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Biochimica Et Biophysica Acta.... Apr 2022Under high light conditions, excess energy can damage the machinery of oxygenic photosynthesis. Plants have evolved a series of photoprotective processes, including... (Review)
Review
Under high light conditions, excess energy can damage the machinery of oxygenic photosynthesis. Plants have evolved a series of photoprotective processes, including conformational changes of the light-harvesting complexes that activate dissipation of energy as heat. In this mini-review, we will summarize our recent work developing and applying single-molecule methods to investigate the conformational states of the light-harvesting complexes. Through these measurements, we identified dissipative conformations and how they depend on conditions that mimic high light. Our studies revealed an equilibrium between the light-harvesting and dissipative conformations, and that the nature of the equilibrium varies with cellular environment, between proteins, and between species. Finally, we conclude with an outlook on open questions and implications for photosynthetic yields.
Topics: Light-Harvesting Protein Complexes; Photosynthesis; Protein Conformation; Tumor Necrosis Factor Ligand Superfamily Member 14
PubMed: 35202576
DOI: 10.1016/j.bbabio.2022.148543 -
Biochemical Society Transactions Apr 2018Photosynthesis uses sunlight to convert water and carbon dioxide into biomass and oxygen. When in excess, light can be dangerous for the photosynthetic apparatus because... (Review)
Review
Photosynthesis uses sunlight to convert water and carbon dioxide into biomass and oxygen. When in excess, light can be dangerous for the photosynthetic apparatus because it can cause photo-oxidative damage and decreases the efficiency of photosynthesis because of photoinhibition. Plants have evolved many photoprotective mechanisms in order to face reactive oxygen species production and thus avoid photoinhibition. These mechanisms include quenching of singlet and triplet excited states of chlorophyll, synthesis of antioxidant molecules and enzymes and repair processes for damaged photosystem II and photosystem I reaction centers. This review focuses on the mechanisms involved in photoprotection of chloroplasts through dissipation of energy absorbed in excess.
Topics: Antioxidants; Chlorophyll; Light; Photosynthesis; Photosystem I Protein Complex; Photosystem II Protein Complex; Plants; Radiation-Protective Agents
PubMed: 29666217
DOI: 10.1042/BST20170307 -
Frontiers in Medicine 2018Due to changes in human lifestyle (expanded sunbathing, the use of solaria, etc.) and, most importantly, increasing lifetime and thus higher cumulative exposure to solar... (Review)
Review
Due to changes in human lifestyle (expanded sunbathing, the use of solaria, etc.) and, most importantly, increasing lifetime and thus higher cumulative exposure to solar radiation, skin aging and skin cancer have become major health issues. As a consequence effective photoprotection is of outmost importance to humans. In this regard a lot has been learned in the past about the cellular and molecular basis underlying ultraviolet (UV) radiation-induced skin damage and, based on this knowledge, numerous skin protective approaches including organic and inorganic UV-filters, but also topically applicable antioxidants, DNA repair enzymes and compatible solutes as well as oral photoprotective strategies based on nutritional supplements have been developed. A new aspect is here that sun protection of human skin might even be possible after solar radiation-induced skin damage has occurred. A second, very important development was prompted by the discovery that also wavelengths beyond the UV spectrum can damage human skin. These include the blue light region of visible light (VIS) as well as the near infrared range (IRA) and corresponding sunprotection strategies have thus recently been or are still being developed. In this article we will provide a state of the art summary of these two novel developments and, at the end, we will also critically discuss strengths and weaknesses of the current attempts, which mainly focus on the prevention of skin damage by selected wavelengths but greatly ignore the possibility that wavelengths might interfere with each other. Such combined effects, however, need to be taken into account if photoprotection of human skin is intended to be global in nature.
PubMed: 29896475
DOI: 10.3389/fmed.2018.00162 -
Frontiers in Medicine 2018Electromagnetic radiation in the ultraviolet, visible, and infrared ranges produces biologic effects in humans. Where some of these effects are beneficial, others are... (Review)
Review
Electromagnetic radiation in the ultraviolet, visible, and infrared ranges produces biologic effects in humans. Where some of these effects are beneficial, others are harmful to the skin, particularly those stemming from ultraviolet radiation (UVR). Pharmacological photoprotection can be topical or systemic. Systemic photoprotection is often administered orally, complementing topical protection. New and classic oral agents (e.g., essential micronutrients as vitamins, minerals, polyphenols, carotenoids) are endowed with photoprotective and anti-photocarcinogenic properties. These substances bear the potential to increase systemic protection against the effects of electromagnetic radiation in the UV, visible, and infrared ranges. Protective mechanisms vary and include anti-oxidant, anti-inflammatory, and immunomodulatory effects. As such, they provide protection against UVR and prevent photo-induced carcinogenesis and aging. In this review, we present state of the art approaches regarding the photoprotective effects of vitamins and vitamin derivatives, dietary botanical, and non-botanical agents. A growing body of data supports the beneficial effects of oral photoprotection on the health of the skin. More studies will likely confirm and expand the positive impact of oral dietary botanicals as complementary measures for photoprotection.
