. These compounds could be responsible of the insect growth inhibitory activity of this plant. PMID:11421454

  5. Acetylcholinesterase Inhibitors: Pharmacology and Toxicology

    PubMed Central

    Čolović, Mirjana B; Krstić, Danijela Z; Lazarević-Pašti, Tamara D; Bondžić, Aleksandra M; Vasić, Vesna M

    2013-01-01

    Acetylcholinesterase is involved in the termination of impulse transmission by rapid hydrolysis of the neurotransmitter acetylcholine in numerous cholinergic pathways in the central and peripheral nervous systems. The enzyme inactivation, induced by various inhibitors, leads to acetylcholine accumulation, hyperstimulation of nicotinic and muscarinic receptors, and disrupted neurotransmission. Hence, acetylcholinesterase inhibitors, interacting with the enzyme as their primary target, are applied as relevant drugs and toxins. This review presents an overview of toxicology and pharmacology of reversible and irreversible acetylcholinesterase inactivating compounds. In the case of reversible inhibitors being commonly applied in neurodegenerative disorders treatment, special attention is paid to currently approved drugs (donepezil, rivastigmine and galantamine) in the pharmacotherapy of Alzheimer’s disease, and toxic carbamates used as pesticides. Subsequently, mechanism of irreversible acetylcholinesterase inhibition induced by organophosphorus compounds (insecticides and nerve agents), and their specific and nonspecific toxic effects are described, as well as irreversible inhibitors having pharmacological implementation. In addition, the pharmacological treatment of intoxication caused by organophosphates is presented, with emphasis on oxime reactivators of the inhibited enzyme activity administering as causal drugs after the poisoning. Besides, organophosphorus and carbamate insecticides can be detoxified in mammals through enzymatic hydrolysis before they reach targets in the nervous system. Carboxylesterases most effectively decompose carbamates, whereas the most successful route of organophosphates detoxification is their degradation by corresponding phosphotriesterases. PMID:24179466

  6. In Vitro and In Vivo Metabolism and Inhibitory Activities of Vasicine, a Potent Acetylcholinesterase and Butyrylcholinesterase Inhibitor

    PubMed Central

    Liu, Wei; Shi, Xiaoyuan; Yang, Yadi; Cheng, Xuemei; Liu, Qing; Han, Han; Yang, Baohua; He, Chunyong; Wang, Yongli; Jiang, Bo; Wang, Zhengtao; Wang, Changhong

    2015-01-01

    Vasicine (VAS), a potential natural cholinesterase inhibitor, exhibited promising anticholinesterase activity in preclinical models and has been in development for treatment of Alzheimer’s disease. This study systematically investigated the in vitro and in vivo metabolism of VAS in rat using ultra performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight mass spectrometry. A total of 72 metabolites were found based on a detailed analysis of their 1H- NMR and 13C NMR data. Six key metabolites were isolated from rat urine and elucidated as vasicinone, vasicinol, vasicinolone, 1,2,3,9-tetrahydropyrrolo [2,1-b] quinazolin-3-yl hydrogen sulfate, 9-oxo-1,2,3,9-tetrahydropyrrolo [2,1-b] quinazolin-3-yl hydrogen sulfate, and 1,2,3,9-tetrahydropyrrolo [2,1-b] quinazolin-3-β-D-glucuronide. The metabolic pathway of VAS in vivo and in vitro mainly involved monohydroxylation, dihydroxylation, trihydroxylation, oxidation, desaturation, sulfation, and glucuronidation. The main metabolic soft spots in the chemical structure of VAS were the 3-hydroxyl group and the C-9 site. All 72 metabolites were found in the urine sample, and 15, 25, 45, 18, and 11 metabolites were identified from rat feces, plasma, bile, rat liver microsomes, and rat primary hepatocyte incubations, respectively. Results indicated that renal clearance was the major excretion pathway of VAS. The acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities of VAS and its main metabolites were also evaluated. The results indicated that although most metabolites maintained potential inhibitory activity against AChE and BChE, but weaker than that of VAS. VAS undergoes metabolic inactivation process in vivo in respect to cholinesterase inhibitory activity. PMID:25849329

  7. Digestibility and Bioavailability of the Active Components of Erica australis L. Aqueous Extracts and Their Therapeutic Potential as Acetylcholinesterase Inhibitors

    PubMed Central

    Dias, Pilar; Falé, Pedro L.; Martins, Alice; Rauter, Amélia P.

    2015-01-01

    Erica australis L. (Ericaceae) is used in traditional medicine to treat many free-radical related ailments. In the present work, the stability and biological activity of the plant aqueous extracts submitted to an in vitro digestive process were investigated. Chemical stability was monitored by HPLC-DAD and LC-MS/MS, while the bioactivities were evaluated through the inhibition of acetylcholinesterase (AChE) and DPPH radical scavenging activity. Both extracts, whose main components were flavonol glycosides, inhibited AChE, showing IC50 values of 257.9 ± 6.2 µg/mL and 296.8 ± 8.8 µg/mL for the decoction and for the infusion, respectively. Significant radical scavenging activities were also revealed by both extracts, as denoted by the IC50 values for the decoction, 6.7 ± 0.1 µg/mL, and for the infusion, 10.5 ± 0.3 µg/mL. After submission to gastric and pancreatic juices, no remarkable alterations in the composition or in the bioactivities were observed, suggesting that the extracts may pass through the gastrointestinal tract, keeping their composition and therefore their biological properties. Moreover, the bioavailability of the components of both extracts, as studied in a Caco-2 cell model, showed that compounds can permeate the membrane, which is a condition to exert their biological activities. Our results add further support to the potential of E. australis for its antioxidant and neuroprotective properties. PMID:26347794

  8. Brain regional acetylcholinesterase activity and muscarinic acetylcholine receptors in rats after repeated administration of cholinesterase inhibitors and its withdrawal

    SciTech Connect

    Kobayashi, Haruo . E-mail: hk1664@iwate-u.ac.jp; Suzuki, Tadahiko; Sakamoto, Maki; Hashimoto, Wataru; Kashiwada, Keiko; Sato, Itaru; Akahori, Fumiaki; Satoh, Tetsuo

    2007-03-15

    Activity of acetylcholinesterase (AChE) and specific binding of [{sup 3}H]quinuclidinyl benzilate (QNB), [{sup 3}H]pirenzepine (PZP) and [{sup 3}H]AF-DX 384 to muscarinic acetylcholine receptor (mAChR) preparations in the striatum, hippocampus and cortex of rats were determined 1, 6 and 11 days after the last treatment with an organophosphate DDVP, a carbamate propoxur or a muscarinic agonist oxotremorine as a reference for 7 and 14 days. AChE activity was markedly decreased in the three regions 1 day after the treatment with DDVP for 7 and 14 days with a gradual recovery 6 to 11 days, and much less decreased 1, 6 and 11 days after the treatment with propoxur for 7 days but not for 14 days in the hippocampus and cortex. The binding of [{sup 3}H]-QNB, PZP and AF-DX 384 in the three regions was generally decreased by the treatment with DDVP for 7 and 14 days. Such down-regulations were generally restored 6 or 11 days after the treatment for 7 but not for 14 days. The down-regulation or up-regulation as measured by [{sup 3}H]-QNB, PZP and AF-DX 384 was observed 1, 6 or 11 days after treatment with propoxur for 7 days and/or 14 days. Repeated treatment with oxotremorine produced similar effects except AChE activity to DDVP. These results suggest that repeated inhibition of AChE activity may usually cause down-regulation of mAChRs with some exception in the hippocampus when a reversible antiChE propoxur is injected.

  9. In situ monitoring of myenteric neuron activity using acetylcholinesterase-modified AlGaN/GaN solution-gate field-effect transistors.

    PubMed

    Müntze, Gesche Mareike; Pouokam, Ervice; Steidle, Julia; Schäfer, Wladimir; Sasse, Alexander; Röth, Kai; Diener, Martin; Eickhoff, Martin

    2016-03-15

    The response characteristics of acetylcholinesterase-modified AlGaN/GaN solution-gate field-effect transistors (AcFETs) are quantitatively analyzed by means of a kinetic model. The characterization shows that the covalent enzyme immobilization process yields reproducible AcFET characteristics with a Michaelis constant KM of (122 ± 4) μM for the immobilized enzyme layer. The increase of KM by a factor of 2.4 during the first four measurement cycles is attributed to partial denaturation of the enzyme. The AcFETs were used to record the release of acetylcholine (ACh) by neuronal tissue cultivated on the gate area upon stimulation by rising the extracellular K(+) concentration. The neuronal tissue constituted of isolated myenteric neurons from four to 12 days old Wistar rats, or sections from the muscularis propria containing the myenteric plexus from adult rats. For both cases the AcFET response was demonstrated to be related to the activity of the immobilized acetylcholinesterase using the reversible acetylcholinesterase blocker donepezil. A concentration response curve of this blocking agent revealed a half maximal inhibitory concentration of 40 nM which is comparable to values measured by complementary in vitro methods. PMID:26547432

  10. Larvicidal and acetylcholinesterase inhibitory activities of apiaceae plant essential oils and their constituents against aedes albopictus and formulation development.

    PubMed

    Seo, Seon-Mi; Jung, Chan-Sik; Kang, Jaesoon; Lee, Hyo-Rim; Kim, Sung-Woong; Hyun, Jinho; Park, Il-Kwon

    2015-11-18

    This study evaluated the larvicidal activity of 12 Apiaceae plant essential oils and their components against the Asian tiger mosquito, Aedes albopictus, and the inhibition of acetylcholine esterase with their components. Of the 12 plant essential oils tested, ajowan (Trachyspermum ammi), caraway seed (Carum carvi), carrot seed (Daucus carota), celery (Apium graveolens), cumin (Cuminum cyminum), dill (Anethum graveolens), and parsley (Petroselinum sativum) resulted in >90% larval mortality when used at 0.1 mg/mL. Of the compounds identified, α-phellandrene, α-terpinene, p-cymene, (-)-limonene, (+)-limonene, γ-terpinene, cuminaldehyde, neral, (S)-+-carvone, trans-anethole, thymol, carvacrol, myristicin, apiol, and carotol resulted in >80% larval mortality when used at 0.1 mg/mL. Two days after treatment, 24.69, 3.64, and 12.43% of the original amounts of the celery, cumin, and parsley oils, respectively, remained in the water. Less than 50% of the original amounts of α-phellandrene, 1,8-cineole, terpinen-4-ol, cuminaldehyde, and trans-antheole were detected in the water at 2 days after treatment. Carvacrol, α-pinene, and β-pinene inhibited the activity of Ae. albopictus acetylcholinesterase with IC50 values of 0.057, 0.062, and 0.190 mg/mL, respectively. A spherical microemulsion of parsley essential oil-loaded poly(vinyl alcohol) (PVA) was prepared, and the larvicidal activity of this formulation was shown to be similar to that of parsley oil. PMID:26500081

  11. Differences between male and female rhesus monkey erythrocyte acetylcholinesterase and plasma cholinesterase activity before and after exposure to sarin

    SciTech Connect

    Woodard, C.L.; Calamaio, C.A.; Kaminskis, A.; Anderson, D.R.; Harris, L.W.

    1993-05-13

    The female rhesus monkey has a menstrual cycle like the human. Additionally, several differences in enzyme levels between males and females and in the female during the menstrual cycle are present. Therefore we quantitated plasma cholinesterase (ChE/BuChE) and erythrocyte (RBC) acetylcholinesterase (AChE) activity before and after exposure to sarin (GB)(1 5 ug/kg, iv; a 0.75 LD50), in male and female rhesus (Macaca mulatta) monkeys. Twenty-eight-day preexposure baseline plasma ChE and RBC AChE values for six male and six female rhesus monkeys were compared for intra-animal, within sex and between sex differences. After these baseline values were obtained, the organophosphorus (OP) compound/Isopropyl methylphosphono-fluoridate (GB) was administered to atropinized monkeys to determine if there was a significant in vivo difference between the sexes in their response to this intoxication in regard to the rate of BuChE /AChE inhibition, pyridine-2-aldoxime methyl chloride (2-PAM) reactivation of the phosphonylated BuChE and the rate of aging of the phosphonylated:BuChE/AChE. In the pre-exposure portion of the protocol; the intra-animal and intra-group BuChE/AChE variations were found to be minimal; but there were significant differences between the male and female monkeys in both plasma BuChE and RBC AChE levels; although probably clinically insignificant in respect to an OP intoxication. No significant cyclic fluctuations were seen during the 28-day study in either sex.

  12. Ortho-7 bound to the active-site gorge of free and OP-conjugated acetylcholinesterase: cation-π interactions.

    PubMed

    Pathak, Arup Kumar; Bandyopadhyay, Tusar

    2016-01-01

    Despite the immense importance of cation-π interactions prevailing in bispyridinium drug acetylcholinesterase (AChE) complexes, a precise description of cation-π interactions at molecular level has remained elusive. Here, we consider a bispyridinium drug, namely, ortho-7 in three different structures of AChE, with and without complexation with organophosphorus (OP) compounds for detailed investigation using all atom molecular dynamics simulation. By quantum mechanical calculations, Y72, W86, Y124, W286, Y337, and Y341 aromatic residues of the enzyme are investigated for possible cation-π interactions with ortho-7. The cation-π interactions in each of the protein-drug complexes are studied using distance, angle, a suitable functional form of them, and electrostatic criteria. The variation of cation-π functional is remarkably consistent with that of the Columbic variation. It is clearly observed that cation-π interactions for some of the residues in the catalytic active site (CAS) and peripheral anionic site (PAS) of the enzyme are either enhanced or reduced based on the nature of OP conjugation (i.e., nerve gas, tabun or pesticide, fenamiphos) when compared with the OP-free enzyme. The strength of cation-π interaction is strongly dependent on the type OP conjugation. The effect of conjugation at CAS is also seen to influence the cation-π interaction at the PAS region. The variation of cation-π interactions on the type of conjugating OP compounds might be suggestive of a reason as to why wide spectrum drug against any OP poisoning is yet to arrive in the market. PMID:26270602

  13. Acetylcholinesterase activity in the sexually dimorphic area of the gerbil brain: sex differences and influences of adult gonadal steroids.

    PubMed

    Commins, D; Yahr, P

    1984-03-20

    The morphology of the medial preoptic area-anterior hypothalamus (MPOA-AH) of gerbils is sexually dimorphic and influenced by adult gonadal hormones. This research shows that the distribution of (MPOA-AH) cells that synthesize acetylcholinesterase (AChE) and the activity of AChE within the MPOA-AH are also sexually dimorphic and hormone sensitive. Adult male and female gerbils were gonadectomized, gonadectomized and implanted subcutaneously with testosterone (T), or sham operated 4-8 weeks before sacrifice. Coronal sections through the sexually dimorphic area (SDA) of the MPOA-AH were stained for AChE. Planimeter measurements of camera lucida drawings showed that the total volume of the SDA is similar in the two sexes, but the proportion of the SDA that stains darkly and/or stands out clearly from the surround (dark volume) is larger in males. Optical density readings also indicated that AChE staining is darker in the male SDA. Gonadectomy decreases staining intensity in both sexes and reduces total SDA volume. Dark volume decreases more than 50%. Testosterone treatment reverses all effects of gonadectomy, although hormonal influences are smaller in females than in males. There were no sex differences or hormonal influences on AChE staining lateral to the SDA. The pars compacta of the male SDA was essentially devoid of AChE, indicating that this cell group is distinct from the rest of the SDA. It also shrinks after castration unless the males receive T. Histochemical changes in the SDA may be related to hormonal control of scent marking, a form of communication in this species. PMID:6715576

  14. Linarin Inhibits the Acetylcholinesterase Activity In-vitro and Ex-vivo.

    PubMed

    Feng, Xinchi; Wang, Xin; Liu, Youping; Di, Xin

    2015-01-01

    Linarin is a flavone glycoside in the plants Flos chrysanthemi indici, Buddleja officinalis, Cirsium setosum, Mentha arvensis and Buddleja davidii, and has been reported to possess analgesic, antipyretic, anti-inflammatory and neuroprotective activities. In this paper, linarin was investigated for its AChE inhibitory potential both in-vitro and ex-vivo. Ellman's colorimetric method was used for the determination of AChE inhibitory activity in mouse brain. In-vitro assays revealed that linarin inhibited AChE activity with an IC50 of 3.801 ± 1.149 μM. Ex-vivo study showed that the AChE activity was significantly reduced in both the cortex and hippocampus of mice treated intraperitoneally with various doses of linarin (35, 70 and 140 mg/Kg). The inhibition effects produced by high dose of linarin were the same as that obtained after huperzine A treatment (0.5 mg/Kg). Molecular docking study revealed that both 4'-methoxyl group and 7-O-sugar moiety of linarin played important roles in ligand-receptor binding and thus they are mainly responsible for AChE inhibitory activity. In view of its potent AChE inhibitory activity, linarin may be a promising therapeutic agent for the treatment of some diseases associated with AChE, such as glaucoma, myasthenia gravis, gastric motility and Alzheimer's disease. PMID:26330885

  15. Linarin Inhibits the Acetylcholinesterase Activity In-vitro and Ex-vivo

    PubMed Central

    Feng, Xinchi; Wang, Xin; Liu, Youping; Di, Xin

    2015-01-01

    Linarin is a flavone glycoside in the plants Flos chrysanthemi indici, Buddleja officinalis, Cirsium setosum, Mentha arvensis and Buddleja davidii, and has been reported to possess analgesic, antipyretic, anti-inflammatory and neuroprotective activities. In this paper, linarin was investigated for its AChE inhibitory potential both in-vitro and ex-vivo. Ellman’s colorimetric method was used for the determination of AChE inhibitory activity in mouse brain. In-vitro assays revealed that linarin inhibited AChE activity with an IC50 of 3.801 ± 1.149 μM. Ex-vivo study showed that the AChE activity was significantly reduced in both the cortex and hippocampus of mice treated intraperitoneally with various doses of linarin (35, 70 and 140 mg/Kg). The inhibition effects produced by high dose of linarin were the same as that obtained after huperzine A treatment (0.5 mg/Kg). Molecular docking study revealed that both 4’-methoxyl group and 7-O-sugar moiety of linarin played important roles in ligand-receptor binding and thus they are mainly responsible for AChE inhibitory activity. In view of its potent AChE inhibitory activity, linarin may be a promising therapeutic agent for the treatment of some diseases associated with AChE, such as glaucoma, myasthenia gravis, gastric motility and Alzheimer’s disease. PMID:26330885

  16. [A structure-activity study of a catalytic antiidiotypic antibody to the human erythrocyte acetylcholinesterase].

    PubMed

    Aleksandrova, E S; Koralevski, F; Titov, M I; Demin, A V; Kozyr', A V; Kolesnikov, A V; Tramontano, A; Paul, S; Thomas, D; Gabibov, A G; Gnuchev, N V; Friboulet, A

    2002-01-01

    The catalytic monoclonal antibody 9A8 (MA 9A8), antiidiotypic to the antibody AE-2 (MA AE2) produced to the active site of acetyl cholinesterase from human erythrocytes, was subjected to a structure-function study. The specific binding of MA 9A8 to MA AE2 (K 2.26 x 10(9) M-1) was shown by the method of surface plasmon resonance, and the functional activity of MA 9A8 was demonstrated. Unlike acetyl cholinesterase, this antibody specifically reacted with the irreversible phosphonate inhibitors of esterases. A peptide map of MA 9A8 was analyzed by MALDI mass spectrometry. The Ser99 residue of its heavy chain was shown to be within the active site of the catalytic antibody. A computer modeling of the MA 9A8 active site suggested the existence of a catalytic dyad formed by Ser99 and His35. A comparison of the tertiary structures of the MA 9A8 and the 17E8 monoclonal antibody, which also exhibited an esterase activity and was produced to the stable analogue of the reaction transition state, indicated a practically complete coincidence of the structures of their presumed active sites. PMID:11962233

  17. Comparison of the oxime-induced reactivation of rhesus monkey, swine and guinea pig erythrocyte acetylcholinesterase following inhibition by sarin or paraoxon, using a perfusion model for the real-time determination of membrane-bound acetylcholinesterase activity.

    PubMed

    Herkert, Nadja M; Lallement, Guy; Clarençon, Didier; Thiermann, Horst; Worek, Franz

    2009-04-28

    Recently, a dynamically working in vitro model with real-time determination of membrane-bound human acetylcholinesterase (AChE) activity was shown to be a versatile model to investigate oxime-induced reactivation kinetics of organophosphate- (OP) inhibited enzyme. In this assay, AChE was immobilized on particle filters which were perfused with acetylthiocholine, Ellman's reagent and phosphate buffer. Subsequently, AChE activity was continuously analyzed in a flow-through detector. Now, it was an intriguing question whether this model could be used with erythrocyte AChE from other species in order to investigate kinetic interactions in the absence of annoying side reactions. Rhesus monkey, swine and guinea pig erythrocytes were a stable and highly reproducible enzyme source. Then, the model was applied to the reactivation of sarin- and paraoxon-inhibited AChE by obidoxime or HI 6 and it could be shown that the derived reactivation rate constants were in good agreement to previous results obtained from experiments with a static model. Hence, this dynamic model offers the possibility to investigate highly reproducible interactions between AChE, OP and oximes with human and animal AChE. PMID:19428926

  18. Assessment of acetylcholinesterase and butyrylcholinesterase activities in blood plasma of agriculture workers

    PubMed Central

    Dhananjayan, V.; Ravichandran, B.; Anitha, N.; Rajmohan, H. R.

    2012-01-01

    Background: Cholinesterase determination indicates whether the person has been under pesticide exposure is not. It is recommended that the worker′s cholinesterase level should be assessed for workers at a pesticide applied region. Hence, cholinesterase activities in blood samples of agricultural workers exposed to vegetables and grape cultivation with age matched, unexposed workers, who never had any exposure to pesticides, were estimated. Methods: The detailed occupational history and lifestyle characters were obtained by questionnaire. Cholinesterase activity was determined by the method of Ellman as modified by Chambers and Chambers. Results: AChE was ranging from 1.65 to 3.54μmoles/min/ml in exposed subjects where as it was ranged from 2.22 to 3.51μmoles/min/ml in control subjects. BChE activity was ranging from 0.16 to 5.2μmoles/min/ml among exposed subjects, where as it was ranged from 2.19 to 5.06μmoles/min/ml in control subjects. The results showed statistically significant reduction in enzyme activities (AChE 14%; BChE 56%) among exposed subjects. Conclusion: It was concluded that the reduction in cholinesterase activity may lead to varieties of effects. Hence it is compulsory to use protective gadgets during pesticide spray. Further a continuous biomonitoring study is recommended to assess pesticide exposure. PMID:23776322

  19. Is fast fiber innervation responsible for increased acetylcholinesterase activity in reinnervating soleus muscles?

    NASA Technical Reports Server (NTRS)

    Misulis, K. E.; Dettbarn, W. D.

    1985-01-01

    An investigation was conducted as to whether the predominantly slow SOL, which is low in AChE activity, is initially reinnervated by axons that originally innervated fast muscle fibers with high AChE activity, such as those of the EDL. Local denervation of the SOL in the guinea pig was performed because this muscle is composed solely of slow (type I) fibers; thereby virtually eliminating the possibility of homologous muscle fast fiber innervation. The overshoot in this preparation was qualitatively similar to that seen with distal denervation in the guinea pig and local and distal denervation in the rat. Thus, initial fast fiber innvervation is not responsible for the patterns of change in AChE activity seen with reinnervation in the SOL. It is concluded that the neural control of AChe is different in these two muscles and may reflect specific differences in the characteristics of AChE regulation in fast and slow muscle.

  20. Coimmobilization of acetylcholinesterase and choline oxidase on gold nanoparticles: stoichiometry, activity, and reaction efficiency.

    PubMed

    Keighron, Jacqueline D; Åkesson, Sebastian; Cans, Ann-Sofie

    2014-09-30

    Hybrid structures constructed from biomolecules and nanomaterials have been used in catalysis and bioanalytical applications. In the design of many chemically selective biosensors, enzymes conjugated to nanoparticles or carbon nanotubes have been used in functionalization of the sensor surface for enhancement of the biosensor functionality and sensitivity. The conditions for the enzyme:nanomaterial conjugation should be optimized to retain maximal enzyme activity, and biosensor effectiveness. This is important as the tertiary structure of the enzyme is often altered when immobilized and can significantly alter the enzyme catalytic activity. Here we show that characterization of a two-enzyme:gold nanoparticle (AuNP) conjugate stoichiometry and activity can be used to gauge the effectiveness of acetylcholine detection by acetylcholine esterase (AChE) and choline oxidase (ChO). This was done by using an analytical approach to quantify the number of enzymes bound per AuNP and monitor the retained enzyme activity after the enzyme:AuNP synthesis. We found that the amount of immobilized enzymes differs from what would be expected from bulk solution chemistry. This analysis was further used to determine the optimal ratio of AChE:ChO added at synthesis to achieve optimum sequential enzyme activity for the enzyme:AuNP conjugates, and reaction efficiencies of greater than 70%. We here show that the knowledge of the conjugate stoichiometry and retained enzyme activity can lead to more efficient detection of acetylcholine by controlling the AChE:ChO ratio bound to the gold nanoparticle material. This approach of optimizing enzyme gold nanoparticle conjugates should be of great importance in the architecture of enzyme nanoparticle based biosensors to retain optimal sensor sensitivity. PMID:25167196

  1. Seasonal brain acetylcholinesterase activity in three species of shorebirds overwintering in Texas

    USGS Publications Warehouse

    Mitchell, C.A.; White, D.H.

    1982-01-01

    There was no seasonal variation in average brain AChE activity for the 3 species of wild birds collected between October and February. Further work needs to be done, however, covering an even broader time frame which includes the reproductive cycle. It appears that some birds feeding at the mouth of an agricultural drain, at some distance from the nearest pesticide applications, were affected by AChE inhibitors.

  2. Neurotoxic effects of nickel chloride in the rainbow trout brain: Assessment of c-Fos activity, antioxidant responses, acetylcholinesterase activity, and histopathological changes.

    PubMed

    Topal, Ahmet; Atamanalp, Muhammed; Oruç, Ertan; Halıcı, Mesut Bünyami; Şişecioğlu, Melda; Erol, Hüseyin Serkan; Gergit, Arzu; Yılmaz, Bahar

    2015-06-01

    The aim of this study was to determine the biochemical, immunohistochemical, and histopathological effects of nickel chloride (Ni) in the rainbow trout brain. Fish were exposed to Ni concentrations (1 mg/L and 2 mg/L) for 21 days. At the end of the experimental period, brain tissues were taken from all fish for c-Fos activity and histopathological examination and determination of acetylcholinesterase (AChE), superoxide dismutase (SOD), catalase (CAT) enzyme activities, lipid peroxidation (LPO), and glutathione (GSH) levels. Our results showed that Ni treatment caused a significant increase in the brain SOD activity and in LPO and GSH levels (p < 0.05), but it significantly decreased AChE and CAT enzyme activities (p < 0.05). Strong induction in c-Fos was observed in some cerebral and cerebellar regions of fish exposed to Ni concentrations when compared with the control group. However, c-Fos activity was decreased in necrotic Purkinje cells. Brain tissues were characterized by demyelination and necrotic changes. These results suggested that Ni treatment causes oxidative stress, changes in c-Fos activity, and histopathological damage in the fish brain. PMID:25666867

  3. Effects of immature cashew nut-shell liquid (Anacardium occidentale) against oxidative damage in Saccharomyces cerevisiae and inhibition of acetylcholinesterase activity.

    PubMed

    De Lima, S G; Feitosa, C M; Citó, A M G L; Moita Neto, J M; Lopes, J A D; Leite, A S; Brito, M C; Dantas, S M M; Cavalcante, A A C Melo

    2008-01-01

    The cashew tree (Anacardium occidentale) represents one of the major cheapest sources of non-isoprenoid phenolic lipids, which have a variety of biological properties: they can act as molluscicides, insecticides, fungicides, have anti-termite properties, have medicinal applications, and demonstrate antioxidant activity in vitro. Immature cashew nut-shell liquid (iCNSL) is a unique natural source of unsaturated long-chain phenols. Their use has stimulated much research in order to prepare drug analogues for application in several fields. The objective of the present study was to determine whether iCNSL has antioxidant properties when used in strains of the yeast Saccharomyces cerevisiae and to measure the inhibitory activity of acetylcholinesterase. The constituents were identified using thin-layer chromatography, gas chromatography-mass spectrometry, Fourier transform infrared spectroscopy, and (1)H and (13)C nuclear magnetic resonance. The iCNSL contains anacardic acid, cardanol, cardol, and 2-methyl cardol. Immature cashew nut oil contains triacylglycerols, fatty acids, alkyl-substituted phenols, and cholesterol. The main constituents of the free fatty acids are palmitic (C(16:0)) and oleic acid (C(18:1)). iCNSL has excellent protective activities in strains of S. cerevisiae against oxidative damage induced by hydrogen peroxide and inhibits acetylcholinesterase activity. iCNSL may have an important role in protecting DNA against damage induced by reactive oxygen species, as well as hydrogen peroxide, generated by intra- and extracellular mechanisms. PMID:18949700

  4. Acetylcholinesterase activity in the earthworm Eisenia andrei at different conditions of carbaryl exposure.

    PubMed

    Gambi, Naimj; Pasteris, Andrea; Fabbri, Elena

    2007-05-01

    Recent reports have stressed the need for a better understanding of earthworm biomarker responses. We aimed at investigating acethylcholinesterase (AChE) activity in the earthworm Eisenia andrei after exposure to carbaryl or its commercial formulation Zoril 5 under different in vitro and in vivo experiments. In addition, lysosome membrane stability was assessed by neutral red retention assay in the same experimental conditions. AChE basal Km and Vm values were about 0.16 mM and 41 nmol min(-1) mg protein(-1), respectively. Carbaryl dose-dependently decreased Vmax, while not affecting Km values. Carbaryl reduced earthworm AChE activity within 1 day of in vivo exposure to contaminated filter paper. Tested on soil, carbaryl inhibited AChE with the maximum effect after 3 days; in contrast, lysosome membrane stability of coelomocytes indicated a maximum toxicity after one day, followed by a recovery. AChE inhibition by Zoril 5 was highest after one day, while lysosome membrane stability declined progressively. In all cases, carbaryl dose-dependently decreased Vmax while not affecting Km values. In conclusion, E. andrei AChE activity assessed in vitro is dose-dependently inhibited by the carbamate compound carbaryl, which acts as a pure competitive inhibitor. In vivo experiments suggested that pure and co-formulated carbaryl have different time and/or dose dependent effects on earthworms. Our results further support the use of AChE inhibition as an indicator of pesticide contamination, to be included in a battery of biomarkers for monitoring soil toxicity. PMID:17428735

  5. AOP description: Acetylcholinesterase inhibition

    EPA Science Inventory

    This adverse outcome pathway (AOP) leverages existing knowledge in the open literature to describe the linkage between inhibition of acetylcholinesterase (AChE) and the subsequent mortality resulting from impacts at cholinergic receptors. The AOP takes a chemical category approa...

  6. Acute effects of acephate and methamidophos on acetylcholinesterase activity, endocrine system and amino acid concentrations in rats.

    PubMed

    Spassova, D; White, T; Singh, A K

    2000-05-01

    Acute effects of acephate (Ace) and methamidophos (Met) on acetylcholinesterase activity, endocrine system and amino acid concentrations were studied in rats. The rats were injected intraperitoneally with Ace (500 mg/kg) or Met (5 mg/kg) and then sacrificed at 15 or 60 min after the injection (A15 and A60 for Ace and M15 and M60 for Met). The primary aim of this study was to determine whether the mammalian toxicity of Ace is solely due to its conversion to Met or the protection of Ace against Met-inhibited AChE is also an important factor. The second aim of this study was to study the effects of Ace and Met on the endocrine system and amino acid concentrations and whether or not these effects correlate with AChE inhibition and Met accumulation. The Ace or Met injected animals did not exhibit the signs of organophosphate (OP) poisoning within 15 min after the injection, but exhibited tremors at 45 min after the injection. Blood and brain AChE activity in A15 and M15 rats exhibited 55 to 75% inhibition while the enzyme activity in A60 and M60 rats exhibited 80 to 95% inhibition. Ace was metabolized to Met in rats both in vivo and in vitro. A 5 rats had significantly higher Met concentration in their liver, brain and adrenal glands compared to M 5 rats, and A60 rats had significantly higher Met concentrations in their blood, liver, brain and adrenal glands compared to M60 rats. Thus, tissue Met concentrations in Ace-treated rats were significantly higher than in Met-treated rats and the inhibition of AChE activity was not consistent with the amount of metabolically formed Met, supporting the hypothesis that the Ace protection plays a role in the overall toxicity. Ace and Met both impaired circulating blood hormone and amino acid concentrations in rats. The endocrine effects of Ace and Met differed from their cholinergic effects, and were not proportional to the amount of Met present in different tissues obtained from the treatment groups. Plasma ACTH concentration was

  7. Positive allosteric modulators of α7 nicotinic acetylcholine receptors affect neither the function of other ligand- and voltage-gated ion channels and acetylcholinesterase, nor β-amyloid content.

    PubMed

    Arias, Hugo R; Ravazzini, Federica; Targowska-Duda, Katarzyna M; Kaczor, Agnieszka A; Feuerbach, Dominik; Boffi, Juan C; Draczkowski, Piotr; Montag, Dirk; Brown, Brandon M; Elgoyhen, Ana Belén; Jozwiak, Krzysztof; Puia, Giulia

    2016-07-01

    The activity of positive allosteric modulators (PAMs) of α7 nicotinic acetylcholine receptors (AChRs), including 3-furan-2-yl-N-p-tolyl-acrylamide (PAM-2), 3-furan-2-yl-N-o-tolylacrylamide (PAM-3), and 3-furan-2-yl-N-phenylacrylamide (PAM-4), was tested on a variety of ligand- [i.e., human (h) α7, rat (r) α9α10, hα3-containing AChRs, mouse (m) 5-HT3AR, and several glutamate receptors (GluRs)] and voltage-gated (i.e., sodium and potassium) ion channels, as well as on acetylcholinesterase (AChE) and β-amyloid (Aβ) content. The functional results indicate that PAM-2 inhibits hα3-containing AChRs (IC50=26±6μM) with higher potency than that for NR1aNR2B and NR1aNR2A, two NMDA-sensitive GluRs. PAM-2 affects neither the activity of m5-HT3ARs, GluR5/KA2 (a kainate-sensitive GluR), nor AChE, and PAM-4 does not affect agonist-activated rα9α10 AChRs. Relevant clinical concentrations of PAM-2-4 do not inhibit Nav1.2 and Kv3.1 ion channels. These PAMs slightly enhance the activity of GluR1 and GluR2, two AMPA-sensitive GluRs. PAM-2 does not change the levels of Aβ42 in an Alzheimer's disease mouse model (i.e., 5XFAD). The molecular docking and dynamics results using the hα7 model suggest that the active sites for PAM-2 include the intrasubunit (i.e., PNU-120596 locus) and intersubunit sites. These results support our previous study showing that these PAMs are selective for the α7 AChR, and clarify that the procognitive/promnesic/antidepressant activity of PAM-2 is not mediated by other targets. PMID:27129924

  8. Sesquiterpenes and a monoterpenoid with acetylcholinesterase (AchE) inhibitory activity from Valeriana officinalis var. latiofolia in vitro and in vivo.

    PubMed

    Chen, Heng-Wen; He, Xuan-Hui; Yuan, Rong; Wei, Ben-Jun; Chen, Zhong; Dong, Jun-Xing; Wang, Jie

    2016-04-01

    Acetylcholinesterase Inhibitor (AchEI) is the most extensive in all anti-dementia drugs. The extracts and isolated compounds from the Valeriana genus have shown anti-dementia bioactivity. Four new sesquiterpenoids (1-4) and a new monoterpenoid (5) were isolated from the root of Valeriana officinalis var. latiofolia. The acetylcholinesterase (AchE) inhibitory activity of isolates was evaluated by modified Ellman method in vitro. Learning and memory ability of compound 4 on mice was evaluated by the Morris water maze. The contents of acetylcholine (Ach), acetylcholine transferase (ChAT) and AchE in mice brains were determined by colorimetry. The results showed IC50 of compound 4 was 0.161 μM in vitro. Compared with the normal group, the learning and memory ability of mice and the contents of Ach and ChAT decreased in model group mice (P<0.01), while the AchE increased (P<0.01). Compared with the model group, Ach and ChAT in the positive control group, the high-dose group and the medium-dose group increased (P<0.01), while the AchE decreased (P<0.01). Compound 4 can improve the learning and memory abilities of APPswe/PSΔE9 double-transgenic mice, and the mechanism may be related to the regulation of the relative enzyme in the cholinergic system. PMID:26976216

  9. (I) Pharmacological profiling of a novel modulator of the α7 nicotinic receptor: Blockade of a toxic acetylcholinesterase-derived peptide increased in Alzheimer brains.

    PubMed

    Garcia-Ratés, Sara; Morrill, Paul; Tu, Henry; Pottiez, Gwenael; Badin, Antoine-Scott; Tormo-Garcia, Cristina; Heffner, Catherine; Coen, Clive W; Greenfield, Susan A

    2016-06-01

    The primary cause of Alzheimer's disease is unlikely to be the much studied markers amyloid beta or tau. Their widespread distribution throughout the brain does not account for the specific identity and deep subcortical location of the primarily vulnerable neurons. Moreover an unusual and intriguing feature of these neurons is that, despite their diverse transmitters, they all contain acetylcholinesterase. Here we show for the first time that (1) a peptide derived from acetylcholinesterase, with independent trophic functions that turn toxic in maturity, is significantly raised in the Alzheimer midbrain and cerebrospinal fluid; (2) a synthetic version of this peptide enhances calcium influx and eventual production of amyloid beta and tau phosphorylation via an allosteric site on the α7 nicotinic receptor; (3) a synthetic cyclic version of this peptide is neuroprotective against the toxicity not only of its linear counterpart but also of amyloid beta, thereby opening up the prospect of a novel therapeutic approach. PMID:26867503

  10. Aphicidal Activity of Illicium verum Fruit Extracts and Their Effects on the Acetylcholinesterase and Glutathione S-transferases Activities in Myzus persicae (Hemiptera: Aphididae).

    PubMed

    Zhou, Ben-Guo; Wang, Sa; Dou, Ting-Ting; Liu, Su; Li, Mao-Ye; Hua, Ri-Mao; Li, Shi-Guang; Lin, Hua-Feng

    2016-01-01

    This study aims to explore the aphicidal activity and underlying mechanism of Illicium verum Hook. f. that is used as both food and medicine. The contact toxicity of the extracts from I. verum fruit with methyl alcohol (MA), ethyl acetate (EA), and petroleum ether (PE) against Myzus persicae (Sulzer), and the activities of acetylcholinesterase (AChE) and glutathione S-transferases (GSTs) of M. persicae after contact treatment were tested. The results showed that MA, EA, and PE extracts of 1.000 mg/l caused, respectively, M. persicae mortalities of 68.93%, 89.95% and 74.46%, and the LC50 of MA, EA, and PE extracts were 0.31, 0.14 and 0.27 mg/l at 72 h after treatment, respectively; the activities of AChE and GSTs in M. persicae were obviously inhibited by the three extracts, as compared with the control, with strong dose and time-dependent effects, the inhibition rates on the whole reached more than 50.00% at the concentration of 1.000 mg/l at 72 h after treatment. The inhibition of the extracts on AChE and GSTs activities (EA extract > PE extract > MA extract) were correlated with theirs contact toxic effects, so it is inferred that the decline of the metabolic enzymes activities may be one of important reasons of M. persicae death. The study results suggested that I. verum extracts have potential as a eco-friendly biopesticide in integrated pest management against M. persicae. PMID:26826651

  11. Aphicidal Activity of Illicium verum Fruit Extracts and Their Effects on the Acetylcholinesterase and Glutathione S-transferases Activities in Myzus persicae (Hemiptera: Aphididae)

    PubMed Central

    Zhou, Ben-Guo; Wang, Sa; Dou, Ting-Ting; Liu, Su; Li, Mao-Ye; Hua, Ri-Mao; Li, Shi-Guang; Lin, Hua-Feng

    2016-01-01

    This study aims to explore the aphicidal activity and underlying mechanism of Illicium verum Hook. f. that is used as both food and medicine. The contact toxicity of the extracts from I. verum fruit with methyl alcohol (MA), ethyl acetate (EA), and petroleum ether (PE) against Myzus persicae (Sulzer), and the activities of acetylcholinesterase (AChE) and glutathione S-transferases (GSTs) of M. persicae after contact treatment were tested. The results showed that MA, EA, and PE extracts of 1.000 mg/l caused, respectively, M. persicae mortalities of 68.93%, 89.95% and 74.46%, and the LC50 of MA, EA, and PE extracts were 0.31, 0.14 and 0.27 mg/l at 72 h after treatment, respectively; the activities of AChE and GSTs in M. persicae were obviously inhibited by the three extracts, as compared with the control, with strong dose and time-dependent effects, the inhibition rates on the whole reached more than 50.00% at the concentration of 1.000 mg/l at 72 h after treatment. The inhibition of the extracts on AChE and GSTs activities (EA extract > PE extract > MA extract) were correlated with theirs contact toxic effects, so it is inferred that the decline of the metabolic enzymes activities may be one of important reasons of M. persicae death. The study results suggested that I. verum extracts have potential as a eco-friendly biopesticide in integrated pest management against M. persicae. PMID:26826651

  12. Use of acetylcholinesterase inhibitors in Alzheimer's disease.

    PubMed

    Moghul, S; Wilkinson, D

    2001-09-01

    Alzheimer's disease is a growing problem in an aging Western world, estimated to have cost the US economy USD 1.75 trillion. Until recently, the management of Alzheimer's disease largely comprised support for the family, nursing care and the use of unlicensed medication to control behavioral disturbances. The three new acetylcholinesterase inhibitors licensed to treat Alzheimer's disease (donepezil, rivastigmine and galantamine) have provided clinicians with a major impetus to their desire to diagnose and treat this lethal disease. Their effects on cognition are proven. More recent work on the effects of acetylcholinesterase inhibitors on behavioral symptoms, activities of daily living and caregiver burden have also been encouraging. Emerging work indicates their likely efficacy in other dementias (e.g., vascular dementia, dementia with Lewy bodies). This review summarizes the evidence concerning the impact of acetylcholinesterase inhibitors in dementia both currently and over the next 5 years. PMID:19811047

  13. Quantitative structure-activity analysis of acetylcholinesterase inhibition by oxono and thiono analogues of organophosphorus compounds. (Reannouncement with new availability information)

    SciTech Connect

    Maxwell, D.M.; Brecht, K.M.

    1992-02-01

    A comparison of the bimolecular rate constants (ki) for inhibition of electric eel acetylcholinesterase (AChE) by the oxono (i.e., P=O) and thiono (i.e., P=S) analogues of parathion, methylparathion, leptophos, fonofos, sarin, and soman revealed that the oxono/thiono ratios of ki values varied from 14 for soman to 1240 for parathion. Analysis of the relative importance of the dissociation equilibrium constant and the phosphorylation rate constant in producing this variation in ki values indicated that the oxono analogues had phosphorylation rate constant values that varied in a narrow range from 8- to 14-fold greater than their thiono counterparts, while the oxono/thiono ratios for dissociation constants varied widely from 1 for soman to 82 for fonofos. The lower affinities of thiono analogues for AChE probably resulted from differences in the hydrophobic binding of oxono and thiono analogues to the active site of AChE, inasmuch as the hydrophobicities (i.e., octanol/water partition coefficients) of thiono organophosphorus compounds were much greater than the hydrophobicities of their oxono analogues. Quantitative structure-activity analysis indicated that the hydrophobic effects of oxono and thiono moieties correlated with log ki for AChE inhibition to a greater extent (r2 = 0.79) than their electronic effects (r2 equal to or less than 0.48). These observations suggest that the differences in hydrophobicity of oxono and thiono analogues of organophosphorus compounds may be as important as their electronic differences in determining their effectiveness as AChE inhibitors. Acetylcholinesterase, soman (GD), structure-activity analysis inhibition, oxono analogues, thiono analogues.

  14. Use and disuse and the control of acetylcholinesterase activity in fast and slow twitch muscle of rat

    NASA Technical Reports Server (NTRS)

    Dettbarn, W. D.; Groswald, D.; Gupta, R. C.; Misulis, K. E.

    1985-01-01

    The role of acetylcholinesterase (AChE) in neuromuscular transmission is relatively well established, little is known, however, of the mechanisms that regulate its synthesis and control its specific distribution in fast and slow muscle. Innervation plays an important role in the regulation of AChE and elimination of the influence of the nerve by surgical denervation results in a loss of AChE. The influences of the nerve and how they are mediated was investigated. It is suggested that muscle usage and other factors such as materials carried by axonal transport may participate in the regulation of this enzyme. The mechanisms that regulate AChE and its molecular forms in two functionally different forms are studied.

  15. Cyperus rotundus extract inhibits acetylcholinesterase activity from animal and plants as well as inhibits germination and seedling growth in wheat and tomato.

    PubMed

    Sharma, Rashmi; Gupta, Rajendra

    2007-05-30

    Cyperus rotundus (nutgrass) is the world's worst invasive weed through tubers. Its success in dominating natural habitats depends on its ability to prevent herbivory, and to kill or suppress other plants growing in its vicinity. The present study was done to investigate whether chemicals in nutgrass target neuronal and non-neuronal acetylcholinesterases to affect surrounding animals and plants respectively. Methanolic extract of tubers of nutgrass strongly inhibited activity of AChE from electric eel, wheat and tomato. It also inhibited seed germination and seedling growth in wheat and tomato. Our results suggest that inhibitor of AChE in nutgrass possibly acts as agent of plant's war against (a) herbivore animals, and (b) other plants trying to grow in the same habitat. An antiAChE from nutgrass has been purified by employing chromatography and crystallization. The structural determination of the purified inhibitor is in progress. PMID:17367818

  16. C- and O-glycosyl flavonoids in Sanguinello and Tarocco blood orange (Citrus sinensis (L.) Osbeck) juice: Identification and influence on antioxidant properties and acetylcholinesterase activity.

    PubMed

    Barreca, Davide; Gattuso, Giuseppe; Laganà, Giuseppina; Leuzzi, Ugo; Bellocco, Ersilia

    2016-04-01

    Sanguinello and Tarocco are the blood orange (Citrus sinensis (L.) Osbeck) cultivars most diffused worldwide. Reversed phase liquid chromatography coupled with MS-MS analysis showed that these two varieties have a similar chromatographic pattern, characterised by the presence of C- and O-glycosyl flavonoids. Of the two, Sanguinello was found to be far richer in flavonoids than Tarocco. In the juices, twelve individual components were identified for the first time, namely, four C-glycosyl flavones (lucenin-2, vicenin-2, stellarin-2, lucenin-2 4'-methyl ether and scoparin), three flavonol derivatives (quercetin-3-O-(2-rhamnosyl)-rutinoside, quercetin-3-O-hexoside, quercetin 3-hydroxy-3-methylglutaryl-glycoside), an O-triglycosyl flavanone (narirutin 4'-O-glucoside) and a flavone O-glycosides (chrysoeriol 7-O-neoesperidoside). Moreover, the influence of the identified C- and O-glycosyl flavonoids on the antioxidant and acetylcholinesterase activity of these juices has been evaluated. PMID:26593535

  17. Concentration-dependent interactions of the organophosphates chlorpyrifos oxon and methyl paraoxon with human recombinant acetylcholinesterase

    SciTech Connect

    Kaushik, R.; Rosenfeld, Clint A.; Sultatos, L.G. . E-mail: sultatle@umdnj.edu

    2007-06-01

    For many decades it has been thought that oxygen analogs (oxons) of organophosphorus insecticides phosphorylate the catalytic site of acetylcholinesterase by a mechanism that follows simple Michaelis-Menten kinetics. More recently, the interactions of at least some oxons have been shown to be far more complex and likely involve binding of oxons to a second site on acetylcholinesterase that modulates the inhibitory capacity of other oxon molecules at the catalytic site. The current study has investigated the interactions of chlorpyrifos oxon and methyl paraoxon with human recombinant acetylcholinesterase. Both chlorpyrifos oxon and methyl paraoxon were found to have k {sub i}'s that change as a function of oxon concentration. Furthermore, 10 nM chlorpyrifos oxon resulted in a transient increase in acetylthiocholine hydrolysis, followed by inhibition. Moreover, in the presence of 100 nM chlorpyrifos oxon, acetylthiocholine was found to influence both the K {sub d} (binding affinity) and k {sub 2} (phosphorylation constant) of this oxon. Collectively, these results demonstrate that the interactions of chlorpyrifos oxon and methyl paraoxon with acetylcholinesterase cannot be described by simple Michaelis-Menten kinetics but instead support the hypothesis that these oxons bind to a secondary site on acetylcholinesterase, leading to activation/inhibition of the catalytic site, depending on the nature of the substrate and inhibitor. Additionally, these data raise questions regarding the adequacy of estimating risk of low levels of insecticide exposure from direct extrapolation of insecticide dose-response curves since the capacity of individual oxon molecules at low oxon levels could be greater than individual oxon molecules in vivo associated with the dose-response curve.

  18. Acetylcholinesterase activity in the host-parasite system of the cod Gadus morhua and acanthocephalan Echinorhynchus gadi from the southern Baltic Sea.

    PubMed

    Podolska, M; Nadolna, K; Szostakowska, B

    2014-02-15

    Acetylcholinesterase (AChE) activity measurement is widely used as a specific biomarker of neurotoxic effects. The aim of this study was to evaluate AChE activity in a host fish (the cod) and its acanthocephalan parasite Echinorhynchus gadi from the southern Baltic. AChE activity in hosts and parasites was inversely related: the highest cod AChE activity corresponded to the lowest E. gadi enzymatic activity and vice versa ("mirror effect"). This is the first report on the simultaneous application of this biomarker in cod and its acanthocephalan parasites. Results obtained for the host-parasite system are complementary and provide comprehensive information about the response of this biomarker. Analysis of the system allows for detection of a greater number of factors influencing AChE activity in the marine environment than separate analysis of the host and parasites. Thus, AChE activity measurement in a host-parasite system may be considered to be a promising tool for biomonitoring. PMID:24393378

  19. Leukotriene activity modulation in asthma.

    PubMed

    Spector, S L

    1997-09-01

    Leukotrienes constitute a class of inflammatory mediators synthesised from arachidonic acid, a product of cell membrane metabolism. Synthesis occurs in the 5-lipoxygenase enzyme pathway, which produces several species of leukotrienes, each with characteristic biological activities. With regard to asthma, the leukotrienes are particularly important because of their ability to directly and potently mediate bronchoconstriction; in addition, they specifically stimulate the secretion of mucus into the airways and the extravasation of fluids and proteins into the airway tissues, both of which contribute to airway obstruction. A number of antileukotriene agents have been developed with the goal of modulating the inflammatory process in various disease states. These agents fall into 2 general classes: leukotriene receptor antagonists and leukotriene synthesis inhibitors. Results of antileukotriene agents in preclinical and clinical trials indicate that antileukotriene agents attenuate the response to challenges with inhaled leukotrienes, cold air, exercise, aspirin and allergen; in addition, they have shown efficacy in clinical asthma and have not been associated with serious adverse effects. Although results to date indicate that these medications are well tolerated and effective in the treatment of asthma, the recent approval by the FDA of 2 antileukotriene agents will give physicians further insight into how patients with asthma respond to them. PMID:9279501

  20. Inhibitory Effects of Sodium Arsenite and Acacia Honey on Acetylcholinesterase in Rats

    PubMed Central

    Odunola, Oyeronke A.; Gbadegesin, Michael A.; Sallau, Abdullahi B.; Ndidi, Uche S.; Ibrahim, Mohammed A.

    2015-01-01

    This study was conducted to investigate the effect of sodium arsenite and Acacia honey on acetylcholinesterase (AChE) activity and electrolytes in the brain and serum of Wistar rats. Male Wistar albino rats in four groups of five rats each were treated with distilled water, sodium arsenite (5 mg/kg body weight), Acacia honey (20% v/v), and sodium arsenite and Acacia honey, daily for one week. The sodium arsenite and Acacia honey significantly (P < 0.05) decreased AChE activity in the brain with the combined treatment being more potent. Furthermore, sodium arsenite and Acacia honey significantly (P < 0.05) decreased AChE activity in the serum. Strong correlation was observed between the sodium and calcium ion levels with acetylcholinesterase activity in the brain and serum. The gas chromatography mass spectrometry analysis of Acacia honey revealed the presence of a number of bioactive compounds such as phenolics, sugar derivatives, and fatty acids. These findings suggest that sodium arsenite and/or Acacia honey modulates acetylcholinesterase activities which may be explored in the management of Alzheimer's diseases but this might be counteracted by the hepatotoxicity induced by arsenics. PMID:25821630

  1. Submillimeter Confocal Imaging Active Module

    NASA Technical Reports Server (NTRS)

    Hong, John; Mehdi, Imran; Siegel, Peter; Chattopadhyay, Goutam; Cwik, Thomas; Rowell, Mark; Hacker, John

    2009-01-01

    The term submillimeter confocal imaging active module (SCIAM) denotes a proposed airborne coherent imaging radar system that would be suitable for use in reconnaissance, surveillance, and navigation. The development of the SCIAM would include utilization and extension of recent achievements in monolithic microwave integrated circuits capable of operating at frequencies up to and beyond a nominal radio frequency of 340 GHz. Because the SCIAM would be primarily down-looking (in contradistinction to primarily side-looking), it could be useful for imaging shorter objects located between taller ones (for example, objects on streets between buildings). The SCIAM would utilize a confocal geometry to obtain high cross-track resolution, and would be amenable to synthetic-aperture processing of its output to obtain high along-track resolution. The SCIAM (see figure) would include multiple (two in the initial version) antenna apertures, separated from each other by a cross-track baseline of suitable length (e.g., 1.6 m). These apertures would both transmit the illuminating radar pulses and receive the returns. A common reference oscillator would generate a signal at a controllable frequency of (340 GHz + (Delta)f)/N, where (Delta)f is an instantaneous swept frequency difference and N is an integer. The output of this oscillator would be fed to a frequency- multiplier-and-power-amplifier module to obtain a signal, at 340 GHz + (Delta)f, that would serve as both the carrier signal for generating the transmitted pulses and a local-oscillator (LO) signal for a receiver associated with each antenna aperture. Because duplexers in the form of circulators or transmit/receive (T/R) switches would be lossy and extremely difficult to implement, the antenna apertures would be designed according to a spatial-diplexing scheme, in which signals would be coupled in and out via separate, adjacent transmitting and receiving feed horns. This scheme would cause the transmitted and received beams

  2. Activation of phosphorothionate pesticides based on a cytochrome P450 BM-3 (CYP102 A1) mutant for expanded neurotoxin detection in food using acetylcholinesterase biosensors.

    PubMed

    Schulze, Holger; Schmid, Rolf D; Bachmann, Till T

    2004-03-15

    A novel enzymatic in vitro activation method for phosphorothionates has been developed to allow their detection with acetylcholinesterase (AChE) biosensors. Activation is necessary because this group of insecticides shows nearly no inhibitory effect toward AChE in their pure nonmetabolized form. In contrast, they exert a strong inhibitory effect on AChE after oxidation as it takes place by metabolic activation in higher organisms. Standard chemical methods to oxidize phosphorothionates showed inherent disadvantages that impede their direct use in food analysis. In contrast, a genetically engineered triple mutant of P450 BM-3 (CYP102 A1) could convert the two frequently used insecticides parathion and chlorpyrifos into their oxo variants as was confirmed by GC/MS measurements. The wild-type protein was unable to do so. In the case of chlorpyrifos, the enzymatic activation was as good as the chemical oxidation. In the case of parathion, the P450 activation was more efficient than the oxidation by NBS but neither activation method yielded an AChE inhibition that was as high as with paraoxon. The application of the method to infant food in combination with a disposable AChE biosensor enabled detection of chlorpyrifos and parathion at concentrations down to 20 microg/kg within an overall assay time of 95 min. PMID:15018574

  3. Identical kinetics of human erythrocyte and muscle acetylcholinesterase with respect to carbamate pre-treatment, residual activity upon soman challenge and spontaneous reactivation after withdrawal of the inhibitors.

    PubMed

    Herkert, Nadja M; Eckert, Saskia; Eyer, Peter; Bumm, Rudolf; Weber, Georg; Thiermann, Horst; Worek, Franz

    2008-04-18

    The efficacy of oxime treatment in soman poisoning is limited due to rapid aging of inhibited acetylcholinesterase (AChE). Pre-treatment with carbamates was shown to improve antidotal treatment substantially. Recently, by using a dynamically working in vitro model with real-time determination of membrane-bound AChE activity, we were able to demonstrate that pre-inhibition of human erythrocyte AChE with pyridostigmine or physostigmine resulted in a markedly higher residual AChE activity after inhibition by soman or paraoxon than in the absence of reversible inhibitors. The purpose of the present study was to compare the effect of carbamate pre-treatment and soman challenge with human erythrocyte and muscle homogenate AChE. Both enzyme sources were immobilized on particle filters which were perfused with acetylthiocholine, Ellman's reagent and phosphate buffer. AChE activity was continuously analyzed in a flow-through detector. Pre-inhibition of AChE with pyridostigmine or physostigmine resulted in a concentration-dependent increase in carbamylation, residual activity after soman inhibition and fraction of decarbamylation AChE after discontinuation of the inhibitors without differences between human erythrocyte and muscle AChE. This data support the view that human erythrocyte AChE is an adequate surrogate marker for synaptic AChE in OP poisoning. PMID:18304715

  4. Active combustion flow modulation valve

    DOEpatents

    Hensel, John Peter; Black, Nathaniel; Thorton, Jimmy Dean; Vipperman, Jeffrey Stuart; Lambeth, David N; Clark, William W

    2013-09-24

    A flow modulation valve has a slidably translating hollow armature with at least one energizable coil wound around and fixably attached to the hollow armature. The energizable coil or coils are influenced by at least one permanent magnet surrounding the hollow armature and supported by an outer casing. Lorentz forces on the energizable coils which are translated to the hollow armature, increase or decrease the flow area to provide flow throttling action. The extent of hollow armature translation depends on the value of current supplied and the direction of translation depends on the direction of current flow. The compact nature of the flow modulation valve combined with the high forces afforded by the actuator design provide a flow modulation valve which is highly responsive to high-rate input control signals.

  5. The effects of rivastigmine plus selegiline on brain acetylcholinesterase, (Na+, K+)-, Mg2+-ATPase activities, antioxidant status, and learning performance of aged rats

    PubMed Central

    Carageorgiou, Haris; Sideris, Antonios C; Messari, Ioanna; Liakou, Chrissoula I; Tsakiris, Stylianos

    2008-01-01

    We investigated the effects of rivastigmine (a cholinesterase inhibitor) and selegiline ((-)deprenyl, an irreversible inhibitor of monoamineoxidase-B), alone and in combination, on brain acetylcholinesterase (AChE), (Na+, K+)-, Mg2+-ATPase activities, total antioxidant status (TAS), and learning performance, after long-term drug administration in aged male rats. The possible relationship between the biochemical and behavioral parameters was evaluated. Methods Aged rats were treated (for 36 days) with rivastigmine (0.3 mg/kg rat/day ip), selegiline (0.25 mg/kg rat/day im), rivastigmine plus selegiline in the same doses and way of administration as separately. Aged and adult control groups received NaCl 0.9% 0.5 ml ip. Results TAS was lower in aged than in adult rats, rivastigmine alone does not affect TAS, decreases AChE activity, increases (Na+, K+)-ATPase and Mg2+-ATPase activity of aged rat brain and improves cognitive performance. Selegiline alone decreases free radical production and increases AChE activity and (Na+, K+)-ATPase activity, improving cognitive performance as well. In the combination: rivastigmine seems to cancel selegiline action on TAS and AChE activity, while it has additive effect on (Na+, K+)-ATPase activity. In the case of Mg2+-ATPase selegiline appears to attenuate rivastigmine activity. No statistically significant difference was observed in the cognitive performance. Conclusion Reduced TAS, AChE activity and learning performance was observed in old rats. Both rivastigmine and selesiline alone improved performance, although they influenced the biochemical parameters in a different way. The combination of the two drugs did not affect learning performance. PMID:19043511

  6. Health Activities Project (HAP): Breathing Fitness Module.

    ERIC Educational Resources Information Center

    Buller, Dave; And Others

    Contained within this Health Activities Project (HAP) learning packet are activities for children in grades 5-8. Design of the activities centers around the idea that students can control their own health and safety. Within this module are teacher and student folios describing four activities which involve students in learning how to measure their…

  7. Effects of harmine, an acetylcholinesterase inhibitor, on spatial learning and memory of APP/PS1 transgenic mice and scopolamine-induced memory impairment mice.

