scholarly journals Kinetic Evaluation of the Inhibition of Acetylcholinesterase for use as a biosensor

2020 ◽  
Vol 20 (1) ◽  
pp. 99
Author(s):  
R. Bhuvanagayathri ◽  
David K Daniel ◽  
Gnanasundaram Nirmala
Keyword(s):  
Kinetic Parameter ◽  
Mixed Type ◽  
Acetylcholinesterase Activity ◽  
Reaction Rates ◽  
Acetylcholinesterase Inhibition ◽  
Inhibition Rate ◽  
Sensing Element ◽  
Kinetic Evaluation ◽  
Factors Affecting ◽  
Inhibition Rate Constant

The release of pesticides into the environment has increased, and there is a lack of monitoring of these contaminants. Since the conventional methods of monitoring these contaminants are complicated, costly and time-consuming, mechanisms based on acetylcholinesterase inhibition have emerged as simple and rapid tools for such applications. However, theacetylcholinesterase’s effectiveness as a sensing element in such biosensor systems depend­s on the conditions selected to measure acetylcholinesterase activity and the concentration of substrate or inhibitor, which in turn affect the reaction rates. Therefore, in the present work, the factors affecting the acetylcholinesterase activity were investigated and inhibition experiments were carried out to evaluate the kinetic parameters. The inhibition rate constant for acetylcholinesterase Ki was found to be 1.9 ppm. The kinetic parameter Km was found to be 3.8mM and Vmax was found to be 1.3µM/min from the Eadie-Hofstee plot. The kinetic study using Lineweaver-Burk method showed mixed type of inhibition of acetylcholinesterase with carbofuran.

scholarly journals Synthesis, Biological Evaluation and Docking Studies of Chalcone and Flavone Analogs as Antioxidants and Acetylcholinesterase Inhibitors

2019 ◽  
Vol 9 (3) ◽  
pp. 410 ◽  
Author(s):  
Laura Díaz-Rubio ◽  
Rufina Hernández-Martínez ◽  
Arturo Estolano-Cobián ◽  
Daniel Chávez-Velasco ◽  
Ricardo Salazar-Aranda ◽  
...  
Keyword(s):  
Acetylcholinesterase Inhibitors ◽  
Acetylcholinesterase Activity ◽  
Biological Evaluation ◽  
Chemotherapeutic Agents ◽  
Acetylcholinesterase Inhibition ◽  
Ache Inhibitors ◽  
Antioxidant Agents ◽  
Wide Range ◽  
Β Carotene

Several oxidative processes are related to a wide range of human chronic and degenerative diseases, like Alzheimer’s disease, which also has been related to cholinergic processes. Therefore, search for new or improved antioxidant molecules with acetylcholinesterase activity is essential to offer alternative chemotherapeutic agents to support current drug therapies. A series of chalcone (2a–2k) and flavone (3a–3k) analogs were synthesized, characterized, and evaluated as acetylcholinesterase (AChE) inhibitors, and antioxidant agents using 1,1-diphenyl-2-picrylhydrazyl (DPPH•), 2-2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS•), and β-carotene/linoleic acid bleaching assay. Compounds more active were 3j and 2k in DPPH with EC50 of 1 × 10−8 and 5.4 × 10−3 μg/mL, respectively; 2g and 3i in ABTS (1.14 × 10−2 and 1.9 × 10−3 μg/mL); 2e, 2f, 3f, 2j, and 3j exceeded the α-tocopherol control in the β-carotene assay (98–99% of antioxidant activity). At acetylcholinesterase inhibition assay, flavones were more active than chalcones; the best results were compounds 2d and 3d (IC50 21.5 and 26.8 µg/mL, respectively), suggesting that the presence of the nitro group enhances the inhibitory activity. The docking of these two structures were made to understand their interactions with the AChE receptor. Although further in vivo testing must be performed, our results represent an important step towards the identification of improved antioxidants and acetylcholinesterase inhibitors.

