Activation of oxygen

Autophagy and DNA repair are two essential biological mechanisms that maintain cellular homeostasis. Impairment of these mechanisms was associated with several pathologies such as premature aging, neurodegenerative diseases, and cancer. Intrinsic or extrinsic stress stimuli (e.g., reactive oxygen species or ionizing radiation) cause DNA damage. As a biological stress response, autophagy is activated following insults that threaten DNA integrity.

18p thiencuuchu 27-11-2021 11 1   Download

In this study, pellets of iron alumina pillared bentonite (PFeAPB) were prepared by dispersing iron ions on alumina pillared bentonite pellet. Catalyst activity and lifetime were investigated via efficiencies of Methyl Orange (MO) decolorization and Chemical Oxygen Demand (COD) removal, a typical dye type of textile wastewater. Characteristics of the PFeAPB catalyst were examined by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area, and X-ray fluorescence (XRF).

9p larachdumlanat127 02-01-2021 20 2   Download

The degradation and mineralization efficiency of NB in the systems looked at in this study were determined by measuring the NB concentration and COD values before and after reaction. The influence of pH, Fe(0)-mass and EDTA on the degradation and mineralization efficiencies were also investigated.

7p tamynhan8 04-11-2020 10 2   Download

In this work, nanoscale bimetallic PtNi, PtCo, PtCu catalysts on carbon Vulcan XC72R as supports were synthesized by reduction method under ultrasonic irradiation. The morphology, structure and specific area of synthesized materials were characterized by X-Ray diffraction (XRD), transmission electron microscopy (TEM). The catalytic activity for oxygen reduction reaction (ORR) of PtM/C was investigated by CV and linear sweep voltammetry (LSV) under simulated fuel cell working conditions.

8p abcxyz123_02 03-03-2020 9 1   Download

An investigation into the treatment efficiency of real piggery wastewater of a benchscale aerobic membrane bioreactor was performed. The experiments were aimed to evaluate the effects of hydraulic retention time and activated sludge concentration. The piggery wastewater having high chemical oxygen demand, ammonium and total phosphorus concentrations (about 4200 mg/l, 320 mg/L and 48 mg/L, respectively) was employed.

7p vinhsolax 15-09-2019 37 1   Download

The results of the reaction of selective reduction of NOx by C3H6 on the catalyst Cu/ZSM-5 with the presence of oxygen shown that there was a monotone relation between conversion degree of NOx and the amount of chemically adsorbed NOx [1]. Besides, the existence of amount of irreversiblely adsorbed C3H6 (C3H6ir) on the surface of catalyst Cu/ZSM-5 was detected [2]. The results of the role of C3H6irr towards reduction activity NOx in the studied reaction is presented in this article.

4p uocvong04 24-09-2015 25 3   Download

Large-pore three-dimensional (3D) mesoporous silicas are among the most interesting mesoporous materials discovered in recent years, and they have attracted much attention for potential applications requiring easily accessible, uniform and large pores. Examples of these are SBA-15 (p6 mm) and SBA-16 (Im3m), which have cylindrical- and cage-type structures, respectively.

5p uocvong01 24-09-2015 54 4   Download

Recovering useful hydrocarbons from sewage sludge using zirconia-supporting iron oxide catalysts was investigated. Zirconia has activity for decomposing water molecules to generate active oxygen and hydrogen species.

6p tuananhhumg 04-11-2013 37 2   Download

Microcalorimetry and UV-vis spectroscopy were used to conduct thermodynamic and kinetic investigations of the scission of calf thymus DNA catalyzed by bleomycin A5 (BLM-A5) in the presence of ferrous ion and oxygen. The molar reaction enthalpy for the cleavage, the Michaelis– Menten constant for calf thymus DNA and the turnover number of BLM-A5 were calculated by a novel thermokinetic method for an enzyme-catalyzed reaction to be )577 ± 19 kJÆmol)1, 20.4 ± 3.8 lM and 2.28 ± 0.49 · 10)2 s)1, respectively, at 37.0 °C. This DNA cleavage was a largely exothermic reaction....

9p system191 01-06-2013 31 4   Download

The Na+-translocating NADH:quinone oxidoreductase (Na+-NQR) from Vibrio alginolyticus was inactivated by reactive oxygen species. Highest Na+-NQR activity was observed in anaerobically prepared membranes that exhibited 1 : 1 coupling of NADH oxidation and Q reduction activities (1.6 UÆmg)1). Optical and EPR spectroscopy documented the presence of b-type cytochromes, a [2Fe)2S] cluster and an organic radical signal in anaerobically pre- pared membranes from V. alginolyticus.

6p research12 01-06-2013 46 4   Download

Flavonols are produced by the desaturation of flavanols catalyzed by flavonol synthase. The enzyme belongs to the class of intermolecular dioxygenases which depend on molecular oxygen and Fe II /2-oxoglutarate for activity, and have been in focus of structural studies recently. Flavonol synthase cDNAs were cloned from six plant species, but none of the enzymes had been studied in detail.