    PubMed

    He, Dandan; Wu, Hui; Wei, Yue; Liu, Wei; Huang, Fei; Shi, Hailian; Zhang, Beibei; Wu, Xiaojun; Wang, Changhong

    2015-12-01

    Harmine, a β-carboline alkaloid present in Peganum harmala with a wide spectrum of pharmacological activities, has been shown to exert strong inhibition against acetylcholinesterase in vitro. However, whether it can rescue the impaired cognition has not been elucidated yet. In current study, we examined its effects on scopolamine-induced memory impairment mice and APP/PS1 transgenic mice, one of the models for Alzheimer's disease, using Morris Water Maze test. In addition, whether harmine could penetrate blood brain barrier, interact with and inhibit acetylcholinesterase, and activate downstream signaling network was also investigated. Our results showed that harmine (20mg/kg) administered by oral gavage for 2 weeks could effectively enhance the spatial cognition of C57BL/6 mice impaired by intraperitoneal injection of scopolamine (1mg/kg). Meanwhile, long-term consumption of harmine (20mg/kg) for 10 weeks also slightly benefited the impaired memory of APP/PS1 mice. Furthermore, harmine could pass through blood brain barrier, penetrate into the brain parenchyma shortly after oral administration, and modulate the expression of Egr-1, c-Jun and c-Fos. Molecular docking assay disclosed that harmine molecule could directly dock into the catalytic active site of acetylcholinesterase, which was partially confirmed by its in vivo inhibitory activity on acetylcholinesterase. Taken together, all these results suggested that harmine could ameliorate impaired memory by enhancement of cholinergic neurotransmission via inhibiting the activity of acetylcholinesterase, which may contribute to its clinical use in the therapy of neurological diseases characterized with acetylcholinesterase deficiency. PMID:26526348

  8. Highly Sensitive and Selective Immuno-capture/Electrochemical Assay of Acetylcholinesterase Activity in Red Blood Cells: A Biomarker of Exposure to Organophosphorus Pesticides and Nerve Agents

    SciTech Connect

    Chen, Aiqiong; Du, Dan; Lin, Yuehe

    2012-02-09

    Acetylcholinesterase (AChE) enzyme activity in red blood cells (RBCs) is a useful biomarker for biomonitoring of exposures to organophosphorus (OP) pesticides and chemical nerve agents. In this paper, we reported a new method for AChE activity assay based on selective immuno-capture of AChE from biological samples followed by enzyme activity assay of captured AChE using a disposable electrochemical sensor. The electrochemical sensor is based on multiwalled carbon nanotubes-gold nanocomposites (MWCNTs-Au) modified screen printed carbon electrode (SPCE). Upon the completion of immunoreaction, the target AChE (including active and inhibited) is captured onto the electrode surface and followed by an electrochemical detection of enzymatic activity in the presence of acetylthiocholine. A linear response is obtained over standard AChE concentration range from 0.1 to 10 nM. To demonstrate the capability of this new biomonitoring method, AChE solutions dosed with different concentration of paraoxon were used to validate the new AChE assay method. AChE inhibition in OP dosed solutions was proportional to its concentration from 0.2 to 50 nM. The new AChE activity assay method for biomonitoring of OP exposure was further validated with in-vitro paraoxon-dosed RBC samples. The established electrochemical sensing platform for AChE activity assay not only avoids the problem of overlapping substrate specificity with esterases by using selective antibody, but also eliminates potential interference from other electroactive species in biological samples. It offers a new approach for sensitive, selective, and rapid AChE activity assay for biomonitoring of exposures to OPs.

  9. Water Extractable Phytochemicals from Peppers (Capsicum spp.) Inhibit Acetylcholinesterase and Butyrylcholinesterase Activities and Prooxidants Induced Lipid Peroxidation in Rat Brain In Vitro

    PubMed Central

    Ogunruku, Omodesola O.; Ademosun, Ayokunle O.

    2014-01-01

    Background. This study sought to investigate antioxidant capacity of aqueous extracts of two pepper varieties (Capsicum annuum var. accuminatum (SM) and Capsicum chinense (RO)) and their inhibitory effect on acetylcholinesterase and butyrylcholinesterase activities. Methods. The antioxidant capacity of the peppers was evaluated by the 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging ability and ferric reducing antioxidant property. The inhibition of prooxidant induced lipid peroxidation and cholinesterase activities in rat brain homogenates was also evaluated. Results. There was no significant difference (P > 0.05) in the total phenol contents of the unripe and ripe Capsicum spp. extracts. Ripe and unripe SM samples had significantly higher (P < 0.05) ABTS* scavenging ability than RO samples, while the ripe fruits had significantly higher (P < 0.05) ferric reducing properties in the varieties. Furthermore, the extracts inhibited Fe2+ and quinolinic acid induced lipid peroxidation in rats brain homogenates in a dose-dependent manner. Ripe and unripe samples from SM had significantly higher AChE inhibitory abilities than RO samples, while there was no significant difference in the BuChE inhibitory abilities of the pepper samples. Conclusion. The antioxidant and anticholinesterase properties of Capsicum spp. may be a possible dietary means by which oxidative stress and symptomatic cognitive decline associated with neurodegenerative conditions could be alleviated. PMID:26904640

  10. Fumigant toxicity of Oriental sweetgum (Liquidambar orientalis) and valerian (Valeriana wallichii) essential oils and their components, including their acetylcholinesterase inhibitory activity, against Japanese termites (Reticulitermes speratus).

    PubMed

    Park, Il-Kwon

    2014-01-01

    This study investigated the fumigant toxicity of oriental sweetgum (Liquidambar orientalis) and valerian (Valeriana wallichii) essential oils and their components against the Japanese termite (Reticulitermes speratus). The fumigant toxicity of oriental sweetgum and valerian oil differed significantly according to exposure time. Oriental sweetgum showed toxicity at short exposure times (2 days), and the toxicity of valerian oil was high 7 days after treatment. The main constituents of oriental sweetgum and valerian oils were tested individually for their fumigant toxicity against Japanese termites. Among the test compounds, benzyl alcohol, acetophenone, 1-phenyl-1-ethanol, hydrocinnamyl alcohol, trans-cinnamyl aldehyde, trans-cinnamyl alcohol, cis-asarone, styrene, and cis-ocimene showed toxicity against Japanese termites 7 days after treatment. Hydrocinnamyl alcohol and trans-cinnamyl alcohol were found to be the major contributors to the fumigant antitermitic toxicity of oriental sweetgum oil. The acetylcholinesterase (AChE) inhibition activity of two oils and their constituents was tested to determine their mode of action. Only cis-ocimene showed strong AChE inhibition activity with an IC50 value of 0.131 mg/mL. Further studies are warranted to determine the potential of these essential oils and their constituents as fumigants for termite control. PMID:25153870

  11. Water Extractable Phytochemicals from Peppers (Capsicum spp.) Inhibit Acetylcholinesterase and Butyrylcholinesterase Activities and Prooxidants Induced Lipid Peroxidation in Rat Brain In Vitro.

    PubMed

    Ogunruku, Omodesola O; Oboh, Ganiyu; Ademosun, Ayokunle O

    2014-01-01

    Background. This study sought to investigate antioxidant capacity of aqueous extracts of two pepper varieties (Capsicum annuum var. accuminatum (SM) and Capsicum chinense (RO)) and their inhibitory effect on acetylcholinesterase and butyrylcholinesterase activities. Methods. The antioxidant capacity of the peppers was evaluated by the 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging ability and ferric reducing antioxidant property. The inhibition of prooxidant induced lipid peroxidation and cholinesterase activities in rat brain homogenates was also evaluated. Results. There was no significant difference (P > 0.05) in the total phenol contents of the unripe and ripe Capsicum spp. extracts. Ripe and unripe SM samples had significantly higher (P < 0.05) ABTS(*) scavenging ability than RO samples, while the ripe fruits had significantly higher (P < 0.05) ferric reducing properties in the varieties. Furthermore, the extracts inhibited Fe(2+) and quinolinic acid induced lipid peroxidation in rats brain homogenates in a dose-dependent manner. Ripe and unripe samples from SM had significantly higher AChE inhibitory abilities than RO samples, while there was no significant difference in the BuChE inhibitory abilities of the pepper samples. Conclusion. The antioxidant and anticholinesterase properties of Capsicum spp. may be a possible dietary means by which oxidative stress and symptomatic cognitive decline associated with neurodegenerative conditions could be alleviated. PMID:26904640

  12. Inhibition of acetylcholinesterase activity in the central nervous system of the red swamp crayfish, Procambarus clarkii, by mercury, cadmium, and lead

    SciTech Connect

    Devi, M.; Fingerman, M.

    1995-11-01

    The toxicological, physiological and biochemical responses of aquatic crustaceans to heavy metals have been reported by several investigators. Levels of glucose, lactic acid, sodium, potassium, aspartate aminotransferase and alanine aminotransferase in the blood of the crab Scylla serrata increased, while glycogen levels in hepatopancreas and muscle decreased after a four-week exposure to mercuric chloride. In fiddler crab, Uca pugilator, enzyme activity was observed to decrease in the hepatopancreas but increased in abdominal muscle after 48 hr cadmium exposure. In the red swamp crayfish, Procambarus clarkii, exposed for 96 hr to cadmium, glutahione (GSH) level and GSH S-transferase activity deceased in the midgut. In crayfish Astacus astacus exposed to sublethal concentrations of lead and cadmium, oxidative enzyme (succine dehydrogenase and NADPH-cytochrome P450 reductase) activities in gills and hepatopancrease decreased. Acetylcholinesterase (AChE) inhibition by organophosphates and organocarbamates in various crustaceans has bee reported. In vivo cadmium exposure caused increases in esterase activities, but mercury exposure decreases these activities in the hepatopancreas of the shrimp Callianassa tyrrhena. The freshwater crab, Barytelphusa guerini, exposed to 0.6 ppm cadmium showed reduced oxygen consumption throughout the experiment whereas AChE activity increased after 4 days but decreased after 15 days. The authors wanted to determine the effects of cadmium, lead and mercury on AChE activity in central nervous tissue of Procambarus clarkii. This enzyme has the potential for serving both as a biochemical indicator of toxic stress and a sensitive parameter for testing water for the presence of toxicants. These three biologically silent metals have, according to Schweinsberg and Karsa great toxicological significance to humans because their use is widespread. 14 refs., 4 figs.

  13. Performance Based Education. Technology Activity Modules.

    ERIC Educational Resources Information Center

    Custer, Rodney L., Ed.

    These Technology Activity Modules are designed to serve as an implementation resource for technology education teachers as they integrate technology education with Missouri's Academic Performance Standards and provide a source of activities and activity ideas that can be used to integrate and reinforce learning across the curriculum. The modules…

  14. DEVELOPMENT OF REFERENCE RANGES FOR PLASMA TOTAL CHOLINESTERASE AND BRAIN ACETYLCHOLINESTERASE ACTIVITY IN FREE-RANGING CARNABY'S BLACK-COCKATOOS (CALYPTORHYNCHUS LATIROSTRIS).

    PubMed

    Vaughan-Higgins, Rebecca; Vitali, Simone; Reiss, Andrea; Besier, Shane; Hollingsworth, Tom; Smith, Gerard

    2016-07-01

    Published avian reference ranges for plasma cholinesterase (ChE) and brain acetylcholinesterase (AChE) are numerous. However, a consistently reported recommendation is the need for species- and laboratory-specific reference ranges because of variables, including assay methods, sample storage conditions, season, and bird sex, age, and physiologic status. We developed normal reference ranges for brain AChE and plasma total ChE (tChE) activity for Carnaby's Black-Cockatoos (Calyptorhynchus latirostris) using a standardized protocol (substrate acetylthiocholine at 25 C). We report reference ranges for brain AChE (19-41 μmol/min per g, mean 21±6.38) and plasma tChE (0.41-0.53 μmol/min per mL, mean 0.47±0.11) (n=15). This information will be of use in the ongoing field investigation of a paresis-paralysis syndrome in the endangered Carnaby's Black-Cockatoos, suspected to be associated with exposure to anticholinesterase compounds and add to the paucity of reference ranges for plasma tChE and brain AChE in Australian psittacine birds. PMID:27195690

  15. A fluorescence assay for measuring acetylcholinesterase activity in rat blood and a human neuroblastoma cell line (SH-SY5Y).

    PubMed

    Santillo, Michael F; Liu, Yitong

    2015-01-01

    Acetylcholinesterase (AChE) is an enzyme responsible for metabolism of the neurotransmitter acetylcholine, and inhibition of AChE can have therapeutic applications (e.g., drugs for Alzheimer's disease) or neurotoxic consequences (e.g., pesticides). A common absorbance-based AChE activity assay that uses 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) can have limited sensitivity and be prone to interference. Therefore, an alternative assay was developed, in which AChE activity was determined by measuring fluorescence of resorufin produced from coupled enzyme reactions involving acetylcholine and Amplex Red (10-acetyl-3,7-dihydroxyphenoxazine). The Amplex Red assay was used for two separate applications. First, AChE activity was measured in rat whole blood, which is a biomarker for exposure to AChE inhibitor pesticides. Activity was quantified from a 10(5)-fold dilution of whole blood, and there was a linear correlation between Amplex Red and DTNB assays. For the second application, Amplex Red assay was used to measure AChE inhibition potency in a human neuroblastoma cell line (SH-SY5Y), which is important for assessing pharmacological and toxicological potential of AChE inhibitors including drugs, phytochemicals, and pesticides. Five known reversible inhibitors were evaluated (IC50, 7-225 nM), along with irreversible inhibitors chlorpyrifos-oxon (ki=1.01 nM(-1)h(-1)) and paraoxon (ki=0.16 nM(-1)h(-1)). Lastly, in addition to inhibition, AChE reactivation was measured in SH-SY5Y cells incubated with pralidoxime chloride (2-PAM). The Amplex Red assay is a sensitive, specific, and reliable fluorescence method for measuring AChE activity in both rat whole blood and cultured SH-SY5Y cells. PMID:26165232

  16. In situ induced metal-enhanced fluorescence: a new strategy for biosensing the total acetylcholinesterase activity in sub-microliter human whole blood.

    PubMed

    Ma, KeKe; Lu, Lu; Qi, Zongli; Feng, Jingjing; Zhuo, Caixia; Zhang, Yaodong

    2015-06-15

    Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities (i.e., total AChE) in human blood are biomarkers for theranostic monitoring of organophosphate neurotoxin-poisoned patients. We developed an ultra-sensitive method to detect the total AChE activity in sub-microliter human whole blood based on in situ induced metal-enhanced fluorescence (MEF). Both AChE and BChE can catalyze the hydrolysis of the acetylthiocholine (ATCh) substrate and produce positively-charged thiocholine (TCh). TCh can reverse the negatively-charged surface of core-shell Ag@SiO2 nanoparticles (NPs). The negatively-charged fluorescent dye (8-hydroxypyrene-1,3,6-trisulfonic acid, HPTS) is then confined to the surface of Ag@SiO2 NPs and generates an enhanced fluorescence signal in situ. Changes in the surface charge of Ag@SiO2 NPs are monitored by Zeta potential, and the MEF effect is confirmed by the measurements of fluorescence time decay. AChE activity has a dynamic range of 0 U/mL to 0.005 U/mL and a detection limit of 0.05 mU/mL. The total AChE activity in the sub-microliter human whole blood could be determined; the results were further validated. Therefore, combining the AChE catalytic reaction with MEF provides a simple, ultra-sensitive, and cost-effective "in situ MEF" approach to determine the total AChE activity in human whole blood sample down to sub-microliters without matrix interferences. The strategy also allows potential usage in other tissues and other fields. PMID:25660508

  17. Effects of exposure to oxamyl, carbofuran, dichlorvos, and lindane on acetylcholinesterase activity in the gills of the Pacific oyster Crassostrea gigas.

    PubMed

    Anguiano, Gerardo A; Amador, Alejandro; Moreno-Legorreta, Manuel; Arcos-Ortega, Fabiola; Vazquez-Boucard, Celia

    2010-08-01

    Acetylcholinesterase (AChE) activity has been used to test the exposure of mollusk bivalves to pesticides and other pollutants. The Pacific oyster Crassostrea gigas is a species with a worldwide distribution, and it has a high commercial value. The use of this species as a bioindicator in the marine environment, and the use of measurements of AChE activity in tissues of C. gigas require prior evaluation of organisms exposed to several toxic compounds in the laboratory. In our study, the effects of pesticides on AChE activity in the gills and mantle tissues of C. gigas were analyzed by exposing animals to organophosphate (dichlorvos), carbamate (carbofuran and oxamyl), and organochlorine (lindane) pesticides. Adult Pacific oysters were exposed to several concentrations (0.1-200 microM) of dichlorvos, carbofuran, and oxamyl for 96 h, and lindane (1.0 and 2.5 microM) was applied for 12 days. In gill tissues, all pesticides analyzed caused a decrease in AChE activity when compared to the control unexposed group. The mean inhibition concentration (IC(50)) values were determined for dichlorvos, carbofuran, and oxamyl pesticides. Dichlorvos had the highest toxic effect, with an IC(50) of 1.08 microM; lesser effects were caused by oxamyl and carbofuran, with IC(50)s of 1.67 and 3.03 microM, respectively. This study reports the effects of pesticides with several chemical structures and validates measurement of AChE activity in the gill tissues of C. gigas for use in environmental evaluations or food quality tests. PMID:19449386

  18. Biphasic photoelectrochemical sensing strategy based on in situ formation of CdS quantum dots for highly sensitive detection of acetylcholinesterase activity and inhibition.

    PubMed

    Hou, Ting; Zhang, Lianfang; Sun, Xinzhi; Li, Feng

    2016-01-15

    Herein, we reported a facile and highly sensitive biphasic photoelectrochemical (PEC) sensing strategy based on enzymatic product-mediated in situ formation of CdS quantum dots (QDs), and assayed the activity and inhibition of acetylcholinesterase (AChE) in its optimal state. Upon the hydrolysis of acetylthiocholine catalyzed by AChE, the product thiocholine stabilizes the in situ formation of CdS QDs in homogenous solution. Due to the electrostatic attraction, the resulting tertiary amino group-functionalized CdS QDs are attached to the surface of the negatively charged indium tin oxide (ITO) electrode, generating significant PEC response upon illumination in the presence of electron donors. By taking full advantage of the in situ formation of CdS QDs in homogenous solution, this strategy is capable of detecting AChE activity and inhibition in its optimal state. A directly measured detection limit of 0.01mU/mL for AChE activity is obtained, which is superior to those obtained by some fluorescence methods. The inhibition of AChE activity by aldicarb is successfully detected, and the corresponding IC50 is determined to be 13μg/L. In addition to high sensitivity and good selectivity, this strategy also exhibits additional advantages of simplicity, low cost and easy operation. To the best of our knowledge, the as-proposed strategy is the first example demonstrating the application of CdS QDs formed in situ for biphasic PEC detection of enzyme activity and inhibition. More significantly, it opens up a new horizon for the development of homogenous PEC sensing platforms, and has great potential in probing many other analytes. PMID:26339933

  19. Gold nanoclusters-Cu(2+) ensemble-based fluorescence turn-on and real-time assay for acetylcholinesterase activity and inhibitor screening.

    PubMed

    Sun, Jian; Yang, Xiurong

    2015-12-15

    Based on the specific binding of Cu(2+) ions to the 11-mercaptoundecanoic acid (11-MUA)-protected AuNCs with intense orange-red emission, we have proposed and constructed a novel fluorescent nanomaterials-metal ions ensemble at a nonfluorescence off-state. Subsequently, an AuNCs@11-MUA-Cu(2+) ensemble-based fluorescent chemosensor, which is amenable to convenient, sensitive, selective, turn-on and real-time assay of acetylcholinesterase (AChE), could be developed by using acetylthiocholine (ATCh) as the substrate. Herein, the sensing ensemble solution exhibits a marvelous fluorescent enhancement in the presence of AChE and ATCh, where AChE hydrolyzes its active substrate ATCh into thiocholine (TCh), and then TCh captures Cu(2+) from the ensemble, accompanied by the conversion from fluorescence off-state to on-state of the AuNCs. The AChE activity could be detected less than 0.05 mU/mL within a good linear range from 0.05 to 2.5 mU/mL. Our proposed fluorescence assay can be utilized to evaluate the AChE activity quantitatively in real biological sample, and furthermore to screen the inhibitor of AChE. As far as we know, the present study has reported the first analytical proposal for sensing AChE activity in real time by using a fluorescent nanomaterials-Cu(2+) ensemble or focusing on the Cu(2+)-triggered fluorescence quenching/recovery. This strategy paves a new avenue for exploring the biosensing applications of fluorescent AuNCs, and presents the prospect of AuNCs@11-MUA-Cu(2+) ensemble as versatile enzyme activity assay platforms by means of other appropriate substrates/analytes. PMID:26141104

  20. Effects of chlorpyrifos on the transcription of CYP3A cDNA, activity of acetylcholinesterase, and oxidative stress response of goldfish (Carassius auratus).

    PubMed

    Ma, Junguo; Liu, Yang; Niu, Daichun; Li, Xiaoyu

    2015-04-01

    Chlorpyrifos (CPF) is the widely used organophosphate pesticide in agriculture throughout the world. It has been found that CPF is relatively safe to human but highly toxic to fish. In this study, acute toxicity of CPF on goldfish was determined and then the transcription of goldfish cytochrome P450 (CYP) 3A was evaluated after 96 h of CPF exposure at concentrations of 15.3 [1/10 50% lethal concentration (LC50 )] or 51 μg L(-1) (1/3 LC50 ) of CPF. Meanwhile, the enzymatic activities of acetylcholinesterase (AChE), superoxide dismutase (SOD), and catalase (CAT), total antioxidant activity (T-AOC), and the contents of malondialdehyde (MDA) in the liver or brain of goldfish were also determined. The results of acute toxicity testing showed that the 96-h LC50 of CPF to the goldfish was 153 μg L(-1) . Moreover, a length sequence of 1243 bp CYP3A cDNA encoding for 413 amino acids from goldfish liver was cloned. Polymerase chain reaction results reveal that CPF exposure downregulates CYP 3A transcription in goldfish liver, suggesting that goldfish CYP 3A may be not involved in CPF bioactivation. Finally, the results of biochemical assays indicate that 96 h of CPF exposure remarkably inhibits AChE activity in fish liver or brain, alters hepatic antioxidant enzyme activities, decreases brain T-AOC, and causes lipid peroxidation in fish liver. These results suggest that oxidative stress might be involved in CPF toxicity on goldfish. PMID:24190793

  1. Development of a dynamic model for real-time determination of membrane-bound acetylcholinesterase activity upon perfusion with inhibitors and reactivators.

    PubMed

    Eckert, Saskia; Eyer, Peter; Mückter, Harald; Worek, Franz

    2006-07-28

    Quantitative predictions of the course of acetylcholinesterase (AChE) activity, following interference of inhibitors and reactivators, are usually obscured by the time-dependent changes of all reaction partners. To mimic these dynamics we developed an in vitro model. Immobilized human erythrocyte ghosts in a bioreactor were continuously perfused while AChE activity was monitored by a modified Ellman method. The perfusion system consisted of two HPLC pumps with integrated quaternary low-pressure gradient formers that were programmed by a computer using commercial HPLC software. The combined eluates passed a particle filter (Millex-GS, 0.22 microm) containing a thin layer of erythrocytes that was immersed in a temperature-controlled water bath. The effluent passed a flow cell in a UV-vis detector, the signal of which was digitized, written to disc and calculated with curve fitting programs. AChE activity decreased by 3.4% within 2.5 h. The day-to-day variation of the freshly prepared bioreactor using the same enzyme source was +/-3.3%. Residual activity of 0.2% marked the limit of quantification. Following perfusion with paraoxon, pseudo first-order rate constants of inhibition were established that did not differ from results obtained in conventional assays. The same holds true for reactivation with obidoxime. The set-up presented allows freely programmable time-dependent changes of up to eight solvents to mimic pharmacokinetic profiles without accumulation of products. Due to some hysteresis in the system, reaction half-lives should be >3 min and concentration changes in critical compounds should exceed half-lives of 5 min. Otherwise, the system offers much flexibility and operates with high precision. PMID:16725113

  2. Acotiamide Hydrochloride, a Therapeutic Agent for Functional Dyspepsia, Enhances Acetylcholine-induced Contraction via Inhibition of Acetylcholinesterase Activity in Circular Muscle Strips of Guinea Pig Stomach.

    PubMed

    Ito, K; Kawachi, M; Matsunaga, Y; Hori, Y; Ozaki, T; Nagahama, K; Hirayama, M; Kawabata, Y; Shiraishi, Y; Takei, M; Tanaka, T

    2016-04-01

    Acotiamide is a first-in-class prokinetic drug approved in Japan for the treatment of functional dyspepsia. Given that acotiamide enhances gastric motility in conscious dogs and rats, we assessed the in vitro effects of this drug on the contraction of guinea pig stomach strips and on acetylcholinesterase (AChE) activity in stomach homogenate following fundus removal. We also investigated the serotonin 5-HT4 receptor agonist mosapride, dopamine D2 receptor and AChE inhibitor itopride, and representative AChE inhibitor neostigmine. Acotiamide (0.3 and 1 μM) and itopride (1 and 3 μM) significantly enhanced the contraction of gastric body strips induced by electrical field stimulation (EFS), but mosapride (1 and 10 μM) did not. Acotiamide and itopride significantly enhanced the contraction of gastric body and antrum strips induced by acetylcholine (ACh), but not that induced by carbachol (CCh). Neostigmine also significantly enhanced the contraction of gastric body strips induced by ACh, but not that by CCh. In contrast, mosapride failed to enhance contractions induced by either ACh or CCh in gastric antrum strips. Acotiamide exerted mixed inhibition of AChE, and the percentage inhibition of acotiamide (100 μM) against AChE activity was markedly reduced after the reaction mixture was dialyzed. In contrast, itopride exerted noncompetitive inhibition on AChE activity. These results indicate that acotiamide enhances ACh-dependent contraction in gastric strips of guinea pigs via the inhibition of AChE activity, and that it exerts mixed and reversible inhibition of AChE derived from guinea pig stomach. PMID:26418413

  3. Effect of pharmaceuticals exposure on acetylcholinesterase (AchE) activity and on the expression of AchE gene in the monogonont rotifer, Brachionus koreanus.

    PubMed

    Rhee, Jae-Sung; Kim, Bo-Mi; Jeong, Chang-Bum; Park, Heum Gi; Leung, Kenneth Mei Yee; Lee, Young-Mi; Lee, Jae-Seong

    2013-11-01

    Pharmaceuticals are widely used in human and veterinary medicine. However, they are emerging as a significant contaminant in aquatic environments through wastewater. Due to the persistent and accumulated properties of pharmaceuticals via the food web, their potential harmful effects on aquatic animals are a great concern. In this study, we investigated the effects of six pharmaceuticals: acetaminophen, ATP; atenolol, ATN; carbamazepine, CBZ; oxytetracycline, OTC; sulfamethoxazole, SMX; and trimethoprim, TMP on acetylcholinesterase (AChE; EC 3.1.1.7) activity and its transcript expression with chlorpyrifos (as a positive control) in the monogonont rotifer, Brachionus koreanus. ATP, CBZ, and TMP exposure also remarkably inhibited Bk-AChE activity at 100 μg/L (24 h) and 1000 μg/L (12 h and 24 h). ATP, CBZ, and TMP exposure showed a significant decrease in the Bk-AChE mRNA level in a concentration-dependent manner. However, in the case of OTC and SMX, a slight decrease in Bk-AChE mRNA expression was found but only at the highest concentration. The time-course experiments showed that ATP positively induced Bk-AChE mRNA 12 h after exposure at both 100 and 1000 μg/L, while the Bk-AChE mRNA expression was significantly downregulated over 6 to 24 h after exposure to 1000 μg/L of CBZ, OTC, SMX, and TMP. Our findings suggest that Bk-AChE would be a useful biomarker for risk assessment of pharmaceutical compounds as an early signal of their toxicity in aquatic environments. Particularly, ATP, CBZ, and TMP may have a toxic cholinergic effect on rotifer B. koreanus by inhibiting AChE activity. PMID:24028855

  4. Effects of thyroxine and donepezil on hippocampal acetylcholine content, acetylcholinesterase activity, synaptotagmin-1 and SNAP-25 expression in hypothyroid adult rats.

    PubMed

    Wang, Fen; Zeng, Xianzhong; Zhu, Yangbo; Ning, Dan; Liu, Junxia; Liu, Chunlei; Jia, Xuemei; Zhu, Defa

    2015-02-01

    A growing number of studies have revealed that neurocognitive impairment, induced by adult-onset hypothyroidism, may not be fully restored by traditional hormone substitution therapies, including thyroxine (T4). The present study has investigated the effect of T4 and donepezil (DON; an acetylcholinesterase (AChE) inhibitor) treatment on the hypothyroidism-induced alterations of acetylcholine (ACh) content and AChE activity. Furthermore, we examined synaptotagmin-1 (syt-1) and SNAP-25 expression in the hippocampus of adult rats. Adding 0.05% propylthiouracil to their drinking water for five weeks induced hypothyroidism in the rat models. From the fourth week, the rats were treated with T4, DON or a combination of both. Concentration of ACh and the activity of AChE was determined colorimetrically. The results demonstrated that hypothyroidism induced a significant decrease of Ach content and AChE activity (by 17 and 34%, respectively), which were restored to control values by T4 administration. DON treatment also restored Ach to the normal level. Protein levels of syt-1 and SNAP-25 were determined by immunohistochemistry. The results demonstrated that syt-1 was expressed at significantly lower levels in hypothyroid rats, while SNAP-25 levels were notably higher compared with the controls. Two-week treatment with T4 alone failed to normalize the expression levels of these two proteins, while co-administration of T4 and DON was able to induce this effect. These data suggested that the thyroid hormone, T4, may have a direct effect on the metabolism of hippocampal ACh in adult rats, and that the DON treatment may facilitate the recovery of synaptic protein impairments induced by hypothyroidism. PMID:25371181

  5. Application of a dynamic in vitro model with real-time determination of acetylcholinesterase activity for the investigation of tabun analogues and oximes.

    PubMed

    Worek, Franz; Herkert, Nadja M; Koller, Marianne; Thiermann, Horst; Wille, Timo

    2015-12-25

    Tabun-inhibited acetylcholinesterase (AChE) is rather resistant towards reactivation by oximes in vitro while in vivo experiments showed some protection of animals poisoned by this chemical warfare nerve agent after treatment with an oxime and atropine. In addition, AChE inhibited by close tabun analogues, N,N-diethyltabun and N,N-di-n-propyltabun was completely resistant towards reactivation by oximes. In order to get more insight into potential mechanisms of this oxime resistance experiments with these toxic agents and the oximes obidoxime, 2-PAM, MMB-4 and HI-6 were performed utilizing a dynamic model with real-time determination of AChE activity. This experimental setup allowed the investigation of reactivation with minimized side reactions. The determined reactivation constants with tabun-inhibited human AChE were in good agreement with previously reported constants determined with a static model. N,N-diethyl- and N,N-di-n-propyltabun-inhibited human AChE could not be reactivated by oximes which indicates that the inadequate oxime effect was not due to re-inhibition by phosphonyloximes. Additional experiments with tabun-inhibited human and Rhesus monkey AChE revealed that no reactivation occurred with HI-6. These data give further support to the assumption that an interaction of tabun with residues in the active site gorge of AChE prevents effective reactivation by oximes, a mechanism which may also be the reason for the total oxime resistance of N,N-diethyl- and N,N-di-n-propyltabun-inhibited human AChE. PMID:26368669

  6. Brain acetylcholinesterase activity in shiner perch (Cymatogaster aggregata) and juvenile chinook salmon (Oncorhynchus tshawytscha) after application of carbaryl to control burrowing shrimp within Willapa Bay, Washington.

    PubMed

    Troiano, Alexandra T; King, Kerensa A; Grue, Christian E; Grassley, James M; Ekblad, Cathy J

    2013-11-01

    Carbaryl has been applied in Willapa Bay, Washington, for five decades to control burrowing shrimp (Neotrypaea californiensis and Upogebia pugettensis) on commercial oyster (Crassostrea gigas) beds. Concerns about effects on nontarget species, including fishes, have led to restrictions in use despite a lack of data on in situ exposure. We measured brain acetylcholinesterase (AChE) activity in adult Shiner perch (Cymatogaster aggregata) and juvenile Chinook salmon (Oncorhynchus tshawytscha) after operational applications. We hypothesized that exposure in Shiner perch would be greater than in juvenile Chinook salmon because of their greater site fidelity and benthic foraging. However, Shiner perch exhibited no statistically significant AChE inhibition. Enzyme activity was statistically decreased (≤14 %) in juvenile Chinook salmon after a second spray event; however, inhibition was less than that associated with overt effects and was similar to controls by 48 h after the spray. Diet analyses confirmed that Shiner perch were primarily feeding on benthic invertebrates and that juvenile Chinook salmon were feeding primarily within the water column. Composition of Shiner perch diets and amount of food consumed varied little among channels and time periods; however, Shiner perch on beds consumed more food 6 h after application than those at other time points and locations. There were no consistent differences in the diets of juvenile Chinook salmon within channels among time periods. Results suggest (1) that carbaryl applications pose little hazard to fish in the bay having habitat and dietary preferences similar to those of Shiner perch and juvenile Chinook salmon and (2) that quantification of direct exposure in the field is essential to adequately assess risk. PMID:24042340

  7. Carbon dots-assisted colorimetric and fluorometric dual-mode protocol for acetylcholinesterase activity and inhibitors screening based on the inner filter effect of silver nanoparticles.

    PubMed

    Zhao, Dan; Chen, Chuanxia; Sun, Jian; Yang, Xiurong

    2016-06-01

    In this work, we proposed an original and versatile dual-readout (colorimetric and fluorometric) protocol by means of silver nanoparticles (AgNPs) and fluorescent carbon dots (CDs), which was amenable to rapid, ultrasensitive assay of acetylcholinesterase (AChE) activity and its inhibitors. The sensing mechanism was based on the non-fluorescence state of CDs resulting from the inner filter effect (IFE) of AgNPs and the specific AChE-catalyzed hydrolysis of acetylthiocholine (ATCh) into thiocholine (TCh). Herein, the generated positively-charged and thiol-bearing TCh at trace concentration levels could trigger the aggregation of AgNPs through the well-known electrostatic and Ag-SH interactions, thereby turning the sensing solutions grey and recovering the IFE-quenched fluorescence simultaneously. Furthermore, the existence of IFE mechanism was conceivably confirmed by combining the zeta potentials, fluorescence spectra, UV-vis spectra, fluorescence lifetime and TEM measurements. As far as we know, the present study has reported the first dual-mode proposal for assessing AChE activity by using a CDs-based IFE sensing strategy, where the detection limit was as low as 0.021 mU mL(-1) and 0.016 mU mL(-1) by colorimetric and fluorometric measurements, respectively. On the other hand, the proposed assay was feasible to screen AChE inhibitors such as tacrine and carbaryl. Meanwhile, this rationally designed dual-mode sensing platform featured simplicity, rapidity, flexibility and diversity, which was demonstrated by the quantitative detection of spiked carbaryl in apple juice samples with satisfactory results. PMID:27099097

  8. Acetylcholinesterase activity in the freshwater shrimp Caridina nilotica as a biomarker of Roundup(®) herbicide pollution of freshwater systems in South Africa.

    PubMed

    Mensah, P K; Muller, W J; Palmer, C G

    2012-01-01

    The use of Caridina nilotica whole-body acetylcholinesterase (AChE) activity as a potential biomarker of Roundup(®) pollution of aquatic ecosystems was investigated. Forty days post hatch (dph) shrimps were exposed to different concentrations of 0.0, 4.3, 6.7, 10.5, 16.4, 25.6 and 40.0 mg/L in a 96 h acute toxicity test; and 0.0, 2.2, 2.8, 3.4, 4.3 and 5.4 mg/L in a 21 d chronic toxicity test. Whole-body AChE activities were determined at the end of the exposure periods by spectrophotometric assay of sample extract; activities were then normalized against protein contents in the samples and expressed in nanomoles of substrate hydrolyzed. Results of both tests showed that AChE activity was concentration-dependent. Mean AChE activities and standard deviations (±SD) for 96 h acute toxicity were 3.6239 (± 0.4185), 3.4157 (± 1.1842), 2.537 (± 1.3989), 2.4253 (± 1.4202), 2.4127 (± 1.9097), 2.0017 (± 1.1080) and 2.316 (± 0.4001) nmol/min/mg protein; while activity levels for 21 d test were 3.6907(± 0.3401), 2.8473 (± 0.713), 2.9134 (± 0.9879), 2.6738 (± 0.7117), 2.3019 (± 0.4464) and 2.1478 (± 0.864) nmol/min/mg protein. Reference basal AChE activity for 40 dph C. nilotica based on the two control groups was estimated as 3.6907 (± 0.3401) nmol/min/mg proteins. The present work provides ecotoxicological basis for the possible use of AChE activity in C. nilotica as a biomarker for monitoring Roundup(®) pollution in freshwater systems. PMID:22699346

  9. Oxidative stress and damage to erythrocytes in patients with chronic obstructive pulmonary disease--changes in ATPase and acetylcholinesterase activity.

    PubMed

    Bukowska, Bożena; Sicińska, Paulina; Pająk, Aneta; Koceva-Chyla, Aneta; Pietras, Tadeusz; Pszczółkowska, Anna; Górski, Paweł; Koter-Michalak, Maria

    2015-12-01

    The study indicates, for the first time, the changes in both ATPase and AChE activities in the membrane of red blood cells of patients diagnosed with COPD. Chronic obstructive pulmonary disease (COPD) is one of the most common and severe lung disorders. We examined the impact of COPD on redox balance and properties of the membrane of red blood cells. The study involved 30 patients with COPD and 18 healthy subjects. An increase in lipid peroxidation products and a decrease in the content of -SH groups in the membrane of red blood cells in patients with COPD were observed. Moreover, an increase in the activity of glutathione peroxidase and a decrease in superoxide dismutase, but not in catalase activity, were found as well. Significant changes in activities of erythrocyte membrane enzymes in COPD patients were also evident demonstrated by a considerably lowered ATPase activity and elevated AChE activity. Changes in the structure and function of red blood cells observed in COPD patients, together with changes in the activity of the key membrane enzymes (ATPases and AChE), can result from the imbalance of redox status of these cells due to extensive oxidative stress induced by COPD disease. PMID:26369587

  10. A novel isopimarane diterpenoid with acetylcholinesterase inhibitory activity from Nepeta sorgerae, an endemic species to the Nemrut Mountain.

    PubMed

    Yilmaz, Anil; Cağlar, Pinar; Dirmenci, Tuncay; Gören, Nezhun; Topçu, Gülaçti

    2012-06-01

    From the dichloromethane extract of Nepeta sorgerae, the isolation and structure elucidation are now reported of a new isopimarane diterpenoid, named sorgerolone, and two known triterpenoids, oleanolic acid and ursolic acid. Antioxidant activity of the extracts and the isolated terpenoids was determined by the DPPH free radical scavenging and lipid peroxidation inhibition (beta-carotene bleaching) methods. Anticholinesterase activity of the extracts and isolates was investigated by Ellman's method against AChE and BChE enzymes. Although the antioxidant activity results were low, the AChE enzyme inhibition of the extracts and terpenoids was very promising. PMID:22816286

  11. Studies on the In Vitro Antiproliferative, Antimicrobial, Antioxidant, and Acetylcholinesterase Inhibition Activities Associated with Chrysanthemum coronarium Essential Oil.

    PubMed

    Bardaweel, Sanaa K; Hudaib, Mohammad M; Tawaha, Khaled A; Bashatwah, Rasha M

    2015-01-01

    The essential oil of the Jordanian Chrysanthemum coronarium L. (garland) was isolated by hydrodistillation from dried flowerheads material. The oil was essayed for its in vitro scavenging activity using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. The results demonstrate that the oil exhibits moderate radical scavenging activity relative to the strong antioxidant ascorbic acid. In addition, cholinesterase inhibitory activity of C. coronarium essential oil was evaluated for the first time. Applying Ellman's colorimetric method, interesting cholinesterase inhibitory activity, which is not dose dependent, was evident for the oil. Furthermore, antimicrobial activities of the oil against both Gram-negative and Gram-positive bacteria were evaluated. While it fails to inhibit Gram-negative bacteria growth, the antibacterial effects demonstrated by the oil were more pronounced against the Gram-positive strains. Moreover, the examined oil was assessed for its in vitro antiproliferative properties where it demonstrated variable activities towards different human cancer cell lines, of which the colon cancer was the most sensitive to the oil treatment. PMID:26290675

  12. Studies on the In Vitro Antiproliferative, Antimicrobial, Antioxidant, and Acetylcholinesterase Inhibition Activities Associated with Chrysanthemum coronarium Essential Oil

    PubMed Central

    Bardaweel, Sanaa K.; Hudaib, Mohammad M.; Tawaha, Khaled A.; Bashatwah, Rasha M.

    2015-01-01

    The essential oil of the Jordanian Chrysanthemum coronarium L. (garland) was isolated by hydrodistillation from dried flowerheads material. The oil was essayed for its in vitro scavenging activity using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. The results demonstrate that the oil exhibits moderate radical scavenging activity relative to the strong antioxidant ascorbic acid. In addition, cholinesterase inhibitory activity of C. coronarium essential oil was evaluated for the first time. Applying Ellman's colorimetric method, interesting cholinesterase inhibitory activity, which is not dose dependent, was evident for the oil. Furthermore, antimicrobial activities of the oil against both Gram-negative and Gram-positive bacteria were evaluated. While it fails to inhibit Gram-negative bacteria growth, the antibacterial effects demonstrated by the oil were more pronounced against the Gram-positive strains. Moreover, the examined oil was assessed for its in vitro antiproliferative properties where it demonstrated variable activities towards different human cancer cell lines, of which the colon cancer was the most sensitive to the oil treatment. PMID:26290675

  13. Impacts of oxidative stress on acetylcholinesterase transcription, and activity in embryos of zebrafish (Danio rerio) following Chlorpyrifos exposure.

    PubMed

    Rodríguez-Fuentes, Gabriela; Rubio-Escalante, Fernando J; Noreña-Barroso, Elsa; Escalante-Herrera, Karla S; Schlenk, Daniel

    2015-01-01

    Organophosphate pesticides cause irreversible inhibition of AChE which leads to neuronal overstimulation and death. Thus, dogma indicates that the target of OP pesticides is AChE, but many authors postulate that these compounds also disturb cellular redox processes, and change the activities of antioxidant enzymes. Interestingly, it has also been reported that oxidative stress plays also a role in the regulation and activity of AChE. The aims of this study were to determine the effects of the antioxidant, vitamin C (VC), the oxidant, t-butyl hydroperoxide (tBOOH) and the organophosphate Chlorpyrifos (CPF), on AChE gene transcription and activity in zebrafish embryos after 72h exposure. In addition, oxidative stress was evaluated by measuring antioxidant enzymes activities and transcription, and quantification of total glutathione. Apical effects on the development of zebrafish embryos were also measured. With the exception of AChE inhibition and enhanced gene expression, limited effects of CPF on oxidative stress and apical endpoints were found at this developmental stage. Addition of VC had little effect on oxidative stress or AChE, but increased pericardial area and heartbeat rate through an unknown mechanism. TBOOH diminished AChE gene expression and activity, and caused oxidative stress when administered alone. However, in combination with CPF, only reductions in AChE activity were observed with no significant changes in oxidative stress suggesting the adverse apical endpoints in the embryos may have been due to AChE inhibition by CPF rather than oxidative stress. These results give additional evidence to support the role of prooxidants in AChE activity and expression. PMID:25937383

  14. Synthesis and structure-activity relationship study of benzofuran-based chalconoids bearing benzylpyridinium moiety as potent acetylcholinesterase inhibitors.

    PubMed

    Mostofi, Manizheh; Mohammadi Ziarani, Ghodsi; Mahdavi, Mohammad; Moradi, Alireza; Nadri, Hamid; Emami, Saeed; Alinezhad, Heshmatollah; Foroumadi, Alireza; Shafiee, Abbas

    2015-10-20

    A series of benzofuran-based chalconoids 6a-v were designed and synthesized as new potential AChE inhibitors. The in vitro assay of synthesized compounds 6a-v showed that most compounds had significant anti-AChE activity at micromolar or sub-micromolar levels. Among the tested compounds, 3-pyridinium derivative 6m bearing N-(2-bromobenzyl) moiety and 7-methoxy substituent on the benzofuran ring exhibited superior activity. This compound with IC₅₀ value of 0.027 μM was as potent as standard drug donepezil. PMID:26363872

  15. Novel multitarget-directed ligands (MTDLs) with acetylcholinesterase (AChE) inhibitory and serotonergic subtype 4 receptor (5-HT4R) agonist activities as potential agents against Alzheimer's disease: the design of donecopride.

    PubMed

    Rochais, Christophe; Lecoutey, Cédric; Gaven, Florence; Giannoni, Patrizia; Hamidouche, Katia; Hedou, Damien; Dubost, Emmanuelle; Genest, David; Yahiaoui, Samir; Freret, Thomas; Bouet, Valentine; Dauphin, François; Sopkova de Oliveira Santos, Jana; Ballandonne, Céline; Corvaisier, Sophie; Malzert-Fréon, Aurélie; Legay, Remi; Boulouard, Michel; Claeysen, Sylvie; Dallemagne, Patrick

    2015-04-01

    In this work, we describe the synthesis and in vitro evaluation of a novel series of multitarget-directed ligands (MTDL) displaying both nanomolar dual-binding site (DBS) acetylcholinesterase inhibitory effects and partial 5-HT4R agonist activity, among which donecopride was selected for further in vivo evaluations in mice. The latter displayed procognitive and antiamnesic effects and enhanced sAPPα release, accounting for a potential symptomatic and disease-modifying therapeutic benefit in the treatment of Alzheimer's disease. PMID:25793650

  16. Fluorescence properties and sequestration of peripheral anionic site specific ligands in bile acid hosts: Effect on acetylcholinesterase inhibition activity.

    PubMed

    Islam, Mullah Muhaiminul; Aguan, Kripamoy; Mitra, Sivaprasad

    2016-05-01

    The increase in fluorescence intensity of model acetyl cholinesterase (AChE) inhibitors like propidium iodide (PI) and ethidium bromide (EB) is due to sequestration of the probes in primary micellar aggregates of bile acid (BA) host medium with moderate binding affinity of ca. 10(2)-10(3)M(-1). Multiple regression analysis of solvent dependent fluorescence behavior of PI indicates the decrease in total nonradiative decay rate due to partial shielding of the probe from hydrogen bond donation ability of the aqueous medium in bile acid bound fraction. Both PI and EB affects AChE activity through mixed inhibition and consistent with one site binding model; however, PI (IC50=20±1μM) shows greater inhibition in comparison with EB (IC50=40±3μM) possibly due to stronger interaction with enzyme active site. The potency of AChE inhibition for both the compounds is drastically reduced in the presence of bile acid due to the formation of BA-inhibitor complex and subsequent reduction of active inhibitor fraction in the medium. Although the inhibition mechanism still remains the same, the course of catalytic reaction critically depends on equilibrium binding among several species present in the solution; particularly at low inhibitor concentration. All the kinetic parameters for enzyme inhibition reaction are nicely correlated with the association constant for BA-inhibitor complex formation. PMID:26974580

  17. Design, synthesis, acetylcholinesterase inhibition and larvicidal activity of girgensohnine analogs on Aedes aegypti, vector of dengue fever.

    PubMed

    Carreño Otero, Aurora L; Vargas Méndez, Leonor Y; Duque L, Jonny E; Kouznetsov, Vladimir V

    2014-05-01

    Girgensohnine alkaloid was used as a natural model in the design and generation of new alkaloid-like α-aminonitrile series that was completed by the use of SSA-catalyzed Strecker reaction between commercial and inexpensive substituted benzaldehydes, piperidine (pyrrolidine, morpholine and N-methylpiperazine) and acetone cyanohydrin. Calculated ADMETox parameters of the designed analogs revealed their good pharmacokinetic profiles indicating lipophilic characteristics. In vitro AChE enzyme test showed that obtained α-aminonitriles could be considered as AChEIs with micromolar IC50 values ranging from 42.0 to 478.0 μM (10.3-124.0 μg/mL). Among this series, the best AChE inhibitor was the pyrrolidine α-aminonitrile 3 (IC50 = 42 μM), followed by the piperidine α-aminonitriles 2 and 6 (IC50 = 45 μM and IC50 = 51 μM, respectively), and the compound 7 (IC50 = 51 μM). In vivo insecticidal activity of more active AChEIs against Aedes aegypti larvae was also performed showing a good larvicidal activity at concentrations less than 140 ppm, highlighting products 2 and 7 that could serve as lead compounds to develop new potent and selective insecticides. PMID:24704612

  18. Nitric oxide associated with iNOS expression inhibits acetylcholinesterase activity and induces memory impairment during acute hypobaric hypoxia.

    PubMed

    Udayabanu, M; Kumaran, D; Nair, R Unnikrishnan; Srinivas, P; Bhagat, Neeta; Aneja, R; Katyal, Anju

    2008-09-16

    The mechanisms responsible for cholinergic dysfunction associated learning and memory impairment during hypoxia are not well-understood. However it is known that inflammatory mediators like inducible nitric oxide synthase (iNOS) hamper the functions of cholinergic neurons. In this present experiment we made an effort to study the iNOS expression mediated retrograde and anterograde memory impairment in Balb/c mice following acute hypobaric hypoxia (at an altitude of 23,000ft for 6h) using elevated plus maze and passive avoidance step-through tasks. Our results demonstrated that hypoxia transiently impairs the retrograde memory without affecting the anterograde memory functions, accompanied with a substantial rise in iNOS expression and nitric oxide levels in cerebral cortex on days 2 and 3 post hypoxia. Treatment with aminoguanidine (iNOS inhibitor ), resulted in down-regulation of the iNOS expression, attenuation of the surge of nitric oxide (NO) in cerebral cortex and reversal of retrograde memory impairment due to hypoxia. Moreover the reduced AChE activity and elevated lipid peroxidation in cerebral cortex were evident during post hypoxia re-oxygenation period, which was not observed in the hippocampus. Additionally, NO donor spermine NONOate could inhibit the AChE activity in brain homogenates in a concentration-dependent manner, which further substantiate that nitric oxide produced during post hypoxia re-oxygenation, primarily contributes to the observed inhibition of cortical AChE activity. Based on these experiments we hypothesize that the NO burst as a result of iNOS upregulation during hypoxia interrupts the memory consolidation by altering the cholinergic functions. PMID:18639532

  19. Secretion of acetylcholinesterase and butyrylcholinesterase from the guinea-pig isolated ileum.

    PubMed Central

    Appleyard, M. E.; Smith, A. D.

    1989-01-01

    1. Strips of longitudinal muscle from guinea-pig ileum, retaining Auerbach's plexus, were superfused with oxygenated Krebs solution. Addition of 50 mM KCl led to a pronounced Ca2+-dependent increase in the activities of both acetylcholinesterase and non-specific cholinesterase (butyrylcholinesterase) in the perfusate but with no change in lactate dehydrogenase activity. 2. No release of acetylcholinesterase, either spontaneous or K+-evoked was observed in tissue freed of the nerve plexus, although release of butyrylcholinesterase still occurred. 3. Carbachol induced a marked Ca2+-dependent increase in the release of acetylcholinesterase but had no effect on the release of butyrylcholinesterase or lactate dehydrogenase. This carbachol-evoked increase in acetylcholinesterase release was blocked by hexamethonium but not by atropine. 4. Four readily soluble molecular forms of acetylcholinesterase and three soluble molecular forms of butyrylcholinesterase were present in innervated longitudinal muscle strips, but insignificant amounts of acetylcholinesterase were detected in denervated strips of muscle. Only one of the four molecular forms of acetylcholinesterase was recovered in the perfusates. 5. It is concluded that acetylcholinesterase is secreted from the nerves of Auerbach's plexus in response to depolarizing stimuli or to nicotinic cholinergic stimulation, while butyrylcholinesterase is secreted from non-neural elements, possibly the longitudinal muscle cells, of guinea-pig ileum in response to a depolarizing stimulus. Images Figure 5 Figure 6 PMID:2758227

  20. Novel assay utilizing fluorochrome-tagged physostigmine (Ph-F) to in situ detect active acetylcholinesterase (AChE) induced during apoptosis.

    PubMed

    Huang, Xuan; Lee, Brian; Johnson, Gary; Naleway, John; Guzikowski, Anthony; Dai, Wei; Darzynkiewicz, Zbigniew

    2005-01-01

    It was recently reported that acetylcholinesterase (AChE) is expressed in cells undergoing apoptosis and that its presence is essential for assembly of the apoptosome and subsequent caspase-9 activation. To obtain a marker of active AChE that could assay this enzyme in live intact cells and be applicable to fluorescence microscopy and cytometry, the fluorescein-tagged physostigmine (Ph-F), high affinity ligand (inhibitor) reactive with the active center of AChE, was constructed and tested for its ability to in situ label AChE and measure its induction during apoptosis. Ph-F inhibited cholinesterase activity in vitro (IC50 = 10(-6) and 5 x 10(-6) M for equine butyrylcholinesterase and human erythrocyte AChE, respectively) and was a selective marker of cells and structures that were AChE-positive. Thus, exposure of mouse bone marrow cells to Ph-F resulted in the exclusive labeling of megakaryocytes, and of the diaphragm muscle, preferential labeling of the nerve-muscle junctions (end-plates). During apoptosis of carcinoma HeLa cells and leukemic HL-60 or Jurkat cells triggered either by the DNA topoisomerase 1 inhibitor topotecan (TPT) or by oxidative stress (H2O2), the cells become reactive with Ph-F. Their Ph-F derived fluorescence was measured by flow and laser scanning cytometry. The appearance of Ph-F binding sites during apoptosis was preceded by the loss of mitochondrial potential, was concurrent with the presence of activated caspases, and was followed by loss of membrane integrity. At a very early stage of apoptosis, when nucleolar segregation was apparent, the Ph-F binding sites were distinctly localized within the nucleolus and at later stages of apoptosis in the cytoplasm. During apoptosis triggered by TPT, Ph-F binding was preferentially induced in S-phase cells. Our data on megakaryocytes and end-plates indicate that Ph-F reacts with active sites of AChE, and can be used to reveal the presence of this enzyme in live cells and possibly to study its

  1. Brain acetylcholinesterase activity recovery following acute methyl parathion intoxication in two feral rodent species: comparison to laboratory rodents

    SciTech Connect

    Roberts, D.K.; Silvey, N.J.; Bailey, E.M. Jr.

    1988-07-01

    Widespread use of organophosphorus insecticides (OPs) has produced both acute and chronic intoxication among nontarget organisms. Most such studies have included fish and birds as opposed to mammals. However, numerous OP toxicity studies have been conducted on laboratory rodents creating a temptation to apply this data to feral rodents. Chronic OP exposure has been reported to produce cholinergic adaptation which in turn lowers mortality rates following a subsequent acute anticholinesterase exposure. The relevance that these laboratory rodent studies have on feral rodents is subject to debate. Field studies involving OP exposure among nontarget feral mammals have produced contradictory results. Increased mortality as a result of repeated OP application has been reported. This observation may be of considerable importance to nontarget feral rodent populations due to the repetitive nature of OP application protocols. The ability of feral rodents to recover brain AChE activity (BAA) between OP application intervals undoubtedly promotes their survival. This study investigated and compared BAA recovery following acute oral methyl parathion intoxication among 2 feral rodent species and among 2 common laboratory rodent species.

  2. Gaia Payload Module Testing and Analysis Activities

    NASA Astrophysics Data System (ADS)

    Soula, Laurent

    2012-07-01

    The Gaia objective is to produce a very accurate catalogue of 1 billion of sky objects in our galaxy and beyond. ASTRIUM’s extensive experience on silicon carbide (SiC) instruments has helped developing the latest-generation payload module. It integrates the most sensitive and stable telescopes ever made, mounted on a SiC torus structure supported by three bipods. This payload module has been tested in June 2011 by ASTRIUM at INTESPACE facilities in Toulouse. To conduct the sine qualification tests and support the data analyses in real-time, advanced tools have been used. Most of them have been developed in a previous ESA R&D project [1] “DYNamics: AssessMent and Improvement of TEst Data (DYNAMITED)” and implemented in a DynaWorks® environment. Mass Operator calculation, to evaluate the payload module interface loads from measured accelerations, or automatic correlation through a criterion based on FRF from tests or predictions, are part of these tools. Testing such a structure also revealed some piloting difficulties due to a quite low and varying damping of the structure and a strong coupling with the shaker. To take into account such phenomena in the correlation work, enhanced simulations have also been performed considering multi-points phased excitations. These analyses demonstrate the payload module qualification status and allow derivate a more representative model to be used in further coupled system activities.

  3. Laboratory and Simulated Field Bioassays to Evaluate Larvicidal Activity of Pinus densiflora Hydrodistillate, Its Constituents and Structurally Related Compounds against Aedes albopictus, Aedes aegypti and Culex pipiens pallens in Relation to Their Inhibitory Effects on Acetylcholinesterase Activity.

