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Cyanobacteria uniquely contain a primitive water-soluble carotenoprotein, the orange carotenoid protein (OCP). Nearly all extant cyanobacterial genomes contain genes for the OCP or its homologs, implying an evolutionary constraint for cyanobacteria to conserve its function. Genes encoding the OCP and its two constituent structural domains, the N-terminal domain, helical carotenoid proteins (HCPs), and its C-terminal domain, are found in the most basal lineages of extant cyanobacteria. These three carotenoproteins exemplify the importance of the protein for carotenoid properties, including protein dynamics, in response to environmental changes in facilitating a photoresponse and energy quenching. Here, we review new structural insights for these carotenoproteins and situate the role of the protein in what is currently understood about their functions.

Photosynthesis has been using energy from sunlight to assimilate atmospheric CO2 for at least 3.5 billion years. Through evolution and natural selection, photosynthetic organisms have flourished in almost all aquatic and terrestrial environments. This is partly due to the diversity of light-harvesting complex (LHC) proteins, which facilitate photosystem assembly, efficient excitation energy transfer, and photoprotection. Structural advances have provided angstrom-level structures of many of these proteins and have expanded our understanding of the pigments, lipids, and residues that drive LHC function. In this review, we compare and contrast recently observed cryo-electron microscopy structures across photosynthetic eukaryotes to identify structural motifs that underlie various light-harvesting strategies. We discuss subtle monomer changes that result in macroscale reorganization of LHC oligomers. Additionally, we find recurring patterns across diverse LHCs that may serve as evolutionary stepping stones for functional diversification. Advancing our understanding of LHC protein-environment interactions will improve our capacity to engineer more productive crops.

Melanin, particularly eumelanin, is commonly viewed as an efficient antioxidant and photoprotective pigment. Nonetheless, the ability of melanin to photogenerate reactive oxygen species and sensitize the formation of cyclobutane pyrimidine dimers may contribute to melanin‐dependent phototoxicity. The phototoxic potential of melanin depends on a variety of factors, including molecular composition, redox state, and degree of aggregation. Using complementary spectroscopic and analytical methods we analyzed the physicochemical properties of Dopa‐melanin, a synthetic model of eumelanin, subjected to oxidative degradation induced by aerobic photolysis or exposure to 0.1 M hydrogen peroxide. Both modes of oxidative degradation were accompanied by dose‐dependent bleaching of melanin and irreversible modifications of its paramagnetic, ion‐ and electron‐exchange and antioxidant properties. Bleached melanin exhibited enhanced efficiency to photogenerate singlet oxygen in both UVA and short‐wavelength visible light. Although chemical changes of melanin subunits, including a relative increase of DHICA content and disruption of melanin polymer induced by oxidative degradation were considered, these two mechanisms may not be sufficient for a satisfactory explanation of the elevated photosensitizing ability of the bleached eumelanin. This study points out possible adverse changes in the photoprotective and antioxidant properties of eumelanin that could occur in pigmented tissues after exposure to high doses of intense solar radiation. [ABSTRACT FROM AUTHOR]

The acclimation of the green algae Chlamydomoas reinhardtii to high light (HL) has been studied predominantly under continuous illumination of the cells. Here, we investigated the impact of fluctuating HL in alternation with either low light (LL) or darkness on photosynthetic performance and on photoprotective responses. Compared to intervening LL phases, dark phases led to (1) more pronounced reduction of the photosystem II quantum efficiency, (2) reduced degradation of the PsbS protein, (3) lower energy dissipation capacity and (4) an increased pool size of the xanthophyll cycle pigments. These characteristics indicate increased photo‐oxidative stress when HL periods are interrupted by dark phases instead of LL phases. This overall trend was similar when comparing long (8 h) and short (30 min) HL phases being interrupted by long (16 h) and short (60 min) phases of dark or low light, respectively. Only the degradation of PsbS was clearly more efficient during long (16 h) LL phases when compared to short (60 min) LL phases. Summary Statement: The performance of the unicellular green alga Chlamydomonas reinhardtii has been studied so far, mostly under continuous illumination conditions. We investigated the impact of fluctuating high light (HL) on the photosynthetic performance and the photoprotective response in C. reinhardtii. Our data indicate that intervening dark phases negatively affect cell growth and lead to a delay of HL acclimation processes, including the activation of energy dissipation. [ABSTRACT FROM AUTHOR]

UV-A radiation contributes to photoaging/photocarcinogenesis by generating inflammation and oxidative damage. Current photoprotective strategies are limited by the availability/utilization of UV-A filters, highlighting an unmet need. Cannabidiol (CBD), having anti-inflammatory/antioxidant properties via regulation of nuclear erythroid 2–related factor, heme oxygenase 1, and peroxisome proliferator-activated receptor gamma, could potentially mitigate damage from UV-A exposure. This is a prospective, single-center, pilot clinical trial (NCT05279495). Nineteen participants applied nano-CBD (nCBD) or vehicle (VC) cream to randomized, blinded buttock sites twice daily for 14 days; then, the treated sites were irradiated with ≤3× UV-A minimal erythema dose. After 24 hours, punch biopsies were obtained for histology, immunohistochemistry, and real-time polymerase chain reaction. At 24 hours, 21% of participants had less observed erythema on CBD-treated skin than on VC skin. Histologically, nCBD-treated skin had reduced UV-A–induced epidermal hyperplasia than VC (P =.01). Immunohistochemistry detected reduced cytoplasmic/nuclear 8-oxoguanine glycosylase 1 staining in nCBD-treated skin compared with VC (P <.01). Quantitative mtDNA polymerase chain reaction demonstrated that UV-A–induced deletion of ND4 (proxy:4977 bp deletion; P =.003) and ND1 (proxy:3895 bp deletion; P =.002) was significantly reduced by in vivo nCBD treatment compared with VC. Small sample size is this study's limitation. Topically applied nCBD cream reduced UV-A–induced formation of a frequent mutagenic nuclear DNA base lesion and protected against mtDNA mutations associated with UV-A–induced skin aging. To our knowledge, this trial is the first to identify UV-protective capacity of CBD-containing topicals in humans. [ABSTRACT FROM AUTHOR]

Sunscreen products can protect the skin against the harmful effects of UV radiation, including reddening, aging, and cancer. The aim of this research was to evaluate the photoprotective effects of yeast pulcherrimin, an iron-chelating dipeptide. We first investigated the cytotoxicity of pulcherrimin produced by Metschnikowia pulcherrima yeast on the human keratinocyte HaCaT cell line, using the PrestoBlue assay. We assessed the ability of pulcherrimin to induce DNA repair after the exposure of HaCaT cells to oxidative stress. We also evaluated its protective activity against UVC radiation. The sun protective factor (SPF) was calculated using the Mansur equation. The UVA/UVB ratio values for pure pulcherrimin were evaluated using the Boots Star Rating system. The critical wavelength was determined by calculating the integrated optical density curve area. Based on the results, pulcherrimin shows strong cytoprotective effects through antioxidant and photoprotective activities on the HaCaT cell line. The calculated SPFs were 20 and 15 at pH = 7 and pH = 10, respectively. The critical wavelength above 370 nm and the UVA/UVB ratio R > 1 suggest that yeast pulcherrimin—a cyclic dipeptide containing iron—may be considered a promising photoprotective agent. [ABSTRACT FROM AUTHOR]

The influence of UV radiation on skin discoloration, skin aging and the development of skin cancer is widely known. As a part of this study, the effect of extracts from three varieties of Cornus mas L. (C. mas L.) on skin cells exposed to UVA radiation was assessed. The analyses were performed on both normal and cancer skin cells. For this purpose, the potential photoprotective effects of the obtained extracts (aqueous and ethanolic) was assessed by performing two cytotoxicity tests (Alamar blue and Neutral red). Additionally, the antioxidant capacity was compared using three different assays. The 2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA) probe was used to evaluate the intracellular level of free radicals in cells exposed to the simultaneous action of UVA radiation and dogwood extracts. Additionally, the ability to inhibit excessive pigmentation was determined by assessing the inhibition of melanin formation and tyrosinase activity. The obtained results confirmed the strong antioxidant properties of dogwood extracts and their photoprotective effect on normal skin cells. The ability to inhibit the viability of melanoma cells was also observed. Additionally, a reduction in oxidative stress in skin cells exposed to UVA radiation and a strong inhibition of melanin formation and tyrosinase activity have been demonstrated. This study shows that dogwood extract could be a valuable cosmetic raw material that can play both a photoprotective and antihyperpigmentation role in cosmetic preparations. [ABSTRACT FROM AUTHOR]