PubMed: 29998107
DOI: 10.3389/fmed.2018.00188 -
The Plant Journal : For Cell and... May 2015Plants and algae require light for photosynthesis, but absorption of too much light can lead to photo-oxidative damage to the photosynthetic apparatus and sustained... (Review)
Review
Plants and algae require light for photosynthesis, but absorption of too much light can lead to photo-oxidative damage to the photosynthetic apparatus and sustained decreases in the efficiency and rate of photosynthesis (photoinhibition). Light stress can adversely affect growth and viability, necessitating that photosynthetic organisms acclimate to different environmental conditions in order to alleviate the detrimental effects of excess light. The model unicellular green alga, Chlamydomonas reinhardtii, employs diverse strategies of regulation and photoprotection to avoid, minimize, and repair photo-oxidative damage in stressful light conditions, allowing for acclimation to different and changing environments.
Topics: Antioxidants; Carotenoids; Chlamydomonas reinhardtii; Electron Transport; Gene Expression Regulation, Plant; Light; Mitochondria; Photosynthesis; Singlet Oxygen; Stress, Physiological; Tocopherols; Zeaxanthins
PubMed: 25758978
DOI: 10.1111/tpj.12825 -
Marine Drugs Sep 2015Photosynthetic pigments are bioactive compounds of great importance for the food, cosmetic, and pharmaceutical industries. They are not only responsible for capturing... (Review)
Review
Photosynthetic pigments are bioactive compounds of great importance for the food, cosmetic, and pharmaceutical industries. They are not only responsible for capturing solar energy to carry out photosynthesis, but also play a role in photoprotective processes and display antioxidant activity, all of which contribute to effective biomass and oxygen production. Diatoms are organisms of a distinct pigment composition, substantially different from that present in plants. Apart from light-harvesting pigments such as chlorophyll a, chlorophyll c, and fucoxanthin, there is a group of photoprotective carotenoids which includes β-carotene and the xanthophylls, diatoxanthin, diadinoxanthin, violaxanthin, antheraxanthin, and zeaxanthin, which are engaged in the xanthophyll cycle. Additionally, some intermediate products of biosynthetic pathways have been identified in diatoms as well as unusual pigments, e.g., marennine. Marine algae have become widely recognized as a source of unique bioactive compounds for potential industrial, pharmaceutical, and medical applications. In this review, we summarize current knowledge on diatom photosynthetic pigments complemented by some new insights regarding their physico-chemical properties, biological role, and biosynthetic pathways, as well as the regulation of pigment level in the cell, methods of purification, and significance in industries.
Topics: Diatoms; Molecular Structure; Photosynthesis; Pigments, Biological
PubMed: 26389924
DOI: 10.3390/md13095847 -
Marine Drugs Oct 2018Marine algae have received great attention as natural photoprotective agents due to their unique and exclusive bioactive substances which have been acquired as an... (Review)
Review
Marine algae have received great attention as natural photoprotective agents due to their unique and exclusive bioactive substances which have been acquired as an adaptation to the extreme marine environment combine with a range of physical parameters. These photoprotective substances include mycosporine-like amino acids (MAAs), sulfated polysaccharides, carotenoids, and polyphenols. Marine algal photoprotective substances exhibit a wide range of biological activities such as ultraviolet (UV) absorbing, antioxidant, matrix-metalloproteinase inhibitors, anti-aging, and immunomodulatory activities. Hence, such unique bioactive substances derived from marine algae have been regarded as having potential for use in skin care, cosmetics, and pharmaceutical products. In this context, this contribution aims at revealing bioactive substances found in marine algae, outlines their photoprotective potential, and provides an overview of developments of blue biotechnology to obtain photoprotective substances and their prospective applications.
Topics: Amino Acids; Animals; Aquatic Organisms; Biological Products; Carotenoids; Humans; Phaeophyceae; Polyphenols; Polysaccharides; Radiation-Protective Agents; Rhodophyta; Seaweed; Ultraviolet Rays
PubMed: 30360482
DOI: 10.3390/md16110399 -
Anais Brasileiros de Dermatologia 2014Brazil is a country of continental dimensions with a large heterogeneity of climates and massive mixing of the population. Almost the entire national territory is...