    PubMed

    Lee, Dong Chan; Ahn, Young-Joon

    2013-01-01

    The toxicity of Pinus densiflora (red pine) hydrodistillate, its 19 constituents and 28 structurally related compounds against early third-instar larvae of Aedes albopictus (Ae. albopictus), Aedes aegypti (Ae. aegypti) and Culex pipiens palles (Cx. p. pallens) was examined using direct-contact bioassays. The efficacy of active compounds was further evaluated in semi-field bioassays using field-collected larval Cx. p. pallens. Results were compared with those of two synthetic larvicides, temephos and fenthion. In laboratory bioassays, Pinus densiflora hydrodistillate was found to have 24 h LC50 values of 20.33, 21.01 and 22.36 mg/L against larval Ae. albopictus, Ae. aegypti and Cx. p. pallens respectively. Among the identified compounds, thymol, δ-3-carene and (+)-limonene exhibited the highest toxicity against all three mosquito species. These active compounds were found to be nearly equally effective in field trials as well. In vitro bioassays were conducted to examine the acetylcholinesterase (AChE) inhibitory activity of 10 selected compounds. Results showed that there is a noticeable correlation between larvicidal activity and AChE inhibitory activity. In light of global efforts to find alternatives for currently used insecticides against disease vector mosquitoes, Pinus densiflora hydrodistillate and its constituents merit further research as potential mosquito larvicides. PMID:26464387

  4. Laboratory and Simulated Field Bioassays to Evaluate Larvicidal Activity of Pinus densiflora Hydrodistillate, Its Constituents and Structurally Related Compounds against Aedes albopictus, Aedes aegypti and Culex pipiens pallens in Relation to Their Inhibitory Effects on Acetylcholinesterase Activity

    PubMed Central

    Lee, Dong Chan; Ahn, Young-Joon

    2013-01-01

    The toxicity of Pinus densiflora (red pine) hydrodistillate, its 19 constituents and 28 structurally related compounds against early third-instar larvae of Aedes albopictus (Ae. albopictus), Aedes aegypti (Ae. aegypti) and Culex pipiens palles (Cx. p. pallens) was examined using direct-contact bioassays. The efficacy of active compounds was further evaluated in semi-field bioassays using field-collected larval Cx. p. pallens. Results were compared with those of two synthetic larvicides, temephos and fenthion. In laboratory bioassays, Pinus densiflora hydrodistillate was found to have 24 h LC50 values of 20.33, 21.01 and 22.36 mg/L against larval Ae. albopictus, Ae. aegypti and Cx. p. pallens respectively. Among the identified compounds, thymol, δ-3-carene and (+)-limonene exhibited the highest toxicity against all three mosquito species. These active compounds were found to be nearly equally effective in field trials as well. In vitro bioassays were conducted to examine the acetylcholinesterase (AChE) inhibitory activity of 10 selected compounds. Results showed that there is a noticeable correlation between larvicidal activity and AChE inhibitory activity. In light of global efforts to find alternatives for currently used insecticides against disease vector mosquitoes, Pinus densiflora hydrodistillate and its constituents merit further research as potential mosquito larvicides. PMID:26464387

  5. Design, synthesis and preliminary structure-activity relationship investigation of nitrogen-containing chalcone derivatives as acetylcholinesterase and butyrylcholinesterase inhibitors: a further study based on Flavokawain B Mannich base derivatives.

    PubMed

    Liu, Haoran; Fan, Haoqun; Gao, Xiaohui; Huang, Xueqing; Liu, Xianjun; Liu, Linbo; Zhou, Chao; Tang, Jingjing; Wang, Qiuan; Liu, Wukun

    2016-08-01

    In order to study the structure-activity relationship of Flavokawain B Mannich-based derivatives as acetylcholinesterase (AChE) inhibitors in our recent investigation, 20 new nitrogen-containing chalcone derivatives (4 a-8d) were designed, synthesized, and evaluated for AChE inhibitory activity in vitro. The results suggested that amino alkyl side chain of chalcone dramatically influenced the inhibitory activity against AChE. Among them, compound 6c revealed the strongest AChE inhibitory activity (IC50 value: 0.85 μmol/L) and the highest selectivity against AChE over BuChE (ratio: 35.79). Enzyme kinetic study showed that the inhibition mechanism of compound 6c against AChE was a mixed-type inhibition. The molecular docking assay showed that this compound can both bind with the catalytic site and the peripheral site of AChE. PMID:26186269

  6. Inhibitors of acetylcholinesterase and butyrylcholinesterase meet immunity.

    PubMed

    Pohanka, Miroslav

    2014-01-01

    Acetylcholinesterase (AChE) inhibitors are widely used for the symptomatic treatment of Alzheimer's disease and other dementias. More recent use is for myasthenia gravis. Many of these inhibitors interact with the second known cholinesterase, butyrylcholinesterase (BChE). Further, evidence shows that acetylcholine plays a role in suppression of cytokine release through a "cholinergic anti-inflammatory pathway" which raises questions about the role of these inhibitors in the immune system. This review covers research and discussion of the role of the inhibitors in modulating the immune response using as examples the commonly available drugs, donepezil, galantamine, huperzine, neostigmine and pyridostigmine. Major attention is given to the cholinergic anti-inflammatory pathway, a well-described link between the central nervous system and terminal effector cells in the immune system. PMID:24893223

  7. Inhibitors of Acetylcholinesterase and Butyrylcholinesterase Meet Immunity

    PubMed Central

    Pohanka, Miroslav

    2014-01-01

    Acetylcholinesterase (AChE) inhibitors are widely used for the symptomatic treatment of Alzheimer’s disease and other dementias. More recent use is for myasthenia gravis. Many of these inhibitors interact with the second known cholinesterase, butyrylcholinesterase (BChE). Further, evidence shows that acetylcholine plays a role in suppression of cytokine release through a “cholinergic anti-inflammatory pathway” which raises questions about the role of these inhibitors in the immune system. This review covers research and discussion of the role of the inhibitors in modulating the immune response using as examples the commonly available drugs, donepezil, galantamine, huperzine, neostigmine and pyridostigmine. Major attention is given to the cholinergic anti-inflammatory pathway, a well-described link between the central nervous system and terminal effector cells in the immune system. PMID:24893223

  8. Genetic factors potentially reducing fitness cost of organophosphate-insensitive acetylcholinesterase(s) in Rhipicephalus (Boophilus) microplus (Acari: Ixodidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Acaricidal activity of organophosphate (OP) and carbamate acaricides is believed to result from inhibition of acetylcholinesterase (AChE). Previous studies in Rhipicephalus (Boophilus) microplus demonstrated the presence of three presumptive AChE genes (BmAChEs). Biochemical characterization of re...

  9. World Energy Projection System Plus (WEPS ): Global Activity Module

    EIA Publications

    2013-01-01

    World Energy Projection System Plus Model Documentation: Global Activity Module Documents the objectives, analytical approach, and development of the World Energy Projection Plus (WEPS ) Global Activity Module (GAM) used to develop the International Energy Outlook for 2013 (IEO2013). The report catalogues and describes the module assumptions, computations, methodology, parameter estimation techniques, and mainframe source code.

  10. Involvement of protein kinase C and IP3-mediated Ca2+ release in activity modulation by paraoxon in snail neurons.

    PubMed

    Vatanparast, Jafar; Janahmadi, Mahyar; Asgari, Ali Reza

    2007-10-01

    We have previously reported that paraoxon, an organophosphate compound, at submicromolar concentrations effectively suppresses Ca2+ action potentials and modulates the activity of snail neurons. This effect was unrelated to acetylcholinesterase inhibition but was found to involve the direct or indirect modulation of ion channels [Vatanparast, J., Janahmadi, M., Asgari, A.R., Sepehri, H., Haeri-Rohani, A., 2006a. Paraoxon suppresses Ca2+ action potential and afterhyperpolarization in snail neurons: Relevance to the hyperexcitability induction. Brain Res. 1083 (1), 110-117]. In the present work, the interaction of paraoxon with protein kinase C (PKC) and inositol 1,4,5-trisphosphate (IP3)-mediated Ca2+ release, on the modulation of Ca2+ action potentials and neuronal activity was investigated. Phorbol 12, 13 dibutyrate (PdBu), the activator of PKC, suppressed afterhyperpolarization and increased the activity of snail neurons without any significant effect on the Ca2+ action potential duration. Pretreatment with PKC activator attenuated the suppressing effect of paraoxon on the duration of Ca2+ action potentials. Staurosporine, a selective blocker of PKC, did not block the effect of paraoxon on Ca2+ action potential suppression and hyperexcitability induction. Our findings did not support the involvement PKC in the paraoxon induced Ca2+ action potential suppression and neuronal activity modulation, although activation of this protein kinase could attenuate some effects of paraoxon. Pretreatment with 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate hydrochloride (TMB-8), an antagonist of IP3-mediated Ca2+ release, abolished the secondary silencing effect of paraoxon, which is observed after primary paraoxon-induced hyperexcitability. It was concluded that slow activation of intracellular cascades by paraoxon could induce an IP3 mediated Ca2+ release from intracellular stores and participate to its secondary silencing effect by mechanisms dependent on intracellular

  11. Effect of local acetylcholinesterase inhibition on sweat rate in humans

    NASA Technical Reports Server (NTRS)

    Shibasaki, M.; Crandall, C. G.

    2001-01-01

    ACh is the neurotransmitter responsible for increasing sweat rate (SR) in humans. Because ACh is rapidly hydrolyzed by acetylcholinesterase (AChE), it is possible that AChE contributes to the modulation of SR. Thus the primary purpose of this project was to identify whether AChE around human sweat glands is capable of modulating SR during local application of various concentrations of ACh in vivo, as well as during a heat stress. In seven subjects, two microdialysis probes were placed in the intradermal space of the forearm. One probe was perfused with the AChE inhibitor neostigmine (10 microM); the adjacent membrane was perfused with the vehicle (Ringer solution). SR over both membranes was monitored via capacitance hygrometry during microdialysis administration of various concentrations of ACh (1 x 10(-7)-2 M) and during whole body heating. SR was significantly greater at the neostigmine-treated site than at the control site during administration of lower concentrations of ACh (1 x 10(-7)-1 x 10(-3) M, P < 0.05), but not during administration of higher concentrations of ACh (1 x 10(-2)-2 M, P > 0.05). Moreover, the core temperature threshold for the onset of sweating at the neostigmine-treated site was significantly reduced relative to that at the control site. However, no differences in SR were observed between sites after 35 min of whole body heating. These results suggest that AChE is capable of modulating SR when ACh concentrations are low to moderate (i.e., when sudomotor activity is low) but is less effective in governing SR after SR has increased substantially.

  12. Raman spectroscopic analysis of whole blood acetylcholinesterase

    NASA Astrophysics Data System (ADS)

    Wilcox, Phillip G.; Kang, Jin U.

    2014-06-01

    Raman spectra were taken from whole sheep's blood with varying levels of acetylcholinesterase (AChE) inhibition using 229 and 532 nm laser excitation wavelengths. AChE levels were inhibited using the organophosphates malathion, paraoxon-ethyl, and octamethyldiphosphoramide and confirmed using the Ellman method. This AChE activity level was investigated with the Raman spectra and analyzed using a partial least squares calibration and cross validation to determine if the AChE activity could be predicted from the Raman spectrum. Correlation scores of 0.78 and 0.26 between the measured and predicted AChE activity were observed using 229 and 532 nm excitation, respectively. A estimate limit of detection was found to be approximately 0.01 ΔA/min.

  13. Effects of Sequential Applications of Bassa 50EC (Fenobucarb) and Vitashield 40EC (Chlorpyrifos ethyl) on Acetylcholinesterase Activity in Climbing Perch (Anabas testudineus) Cultured in Rice Fields in the Mekong Delta, Vietnam.

    PubMed

    Tam, Nguyen Thanh; Berg, Håkan; Laureus, Jenny; Cong, Nguyen Van; Tedengren, Michael

    2016-07-01

    This study assesses the effects of sequential applications of the insecticides Bassa 50EC (fenobucarb-F) and Vitashield 40EC (chlorpyrifos ethyl-CPF), sprayed at concentrations used by rice farmers in the Mekong Delta, on the brain acetylcholinesterase (AChE) in climbing perch fingerlings. After spraying the pesticides on the rice fields, the water concentrations of both insecticides decreased below the detection levels within 3 days. The sequential applications caused significant inhibition on the brain AChE activity in the exposed fish. The inhibition by F was quicker, but less prolonged, than for CPF. The inhibition levels caused by the sequential applications were lower than those caused by only CPF and by a mixture of CPF and F. The results indicate that sequential applications of pesticides could have a negative impact on aquatic organisms and fish yields, with implication for the aquatic biodiversity, local people's livelihood and the aquaculture industry in the Mekong Delta. PMID:27075585

  14. Vobasinyl-iboga bisindole alkaloids, potent acetylcholinesterase inhibitors from Tabernaemontana divaricata root.

    PubMed

    Ingkaninan, Kornkanok; Changwijit, Kanokwan; Suwanborirux, Khanit

    2006-06-01

    The roots of the Thai medicinal plant, Tabernaemontana divaricata (L.) R. Br. ex Roem. & Schult., were investigated for their content of acetylcholinesterase inhibitors. Bioassay-guided fractionation using the Ellman colorimetric method led to the isolation of two bisindole alkaloids, 19,20-dihydrotabernamine and 19,20-dihydroervahanine A. The compounds showed higher inhibitory activity on acetylcholinesterase in comparison with galanthamine, a well-known acetylcholinesterase inhibitor. The inhibitory activity of 19,20-dihydroervahanine A was proved to be specific, reversible and competitive. During the separation process, two inactive bisindole alkaloids, conodurine and tabernaelegantine A, were also isolated. The data suggest that the substitutions at the carbons 11', 12' and 16' might affect the acetylcholinesterase inhibitory activity. PMID:16734986

  15. Revision of the DELFIC Particle Activity Module

    SciTech Connect

    Hooper, David A; Jodoin, Vincent J

    2010-09-01

    The Defense Land Fallout Interpretive Code (DELFIC) was originally released in 1968 as a tool for modeling fallout patterns and for predicting exposure rates. Despite the continual advancement of knowledge of fission yields, decay behavior of fission products, and biological dosimetry, the decay data and logic of DELFIC have remained mostly unchanged since inception. Additionally, previous code revisions caused a loss of conservation of radioactive nuclides. In this report, a new revision of the decay database and the Particle Activity Module is introduced and explained. The database upgrades discussed are replacement of the fission yields with ENDF/B-VII data as formatted in the Oak Ridge Isotope Generation (ORIGEN) code, revised decay constants, revised exposure rate multipliers, revised decay modes and branching ratios, and revised boiling point data. Included decay logic upgrades represent a correction of a flaw in the treatment of the fission yields, extension of the logic to include more complex decay modes, conservation of nuclides (including stable nuclides) at all times, and conversion of key variables to double precision for nuclide conservation. Finally, recommended future work is discussed with an emphasis on completion of the overall radiation physics upgrade, particularly for dosimetry, induced activity, decay of the actinides, and fractionation.

  16. Rotavirus infection activates the UPR but modulates its activity

    PubMed Central

    2011-01-01

    Background Rotaviruses are known to modulate the innate antiviral defense response driven by IFN. The purpose of this study was to identify changes in the cellular proteome in response to rotavirus infection in the context of the IFN response. We also sought to identify proteins outside the IFN induction and signaling pathway that were modulated by rotavirus infection. Methods 2D-DIGE and image analysis were used to identify cellular proteins that changed in levels of expression in response to rotavirus infection, IFN treatment, or IFN treatment prior to infection. Immunofluorescence microscopy was used to determine the subcellular localization of proteins associated with the unfolded protein response (UPR). Results The data show changes in the levels of multiple proteins associated with cellular stress in infected cells, including levels of ER chaperones GRP78 and GRP94. Further investigations showed that GRP78, GRP94 and other proteins with roles in the ER-initiated UPR including PERK, CHOP and GADD34, were localized to viroplasms in infected cells. Conclusions Together the results suggest rotavirus infection activates the UPR, but modulates its effects by sequestering sensor, transcription factor, and effector proteins in viroplasms. The data consequently also suggest that viroplasms may directly or indirectly play a fundamental role in regulating signaling pathways associated with cellular defense responses. PMID:21774819

  17. Geranylphenazinediol, an acetylcholinesterase inhibitor produced by a Streptomyces species.

    PubMed

    Ohlendorf, Birgit; Schulz, Dirk; Erhard, Arlette; Nagel, Kerstin; Imhoff, Johannes F

    2012-07-27

    Geranylphenazinediol (1), a new phenazine natural product, was produced by the Streptomyces sp. strain LB173, which was isolated from a marine sediment sample. The structure was established by analysis of NMR and MS data. 1 inhibited the enzyme acetylcholinesterase in the low micromolar range and showed weak antibacterial activity. In order to get a more detailed picture of the activity profile of 1, its inhibitory potential was compared to that of related structures. PMID:22775474

  18. Synthetic conversion of ACAT inhibitor to acetylcholinesterase inhibitor.

    PubMed

    Obata, R; Sunazuka, T; Otoguro, K; Tomoda, H; Harigaya, Y; Omura, S

    2000-06-19

    Natural product acyl-CoA:cholesterol acyltransferase (ACAT) inhibitor pyripyropene A was synthetically converted to acetylcholinesterase (AChE) inhibitor via heterolitic cleavage of the 2-pyrone ring, followed by gamma-acylation/cyclization with several aroyl chlorides. The 4-pyridyl analogue selectively showed AChE inhibitory activity (IC50 7.9 microM) and no ACAT inhibitory activity IC50 = >1000 microM. PMID:10890154

  19. The acetylcholinesterase gene of Anopheles stephensi.

    PubMed

    Hall, L M; Malcolm, C A

    1991-02-01

    1. The acetylcholinesterase (AChE) gene from the important malaria vector Anopheles stephensi has been isolated by homology to the Drosophila acetylcholinesterase gene. 2. The complete sequence and intron-exon organization has been determined. The encoded protein has 69% identity to Drosophila AChE and 38 and 36% identity to Torpedo AChE and human butyrylcholinesterase, respectively. PMID:1901515

  20. New Acetylcholinesterase Inhibitors for Alzheimer's Disease

    PubMed Central

    Mehta, Mona; Adem, Abdu; Sabbagh, Marwan

    2012-01-01

    Acetylcholinesterase (AChE) remains a highly viable target for the symptomatic improvement in Alzheimer's disease (AD) because cholinergic deficit is a consistent and early finding in AD. The treatment approach of inhibiting peripheral AchE for myasthenia gravis had effectively proven that AchE inhibition was a reachable therapeutic target. Subsequently tacrine, donepezil, rivastigmine, and galantamine were developed and approved for the symptomatic treatment of AD. Since then, multiple cholinesterase inhibitors (ChEI) continue to be developed. These include newer ChEIs, naturally derived ChEIs, hybrids, and synthetic analogues. In this paper, we summarize the different types of ChEIs in development and their respective mechanisms of actions. This pharmacological approach continues to be active with many promising compounds. PMID:22216416

  1. On-site analysis of acetylcholinesterase and butyrylcholinesterase activity with the ChE check mobile test kit-Determination of reference values and their relevance for diagnosis of exposure to organophosphorus compounds.

    PubMed

    Worek, Franz; Schilha, Martina; Neumaier, Katharina; Aurbek, Nadine; Wille, Timo; Thiermann, Horst; Kehe, Kai

    2016-05-13

    Poisoning by organophosphorus compounds (OP) still poses a major medical challenge. Diagnosis of clinical signs of OP poisoning is still the most important parameter for the initiation of specific treatment. However, in case of unspecific signs and of delayed onset of cholinergic crisis a rapid, reliable and on-site analysis of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity would be of great value. Recently the ChE check mobile, a CE-certified ready to use kit for the determination of whole blood AChE and BChE activities, was developed. Here, we evaluated whole blood AChE and BChE reference values with samples taken from 181 male and 61 female volunteers and analyzed them on-site with the ChE check mobile test kit. The analysis of the data revealed a large inter-individual variability (BChE>AChE), only a small sex difference for AChE but a significant difference for BChE activities. The now available normal range values enable an evaluation of determined AChE and BChE activities in case of suspected exposure to OP nerve agents and pesticides. However, the large inter-individual variability of AChE and BChE activities calls for the determination of pre-exposure values in specific subpopulations in order to enable the diagnosis of low-level OP exposure. PMID:27033775

  2. Space station group activities habitability module study

    NASA Technical Reports Server (NTRS)

    Nixon, David

    1986-01-01

    This study explores and analyzes architectural design approaches for the interior of the Space Station Habitability Module (originally defined as Habitability Module 1 in Space Station Reference Configuration Decription, JSC-19989, August 1984). In the Research Phase, architectural program and habitability design guidelines are specified. In the Schematic Design Phase, a range of alternative concepts is described and illustrated with drawings, scale-model photographs and design analysis evaluations. Recommendations are presented on the internal architectural, configuration of the Space Station Habitability Module for such functions as the wardroom, galley, exercise facility, library and station control work station. The models show full design configurations for on-orbit performance.

  3. The Effect of Parathion on Red Blood Cell Acetylcholinesterase in the Wistar Rat

    PubMed Central

    Bunya, Naofumi; Sawamoto, Keigo; Benoit, Hanif

    2016-01-01

    Organophosphorus (OP) pesticide poisoning is a significant problem worldwide. Research into new antidotes for these acetylcholinesterase inhibitors, and even optimal doses for current therapies, is hindered by a lack of standardized animal models. In this study, we sought to characterize the effects of the OP pesticide parathion on acetylcholinesterase in a Wistar rat model that included comprehensive medical care. Methods. Male Wistar rats were intubated and mechanically ventilated and then poisoned with between 20 mg/kg and 60 mg/kg of intravenous parathion. Upon developing signs of poisoning, the rats were treated with standard critical care, including atropine, pralidoxime chloride, and midazolam, for up to 48 hours. Acetylcholinesterase activity was determined serially for up to 8 days after poisoning. Results. At all doses of parathion, maximal depression of acetylcholinesterase occurred at 3 hours after poisoning. Acetylcholinesterase recovered to nearly 50% of baseline activity by day 4 in the 20 mg/kg cohort and by day 5 in the 40 and 60 mg/kg cohorts. At day 8, most rats' acetylcholinesterase had recovered to roughly 70% of baseline. These data should be useful in developing rodent models of acute OP pesticide poisoning. PMID:27418928

  4. The Effect of Parathion on Red Blood Cell Acetylcholinesterase in the Wistar Rat.

    PubMed

    Bunya, Naofumi; Sawamoto, Keigo; Benoit, Hanif; Bird, Steven B

    2016-01-01

    Organophosphorus (OP) pesticide poisoning is a significant problem worldwide. Research into new antidotes for these acetylcholinesterase inhibitors, and even optimal doses for current therapies, is hindered by a lack of standardized animal models. In this study, we sought to characterize the effects of the OP pesticide parathion on acetylcholinesterase in a Wistar rat model that included comprehensive medical care. Methods. Male Wistar rats were intubated and mechanically ventilated and then poisoned with between 20 mg/kg and 60 mg/kg of intravenous parathion. Upon developing signs of poisoning, the rats were treated with standard critical care, including atropine, pralidoxime chloride, and midazolam, for up to 48 hours. Acetylcholinesterase activity was determined serially for up to 8 days after poisoning. Results. At all doses of parathion, maximal depression of acetylcholinesterase occurred at 3 hours after poisoning. Acetylcholinesterase recovered to nearly 50% of baseline activity by day 4 in the 20 mg/kg cohort and by day 5 in the 40 and 60 mg/kg cohorts. At day 8, most rats' acetylcholinesterase had recovered to roughly 70% of baseline. These data should be useful in developing rodent models of acute OP pesticide poisoning. PMID:27418928

  5. Biochemical effects of glyphosate based herbicide, Excel Mera 71 on enzyme activities of acetylcholinesterase (AChE), lipid peroxidation (LPO), catalase (CAT), glutathione-S-transferase (GST) and protein content on teleostean fishes.

    PubMed

    Samanta, Palas; Pal, Sandipan; Mukherjee, Aloke Kumar; Ghosh, Apurba Ratan

    2014-09-01

    Effects of glyphosate based herbicide, Excel Mera 71 at a dose of 17.20mg/l on enzyme activities of acetylcholinesterase (AChE), lipid peroxidation (LPO), catalase (CAT), glutathione-S-transferase (GST) and protein content were measured in different tissues of two Indian air-breathing teleosts, Anabas testudineus (Bloch) and Heteropneustes fossilis (Bloch) during an exposure period of 30 days under laboratory condition. AChE activity was significantly increased in all the investigated tissues of both fish species and maximum elevation was observed in brain of H. fossilis, while spinal cord of A. testudineus showed minimum increment. Fishes showed significant increase LPO levels in all the tissues; highest was observed in gill of A. testudineus but lowest LPO level was observed in muscle of H. fossilis. CAT was also enhanced in both the fishes, while GST activity in liver diminished substantially and minimum was observed in liver of A. testudineus. Total protein content showed decreased value in all the tissues, maximum reduction was observed in liver and minimum in brain of A. testudineus and H. fossilis respectively. The results indicated that Excel Mera 71 caused serious alterations in the enzyme activities resulting into severe deterioration of fish health; so, AChE, LPO, CAT and GST can be used as suitable indicators of herbicidal toxicity. PMID:24927388

  6. Acetylcholinesterase in zebrafish embryos as a tool to identify neurotoxic effects in sediments.

    PubMed

    Kais, Britta; Stengel, Daniel; Batel, Annika; Braunbeck, Thomas

    2015-11-01

    In order to clarify the suitability of zebrafish (Danio rerio) embryos for the detection of neurotoxic compounds, the acetylcholinesterase assay was adapted and validated with a series of priority pollutants listed as relevant for the European water policy (Aroclor 1254, 2,3-benzofuran, bisphenol A, chlorpyrifos, paraoxon-methyl, quinoline, and methyl mercury chloride) as well as acetonic extracts from three sediments of known contamination. The acute toxicities of the model substances and the sediment extracts were determined by means of the fish embryo test as specified in OECD TG 236, and concentrations as low as the effective concentration at 10% inhibition (EC10) were used as the highest test concentration in the acetylcholinesterase test in order to avoid nonspecific systemic effects mimicking neurotoxicity. Among the model compounds, only the known acetylcholinesterase inhibitors paraoxon-methyl and chlorpyrifos produced a strong inhibition to about 20 and 33%, respectively, of the negative controls. For the sediment extracts, a reduction of acetylcholinesterase activity to about 60% could only be shown for the Vering Canal sediment extracts; this could be correlated to high contents of acetylcholinesterase-inhibiting polycyclic aromatic hydrocarbons (PAHs) as identified by chemical analyses. Co-incubation of the Vering Canal sediment extracts with chlorpyrifos at EC10 concentrations each did not significantly increase the inhibitory effect of chlorpyrifos, indicating that the mode of action of acetylcholinesterase inhibition by the sediment-borne PAHs is different to that of the typical acetylcholinesterase blocker chlorpyrifos. Overall, the study documents that zebrafish embryos represent a suitable model not only to reveal acetylcholinesterase inhibition, but also to investigate various modes of neurotoxic action. PMID:25567057

  7. TMPyP4, a Stabilizer of Nucleic Acid Secondary Structure, Is a Novel Acetylcholinesterase Inhibitor

    PubMed Central

    Fujiwara, Nana; Mazzola, Michael; Cai, Elizabeth; Wang, Meng; Cave, John W.

    2015-01-01

    The porphyrin compound, TMPyP4 (5,10,15,20-Tetrakis-(N-methyl-4-pyridyl)porphine), is widely used as a photosensitizer and a modulator of nucleic acid secondary structure stability. Our group recently showed in cultured cells and forebrain slice cultures that this compound can also down regulate expression of Tyrosine hydroxylase (Th), which encodes the rate-limiting enzyme in catecholamine biosynthesis, by stabilizing DNA secondary structures in the Th proximal promoter. The current study sought to establish whether treatment with TMPyP4 could modify mouse Th expression levels in vivo. Intraperitoneal administration of low TMPyP4 doses (10mg/kg), similar to those used for photosensitization, did not significantly reduce Th transcript levels in several catecholaminergic regions. Administration of a high dose (40 mg/kg), similar to those used for tumor xenograph reduction, unexpectedly induced flaccid paralysis in an age and sex-dependent manner. In vitro analyses revealed that TMPyP4, but not putative metabolites, inhibited Acetylcholinesterase activity and pre-treatment of TMPyP4 with Hemeoxygenase-2 (HO-2) rescued Acetylcholinesterase function. Age-dependent differences in HO-2 expression levels may account for some of the variable in vivo effects of high TMPyP4 doses. Together, these studies indicate that only low doses of TMPyP4, such as those typically used for photosensitization, are well tolerated in vivo. Thus, despite its widespread use in vitro, TMPyP4 is not ideal for modifying neuronal gene expression in vivo by manipulating nucleic acid secondary structure stability, which highlights the need to identify more clinically suitable compounds that can modulate nucleic acid secondary structure and gene expression. PMID:26402367

  8. PICALM modulates autophagy activity and tau accumulation

    PubMed Central

    Moreau, Kevin; Fleming, Angeleen; Imarisio, Sara; Lopez Ramirez, Ana; Mercer, Jacob L.; Jimenez-Sanchez, Maria; Bento, Carla F.; Puri, Claudia; Zavodszky, Eszter; Siddiqi, Farah; Lavau, Catherine P.; Betton, Maureen; O’Kane, Cahir J.; Wechsler, Daniel S.; Rubinsztein, David C.

    2014-01-01

    Genome-wide association studies have identified several loci associated with Alzheimer’s disease (AD), including proteins involved in endocytic trafficking such as PICALM/CALM (phosphatidylinositol binding clathrin assembly protein). It is unclear how these loci may contribute to AD pathology. Here we show that CALM modulates autophagy and alters clearance of tau, a protein which is a known autophagy substrate and which is causatively linked to AD, both in vitro and in vivo. Furthermore, altered CALM expression exacerbates tau-mediated toxicity in zebrafish transgenic models. CALM influences autophagy by regulating the endocytosis of SNAREs, such as VAMP2, VAMP3 and VAMP8, which have diverse effects on different stages of the autophagy pathway, from autophagosome formation to autophagosome degradation. This study suggests that the AD genetic risk factor CALM modulates autophagy, and this may affect disease in a number of ways including modulation of tau turnover. PMID:25241929

  9. Basic Activated Sludge. Training Module 2.115.2.77.

    ERIC Educational Resources Information Center

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with operation of activated sludge wastewater treatment plants. Included are objectives, instructor guides, student handouts, and transparency masters. This is the first of a three module series and considers definition of terms, design…

  10. Intermediate Activated Sludge. Training Module 2.116.3.77.

    ERIC Educational Resources Information Center

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with operation of activated sludge wastewater treatment plants. Included are objectives, instructor guides, student handouts and transparency masters. This is the second level of a three module series and considers aeration devices,…

  11. Infant Smiling during Social Interaction: Arousal Modulation or Activation Indicator?

    ERIC Educational Resources Information Center

    Ewy, Richard

    In a study of infant smiling, 20 mother-infant dyads were videotaped in normal face-to-face interaction when the infants were 9 and 14 weeks of age. Videotapes were used to determine which of two classes of smiling behavior models, either arousal modulation or activation indicator, was most supported by empirical data. Arousal modulation models…

  12. Advanced Activated Sludge. Training Module 2.117.4.77.

    ERIC Educational Resources Information Center

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with operation of activated sludge wastewater treatment plants. Included are objectives, instructor guides, student handouts and transparency masters. This is the third level of a three module series and considers design and operation…

  13. Intercultural Orientation Activities for International ESL Students: 50 Module Lessons.

    ERIC Educational Resources Information Center

    Villarreal, Linda

    Fifty modules are presented for increasing the cultural and linguistic fluency of English-as-a-Second-Language (ESL) students by integrating cultural awareness activities with language practice. The modules are intended for international students at an intermediate language level; they can, however, be used or adapted for beginning or advanced…

  14. Musical hallucinations treated with acetylcholinesterase inhibitors.

    PubMed

    Blom, Jan Dirk; Coebergh, Jan Adriaan F; Lauw, René; Sommer, Iris E C

    2015-01-01

    Musical hallucinations are relatively rare auditory percepts which, due to their intrusive nature and the accompanying fear of impending mental decline, tend to cause significant distress and impairment. Although their etiology and pathophysiology appear to be heterogeneous and no evidence-based treatment methods are available, case reports indicate that acetylcholinesterase inhibitors may yield positive results in patients with comorbid hearing loss. We present two female patients (aged 76 and 78 years) both of whom suffered from hearing impairment and practically incessant musical hallucinations. Both patients were successfully treated with the acetylcholinesterase inhibitor rivastigmine. Based on these two case descriptions and an overview of studies describing the use of acetylcholinesterase inhibitors in similar patients, we discuss possible mechanisms and propose further research on the use of acetylcholinesterase inhibitors for musical hallucinations experienced in concordance with hearing loss. PMID:25904872

  15. Musical Hallucinations Treated with Acetylcholinesterase Inhibitors

    PubMed Central

    Blom, Jan Dirk; Coebergh, Jan Adriaan F.; Lauw, René; Sommer, Iris E. C.

    2015-01-01

    Musical hallucinations are relatively rare auditory percepts which, due to their intrusive nature and the accompanying fear of impending mental decline, tend to cause significant distress and impairment. Although their etiology and pathophysiology appear to be heterogeneous and no evidence-based treatment methods are available, case reports indicate that acetylcholinesterase inhibitors may yield positive results in patients with comorbid hearing loss. We present two female patients (aged 76 and 78 years) both of whom suffered from hearing impairment and practically incessant musical hallucinations. Both patients were successfully treated with the acetylcholinesterase inhibitor rivastigmine. Based on these two case descriptions and an overview of studies describing the use of acetylcholinesterase inhibitors in similar patients, we discuss possible mechanisms and propose further research on the use of acetylcholinesterase inhibitors for musical hallucinations experienced in concordance with hearing loss. PMID:25904872

  16. Seasonal variation in antioxidative responses and acetylcholinesterase activity in Perna viridis in eastern oceanic and western estuarine waters of Hong Kong

    NASA Astrophysics Data System (ADS)

    Lau, P. S.; Wong, H. L.; Garrigues, Ph.

    2004-10-01

    A year-round study was conducted to assess the seasonal variations and potential influence of the riverine discharge from the Pearl River on biomarker responses in Hong Kong waters. A suite of biomarkers including antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), the lipid peroxidation product malondialdehyde (MDA), a Phase II detoxification enzyme glutathione-S-transferase (GST) and the neural transmitter enzyme acetylcholinesterase (AChE) in the green mussel, Perna viridis, were monitored from three coastal sites, Port Shelter, Tung Chung and Tai O, stretching from the east to the west of Hong Kong. Despite of the seasonal variations, the total protein profiles suggested that mussels from the three sites had a growth cycle that was in phase with each other. This implied that intrinsic variation between sites due to a different phase of growth was minimal. Seasonal variations of the biomarker responses in the mussels were found to be significant (Tukey multiple comparison test, p<0.05) with a summer minimum and winter maximum. On top of seasonal variations, the western site, Tai O, was further subjected to the reduced salinity effect of the Pearl River discharge in the summer wet season. This was demonstrated by the significant July minimum in all the biomarker responses at Tai O in relation to the extreme low salinity of 8‰. Mussels from the western site also revealed a higher oxidative stress than those from the eastern side throughout the year (Tukey multiple comparison test, p<0.05), which could be caused by chemical pollutants from the Pearl River discharge. ANOVAs of the year-round dataset suggested that size was a minor factor in affecting the biomarker responses. Gill tissues of the mussels were more advantageous for biomarker studies or monitoring because their protein levels were less sensitive to seasonal variations and they yielded a higher protein normalized biomarker response than the whole body tissues. This increases their

  17. Role of acetylcholinesterase inhibitors in the metabolism of amyloid precursor protein.

    PubMed

    Pakaski, M; Kasa, P

    2003-06-01

    Potentiation of central cholinergic activity has been proposed as a therapeutic approach for improving the cognitive function in patients with Alzheimer's disease (AD). Increasing the acetylcholine concentration in the brain by modulating acetylcholine-sterase (AChE) activity is among the most promising therapeutic strategies. Efforts to treat the underlying pathology based on the modulation of amyloid precursor protein (APP) processing in order to decrease the accumulation of beta-amyloid are also very important. Alterations in APP metabolism have recently been proposed to play a key role in the long-lasting effects of AChE inhibitors. This review surveys recent data from in vivo and in vitro studies that have contributed to our understanding of the role of AChE inhibitors in APP processing. The regulatory mechanisms relating to the muscarinic agonist effect, protein kinase C activation and mitogen-activated protein kinase phosphorylation, involving the alpha-secretase or the 5 -UTR region of the APP gene, are also discussed. Further work is warranted to elucidate the exact roles in APP metabolism of the AChE inhibitors used in AD therapy at present. PMID:12769797

  18. A Second Class of Acetylcholinesterase-Deficient Mutants of the Nematode CAENORHABDITIS ELEGANS

    PubMed Central

    Culotti, Joseph G.; Von Ehrenstein, Gunter; Culotti, Marilyn R.; Russell, Richard L.

    1981-01-01

    In Johnson et al. (1981), the Caenorhabditis elegans mutant strain PR1000, homozygous for the ace-1 mutation p1000, is shown to be deficient in the class A subset of acetylcholinesterases, which comprises approximately one-half of the total C. elegans acetylcholinesterase activity. Beginning with this strain, we have isolated 487 new behavioral and morphological mutant strains. Two of these, independently derived, lack approximately 98% of the wild-type acetylcholinesterase activity and share the same specific uncoordinated phenotype; both move forward in a slow and uncoordinated manner, and when mechanically stimulated to induce reversal, both hypercontract and become temporarily paralyzed. In addition to the ace-1 mutation, both strains also harbor recessive mutations in the same newly identified gene, ace-2, which maps to chromosome I and is therefore not linked to ace-1. Gene dosage experiments suggest that ace-2 is a structural gene for the remaining class B acetylcholinesterases, which are not affected by ace-1.—The uncoordinated phenotype of the newly isolated, doubly mutant strains depends on both the ace-1 and ace-2 mutations; homozygosity for either mutation alone produces normally coordinated animals. This result implies functional overlap of the acetylcholinesterases controlled by ace-1 and ace-2, perhaps at common synapses. Consistent with this, light microscopic histochemical staining of permeabilized whole mounts indicates some areas of possible spatial overlap of these acetylcholinesterases (nerve ring, longitudinal nerve cords). In addition, there is at least one area where only ace-2-controlled acetylcholinesterase activity appears (pharyngeo-intestinal valve). PMID:7274655

  19. Wireless multi-level terahertz amplitude modulator using active metamaterial-based spatial light modulation.

    PubMed

    Rout, Saroj; Sonkusale, Sameer

    2016-06-27

    The ever increasing demand for bandwidth in wireless communication systems will inevitably lead to the extension of operating frequencies toward the terahertz (THz) band known as the 'THz gap'. Towards closing this gap, we present a multi-level amplitude shift keying (ASK) terahertz wireless communication system using terahertz spatial light modulators (SLM) instead of traditional voltage mode modulation, achieving higher spectral efficiency for high speed communication. The fundamental principle behind this higher efficiency is the conversion of a noisy voltage domain signal to a noise-free binary spatial pattern for effective amplitude modulation of a free-space THz carrier wave. Spatial modulation is achieved using an an active metamaterial array embedded with pseudomorphic high-electron mobility (pHEMT) designed in a consumer-grade galium-arsenide (GaAs) integrated circuit process which enables electronic control of its THz transmissivity. Each array is assembled as individually controllable tiles for transmissive terahertz spatial modulation. Using the experimental data from our metamaterial based modulator, we show that a four-level ASK digital communication system has two orders of magnitude improvement in symbol error rate (SER) for a degradation of 20 dB in transmit signal-to-noise ratio (SNR) using spatial light modulation compared to voltage controlled modulation. PMID:27410614

  20. Acetylcholinesterase inhibitors and Gulf War illnesses

    PubMed Central

    Golomb, Beatrice Alexandra

    2008-01-01

    Increasing evidence suggests excess illness in Persian Gulf War veterans (GWV) can be explained in part by exposure of GWV to organophosphate and carbamate acetylcholinesterase inhibitors (AChEis), including pyridostigmine bromide (PB), pesticides, and nerve agents. Evidence germane to the relation of AChEis to illness in GWV was assessed. Many epidemiological studies reported a link between AChEi exposure and chronic symptoms in GWV. The link is buttressed by a dose–response relation of PB pill number to chronic symptoms in GWV and by a relation between avidity of AChEi clearance and illness, based on genotypes, concentrations, and activity levels of enzymes that detoxify AChEis. Triangulating evidence derives from studies linking occupational exposure to AChEis to chronic health symptoms that mirror those of ill GWV. Illness is again linked to lower activity of AChEi detoxifying enzymes and genotypes conferring less-avid AChEi detoxification. AChEi exposure satisfies Hill's presumptive criteria for causality, suggesting this exposure may be causally linked to excess health problems in GWV. PMID:18332428

  1. Oxidative desorption of thiocholine assembled on core-shell Fe3O4/AuNPs magnetic nanocomposites for highly sensitive determination of acetylcholinesterase activity: an exposure biomarker of organophosphates.

    PubMed

    Du, Dan; Tao, Yuan; Zhang, Weiying; Liu, Deli; Li, Haibing

    2011-06-15

    Acetylcholinesterase (AChE) activity is a well established biomarker for biomonitoring of exposures to organophosphates (OPs) pesticides and chemical nerve agents. In this work, we described a novel electrochemical oxidative desorption-process of thiocholine, the product of enzymatic reaction, for rapid and highly sensitive determination of AChE activity in human serum. This principle is based on self-assembling of produced thiocholine onto core-shell Fe(3)O(4)/Au nanoparticles (Fe(3)O(4)/AuNPs) magnetic nanocomposites and its oxidation at electrode surface. Fe(3)O(4) magnetic core is not only used for magnetic separation from sample solutions, but also carrying more AuNPs due to its large surface-to-volume ratio. The core-shell Fe(3)O(4)/AuNPs nanocomposites were characterized by UV-Vis spectroscopy, field-emission scanning electron microscopy (FE-SEM) and electrochemical measurements. A linear relationship was obtained between the AChE activity and its concentration from 0.05 to 5.0 mU mL(-1) with a detection limit of 0.02 mU mL(-1). The method showed good results for characterization of AChE spiked human serum and detection of OP exposures from 0.05 to 20 nM, with detection limit of 0.02 nM. This new oxidative desorption assay thus provides a sensitive and quantitative tool for biomonitoring of the exposure to OP pesticides and nerve agents. PMID:21514816

  2. Nonlinear active wave modulation approach for microdamage detection

    NASA Astrophysics Data System (ADS)

    Wu, Hwai-Chung; Warnemuende, Kraig

    2001-07-01

    Several nondestructive testing methods can be used to estimate the extents of damage in a concrete structure. Pulse-velocity and amplitude attenuation, are very common in nondestructive ultrasonic evaluation. Velocity of propagation is not very sensitive to the degrees of damage unless a great deal of micro-damage having evolving into localized macro-damage. Amplitude attenuation is potentially more sensitive than pulse-velocity. However, this method depends strongly on the coupling conditions between transducers and concrete, hence unreliable. A new active modulation approach, Nonlinear Active Wave Modulation Spectroscopy, is adopted in our study. In this procedure, a probe wave will be passed through the system in a similar fashion to regular acoustics. Simultaneously, a second, low frequency modulating wave will be applied to the system to effectively change the size and stiffness of flaws microscopically and cyclically, thereby causing the frequency modulation to change cyclically as well. The resulting amplified modulations will be correlated to the extents of damage with the effect that even slight damage should become quantifiable. This study unveils the potential of nonlinear frequency analysis methods for micro-damage detection and evaluation using actively modulated acoustic signals. This method can interrogate materials exaggerating the nonlinearly that exists due to microcracking and deterioration.

  3. Modulation of Brain Activity during Phonological Familiarization

    ERIC Educational Resources Information Center

    Majerus, S.; Van der Linden, M.; Collette, F.; Laureys, S.; Poncelet, M.; Degueldre, C.; Delfiore, G.; Luxen, A.; Salmon, E.

    2005-01-01

    We measured brain activity in 12 adults for the repetition of auditorily presented words and nonwords, before and after repeated exposure to their phonological form. The nonword phoneme combinations were either of high (HF) or low (LF) phonotactic frequency. After familiarization, we observed, for both word and nonword conditions, decreased…

  4. Targeting Acetylcholinesterase to Membrane Rafts

    PubMed Central

    Xie, Heidi Q.; Liang, Dong; Leung, K. Wing; Chen, Vicky P.; Zhu, Kevin Y.; Chan, Wallace K. B.; Choi, Roy C. Y.; Massoulié, Jean; Tsim, Karl W. K.

    2010-01-01

    In the mammalian brain, acetylcholinesterase (AChE) is anchored in cell membranes by a transmembrane protein PRiMA (proline-rich membrane anchor). We present evidence that at least part of the PRiMA-linked AChE is integrated in membrane microdomains called rafts. A significant proportion of PRiMA-linked AChE tetramers from rat brain was recovered in raft fractions; this proportion was markedly higher at low rather than at high concentrations of cold Triton X-100. The detergent-resistant fraction increased during brain development. In NG108-15 neuroblastoma cells transfected with cDNAs encoding AChET and PRiMA, PRiMA-linked G4 AChE was found in membrane rafts and showed the same sensitivity to cold Triton X-100 extraction as in the brain. The association of PRiMA-linked AChE with rafts was weaker than that of glycosylphosphatidylinositol-anchored G2 AChE or G4 QN-HC-linked AChE. It was found to depend on the presence of a cholesterol-binding motif, called CRAC (cholesterol recognition/interaction amino acid consensus), located at the junction of transmembrane and cytoplasmic domains of both PRiMA I and II isoforms. The cytoplasmic domain of PRiMA, which differs between PRiMA I and PRiMA II, appeared to play some role in stabilizing the raft localization of G4 AChE, because the Triton X-100-resistant fraction was smaller with the shorter PRiMA II isoform than that with the longer PRiMA I isoform. PMID:20147288

  5. [Peptidergic modulation of the hippocampus synaptic activity].

    PubMed

    Skrebitskiĭ, V G; Kondratenko, R V; Povarov, I S; Dereviagin, V I

    2011-11-01

    Effects of two newly synthesized nootropic and anxiolytic dipeptides: Noopept and Selank on inhibitory synaptic transmission in hippocampal CA1 pyramidal cells were investigated using patch-clamp technique in whole-cell configuration. Bath application of Noopept (1 microM) or Selank (2 microM) significantly increased the frequency of spike-dependent spontaneous m1PSCs, whereas spike-independent mlPSCs remained unchanged. It was suggested that both peptides mediated their effect sue to activation of inhibitory interneurons terminating on CA1 pyramidal cells. Results of current clamp recording of inhibitory interneurons residing in stratum radiatum confirmed this suggestion, at least for Noonent. PMID:22390072

  6. Infraslow EEG activity modulates cortical excitability in postanoxic encephalopathy

    PubMed Central

    Tjepkema-Cloostermans, Marleen C.; Hofmeijer, Jeannette

    2015-01-01

    Infraslow activity represents an important component of physiological and pathological brain function. We study infraslow activity (<0.1 Hz) in 41 patients with postanoxic coma after cardiac arrest, including the relationship between infraslow activity and EEG power in the 3–30 Hz range, using continuous full-band scalp EEG. In all patients, infraslow activity (0.015–0.06 Hz) was present, irrespective of neurological outcome or EEG activity in the conventional frequency bands. In two patients, low-amplitude (10–30 μV) infraslow activity was present while the EEG showed no rhythmic activity above 0.5 Hz. In 13/15 patients with a good outcome and 20/26 patients with a poor one, EEG power in the 3–30 Hz frequency range was correlated with the phase of infraslow activity, quantified by the modulation index. In 9/14 patients with burst-suppression with identical bursts, bursts appeared in clusters, phase-locked to the infraslow oscillations. This is substantiated by a simulation of burst-suppression in a minimal computational model. Infraslow activity is preserved in postanoxic encephalopathy and modulates cortical excitability. The strongest modulation is observed in patients with severe postanoxic encephalopathy and burst-suppression with identical bursts. PMID:25695645

  7. Epithelial sodium channel modulates platelet collagen activation.

    PubMed

    Cerecedo, Doris; Martínez-Vieyra, Ivette; Alonso-Rangel, Lea; Benítez-Cardoza, Claudia; Ortega, Arturo

    2014-03-01

    Activated platelets adhere to the exposed subendothelial extracellular matrix and undergo a rapid cytoskeletal rearrangement resulting in shape change and release of their intracellular dense and alpha granule contents to avoid hemorrhage. A central step in this process is the elevation of the intracellular Ca(2+) concentration through its release from intracellular stores and on throughout its influx from the extracellular space. The Epithelial sodium channel (ENaC) is a highly selective Na(+) channel involved in mechanosensation, nociception, fluid volume homeostasis, and control of arterial blood pressure. The present study describes the expression, distribution, and participation of ENaC in platelet migration and granule secretion using pharmacological inhibition with amiloride. Our biochemical and confocal analysis in suspended and adhered platelets suggests that ENaC is associated with Intermediate filaments (IF) and with Dystrophin-associated proteins (DAP) via α-syntrophin and β-dystroglycan. Migration assays, quantification of soluble P-selectin, and serotonin release suggest that ENaC is dispensable for migration and alpha and dense granule secretion, whereas Na(+) influx through this channel is fundamental for platelet collagen activation. PMID:24679405

  8. Role of acetylcholinesterase in lung cancer

    PubMed Central

    Xi, Hui-Jun; Wu, Ren-Pei; Liu, Jing-Jing; Zhang, Ling-Juan; Li, Zhao-Shen

    2015-01-01

    Acetylcholinesterase (AChE) plays a key role in catalytic hydrolysis of cholinergic neurotransmitters. Intensive research has proven the involvement of this protein in novel functions, such as cell adhesion, differentiation, and proliferation. In addition, several recent studies have indicated that acetylcholinesterase is potentially a marker and regulator of apoptosis. Importantly, AChE is also a promising tumor suppressor. In this review, we briefly summarize the involvement of AChE in apoptosis and cancer, focusing on the role of AChE in lung cancer, as well as the therapeutic consideration of AChE for cancer therapy. PMID:26273392

  9. Muscle metaboreceptor modulation of cutaneous active vasodilation

    NASA Technical Reports Server (NTRS)

    Crandall, C. G.; Stephens, D. P.; Johnson, J. M.

    1998-01-01

    PURPOSE: Isometric handgrip exercise in hyperthermia has been shown to reduce cutaneous vascular conductance (CVC) by inhibiting the cutaneous active vasodilator system. METHODS: To identify whether this response was initiated by muscle metaboreceptors, in seven subjects two 3-min bouts of isometric handgrip exercise in hyperthermia were performed, followed by 2 min of postexercise ischemia (PEI). An index of forearm skin blood flow (laser-Doppler flowmetry) was measured on the contralateral arm at an unblocked site and at a site at which adrenergic vasoconstrictor function was blocked via bretylium iontophoresis to reveal active cutaneous vasodilator function unambiguously. Sweat rate was measured via capacitance hygrometry, CVC was indexed from the ratio of skin blood flow to mean arterial pressure and was expressed as a percentage of maximal CVC at that site. In normothermia, neither isometric exercise nor PEI affected CVC (P > 0.05). RESULTS: The first bout of isometric handgrip exercise in hyperthermia reduced CVC at control sites and this reduction persisted through PEI (pre-exercise: 59.8 +/- 5.4, exercise: 49.8 +/- 4.9, PEI: 49.7 +/- 5.3% of maximum; both P < 0.05), whereas there were no significant changes in CVC at the bretylium treated sites. The succeeding bout of isometric exercise in hyperthermia significantly reduced CVC at both untreated (pre-exercise: 59.0 +/- 4.8, exercise: 47.3 +/- 4.0, PEI: 50.1 +/- 4.1% of maximum; both P < 0.05) and bretylium treated sites (pre-exercise: 61.4 +/- 7.3, exercise: 50.6 +/- 5.1, PEI: 53.9 +/- 6.0% of maximum, both P < 0.05). At both sites, CVC during PEI was lower than during the pre-exercise period (P < 0.05). Sweat rate rose significantly during both bouts of isometric exercise and remained elevated during PEI. CONCLUSIONS: These data suggest that the reduction in CVC during isometric exercise in hyperthermia, including the inhibition of the active vasodilator system, is primarily mediated by muscle

  10. Phosphorylation Modulates Catalytic Activity of Mycobacterial Sirtuins

    PubMed Central

    Yadav, Ghanshyam S.; Ravala, Sandeep K.; Malhotra, Neha; Chakraborti, Pradip K.

    2016-01-01

    Sirtuins are NAD+-dependent deacetylases involved in the regulation of diverse cellular processes and are conserved throughout phylogeny. Here we report about in vitro transphosphorylation of the only NAD+-dependent deacetylase (mDAC) present in the genome of Mycobacterium tuberculosis by eukaryotic-type Ser/Thr kinases, particularly PknA. The phosphorylated mDAC displayed decreased deacetylase activity compared to its unphosphorylated counterpart. Mass-spectrometric study identified seven phosphosites in mDAC; however, mutational analysis highlighted major contribution of Thr-214 for phosphorylation of the protein. In concordance to this observation, variants of mDAC substituting Thr-214 with either Ala (phospho-ablated) or Glu (phosphomimic) exhibited significantly reduced deacetylase activity suggesting phosphorylation mediated control of enzymatic activity. To assess the role of phosphorylation towards functionality of mDAC, we opted for a sirtuin knock-out strain of Escherichia coli (Δdac), where interference of endogenous mycobacterial kinases could be excluded. The Δdac strain in nutrient deprived acetate medium exhibited compromised growth and complementation with mDAC reversed this phenotype. The phospho-ablated or phosphomimic variant, on the other hand, was unable to restore the functionality of mDAC indicating the role of phosphorylation per se in the process. We further over-expressed mDAC or mDAC-T214A as His-tagged protein in M. smegmatis, where endogenous eukaryotic-type Ser/Thr kinases are present. Anti-phosphothreonine antibody recognized both mDAC and mDAC-T214A proteins in western blotting. However, the extent of phosphorylation as adjudged by scanning the band intensity, was significantly low in the mutant protein (mDAC-T214A) compared to that of the wild-type (mDAC). Furthermore, expression of PknA in the mDAC complemented Δdac strain was able to phosphorylate M. tuberculosis sirtuin. The growth profile of this culture in acetate medium was

  11. Total Cellular RNA Modulates Protein Activity.

    PubMed

    Majumder, Subhabrata; DeMott, Christopher M; Reverdatto, Sergey; Burz, David S; Shekhtman, Alexander

    2016-08-16

    RNA constitutes up to 20% of a cell's dry weight, corresponding to ∼20 mg/mL. This high concentration of RNA facilitates low-affinity protein-RNA quinary interactions, which may play an important role in facilitating and regulating biological processes. In the yeast Pichia pastoris, the level of ubiquitin-RNA colocalization increases when cells are grown in the presence of dextrose and methanol instead of methanol as the sole carbon source. Total RNA isolated from cells grown in methanol increases β-galactosidase activity relative to that seen with RNA isolated from cells grown in the presence of dextrose and methanol. Because the total cellular RNA content changes with growth medium, protein-RNA quinary interactions can alter in-cell protein biochemistry and may play an important role in cell adaptation, critical to many physiological and pathological states. PMID:27456029

  12. Anti-Acetylcholinesterase Alkaloids from Annona glabra Leaf.

    PubMed

    Lee, Shoei-Sheng; Wu, Dong-Yi; Tsai, Sheng-Fa; Chen, Chien-Kuang

    2015-06-01

    Bioassay guided fractionation and separation of the EtOH extract of Annona glabra leaf against acetylcholinesterse led to the characterization of 15 alkaloids. Among them, (-)-actinodaphnine (2) and (-)-(6aS,7R)-7-hydroxyactinodaphnine (9) are new aporphines, although (+)-2 and (±)-2 have been found in several plants. Their structures were established by spectroscopic analysis. (-)-Anolobine (5) and (-)-roemeroline (8) showed moderate inhibitory activity against eel acetylcholinesterase with IC50 values of 22.4 and 26.3 μM, respectively. PMID:26197510

  13. Chemoprotective activity of boldine: modulation of drug-metabolizing enzymes.

    PubMed

    Kubínová, R; Machala, M; Minksová, K; Neca, J; Suchý, V

    2001-03-01

    Possible chemoprotective effects of the naturally occurring alkaloid boldine, a major alkaloid of boldo (Peumus boldus Mol.) leaves and bark, including in vitro modulations of drug-metabolizing enzymes in mouse hepatoma Hepa-1 cell line and mouse hepatic microsomes, were investigated. Boldine manifested inhibition activity on hepatic microsomal CYP1A-dependent 7-ethoxyresorufin O-deethylase and CYP3A-dependent testosterone 6 beta-hydroxylase activities and stimulated glutathione S-transferase activity in Hepa-1 cells. In addition to the known antioxidant activity, boldine could decrease the metabolic activation of other xenobiotics including chemical mutagens. PMID:11265593

  14. Staufen Negatively Modulates MicroRNA Activity in Caenorhabditis elegans

    PubMed Central

    Ren, Zhiji; Veksler-Lublinsky, Isana; Morrissey, David; Ambros, Victor

    2016-01-01

    The double-stranded RNA-binding protein Staufen has been implicated in various posttranscriptional gene regulatory processes. Here, we demonstrate that the Caenorhabditis elegans homolog of Staufen, STAU-1, functionally interacts with microRNAs. Loss-of-function mutations of stau-1 significantly suppress phenotypes of let-7 family microRNA mutants, a hypomorphic allele of dicer, and a lsy-6 microRNA partial loss-of-function mutant. Furthermore, STAU-1 modulates the activity of lin-14, a target of lin-4 and let-7 family microRNAs, and this modulation is abolished when the 3′ untranslated region of lin-14 is removed. Deep sequencing of small RNA cDNA libraries reveals no dramatic change in the levels of microRNAs or other small RNA populations between wild-type and stau-1 mutants, with the exception of certain endogenous siRNAs in the WAGO pathway. The modulation of microRNA activity by STAU-1 does not seem to be associated with the previously reported enhanced exogenous RNAi (Eri) phenotype of stau-1 mutants, since eri-1 exhibits the opposite effect on microRNA activity. Altogether, our results suggest that STAU-1 negatively modulates microRNA activity downstream of microRNA biogenesis, possibly by competing with microRNAs for binding on the 3′ untranslated region of target mRNAs. PMID:26921297

  15. Staufen Negatively Modulates MicroRNA Activity in Caenorhabditis elegans.

    PubMed

    Ren, Zhiji; Veksler-Lublinsky, Isana; Morrissey, David; Ambros, Victor

    2016-01-01

    The double-stranded RNA-binding protein Staufen has been implicated in various posttranscriptional gene regulatory processes. Here, we demonstrate that the Caenorhabditis elegans homolog of Staufen, STAU-1, functionally interacts with microRNAs. Loss-of-function mutations of stau-1 significantly suppress phenotypes of let-7 family microRNA mutants, a hypomorphic allele of dicer, and a lsy-6 microRNA partial loss-of-function mutant. Furthermore, STAU-1 modulates the activity of lin-14, a target of lin-4 and let-7 family microRNAs, and this modulation is abolished when the 3' untranslated region of lin-14 is removed. Deep sequencing of small RNA cDNA libraries reveals no dramatic change in the levels of microRNAs or other small RNA populations between wild-type and stau-1 mutants, with the exception of certain endogenous siRNAs in the WAGO pathway. The modulation of microRNA activity by STAU-1 does not seem to be associated with the previously reported enhanced exogenous RNAi (Eri) phenotype of stau-1 mutants, since eri-1 exhibits the opposite effect on microRNA activity. Altogether, our results suggest that STAU-1 negatively modulates microRNA activity downstream of microRNA biogenesis, possibly by competing with microRNAs for binding on the 3' untranslated region of target mRNAs. PMID:26921297

  16. Hydrophobic Core Flexibility Modulates Enzyme Activity in HIV-1 Protease

    SciTech Connect

    Mittal, Seema; Cai, Yufeng; Nalam, Madhavi N.L.; Bolon, Daniel N.A.; Schiffer, Celia A.

    2012-09-11

    Human immunodeficiency virus Type-1 (HIV-1) protease is crucial for viral maturation and infectivity. Studies of protease dynamics suggest that the rearrangement of the hydrophobic core is essential for enzyme activity. Many mutations in the hydrophobic core are also associated with drug resistance and may modulate the core flexibility. To test the role of flexibility in protease activity, pairs of cysteines were introduced at the interfaces of flexible regions remote from the active site. Disulfide bond formation was confirmed by crystal structures and by alkylation of free cysteines and mass spectrometry. Oxidized and reduced crystal structures of these variants show the overall structure of the protease is retained. However, cross-linking the cysteines led to drastic loss in enzyme activity, which was regained upon reducing the disulfide cross-links. Molecular dynamics simulations showed that altered dynamics propagated throughout the enzyme from the engineered disulfide. Thus, altered flexibility within the hydrophobic core can modulate HIV-1 protease activity, supporting the hypothesis that drug resistant mutations distal from the active site can alter the balance between substrate turnover and inhibitor binding by modulating enzyme activity.

