3 edition of Photooxidation of ascorbate as a substitute for oxygen production by illuminated chloroplasts found in the catalog.
Photooxidation of ascorbate as a substitute for oxygen production by illuminated chloroplasts
Waldo S. Zaugg
|Other titles||Ascorbate as a substitute for oxygen production by illuminated chloroplasts.|
|Statement||by Waldo S. Zaugg.|
|LC Classifications||QK882 .Z38|
|The Physical Object|
|Pagination||iii, 176 leaves :|
|Number of Pages||176|
|LC Control Number||81470673|
A metabolic pathway that consumes oxygen and ATP, releases carbon dioxide, and decreases photosynthetic output. Photorespiration generally occurs on hot, dry, bright days, when stomata close and the oxygen concentration in the leaf exceeds that of carbon dioxide. Follow. Theses/Dissertations from |nI.|pA calorimetric study of the heat of ionization of water at 10 and 40°C, and,|nII.|pA calorimetric determination of the heat of reaction of tris (hydroxymethyl) aminomethane (tham) with hydrochloric acid in aqueous solution at 10, 25, and 40°C, Griffith Lyn Kimball. The purification and characterization of cytochrome b₅ from porcine kidney, M.
The cytochromes hold an oxygen molecule very tightly between the iron and copper ions until the oxygen is completely reduced. The reduced oxygen then picks up two hydrogen ions from the surrounding medium to make water (H 2 O). The removal of the hydrogen ions from the system contributes to the ion gradient used in the process of chemiosmosis. Finally in the presence of oxygen, ATP is formed, providing energy for many cellular functions. However, some electrons can “escape” the electron transport chain and combine with oxygen to form a very unstable form of oxygen called a superoxide radical (O 2 •-). The superoxide radical is one of the reactive oxygen species (ROS).
This banner text can have markup.. web; books; video; audio; software; images; Toggle navigation. Oxygen, Glucose, Ascorbate ©Riordan Clinic Riordan Clinic IVC Academy. C Glucose e-O:Oe-O2 ©Riordan Clinic O2 e-O:Oe-©Riordan Clinic Life = Electron Flow ©Riordan Clinic an electron.
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Zaugg, Waldo S., "Photooxidation of ascorbate as a substitute for oxygen production by illuminated chloroplasts" (). Theses and Dissertations. Date Submitted. Document Type. Author: Waldo S.
Zaugg. Singlet Oxygen reacts with ascorbate to produce H 2 O 2 with a stoichiometry. These plots show the real-time, simultaneous measurements of oxygen consumption (1) and hydrogen peroxide production (2) with ascorbate (1 mM) and Photofrin® ( μg mL-1) in metal-free phosphate buffer, pH Visible light (hν; J m-2 s-1) initiated oxygen consumption and production of H 2 O by: Vitamin E is considered a major antioxidant in biomembranes, but little evidence exists for this function in plants under photooxidative stress.
Leaf discs of two vitamin E mutants, a tocopherol cyclase mutant (vte1) and a homogentisate phytyl transferase mutant (vte2), were exposed to high light stress at low temperature, which resulted in bleaching and lipid by: The present study introduces metabolic modeling as a new tool to analyze the network of redox reactions composing the superoxide dismutase-ascorbate (Asc)-glutathione (GSH) cycle.
Based on previously determined concentrations of antioxidants and defense enzymes in chloroplasts, kinetic properties of antioxidative enzymes, and nonenzymatic rate constants of antioxidants with reactive oxygen.
Importantly, [PS]I photoinhibition was largely alleviated in the presence of methyl viologen, which stimulates the production of reactive oxygen species ([ROS]) at the stromal region by accepting electrons from [PS]I, even under the conditions where CuZn-superoxide dismutase and ascorbate peroxidase activities were inactivated by by: Ferrocytochrome c photooxidation by molecular oxygen with detergent-treated chloroplasts also is markedly stimulated by plastocyanin (63, 70).
Photooxidation of TMPD (with excess ascorbate) coupled to NADP photoreduction is not accompanied by ATP formation (81, 82), an indication that it acts beyond the ATP site. Some of the electron donor systems for photosystem II have been shown to be coupled to ATP formation, 9'39 Ascorbate photooxidation (i.e., ascorbate as donor and oxygen as acceptor via a quinone) is stimu- lated by the phosphorylating system and by an uncoupler as is the nor.
generation of superoxide in the autoxidation of ascorbate and glutathione. oxygen radicals in chemistry and biology: proceedings, 3. suppresion of lipid peroxidation by quercetin and its glycosides in illuminated spinach chloroplasts; efficiency of singlet oxygen production from the 02 quenching of the excited singlet and triplet states.
