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Article ; Online: COVID-19 and the ethnicity link - is there a photochemical link?

Edge, Ruth / Truscott, T George

Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology

2021 Volume 20, Issue 1, Page(s) 183–188

Abstract: A hypothesis is proposed to explain the increased detrimental effect of COVID-19 for Black, Asian and Minority Ethnic (BAME) men and women compared to Caucasian individuals. This is based on the differing photochemistry of phaeomelanin in fair skin and ... ...

Abstract	A hypothesis is proposed to explain the increased detrimental effect of COVID-19 for Black, Asian and Minority Ethnic (BAME) men and women compared to Caucasian individuals. This is based on the differing photochemistry of phaeomelanin in fair skin and eumelanin in dark/black skin. It is suggested that a range of reactive oxygen species, including, singlet oxygen and the superoxide radical anion, derived via direct photolysis of phaeomelanin, may escape the melanocyte and cause subsequent damage to the SARS-CoV-2 virus. It is further suggested that (large) carbon and sulphur peroxy radicals, from oxygen addition to radicals formed by carbon-sulphur bond cleavage, may assist via damage to the cell membranes. It is also speculated that light absorption by phaeomelanin and the subsequent C-S bond cleavage, leads to release of pre-absorbed reactive oxygen species, such as singlet oxygen and free radicals, which may also contribute to an enhanced protective effect for fair-skinned people.
MeSH term(s)	COVID-19/ethnology ; COVID-19/pathology ; COVID-19/virology ; Carbon/chemistry ; Ethnicity ; Female ; Free Radicals/chemistry ; Humans ; Light ; Male ; Melanins/chemistry ; Photochemical Processes ; Photolysis ; SARS-CoV-2/isolation & purification ; Singlet Oxygen/chemistry ; Singlet Oxygen/metabolism ; Skin/metabolism ; Sulfur/chemistry ; Superoxides/chemistry ; Superoxides/metabolism
Chemical Substances	Free Radicals ; Melanins ; Superoxides (11062-77-4) ; phaeomelanin (12627-61-1) ; eumelanin (12627-86-0) ; Singlet Oxygen (17778-80-2) ; Sulfur (70FD1KFU70) ; Carbon (7440-44-0)
Language	English
Publishing date	2021-01-08
Publishing country	England
Document type	Journal Article
ZDB-ID	2072584-X
ISSN	1474-9092 ; 1474-905X
ISSN (online)	1474-9092
ISSN	1474-905X
DOI	10.1007/s43630-020-00004-8
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Article ; Online: Photochemical and Photophysical Properties of Carotenoids and Reactive Oxygen Species

Fritz Boehm / Ruth Edge / T. George Truscott

Oxygen, Vol 3, Iss 21, Pp 322-

Contradictions Relating to Skin and Vision

2023 Volume 335

Abstract: Molecular mechanisms based on photo-physical processes involving dietary carotenoids, their radicals, and the role of oxygen are discussed and used to suggest explanations of the poorly understood and often contradictory results related to mainly skin ... ...

Abstract	Molecular mechanisms based on photo-physical processes involving dietary carotenoids, their radicals, and the role of oxygen are discussed and used to suggest explanations of the poorly understood and often contradictory results related to mainly skin and vision. Differing and conflicting efficiencies of singlet oxygen reactions with carotenoids of biological importance are discussed in environments from ‘simple’ organic solvents to single He La cells. A range of free radical reactions with carotenoids, and the corresponding radicals of the carotenoids themselves, are compared and used to explain the switch from beneficial to deleterious processes involving dietary carotenoids and to unravel their differing functions; of particular interest is a possible role for vitamin C.
Keywords	carotenoids ; β-carotene ; lycopene ; zeaxanthin ; lutein ; astaxanthin ; Analytical chemistry ; QD71-142 ; Inorganic chemistry ; QD146-197
Language	English
Publishing date	2023-08-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
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Article ; Online: Scavenging of Cation Radicals of the Visual Cycle Retinoids by Lutein, Zeaxanthin, Taurine, and Melanin.