This study focuses on the synthesis and characterization of 2D polygonic ZnO microplatelets for application as UV filters in sunscreens. ZnO microplatelets are obtained via a simple method involving chemical precipitation, aging, and calcination. XRD, SEM, and TEM analyses confirm the successful formation of ZnO microplatelets. DRUV‐Vis studies indicate that the ZnO microplatelets have a band gap energy value of 3.2 eV and exhibit good UV radiation absorption, similar to a commercial ZnO reference sample. Furthermore, in methylene blue photodegradation studies, the ZnO microplatelets show significantly lower photocatalytic activity than the ZnO reference sample. Under UV irradiation of 254 nm and 365 nm wavelengths, the dye in contact with ZnO microplatelets is photodegraded by only 38 % and 69 % after 5 h, compared to the reference sample, which photodegraded the dye by 87 % and 97 %, respectively. The performance of a sunscreen formulation containing the ZnO microplatelets (at 10 wt %), in terms of the photoprotection factors and photostability, is on par with that of a formulation containing the ZnO reference sample. Due to their microplatelet structure, good UVR absorption capacity, and relatively lower photocatalytic activity, the ZnO microplatelets show potential for application as UV filters in sunscreen products. [ABSTRACT FROM AUTHOR]

Arthospira platensis and Spirulina platensis microalgae are a rich source of pro-health metabolites (% d.m.): proteins (50.0–71.3/46.0–63.0), carbohydrates (16.0–20.0/12.0–17.0), fats (0.9–14.2/6.4–14.3), polyphenolic compounds and phenols (7.3–33.2/7.8–44.5 and 4.2/0.3 mg GAE/g), and flavonoids (1.9/0.2 QUE/g) used in pharmaceutical and cosmetic formulations. This review summarises the research on the chemical profile, therapeutic effects in dermatological problems, application of Arthrospira and Spirulina microalgae, and contraindications to their use. The pro-health properties of these microalgae were analysed based on the relevant literature from 2019 to 2024. The antiviral mechanism of microalgal activity involves the inhibition of viral replication and enhancement of immunity. The anti-acne activity is attributed to alkaloids, alkanes, phenols, alkenes, phycocyanins, phthalates, tannins, carboxylic and phthalic acids, saponins, and steroids. The antibacterial activity generally depends on the components and structure of the bacterial cell wall. Their healing effect results from the inhibition of inflammatory and apoptotic processes, reduction of pro-inflammatory cytokines, stimulation of angiogenesis, and proliferation of fibroblasts and keratinocytes. The photoprotective action is regulated by amino acids, phlorotannins, carotenoids, mycosporins, and polyphenols inhibiting the production of tyrosinase, pro-inflammatory cytokines, and free oxygen radicals in fibroblasts and the stimulation of collagen production. Microalgae are promising molecular ingredients in innovative formulations of parapharmaceuticals and cosmetics used in the prophylaxis and therapy of dermatological problems. This review shows the application of spirulina-based commercial skin-care products as well as the safety and contraindications of spirulina use. Furthermore, the main directions for future studies of the pro-health suitability of microalgae exerting multidirectional effects on human skin are presented. [ABSTRACT FROM AUTHOR]

Xero-halophytes are the salt-tolerant plants of dry habitats that adapt efficient strategies to endure extreme salt and water fluctuations. This study elucidated the adaptations related to PSII photochemistry, photoprotection, and photoinhibition in six C4 xero-halophytes (Atriplex stocksii , Haloxylon stocksii , Salsola imbricata, Suaeda fruticosa, Desmostachya bipinnata , and Saccharum griffithii) grown in their native habitats. Chlorophyll a fluorescence quenching measurements suggested that S. imbricata and H. stocksii maintained efficient PSII photochemistry by downregulating heat dissipation and keeping a high fraction of open PSII centres that indicates plastoquinone (PQ) pool oxidation. Fluorescence induction kinetics revealed that S. imbricata demonstrated the highest performance index of PSII excitation to the reduction of end electron acceptors. S. fruticosa sustained photochemical efficiency through enhanced dissipation of excess energy and a low fraction of open PSII centres, indicating PQ reduced state. The large light-harvesting antenna size, deduced from the chlorophyll a / b ratio in S. fruticosa apparently led to the superior performance index of PSII excitation to the reduction of intersystem electron carriers. A. stocksii retained more open PSII centres with responsive non-photochemical quenching to safely dissipate excess energy. Despite maintaining the highest pigment contents and stoichiometry, A. stocksii remained lowest in both performance indices. The grass species D. bipinnata and S. griffithii kept fewer PSII centres open during photoinhibition, as evidenced by downregulation of PSII operating efficiency. The results provide insights into the differential modulation of PSII photochemical efficiency through dynamic control of photoprotective energy dissipation, PQ pool redox states, and photoinhibitory shutdown in these xero-halophytes. Photochemical adaptations of six C4 xero-halophytes reveal diverse strategies to endure salt and water fluctuations in native habitats. Variations in photochemistry, photoprotection, and photoinhibition indicate modulation of PSII photochemical efficiency. Different xero-halophytes exhibit distinct mechanisms for maintaining photochemical efficiency through dynamic control of plastoquinone pool redox states, excess energy dissipation, and shutdown mechanisms in response to environmental challenges. [ABSTRACT FROM AUTHOR]

Two recent studies reinvestigated the phenomenon of photorespiration as a photoprotective mechanism. Smith et al. suggest alleviated negative feedback regulation of chloroplast ATP synthase as an alternative hypothesis. Von Bismarck et al. discuss how photorespiration-impaired mutants cope somewhat better with fluctuating light (FL) environments because of downregulated photosynthesis and complex metabolic re-routing. [ABSTRACT FROM AUTHOR]

Blue light accelerates retinal aging. Previous studies have indicated that wavelengths between 400 and 455 nm are most harmful to aging retinal pigment epithelia (RPE). This study explored whether filtering these wavelengths can protect cells exposed to broad sunlight. Primary porcine RPE cells loaded with 20 µM A2E were exposed to emulated sunlight filtered through eye media at 1.8 mW/cm2 for 18 h. Filters selectively filtering out light over 400–455 nm and a dark-yellow filter were interposed. Cell damage was measured by apoptosis, hydrogen peroxide (H2O2) production, and mitochondrial membrane potential (MMP). Sunlight exposure increased apoptosis by 2.7-fold and H2O2 by 4.8-fold, and halved MMP compared to darkness. Eye Protect SystemTM (EPS) technology, filtering out 25% of wavelengths over 400–455 nm, reduced apoptosis by 44% and H2O2 by 29%. The Multilayer Optical Film (MOF), at 80% of light filtered, reduced apoptosis by 91% and H2O2 by 69%, and increased MMP by 73%, overpassing the dark-yellow filter. Photoprotection increased almost linearly with blue-violet light filtering (400–455 nm) but not with total blue filtering (400–500 nm). Selective filters filtering out 25% (EPS) to 80% (MOF) of blue-violet light offer substantial protection without affecting perception or non-visual functions, making them promising for preventing light-induced retinal damage with aesthetic acceptance for permanent wear. [ABSTRACT FROM AUTHOR]

UV radiation causes long- and short-term skin damage, such as erythema and skin cancer. Therefore, the use of sunscreens is extremely important. However, concerns about UV filter safety have prompted exploration into alternative solutions, with nanotechnology emerging as a promising avenue. This systematic review identified 23 experimental studies utilizing nanocarriers to encapsulate sunscreens with the aim of enhancing their efficacy and safety. Polymeric and lipid nanoparticles are frequently employed to encapsulate both organic and inorganic UV filters along with natural antioxidants. Nanocarriers have demonstrated benefits including reduced active ingredient usage, increased sun protection factor, and mitigated photoinstability. Notably, they also decreased the skin absorption of UV filters. In summary, nanocarriers represent a viable strategy for improving sunscreen formulations, offering enhanced physicochemical properties and bolstered photoprotective effects, thereby addressing concerns regarding UV filter safety and efficacy in cosmetic applications. [ABSTRACT FROM AUTHOR]

