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Haematococcus lacustris is an important species of green algae because it produces the high-value carotenoid astaxanthin. Astaxanthin production is enhanced by various stress conditions causing the transformation of green vegetative cells to red cells with high amounts of astaxanthin, which plays various photoprotective and antioxidant roles. Although intensive research has been conducted to reveal the regulation of astaxanthin production, the photosynthetic capacity of the various cell forms is unresolved at the single-cell level. In this work, we characterized the photosynthetic and morphological changes of Haematococcus cells, using a combination of microfluidic tools and microscopic chlorophyll fluorescence imaging. We found marked but reversible changes in the variable chlorophyll fluorescence signatures upon the transformation of green cells to red cells, and we propose that the photosynthetic activity as revealed by single-cell chlorophyll fluorescence kinetics serves as a useful phenotypic marker of the different cell forms of Haematococcus.

The review highlights the relationship between the molecular organization of the light-harvesting complex of photosystem II (LHCII) and sunlight utilization by higher plants. The molecular form of LHCII switches rapidly and reversibly during diurnal changes of light intensity, from low (ca. 10) to high [ca. 1,000 µmol(photon) m-2 s-1], so the sensitivity of LHCII to light may control the balance between light harvesting and photoprotection state. Our understanding and concept of this mechanism are based on the knowledge of the structure and photophysics of different LHCII molecular forms: monomer, dimer, trimer, and aggregate. It is proposed that LHCII monomers, dimers, and lateral aggregates are fundamental blocks of excess light-dissipation machinery. Trimer is exceptionally well suited to play a physiological role of an antenna complex. A correlation between the LHCII molecular form and the presence of xanthophyll cycle pigment violaxanthin and zeaxanthin in the complex structure is also shown. Moreover, the role of LHCII protein phosphorylation in thylakoid membrane architecture is also discussed. The dual function of LHCII has been studied in the natural thylakoid membranes of chloroplasts, in the artificial lipid-LHCII model membranes, and by suspension of LHCII in a detergent solution.

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.

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.

Photosynthetic organisms use sunlight as the primary energy source to fix CO2 . However, in nature, light energy is highly variable, reaching levels of saturation for periods ranging from milliseconds to hours. In the green microalga Chlamydomonas reinhardtii, safe dissipation of excess light energy by nonphotochemical quenching (NPQ) is mediated by light-harvesting complex stress-related (LHCSR) proteins and redistribution of light-harvesting antennae between the photosystems (state transition). Although each component underlying NPQ has been documented, their relative contributions to NPQ under fluctuating light conditions remain unknown. Here, by monitoring NPQ in intact cells throughout high light/dark cycles of various illumination periods, we find that the dynamics of NPQ depend on the timescales of light fluctuations. We show that LHCSRs play a major role during the light phases of light fluctuations and describe their role in growth under rapid light fluctuations. We further reveal an activation of NPQ during the dark phases of all high light/dark cycles and show that this phenomenon arises from state transition. Finally, we show that LHCSRs and state transition synergistically cooperate to enable NPQ response during light fluctuations. These results highlight the dynamic functioning of photoprotection under light fluctuations and open a new way to systematically characterize the photosynthetic response to an ever-changing light environment.

Desiccation tolerance in vegetative tissues enables resurrection plants to remain quiescent under severe drought and rapidly recover full metabolism once water becomes available. Barbacenia graminifolia is a resurrection plant that occurs at high altitudes, typically growing on rock slits, exposed to high irradiance and limited water availability. We analyzed the levels of reactive oxygen species (ROS) and antioxidants, carotenoids and its cleavage products, and stress-related phytohormones in fully hydrated, dehydrated, and rehydrated leaves of B. graminifolia. This species exhibited a precise adjustment of its antioxidant metabolism to desiccation. Our results indicate that this adjustment is associated with enhanced carotenoid and apocarotenoids, α-tocopherol and compounds of ascorbate-glutathione cycle. While a-carotene and lutein increased in dried-leaves suggesting effective protection of the lightharvesting complexes, the decrease in β-carotene was accompanied of 10.2-fold increase in the content of β-cyclocitral, an apocarotenoid implicated in the regulation of abiotic stresses, compared to hydrated plants. The principal component analysis showed that dehydrated plants at 30 days formed a separate cluster from both hydrated and dehydrated plants for up to 15 days. This regulation might be part of the protective metabolic strategies employed by this resurrection plant to survive water scarcity in its inhospitable habitat. [ABSTRACT FROM AUTHOR]

Introduction: Global climate change exerts a significant impact on the nitrogen supply and photosynthesis ability in land-based plants. The photosynthetic capacity of dominant grassland species is important if we are to understand carbon cycling under climate change. Drought stress is one of the major factors limiting plant photosynthesis, and nitrogen (N) is an essential nutrient involved in the photosynthetic activity of leaves. The regulatory mechanisms responsible for the effects of ammonium (NH4-) and nitrate (NO3-) on the drought-induced photoinhibition of photosystem II (PSII) in plants have yet to be fully elucidated. Therefore, there is a significant need to gain a better understanding of the role of electron transport in the photoinhibition of PSII. Methods: In the present study, we conducted experiments with normal watering (LD), severe drought (MD), and extreme drought (HD) treatments, along with no nitrogen (N0), ammonium (NH4), nitrate (NO3), and mixed nitrogen (NH4NO3) treatments. We analyzed pigment accumulation, reactive oxygen species (ROS) accumulation, photosynthetic enzyme activity, photosystem activity, electron transport, and O-J-I-P kinetics. Results: Analysis showed that increased nitrate application significantly increased the leaf chlorophyll content per unit area (Chlarea) and nitrogen content per unit area (Narea) (p< 0.05). Under HD treatment, ROS levels were lower in NO3-treated plants than in N0 plants, and there was no significant difference in photosynthetic enzyme activity between plants treated with NO3 and NH4NO3. Under drought stress, the maximum photochemical efficiency of PSII (Fv/Fm), PSII electron transport rate (ETR), and effective quantum yield of PSII (ϕPSII) were significant higher in NO3-treated plants (p< 0.05). Importantly, the K-band and G-band were higher in NO3-treated plants. Discussion: These results suggest that drought stress hindered the formation of NADPH and ATP in N0 and NH4-treated L. chinensis plants, thus damaging the donor side of the PSII oxygen-evolving complex (OEC). After applying nitrate, higher photosynthetic enzyme and antioxidant enzyme activity not only protected PSII from photodamage under drought stress but also reduced the rate of damage in PSII during the growth of L. chinensis growth under drought stress. [ABSTRACT FROM AUTHOR]

