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Encyclopedia > Reactive oxygen species

Reactive oxygen species (ROS) include oxygen ions, free radicals and peroxides both inorganic and organic. They are generally very small molecules and are highly reactive due to the presence of unpaired valence shell electrons. ROSs form as a natural byproduct of the normal metabolism of oxygen and have important roles in cell signaling. However, during times of environmental stress ROS levels can increase dramatically which can result in significant damage to cell structures. This cumulates into a situation known as oxidative stress. Cells are normally able to defend themselves against ROS damage through the use of enzymes such as superoxide dismutases and catalases. Small molecule antioxidants such as Ascorbic acid (vitamin-C),uric acid, and glutathione also play important roles as cellular antioxidants. Similarly, Polyphenol antioxidants assist in preventing ROS damage by scavenging free radicals. In contrast, the antioxidant ability of the extracellular space in relatively less. E.g., the most important plasma antioxidant in humans is probably uric acid. General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... An ion is an atom or group of atoms that normally are electrically neutral and achieve their status as an ion by loss (or addition) of an electron(s). ... For other uses, see radical. ... Peroxide has three distinct meanings: // Main article: hydrogen peroxide In common usage, peroxide is an aqueous solution of hydrogen peroxide (HOOH or H2O2) sold for use as a disinfectant or mild bleach. ... Organic peroxides are organic molecules containing the peroxide functional group ROOR If the R is hydrogen, the compound is called an organic hydroperoxide or a peroxy acid. ... Properties The electron (also called negatron, commonly represented as e−) is a subatomic particle. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... Oxidative stress is a medical term for damage to animal or plant cells (and thereby the organs and tissues composed of those cells) caused by reactive oxygen species, which include (but are not limited to) superoxide, singlet oxygen, peroxynitrite or hydrogen peroxide. ... Neuraminidase ribbon diagram An enzyme (in Greek en = in and zyme = blend) is a protein, or protein complex, that catalyzes a chemical reaction and also controls the 3D orientation of the catalyzed substrates. ... Superoxide dismutase The enzyme superoxide dismutase (SOD, EC 1. ... Catalase (human erythrocyte catalase: PDB 1DGF, EC 1. ... This article deals with the molecular aspects of ascorbic acid. ... This article or section is in need of attention from an expert on the subject. ... Skeletal formula of glutathione 3D model of glutathione Glutathione (GSH), whose IUPAC name is 2-amino-5-{[2-[(carboxymethyl)amino]- 1-(mercaptomethyl)-2-oxoethyl]amino}-5-oxopentanoic acid, is γ-glutamylcysteinylglycine, a tripeptide. ... Molecular structure of flavone, a common polyphenol antioxidant A polyphenol antioxidant is a member of a class of multi-phenolic compounds known for their role in down-regulating free radical formation in mammals . ... This article or section is in need of attention from an expert on the subject. ...


The effects of ROS on cell metabolism have been well documented in a variety of species. These include not only roles in programmed cell death and apoptosis, but also positive effects such as the induction of host defence genes and mobilisation of ion transport systems. This is implicating them more frequently with roles in redox signaling or oxidative signaling. In particular, platelets involved in wound repair and blood homeostasis release ROS to recruit additional platelets to sites of injury. These also provide a link to the adaptive immune system via the recruitment of leukocytes. A cell undergoing apoptosis. ... This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). ... Redox signaling is the concept that free radicals, reactive oxygen species (ROS), and other electronically-activated species act as messengers in biological systems. ... A 250 ml bag of newly collected platelets. ... Superficial bullet wounds In medicine, a wound is type of physical trauma wherein the skin is torn, cut or punctured (an open wound), or where blunt force trauma causes a contusion (a closed wound). ... Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ... Homeostasis is the property of an open system, especially living organisms, to regulate its internal environment to maintain a stable, constant condition, by means of multiple dynamic equilibrium adjustments, controlled by interrelated regulation mechanisms. ... Injury is damage or harm caused to the structure or function of the body caused by an outside agent or force, which may be physical or chemical. ... The immune system protects the body from infection by pathogenic organisms. ... White Blood Cells is also the name of a White Stripes album. ...