The rice, like other plants, undergoes photoprotection mode by increasing nonphotochemical quenching (NPQ) in high light intensity (> 1200 µmol m− 2s− 1 PPFD), which attenuates photosystem II yield (φPSII) drastically. The plant remains in photoprotection mode even after light intensity becomes not stressful for an extended period. While there are significant differences in the time it takes for photoprotection to recover among different genotypes, its use is limited in plant breeding because measuring the chlorophyll fluorescence parameters in progressive actinic light after dark adaptation takes more than forty-five minutes per genotype. The study finds that instantly measured A400/A1800 ratio by five minutes in flag leaves of 25 diverse genotypes strongly associated with the φPSII400 differences between theoretical and actual, qPd400 and NPQ400 with R2 values 0.74, 0.65 and 0.60, respectively. In two consecutive years, GWAS of A400/A1800 ratio identified the regions with genes reported earlier for plant photoprotection recovery. Additionally, QTL analysis in a RIL population also identified the regions carrying known genes related to photoprotection. Thus, the A400/A1800 ratio can quickly phenotype many plants for easier introgression of the traits in popular cultivars. The identified genotypes, genes, and QTLs can be used to improve yield potential and allele mining. [ABSTRACT FROM AUTHOR]

The physiological role of α‐melanocyte stimulating hormone in regulating integumental pigmentation of many vertebrate species has been recognized since the 1960's. However, its physiological significance for human pigmentation remained enigmatic until the 1990's. α‐Melanocyte stimulating hormone and related melanocortins are synthesized locally in the skin, primarily by keratinocytes, in addition to the pituitary gland, and therefore act as paracrine factors for melanocytes. Human melanocytes express the melanocortin 1 receptor, which recognizes α‐melanocyte stimulating hormone and the related adrenocorticotropic hormone as agonists. This review summarizes the current knowledge of the pleotropic effects of the activated melanocortin 1 receptor that maintain human melanocyte homeostasis by regulating melanogenesis and the response to environmental stressors, mainly solar radiation. Certain allelic variants of the melanocortin 1 receptor gene are associated with specific pigmentary phenotypes in various human populations. Variants associated with red hair phenotype compromise the function of the encoded receptor. Activation of the human melanocortin 1 receptor regulates eumelanin synthesis and enhances DNA damage response of melanocytes to solar radiation and oxidative stressors. We describe how synthetic selective melanocortin 1 receptor agonists can be efficacious as sunless tanning agents, for treatment of vitiligo and photosensitivity disorders, and for prevention of skin cancer, including melanoma. [ABSTRACT FROM AUTHOR]

Plants have evolved various photosynthetic adaptations and photoprotective mechanisms to survive in fluctuating and extreme light environments. Many light-activated photosynthetic proteins and enzymes adjust to plant leaf anatomy and leaf pigments to facilitate these processes. Under excessive amounts of light, plants use non-photochemical quenching (NPQ) mechanisms to dissipate excess absorbed light energy as heat to prevent photoinhibition and, therefore, mitigate damage to the plant's photosystems. In this study, we examined photosynthetic adaptations to the light environment in common beans using representative genotypes of the Andean (Calima) and the Mesoamerican (Jamapa) gene pools. We estimated their leaf chlorophyll fluorescence characteristics using dark- and light-adapted mature leaves from three-week-old plants. Our results indicated a higher chlorophyll fluorescence of the light-adapted leaves in the Mesoamerican genotype. NPQ induction was early and extended in the Andean genotype. A similar response in the Mesoamerican counterpart required high light intensity (≥1500 PAR). The NPQ relaxation was rapid in the Mesoamerican genotype (t1/2: 6.76 min) but sluggish in the Andean genotype (t1/2: 9.17 min). These results indicated variable adaptation to light environments between the two common bean genotypes and suggested different strategies for surviving fluctuating light environments that can be exploited for developing plants with environmentally efficient photosynthesis under light limitations. [ABSTRACT FROM AUTHOR]

Background: Dark‐skinned individuals (DSI) present high rates of melasma and post‐inflammatory hyperpigmentation. The use of sunscreens with mineral filters is essential for prevention and treatment. Our objective was to determine the preferences of dermatologists and dermatology residents in the prescription of sunscreens for DSI. Methods: An anonymous survey of attendees at an online photoprotection event held on March 31, 2022, in Spain. Results: The survey was answered by 66.6% (221/332) of the attendees: 159 dermatologists (71.9%) and 62 dermatology residents (28.1%). Respondents reported recommending the use of sunscreen to a median of 80% of DSI [interquartile range (IQR), 50–90]. Physicians reported prescribing tinted sunscreens to a median percentage of 60% (IQR, 25–90) of DSI with acne; and to a median percentage of 90% (IQR, 58–99) of DSI with melasma. The most prescribed photoprotectors to DSI with melasma were organic broad‐spectrum sunscreens with antioxidants: 102/220 (46.4%) and mineral broad‐spectrum sunscreens (with iron oxides): 45/220 (20.4%). In DSI with melasma or other pigmentary disorders, the most preferred features of sunscreens were as follows: sun protection factor ≥ 30: 217/221 (98.2%), UVA protection: 214/221 (96.8%), color for camouflage: 150/220 (68.2%) and mineral filters such as titanium dioxide and zinc oxide: 151/220 (68.6%) or iron oxides: 131/220 (59.5%). Limitations: Online survey, potential inclusion bias. Conclusions: Respondents reported to prescribe sunscreens to the majority of DSI, and tinted sunscreens for the majority of DSI with pigmentary disorders. However, the most frequently recommended sunscreens for DSI were organic broad‐spectrum sunscreens with antioxidants. [ABSTRACT FROM AUTHOR]

The field of sun protection is quickly changing and the research article by Douki et al., published in the current issue of Photochemistry and Photobiology, reported key experimental data that will certainly help the development of better sun care products. Mutagenic photoproducts (CPDs, cyclobutane pyrimidine dimers and 6‐4PPs, pyrimidine‐6‐4‐pyrimidone photoproducts) were formed in the reconstructed human epidermis (RHE) by UVB (312 nm) irradiation, and their concentrations were detected by HPLC‐MS/MS as a function of time after the UVB treatment. RHE had been previously exposed or not (control) to blue light (427 nm). Both CPDs and 6‐4PPs were shown to last longer in blue‐light irradiated RHE, proving the inhibition of the DNA repair by blue light exposure. This is a highly relevant information because sunscreens allow people to enjoy longer periods under the sun and consequently, to endure very high doses of blue light. The work also reported results obtained with RHEs previously treated with a sunscreen formulation containing a broadband filter that offers blue‐light protection. Interestingly, authors observed that the DNA repair was not significantly inhibited in RHE previously treated with the sunscreen offering broadband protection. Readers will find a scientifically sound proof of the importance of blue‐light protection in sun care products. [ABSTRACT FROM AUTHOR]

In recent years, interest is growing in the biological cutaneous effects of high‐energy visible light (400–450 nm). In the present study, we explored the impact of blue light (BL) on the repair of pyrimidine dimers, the major class of premutagenic DNA damage induced by exposure to sunlight. We unambiguously demonstrate that the exposure of in vitro reconstructed human epidermis to environmentally relevant doses of BL strongly decreases the rate of repair of cyclobutane pyrimidine dimers and pyrimidine (6‐4) pyrimidone photoproducts induced by a subsequent UVB irradiation. Using the highly sensitive and specific liquid chromatography‐tandem mass spectrometry assay, we did not observe induction of pyrimidine dimers by BL alone. Finally, we showed that application, during the BL exposure step, of a formula containing a new filter, named TriAsorB and affording BL photoprotection, prevented the decrease in DNA repair efficiency. These results emphasize the potential deleterious effects of BL on DNA repair and the interest in providing adequate skin protection against this wavelength range of sunlight. [ABSTRACT FROM AUTHOR]

Exposure of parenteral nutrition (PN) to light induces hydroperoxide (HPO) formation whose toxicity, especially in pediatrics, is documented. In this context, we evaluated the efficacy of photoprotection medical devices used in our institution to protect PN from degradation after two different exposures to light. A mixed oil lipid emulsion (Smoflipid®) in standard or opaque syringes and a ternary PN mixture bags (Numetah®) with or without opaque overwrap were exposed for at least 420 min to a xenon lamp. Samples of Smoflipid® in standard or opaque syringes were also exposed for 24 h to conditions reproducing those of a neonatal intensive care unit. The use of opaque syringes for Smoflipid® administration or opaque overwraps for Numetah® administration reduced HPO formation by an average of 14% and 40%, respectively, compared to standard conditions after at least 420 min to a xenon lamp. When Smoflipid® samples were administered with standard or opaque syringes and exposed to a phototherapy lamp, the fold‐change in the HPO concentration increased, respectively, by 6.3 or 5.4 at 24 h compared with syringes unexposed to phototherapy lamp. Although the observed differences were non‐significant, it nonetheless appears prudent to use photoprotection of PN during administration, particularly in patients with immature or compromised antioxidant capacity. [ABSTRACT FROM AUTHOR]