This study confirms for the first time that the significant red coloration of Euglena gracilis is induced by bonito stock (BS), a traditional Japanese food, and intense red light exposure (605~660 nm, 1000~1300 µmol photons/m2/s). Under the condition, excessive photosynthetic activity destroyed many chloroplasts, while carotenoids were maintained, resulting in the formation of reddened cells. The HPLC analysis revealed that diadinoxanthin was the primary carotenoid present in reddened cells. Additionally, an undefined xanthophyll, not produced under normal culture conditions, was synthesized and suggested to contain a C=O bond. While it has been reported that strong light stress can increase the total carotenoid content of cells, this study did not verify this claim, and it should be investigated further in future research. Under white light irradiation conditions (90 μmol photons/m2/s) in BS medium, no reddening of cells was observed, and good growth was achieved (over four times the cell density in CM medium in the seventh incubation). This cell suspension is considered to have a high nutritional value because it is composed of functional food, BS and E. gracilis. The fact that this method does not involve genetic modification suggests the possibility of industrial applications, including food use, even in reddened cells. [ABSTRACT FROM AUTHOR]

Introduction: People with Xeroderma Pigmentosum (XP) have a heightened sensitivity to ultraviolet radiation (UVR) and are advised to wear photoprotective clothing including a visor covering the face and neck. Photoprotective visors are homemade and predominately worn by children with decreasing frequency as age increases. To improve upon the current design and efficacy we were tasked with developing a prototype visor to meet patients' needs. Methods: Adopting a codesign methodology, patients' experiences of wearing a visor and patient and carer views of emerging prototypes were explored during interviews. A thematic analysis was conducted in parallel with data collection and themes were interpreted into design cues; desirable attributes of a visor that would counteract the negative user experiences and meet the requirements described by patients and carers. The design cues guided the iterative development of prototypes by academic engineers. Results: Twenty-four interviews were conducted with patients and carers. Thematic analysis resulted in the following five themes: Being safe from UVR exposure; self-consciousness; temperature effects; acoustic difficulties; and material properties. The following design cues were developed from the themes respectively; materials and design with high UVR protection; ability to customise with own headwear; ventilation to reduce steaming up; acoustic functionality to enable hearing and speech; foldable, portable, and easy to put on and take off. Conclusions: It is important to understand people's experiences of using medical devices to improve their safety, efficiency and user satisfaction. The user experience themes and design cues, informed the iterative development of low fidelity visor prototypes as part of a codesign process. These design cues and responses to the prototypes are guiding commercial manufacturing and regulatory approval. The visor can then be prescribed to patients, providing an equitable service of care. [ABSTRACT FROM AUTHOR]

Skin exposure to solar ultraviolet radiation and pollutants causes several skin disorders, calling for protection methods such as sunscreen application. However, common sunscreen contains chemicals that have displayed toxicity when exposed to ultraviolet radiation. Therefore, alternatives approaches have been recently developed, such as the use of natural phytochemicals as active ingredients in photoprotection preparations. Here, we review skin protection with focus on the physics of ultraviolet radiation and photoprotection by ultraviolet filters. We present sensors for measuring ultraviolet radiation and ultraviolet radiation in ecosystems. We discuss the phototoxicity of drugs, preservatives, personal care products, and pollutants. Photocarcinogenesis, photoallergy, photostability, and toxicity of sunscreen ingredients and their impacts on human health and skin, are also reviewed. We observed that phytochemicals are promising for photoprotection due to their ability to absorb photon energy, and thus act as antioxidants. [ABSTRACT FROM AUTHOR]

Given the increasing concern surrounding ultraviolet (UV) radiation-induced skin damage, there has been a rise in demand for UV filters. Currently, UV-filters are considered emerging contaminants. The extensive production and use of UV filters have led to their widespread release into the aquatic environment. Thus, there is growing concern that UV filters may bioaccumulate and exhibit persistent properties within the environment, raising several safety health concerns. Octyl-methoxycinnamate (OMC) is extensively employed as a UV-B filter in the cosmetic industry. While initially designed to mitigate the adverse photobiological effects attributed to UV radiation, the safety of OMC has been questioned with some studies reporting toxic effects on environment. The aim of this review to provide an overview of the scientific information regarding the most widely used organic UV-filter (OMC), and its effects on biodiversity and aquatic environment. [ABSTRACT FROM AUTHOR]

Under field conditions high temperatures are usually associated to high light intensity for periods of time that are getting longer because of global warming caused by climate change. These adverse conditions lead to significant reductions in yield and fruit quality in crops of great economic relevance such as citrus. In this work, the effect of high temperatures and high light intensity occurring alone or simultaneously has been studied in Carrizo citrange plants, a citrus genotype widely used as a rootstock, and the mitigating effect of kaolin (KL) evaluated. The combined stress conditions affected the plants in a unique manner at both, physiological and hormonal regulation levels, different to the effects of each individual stress. KL alleviated the deleterious effect of combined stress in different ways: (i) reducing leaf damage and abscission, (ii) improving physiological and gas exchange parameters, (iii) decreasing foliar proline content, (iv) increasing chlorophyll content, (v) preventing carotenoid degradation, and (vi) modulating levels of hormones and their precursors involved in plant responses to stress [abscisic acid (ABA), salicylic acid (SA), cinnamic acid (CA), indole-3-acetic acid (IAA), jasmonic acid (JA) and 12-oxophytodienoic acid (OPDA)]. [ABSTRACT FROM AUTHOR]

