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Fluorescence in Histochemical Reactions
Published in Victoria Vladimirovna Roshchina, Fluorescence of Living Plant Cells for Phytomedicine Preparations, 2020
Victoria Vladimirovna Roshchina
An indirect fluorescent method for the determination of cholinesterase activity in the medicinal species Artemisia tridentate Nutt. (Turi et al. 2014) was applied using the artificial reagent 10-acetyl-3,7-dihydroxyphenoxazine (Amplex® Red reagent), a sensitive fluorogenic probe for hydrogen peroxide. Acetylcholinesterase converts the acetylcholine substrate to choline, which is then oxidized by choline oxidase (present in the mixture) to betaine and hydrogen peroxide. The emission is observed at 590 nm (excitation 530–560 nm). It should be noted that this fluorescent method has not yet been used in plant histochemistry.
Liver Diseases
Published in George Feuer, Felix A. de la Iglesia, Molecular Biochemistry of Human Disease, 2020
George Feuer, Felix A. de la Iglesia
Lipotropic factors (choline and methionine) and protein influence alcohol-induced steatosis. In growing rats, the lack of protein or lipotropic factors produces fatty liver.38 Primates, however, are less susceptible to protein and lipotrope deficiency than rodents.257 Treatment of patients suffering from alcoholic liver disease with choline is ineffective.483 The reason for this discrepancy is that primate and human liver contain very little choline oxidase activity as compared to rodent liver. Protein deficiency also affects the liver. In children, protein deficiency leads to steatosis. In volunteers, however, excess protein cannot prevent fat accumulation brought about by ethanol consumption.355 Ethanol impairs methionine conservation in circumstances of protein deficiency by increasing the activities of hepatic cystathionine synthetase and 5-methyltetrahydrofolate-homocysteine methyltransferase.178 In baboons and alcoholic patients, the alcohol-induced liver injury is associated with increased branched-chain amino acids and γ-amino-n-butyric acid. Following intestinal bypass for obesity, the absorption of dietary protein is reduced and plasma γ-amino-n-butyric acid branched-chain amino acids and essential amino acids, such as threonine, lysine and phenylalanine, are decreased, whereas nonessential amino acids such as glycine and serine are elevated.413 In alcoholics characteristically, the plasma level of γ-amino-n-butyric acid is enhanced.508
ExperimentaL Oral Medicine
Published in Samuel Dreizen, Barnet M. Levy, Handbook of Experimental Stomatology, 2020
Samuel Dreizen, Barnet M. Levy
Trefz130 investigated the hypothesis that intracellular enzymes contribute in the transduction of tastes to electrical impulses by the taste cells. A histochemical survey was made in rhesus monkeys of the activity of 14 enzymes in taste buds associated with sweet, salt, sour, and bitter reception. All monkeys were killed by vascular perfusion of isoosmotic saline while under anesthesia. Tongues were incised posterior to the circumvallate papillae, and immediately thereafter regions containing taste buds were removed from well within areas classically assigned to each modality. Tissues were frozen in liquid nitrogen and sectioned on a cryostat; 14 different enzyme systems were analyzed histochemically in the tissue sections, as follows: for Krebs cycle activity — succinic dehydrogenase; for electron transport chain activity — choline oxidase, cytochrome oxidase, α-glycerophosphate dehydrogenase, β-hydroxybutyric dehydrogenase, and D-amino acid oxidase; for membrane-bound hydrolytic activity — nonspecific esterase; for membrane-bound pentose-phosphate shunt activity — NAD diaphorase and NADP diaphorase; for soluble pentose-phosphate shunt activity — glucose-6-phosphate dehydrogenase; for mitochondrial activity — adenosine triphosphatase; for Golgi complex activity — nucleotide diphosphatase; for active transport activity — alkaline phosphatase; for lysosomal activity — acid phosphatase.
Recent advances in electrochemical and optical sensing of the organophosphate chlorpyrifos: a review
Published in Critical Reviews in Toxicology, 2022
Athira Sradha S, Louis George, Keerthana P, Anitha Varghese
A CL sensor was developed using N-(4-Aminobutyl)-N-ethylsoluminol/Co2+/Chitosan hydrogels with MOF-Pt as catalyst. The hydrogels were able to produce long-lasting CL due to their high viscosity resulting in slow diffusion of molecules. AChE catalyzed acetylcholine chloride substrate to produce an intermediate product, choline. Choline oxidase further catalyzed this intermediate product to form betaine and H2O2. H2O2 then reacted with the hydrogel/MOF-Pt to produce a strong CL signal. In the presence of CP, due to the inhibition of AChE, the H2O2 production was significantly reduced resulting in decreased CL signal. It was observed that 60% of the signal intensity was maintained after 2 h (Lu et al. 2020).
Dynamics and metabolic profile of oral keratinocytes (NOK-si) and Candida albicans after interaction in co-culture
Published in Biofouling, 2021
Paula Masetti, Paula Volpato Sanitá, Janaina Habib Jorge
The quantification of phospholipase production by C. albicans biofilm was performed using the fluorimetric kit Amplex Red® Phosphatidylcholine-Specific Phospholipase C Assay (Molecular Probe, Eugene, OR, USA), according to the manufacturer's recommendations. For this, the pellets were individually resuspended in lysis buffer (2 M Tris-HC1, 1MCaC12, ultra-pure water, pH 7.4), vortexed for 20 s for disruption, and centrifuged for 5 min at ∼11,180 RCF to obtain the lysates. The working solution was obtained by adding 200 µl of Amplex Red® reagent (20 mM), 100 µl of horseradish peroxidase, 200 µl of alkaline phosphatase, 100 µl of choline oxidase, and 78 µl of lecithin in 9.32 ml of the buffer digestion (1:5). Then, 100 µl of the lysate and of the working solution were pipetted in triplicate into the wells of a 96-well plate for fluorescence testing. The plate was incubated at 37 °C for 3 h (protected from light) and the fluorescence reading was performed in a microplate reader with excitation at 544 nm and emission at 590 nm. The values obtained were compared with the fluorescence values of the positive controls provided by the manufacturer.
Gold nanoparticles applications: from artificial enzyme till drug delivery
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Kazem Golchin, Jafar Golchin, Shahrooz Ghaderi, Neda Alidadiani, Sajjad Eslamkhah, Masoud Eslamkhah, Soodabeh Davaran, Abolfazl Akbarzadeh
An esterase is a hydrolase enzyme that ruptures esters into an acid and an alcohol in a chemical reaction in water. The reaction is called hydrolysis [40]. According to evidence, the first example of peptide-functionalized GNPs is hydrolytically active against carboxylate esters. The active units are constituted by His-Phe-OH terminating thiols [41,42]. A highly sensitive and selective fluorescent assay for the detection of acetylcholine (ACh) was developed based on enzyme mimics of Au/Ag NPs [43]. This mechanism involved is the following: reacting ACh with acetylcholinesterase (AChE) to form choline that is in turn oxidized by choline oxidase (ChOx) to produce betaine and H2O2, which reacts with Amplex UltraRed (AUR) in the presence of bimetallic NPs catalyst to form a fluorescent product [44].