Oxygen species

Yulangsan (Millettia pulchra Kurz) là một loại thảo dược truyền thống thường được sử dụng phổ biến trong y học dân gian ở khu tự trị Choang Quảng Tây, Trung Quốc. Các nghiên cứu trước đây đã cho thấy rằng polysaccharides chiết xuất từ Yulangsan (YLSP) có khả năng chống gốc tự do hay các chất có phản ứng oxi hóa (Reactive Oxygen Species–ROS) mạnh. Nghiên cứu này nhằm khảo sát tác dụng chống oxi hóa của YLSP trên chuột được gây lão hóa bằng D-galactose.

8p vinatisu 29-08-2024 4 1   Download

The results showed that the overall diffusioncontrolled rate constant is equal to 4.82×109 M-1 s -1 at 298.15K. The zwitterionic form is the main existing form that plays an essential role in the HO - initiated oxidation of Ile (99.98%). The most preponderant reactions are found at C6-H (36.19%) and C8-H (37.77%) positions. Finally, the influence of temperature on the overall rate is also evaluated.

8p dianmotminh02 03-05-2024 7 2   Download

Các gốc tự do thuộc nhóm oxy hoạt động (Reactive oxygen species, ROS) và nhóm nitơ hoạt động (Reactive nitrogen species, RNS) tham gia vào hầu hết các quá trình sống của sinh vật. Nghiên cứu đã tiến hành xác định tiềm năng dược liệu của cây xạ đen được trồng tại tỉnh Tây Ninh, Việt Nam.

6p vimichaelfaraday 28-12-2023 7 3   Download

Các loại oxy hoạt động (Reactive oxygen species-ROS) và nitơ hoạt động (Reactive nitrogen species RNS) là sản phẩm của quá trình trao đổi chất bình thường của tế bào và các tác động có hại của chúng đã bị ngăn chặn bởi một hệ thống chống oxy hóa trong cơ thể. Khi sự cân bằng giữa việc sinh các loại oxy hoạt động, nitơ hoạt động và khả năng của hệ thống chống oxy hóa bị xáo trộn theo hướng tăng ROS và RNS, stress oxy hóa phát sinh. Điều này dẫn đến sự biến đổi các đại phân tử sinh học do bị oxy hóa với hậu quả là làm rối loạn chức năng và cấu trúc tế bào, dẫn đến bệnh tật và lão hóa.

4p viaristotle 26-01-2022 47 3   Download

Esophageal squamous cell carcinoma (ESCC) is the most predominant primary malignant tumor among worldwide, especially in China. To date, the successful treatment remains a mainly clinical challenge, it is imperative to develop successful therapeutic agents.

11p vielonmusk 21-01-2022 17 0   Download

Water quality indicated by chemical oxygen demand, total nitrogen, ammonium nitrogen, and total phosphorus from the effluent complied with the widely accepted limits on domestic wastewater discharge. Our results demonstrate that green roofs can be designed for the ecological treatment of domestic wastewater on the household scale.

10p thebadguys 15-01-2022 7 1   Download

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

Thiết lập quy trình đo hàm lượng ROS trong tinh dịch và dịch huyền phù có tinh trùng sau lọc rửa ở bệnh nhân hiếm muộn và khảo sát mối quan hệ giữa hàm lượng ROS với các thông số tinh dịch đồ là mật độ và tỷ lệ di động tinh trùng.

8p viyerevan2711 16-07-2020 22 2   Download

The objective of this work is to experimentally investigate the effect of the oxygen potential on the fuel and FP chemical behaviour in conditions representative of a severe accident. More specifically, the speciation of Cs, Mo and Ba is investigated.

10p christabelhuynh 29-05-2020 9 2   Download

Magnesium (Mg)-deficiency is one of the most prevalent physiological disorders causing a reduction in Citrus yield and quality. ‘Xuegan’ (Citrus sinensis) seedlings were irrigated for 16 weeks with nutrient solution containing 2 mM (Mg-sufficiency) or 0 mM (Mg-deficiency) Mg(NO3)2.

20p vishikamaru2711 29-04-2020 21 1   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

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

Chlorite dismutase (EC 1.13.11.49), an enzyme capable of reducing chlorite to chloride while producing molecular oxygen, has been characterized using EPR and optical spectroscopy. The EPR spectrum of GR-1 chlorite dis-mutase shows two different high-spin ferric heme species, whichwe have designated
narrow(gx,y,z¼6.24, 5.42, 2.00) and
broad(gz,y,x ¼6.70, 5.02, 2.00).

7p research12 29-04-2013 37 3   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

Human hepatitis delta (HDV) ribozyme is one of small ribozymes, such as hammerhead and hairpin ribozymes, etc. Its secondary structure shows pseudoknot structure com-posed of four stems (I to IV) and three single-stranded regions (SSrA, -B and -C). The 3D structure of 3¢-cleaved product of genomic HDV ribozyme provided extensive information about tertiary hydrogen bonding interactions between nucleotide bases, phosphate oxygens and 2¢OHs including new stem structure P1.1.

12p tumor12 22-04-2013 38 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

Exposure of mammalian cells to oxidant stress causes early (iron catalysed) lysosomal rupture followed by apoptosis or necrosis. Enhanced intracellular production of reactive oxygen species (ROS), presumably of mitochondrial origin, is also observed when cells are exposed to nonoxidant pro-apoptotic agonists of cell death. We hypothesized that ROS generation in this latter case might promote the apoptotic cascade and could arise from effects of released lysosomal materials on mitochondria.

9p tumor12 20-04-2013 30 1   Download

The transport of oxygen in the hemolymph of many arth-ropod and mollusc species is mediated by large copper-proteins that are referred to as hemocyanins. Arthropod hemocyanins are composed of hexamers and oligomers of hexamers. Arachnid hemocyanins usually form 4·6-mers consisting of seven distinct subunit types (termed a–g), although in some spider taxa deviations from this standard scheme have been observed.

8p tumor12 20-04-2013 36 4   Download

Ascorbic acid is often regarded as an antioxidantin vivo, where it protects against cancer by scavenging DNA-dam-aging reactive oxygen species. However, the detailed mech-anism of the action of ascorbic acid on genetic DNA is still unclear. We examined the effect of ascorbic acid on the higher-order structure of DNA through real-time observa-tion by fluorescence microscopy. We found that ascorbic acid generates a pearling structure in single giant DNA molecules, with elongated and compact regions coexisting along a molecular chain. ...

6p tumor12 20-04-2013 32 5   Download