Excessive ultraviolet (UV) radiation causes a series of adverse effects on human skin, such as erythema and tanning due to the produce of endogenous melanin of human skin. Inspired by the self‐defense mechanism of human skin to prevent UV radiation damage, we construct a natural and biocompatible Carb@PDA−L sunscreen hydrogel by doping melanin‐like L‐lysine doped polydopamine (PDA−L) to biocompatible poly‐γ‐glutamic acid based hydrogel matrix Carb, which displays good biosafety, efficient UV shielding performance and excellent antioxidative and anti‐inflammatory performance in the application of the skin protection of sun and repair after sunburn. The melanin‐like PDA−L can be synthesized by the oxidative polymerization of dopamine triggered by L‐lysine under alkali‐free condition, which exhibits increase absorption intensity in the UV region and better reactive oxygen species removal performance compared with undoped polydopamine in the perspective of a UV absorber. Meanwhile, PDA−L, as the synthetic analogue of natural melanin, has good biosafety, which can avoid the skin oxidative damage and penetrative toxicity of the conventional sunscreen. [ABSTRACT FROM AUTHOR]

Leilei Zhao,1 Xinmeng Fu,2 Hongbin Cheng3 1School of Clinical Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, People’s Republic of China; 2Traditional Chinese Medicine Department, Boao Yiling Life Care Center, Qionghai, Hainan Province, People’s Republic of China; 3Department of Dermatology, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan Province, People’s Republic of ChinaCorrespondence: Hongbin Cheng, Email chenghongbin@cdutcm.edu.cnAbstract: Melasma is a benign but emotionally distressing skin condition that reduces patients’ quality of life, with prevalence rates during pregnancy ranging from 36.4% to 75%. Troublingly, up to 30% of cases are reported to persist after delivery, even ten years later. And recurrence and aggravation are common in subsequent pregnancies. This review examines the risk factors and mechanisms associated with melasma during pregnancy and summarized corresponding preventive strategies. We emphasize the critical role of photoprotection, including the use of sunscreens from the first trimester, in reducing the incidence of melasma.Keywords: melasma, pregnancy, risk factors, prevention, photoprotection

Abstract The rice, like other plants, undergoes photoprotection mode by increasing nonphotochemical quenching (NPQ) in high light intensity (> 1200 µmol m− 2s− 1 PPFD), which attenuates photosystem II yield (φPSII) drastically. The plant remains in photoprotection mode even after light intensity becomes not stressful for an extended period. While there are significant differences in the time it takes for photoprotection to recover among different genotypes, its use is limited in plant breeding because measuring the chlorophyll fluorescence parameters in progressive actinic light after dark adaptation takes more than forty-five minutes per genotype. The study finds that instantly measured A400/A1800 ratio by five minutes in flag leaves of 25 diverse genotypes strongly associated with the φPSII400 differences between theoretical and actual, qPd400 and NPQ400 with R2 values 0.74, 0.65 and 0.60, respectively. In two consecutive years, GWAS of A400/A1800 ratio identified the regions with genes reported earlier for plant photoprotection recovery. Additionally, QTL analysis in a RIL population also identified the regions carrying known genes related to photoprotection. Thus, the A400/A1800 ratio can quickly phenotype many plants for easier introgression of the traits in popular cultivars. The identified genotypes, genes, and QTLs can be used to improve yield potential and allele mining.

Abstract Background Skin cancer is the most common form of cancer in Ireland with over 13,000 new cases diagnosed annually. People with inflammatory bowel disease are at higher risk of developing skin cancer. Objectives The aim of this study is to assess inflammatory bowel disease (IBD) patients' awareness around skin cancer risk and photoprotection practices and to identify gaps in patient education regarding skin cancer prevention in IBD patients. Methods IBD patients >18 years old were invited to fill out a questionnaire while waiting for their outpatient appointment. Results A total of 87 patients (52% women) with IBD (Crohn's disease 62.8%, UC 35%,) were included. A total of 38 patients were diagnosed before age 25 (44%). Most patients were on active treatment for their IBD (96.5%, n = 85). Four patients had a personal history, and seven patients had a family history of skin cancer. Nearly half of participants (47.6%) were unaware or unsure of an increased risk of skin cancer associated with IBD and 42.5% were unaware or unsure of an increased risk with some IBD treatments. Behaviours around sun‐cream were generally good, however, other sun protective methods were suboptimal. Conclusions Only half (52.4%) of IBD patients surveyed were aware of a link between skin cancer and IBD. Skin cancer knowledge was generally good, however, photoprotection practices were suboptimal. This underscores the role of healthcare professionals in re‐enforcing sun safety information and skin cancer education in the IBD population.

Climate change is globally affecting rainfall patterns, necessitating the improvement of drought tolerance in crops. Sorghum bicolor is a relatively drought-tolerant cereal. Functional stay-green sorghum genotypes can maintain green leaf area and efficient grain filling during terminal post-flowering water deprivation, a period of ~10 weeks. To obtain molecular insights into these characteristics, two drought-tolerant genotypes, BTx642 and RTx430, were grown in replicated control and terminal post-flowering drought field plots in Californias Central Valley. Photosynthetic, photoprotective, and water dynamics traits were quantified and correlated with metabolomic data collected from leaves, stems, and roots at multiple timepoints during control and drought conditions. Physiological and metabolomic data were then compared to longitudinal RNA sequencing data collected from these two genotypes. The unique metabolic and transcriptomic response to post-flowering drought in sorghum supports a role for the metabolite galactinol in controlling photosynthetic activity through regulating stomatal closure in post-flowering drought. Additionally, in the functional stay-green genotype BTx642, photoprotective responses were specifically induced in post-flowering drought, supporting a role for photoprotection in the molecular response associated with the functional stay-green trait. From these insights, new pathways are identified that can be targeted to maximize yields under growth conditions with limited water.

Bentonites and montmorillonites, natural clay minerals originating from volcanic ash, possess unique properties that have traditionally been utilized in industrial applications. Recently, their potential biomedical applications, particularly in dermatology, have garnered significant interest. This review explores the cutaneous benefits of bentonites and montmorillonites, highlighting their anti-inflammatory, wound-healing, oil-absorbing, drug delivery, photoprotective, and anti-aging effects. Evidence from in vitro experiments, animal studies, and preliminary clinical trials demonstrate that these clays can significantly reduce inflammation, accelerate wound healing, absorb excess oil, enhance drug delivery, protect against ultraviolet radiation, and improve skin hydration and elasticity. Larger scale randomized clinical trials (RCTs) are needed to further establish the safety and efficacy of bentonites and montmorillonites. Given the increasing consumer demand for natural ingredients in skincare, bentonites and montmorillonites present a promising area for further research and development in dermatologic applications. [ABSTRACT FROM AUTHOR]

It has long been hypothesized that benthic motile pennate diatoms use phototaxis to optimize photosynthesis and minimize photoinhibitory damage by adjusting their position within vertical light gradients in coastal benthic sediments. However, experimental evidence to test this hypothesis remains inconclusive, mainly due to methodological difficulties in studying cell behavior and photosynthesis over realistic spatial microscale gradients of irradiance and cell position. In this study, a novel experimental approach was developed and used to test the hypothesis of photosynthesis optimization through motility, based on the combination of single-cell in vivo chlorophyll fluorometry and microfluidic chips. The approach allows the concurrent study of behavior and photosynthetic activity of individual cells of the epipelic diatom species Craspedostauros britannicus exposed to a light microgradient of realistic dimensions, simulating the irradiance and distance scales of light microgradients in benthic sediments. Following exposure to light, (i) cells explored their light environment before initiating light-directed motility; (ii) cells used motility to lower their light dose, when exposed to the highest light intensities; and (iii) motility was combined with reversible non-photochemical quenching, to allow cells to avoid photoinhibition. The results of this proof-of-concept study not only strongly support the photoprotective nature of photobehavior in the studied species but also revealed considerable variability in how individual cells reacted to a light microgradient. The experimental setup can be readily applied to study motility and photosynthetic light responses of other diatom species or natural assemblages, as well as other photoautotrophic motile microorganisms, broadening the toolset for experimental microbial ecology research. [ABSTRACT FROM AUTHOR]

Abstract Background Strict photoprotection is crucial for persons living with albinism (PWAs), especially in Nigeria where the level of solar ultraviolet radiation is particularly high, which further increases the susceptibility of this population to develop photodermatoses and, ultimately, skin cancer. Objectives This study aimed to assess the knowledge and attitude towards photoprotection among PWAs in Uyo, Akwa Ibom, Nigeria. Methods A descriptive cross‐sectional study involving consenting 50 participants with oculocutaneous albinism was recruited through interviewer‐administered questionnaires. Data analysis utilised SPSS 26. Results The use of sun‐protective clothing was the predominant photoprotective measure (62%) with an overall low sun‐protection strategy usage of 5% and 10% knowledge rate, despite 80% acknowledging the daily use of various forms of photoprotection. Cost was cited as the commonest deterrent to poor use of sunscreen (47.8%). Conclusions Poor awareness and photoprotection usage amongst persons with albinism in Uyo are discouragingly below standard increasing their risk of developing photodermatoses which adversely affects their quality of life. Therefore, dermatologists should improve collaborative efforts at addressing barriers such as cost and enhancing knowledge about effective photoprotection strategies.

