Sami Ahmad

Oxidative Stress and Antioxidant Defenses in Biology

• Broschiertes Buch

Produktbeschreibung

The ground-state of molecular oxygen, O , is essential to many 2 indispensible metabolic processes of all aerobic life forms ranging from prokaryotes, protists, plants, and fungi to animals. Research by mammalian toxicologists and clinicians has unravelled persua sive evidence that O dependence imposes universal toxicity to all 2 aerobic life processes. The basis of this paradox is that one-electron reduction of O2 generates the superoxide anion free radical, 0;-, from numerous biological sources; for example, redox-active autoxidizable molecules such as catecholamines, oxidoreductases, and subcellular organelles such as mitochondria, endoplasmic reti'C ulum (microsomes), nuclei, and chloroplasts. Oxygen is also acti vated in biologically relevant photosensitizing reactions to highly re active singlet oxygen, 10 , 2 In all biological systems, 0;- undergoes further reduction to H 0 2 2 via Fenton reaction to the hydroxyl radical, ·OH. These, and some other forms of activated O , constitute reactive oxygen species (ROS) 2 and/or metabolites (ROM). Both 'OH and 10 are the most reactive 2 forms of ROS known and among their deleterious reactions are ox idation of proteins, DNA, steroidal compounds, and peroxidation of the cell membrane's unsaturated lipids to form unstable hydro peroxides. Their many breakdown products include malondialde hyde and hydroxynonenals that are themselves highly reactive and threaten cellular integrity and function. More importantly, they de compose to free radicals that can continue to propagate the vicious lipid peroxidation chain reaction. This is the so-called endogenous oxidative stress with which all aerobic organisms must cope.

Produktdetails

• Verlag: Springer / Springer US / Springer, Berlin
• Artikelnr. des Verlages: 978-1-4615-9691-2
• Softcover reprint of the original 1st ed. 1995
• Seitenzahl: 480
• Erscheinungstermin: 5. Februar 2012
• Englisch
• Abmessung: 229mm x 152mm x 26mm
• Gewicht: 689g
• ISBN-13: 9781461596912
• ISBN-10: 1461596912
• Artikelnr.: 39491345

Inhaltsangabe

1 Mechanisms of oxygen activation and reactive oxygen species detoxification.- Chemistry of reactive oxygen species.- Biological sources of free radicals.- The reactivity of free radicals with non-enzymic small molecular antioxidants.- Primary antioxidant defenses.- Secondary antioxidant defenses.- Oxidants and antioxidants.- Summary.- References.- 2 Pathophysiology and reactive oxygen metabolites.- Ischemia and repufusion injury.- Inflammatory bowel disease.- Arthritis.- Central nervous system injury.- Acute renal failure.- Sickle cell anemia.- Cancer.- Summary.- References.- 3 Free radical mechanisms of oxidative modification of low density lipoprotein (or the rancidity of body fat).- Oxidative modification of low density lipoprotein and its relevance to atherogenesis.- Effect of supplementation with antioxidant.- Inhibition of LDL oxidation by phenolic antioxidants.- Summary.- References.- 4 Synthetic pro-oxidants: drugs, pesticides and other environmental pollutants.- Halogenated alkanes and alkenes.- Dioxin and its bioisosteres.- Halogenated cyclic pesticides.- Phorbol esters.- Paraquat and diquat.- Quinones.- Quinolones.- Transition metals and cation complexes.- Miscellaneous inducers of oxidative stress.- Summary and conclusions.- References.- 5 Metabolic detoxification of plant pro-oxidants.- Detoxification of photosensitizers.- Metabolism of redox-active prooxidants.- Summary and conclusions.- References.- 6 Antioxidant mechanisms of secondary natural products.- Kinetics of antioxidation.- Antioxidants as reducing agents.- Antioxidants as radical quenchers.- Antioxidants as singlet oxygen quenchers.- Antioxidants as metal Ion complexing agents.- Synergistic effects.- Summary.- References.- 7 Antioxidant mechanisms of enzymes and proteins.- 7.1 Introduction.- 8Antioxidant defenses of Escherichia coli and Salmonella typhimurium.- Direct defenses against oxidative stress.- Indirect defenses against oxidative stress.- Summary.- References.- 9 Antioxidant defenses of plants and fungi.- Sources of activated forms of oxygen.- Antioxidant defenses in chloroplasts.- Antioxidant defenses in nitrogen fixation.- The role of catalase.- Stress and antioxidant defenses.- Miscellaneous antioxidants in plants.- Beneficial uses of active oxygen in plants.- Antioxidant defenses of fungi.- Summary.- References.- 10 Antioxidant defenses of vertebrates and invertebrates.- Avoidance of oxidative stress.- Enzymatic removal of ROS.- Prevention or interception of free radical processes.- Repair processes.- Summary and final comments.- References.- 11 Genetic regulation of antioxidant defenses in Escherichia coli and Salmonella typhimurium.- Response to oxidative stress.- Response to H2O2: The peroxide stimulon and the oxyR regulon.- Response to O2·?: The superoxide stimulon and the soxRS regulon.- Response to starvation/stationary phase stimulon and the katF regulon.- Multi-layered regulation: sodA gene.- Summary.- References.

Rezensionen

...on reading the unusual melange of contributors and specific topics covered Oxidative Stress and Antioxidant Defences in Biology, this feeling [deja vu] is soon replaced by one of enthusiastic anticipation - and with the majority of chapters one is not diappointed. - The Biochemist