Rozanowska, Malgorzata / Edge, Ruth / Land, Edward J / Navaratnam, Suppiah / Sarna, Tadeusz / Truscott, T George

International journal of molecular sciences

2023 Volume 25, Issue 1

Abstract: In the retina, retinoids involved in vision are under constant threat of oxidation, and their oxidation products exhibit deleterious properties. Using pulse radiolysis, this study determined that the bimolecular rate constants of scavenging cation ... ...

Abstract	In the retina, retinoids involved in vision are under constant threat of oxidation, and their oxidation products exhibit deleterious properties. Using pulse radiolysis, this study determined that the bimolecular rate constants of scavenging cation radicals of retinoids by taurine are smaller than 2 × 10
MeSH term(s)	Retinoids ; Vitamin A ; Melanins ; Retinaldehyde ; Lutein ; Zeaxanthins ; Taurine ; Cations
Chemical Substances	Retinoids ; Vitamin A (11103-57-4) ; Melanins ; Retinaldehyde (RR725D715M) ; Lutein (X72A60C9MT) ; Zeaxanthins ; Taurine (1EQV5MLY3D) ; Cations
Language	English
Publishing date	2023-12-29
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2019364-6
ISSN	1422-0067 ; 1422-0067 ; 1661-6596
ISSN (online)	1422-0067
ISSN	1422-0067 ; 1661-6596
DOI	10.3390/ijms25010506
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Article ; Online: Scavenging of Cation Radicals of the Visual Cycle Retinoids by Lutein, Zeaxanthin, Taurine, and Melanin

Malgorzata Rozanowska / Ruth Edge / Edward J. Land / Suppiah Navaratnam / Tadeusz Sarna / T. George Truscott

International Journal of Molecular Sciences, Vol 25, Iss 1, p

2023 Volume 506

Abstract	In the retina, retinoids involved in vision are under constant threat of oxidation, and their oxidation products exhibit deleterious properties. Using pulse radiolysis, this study determined that the bimolecular rate constants of scavenging cation radicals of retinoids by taurine are smaller than 2 × 10 7 M −1 s −1 whereas lutein scavenges cation radicals of all three retinoids with the bimolecular rate constants approach the diffusion-controlled limits, while zeaxanthin is only 1.4–1.6-fold less effective. Despite that lutein exhibits greater scavenging rate constants of retinoid cation radicals than other antioxidants, the greater concentrations of ascorbate in the retina suggest that ascorbate may be the main protectant of all visual cycle retinoids from oxidative degradation, while α-tocopherol may play a substantial role in the protection of retinaldehyde but is relatively inefficient in the protection of retinol or retinyl palmitate. While the protection of retinoids by lutein and zeaxanthin appears inefficient in the retinal periphery, it can be quite substantial in the macula. Although the determined rate constants of scavenging the cation radicals of retinol and retinaldehyde by dopa-melanin are relatively small, the high concentration of melanin in the RPE melanosomes suggests they can be scavenged if they are in proximity to melanin-containing pigment granules.
Keywords	retinal ; vitamin A ; free radicals ; xanthophylls ; carotenoids ; vitamin E ; Biology (General) ; QH301-705.5 ; Chemistry ; QD1-999
Subject code	333
Language	English
Publishing date	2023-12-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: Singlet Oxygen and Free Radical Reactions of Retinoids and Carotenoids-A Review.

Edge, Ruth / Truscott, T George

Antioxidants (Basel, Switzerland)

2018 Volume 7, Issue 1

Abstract: We report on studies of reactions of singlet oxygen with carotenoids and retinoids and a range of free radical studies on carotenoids and retinoids with emphasis on recent work, dietary carotenoids and the role of oxygen in biological processes. Many ... ...