Plectranthus scutellaroides is a plant with attractive colored leaves. It contains secondary metabolite compounds such as flavonoids and phenolics, which provide skin protection against ultraviolet rays from the sun. The research aims to investigate the activity of P. scutellarioides leaf extract from various variants and different solvents on sunscreen, skin lightening, and anti aging activities. The best extract is formulated in gel dosage form. Each P. scutellaroides leaf was extracted using ethanol, ethyl acetate, and hexane as solvents. The obtained extract was assessed for Sun Protecting Factor (SPF), UVA Protection grade (PA), antioxidant activity, and inhibition of tyrosinase, collagenase, elastase, and hyaluronidase. Determination was conducted in vitro using spectrophotometric methods. The highest sunscreen activity was observed in the ethanol extract Va (Va-ET), which exhibited SPF and PA values of 25.618±0.265, and 0.681±0.007 (star 3), respectively at a concentration of 100 ug/mL. The most significant skin-lightening activity was observed in the ethanol extract Vc (Vc-ET), with an IC50 value inhibiting tyrosinase of 39.059 ug/mL. Regarding the anti-aging activity of the extracts, as determined by their antioxidant activity and inhibition of collagenase, elastase, and hyaluronidase, the most promising extracts were obtained from ethanol extract Va (Va-ET) and ethyl acetate extract Va (Va-EA), with IC50 values of 79.734, 76.838, 143.384, and 122.467 ug/ mL, respectively. The Va-ET was formulated into a gel dosage form, and there was a significant effect of the gelling agent on the SPF value of the extract after formulation (p < 0.05). All extracts exhibit activity as sunscreen, skin lightening, and anti-aging, with the Va-ET showing the highest efficacy. Gelling agents significantly influence the SPF value of extracts after formulation into the gel dosage form. Among them, F3, formulated from the Va-ET of P. scutellaroides using Carbopol-940 as a gelling agent, exhibits the highest efficacy.

Abstract Background The purpose of this study was to investigate the photoprotection effect of peroxiredoxin 1 (PRDX1) protein in ultraviolet B (UVB) irradiation-induced damage of retinal pigment epithelium (RPE) and its possible molecular mechanism. Methods ARPE-19 cell viability and apoptosis were assessed by MTT assay and flow cytometry, respectively. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect the PRDX1 expression. The corresponding kits were employed to measure the levels or activities of lactate dehydrogenase (LDH), 8-hydroxy-2-deoxyguanosine (8-OHdG), reactive oxygen species (ROS), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD). Western blotting was applied to examine PRDX1 expression and mitogen-activated protein kinase (MAPK) signaling pathway-related proteins. Results After exposure to 20 mJ/cm2 intensity of UVB irradiation for 24 h, ARPE-19 cells viability was decreased, the leakage degree of LDH and 8-OHdG were increased, and cell apoptosis was elevated. The expression of PRDX1 was significantly down-regulated in UVB-induced ARPE-19 cells. The low expression of PRDX1 was involved in high irradiation intensity. Overexpression of PRDX1 increased cell activity, decreased cell apoptosis, and LDH as well as 8-OHdG leakage in UVB-induced ARPE-19 cells. In addition to alleviating UVB-induced cell damage, PRDX1 overexpression also inhibited UVB-induced oxidative stress (down-regulation of ROS and MDA levels, up-regulation of GSH-Px and SOD activities) and the activation of MAPK signaling pathway in ARPE-19 cells. Conclusion PRDX1 exerts a photoprotection effect on RPE by attenuating UVB-induced cell damage and inhibiting oxidative stress, which can be attributed to the inhibition of MAPK signaling pathway activation.

Abstract Background Despite extensive research on sun protection, there remains a gap in certain populations like Lebanon. It is essential to assess how Lebanese adults handle sun exposure and its risks. Objectives To examine the knowledge and habits of sun protection use among adults in Lebanon and explore the possible association between a history of skin cancer or photo‐related disorder and sun protection behaviours. Methods We conducted a single‐centre cross‐sectional study on 1001 patients presenting to the American University of Beirut Medical Center dermatology clinics from August 2020 till April 2023. Participants were between 18 and 80 years of age and recruited by convenience sampling. Those younger than 18 years old or not proficient in English or Arabic were excluded. Results Among 1001 adults (mean age, 36.06 years [SD, 14.72]; 708 [71.08%] female), 512 (52.78%) use sunscreen, 449 (46.29%) do not and 9 (0.93%) do not know. Respondents with a history of a photo‐related condition (melasma, lentigos/freckles and rosacea) were significantly more likely to be sunscreen users (p

The productivity of microalgal cultures and their resilience to unfavorable conditions is largely determined by the availability of mineral nutrients, particularly nitrogen. Nitrogen starvation is a strong stressor that induces a broad range of responses in microalgae at the cell and cell population (culture) levels. These responses such as lipogenesis and secondary carotenogenesis are widely used in biotechnology to obtain valuable secondary metabolites of microalgae. It was believed that microalgal cells lack specific structures that function as long-term nitrogen depot, but recent studies assigned this role to microcrystalline inclusions constituted by nitrogenous bases (most often guanine). It is also known that purine microcrystals are biophotonic structures widespread in nature. These structures modify the intensity and spectral composition of radiation in illuminated cells and tissues of living organisms. In this regard, we studied (i) the dynamics of the formation of guanine crystals in the cells of green carotenogenic microalgae from the genus Coelastrella (C. thermophila NAMSU CM1/23 and C. rubescens IPPAS C-2066) depending on the availability of nitrogen in the medium and (ii) the effect of the presence of these crystals on cell resilience to high light intensity. Nitrogen-rich crystal inclusions were accumulated in cells when the cultures reached the stationary growth phase in a medium with ample nitrate nitrogen. During rapid growth, these inclusions were hardly detectable in the cells and disappeared during cultivation in the absence of nitrogen. Optical polarization microscopy and Raman microspectroscopy demonstrated that these nitrogen-rich inclusions are birefringent microcrystals composed of guanine. C. thermophila cells harboring abundant guanine crystals showed resistance to short-term (10–15 min) exposure to high-intensity light (600 µmol PAR quanta/m2/s). The results obtained are discussed in the context of the multifaceted role of guanine crystals in the stress tolerance of microalgae. [ABSTRACT FROM AUTHOR]

Neoporphyra haitanensis, a red alga harvested for food, thrives in the intertidal zone amid dynamic and harsh environments. High irradiance represents a major stressor in this habitat, posing a threat to the alga's photosynthetic apparatus. Interestingly, N. haitanensis has adapted to excessive light despite the absence of a crucial xanthophyll cycle‐dependent photoprotection pathway. Thus, it is valuable to investigate the mechanisms by which N. haitanensis copes with excessive light and to understand the photoprotective roles of carotenoids. Under high light intensities and prolonged irradiation time, N. haitanensis displayed reduction in photosynthetic efficiency and phycobiliproteins levels, as well as different responses in carotenoids. The decreased carotene contents suggested their involvement in the synthesis of xanthophylls, as evidenced by the up‐regulation of lycopene‐β‐cyclase (lcyb) and zeaxanthin epoxidase (zep) genes. Downstream xanthophylls such as lutein, zeaxanthin, and antheraxanthin increased proportionally to light stress, potentially participating in scavenging reactive oxygen species (ROS). When accompanied by the enhanced activity of ascorbate peroxidase (APX), these factors resulted in a reduction in ROS production. The responses of intermediates α‐cryptoxanthin and β‐cryptoxanthin were felt somewhere between carotenes and zeaxanthin/lutein. Furthermore, these changes were ameliorated when the organism was placed in darkness. In summary, down‐regulation of the organism's photosynthetic capacity, coupled with heightened xanthophylls and APX activity, activates photoinhibition quenching (qI) and antioxidant activity, helping N. haitanensis to protect the organism from the damaging effects of excessive light exposure. These findings provide insights into how red algae adapt to intertidal lifestyles. [ABSTRACT FROM AUTHOR]