9p research12 23-04-2013 44 4   Download

Reactionof certainpeptides andproteinswithsingletoxygen (generated by visible light in the presence of rose bengal dye) yields long-lived peptide and protein peroxides. Incubation of these peroxides with glyceraldehyde-3-phosphate dehy-drogenase, in the absence of addedmetal ions, results in loss of enzymatic activity. Comparative studies with a range of peroxides have shown that this inhibition is concentration, peroxide, and time dependent, with H2O2less ecient than some peptide peroxides.

10p research12 23-04-2013 38 4   Download

Soluble methane mono-oxygenase (sMMO) ofMethylo-coccus capsulatus (Bath) catalyses the O2-dependent and NAD(P)H-dependent oxygenation of methane and numer-ous other substrates. During puri®cation, the sMMO enzyme complex, which comprises three components and has a molecular mass in excess of 300 kDa, becomes inac-tivated because of cleavage of just 12 amino acids from the N-terminus of proteinB, which is the smallest component of sMMOand theonlyonewithout prosthetic groups.

9p research12 23-04-2013 24 3   Download

This paper describes the cloning of the genes coding for each component of the complex of toluene/o-xylene monooxy-genase fromPseudomonas stutzeriOX1, their expression, purification and characterization. Moreover, the reconsti-tution of the active complex from the recombinant subunits has been obtained, and the functional role of each compo-nent in the electron transfer from the electron donor to molecular oxygen has been determined.

11p tumor12 22-04-2013 42 3   Download

Self-regulation of the 2-oxo acid dehydrogenase complexes during catalysiswas studied.Radical species as sideproducts of catalysis were detected by spin trapping, lucigenin fluor-escence and ferricytochromec reduction. Studies of the complexes after converting the bound lipoate or FAD cofactors tononfunctional derivatives indicated that radicals are generated viaFAD. In the presence of oxygen, the 2-oxo acid, CoA-dependent production of the superoxide anion radical was detected.

12p tumor12 22-04-2013 36 3   Download

Reactive oxygen species (ROS) are products of normal metabolic activities and are thought to be the cause of many diseases. A selenium-containing single-chain abzyme 2F3 (Se-2F3-scFv) that imitates glutathione peroxidase has been produced which has the capacity to remove ROS. To evaluate the antioxidant ability of Se-2F3-scFv, we con-structeda ferrous sulfate/ascorbate (Vc/Fe 2+ )-inducedmito-chondrial damage model system and investigated the capacity of Se-2F3-scFv to protect mitochondria from oxi-dative damage.

6p tumor12 20-04-2013 33 4   Download

The oxygen-evolving photosystem II (PS II) complex of red algae contains four extrinsic proteins of 12 kDa, 20 kDa, 33 kDa and cytc-550, among which the 20 kDa protein is unique in that it is not found in other organisms.We cloned the gene for the 20-kDa protein from a red algaCyanidium caldarium. The gene consists of a leader sequence which can be divided into two parts: one for transfer across the plastid envelope and the other for transfer into thylakoid lumen, indicating that the gene is encoded by the nuclear genome....

8p tumor12 20-04-2013 46 2   Download

Tyrosinase (monophenol,L-DOPA:oxygen oxidoreductase) was isolated from the ink of the squid,Illex argentinus. Squid tyrosinase, termed ST94, was found to occur as a covalently linked homodimeric protein with a molecular mass of 140.2 kDa containing two copper atoms per a subunit. The tyrosinase activity of ST94 was enhanced by proteolysis with trypsin to form a protein, termed ST94t, with a molecular mass of 127.6 kDa.

13p tumor12 20-04-2013 30 3   Download

The plastid terminal oxidase (PTOX) encoded by theAra-bidopsis IMMUTANSgenewas expressed inEscherichia coli cells and its quinone/oxygen oxidoreductase activity moni-tored in isolated bacterial membranes using NADH as an electron donor. Specificity for plastoquinone was observed. Neither ubiquinone, duroquinone, phylloquinone nor ben-zoquinone could substitute for plastoquinone in this assay. However, duroquinol (fully reduced chemically) was an accepted substrate. Iron is also required and cannot be substituted by Cu 2+ ,Zn 2+ or Mn 2+ . ...

8p tumor12 20-04-2013 40 4   Download

In Klebsiella pneumoniae, the flavoprotein, NifL regulates NifA mediated transcriptional activation of the N2-fixation (nif) genes in response tomolecular O2and ammonium.We investigated the influence of membrane-bound oxidoreduc-tases on nif-regulation by biochemical analysis of purified NifLandbymonitoringNifA-mediated expressionofnifH¢-¢lacZ reporter fusions in different mutant backgrounds. NifL-bound FAD-cofactor was reduced by NADH only in the presence of a redox-mediator or inside-out vesicles derived from anaerobically grown K.pneumoniaecells,...

12p tumor12 20-04-2013 33 4   Download