Reactive 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

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 10 3   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

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

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

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

The peroxidase–oxidase reaction is known to involve react-ive oxygen species as intermediates. These intermediates inactivatemany types of biomolecules, including peroxidase itself. Previously,wehave shown that oscillatorydynamics in the peroxidase–oxidase reaction seem to protect the enzyme frominactivation. It was suggested that this is due to a lower average concentration of reactive oxygen species in the oscillatory state compared to the steady state. Here, we studied the peroxidase–oxidase reaction with either 4-hydroxybenzoic acid or melatonin as cofactors. ...

9p fptmusic 16-04-2013 45 4   Download

Photodynamic treatment (PDT) is an emerging therapeutic procedure for the management of cancer, based on the use of photosensitizers, compounds that generate highly reactive oxygen species (ROS) on irradiation with visible light. The ROS generated may oxidize a variety of bio-molecules within the cell, loaded with a photosensitizer. The high reactivity of these ROS restricts their radius of action to 5–20 nm from the site of their generation.

7p fptmusic 12-04-2013 44 3   Download

Photoactivated riboflavin in the presence of Cu(II) generates reactive oxygen species (ROS) which can hemolyse human red blood cells (RBC). In the present work we examined the effect of sodium azide (NaN3) on RBC in the presence of riboflavin and Cu(II). The addition of NaN3 to the riboflavin-Cu(II) sys-tem enhanced K + loss and hemolysis. The extent of K + loss and hemolysis were time and concentration dependent. Batho-cuproine, a Cu(I)-sequestering agent inhibited the hemolysis completely.

31p fptmusic 11-04-2013 45 3   Download

Oxidative stress and imbalance between free radical generation and detoxi-fication may play a pivotal role in the pathogenesis of Leber’s hereditary optic neuropathy (LHON). Mitochondria, carrying the homoplasmic 11778⁄ND4, 3460⁄ND1 and 14484⁄ND6 mtDNA point mutations associ-ated with LHON, were used to generate osteosarcoma-derived cybrids. Enhanced mitochondrial production of reactive oxygen species has recently been demonstrated in these cybrids [Beretta S, Mattavelli L, Sala G, Trem-olizzo L, Schapira AHV, Martinuzzi A, Carelli V & Ferrarese C (2004) Brain127, 2183–2192]. ...

0p awards 05-04-2013 44 4   Download

Metformin (1,1-dimethylbiguanide) is an antihyperglycae-mic drug used to normalize glucose concentrations in type 2 diabetes. Furthermore, antioxidant benefits have been reported in diabetic patients treated with metformin. This work was aimed at studying the scavenging capacity of this drug against reactive oxygen species (ROS) like Æ OH and O Æ
2 -free radicals. ROS were produced by gamma radio-lysis of water. The irradiated solutions of metformin were analyzed by UV/visible absorption spectrophotometry.

8p awards 05-04-2013 60 1   Download

Three pairs of parental (q + ) and established mitochondrial DNAdepleted (q 0 ) cells, derived frombone, lungandmuscle were used to verify the influence of the nuclear background and the lack of efficient mitochondrial respiratory chain on antioxidant defences and homeostasis of intracellular reactive oxygen species (ROS).

11p awards 05-04-2013 44 4   Download

The retinal pigment epithelium (RPE) is essential for main-tenance of photoreceptors and normally functions under conditions enriched with reactive oxygen species. RPE therefore expresses various defense enzymes against oxida-tive stress, including heme oxygenase-1 (HO-1). HO-1 catalyzes heme breakdown to release iron, carbon monox-ide, and biliverdin, which is reduced to bilirubin, a potent radical scavenger. HO-1 expression is induced by various environmental factors, which has been established as a def-ense mechanism....

9p awards 05-04-2013 41 4   Download