BACKGROUND: The demand for food‐based anti‐photoaging products is surging because of the rising recognition of health and beauty, as well as enhanced comprehension of the detrimental impact of ultraviolet (UV) radiation. This study aimed to investigate the potential of bioactive peptides derived from bovine elastin, specifically focusing on identifying novel elastase inhibitory peptides and assessing their photoprotective properties using bioinformatics techniques. RESULTS: A total of 48 bioactive peptides were screened in bovine elastin hydrolysate (EH) utilizing Peptide Ranker analysis. Three novel elastase inhibitory peptides, GAGQPFPI, FFPGAG and FPGIG (in descending order of activity), exhibited potent inhibitory effects on elastase in vitro, surpassing the inhibitory effect of EH by a factor of 1–2 and reaching significantly lower concentrations (8–15 times lower) than EH. The cumulative inhibitory effect of GAGQPFPI, FFPGAG, and FPGIG reached 91.5%. Further analysis revealed that FFPGAG and FPGIG exhibited mixed inhibition, whereas GAGQPFPI displayed non‐competitive inhibition. Molecular simulations showed that these peptides interacted effectively with the elastase active site through hydrogen bonding and hydrophobic interactions. Furthermore, GAGQPFPI, FFPGAG, and FPGIG demonstrated high stability in gastrointestinal digestion, demonstrated transcellular permeability across Caco‐2 cell monolayers, and exhibited remarkable photoprotective properties against UVB‐irradiated HaCaT cells. CONCLUSION: GAGQPFPI showed the most promising potential as a functional food with photoprotective effects against UVB damage and inhibitory properties against elastase. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Interest in Antarctic fungi has grown due to their resilience in harsh environments, suggesting the presence of valuable compounds from its organisms, such as those presenting photoprotective potential, since this environment suffers the most dangerous UV exposure in the world. Therefore, this research aimed to assess the photoprotective potential of compounds from sustainable marine sources, specifically seaweed-derived fungi from Antarctic continent. These studies led to discovery of photoprotective and antioxidant properties of metabolites from Arthrinium sp., an endophytic fungus from Antarctic brown algae Phaeurus antarcticus. From crude extract, fractions A-I were obtained and compounds 1–6 isolated from E and F fractions, namely 3-Hydroxybenzyl alcohol (1), (-)-orthosporin (2), norlichexanthone (3), anomalin B (4), anomalin A (5), and agonodepside B (6). Compounds 1, 2, and 6 were not previously reported in Arthrinium. Fraction F demonstrated excellent absorbance in both UVA and UVB regions, while compound 6 exhibited lower UVB absorbance, possibly due to synergistic effects. Fraction F and compound 6 displayed photostability and were non-phototoxic to HaCaT cells. They also exhibited antioxidant activity by reducing intracellular ROS production induced by UVA in keratinocyte monolayers and reconstructed human skin models (resulting in 34.6% and 30.2% fluorescence reduction) and did not show irritation potential in HET-CAM assay. Thus, both are promising candidates for use in sunscreens. It is noted that Fraction F does not require further purification, making it advantageous, although clinical studies are necessary to confirm its potential applicability for sunscreen formulations. [ABSTRACT FROM AUTHOR]

Background: Photoprotection is crucial in preventing the development and progression of various skin diseases. However, patients with skin disease have limited awareness of photoprotection. We evaluated the knowledge and behavioral patterns of photoprotection among Koreans with skin diseases. Methods: A cross‐sectional study was conducted in 11 general hospitals across South Korea. The study population consisted of patients aged 19 years or older who visited dermatologic clinics for their skin diseases. A self‐administered questionnaire was used to collect patient demographics, knowledge of photoprotection, and photoprotective habits. Results: In this study, 1173 patients with skin cancer, hyperpigmentary disorders, hypopigmentary disorders, or other skin diseases participated. Females scored significantly higher in knowledge of photoprotection compared to males (mean score 8.4 vs. 7.8; p <.001), and younger patients (<50 years) scored higher than older patients (mean score 8.7 vs. 7.5; p <.001). Males also reported longer sun exposure times and lower usage of photoprotective measures (both p <.001). Patients with skin cancer had the lowest mean knowledge score (7.1 ± 2.6) and were less likely to use photoprotective measures compared to other groups (p <.001). In contrast, patients with hyperpigmentation actively avoided sun exposure compared with other groups (p < 0.001). Conclusions: Knowledge of photoprotection among Korean patients with skin diseases varied depending on the gender, age, and type of skin disease. Their photoprotective behaviors were inadequate, especially among males and those with skin cancer. These findings emphasize the importance of educating and tailoring photoprotection strategies for patients with skin diseases. [ABSTRACT FROM AUTHOR]

Background: In this article, we review and discuss the photoprotection behavior of Asians based on the literature, along with a subanalysis of an original online survey, and make recommendations to optimize photoprotection for Asian populations to prevent photoaging and pigmentary disorders. Methods: An international panel of eight dermatologists from Asia (China, Korea, Japan, Singapore, Indonesia, and Vietnam) met to discuss sunscreen photoprotection for Asian patients. Additionally, a subanalysis of an online survey by 3000 respondents from three Asian countries (China, Indonesia, and Japan) investigated general public awareness and attitudes to sun exposure. Results: A pre‐meeting survey of the eight experts from Asia showed key concerns of Asian patients consulting dermatologists are pigmentary disorders, especially actinic/senile lentigo, post‐inflammatory hyperpigmentation, melasma, vitiligo, and Hori's nevus. The survey subanalysis of participants from China, Indonesia, and Japan with predominantly Fitzpatrick skin types (FST) II to IV revealed that they are particularly concerned about sun exposure causing photoaging and pigmentary disorders. Most of the respondents indicated they have limited knowledge on sunlight radiation and appropriate sunscreen protection factors. Only 22%, 13%, and 3% for China, Indonesia, and Japan, respectively, systematically use multiple protective measures (using sunscreen, avoiding midday sun, staying in the shade, wearing a hat, protective clothing, and sunglasses) when exposed to the sun. Conclusions: Further education is needed for Asian populations on the importance of comprehensive daily photoprotection, including broad‐spectrum sunscreen, with high UVA and visible light protection, to reduce and prevent photoaging and pigmentary disorders. [ABSTRACT FROM AUTHOR]

