scholarly journals EPR Imaging Spin Probe Trityl Radical OX063: A Method for Its Isolation from Animal Effluent, Redox Chemistry of Its Quinone Methide Oxidation Product, and in Vivo Application in a Mouse

2016 ◽  
Vol 29 (12) ◽  
pp. 2153-2156 ◽  
Author(s):  
Maciej Serda ◽  
Yen-Ku Wu ◽  
Eugene D. Barth ◽  
Howard J. Halpern ◽  
Viresh H. Rawal
Keyword(s):  
Oxidation Product ◽  
Spin Probe ◽  
Redox Chemistry ◽  
Quinone Methide ◽  
Trityl Radical

In vivo EPR extracellular pH-metry in tumors using a triphosphonated trityl radical

2016 ◽  
Vol 77 (6) ◽  
pp. 2438-2443 ◽  
Author(s):  
Valérie Marchand ◽  
Philippe Levêque ◽  
Benoit Driesschaert ◽  
Jacqueline Marchand-Brynaert ◽  
Bernard Gallez
Keyword(s):  
Extracellular Ph ◽  
In Vivo Epr ◽  
Trityl Radical ◽  
Ph Metry

Studies on the dehydrogenative polymerization of monolignol β-glycosides. Part 6: Monitoring of horseradish peroxidase-catalyzed polymerization of monolignol glycosides by GPC-PDA

Holzforschung ◽  
2010 ◽  
Vol 64 (2) ◽  
Author(s):  
Yuki Tobimatsu ◽  
Toshiyuki Takano ◽  
Hiroshi Kamitakahara ◽  
Fumiaki Nakatsubo
Keyword(s):  
Horseradish Peroxidase ◽  
Reaction System ◽  
Water Soluble ◽  
Quinone Methide ◽  
Efficient Production ◽  
Hydroxyl Groups ◽  
Photodiode Array Detection ◽  
Dehydrogenative Polymerization

Abstract Horseradish peroxidase (HRP)-catalyzed dehydrogenative polymerization of guaiacyl (G) and syringyl (S)-type monolignol γ-O-glucosides, isoconiferin (iso-G) and isosyringin (iso-S), which contain a hydrophilic glucosyl unit on γ-position of coniferyl alcohol and sinapyl alcohol, respectively, was monitored by gel permeation chromatography coupled with photodiode array detection (GPC-PDA). Contrary to the conventional dehydrogenative polymerization of monolignols, the polymerization of the glycosides produces water-soluble synthetic lignins (DHPs) in a homogeneous aqueous phase. Taking advantage of this unique reaction system, the method was developed to follow the changes of molecular weights in the course of DHP formations. Moreover, PDA detection permits determination of oligomeric S-type quinone methide intermediates (QMs) formed as stable transient compounds during polymerization of iso-S. A detailed comparison of the polymerization profiles revealed entirely different behaviors of G- and S-type monomers. The data strongly support the view that the low reactivity of oligomeric S-type QMs impedes the formation of DHPs from S-type monomers. In copolymerization of G- and S-type monomers, it is conceivable that G-type phenolic hydroxyl groups serve as good nucleophilic reactants to scavenge S-type QMs resulting in efficient production of DHPs. As a consequence, the present approach can be a powerful tool to study the in vitro dehydrogenative polymerization providing further mechanistic insights into lignin polymerization in vivo.

scholarly journals Nanotechnology-Based Celastrol Formulations and Their Therapeutic Applications

2021 ◽  
Vol 12 ◽  
Author(s):  
Pushkaraj Rajendra Wagh ◽  
Preshita Desai ◽  
Sunil Prabhu ◽  
Jeffrey Wang
Keyword(s):  
Unmet Need ◽  
Aqueous Solubility ◽  
Clinical Translation ◽  
Quinone Methide ◽  
Root Extract ◽  
Therapeutic Applications ◽  
The Past ◽  
Anti Cancer ◽  
Anti Oxidant

