A Simple, Universal Colorimetric Assay for Endonuclease/Methyltransferase Activity and Inhibition Based on an Enzyme-Responsive Nanoparticle System

ACS Nano ◽  
2009 ◽  
Vol 3 (5) ◽  
pp. 1183-1189 ◽  
Author(s):  
Guangtao Song ◽  
Cuie Chen ◽  
Jinsong Ren ◽  
Xiaogang Qu
Keyword(s):  
Colorimetric Assay ◽  
Methyltransferase Activity ◽  
Nanoparticle System

Label-Free Colorimetric Assay for Methyltransferase Activity Based on a Novel Methylation-Responsive DNAzyme Strategy

2010 ◽  
Vol 82 (5) ◽  
pp. 1935-1941 ◽  
Author(s):  
Wang Li ◽  
Zhuoliang Liu ◽  
Hui Lin ◽  
Zhou Nie ◽  
Jinhua Chen ◽  
...  
Keyword(s):  
Colorimetric Assay ◽  
Label Free ◽  
Methyltransferase Activity

A colorimetric assay of DNA methyltransferase activity based on the keypad lock of duplex DNA modified meso-SiO2@Fe3O4

2016 ◽  
Vol 920 ◽  
pp. 80-85 ◽  
Author(s):  
Pei Liu ◽  
Kexin Zhang ◽  
Ranran Zhang ◽  
Huanshun Yin ◽  
Yunlei Zhou ◽  
...  
Keyword(s):  
Dna Methyltransferase ◽  
Colorimetric Assay ◽  
Duplex Dna ◽  
Methyltransferase Activity

Label-free colorimetric assay for biological thiols based on ssDNA/silver nanoparticle system by salt amplification

The Analyst ◽  
2010 ◽  
Vol 135 (5) ◽  
pp. 1066 ◽  
Author(s):  
Zhang Chen ◽  
Yejuan He ◽  
Shenglian Luo ◽  
Hailan Lin ◽  
Yufang Chen ◽  
...  
Keyword(s):  
Silver Nanoparticle ◽  
Colorimetric Assay ◽  
Label Free ◽  
Nanoparticle System

scholarly journals A colorimetric assay of DNA methyltransferase activity based on peroxidase mimicking of DNA template Ag/Pt bimetallic nanoclusters

2018 ◽  
Vol 410 (20) ◽  
pp. 4943-4952 ◽  
Author(s):  
Hanie Ahmadzade Kermani ◽  
Morteza Hosseini ◽  
Andrea Miti ◽  
Mehdi Dadmehr ◽  
Giampaolo Zuccheri ◽  
...  
Keyword(s):  
Dna Methyltransferase ◽  
Colorimetric Assay ◽  
Methyltransferase Activity ◽  
Bimetallic Nanoclusters ◽  
Dna Template

Development of a colorimetric protein phosphorylation assay for detecting cyanobacterial toxins

1995 ◽  
Vol 31 (5-6) ◽  
pp. 47-49 ◽  
Author(s):  
C. Ash ◽  
C. MacKintosh ◽  
R. MacKintosh ◽  
C. R. Fricker
Keyword(s):  
Protein Phosphorylation ◽  
Colorimetric Assay ◽  
Cyanobacterial Toxins ◽  
Sensitive Determination

A new colorimetric assay is described, based on inhibition of protein phosphotases, that enables the rapid, simple and sensitive determination of the concentration of toxins from cyanobacteria.