  17. Gallic acid modulates cerebral oxidative stress conditions and activities of enzyme-dependent signaling systems in streptozotocin-treated rats.

    PubMed

    Kade, I J; Rocha, J B T

    2013-04-01

    Redox imbalances and altered signaling processes in the brain are characteristic features of diabetic complications. Hence, the present study therefore sought to evaluate the effect of gallic acid (GA) on disturbed redox systems and activity of neurotransmission signaling dependent enzymes such as sodium pump, purinergic enzymes and acetylcholinesterase in diabetic animal models. We observed that GA markedly improves the antioxidant status of diabetic animals. Furthermore, the diminution of the activity of Na(+)/K(+)-ATPase and increased activities of acetylcholinesterase and the purinergic enzymes associated with diabetes progression were reversed to normalcy with the administration of GA in diabetic animals. Hence, we conclude that GA is a potential candidate in the management of neuronal dysfunction that often accompanied complications associated with diabetic hyperglycemia. PMID:23381106

  18. Anthranilate-Activating Modules from Fungal Nonribosomal Peptide Assembly Lines†

    PubMed Central

    Ames, Brian D.; Walsh, Christopher T.

    2010-01-01

    Fungal natural products containing benzodiazepinone- and quinazolinone-fused ring systems can be assembled by nonribosomal peptide synthetases (NRPS) using the conformationally restricted β-amino acid anthranilate as one of the key building blocks. We validated that the first module of the acetylaszonalenin synthetase of Neosartorya fischeri NRRL 181 activates anthranilate to anthranilyl-AMP. With this as starting point, we then used bioinformatic predictions about fungal adenylation domain selectivities to identify and confirm an anthranilate-activating module in the fumiquinazoline A producer Aspergillus fumigatus Af293 as well as a second anthranilate-activating NRPS in N. fischeri. This establishes an anthranilate adenylation domain code for fungal NRPS and should facilitate detection and cloning of gene clusters for benzodiazepine- and quinazoline-containing polycyclic alkaloids with a wide range of biological activities. PMID:20225828

  19. Tacrine-propargylamine derivatives with improved acetylcholinesterase inhibitory activity and lower hepatotoxicity as a potential lead compound for the treatment of Alzheimer's disease.

    PubMed

    Mao, Fei; Li, Jianheng; Wei, Hui; Huang, Ling; Li, Xingshu

    2015-12-01

    A series of tacrine-propargylamine derivatives were synthesised and evaluated as possible anti-Alzheimer's disease (AD) agents. Among these derivatives, compounds 3a and 3b exhibited superior activities and a favourable balance of AChE and BuChE activities (3a: IC50 values of 51.3 and 77.6 nM; 3b: IC50 values of 11.2 and 83.5 nM). Compounds 3a and 3b also exhibited increased hAChE inhibitory activity compared with tacrine by approximately 5- and 28-fold, respectively, and low neurotoxicity. Importantly, these compounds also had lower hepatotoxicity than tacrine. Based on these results, compounds 3a and 3b could be considered as potential lead compounds for the treatment of AD and other AChE related diseases, such as schizophrenia, glaucoma and myasthenia gravis. PMID:25792506

  20. Alcohol Usage and Abrupt Cessation Modulate Diurnal Activity

    PubMed Central

    Norrell, Stacy; Reyes-Vasquez, Cruz; Burau, Keith; Dafny, Nachum

    2010-01-01

    Alcohol has many effects throughout the body. The effect on circadian rhythms and the correlation of these effects to withdrawal effects of alcohol present interesting findings. By measuring 3 planes of activity of female Sprague-Dawley rats during alcohol usage and continuing study through the first two days following withdrawal of alcohol allow for the observation of a drastic modulation of the circadian pattern of activity. PMID:20615456

  1. Improved Angiostatic Activity of Dasatinib by Modulation with Hydrophobic Chains

    PubMed Central

    2015-01-01

    Dasatinib is an orally active nonselective tyrosine kinase inhibitor used to treat certain types of adult leukemia. By inhibiting PDGFR-β and SFKs in both tumor cells and tumor-associated endothelial cells, dasatinib inhibits tumor growth and angiogenesis. Herein, dasatinib derivatives modified with hydrophobic chains were prepared and evaluated for their in vitro antiproliferative selectivity and their in vivo antiangiogenic activity. For one of the derivatives, modified with a long perfluorinated chain, a significant enhancement in antiangiogenic activity was observed. Combined, these results suggest a possible generic route to modulate the angiostatic activity of drugs. PMID:25815152

  2. World Energy Projection System Plus (WEPS ): Global Activity Module

    EIA Publications

    2016-01-01

    The World Energy Projection System Plus (WEPS ) is a comprehensive, mid?term energy forecasting and policy analysis tool used by EIA. WEPS projects energy supply, demand, and prices by country or region, given assumptions about the state of various economies, international energy markets, and energy policies. The Global Activity Module (GLAM) provides projections of economic driver variables for use by the supply, demand, and conversion modules of WEPS . GLAM’s baseline economic projection contains the economic assumptions used in WEPS to help determine energy demand and supply. GLAM can also provide WEPS with alternative economic assumptions representing a range of uncertainty about economic growth. The resulting economic impacts of such assumptions are inputs to the remaining supply and demand modules of WEPS .

  3. Module Packaging Research and Reliability: Activities and Capabilities

    SciTech Connect

    McMahon, T. J.; delCueto, J.; Glick, S.; Jorgensen, G.; Kempe, M.; Pern, J.; Terwilliger, K.

    2005-11-01

    Our team activities are directed at improving PV module reliability by incorporating new, more effective, and less expensive packaging materials and techniques. New and existing materials or designs are evaluated before and during accelerated environmental exposure for the following properties: (1) Adhesion and cohesion: peel strength and lap shear. (2) Electrical conductivity: surface, bulk, interface and transients. (3) Water vapor transmission: solubility and diffusivity. (4) Accelerated weathering: ultraviolet, temperature, and damp heat tests. (5) Module and cell failure diagnostics: infrared imaging, individual cell shunt characterization, coring. (6) Fabrication improvements: SiOxNy barrier coatings and enhanced wet adhesion. (7) Numerical modeling: Moisture ingress/egress, module and cell performance, and cell-to-frame leakage current. (8) Rheological properties of polymer encapsulant and sheeting materials. Specific examples are described.

  4. Module Design, Materials, and Packaging Research Team: Activities and Capabilities

    SciTech Connect

    McMahon, T. J.; del Cueto, J.; Glick, S.; Jorgensen, G.; Kempe, M.; Kennedy, C.; Pern, J.; Terwilliger, K

    2005-01-01

    Our team activities are directed at improving PV module reliability by incorporating new, more effective, and less expensive packaging materials and techniques. New and existing materials or designs are evaluated before and during accelerated environmental exposure for the following properties: (1) Adhesion and cohesion: peel strength and lap shear. (2) Electrical conductivity: surface, bulk, interface and transients. (3) Water vapor transmission: solubility and diffusivity. (4) Accelerated weathering: ultraviolet, temperature, and damp heat tests. (5) Module and cell failure diagnostics: infrared imaging, individual cell shunt characterization, coring. (6) Fabrication improvements: SiOxNy barrier coatings and enhanced wet adhesion. (7) Numerical modeling: Moisture ingress/egress, module and cell performance, and cell-to-frame leakage current. (8) Rheological properties of polymer encapsulant and sheeting materials. Specific examples will be described.

  5. EFFECTS OF WATER POLLUTANTS AND OTHER CHEMICALS ON FISH ACETYLCHOLINESTERASE (IN VITRO)

    EPA Science Inventory

    Acetylcholinesterase (AChE) preparations from the muscle of the fathead minnow (Pimephales promelas Rafinesque) were treated (in vitro) with 74 chemicals of various classes, many of which are environmental contaminants, to determine their effect upon enzyme activity. A highly inh...

  6. Acetylcholinesterase of Haematobia irritans (Diptera: Muscidae): Baculovirus expression, biochemical properties and organophosphate insensitivity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study reports the baculovirus expression and biochemical characterization of recombinant acetylcholinesterase from Haematobia irritans (L) (rHiAChE) and the effect of the previously described G262A mutation on enzyme activity and sensitivity to selected organophosphates. The rHiAChE was confirm...

  7. Contextual modulation of hippocampal activity during picture naming.

    PubMed

    Llorens, A; Dubarry, A-S; Trébuchon, A; Chauvel, P; Alario, F-X; Liégeois-Chauvel, C

    2016-08-01

    Picture naming is a standard task used to probe language processes in healthy and impaired speakers. It recruits a broad neural network of language related areas, among which the hippocampus is rarely included. However, the hippocampus could play a role during picture naming, subtending, for example, implicit learning of the links between pictured objects and their names. To test this hypothesis, we recorded hippocampal activity during plain picture naming, without memorization requirement; we further assessed whether this activity was modulated by contextual factors such as repetition priming and semantic interference. Local field potentials recorded from intracerebral electrodes implanted in the healthy hippocampi of epileptic patients revealed a specific and reliable pattern of activity, markedly modulated by repetition priming and semantic context. These results indicate that the hippocampus is recruited during picture naming, presumably in relation to implicit learning, with contextual factors promoting differential hippocampal processes, possibly subtended by different sub-circuitries. PMID:27380274

  8. Use of a novel radiometric method to assess the inhibitory effect of donepezil on acetylcholinesterase activity in minimally diluted tissue samples

    PubMed Central

    Kikuchi, Tatsuya; Okamura, Toshimitsu; Arai, Takuya; Obata, Takayuki; Fukushi, Kiyoshi; Irie, Toshiaki; Shiraishi, Tetsuya

    2010-01-01

    Background and purpose: Cholinesterase inhibitors have been widely used for the treatment of patients with dementia. Monitoring of the cholinesterase activity in the blood is used as an indicator of the effect of the cholinesterase inhibitors in the brain. The selective measurement of cholinesterase with low tissue dilution is preferred for accurate monitoring; however, the methods have not been established. Here, we investigated the effect of tissue dilution on the action of cholinesterase inhibitors using a novel radiometric method with selective substrates, N-[14C]methylpiperidin-4-yl acetate ([14C]MP4A) and (R)-N-[14C]methylpiperidin-3-yl butyrate ([14C]MP3B_R), for AChE and butyrylcholinesterase (BChE) respectively. Experimental approach: We investigated the kinetics of hydrolysis of [14C]-MP4A and [14C]-MP3B_R by cholinesterases, and evaluated the selectivity of [14C]MP4A and [14C]MP3B_R for human AChE and BChE, respectively, compared with traditional substrates. Then, IC50 values of cholinesterase inhibitors in minimally diluted and highly diluted tissues were measured with [14C]MP4A and [14C]MP3B_R. Key results: AChE and BChE activities were selectively measured as the first-order hydrolysis rates of [14C]-MP4A and [14C]MP3B_R respectively. The AChE selectivity of [14C]MP4A was an order of magnitude higher than traditional substrates used for the AChE assay. The IC50 values of specific AChE and BChE inhibitors, donepezil and ethopropazine, in 1.2-fold diluted human whole blood were much higher than those in 120-fold diluted blood. In addition, the IC50 values of donepezil in monkey brain were dramatically decreased as the tissue was diluted. Conclusions and implications: This method would effectively monitor the activity of cholinesterase inhibitors used for therapeutics, pesticides and chemical warfare agents. PMID:20401964

  9. Pd(II) complexes of acetylcholinesterase reactivator obidoxime

    PubMed Central

    Stoykova, Silviya; Atanasov, Vasil; Pantcheva, Ivayla; Antonov, Liudmil

    2014-01-01

    The ability of the acetylcholinesterase reactivator obidoxime (H2L2+) to bind palladium(II) cations was evaluated spectrophotometrically at different reaction conditions (pH, reaction time, metal-to-ligand molar ratio). The results showed that immediately after mixing the reagents, pH 7.4, complex species of composition [PdHL]3+ existed predominantly with a value of conditional stability constant lgβ‘=6.52. The reaction was completed within 24 hours affording the formation of species [Pd2L]4+ with significantly increased stability (lgβ‘=9.34). The spectral data suggest that obidoxime coordinates metal(II) ions through the oximate functional groups. The in vitro reactivation assay of paraoxon-inhibited rat brain acetylcholinesterase revealed that the new complex species were much less active than the non-coordinated obidoxime. The lack of reactivation ability could be explained by the considerable stability of complexes in solution as well as by the deprotonation of oxime groups essential for recovery of the enzymatic activity. PMID:26109891

  10. Solar activity and modulation of the cosmic ray intensity

    NASA Technical Reports Server (NTRS)

    Akasofu, S.-I.; Olmsted, C.; Lockwood, J. A.

    1985-01-01

    Since its discovery by Forbush (1954), the 11-year cycle modulation of the cosmic ray intensity has been studied extensively. Bowe and Hatton (1982) obtained a well-behaved transfer function F between the solar activity S and the cosmic ray intensity modulation Io-I. They suggested that the 11-year variation for sunspot cycle 20 can be attributed to the modulating effect of solar flare-induced shocks propagating through the heliosphere. The cosmic ray intensity in the absence of solar activity is denoted by Io, while I denotes the observed intensity. Bowe and Hatton infer that the boundary of the heliosphere is located at a distance of 70-90 AU. Since their conclusion is of great importance in understanding the mechanism of the 11-year modulation, the present investigation is concerned with a repetition of their study for two cycles, taking into account the use of a slightly modified method. The obtained results confirm the conclusions reached by Bowe and Hatton that there is a well-behaved transfer function for solar flares.

  11. Biological activity of a polypeptide modulator of TRPV1 receptor.

    PubMed

    Dyachenko, I A; Andreev, Ya A; Logashina, Yu A; Murashev, A N; Grishin, E V

    2015-11-01

    This paper presents data on the activity of a new APHC2 polypeptide modulator of TRPV1 receptors, which was isolated from the sea anemone Heteractis crispa. It has been shown that APHC2 has an analgesic activity, does not impair normal motor activity, and does not change body temperature of experimental animals, which has a great practical value for design of potent analgesics of a new generation. Further study of the characteristics of binding of the polypeptide to the TRPV1 receptor may show approaches to the development of other antagonists of this receptor that do not influence the body temperature. PMID:26725234

  12. Inhibition of acetylcholinesterase in guppies (Poecilia reticulata) by chlorpyrifos at sublethal concentrations: Methodological aspects

    SciTech Connect

    van der Wel, H.; Welling, W.

    1989-04-01

    Acetylcholinesterase activity is a potential biochemical indicator of toxic stress in fish and a sensitive parameter for testing water for the presence of organophosphates. A number of methodological aspects regarding the determination of the in vivo effect of chlorpyrifos on acetylcholinesterase in guppies have been investigated. It was found that with acetylthiocholine as a substrate, the contribution of pseudocholinesterase to the total cholinesterase activity can be neglected. Protection of acetylcholinesterase of guppies exposed to chlorpyrifos from additional, artifactual in vitro enzyme inhibition during homogenization is necessary. Very low concentrations of acetone in the exposure medium, resulting from dilution of the stock solution of chlorpyrifos in acetone, can result in large decreases in the oxygen content of this medium. This may affect the uptake rate of the toxic compound and, thereby, cholinesterase inhibition. Very low, sublethal concentrations of chlorpyrifos result in high inhibition levels of acetylcholinesterase (80-90%) in guppies within 2 weeks of continuous exposure. Recovery of the enzyme activity occurs after the exposed animals are kept in clean medium for 4 days, but the rate of recovery is considerably lower than the rate of inhibition.

  13. Capsaicin modulates proliferation, migration, and activation of hepatic stellate cells.

    PubMed

    Bitencourt, Shanna; Mesquita, Fernanda; Basso, Bruno; Schmid, Júlia; Ferreira, Gabriela; Rizzo, Lucas; Bauer, Moises; Bartrons, Ramon; Ventura, Francesc; Rosa, Jose Luis; Mannaerts, Inge; van Grunsven, Leo Adrianus; Oliveira, Jarbas

    2014-03-01

    Capsaicin, the active component of chili pepper, has been reported to have antiproliferative and anti-inflammatory effects on a variety of cell lines. In the current study, we aimed to investigate the effects of capsaicin during HSC activation and maintenance. Activated and freshly isolated HSCs were treated with capsaicin. Proliferation was measured by incorporation of EdU. Cell cycle arrest and apoptosis were investigated using flow cytometry. The migratory response to chemotactic stimuli was evaluated by a modified Boyden chamber assay. Activation markers and inflammatory cytokines were determined by qPCR, immunocytochemistry, and flow cytometry. Our results show that capsaicin reduces HSC proliferation, migration, and expression of profibrogenic markers of activated and primary mouse HSCs. In conclusion, the present study shows that capsaicin modulates proliferation, migration, and activation of HSC in vitro. PMID:23955514

  14. Acetylcholinesterase-R increases germ cell apoptosis but enhances sperm motility

    PubMed Central

    Mor, I; Sklan, EH; Podoly, E; Pick, M; Kirschner, M; Yogev, L; Bar-Sheshet Itach, S; Schreiber, L; Geyer, B; Mor, T; Grisaru, D; Soreq, H

    2008-01-01

    Abstract Changes in protein subdomains through alternative splicing often modify protein-protein interactions, altering biological processes. A relevant example is that of the stress-induced up-regulation of the acetylcholinesterase (AChE-R) splice variant, a common response in various tissues. In germ cells of male transgenic TgR mice, AChE-R excess associates with reduced sperm differentiation and sperm counts. To explore the mechanism(s) by which AChE-R up-regulation affects spermatogenesis, we identified AChE-R's protein partners through a yeast two-hybrid screen. In meiotic spermatocytes from TgR mice, we detected AChE-R interaction with the scaffold protein RACK1 and elevated apoptosis. This correlated with reduced scavenging by RACK1 of the pro-apoptotic TAp73, an outcome compatible with the increased apoptosis. In contrast, at later stages in sperm development, AChE-R's interaction with the glycolytic enzyme enolase-α elevates enolase activity. In transfected cells, enforced AChE-R excess increased glucose uptake and adenosine tri-phosphate (ATP) levels. Correspondingly, TgR sperm cells display elevated ATP levels, mitochondrial hyperactivity and increased motility. In human donors' sperm, we found direct association of sperm motility with AChE-R expression. Interchanging interactions with RACK1 and enolase-α may hence enable AChE-R to affect both sperm differentiation and function by participating in independent cellular pathways. PMID:18194455

  15. Neuronal modulation of calcium channel activity in cultured rat astrocytes

    SciTech Connect

    Corvalan, V.; Cole, R.; De Vellis, J.; Hagiwara, Susumu )

    1990-06-01

    The patch-clamp technique was used to study whether cocultivation of neurons and astrocytes modulates the expression of calcium channel activity in astrocytes. Whole-cell patch-clamp recordings from rat brain astrocytes cocultured with rat embryonic neurons revealed two types of voltage-dependent inward currents carried by Ca{sup 2+} and blocked by either Cd{sup 2+} or Co{sup 2+} that otherwise were not detected in purified astrocytes. This expression of calcium channel activity in astrocytes was neuron dependent and was not observed when astrocytes were cocultured with purified oligodendrocytes.

  16. Sphingosine, a modulator of human translesion DNA polymerase activity.

    PubMed

    Kamath-Loeb, Ashwini S; Balakrishna, Sharath; Whittington, Dale; Shen, Jiang-Cheng; Emond, Mary J; Okabe, Takayoshi; Masutani, Chikahide; Hanaoka, Fumio; Nishimura, Susumu; Loeb, Lawrence A

    2014-08-01

    Translesion (TLS) DNA polymerases are specialized, error-prone enzymes that synthesize DNA across bulky, replication-stalling DNA adducts. In so doing, they facilitate the progression of DNA synthesis and promote cell proliferation. To potentiate the effect of cancer chemotherapeutic regimens, we sought to identify inhibitors of TLS DNA polymerases. We screened five libraries of ∼ 3000 small molecules, including one comprising ∼ 600 nucleoside analogs, for their effect on primer extension activity of DNA polymerase η (Pol η). We serendipitously identified sphingosine, a lipid-signaling molecule that robustly stimulates the activity of Pol η by ∼ 100-fold at low micromolar concentrations but inhibits it at higher concentrations. This effect is specific to the Y-family DNA polymerases, Pols η, κ, and ι. The addition of a single phosphate group on sphingosine completely abrogates this effect. Likewise, the inclusion of other sphingolipids, including ceramide and sphingomyelin to extension reactions does not elicit this response. Sphingosine increases the rate of correct and incorrect nucleotide incorporation while having no effect on polymerase processivity. Endogenous Pol η activity is modulated similarly as the recombinant enzyme. Importantly, sphingosine-treated cells exhibit increased lesion bypass activity, and sphingosine tethered to membrane lipids mimics the effects of free sphingosine. Our studies have uncovered sphingosine as a modulator of TLS DNA polymerase activity; this property of sphingosine may be associated with its known role as a signaling molecule in regulating cell proliferation in response to cellular stress. PMID:24928506

  17. An evaluation of the inhibition of human butyrylcholinesterase and acetylcholinesterase by the organophosphate chlorpyrifos oxon

    SciTech Connect

    Shenouda, Josephine; Green, Paula; Sultatos, Lester

    2009-12-01

    Acetylcholinesterase (EC 3.1.1.7) and butyrylcholinesterase (EC 3.1.1.8) are enzymes that belong to the superfamily of alpha/beta-hydrolase fold proteins. While they share many characteristics, they also possess many important differences. For example, whereas they have about 54% amino acid sequence identity, the active site gorge of acetylcholinesterase is considerably smaller than that of butyrylcholinesterase. Moreover, both have been shown to display simple and complex kinetic mechanisms, depending on the particular substrate examined, the substrate concentration, and incubation conditions. In the current study, incubation of butyrylthiocholine in a concentration range of 0.005-3.0 mM, with 317 pM human butyrylcholinesterase in vitro, resulted in rates of production of thiocholine that were accurately described by simple Michaelis-Menten kinetics, with a K{sub m} of 0.10 mM. Similarly, the inhibition of butyrylcholinesterase in vitro by the organophosphate chlorpyrifos oxon was described by simple Michaelis-Menten kinetics, with a k{sub i} of 3048 nM{sup -1} h{sup -1}, and a K{sub D} of 2.02 nM. In contrast to inhibition of butyrylcholinesterase, inhibition of human acetylcholinesterase by chlorpyrifos oxon in vitro followed concentration-dependent inhibition kinetics, with the k{sub i} increasing as the inhibitor concentration decreased. Chlorpyrifos oxon concentrations of 10 and 0.3 nM gave k{sub i}s of 1.2 and 19.3 nM{sup -1} h{sup -1}, respectively. Although the mechanism of concentration-dependent inhibition kinetics is not known, the much smaller, more restrictive active site gorge of acetylcholinesterase almost certainly plays a role. Similarly, the much larger active site gorge of butyrylcholinesterase likely contributes to its much greater reactivity towards chlorpyrifos oxon, compared to acetylcholinesterase.

  18. Local modulation of steroid action: rapid control of enzymatic activity

    PubMed Central

    Charlier, Thierry D.; Cornil, Charlotte A.; Patte-Mensah, Christine; Meyer, Laurence; Mensah-Nyagan, A. Guy; Balthazart, Jacques

    2015-01-01

    Estrogens can induce rapid, short-lived physiological and behavioral responses, in addition to their slow, but long-term, effects at the transcriptional level. To be functionally relevant, these effects should be associated with rapid modulations of estrogens concentrations. 17β-estradiol is synthesized by the enzyme aromatase, using testosterone as a substrate, but can also be degraded into catechol-estrogens via hydroxylation by the same enzyme, leading to an increase or decrease in estrogens concentration, respectively. The first evidence that aromatase activity (AA) can be rapidly modulated came from experiments performed in Japanese quail hypothalamus homogenates. This rapid modulation is triggered by calcium-dependent phosphorylations and was confirmed in other tissues and species. The mechanisms controlling the phosphorylation status, the targeted amino acid residues and the reversibility seem to vary depending of the tissues and is discussed in this review. We currently do not know whether the phosphorylation of the same amino acid affects both aromatase and/or hydroxylase activities or whether these residues are different. These processes provide a new general mechanism by which local estrogen concentration can be rapidly altered in the brain and other tissues. PMID:25852459

  19. Human serum albumin reduces the potency of acetylcholinesterase inhibitor based drugs for Alzheimer's disease.

    PubMed

    Islam, Mullah Muhaiminul; Gurung, Arun Bahadur; Bhattacharjee, Atanu; Aguan, Kripamoy; Mitra, Sivaprasad

    2016-04-01

    Human serum albumin (HSA) induced modulation of acetylcholinesterase (AChE) inhibition activity of four well-known cholinergic inhibitors like tacrine hydrochloride (TAC), donepezil hydrochloride monohydrate (DON), (-) Huperzine A (HuPA), eserine (ESE) was monitored quantitatively by Ellman's method. Kinetic analysis of enzyme hydrolysis reaction revealed that while the mechanism of inhibition does not change significantly, the inhibition efficiency changes drastically in presence of HSA, particularly for DON and TAC. However, interestingly, no notable difference was observed in the cases of HuPA and/or ESE. For example, the IC50 value of AChE inhibition increases by almost 135% in presence of ∼250 μM HSA (IC50 = 159 ± 8 nM) while comparing with aqueous buffer solution of pH 8.0 (IC50 = 68 ± 4 nM) in DON. On the other hand, the change is almost insignificant (<10%) in case of HuPA under the similar condition. The experimentally observed difference in the extent of modulatory effect was correlated with the sequestration ability of HSA towards different drugs predicted from molecular docking calculations. The result in this study demonstrates the importance to consider the plasma protein binding tendency of a newly synthesized AD drug before claiming its potency over the existing one. Further, development of new and intelligent delivery medium that shields the administered drugs from serum adsorption may reduce the optimal drug dose requirement. PMID:26902639

  20. Cholesterol modulates alkaline phosphatase activity of rat intestinal microvillus membranes.

    PubMed

    Brasitus, T A; Dahiya, R; Dudeja, P K; Bissonnette, B M

    1988-06-25

    Experiments were conducted, using a nonspecific lipid transfer protein, to vary the cholesterol/phospholipid molar ratio of rat proximal small intestinal microvillus membranes in order to assess the possible role of cholesterol in modulating enzymatic activities of this plasma membrane. Cholesterol/phospholipid molar ratios from 0.71 to 1.30 were produced from a normal value of 1.05 by incubation with the transfer protein and an excess of either phosphatidylcholine or cholesterol/phosphatidylcholine liposomes for 60 min at 37 degrees C. Cholesterol loading or depletion of the membranes was accompanied by a decrease or increase, respectively, in their lipid fluidity, as assessed by steady-state fluorescence polarization techniques using the lipid-soluble fluorophore 1,6-diphenyl-1,3,5-hexatriene. Increasing the cholesterol/phospholipid molar ratio also decreased alkaline phosphatase specific activity by approximately 20-30%, whereas decreasing this ratio increased this enzymatic activity by 20-30%. Sucrase, maltase, and lactase specific activities were not affected in these same preparations. Since the changes in alkaline phosphatase activity could be secondary to alterations in fluidity, cholesterol, or both, additional experiments were performed using benzyl alcohol, a known fluidizer. Benzyl alcohol (25 mM) restored the fluidity of cholesterol-enriched preparations to control levels, did not change the cholesterol/phospholipid molar ratio, and failed to alter alkaline phosphatase activity. These findings, therefore, indicate that alterations in the cholesterol content and cholesterol/phospholipid molar ratio of microvillus membranes can modulate alkaline phosphatase but not sucrase, maltase, or lactase activities. Moreover, membrane fluidity does not appear to be an important physiological regulator of these enzymatic activities. PMID:3379034

  1. Decorin binds myostatin and modulates its activity to muscle cells

    SciTech Connect

    Miura, Takayuki; Kishioka, Yasuhiro; Wakamatsu, Jun-ichi; Hattori, Akihito; Hennebry, Alex; Berry, Carole J.; Sharma, Mridula; Kambadur, Ravi; Nishimura, Takanori . E-mail: nishi@anim.agr.hokudai.ac.jp

    2006-02-10

    Myostatin, a member of TGF-{beta} superfamily of growth factors, acts as a negative regulator of skeletal muscle mass. The mechanism whereby myostatin controls the proliferation and differentiation of myogenic cells is mostly clarified. However, the regulation of myostatin activity to myogenic cells after its secretion in the extracellular matrix (ECM) is still unknown. Decorin, a small leucine-rich proteoglycan, binds TGF-{beta} and regulates its activity in the ECM. Thus, we hypothesized that decorin could also bind to myostatin and participate in modulation of its activity to myogenic cells. In order to test the hypothesis, we investigated the interaction between myostatin and decorin by surface plasmon assay. Decorin interacted with mature myostatin in the presence of concentrations of Zn{sup 2+} greater than 10 {mu}M, but not in the absence of Zn{sup 2+}. Kinetic analysis with a 1:1 binding model resulted in dissociation constants (K {sub D}) of 2.02 x 10{sup -8} M and 9.36 x 10{sup -9} M for decorin and the core protein of decorin, respectively. Removal of the glycosaminoglycan chain by chondroitinase ABC digestion did not affect binding, suggesting that decorin could bind to myostatin with its core protein. Furthermore, we demonstrated that immobilized decorin could rescue the inhibitory effect of myostatin on myoblast proliferation in vitro. These results suggest that decorin could trap myostatin and modulate its activity to myogenic cells in the ECM.

  2. Brg1 modulates enhancer activation in mesoderm lineage commitment

    SciTech Connect

    Alexander, Jeffrey M.; Hota, Swetansu K.; He, Daniel; Thomas, Sean; Ho, Lena; Pennacchio, Len A.; Bruneau, B. G.

    2015-03-26

    The interplay between different levels of gene regulation in modulating developmental transcriptional programs, such as histone modifications and chromatin remodeling, is not well understood. Here, we show that the chromatin remodeling factor Brg1 is required for enhancer activation in mesoderm induction. In an embryonic stem cell-based directed differentiation assay, the absence of Brg1 results in a failure of cardiomyocyte differentiation and broad deregulation of lineage-specific gene expression during mesoderm induction. We find that Brg1 co-localizes with H3K27ac at distal enhancers and is required for robust H3K27 acetylation at distal enhancers that are activated during mesoderm induction. Brg1 is also required to maintain Polycomb-mediated repression of non-mesodermal developmental regulators, suggesting cooperativity between Brg1 and Polycomb complexes. Thus, Brg1 is essential for modulating active and repressive chromatin states during mesoderm lineage commitment, in particular the activation of developmentally important enhancers. In conclusion, these findings demonstrate interplay between chromatin remodeling complexes and histone modifications that, together, ensure robust and broad gene regulation during crucial lineage commitment decisions.

  3. Brg1 modulates enhancer activation in mesoderm lineage commitment

    DOE PAGESBeta

    Alexander, Jeffrey M.; Hota, Swetansu K.; He, Daniel; Thomas, Sean; Ho, Lena; Pennacchio, Len A.; Bruneau, B. G.

    2015-03-26

    The interplay between different levels of gene regulation in modulating developmental transcriptional programs, such as histone modifications and chromatin remodeling, is not well understood. Here, we show that the chromatin remodeling factor Brg1 is required for enhancer activation in mesoderm induction. In an embryonic stem cell-based directed differentiation assay, the absence of Brg1 results in a failure of cardiomyocyte differentiation and broad deregulation of lineage-specific gene expression during mesoderm induction. We find that Brg1 co-localizes with H3K27ac at distal enhancers and is required for robust H3K27 acetylation at distal enhancers that are activated during mesoderm induction. Brg1 is also requiredmore » to maintain Polycomb-mediated repression of non-mesodermal developmental regulators, suggesting cooperativity between Brg1 and Polycomb complexes. Thus, Brg1 is essential for modulating active and repressive chromatin states during mesoderm lineage commitment, in particular the activation of developmentally important enhancers. In conclusion, these findings demonstrate interplay between chromatin remodeling complexes and histone modifications that, together, ensure robust and broad gene regulation during crucial lineage commitment decisions.« less

  4. Antioxidant, antimicrobial and neutrophil-modulating activities of herb extracts.

    PubMed

    Denev, Petko; Kratchanova, Maria; Ciz, Milan; Lojek, Antonin; Vasicek, Ondrej; Blazheva, Denitsa; Nedelcheva, Plamena; Vojtek, Libor; Hyrsl, Pavel

    2014-01-01

    The present study provides a comprehensive data on the antioxidant, antimicrobial and neutrophil-modulating activities of extracts from six medicinal plants--blackberry (Rubus fruticosus) leaves, chokeberry (Aronia melanocarpa) leaves, hawthorn (Crataegus monogyna) leaves, lady's mantle (Alchemilla glabra) aerial parts, meadowsweet (Filipendula ulmaria) aerial parts and raspberry (Rubus idaeus) leaves. In order to analyze the antioxidant activity of the herbs, several methods (ORAC, TRAP, HORAC and inhibition of lipid peroxidation) were used. Blackberry leaves and meadowsweet extracts revealed the highest antioxidant activities via all methods. All extracts studied blocked almost completely the opsonized zymosan particle-activated ROS production by neutrophils from human whole blood. On the other hand, the effect of extracts on phorbol myristate acetate-activated ROS production was much milder and even nonsignificant in the case of chokeberry leaves. This latter result suggests that extracts (apart from their antioxidative activity) interfere with the signaling cascade of phagocyte activation upstream of the protein kinase C activation. The antimicrobial activity of the investigated extracts against 11 human pathogens was investigated using three different methods. Meadowsweet and blackberry leaves extracts had the highest antimicrobial effect and the lowest minimal inhibiting concentrations (MICs) against the microorganisms tested. PMID:24945135

  5. Active dielectric antenna on chip for spatial light modulation

    PubMed Central

    Qiu, Ciyuan; Chen, Jianbo; Xia, Yang; Xu, Qianfan

    2012-01-01

    Integrated photonic resonators are widely used to manipulate light propagation in an evanescently-coupled waveguide. While the evanescent coupling scheme works well for planar optical systems that are naturally waveguide based, many optical applications are free-space based, such as imaging, display, holographics, metrology and remote sensing. Here we demonstrate an active dielectric antenna as the interface device that allows the large-scale integration capability of silicon photonics to serve the free-space applications. We show a novel perturbation-base diffractive coupling scheme that allows a high-Q planer resonator to directly interact with and manipulate free-space waves. Using a silicon-based photonic crystal cavity whose resonance can be rapidly tuned with a p-i-n junction, a compact spatial light modulator with an extinction ratio of 9.5 dB and a modulation speed of 150 MHz is demonstrated. Method to improve the modulation speed is discussed. PMID:23152946

  6. Regulating the regulators: modulators of transcription factor activity.

    PubMed

    Everett, Logan; Hansen, Matthew; Hannenhalli, Sridhar

    2010-01-01

    Gene transcription is largely regulated by DNA-binding transcription factors (TFs). However, the TF activity itself is modulated via, among other things, post-translational modifications (PTMs) by specific modification enzymes in response to cellular stimuli. TF-PTMs thus serve as "molecular switchboards" that map upstream signaling events to the downstream transcriptional events. An important long-term goal is to obtain a genome-wide map of "regulatory triplets" consisting of a TF, target gene, and a modulator gene that specifically modulates the regulation of the target gene by the TF. A variety of genome-wide data sets can be exploited by computational methods to obtain a rough map of regulatory triplets, which can guide directed experiments. However, a prerequisite to developing such computational tools is a systematic catalog of known instances of regulatory triplets. We first describe PTM-Switchboard, a recent database that stores triplets of genes such that the ability of one gene (the TF) to regulate a target gene is dependent on one or more PTMs catalyzed by a third gene, the modifying enzyme. We also review current computational approaches to infer regulatory triplets from genome-wide data sets and conclude with a discussion of potential future research. PTM-Switchboard is accessible at http://cagr.pcbi.upenn.edu/PTMswitchboard / PMID:20827600

  7. Modulation of inferotemporal cortex activation during verbal working memory maintenance

    PubMed Central

    Fiebach, Christian J.; Rissman, Jesse; D'Esposito, Mark

    2015-01-01

    Summary Regions of the left inferotemporal cortex are involved in visual word recognition and semantics. We utilized functional magnetic resonance imaging to localize an inferotemporal language area and to demonstrate that this area is involved in the active maintenance of visually presented words in working memory. Maintenance activity in this inferotemporal area showed an effect of memory load for words, but not pseudowords. The selective modulation of this language-related inferotemporal area for the maintenance of words, in the absence of visual input, is accompanied by an increased functional connectivity with left prefrontal cortex. These results are the first demonstration of an involvement of inferotemporal cortex in verbal working memory. They provide neurophysiological support for the notion that nonphonological language representations can be recruited in the service of verbal working memory. More generally, they suggest that verbal working memory should be conceptualized as the frontally-guided, sustained activation of pre-existing cortical language representations. PMID:16846859

  8. Modulating enzyme activity using ionic liquids or surfactants.

    PubMed

    Goldfeder, Mor; Fishman, Ayelet

    2014-01-01

    One of the important strategies for modulating enzyme activity is the use of additives to affect their microenvironment and subsequently make them suitable for use in different industrial processes. Ionic liquids (ILs) have been investigated extensively in recent years as such additives. They are a class of solvents with peculiar properties and a "green" reputation in comparison to classical organic solvents. ILs as co-solvents in aqueous systems have an effect on substrate solubility, enzyme structure and on enzyme-water interactions. These effects can lead to higher reaction yields, improved selectivity, and changes in substrate specificity, and thus there is great potential for IL incorporation in biocatalysis. The use of surfactants, which are usually denaturating agents, as additives in enzymatic reactions is less reviewed in recent years. However, interesting modulations in enzyme activity in their presence have been reported. In the case of surfactants there is a more pronounced effect on the enzyme structure, as can be observed in a number of crystal structures obtained in their presence. For each additive and enzymatic process, a specific optimization process is needed and there is no one-fits-all solution. Combining ILs and surfactants in either mixed micelles or water-in-IL microemulsions for use in enzymatic reaction systems is a promising direction which may further expand the range of enzyme applications in industrial processes. While many reviews exist on the use of ILs in biocatalysis, the present review centers on systems in which ILs or surfactants were able to modulate and improve the natural activity of enzymes in aqueous systems. PMID:24281758

  9. Active stiffness modulation of fins using macro fiber composites

    NASA Astrophysics Data System (ADS)

    Kancharala, Ashok K.; Philen, Michael K.

    2013-04-01

    Studies on the role of body flexibility in propulsion suggest that fish have the ability to control or modulate the stiffness of the fin for optimized propulsive performance. Fins with certain stiffness might be efficient for a particular set of operating parameters but may be inefficient for other parameters. Therefore active stiffness modulation of a fin can improve the propulsive performance for a range of operating conditions. This paper discusses the preliminary experimental work on the open loop active deformation control of heaving flexible fins using Macro Fiber Composites (MFCs). The effect of important parameters such as oscillation frequency, flexibility of the fin, applied voltage and the phase difference between applied voltage and heaving on propulsive performance are studied and reported. The results indicate that propulsive performance can be improved by active control of the fins. The mean thrust improved by 30- 38% for the fins used in the experiments. The phase difference of ~90° is found to be optimal for maximized propulsive performance for the parameters considered in the study. Furthermore, there exists an optimal voltage magnitude at which the propulsive performance is a maximum for the range of operating conditions.

  10. Modulation of nitric oxide synthase activity in macrophages

    PubMed Central

    Jorens, P. G.; Matthys, K. E.

    1995-01-01

    L-Arginine is converted to the highly reactive and unstable nitric oxide (NO) and L-citrulline by an enzyme named nitric oxide synthase (NOS). NO decomposes into other nitrogen oxides such as nitrite (NO2-) and nitrate (NO2-), and in the presence of superoxide anion to the potent oxidizing agent peroxynitrite (ONOO−). Activated rodent macrophages are capable of expressing an inducible form of this enzyme (iNOS) in response to appropriate stimuli, i.e., lipopolysaccharide (LPS) and interferon-γ (IFNγ). Other cytokines can modulate the induction of NO biosynthesis in macrophages. NO is a major effector molecule of the anti-microbial and cytotoxic activity of rodent macrophages against certain micro-organisms and tumour cells, respectively. The NO synthesizing pathway has been demonstrated in human monocytes and other cells, but its role in host defence seems to be accessory. A delicate functional balance between microbial stimuli, host-derived cytokines and hormones in the microenvironment regulates iNOS expression. This review will focus mainly on the known and proposed mechanisms of the regulation of iNOS induction, and on agents that can modulate NO release once the active enzyme has been expressed in the macrophage. PMID:18475620

  11. Target cell-specific modulation of neuronal activity by astrocytes

    NASA Astrophysics Data System (ADS)

    Kozlov, A. S.; Angulo, M. C.; Audinat, E.; Charpak, S.

    2006-06-01

    Interaction between astrocytes and neurons enriches the behavior of brain circuits. By releasing glutamate and ATP, astrocytes can directly excite neurons and modulate synaptic transmission. In the rat olfactory bulb, we demonstrate that the release of GABA by astrocytes causes long-lasting and synchronous inhibition of mitral and granule cells. In addition, astrocytes release glutamate, leading to a selective activation of granule-cell NMDA receptors. Thus, by releasing excitatory and inhibitory neurotransmitters, astrocytes exert a complex modulatory control on the olfactory network. glutamate | GABA | inhibition | olfactory bulb | synchronization

  12. [Design, synthesis and evaluation of N-acyl-4-phenylthiazole-2-amines as acetylcholinesterase inhibitors].

    PubMed

    Ma, Zheng-Yue; Yang, Qi; Zhang, Yuan-Gong; Li, Jun-Jie; Yang, Geng-Liang

    2014-06-01

    N-Acyl-4-phenylthiazole-2-amines were designed and synthesized, moreover their effects on acetylcholinesterase activities were tested. N-Acyl-4-phenylthiazole-2-amines were prepared from substituted 2-bromo-1-acetophenones by three steps reaction, and their AChE inhibitory activities were measured by Ellman method in vitro. The results showed that the target compounds had a certain inhibitory activity on AChE in vitro. Among them, 8c was the best, and IC50 of 8c was 0.51 micromol x L(-1), better than that of rivastigmine and Huperzine-A. The inhibitory activities of N-acyl-4-phenylthiazole-2-amines on acetylcholinesterase are worth while to be further studied. PMID:25212025

  13. Visual Experience Modulates Spatio-Temporal Dynamics of Circuit Activation

    PubMed Central

    Wang, Lang; Fontanini, Alfredo; Maffei, Arianna

    2011-01-01

    Persistent reduction in sensory drive in early development results in multiple plastic changes of different cortical synapses. How these experience-dependent modifications affect the spatio-temporal dynamics of signal propagation in neocortical circuits is poorly understood. Here we demonstrate that brief visual deprivation significantly affects the propagation of electrical signals in the primary visual cortex. The spatio-temporal spread of circuit activation upon direct stimulation of its input layer (Layer 4) is reduced, as is the activation of L2/3 – the main recipient of the output from L4. Our data suggest that the decrease in spatio-temporal activation of L2/3 depends on reduced L4 output, and is not intrinsically generated within L2/3. The data shown here suggest that changes in the synaptic components of the visual cortical circuit result not only in alteration of local integration of excitatory and inhibitory inputs, but also in a significant decrease in overall circuit activation. Furthermore, our data indicate a differential effect of visual deprivation on L4 and L2/3, suggesting that while feedforward activation of L2/3 is reduced, its activation by long range, within layer inputs is unaltered. Thus, brief visual deprivation induces experience-dependent circuit re-organization by modulating not only circuit excitability, but also the spatio-temporal patterns of cortical activation within and between layers. PMID:21743804

  14. Modulation of locomotor activation by the rostromedial tegmental nucleus.

    PubMed

    Lavezzi, Heather N; Parsley, Kenneth P; Zahm, Daniel S

    2015-02-01

    The rostromedial tegmental nucleus (RMTg) is a strong inhibitor of dopamine neurons in the ventral tegmental area (VTA) reported to influence neurobiological and behavioral responses to reward omission, aversive and fear-eliciting stimuli, and certain drugs of abuse. Insofar as previous studies implicate ventral mesencephalic dopamine neurons as an essential component of locomotor activation, we hypothesized that the RMTg also should modulate locomotion activation. We observed that bilateral infusions into the RMTg of the gamma-aminobutyric acid A (GABAA) agonist, muscimol, indeed activate locomotion. Alternatively, bilateral RMTg infusions of the GABAA receptor antagonist, bicuculline, suppress robust activations of locomotion elicited in two distinct ways: (1) by disinhibitory stimulation of neurons in the lateral preoptic area and (2) by return of rats to an environment previously paired with amphetamine administration. The possibility that suppressive locomotor effects of RMTg bicuculline infusions were due to unintended spread of drug to the nearby VTA was falsified by a control experiment showing that bilateral infusions of bicuculline into the VTA produce activation rather than suppression of locomotion. These results objectively implicate the RMTg in the regulation of locomotor activation. The effect is important because much evidence reported in the literature suggests that locomotor activation can be an involuntary behavioral expression of expectation and/or want without which the willingness to execute adaptive behaviors is impaired. PMID:25164249

  15. EarthScope Content Module for IRIS Active Earth Monitor

    NASA Astrophysics Data System (ADS)

    McQuillan, P. J.; Welti, R.; Johnson, J. A.; Shiffman, C. R.; Olds, S. E.

    2012-12-01

    The Active Earth Monitor (AEM) is an interactive computer-based display for university lobbies, museums, visitor centers, schools and libraries. AEM runs in a standard Internet web browser in full screen mode. The display consists of a customizable set of content pages about plate tectonics, earthquakes, volcanoes and tsunamis. Low-cost and simple-to-implement, the Active Earth Monitor provides a way to engage audiences with earth science information without spending resources on a large exhibit. The EarthScope Active Earth Monitor content set highlights the connections between the landscape and the research and monitoring being conducted by EarthScope in partnership with regional monitoring networks. Modules consist of chapters that focus on What is EarthScope?, EarthScope Observatories, and EarthScope Research Results. Content topics are easily explored using a web page button type navigation interface via a touch screen or mouse. A formative evaluation of general public users informed the interface design. Chapters in the modules start with a general overview and proceed to detailed specifics. Each chapter utilizes at least one set of live or near real-time research data (often more than one). This exposes the general public to active ongoing research that is engaging, relevant to the individual user, and explained in easy to understand terms. All live content is updated each time a user accesses the individual page displaying the live data. Leading questions are presented allowing the user to examine the content before accessing the answer via pop-up box. Diagrams and charts of research data have explanatory keys that allow users to self explore all content. Content pages can be created and inserted in the Active Earth Monitor by utilizing the simple HTML/CSS coding.;

  16. Simulations of the equatorial thermosphere anomaly: Geomagnetic activity modulation

    NASA Astrophysics Data System (ADS)

    Lei, Jiuhou; Wang, Wenbin; Thayer, Jeffrey P.; Luan, Xiaoli; Dou, Xiankang; Burns, Alan G.; Solomon, Stanley C.

    2014-08-01

    The modulation of geomagnetic activity on the equatorial thermosphere anomaly (ETA) in thermospheric temperature under the high solar activity condition is investigated using the Thermosphere Ionosphere Electrodynamics General Circulation Model simulations. The model simulations during the geomagnetically disturbed interval, when the north-south component of the interplanetary magnetic field (Bz) oscillates between southward and northward directions, are analyzed and also compared with those under the quiet time condition. Our results show that ionospheric electron densities increase greatly in the equatorial ionization anomaly (EIA) crest region and decrease around the magnetic equator during the storm time, resulting from the enhanced eastward electric fields. The impact of both the direct heat deposition at high latitudes and the modulation of the storm time enhanced EIA crests on the ETA are subsequently studied. The increased plasma densities over the EIA crest region enhance the field-aligned ion drag that accelerates the poleward meridional winds and consequently their associated adiabatic cooling effect. This process alone produces a deeper temperature trough over the magnetic equator as a result of the enhanced divergence of meridional winds. Moreover, the enhanced plasma-neutral collisional heating at higher latitudes associated with the ionospheric positive storm effect causes a weak increase of the ETA crests. On the other hand, strong changes of the neutral temperature are mainly confined to higher latitudes. Nevertheless, the changes of the ETA purely due to the increased plasma density are overwhelmed by those associated with the storm time heat deposition, which is the major cause of an overall elevated temperature in both the ETA crests and trough during the geomagnetically active period. Associated with the enhanced neutral temperature at high latitudes due to the heat deposition, the ETA crest-trough differences become larger under the minor

  17. In vitro inhibition of acetylcholinesterase by crude plant extracts from Colombian flora.

    PubMed

    Niño, Jaime; Hernández, Jimmy A; Correa, Yaned M; Mosquera, Oscar M

    2006-11-01

    The methanol extracts from five different plant families (Asteraceae, Euphorbiaceae, Melastomataceae, Rubiaceae, and Solanaceae) collected at Regional Natural Park Ucumarí (Colombia), were screened for their acetylcholinesterase inhibitory activity through the modified Ellman's spectrophotometric method. The best inhibitory activities on this study were shown by the extracts of Solanum leucocarpum Dunal (IC50 = 204.59 mg/l) and Witheringia coccoloboides (Damm) (IC50 = 220.68 mg/l), both plants belonging to the Solanaceae family. PMID:17160288

  18. Modulation of human motoneuron activity by a mental arithmetic task.

    PubMed

    Bensoussan, Laurent; Duclos, Yann; Rossi-Durand, Christiane

    2012-10-01

    This study aimed to determine whether the performance of a mental task affects motoneuron activity. To this end, the tonic discharge pattern of wrist extensor motor units was analyzed in healthy subjects while they were required to maintain a steady wrist extension force and to concurrently perform a mental arithmetic (MA) task. A shortening of the mean inter-spike interval (ISI) and a decrease in ISI variability occurred when MA task was superimposed to the motor task. Aloud and silent MA affected equally the rate and variability of motoneuron discharge. Increases in surface EMG activity and force level were consistent with the modulation of the motor unit discharge rate. Trial-by-trial analysis of the characteristics of motor unit firing revealed that performing MA increases activation of wrist extensor SMU. It is suggested that increase in muscle spindle afferent activity, resulting from fusimotor drive activation by MA, may have contributed to the increase in synaptic inputs to motoneurons during the mental task performance, likely together with enhancement in the descending drive. The finding that a mental task affects motoneuron activity could have consequences in assessment of motor disabilities and in rehabilitation in motor pathologies. PMID:23159444

  19. Light/dark modulation of enzyme activity in photosynthesis

    SciTech Connect

    Anderson, L.E.; Ashton, A.R.; Mohamed, A.H.; Scheibe, R.

    1982-02-01

    In photosynthetic species ranging from cyanobacteria to higher plants, many enzymes are light modulated. Most of the known light modulated enzymes are chloroplastic. Four mechanisms of modulation have been proposed. One function of light modulation is probably the autocatalytic build-up of reductive pentose phosphate cycle intermediates during the induction period of photosynthetic CO/sub 2/ fixation.

  20. Integrated Brain Circuits: Astrocytic Networks Modulate Neuronal Activity and Behavior

    PubMed Central

    Halassa, Michael M.; Haydon, Philip G.

    2011-01-01

    The past decade has seen an explosion of research on roles of neuron-astrocyte interactions in the control of brain function. We highlight recent studies performed on the tripartite synapse, the structure consisting of pre- and postsynaptic elements of the synapse and an associated astrocytic process. Astrocytes respond to neuronal activity and neuro-transmitters, through the activation of metabotropic receptors, and can release the gliotransmitters ATP, D-serine, and glutamate, which act on neurons. Astrocyte-derived ATP modulates synaptic transmission, either directly or through its metabolic product adenosine. D-serine modulates NMDA receptor function, whereas glia-derived glutamate can play important roles in relapse following withdrawal from drugs of abuse. Cell type–specific molecular genetics has allowed a new level of examination of the function of astrocytes in brain function and has revealed an important role of these glial cells that is mediated by adenosine accumulation in the control of sleep and in cognitive impairments that follow sleep deprivation. PMID:20148679

  1. Dopamine Modulates the Activity of Sensory Hair Cells

    PubMed Central

    Toro, Cecilia; Trapani, Josef G.; Pacentine, Itallia; Maeda, Reo; Sheets, Lavinia; Mo, Weike

    2015-01-01

    The senses of hearing and balance are subject to modulation by efferent signaling, including the release of dopamine (DA). How DA influences the activity of the auditory and vestibular systems and its site of action are not well understood. Here we show that dopaminergic efferent fibers innervate the acousticolateralis epithelium of the zebrafish during development but do not directly form synapses with hair cells. However, a member of the D1-like receptor family, D1b, tightly localizes to ribbon synapses in inner ear and lateral-line hair cells. To assess modulation of hair-cell activity, we reversibly activated or inhibited D1-like receptors (D1Rs) in lateral-line hair cells. In extracellular recordings from hair cells, we observed that D1R agonist SKF-38393 increased microphonic potentials, whereas D1R antagonist SCH-23390 decreased microphonic potentials. Using ratiometric calcium imaging, we found that increased D1R activity resulted in larger calcium transients in hair cells. The increase of intracellular calcium requires Cav1.3a channels, as a Cav1 calcium channel antagonist, isradipine, blocked the increase in calcium transients elicited by the agonist SKF-38393. Collectively, our results suggest that DA is released in a paracrine fashion and acts at ribbon synapses, likely enhancing the activity of presynaptic Cav1.3a channels and thereby increasing neurotransmission. SIGNIFICANCE STATEMENT The neurotransmitter dopamine acts in a paracrine fashion (diffusion over a short distance) in several tissues and bodily organs, influencing and regulating their activity. The cellular target and mechanism of the action of dopamine in mechanosensory organs, such as the inner ear and lateral-line organ, is not clearly understood. Here we demonstrate that dopamine receptors are present in sensory hair cells at synaptic sites that are required for signaling to the brain. When nearby neurons release dopamine, activation of the dopamine receptors increases the activity of

  2. Space station group activities habitability module study: A synopsis

    NASA Technical Reports Server (NTRS)

    Nixon, David; Glassman, Terry

    1987-01-01

    Space station habitability was studied by investigating crew activity routines, proximities, ergonomic envelopes, and group volumes. Ten alternative schematic interior designs were proposed. Preliminary conclusions include: (1) in-service interior modifications may be necessary and should be planned for; (2) design complexity will be increased if the module cluster is reduced from five to three; (3) the increased crew circulation attendant upon enhancement of space station activity may produce human traffic bottlenecks and should be planned for; (4) a single- or two-person quiet area may be desirable to provide crew members with needed solitude during waking hours; and (5) the decision to choose a two-shift or three-shift daily cycle will have a significant impact on the design configuration and operational efficiency of the human habitat.

