The In Vitro Invasion Inhibition Assay (IIA) for Plasmodium vivax

2015 ◽  
pp. 187-196 ◽  
Author(s):  
Wanlapa Roobsoong
Keyword(s):  
Plasmodium Vivax ◽  
Inhibition Assay ◽  
In Vitro Invasion ◽  
Invasion Inhibition

scholarly journals Catalytic activity and stereoselectivity of engineered phosphotriesterases towards structurally different nerve agents in vitro

2021 ◽  
Author(s):  
Anja Köhler ◽  
Benjamin Escher ◽  
Laura Job ◽  
Marianne Koller ◽  
Horst Thiermann ◽  
...  
Keyword(s):  
Plasma Clearance ◽  
Nerve Agents ◽  
Inhibition Assay ◽  
Ache Inhibition ◽  
Catalytic Activities ◽  
Chiral Lc ◽  
Hydrolysis Of ◽  
Medical Countermeasures

AbstractHighly toxic organophosphorus nerve agents, especially the extremely stable and persistent V-type agents such as VX, still pose a threat to the human population and require effective medical countermeasures. Engineered mutants of the Brevundimonas diminuta phosphotriesterase (BdPTE) exhibit enhanced catalytic activities and have demonstrated detoxification in animal models, however, substrate specificity and fast plasma clearance limit their medical applicability. To allow better assessment of their substrate profiles, we have thoroughly investigated the catalytic efficacies of five BdPTE mutants with 17 different nerve agents using an AChE inhibition assay. In addition, we studied one BdPTE version that was fused with structurally disordered PAS polypeptides to enable delayed plasma clearance and one bispecific BdPTE with broadened substrate spectrum composed of two functionally distinct subunits connected by a PAS linker. Measured kcat/KM values were as high as 6.5 and 1.5 × 108 M−1 min−1 with G- and V-agents, respectively. Furthermore, the stereoselective degradation of VX enantiomers by the PASylated BdPTE-4 and the bispecific BdPTE-7 were investigated by chiral LC–MS/MS, resulting in a several fold faster hydrolysis of the more toxic P(−) VX stereoisomer compared to P(+) VX. In conclusion, the newly developed enzymes BdPTE-4 and BdPTE-7 have shown high catalytic efficacy towards structurally different nerve agents and stereoselectivity towards the toxic P(−) VX enantiomer in vitro and offer promise for use as bioscavengers in vivo.

The EYTEX™ System and the Neutral Red Uptake Inhibition Assay in Cultured Hep G2 Cells as Alternative Methods for In Vivo Eye Irritation Following the EEC Protocol

1990 ◽  
Vol 17 (4) ◽  
pp. 325-333
Author(s):  
Paul J. Dierickx ◽  
Virginia C. Gordon
Keyword(s):  
Neutral Red ◽  
Alternative Methods ◽  
Inhibition Assay ◽  
Hep G2 ◽  
Hep G2 Cells ◽  
Eye Irritation ◽  
Uptake Inhibition ◽  
In Vitro Methods ◽  
Neutral Red Uptake

The neutral red uptake inhibition assay and the EYTEX™ system were investigated as alternative methods for the assessment of eye irritation, determined according to the EEC protocol. The 17 test chemicals used were mainly organic solvents. The xenobiotics were applied to Hep G2 cells for 24 hours at different concentrations. Neutral red uptake inhibition was then measured. The results are expressed as the NI50 value, which is the concentration of test compound required to induce a 50% reduction in neutral red uptake. The same chemicals were also tested as coded samples by the EYTEX™ test according to the manufacturer's directions. A nearly identical quantitative correlation was found for both in vitro methods with corneal opacity scores: r = 0.84 for EYTEX™ scores and r = 0.83 for log NI50, expressed in μg/ml. Whilst these correlations are certainly not perfect, it is clear that both in vitro methods can be used as valuable prescreening methods.

A Continuous, Long-Term Plasmodium vivax In Vitro Blood-Stage Culture: What Are We Missing?

2017 ◽  
Vol 33 (12) ◽  
pp. 921-924 ◽  
Author(s):  
Richard Thomson-Luque ◽  
Katy Shaw Saliba ◽  
Clemens H.M. Kocken ◽  
Erica M. Pasini
Keyword(s):  
Plasmodium Vivax ◽  
Blood Stage

scholarly journals In VitroAnti-Plasmodial Activity ofTrigonella foenum–graecumL.

2010 ◽  
Vol 7 (4) ◽  
pp. 441-445 ◽  
Author(s):  
M. Palaniswamy ◽  
B. V. Pradeep ◽  
R. Sathya ◽  
J. Angayarkanni
Keyword(s):  
Ethanol Extract ◽  
Traditional Healers ◽  
Active Principle ◽  
Test Plant ◽  
Moderate Activity ◽  
Inhibition Assay ◽  
Phytochemical Screening ◽  
Solvent Systems ◽  
Fenugreek Leaves

Developing countries, where malaria is one of the most prevalent diseases, still rely on traditional medicine as a source for the treatment of this disease. For the present study,Trigonella foenum-graecumL. (fenugreek) were collected from Coimbatore, Tamilnadu, India. The test plant has been used in India by traditional healers for the treatment of fever as well as other diseases. The active principle was extracted out in different solvent systems to assess the anti-plasmodial potential, with an aim that they can further be utilized to formulate drugs.In vitroanti-plasmodial assay of the extracted fractions of fenugreek leaves was carried out using laboratory adapted chloroquine sensitive and resistantPlasmodium falciparumisolates. Schizont maturation inhibition assay was adopted to analyze the potential of the extracts. Ethanol extract (50%) seemed to possess profound anti-plasmodial activity with IC50value of 8.75 ± 0.35 µg ml−1and 10.25 ± 0.35 µg ml−1against chloroquine sensitive and resistantP. falciparumisolates, respectively. Among the investigated six fractions of the plant extracts, two were found to have significant anti-plasmodial activity with IC50values <10 µg ml−1, namely ethanol and butanol extracts. Two extracts chloroform and ethyl acetate showed moderate activity with IC50values ranging from 10 to 20 µg ml−1, and the other two extracts, hexane and water appeared to be inactive with IC50values >85 µg ml−1. In addition, preliminary phytochemical screening of the various extracts indicated the presence of alkaloids, saponin, tannin like phenolic compounds, flavonoids and steroids.

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