scholarly journals Formation of α-tocopherol hydroperoxide and α-tocopheroxyl radical: relevance for photooxidative stress in Arabidopsis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Aditya Kumar ◽  
Ankush Prasad ◽  
Pavel Pospíšil
Keyword(s):  
Singlet Oxygen ◽  
Peroxyl Radical ◽  
Higher Plants ◽  
Xylenol Orange ◽  
Hydrogen Abstraction ◽  
Lipid Hydroperoxide ◽  
Antioxidant Defense System ◽  
High Light ◽  
Oxidation Products ◽  
Tocopheroxyl Radical

AbstractTocopherols, lipid-soluble antioxidants play a crucial role in the antioxidant defense system in higher plants. The antioxidant function of α-tocopherol has been widely studied; however, experimental data on the formation of its oxidation products is missing. In this study, we attempt to provide spectroscopic evidence on the detection of oxidation products of α-tocopherol formed by its interaction with singlet oxygen and lipid peroxyl radical. Singlet oxygen was formed using photosensitizer rose bengal and thylakoid membranes isolated from Arabidopsis thaliana. Singlet oxygen reacts with polyunsaturated fatty acid forming lipid hydroperoxide which is oxidized by ferric iron to lipid peroxyl radical. The addition of singlet oxygen to double bond carbon on the chromanol head of α-tocopherol forms α-tocopherol hydroperoxide detected using fluorescent probe swallow-tailed perylene derivative. The decomposition of α-tocopherol hydroperoxide forms α-tocopherol quinone. The hydrogen abstraction from α-tocopherol by lipid peroxyl radical forms α-tocopheroxyl radical detected by electron paramagnetic resonance. Quantification of lipid and protein hydroperoxide from the wild type and tocopherol deficient (vte1) mutant Arabidopsis leaves using a colorimetric ferrous oxidation-xylenol orange assay reveals that α-tocopherol prevents formation of both lipid and protein hydroperoxides at high light. Identification of oxidation products of α-tocopherol might contribute to a better understanding of the protective role of α-tocopherol in the prevention of oxidative damage in higher plants at high light.

Lipid Hydroperoxide Determination in Dark Chicken Meat through a Ferrous Oxidation−Xylenol Orange Method

2000 ◽  
Vol 48 (9) ◽  
pp. 4136-4143 ◽  
Author(s):  
Anna Grau ◽  
Rafael Codony ◽  
Magda Rafecas ◽  
Ana C. Barroeta ◽  
Francesc Guardiola
Keyword(s):  
Xylenol Orange ◽  
Lipid Hydroperoxide ◽  
Chicken Meat ◽  
Ferrous Oxidation

Lipid hydroperoxide measurement by oxidation of Fe2+ in the presence of xylenol orange. Comparison with the TBA assay and an iodometric method

Lipids ◽  
1991 ◽  
Vol 26 (10) ◽  
pp. 853-856 ◽  
Author(s):  
Zhen-Yue Jiang ◽  
Alison C. S. Woollard ◽  
Simon P. Wolff
Keyword(s):  
Xylenol Orange ◽  
Lipid Hydroperoxide

scholarly journals Occurrence of neoxanthin and lutein epoxide cycle in parasitic Cuscuta species.

2008 ◽  
Vol 55 (1) ◽  
pp. 183-190 ◽  
Author(s):  
Jerzy Kruk ◽  
Renata Szymańska
Keyword(s):  
Substrate Specificity ◽  
Xanthophyll Cycle ◽  
Higher Plants ◽  
Light Stress ◽  
High Light ◽  
Light Conditions ◽  
Strong Light ◽  
Zeaxanthin Epoxidase ◽  
Typical Response ◽  
Cuscuta Species

In the present study, xanthophyll composition of eight parasitic Cuscuta species under different light conditions was investigated. Neoxanthin was not detected in four of the eight species examined, while in others it occurred at the level of several percent of total xanthophylls. In C. gronovii and C. lupuliformis it was additionally found that the neoxanthin content was considerably stimulated by strong light. In dark-adapted plants, lutein epoxide level amounted to 10-22% of total xanthophylls in only three species, the highest being for C. lupuliformis, while in others it was below 3%, indicating that the lutein epoxide cycle is limited to only certain Cuscuta species. The obtained data also indicate that the presence of the lutein epoxide cycle and of neoxanthin is independent and variable among the Cuscuta species. The xanthophyll cycle carotenoids violaxanthin, antheraxanthin and zeaxanthin were identified in all the examined species and occurred at the level found in other higher plants. The xanthophyll and lutein epoxide cycle pigments showed typical response to high light stress. The obtained results also suggest that the ability of higher plants to synthesize lutein epoxide probably does not depend on the substrate specificity of zeaxanthin epoxidase but on the availability of lutein for the enzyme.

scholarly journals Chloroplast retrograde signal regulates flowering

2016 ◽  
Vol 113 (38) ◽  
pp. 10708-10713 ◽  
Author(s):  
Peiqiang Feng ◽  
Hailong Guo ◽  
Wei Chi ◽  
Xin Chai ◽  
Xuwu Sun ◽  
...  
Keyword(s):  
Transcriptional Repression ◽  
Molecular Basis ◽  
Light Quality ◽  
Higher Plants ◽  
High Light ◽  
Retrograde Signaling ◽  
Adaptive Responses ◽  
Detailed Understanding ◽  
Transcriptional Changes ◽  
Retrograde Signal

Light is a major environmental factor regulating flowering time, thus ensuring reproductive success of higher plants. In contrast to our detailed understanding of light quality and photoperiod mechanisms involved, the molecular basis underlying high light-promoted flowering remains elusive. Here we show that, in Arabidopsis, a chloroplast-derived signal is critical for high light-regulated flowering mediated by the FLOWERING LOCUS C (FLC). We also demonstrate that PTM, a PHD transcription factor involved in chloroplast retrograde signaling, perceives such a signal and mediates transcriptional repression of FLC through recruitment of FVE, a component of the histone deacetylase complex. Thus, our data suggest that chloroplasts function as essential sensors of high light to regulate flowering and adaptive responses by triggering nuclear transcriptional changes at the chromatin level.

Importance of Singlet Oxygen in the Degradation of Rubbers and Plastics

1974 ◽  
Vol 47 (4) ◽  
pp. 991-1004 ◽  
Author(s):  
D. J. Carlsson ◽  
D. M. Wiles
Keyword(s):  
Singlet Oxygen ◽  
Ground State ◽  
Aromatic Amines ◽  
Oxidation Products ◽  
Aromatic Pollutants ◽  
Nickel Chelates ◽  
Light Stability

Abstract Singlet oxygen attack on rubbers and poly(olefins) is likely to be significant in the presence of sensitizing impurities such as oxidation products, polynuclear aromatic pollutants, and many additives. 1O2 attack will yield hydroperoxide groups, and so markedly impair the subsequent heat and light stability of the materials. However stabilizer systems which have already been developed can be expected to protect against the effects of 1O2 by quenching to the relatively inoccuous 2O3 (ground state oxygen). For rubbers the aromatic amines widely employed as antizonants will protect against 1O2 attack, whereas the nickel chelates employed as uv stabilizers will protect poly(olefins).

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