  3. Ligand Mobility Modulates Immunological Synapse Formation and T Cell Activation

    PubMed Central

    Hsu, Chih-Jung; Hsieh, Wan-Ting; Waldman, Abraham; Clarke, Fiona; Huseby, Eric S.; Burkhardt, Janis K.; Baumgart, Tobias

    2012-01-01

    T cell receptor (TCR) engagement induces clustering and recruitment to the plasma membrane of many signaling molecules, including the protein tyrosine kinase zeta-chain associated protein of 70 kDa (ZAP70) and the adaptor SH2 domain-containing leukocyte protein of 76 kDa (SLP76). This molecular rearrangement results in formation of the immunological synapse (IS), a dynamic protein array that modulates T cell activation. The current study investigates the effects of apparent long-range ligand mobility on T cell signaling activity and IS formation. We formed stimulatory lipid bilayers on glass surfaces from binary lipid mixtures with varied composition, and characterized these surfaces with respect to diffusion coefficient and fluid connectivity. Stimulatory ligands coupled to these surfaces with similar density and orientation showed differences in their ability to activate T cells. On less mobile membranes, central supramolecular activation cluster (cSMAC) formation was delayed and the overall accumulation of CD3ζ at the IS was reduced. Analysis of signaling microcluster (MC) dynamics showed that ZAP70 MCs exhibited faster track velocity and longer trajectories as a function of increased ligand mobility, whereas movement of SLP76 MCs was relatively insensitive to this parameter. Actin retrograde flow was observed on all surfaces, but cell spreading and subsequent cytoskeletal contraction were more pronounced on mobile membranes. Finally, increased tyrosine phosphorylation and persistent elevation of intracellular Ca2+ were observed in cells stimulated on fluid membranes. These results point to ligand mobility as an important parameter in modulating T cell responses. PMID:22384241

  4. Modulation of CD44 Activity by A6-Peptide

    PubMed Central

    Finlayson, Malcolm

    2015-01-01

    Hyaluronan (HA) is a non-sulfated glycosaminoglycan distributed throughout the extracellular matrix that plays a major role in cell adhesion, migration, and proliferation. CD44, a multifunctional cell surface glycoprotein, is a receptor for HA. In addition, CD44 is known to interact with other receptors and ligands, and to mediate a number of cellular functions as well as disease progression. Studies have shown that binding of HA to CD44 in cancer cells activates survival pathways resulting in cancer cell survival. This effect can be blocked by anti-CD44 monoclonal antibodies. A6 is a capped, eight l-amino acid peptide (Ac-KPSSPPEE-NH2) derived from the biologically active connecting peptide domain of the serine protease, human urokinase plasminogen activator (uPA). A6 neither binds to the uPA receptor (uPAR) nor interferes with uPA/uPAR binding. A6 binds to CD44 resulting in the inhibition of migration, invasion, and metastasis of tumor cells, and the modulation of CD44-mediated cell signaling. A6 has been shown to have no dose-limiting toxicity in animal studies. A6 has demonstrated efficacy and an excellent safety profile in Phase 1a, 1b, and 2 clinical trials. In animal models, A6 has also exhibited promising results for the treatment of diabetic retinopathy and wet age-related macular degeneration through the reduction of retinal vascular permeability and inhibition of choroidal neovascularization, respectively. Recently, A6 has been shown to be directly cytotoxic for B-lymphocytes obtained from patients with chronic lymphocytic leukemia expressing the kinase, ZAP-70. This review will discuss the activity of A6, A6 modulation of HA and CD44, and a novel strategy for therapeutic intervention in disease. PMID:25870596

  5. Dietary fat modulates serum paraoxonase 1 activity in rats.

    PubMed

    Kudchodkar, B J; Lacko, A G; Dory, L; Fungwe, T V

    2000-10-01

    We examined the effects of dietary fats with specific fatty acid compositions, on serum paraoxonase (PON1) activity in rats. Male adult Sprague-Dawley rats were divided randomly into four dietary groups. One group received the control diet [AIN 93M with soybean oil (5 g/100 g diet)], whereas the remaining three groups received the modified control diet supplemented with (15 g/100 g diet) triolein, tripalmitin or fish oil, respectively. After 20 d, blood was obtained after overnight food deprivation and PON1 activity was determined. Serum lipids and lipid components of lipoproteins were also determined. Serum PON1 activity [micromol/(L.min)] was significantly (P: < 0.05) higher in triolein (98 +/- 6) and lower in fish oil (41 +/- 4), compared with tripalmitin-fed rats (63 +/- 11). Serum PON1 activity in tripalmitin-fed rats was comparable to that of controls (67 +/- 9). Serum PON1 activity correlated significantly with serum lecithin:cholesterol acyltransferase (LCAT) activity (r = 0.77, P: < 0.001) and was transported in blood principally in association with the denser subfraction of HDL, very high density lipoprotein (VHDL; d > 1.15 kg/L). Serum PON1 activity correlated strongly with serum lipids as well as lipids of VLDL, HDL and its subfractions. Multiple linear regression analysis, however, showed a significant relationship of serum PON1 activity, principally with the phospholipids of VHDL (r = 0.47, P: < 0.002). These data suggest that the modulation of serum PON1 activity by dietary fat may be mediated via the effect of the specific fatty acids on the synthesis and secretion of VHDL, the subfraction of HDL that transports the majority of PON1 in the blood. PMID:11015468

  6. Effect of Donepezil, Tacrine, Galantamine and Rivastigmine on Acetylcholinesterase Inhibition in Dugesia tigrina.

    PubMed

    Bezerra da Silva, Cristiane; Pott, Arnildo; Elifio-Esposito, Selene; Dalarmi, Luciane; Fialho do Nascimento, Kátia; Moura Burci, Ligia; de Oliveira, Maislian; de Fátima Gaspari Dias, Josiane; Warumby Zanin, Sandra Maria; Gomes Miguel, Obdulio; Dallarmi Miguel, Marilis

    2016-01-01

    Dugesia tigrina is a non-parasitic platyhelminth, which has been recently utilized in pharmacological models, regarding the nervous system, as it presents a wide sensitivity to drugs. Our trials aimed to propose a model for an in vivo screening of substances with inhibitory activity of the enzyme acetylcholinesterase. Trials were performed with four drugs commercialized in Brazil: donepezil, tacrine, galantamine and rivastigmine, utilized in the control of Alzheimer's disease, to inhibit the activity of acetylcholinesterase. We tested five concentrations of the drugs, with an exposure of 24 h, and the mortality and the inhibition of acetylcholinesterase planarian seizure-like activity (pSLA) and planarian locomotor velocity (pLMV) were measured. Galantamine showed high anticholinesterasic activity when compared to the other drugs, with a reduction of 0.05 μmol·min(-1) and 63% of convulsant activity, presenting screw-like movement and hypokinesia, with pLMV of 65 crossed lines during 5 min. Our results showed for the first time the anticholinesterasic and convulsant effect, in addition to the decrease in locomotion induced by those drugs in a model of invertebrates. The experimental model proposed is simple and low cost and could be utilized in the screening of substances with anticholinesterasic action. PMID:26760993

  7. Modulation of cortical oscillatory activity during transcranial magnetic stimulation.

    PubMed

    Brignani, Debora; Manganotti, Paolo; Rossini, Paolo M; Miniussi, Carlo

    2008-05-01

    Transcranial magnetic stimulation (TMS) can transiently modulate cortical excitability, with a net effect depending on the stimulation frequency (< or =1 Hz inhibition vs. > or =5 Hz facilitation, at least for the motor cortex). This possibility has generated interest in experiments aiming to improve deficits in clinical settings, as well as deficits in the cognitive domain. The aim of the present study was to investigate the on-line effects of low frequency (1 Hz) TMS on the EEG oscillatory activity in the healthy human brain, focusing particularly on the outcome of these modulatory effects in relation to the duration of the TMS stimulation. To this end, we used the event-related desynchronization/synchronization (ERD/ERS) approach to determine the patterns of oscillatory activity during two consecutive trains of sham and real TMS. Each train of stimulation was delivered to the left primary motor cortex (MI) of healthy subjects over a period of 10 min, while EEG rhythms were simultaneously recorded. Results indicated that TMS induced an increase in the power of brain rhythms that was related to the period of the stimulation, i.e. the synchronization of the alpha band increased with the duration of the stimulation, and this increase was inversely correlated with motor-evoked potentials (MEPs) amplitude. In conclusion, low frequency TMS over primary motor cortex induces a synchronization of the background oscillatory activity on the stimulated region. This induced modulation in brain oscillations seems to increase coherently with the duration of stimulation, suggesting that TMS effects may involve short-term modification of the neural circuitry sustaining MEPs characteristics. PMID:17557296

  8. Preclinical and first-in-human evaluation of PRX-105, a PEGylated, plant-derived, recombinant human acetylcholinesterase-R

    SciTech Connect

    Atsmon, Jacob; Brill-Almon, Einat; Nadri-Shay, Carmit; Chertkoff, Raul; Alon, Sari; Shaikevich, Dimitri; Volokhov, Inna; Haim, Kirsten Y.; Bartfeld, Daniel; Shulman, Avidor; Ruderfer, Ilya; Ben-Moshe, Tehila; Shilovitzky, Orit; Soreq, Hermona; Shaaltiel, Yoseph

    2015-09-15

    PRX-105 is a plant-derived recombinant version of the human ‘read-through’ acetylcholinesterase splice variant (AChE-R). Its active site structure is similar to that of the synaptic variant, and it displays the same affinity towards organophosphorus (OP) compounds. As such, PRX-105 may serve as a bio-scavenger for OP pesticides and chemical warfare agents. To assess its potential use in prophylaxis and treatment of OP poisoning we conducted several preliminary tests, reported in this paper. Intravenous (IV) PRX-105 was administered to mice either before or after exposure to an OP toxin. All mice who received an IV dose of 50 nmol/kg PRX-105, 2 min before being exposed to 1.33 × LD{sub 50} and 1.5 × LD{sub 50} of toxin and 10 min after exposure to 1.5 × LD{sub 50} survived. The pharmacokinetic and toxicity profiles of PRX-105 were evaluated in mice and mini-pigs. Following single and multiple IV doses (50 to 200 mg/kg) no deaths occurred and no significant laboratory and histopathological changes were observed. The overall elimination half-life (t{sub ½}) in mice was 994 (± 173) min. Additionally, a first-in-human study, to assess the safety, tolerability and pharmacokinetics of the compound, was conducted in healthy volunteers. The t{sub ½} in humans was substantially longer than in mice (average 26.7 h). Despite the small number of animals and human subjects who were assessed, the fact that PRX-105 exerts a protective and therapeutic effect following exposure to lethal doses of OP, its favorable safety profile and its relatively long half-life, renders it a promising candidate for treatment and prophylaxis against OP poisoning and warrants further investigation. - Highlights: • PRX-105 is a PEGylated plant-derived recombinant human acetylcholinesterase-R. • PRX-105 is a promising bio-scavenger for organophosphorous toxins at lethal doses. • PRX-105 was shown to protect animals both prophylactically and post-poisoning. • First-in-human study

  9. Cinobufagin Modulates Human Innate Immune Responses and Triggers Antibacterial Activity

    PubMed Central

    Xie, Shanshan; Spelmink, Laura; Codemo, Mario; Subramanian, Karthik; Pütsep, Katrin

    2016-01-01

    The traditional Chinese medicine Chan-Su is widely used for treatment of cancer and cardiovascular diseases, but also as a remedy for infections such as furunculosis, tonsillitis and acute pharyngitis. The clinical use of Chan-Su suggests that it has anti-infective effects, however, the mechanism of action is incompletely understood. In particular, the effect on the human immune system is poorly defined. Here, we describe previously unrecognized immunomodulatory activities of cinobufagin (CBG), a major bioactive component of Chan-Su. Using human monocyte-derived dendritic cells (DCs), we show that LPS-induced maturation and production of a number of cytokines was potently inhibited by CBG, which also had a pro-apoptotic effect, associated with activation of caspase-3. Interestingly, CBG triggered caspase-1 activation and significantly enhanced IL-1β production in LPS-stimulated cells. Finally, we demonstrate that CBG upregulates gene expression of the antimicrobial peptides (AMPs) hBD-2 and hBD-3 in DCs, and induces secretion of HNP1-3 and hCAP-18/LL-37 from neutrophils, potentiating neutrophil antibacterial activity. Taken together, our data indicate that CBG modulates the inflammatory phenotype of DCs in response to LPS, and triggers an antibacterial innate immune response, thus proposing possible mechanisms for the clinical effects of Chan-Su in anti-infective therapy. PMID:27529866

  10. Superoxide radical and iron modulate aconitase activity in mammalian cells.

    PubMed

    Gardner, P R; Raineri, I; Epstein, L B; White, C W

    1995-06-01

    Aconitase is a member of a family of iron-sulfur-containing (de)hydratases whose activities are modulated in bacteria by superoxide radical (O2-.)-mediated inactivation and iron-dependent reactivation. The inactivation-reactivation of aconitase(s) in cultured mammalian cells was explored since these reactions may impact important and diverse aconitase functions in the cytoplasm and mitochondria. Conditions which increase O2-. production including exposure to the redox-cycling agent phenazine methosulfate (PMS), inhibitors of mitochondrial ubiquinol-cytochrome c oxidoreductase, or hyperoxia inactivated aconitase in mammalian cells. Overproduction of mitochondrial Mn-superoxide dismutase protected aconitase from inactivation by PMS or inhibitors of ubiquinol-cytochrome c oxidoreductase, but not from normobaric hyperoxia. Aconitase activity was reactivated (t1/2 of 12 +/- 3 min) upon removal of PMS. The iron chelator deferoxamine impaired reactivation and increased net inactivation of aconitase by O2-.. The ability of ubiquinol-cytochrome c oxidoreductase-generated O2-. to inactivate aconitase in several cell types correlated with the fraction of the aconitase activity localized in mitochondria. Extracellular O2-. generated with xanthine oxidase did not affect aconitase activity nor did exogenous superoxide dismutase decrease aconitase inactivation by PMS. The results demonstrate a dynamic and cyclical O2-.-mediated inactivation and iron-dependent reactivation of the mammalian [4Fe-4S] aconitases under normal and stress conditions and provide further evidence for the membrane compartmentalization of O2-.. PMID:7768942

  11. Cinobufagin Modulates Human Innate Immune Responses and Triggers Antibacterial Activity.

    PubMed

    Xie, Shanshan; Spelmink, Laura; Codemo, Mario; Subramanian, Karthik; Pütsep, Katrin; Henriques-Normark, Birgitta; Olliver, Marie

    2016-01-01

    The traditional Chinese medicine Chan-Su is widely used for treatment of cancer and cardiovascular diseases, but also as a remedy for infections such as furunculosis, tonsillitis and acute pharyngitis. The clinical use of Chan-Su suggests that it has anti-infective effects, however, the mechanism of action is incompletely understood. In particular, the effect on the human immune system is poorly defined. Here, we describe previously unrecognized immunomodulatory activities of cinobufagin (CBG), a major bioactive component of Chan-Su. Using human monocyte-derived dendritic cells (DCs), we show that LPS-induced maturation and production of a number of cytokines was potently inhibited by CBG, which also had a pro-apoptotic effect, associated with activation of caspase-3. Interestingly, CBG triggered caspase-1 activation and significantly enhanced IL-1β production in LPS-stimulated cells. Finally, we demonstrate that CBG upregulates gene expression of the antimicrobial peptides (AMPs) hBD-2 and hBD-3 in DCs, and induces secretion of HNP1-3 and hCAP-18/LL-37 from neutrophils, potentiating neutrophil antibacterial activity. Taken together, our data indicate that CBG modulates the inflammatory phenotype of DCs in response to LPS, and triggers an antibacterial innate immune response, thus proposing possible mechanisms for the clinical effects of Chan-Su in anti-infective therapy. PMID:27529866

  12. Bacteria activate sensory neurons that modulate pain and inflammation

    PubMed Central

    Chiu, Isaac M.; Heesters, Balthasar A.; Ghasemlou, Nader; Von Hehn, Christian A.; Zhao, Fan; Tran, Johnathan; Wainger, Brian; Strominger, Amanda; Muralidharan, Sriya; Horswill, Alexander R.; Wardenburg, Juliane Bubeck; Hwang, Sun Wook; Carroll, Michael C.; Woolf, Clifford J.

    2013-01-01

    Summary Nociceptor sensory neurons are specialized to detect potentially damaging stimuli, protecting the organism by initiating the sensation of pain and eliciting defensive behaviors. Bacterial infections produce pain by unknown molecular mechanisms, although they are presumed secondary to immune activation. Here we demonstrate that bacteria directly activate nociceptors, and that the immune response mediated through TLR2, MyD88, T cells, B cells, and neutrophils/monocytes is not necessary for Staphylococcus aureus induced pain in mice. Mechanical and thermal hyperalgesia parallels live bacterial load rather than tissue swelling or immune activation. Bacteria induce calcium flux and action potentials in nociceptor neurons, in part via bacterial N-formylated peptides and the pore-forming toxin alpha-hemolysin through distinct mechanisms. Specific ablation of Nav1.8-lineage neurons, which include nociceptors, abrogated pain during bacterial infection, but concurrently increased local immune infiltration and lymphadenopathy of the draining lymph node. Thus, bacterial pathogens produce pain by directly activating sensory neurons that modulate inflammation, an unsuspected role for the nervous system in host-pathogen interactions. PMID:23965627

  13. In vitro inhibition of acetylcholinesterase from four marine species by organophosphates and carbamates

    SciTech Connect

    Galgani, F.; Bocquene, G. )

    1990-08-01

    The literature on the biological, physical, and pharmaceutical chemistry of cholinesterase is considerable and includes data on activators and inhibitors. Most of the work on specific anticholinesterasic agents has been concerned with carbamates and organophosphates. Because of the sensitivity of acetylcholinesterase to carbamates and organophosphates, the enzyme has been used as a biochemical indicator of pollution by these agents. However, the chemical reactivity of such chemicals has not been correlated with their effect on Ache and it is impossible to accurately predict biological effects based only on structure. The objectives of this study were to investigate the sensitivity of various marine animals to both organo-phosphates and carbamates. The study was conducted by assessing the in vitro effect of five organophosphates and three carbamates on acetylcholinesterase activity from the muscle of the shrimp Palaemon serratus, the fishes Scomber and Pleuronectes platessa, and from the whole mussels Mytilus edulis. All these species could be used for the monitoring of effect of pollutants.

  14. Acetylcholinesterase Inhibitors Reduce Neuroinflammation and -Degeneration in the Cortex and Hippocampus of a Surgery Stress Rat Model

    PubMed Central

    Sifringer, Marco; Tegethoff, Annalena; Paeschke, Nadine; Kostova, Mariya; Feldheiser, Aarne; Spies, Claudia D.

    2013-01-01

    Exogenous stress like tissue damage and pathogen invasion during surgical trauma could lead to a peripheral inflammatory response and induce neuroinflammation, which can result in postoperative cognitive dysfunction (POCD). The cholinergic anti-inflammatory pathway is a neurohumoral mechanism that plays a prominent role by suppressing the inflammatory response. Treatments with acetylcholinesterase inhibitors enhance cholinergic transmission and may therefore act as a potential approach to prevent neuroinflammation. In the presence or absence of acetylcholinesterase inhibitors, adult Wistar rats underwent surgery alone or were additionally treated with lipopolysaccharide (LPS). Physostigmine, which can overcome the blood-brain barrier or neostigmine acting only peripheral, served as acetylcholinesterase inhibitors. The expression of pro- and anti-inflammatory cytokines in the cortex, hippocampus, spleen and plasma was measured after 1 h, 24 h, 3 d and 7 d using Real-Time PCR, western blot analysis or cytometric bead array (CBA). Fluoro-Jade B staining of brain slices was employed to elucidate neurodegeneration. The activity of acetylcholinesterase was estimated using a spectrofluorometric method. Surgery accompanied by LPS-treatment led to increased IL-1beta gene and protein upregulation in the cortex and hippocampus but was significantly reduced by physostigmine and neostigmine. Furthermore, surgery in combination with LPS-treatment caused increased protein expression of IL-1, TNF-alpha and IL-10 in the spleen and plasma. Physostigmine and neostigmine significantly decreased the protein expression of IL-1 and TNF-alpha. Neuronal degeneration and the activity of acetylcholinesterase were elevated after surgery with LPS-treatment and reduced by physostigmine and neostigmine. Along with LPS-treatment, acetylcholinesterase inhibitors reduce the pro-inflammatory response as well as neurodegeneration after surgery in the cortex and hippocampus. This combination may

  15. Inactivation of acetylcholinesterase by various fluorophores.

    PubMed

    Guo, Lilu; Suarez, Alirica I; Thompson, Charles M

    2010-02-01

    The inhibition of recombinant mouse acetylcholinesterase (rMAChE) and electric eel acetylcholinesterase (EEAChE) by seven, structurally different chromophore-based (dansyl, pyrene, dabsyl, diethylamino- and methoxycoumarin, Lissamine rhodamine B, and Texas Red) propargyl carboxamides or sulfonamides was studied. Diethylaminocoumarin, Lissamine, and Texas Red amides inhibited rMAChE with IC50 values of 1.00 microM, 0.05 microM, and 0.70 microM, respectively. Lissamine and Texas Red amides inhibited EEAChE with IC50 values of 3.57 and 10.4 microM, respectively. The other chromophore amides did not inhibit either AChE. The surprising inhibitory potency of Lissamine was examined in further detail against EEAChE and revealed a mixed-type inhibition with Ki = 11.7 microM (competitive) and Ki' = 24.9 microM (noncompetitive), suggesting that Lissamine binds to free enzyme and enzyme-substrate complex. PMID:19842944

  16. Coco is a dual activity modulator of TGFβ signaling

    PubMed Central

    Deglincerti, Alessia; Haremaki, Tomomi; Warmflash, Aryeh; Sorre, Benoit; Brivanlou, Ali H.

    2015-01-01

    The TGFβ signaling pathway is a crucial regulator of developmental processes and disease. The activity of TGFβ ligands is modulated by various families of soluble inhibitors that interfere with the interactions between ligands and receptors. In an unbiased, genome-wide RNAi screen to identify genes involved in ligand-dependent signaling, we unexpectedly identified the BMP/Activin/Nodal inhibitor Coco as an enhancer of TGFβ1 signaling. Coco synergizes with TGFβ1 in both cell culture and Xenopus explants. Molecularly, Coco binds to TGFβ1 and enhances TGFβ1 binding to its receptor Alk5. Thus, Coco acts as both an inhibitor and an enhancer of signaling depending on the ligand it binds. This finding raises the need for a global reconsideration of the molecular mechanisms regulating TGFβ signaling. PMID:26116664

  17. Workshop Physics Activity Guide, Module 4: Electricity and Magnetism

    NASA Astrophysics Data System (ADS)

    Laws, Priscilla W.

    2004-05-01

    The Workshop Physics Activity Guide is a set of student workbooks designed to serve as the foundation for a two-semester calculus-based introductory physics course. It consists of 28 units that interweave text materials with activities that include prediction, qualitative observation, explanation, equation derivation, mathematical modeling, quantitative experiments, and problem solving. Students use a powerful set of computer tools to record, display, and analyze data, as well as to develop mathematical models of physical phenomena. The design of many of the activities is based on the outcomes of physics education research. The Workshop Physics Activity Guide is supported by an Instructor's Website that: (1) describes the history and philosophy of the Workshop Physics Project; (2) provides advice on how to integrate the Guide into a variety of educational settings; (3) provides information on computer tools (hardware and software) and apparatus; and (4) includes suggested homework assignments for each unit. Log on to the Workshop Physics Project website at http://physics.dickinson.edu/ Workshop Physics is a component of the Physics Suite--a collection of materials created by a group of educational reformers known as the Activity Based Physics Group. The Physics Suite contains a broad array of curricular materials that are based on physics education research, including:

      Understanding Physics, by Cummings, Laws, Redish and Cooney (an introductory textbook based on the best-selling text by Halliday/Resnick/Walker) RealTime Physics Laboratory Modules Physics by Inquiry (intended for use in a workshop setting) Interactive Lecture Demonstration Tutorials in Introductory Physics Activity Based Tutorials (designed primarily for use in recitations)

    • Auditory Cortex Basal Activity Modulates Cochlear Responses in Chinchillas

      PubMed Central

      León, Alex; Elgueda, Diego; Silva, María A.; Hamamé, Carlos M.; Delano, Paul H.

      2012-01-01

      Background The auditory efferent system has unique neuroanatomical pathways that connect the cerebral cortex with sensory receptor cells. Pyramidal neurons located in layers V and VI of the primary auditory cortex constitute descending projections to the thalamus, inferior colliculus, and even directly to the superior olivary complex and to the cochlear nucleus. Efferent pathways are connected to the cochlear receptor by the olivocochlear system, which innervates outer hair cells and auditory nerve fibers. The functional role of the cortico-olivocochlear efferent system remains debated. We hypothesized that auditory cortex basal activity modulates cochlear and auditory-nerve afferent responses through the efferent system. Methodology/Principal Findings Cochlear microphonics (CM), auditory-nerve compound action potentials (CAP) and auditory cortex evoked potentials (ACEP) were recorded in twenty anesthetized chinchillas, before, during and after auditory cortex deactivation by two methods: lidocaine microinjections or cortical cooling with cryoloops. Auditory cortex deactivation induced a transient reduction in ACEP amplitudes in fifteen animals (deactivation experiments) and a permanent reduction in five chinchillas (lesion experiments). We found significant changes in the amplitude of CM in both types of experiments, being the most common effect a CM decrease found in fifteen animals. Concomitantly to CM amplitude changes, we found CAP increases in seven chinchillas and CAP reductions in thirteen animals. Although ACEP amplitudes were completely recovered after ninety minutes in deactivation experiments, only partial recovery was observed in the magnitudes of cochlear responses. Conclusions/Significance These results show that blocking ongoing auditory cortex activity modulates CM and CAP responses, demonstrating that cortico-olivocochlear circuits regulate auditory nerve and cochlear responses through a basal efferent tone. The diversity of the obtained effects

    • MCT SWIR modules for passive and active imaging applications

      NASA Astrophysics Data System (ADS)

      Breiter, R.; Benecke, M.; Eich, D.; Figgemeier, H.; Weber, A.; Wendler, J.; Sieck, A.

      2016-05-01

      Based on AIM's state-of-the-art MCT IR technology, detector modules for the SWIR spectral range have been developed, fabricated and characterized. While LPE grown MCT FPAs with extended 2.5μm cut-off have been fabricated and integrated also MBE grown MCT on GaAs is considered for future production. Two imaging applications have been in focus operating either in passive mode by making use of e.g. the night glow, or in active mode by laser illumination for gated viewing. Dedicated readout integrated circuits (ROIC), realized in 0.18μm Si-CMOS technology providing the required functionality for passive imaging and gated imaging, have been designed and implemented. For both designs a 640x512 15μm pitch format was chosen. The FPAs are integrated in compact dewar cooler configurations using AIM's split linear coolers. A command and control electronics (CCE) provides supply voltages, biasing, clocks, control and video digitization for easy system interfacing. For imaging under low-light conditions a low-noise 640x512 15μm pitch ROIC with CTIA input stages and correlated double sampling was designed. The ROIC provides rolling shutter and snapshot integration. To reduce size, weight, power and cost (SWaP-C) a 640x512 format detector in a 10μm pitch is under development. The module makes use of the extended SWIR spectral cut-off up to 2.5μm. To be used for active gated-viewing operation SWIR MCT avalanche photodiodes have been implemented and characterized on FPA level in a 640x512 15μm pitch format. The specific ROIC provides also the necessary functions for range gate control and triggering by the laser illumination. First lab and field tests of a gated viewing demonstrator have been carried out. The paper will present the development status and performance results of AIM's MCT based SWIR Modules for imaging applications.

    • A human phospholipid phosphatase activated by a transmembrane control module[S

      PubMed Central

      Halaszovich, Christian R.; Leitner, Michael G.; Mavrantoni, Angeliki; Le, Audrey; Frezza, Ludivine; Feuer, Anja; Schreiber, Daniela N.; Villalba-Galea, Carlos A.; Oliver, Dominik

      2012-01-01

      In voltage-sensitive phosphatases (VSPs), a transmembrane voltage sensor domain (VSD) controls an intracellular phosphoinositide phosphatase domain, thereby enabling immediate initiation of intracellular signals by membrane depolarization. The existence of such a mechanism in mammals has remained elusive, despite the presence of VSP-homologous proteins in mammalian cells, in particular in sperm precursor cells. Here we demonstrate activation of a human VSP (hVSP1/TPIP) by an intramolecular switch. By engineering a chimeric hVSP1 with enhanced plasma membrane targeting containing the VSD of a prototypic invertebrate VSP, we show that hVSP1 is a phosphoinositide-5-phosphatase whose predominant substrate is PI(4,5)P2. In the chimera, enzymatic activity is controlled by membrane potential via hVSP1’s endogenous phosphoinositide binding motif. These findings suggest that the endogenous VSD of hVSP1 is a control module that initiates signaling through the phosphatase domain and indicate a role for VSP-mediated phosphoinositide signaling in mammals. PMID:22896666

  1. Caenorhabditis elegans glia modulate neuronal activity and behavior

    PubMed Central

    Stout Jr., Randy F.; Verkhratsky, Alexei; Parpura, Vladimir

    2014-01-01

    Glial cells of Caenorhabditis elegans can modulate neuronal activity and behavior, which is the focus of this review. Initially, we provide an overview of neuroglial evolution, making a comparison between C. elegans glia and their genealogical counterparts. What follows is a brief discussion on C. elegans glia characteristics in terms of their exact numbers, germ layers origin, their necessity for proper development of sensory organs, and lack of their need for neuronal survival. The more specific roles that various glial cells have on neuron-based activity/behavior are succinctly presented. The cephalic sheath glia are important for development, maintenance and activity of central synapses, whereas the amphid glia seem to set the tone of sensory synapses; these glial cell types are ectoderm-derived. Mesoderm-derived Glial-Like cells in the nerve Ring (GLRs) appear to be a part of the circuit for production of motor movement of the worm anterior. Finally, we discuss tools and approaches utilized in studying C. elegans glia, which are assets available for this animal, making it an appealing model, not only in neurosciences, but in biology in general. PMID:24672428

  2. D-Limonene modulates T lymphocyte activity and viability.

    PubMed

    Lappas, Courtney M; Lappas, Nicholas T

    2012-09-01

    d-Limonene, a cyclic terpene that is a major component of several plant essential oils, is used widely as an additive in perfumes, soaps, foods and beverages, and has also been shown to possess chemopreventative and chemotherapeutic activity. A limited number of studies have been conducted investigating the effect of d-limonene on immune system function. We show that d-limonene and its metabolites limonene-1-2-diol and perillic acid inhibit the production by CD3(+)CD4(+) T cells of IFN-γ, IL-2, TNF-α, IL-4 and IL-13, and the production by CD3(+)CD8(+) T cells of IFN-γ, IL-2, and TNF-α. Additionally, the upregulation of CD25, CD69 and CD40L by activated T lymphocytes is modulated by d-limonene, limonene-1-2-diol and perillic acid treatment. Furthermore, high concentrations of d-limonene, limonene-1-2-diol and perillic acid induce T lymphocyte cell death. These data suggest that d-limonene possesses immunomodulatory activity that must be considered when utilizing the compound for therapeutic or commercial purposes. PMID:23059811

  3. Caenorhabditis elegans glia modulate neuronal activity and behavior.

    PubMed

    Stout, Randy F; Verkhratsky, Alexei; Parpura, Vladimir

    2014-01-01

    Glial cells of Caenorhabditis elegans can modulate neuronal activity and behavior, which is the focus of this review. Initially, we provide an overview of neuroglial evolution, making a comparison between C. elegans glia and their genealogical counterparts. What follows is a brief discussion on C. elegans glia characteristics in terms of their exact numbers, germ layers origin, their necessity for proper development of sensory organs, and lack of their need for neuronal survival. The more specific roles that various glial cells have on neuron-based activity/behavior are succinctly presented. The cephalic sheath glia are important for development, maintenance and activity of central synapses, whereas the amphid glia seem to set the tone of sensory synapses; these glial cell types are ectoderm-derived. Mesoderm-derived Glial-Like cells in the nerve Ring (GLRs) appear to be a part of the circuit for production of motor movement of the worm anterior. Finally, we discuss tools and approaches utilized in studying C. elegans glia, which are assets available for this animal, making it an appealing model, not only in neurosciences, but in biology in general. PMID:24672428

  4. Cytosolic Hsp60 Can Modulate Proteasome Activity in Yeast*

    PubMed Central

    Kalderon, Bella; Kogan, Gleb; Bubis, Ettel; Pines, Ophry

    2015-01-01

    Hsp60, an essential oligomeric molecular mitochondrial chaperone, has been subject to rigorous basic and clinical research. With yeast as a model system, we provide evidence for the ability of cytosolic yHsp60 to inhibit the yeast proteasome. (i) Following biological turnover of murine Bax (a proteasome substrate), we show that co-expression of cytosolic yHsp60 stabilizes Bax, enhances its association with mitochondria, and enhances its killing capacity. (ii) Expression of yHsp60 in the yeast cytosol (yHsp60c) inhibits degradation of a cytosolic protein ΔMTS-Aco1 tagged with the degron SL17 (a ubiquitin-proteasome substrate). (iii) Conditions under which Hsp60 accumulates in the cytosol (elevated Hsp60c or growth at 37 °C) correlate with reduced 20 S peptidase activity in proteasomes purified from cell extracts. (iv) Elevated yHsp60 in the cytosol correlate with accumulation of polyubiquitinated proteins. (v) According to 20 S proteasome pulldown experiments, Hsp60 is physically associated with proteasomes in extracts of cells expressing Hsp60c or grown at 37 °C. Even mutant Hsp60 proteins, lacking chaperone activity, were still capable of proteasome inhibition. The results support the hypothesis that localization of Hsp60 to the cytosol may modulate proteasome activity according to cell need. PMID:25525272

  5. Helicobacter pylori antigens as potential modulators of lymphocytes' cytotoxic activity.

    PubMed

    Rudnicka, Karolina; Włodarczyk, Marcin; Moran, Anthony P; Rechciński, Tomasz; Miszczyk, Eliza; Matusiak, Agnieszka; Szczęsna, Ewelina; Walencka, Maria; Rudnicka, Wiesława; Chmiela, Magdalena

    2012-01-01

    Helicobacter pylori (H.p) colonizes human gastric mucosa and causes gastric and duodenal ulcer disease or gastric cancer. Various H.p compounds may modulate the host immune response in regards to tolerance of the infection or disease development. The aim of this study was to determine whether H.p lipopolysaccharide (LPS) and glycine acid extract antigens (GE) or E. coli LPS influence the cytotoxic activity of peripheral blood lymphocytes from H.p infected - H.p (+) or uninfected - H.p (-) individuals, in the presence or absence of exogenous interleukin (IL)12. Individual H.p status was defined by the urea breath test. Lymphocytes, stimulated or not with H.p, and control antigens, with or without IL-12, were used as effector cells and epithelial HeLa cells as targets. The cytotoxicity of lymphocytes was expressed as the percentage of dead target cells unable to reduce tetrazolium salt. The supernatants from HeLa/lymphocyte cultures were used for detection of the cellular cytotoxicity markers granzyme B and caspase 8. The natural cytotoxic activity of lymphocytes from H.p (+) was less than that of H.p (-) donors. This may have been due to fewer natural killer cells of CD3(-) CD56(+) Nkp46(+) phenotype in H.p (+) in comparison to H.p (-) subjects. H.p GE and standard E. coli LPS enhanced the cytotoxicity of lymphocytes towards target cells whereas H.p LPS downregulated this activity. The decrease in lymphocyte cytotoxicity in response to H.p LPS correlated with a lack of IL-2 and IL-12 production, inhibition of interferon-γ production, and low IL-10 secretion by mononuclear leukocytes. IL-12 significantly enhanced the natural as well as H.p LPS and H.p GE driven cytotoxic capacity of lymphocytes. In conclusion, H.p LPS may negatively modulate natural cytotoxic activity and cytokine secretion by immunocompetent cells and thus be involved in the maintenance of infection and development of gastric pathologies. PMID:22040089

  6. Influence of acetylcholinesterase immobilization on the photoluminescence properties of mesoporous silicon surface

    NASA Astrophysics Data System (ADS)

    Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

    2014-07-01

    Acetylcholinesterase immobilized p-type porous silicon surface was prepared by covalent attachment. The immobilization procedure was based on support surface chemical oxidation, silanization, surface activation with cyanuric chloride and finally covalent attachment of free enzyme on the cyanuric chloride activated porous silicon surface. Different pore diameter of porous silicon samples were prepared by electrochemical etching in HF based electrolyte solution and appropriate sample was selected suitable for enzyme immobilization with maximum trapping ability. The surface modification was studied through field emission scanning electron microscope, EDS, FT-IR analysis, and photoluminescence measurement by utilizing the fluctuation in the photoluminescence of virgin and enzyme immobilized porous silicon surface. Porous silicon showed strong photoluminescence with maximum emission at 643 nm and immobilization of acetylcholinesterase on porous silicon surface cause considerable increment on the photoluminescence of porous silicon material while acetylcholinesterase free counterpart did not exhibit any fluorescence in the range of 635-670 nm. The activities of the free and immobilized enzymes were evaluated by spectrophotometric method by using neostigmine methylsulfate as standard enzyme inhibitor. The immobilized enzyme exhibited considerable response toward neostigmine methylsulfate in a dose dependent manner comparable with that of its free counterpart alongside enhanced stability, easy separation from the reaction media and significant saving of enzyme. It was believed that immobilized enzyme can be exploited in organic and biomolecule synthesis possessing technical and economical prestige over free enzyme and prominence of easy separation from the reaction mixture.

  7. Temperature and pressure adaptation of the binding site of acetylcholinesterase.

    PubMed

    Hochachka, P W

    1974-12-01

    1. Studies with a carbon substrate analogue, 3,3-dimethylbutyl acetate, indicate that the hydrophobic contribution to binding at the anionic site of acetylcholinesterase is strongly disrupted at low temperatures and high pressures. 2. Animals living in different physical environments circumvent this problem by adjusting the enthalpic and entropic contributions to binding. 3. An extreme example of this adaptational strategy is supplied by brain acetylcholinesterase extracted from an abyssal fish living at 2 degrees C and up to several hundred atmospheres of pressure. This acetylcholinesterase appears to have a smaller hydrophobic binding region in the anionic site, playing a measurably decreased role in ligand binding. PMID:4462739

  8. Star Power: Providing for the Gifted & Talented. Module 5. Enrichment Activities for the Gifted/Talented.

    ERIC Educational Resources Information Center

    Mallis, Jackie; Gilman, Sharlene

    The document presents Module 5, enrichment activities for the gifted/talented, of the Star Power modules developed for school personnel who have an interest in or a need to explore the area of gifted and talented education. It is explained in an introductory section that the modules can be used for independent study, for small group interaction,…

  9. COMPARISON OF THE RELATIVE INHIBITION OF ACETYLCHOLINESTERASE AND NEUROPATHY TARGET ESTERASE IN RATS AND HENS GIVEN CHOLINESTERASE INHIBITORS

    EPA Science Inventory

    Inhibition of neuropathy target esterase (NTE, neurotoxic esterase) and acetylcholinesterase (AME) activities was compared in brain and spinal cords of adult. hile Leghorn hens and adult male Long Evans rats 4-48 hr after administration of tri-ortho-tolyl phosphate (TOTP po, 50-5...

  10. Some enzymatic properties of brain Acetylcholinesterase from bluegill and channel catfish

    USGS Publications Warehouse

    Hogan, James W.; Knowles, Charles O.

    1968-01-01

    Using a manometric technique an acetylcholinesterase (EC 3.1.1.7, acetylcholine acetyl-hydrolase) was demonstrated in brain tissue from the bluegill, Lepomis macrochirus Rafinesque, and the channel catfish, Ictalurus punctatus (Walbaum). The activities were 19 and 37 μmoles acetylcholine hydrolyzed/milligram protein per hour for the bluegill and channel catfish enzymes, respectively. The optimum substrate concentration for the hydrolysis of acetylcholine was 10 mMfor the enzymes from both species. Generally, the catfish acetylcholinesterase was somewhat more susceptible than the bluegill to the inhibitors tested; however, the bluegill enzyme was more susceptible to inhibition by malathion and malaoxon.

  11. Inhibition of acetylcholinesterase by 14 achiral and five chiral imidazole derivates.

    PubMed

    Kovárová, Markéta; Komers, Karel; Stepánková, Sárka; Cegan, Alexander

    2010-08-01

    Homological series of 14 achiral derivates and series of five chiral derivates of imidazole were tested in vitro as inhibitors of hydrolysis of acetylcholine using enzyme preparation of acetylcholinesterase from electric eel. The batch stirred reactor at 25 degrees C, pH 8 (phosphate buffer), ionic strength 0.11 M and catalytic activity of the enzyme preparation 0.14 U ml(-1) of the reaction mixture were used. The temporal dependences of actual concentrations of acetylcholine, choline and acetic acid were determined by an original HPLC method. For all used inhibitors, these time dependences conform with the probability of more than 90% to the model of competitive irreversible inhibition. All kinetic constants including k(3) defining the rate of inhibition (0.38-5.3M(-1)s(-1)) and qualified estimation of the absolute acetylcholinesterase concentration in the reaction mixture (40-110 nM) were determined. PMID:20335028

  12. Materials and Process Activities for NASA's Composite Crew Module

    NASA Technical Reports Server (NTRS)

    Polis, Daniel L.

    2012-01-01

    In January 2007, the NASA Administrator and Associate Administrator for the Exploration Systems Mission Directorate chartered the NASA Engineering and Safety Center (NESC) to design, build, and test a full-scale Composite Crew Module (CCM). The overall goal of the CCM project was to develop a team from the NASA family with hands-on experience in composite design, manufacturing, and testing in anticipation of future space exploration systems being made of composite materials. The CCM project was planned to run concurrently with the Orion project s baseline metallic design within the Constellation Program so that features could be compared and discussed without inducing risk to the overall Program. The materials and process activities were prioritized based on a rapid prototype approach. This approach focused developmental activities on design details with greater risk and uncertainty, such as out-of-autoclave joining, over some of the more traditional lamina and laminate building block levels. While process development and associated building block testing were performed, several anomalies were still observed at the full-scale level due to interactions between process robustness and manufacturing scale-up. This paper describes the process anomalies that were encountered during the CCM development and the subsequent root cause investigations that led to the final design solutions. These investigations highlight the importance of full-scale developmental work early in the schedule of a complex composite design/build project.

  13. Active Desiccant Dehumidification Module Integration with Rooftop Packaged HVAC

    SciTech Connect

    Fischer, J

    2002-04-17

    This report summarizes a research and development program that produced a stand-alone active desiccant module (ADM) that can be easily integrated with new or existing packaged cooling equipment. The program also produced a fully integrated hybrid system, combining the active desiccant section with a conventional direct expansion air-conditioning unit, that resulted in a compact, low-cost, energy-efficient end product. Based upon the results of this investigation, both systems were determined to be highly viable products for commercialization. Major challenges--including wheel development, compact packaging, regeneration burner development, control optimization, and low-cost design--were all successfully addressed by the final prototypes produced and tested as part of this program. Extensive laboratory testing was completed in the SEMCO laboratory for each of the two ADM system approaches. This testing confirmed the performance of the ADM systems to be attractive compared with that of alternate approaches currently used to precondition outdoor air, where a return air path is not readily available for passive desiccant recovery or where first cost is the primary design criterion. Photographs, schematics, and performance maps are provided for the ADM systems that were developed; and many of the control advantages are discussed. Based upon the positive results of this research and development program, field tests are under way for fully instrumented pilot installations of ADM systems in both a hotel/motel and a restaurant.

  14. Modulation of Group I Ribozyme Activity by Cationic Porphyrins

    PubMed Central

    Matsumura, Shigeyoshi; Ito, Tatsunobu; Tanaka, Takahiro; Furuta, Hiroyuki; Ikawa, Yoshiya

    2015-01-01

    The effects of cationic porphyrins on the catalytic activities of four group I ribozymes were investigated. A cationic porphyrin possessing four pyridinium moieties (pPyP) inhibited two group IC3 ribozymes (Syn Rz and Azo Rz) and a group IC1 ribozyme (Tet Rz). In the case of a group IA2 ribozyme (Td Rz), however, pPyP served not only as an inhibitor but also as an activator, and the effects of pPyP were dependent on its concentration. To analyze the structural and electronic factors determining the effects of pPyP on group I ribozymes, three cationic porphyrins (pPyNCP, pPyF4P, and TMPyP) were also examined. As interactions between small organic molecules and nucleic acids are attractive and important issues in biochemistry and biotechnology, this study contributes to the development of porphyrin-based molecules that can modulate functions of structured RNA molecules. PMID:25811638

  15. Physiological mechanisms for the modulation of pannexin 1 channel activity

    PubMed Central

    Sandilos, Joanna K; Bayliss, Douglas A

    2012-01-01

    It is widely recognized that ATP, along with other nucleotides, subserves important intercellular signalling processes. Among various nucleotide release mechanisms, the relatively recently identified pannexin 1 (Panx1) channel is gaining prominence by virtue of its ability to support nucleotide permeation and release in a variety of different tissues. Here, we review recent advances in our understanding of the factors that control Panx1 channel activity. By using electrophysiological and biochemical approaches, diverse mechanisms that dynamically regulate Panx1 channel function have been identified in various settings; these include, among others, activation by caspase-mediated channel cleavage in apoptotic immune cells, by G protein-coupled receptors in vascular smooth muscle, by low oxygen tension in erythrocytes and neurons, by high extracellular K+ in various cell types and by stretch/strain in airway epithelia. Delineating the distinct mechanisms of Panx1 modulation that prevail in different physiological contexts provides the possibility that these channels, and ATP release, could ultimately be targeted in a context-dependent manner. PMID:23070703

  16. Molecular Dynamics of Mouse Acetylcholinesterase Complexed with Huperzine A

    SciTech Connect

    Tara, Sylvia; Helms, Volkhard H.; Straatsma, TP; Mccammon, J Andrew A.

    1999-03-16

    Two molecular dynamics simulations were performed for a modeled complex of mouse acetylcholinesterase liganded with huperzine A (HupA). Analysis of these simulations shows that HupA shifts in the active site toward Tyr 337 and Phe 338, and that several residues in the active site area reach out to make hydrogen bonds with the inhibitor. Rapid fluctuations of the gorge width are observed, ranging from widths that allow substrate access to the active site, to pinched structures that do not allow access of molecules as small as water. Additional openings or channels to the active site are found. One opening is formed in the side wall of the active site gorge by residues Val 73, Asp 74, Thr 83, Glu 84, and Asn 87. Another opening is formed at the base of the gorge by residues Trp 86, Val 132, Glu 202, Gly 448, and Ile 451. Both of these openings have been observed separately in the Torpedo californica form of the enzyme. These channels could allow transport of waters and ions to and from the bulk solution.

  17. Multiplicative and Additive Modulation of Neuronal Tuning with Population Activity Affects Encoded Information.

    PubMed

    Arandia-Romero, Iñigo; Tanabe, Seiji; Drugowitsch, Jan; Kohn, Adam; Moreno-Bote, Rubén

    2016-03-16

    Numerous studies have shown that neuronal responses are modulated by stimulus properties and also by the state of the local network. However, little is known about how activity fluctuations of neuronal populations modulate the sensory tuning of cells and affect their encoded information. We found that fluctuations in ongoing and stimulus-evoked population activity in primate visual cortex modulate the tuning of neurons in a multiplicative and additive manner. While distributed on a continuum, neurons with stronger multiplicative effects tended to have less additive modulation and vice versa. The information encoded by multiplicatively modulated neurons increased with greater population activity, while that of additively modulated neurons decreased. These effects offset each other so that population activity had little effect on total information. Our results thus suggest that intrinsic activity fluctuations may act as a "traffic light" that determines which subset of neurons is most informative. PMID:26924437

  18. Coincident Helminth Infection Modulates Systemic Inflammation and Immune Activation in Active Pulmonary Tuberculosis

    PubMed Central

    George, Parakkal Jovvian; Kumar, Nathella Pavan; Sridhar, Rathinam; Hanna, Luke E.; Nair, Dina; Banurekha, Vaithilingam V.; Nutman, Thomas B.; Babu, Subash

    2014-01-01

    Background Helminth infections are known to modulate innate and adaptive immune responses in active and latent tuberculosis (TB). However, the role of helminth infections in modulating responses associated with inflammation and immune activation (reflecting disease activity and/or severity) in TB is not known. Methodology We measured markers of inflammation and immune activation in active pulmonary TB individuals (ATB) with co-incidental Strongyloides stercoralis (Ss) infection. These included systemic levels of acute phase proteins, matrix metalloproteinases and their endogenous inhibitors and immune activation markers. As a control, we measured the systemic levels of the same molecules in TB-uninfected individuals (NTB) with or without Ss infection. Principal Findings Our data confirm that ATB is associated with elevated levels of the various measured molecules when compared to those seen in NTB. Our data also reveal that co-incident Ss infection in ATB individuals is associated with significantly decreased circulating levels of acute phase proteins, matrix metalloproteinases, tissue inhibitors of matrix metalloproteinases as well as the systemic immune activation markers, sCD14 and sCD163. These changes are specific to ATB since they are absent in NTB individuals with Ss infection. Conclusions Our data therefore reveal a profound effect of Ss infection on the markers associated with TB disease activity and severity and indicate that co-incidental helminth infections might dampen the severity of TB disease. PMID:25375117

  19. Antileishmanial Activity of the Estrogen Receptor Modulator Raloxifene

    PubMed Central

    Reimão, Juliana Q.; Miguel, Danilo C.; Taniwaki, Noemi N.; Trinconi, Cristiana T.; Yokoyama-Yasunaka, Jenicer K. U.; Uliana, Silvia R. B.

    2014-01-01

    Background The treatment of leishmaniasis relies mostly on parenteral drugs with potentially serious adverse effects. Additionally, parasite resistance in the treatment of leishmaniasis has been demonstrated for the majority of drugs available, making the search for more effective and less toxic drugs and treatment regimens a priority for the control of leishmaniasis. The aims of this study were to evaluate the antileishmanial activity of raloxifene in vitro and in vivo and to investigate its mechanism of action against Leishmania amazonensis. Methodology/Principal Findings Raloxifene was shown to possess antileishmanial activity in vitro against several species with EC50 values ranging from 30.2 to 38.0 µM against promastigotes and from 8.8 to 16.2 µM against intracellular amastigotes. Raloxifene's mechanism of action was investigated through transmission electron microscopy and labeling with propidium iodide, DiSBAC2(3), rhodamine 123 and monodansylcadaverine. Microscopic examinations showed that raloxifene treated parasites displayed autophagosomes and mitochondrial damage while the plasma membrane remained continuous. Nonetheless, plasma membrane potential was rapidly altered upon raloxifene treatment with initial hyperpolarization followed by depolarization. Loss of mitochondrial membrane potential was also verified. Treatment of L. amazonensis – infected BALB/c mice with raloxifene led to significant decrease in lesion size and parasite burden. Conclusions/Significance The results of this work extend the investigation of selective estrogen receptor modulators as potential candidates for leishmaniasis treatment. The antileishmanial activity of raloxifene was demonstrated in vitro and in vivo. Raloxifene produces functional disorder on the plasma membrane of L. amazonensis promastigotes and leads to functional and morphological disruption of mitochondria, which culminate in cell death. PMID:24810565

  20. Enhancer-specific modulation of E protein activity.

    PubMed

    Markus, Maurice; Du, Zhimei; Benezra, Robert

    2002-02-22

    Homodimeric complexes of members of the E protein family of basic helix-loop-helix (bHLH) transcription factors are important for tissue-specific activation of genes in B lymphocytes (Bain, G., Gruenwald, S., and Murre, C. (1993) Mol. Cell Biol. 13, 3522-3529; Shen, C. P., and Kadesch, T. (1995) Mol. Cell Biol. 15, 4518-4524; Jacobs, Y., et al. (1994) Mol. Cell Biol. 14, 4087-4096; Wilson, R. B., et al. (1991) Mol. Cell Biol. 11, 6185-6191). These homodimers, however, have little activity on myogenic enhancers (Weintraub, H., Genetta, T., and Kadesch, T. (1994) Genes Dev. 8, 2203-2211). We report here the identification of a novel cis-acting transcriptional repression domain in the E protein family of bHLH transcription factors. This domain, the Rep domain, is present in each of the known vertebrate E proteins. Extensive mapping analysis demonstrates that this domain is an acidic region of 30 amino acids with a predicted loop structure. Fusion studies indicate that the Rep domain can repress both of the E protein transactivation domains (AD1 and AD2). Physiologically, the Rep domain plays a key role in maintaining E protein homodimers in an inactive state on myogenic enhancers. In addition, we demonstrate that Rep domain mediated repression of AD1 is a necessary for the function of MyoD-E protein heterodimeric complexes. These studies demonstrate that the Rep domain is important for modulating the transcriptional activity of E proteins and provide key insights into both the selectivity and mechanism of action of E protein containing bHLH protein complexes. PMID:11724804

  1. Platelet activation and apoptosis modulate monocyte inflammatory responses in dengue

    PubMed Central

    Hottz, Eugenio D.; Medeiros-de-Moraes, Isabel M.; Vieira-de-Abreu, Adriana; de Assis, Edson F.; Vals-de-Souza, Rogério; Castro-Faria-Neto, Hugo C.; Weyrich, Andrew S.; Zimmerman, Guy A.; Bozza, Fernando A.; Bozza, Patrícia T.

    2014-01-01

    Background Dengue is the most prevalent human arbovirus disease in the world. Dengue infection has a large spectrum of clinical manifestations from self-limited febrile illness to severe syndromes accompanied by bleeding and shock. Thrombocytopenia and vascular leak with altered cytokine profiles in plasma are features of severe dengue. Although monocytes have been recognized as important sources of cytokines in dengue, the contributions of platelet-monocyte interactions to inflammatory responses in dengue have not been addressed. Patients/Methods Patients with dengue were investigated for platelet-monocyte aggregate formation and markers of monocyte activation. Platelet-induced cytokine responses by monocytes and underlying mechanisms were also investigated in vitro. Results We observed increased levels of platelet-monocyte aggregates in blood samples from patients with dengue, especially patients with thrombocytopenia and increased vascular permeability. Moreover, the exposure of monocytes from healthy volunteers to platelets from patients with dengue induced the secretion of the cytokines IL-1β, IL-8, IL-10 and MCP-1, while the exposure to platelets from healthy volunteers only induced the secretion of MCP-1. In addition to the well-established modulation of monocyte cytokine responses by activated platelets through P-selectin binding, we found that interaction of monocytes with apoptotic platelets mediate IL-10 secretion through phosphatidylserine recognition in platelet-monocyte aggregates. Moreover, IL-10 secretion required platelet-monocyte contact but not phagocytosis. Conclusions Together, our results demonstrate that activated and apoptotic platelets aggregate with monocytes during dengue infection and signal specific cytokine responses that may contribute to the pathogenesis of dengue. PMID:25015827

  2. Rare earth activated yttrium aluminate phosphors with modulated luminescence.

    PubMed

    Muresan, L E; Popovici, E J; Perhaita, I; Indrea, E; Oro, J; Casan Pastor, N

    2016-06-01

    Yttrium aluminate (Y3 A5 O12 ) was doped with different rare earth ions (i.e. Gd(3+) , Ce(3+) , Eu(3+) and/or Tb(3+) ) in order to obtain phosphors (YAG:RE) with general formula,Y3-x-a Gdx REa Al5 O12 (x = 0; 1.485; 2.97 and a = 0.03). The synthesis of the phosphor samples was done using the simultaneous addition of reagents technique. This study reveals new aspects regarding the influence of different activator ions on the morpho-structural and luminescent characteristics of garnet type phosphor. All YAG:RE phosphors are well crystallized powders containing a cubic-Y3 Al5 O12 phase as major component along with monoclinic-Y4 Al2 O9 and orthorhombic-YAlO3 phases as the impurity. The crystallites dimensions of YAG:RE phosphors vary between 38 nm and 88 nm, while the unit cell slowly increase as the ionic radius of the activator increases. Under UV excitation, YAG:Ce exhibits yellow emission due to electron transition in Ce(3+) from the 5d level to the ground state levels ((2) F5/2 , (2) F7/2 ). The emission intensity of Ce(3+) is enhanced in the presence of the Tb(3+) ions and is decreased in the presence of Eu(3+) ions due to some radiative or non-radiative processes that take place between activator ions. By varying the rare earth ions, the emission colour can be modulated from green to white and red. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26553167

  3. Active space debris removal by a hybrid propulsion module

    NASA Astrophysics Data System (ADS)

    DeLuca, L. T.; Bernelli, F.; Maggi, F.; Tadini, P.; Pardini, C.; Anselmo, L.; Grassi, M.; Pavarin, D.; Francesconi, A.; Branz, F.; Chiesa, S.; Viola, N.; Bonnal, C.; Trushlyakov, V.; Belokonov, I.

    2013-10-01

    During the last 40 years, the mass of the artificial objects in orbit increased quite steadily at the rate of about 145 metric tons annually, leading to a total tally of approximately 7000 metric tons. Now, most of the cross-sectional area and mass (97% in LEO) is concentrated in about 4600 intact objects, i.e. abandoned spacecraft and rocket bodies, plus a further 1000 operational spacecraft. Simulations and parametric analyses have shown that the most efficient and effective way to prevent the outbreak of a long-term exponential growth of the catalogued debris population would be to remove enough cross-sectional area and mass from densely populated orbits. In practice, according to the most recent NASA results, the active yearly removal of approximately 0.1% of the abandoned intact objects would be sufficient to stabilize the catalogued debris in low Earth orbit, together with the worldwide adoption of mitigation measures. The candidate targets for removal would have typical masses between 500 and 1000 kg, in the case of spacecraft, and of more than 1000 kg, in the case of rocket upper stages. Current data suggest that optimal active debris removal missions should be carried out in a few critical altitude-inclination bands. This paper deals with the feasibility study of a mission in which the debris is removed by using a hybrid propulsion module as propulsion unit. Specifically, the engine is transferred from a servicing platform to the debris target by a robotic arm so to perform a controlled disposal. Hybrid rocket technology for de-orbiting applications is considered a valuable option due to high specific impulse, intrinsic safety, thrust throttle ability, low environmental impact and reduced operating costs. Typically, in hybrid rockets a gaseous or liquid oxidizer is injected into the combustion chamber along the axial direction to burn a solid fuel. However, the use of tangential injection on a solid grain Pancake Geometry allows for more compact design of

  4. Current acetylcholinesterase-inhibitors: a neuroinformatics perspective.

    PubMed

    Shaikh, Sibhghatulla; Verma, Anupriya; Siddiqui, Saimeen; Ahmad, Syed S; Rizvi, Syed M D; Shakil, Shazi; Biswas, Deboshree; Singh, Divya; Siddiqui, Mohmmad H; Shakil, Shahnawaz; Tabrez, Shams; Kamal, Mohammad A

    2014-04-01

    This review presents a concise update on the inhibitors of the neuroenzyme, acetylcholinesterase (AChE; EC 3.1.1.7). AChE is a serine protease, which hydrolyses the neurotransmitter, acetylcholine into acetate and choline thereby terminating neurotransmission. Molecular interactions (mode of binding to the target enzyme), clinical applications and limitations have been summarized for each of the inhibitors discussed. Traditional inhibitors (e.g. physostigmine, tacrine, donepezil, rivastigmine etc.) as well as novel inhibitors like various physostigmine-derivatives have been covered. This is followed by a short glimpse on inhibitors derived from nature (e.g. Huperzine A and B, Galangin). Also, a discussion on 'hybrid of pre-existing drugs' has been incorporated. Furthermore, current status of therapeutic applications of AChEinhibitors has also been summarized. PMID:24059296

  5. Promoting Active Learning with Cases and Instructional Modules.

    ERIC Educational Resources Information Center

    Richards, Larry G.; And Others

    1995-01-01

    Proposes the use of cases and instructional modules to teach invention, engineering design, and technology management. Discusses the case method in graduate business education, cases and modules in engineering education, using cases in class, and the development and distribution of cases. Presents examples of using cases about total quality…

  6. Nicotinic modulation of serotonergic activity in the dorsal raphe nucleus.

    PubMed

    Hernandez-Lopez, Salvador; Garduño, Julieta; Mihailescu, Stefan

    2013-01-01

    Cholinergic signaling mediated by nicotinic receptors has been associated to a large number of physiological and behavioral processes such as learning, memory, attention, food-intake and mood disorders. Although it is well established that many nicotinic actions are mediated through an increase in serotonin (5-HT) release, the physiological mechanisms by which nicotine produces these effects are still unclear. The dorsal raphe nucleus (DRN) contains the major amount of 5-HT neurons projecting to different parts of the brain. DRN also contains nicotinic acetylcholine receptors (nAChRs) located at somatic and presynaptic elements. Nicotine produces both inhibitory and excitatory effects on different subpopulations of 5-HT DRN neurons. In this review, we describe the presynaptic and postsynaptic mechanisms by which nicotine increases the excitability of DRN neurons as well as the subtypes of nAChRs involved. We also describe the inhibitory effects of nicotine and the role of 5-HT1A receptors in this effect. These nicotinic actions modulate the activity of different neuronal subpopulations in the DRN, changing the 5-HT tone in the brain areas where these groups of neurons project. Some of the physiological implications of nicotine-induced 5-HT release are discussed. PMID:24021594

  7. Behavioral State Modulates the Activity of Brainstem Sensorimotor Neurons

    PubMed Central

    McArthur, Kimberly L.