Objective: This survey aimed to evaluate knowledge of photoprotection among individuals from a random group in a resort town in Poland, Kołobrzeg, and explore the correlation between their knowledge and demographics like age, gender, education, and residence. Methods: An anonymous survey was conducted among a diverse group. This population comprised individuals from various backgrounds: health spa patients undergoing treatments, therapies and medical appointments, guests visiting the resort for leisure, passersby, and staff working at the spa and recreational facilities. The survey was designed by authors, encompassed 16 questions about knowledge on photoprotection, sunscreen use and related topics, and gathered demographic data. Responses from 142 individuals were statistically analyzed using PQStat Software. Results: Only 7.7% use sunscreen all year‐round. The majority apply sun protection factor (SPF) creams on sunny days or with prolonged sun exposure. Over half of the respondents (53.5%) are aware when to apply sunscreen but 43% reapply it less than every 4 h. 25.4% do not reapply at all. 38.7% think protection provided by higher SPF means longer sun exposure time. Over 50% believe SPF 30 offers double the protection of SPF 15. Almost half (46.8%) use extra sun protection, like sunglasses or hats. Significant correlations exist between education/age and certain survey responses. Conclusions: The findings emphasize the urgency to improve photoprotection knowledge in the Polish population, particularly regarding the year‐round harmful solar effects and the correct use of sun protection products. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the impact of diurnal and seasonal variations in photon flux density (PPFD) and air temperature on PSII efficiency in three sweet potato leaf-color cultivars: green (G), yellow-green (Y), and purple (P). The cultivars were exposed to full sunlight and measurements were taken from November to March. The maximal quantum yield of PSII photochemistry for the dark-adapted state (Fv/Fm) indicated Y's increased sensitivity to low temperatures at predawn, followed by G and P. Both quantum yield of PSII photochemistry for the dark and light- adapted state (ΔF/Fm') depressions were correlated with increased PPFD, with regression slopes in the order of Y > G > P. On high-light and low-temperature days, Fv/Fm values deviated below regression lines, with differences ranked as Y > G > P. These findings suggest that Y exhibits the highest sensitivity to high light and low temperatures, followed by G and then P in terms of PSII efficiency. [ABSTRACT FROM AUTHOR]

Fruit photosystem not only performs photosynthesis for carbon fixation but is also related to photoprotection. This study is to investigate the changes within the fruit photosystem during maturation and their possible effects in photosynthesis and photoprotection. We investigated the changes of fruit photosynthesis during the three phases (green, pink, and blue) of blueberry fruit maturation via examining CO2 gas exchange and chlorophyll fluorescence. Also, we quantified chlorophylls, carotenoids, anthocyanins, phenolics using spectrometry, and determined photosynthetic components using LC–MS/MS. As a result, fruit photosynthesis contributed in supplying a part of the carbon requirements during the maturation process. The gross photosynthetic rate in green fruit accounted for 26.36% of that in the leaf, and 15.47% and 7.59%, respectively, in pink and blue fruit. Maximum photochemical quantum yield of PSII (Fv/Fm = 0.77) in green fruit was comparable to that in leaf (0.78) and dropped to 0.65 in pink fruit (data unavailable in blue fruit). Notably, in early stage of fruit maturation, the components of photosystem reaction center (PS core), electron transport chain (ETC), and CO2 fixation were significantly downregulated, while the components in light-harvesting complex (LHC) were more highly stable than others. This led to a decrease in the ratio of PS core/LHC. Thus, more light energy absorbed by LHCs had to be dissipated as heat, since it could not be converted to chemical energy through enough PS core, ETC, and CO2 fixation. This led to an increase in non-photochemical quenching (NPQ), indicated by increased qN of 35.53%. The increased NPQ became necessary for photoprotection at the early stage of fruit maturation, while increased anthocyanin provided another kind of photoprotection at the late stage of maturation. The results suggest that the changes of photosynthetic components could be related to the transition from photosynthesis to photoprotection during fruit maturation. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV) radiation harms the skin, causing oxidative damage, inflammation, and disruption of the skin's barrier function. There is considerable interest in identifying new natural ingredients with antioxidant and anti-inflammatory properties to serve as adjuvants in sunscreens. The flavonoid morin (1) can undergo structural modifications to enhance its biological properties. The aim of this study was to synthesize two new morin-Schiff base derivatives, morin oxime (2) and morin semicarbazone (3), comparing their photoprotective effects with that of the parent compound on UVB-exposed HaCaT keratinocytes. The chemical structure of the novel compounds was revealed based on spectroscopic data analysis. Our findings demonstrated that derivatives 2 and 3 enhanced the light absorption capability in the UV–visible (vis) range compared to 1. Tested compounds exhibited a higher scavenger capacity than Trolox. Moreover, pre-treatment with all compounds protected HaCaT cells from UVB-induced cell death. Compound 3 demonstrated the strongest antioxidant effect, reducing reactive oxygen species (ROS) generation and, subsequently, malondialdehyde (MDA) levels. Additionally, compounds 2 and 3 exhibited greater anti-inflammatory effects than compound 1, significantly reducing interleukin (IL)-6 production levels at all tested concentrations. These findings have demonstrated, for the first time, a promising photoprotective activity of two new Schiff base derivatives and suggest their use as natural sunscreen ingredients. [ABSTRACT FROM AUTHOR]