Factors affecting potassium release in calcareous soils of southern Iran

Soil Research ◽  
2011 ◽  
Vol 49 (6) ◽  
pp. 529 ◽  
Author(s):  
Mahdi Najafi Ghiri ◽  
Ali Abtahi ◽  
Fatemeh Jaberian
Keyword(s):  
Release Rate ◽  
Soil Depth ◽  
Release Kinetics ◽  
Calcareous Soils ◽  
Reaction Rates ◽  
Climatic Conditions ◽  
Factors Affecting ◽  
Southern Iran ◽  
K Release Rate ◽  
K Release

Experiments were conducted on 48 representative surface and subsurface soils collected from different climatic and physiographic conditions in southern Iran to assess factors affecting potassium (K) release and to find the best fitting models to describe the release kinetics of K to 0.01 m CaCl2. Mineralogical analysis showed that smectite, mica, chlorite, and palygorskite were the main clay minerals in the studied soils, whereas quartz, mica, and feldspars were abundant in the silt and sand fractions. Results indicated that cumulative K released ranged from 26.7 to 260 mg/kg (mean 176 mg/kg) for surface soils and from 37.9 to 198 mg/kg (mean 130 mg/kg) for subsurface soils. The predominant source of K in the soils appeared to be mica, because there was a significant relationship between cumulative K released and mica content. The percentage of non-exchangeable K release to CaCl2 during 1496 h was also correlated with the ratio of mica in the coarse fractions to total mica in the whole soil. Results showed that the Elovich equation adequately described the reaction rates of K release from surface and subsurface soils and suggested a heterogeneous diffusion process. We concluded that mica content and its particle size, soil depth, and some soil properties are the main factors controlling K release rate. On the other hand, we found no significant relationships between K release rate and climatic conditions, or physiographic positions.

An acetylcholinesterase inhibitor, donepezil, increases anxiety and cortisol levels in adult zebrafish

2020 ◽  
Vol 34 (12) ◽  
pp. 1449-1456 ◽  
Author(s):  
Ana CVV Giacomini ◽  
Barbara W Bueno ◽  
Leticia Marcon ◽  
Naiara Scolari ◽  
Rafael Genario ◽  
...  
Keyword(s):  
Acetylcholinesterase Inhibitor ◽  
Model Organism ◽  
Acetylcholinesterase Activity ◽  
Acetylcholinesterase Inhibition ◽  
Whole Body ◽  
The Novel ◽  
Adult Zebrafish ◽  
Tank Test ◽  
Cortisol Levels ◽  
Brain Acetylcholinesterase

Background: A potent acetylcholinesterase inhibitor, donepezil is a cognitive enhancer clinically used to treat neurodegenerative diseases. However, its complete pharmacological profile beyond cognition remains unclear. The zebrafish ( Danio rerio) is rapidly becoming a powerful novel model organism in neuroscience and central nervous system drug screening. Aim: Here, we characterize the effects of 24-h donepezil administration on anxiety-like behavioral and endocrine responses in adult zebrafish. Methods: We evaluated zebrafish anxiety-like behaviors in the novel tank, the light-dark and the shoaling tests, paralleled by assessing brain acetylcholinesterase activity and whole-body cortisol levels. Results: Overall, donepezil dose-dependently decreased zebrafish locomotor activity in the novel tank test and reduced time in light in the light-dark test, likely representing hypolocomotion and anxiety-like behaviors. Donepezil predictably decreased brain acetylcholinesterase activity, also increasing whole-body cortisol levels, thus further linking acetylcholinesterase inhibition to anxiety-like behavioral and endocrine responses. Conclusion: Collectively, these findings suggest negative modulation of zebrafish affective behavior by donepezil, support the key role of cholinergic mechanisms in behavioral regulation in zebrafish, and reinforce the growing utility of zebrafish models for studying complex behavioral processess and their neuroendocrine and neurochemical regulation.

scholarly journals AN α-PARTICLE AUTORADIOGRAPHIC METHOD FOR QUANTIFYING THE INHIBITION OF ACETYLCHOLINESTERASE AT THE MYONEURAL JUNCTION

1969 ◽  
Vol 17 (4) ◽  
pp. 244-248 ◽  
Author(s):  
ROBERT R. LANDOLT ◽  
PAUL L. ZIEMER ◽  
JOHN E. CHRISTIAN
Keyword(s):  
Production Rate ◽  
Acetylcholinesterase Activity ◽  
Acetylcholinesterase Inhibition ◽  
Myoneural Junction ◽  
Inhibition Study ◽  
Tissue Sections ◽  
Autoradiographic Method ◽  
Irreversible Inhibitors ◽  
Sigmoidal Curve ◽  
Α Particles