    2011-01-01

    Sensorimotor processing must be modulated according to the animal's behavioral state. A previous study demonstrated that motion responses were strongly state dependent in birds. Vestibular eye and head responses were significantly larger and more compensatory during simulated flight, and a flight-specific vestibular tail response was also characterized. In the current study, we investigated the neural substrates for these state-dependent vestibular behaviors by recording extracellularly from neurons in the vestibular nuclear complex and comparing their spontaneous activity and sensory responses during default and simulated flight states. We show that motion-sensitive neurons in the lateral vestibular nucleus are state dependent. Some neurons increased their spontaneous firing rates during flight, though their increased excitability was not reflected in higher sensory gains. However, other neurons exhibited state-dependent gating of sensory inputs, responding to rotational stimuli only during flight. These results demonstrate that vestibular processing in the brainstem is state dependent and lay the foundation for future studies to investigate the synaptic mechanisms responsible for these modifications. PMID:22090497

  8. Sexual Experience Modulates Neuronal Activity in Male Japanese Quail

    PubMed Central

    Can, Adem; Domjan, Michael; Delville, Yvon

    2008-01-01

    After an initial increase, repeated exposure to a particular stimulus or familiarity with an event results in lower immediate early gene expression levels in relevant brain structures. We predicted that similar effects would occur in Japanese quail after repeated sexual experience within brain areas involved in sexual behavior, namely, the medial preoptic nucleus (POM), the bed nucleus of stria terminalis (BST), and the nucleus taeniae of the amygdala (TnA), an avian homolog of medial amygdala. High experience subjects copulated with a female once on each of 16 consecutive days, whereas low experience subjects were allowed to copulate either once or twice. Control subjects were never exposed to a female. High experience subjects were faster to initiate sexual interaction, performed more cloacal contacts, and completed each cloacal contact faster than low experience subjects. Low experience subjects showed an increase in egr-1 (ZENK) expression, an immediate early gene product used as marker of neural activation in birds, in the areas of interest. In contrast, in high experience animals, egr-1 expression in the POM, BST and the periaqueductal gray (PAG) was not different than the level of expression in unmated controls. These results show that experience modulates the level of immediate early gene expression in the case of sexual behavior. Our results also indicate that immediate early gene expression in specific brain areas is not necessarily related to behavioral output, but depends on the behavioral history of the subjects. PMID:17826778

  9. Cucurbitacin E Potently Modulates the Activity of Encephalitogenic Cells.

    PubMed

    Jevtić, Bojan; Djedović, Neda; Stanisavljević, Suzana; Despotović, Jovana; Miljković, Djordje; Timotijević, Gordana

    2016-06-22

    Cucurbitacin E (CucE) is a highly oxidized steroid consisting of a tetracyclic triterpene. It is a member of a Cucurbitacin family of biomolecules that are predominantly found in Cucurbitaceae plants. CucE has already been identified as a potent anti-inflammatory compound. Here, its effects on CD4(+) T helper (Th) cells and macrophages, as the major encephalitogenic cells in the autoimmunity of the central nervous system, were investigated. Production of major pathogenic Th cell cytokines: interferon-gamma and interleukin-17 were inhibited under the influence of CucE. The effects of CucE on CD4(+) T cells were mediated through the modulation of aryl hydrocarbon receptor, STAT3, NFκB, p38 MAPK, and miR-146 signaling. Further, production of nitric oxide and reactive oxygen species, as well as phagocytic ability, were inhibited in macrophages treated with CucE. These results imply that CucE possesses powerful antiencephalitogenic activity. PMID:27225664

  10. Extracellular magnesium and calcium blockers modulate macrophage activity.

    PubMed

    Libako, Patrycja; Nowacki, Wojciech; Castiglioni, Sara; Mazur, Andrzej; Maier, Jeanette A M

    2016-03-01

    Magnesium (Mg) possesses anti-inflammatory properties, partly because it antagonizes calcium (Ca) and inhibits L-type Ca channels. Our aim was to determine the effects of different concentrations of extracellular Mg, with or without Ca-channel blockers, in macrophages. A macrophage-like cell line J774.E was cultured in different concentrations of extracellular Mg and exposed to i) the phorbol ester PMA to induce the production of reactive oxygen species ii) lipopolysaccharide to induce the production of pro-inflammatory cytokines, or iii) ovalbumin to study endocytosis. The Ca antagonists verapamil and/or TMB-8 were used to interfere with Ca homeostasis. Different concentrations of extracellular Mg did not impact on endocytosis, while Ca antagonists markedly decreased it. Low extracellular Mg exacerbated, whereas Ca antagonists inhibited, PMA-induced production of free radicals. Ca blockers prevented lipopolysaccharide-induced transcription and release of IL-1β, IL-6 and TNF-α, while extracellular Mg had only a marginal effect. Ca channel inhibitors markedly reduced the activity of J774.E cells, thus underscoring the critical role of Ca in the non-specific immune response, a role which was, in some instances, also modulated by extracellular Mg. PMID:27160489

  11. Transketolase activity modulates glycerol-3-phosphate levels in Escherichia coli.

    PubMed

    Vimala, A; Harinarayanan, R

    2016-04-01

    Transketolase activity provides an important link between the metabolic pathways of glycolysis and pentose phosphate shunt and catalyzes inter-conversions between pentose phosphates and glycolytic intermediates. It is widely conserved in life forms. A genetic screen for suppression of the growth defect of Escherichia coli tktA tktB mutant in LB medium revealed two mutations, one that rendered the glpK expression constitutive and another that inactivated deoB. Characterizing these mutations aided in uncovering the role of ribose-5-P (a transketolase substrate) as an inhibitor of glycerol assimilation and de novo glycerol-3-P synthesis. Using lacZ fusions, we show that ribose-5-P enhances GlpR-mediated repression of the glpFKX operon and inhibits glycerol assimilation. Electrophoretic Mobility Shift Assay (EMSA) showed ribose-5-P made the DNA-GlpR complex less sensitive to the inducer glycerol-3-P. In addition to inhibition of glycerol assimilation, obstruction of ribose-5-P metabolism retards growth from glycerol-3-P limitation. Glucose helps to overcome this limitation through a mechanism involving catabolite repression. To our knowledge, this report is the first to show ribose-5-P can modulate glycerol-3-P concentration in the cell by regulation of glycerol assimilation as well as its de novo synthesis. This regulation could be prevalent in other organisms. PMID:26691989

  12. CD83 Modulates B Cell Activation and Germinal Center Responses.

    PubMed

    Krzyzak, Lena; Seitz, Christine; Urbat, Anne; Hutzler, Stefan; Ostalecki, Christian; Gläsner, Joachim; Hiergeist, Andreas; Gessner, André; Winkler, Thomas H; Steinkasserer, Alexander; Nitschke, Lars

    2016-05-01

    CD83 is a maturation marker for dendritic cells. In the B cell lineage, CD83 is expressed especially on activated B cells and on light zone B cells during the germinal center (GC) reaction. The function of CD83 during GC responses is unclear. CD83(-/-) mice have a strong reduction of CD4(+) T cells, which makes it difficult to analyze a functional role of CD83 on B cells during GC responses. Therefore, in the present study we generated a B cell-specific CD83 conditional knockout (CD83 B-cKO) model. CD83 B-cKO B cells show defective upregulation of MHC class II and CD86 expression and impaired proliferation after different stimuli. Analyses of GC responses after immunization with various Ags revealed a characteristic shift in dark zone and light zone B cell numbers, with an increase of B cells in the dark zone of CD83 B-cKO mice. This effect was not accompanied by alterations in the level of IgG immune responses or by major differences in affinity maturation. However, an enhanced IgE response was observed in CD83 B-cKO mice. Additionally, we observed a strong competitive disadvantage of CD83-cKO B cells in GC responses in mixed bone marrow chimeras. Furthermore, infection of mice with Borrelia burgdorferi revealed a defect in bacterial clearance of CD83 B-cKO mice with a shift toward a Th2 response, indicated by a strong increase in IgE titers. Taken together, our results show that CD83 is important for B cell activation and modulates GC composition and IgE Ab responses in vivo. PMID:26983787

  13. Allergy Enhances Neurogenesis and Modulates Microglial Activation in the Hippocampus

    PubMed Central

    Klein, Barbara; Mrowetz, Heike; Thalhamer, Josef; Scheiblhofer, Sandra; Weiss, Richard; Aigner, Ludwig

    2016-01-01

    Allergies and their characteristic TH2-polarized inflammatory reactions affect a substantial part of the population. Since there is increasing evidence that the immune system modulates plasticity and function of the central nervous system (CNS), we investigated the effects of allergic lung inflammation on the hippocampus—a region of cellular plasticity in the adult brain. The focus of the present study was on microglia, the resident immune cells of the CNS, and on hippocampal neurogenesis, i.e., the generation of new neurons. C57BL/6 mice were sensitized with a clinically relevant allergen derived from timothy grass pollen (Phl p 5). As expected, allergic sensitization induced high serum levels of allergen-specific immunoglobulins (IgG1 and IgE) and of TH2 cytokines (IL-5 and IL-13). Surprisingly, fewer Iba1+ microglia were found in the granular layer (GL) and subgranular zone (SGZ) of the hippocampal dentate gyrus and also the number of Iba1+MHCII+ cells was lower, indicating a reduced microglial surveillance and activation in the hippocampus of allergic mice. Neurogenesis was analyzed by labeling of proliferating cells with bromodeoxyuridine (BrdU) and determining their fate 4 weeks later, and by quantitative analysis of young immature neurons, i.e., cells expressing doublecortin (DCX). The number of DCX+ cells was clearly increased in the allergy animals. Moreover, there were more BrdU+ cells present in the hippocampus of allergic mice, and these newly born cells had differentiated into neurons as indicated by a higher number of BrdU+NeuN+ cells. In summary, allergy led to a reduced microglia presence and activity and to an elevated level of neurogenesis in the hippocampus. This effect was apparently specific to the hippocampus, as we did not observe these alterations in the subventricular zone (SVZ)/olfactory bulb (OB) system, also a region of high cellular plasticity and adult neurogenesis. PMID:27445696

  14. Behavioral activation system modulation on brain activation during appetitive and aversive stimulus processing.

    PubMed

    Barrós-Loscertales, Alfonso; Ventura-Campos, Noelia; Sanjuán-Tomás, Ana; Belloch, Vicente; Parcet, Maria-Antònia; Avila, César

    2010-03-01

    The reinforcement sensitivity theory (RST) proposed the behavioral activation system (BAS) as a neurobehavioral system that is dependent on dopamine-irrigated structures and that mediates the individual differences in sensitivity and reactivity to appetitive stimuli associated with BAS-related personality traits. Theoretical developments propose that high BAS sensitivity is associated with both enhanced appetitive stimuli processing and the diminished processing of aversive stimuli. The objective of this study was to analyze how individual differences in BAS functioning were associated with brain activation during erotic and aversive picture processing while subjects were involved in a simple goal-directed task. Forty-five male participants took part in this study. The task activation results confirm the activation of the reward and punishment brain-related structures while viewing erotic and aversive pictures, respectively. The SR scores show a positive correlation with activation of the left lateral prefrontal cortex, the mesial prefrontal cortex and the right occipital cortex while viewing erotic pictures, and a negative correlation with the right lateral prefrontal cortex and the left occipital cortex while viewing aversive pictures. In summary, the SR scores modulate the activity of the cortical areas in the prefrontal and the occipital cortices that are proposed to modulate the BAS and the BIS-FFFS. PMID:20147458

  15. Behavioral activation system modulation on brain activation during appetitive and aversive stimulus processing

    PubMed Central

    Ventura-Campos, Noelia; Sanjuán-Tomás, Ana; Belloch, Vicente; Parcet, Maria-Antònia; Ávila, César

    2010-01-01

    The reinforcement sensitivity theory (RST) proposed the behavioral activation system (BAS) as a neurobehavioral system that is dependent on dopamine-irrigated structures and that mediates the individual differences in sensitivity and reactivity to appetitive stimuli associated with BAS-related personality traits. Theoretical developments propose that high BAS sensitivity is associated with both enhanced appetitive stimuli processing and the diminished processing of aversive stimuli. The objective of this study was to analyze how individual differences in BAS functioning were associated with brain activation during erotic and aversive picture processing while subjects were involved in a simple goal-directed task. Forty-five male participants took part in this study. The task activation results confirm the activation of the reward and punishment brain-related structures while viewing erotic and aversive pictures, respectively. The SR scores show a positive correlation with activation of the left lateral prefrontal cortex, the mesial prefrontal cortex and the right occipital cortex while viewing erotic pictures, and a negative correlation with the right lateral prefrontal cortex and the left occipital cortex while viewing aversive pictures. In summary, the SR scores modulate the activity of the cortical areas in the prefrontal and the occipital cortices that are proposed to modulate the BAS and the BIS-FFFS. PMID:20147458

  16. Telmisartan Modulates Glial Activation: In Vitro and In Vivo Studies.

    PubMed

    Torika, Nofar; Asraf, Keren; Danon, Abraham; Apte, Ron N; Fleisher-Berkovich, Sigal

    2016-01-01

    The circulating renin-angiotensin system (RAS), including the biologically active angiotensin II, is a fundamental regulatory mechanism of blood pressure conserved through evolution. Angiotensin II components of the RAS have also been identified in the brain. In addition to pro-inflammatory cytokines, neuromodulators, such as angiotensin II can induce (through angiotensin type 1 receptor (AT1R)) some of the inflammatory actions of brain glial cells and influence brain inflammation. Moreover, in Alzheimer's disease (AD) models, where neuroinflammation occurs, increased levels of cortical AT1Rs have been shown. Still, the precise role of RAS in neuroinflammation is not completely clear. The overall aim of the present study was to elucidate the role of RAS in the modulation of glial functions and AD pathology. To reach this goal, the specific aims of the present study were a. to investigate the long term effect of telmisartan (AT1R blocker) on tumor necrosis factor-α (TNF-α), interleukin 1-β (IL1-β) and nitric oxide (NO) release from glial cells. b. to examine the effect of intranasally administered telmisartan on amyloid burden and microglial activation in 5X familial AD (5XFAD) mice. Telmisartan effects in vivo were compared to those of perindopril (angiotensin converting enzyme inhibitor). Long-term-exposure of BV2 microglia to telmisartan significantly decreased lipopolysaccharide (LPS) -induced NO, inducible NO synthase, TNF-α and IL1-β synthesis. The effect of Telmisartan on NO production in BV2 cells was confirmed also in primary neonatal rat glial cells. Intranasal administration of telmisartan (1 mg/kg/day) for up to two months significantly reduced amyloid burden and CD11b expression (a marker for microglia) both in the cortex and hipoccampus of 5XFAD. Based on the current view of RAS and our data, showing reduced amyloid burden and glial activation in the brains of 5XFAD transgenic mice, one may envision potential intervention with the progression of

  17. Telmisartan Modulates Glial Activation: In Vitro and In Vivo Studies

    PubMed Central

    Torika, Nofar; Asraf, Keren; Danon, Abraham; Apte, Ron N.; Fleisher-Berkovich, Sigal

    2016-01-01

    The circulating renin-angiotensin system (RAS), including the biologically active angiotensin II, is a fundamental regulatory mechanism of blood pressure conserved through evolution. Angiotensin II components of the RAS have also been identified in the brain. In addition to pro-inflammatory cytokines, neuromodulators, such as angiotensin II can induce (through angiotensin type 1 receptor (AT1R)) some of the inflammatory actions of brain glial cells and influence brain inflammation. Moreover, in Alzheimer’s disease (AD) models, where neuroinflammation occurs, increased levels of cortical AT1Rs have been shown. Still, the precise role of RAS in neuroinflammation is not completely clear. The overall aim of the present study was to elucidate the role of RAS in the modulation of glial functions and AD pathology. To reach this goal, the specific aims of the present study were a. to investigate the long term effect of telmisartan (AT1R blocker) on tumor necrosis factor-α (TNF-α), interleukin 1-β (IL1-β) and nitric oxide (NO) release from glial cells. b. to examine the effect of intranasally administered telmisartan on amyloid burden and microglial activation in 5X familial AD (5XFAD) mice. Telmisartan effects in vivo were compared to those of perindopril (angiotensin converting enzyme inhibitor). Long-term-exposure of BV2 microglia to telmisartan significantly decreased lipopolysaccharide (LPS) -induced NO, inducible NO synthase, TNF-α and IL1-β synthesis. The effect of Telmisartan on NO production in BV2 cells was confirmed also in primary neonatal rat glial cells. Intranasal administration of telmisartan (1 mg/kg/day) for up to two months significantly reduced amyloid burden and CD11b expression (a marker for microglia) both in the cortex and hipoccampus of 5XFAD. Based on the current view of RAS and our data, showing reduced amyloid burden and glial activation in the brains of 5XFAD transgenic mice, one may envision potential intervention with the progression

  18. Acetylcholinesterase as a Biomarker in Environmental and Occupational Medicine: New Insights and Future Perspectives

    PubMed Central

    Caricato, Roberto; Calisi, Antonio; Giordano, Maria Elena; Schettino, Trifone

    2013-01-01

    Acetylcholinesterase (AChE) is a key enzyme in the nervous system. It terminates nerve impulses by catalysing the hydrolysis of neurotransmitter acetylcholine. As a specific molecular target of organophosphate and carbamate pesticides, acetylcholinesterase activity and its inhibition has been early recognized to be a human biological marker of pesticide poisoning. Measurement of AChE inhibition has been increasingly used in the last two decades as a biomarker of effect on nervous system following exposure to organophosphate and carbamate pesticides in occupational and environmental medicine. The success of this biomarker arises from the fact that it meets a number of characteristics necessary for the successful application of a biological response as biomarker in human biomonitoring: the response is easy to measure, it shows a dose-dependent behavior to pollutant exposure, it is sensitive, and it exhibits a link to health adverse effects. The aim of this work is to review and discuss the recent findings about acetylcholinesterase, including its sensitivity to other pollutants and the expression of different splice variants. These insights open new perspective for the future use of this biomarker in environmental and occupational human health monitoring. PMID:23936791

  19. Efforts toward treatments against aging of organophosphorus-inhibited acetylcholinesterase.

    PubMed

    Zhuang, Qinggeng; Young, Amneh; Callam, Christopher S; McElroy, Craig A; Ekici, Özlem Dogan; Yoder, Ryan J; Hadad, Christopher M

    2016-06-01

    Aging is a dealkylation reaction of organophosphorus (OP)-inhibited acetylcholinesterase (AChE). Despite many studies to date, aged AChE cannot be reactivated directly by traditional pyridinium oximes. This review summarizes strategies that are potentially valuable in the treatment against aging in OP poisoning. Among them, retardation of aging seeks to lower the rate of aging through the use of AChE effectors. These drugs should be administered before AChE is completely aged. For postaging treatment, realkylation of aged AChE by appropriate alkylators may pave the way for oxime treatment by neutralizing the oxyanion at the active site of aged AChE. The other two strategies, upregulation of AChE expression and introduction of exogenous AChE, cannot resurrect aged AChE but may compensate for lowered active AChE levels by in situ production or external introduction of active AChE. Upregulation of AChE expression can be triggered by some peptides. Sources of exogenous AChE can be whole blood or purified AChE, either from human or nonhuman species. PMID:27327269

  20. Perspectives for the structure-based design of acetylcholinesterase reactivators.

    PubMed

    Ochoa, Rodrigo; Rodriguez, Carlos A; Zuluaga, Andres F

    2016-07-01

    Rational design of active molecules through structure-based methods has been gaining adepts during the last decades due to the wider availability of protein structures, most of them conjugated with relevant ligands. Acetylcholinesterase (AChE) is a molecular target with a considerable amount of data related to its sequence and 3-dimensional structure. In addition, there are structural insights about the mechanism of action of the natural substrate and drugs used in Alzheimer's disease, organophosphorus compounds, among others. We looked for AChE structural data useful for in silico design of potential interacting molecules. In particular, we focused on information regarding the design of ligands aimed to reactivate AChE catalytic activity. The structures of 178 AChE were annotated and categorized on different subsets according to the nature of the ligand, source organisms and experimental details. We compared sequence homology among the active site from Torpedo californica, Mus musculus and Homo sapiens with the latter two species having the closest relationship (88.9% identity). In addition, the mechanism of organophosphorus binding and the design of effective reactivators are reviewed. A curated data collection obtained with information from several sources was included for researchers working on the field. Finally, a molecular dynamics simulation with human AChE indicated that the catalytic pocket volume stabilizes around 600 Å(3), providing additional clues for drug design. PMID:27450771

  1. Unified active and reactive power modulation of HVDC transmission systems

    NASA Astrophysics Data System (ADS)

    Grund, C. E.; Pohl, R. V.

    1981-11-01

    The power modulation of a high voltage direct current (HVDC) system for stabilization of an ac/dc network was investigated. It was found that simultaneous modulation of both dc current and voltage was more effective than just current modulation by itself, since the dc voltage modulation could be used to minimize the reactive power changes resulting from a change of the dc current. This helps stabilize the ac busbar voltages at the converters, which reduces undesirable load flow changes to voltage dependent ac loads, thus improving the effectiveness of the dc power modulation. This unified modulation control concept was evaluated by means of digital computer studies as well as a special purpose HVDC simulator. Several combined ac/dc power transmission systems were synthesized for testing of different modulation controller concepts. An optimum controller design incorporating a linear quadratic control algorithm with full state feedback was first studied. This provided a basis for comparison of suboptimal controller designs utilizing reduced state feedback and a Kalman filter state reconstruction technique.

  2. Organophosphorus Inhibition and Characterization of Recombinant Guinea Pig Acetylcholinesterase.

    PubMed

    Ruark, Christopher D; Chapleau, Richard R; Mahle, Deirdre A; Gearhart, Jeffery M

    2015-01-01

    Organophosphorus (OP) pesticides and nerve agents have been designed to inhibit the hydrolysis of the neurotransmitter acetylcholine by covalently binding to the active site serine of acetylcholinesterase while Alzheimer drugs and prophylactics, such as tacrine, are characterized by reversible binding. Historically, the guinea pig has been believed to be the best non-primate model for OP toxicology and medical countermeasure development because, similarly to humans, guinea pigs have low amounts of circulating OP metabolizing carboxylesterase. To explore the hypothesis that guinea pigs are the appropriate responder species for OP toxicology and medical countermeasure development, guinea pig acetylcholinesterase (gpAChE) was cloned into pENTR/D-TOPO, recombined into pT-Rex-DEST30 and expressed in Human Embryonic Kidney 293 cells. Recombinant gpAChE was purified to a specific activity of 800 U/mg using size exclusion and immobilized nickel affinity chromatography, with purity confirmed by gel electrophoresis. Ellman's assay was used to enzymatically characterize gpAChE, identifying a K(M) of 154±18.7 µmol L(-1) and a k(cat) of 4.79x10(4)±5.26x10(2) /sec. Apparent gpAChE IC50's for diisopropylfluorophosphate, dicrotophos, paraoxon, and an Alzheimer's drug, tacrine, were found to be 10.1±1.98, 337±108, 1.02±0.29 and 0.30±0.01 µmol L(-1), respectively. Apparent gpAChE inhibition constants for diisopropylfluorophosphate, dicrotophos, paraoxon, and tacrine were found to be 8.40±0.60, 4.50±0.30, 0.29±0.01 and 0.42±0.07 µmol L(-1), respectively. Lineweaver-Burk plots confirmed tacrine as a mixed inhibitor and paraoxon, dicrotophos and diisopropylfluorophosphate as irreversible non-competitive inhibitors. gpAChE bimolecular rate constants for diisopropylfluorophosphate, dicrotophos and paraoxon were found to be 1.44±0.33x10(4), 1.56±0.12x10(3) and 4.57± 0.23x10(5) L µmol(-1) min(-1), respectively. Although the blood levels of OP metabolizing carboxylesterases

  3. Pathways of ligand clearance in acetylcholinesterase by multiple copy sampling.

    PubMed

    Van Belle, D; De Maria, L; Iurcu, G; Wodak, S J

    2000-05-12

    The clearance of seven different ligands from the deeply buried active-site of Torpedo californica acetylcholinesterase is investigated by combining multiple copy sampling molecular dynamics simulations, with the analysis of protein-ligand interactions, protein motion and the electrostatic potential sampled by the ligand copies along their journey outwards. The considered ligands are the cations ammonium, methylammonium, and tetramethylammonium, the hydrophobic methane and neopentane, and the anionic product acetate and its neutral form, acetic acid. We find that the pathways explored by the different ligands vary with ligand size and chemical properties. Very small ligands, such as ammonium and methane, exit through several routes. One involves the main exit through the mouth of the enzyme gorge, another is through the so-called back door near Trp84, and a third uses a side door at a direction of approximately 45 degrees to the main exit. The larger polar ligands, methylammonium and acetic acid, leave through the main exit, but the bulkiest, tetramethylammonium and neopentane, as well as the smaller acetate ion, remain trapped in the enzyme gorge during the time of the simulations. The pattern of protein-ligand contacts during the diffusion process is highly non-random and differs for different ligands. A majority is made with aromatic side-chains, but classical H-bonds are also formed. In the case of acetate, but not acetic acid, the anionic and neutral form, respectively, of one of the reaction products, specific electrostatic interactions with protein groups, seem to slow ligand motion and interfere with protein flexibility; protonation of the acetate ion is therefore suggested to facilitate clearance. The Poisson-Boltzmann formalism is used to compute the electrostatic potential of the thermally fluctuating acetylcholinesterase protein at positions actually visited by the diffusing ligand copies. Ligands of different charge and size are shown to sample

  4. Crystal Structure of Snake Venom Acetylcholinesterase in Complex with Inhibitory Antibody Fragment Fab410 Bound at the Peripheral Site

    PubMed Central

    Bourne, Yves; Renault, Ludovic; Marchot, Pascale

    2015-01-01

    The acetylcholinesterase found in the venom of Bungarus fasciatus (BfAChE) is produced as a soluble, non-amphiphilic monomer with a canonical catalytic domain but a distinct C terminus compared with the other vertebrate enzymes. Moreover, the peripheral anionic site of BfAChE, a surface site located at the active site gorge entrance, bears two substitutions altering sensitivity to cationic inhibitors. Antibody Elec410, generated against Electrophorus electricus acetylcholinesterase (EeAChE), inhibits EeAChE and BfAChE by binding to their peripheral sites. However, both complexes retain significant residual catalytic activity, suggesting incomplete gorge occlusion by bound antibody and/or high frequency back door opening. To explore a novel acetylcholinesterase species, ascertain the molecular bases of inhibition by Elec410, and document the determinants and mechanisms for back door opening, we solved a 2.7-Å resolution crystal structure of natural BfAChE in complex with antibody fragment Fab410. Crystalline BfAChE forms the canonical dimer found in all acetylcholinesterase structures. Equally represented open and closed states of a back door channel, associated with alternate positions of a tyrosine phenol ring at the active site base, coexist in each subunit. At the BfAChE molecular surface, Fab410 is seated on the long Ω-loop between two N-glycan chains and partially occludes the gorge entrance, a position that fully reflects the available mutagenesis and biochemical data. Experimentally based flexible molecular docking supports a similar Fab410 binding mode onto the EeAChE antigen. These data document the molecular and dynamic peculiarities of BfAChE with high frequency back door opening, and the mode of action of Elec410 as one of the largest peptidic inhibitors targeting the acetylcholinesterase peripheral site. PMID:25411244

  5. Are soluble and membrane-bound rat brain acetylcholinesterase different

    SciTech Connect

    Andres, C.; el Mourabit, M.; Stutz, C.; Mark, J.; Waksman, A. )

    1990-11-01

    Salt-soluble and detergent-soluble acetylcholinesterases (AChE) from adult rat brain were purified to homogeneity and studied with the aim to establish the differences existing between these two forms. It was found that the enzymatic activities of the purified salt-soluble AChE as well as the detergent-soluble AChE were dependent on the Triton X-100 concentration. Moreover, the interaction of salt-soluble AChE with liposomes suggests amphiphilic behaviour of this enzyme. Serum cholinesterase (ChE) did not bind to liposomes but its activity was also detergent-dependent. Detergent-soluble AChE remained in solution below critical micellar concentrations of Triton X-100. SDS polyacrylamide gel electrophoresis of purified, Biobeads-treated and iodinated detergent-soluble 11 S AChE showed, under non reducing conditions, bands of 69 kD, 130 kD and greater than 250 kD corresponding, respectively, to monomers, dimers and probably tetramers of the same polypeptide chain. Under reducing conditions, only a 69 kD band was detected. It is proposed that an amphiphilic environment stabilizes the salt-soluble forms of AChE in the brain in vivo and that detergent-soluble Biobeads-treated 11 S AChE possess hydrophobic domain(s) different from the 20 kD peptide already described.

  6. Acetylcholinesterase in the human erythron. III. Regulation of differentiation.

    PubMed

    Barr, R D; Koekebakker, M

    1990-08-01

    Acetylcholinesterase (AChE) is present in both primitive and mature erythroid cells, but a role for the enzyme in human hematopoiesis has not been defined. This prospect represented the primary objective of the following study. In clonal culture of normal human bone marrow cells, a "wave" of AChE activity was demonstrated, rising from undetectable levels to a peak (of 1.48 femto-moles per min per cell) at 10 days in the course of progressive erythroid clonogenesis. At concentrations of enzyme inhibitor that clearly reduced AChE activity in a dose-dependent fashion, there was no overall effect on erythropoiesis in vitro, but the clones were generally smaller and significantly more often multi-focal than in control cultures. Furthermore, in the presence of AChE inhibitors, a concentration-dependent increase in the myeloid-erythroid ratios of the culture harvests was observed. Likewise, a clear reduction in hemoglobination was revealed, in cells of 10 day cultures, from a mean hemoglobin concentration of 35.0 pg per cell in controls to 20.1 pg per cell in the presence of the maximal concentration of the inhibitor (10(-6) M eserine). These data point to a role for AChE in the regulation of differentiation in the human erythron. PMID:2368693

  7. N-Acetylcholinesterase-Induced Apoptosis in Alzheimer's Disease

    PubMed Central

    Toiber, Debra; Berson, Amit; Greenberg, David; Melamed-Book, Naomi; Diamant, Sophia; Soreq, Hermona

    2008-01-01

    Background Alzheimer's disease (AD) involves loss of cholinergic neurons and Tau protein hyper-phosphorylation. Here, we report that overexpression of an N-terminally extended “synaptic” acetylcholinesterase variant, N-AChE-S is causally involved in both these phenomena. Methodology and Principal Findings In transfected primary brain cultures, N-AChE-S induced cell death, morphological impairments and caspase 3 activation. Rapid internalization of fluorescently labeled fasciculin-2 to N-AChE-S transfected cells indicated membranal localization. In cultured cell lines, N-AChE-S transfection activated the Tau kinase GSK3, induced Tau hyper-phosphorylation and caused apoptosis. N-AChE-S-induced cell death was suppressible by inhibiting GSK3 or caspases, by enforced overexpression of the anti-apoptotic Bcl2 proteins, or by AChE inhibition or silencing. Moreover, inherent N-AChE-S was upregulated by stressors inducing protein misfolding and calcium imbalances, both characteristic of AD; and in cortical tissues from AD patients, N-AChE-S overexpression coincides with Tau hyper-phosphorylation. Conclusions Together, these findings attribute an apoptogenic role to N-AChE-S and outline a potential value to AChE inhibitor therapeutics in early AD. PMID:18769671

  8. Toxin-Antitoxin Modules Are Pliable Switches Activated by Multiple Protease Pathways

    PubMed Central

    Muthuramalingam, Meenakumari; White, John C.; Bourne, Christina R.

    2016-01-01

    Toxin-antitoxin (TA) modules are bacterial regulatory switches that facilitate conflicting outcomes for cells by promoting a pro-survival phenotypic adaptation and/or by directly mediating cell death, all through the toxin activity upon degradation of antitoxin. Intensive study has revealed specific details of TA module functions, but significant gaps remain about the molecular details of activation via antitoxin degradation used by different bacteria and in different environments. This review summarizes the current state of knowledge about the interaction of antitoxins with cellular proteases Lon and ClpP to mediate TA module activation. An understanding of these processes can answer long-standing questions regarding stochastic versus specific activation of TA modules and provide insight into the potential for manipulation of TA modules to alter bacterial growth. PMID:27409636

  9. Modulation of Leishmania major aquaglyceroporin activity by a mitogen-activated protein kinase

    PubMed Central

    Mandal, Goutam; Sharma, Mansi; Kruse, Martin; Sander-Juelch, Claudia; Munro, Laura Anne; Wang, Yong; Vilg, Jenny Veide; Tamás, Markus J; Bhattacharjee, Hiranmoy; Wiese, Martin; Mukhopadhyay, Rita

    2012-01-01

    Summary Leishmania major aquaglyceroporin (LmjAQP1) adventitiously facilitates the uptake of antimonite [Sb(III)], an active form of Pentostam® or Glucantime®, which are the first line of defense against all forms of leishmaniasis. The present paper shows that LmjAQP1 activity is modulated by the mitogen-activated protein kinase, LmjMPK2. Leishmania parasites co-expressing LmjAQP1 and LmjMPK2 show increased Sb(III) uptake and increased Sb(III) sensitivity. When subjected to a hypo-osmotic stress, these cells show faster volume recovery than cells expressing LmjAQP1 alone. LmjAQP1 is phosphorylated in vivo at Thr197 and this phosphorylation requires LmjMPK2 activity. Lys42 of LmjMPK2 is critical for its kinase activity. Cells expressing altered T197A LmjAQP1 or K42A LmjMPK2 showed decreased Sb(III) influx and a slower volume recovery than cells expressing wild type proteins. Phosphorylation of LmjAQP1 led to a decrease in its turnover rate affecting LmjAQP1 activity. Although LmjAQP1 is localized to the flagellum of promastigotes, upon phosphorylation, it is relocalized to the entire surface of the parasite. L. mexicana promastigotes with an MPK2 deletion showed reduced Sb(III) uptake and slower volume recovery than wild type cells. This is the first report where a parasite aquaglyceroporin activity is post-translationally modulated by a MAP kinase. PMID:22779703

  10. Blackout!: An Event-Based Science Module. Teacher's Guide. Electricity and Solar Activity Module.

    ERIC Educational Resources Information Center

    Wright, Russell G.

    This book is designed for middle school earth science or physical science teachers to help their students learn scientific literacy through event-based science. Unlike traditional curricula, the event- based earth science module is a student-centered, interdisciplinary, inquiry-oriented program that emphasizes cooperative learning, teamwork,…

  11. Differential binding of bispyridinium oxime drugs with acetylcholinesterase

    PubMed Central

    Kesharwani, Manoj K; Ganguly, Bishwajit; Das, Amit; Bandyopadhyay, Tusar

    2010-01-01

    Aim: To performe a time-dependent topographical delineation of protein-drug interactions to gain molecular insight into the supremacy of Ortho-7 over HI-6 in reactivating tabun-conjugated mouse acetylcholinesterase (mAChE). Methods: We conducted all-atom steered molecular dynamics simulations of the two protein-drug complexes. Through a host of protein-drug interaction parameters (rupture force profiles, hydrogen bonds, water bridges, hydrophobic interactions), geometrical, and orientation ordering of the drugs, we monitored the enzyme's response during the release of the drugs from its active-site. Results: The results show the preferential binding of the drugs with the enzyme. The pyridinium ring of HI-6 shows excellent complementary binding with the peripheral anionic site, whereas one of two identical pyridinium rings of Ortho-7 has excellent binding compatibility in the enzyme active-site where it can orchestrate the reactivation process. We found that the active pyridinium ring of HI-6 undergoes a complete turn along the active site axis, directed away from the active-site region during the course of the simulation. Conclusion: Due to excellent cooperative binding of Ortho-7, as rendered by several cation-π interactions with the active-site gorge of the enzyme, Ortho-7 may be a more efficient reactivator than HI-6. Our work supports the growing body of evidence that the efficacy of the drugs is due to the differential bindings of the oximes with AChE and can aid to the rational design of oxime drugs. PMID:20140002

  12. PV Cell and Module Calibration Activities at NREL

    SciTech Connect

    Emery, K.; Anderberg, A.; Kiehl, J.; Mack, C.; Moriarty, T.; Ottoson, L.; Rummel, S.

    2005-11-01

    The performance of PV cells and modules with respect to standard reference conditions is a key indicator of progress of a given technology. This task provides the U.S. terrestrial PV community with the most accurate measurements that are technically possible in a timely fashion. The international module certification and accreditation program PVGap requires certification laboratories to maintain their calibration traceability path to groups like this one. The politics of a "world record" efficiency requires that an independent laboratory perform these measurements for credibility. Most manufacturers base their module peak watt rating upon standards and reference cells calibrated under this task. This task has been involved in reconciling disputes between manufacturers and their cell suppliers in terms of expected versus actual performance. This task has also served as a resource to the PV community for consultation on solar simulation, current versus voltage measurement instrumentation, measurement procedures and measurement artifacts.

  13. Activity of catalytic silver nanoparticles modulated by capping agent hydrophobicity.

    PubMed

    Janani, Seralathan; Stevenson, Priscilla; Veerappan, Anbazhagan

    2014-05-01

    In this paper, a facile in situ method is reported for the preparation of catalytic silver nanoparticles (AgNPs) using N-acyl tyramine (NATA) with variable hydrophobic acyl length. Scanning electron microscopic analysis shows that NATA exists initially as larger aggregates in alkaline aqueous solution. The addition of AgNO3 dissociates these larger aggregate and subsequently promotes the formation of self-assembled NATA and AgNPs. Characterization of AgNPs using UV-vis spectroscopy, scanning electron microscope and transmission electron microscope revealed that the hydrophobic acyl chain length of NATA does not influence the particle size, shape and morphology. All NATA-AgNPs yielded relatively identical values in full width at half-maximum (FWHM) analysis, indicating that the AgNPs prepared with NATA are relatively polydispersed at all tested acyl chain lengths. These nanoparticles are able to efficiently catalyze the reduction of 4-nitro phenol to 4-amino phenol, 2-nitro aniline to 1,2-diamino benzene, 2,4,6-trinitro phenol to 2,4,6-triamino phenol by NaBH4 in an aqueous environment. The reduction reaction rate is determined to be pseudo-first order and the apparent rate constant is linearly dependent on the hydrophobic acyl chain length of the NATA. All reaction kinetics presented an induction period, which is dependent on the N-acyl chain length, indicating that the hydrophobic effects play a critical role in bringing the substrate to the metal nanoparticle surface to induce the catalytic reaction. In this study, however, the five catalytic systems have similar size and polydispersity, differing only in terms of capping agent hydrophobicity, and shows different catalytic activity with respect to the alkyl chain length of the capping agent. As discussed, the ability to modulate the metal nanoparticles catalytic property, by modifying the capping agent hydrophobicity represents a promising future for developing an efficient nanocatalyst without altering the size

  14. Acetylcholinesterase inhibitory dimeric indole derivatives from the marine actinomycetes Rubrobacter radiotolerans.

    PubMed

    Li, Jian Lin; Huang, Lei; Liu, Juan; Song, Yan; Gao, Jie; Jung, Jee H; Liu, Yonghong; Chen, Guangtong

    2015-04-01

    Investigation of the bioactive secondary metabolites of the marine actinomycetes Rubrobacter radiotolerans led to the isolation and characterization of two naturally rare dimeric indole derivatives (1 and 2). The structures of these new compounds were elucidated by spectroscopic data interpretation, and the absolute configurations were assigned by CD calculations. The acetylcholinesterase (AchE) inhibitory activity of compounds 1 and 2 was evaluated, both of which showed moderate activity with IC50 values of 11.8 and 13.5μM, respectively. PMID:25655350

  15. Dihydroagarofuranoid Sesquiterpenes as Acetylcholinesterase Inhibitors from Celastraceae Plants: Maytenus disticha and Euonymus japonicus.

    PubMed

    Alarcón, Julio; Cespedes, Carlos L; Muñoz, Evelyn; Balbontin, Cristian; Valdes, Francisco; Gutierrez, Margarita; Astudillo, Luis; Seigler, David S

    2015-12-01

    Natural cholinesterase inhibitors have been found in many biological sources. Nine compounds with agarofuran (epoxyeudesmane) skeletons were isolated from seeds and aerial parts of Maytenus disticha and Euonymus japonicus. The identification and structural elucidation of compounds were based on spectroscopic data analyses. All compounds had inhibitory acetylcholinesterase (AChE) activity. These natural compounds, which possessed mixed or uncompetitive mechanisms of inhibitory activity against AChE, may be considered as models for the design and development of new naturally occurring drugs for management strategies for neurodegenerative diseases. This is the first report of these chemical structures for seeds of M. disticha. PMID:26545100

  16. A novel role for synaptic acetylcholinesterase as an apoptotic deoxyribonuclease

    PubMed Central

    Du, Aiying; Xie, Jing; Guo, Kaijie; Yang, Lei; Wan, Yihan; OuYang, Qi; Zhang, Xuejin; Niu, Xin; Lu, Lu; Wu, Jun; Zhang, Xuejun

    2015-01-01

    In addition to terminating neurotransmission by hydrolyzing acetylcholine, synaptic acetylcholinesterase (AChES) has been found to have a pro-apoptotic role. However, the underlying mechanism has rarely been investigated. Here, we report a nuclear translocation-dependent role for AChES as an apoptotic deoxyribonuclease (DNase). AChES polypeptide binds to and cleaves naked DNA at physiological pH in a Ca2+–Mg2+-dependent manner. It also cleaves chromosomal DNA both in pre-fixed and in apoptotic cells. In the presence of a pan-caspase inhibitor, the cleavage still occurred after nuclear translocation of AChES, implying that AChES-DNase acts in a CAD- and EndoG-independent manner. AChE gene knockout impairs apoptotic DNA cleavage; this impairment is rescued by overexpression of the wild-type but not (aa 32–138)-deleted AChES. Furthermore, in comparison with the nuclear-localized wild-type AChES, (aa 32–138)-deleted AChES loses the capacity to initiate apoptosis. These observations confirm that AChES mediates apoptosis via its DNase activity. PMID:27462404

  17. An Acetylcholinesterase-Deficient Mutant of the Nematode CAENORHABDITIS ELEGANS

    PubMed Central

    Johnson, Carl D.; Duckett, John G.; Culotti, Joseph G.; Herman, Robert K.; Meneely, Philip M.; Russell, Richard L.

    1981-01-01

    Within a set of five separable molecular forms of acetylcholinesterase found in the nematode Caenorhabditis elegans, previously reported differences in kinetic properties identify two classes, A and B, likely to be under separate genetic control. Using differences between these classes in sensitivity to inactivation by sodium deoxycholate, a screening procedure was devised to search for mutants affected only in class A forms. Among 171 previously isolated behavioral and morphological mutant strains examined by this procedure, one (PR946) proved to be of the expected type, exhibiting a selective deficiency of class A acetylcholinesterase forms. Although originally isolated because of its uncoordinated behavior, this strain was subsequently shown to harbor mutations in two genes; one in the previously identified gene unc-3, accounting for its behavior, and one in a newly identified gene, ace-1, accounting for its selective acetylcholinesterase deficiency. Derivatives homozygous only for the ace-1 mutation also lacked class A acetylcholinesterase forms, but were behaviorally and developmentally indistinguishable from wild type. The gene ace-1 has been mapped near the right end of the X chromosome. Gene dosage experiments suggest that it may be a structural gene for a component of class A acetylcholinesterase forms. PMID:7274654

  18. Active cancellation of residual amplitude modulation in a frequency-modulation based Fabry-Perot interferometer.

    PubMed

    Yu, Yinan; Wang, Yicheng; Pratt, Jon R

    2016-03-01

    Residual amplitude modulation (RAM) is one of the most common noise sources known to degrade the sensitivity of frequency modulation spectroscopy. RAM can arise as a result of the temperature dependent birefringence of the modulator crystal, which causes the orientation of the crystal's optical axis to shift with respect to the polarization of the incident light with temperature. In the fiber-based optical interferometer used on the National Institute of Standards and Technology calculable capacitor, RAM degrades the measured laser frequency stability and correlates with the environmental temperature fluctuations. We have demonstrated a simple approach that cancels out excessive RAM due to polarization mismatch between the light and the optical axis of the crystal. The approach allows us to measure the frequency noise of a heterodyne beat between two lasers individually locked to different resonant modes of a cavity with an accuracy better than 0.5 ppm, which meets the requirement to further determine the longitudinal mode number of the cavity length. Also, this approach has substantially mitigated the temperature dependency of the measurements of the cavity length and consequently the capacitance. PMID:27036752

  19. Active cancellation of residual amplitude modulation in a frequency-modulation based Fabry-Perot interferometer

    NASA Astrophysics Data System (ADS)

    Yu, Yinan; Wang, Yicheng; Pratt, Jon R.

    2016-03-01

    Residual amplitude modulation (RAM) is one of the most common noise sources known to degrade the sensitivity of frequency modulation spectroscopy. RAM can arise as a result of the temperature dependent birefringence of the modulator crystal, which causes the orientation of the crystal's optical axis to shift with respect to the polarization of the incident light with temperature. In the fiber-based optical interferometer used on the National Institute of Standards and Technology calculable capacitor, RAM degrades the measured laser frequency stability and correlates with the environmental temperature fluctuations. We have demonstrated a simple approach that cancels out excessive RAM due to polarization mismatch between the light and the optical axis of the crystal. The approach allows us to measure the frequency noise of a heterodyne beat between two lasers individually locked to different resonant modes of a cavity with an accuracy better than 0.5 ppm, which meets the requirement to further determine the longitudinal mode number of the cavity length. Also, this approach has substantially mitigated the temperature dependency of the measurements of the cavity length and consequently the capacitance.

  20. Energy-Storage Modules for Active Solar Heating and Cooling

    NASA Technical Reports Server (NTRS)

    Parker, J. C.

    1982-01-01

    34 page report describes a melting salt hydrate that stores 12 times as much heat as rocks and other heavy materials. Energy is stored mostly as latent heat; that is, heat that can be stored and recovered without any significant change in temperature. Report also describes development, evaluation and testing of permanently sealed modules containing salt hydrate mixture.

  1. Activity of a gelsolin-like actin modulator in rat skeletal muscle under protein catabolic conditions.

    PubMed Central

    D'Haese, J; Rutschmann, M; Dahlmann, B; Hinssen, H

    1987-01-01

    A gelsolin-like actin-modulating protein was isolated from rat skeletal muscle and characterized with respect to its interaction with actin. The protein, with a molecular mass of approx. 85 kDa, forms a stoichiometric complex with two actin molecules and is activated by micromolar concentrations of Ca2+. It effectively severs actin filaments and promotes nucleation of actin polymerization. The activity of this protein is detectable already in crude extracts by its capability to reduce the steady state viscosity of actin. Actin-modulating activities were determined in muscle extracts of rats kept under protein catabolic conditions, i.e. as generated by corticosterone treatment and starvation. In both cases we found a marked increase of modulator activity. The possibility is discussed that the increased activity of actin modulator indicates a fragmentation of actin filaments prior to the proteolytic degradation of actin. Images Fig. 2. PMID:3435453

  2. Membrane stretch and cytoplasmic Ca2+ independently modulate stretch-activated BK channel activity.

    PubMed

    Zhao, Hu-Cheng; Agula, Hasi; Zhang, Wei; Wang, Fa; Sokabe, Masahiro; Li, Lu-Ming

    2010-11-16

    Large conductance Ca(2+)-activated K(+) (BK) channels are responsible for changes in chemical and physical signals such as Ca(2+), Mg(2+) and membrane potentials. Previously, we reported that a BK channel cloned from chick heart (SAKCaC) is activated by membrane stretch. Molecular cloning and subsequent functional characterization of SAKCaC have shown that both the membrane stretch and intracellular Ca(2+) signal allosterically regulate the channel activity via the linker of the gating ring complex. Here we investigate how these two gating principles interact with each other. We found that stretch force activated SAKCaC in the absence of cytoplasmic Ca(2+). Lack of Ca(2+) bowl (a calcium binding motif) in SAKCaC diminished the Ca(2+)-dependent activation, but the mechanosensitivity of channel was intact. We also found that the abrogation of STREX (a proposed mechanosensing apparatus) in SAKCaC abolished the mechanosensitivity without altering the Ca(2+) sensitivity of channels. These observations indicate that membrane stretch and intracellular Ca(2+) could independently modulate SAKCaC activity. PMID:20673577

  3. Modulation of pulmonary macrophage superoxide release and tumoricidal activity following activation by biological response modifiers.

    PubMed

    Drath, D B

    1986-10-01

    Following immunologic activation, pulmonary macrophages may prevent or cause regression of lung metastases by mechanisms which remain largely unknown. The studies described here were designed to determine if enhanced oxygen metabolite release was related to postactivation tumoricidal activity. We have shown that in vitro activation of Fischer 344 rat pulmonary macrophages by either free or liposome-encapsulated muramyl dipeptide leads to both enhanced release of superoxide anions and marked tumoricidal activity against syngenic (Fischer 13762), allogeneic (Schmidt-Ruppin RR 1022) and xenogeneic (Fibrosarcoma MCA-F) 125I-deoxyuridine-labeled target cells. This immune modulator did not, however, metabolically activate pulmonary macrophages as effectively as liposome-encapsulated lipopolysaccharide. A 24-h in vitro incubation with either 150 U or 300 U of interferon-gamma (3 X 10(6) U/mg) or 30 U, 150 U or 300 U of interferon-alpha (6 X 10(5) U/mg) caused a significant elevation in superoxide release above controls, whereas short-term exposure (2 or 4 h) had little or no effect. Free or encapsulated 6-O-stearoyl muramyl dipeptide, on the other hand, did increase superoxide levels at all 3 time periods. When either interferon-gamma or free or encapsulated muramyl dipeptide derivative were administered to intact rats by either i.v. injection, intratracheal instillation or osmotic minipump infusion, pulmonary macrophage tumoricidal activity was observed 96 h after cell harvesting. Zymosan-stimulated superoxide release, however, was not consistently elevated above control or empty liposome treatment following this course of in vivo activation. The data collectively suggest that in vivo pulmonary macrophage activation to a tumoricidal state and metabolic activation resulting in enhanced superoxide may be separable events. PMID:3021650

  4. Russian Activities in Space Photovoltaic Power Modules with Concentrators

    NASA Technical Reports Server (NTRS)

    Andreev, Vyacheslav M.; Rumyantsev, Valeri D.

    2004-01-01

    Space concentrator modules with point-and line-focus Fresnel lenses and with reflective parabolic troughs have been developed recently at Ioffe Physico-Technical Institute. PV receivers for these modules are based: on the single junction LPE and MOCVD AlGaAs/GaAs solar cells characterized by AM0 efficiencies of 23.5 - 24% at 20 - 50 suns and 24 - 24.75 at 50 - 200 suns; on the mechanically stacked tandem AlGaAs/GaAs-GaSb cells with efficiency of 27 - 28 at 20 - 100 suns. MOCVD AlGaAs/GaAs cells with internal Bragg reflector have shown a higher radiation resistance as compared to a traditional structure. Monolithic two-terminal tandems AlGaAs (top)-GaAs (bottom) for space application and GaSb (top) - InGaAsSb (bottom) for TRV application are under development as well.

  5. Same Modulation but Different Starting Points: Performance Modulates Age Differences in Inferior Frontal Cortex Activity during Word-Retrieval

    PubMed Central

    Meinzer, Marcus; Flaisch, Tobias; Seeds, Lauren; Harnish, Stacy; Antonenko, Daria; Witte, Veronica; Lindenberg, Robert; Crosson, Bruce

    2012-01-01

    The neural basis of word-retrieval deficits in normal aging has rarely been assessed and the few previous functional imaging studies found enhanced activity in right prefrontal areas in healthy older compared to younger adults. However, more pronounced right prefrontal recruitment has primarily been observed during challenging task conditions. Moreover, increased task difficulty may result in enhanced activity in the ventral inferior frontal gyrus (vIFG) bilaterally in younger participants as well. Thus, the question arises whether increased activity in older participants represents an age-related phenomenon or reflects task difficulty effects. In the present study, we manipulated task difficulty during overt semantic and phonemic word-generation and used functional magnetic resonance imaging to assess activity patterns in the vIFG in healthy younger and older adults (N = 16/group; mean age: 24 vs. 69 years). Both groups produced fewer correct responses during the more difficult task conditions. Overall, older participants produced fewer correct responses and showed more pronounced task-related activity in the right vIFG. However, increased activity during the more difficult conditions was found in both groups. Absolute degree of activity was correlated with performance across groups, tasks and difficulty levels. Activity modulation (difficult vs. easy conditions) was correlated with the respective drop in performance across groups and tasks. In conclusion, vIFG activity levels and modulation of activity were mediated by performance accuracy in a similar way in both groups. Group differences in the right vIFG activity were explained by performance accuracy which needs to be considered in future functional imaging studies of healthy and pathological aging. PMID:22438970

  6. Same modulation but different starting points: performance modulates age differences in inferior frontal cortex activity during word-retrieval.

    PubMed

    Meinzer, Marcus; Flaisch, Tobias; Seeds, Lauren; Harnish, Stacy; Antonenko, Daria; Witte, Veronica; Lindenberg, Robert; Crosson, Bruce

    2012-01-01

    The neural basis of word-retrieval deficits in normal aging has rarely been assessed and the few previous functional imaging studies found enhanced activity in right prefrontal areas in healthy older compared to younger adults. However, more pronounced right prefrontal recruitment has primarily been observed during challenging task conditions. Moreover, increased task difficulty may result in enhanced activity in the ventral inferior frontal gyrus (vIFG) bilaterally in younger participants as well. Thus, the question arises whether increased activity in older participants represents an age-related phenomenon or reflects task difficulty effects. In the present study, we manipulated task difficulty during overt semantic and phonemic word-generation and used functional magnetic resonance imaging to assess activity patterns in the vIFG in healthy younger and older adults (N = 16/group; mean age: 24 vs. 69 years). Both groups produced fewer correct responses during the more difficult task conditions. Overall, older participants produced fewer correct responses and showed more pronounced task-related activity in the right vIFG. However, increased activity during the more difficult conditions was found in both groups. Absolute degree of activity was correlated with performance across groups, tasks and difficulty levels. Activity modulation (difficult vs. easy conditions) was correlated with the respective drop in performance across groups and tasks. In conclusion, vIFG activity levels and modulation of activity were mediated by performance accuracy in a similar way in both groups. Group differences in the right vIFG activity were explained by performance accuracy which needs to be considered in future functional imaging studies of healthy and pathological aging. PMID:22438970

  7. Caffeine Inhibits Acetylcholinesterase, But Not Butyrylcholinesterase

    PubMed Central

    Pohanka, Miroslav; Dobes, Petr

    2013-01-01

    Caffeine is an alkaloid with a stimulant effect in the body. It can interfere in transmissions based on acetylcholine, epinephrine, norepinephrine, serotonin, dopamine and glutamate. Clinical studies indicate that it can be involved in the slowing of Alzheimer disease pathology and some other effects. The effects are not well understood. In the present work, we focused on the question whether caffeine can inhibit acetylcholinesterase (AChE) and/or, butyrylcholinesterase (BChE), the two enzymes participating in cholinergic neurotransmission. A standard Ellman test with human AChE and BChE was done for altering concentrations of caffeine. The test was supported by an in silico examination as well. Donepezil and tacrine were used as standards. In compliance with Dixon’s plot, caffeine was proved to be a non-competitive inhibitor of AChE and BChE. However, inhibition of BChE was quite weak, as the inhibition constant, Ki, was 13.9 ± 7.4 mol/L. Inhibition of AChE was more relevant, as Ki was found to be 175 ± 9 μmol/L. The predicted free energy of binding was −6.7 kcal/mol. The proposed binding orientation of caffeine can interact with Trp86, and it can be stabilize by Tyr337 in comparison to the smaller Ala328 in the case of human BChE; thus, it can explain the lower binding affinity of caffeine for BChE with reference to AChE. The biological relevance of the findings is discussed. PMID:23698772

  8. Thermal denaturation of Bungarus fasciatus acetylcholinesterase: Is aggregation a driving force in protein unfolding?

    PubMed

    Shin, I; Wachtel, E; Roth, E; Bon, C; Silman, I; Weiner, L

    2002-08-01

    A monomeric form of acetylcholinesterase from the venom of Bungarus fasciatus is converted to a partially unfolded molten globule species by thermal inactivation, and subsequently aggregates rapidly. To separate the kinetics of unfolding from those of aggregation, single molecules of the monomeric enzyme were encapsulated in reverse micelles of Brij 30 in 2,2,4-trimethylpentane, or in large unilamellar vesicles of egg lecithin/cholesterol at various protein/micelle (vesicle) ratios. The first-order rate constant for thermal inactivation at 45 degrees C, of single molecules entrapped within the reverse micelles (0.031 min(-1)), was higher than in aqueous solution (0.007 min(-1)) or in the presence of normal micelles (0.020 min(-1)). This clearly shows that aggregation does not provide the driving force for thermal inactivation of BfAChE. Within the large unilamellar vesicles, at average protein/vesicle ratios of 1:1 and 10:1, the first-order rate constants for thermal inactivation of the encapsulated monomeric acetylcholinesterase, at 53 degrees C, were 0.317 and 0.342 min(-1), respectively. A crosslinking technique, utilizing the photosensitive probe, hypericin, showed that thermal denaturation produces a distribution of species ranging from dimers through to large aggregates. Consequently, at a protein/vesicle ratio of 10:1, aggregation can occur upon thermal denaturation. Thus, these experiments also demonstrate that aggregation does not drive the thermal unfolding of Bungarus fasciatus acetylcholinesterase. Our experimental approach also permitted monitoring of recovery of enzymic activity after thermal denaturation in the absence of a competing aggregation process. Whereas no detectable recovery of enzymic activity could be observed in aqueous solution, up to 23% activity could be obtained for enzyme sequestered in the reverse micelles. PMID:12142456

  9. Probing the origins of human acetylcholinesterase inhibition via QSAR modeling and molecular docking.

    PubMed

    Simeon, Saw; Anuwongcharoen, Nuttapat; Shoombuatong, Watshara; Malik, Aijaz Ahmad; Prachayasittikul, Virapong; Wikberg, Jarl E S; Nantasenamat, Chanin

    2016-01-01

    Alzheimer's disease (AD) is a chronic neurodegenerative disease which leads to the gradual loss of neuronal cells. Several hypotheses for AD exists (e.g., cholinergic, amyloid, tau hypotheses, etc.). As per the cholinergic hypothesis, the deficiency of choline is responsible for AD; therefore, the inhibition of AChE is a lucrative therapeutic strategy for the treatment of AD. Acetylcholinesterase (AChE) is an enzyme that catalyzes the breakdown of the neurotransmitter acetylcholine that is essential for cognition and memory. A large non-redundant data set of 2,570 compounds with reported IC50 values against AChE was obtained from ChEMBL and employed in quantitative structure-activity relationship (QSAR) study so as to gain insights on their origin of bioactivity. AChE inhibitors were described by a set of 12 fingerprint descriptors and predictive models were constructed from 100 different data splits using random forest. Generated models afforded R (2), [Formula: see text] and [Formula: see text] values in ranges of 0.66-0.93, 0.55-0.79 and 0.56-0.81 for the training set, 10-fold cross-validated set and external set, respectively. The best model built using the substructure count was selected according to the OECD guidelines and it afforded R (2), [Formula: see text] and [Formula: see text] values of 0.92 ± 0.01, 0.78 ± 0.06 and 0.78 ± 0.05, respectively. Furthermore, Y-scrambling was applied to evaluate the possibility of chance correlation of the predictive model. Subsequently, a thorough analysis of the substructure fingerprint count was conducted to provide informative insights on the inhibitory activity of AChE inhibitors. Moreover, Kennard-Stone sampling of the actives were applied to select 30 diverse compounds for further molecular docking studies in order to gain structural insights on the origin of AChE inhibition. Site-moiety mapping of compounds from the diversity set revealed three binding anchors encompassing both hydrogen bonding and van der Waals

  10. Acetylcholinesterase in the human erythron. II. Biochemical assay.

    PubMed

    Barr, R D; Koekebakker, M; Lawson, A A

    1988-08-01

    Acetylcholinesterase (AChE) is an integral erythrocyte membrane protein. A role for the enzyme in the developing human erythron is being explored. Assays of AchE by the standard Ellman technique overestimate the amount of enzyme by failing to account for the contribution of hemoglobin to the optical density of the reaction mixture. Furthermore, reliance on substrate selection alone for specificity is unsatisfactory. Incorporation of inhibitors of "true" AchE and of pseudocholinesterase confer greater ability to distinguish one enzyme from the other. In our experience, the inhibitor constant (Kl) for edrophonium, which is highly specific for AChE, is approximately 5 x 10(-5) M against adult human erythrocytes that contain significantly more total cholinesterase activity than do erythrocytes from umbilical cord blood. This consists of both "true" and "pseudo" enzyme, the former predominating and accounting for 0.75-1.65 (mean 1.02, median 0.87) femtomoles of substrate hydrolysed per min per cell in adult blood, with values of 0.15-1.04 (mean 0.71, median 0.73) obtained on cord blood. Moreover, the enzyme activity in neonatal erythrocytes has a rather different inhibitor profile from that of adult cells. AChE was also demonstrated in fresh (ALL) and cultured (K562 and HL60) human leukemic cells, as well as in primitive granulocyte-macrophage and erythroid cells cloned from normal human bone marrow. In the erythroid colonies the enzyme activity was 0-3.76 (mean 1.20, median 0.76) femtomoles per min per cell, apparently the first successful measurement of AChE in such cells. PMID:3166338

  11. Finite Element Learning Modules as Active Learning Tools

    ERIC Educational Resources Information Center

    Brown, Ashland O.; Jensen, Daniel; Rencis, Joseph; Wood, Kristin; Wood, John; White, Christina; Raaberg, Kristen Kaufman; Coffman, Josh

    2012-01-01

    The purpose of active learning is to solicit participation by students beyond the passive mode of traditional classroom lectures. Reading, writing, participating in discussions, hands-on activities, engaging in active problem solving, and collaborative learning can all be involved. The skills acquired during active learning tend to go above and…

  12. Acetylcholinesterase: an enzymatic marker of human red blood cell aging.

    PubMed

    Prall, Y G; Gambhir, K K; Ampy, F R

    1998-01-01

    The purpose of this investigation was to determine whether acetylcholinesterase (AChE) can be used as a marker of cell aging in human red blood cells (RBCs). This study used consented subjects; both males and females in an age range of 21-42 years. The blood samples (8-9 mL) were drawn in tubes containing sodium heparin or EDTA as anticoagulants. To avoid contamination with other cells, (lymphocytes, monocytes and reticulocytes), RBCs were purified (PRBC) by Hypaque-Ficoll gradient technique. The PRBCs were subfractionated into young (y) (1.08-1.09), mid (m) (1.09-1.11) and old (o) (1.11-1.12) percoll density (g/mL) fractions using a discontinuous percoll gradient. The mean +/- 1 SD AChE per gram hemoglobin (U/g Hgb) activities in whole blood (WB) purified human red blood cells (PRBCs), young human red blood cells (y-RBCs), mid age human red blood cells (m-RBCs) and old human red blood cells (o-RBCs) were 27.4 +/- 2.98, 26.0 +/- 2.33, 25.5 +/- 1.64, 20.3 +/- 3.84, 14.6 +/- 3.42 in males and 26.3 +/- 4.44, 24.8 /- 4.83, 26.4 +/- 4.59, 24.0 +/- 5.50 and 12.4 +/- 7.09 in females respectively. Although there was variation in the data, the results indicated that old human red blood cells showed significantly (p<.05) lower AChE activity compared to young human red blood cells of both sexes. These preliminary but novel observations suggest that AChE can be an excellent enzymatic marker for RBC aging in man. PMID:9698047

  13. Variable Glutamine-Rich Repeats Modulate Transcription Factor Activity

    PubMed Central

    Gemayel, Rita; Chavali, Sreenivas; Pougach, Ksenia; Legendre, Matthieu; Zhu, Bo; Boeynaems, Steven; van der Zande, Elisa; Gevaert, Kris; Rousseau, Frederic; Schymkowitz, Joost; Babu, M. Madan; Verstrepen, Kevin J.