One of the major threats to skin aging and the risk of developing skin cancer is excessive exposure to the sun's ultraviolet radiation (UVR). The use of sunscreens containing different synthetic, organic, and inorganic UVR filters is one of the most widespread defensive measures. However, increasing evidence suggests that some of these compounds are potentially eco-toxic, causing subtle damage to the environment and to marine ecosystems. Resorting to natural products produced in a wide range of marine species to counteract UVR-mediated damage could be an alternative strategy. The present work investigates marine-inspired thiol compounds, derivatives of ovothiol A, isolated from marine invertebrates and known to exhibit unique antioxidant properties. However, their potential use as photoprotective molecules for biocompatible sunscreens and anti-photo aging formulations has not yet been investigated. Here, we report on the UVR absorption properties, photostability, and in vitro UVA shielding activities of two synthetic ovothiol derivatives, 5-thiohistidine and iso-ovothiol A, by spectrophotometric and fluorimetric analysis. We found that the UVA properties of these compounds increase upon exposure to UVA and that their absorption activity is able to screen UVA rays, thus reducing the oxidative damage induced to proteins and lipids. The results of this work demonstrate that these novel marine-inspired compounds could represent an alternative eco-friendly approach for UVR skin protection. [ABSTRACT FROM AUTHOR]

Under controlled environmental conditions, the authors studied the effect of extended light/dark cycles of 24/12, 48/24, 96/48, and 120/60 h and continuous lighting on the content and ratio of photosynthetic and nonphotosynthetic pigments in a number of Solanaceae (eggplant (Solanum melongena L.), sweet pepper (Capsicum annuum L.), tobacco (Nicotiana tabacum L.), and tomato (Solanum lycopersicum L.)) and Brassicaceae (broccoli (Brassica oleracea var. italica Plenck), mizuna (Brassica rapa ssp nipposinica (L.H. Bailey) Hanelt), arugula (Eruca vesicaria sp. sativa Mill.), and cauliflower (Brassica oleracea L. var. botrytis L.)) plants. Plants were grown in controlled-climate chambers at 23°С and light intencity of 270 µmol/(m2 s) PAR. Control plants were grown under photoperiod of 16/8 h. Continuous lighting decreased the content of chlorophyll, its share in light-harvesting complex and chlorophyll to carotenoids ratio, but increased chlorophyll a/b ratio and the content of anthocyanins and flavonoids; these effects were differently manifested depending on plant species. At all other examined light/dark cycles (24/12, 48/24, 96/48, and 120/60 h) where average daily light integral did not differ from such under common photoperiod (16/8 h), changes in pigment complex were often observed similar to photoprotective reactions occurring upon exposure of plants to excess illumination (a decrease in the content of photosynthetic pigments, modification of their ratios, and accumulation of protective, nonphotosynthetic pigments). At the same time, plant responses were species-specific. On the whole, the obtained results have shown that changes within the plant pigment complex may be induced not only by excessive light energy coming to plants, but also by distribution of daily light integral in time as it occurs in response to abnormal light/dark cycles that, in the authors' opinion, cause a circadian asynchrony. [ABSTRACT FROM AUTHOR]

Summary: During photosynthesis, electron transport reactions generate and shuttle reductant to allow CO2 reduction by the Calvin–Benson–Bassham cycle and the formation of biomass building block in the so‐called linear electron flow (LEF). However, in nature, environmental parameters like light intensity or CO2 availability can vary and quickly change photosynthesis rates, creating an imbalance between photosynthetic energy production and metabolic needs. In addition to LEF, alternative photosynthetic electron flows are central to allow photosynthetic energy to match metabolic demand in response to environmental variations. Microalgae arguably harbour one of the most diverse set of alternative electron flows (AEFs), including cyclic (CEF), pseudocyclic (PCEF) and chloroplast‐to‐mitochondria (CMEF) electron flow. While CEF, PCEF and CMEF have large functional overlaps, they differ in the conditions they are active and in their role for photosynthetic energy balance. Here, I review the molecular mechanisms of CEF, PCEF and CMEF in microalgae. I further propose a quantitative framework to compare their key physiological roles and quantify how the photosynthetic energy is partitioned to maintain a balanced energetic status of the cell. Key differences in AEF within the green lineage and the potential of rewiring photosynthetic electrons to enhance plant robustness will be discussed. Adrien Burlacot is a finalist of the 2023 New Phytologist Tansley Medal competition for excellence in plant science. See Slater & Dolan (2023, 240: 2171–2172) for more details. [ABSTRACT FROM AUTHOR]

Summary: Induction of high photosynthetic capacity is a key acclimation response to high light (HL) for many herbaceous dicot plants; however, the signaling pathways that control this response remain largely unknown. Here, a systems biology approach was utilized to characterize the induction of high photosynthetic capacity in strongly and weakly acclimating Arabidopsis thaliana accessions.Plants were grown for 5 wk in a low light (LL) regime, and time‐resolved photosynthetic physiological, metabolomic, and transcriptomic responses were measured during subsequent exposure to HL.The induction of high nitrogen (N) assimilation rates early in the HL shift was strongly predictive of the induction of photosynthetic capacity later in the HL shift. Accelerated N assimilation rates depended on the mobilization of existing organic acid (OA) reserves and increased de novo OA synthesis during the induction of high photosynthetic capacity. Enhanced sucrose biosynthesis capacity increased in tandem with the induction of high photosynthetic capacity, and increased starch biosynthetic capacity was balanced by increased starch catabolism.This systems analysis supports a model in which the efficient induction of N assimilation early in the HL shift begins the cascade of events necessary for the induction of high photosynthetic capacity acclimation in HL. [ABSTRACT FROM AUTHOR]