An existing histochemical method was adapted to α-particle autoradiography to provide a means of quantifying acetylcholinesterase inhibition at myoneural junctions. The α-particles were emitted from polonium 210 which was present in the precipitate after staining. A technique was designed for counting areas of dense α-particle tracks on the autoradiograms which corresponded to sites of acetylcholinesterase activity. An experiment was performed which showed that the track production rate was consistent for several diaphragm sections when incubated under identical conditions with no inhibitor. Tissue sections of this type, representing zero inhibition, were used as controls for inhibitor studies. It was also demonstrated that the track production rate was constant during the different exposure times used in the inhibition study. Diisopropylfluorophosphate was used to evaluate the autoradiographic method of quantifying acetylcholinesterase inhibition. A plot of log inhibitor concentration against percentage inhibition resulted in a smooth sigmoidal curve which is typical of irreversible inhibitors.

Mercury photochemistry in snow and implications for Arctic ecosystems

2014 ◽  
Vol 22 (4) ◽  
pp. 331-345 ◽  
Author(s):  
Erin Mann ◽  
Susan Ziegler ◽  
Mark Mallory ◽  
Nelson O’Driscoll
Keyword(s):  
Surface Water ◽  
Photochemical Reaction ◽  
Aquatic Organisms ◽  
Reaction Rates ◽  
The Arctic ◽  
Arctic Ecosystems ◽  
Factors Affecting ◽  
The World ◽  
Physical And Chemical ◽  
Receiving Water

Mercury is a toxic and bioaccumulative environmental contaminant, which may be transported to remote regions around the world, such as the Arctic. Snowmelt is a major source of mercury to many surface water environments, but the amount of mercury in snow varies considerably. This variation is due to the balance of mercury retention and losses from snow, which is largely controlled by photochemical mechanisms controlling speciation. As such, quantifying these photochemical reaction rates and the factors affecting them will allow for the prediction of mercury speciation and movement into receiving water bodies. This will consequently improve our ability to predict exposure of aquatic organisms to mercury. This review highlights knowledge gaps in the quantification of mercury photochemical kinetics and the specific research required to advance the science of mercury photochemistry in snow, while examining the physical and chemical snowpack variables that influence snowpack mercury reactions. At present, our lack of mechanistic and kinetic knowledge of mercury reactions in snow is one of the greatest gaps preventing accurate predictions of mercury fate in regions containing seasonal snowpacks.

Study on Corrosion Inhibitor Technology in Gas Pipeline

2011 ◽  
Vol 317-319 ◽  
pp. 2007-2012 ◽  
Author(s):  
Yun Ping Zheng ◽  
Cheng Qiang Ren ◽  
Shao Ping Ai ◽  
Feng Zhang ◽  
Jiang Shan
Keyword(s):  
Mixed Type ◽  
Gas Pipeline ◽  
Inhibition Rate ◽  
Gas Field ◽  
Corrosion Failure ◽  
Corrosion Medium ◽  
Development Technology ◽  
Oil And Natural Gas ◽  
Corrosion Problem ◽  
Mixed Type Inhibitor

With the advance of the exploration and development technology, the corrosion problem in oil and natural gas industries has attracted more and more attention due to the appearance of H2S, CO2 and other corrosion medium in the oilfields. 20G steel was used as materials of the gas pipeline in P5 gas field. Corrosion failure of the gathering pipeline of No. 03 well was found in 2009. Therefore, the inhibitor CT2-4 was suggested to be used in the field. The anti-corrosion technology was discussed based on weight loss and electrochemical methods. According to the corrosion environment, the inhibition rate of CT2-4 is higher than 85% when its dosage is more than 125mg/L. The corrosion rate is decreased below 0.076 mm/a. The electrochemical results discover CT2-4 is a mixed-type inhibitor. In order to promote the anti-corrosion efficiency, the pre-film was investigated also. It shows the amount of prefilming and prefilming time are 1250 mg/L and 4h.

scholarly journals Application of HPLC-DAD for In Vitro Investigation of Acetylcholinesterase Inhibition Activity of Selected Isoquinoline Alkaloids from Sanguinaria canadensis Extracts