Celastrol (also called tripterine) is a quinone methide triterpene isolated from the root extract of Tripterygium wilfordii (thunder god vine in traditional Chinese medicine). Over the past two decades, celastrol has gained wide attention as a potent anti-inflammatory, anti-autoimmune, anti-cancer, anti-oxidant, and neuroprotective agent. However, its clinical translation is very challenging due to its lower aqueous solubility, poor oral bioavailability, and high organ toxicity. To deal with these issues, various formulation strategies have been investigated to augment the overall celastrol efficacy in vivo by attempting to increase the bioavailability and/or reduce the toxicity. Among these, nanotechnology-based celastrol formulations are most widely explored by pharmaceutical scientists worldwide. Based on the survey of literature over the past 15 years, this mini-review is aimed at summarizing a multitude of celastrol nanoformulations that have been developed and tested for various therapeutic applications. In addition, the review highlights the unmet need in the clinical translation of celastrol nanoformulations and the path forward.

scholarly journals Genetic and biochemical investigations of the role of MamP in redox control of iron biomineralization inMagnetospirillum magneticum

2015 ◽  
Vol 112 (13) ◽  
pp. 3904-3909 ◽  
Author(s):  
Stephanie R. Jones ◽  
Tiffany D. Wilson ◽  
Margaret E. Brown ◽  
Lilah Rahn-Lee ◽  
Yi Yu ◽  
...  
Keyword(s):  
Iron Reduction ◽  
Biochemical Study ◽  
Redox Chemistry ◽  
Loss Of Function ◽  
Redox Sites ◽  
Linear Chains ◽  
Iron Redox ◽  
Magnetite Nanocrystals

Magnetotactic bacteria have evolved complex subcellular machinery to construct linear chains of magnetite nanocrystals that allow the host cell to sense direction. Each mixed-valent iron nanoparticle is mineralized from soluble iron within a membrane-encapsulated vesicle termed the magnetosome, which serves as a specialized compartment that regulates the iron, redox, and pH environment of the growing mineral. To dissect the biological components that control this process, we have carried out a genetic and biochemical study of proteins proposed to function in iron mineralization. In this study, we show that the redox sites ofc-type cytochromes of theMagnetospirillum magneticumAMB-1 magnetosome island, MamP and MamT, are essential to their physiological function and that ablation of one or both heme motifs leads to loss of function, suggesting that their ability to carry out redox chemistry in vivo is important. We also develop a method to heterologously express fully heme-loaded MamP from AMB-1 for in vitro biochemical studies, which show that its Fe(III)–Fe(II) redox couple is set at an unusual potential (−89 ± 11 mV) compared with other related cytochromes involved in iron reduction or oxidation. Despite its low reduction potential, it remains competent to oxidize Fe(II) to Fe(III) and mineralize iron to produce mixed-valent iron oxides. Finally, in vitro mineralization experiments suggest that Mms mineral-templating peptides from AMB-1 can modulate the iron redox chemistry of MamP.

scholarly journals Large-scale synthesis of a monophosphonated tetrathiatriarylmethyl spin probe for concurrent in vivo measurement of pO2, pH and inorganic phosphate by EPR

RSC Advances ◽  
2021 ◽  
Vol 11 (42) ◽  
pp. 25951-25954
Author(s):  
Teresa D. Gluth ◽  
Martin Poncelet ◽  
Stephen DeVience ◽  
Marieta Gencheva ◽  
Emily. H. Hoblitzell ◽  
...  
Keyword(s):  
Inorganic Phosphate ◽  
Spin Probe ◽  
Large Scale ◽  
In Vivo Measurement ◽  
New Strategy ◽  
Large Scale Synthesis ◽  
User Friendly ◽  
Spectrum Fitting

We report a new strategy for the synthesis of a mono-phosphonated triarylmethyl radical spin probe and a standalone application with a user-friendly interface for automatic spectrum fitting and extraction of pO2, pH, and [Pi] values.

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