Elicitation of tropane alkaloid synthesis in root culture of Hyoscyamus by hydrogen peroxide and ascorbic acid

Planta Medica ◽  
2007 ◽  
Vol 73 (09) ◽  
Author(s):  
R Zayed
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Root Culture ◽  
Tropane Alkaloid ◽  
Alkaloid Synthesis

Synthesis and Characterization of Silver Nanoplates by a Seed-mediated Method

2019 ◽  
Vol 29 (3) ◽  
Author(s):  
Mai Ngọc Tuan Anh
Keyword(s):  
Hydrogen Peroxide ◽  
Silver Nanoparticles ◽  
Ascorbic Acid ◽  
Silver Nitrate ◽  
Sodium Borohydride ◽  
Trisodium Citrate ◽  
Synthesis And Characterization ◽  
Silver Nanoplates ◽  
Seed Mediated

Silver nanoplates (SNPs) having different size were synthesized by a seed-mediated method. The seeds -silver nanoparticles with 4 – 6 nm diameters were synthesized first by reducing silver nitrate with sodium borohydride in the present of Trisodium Citrate and Hydrogen peroxide. Then these seeds were developed by continue reducing Ag\(^+\) ions with various amount of L-Ascorbic acid to form SNPs. Our analysis showed that the concentratrion of L-Ascorbic acid, a secondary reducing agent, played an important role to form SNPs. In addition, the size and in-plane dipole plasmon resonance wavelenght of silver nanoplates were increased when the concentration of added silver nitrate increased. The characterization of SNPs were studied by UV-Vis, FE-SEM, EDS and TEM methods.

An ESR study of the peroxidase reaction catalyzed by human methaemoglobin and methaemoglobin-haptoglobin complex

1991 ◽  
Vol 56 (4) ◽  
pp. 923-932
Author(s):  
Jana Stejskalová ◽  
Pavel Stopka ◽  
Zdeněk Pavlíček
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Amino Acid ◽  
Peroxidase Activity ◽  
Amino Acid Analysis ◽  
Superoxide Radical ◽  
Esr Spectra ◽  
The Other ◽  
Delocalized Electron

The ESR spectra of peroxidase systems of methaemoglobin-ascorbic acid-hydrogen peroxide and methaemoglobin-haptoglobin complex-ascorbic acid-hydrogen peroxide have been measured in the acetate buffer of pH 4.5. For the system with methaemoglobin an asymmetrical signal with g ~ 2 has been observed which is interpreted as the perpendicular region of anisotropic spectrum of superoxide radical. On the other hand, for the system with methaemoglobin-haptoglobin complex the observed signal with g ~ 2 is symmetrical and is interpreted as a signal of delocalized electron. After realization of three repeatedly induced peroxidase processes the ESR signal of the perpendicular part of anisotropic spectrum of superoxide radical is distinctly diminished, whereas the signal of delocalized electron remains practically unchanged. An amino acid analysis of methaemoglobin along with results of the ESR measurements make it possible to derive a hypothesis about the role of haptoglobin in increasing of the peroxidase activity of methaemoglobin.

scholarly journals Hydrogen Peroxide Induces Hyphal Differentiation in Candida albicans

2008 ◽  
Vol 7 (11) ◽  
pp. 2008-2011 ◽  
Author(s):  
Olviyani Nasution ◽  
Kavitha Srinivasa ◽  
Minsun Kim ◽  
Yeo-Jung Kim ◽  
Wankee Kim ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Candida Albicans ◽  
Intracellular Concentration ◽  
Low Concentrations ◽  
Null Mutants

ABSTRACT In this study, we demonstrate that hyphal differentiation is induced by the subtoxic concentration of exogenous H2O2 in Candida albicans. This finding is confirmed by the changing intracellular concentration of H2O2. In order to induce the same level of differentiation, low concentrations of exogenous H2O2 are required for the null mutants of the thiol-specific antioxidant and catalase, while higher concentrations are needed for cells treated with ascorbic acid, an antioxidant chemical.

scholarly journals Killing of Bacillus Spores by Aqueous Dissolved Oxygen, Ascorbic Acid, and Copper Ions

2003 ◽  
Vol 69 (4) ◽  
pp. 2245-2252 ◽  
Author(s):  
J. B. Cross ◽  
R. P. Currier ◽  
D. J. Torraco ◽  
L. A. Vanderberg ◽  
G. L. Wagner ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Dissolved Oxygen ◽  
Hydroxyl Radicals ◽  
Fenton Reaction ◽  
Copper Ions ◽  
Transition Metal Ions ◽  
Fenton Reagent ◽  
Bacillus Spores ◽  
Modified Fenton

ABSTRACT An approach to decontamination of biological endospores is discussed. Specifically, the performance of an aqueous modified Fenton reagent is examined. A modified Fenton reagent formulation of cupric chloride, ascorbic acid, and sodium chloride is shown to be an effective sporicide under aerobic conditions. The traditional Fenton reaction involves the conversion of hydrogen peroxide to hydroxyl radical by aqueous ionic catalysts such as the transition metal ions. Our modified Fenton reaction involves the conversion of aqueous dissolved oxygen to hydrogen peroxide by an ionic catalyst (Cu2+) and then subsequent conversion to hydroxyl radicals. Results are given for the modified Fenton reagent deactivating spores of Bacillus globigii. A biocidal mechanism is proposed that is consistent with our experimental results and independently derived information found in the literature. This mechanism requires diffusion of relatively benign species into the interior of the spore, where dissolved O2 is then converted through a series of reactions which ultimately produce hydroxyl radicals that perform the killing action.

scholarly journals Electrochemical Sensing of Ascorbic Acid, Hydrogen Peroxide and Glucose by Bimetallic (Fe, Ni)−CNTs Composite Modified Electrode

2019 ◽  
Vol 31 (5) ◽  
pp. 851-857 ◽  
Author(s):  
Sayed Tayyab Raza Naqvi ◽  
Bahareh Shirinfar ◽  
Dilshad Hussain ◽  
Saadat Majeed ◽  
Muhammad Naeem Ashiq ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Modified Electrode ◽  
Electrochemical Sensing
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