An Update on Distal C( sp 3 )−H Functionalization Involving 1,5‐HAT Emerging from Nitrogen Radicals

2020 ◽  
Vol 60 (3-4) ◽  
pp. 303-312 ◽  
Author(s):  
Nupur Goswami ◽  
Debabrata Maiti
Keyword(s):  
Nitrogen Radicals

scholarly journals Virulent Mycobacterium fortuitum Restricts NO Production by a Gamma Interferon-Activated J774 Cell Line and Phagosome-Lysosome Fusion

2002 ◽  
Vol 70 (10) ◽  
pp. 5628-5634 ◽  
Author(s):  
Tânia Regina Marques da Silva ◽  
Juliana Ribeiro de Freitas ◽  
Queilan Chagas Silva ◽  
Cláudio Pereira Figueira ◽  
Eliana Roxo ◽  
...  
Keyword(s):  
Gamma Interferon ◽  
No Production ◽  
Mycobacterium Fortuitum ◽  
Vitro Assay ◽  
J774 Cells ◽  
Nitrogen Radicals ◽  
Ifn Γ ◽  
Phagosome Fusion ◽  
J774 Cell Line

ABSTRACT The virulence of different isolates of Mycobacterium has been associated with two morphologically distinguishable colonial variants: opaque (SmOp) and transparent (SmTr). In this report we used an in vitro assay to compare macrophage (Mφ) responses to SmOp and SmTr Mycobacterium fortuitum variants, taking advantage of the fact that these variants were derived from the same isolate. Cells preactivated or not with gamma interferon (IFN-γ) were infected with SmOp or SmTr M. fortuitum. We showed that SmOp and SmTr induced different levels of nitric oxide (NO) production by IFN-γ-stimulated Mφ. Indeed, the amount of IFN-γ-induced NO production by J774 cells was 4.8 to 9.0 times higher by SmOp (23.1 to 37.7 μM) compared to SmTr infection (3.9 to 4.8 μM) (P = 0.0332), indicating that virulent SmTr bacilli restricted NO production. In addition, IFN-γ-induced NO production by Mφ was higher when correlated with reduction of only avirulent SmOp bacillus viability. SNAP (S-nitroso-N-acetyl-dl-penicillamine)-induced NO production did not modify SmTr viability, indicating its resistance to nitrogen radicals. Electron microscopy studies were performed to evaluate the capacity of phagosomes to fuse with lysosomes labeled with bovine serum albumin-colloidal gold particles. By 24 h postinfection, 69% more phagosome-containing SmOp variant had fused with lysosomes compared to the SmTr-induced phagosomes. In conclusion, these data indicate that virulent SmTr bacilli may escape host defense by restricting IFN-γ-induced NO production, resisting nitrogen toxic radicals, and limiting phagosome fusion with lysosomes.

Oxidative Injury by Oxygen and Nitrogen Radicals in Diabetic Retinopathy in the BBZ/WOR Rat: CytoChemical and ImmunoCytochemical Studies

1999 ◽  
Vol 5 (S2) ◽  
pp. 482-483
Author(s):  
E. Ann Ellis ◽  
Maria B. Grant ◽  
Dennis L. Guberski
Keyword(s):  
Nitric Oxide ◽  
Oxygen Radicals ◽  
Nadh Oxidase ◽  
Blood Retinal Barrier ◽  
Complications Of Diabetes ◽  
Toxic Species ◽  
Nondiabetic Control ◽  
Nitrogen Radicals ◽  
Immunocytochemical Studies ◽  
Oxide Synthase

Previous studies have documented NADH oxidase as a source of the oxygen radicals, superoxide (O2) and hydrogen peroxide (H2O2), at sites of disruption of the blood retinal barrier (BRB) in a rat model of noninsulin dependent diabetes (NIDDM). Excess production of nitric oxide (NO) by inducible nitric oxide synthase (iNOS) has been implicated in the complications of diabetes. The effects of NO depend on its microenvironment and one mechanism for its role in complications of diabetes is interaction with oxygen radicals to form the toxic species, peroxynitrite (ONOO−). Since NO is a highly labile molecule, its potential localization is best achieved by immunocytochemical studies of NOS. The activity of iNOS can be detected by localization of nitrotyrosine, a marker indicative of the formation and activity of ONOO−.Colloidal gold labeled immunocytochemical studies of iNOS and nitrotyrosine were done on sections of neural retina in eyes of obese, NIDDM BBZ/Wor rats in which NADH oxidase had been localized with cerium perhydroxide. Disruption of the BRB was documented by immunocytochemical localization of extravasated endogenous serum albumin. Age matched, nondiabetic control retinas were from eyes from BBDR/Wor rats.

scholarly journals Extraction of flavanones from immature Citrus unshiu pomace: process optimization and antioxidant evaluation

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Dong-Shin Kim ◽  
Sang-Bin Lim
Keyword(s):  
Reactive Nitrogen Species ◽  
Ethanol Concentration ◽  
Antioxidant Activities ◽  
Ethanol Extract ◽  
Dietary Guidelines ◽  
Citrus Unshiu ◽  
Oxygen Species ◽  
Antioxidant Evaluation ◽  
Nitrogen Radicals ◽  
Assay Methods

AbstractDietary guidelines recommend the consumption of flavonoid-rich extracts for several health benefits. Although immature Citrus unshiu pomace (ICUP) contains high levels of flavanone glycosides, many studies have concentrated on the optimization of flavonoid extraction from mature citrus peels. Therefore, we developed an optimized extraction method for hesperidin and narirutin from ICUP, and evaluated their antioxidant activities using ten different assay methods. The extraction conditions for the highest flavonoid yields based on a response surface methodology were 80.3 °C, 58.4% (ethanol concentration), 40 mL/g (solvent/feed), and 30 min, where the hesperidin and narirutin yields were 66.6% and 82.3%, respectively. The number of extractions was also optimized as two extraction steps, where the hesperidin and narirutin yields were 92.1% and 97.2%, respectively. Ethanol was more effective than methanol and acetone. The ethanol extract showed high scavenging activities against reactive oxygen species but relatively low scavenging activities for nitrogen radicals and reactive nitrogen species. The antioxidant activities showed a higher correlation with hesperidin content than narirutin content in the extracts. This study confirms the potential of an optimized method for producing antioxidant-rich extracts for the functional food and nutraceutical industries.

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