Abstract	We report on studies of reactions of singlet oxygen with carotenoids and retinoids and a range of free radical studies on carotenoids and retinoids with emphasis on recent work, dietary carotenoids and the role of oxygen in biological processes. Many previous reviews are cited and updated together with new data not previously reviewed. The review does not deal with computational studies but the emphasis is on laboratory-based results. We contrast the ease of study of both singlet oxygen and polyene radical cations compared to neutral radicals. Of particular interest is the switch from anti- to pro-oxidant behavior of a carotenoid with change of oxygen concentration: results for lycopene in a cellular model system show total protection of the human cells studied at zero oxygen concentration, but zero protection at 100% oxygen concentration.
Language	English
Publishing date	2018-01-01
Publishing country	Switzerland
Document type	Journal Article ; Review
ZDB-ID	2704216-9
ISSN	2076-3921
ISSN	2076-3921
DOI	10.3390/antiox7010005
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Article ; Online: Anti- and pro-oxidative mechanisms comparing the macular carotenoids zeaxanthin and lutein with other dietary carotenoids - a singlet oxygen, free-radical in vitro and ex vivo study.

Boehm, Fritz / Edge, Ruth / Truscott, T George

Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology

2020 Volume 19, Issue 8, Page(s) 1001–1009

Abstract: The interactions of dietary carotenoids, and particularly the xanthophylls in the macula, with singlet oxygen and three different oxy-radicals, (hydroxyl radical, nitrogen dioxide and the superoxide radical anion) are compared using pulsed laser and γ- ... ...

Abstract	The interactions of dietary carotenoids, and particularly the xanthophylls in the macula, with singlet oxygen and three different oxy-radicals, (hydroxyl radical, nitrogen dioxide and the superoxide radical anion) are compared using pulsed laser and γ-techniques. The results give possible molecular mechanisms for the switch from anti-oxidant (protection) by carotenoids to pro-oxidant (damage) by carotenoids. The participation of oxygen in radical mechanisms in the presence of different carotenoids is compared for the different radicals. It is shown that the mechanistic role of oxygen differs very significantly for anti-/pro-oxidation by hydroxyl radicals when compared to nitrogen dioxide. Lutein was found to be an extremely good cell protector against hydroxyl radicals at all oxygen concentrations, including under physiological conditions.
MeSH term(s)	Antioxidants/chemistry ; Antioxidants/pharmacology ; Carotenoids/chemistry ; Carotenoids/pharmacology ; Free Radicals/chemistry ; Free Radicals/pharmacology ; Gamma Rays ; Lasers ; Lymphocytes/drug effects ; Oxidative Stress/drug effects ; Singlet Oxygen/chemistry ; Singlet Oxygen/pharmacology
Chemical Substances	Antioxidants ; Free Radicals ; Singlet Oxygen (17778-80-2) ; Carotenoids (36-88-4)
Language	English
Publishing date	2020-06-26
Publishing country	England
Document type	Comparative Study ; Journal Article
ZDB-ID	2072584-X
ISSN	1474-9092 ; 1474-905X
ISSN (online)	1474-9092
ISSN	1474-905X
DOI	10.1039/d0pp00120a
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Article: The Benefits and Risks of Certain Dietary Carotenoids that Exhibit both Anti- and Pro-Oxidative Mechanisms-A Comprehensive Review.

Black, Homer S / Boehm, Fritz / Edge, Ruth / Truscott, T George

Antioxidants (Basel, Switzerland)

2020 Volume 9, Issue 3

Abstract: Carotenoid pigments, particularly β-carotene and lycopene, are consumed in human foodstuffs and play a vital role in maintaining health. β-carotene is known to quench singlet oxygen and can have strong antioxidant activity. As such, it was proposed that ... ...

