Effect of alkylated and intercalated DNA on the generation of superoxide anion by riboflavin

1988 ◽  
Vol 8 (5) ◽  
pp. 485-492 ◽  
Author(s):  
Imrana Naseem ◽  
Maqbool Ahmad ◽  
S. M. Hadi
Keyword(s):  
Ethidium Bromide ◽  
Superoxide Anion ◽  
Active Oxygen Species ◽  
Active Oxygen ◽  
Fluorescent Light ◽  
Oxygen Species ◽  
Base Pairs ◽  
Double Stranded Dna ◽  
Purines And Pyrimidines ◽  
Stimulation Of

Superoxide anion (O2.-) was photogenerated upon illumination of riboflavin in fluorescent light. The rate of O2.- formation was stimulated by double stranded DNA but not by denatured DNA or RNA. Depurinated DNA, which was predominantly depleted in guanine residues, did not exhibit the stimulatory effect, indicating an interaction of riboflavin, or active oxygen species derived from it, with guanine bases. Also, the stimulation of O2.- photogeneration was not observed with ethidium bromide but was seen with proflavin-intercalated DNA. Since ethidium bromide intercalates preferentially between purines and pyrimidines, and proflavin prefers dA-dT rich sites, these results were interpreted to suggest that the interaction of riboflavin with DNA is mainly with GC or CG base pairs.

Stimulation of poly(ADP-ribose) synthesis by free radicals in C3H10T1/2 cells: relationship with NAD metabolism and DNA breakage

1990 ◽  
Vol 68 (3) ◽  
pp. 602-608 ◽  
Author(s):  
Dominique Lautier ◽  
Danièle Poirier ◽  
Annie Boudreau ◽  
Moulay A. Alaoui Jamali ◽  
André Castonguay ◽  
...  
Keyword(s):  
Free Radicals ◽  
Active Oxygen Species ◽  
Accurate Determination ◽  
Active Oxygen ◽  
Single Strand ◽  
Oxygen Species ◽  
Strand Breaks ◽  
Dna Breakage ◽  
Single Strand Breaks ◽  
Stimulation Of

We have studied the effect of H2O2 and O2− produced by xanthine and xanthine oxidase on NAD catabolism, poly(ADP-ribose) synthesis, and production of DNA single-strand breaks in C3H10T1/2 cells. The results show a correlation between the induction of DNA single-strand breaks, the decrease of NAD pool, and the accumulation of polymer. New techniques, based on affinity chromatography and reversed-phase high pressure liquid chromatography, have allowed an accurate determination of polymer contents and showed a 20-fold stimulation of polymer biosynthesis induced by active oxygen species. Inhibition experiments performed with 3-aminobenzamide have shown that the decrease in NAD levels after exposure of cells to active oxygen species was caused by stimulation of poly(ADP-ribosyl)ation and of another cellular process.Key words: poly(ADP-ribose), free radicals, C3H10T1/2 cells, DNA breakage, NAD catabolism.

scholarly journals Studies on the mechanism of mutagenicity and genotoxicity induced by dihydralazine.

1995 ◽  
Vol 42 (3) ◽  
pp. 291-295 ◽  
Author(s):  
B Chłopkiewicz ◽  
A Ejchart ◽  
J Marczewska
Keyword(s):  
Superoxide Anion ◽  
Reduction Method ◽  
Active Oxygen Species ◽  
Active Oxygen ◽  
Oxygen Species ◽  
Oxygen Scavengers ◽  
E Coli ◽  
Sos Chromotest ◽  
Tetrazolium Reduction

Dihydralazine was found to be mutagenic towards S. typhimurium TA1537, TA97, TA1538 and TA98 and genotoxic towards E. coli PQ37. Using the nitro blue tetrazolium reduction method we have found that dihydralazine can generate active oxygen species. The possible role of active oxygen species in mutagenicity (Ames test) and genotoxicity (SOS Chromotest) of dihydralazine was studied by testing the influence of the different active oxygen species scavengers on these two processes. Of the active oxygen scavengers tested, only superoxide dismutase suppressed partially the mutagenic and genotoxic activity of dihydralazine. This result seems to indicate that superoxide anion play a role in these two biological events.