Seagrasses are plants adapted to the marine environment that inhabit shallow coastal waters, where they may be exposed to direct sunlight during low tides. These plants have photoprotection mechanisms, which could include the use of phenolic secondary metabolites. In this study, rosmarinic acid (RA) and the flavonoids of Zostera noltei from the Bay of Cadiz (Spain) have been analyzed, first to define suitable conditions of leaves (i.e., fresh, dried, or frozen) for quantitative analysis, and then to explore the potential correlation between the phenolic profile of the leaves and sunlight exposure using an in situ experimental approach. Compared with fresh leaves, the contents of RA and flavonoids were significantly lower in air-dried and freeze-dried leaves. Freezing caused highly variable effects on RA and did not affect to flavonoid levels. On the other hand, the content of RA was significantly higher in plants that emerged during low tides than in plants permanently submerged, while plants underneath an artificial UV filter experienced a progressive reduction in RA content. However, the major flavonoids did not show a clear response to sunlight exposure and were unresponsive to diminished UV incidence. The results showed a positive correlation of RA with direct sunlight and UV exposure of leaves, suggesting that this compound contributes to the photoprotection of Z. noltei. [ABSTRACT FROM AUTHOR]

Objective: Sisal is a common stiff fibre produced around the world, corresponding to approximately 70% of the commercial production of all fibres of this type. The fibres are extracted from the leaves of Agave sisalana, from which approximately 4% of their weight is obtained, with the remaining 96% considered to be residues from the process of the sisal industry. The objective of this work was to obtain a polyphenol‐enriched extract from the A. sisalana residue by ultrasonically assisted extraction, characterize it chemically, evaluate in vitro antioxidant activity, and develop safe and stable photoprotective formulations for future application in cosmetic preparations. Methods: Ultrasonic extraction of solid plant material was performed using 50% ethanol/water (v/v). The extract was chemically characterized by high‐performance liquid chromatography equipment associated with classical molecular networking and evaluated for in vitro antioxidant activity by different methodologies. Ten formulations were prepared, varying the component concentrations and the shear time. The 1.0% sisal extract was incorporated into the most stable formulations, and preliminary and accelerated stability were evaluated. The emulsions were investigated for safety by assessment of primary accumulated dermal irritability and sensitization and a dermatological clinical study of phototoxicity and photosensitization. The photoprotective formulations containing or not containing the extract that were stable after 90 days had their in vivo sun protection factor (SPF), UVA protection factor, critical wavelength, and protection against visible and blue light determined. Results: Ultrasound extraction using 50% ethanol/water (EH 50) as an extractor vehicle showed the best yield. The extract exhibited a concentration of phenolic compounds (77.93 mg of equivalent to the standard gallic acid/g) and showed in vitro antioxidant activity. Emulsions without and with 1.0% sisal extract remained stable and safe. The addition of the extract to the photoprotective formulation statistically increased the SPF when compared to the formulation without the extract and offered protection against UVA radiation, critical wavelengths, and absorption of visible and blue light. Conclusion: Based on the findings, the solid residue of A. sisalana may be indicated as a component of photoprotective and antioxidant cosmetic formulations. [ABSTRACT FROM AUTHOR]

Objective: As every skin type worldwide is concerned by photoprotection, with consumers preferring cosmetic elegant and efficient sunscreen products, we aim at developing the most performant and desirable sun care products. Methods: We selected an interesting polymer, abbreviated AAHCP and designed scanning electron cryomicroscopy (cryoSEM), small angle and wide angle X‐ray scattering and confocal laser scanning microscopy studies to understand its behaviour in solution and in simplex sun care formulations. This allowed us to develop innovative sunscreen formulation technology that was demonstrated by in vitro and in vivo photoprotection methods. Comprehensive photoprotection evaluations were made on the fully developed sun protection product. Results: We observed the polymer oil structuring properties as well as its ability to form small and stable droplets in simplex emulsions. In vitro and in vivo sun protection factor (SPF) measurements demonstrated the sun protection boosting efficacy of AAHCP polymer in several emulsions or as a stand‐alone emulsifier. This formulation technology also allowed to filtering system concentration optimization. Use‐test performed on a fully developed AAHCP‐based sunscreen validated its optimal performances as well as its ideal cosmetic features, with non‐sticky, non‐greasy perception and invisible skin result. Conclusion: For the first time, thanks to a new specific polymer creating a new type of emulsion, we succeed in reconciliate in a single sun care product maximal SPF efficacy, resistance to numerous stresses and optimal sensoriality. [ABSTRACT FROM AUTHOR]

Provitamin D3 is the biological precursor to naturally formed vitamin D3 in humans, and its conversion is initiated via photoexcitation by near ultraviolet light. Following an initial photolysis, the primary intermediate, known as previtamin D3, is prone to light-induced isomerization or recyclization, which creates byproducts that limit the desired final thermal conversion to vitamin D3. The branching of the photochemical reaction is highly wavelength-dependent, whereby excitation toward the blue edge of the provitamin D3 absorption spectrum tends to terminate the reaction with the most undesired tachysterol byproduct and the lowest previtamin D3 concentration. In this work, the influence of introducing the natural amino acid phenyalanine as an excitation energy donor to the photochemical reaction is investigated. We find that the incorporation of phenylalanine into provitamin D3 solution results in greater intermediate concentrations and prolonged lifetimes of the desired previtamin D3 while simultaneously reducing the final concentration of tachysterol when exposing the solution to wavelengths at the blue edge of the provitamin D3 spectrum. The results, coupled with quantum chemical analysis, suggest that phenylalanine indeed helps to funnel energy from shorter wavelengths more effectively into the provitamin D3 precursor, while simultaneously screening those wavelengths from direct excitation, which otherwise leads to enhanced concentrations of tachysterol byproduct at the expense of previtamin D3. [ABSTRACT FROM AUTHOR]