Abstract	Carotenoid pigments, particularly β-carotene and lycopene, are consumed in human foodstuffs and play a vital role in maintaining health. β-carotene is known to quench singlet oxygen and can have strong antioxidant activity. As such, it was proposed that β-carotene might reduce the risk of cancer. Epidemiological studies found inverse relationships between cancer risk and β-carotene intake or blood levels. However, clinical trials failed to support those findings and β-carotene supplementation actually increased lung cancer incidence in male smokers. Early experimental animal studies found dietary β-carotene inhibited UV-induced skin cancers. Later studies found that β-carotene supplementation exacerbated UV-carcinogenic expression. The discrepancies of these results were related to the type of diet the animals consumed. Lycopene has been associated with reduced risk of lethal stage prostate cancer. Other carotenoids, e.g., lutein and zeaxanthin, play a vital role in visual health. Numerous studies of molecular mechanisms to explain the carotenoids' mode of action have centered on singlet oxygen, as well as radical reactions. In cellular systems, singlet oxygen quenching by carotenoids has been reported but is more complex than in organic solvents. In dietary β-carotene supplement studies, damaging pro-oxidant reactivity can also arise. Reasons for this switch are likely due to the properties of the carotenoid radicals themselves. Understanding singlet oxygen reactions and the anti-/pro-oxidant roles of carotenoids are of importance to photosynthesis, vision and cancer.
Language	English
Publishing date	2020-03-23
Publishing country	Switzerland
Document type	Journal Article ; Review
ZDB-ID	2704216-9
ISSN	2076-3921
ISSN	2076-3921
DOI	10.3390/antiox9030264
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Article ; Online: A burst of genomic innovation at the origin of placental mammals mediated embryo implantation.

Taylor, Alysha S / Tinning, Haidee / Ovchinnikov, Vladimir / Edge, Jessica / Smith, William / Pullinger, Anna L / Sutton, Ruth A / Constantinides, Bede / Wang, Dapeng / Forbes, Karen / Forde, Niamh / O'Connell, Mary J

Communications biology

2023 Volume 6, Issue 1, Page(s) 459

Abstract: The origin of embryo implantation in mammals ~148 million years ago was a dramatic shift in reproductive strategy, yet the molecular changes that established mammal implantation are largely unknown. Although progesterone receptor signalling predates the ... ...

Abstract	The origin of embryo implantation in mammals ~148 million years ago was a dramatic shift in reproductive strategy, yet the molecular changes that established mammal implantation are largely unknown. Although progesterone receptor signalling predates the origin of mammals and is highly conserved in, and critical for, successful mammal pregnancy, it alone cannot explain the origin and subsequent diversity of implantation strategies throughout the placental mammal radiation. MiRNAs are known to be flexible and dynamic regulators with a well-established role in the pathophysiology of mammal placenta. We propose that a dynamic core microRNA (miRNA) network originated early in placental mammal evolution, responds to conserved mammal pregnancy cues (e.g. progesterone), and facilitates species-specific responses. Here we identify 13 miRNA gene families that arose at the origin of placental mammals and were subsequently retained in all descendent lineages. The expression of these miRNAs in response to early pregnancy molecules is regulated in a species-specific manner in endometrial epithelia of species with extreme implantation strategies (i.e. bovine and human). Furthermore, this set of miRNAs preferentially target proteins under positive selective pressure on the ancestral eutherian lineage. Discovery of this core embryo implantation toolkit and specifically adapted proteins helps explain the origin and evolution of implantation in mammals.
MeSH term(s)	Pregnancy ; Humans ; Cattle ; Animals ; Female ; Placenta/metabolism ; Eutheria/genetics ; Embryo Implantation/genetics ; Mammals/genetics ; MicroRNAs/genetics ; MicroRNAs/metabolism ; Genomics
Chemical Substances	MicroRNAs
Language	English
Publishing date	2023-04-26
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	2399-3642
ISSN (online)	2399-3642
DOI	10.1038/s42003-023-04809-y
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Article ; Online: Active Intermediates in Copper Nitrite Reductase Reactions Probed by a Cryotrapping-Electron Paramagnetic Resonance Approach.