In these redox reactions of oxygen, the electrons generated by the photooxidation of H 2 O in PS II flow to O 2 in PS I of thylakoid membranes to H 2 O, which is referred to as the water-water cycle. Here, the operation of the water-water cycle in algae is reviewed and the characteristics of the scavenging enzymes of active oxygen are summarized.
Illuminated chloroplasts form H2O2 by reduction of molecular oxygen in the Hill reaction. Possible roles of this reaction in plant physiology are discussed Chloroplasts activate an antioxidant network to reduce damage by singlet oxygen and superoxide anions: these mechanisms involve (1) direct scavenging by carotenoids and (2) enzymatic detoxification of.
mediated by SOD and ascorbate peroxidase (Sano and Asada, ; Gomez et al., ). NOR, and hence N 2 O production, is thought to have preceded COX, and oxygen reduction, on the evolutionary timescale, consistent with the dramatic rise of oxygen in the Earth's atmosphere around.
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Audio. An illustration of a " floppy disk. Software. An illustration of two photographs. Images. An illustration of a heart shape Donate. An illustration of text ellipses. C) The dissolved oxygen in the flask with algae will be higher in the light, but the same in the dark.
D) The dissolved oxygen in the flask with algae will be higher in the light, but lower in the dark. E) The dissolved oxygen in the flask with algae will not be different from the control flask at any time. In mature chloroplasts, PQH2 can be reoxidized by Cyt b 6 f complex; however, in cells without mature chloroplasts (early in leaf development), PTox replaces this activity, reoxidizing PQH2 using O 2 as an electron acceptor (Josse et al.
Carol and KuntzAluru and Rodermel ; see Fig. Carotenoids, in addition to their light. Vitamin E is considered a major antioxidant in biomembranes, but little evidence exists for this function in plants under photooxidative stress.
Leaf discs of two vitamin E mutants, a tocopherol cyclase mutant (vte1) and a homogentisate phytyl transferase mutant (vte2), were exposed to high light stress at low temperature, which resulted in bleaching and lipid photodestruction. However.
Singlet oxygen (1O2) refers to the lowest excited electronic state of molecular oxygen. It easily oxidizes biological molecules and, therefore, is cytotoxic.
In plant cells, 1O2 is formed mostly in the light in thylakoid membranes by reaction centers of photosystem II. In high concentrations, 1O2 destroys membranes, proteins and DNA, inhibits protein synthesis in chloroplasts leading to.
Several reactive oxygen species (ROS) are continuously produced in plants as byproducts of aerobic metabolism. Chloroplasts are a major site of ROS generation in plants. Many environmental changes such as light, temperature, drought, pathogens or nutrient stresses affect the efficiency of photosynthesis and result in ROS production.
The inhibition increases with oxygen concentration and is about 30% in an atmosphere of 21% O 2 and % Co. Undoubtedly, therefore, oxygen in normal air exerts a strong inhibitory effect on photosynthetic Co 2 fixation of land plants under natural conditions.
The inhibitory effect of oxygen is rapidly produced and fully reversible. Vitamin E Deficiency Increases Photooxidative Stress in Leaf Discs Exposed to Short-Term High Light Stress.
Arabidopsis leaf discs, floating on water at 10°C, were exposed to a strong white light with a photon flux density (PFD) of μmol photons m −2 s − treatment caused a rapid inhibition of PSII photochemistry, with the variable-to-maximal chlorophyll fluorescence ratio (Fv.
Aerobic cellular respiration is the process by which cells use oxygen to help them convert glucose into energy. This type of respiration occurs in three steps: glycolysis; the Krebs cycle; and electron transport phosphorylation. Oxygen is necessary for complete oxidation of glucose.Cellular respiration begins when electrons are transferred from NADH and FADH 2 —made in glycolysis, the transition reaction, and the Krebs cycle—through a series of chemical reactions to a final inorganic electron acceptor (either oxygen in aerobic respiration or non-oxygen inorganic molecules in anaerobic respiration).
These electron.suppresion of lipid peroxidation by quercetin and its glycosides in illuminated spinach chloroplasts takahama, umeo pages efficiency of singlet oxygen production from the 02 quenching of the excited singlet and triplet states of rubrene.
menadione mediated photooxidation of purine and pyrimidine 2'-deoxyribonucleosides.