Photosynthesis is the foundation of life on Earth. However, if not well regulated, it can also generate excessive reactive oxygen species (ROS), which can cause photodamage. Regulation of photosynthesis is highly dynamic, responding to both environmental and metabolic cues, and occurs at many levels, from light capture to energy storage and metabolic processes. One general mechanism of regulation involves the reversible oxidation and reduction of protein thiol groups, which can affect the activity of enzymes and the stability of proteins. Such redox regulation has been well studied in stromal enzymes, but more recently, evidence has emerged of redox control of thylakoid lumenal enzymes. This review/hypothesis paper summarizes the latest research and discusses several open questions and challenges to achieving effective redox control in the lumen, focusing on the distinct environments and regulatory components of the thylakoid lumen, including the need to transport electrons across the thylakoid membrane, the effects of pH changes by the proton motive force (pmf) in the stromal and lumenal compartments, and the observed differences in redox states. These constraints suggest that activated oxygen species are likely to be major regulatory contributors to lumenal thiol redox regulation, with key components and processes yet to be discovered. [ABSTRACT FROM AUTHOR]

Objective The objective of this study was to assess the prevalence and characteristics of, and knowledge about, photosensitivity and the use of photoprotective measures in an international cohort of cutaneous lupus erythematosus and SLE patients. Methods We conducted an international, cross-sectional study based on a 46-question web-based survey, including patients with medically confirmed lupus erythematosus, conducted between November 2021 and April 2022. Results A total of 600 patients with lupus erythematosus [94% female, median age: 41 years, interquartile range (IQR): 33–51] from 50 countries were included. A history of photosensitivity was reported by 389/600 (64.8%) patients. Photosensitivity was associated with the presence of other cutaneous involvement [odds ratio (OR) = 3.8; 95% CI 2.5–5.7; P  < 0.001] and differed according to the area of residence and level of education (P  < 0.001, for all). Photosensitivity was characterized by a wide range of clinical manifestations (both cutaneous and systemic symptoms in 56.1% and systemic symptoms only in 29.8% of patients). Fatigue was the most frequently reported systemic manifestation (82.3%). Overall, 559/600 (93%) patients were aware of the detrimental role of ultraviolet radiation exposure in lupus erythematosus, but 160/480 (33.3%) were unaware of the importance of photoprotective measures, including 90/310 (29%) among those with photosensitivity. Conclusion A high rate of self-reported photosensitivity characterizes lupus erythematosus patients. Photosensitivity frequently includes subjective features, which makes it difficult to evaluate in clinical practice. As fatigue is frequent in lupus erythematosus, further study is needed to clarify the causal link with ultraviolet radiation exposure. About one-third of lupus erythematosus patients are unaware of the importance of photoprotective measures. This should be improved through more frequent and targeted awareness interventions. [ABSTRACT FROM AUTHOR]

Dyschromia is a top diagnosis among African Americans (AA). Sunscreen is an essential part of its management, but AA have low sunscreen use. We sought to examine the perception of sunscreen utility in dyschromia and photoaging among patients who identify as AA or Black. This cross-sectional study recruited participants from the Case Western Reserve University Academic Dental Clinic. Participants completed an electronic survey that contained questions related to sunscreen use, knowledge of the sun’s role in hyperpigmentation and photoaging, and whether sunscreen could be used for hyperpigmentation and photoaging. Of the 151 participants recruited, 63.6% (n = 96) were women and 36.4% (n = 57) were men. Consistent with previous reports, participants had lower sunscreen use (20.5%) than whites (43.5%). The majority of participants (80.1% and 58.3%, respectively) didn’t attribute the sun to hyperpigmentation or photoaging. Participants with dark/brown spots were significantly more likely to not attribute the sun to hyperpigmentation than those without spots. (p = 0.003) Limitations for this study include its small sample size, recall and reporter bias, question misinterpretation, and lack of question neutrality. This study highlights the knowledge gap of a major contributing factor to dyschromia which in turn could be leading to their view of the decreased utility of sunscreen. [ABSTRACT FROM AUTHOR]

SUMMARY: Enhancing the efficiency of photosynthesis represents a promising strategy to improve crop yields, with keeping the steady state of PSII being key to determining the photosynthetic performance. However, the mechanisms whereby the stability of PSII is maintained in oxygenic organisms remain to be explored. Here, we report that the Psb28 protein functions in regulating the homeostasis of PSII under different light conditions in Arabidopsis thaliana. The psb28 mutant is much smaller than the wild‐type plants under normal growth light, which is due to its significantly reduced PSII activity. Similar defects were seen under low light and became more pronounced under photoinhibitory light. Notably, the amounts of PSII core complexes and core subunits are specifically decreased in psb28, whereas the abundance of other representative components of photosynthetic complexes remains largely unaltered. Although the PSII activity of psb28 was severely reduced when subjected to high light, its recovery from photoinactivation was not affected. By contrast, the degradation of PSII core protein subunits is dramatically accelerated in the presence of lincomycin. These results indicate that psb28 is defective in the photoprotection of PSII, which is consistent with the observation that the overall NPQ is much lower in psb28 compared to the wild type. Moreover, the Psb28 protein is associated with PSII core complexes and interacts mainly with the CP47 subunit of PSII core. Taken together, these findings reveal an important role for Psb28 in the protection and stabilization of PSII core in response to changes in light environments. Significance Statement: The small protein Psb28 plays a crucial role in the protection and stabilization of PSII reaction center via direct interaction with the CP47 subunit of PSII core complexes in the model plant Arabidopsis thaliana, providing novel insights into the maintenance of PSII function for boosting photosynthetic capacity in response to changing light environments. [ABSTRACT FROM AUTHOR]

Context: Although quantum mechanical calculations have proven effective in accurately predicting UV absorption and assessing the antioxidant potential of compounds, the utilization of computer-aided drug design (CADD) to support sustainable synthesis research of new sunscreen active ingredients remains an area with limited exploration. Furthermore, there are ongoing concerns about the safety and effectiveness of existing sunscreens. Therefore, it remains crucial to investigate photoprotection mechanisms and develop enhanced strategies for mitigating the harmful effects of UVR exposure, improving both the safety and efficacy of sunscreen products. A previous study conducted synthesis research on eight novel hybrid compounds (I–VIII) for use in sunscreen products by molecular hybridization of trans-resveratrol (RESV), avobenzone (AVO), and octinoxate (OMC). Herein, time-dependent density functional theory (TD-DFT) calculations performed in the gas phase on the isolated hybrid compounds (I–VIII) proved to reproduce the experimental UV absorption. Resveratrol-avobenzone structure-based hybrids (I–IV) present absorption maxima in the UVB range with slight differences between them, while resveratrol-OMC structure-based hybrids (V–VIII) showed main absorption in the UVA range. Among RESV-OMC hybrids, compounds V and VI exhibited higher UV absorption intensity, and compound VIII stood out for its broad-spectrum coverage in our simulations. Furthermore, both in silico and in vitro analyses revealed that compounds VII and VIII exhibited the highest antioxidant activity, with compound I emerging as the most reactive antioxidant within RESV-AVO hybrids. The study suggests a preference for the hydrogen atom transfer (HAT) mechanism over single-electron transfer followed by proton transfer (SET-PT) in the gas phase. With a strong focus on sustainability, this approach reduces costs and minimizes effluent production in synthesis research, promoting the eco-friendly development of new sunscreen active ingredients. Methods: The SPARTAN'20 program was utilized for the geometry optimization and energy calculations of all compounds. Conformer distribution analysis was performed using the Merck molecular force field 94 (MMFF94), and geometry optimization was carried out using the parametric method 6 (PM6) followed by density functional theory (DFT/B3LYP/6-31G(d)). The antioxidant behavior of the hybrid compounds (I–VIII) was determined using the highest occupied molecular orbital (εHOMO) and the lowest unoccupied molecular orbital (εLUMO) energies, as well as the bond dissociation enthalpy (BDE), ionization potential (IP), and proton dissociation enthalpy (PDE) values, all calculated at the same level of structural optimization. TD-DFT study is carried out to calculate the excitation energy using the B3LYP functional with the 6-31G(d) basis set. The calculated transitions were convoluted with a Gaussian profile using the Gabedit program. [ABSTRACT FROM AUTHOR]