Design, Synthesis, In vitro and In silico Evaluation of New Hydrazonebased Antitumor Agents as Potent Akt Inhibitors

2020 ◽  
Vol 17 (11) ◽  
pp. 1380-1392
Author(s):  
Emine Merve Güngör ◽  
Mehlika Dilek Altıntop ◽  
Belgin Sever ◽  
Gülşen Akalın Çiftçi
Keyword(s):  
Cell Line ◽  
Anticancer Agents ◽  
In Silico ◽  
Antitumor Agents ◽  
Colorimetric Assay ◽  
Fibroblast Cell ◽  
Lipinski’S Rule ◽  
In Silico Docking ◽  
Embryonic Fibroblast

Background: Akt is overexpressed or activated in a variety of human cancers, including gliomas, lung, breast, ovarian, gastric and pancreatic carcinomas. Akt inhibition leads to the induction of apoptosis and inhibition of tumor growth and therefore extensive efforts have been devoted to the discovery of potent antitumor drugs targeting Akt. Objectives: The objective of this work was to identify potent anticancer agents targeting Akt. Methods: New hydrazone derivatives were synthesized and investigated for their cytotoxic effects on 5RP7 H-ras oncogene transformed rat embryonic fibroblast and L929 mouse embryonic fibroblast cell lines. Besides, the apoptotic effects of the most active compounds on 5RP7 cell line were evaluated using flow cytometry. Their Akt inhibitory effects were also investigated using a colorimetric assay. In silico docking and Absorption, Distribution, Metabolism and Excretion (ADME) studies were also performed using Schrödinger’s Maestro molecular modeling package. Results and Discussion: Compounds 3a, 3d, 3g and 3j were found to be effective on 5RP7 cells (with IC50 values of <0.97, <0.97, 1.13±0.06 and <0.97 μg/mL, respectively) when compared with cisplatin (IC50= 1.87±0.15 μg/mL). It was determined that these four compounds significantly induced apoptosis in 5RP7 cell line. Among them, N'-benzylidene-2-[(4-(4-methoxyphenyl)pyrimidin- 2-yl)thio]acetohydrazide (3g) significantly inhibited Akt (IC50= 0.5±0.08 μg/mL) when compared with GSK690693 (IC50= 0.6±0.05 μg/mL). Docking studies suggested that compound 3g showed good affinity to the active site of Akt (PDB code: 2JDO). According to in silico ADME studies, the compound also complies with Lipinski's rule of five and Jorgensen's rule of three. Conclusion: Compound 3g stands out as a potential orally bioavailable cytotoxic agent and apoptosis inducer targeting Akt.

An Effort to Making a Colorimitric Nano-Biosensor for Vibrio cholera Detection

2020 ◽  
Vol 16 (5) ◽  
pp. 793-804
Author(s):  
Naimeh Mahheidari ◽  
Jamal Rashidiani ◽  
Hamid Kooshki ◽  
Khadijeh Eskandari
Keyword(s):  
Gold Nanoparticles ◽  
Colorimetric Assay ◽  
Au Nanoparticle ◽  
Bacteria Detection ◽  
Great Promise ◽  
Bacterial Cells ◽  
Vibrio Cholera ◽  
Minimum Concentration ◽  
Vis Spectroscopy ◽  
Fast Procedure

Background: Today, nanoparticles hold great promise in biomedical researches and applications including bacteria detection. The rapid and sensitive outcomes of bacteria detection strategies using nanoparticle conjugates become determinative, especially in bacterial outbreaks. In the current research, we focused on detecting V. cholera bacteria and its toxin using a thiocyanate/Au nanoparticle. Thiocyanate adsorbed strongly on the surface of gold nanoparticles and changed the surface by enhancing surface plasmon resonance of gold nanoparticles. Objective: This method is tried to introduce a simple and fast procedure to assay vibrio cholera. So, it is observed by the naked eyes as well. Methods: We used two antibodies (Ab) for V. cholera detection: a) a primary antibody conjugated to magnetic nanoparticles (MNPs) for trapping V. cholera bacterial cells, and b) a secondary Abconjugated thiocyanate-GNPs as a colorimetric detector. Then, an immuno-magnetic separation system connected to a colorimetric assay was designed based on the GNPs. The results were measured by ultraviolet-visible (UV-Vis) spectroscopy. Results: The results showed that gold nanoparticles are an appropriate optical assay for detecting biological samples in a minimum concentration and also it can be easily seen by the naked eyes. The linear range of this biosensor is 3.2×104 to 28×104 cells per ml. Conclusion: In this research, a colorimetric immune assay based on gold nanoparticles was designed to improve the sensitivity of V. cholera detection. Also, this method can be used for the detection of other biological agents.