Reactive oxygen species are implicated in cellular activity to a variety of inflammatory responses including cardiovascular disease. They may also be involved in hearing impairment via cochlear damage induced by elevated sound levels, ototoxicity of drugs such as cis-platin and in congenital deafness in both animals and humans. Redox signaling is also implicated in mediation of apoptosis or programmed cell death and ischaemic injury. Specific examples include stroke and heart attack. It has been suggested that this article or section be merged with Coronary heart disease. ... Please wikify (format) this article or section as suggested in the Guide to layout and the Manual of Style. ... Cross section of the cochlea. ... Environmental noise can produce irreversible hearing loss Noise health effects, the collection of health consequences of elevated sound levels, constitute one of the most widespread public health threats in industrialized countries. ... Redox signaling is the concept that free radicals, reactive oxygen species (ROS), and other electronically-activated species act as messengers in biological systems. ... A cell undergoing apoptosis. ... In medicine, ischemia (Greek ισχαιμία, isch- is restriction, hema or haema is blood) is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. ... For other articles with similar names, see Stroke (disambiguation). ... A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, totally occluding the artery and preventing blood flow downstream. ...


See also

Oxidative stress is a medical term for damage to animal or plant cells (and thereby the organs and tissues composed of those cells) caused by reactive oxygen species, which include (but are not limited to) superoxide, singlet oxygen, peroxynitrite or hydrogen peroxide. ... Molecular structure of flavone, a common polyphenol antioxidant A polyphenol antioxidant is a member of a class of multi-phenolic compounds known for their role in down-regulating free radical formation in mammals . ... Redox signaling is the concept that free radicals, reactive oxygen species (ROS), and other electronically-activated species act as messengers in biological systems. ... Broadly, melanin is any of the polyacetylene, polyaniline, and polypyrrole blacks and browns or their mixed copolymers. ... Harry B. Demopoulos, MD, is an important pioneer in the medical aspects of Free radicals, especially in the areas of ischaemic injury, the toxicity of anticancer drugs, and in spinal cord injury. ...

References

  • Sen, C.K. (2003) The general case for redox control of wound repair, Wound Repair and Regeneration, 11, 431-438
  • Krötz, F., Sohn, HY., Gloe, T., Zahler, S., Riexinger, T., Schiele, T.M., Becker, B.F., Theisen, K., Klauss, V., Pohl, U. (2002) NAD(P)H oxidase-dependent platelet superoxide anion release increases platelet recruitment, Blood, 100, 917-924
  • Pignatelli, P. Pulcinelli, F.M., Lenti, L., Gazzaniga, P.P., Violi, F. (1998) Hydrogen Peroxide Is Involved in Collagen-Induced Platelet Activation, Blood, 91 (2), 484-490
  • Guzik, T.J., Korbut, R., Adamek-Guzik, T. (2003) Nitric oxide and superoxide in inflammation and immune regulation, Journal of Physiology and Pharmacology, 54 (4), 469-487
  • Free Radicals and Human Disease, a Review

  Results from FactBites:
 
Reactive oxygen species - Wikipedia, the free encyclopedia (453 words)
Reactive oxygen species (ROS) include oxygen ions, free radicals and peroxides both inorganic and organic.
They are generally very small molecules and are highly reactive due to the presence of unpaired valence shell electrons.
Reactive oxygen species are implicated in cellular activity to a variety of inflammatory responses including cardiovascular disease.
Journal of Carcinogenesis | Full text | Reactive oxygen species: role in the development of cancer and various chronic ... (4693 words)
Oxygen derived species such as superoxide radical, hydrogen peroxide, singlet oxygen and hydroxyl radical are well known to be cytotoxic and have been implicated in the etiology of a wide array of human diseases, including cancer.
Reactive oxygen species (ROS) are derived from the metabolism of molecular oxygen [3].
The role of reactive oxygen species in cell growth regulation is complex, being cell specific and dependent upon the form of the oxidant as well as the concentration of the particular reactive oxygen species.
  More results at FactBites »

 
 

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