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Communications Biology Feb 2022Light-harvesting complexes (LHCs) are pigment-protein complexes whose main function is to capture sunlight and transfer the energy to reaction centers of photosystems....
Light-harvesting complexes (LHCs) are pigment-protein complexes whose main function is to capture sunlight and transfer the energy to reaction centers of photosystems. In response to varying light conditions, LH complexes also play photoregulation and photoprotection roles. In algae and mosses, a sub-family of LHCs, light-harvesting complex stress-related (LHCSR), is responsible for photoprotective quenching. Despite their functional and evolutionary importance, no direct structural information on LHCSRs is available that can explain their unique properties. In this work, we propose a structural model of LHCSR1 from the moss P. patens, obtained through an integrated computational strategy that combines homology modeling, molecular dynamics, and multiscale quantum chemical calculations. The model is validated by reproducing the spectral properties of LHCSR1. Our model reveals the structural specificity of LHCSR1, as compared with the CP29 LH complex, and poses the basis for understanding photoprotective quenching in mosses.
Topics: Amino Acid Sequence; Bryopsida; Computer Simulation; Gene Expression Regulation, Plant; Light-Harvesting Protein Complexes; Pigments, Biological; Protein Conformation; Stress, Physiological
PubMed: 35177775
DOI: 10.1038/s42003-022-03083-8 -
Marine Drugs Dec 2023Marine macroalgae (seaweeds) are important primary global producers, with a wide distribution in oceans around the world from polar to tropical regions. Most of these... (Review)
Review
Marine macroalgae (seaweeds) are important primary global producers, with a wide distribution in oceans around the world from polar to tropical regions. Most of these species are exposed to variable environmental conditions, such as abiotic (e.g., light irradiance, temperature variations, nutrient availability, salinity levels) and biotic factors (e.g., grazing and pathogen exposure). As a result, macroalgae developed numerous important strategies to increase their adaptability, including synthesizing secondary metabolites, which have promising biotechnological applications, such as UV-absorbing Mycosporine-Like Amino Acid (MAAs). MAAs are small, water-soluble, UV-absorbing compounds that are commonly found in many marine organisms and are characterized by promising antioxidative, anti-inflammatory and photoprotective properties. However, the widespread use of MAAs by humans is often restricted by their limited bioavailability, limited success in heterologous expression systems, and low quantities recovered from the natural environment. In contrast, bloom-forming macroalgal species from all three major macroalgal clades (Chlorophyta, Phaeophyceae, and Rhodophyta) occasionally form algal blooms, resulting in a rapid increase in algal abundance and high biomass production. This review focuses on the bloom-forming species capable of producing pharmacologically important compounds, including MAAs, and the application of proteomics in facilitating macroalgal use in overcoming current environmental and biotechnological challenges.
Topics: Humans; Seaweed; Ultraviolet Rays; Seasons; Amino Acids; Rhodophyta
PubMed: 38132954
DOI: 10.3390/md21120633 -
Plants (Basel, Switzerland) Jan 2022Human skin works as a barrier against the adverse effects of environmental agents, including ultraviolet radiation (UVR). Exposure to UVR is associated with a variety of... (Review)
Review
Human skin works as a barrier against the adverse effects of environmental agents, including ultraviolet radiation (UVR). Exposure to UVR is associated with a variety of harmful effects on the skin, and it is one of the most common health concerns. Solar UVR constitutes the major etiological factor in the development of cutaneous malignancy. However, more than 90% of skin cancer cases could be avoided with appropriate preventive measures such as regular sunscreen use. Plants, constantly irradiated by sunlight, are able to synthesize specialized molecules to fight against UVR damage. Phenolic compounds, alkaloids and carotenoids constitute the major plant secondary metabolism compounds with relevant UVR protection activities. Hence, plants are an important source of molecules used to avoid UVR damage, reduce photoaging and prevent skin cancers and related illnesses. Due to its significance, we reviewed the main plant secondary metabolites related to UVR protection and its reported mechanisms. In addition, we summarized the research in Mexican plants related to UV protection. We presented the most studied Mexican plants and the photoprotective molecules found in them. Additionally, we analyzed the studies conducted to elucidate the mechanism of photoprotection of those molecules and their potential use as ingredients in sunscreen formulas.
PubMed: 35050108
DOI: 10.3390/plants11020220 -
Molecules (Basel, Switzerland) Mar 2023In this paper, the molecular and electronic structure of curcumin is studied. High-symmetric gas-phase tautomers and their deprotonated forms in various symmetry groups...
In this paper, the molecular and electronic structure of curcumin is studied. High-symmetric gas-phase tautomers and their deprotonated forms in various symmetry groups are identified. The stability of lower-symmetry structures was explained by using the Pseudo-Jahn-Teller (PJT) effect. This effect leads to stable structures of different symmetries for the neutral enol and keto forms. The presented analysis demonstrated the potential significance of the PJT effect, which may modulate the setting of electronic and vibrational (vibronic) energy levels upon photodynamic processes. The PJT effect may rationalize the photoprotection action and activity of naturally occurring symmetric dyes.