Post-Doping of ZnO with Cu and its Effect on their Photocatalytic Production of Active Oxygen Species

2011 ◽  
Vol 197-198 ◽  
pp. 853-856
Author(s):  
Xiao Ling Xu ◽  
Dan Chen ◽  
Xing Duan ◽  
Zhi Gang Yi ◽  
Zuo Wan Zhou
Keyword(s):  
Superoxide Anion ◽  
Diffuse Reflectance ◽  
Dopant Concentration ◽  
Active Oxygen Species ◽  
Active Oxygen ◽  
Oxygen Species ◽  
Energy Band Gap ◽  
Cu Doping ◽  
Zinc Oxides ◽  
Recombination Centers

Cu doping zinc oxides (ZnOs) were prepared by a post doping process with CuCl2 at high temperature. With the increase of the dopant loading, the lattice constant c decreased firstly and then increased, which indicated that the doped Cu atoms substituted for Zn atoms at lower loading and extra dopant of the Cu atoms existed as interstitial atoms. UV-Vis diffuse reflectance spectra (UV-DRS) illustrated that the energy band gap was effectively narrowed after Cu doping. The photocatalytic production of hydroxyl radical (•OH) and superoxide anion (O2-) were determined by terephthalic acid with fluorescence spectrophotometer and nitroblue tetrazolium with UV-Vis spectrophotometer respectively, and the results showed that both the photocatalytic production of •OH and O2- were deceased with the increase of the dopant concentration, which indicated that the recombination centers were formed in the samples.

The Effect of Active Oxygen Species on the Cornea

1990 ◽  
Vol 48 (3) ◽  
pp. 242-243
Author(s):  
H. Nguyen ◽  
R. Carubelli ◽  
K.V. Chace ◽  
S.A. Graham ◽  
R. E. Nordquist
Keyword(s):  
Hydrogen Peroxide ◽  
Glucose Oxidase ◽  
Superoxide Anion ◽  
Tissue Injury ◽  
Vitamin A Deficiency ◽  
Active Oxygen Species ◽  
Active Oxygen ◽  
Oxygen Species ◽  
Corneal Ulceration ◽  
Corneal Melting

Corneal ulceration (“corneal melting”) can occur following various types of insults to the eye, e.g., alkaline or thermal burns, ocular laceration, rheumatoid arthritis, eye infections and vitamin A deficiency. A common link in this multiplicity of etiologic factors is the probable participation of active oxygen species (i.e., hydrogen peroxide, singlet oxygen and free radicals such as superoxide anion and hydroxyl radical). These compounds could play an important role in the pathogenesis of corneal melting since they have been implicated in numerous types of tissue injury. Therefore, we decided to investigate in rabbit cornea the effects of hydrogen peroxide (H2O2) and superoxide anion () generated in situ. Oxidation of endogenous corneal glucose by glucose oxidase was utilized for the generation of H2O2. A cationic preparation of glucose oxidase Aspergillus niger was obtained by amidation of its free carboxylic groups. This modification enhances retention of the enzyme through ionic interaction with polyanionic corneal proteoglycans. Intrastromal injections of 30-60 ug of this enzyme cause corneal ulceration in the rabbit.

scholarly journals Induction of benzo[a]pyrene Mono-oxygenase in liver cell culture by the photochemical generation of active oxygen species. Evidence for the involvement of singlet oxygen and the formation of a stable inducing intermediate

1976 ◽  
Vol 158 (1) ◽  
pp. 109-117 ◽  
Author(s):  
A J Paine
Keyword(s):  
Singlet Oxygen ◽  
Culture Medium ◽  
Enzyme System ◽  
Active Oxygen Species ◽  
Active Oxygen ◽  
Oxygen Species ◽  
Photochemical Generation ◽  
Single Oxygen ◽  
Cytochrome P 450 ◽  
Stimulation Of