scholarly journals Suitability of the Cyclic Voltammetry Measurements and DPPH• Spectrophotometric Assay to Determine the Antioxidant Capacity of Food-Grade Oenological Tannins

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2925 ◽  
Author(s):  
Arianna Ricci ◽  
Giuseppina Paola Parpinello ◽  
Nemanja Teslić ◽  
Paul Andrew Kilmartin ◽  
Andrea Versari
Keyword(s):  
Cyclic Voltammetry ◽  
Colorimetric Assay ◽  
Radical Scavenging ◽  
Calibration Graph ◽  
Spectrophotometric Assay ◽  
Experimental Conditions ◽  
Fast Analysis ◽  
Cv Measurements ◽  
And Control ◽  
Analytical Approaches

Twenty commercially available oenological tannins (including hydrolysable and condensed) were assessed for their antiradical/reducing activity, comparing two analytical approaches: The 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging spectrophotometric assay and the cyclic voltammetry (CV) electrochemical method. Electrochemical measurements were performed over a −200 mV–500 mV scan range, and integrated anodic currents to 500 mV were used to build a calibration graph with (+)-catechin as a reference standard (linear range: From 0.0078 to 1 mM, R2 = 0.9887). The CV results were compared with the DPPH• assay (expressed as % of radical scavenged in time), showing high correlation due to the similarity of the chemical mechanisms underlying both methods involving polyphenolic compounds as reductants. Improved correlation was observed by increasing the incubation time with DPPH• to 24 h (R2 = 0.925), demonstrating that the spectrophotometric method requires a long-term incubation to complete the scavenging reaction when high-molecular weight tannins are involved; this constraint has been overcome by using instant CV measurements. We concluded that the CV represents a valid alternative to the DPPH• colorimetric assay, taking advantage of fast analysis and control on the experimental conditions and, because of these properties, it can assist the quality control along the supply chain.

The Need for Using An Enzymatic Colorimetric Assay in Creatinine Determination of Peritoneal Dialysis Solutions

1990 ◽  
Vol 10 (1) ◽  
pp. 89-92 ◽  
Author(s):  
Liliane Larpent ◽  
Christian Verger
Keyword(s):  
Peritoneal Dialysis ◽  
Reliable Method ◽  
Colorimetric Assay ◽  
Colorimetric Method ◽  
Peritoneal Membrane ◽  
Creatinine Kinetics ◽  
Dialysis Solutions ◽  
Peritoneal Dialysis Solutions ◽  
Enzymatic Test

The fate of the peritoneal membrane on continuous ambulatory peritoneal dialysis (CAPD) is usually evaluated through the modification of its permeability to various solutes as glucose, creatinine, and urea. Therefore, the accuracy of the methods used for measurements of creatinine is of great importance. A particular problem does exist for creatinine determination as it may be influenced by the presence of glucose. We studied a new enzymatic colorimetric method for creatinine determination in peritoneal dialysis solutions which contain high dextrose concentrations. Creatinine was measured in plasma, urine, and dialysate from 18 patients on CAPD and in pure dextrose solutions, with an enzymatic test (Boehringer Mannheim) and with Jaffe's reaction on two different analyzers: Astra (Beckman) and Eris (Merck). Creatinine results were similar with both assays (Jaffe's reaction and enzymatic test) when measured in blood and urine. However the Jaffe's reaction gave higher creatinine results than the enzymatic test (p < 0.001), when assays were performed in peritoneal dialysis solutions and in pure glucose solutions. In addition, it appeared that other components of dialysis solutions, mainly calcium chloride, influenced unpredictably the results of creatinine with the Jaffe's reaction. We conclude that specific enzymatic test is a more accurate and reliable method to evaluate creatinine kinetics through the peritoneal membrane when determined in CAPD solutions.

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