Oxygen species nature

Nishida, M., Maruyama, Y., Tanaka, R., Kontani, K., Nagao, T., and Kurose, H.G. 2000. Alpha and G alpha(o) are target proteins of reactive oxygen species. Nature 408 492-495. 

Ushio-Fukai M, Nakamura Y (2008) Reactive oxygen species and angiogenesis NADPH oxidase as target for cancer therapy. Cancer Lett 266 37-52 Valentin A, Rosati M, Patenaude DJ, Hatzakis A, Kostrikis LG, Lazanas M (2002) Persistent HIV-1 infection of natural killer cells in patients receiving highly active antiretroviral therapy. Proc Natl Acad Sci U S A 99(10) 7015-7020... 

In the last few decades, several epidemiological studies have shown that a dietary intake of foods rich in natural antioxidants correlates with reduced risk of coronary heart disease particularly, a negative association between consumption of polyphenol-rich foods and cardiovascular diseases has been demonstrated. This association has been partially explained on the basis of the fact that polyphenols interrupt lipid peroxidation induced by reactive oxygen species (ROS). A large body of studies has shown that oxidative modification of the low-density fraction of lipoprotein (LDL) is implicated... 

LIN J K s, LEE F, HUANG Y T, LiN-SHiAU s Y (1995) Signal transduction and oncogene expression mediated by reactive oxygen species. In Proceedings of the International Symposium on Natural Antioxidants - Molecular Mechanisms and Health Effects. Eds Packer, L, Traber, M G, Xin, W Champaign, I L, USA AOCS Press, 303-19. 

Wende R, F-H Bernhardt, K Pfleger (1989) Substrate-modulated reactions of putidamonooxin the nature of the active oxygen species formed and its reaction mechanism. Eur J Biochem 81 189-197. 

In order to have more infoimation on the nature of the oxygen species active in partial and total oxidation we investigated the interaction of the hydrocarbons with the pre-oxidized surfaces of oxides where different types of surface oxygen species are formed. In particular we investigated p-type semiconductors like chromia, chromites and cobalt oxide C03O4. Moreover, we studied n-type metal oxides like FezOs, metal ferrites and CuObased catalysts. 

It is observed that higher potential values for the adatom redox process are correlated with a lower energy of the M—O bond, i.e., lower (less negative) enthalpy of formation of the adatom oxygenated species. In this regard, the discrepant behavior of Ge-Pt(lOO) may be related to the dilute nature of this adlayer, with a maximum coverage of only 0.25. 

In addition to the QM structure of the natural terpene QMs, the reactive oxygen species (ROS) may also play a significant role in the observed biological activities. In the synthesis of taxodione and taxodone, QMs were formed from the catechol precursors through the spontaneous oxidation in the presence of silica gel.7, 8,49-51... 

A PP sample after ozonization in the presence of UV-irradiation becomes brittle after 8 hrs of exposure, whereas the same effect in ozone is noticeable after 50-60 hours.Degradation of polymer chain occurs as a result of decomposition of peroxy radicals. The oxidation rapidly reaches saturation, suggesting the surface nature of ozone and atomic oxygen against of PP as a consequence of limited diffusion of both oxygen species into the polymer. Ozone reacts with PP mainly on the surface since the reaction rate and the concentration of intermediate peroxy radicals are proportional to the surface area and not the weight of the polymer. It has been found that polyethylene is attacked only to a depth of 5-7 microns (45). 

That the oxidative burst is directly involved in the chemical defense of these algae is clear. This reaction can be inhibited by diphenyleneiodonium, a suicide inhibitor of NADPH-oxidase which suppresses both the production of reactive oxygen species and the natural resistance to epiphytic bacteria. In addition a role in the defense against endophytes was indicated, since pre-treatment with oligomeric guluronates resulted in decreased infection of L. digitata with the pathogen Laminariocolax tomentosoides [141]. 

Mixed chalcogen derivatives of phosphinic and phosphoric acids are also known, the most studied being the mixed sulfur-oxygen species. Thiophos-phoric acids exist in two different isomeric forms - the thiono form (18a) and the thiolo form (18b). The equilibria usually sits somewhere in between these two species, being dependent upon the nature of the R substituents, the solvent and in some cases the concentration. Thiophosphinic acids are also able to interconvert between the thiono (19a) and thiolo (19b) tautomers, although the equilibrium position usually sits well on the side of the thiono tautomer.1... 

Historically, leukocyte NADPH oxidase was the first discovered enzyme of this type the existence of this enzyme in neutrophils was reported in 1962-1966 [59-61]. (As the evidence of superoxide production in biological systems has been obtained several years later, at that time the nature of oxygen species produced by leukocytes was of course unknown.) And only about 10 years later, Babior et al. [62] have shown that the activation of human neutrophils resulted in the production of superoxide. The structure of leukocyte NADPH has been widely discussed and well-established [57]. Superoxide production catalyzed by NADPH oxidase is described by Reaction (5) ... 

Colquhoun and Schumacher [98] have shown that y-linolcnic acid and eicosapentaenoic acid, which inhibit Walker tumor growth in vivo, decreased proliferation and apoptotic index in these cells. Development of apoptosis was characterized by the enhancement of the formation of reactive oxygen species and products of lipid peroxidation and was accompanied by a decrease in the activities of mitochondrial complexes I, III, and IV, and the release of cytochrome c and caspase 3-like activation of DNA fragmentation. Earlier, a similar apoptotic mechanism of antitumor activity has been shown for the flavonoid quercetin [99], Kamp et al. [100] suggested that the asbestos-induced apoptosis in alveolar epithelial cells was mediated by iron-derived oxygen species, although authors did not hypothesize about the nature of these species (hydroxyl radicals, hydrogen peroxide, or iron complexes ). 

Oxidative stress induced by reactive oxygen species is described for many other brain disorders of inflammatory and noninflammatory nature. Some examples of such disorders are given below. Quick and Dugan [326] demonstrated superoxide-mediated damage of neurons... 

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