1. The photochemical generation of excited states of oxygen in liver cell culture by the mild ilumination of culture medium containing riboflavin, results in stimulation of benzo[a]pyrene 3-mono-oxygenase, a cytochrome P-450-linked mono-oxygenase. 2. The same large increase in mono-oxygenase activity was found when medium containing riboflavin was illuminated in the absence of cells and then stored in the dark for 24h before contact with the cells. From this it may be inferred that stimulation is due to the formation of a stable inducer in the culture medium. Further experiments indicate that the stable inducer is due to the photo-oxidation of an amino acid. 3. Evidence that singlet oxygen is responsible for initiating the stimulation of the mono-oxygenase is based on the use of molecules that scavenge particular active oxygen species. Of all the scavengers tested, only those that scavenge single oxygen inhibited the stimulation. 4. A hypothesis is developed to relate the stimulation of the mono-oxygenase by singlet oxygen in cultured cells to the regulation of the cytochrome P-450 enzyme system in vivo. It is suggested that single oxygen generation within cells may be a common factor linking the many structurally diverse inducers of the enzyme system.

Characterization and functional properties of new everbearing strawberry (Fragaria x ananasa Duch.) cultivar, ‘Summertiara’ berries

2014 ◽  
Vol 4 (1) ◽  
pp. 1 ◽  
Author(s):  
Takeshi Nagai ◽  
Misuzu Tamai ◽  
Masato Sato ◽  
Yasuhiro Tanoue ◽  
Norihisa Kai ◽  
...  
Keyword(s):  
Vitamin C ◽  
Sensory Evaluation ◽  
Functional Properties ◽  
Active Oxygen Species ◽  
Active Oxygen ◽  
Antihypertensive Activity ◽  
Oxygen Species ◽  
Total Anthocyanins ◽  
Strawberry Cultivar ◽  
The Stability

Background: In recent years, a new everbearing strawberry cultivar, ‘Summertiara’ was cultivated to supply the strawberries in pre-harvest season from July to October in Japan. For highly research and development of processing of this cultivar, ‘Summertiara’ berries, the objective of this study was to characterize these berries, with relation to chemical parameters, total phenols, total flavonoids, total vitamin C, and total anthocyanins, and was to investigate the solubility and the stability of anthocyanins from the berries. Moreover, the functional properties such as antioxidative activity, active oxygen species scavenging activity, and antihypertensive activity were also evaluated.Methods: Chemical analysis, colour measurement, and sensory evaluation of new everbearing strawberry cultivar, ‘Summertiara’ berries were performed. Next, the solubility of anthocyanins from the berries and stability of these against pH, temperature, and an incandescent lighting were investigated. Moreover, functional properties of the extracts prepared from berries were elucidated using 5 different methods.Results: The contents of water, proteins, lipids, carbohydrates, and ash were the same as those of other cultivar berries. The sugar-acid ratio in the berries was low; these were acidulous. By sensory evaluation, the main factors were vivid red colour, aroma, and acidity. The berries were rich in phenols, flavonoids, vitamin C, and anthocyanins. The anthocyanins of the berries became unstable by heat treatment and light exposures such as visible rays. On the other hand, the extracts prepared from the berries showed the functionalities such as antioxidant activity, active oxygen species scavenging activities, and antihypertensive activity.  Conclusions: The strawberry cultivar, ‘Summertiara’ berries were the most suitable for processing ingredient of strawberry-derived products with superior health promoting functionalities.Keywords: Summertiara, everbearing strawberry cultivar, characterization, sensory evaluation, color and storage, functional property

Identifying the Active Oxygen Species in SnO2 Based Gas Sensing Materials: An Operando IR Spectrsocopy Study

2015 ◽  
Vol 119 (21) ◽  
pp. 11792-11799 ◽  
Author(s):  
David Degler ◽  
Susanne Wicker ◽  
Udo Weimar ◽  
Nicolae Barsan
Keyword(s):  
Gas Sensing ◽  
Active Oxygen Species ◽  
Active Oxygen ◽  
Oxygen Species ◽  
Ir Spectrsocopy
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