Ocular health has emerged as one of the major issues of global health concern with a decline in quality of life in an aging population, in particular and rise in the number of associated morbidities and mortalities. One of the chief reasons for vision impairment is oxidative damage inflicted to photoreceptors in rods and cone cells by blue light as well as UV radiation. The scenario has been aggravated by unprecedented rise in screen-time during the COVID and post-COVID era. Lutein and Zeaxanthin are oxygenated carotenoids with proven roles in augmentation of ocular health largely by virtue of their antioxidant properties and protective effects against photobleaching of retinal pigments, age-linked macular degeneration, cataract, and retinitis pigmentosa. These molecules are characterized by their characteristic yellow-orange colored pigmentation and are found in significant amounts in vegetables such as corn, spinach, broccoli, carrots as well as fish and eggs. Unique structural signatures including tetraterpenoid skeleton with extensive conjugation and the presence of hydroxyl groups at the end rings have made these molecules evolutionarily adapted to localize in the membrane of the photoreceptor cells and prevent their free radical induced peroxidation. Apart from the benefits imparted to ocular health, lutein and zeaxanthin are also known to improve cognitive function, cardiovascular physiology, and arrest the development of malignancy. Although abundant in many natural sources, bioavailability of these compounds is low owing to their long aliphatic backbones. Under the circumstances, there has been a concerted effort to develop vegetable oil-based carriers such as lipid nano-emulsions for therapeutic administration of carotenoids. This review presents a comprehensive update of the therapeutic potential of the carotenoids along with the challenges in achieving an optimized delivery tool for maximizing their effectiveness inside the body. Lutein and zeaxanthin are the two most abundant natural xanthophylls (oxygenated carotenoids) with a linear C40 tetraterpene/isoprenoid lycopene-based backbone. Presence of extensive conjugation (more than 10 double bonds) enable these molecules to act as accessory light harvesting pigments apart from chlorophyll. More importantly, the xanthophylls prevent photobleaching of the pigments and proteins in the Light Harvesting Complex (LHC) by sequestering the excess unutilized blue light and preventing triplet chlorophyll associated formation of Reactive Oxygen Species. In human eye, lutein, zeaxanthin along with mesozeaxanthin constitute the three macular pigments forming the so called "yellow spot" of the macula and are implicated in maintaining the redox balance, homeostasis and normal physiology of the eyes. However, unlike plants, xanthophylls must be acquired from dietary sources such as colored leafy vegetables and egg yolk. Increase in the number of eye diseases in the aging population coupled with insufficient bioavailability of xanthophylls has mandated the industrial production of supplements enriched in xanthophylls. The bioavailability and delivery of xanthophylls can be significantly enhanced by suspension in a blend of extra-virgin olive oil and other vegetable oils. [ABSTRACT FROM AUTHOR]

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This work demonstrates the potentials of a commercially available few-layer graphene (FLG) in enhancing the electro-dissipative properties, mechanical strength, and UV protection of polyolefin blend composites; interesting features of electronic packaging materials. Polyethylene (PE)/ polypropylene (PP)/ FLG blend composites were prepared following two steps. Firstly, different concentrations of FLG were mixed with either the PE or PP phases. Subsequently, in the second step, this pre-mixture was melt-blended with the other phase of the blend. FLG-filled composites were characterized in terms of electrical conductivity, morphological evolution upon shear-induced deformation, mechanical properties, and UV stability of polyolefin blend composites. Premixing of FLG with the PP phase has been observed to be a better mixing strategy to attain higher electrical conductivity in PE/PP/FLG blend composite. This observation is attributed to the influential effect of FLG migration from a thermodynamically less favourable PP phase to a favourable PE phase via the PE/PP interface. Interestingly, the addition of 4 wt.% (~2 vol.%) and 5 wt.% (~2.5 vol.%) of FLG increased an electrical conductivity of ~10 orders of magnitude in PE/PP—60/40 (1.87 × 10−5 S/cm) and PE/PP—20/80 (1.25 × 10−5 S/cm) blends, respectively. Furthermore, shear-induced deformation did not alter the electrical conductivity of the FLG-filled composite, indicating that the conductive FLG network within the composite is resilient to such deformation. In addition, 1 wt.% FLG was observed to be sufficient to retain the original mechanical properties in UV-exposed polyolefin composites. FLG exhibited pronounced UV stabilizing effects, particularly in PE-rich blends, mitigating surface cracking and preserving ductility. [ABSTRACT FROM AUTHOR]

AbstractAcute sun exposure could lead to erythema and inflammation. This Investigation aims to determine the efficacy of the complexation of peppermint oil (PO) with cyclodextrin in enhancing its physicochemical properties. Nano-organogels were prepared by direct hot melting method. Cyclodextrin (CD) PO was prepared by co-lyophilized method and included in F6. The particle size values were all below 150 nm. F6 polymeric showed high antioxidant activity, in vitro SPF, and stability. CD nano-organogel showed the least release and the highest skin deposition values. This high skin deposition is assured by confocal microscopy. Histology revealed its anti-inflammatory effect against acute UV irradiation. PO CD nano-organogel demonstrates a promising modality for anti-inflammatory therapy against UV irradiation. [ABSTRACT FROM AUTHOR]

High solar radiation, combined with high temperature, causes losses in plant production. The application of foliar protector in plants is associated with improvements in photosynthesis, reduction in leaf temperature and, consequently, improved productivity. Two experiments were conducted. The first aimed to assess the efficacy of foliar protector versus artificial shading in mitigating the negative impacts of excessive radiation and temperature on the physiology, growth, and yield of common bean plants. The second experiment focused on comparing the timing in cycle plants (phenological phases) of foliar protector application in two different bean cultivars (BRS Fc 104 and BRS MG Realce) under field conditions. Artificial shading provided better results for photosynthesis, transpiration, growth and production compared to the application of foliar protector. In the field conditions experiment, the application timing of the foliar protector at different phenological phases did not increase productivity in the cultivars. The application of foliar protector under the conditions studied was not effective in mitigating the negative impacts of high solar radiation and temperature on common bean cultivation. However, it is opportune to evaluate the application of foliar protector in bean plants grown under conditions with water deficit, high solar radiation and high temperature. [ABSTRACT FROM AUTHOR]

Featured Application: The valorization of grape- and tomato-derived extracts and/or bioactives, with anti-inflammatory and antioxidant properties, as bio-functional ingredients of anti-UV sun oils for skin protection. Daily exposure to solar light is not so harmless as previously thought, since UVA and UVB radiation has a significant effect on human health, by inducing skin-related inflammatory manifestations, such as hyperpigmentation, dermatitis, premature aging, erythema, and sunburn, among the most common skin conditions. At the same time, irreversible diseases such as various types of skin cancers, like basal cell carcinoma, melanoma, and squamous cell carcinoma, have begun to increase at dramatic rates, due to inflammatory and oxidative malignant effects of UV radiation exposure. Within this article, the health promoting effects of sunscreen for skin protection and especially of sunscreen enriched with natural antioxidant, anti-inflammatory, anti-allergic, and anti-cancer bio-functional ingredients are thoroughly reviewed. Emphasis is given to bioactives from grape by-products, such as bio-functional phytochemicals like flavonoids, stilbenes, and phenolic acids, as well as to tomato-derived bioactives like lycopene, which act either solely or synergistically and significantly enhance the antioxidant capacity of the composition product, as well as its photo-protection. The promising outcomes from in vitro studies and those reported from in vivo approaches, as well as the mechanisms of the obtained antioxidant, anti-inflammatory, anti-thrombotic, and antitumor action(s) of sunscreens infused with such natural bioactives, are also outlined. Limitations, such as the difficulties in incorporating lipophilic compounds like lycopene and/or amphiphilic phenolics into sunscreen cosmetic formulations, as well as future perspectives on the overall benefits that these compounds give to sunscreens, helping to improve properties such as smell, color, homogeneity, water resistance, and especially the Sun Protection Factor (SPF), are also discussed. [ABSTRACT FROM AUTHOR]