Brazil is a country of continental dimensions with a large heterogeneity of climates and massive mixing of the population. Almost the entire national territory is located between the Equator and the Tropic of Capricorn, and the Earth axial tilt to the south certainly makes Brazil one of the countries of the world with greater extent of land in proximity to the sun. The Brazilian coastline, where most of its population lives, is more than 8,500 km long. Due to geographic characteristics and cultural trends, Brazilians are among the peoples with the highest annual exposure to the sun. Epidemiological data show a continuing increase in the incidence of non-melanoma and melanoma skin cancers. Photoprotection can be understood as a set of measures aimed at reducing sun exposure and at preventing the development of acute and chronic actinic damage. Due to the peculiarities of Brazilian territory and culture, it would not be advisable to replicate the concepts of photoprotection from other developed countries, places with completely different climates and populations. Thus the Brazilian Society of Dermatology has developed the Brazilian Consensus on Photoprotection, the first official document on photoprotection developed in Brazil for Brazilians, with recommendations on matters involving photoprotection.
Topics: Brazil; Clothing; Electromagnetic Radiation; Environmental Exposure; Health Promotion; Humans; Meteorological Concepts; Radiation Protection; Skin Diseases; Skin Neoplasms; Solar Energy; Sunburn; Sunscreening Agents; Ultraviolet Rays; Vitamin D
PubMed: 25761256
DOI: 10.1590/abd1806-4841.20143971 -
International Journal of Molecular... May 2024Melatonin is ubiquitously present in all animals and plants, where it exerts a variety of physiological activities thanks to its antioxidant properties and its key role... (Review)
Review
Melatonin is ubiquitously present in all animals and plants, where it exerts a variety of physiological activities thanks to its antioxidant properties and its key role as the first messenger of extracellular signaling functions. Most of the clinical studies on melatonin refer to its widespread oral use as a dietary supplement to improve sleep. A far smaller number of articles describe the clinical applications of topical melatonin to treat or prevent skin disorders by exploiting its antioxidant and anti-inflammatory activities. This review focuses on the clinical studies in which melatonin was applied on the skin as a photoprotective, anti-aging, or hair growth-promoting agent. The methodologies and results of such studies are discussed to provide an overall picture of the state of the art in this intriguing field of research. The clinical studies in which melatonin was applied on the skin before exposure to radiation (UV, sunlight, and high-energy beams) were all characterized by an appropriate design (randomized, double-blind, and placebo-controlled) and strongly support its clinical efficacy in preventing or reducing skin damage such as dermatitis, erythema, and sunburn. Most of the studies examined in this review do not provide a clear demonstration of the efficacy of topical melatonin as a skin anti-aging or as a hair growth-promoting agent owing to limitations in their design and/or to the use of melatonin combined with extra active ingredients, except for one trial that suggests a possible beneficial role of melatonin in treating some forms of alopecia in women. Further research efforts are required to reach definitive conclusions concerning the actual benefits of topical melatonin to counteract skin aging and hair loss.
Topics: Melatonin; Humans; Administration, Topical; Antioxidants; Animals; Skin Aging; Clinical Studies as Topic; Skin; Skin Diseases
PubMed: 38791203
DOI: 10.3390/ijms25105167 -
Antioxidants (Basel, Switzerland) Jan 2023Ultraviolet (UV) radiation promotes the generation of reactive oxygen species (ROS) and nitrogen species (RNS), resulting in skin damage. Cosmetic industries have...
Ultraviolet (UV) radiation promotes the generation of reactive oxygen species (ROS) and nitrogen species (RNS), resulting in skin damage. Cosmetic industries have adopted a strategy to incorporate antioxidants in sunscreen formulations to prevent or minimize UV-induced oxidative damage, boost photoprotection effectiveness, and mitigate skin photoaging. Many antioxidants are naturally derived, mainly from terrestrial plants; however, marine organisms have been increasingly explored as a source of new potent antioxidant molecules. This work aims to characterize the frequency of the use of antioxidants in commercial sunscreens. Photoprotective formulations currently marketed in parapharmacies and pharmacies were analyzed with respect to the composition described on the label. As a result, pure compounds with antioxidant activity were found. The majority of sunscreen formulations contained antioxidants, with vitamin E and its derivatives the most frequent. A more thorough analysis of these antioxidants is also provided, unveiling the top antioxidant ingredients found in sunscreens. A critical appraisal of the scientific evidence regarding their effectiveness is also performed. In conclusion, this work provides an up-to-date overview of the use of antioxidants in commercial sunscreens for a better understanding of the advantages associated with their use in photoprotective formulations.
PubMed: 36670999
DOI: 10.3390/antiox12010138