    2015-01-01

    Summary Excessive expansions of glutamine (Q)-rich repeats in various human proteins are known to result in severe neurodegenerative disorders such as Huntington’s disease and several ataxias. However, the physiological role of these repeats and the consequences of more moderate repeat variation remain unknown. Here, we demonstrate that Q-rich domains are highly enriched in eukaryotic transcription factors where they act as functional modulators. Incremental changes in the number of repeats in the yeast transcriptional regulator Ssn6 (Cyc8) result in systematic, repeat-length-dependent variation in expression of target genes that result in direct phenotypic changes. The function of Ssn6 increases with its repeat number until a certain threshold where further expansion leads to aggregation. Quantitative proteomic analysis reveals that the Ssn6 repeats affect its solubility and interactions with Tup1 and other regulators. Thus, Q-rich repeats are dynamic functional domains that modulate a regulator’s innate function, with the inherent risk of pathogenic repeat expansions. PMID:26257283

  14. Peroxisome proliferator-activated receptor β/δ induces myogenesis by modulating myostatin activity.

    PubMed

    Bonala, Sabeera; Lokireddy, Sudarsanareddy; Arigela, Harikumar; Teng, Serena; Wahli, Walter; Sharma, Mridula; McFarlane, Craig; Kambadur, Ravi

    2012-04-13

    Classically, peroxisome proliferator-activated receptor β/δ (PPARβ/δ) function was thought to be restricted to enhancing adipocyte differentiation and development of adipose-like cells from other lineages. However, recent studies have revealed a critical role for PPARβ/δ during skeletal muscle growth and regeneration. Although PPARβ/δ has been implicated in regulating myogenesis, little is presently known about the role and, for that matter, the mechanism(s) of action of PPARβ/δ in regulating postnatal myogenesis. Here we report for the first time, using a PPARβ/δ-specific ligand (L165041) and the PPARβ/δ-null mouse model, that PPARβ/δ enhances postnatal myogenesis through increasing both myoblast proliferation and differentiation. In addition, we have identified Gasp-1 (growth and differentiation factor-associated serum protein-1) as a novel downstream target of PPARβ/δ in skeletal muscle. In agreement, reduced Gasp-1 expression was detected in PPARβ/δ-null mice muscle tissue. We further report that a functional PPAR-responsive element within the 1.5-kb proximal Gasp-1 promoter region is critical for PPARβ/δ regulation of Gasp-1. Gasp-1 has been reported to bind to and inhibit the activity of myostatin; consistent with this, we found that enhanced secretion of Gasp-1, increased Gasp-1 myostatin interaction and significantly reduced myostatin activity upon L165041-mediated activation of PPARβ/δ. Moreover, we analyzed the ability of hGASP-1 to regulate myogenesis independently of PPARβ/δ activation. The results revealed that hGASP-1 protein treatment enhances myoblast proliferation and differentiation, whereas silencing of hGASP-1 results in defective myogenesis. Taken together these data revealed that PPARβ/δ is a positive regulator of skeletal muscle myogenesis, which functions through negatively modulating myostatin activity via a mechanism involving Gasp-1. PMID:22362769

  15. Pre-stimulus BOLD-network activation modulates EEG spectral activity during working memory retention.

    PubMed

    Kottlow, Mara; Schlaepfer, Anthony; Baenninger, Anja; Michels, Lars; Brandeis, Daniel; Koenig, Thomas

    2015-01-01

    Working memory (WM) processes depend on our momentary mental state and therefore exhibit considerable fluctuations. Here, we investigate the interplay of task-preparatory and task-related brain activity as represented by pre-stimulus BOLD-fluctuations and spectral EEG from the retention periods of a visual WM task. Visual WM is used to maintain sensory information in the brain enabling the performance of cognitive operations and is associated with mental health. We tested 22 subjects simultaneously with EEG and fMRI while performing a visuo-verbal Sternberg task with two different loads, allowing for the temporal separation of preparation, encoding, retention and retrieval periods. Four temporally coherent networks (TCNs)-the default mode network (DMN), the dorsal attention, the right and the left WM network-were extracted from the continuous BOLD data by means of a group ICA. Subsequently, the modulatory effect of these networks' pre-stimulus activation upon retention-related EEG activity in the theta, alpha, and beta frequencies was analyzed. The obtained results are informative in the context of state-dependent information processing. We were able to replicate two well-known load-dependent effects: the frontal-midline theta increase during the task and the decrease of pre-stimulus DMN activity. As our main finding, these two measures seem to depend on each other as the significant negative correlations at frontal-midline channels suggested. Thus, suppressed pre-stimulus DMN levels facilitated later task related frontal midline theta increases. In general, based on previous findings that neuronal coupling in different frequency bands may underlie distinct functions in WM retention, our results suggest that processes reflected by spectral oscillations during retention seem not only to be "online" synchronized with activity in different attention-related networks but are also modulated by activity in these networks during preparation intervals. PMID:25999828

  16. Pre-stimulus BOLD-network activation modulates EEG spectral activity during working memory retention

    PubMed Central

    Kottlow, Mara; Schlaepfer, Anthony; Baenninger, Anja; Michels, Lars; Brandeis, Daniel; Koenig, Thomas

    2015-01-01

    Working memory (WM) processes depend on our momentary mental state and therefore exhibit considerable fluctuations. Here, we investigate the interplay of task-preparatory and task-related brain activity as represented by pre-stimulus BOLD-fluctuations and spectral EEG from the retention periods of a visual WM task. Visual WM is used to maintain sensory information in the brain enabling the performance of cognitive operations and is associated with mental health. We tested 22 subjects simultaneously with EEG and fMRI while performing a visuo-verbal Sternberg task with two different loads, allowing for the temporal separation of preparation, encoding, retention and retrieval periods. Four temporally coherent networks (TCNs)—the default mode network (DMN), the dorsal attention, the right and the left WM network—were extracted from the continuous BOLD data by means of a group ICA. Subsequently, the modulatory effect of these networks' pre-stimulus activation upon retention-related EEG activity in the theta, alpha, and beta frequencies was analyzed. The obtained results are informative in the context of state-dependent information processing. We were able to replicate two well-known load-dependent effects: the frontal-midline theta increase during the task and the decrease of pre-stimulus DMN activity. As our main finding, these two measures seem to depend on each other as the significant negative correlations at frontal-midline channels suggested. Thus, suppressed pre-stimulus DMN levels facilitated later task related frontal midline theta increases. In general, based on previous findings that neuronal coupling in different frequency bands may underlie distinct functions in WM retention, our results suggest that processes reflected by spectral oscillations during retention seem not only to be “online” synchronized with activity in different attention-related networks but are also modulated by activity in these networks during preparation intervals. PMID

  17. An active lighting module with natural light guiding system and solid state source for indoor illumination

    NASA Astrophysics Data System (ADS)

    Chen, Chi-An; Chen, Yi-Yung; Whang, Allen Jong-Woei

    2009-08-01

    Recently, many researches focus on healthy lighting with sunlight. A Natural Light Guiding System includes collecting, transmitting, and lighting parts. In general, the lighting module of the Natural Light Guiding System only uses scattering element, such as diffuser, to achieve uniform illumination. With the passive lighting module, the application of the Natural Light Guiding System is limited because sunlight is dynamic source. When the sunlight is weak at morning, at evening, or on cloudy day, the illumination system is fail. In this paper, we provide an active lighting module that includes the lighting part of Natural Light Guiding System, LED auxiliary sources, optical elements, and optical detector. We use optical simulation tool to design and simulate the efficiency of the active module. The optical element can redistribute the sunlight only, LED light only, or sunlight with LED light to achieve uniform illumination. With the feedback of the detector, the active lighting module will adjust the intensity of LED to provide a steady illumination. Moreover, the module could replace the backlight module of LCD TV when the house has Natural Light Guiding System for saving energy and higher performance of image.

  18. Myelin-Derived Lipids Modulate Macrophage Activity by Liver X Receptor Activation

    PubMed Central

    Huynh-Thu, Vân Anh; Irrthum, Alexandre; Smeets, Hubert J. M.; Gustafsson, Jan-Åke; Steffensen, Knut R.; Mulder, Monique; Stinissen, Piet; Hellings, Niels; Hendriks, Jerome J. A.

    2012-01-01

    Multiple sclerosis is a chronic, inflammatory, demyelinating disease of the central nervous system in which macrophages and microglia play a central role. Foamy macrophages and microglia, containing degenerated myelin, are abundantly found in active multiple sclerosis lesions. Recent studies have described an altered macrophage phenotype after myelin internalization. However, it is unclear by which mechanisms myelin affects the phenotype of macrophages and how this phenotype can influence lesion progression. Here we demonstrate, by using genome wide gene expression analysis, that myelin-phagocytosing macrophages have an enhanced expression of genes involved in migration, phagocytosis and inflammation. Interestingly, myelin internalization also induced the expression of genes involved in liver-X-receptor signaling and cholesterol efflux. In vitro validation shows that myelin-phagocytosing macrophages indeed have an increased capacity to dispose intracellular cholesterol. In addition, myelin suppresses the secretion of the pro-inflammatory mediator IL-6 by macrophages, which was mediated by activation of liver-X-receptor β. Our data show that myelin modulates the phenotype of macrophages by nuclear receptor activation, which may subsequently affect lesion progression in demyelinating diseases such as multiple sclerosis. PMID:22984598

  19. Myelin-derived lipids modulate macrophage activity by liver X receptor activation.

    PubMed

    Bogie, Jeroen F J; Timmermans, Silke; Huynh-Thu, Vân Anh; Irrthum, Alexandre; Smeets, Hubert J M; Gustafsson, Jan-Åke; Steffensen, Knut R; Mulder, Monique; Stinissen, Piet; Hellings, Niels; Hendriks, Jerome J A

    2012-01-01

    Multiple sclerosis is a chronic, inflammatory, demyelinating disease of the central nervous system in which macrophages and microglia play a central role. Foamy macrophages and microglia, containing degenerated myelin, are abundantly found in active multiple sclerosis lesions. Recent studies have described an altered macrophage phenotype after myelin internalization. However, it is unclear by which mechanisms myelin affects the phenotype of macrophages and how this phenotype can influence lesion progression. Here we demonstrate, by using genome wide gene expression analysis, that myelin-phagocytosing macrophages have an enhanced expression of genes involved in migration, phagocytosis and inflammation. Interestingly, myelin internalization also induced the expression of genes involved in liver-X-receptor signaling and cholesterol efflux. In vitro validation shows that myelin-phagocytosing macrophages indeed have an increased capacity to dispose intracellular cholesterol. In addition, myelin suppresses the secretion of the pro-inflammatory mediator IL-6 by macrophages, which was mediated by activation of liver-X-receptor β. Our data show that myelin modulates the phenotype of macrophages by nuclear receptor activation, which may subsequently affect lesion progression in demyelinating diseases such as multiple sclerosis. PMID:22984598

  20. Inactivation studies of acetylcholinesterase with phenylmethylsulfonyl fluoride.

    PubMed

    Kraut, D; Goff, H; Pai, R K; Hosea, N A; Silman, I; Sussman, J L; Taylor, P; Voet, J G

    2000-06-01

    Acetylcholinesterase (AChE), a serine hydrolase, is potentially susceptible to inactivation by phenylmethylsulfonyl fluoride (PMSF) and benzenesulfonyl fluoride (BSF). Although BSF inhibits both mouse and Torpedo californica AChE, PMSF does not react measurably with the T. californica enzyme. To understand the residue changes responsible for the change in reactivity, we studied the inactivation of wild-type T. californica and mouse AChE and mutants of both by BSF and PMSF both in the presence and absence of substrate. The enzymes investigated were wild-type mouse AChE, wild-type T. californica AChE, wild-type mouse butyrylcholinesterase, mouse Y330F, Y330A, F288L, and F290I, and the double mutant T. californica F288L/F290V (all mutants given T. californica numbering). Inactivation rate constants for T. californica AChE confirmed previous reports that this enzyme is not inactivated by PMSF. Wild-type mouse AChE and mouse mutants Y330F and Y330A all had similar inactivation rate constants with PMSF, implying that the difference between mouse and T. californica AChE at position 330 is not responsible for their differing PMSF sensitivities. In addition, butyrylcholinesterase and mouse AChE mutants F288L and F290I had increased rate constants ( approximately 14 fold) over those of wild-type mouse AChE, indicating that these residues may be responsible for the increased sensitivity to inactivation by PMSF of butyrylcholinesterase. The double mutant T. californica AChE F288L/F290V had a rate constant nearly identical with the rate constant for the F288L and F290I mouse mutant AChEs, representing an increase of approximately 4000-fold over the T. californica wild-type enzyme. It remains unclear why these two positions have more importance for T. californica AChE than for mouse AChE. PMID:10825396

  1. Shuttle extravehicular activity signal processor pulse amplitude modulation decommutator

    NASA Technical Reports Server (NTRS)

    Noble, D. E.; Conrad, W. M.

    1974-01-01

    To provide data with long-term stability and accuracy, the pulse amplitude modulation (PAM) decommutator was synchronized to the PAM-return to zero wavetrain, and each channel was sampled with a common sample and hold circuit and digitized sequentially. The digital value of each channel was then scaled by the digital value of the calibration channels. The corrected digital value of each channel was stored for one complete frame and then transferred to the multiplexer-demultiplexer at a high rate in one block of serial digital data. A test model was built to demonstrate this design approach taken for the PAM decom and performance data was provided. The accuracies obtained with various signal to noise ratios are shown.

  2. NEUROTOXICITY OF PARATHION-INDUCED ACETYLCHOLINESTERASE INHIBITION IN NEONATAL RATS

    EPA Science Inventory

    The biochemical and morphological neurotoxic effects of postnatal acetylcholinesterase (AChE) inhibition were examined in rat pups dosed with parathion, at time points critical to hippocampal neurogenesis and synaptogenesis (i.e., D5-20). ippocampal cytopathology as assessed by l...

  3. Complexity of acetylcholinesterases in biting flies and ticks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Acetylcholinesterase (AChE) inhibitors function as pesticides for invertebrates, vertebrate nerve agents, and medicine to reduce cognitive effects of Alzheimer’s disease. Organophosphate (OP) pesticides have been widely used to control biting flies and ticks, however, OP-resistance has compromised c...

  4. Acetylcholinesterases of Blood-feeding Flies and Ticks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Acetylcholinesterase (AChE) is the biochemical target of organophosphate (OP) and carbamate pesticides for invertebrates, vertebrate nerve agents, and AChE inhibitors used to reduce effects of Alzheimer’s disease. Organophosphate pesticides (OPs) are widely used to control blood-feeding arthropods, ...

  5. Allobetulin derived seco-oleananedicarboxylates act as inhibitors of acetylcholinesterase.

    PubMed

    Heller, Lucie; Schwarz, Stefan; Obernauer, Anja; Csuk, René

    2015-07-01

    Ring opening of allobetulone gave either seco-acid 8 or di-acid 4. These acids were converted into esters that were screened by Ellman's assay. A dibutenylester of low cytotoxicity (NIH 3T3 murine embryonic fibroblasts) was shown to be a good mixed-type inhibitor (Ki=3.39, Ki'=2.26μM) for acetylcholinesterase. PMID:25980913

  6. Introducing Dynamic Combinatorial Chemistry: Probing the Substrate Selectivity of Acetylcholinesterase

    ERIC Educational Resources Information Center

    Angelin, Marcus; Larsson, Rikard; Vongvilai, Pornrapee; Ramstrom, Olof

    2010-01-01

    In this laboratory experiment, college students are introduced to dynamic combinatorial chemistry (DCC) and apply it to determine the substrate selectivity of acetylcholinesterase (AChE). Initially, the students construct a chemical library of dynamically interchanging thioesters and thiols. Then, AChE is added and allowed to select and hydrolyze…

  7. Staphylococcal Enterotoxin O Exhibits Cell Cycle Modulating Activity

    PubMed Central

    Hodille, Elisabeth; Alekseeva, Ludmila; Berkova, Nadia; Serrier, Asma; Badiou, Cedric; Gilquin, Benoit; Brun, Virginie; Vandenesch, François; Terman, David S.; Lina, Gerard

    2016-01-01

    Maintenance of an intact epithelial barrier constitutes a pivotal defense mechanism against infections. Staphylococcus aureus is a versatile pathogen that produces multiple factors including exotoxins that promote tissue alterations. The aim of the present study is to investigate the cytopathic effect of staphylococcal exotoxins SEA, SEG, SEI, SElM, SElN and SElO on the cell cycle of various human cell lines. Among all tested exotoxins only SEIO inhibited the proliferation of a broad panel of human tumor cell lines in vitro. Evaluation of a LDH release and a DNA fragmentation of host cells exposed to SEIO revealed that the toxin does not induce necrosis or apoptosis. Analysis of the DNA content of tumor cells synchronized by serum starvation after exposure to SEIO showed G0/G1 cell cycle delay. The cell cycle modulating feature of SEIO was confirmed by the flow cytometry analysis of synchronized cells exposed to supernatants of isogenic S. aureus strains wherein only supernatant of the SElO producing strain induced G0/G1 phase delay. The results of yeast-two-hybrid analysis indicated that SEIO’s potential partner is cullin-3, involved in the transition from G1 to S phase. In conclusion, we provide evidence that SEIO inhibits cell proliferation without inducing cell death, by delaying host cell entry into the G0/G1 phase of the cell cycle. We speculate that this unique cell cycle modulating feature allows SEIO producing bacteria to gain advantage by arresting the cell cycle of target cells as part of a broader invasive strategy. PMID:27148168

  8. Staphylococcal Enterotoxin O Exhibits Cell Cycle Modulating Activity.

    PubMed

    Hodille, Elisabeth; Alekseeva, Ludmila; Berkova, Nadia; Serrier, Asma; Badiou, Cedric; Gilquin, Benoit; Brun, Virginie; Vandenesch, François; Terman, David S; Lina, Gerard

    2016-01-01

    Maintenance of an intact epithelial barrier constitutes a pivotal defense mechanism against infections. Staphylococcus aureus is a versatile pathogen that produces multiple factors including exotoxins that promote tissue alterations. The aim of the present study is to investigate the cytopathic effect of staphylococcal exotoxins SEA, SEG, SEI, SElM, SElN and SElO on the cell cycle of various human cell lines. Among all tested exotoxins only SEIO inhibited the proliferation of a broad panel of human tumor cell lines in vitro. Evaluation of a LDH release and a DNA fragmentation of host cells exposed to SEIO revealed that the toxin does not induce necrosis or apoptosis. Analysis of the DNA content of tumor cells synchronized by serum starvation after exposure to SEIO showed G0/G1 cell cycle delay. The cell cycle modulating feature of SEIO was confirmed by the flow cytometry analysis of synchronized cells exposed to supernatants of isogenic S. aureus strains wherein only supernatant of the SElO producing strain induced G0/G1 phase delay. The results of yeast-two-hybrid analysis indicated that SEIO's potential partner is cullin-3, involved in the transition from G1 to S phase. In conclusion, we provide evidence that SEIO inhibits cell proliferation without inducing cell death, by delaying host cell entry into the G0/G1 phase of the cell cycle. We speculate that this unique cell cycle modulating feature allows SEIO producing bacteria to gain advantage by arresting the cell cycle of target cells as part of a broader invasive strategy. PMID:27148168

  9. Virtual Screening of Acetylcholinesterase Inhibitors Using the Lipinski's Rule of Five and ZINC Databank

    PubMed Central

    Nogara, Pablo Andrei; Saraiva, Rogério de Aquino; Caeran Bueno, Diones; Lissner, Lílian Juliana; Lenz Dalla Corte, Cristiane; Braga, Marcos M.; Rosemberg, Denis Broock; Rocha, João Batista Teixeira

    2015-01-01

    Alzheimer's disease (AD) is a progressive and neurodegenerative pathology that can affect people over 65 years of age. It causes several complications, such as behavioral changes, language deficits, depression, and memory impairments. One of the methods used to treat AD is the increase of acetylcholine (ACh) in the brain by using acetylcholinesterase inhibitors (AChEIs). In this study, we used the ZINC databank and the Lipinski's rule of five to perform a virtual screening and a molecular docking (using Auto Dock Vina 1.1.1) aiming to select possible compounds that have quaternary ammonium atom able to inhibit acetylcholinesterase (AChE) activity. The molecules were obtained by screening and further in vitro assays were performed to analyze the most potent inhibitors through the IC50 value and also to describe the interaction models between inhibitors and enzyme by molecular docking. The results showed that compound D inhibited AChE activity from different vertebrate sources and butyrylcholinesterase (BChE) from Equus ferus (EfBChE), with IC50 ranging from 1.69 ± 0.46 to 5.64 ± 2.47 µM. Compound D interacted with the peripheral anionic subsite in both enzymes, blocking substrate entrance to the active site. In contrast, compound C had higher specificity as inhibitor of EfBChE. In conclusion, the screening was effective in finding inhibitors of AChE and BuChE from different organisms. PMID:25685814

  10. Structural basis of femtomolar inhibitors for acetylcholinesterase subtype selectivity: insights from computational simulations.

    PubMed

    Zhu, Xiao-Lei; Yu, Ning-Xi; Hao, Ge-Fei; Yang, Wen-Chao; Yang, Guang-Fu

    2013-04-01

    Acetylcholinesterase (AChE) is a key enzyme of the cholinergic nervous system. More than one gene encodes the synaptic AChE target. As the most potent known AChE inhibitor, the syn1-TZ2PA6 isomer was recently shown to have higher affinity as a reversible organic inhibitor of acetylcholinesterase1 (AChE1) than the anti1-TZ2PA6 isomer. Opposite selectivity has been shown for acetylcholinesterase2 (AChE2). In an attempt to understand the selectivity of the syn1-TZ2PA6 and anti1-TZ2PA6 isomers for AChE1 and AChE2, six molecular dynamics (MD) simulations were carried out with mouse AChE (mAChE, type of AChE1), Torpedo californica AChE (TcAChE, type of AChE1), and Drosophila melanogaster AChE (DmAChE, type of AChE2) bound with syn1-TZ2PA6 and anti1-TZ2PA6 isomers. Within the structure of the inhibitor, the 3,8-diamino-6-phenylphenanthridinium subunit and 9-amino-1,2,3,4-tetrahydroacridine subunit, via π-π interactions, made more favorable contributions to syn1-TZ2PA6 or anti1-TZ2PA6 isomer binding in the mAChE/TcAChE enzyme than the 1,2,3-triazole subunit. Compared to AChE1, the triazole subunit had increased binding energy with AChE2 due to a greater negative charge in the active site. The binding free energy calculated using the MM/PBSA method suggests that selectivity between AChE1 and AChE2 is mainly attributed to decreased binding affinity for the inhibitor. PMID:23500627

  11. IL-4 in vitro production is upregulated in Alzheimer's disease patients treated with acetylcholinesterase inhibitors.

    PubMed

    Lugaresi, Alessandra; Di Iorio, Angelo; Iarlori, Carla; Reale, Marcella; De Luca, Giovanna; Sparvieri, Eleonora; Michetti, Alessia; Conti, Pio; Gambi, Domenico; Abate, Giuseppe; Paganelli, Roberto

    2004-04-01

    Cytokines appear to be involved in the pathogenesis of Alzheimer's Disease (AD). Their modulation by treatment has been investigated only in a few studies. The aim of our study was to evaluate the effect of acetylcholinesterase inhibitors (AChEI) on Interleukin-4 (IL-4) production in AD patients. IL-4 levels were measured by ELISA on peripheral blood mononuclear cell cultures in the presence or absence of Concanavalin A or Phytohaemagglutinin. Linear regression analysis shows that patients who have been treated, have higher levels of IL-4 independently from age, gender and comorbidity. The increased production of IL-4 in AChEI treated patients might represent an additional mechanism through which AChEI act on AD progression. PMID:15050302

  12. ROMA: Representation and Quantification of Module Activity from Target Expression Data

    PubMed Central

    Martignetti, Loredana; Calzone, Laurence; Bonnet, Eric; Barillot, Emmanuel; Zinovyev, Andrei

    2016-01-01

    In many analyses of high-throughput data in systems biology, there is a need to quantify the activity of a set of genes in individual samples. A typical example is the case where it is necessary to estimate the activity of a transcription factor (which is often not directly measurable) from the expression of its target genes. We present here ROMA (Representation and quantification Of Module Activities) Java software, designed for fast and robust computation of the activity of gene sets (or modules) with coordinated expression. ROMA activity quantification is based on the simplest uni-factor linear model of gene regulation that approximates the expression data of a gene set by its first principal component. The proposed algorithm implements novel functionalities: it provides several method modifications for principal components computation, including weighted, robust and centered methods; it distinguishes overdispersed modules (based on the variance explained by the first principal component) and coordinated modules (based on the significance of the spectral gap); finally, it computes statistical significance of the estimated module overdispersion or coordination. ROMA can be applied in many contexts, from estimating differential activities of transcriptional factors to finding overdispersed pathways in single-cell transcriptomics data. We describe here the principles of ROMA providing several practical examples of its use. ROMA source code is available at https://github.com/sysbio-curie/Roma. PMID:26925094

  13. Cloning of Two Acetylcholinesterase Genes and Analysis of Point Mutations Putatively Associated with Triazophos Resistance in Chilo auricilius (Lepidoptera: Pyralidae).

    PubMed

    Luo, Guang-Hua; Li, Xiao-Huan; Zhang, Zhi-Chun; Liu, Bao-Sheng; Huang, Shui-Jin; Fang, Ji-Chao

    2015-06-01

    Acetylcholinesterase (AChE) is the target of organophosphate (OP) and carbamate insecticides. Mutations in the AChE gene (ace) leading to decreased insecticide susceptibility is the main resistance mechanism in insects. In this study, two Chilo auricilius acetylcholinesterase genes, designated as Caace1 and Caace2, were cloned using RT-PCR and RACE. Caace1 cDNA is 2534 bp, with ORF of 2082 bp, and it encodes an acetylcholinesterase 1 (CaAChE1) protein comprising a calculated 693 amino acid (aa) residues. Caace2 cDNA contains 2280 bp, with a full-length ORF of 1917 bp, encoding acetylcholinesterase 2 (CaAChE2) comprising a calculated 638 aa residues. At the aa level, CaAChE1 displays the highest similarity (97%) with the Chilo suppressalis AChE1, and CaAChE2 shows the highest similarity with the C. suppressalis AChE2 (99%). From the restriction fragment length polymorphism (RFLP) PCR (RFLP-PCR) analysis, one mutation in Caace1, similar to the ace1 mutation associated with triazophos resistance in C. suppressalis, was detected. Detailed examination of field populations of C. auricilius indicated this resistance mutation in C. auricilius is still quite infrequent. Based on the assay of AChE activity and RFLP-PCR testing, an individual that contains resistance mutation has lower AChE activities, while the individual that does not contain the resistance mutation has higher AChE activities. This study provides a basis for future investigations into the mechanism of OP resistance in C. auricilius, as well as a guidance for C. auricilius control with reasonable choice of pesticides. PMID:26470257

  14. Learning new gait patterns: Exploratory muscle activity during motor learning is not predicted by motor modules.

    PubMed

    Ranganathan, Rajiv; Krishnan, Chandramouli; Dhaher, Yasin Y; Rymer, William Z

    2016-03-21

    The motor module hypothesis in motor control proposes that the nervous system can simplify the problem of controlling a large number of muscles in human movement by grouping muscles into a smaller number of modules. Here, we tested one prediction of the modular organization hypothesis by examining whether there is preferential exploration along these motor modules during the learning of a new gait pattern. Healthy college-aged participants learned a new gait pattern which required increased hip and knee flexion during the swing phase while walking in a lower-extremity robot (Lokomat). The new gait pattern was displayed as a foot trajectory in the sagittal plane and participants attempted to match their foot trajectory to this template. We recorded EMG from 8 lower-extremity muscles and we extracted motor modules during both baseline walking and target-tracking using non-negative matrix factorization (NMF). Results showed increased trajectory variability in the first block of learning, indicating that participants were engaged in exploratory behavior. Critically, when we examined the muscle activity during this exploratory phase, we found that the composition of motor modules changed significantly within the first few strides of attempting the new gait pattern. The lack of persistence of the motor modules under even short time scales suggests that motor modules extracted during locomotion may be more indicative of correlated muscle activity induced by the task constraints of walking, rather than reflecting a modular control strategy. PMID:26916510

  15. Sug1 modulates yeast transcription activation by Cdc68.

    PubMed Central

    Xu, Q; Singer, R A; Johnston, G C

    1995-01-01

    The Cdc68 protein is required for the transcription of a variety of genes in the yeast Saccharomyces cerevisiae. In a search for proteins involved in the activity of the Cdc68 protein, we identified four suppressor genes in which mutations reverse the temperature sensitivity caused by the cdc68-1 allele. We report here the molecular characterization of mutations in one suppressor gene, the previously identified SUG1 gene. The Sug1 protein has been implicated in both transcriptional regulation and proteolysis. sug1 suppressor alleles reversed most aspects of the cdc68-1 mutant phenotype but did not suppress the lethality of a cdc68 null allele, indicating that sug1 suppression is by restoration of Cdc68 activity. Our evidence suggests that suppression by sug1 is unlikely to be due to increased stability of mutant Cdc68 protein, despite the observation that Sug1 affected proteolysis of mutant Cdc68. We report here that attenuated Sug1 activity strengthens mutant Cdc68 activity, whereas increased Sug1 activity further inhibits enfeebled Cdc68 activity, suggesting that Sug1 antagonizes the activator function of Cdc68 for transcription. Consistent with this hypothesis, we find that Sug1 represses transcription in vivo. PMID:7565755

  16. Acetylcholinesterase of the sand fly, Phlebotomus papatasi (Scopoli): cDNA sequence, baculovirus expression, and biochemical properties

    PubMed Central

    2013-01-01

    L. longipalpis. Recombinant P. papatasi AChE1 was expressed in the baculovirus system and characterized as an insect acetylcholinesterase with substrate preference for acetylthiocholine and inhibition at high substrate concentration. Enzyme activity was strongly inhibited by eserine, BW284c51, malaoxon, and paraoxon, and was insensitive to the butyrylcholinesterase inhibitors ethopropazine and iso-OMPA. Conclusions Results presented here enable the screening and identification of PpAChE mutations resulting in the genotype for insensitive PpAChE. Use of the recombinant P. papatasi AChE1 will facilitate rapid in vitro screening to identify novel PpAChE inhibitors, and comparative studies on biochemical kinetics of inhibition. PMID:23379291

  17. A Mechanism-based 3D-QSAR Approach for Classification and Prediction of Acetylcholinesterase Inhibitory Potency of Organophosphate and Carbamate Analogs

    EPA Science Inventory

    Organophosphate (OP) and carbamate esters can inhibit acetylcholinesterase (AChE) by binding covalently to a serine residue in the enzyme active site, and their inhibitory potency depends largely on affinity for the enzyme and the reactivity of the ester. Despite this understandi...

  18. Pharmacokinetics and pharmacodynamics of a novel Acetylcholinesterase Inhibitor, DMNG-3.

    PubMed

    Xin-Guo, Zhang; Kou, Fei; Guo-Di, Ma; Tang, Peng; Zhong-Duo, Yang

    2016-01-01

    DMNG-3(3β-Methyl-[2-(4-nitrophenoxy)ethyl]-amino]con-5-enine), is a new and the potentially most potent acetylcholinesterase inhibitor recently obtained from conessine by N-demethylation and nucleophilic substitution reaction. In the present study, a step-down passive avoidance test was used to investigate whether DMNG-3 could modulate impairment of learning and memory induced by scopolamine, and a high performance liquid chromatography(HPLC) method for the determination of DMNG-3 in biological samples was applied to study its pharmacokinetics and tissues distribution. Separation was achieved on C18 column using a mobile phase consisting methanol-water (70:30, v/v) at a flow rate of 1.0ml/min. The intra- and inter-day precisions were good and the RSD was all lower than 1.30%. The mean absolute recovery of DMNG-3 in plasma ranged from 88.55 to 96.45 %. Our results showed oral administration of DMNG-3(10,25,50 mg/kg/day) can significantly improve the latency and number of errors and had a positive effect of improvement of learning and memory in mice in passive avoidance tests. The elimination half-life (T1/2) was 14.07±1.29, 15.87±1.03h, and the total clearance (CL) values were 0.70±0.11, 0.78±0.13 L/h/kg, respectively. The pharmacokinetic studies showed that DMNG-3 has a slowly clearance and large distribution volume in experimental animals, and its disposition is linear over the range of doses tested. The liver, small intestine, stomach, and large intestine were the major distribution tissues of DMNG-3 in mice. It was found that DMNG-3 could be detected in brain, suggesting that DMNG-3 can cross the blood-brain barrier. The present study shows that DMNG-3 can be possible developed as a new drug for the treatment of Alzheimer's disease in the future. PMID:27373949

  19. Reward sensitivity modulates brain activity in the prefrontal cortex, ACC and striatum during task switching.

    PubMed

    Fuentes-Claramonte, Paola; Ávila, César; Rodríguez-Pujadas, Aina; Ventura-Campos, Noelia; Bustamante, Juan C; Costumero, Víctor; Rosell-Negre, Patricia; Barrós-Loscertales, Alfonso

    2015-01-01

    Current perspectives on cognitive control acknowledge that individual differences in motivational dispositions may modulate cognitive processes in the absence of reward contingencies. This work aimed to study the relationship between individual differences in Behavioral Activation System (BAS) sensitivity and the neural underpinnings involved in processing a switching cue in a task-switching paradigm. BAS sensitivity was hypothesized to modulate brain activity in frontal regions, ACC and the striatum. Twenty-eight healthy participants underwent fMRI while performing a switching task, which elicited activity in fronto-striatal regions during the processing of the switch cue. BAS sensitivity was negatively associated with activity in the lateral prefrontal cortex, anterior cingulate cortex and the ventral striatum. Combined with previous results, our data indicate that BAS sensitivity modulates the neurocognitive processes involved in task switching in a complex manner depending on task demands. Therefore, individual differences in motivational dispositions may influence cognitive processing in the absence of reward contingencies. PMID:25875640

  20. Reward Sensitivity Modulates Brain Activity in the Prefrontal Cortex, ACC and Striatum during Task Switching

    PubMed Central

    Fuentes-Claramonte, Paola; Ávila, César; Rodríguez-Pujadas, Aina; Ventura-Campos, Noelia; Bustamante, Juan C.; Costumero, Víctor; Rosell-Negre, Patricia; Barrós-Loscertales, Alfonso

    2015-01-01

    Current perspectives on cognitive control acknowledge that individual differences in motivational dispositions may modulate cognitive processes in the absence of reward contingencies. This work aimed to study the relationship between individual differences in Behavioral Activation System (BAS) sensitivity and the neural underpinnings involved in processing a switching cue in a task-switching paradigm. BAS sensitivity was hypothesized to modulate brain activity in frontal regions, ACC and the striatum. Twenty-eight healthy participants underwent fMRI while performing a switching task, which elicited activity in fronto-striatal regions during the processing of the switch cue. BAS sensitivity was negatively associated with activity in the lateral prefrontal cortex, anterior cingulate cortex and the ventral striatum. Combined with previous results, our data indicate that BAS sensitivity modulates the neurocognitive processes involved in task switching in a complex manner depending on task demands. Therefore, individual differences in motivational dispositions may influence cognitive processing in the absence of reward contingencies. PMID:25875640

  1. Acetylcholinesterase Inhibition by Biofumigant (Coumaran) from Leaves of Lantana camara in Stored Grain and Household Insect Pests

    PubMed Central

    Raghavendra, Anjanappa; Bakthavatsalam, Nandagopal

    2014-01-01

    Recent studies proved that the biofumigants could be an alternative to chemical fumigants against stored grain insect pests. For this reason, it is necessary to understand the mode of action of biofumigants. In the present study the prospectus of utilising Lantana camara as a potent fumigant insecticide is being discussed. Inhibition of acetylcholinesterase (AChE) by Coumaran, an active ingredient extracted from the plant L. camara, was studied. The biofumigant was used as an enzyme inhibitor and acetylthiocholine iodide as a substrate along with Ellman's reagent to carry out the reactions. The in vivo inhibition was observed in both dose dependent and time dependent in case of housefly, and the nervous tissue (ganglion) and the whole insect homogenate of stored grain insect exposed to Coumaran. The possible mode of action of Coumaran as an acetylcholinesterase inhibitor is discussed. PMID:25025036

  2. Acetylcholinesterase inhibition by biofumigant (Coumaran) from leaves of Lantana camara in stored grain and household insect pests.

    PubMed

    Rajashekar, Yallappa; Raghavendra, Anjanappa; Bakthavatsalam, Nandagopal

    2014-01-01

    Recent studies proved that the biofumigants could be an alternative to chemical fumigants against stored grain insect pests. For this reason, it is necessary to understand the mode of action of biofumigants. In the present study the prospectus of utilising Lantana camara as a potent fumigant insecticide is being discussed. Inhibition of acetylcholinesterase (AChE) by Coumaran, an active ingredient extracted from the plant L. camara, was studied. The biofumigant was used as an enzyme inhibitor and acetylthiocholine iodide as a substrate along with Ellman's reagent to carry out the reactions. The in vivo inhibition was observed in both dose dependent and time dependent in case of housefly, and the nervous tissue (ganglion) and the whole insect homogenate of stored grain insect exposed to Coumaran. The possible mode of action of Coumaran as an acetylcholinesterase inhibitor is discussed. PMID:25025036

  3. Hypothalamic modulation of splenic natural killer cell activity in rats.

    PubMed Central

    Katafuchi, T; Ichijo, T; Take, S; Hori, T

    1993-01-01

    1. The cytotoxic activity of splenic natural killer cells measured by a standard chromium release assay in urethane and alpha-chloralose-anaesthetized rats was significantly suppressed 20 min after bilateral ablation of the medial part of the preoptic hypothalamus (MPO). The suppression was completely blocked by prior splenic denervation. The splenic natural killer cell activity of MPO sham-lesioned rats or thalamus-lesioned rats, both having an intact splenic innervation, were not different from that of a non-treated control group. 2. Electrical stimulation of the bilateral MPO (0.1 ms, 0.1-0.3 mA, 5-100 Hz) suppressed the efferent activity of the splenic nerve in all six rats examined. The reduction of the nerve activity was accompanied by a transient fall in blood pressure. An I.V. injection of phenylephrine (3 micrograms/0.3 ml) also evoked a suppression of the nerve activity, which was accompanied by transient hypertension, suggesting that the suppressive effect of the MPO stimulation was independent of changes in blood pressure. On the other hand, a bilateral lesion of the MPO resulted in a sustained increase in the electrical activity of the splenic sympathetic nerve filaments which lasted for more than 2 h. 3. Microinjection of monosodium-L-glutamate (0.1 and 0.01 M in 0.1 microliters saline) unilaterally into the MPO evoked a transient suppression of the efferent discharge rate of the splenic nerve activity within 1 min, which was also accompanied by a decrease in blood pressure. The injection of saline (0.1 microliter) into the MPO had no effect. The microinjection of recombinant human interferon-alpha (200 and 2000 U in 0.1 microliter saline) into the MPO dose dependently increased the splenic nerve activity without any change in blood pressure. 4. In contrast, microinjection of interferon-alpha into the paraventricular nucleus of the hypothalamus (PVN) had no effect on splenic nerve activity, although an injection of glutamate increased the nerve

  4. Fuzzy Behavior Modulation with Threshold Activation for Autonomous Vehicle Navigation

    NASA Technical Reports Server (NTRS)

    Tunstel, Edward

    2000-01-01

    This paper describes fuzzy logic techniques used in a hierarchical behavior-based architecture for robot navigation. An architectural feature for threshold activation of fuzzy-behaviors is emphasized, which is potentially useful for tuning navigation performance in real world applications. The target application is autonomous local navigation of a small planetary rover. Threshold activation of low-level navigation behaviors is the primary focus. A preliminary assessment of its impact on local navigation performance is provided based on computer simulations.

  5. Thermal Analysis of ISS Service Module Active TCS

    NASA Technical Reports Server (NTRS)

    Altov, Vladimir V.; Zaletaev, Sergey V.; Belyavskiy, Evgeniy P.

    2000-01-01

    ISS Service Module mission must begin in July 2000. The verification of design thermal requirements is mostly due to thermal analysis. The thermal analysis is enough difficult problem because of large number of ISS configurations that had to be investigated and various orbital environments. Besides the ISS structure has articulating parts such as solar arrays and radiators. The presence of articulating parts greatly increases computation times and requires accurate approach to organization of calculations. The varying geometry needs us to calculate the view factors several times during the orbit, while in static geometry case we need do it only once. In this paper we consider the thermal mathematical model of SM that includes the TCS and construction thermal models and discuss the results of calculations for ISS configurations 1R and 9Al. The analysis is based on solving the nodal heat balance equations for ISS structure by Kutta-Merson method and analytical solutions of heat transfer equations for TCS units. The computations were performed using thermal software TERM [1,2] that will be briefly described.

  6. Modulation of Motor Area Activity during Observation of Unnatural Body Movements

    ERIC Educational Resources Information Center

    Shimada, Sotaro; Oki, Kazuma

    2012-01-01

    The mirror neuron system (MNS) is activated when observing the actions of others. However, it remains unclear whether the MNS responds more strongly to natural bodily actions in the observer's motor repertoire than to unnatural actions. We investigated whether MNS activity is modulated by the unnaturalness of an observed action by inserting short…

  7. Modulation of spontaneous fMRI activity in human visual cortex by behavioral state

    PubMed Central

    Bianciardi, Marta; Fukunaga, Masaki; van Gelderen, Peter; Horovitz, Silvina G.; de Zwart, Jacco A.; Duyn, Jeff H.

    2009-01-01

    The phenomenon of spontaneous fMRI activity is increasingly being exploited to investigate the connectivity of functional networks in human brain with high spatial-resolution. Although mounting evidence points towards a neuronal contribution to this activity, its functional role and dependence on behavioral state remain unclear. In this work, we used BOLD fMRI at 7 T to study the modulation of spontaneous activity in occipital areas by various behavioral conditions, including resting with eyes closed, eyes open with visual fixation, and eyes open with fixation and focal visual stimulation. Spontaneous activity was separated from evoked activity and from signal fluctuations related to cardiac and respiratory cycles. We found that spontaneous activity in visual areas was substantially reduced (amplitude (44%) and coherence (25%)) with the fixation conditions relative to the eyes-closed condition. No significant further modulation was observed when the visual stimulus was added. The observed dependence on behavioral condition suggests that part of spontaneous fMRI signal fluctuations represents neuronal activity. Possible mechanisms for the modulation of spontaneous activity by behavioral state are discussed. The observed linear superposition of spontaneous fMRI activity with focal evoked activity related to visual processing has important implications for fMRI studies, which ideally should take into account the effect of spontaneous activity to properly define brain activations during task conditions. PMID:19028588

  8. Modulation of the protein kinase activity of mTOR.

    PubMed

    Lawrence, J C; Lin, T A; McMahon, L P; Choi, K M

    2004-01-01

    mTOR is a founding member of a family of protein kinases having catalytic domains homologous to those in phosphatidylinositol 3-OH kinase. mTOR participates in the control by insulin of the phosphorylation of lipin, which is required for adipocyte differentiation, and the two translational regulators, p70S6K and PHAS-I. The phosphorylation of mTOR, itself, is stimulated by insulin in Ser2448, a site that is also phosphorylated by protein kinase B (PKB) in vitro and in response to activation of PKB activity in vivo. Ser2448 is located in a short stretch of amino acids not found in the two TOR proteins in yeast. A mutant mTOR lacking this stretch exhibited increased activity, and binding of the antibody, mTAb-1, to this region markedly increased mTOR activity. In contrast, rapamycin-FKBP12 inhibited mTOR activity towards both PHAS-I and p70S6K, although this complex inhibited the phosphorylation of some sites more than that of others. Mutating Ser2035 to Ile in the FKBP12-rapamycin binding domain rendered mTOR resistant to inhibition by rapamycin. Unexpectedly, this mutation markedly decreased the ability of mTOR to phosphorylate certain sites in both PHAS-I and p70S6K. The results support the hypotheses that rapamycin disrupts substrate recognition instead of directly inhibiting phosphotransferase activity and that mTOR activity in cells is controlled by the phosphorylation of an inhibitory regulatory domain containing the mTAb-1 epitope. PMID:14560959

  9. Acetylcholinesterase is associated with a decrease in cell proliferation of hepatocellular carcinoma cells.

    PubMed

    Pérez-Aguilar, Benjamín; Vidal, Cecilio J; Palomec, Guillermina; García-Dolores, Fernando; Gutiérrez-Ruiz, María Concepción; Bucio, Leticia; Gómez-Olivares, José Luis; Gómez-Quiroz, Luis Enrique

    2015-07-01

    Acetylcholinesterase (AChE), the enzyme that rapidly splits acetylcholine into acetate and choline, presents non-cholinergic functions through which may participate in the control of cell proliferation and apoptosis. These two features are relevant in cancer, particularly in hepatocellular carcinoma (HCC), a very aggressive liver tumor with high incidence and poor prognosis in advanced stages. Here we explored the relation between acetylcholinesterase and HCC growth by testing the influence of AChE on proliferation of Huh-7 and HepG2 cell lines, addressed in monolayer cultures, spheroid formation and human liver tumor samples. Results showed a clear relation in AChE expression and cell cycle progression, an effect which depended on cell confluence. Inhibition of AChE activity led to an increase in cell proliferation, which was associated with downregulation of p27 and cyclins. The fact that Huh-7 and HepG2 cell lines provided similar results lent weight to the relationship of AChE expression with cell cycle progression in hepatoma cell lines at least. Human liver tumor samples exhibited a decrease in AChE activity as compared with normal tissue. The evidence presented herein provides additional support for the proposed tumor suppressor role of AChE, which makes it a potential therapeutic target in therapies against hepatocellular carcinoma. PMID:25869328

  10. Amperometric biosensing of organophosphate and organocarbamate pesticides utilizing polypyrrole entrapped acetylcholinesterase electrode.

    PubMed

    Dutta, Rekha Rani; Puzari, Panchanan

    2014-02-15

    The work presented here describes a novel, easy and low-cost method of fabrication of a highly sensitive acetylcholinesterase biosensor and its application to detect organophosphate and organocarbamate pesticides. Acetylcholinesterase was electro-immobilized into a thick conducting layer of polypyrrole. Porcine skin gelatin and gluteraldehyde mixture was used for stabilizing the system. Acetylthiocholine chloride was used as the substrate. Polypyrrole catalyzed the electrochemical oxidation of thiocholine and promoted the electron transfer, thus lowering the oxidation potential and increasing the detection sensitivity. Electro oxidation of thiocholine in polypyrrole matrix occurred at 0.1 V under low potential scan rate. The thiocholine sensitivity of the electrode was found to be 143 mA/M. The sensor was applied to detect the sample organophosphate pesticide ethylparaoxon and organocarbamate pesticide carbofuran. The detection limit for paraoxon was found to be 1.1 ppb and that for carbofuran is 0.12 ppb. The sensor showed good intra and inter state precision with relative standard deviation (RSD) 0.742% and 6.56% respectively. Both dry and wet storage stability were studied. The sensor stored at 0°C in dry condition had a good storage stability retaining 70% of its original activity for 4 months. During wet storage, the activity decrease followed the same trend, however, the operational stability at the end of the storage period was found to be less compared to the dry storage case. The developed biosensor is as a promising new tool for analysis of cholinesterase inhibitors. PMID:24041663

  11. Acetylcholinesterase from Human Erythrocytes as a Surrogate Biomarker of Lead Induced Neurotoxicity

    PubMed Central

    Gupta, Vivek Kumar; Pal, Rajnish; Siddiqi, Nikhat Jamal; Sharma, Bechan

    2015-01-01

    Lead induced neurotoxicity in the people engaged in different occupations has received wide attention but very little studies have been carried out to monitor occupational neurotoxicity directly due to lead exposure using biochemical methods. In the present paper an endeavour has been made in order to assess the lead mediated neurotoxicity by in vitro assay of the activity of acetylcholinesterase (AChE) from human erythrocytes in presence of different concentrations of lead. The results suggested that the activity of this enzyme was localized in membrane bound fraction and it was found to be highly stable up to 30 days when stored at −20°C in phosphate buffer (50 mM, pH 7.4) containing 0.2% Triton X-100. The erythrocyte's AChE exhibited Km for acetylcholinesterase to be 0.1 mM. Lead caused sharp inhibition of the enzyme and its IC50 value was computed to be 1.34 mM. The inhibition of the enzyme by lead was found to be of uncompetitive type (Ki value, 3.6 mM) which negatively influenced both the Vmax and the enzyme-substrate binding affinity. Taken together, these results indicate that AChE from human erythrocytes could be exploited as a surrogate biomarker of lead induced neurotoxicity particularly in the people occupationally exposed to lead. PMID:26600946

  12. Acetylcholinesterase from Human Erythrocytes as a Surrogate Biomarker of Lead Induced Neurotoxicity.

    PubMed

    Gupta, Vivek Kumar; Pal, Rajnish; Siddiqi, Nikhat Jamal; Sharma, Bechan

    2015-01-01

    Lead induced neurotoxicity in the people engaged in different occupations has received wide attention but very little studies have been carried out to monitor occupational neurotoxicity directly due to lead exposure using biochemical methods. In the present paper an endeavour has been made in order to assess the lead mediated neurotoxicity by in vitro assay of the activity of acetylcholinesterase (AChE) from human erythrocytes in presence of different concentrations of lead. The results suggested that the activity of this enzyme was localized in membrane bound fraction and it was found to be highly stable up to 30 days when stored at -20°C in phosphate buffer (50 mM, pH 7.4) containing 0.2% Triton X-100. The erythrocyte's AChE exhibited K m for acetylcholinesterase to be 0.1 mM. Lead caused sharp inhibition of the enzyme and its IC50 value was computed to be 1.34 mM. The inhibition of the enzyme by lead was found to be of uncompetitive type (K i value, 3.6 mM) which negatively influenced both the V max and the enzyme-substrate binding affinity. Taken together, these results indicate that AChE from human erythrocytes could be exploited as a surrogate biomarker of lead induced neurotoxicity particularly in the people occupationally exposed to lead. PMID:26600946

  13. Phospholipase Cε Modulates Rap1 Activity and the Endothelial Barrier.

    PubMed

    DiStefano, Peter V; Smrcka, Alan V; Glading, Angela J

    2016-01-01

    The phosphoinositide-specific phospholipase C, PLCε, is a unique signaling protein with known roles in regulating cardiac myocyte growth, astrocyte inflammatory signaling, and tumor formation. PLCε is also expressed in endothelial cells, however its role in endothelial regulation is not fully established. We show that endothelial cells of multiple origins, including human pulmonary artery (HPAEC), human umbilical vein (HUVEC), and immortalized brain microvascular (hCMEC/D3) endothelial cells, express PLCε. Knockdown of PLCε in arterial endothelial monolayers decreased the effectiveness of the endothelial barrier. Concomitantly, RhoA activity and stress fiber formation were increased. PLCε-deficient arterial endothelial cells also exhibited decreased Rap1-GTP levels, which could be restored by activation of the Rap1 GEF, Epac, to rescue the increase in monolayer leak. Reintroduction of PLCε rescued monolayer leak with both the CDC25 GEF domain and the lipase domain of PLCε required to fully activate Rap1 and to rescue endothelial barrier function. Finally, we demonstrate that the barrier promoting effects PLCε are dependent on Rap1 signaling through the Rap1 effector, KRIT1, which we have previously shown is vital for maintaining endothelial barrier stability. Thus we have described a novel role for PLCε PIP2 hydrolytic and Rap GEF activities in arterial endothelial cells, where PLCε-dependent activation of Rap1/KRIT1 signaling promotes endothelial barrier stability. PMID:27612188

  14. Valsalva maneuver: Insights into baroreflex modulation of human sympathetic activity

    NASA Technical Reports Server (NTRS)

    Smith, Michael L.; Eckberg, Dwain L.; Fritsch, Janice M.; Beightol, Larry A.; Ellenbogen, Kenneth A.

    1991-01-01

    Valsalva's maneuver, voluntary forced expiration against a closed glottis, is a well-characterized research tool, used to assess the integrity of human autonomic cardiovascular control. Valsalva straining provokes a stereotyped succession of alternating positive and negative arterial pressure and heart rate changes mediated in part by arterial baroreceptors. Arterial pressure changes result primarily from fluctuating levels of venous return to the heart and changes of sympathetic nerve activity. Muscle sympathetic activity was measured directly in nine volunteers to explore quantitatively the relation between arterial pressure and human sympathetic outflow during pressure transients provoked by controlled graded Valsalva maneuvers. Our results underscore several properties of sympathetic regulation during Valsalva straining. First, muscle sympathetic nerve activity changes as a mirror image of changes in arterial pressure. Second, the magnitude of sympathetic augmentation during Valsalva straining predicts phase 4 arterial pressure elevations. Third, post-Valsalva sympathetic inhibition persists beyond the return of arterial and right atrial pressures to baseline levels which reflects an alteration of the normal relation between arterial pressure and muscle sympathetic activity. Therefore, Valsalva straining may have some utility for investigating changes of reflex control of sympathetic activity after space flight; however, measurement of beat-to-beat arterial pressure is essential for this use. The utility of this technique in microgravity can not be determined from these data. Further investigations are necessary to determine whether these relations are affected by the expansion of intrathoracic blood volume associated with microgravity.

  15. Cell proliferation in vitro modulates fibroblast collagenase activity

    SciTech Connect

    Lindblad, W.J.; Flood, L.

    1986-05-01

    Collagenase enzyme activity is regulated by numerous control mechanisms which prevent excessive release and activation of this protease. A primary mechanism for regulating enzyme extracellular activity may be linked to cell division, therefore they have examined the release of collagenase by fibroblasts in vitro in response to cellular proliferation. Studies were performed using fibroblasts derived from adult rat dermis maintained in DMEM containing 10% newborn calf serum, 25 mM tricine buffer, and antibiotics. Cells between subculture 10 and 19 were used with enzyme activity determined with a /sup 14/C-labelled soluble Type I collagen substrate with and without trypsin activation. Fibroblasts, trypsinized and plated at low density secreted 8.5 fold more enzyme than those cells at confluence (975 vs. 115 dpm/..mu..g DNA). This diminution occurred gradually as the cells went from logrithmic growth towards confluence. Confluent fibroblast monolayers were scraped in a grid arrangement, stimulating the remaining cells to divide, without exposure to trypsin. Within 24-48 hr postscraping enzyme levels had increased 260-400%, accompanied by enhanced incorporation of /sup 3/H-thymidine and /sup 3/H-uridine into cell macromolecules. The burst of enzyme release began to subside 12 hr later. These results support a close relationship between fibroblast proliferation and collagenase secretion.

  16. Preclinical and first-in-human evaluation of PRX-105, a PEGylated, plant-derived, recombinant human acetylcholinesterase-R.

    PubMed

    Atsmon, Jacob; Brill-Almon, Einat; Nadri-Shay, Carmit; Chertkoff, Raul; Alon, Sari; Shaikevich, Dimitri; Volokhov, Inna; Haim, Kirsten Y; Bartfeld, Daniel; Shulman, Avidor; Ruderfer, Ilya; Ben-Moshe, Tehila; Shilovitzky, Orit; Soreq, Hermona; Shaaltiel, Yoseph

    2015-09-15

    PRX-105 is a plant-derived recombinant version of the human 'read-through' acetylcholinesterase splice variant (AChE-R). Its active site structure is similar to that of the synaptic variant, and it displays the same affinity towards organophosphorus (OP) compounds. As such, PRX-105 may serve as a bio-scavenger for OP pesticides and chemical warfare agents. To assess its potential use in prophylaxis and treatment of OP poisoning we conducted several preliminary tests, reported in this paper. Intravenous (IV) PRX-105 was administered to mice either before or after exposure to an OP toxin. All mice who received an IV dose of 50nmol/kg PRX-105, 2min before being exposed to 1.33×LD50 and 1.5×LD50 of toxin and 10min after exposure to 1.5×LD50 survived. The pharmacokinetic and toxicity profiles of PRX-105 were evaluated in mice and mini-pigs. Following single and multiple IV doses (50 to 200mg/kg) no deaths occurred and no significant laboratory and histopathological changes were observed. The overall elimination half-life (t½) in mice was 994 (±173) min. Additionally, a first-in-human study, to assess the safety, tolerability and pharmacokinetics of the compound, was conducted in healthy volunteers. The t½ in humans was substantially longer than in mice (average 26.7h). Despite the small number of animals and human subjects who were assessed, the fact that PRX-105 exerts a protective and therapeutic effect following exposure to lethal doses of OP, its favorable safety profile and its relatively long half-life, renders it a promising candidate for treatment and prophylaxis against OP poisoning and warrants further investigation. PMID:26051873

  17. Regular exercise improves cardiac contractile activation by modulating MHC isoforms and SERCA activity in orchidectomized rats.

    PubMed

    Vutthasathien, Pavarana; Wattanapermpool, Jonggonnee

    2015-10-01

    Data from the trial known as Testosterone in Older Men with Mobility Limitations (TOM) has indicated an association between testosterone administration and a greater risk for adverse cardiovascular events. We therefore propose that regular exercise is a cardioprotective alternative that prevents detrimental changes in contractile activation when a deficiency in male sex hormones exists. Ten-week-old orchidectomized (ORX) rats were subjected to a 9-wk treadmill running program at moderate intensity starting 1 wk after surgery. Although exercise-induced cardiac hypertrophy was observed both in rats that underwent ORX and sham surgery, regular exercise enhanced cardiac myofilament Ca(2+) sensitivity and myosin light-chain 2 phosphorylation only in rats that underwent a sham operation. Although the rats that had sham surgery and and given exercise exhibited no change in maximum developed tension, regular running prevented the suppression of maximum active tension in the hearts of ORX rats. Regular exercise also prevented a shift in myosin heavy chain (MHC) isoforms toward β-MHC, a reduction in sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) activity, and an increase in SERCA sensitivity in the hearts of ORX rats. Neither SERCA content nor its modulating component, phospholamban (PLB), was altered by exercise in either sham-operated or ORX rats. However, decreases in the phosphorylated Thr(17) form of PLB and the phosphorylated Thr(287) form of Ca(2+)/calmodulin-dependent kinase II in the hearts of ORX rats were abolished after regular exercise. These results thus support the use of regular running as a cardioprotective alternative to testosterone replacement in hypogonadal conditions. PMID:26272317

  18. Activity-Dependent Modulation of Neural Circuit Synaptic Connectivity

    PubMed Central

    Tessier, Charles R.; Broadie, Kendal

    2009-01-01

    In many nervous systems, the establishment of neural circuits is known to proceed via a two-stage process; (1) early, activity-independent wiring to produce a rough map characterized by excessive synaptic connections, and (2) subsequent, use-dependent pruning to eliminate inappropriate connections and reinforce maintained synapses. In invertebrates, however, evidence of the activity-dependent phase of synaptic refinement has been elusive, and the dogma has long been that invertebrate circuits are “hard-wired” in a purely activity-independent manner. This conclusion has been challenged recently through the use of new transgenic tools employed in the powerful Drosophila system, which have allowed unprecedented temporal control and single neuron imaging resolution. These recent studies reveal that activity-dependent mechanisms are indeed required to refine circuit maps in Drosophila during precise, restricted windows of late-phase development. Such mechanisms of circuit refinement may be key to understanding a number of human neurological diseases, including developmental disorders such as Fragile X syndrome (FXS) and autism, which are hypothesized to result from defects in synaptic connectivity and activity-dependent circuit function. This review focuses on our current understanding of activity-dependent synaptic connectivity in Drosophila, primarily through analyzing the role of the fragile X mental retardation protein (FMRP) in the Drosophila FXS disease model. The particular emphasis of this review is on the expanding array of new genetically-encoded tools that are allowing cellular events and molecular players to be dissected with ever greater precision and detail. PMID:19668708

  19. Modulation of muscle sympathetic nerve activity by low-frequency physiological activation of the vestibular utricle in awake humans.