The thermal tolerance of symbiodiniacean photo-endosymbionts largely underpins the thermal bleaching resilience of their cnidarian hosts such as corals and the coral model Exaiptasia diaphana. While variation in thermal tolerance between species is well documented, variation between conspecific strains is understudied. We compared the thermal tolerance of three closely related strains of Breviolum minutum represented by two internal transcribed spacer region 2 profiles (one strain B1–B1o–B1g–B1p and the other two strains B1–B1a–B1b–B1g) and differences in photochemical and non-photochemical quenching, de-epoxidation state of photopigments, and accumulation of reactive oxygen species under rapid short-term cumulative temperature stress (26–40 °C). We found that B. minutum strains employ distinct photoprotective strategies, resulting in different upper thermal tolerances. We provide evidence for previously unknown interdependencies between thermal tolerance traits and photoprotective mechanisms that include a delicate balancing of excitation energy and its dissipation through fast relaxing and state transition components of non-photochemical quenching. The more thermally tolerant B. minutum strain (B1–B1o–B1g–B1p) exhibited an enhanced de-epoxidation that is strongly linked to the thylakoid membrane melting point and possibly membrane rigidification minimizing oxidative damage. This study provides an in-depth understanding of photoprotective mechanisms underpinning thermal tolerance in closely related strains of B. minutum. [ABSTRACT FROM AUTHOR]

AbstractOxygenic photosynthesis in microalgae and cyanobacteria is considered an important chassis to accelerate energy transition and mitigate global warming. Currently, cultivation systems for photosynthetic microbes for large-scale applications encountered excessive light exposure stress. High light stress can: affect photosynthetic efficiency, reduce productivity, limit cell growth, and even cause cell death. Deciphering photoprotection mechanisms and constructing high-light tolerant chassis have been recent research focuses. In this review, we first briefly introduce the self-protection mechanisms of common microalgae and cyanobacteria in response to high light stress. These mechanisms mainly include: avoiding excess light absorption, dissipating excess excitation energy, quenching excessive high-energy electrons, ROS detoxification, and PSII repair. We focus on the species-specific differences in these mechanisms as well as recent advancements. Then, we review engineering strategies for creating high-light tolerant chassis, such as: reducing the size of the light-harvesting antenna, optimizing non-photochemical quenching, optimizing photosynthetic electron transport, and enhancing PSII repair. Finally, we propose a comprehensive exploration of mechanisms: underlying identified high light tolerant chassis, identification of new genes pertinent to high light tolerance using innovative methodologies, harnessing CRISPR systems and artificial intelligence for chassis engineering modification, and introducing plant photoprotection mechanisms as future research directions. [ABSTRACT FROM AUTHOR]

Summary: Diatoms are a diverse group of phytoplankton usually dominating areas characterized by rapidly shifting light conditions. Because of their high growth rates and interesting biochemical profile, their biomass is considered for various commercial applications. This study aimed at identifying strains with superior growth in a photobioreactor (PBR) by screening the natural intraspecific diversity of ecotypes isolated from different habitats. We investigated the effect of PBR light fluctuating on a millisecond scale (FL, simulating the light in a PBR) on 19 ecotypes of the diatom Skeletonema marinoi isolated from the North Sea–Baltic Sea area.We compare growth, pigment ratios, phylogeny, photo‐physiological variables and photoacclimation strategies between all strains and perform qPCR and absorption spectra analysis on a subset of strains.Our results show that the ecotypes responded differently to FL, and have contrasting photo‐physiological and photoprotective strategies. The strains from Kattegat performed better in FL, and shared common photoacclimation and photoprotection strategies that are the results of adaptation to the specific light climate of the Kattegat area.The strains that performed better with FL conditions had a high light (HL)‐acclimated phenotype coupled with unique nonphotochemical quenching features. Based on their characteristics, three strains were identified as good candidates for growth in PBRs. [ABSTRACT FROM AUTHOR]

Background: Photoprotection is the first measure in the prevention and treatment of the deleterious effects that sunlight can cause on the skin. It is well known that prolonged exposure to solar radiation leads to acute and chronic complications, such as erythema, accelerated skin aging, proinflammatory and procarcinogenic effects, and eye damage, among others. Methods: A better understanding of the molecules that can protect against ultraviolet radiation and their effects will lead to improvements in skin health. Results: Most of these effects of the sunlight are modulated by oxidative stress and proinflammatory mechanisms, therefore, the supplementation of substances that can regulate and neutralize reactive oxygen species would be beneficial for skin protection. Current evidence indicates that systemic photoprotection should be used as an adjunctive measure to topical photoprotection. Conclusion: Oral photoprotectors are a promising option in improving protection against damage induced by UVR, as they contain active ingredients that increase the antioxidant effects of the body, complementing other photoprotection measures. We present a review of oral photoprotectors and their effects. [ABSTRACT FROM AUTHOR]

Many individuals with vitiligo are uncertain about their skin cancer risk, phototherapy risks, and recommended sun protective practices. This study examined the perceived skin cancer risk and sun protective practices among individuals living with vitiligo. A secondary objective was to understand where participants obtain this information. This was a prospective cross-sectional study. An online survey was distributed to vitiligo support group leaders globally who shared the survey with their members. Individuals over the age of 18 and with vitiligo were included. There were 209 survey respondents, the majority were between the ages 35–54 (45.5%, n = 95), female (70.8%, n = 148), White (66.0%, n = 138). Nearly half of respondents believed they were at increased risk of skin cancer because of their vitiligo (45.5%, n = 95) and nearly a quarter (22.5%, n = 47) believed that phototherapy increased their risk of skin cancer. Having vitiligo affected sun protective practices with less than a quarter (24.4%, n = 51) of respondents using sunscreen daily or often prior to their vitiligo diagnosis in comparison to the majority of respondents (60.3%, n = 126) using it after their vitiligo diagnosis. The three most common sources where patients obtained information were the internet and social media (46.4%, n = 97), vitiligo support groups (23.4%, n = 49), and dermatologists (20.6%, n = 43). Despite evidence indicating a decreased risk of skin cancer in individuals with vitiligo and supporting the safety of narrowband ultraviolet B phototherapy, many participants believed they were at an increased risk of skin cancer. Findings were sub-stratified and showed differences in sunscreen usage based on gender, skin color, and percent depigmentation. This study also found nearly half of respondents obtained information related to vitiligo from the internet and social media. The number of participants may limit the generalizability of the findings. Survey questionnaires are also subject to response bias. The findings from this study highlight demographic variations in sunscreen usage which may help guide the development of targeted interventions to improve sun protective behaviors among diverse populations with vitiligo. In addition, this study suggests certain sun protective practices and skin cancer risk perceptions may vary based on extent of depigmentation. Lastly, this study also demonstrates the internet and social media as a popular source for obtaining information, emphasizing the need for dermatologists to leverage various online communication channels to help disseminate accurate information. [ABSTRACT FROM AUTHOR]

In plants, secondary metabolites change in response to environmental conditions. These changes co-regulate resilience to stressful environmental conditions, plant growth and development, and interactions between plants and the wider ecosystem, while also affecting soil carbon storage and atmospheric and climatic conditions. The objective of this study was to determine the association between UV exposure and the contents of key metabolites, including amino acids, phenolics, flavonoids, terpenoids, carotenoids, tocopherols, and phytosterols. Mentha spicata plantlets were grown in tissue culture boxes for 30 days and then exposed to a low dose of broadband UV-B (291–315 nm; 2.8 kJm−2 biologically effective UV) enriched light for eight days. Metabolite contents were quantified either immediately after the final UV exposure, or after seven days of recovery under photosynthetically active radiation. It was found that UV promoted the production of flavonoids (1.8-fold) ahead of phenolic acids (unchanged). Furthermore, the majority of monoterpenes and sesquiterpenes, constituents of valuable mint essential oil, were significantly increased through UV treatment (up to 90-fold for α-linalool). In contrast, the contents of carotenoids and tocopherols did not increase following UV exposure. A comparison between plants sampled immediately after UV exposure and after seven days of recovery showed that there was an overall increase in the content of carotenoids, mono- and sesquiterpenes, phenolics, and amino acids following recovery, while the contents of sterols and tocopherols decreased. These UV-induced changes in metabolite profile may have important consequences for agriculture, ecology, and even the global climate, and they also provide an exciting opportunity to enhance crop value, facilitating the development of improved products with higher levels of essential oils and added benefits of enhanced flavour, colour, and bioactive content. [ABSTRACT FROM AUTHOR]