Hedison, Tobias M / Shanmugam, Muralidharan / Heyes, Derren J / Edge, Ruth / Scrutton, Nigel S

Angewandte Chemie (International ed. in English)

2020 Volume 59, Issue 33, Page(s) 13936–13940

Abstract: Redox active metalloenzymes catalyse a range of biochemical processes essential for life. However, due to their complex reaction mechanisms, and often, their poor optical signals, detailed mechanistic understandings of them are limited. Here, we develop ... ...

Abstract	Redox active metalloenzymes catalyse a range of biochemical processes essential for life. However, due to their complex reaction mechanisms, and often, their poor optical signals, detailed mechanistic understandings of them are limited. Here, we develop a cryoreduction approach coupled to electron paramagnetic resonance measurements to study electron transfer between the copper centers in the copper nitrite reductase (CuNiR) family of enzymes. Unlike alternative methods used to study electron transfer reactions, the cryoreduction approach presented here allows observation of the redox state of both metal centers, a direct read-out of electron transfer, determines the presence of the substrate/product in the active site and shows the importance of protein motion in inter-copper electron transfer catalyzed by CuNiRs. Cryoreduction-EPR is broadly applicable for the study of electron transfer in other redox enzymes and paves the way to explore transient states in multiple redox-center containing proteins (homo and hetero metal ions).
MeSH term(s)	Catalytic Domain ; Crystallography, X-Ray ; Electron Spin Resonance Spectroscopy/methods ; Nitrite Reductases/metabolism ; Oxidation-Reduction ; Temperature
Chemical Substances	Nitrite Reductases (EC 1.7.-) ; nitrite reductase, copper-containing (EC 1.7.2.1)
Language	English
Publishing date	2020-06-04
Publishing country	Germany
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2011836-3
ISSN	1521-3773 ; 1433-7851
ISSN (online)	1521-3773
ISSN	1433-7851
DOI	10.1002/anie.202005052
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Article ; Online: Scavenging of Retinoid Cation Radicals by Urate, Trolox, and α-, β-, γ-, and δ-Tocopherols.

Rozanowska, Malgorzata / Edge, Ruth / Land, Edward J / Navaratnam, Suppiah / Sarna, Tadeusz / Truscott, T George

International journal of molecular sciences

2019 Volume 20, Issue 11

Abstract: Retinoids are present in human tissues exposed to light and under increased risk of oxidative stress, such as the retina and skin. Retinoid cation radicals can be formed as a result of the interaction between retinoids and other radicals or ... ...

Abstract	Retinoids are present in human tissues exposed to light and under increased risk of oxidative stress, such as the retina and skin. Retinoid cation radicals can be formed as a result of the interaction between retinoids and other radicals or photoexcitation with light. It has been shown that such semi-oxidized retinoids can oxidize certain amino acids and proteins, and that α-tocopherol can scavenge the cation radicals of retinol and retinoic acid. The aim of this study was to determine (i) whether β-, γ-, and δ-tocopherols can also scavenge these radicals, and (ii) whether tocopherols can scavenge the cation radicals of another form of vitamin A-retinal. The retinoid cation radicals were generated by the pulse radiolysis of benzene or aqueous solution in the presence of a selected retinoid under oxidizing conditions, and the kinetics of retinoid cation radical decays were measured in the absence and presence of different tocopherols, Trolox or urate. The bimolecular rate constants are the highest for the scavenging of cation radicals of retinal, (7 to 8) × 10
MeSH term(s)	Cations/chemistry ; Chromans/chemistry ; Free Radical Scavengers/chemistry ; Retinoids/chemistry ; Tocopherols/chemistry ; Uric Acid/chemistry
Chemical Substances	Cations ; Chromans ; Free Radical Scavengers ; Retinoids ; Uric Acid (268B43MJ25) ; Tocopherols (R0ZB2556P8) ; 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (S18UL9710X)
Language	English
Publishing date	2019-06-07
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2019364-6
ISSN	1422-0067 ; 1422-0067 ; 1661-6596
ISSN (online)	1422-0067
ISSN	1422-0067 ; 1661-6596
DOI	10.3390/ijms20112799
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