Due to recent global warming threats, the changes in the atmosphere have caused significant ultraviolet (UV) radiation exposure, primarily emitted by the sun, which creates more awareness of photoprotection. Sunscreen development has been a convenient and crucial approach to photoprotection against ultraviolet radiation. Due to high demand, upgrading the quality of sunscreen products and certifying methods are necessary to guarantee the safety of commercial sunscreen products for use. Sunscreen products should have a satisfactory amount of sun protection factor (SPF), ultraviolet A protection factor, as well as the photostability of the sunscreens for them to be considered effective and safe for use. A rigorous study on the effectiveness of the sunscreen components and their safety standards is essential for the productive use and further improvement of the available sunscreen materials. This article summarizes the effects and issues, protective measures of sunscreen usage, and its components, mainly ultraviolet filters. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: Phytochemicals have demonstrated great potential as photoprotectants. Apple-derived compounds such as quercetin, fisetin, and rutin are reported to provide topical photoprotection, but oral delivery has not been explored. Purpose: To determine the photoprotective effects of oral administration of quercetin, fisetin, and rutin, and their accumulation in skin assessed through mass spectrometry imaging. Study design: Groups of 25 hairless mice (n = 125 mice) received in the daily feed 100 mg/kg quercetin, fisetin, or rutin, 600 mg/kg nicotinamide in water as a positive control, or no supplementation as the UV control. The animals were exposed to ultraviolet radiation (UVR) equivalent to 3.5 standard erythema doses thrice weekly. Method: Mass spectroemetry imaging was used to assess local skin accumulation. Results: Oral administration of quercetin and fisetin reduced the time to tumour onset (Quercetin: second and third tumour [p < 0.045]; fisetin: third tumour [p < 0.021]), with no observed effect for rutin. Nicotinamide delayed the onset of all three recorded tumours (p < 0.0082). Results were supported by accelerated tumour growth following quercetin treatment (p < 0.0069), whereas nicotinamide reduced tumour growth (p < 0.00015). Skin accumulation of the compounds could not be demonstrated, suggesting other mechanisms must be explored to explain these effects on UVR-induced carcinogenesis. Conclusion: Oral administration of quercetin and fisetin to hairless mice increased UVR-induced tumour development. These results indicate a need for caution when selecting candidates for photoprotectants.

IntroductionDaily solar ultraviolet (UV) radiation has an important impact on skin health. Understanding the initial events of the UV-induced response is critical to prevent deleterious conditions. However, studies in human volunteers have ethical, technical, and economic implications that make skin equivalents a valuable platform to investigate mechanisms related to UV exposure to the skin. In vitro human skin equivalents can recreate the structure and function of in vivo human skin and represent a valuable tool for academic and industrial applications. Previous studies have utilised non-pigmented full-thickness or pigmented epidermal skin equivalents to investigate skin responses to UV exposure. However, these do not recapitulate the dermal-epidermal crosstalk and the melanocyte role in photoprotection that occurs in vivo. In addition, the UV radiation used in these studies is generally not physiologically representative of real-world UV exposure.MethodsWell-characterised pigmented and non-pigmented skin equivalents that contain human dermal fibroblasts, endogenous secreted extracellular matrix proteins (ECM) and a well-differentiated and stratified epidermis have been developed. These constructs were exposed to UV radiation for ×5 consecutive days with a physiologically relevant UV dose and subsequently analysed using appropriate end-points to ascertain photodamage to the skin.ResultsWe have described that repeated irradiation of full-thickness human skin equivalents in a controlled laboratory environment can recreate UV-associated responses in vitro, mirroring those found in photoexposed native human skin: morphological damage, tanning, alterations in epidermal apoptosis, DNA lesions, proliferation, inflammatory response, and ECM-remodelling.DiscussionWe have found a differential response when using the same UV doses in non-pigmented and pigmented full-thickness skin equivalents, emphasising the role of melanocytes in photoprotection.

Background Some Sacoglossa sea slugs steal and integrate chloroplasts derived from the algae they feed on into their cells where they continue to function photosynthetically, a process termed kleptoplasty. The stolen chloroplasts – kleptoplasts – can maintain their functionality up to several months and support animal metabolism. However, chloroplast longevity can vary depending on sea slug species and algal donor. In this study, we focused on Elysia viridis, a polyphagous species that is mostly found associated with the macroalga Codium tomentosum, but that was reported to eat other macroalgae, including Chaetomorpha sp. Methods We have investigated the changes in E. viridis physiology when provided with the two different food sources to evaluate to which extent the photosynthetic and photoprotective mechanisms of the algae chloroplasts matched those of the plastids once in the animal cells. To perform the study, we rely on the evaluation of chlorophyll a variable fluorescence to study the photophysiological state of the integrated kleptoplasts and high-performance liquid chromatography (HPLC) to study variations in the photosynthetic pigments. Results We observed that the photosynthetic efficiency of E. viridis is lower when fed with Chaetomorpha. Also, significant differences were observed in the non-photochemical quenching (NPQ) abilities of the sea slugs. While sea slugs fed with C. tomentosum react similarly to high-light stress as the alga, E. viridis hosting Chaetomorpha chloroplasts were unable to properly recover from photoinhibition or perform a functional xanthophyll cycle (XC). Conclusions Our results showed that, even if the sea slugs fed with the two algae show photosynthetic activities like the respective algal donors, not all the photoprotective mechanisms present in Chaetomorpha can be maintained in E. viridis. This indicates that the functionality of the kleptoplasts does not depend solely on their origin but also on the degree of compatibility with the animal species integrating them.

BackgroundNon-melanoma skin cancer (NMSC) is the most prevalent cancer in the United States. Despite guidelines on ultraviolet (UV) avoidance, it remains difficult for people to assess their exposure, as UV is invisible and the onset of UV-induced symptoms is delayed.MethodsIn a prospective randomized trial, 97 elderly patients with a history of actinic keratoses (AK) were followed over 6 months. Fifty patients received UV counseling from a dermatologist and a wearable UV dosimeter that provided real-time and cumulative UV exposure. Forty-seven patients received only UV counseling from a dermatologist.ResultsOver 75% of participants recorded UV exposure at least once a week during the summer. After 6 months of intervention, when comparing the device group to the control group, we observed a non-significant 20% lower ratio of incidence rates of AKs (95% CI = [−41, 55%], p-value = 0.44) and a significant 95% lower ratio of incidence rates of NMSCs (95% CI = [33, 99.6%], p-value = 0.024). Surveys demonstrated that the control group’s score in self-perceived ability to participate in social activities significantly increased by 1.2 (p-value = 0.04), while in the device group, this score non-significantly decreased by 0.9 (p-value = 0.1). We did not observe changes, or between-group differences, in anxiety and depression surveys.ConclusionThis pilot clinical trial has a short duration and a small sample size. However, device adherence and quality of life questionnaires suggest a smartphone-connected wearable UV dosimeter is well accepted by an elderly population. This trial also indicates that a wearable UV dosimeter may be an effective behavioral change tool to reduce NMSC incidence in an elderly population with a prior history of AKs.Clinical trial registration: clinicaltrials.gov, identifier NCT03315286.