    PubMed

    Hammam, Elie; Kwok, Kenny; Macefield, Vaughan G

    2013-09-01

    We recently showed that selective stimulation of one set of otolithic organs-those located in the utricle, sensitive to displacement in the horizontal axis-causes a marked entrainment of skin sympathetic nerve activity (SSNA). Here, we assessed whether muscle sympathetic nerve activity (MSNA) is similarly modulated. MSNA was recorded via tungsten microelectrodes inserted into cutaneous fascicles of the common peroneal nerve in 12 awake subjects, seated (head vertical, eyes closed) on a motorised platform. Slow sinusoidal accelerations-decelerations (±4 mG) were applied in the X (antero-posterior) or Y (medio-lateral) direction at 0.08 Hz. Cross-correlation analysis revealed partial entrainment of MSNA: vestibular modulation was 32 ± 3 % for displacements in the X-axis and 29 ± 3 % in the Y-axis; these were significantly smaller than those evoked in SSNA (97 ± 3 and 91 ± 5 %, respectively). For each sinusoidal cycle, there were two peaks of modulation-one associated with acceleration as the platform moved forward or to the side and one associated with acceleration in the opposite direction. We believe the two peaks reflect inertial displacement of the stereocilia within the utricle during sinusoidal acceleration, which evokes vestibulosympathetic reflexes that are expressed as vestibular modulation of MSNA as well as of SSNA. The smaller vestibular modulation of MSNA can be explained by the dominant modulation of MSNA by the arterial baroreceptors. PMID:23852323

  20. How Orthography Modulates Morphological Priming: Subliminal Kanji Activation in Japanese

    PubMed Central

    Nakano, Yoko; Ikemoto, Yu; Jacob, Gunnar; Clahsen, Harald

    2016-01-01

    The current study investigates to what extent masked morphological priming is modulated by language-particular properties, specifically by its writing system. We present results from two masked priming experiments investigating the processing of complex Japanese words written in less common (moraic) scripts. In Experiment 1, participants performed lexical decisions on target verbs; these were preceded by primes which were either (i) a past-tense form of the same verb, (ii) a stem-related form with the epenthetic vowel -i, (iii) a semantically-related form, and (iv) a phonologically-related form. Significant priming effects were obtained for prime types (i), (ii), and (iii), but not for (iv). This pattern of results differs from previous findings on languages with alphabetic scripts, which found reliable masked priming effects for morphologically related prime/target pairs of type (i), but not for non-affixal and semantically-related primes of types (ii), and (iii). In Experiment 2, we measured priming effects for prime/target pairs which are neither morphologically, semantically, phonologically nor - as presented in their moraic scripts—orthographically related, but which—in their commonly written form—share the same kanji, which are logograms adopted from Chinese. The results showed a significant priming effect, with faster lexical-decision times for kanji-related prime/target pairs relative to unrelated ones. We conclude that affix-stripping is insufficient to account for masked morphological priming effects across languages, but that language-particular properties (in the case of Japanese, the writing system) affect the processing of (morphologically) complex words. PMID:27065895

  1. How Orthography Modulates Morphological Priming: Subliminal Kanji Activation in Japanese.

    PubMed

    Nakano, Yoko; Ikemoto, Yu; Jacob, Gunnar; Clahsen, Harald

    2016-01-01

    The current study investigates to what extent masked morphological priming is modulated by language-particular properties, specifically by its writing system. We present results from two masked priming experiments investigating the processing of complex Japanese words written in less common (moraic) scripts. In Experiment 1, participants performed lexical decisions on target verbs; these were preceded by primes which were either (i) a past-tense form of the same verb, (ii) a stem-related form with the epenthetic vowel -i, (iii) a semantically-related form, and (iv) a phonologically-related form. Significant priming effects were obtained for prime types (i), (ii), and (iii), but not for (iv). This pattern of results differs from previous findings on languages with alphabetic scripts, which found reliable masked priming effects for morphologically related prime/target pairs of type (i), but not for non-affixal and semantically-related primes of types (ii), and (iii). In Experiment 2, we measured priming effects for prime/target pairs which are neither morphologically, semantically, phonologically nor - as presented in their moraic scripts-orthographically related, but which-in their commonly written form-share the same kanji, which are logograms adopted from Chinese. The results showed a significant priming effect, with faster lexical-decision times for kanji-related prime/target pairs relative to unrelated ones. We conclude that affix-stripping is insufficient to account for masked morphological priming effects across languages, but that language-particular properties (in the case of Japanese, the writing system) affect the processing of (morphologically) complex words. PMID:27065895

  2. Calcium Modulation of Plant Plasma Membrane-Bound Atpase Activities

    NASA Technical Reports Server (NTRS)

    Caldwell, C.

    1983-01-01

    The kinetic properties of barley enzyme are discussed and compared with those of other plants. Possibilities for calcium transport in the plasma membrane by proton pump and ATPase-dependent calcium pumps are explored. Topics covered include the ph phase of the enzyme; high affinity of barley for calcium; temperature dependence, activation enthalpy, and the types of ATPase catalytic sites. Attention is given to lipids which are both screened and bound by calcium. Studies show that barley has a calmodulin activated ATPase that is found in the presence of magnesium and calcium.

  3. FEF-microstimulation causes task-dependent modulation of occipital fMRI activity.

    PubMed

    Premereur, Elsie; Janssen, Peter; Vanduffel, Wim

    2013-02-15

    Electrical microstimulation of FEF (FEF-EM) modulates neuronal activity in area V4 (Moore and Armstrong, 2003) and elicits functional magnetic resonance imaging (fMRI) activations in visual cortex in a bottom-up dependent manner (Ekstrom et al., 2008). Here we test the hypothesis that FEF-EM-induced modulations of fMRI activity are also function of task demands, which would suggest top-down dependent gating of FEF signals in early visual cortex. We scanned two monkeys performing a visually guided saccade task; a passive fixation task with a very similar visual display; and a passive fixation task without peripheral dots. We found increased effects of FEF-EM on fMRI-activity in visual cortex during saccades compared to fixation, indicating that the FEF-EM induced modulation is task-dependent. Finally, the effect of FEF-EM is mainly present in voxels which were less activated by visual stimuli in the absence of electrical stimulation. Our results show that the FEF-EM-induced pattern of activation in early visual cortex is topographically specific and more pronounced during increased task demands. These results fit with models suggesting that FEF is an important source modulating activity in early sensory cortex and that these influences can be enhanced by coincident bottom-up or top-down signals. PMID:23186918

  4. Involvement of acetylcholinesterase and protein kinase C in the protective effect of caffeine against β-amyloid-induced alterations in red blood cells.

    PubMed

    Carelli-Alinovi, Cristiana; Ficarra, Silvana; Russo, Anna Maria; Giunta, Elena; Barreca, Davide; Galtieri, Antonio; Misiti, Francesco; Tellone, Ester

    2016-02-01

    It is well known the role of oxidative stress in the pathophysiology of Alzheimer's disease (AD) and of other neurodegenerative pathologies. We have previously documented that Amyloid beta peptide (1-42) (Abeta) dependent-oxidative modifications affect red blood cell (RBC) morphology and function. Experimental studies show that caffeine (CF) consumption is inversely correlated with AD. In this study, we investigated the role played by RBC in the protective mechanism elicited by CF against Abeta mediated toxicity. PS exposure levels by FACS analysis, as well as protein band 3 functionality analysis, indicated that CF at 100 μM protected against Abeta-mediated membrane alterations, which are known to occur in AD. Moreover, CF counteracts inhibition of ATP release from RBC by Abeta, restoring its ability to modulate vasodilation. Concurrently, analysis of protein kinase C (PKC) and caspase 3 activities, responsible for cytoskeleton alterations, revealed that unlike to caspase 3, PKCα activation induced by Abeta was fully abolished by CF through a mechanism involving Acetylcholinesterase (AChE), located on external face of RBC plasma membrane. These results provide support for the hypothesis concerning the protective role of CF in AD patients could include also a peripheral mechanism involving RBC. PMID:26620258

  5. Hsp90 Activity Modulation by Plant Secondary Metabolites.

    PubMed

    Dal Piaz, Fabrizio; Terracciano, Stefania; De Tommasi, Nunziatina; Braca, Alessandra

    2015-09-01

    Hsp90 is an evolutionarily conserved adenosine triphosphate-dependent molecular chaperone and is one of the most abundant proteins in the cells (1-3 %). Hsp90 is induced when a cell undergoes various types of environmental stresses such as heat, cold, or oxygen deprivation. It is involved in the turnover, trafficking, and activity of client proteins, including apoptotic factors, protein kinases, transcription factors, signaling proteins, and a number of oncoproteins. Most of the Hsp90 client proteins are involved in cell growth, differentiation, and survival, and include kinases, nuclear hormone receptors, transcription factors, and other proteins associated with almost all the hallmarks of cancer. Consistent with these diverse activities, genetic and biochemical studies have demonstrated the implication of Hsp90 in a range of diseases, including cancer, making this chaperone an interesting target for drug research.During the last few decades, plant secondary metabolites have been studied as a major source for lead compounds in drug discovery. Recently, several plant-derived small molecules have been discovered exhibiting inhibitory activity towards Hsp90, such as epigallocatechin gallate, gedunin, lentiginosine, celastrol, and deguelin. In this work, an overview of plant secondary metabolites interfering with Hsp90 activities is provided. PMID:26227505

  6. Social status modulates neural activity in the mentalizing network

    PubMed Central

    Muscatell, Keely A.; Morelli, Sylvia A.; Falk, Emily B.; Way, Baldwin M.; Pfeifer, Jennifer H.; Galinsky, Adam D.; Lieberman, Matthew D.; Dapretto, Mirella; Eisenberger, Naomi I.

    2013-01-01

    The current research explored the neural mechanisms linking social status to perceptions of the social world. Two fMRI studies provide converging evidence that individuals lower in social status are more likely to engage neural circuitry often involved in ‘mentalizing’ or thinking about others' thoughts and feelings. Study 1 found that college students' perception of their social status in the university community was related to neural activity in the mentalizing network (e.g., DMPFC, MPFC, precuneus/PCC) while encoding social information, with lower social status predicting greater neural activity in this network. Study 2 demonstrated that socioeconomic status, an objective indicator of global standing, predicted adolescents' neural activity during the processing of threatening faces, with individuals lower in social status displaying greater activity in the DMPFC, previously associated with mentalizing, and the amygdala, previously associated with emotion/salience processing. These studies demonstrate that social status is fundamentally and neurocognitively linked to how people process and navigate their social worlds. PMID:22289808

  7. Antihelminthic niclosamide modulates dendritic cells activation and function.

    PubMed

    Wu, Chieh-Shan; Li, Yi-Rong; Chen, Jeremy J W; Chen, Ying-Che; Chu, Chiang-Liang; Pan, I-Hong; Wu, Yu-Shan; Lin, Chi-Chen

    2014-01-01

    Dendritic cells (DCs) link the sensing of the environment by the innate immune system to the initiation of adaptive immune responses. Accordingly, DCs are considered to be a major target in the development of immunomodulating compounds. In this study, the effect of niclosamide, a Food and Drug Administration-approved antihelminthic drug, on the activation of lipopolysaccharide (LPS)-stimulated murine bone marrow-derived DCs was examined. Our experimental results show that niclosamide reduced the pro-inflammatory cytokine and chemokine expression of LPS-activated DCs. In addition, niclosamide also affected the expression of MHC and costimulatory molecules and influenced the ability of the cells to take up antigens. Therefore, in mixed cell cultures composed of syngeneic OVA-specific T cells and DCs, niclosamide-treated DCs showed a decreased ability to stimulate T cell proliferation and IFN-γ production. Furthermore, intravenous injection of niclosamide also attenuated contact hypersensitivity (CHS) in mice during sensitization with 2,4-dinitro-1-fluorobenzene. Blocking the LPS-induced activation of MAPK-ERK, JNK and NF-κB may contribute to the inhibitory effect of niclosamide on DC activation. Collectively, our findings suggest that niclosamide can manipulate the function of DCs. These results provide new insight into the immunopharmacological role of niclosamide and suggest that it may be useful for the treatment of chronic inflammatory disorders or DC-mediated autoimmune diseases. PMID:24561310

  8. Modulation of Erythrocyte Plasma Membrane Redox System Activity by Curcumin

    PubMed Central

    Singh, Prabhakar; Kesharwani, Rajesh Kumar; Misra, Krishna; Rizvi, Syed Ibrahim

    2016-01-01

    Plasma membrane redox system (PMRS) is an electron transport chain system ubiquitously present throughout all cell types. It transfers electron from intracellular substrates to extracellular acceptors for regulation of redox status. Curcumin, isolated from Curcuma longa, has modulatory effects on cellular physiology due to its membrane interaction ability and antioxidant potential. The present study investigates the effect of curcumin on PMRS activity of erythrocytes isolated from Wistar rats in vitro and in vivo and validated through an in silico docking simulation study using Molegro Virtual Docker (MVD). Effects of curcumin were also evaluated on level of glutathione (GSH) and the oxidant potential of plasma measured in terms of plasma ferric equivalent oxidative potentials (PFEOP). Results show that curcumin significantly (p < 0.01) downregulated the PMRS activity in a dose-dependent manner. Molecular docking results suggest that curcumin interacts with amino acids at the active site cavity of cytochrome b5 reductase, a key constituent of PMRS. Curcumin also increased the GSH level in erythrocytes and plasma while simultaneously decreasing the oxidant potential (PFEOP) of plasma. Altered PMRS activity and redox status are associated with the pathophysiology of several health complications including aging and diabetes; hence, the above finding may explain part of the role of curcumin in health beneficial effects. PMID:26904287

  9. ModuleBlast: identifying activated sub-networks within and across species

    PubMed Central

    Zinman, Guy E.; Naiman, Shoshana; O'Dee, Dawn M.; Kumar, Nishant; Nau, Gerard J.; Cohen, Haim Y.; Bar-Joseph, Ziv

    2015-01-01

    Identifying conserved and divergent response patterns in gene networks is becoming increasingly important. A common approach is integrating expression information with gene association networks in order to find groups of connected genes that are activated or repressed. In many cases, researchers are also interested in comparisons across species (or conditions). Finding an active sub-network is a hard problem and applying it across species requires further considerations (e.g. orthology information, expression data and networks from different sources). To address these challenges we devised ModuleBlast, which uses both expression and network topology to search for highly relevant sub-networks. We have applied ModuleBlast to expression and interaction data from mouse, macaque and human to study immune response and aging. The immune response analysis identified several relevant modules, consistent with recent findings on apoptosis and NFκB activation following infection. Temporal analysis of these data revealed cascades of modules that are dynamically activated within and across species. We have experimentally validated some of the novel hypotheses resulting from the analysis of the ModuleBlast results leading to new insights into the mechanisms used by a key mammalian aging protein. PMID:25428368

  10. ModuleBlast: identifying activated sub-networks within and across species.

    PubMed

    Zinman, Guy E; Naiman, Shoshana; O'Dee, Dawn M; Kumar, Nishant; Nau, Gerard J; Cohen, Haim Y; Bar-Joseph, Ziv

    2015-02-18

    Identifying conserved and divergent response patterns in gene networks is becoming increasingly important. A common approach is integrating expression information with gene association networks in order to find groups of connected genes that are activated or repressed. In many cases, researchers are also interested in comparisons across species (or conditions). Finding an active sub-network is a hard problem and applying it across species requires further considerations (e.g. orthology information, expression data and networks from different sources). To address these challenges we devised ModuleBlast, which uses both expression and network topology to search for highly relevant sub-networks. We have applied ModuleBlast to expression and interaction data from mouse, macaque and human to study immune response and aging. The immune response analysis identified several relevant modules, consistent with recent findings on apoptosis and NFκB activation following infection. Temporal analysis of these data revealed cascades of modules that are dynamically activated within and across species. We have experimentally validated some of the novel hypotheses resulting from the analysis of the ModuleBlast results leading to new insights into the mechanisms used by a key mammalian aging protein. PMID:25428368

  11. Left brain cortical activity modulates stress effects on social behavior.

    PubMed

    Lee, Eunee; Hong, Jiso; Park, Young-Gyun; Chae, Sujin; Kim, Yong; Kim, Daesoo

    2015-01-01

    When subjected to stress, some individuals develop maladaptive symptoms whereas others retain normal behavior. The medial prefrontal cortex (mPFC) is known to control these adaptive responses to stress. Here, we show that mPFC neurons in the left hemisphere control stress effects on social behavior. Mice made socially avoidant by the stress of chronic social defeats showed depressed neural activity in the left mPFC. Photoactivation of these neurons reversed social avoidance and restored social activity. Despite social defeats, resilient mice with normal sociability showed normal firing rates in the left mPFC; however, photoinhibition of these neurons induced social avoidance. The same photomodulation administered to the right mPFC caused no significant effects. These results explain how stressed individuals develop maladaptive behaviors through left cortical depression, as reported in mood and anxiety disorders. PMID:26302668

  12. Modulation of phospholipase A2 activity in human fibroblasts.

    PubMed Central

    Solito, E.; Parente, L.

    1989-01-01

    1. Human embryonic skin fibroblasts (HSF) incubated overnight with either human recombinant interleukin-1 alpha (rIL-1 alpha) or interleukin-1 beta (rIL-1 beta) released large amounts of prostaglandin E2 (PGE2). 2. rIL-1 beta, bradykinin (Bk) and arachidonic acid (AA) significantly stimulated PGE2 release from HSF incubated overnight in the presence of either interleukin. 3. Hydrocortisone inhibited the PGE2 release induced by rIL-1 beta and Bk, but not by AA. 4. The steroid inhibitory effect was reversed by actinomycin D as well as by an anti-lipocortin monoclonal antibody. 5. The results suggest that in HSF, rIL-1 beta is able to stimulate both cyclo-oxygenase and phospholipase A2 (PLA2) activity. 6. The stimulation of PLA2 activity by rIL-1 beta is inhibited by hydrocortisone, probably via induction of lipocortin-like proteins. PMID:2785834

  13. Language modulates brain activity underlying representation of kinship terms

    PubMed Central

    Wu, Haiyan; Ge, Yue; Tang, Honghong; Luo, Yue-Jia; Mai, Xiaoqin; Liu, Chao

    2015-01-01

    Kinship terms have been found to be highly diverse across languages. Here we investigated the brain representation of kinship terms in two distinct populations, native Chinese and Caucasian English speakers, with a five-element kinship identification (FEKI) task. The neuroimaging results showed a common extensive frontal and parietal lobe brain activation pattern for different kinship levels for both Chinese and Caucasian English speakers. Furthermore, Chinese speakers had longer reaction times and elicited more fronto-parietal brain networks activation compared to English speakers in level three (e.g., uncle and nephew) and four (e.g., cousin), including an association between the middle frontal gyrus and superior parietal lobe, which might be associated with higher working memory, attention control, and social distance representation load in Chinese kinship system processing. These results contribute to our understanding of the representation of kinship terms in the two languages. PMID:26685907

  14. Left brain cortical activity modulates stress effects on social behavior

    PubMed Central

    Lee, Eunee; Hong, Jiso; Park, Young-Gyun; Chae, Sujin; Kim, Yong; Kim, Daesoo

    2015-01-01

    When subjected to stress, some individuals develop maladaptive symptoms whereas others retain normal behavior. The medial prefrontal cortex (mPFC) is known to control these adaptive responses to stress. Here, we show that mPFC neurons in the left hemisphere control stress effects on social behavior. Mice made socially avoidant by the stress of chronic social defeats showed depressed neural activity in the left mPFC. Photoactivation of these neurons reversed social avoidance and restored social activity. Despite social defeats, resilient mice with normal sociability showed normal firing rates in the left mPFC; however, photoinhibition of these neurons induced social avoidance. The same photomodulation administered to the right mPFC caused no significant effects. These results explain how stressed individuals develop maladaptive behaviors through left cortical depression, as reported in mood and anxiety disorders. PMID:26302668

  15. MDMA (ecstasy) modulates locomotor and prefrontal cortex sensory evoked activity.

    PubMed

    Atkins, Kristal; Burks, Tilithia; Swann, Alan C; Dafny, Nachum

    2009-12-11

    Ingestion of 3, 4-methylenedioxymethamphetamine (MDMA) leads to heightened response to sensory stimulation; thus, MDMA is referred to as "ecstasy" because it produces pleasurable enhancement of such sensation. There have been no electrophysiological studies that report the consequences of MDMA on sensory input. The present study was initiated to study the effects of acute and chronic MDMA on locomotor activity and sensory evoked field potential from freely behaving rats previously implanted with permanent electrodes in the prefrontal cortex (PFC). The main findings of this study are that: (1) acute MDMA augments locomotor behavior and attenuates the incoming sensory input, (2) chronic treatment of MDMA elicits behavioral sensitization, (3) chronic administration of MDMA results in attenuation of the baseline activity of the sensory evoked field potential, and (4) administration of rechallenge MDMA result in enhancement of the PFC sensory evoked field potential. PMID:19769950

  16. Crystallinity Modulation of Layered Carbon Nitride for Enhanced Photocatalytic Activities.

    PubMed

    Wang, Jianhai; Shen, Yanfei; Li, Ying; Liu, Songqin; Zhang, Yuanjian

    2016-08-22

    As an emerging metal-free semiconductor, covalently bonded carbon nitride (CN) has attracted much attention in photocatalysis. However, drawbacks such as a high recombination rate of excited electrons and holes hinder its potential applications. Tailoring the crystallinity of semiconductors is an important way to suppress unwanted charge recombination, but has rarely been applied to CN so far. Herein, a simple method to synthesize CN of high crystallinity by protonation of specific intermediate species during conventional polymerization is reported. Interestingly, the as-obtained CN exhibited improved photocatalytic activities of up to seven times those of the conventional bulk CN. This approach, with only a slight change to the conventional method, provides a facile way to effectively regulate the crystallinity of bulk CN to improve its photocatalytic activities and sheds light on large-scale industrial applications of CN with high efficiency for sustainable energy. PMID:27436164

  17. Design, synthesis and bioactivity of novel phthalimide derivatives as acetylcholinesterase inhibitors.

    PubMed

    Si, Weijie; Zhang, Tao; Zhang, Lanxiang; Mei, Xiangdong; Dong, Mengya; Zhang, Kaixin; Ning, Jun

    2016-05-01

    A series of novel phthalimide derivatives related to benzylpiperazine were synthesized and evaluated as cholinesterase inhibitors. The results showed that all compounds were able to inhibit acetylcholinesterase (AChE), with two of them dramatically inhibiting butyrylcholinesterase (BuChE). Most compounds exhibited potent anti-AChE activity in the range of nM concentrations. In particular, compounds 7aIII and 10a showed the most potent activity with the IC50 values of 18.44nM and 13.58nM, respectively. To understand the excellent activity of these compounds, the structure-activity relationship was further examined. The protein-ligand docking study demonstrated that the target compounds have special binding modes and these results are in agreement with the kinetic study. PMID:27017111

  18. Synthesis, Biological Evaluation and Molecular Modelling of 2'-Hydroxychalcones as Acetylcholinesterase Inhibitors.

    PubMed

    Sukumaran, Sri Devi; Chee, Chin Fei; Viswanathan, Geetha; Buckle, Michael J C; Othman, Rozana; Abd Rahman, Noorsaadah; Chung, Lip Yong

    2016-01-01

    A series of 2'-hydroxy- and 2'-hydroxy-4',6'-dimethoxychalcones was synthesised and evaluated as inhibitors of human acetylcholinesterase (AChE). The majority of the compounds were found to show some activity, with the most active compounds having IC50 values of 40-85 µM. Higher activities were generally observed for compounds with methoxy substituents in the A ring and halogen substituents in the B ring. Kinetic studies on the most active compounds showed that they act as mixed-type inhibitors, in agreement with the results of molecular modelling studies, which suggested that they interact with residues in the peripheral anionic site and the gorge region of AChE. PMID:27455222

  19. Study of the interaction of Huperzia saururus Lycopodium alkaloids with the acetylcholinesterase enzyme.

    PubMed

    Puiatti, Marcelo; Borioni, José Luis; Vallejo, Mariana Guadalupe; Cabrera, José Luis; Agnese, Alicia Mariel; Ortega, María Gabriela; Pierini, Adriana Beatríz

    2013-07-01

    In the present study, we describe and compare the binding modes of three Lycopodium alkaloids (sauroine, 6-hydroxylycopodine and sauroxine; isolated from Huperzia saururus) and huperzine A with the enzyme acetylcholinesterase. Refinement and rescoring of the docking poses (obtained with different programs) with an all atom force field helped to improve the quality of the protein-ligand complexes. Molecular dynamics simulations were performed to investigate the complexes and the alkaloid's binding modes. The combination of the latter two methodologies indicated that binding in the active site is favored for the active compounds. On the other hand, similar binding energies in both the active and the peripheral sites were obtained for sauroine, thus explaining its experimentally determined lack of activity. MM-GBSA predicted the order of binding energies in agreement with the experimental IC50 values. PMID:23827878

  20. An Essential Viral Transcription Activator Modulates Chromatin Dynamics

    PubMed Central

    Gibeault, Rebecca L.; Bildersheim, Michael D.

    2016-01-01

    Although ICP4 is the only essential transcription activator of herpes simplex virus 1 (HSV-1), its mechanisms of action are still only partially understood. We and others propose a model in which HSV-1 genomes are chromatinized as a cellular defense to inhibit HSV-1 transcription. To counteract silencing, HSV-1 would have evolved proteins that prevent or destabilize chromatinization to activate transcription. These proteins should act as HSV-1 transcription activators. We have shown that HSV-1 genomes are organized in highly dynamic nucleosomes and that histone dynamics increase in cells infected with wild type HSV-1. We now show that whereas HSV-1 mutants encoding no functional ICP0 or VP16 partially enhanced histone dynamics, mutants encoding no functional ICP4 did so only minimally. Transient expression of ICP4 was sufficient to enhance histone dynamics in the absence of other HSV-1 proteins or HSV-1 DNA. The dynamics of H3.1 were increased in cells expressing ICP4 to a greater extent than those of H3.3. The dynamics of H2B were increased in cells expressing ICP4, whereas those of canonical H2A were not. ICP4 preferentially targets silencing H3.1 and may also target the silencing H2A variants. In infected cells, histone dynamics were increased in the viral replication compartments, where ICP4 localizes. These results suggest a mechanism whereby ICP4 activates transcription by disrupting, or preventing the formation of, stable silencing nucleosomes on HSV-1 genomes. PMID:27575707

  1. Detection and characterisation of delamination in PV modules by active infrared thermography

    NASA Astrophysics Data System (ADS)

    Sinha, A.; Sastry, O. S.; Gupta, R.

    2016-01-01

    The paper presents a fast and efficient method for the detection and characterisation of delamination in photovoltaic (PV) modules by using active infrared thermography approach. A discrete part of PV module was irradiated by step heating and its thermal image sequence was used to detect and analyse delamination. Different types of heating source for thermal excitation for this application have been studied. An electro-thermal model was developed to simulate the active thermography approach for the characterisation of delamination in PV module by equivalent resistance-capacitance (RC) network using a circuit simulator. This simulation approach was used to estimate the extent of delamination in the module and to determine the optimum parameters for the characterisation of delamination. Different applications based on front and backsides of heating the module were also proposed in this paper. The proposed method has the potential to be employed for the quality check of PV modules during inline production as well as for the predictive maintenance of outdoor PV plants.

  2. Allatotropin Modulates Myostimulatory and Cardioacceleratory Activities in Rhodnius prolixus (Stal).

    PubMed Central

    Villalobos-Sambucaro, María José; Lorenzo-Figueiras, Alicia Nieves; Riccillo, Fernando Luis; Diambra, Luis Anibal; Noriega, Fernando Gabriel; Ronderos, Jorge Rafael

    2015-01-01

    Haematophagous insects can ingest large quantities of blood in a single meal and eliminate high volumes of urine in the next few hours. This rise in diuresis is possible because the excretory activity of the Malpighian tubules is facilitated by an increase in haemolymph circulation as a result of intensification of aorta contractions combined with an increase of the anterior midgut peristaltic waves. It has been previously described that haemolymph circulation during post-prandial diuresis is stimulated by the synergistic activity of allatotropin (AT) and serotonin in the kissing bug Triatoma infestans; resulting in an increase in aorta contractions. In the same species, AT stimulates anterior midgut and rectum muscle contractions to mix urine and feces and facilitate the voiding of the rectum. Furthermore, levels of AT in midgut and Malpighian tubules increased in the afternoon when insects are getting ready for nocturnal feeding. In the present study we describe the synergistic effect of AT and serotonin increasing the frequency of contractions of the aorta in Rhodnius prolixus. The basal frequency of contractions of the aorta in the afternoon is higher that the observed during the morning, suggesting the existence of a daily rhythmic activity. The AT receptor is expressed in the rectum, midgut and dorsal vessel, three critical organs involved in post-prandial diuresis. All together these findings provide evidence that AT plays a role as a myoregulatory and cardioacceleratory peptide in R. prolixus. PMID:25897783

  3. PPARγ Activation Attenuates Opioid Consumption and Modulates Mesolimbic Dopamine Transmission

    PubMed Central

    de Guglielmo, Giordano; Melis, Miriam; De Luca, Maria Antonietta; Kallupi, Marsida; Li, Hong Wu; Niswender, Kevin; Giordano, Antonio; Senzacqua, Martina; Somaini, Lorenzo; Cippitelli, Andrea; Gaitanaris, George; Demopulos, Gregory; Damadzic, Ruslan; Tapocik, Jenica; Heilig, Markus; Ciccocioppo, Roberto

    2015-01-01

    PPARγ is one of the three isoforms identified for the peroxisome proliferator-activated receptors (PPARs) and is the receptor for the thiazolidinedione class of anti-diabetic medications including pioglitazone. PPARγ has been long studied for its role in adipogenesis and glucose metabolism, but the discovery of the localization in ventral tegmental area (VTA) neurons opens new vistas for a potential role in the regulation of reward processing and motivated behavior in drug addiction. Here, we demonstrate that activation of PPARγ by pioglitazone reduces the motivation for heroin and attenuates its rewarding properties. These effects are associated with a marked reduction of heroin-induced increase in phosphorylation of DARPP-32 protein in the nucleus accumbens (NAc) and with a marked and selective reduction of acute heroin-induced elevation of extracellular dopamine (DA) levels in the NAc shell, as measured by in vivo microdialysis. Through ex vivo electrophysiology in acute midbrain slices, we also show that stimulation of PPARγ attenuates opioid-induced excitation of VTA DA neurons via reduction of presynaptic GABA release from the rostromedial tegmental nucleus (RMTg). Consistent with this finding, site-specific microinjection of pioglitazone into the RMTg but not into the VTA reduced heroin taking. Our data illustrate that activation of PPARγ may represent a new pharmacotherapeutic option for the treatment of opioid addiction. PMID:25311134

  4. Lipid metabolizing enzyme activities modulated by phospholipid substrate lateral distribution.

    PubMed

    Salinas, Dino G; Reyes, Juan G; De la Fuente, Milton

    2011-09-01

    Biological membranes contain many domains enriched in phospholipid lipids and there is not yet clear explanation about how these domains can control the activity of phospholipid metabolizing enzymes. Here we used the surface dilution kinetic theory to derive general equations describing how complex substrate distributions affect the activity of enzymes following either the phospholipid binding kinetic model (which assumes that the enzyme molecules directly bind the phospholipid substrate molecules), or the surface-binding kinetic model (which assumes that the enzyme molecules bind to the membrane before binding the phospholipid substrate). Our results strongly suggest that, if the enzyme follows the phospholipid binding kinetic model, any substrate redistribution would increase the enzyme activity over than observed for a homogeneous distribution of substrate. Besides, enzymes following the surface-binding model would be independent of the substrate distribution. Given that the distribution of substrate in a population of micelles (each of them a lipid domain) should follow a Poisson law, we demonstrate that the general equations give an excellent fit to experimental data of lipases acting on micelles, providing reasonable values for kinetic parameters--without invoking special effects such as cooperative phenomena. Our theory will allow a better understanding of the cellular-metabolism control in membranes, as well as a more simple analysis of the mechanisms of membrane acting enzymes. PMID:21108012

  5. Implicitly perceived vocal attractiveness modulates prefrontal cortex activity.

    PubMed

    Bestelmeyer, Patricia E G; Latinus, Marianne; Bruckert, Laetitia; Rouger, Julien; Crabbe, Frances; Belin, Pascal

    2012-06-01

    Social interactions involve more than "just" language. As important is a more primitive nonlinguistic mode of communication acting in parallel with linguistic processes and driving our decisions to a much higher degree than is generally suspected. Amongst the "honest signals" that influence our behavior is perceived vocal attractiveness. Not only does vocal attractiveness reflect important biological characteristics of the speaker, it also influences our social perceptions according to the "what sounds beautiful is good" phenomenon. Despite the widespread influence of vocal attractiveness on social interactions revealed by behavioral studies, its neural underpinnings are yet unknown. We measured brain activity while participants listened to a series of vocal sounds ("ah") and performed an unrelated task. We found that voice-sensitive auditory and inferior frontal regions were strongly correlated with implicitly perceived vocal attractiveness. While the involvement of auditory areas reflected the processing of acoustic contributors to vocal attractiveness ("distance to mean" and spectrotemporal regularity), activity in inferior prefrontal regions (traditionally involved in speech processes) reflected the overall perceived attractiveness of the voices despite their lack of linguistic content. These results suggest the strong influence of hidden nonlinguistic aspects of communication signals on cerebral activity and provide an objective measure of this influence. PMID:21828348

  6. Allatotropin modulates myostimulatory and cardioacceleratory activities in Rhodnius prolixus (Stal).

    PubMed

    Villalobos-Sambucaro, María José; Lorenzo-Figueiras, Alicia Nieves; Riccillo, Fernando Luis; Diambra, Luis Anibal; Noriega, Fernando Gabriel; Ronderos, Jorge Rafael

    2015-01-01

    Haematophagous insects can ingest large quantities of blood in a single meal and eliminate high volumes of urine in the next few hours. This rise in diuresis is possible because the excretory activity of the Malpighian tubules is facilitated by an increase in haemolymph circulation as a result of intensification of aorta contractions combined with an increase of the anterior midgut peristaltic waves. It has been previously described that haemolymph circulation during post-prandial diuresis is stimulated by the synergistic activity of allatotropin (AT) and serotonin in the kissing bug Triatoma infestans; resulting in an increase in aorta contractions. In the same species, AT stimulates anterior midgut and rectum muscle contractions to mix urine and feces and facilitate the voiding of the rectum. Furthermore, levels of AT in midgut and Malpighian tubules increased in the afternoon when insects are getting ready for nocturnal feeding. In the present study we describe the synergistic effect of AT and serotonin increasing the frequency of contractions of the aorta in Rhodnius prolixus. The basal frequency of contractions of the aorta in the afternoon is higher that the observed during the morning, suggesting the existence of a daily rhythmic activity. The AT receptor is expressed in the rectum, midgut and dorsal vessel, three critical organs involved in post-prandial diuresis. All together these findings provide evidence that AT plays a role as a myoregulatory and cardioacceleratory peptide in R. prolixus. PMID:25897783

  7. Dopamine Transporter Activity Is Modulated by α-Synuclein.

    PubMed

    Butler, Brittany; Saha, Kaustuv; Rana, Tanu; Becker, Jonas P; Sambo, Danielle; Davari, Paran; Goodwin, J Shawn; Khoshbouei, Habibeh

    2015-12-01

    The duration and strength of the dopaminergic signal are regulated by the dopamine transporter (DAT). Drug addiction and neurodegenerative and neuropsychiatric diseases have all been associated with altered DAT activity. The membrane localization and the activity of DAT are regulated by a number of intracellular proteins. α-Synuclein, a protein partner of DAT, is implicated in neurodegenerative disease and drug addiction. Little is known about the regulatory mechanisms of the interaction between DAT and α-synuclein, the cellular location of this interaction, and the functional consequences of this interaction on the basal, amphetamine-induced DAT-mediated dopamine efflux, and membrane microdomain distribution of the transporter. Here, we found that the majority of DAT·α-synuclein protein complexes are found at the plasma membrane of dopaminergic neurons or mammalian cells and that the amphetamine-mediated increase in DAT activity enhances the association of these proteins at the plasma membrane. Further examination of the interaction of DAT and α-synuclein revealed a transient interaction between these two proteins at the plasma membrane. Additionally, we found DAT-induced membrane depolarization enhances plasma membrane localization of α-synuclein, which in turn increases dopamine efflux and enhances DAT localization in cholesterol-rich membrane microdomains. PMID:26442590

  8. Turbulent electromagnetic filaments in actively modulated toroidal plasma edge

    NASA Astrophysics Data System (ADS)

    Spolaore, M.; Agostini, M.; Momo, B.; Rea, C.; Vianello, N.; Zuin, M.; Cavazzana, R.; De Masi, G.; Innocente, P.; Marrelli, L.; Martines, E.; Mazzi, A.; Puiatti, M. E.; Spagnolo, S.; Spizzo, G.; Scarin, P.; Terranova, D.; Zanca, P.

    2015-06-01

    Filament or blob structures have been observed in all magnetic configurations with very similar features despite the difference in the magnetic geometry, and are believed to play an important role in convecting particles and energy towards the wall. Despite their different generation mechanism, turbulent structures and edge-localized mode (ELM) filaments share some common physical features. The electromagnetic effects on filament structures deserve particular interest, among others reasons for the implication they could have for ELM, related for instance to their dynamics in the transition region between closed and open field lines or to the possibility, at high beta regimes, of causing line bending which could enhance the interaction of blobs with the first wall. A direct characterization of the effects of active modification of the edge topology on EM turbulent filament structures is presented, comparing reversed field pinch and tokamak configurations. Measurements are obtained in the RFX-mod device, which allows operation in both configurations and with different equilibria. The RFX-mod experiment versatility is exploited also from the point of view of the active control of the edge magnetic topology, equipped with an advanced system for edge boundary feedback control. Three different case studies of actively controlled magnetic perturbations are shown, focusing on the filament interaction with local magnetic islands. High-frequency fluctuations, characterizing electrostatic and magnetic filament features, and the associated transport coefficients have been observed to be strongly affected by the island proximity and topology.

  9. Modulation of bone remodeling via mechanically activated ion channels

    NASA Technical Reports Server (NTRS)

    Duncan, Randall L. (Principal Investigator)

    1996-01-01

    A critical factor in the maintenance of bone mass is the physical forces imposed upon the skeleton. Removal of these forces, such as in a weightless environment, results in a rapid loss of bone, whereas application of exogenous mechanical strain has been shown to increase bone formation. Numerous flight and ground-based experiments indicate that the osteoblast is the key bone cell influenced by mechanical stimulation. Aside from early transient fluctuations in response to unloading, osteoclast number and activity seem unaffected by removal of strain. However, bone formation is drastically reduced in weightlessness and osteoblasts respond to mechanical strain with an increase in the activity of a number of second messenger pathways resulting in increased anabolic activity. Unfortunately, the mechanism by which the osteoblast converts physical stimuli into a biochemical message, a process we have termed biochemical coupling, remains elusive. Prior to the application of this grant, we had characterized a mechanosensitive, cation nonselective channel (SA-cat) in osteoblast-like osteosarcoma cells that we proposed is the initial signalling mechanism for mechanotransduction. During the execution of this grant, we have made considerable progress to further characterize this channel as well as to determine its role in the osteoblastic response to mechanical strain. To achieve these goals, we combined electrophysiologic techniques with cellular and molecular biology methods to examine the role of these channels in the normal function of the osteoblast in vitro.

  10. Multifractal detrended fluctuation analysis of optogenetic modulation of neural activity

    NASA Astrophysics Data System (ADS)

    Kumar, S.; Gu, L.; Ghosh, N.; Mohanty, S. K.

    2013-02-01

    Here, we introduce a computational procedure to examine whether optogenetically activated neuronal firing recordings could be characterized as multifractal series. Optogenetics is emerging as a valuable experimental tool and a promising approach for studying a variety of neurological disorders in animal models. The spiking patterns from cortical region of the brain of optogenetically-stimulated transgenic mice were analyzed using a sophisticated fluctuation analysis method known as multifractal detrended fluctuation analysis (MFDFA). We observed that the optogenetically-stimulated neural firings are consistent with a multifractal process. Further, we used MFDFA to monitor the effect of chemically induced pain (formalin injection) and optogenetic treatment used to relieve the pain. In this case, dramatic changes in parameters characterizing a multifractal series were observed. Both the generalized Hurst exponent and width of singularity spectrum effectively differentiates the neural activities during control and pain induction phases. The quantitative nature of the analysis equips us with better measures to quantify pain. Further, it provided a measure for effectiveness of the optogenetic stimulation in inhibiting pain. MFDFA-analysis of spiking data from other deep regions of the brain also turned out to be multifractal in nature, with subtle differences in the parameters during pain-induction by formalin injection and inhibition by optogenetic stimulation. Characterization of neuronal firing patterns using MFDFA will lead to better understanding of neuronal response to optogenetic activation and overall circuitry involved in the process.

  11. Modulating Photoluminescence of Monolayer Molybdenum Disulfide by Metal-Insulator Phase Transition in Active Substrates.

    PubMed

    Hou, Jiwei; Wang, Xi; Fu, Deyi; Ko, Changhyun; Chen, Yabin; Sun, Yufei; Lee, Sangwook; Wang, Kevin X; Dong, Kaichen; Sun, Yinghui; Tongay, Sefaattin; Jiao, Liying; Yao, Jie; Liu, Kai; Wu, Junqiao

    2016-08-01

    The atomic thickness and flatness allow properties of 2D semiconductors to be modulated with influence from the substrate. Reversible modulation of these properties requires an "active," reconfigurable substrate, i.e., a substrate with switchable functionalities that interacts strongly with the 2D overlayer. In this work, the photoluminescence (PL) of monolayer molybdenum disulfide (MoS2 ) is modulated by interfacing it with a phase transition material, vanadium dioxide (VO2 ). The MoS2 PL intensity is enhanced by a factor of up to three when the underlying VO2 undergoes the thermally driven phase transition from the insulating to metallic phase. A nonvolatile, reversible way to rewrite the PL pattern is also demonstrated. The enhancement effect is attributed to constructive optical interference when the VO2 turns metallic. This modulation method requires no chemical or mechanical processes, potentially finding applications in new switches and sensors. PMID:27335137

  12. Respiratory modulation of sympathetic nerve activity is enhanced in male rat offspring following uteroplacental insufficiency.

    PubMed

    Menuet, C; Wlodek, M E; Fong, A Y; Allen, A M

    2016-06-01

    Sympathetic nerve activity to the cardiovascular system displays prominent respiratory-related modulation which leads to the generation of rhythmic oscillations in blood pressure called Traube-Hering waves. An amplification of this respiratory modulation of sympathetic activity is observed in hypertension of both genetic, the spontaneously hypertensive rat, and induced, chronic intermittent hypoxia or maternal protein restriction during gestation, origin. Male offspring of mothers with uteroplacental insufficiency, induced by bilateral uterine vessel ligation at 18 days of gestation, are also hypertensive in adulthood. In this study we examined whether these male offspring display altered respiratory modulation of sympathetic activity at pre-hypertensive ages compared to controls. Respiratory, cardiovascular and sympathetic parameters were examined using the working heart-brainstem preparation in 35 day old male rats that had reduced birth weight due to uteroplacental insufficiency. Whilst all respiratory parameters were not different between groups, we observed an enhanced respiratory-related burst of thoracic sympathetic nerve activity and amplified Traube-Hering waves in the growth-restricted group. This group also showed an increased sympathetic and bradycardic response to activation of peripheral chemoreceptors. The observations add support to the view that altered respiratory modulation of sympathetic activity represents a common mechanism involved in the development of several forms of hypertension. PMID:26593642

  13. Reciprocal regulation of acetylcholinesterase and butyrylcholinesterase in mammalian skeletal muscle.

    PubMed

    Berman, H A; Decker, M M; Jo, S

    1987-03-01

    Developmental regulation, from the fetal period to 11 months of age, and the influence of denervation on the appearance and disappearance of the molecular forms of acetylcholinesterase (AchE) and butyrylcholinesterase (BuchE) in rat skeletal muscle were examined. The enzyme forms were extracted from anterior tibialis in 0.01 M sodium phosphate buffer, pH 7.0, containing 1 N NaCl, 0.01 M EGTA, 1% Triton X-100, and a cocktail of antiproteases, and analyzed by velocity sedimentation on 5-20% linear sucrose gradients. Three principal forms, denoted by sedimentation coefficients of 4, 10.8, and 16 S, were observed in muscle from all age groups. The amounts of each of the molecular forms of AchE and BuchE in skeletal muscle exhibited distinct and reciprocal patterns of appearance and disappearance during pre- and postnatal development. In tissue derived from animals less than 2 weeks of age, BuchE represented the predominant component of activity in the 4 S form, was present equally with AchE in the 10.8 S form, and was subordinate to AchE in the 16 S form. Between 1 and 2 weeks of age a progressive increase in AchE activities coincident with a reduction in BuchE activities resulted in inversion in the amounts of the two enzymes present in adult muscle. Denervation of muscle caused a dramatic reduction in the presence of AchE molecular forms with no discernable influence on the presence of BuchE molecular forms. These results indicate that biosynthesis of BuchE is strictly regulated in a reciprocal manner with that of AchE, and that BuchE metabolism is independent of the state of muscle innervation. Increased synthesis of AchE and either reduced synthesis or increased degradation of BuchE can account for the reciprocal regulation of these enzymes. These characteristics of mammalian muscle contrast sharply with characteristics deduced for avian tissue (Silman et al. (1979) Nature (London) 280, 160-162). The innervation-independent metabolism of BuchE and the diverse modes

  14. Activation of the Endoperoxide Ascaridole Modulates Its Sensitizing Capacity.

    PubMed

    Krutz, Nora L; Hennen, Jennifer; Korb, Corinna; Schellenberger, Mario T; Gerberick, G Frank; Blömeke, Brunhilde

    2015-10-01

    The monoterpene ascaridole, a fairly stable endoperoxide found in essential oils such as tea tree oil can provoke allergic contact dermatitis which has been evidenced under patch test conditions. However, concomitantly we observed irritative skin reactions that demand further data underlining the sensitization potential of ascaridole. Here, we studied the effects of ascaridole on dendritic cell (DC) activation and protein reactivity, 2 key steps of chemical-induced skin sensitization. Treatment of human monocyte-derived DC with ascaridole found support for full DC maturation, a capability of sensitizers but not irritants. It induced significant upregulation of the expression of the costimulatory molecules CD86, CD80, CD40, and the adhesion molecule CD54 in a time-dependent manner. Maturation was accompanied by release of proinflammatory cytokines interleukin (IL)-1ß, tumor necrosis factor-α, IL-6, and IL-8. Similar to other chemical skin sensitizers including hydroperoxides, we observed a certain reactivity of ascaridole toward cysteine- but not lysine-containing peptides. During recent years, evidence accumulated for a radical mechanism as trigger for protein reactivity of peroxides. Treatment of the fairly stable endoperoxide ascaridole with iron as radical inducer ("activated ascaridole") resulted in cysteine peptide reactivity exceeding by far that of ascaridole itself. Furthermore, activated ascaridole showed increased potential for induction of the Nrf2 target gene heme oxygenase 1 and upregulation of CD86 and CD54 on THP-1 cells, an established DC surrogate. These results indicate that radical formation could be involved in the steps leading to skin sensitization induced by the endoperoxide ascaridole. PMID:26185204

  15. Surface Display and Bioactivity of Bombyx mori Acetylcholinesterase on Pichia pastoris

    PubMed Central

    He, Yong-Sheng; Beier, Ross C.; Sun, Yuan-Ming; Xu, Zhen-Lin; Wu, Wei-Jian; Shen, Yu-Dong; Xiao, Zhi-Li; Lai, Li-Na; Wang, Hong; Yang, Jin-Yi

    2013-01-01

    A Pichia pastoris (P. pastoris) cell surface display system of Bombyx mori acetylcholinesterase (BmAChE) was constructed and its bioactivity was studied. The modified Bombyx mori acetylcholinesterase gene (bmace) was fused with the anchor protein (AGα1) from Saccharomyces cerevisiae and transformed into P. pastoris strain GS115. The recombinant strain harboring the fusion gene bmace-AGα1 was induced to display BmAChE on the P. pastoris cell surface. Fluorescence microscopy and flow cytometry assays revealed that the BmAChE was successfully displayed on the cell surface of P. pastoris GS115. The enzyme activity of the displayed BmAChE was detected by the Ellman method at 787.7 U/g (wet cell weight). In addition, bioactivity of the displayed BmAChE was verified by inhibition tests conducted with eserine, and with carbamate and organophosphorus pesticides. The displayed BmAChE had an IC50 of 4.17×10−8 M and was highly sensitive to eserine and five carbamate pesticides, as well as seven organophosphorus pesticides. Results suggest that the displayed BmAChE had good bioactivity. PMID:23940577

  16. Novel and Viable Acetylcholinesterase Target Site for Developing Effective and Environmentally Safe Insecticides

    PubMed Central

    Pang, Yuan-Ping; Brimijoin, Stephen; Ragsdale, David W; Zhu, Kun Yan; Suranyi, Robert

    2012-01-01

    Insect pests are responsible for human suffering and financial losses worldwide. New and environmentally safe insecticides are urgently needed to cope with these serious problems. Resistance to current insecticides has resulted in a resurgence of insect pests, and growing concerns about insecticide toxicity to humans discourage the use of insecticides for pest control. The small market for insecticides has hampered insecticide development; however, advances in genomics and structural genomics offer new opportunities to develop insecticides that are less dependent on the insecticide market. This review summarizes the literature data that support the hypothesis that an insect-specific cysteine residue located at the opening of the acetylcholinesterase active site is a promising target site for developing new insecticides with reduced off-target toxicity and low propensity for insect resistance. These data are used to discuss the differences between targeting the insect-specific cysteine residue and targeting the ubiquitous catalytic serine residue of acetylcholinesterase from the perspective of reducing off-target toxicity and insect resistance. Also discussed is the prospect of developing cysteine-targeting anticholinesterases as effective and environmentally safe insecticides for control of disease vectors, crop damage, and residential insect pests within the financial confines of the present insecticide market. PMID:22280344

  17. Control of Foxp3 stability through modulation of TET activity.

    PubMed

    Yue, Xiaojing; Trifari, Sara; Äijö, Tarmo; Tsagaratou, Ageliki; Pastor, William A; Zepeda-Martínez, Jorge A; Lio, Chan-Wang J; Li, Xiang; Huang, Yun; Vijayanand, Pandurangan; Lähdesmäki, Harri; Rao, Anjana

    2016-03-01

    Ten-eleven translocation (TET) enzymes oxidize 5-methylcytosine (5mC) to 5-hydroxymethylcytosine and other oxidized methylcytosines, intermediates in DNA demethylation. In this study, we examine the role of TET proteins in regulating Foxp3, a transcription factor essential for the development and function of regulatory T cells (T reg cells), a distinct lineage of CD4(+) T cells that prevent autoimmunity and maintain immune homeostasis. We show that during T reg cell development in the thymus, TET proteins mediate the loss of 5mC in T reg cell-specific hypomethylated regions, including CNS1 and CNS2, intronic cis-regulatory elements in the Foxp3 locus. Similar to CNS2-deficient T reg cells, the stability of Foxp3 expression is markedly compromised in T reg cells from Tet2/Tet3 double-deficient mice. Vitamin C potentiates TET activity and acts through Tet2/Tet3 to increase the stability of Foxp3 expression in TGF-β-induced T reg cells. Our data suggest that targeting TET enzymes with small molecule activators such as vitamin C might increase induced T reg cell efficacy. PMID:26903244

  18. Control of Foxp3 stability through modulation of TET activity

    PubMed Central

    Yue, Xiaojing; Trifari, Sara; Äijö, Tarmo; Tsagaratou, Ageliki; Pastor, William A.; Zepeda-Martínez, Jorge A.; Lio, Chan-Wang J.; Li, Xiang; Huang, Yun; Vijayanand, Pandurangan; Lähdesmäki, Harri

    2016-01-01

    Ten-eleven translocation (TET) enzymes oxidize 5-methylcytosine (5mC) to 5-hydroxymethylcytosine and other oxidized methylcytosines, intermediates in DNA demethylation. In this study, we examine the role of TET proteins in regulating Foxp3, a transcription factor essential for the development and function of regulatory T cells (T reg cells), a distinct lineage of CD4+ T cells that prevent autoimmunity and maintain immune homeostasis. We show that during T reg cell development in the thymus, TET proteins mediate the loss of 5mC in T reg cell–specific hypomethylated regions, including CNS1 and CNS2, intronic cis-regulatory elements in the Foxp3 locus. Similar to CNS2-deficient T reg cells, the stability of Foxp3 expression is markedly compromised in T reg cells from Tet2/Tet3 double-deficient mice. Vitamin C potentiates TET activity and acts through Tet2/Tet3 to increase the stability of Foxp3 expression in TGF-β–induced T reg cells. Our data suggest that targeting TET enzymes with small molecule activators such as vitamin C might increase induced T reg cell efficacy. PMID:26903244

  19. OASIS modulates hypoxia pathway activity to regulate bone angiogenesis

    PubMed Central

    Cui, Min; Kanemoto, Soshi; Cui, Xiang; Kaneko, Masayuki; Asada, Rie; Matsuhisa, Koji; Tanimoto, Keiji; Yoshimoto, Yuki; Shukunami, Chisa; Imaizumi, Kazunori

    2015-01-01

    OASIS/CREB3L1, an endoplasmic reticulum (ER)-resident transcription factor, plays important roles in osteoblast differentiation. In this study, we identified new crosstalk between OASIS and the hypoxia signaling pathway, which regulates vascularization during bone development. RT-PCR and real-time PCR analyses revealed significant decreases in the expression levels of hypoxia-inducible factor-1α (HIF-1α) target genes such as vascular endothelial growth factor A (VEGFA) in OASIS-deficient (Oasis−/−) mouse embryonic fibroblasts. In coimmunoprecipitation experiments, the N-terminal fragment of OASIS (OASIS-N; activated form of OASIS) bound to HIF-1α through the bZIP domain. Luciferase assays showed that OASIS-N promoted the transcription activities of a reporter gene via a hypoxia-response element (HRE). Furthermore, the expression levels of an angiogenic factor Vegfa was decreased in Oasis−/− osteoblasts. Immunostaining and metatarsal angiogenesis assay showed retarded vascularization in bone tissue of Oasis−/− mice. These results suggest that OASIS affects the expression of HIF-1α target genes through the protein interaction with HIF-1α, and that OASIS-HIF-1α complexes may play essential roles in angiogenesis during bone development. PMID:26558437

  20. The Wnt receptor Frizzled-4 modulates ADAM13 metalloprotease activity

    PubMed Central

    Abbruzzese, Genevieve; Gorny, Anne-Kathrin; Kaufmann, Lilian T.; Cousin, Hélène; Kleino, Iivari; Steinbeisser, Herbert; Alfandari, Dominique

    2015-01-01

    ABSTRACT Cranial neural crest (CNC) cells are a transient population of stem cells that originate at the border of the neural plate and the epidermis, and migrate ventrally to contribute to most of the facial structures including bones, cartilage, muscles and ganglia. ADAM13 is a cell surface metalloprotease that is essential for CNC cell migration. Here, we show in Xenopus laevis embryos that the Wnt receptor Fz4 binds to the cysteine-rich domain of ADAM13 and negatively regulates its proteolytic activity in vivo. Gain of Fz4 function inhibits CNC cell migration and can be rescued by gain of ADAM13 function. Loss of Fz4 function also inhibits CNC cell migration and induces a reduction of mature ADAM13, together with an increase in the ADAM13 cytoplasmic fragment that is known to translocate into the nucleus to regulate gene expression. We propose that Fz4 associates with ADAM13 during its transport to the plasma membrane to regulate its proteolytic activity. PMID:25616895

  1. VISUAL ELEMENTS OF SUBJECTIVE PREFERENCE MODULATE AMYGDALA ACTIVATION

    PubMed Central

    Bar, Moshe; Neta, Maital

    2010-01-01

    What are the basic visual cues that determine our preference towards mundane everyday objects? We previously showed that a highly potent cue is the nature of the object’s contour: people generally like objects with a curved contour compared with objects that have pointed features and a sharp-angled contour. This bias is hypothesized here to stem from an implicit perception of potential threat conveyed by sharp elements. Using human neuroimaging to test this hypothesis, we report that the amygdala, a brain structure that is involved in fear processing and has been shown to exhibit activation level that is proportional to arousal in general, is significantly more active for everyday sharp objects (e.g., a sofa with sharp corners) compared with their curved-contour counterparts. Therefore, our results indicate that a preference bias towards a visual object can be induced by low-level perceptual properties, independent of semantic meaning, via visual elements that on some level could be associated with threat. We further present behavioral results that provide initial support for the link between the sharpness of the contour and threat perception. Our brains might be organized to extract these basic contour elements rapidly for deriving an early warning signal in the presence of potential danger. PMID:17462678

  2. The Geography of Greenhouse Gas Emissions: Hands-On! Developing Active Learning Modules on the Human Dimensions of Global Change.

    ERIC Educational Resources Information Center

    Liverman, Diana; Solem, Michael

    This learning module aims to engage students in problem solving, critical thinking, scientific inquiry, and cooperative learning. The module is appropriate for use in any introductory or intermediate undergraduate course that focuses on human-environment relationships. The module examines the geography of human activities that produce the major…

  3. Mutation at codon 322 in the human acetylcholinesterase (ACHE) gene accounts for YT blood group polymorphism

    SciTech Connect

    Bartels, C.F.; Lockridge, O. ); Zelinski, T. )

    1993-05-01

    Acetylcholinesterase is present in innervated tissues, where its function is to terminate nerve impulse transmission. It is also found in the red blood cell membrane, where its function is unknown. The authors report the first genetic variant of human acetylcholinesterase and support the identity of acetylcholinesterase as the YT blood group antigen. DNA sequencing shows that the wild-type sequence of acetylcholinesterase with His322 (CAC) is the YT1 blood group antigen and that the rare variant of acetylcholinesterase with Asn322 (AAC) is the YT2 blood group antigen. Two additional point mutations in the acetylcholinesterase gene do not affect the amino acid sequence of the mature enzyme. 41 refs., 6 figs., 1 tab.

  4. Modulation of P-glycoprotein ATPase activity by some phytoconstituents.

    PubMed

    Najar, I A; Sachin, B S; Sharma, S C; Satti, N K; Suri, K A; Johr