PubMed: 37049707
DOI: 10.3390/molecules28072946 -
The New Phytologist May 2023The Photochemical Reflectance Index (PRI) provides an optical indicator of photosynthetic light-use efficiency, photoprotection, and stress in plants. Although PRI can...
The Photochemical Reflectance Index (PRI) provides an optical indicator of photosynthetic light-use efficiency, photoprotection, and stress in plants. Although PRI can be applied in remote sensing, its interpretation depends on irradiance, which is hard to obtain from satellite or airborne imagery. To quantify forest photoprotective responses remotely, we developed a framework for modeling and interpreting PRI-light responses of individual trees and species using airborne imaging spectrometry coupled with georeferenced forest inventory data from a temperate broad-leaved forest. We derived an irradiance proxy, used hierarchical modeling to analyze PRI-light responses, and developed a framework of physiological interpretations of model parameters as facultative and constitutive components of photoprotection. Photochemical Reflectance Index declined with illumination, and PRI-light relationships varied with landscape position and among tree crowns and species. More sun-exposed foliage had lower intercepts and slopes of the relationship, indicating greater constitutive, but less facultative, photoprotection. We show that tree photoprotective strategies can be quantified at multiple scales using airborne hyperspectral data in structurally complex forests. Our findings and approach have important implications for the remote sensing of forest stress by offering a new way to assess functional diversity through dynamic differences in photoprotection and photosynthetic downregulation and providing previsual indicators of forest stress.
Topics: Trees; Photosynthesis; Forests; Plants; Spectrum Analysis; Plant Leaves
PubMed: 36658464
DOI: 10.1111/nph.18754 -
Science Advances Mar 2018Melanin is the primary photoprotecting pigment in humans as well as being implicated in the development of deadly melanoma. The material also conducts electricity and...
Melanin is the primary photoprotecting pigment in humans as well as being implicated in the development of deadly melanoma. The material also conducts electricity and has thus become a bioelectronic model for proton-to-electron transduction. Central to these phenomena are its spin properties-notably two linked species derived from carbon-centered and semiquinone radicals. Using a novel in situ photoinduced electron paramagnetic resonance technique with simultaneous electrical measurements, we have elucidated for the first time the distinct photoreactivity of the two different radical species. We find that the production of the semiquinone is light- and water-driven, explaining the electrical properties and revealing biologically relevant photoreactivity.
Topics: Electron Spin Resonance Spectroscopy; Free Radicals; Light; Melanins; Time Factors; Vacuum
PubMed: 29600273
DOI: 10.1126/sciadv.aaq1293 -
Preventive Medicine Reports Dec 2023Skin cancer incidence is increasing worldwide. Late adolescence and young adulthood are fundamental stages of life to acquire good sun exposure practices, regarding both...
Skin cancer incidence is increasing worldwide. Late adolescence and young adulthood are fundamental stages of life to acquire good sun exposure practices, regarding both personal involvement in skin cancer prevention and being a role model for others, especially in a health education environment. This descriptive cross-sectional study is based on the validated CHACES questionnaire to study sun exposure and photoprotection behavior among students and teachers at the School of Health Sciences in the National University of Chimborazo, Riobamba (Ecuador). University members (814 students (89.8 %) and 93 teachers (10.2 %)) were studied, with a predominance of females and light-skin phototypes in both groups. Similar results were obtained regarding sun exposure, with higher recreative exposure in the teachers' group and higher occupational exposure in students. However, students significantly showed lower avoiding midday sun (41.9 % vs 60.9 %), and lower use of sunglasses (10.1 % vs. 41.6 %). Attitudes towards the sun and photoprotection knowledge issues were also equivalent between students and teachers (6.1/10 vs 6.2/10). Students' sunburn rate last year reaches 88.4 % and 52.7 % in teachers (p < 0.001). Using a multivariable logistic regression model, we identified risk factors associated with a greater risk of sunburn in our population. This study highlights areas to be improved regarding knowledge, attitudes and, especially, practices of photoprotection, among students and teachers at the University of Chimborazo. These results point out that awareness-raising campaigns should be implemented to reduce sunburns, morbidity and mortality of skin cancer in this environment.
PubMed: 37886723
DOI: 10.1016/j.pmedr.2023.102458 -
Antioxidants (Basel, Switzerland) Nov 2021The aim of this study was to develop a new hybrid biomaterial that could photo-stabilize and improve the photoprotective capacity of a extract. Different combinations...