Molecules ◽  
2021 ◽  
Vol 26 (1) ◽  
pp. 230
Author(s):  
Tomasz Tuzimski ◽  
Anna Petruczynik
Keyword(s):  
Plant Extracts ◽  
High Performance ◽  
Acetylcholinesterase Activity ◽  
Hplc Method ◽  
Acetylcholinesterase Inhibition ◽  
Isoquinoline Alkaloids ◽  
Activity Inhibition ◽  
Sanguinaria Canadensis ◽  
In Vitro Investigation

Isoquinoline alkaloids may have a wide range of pharmacological activities. Some of them have acetylcholinesterase activity inhibition. Nowadays, neurodegenerative disorders such as Alzheimer’s disease have become a serious public health problem. Searching for new effective compounds with inhibited acetylcholinesterase activity is one of the most significant challenges of modern scientific research. The aim of this study was the in vitro investigation of acetylcholinesterase activity inhibition of extracts obtained from Sanguinaria canadensis collected before, during and after flowering. The acetylcholinesterase activity inhibition of these extracts has not been previously tested. The aim was also to quantify selected alkaloids in the investigated extracts by high performance liquid chromatography (HPLC). The analyses of alkaloid content were performed using HPLC in reversed phase (RP) mode using Polar RP column and mobile phase containing acetonitrile, water and ionic liquid (IL). The acetylcholinesterase activity inhibition of the tested plant extracts and respective alkaloid standards were examined using high performance liquid chromatography with diode-array detector (HPLC-DAD) for the quantification of 5-thio-2-nitro-benzoic acid, which is the product of the reaction between the thiocholine (product of the hydrolysis of acetylthiocholine reaction) with Ellman reagent. The application of the HPLC method allowed for elimination of absorption of interfering components, for example, alkaloids such as sanguinarine and berberine. It is revealed that the HPLC method can be successfully used for the evaluation of the acetylcholinesterase inhibitory activity in samples such as plant extracts, especially those containing colored components adsorbing at wavelength in the range 405–412 nm. The acetylcholinesterase inhibition activity synergy of pairs of alkaloid standards and mixture of all investigated alkaloids was also determined. Most investigated alkaloids and all Sanguinaria canadensis extracts exhibited very high acetylcholinesterase activity inhibition. IC50 values obtained for alkaloid standards were from 0.36 for berberine to 23.13 µg/mL for protopine and from 61.24 to 89.14 µg/mL for Sanguinaria canadensis extracts. Our investigations demonstrated that these plant extracts can be recommended for further in vivo experiments to confirm their acetylcholinesterase activity inhibition.

Relative Rates of Color Development of 17-Keto- and Ketogenic Steroids in the Zimmermann Reaction

1965 ◽  
Vol 11 (5) ◽  
pp. 554-562 ◽  
Author(s):  
John HC Liu
Keyword(s):  
Reading Time ◽  
Functional Group ◽  
Reaction Rates ◽  
Color Reaction ◽  
Factors Affecting ◽  
Color Formation ◽  
Color Development ◽  
Rate Of Reaction ◽  
Dependence Theory ◽  
Normal Urine

Abstract The rates of reaction at 27° 37°, 47°, and 57°, of 17-ketosteroids (17-KS), dehydroisoandrosterone (DHA), and 17-ketogenic steroids (17-KGS) were studied by a modified Zimmermann color reaction. Curves were constructed by plotting absorbance against time necessary for maximum color development at these temperatures. Pooled eluates of 17-KS and 17-KGS from normal urine samples were used in the determinations. Temperature was plotted against the time found necessary for maximum color development using DHA as standard. Experimental results conformed to the temperature-dependence theory of reaction rates, that for every 10° rise, the rate of reaction doubles. Curves of the absorbances at various times of incubation were calculated as percentiles of maximum color formation at each temperature. The interrelationship between 17-KS, 17-KGS, and DHA with respect to optimum reading time was noted. The significance of the finding that the rate of reaction of 17-KGS is much greater than that of 17-KS and DHA is demonstrated. Functional group contribution to the rate of reaction is discussed, as are other factors affecting the Zimmermann color reaction.

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