The aim of this study was to develop a new hybrid biomaterial that could photo-stabilize and improve the photoprotective capacity of a extract. Different combinations of lignin/gelatin/natural extract were applied to prepare hybrid biomaterial nanoparticles (NPs), which were then incorporated into an emulsion. The in vitro photoprotection and photostability were evaluated. The methanolic extract showed high phenolic content (646.4 ± 9.5 mg GAE/g dry extract) and a DPPH radical assay revealed that the antiradical capacity of the extract (0.13 to 0.05 g extract/mmol DPPH) was even better than that of BHT. The particle size of the hybrid biomaterial ranged from 100 to 255 nm; a polydispersity index (PdI) between 0.416 and 0.788 is suitable for topical use in dermocosmetic products. The loading capacity of the extract ranged from 27.0 to 44.5%, and the nanoparticles (NPs) showed electrostatic stability in accordance with the zeta potential value. We found that the formulation based on lignin: extract (1:1 ratio) and gelatin: lignin: extract (0.5:0.5:1 ratio) demonstrated photoprotection qualities with a sun protection factor (SPF) ranging from 9.4 to 22.6. In addition, all the hybrid NP-formulations were time-stable with %SPFeff and %UVAPFeff greater than 80% after exposure to 2 h of radiation. These results suggest that the hybrid biopolymer-natural extract improved the photoprotection and photostability properties, as well as the antiradical capacity, of the extract, and may be useful for trapping high polyphenol content from natural extracts, with potential application in cosmeceutical formulations.
PubMed: 34943007
DOI: 10.3390/antiox10121904 -
Plants (Basel, Switzerland) Feb 2023Overexposure to solar radiation has become an increasingly worrying problem due to the damage to the skin caused by ultraviolet radiation (UVR). In previous studies, the...
Overexposure to solar radiation has become an increasingly worrying problem due to the damage to the skin caused by ultraviolet radiation (UVR). In previous studies, the potential of an extract enriched with glycosylated flavonoids from the endemic Colombian high-mountain plant as a photoprotector and antioxidant was demonstrated. Therefore, in this work we sought to develop a dermocosmetic formulation with broad-spectrum photoprotection from the hydrolysates and purified polyphenols obtained from this species. Hence, the extraction of its polyphenols with different solvents was evaluated, followed by hydrolysis and purification, in addition to the characterization of its main compounds by HPLC-DAD and HPLC-MS, and evaluation of its photoprotective capacity through the measurement of the Sun Protection Factor (SPF), UVA Protection Factor (UVAPF), other Biological Effective Protection Factors (BEPFs), and its safety through the cytotoxicity. In the dry methanolic extract (DME) and purified methanolic extract (PME), flavonoids such as quercetin and kaempferol were found, which demonstrated antiradical capacity, as well as UVA-UVB photoprotection and prevention of harmful biological effects, such as elastosis, photoaging, immunosuppression, DNA damage, among others, which demonstrates the potential of the ingredients in this type of extract to be applied in photoprotection dermocosmetics.
PubMed: 36903840
DOI: 10.3390/plants12050979 -
Plant Physiology Jun 2022Fibrillins (FBNs) are the major structural proteins of plastoglobules (PGs) in chloroplasts. PGs are associated with defense against abiotic and biotic stresses, as well...
Fibrillins (FBNs) are the major structural proteins of plastoglobules (PGs) in chloroplasts. PGs are associated with defense against abiotic and biotic stresses, as well as lipid storage. Although FBN2 is abundant in PGs, its independent function under abiotic stress has not yet been identified. In this study, the targeting of FBN2 to PGs was clearly demonstrated using an FBN2-YFP fusion protein. FBN2 showed higher expression in green photosynthetic tissues and was upregulated at the transcriptional level under high-light stress. The photosynthetic capacity of fbn2 knockout mutants generated using CRISPR/Cas9 technology decreased rapidly compared with that of wild-type (WT) plants under high-light stress. In addition to the photoprotective function of FBN2, fbn2 mutants had lower levels of plastoquinone-9 and plastochromanol-8. The fbn2 mutants were highly sensitive to methyl jasmonate (MeJA) and exhibited root growth inhibition and a pale-green phenotype due to reduced chlorophyll content. Consistently, upon MeJA treatment, the fbn2 mutants showed faster leaf senescence and more rapid chlorophyll degradation with decreased photosynthetic ability compared with the WT plants. The results of this study suggest that FBN2 is involved in protection against high-light stress and acts as an inhibitor of jasmonate-induced senescence in Arabidopsis (Arabidopsis thaliana).
Topics: Arabidopsis; Arabidopsis Proteins; Chlorophyll; Chloroplasts; Cyclopentanes; Fibrillin-2; Gene Expression Regulation, Plant; Oxylipins; Plant Leaves; Plant Physiological Phenomena
PubMed: 35404409
DOI: 10.1093/plphys/kiac166