Abstract Background Microalgae are emerging hosts for the sustainable production of lutein, a high-value carotenoid; however, to be commercially competitive with existing systems, their capacity for lutein sequestration must be augmented. Previous attempts to boost microalgal lutein production have focussed on upregulating carotenoid biosynthetic enzymes, in part due to a lack of metabolic engineering targets for expanding lutein storage. Results Here, we isolated a lutein hyper-producing mutant of the model green microalga Chlamydomonas reinhardtii and characterized the metabolic mechanisms driving its enhanced lutein accumulation using label-free quantitative proteomics. Norflurazon- and high light-resistant C. reinhardtii mutants were screened to yield four mutant lines that produced significantly more lutein per cell compared to the CC-125 parental strain. Mutant 5 (Mut-5) exhibited a 5.4-fold increase in lutein content per cell, which to our knowledge is the highest fold increase of lutein in C. reinhardtii resulting from mutagenesis or metabolic engineering so far. Comparative proteomics of Mut-5 against its parental strain CC-125 revealed an increased abundance of light-harvesting complex-like proteins involved in photoprotection, among differences in pigment biosynthesis, central carbon metabolism, and translation. Further characterization of Mut-5 under varying light conditions revealed constitutive overexpression of the photoprotective proteins light-harvesting complex stress-related 1 (LHCSR1) and LHCSR3 and PSII subunit S regardless of light intensity, and increased accrual of total chlorophyll and carotenoids as light intensity increased. Although the photosynthetic efficiency of Mut-5 was comparatively lower than CC-125, the amplitude of non-photochemical quenching responses of Mut-5 was 4.5-fold higher than in CC-125 at low irradiance. Conclusions We used C. reinhardtii as a model green alga and identified light-harvesting complex-like proteins (among others) as potential metabolic engineering targets to enhance lutein accumulation in microalgae. These have the added value of imparting resistance to high light, although partially compromising photosynthetic efficiency. Further genetic characterization and engineering of Mut-5 could lead to the discovery of unknown players in photoprotective mechanisms and the development of a potent microalgal lutein production system.

Provitamin D3 is the biological precursor to naturally formed vitamin D3 in humans, and its conversion is initiated via photoexcitation by near ultraviolet light. Following an initial photolysis, the primary intermediate, known as previtamin D3, is prone to light-induced isomerization or recyclization, which creates byproducts that limit the desired final thermal conversion to vitamin D3. The branching of the photochemical reaction is highly wavelength-dependent, whereby excitation toward the blue edge of the provitamin D3 absorption spectrum tends to terminate the reaction with the most undesired tachysterol byproduct and the lowest previtamin D3 concentration. In this work, the influence of introducing the natural amino acid phenyalanine as an excitation energy donor to the photochemical reaction is investigated. We find that the incorporation of phenylalanine into provitamin D3 solution results in greater intermediate concentrations and prolonged lifetimes of the desired previtamin D3 while simultaneously reducing the final concentration of tachysterol when exposing the solution to wavelengths at the blue edge of the provitamin D3 spectrum. The results, coupled with quantum chemical analysis, suggest that phenylalanine indeed helps to funnel energy from shorter wavelengths more effectively into the provitamin D3 precursor, while simultaneously screening those wavelengths from direct excitation, which otherwise leads to enhanced concentrations of tachysterol byproduct at the expense of previtamin D3.

Abstract Background Systemic lupus erythematosus (SLE) is a systemic autoimmune disease that is associated with multiple organ involvement and leads to significant morbidity and mortality. One of the important environmental factors that influences the exacerbation of preexisting SLE is ultraviolet (UV) radiation, so photoprotection is essential. The aims of this study were to evaluate the accuracy and adequacy of photoprotection in pediatric SLE patients, and to investigate the effect of education on photoprotection. Methods SLE patients aged ≤ 18 years who attended pediatric outpatient clinics were prospectively enrolled. The accuracy and adequacy of photoprotection were assessed by the questionnaire, and compared between baseline and the ≥ 3-month follow-up timepoint. Comprehensive written and verbal photoprotection education was provided to all patients and parents/caregivers after the first assessment. Results One hundred patients were included (mean age 13.6 ± 2.5, 92% female). At the first assessment, 79% of patients used sunscreen with a sunburn protection factor ≥ 30 (77%) and protection grade of ultraviolet A + + + (63%). Fifty-two percent of patients applied sunscreen every day. A minority of patients applied an adequate amount of sunscreen (32%), used water-resistant sunscreen (34%), used lip balm with sunscreen (23%) and reapplied sunscreen when sweating (13%). The most commonly missed areas when applying sunscreen were the ears and dorsum of the feet. The least often practiced sun protection behavior was wearing sunglasses. The most often reported activities during the peak UV index, were playing with friends and walking to the cafeterias. At the second assessment, the majority of photoprotection practices were improved in all aspects except using water-resistant sunscreen, reapplying sunscreen when sweating, applying sunscreen on the ears and dorsum of feet, and wearing sunglasses. The main reason for not using sunscreen switched from thinking it was unnecessary at the first assessment to disliking its texture at the second assessment. Conclusions Education on photoprotection was effective in improving photoprotection practices. The photoprotection practices that need to be specifically emphasized are applying an adequate amount of sunscreen and using lip balm with sunscreen. The photoprotection which were least practiced at both the first and seconds assessments were reapplying sunscreen when sweating, applying sunscreen on the ears and dorsum of the feet, and wearing sunglasses.

Kornkanok Chaisuwannarak, Chuda Rujitharanawong, Chayada Chaiyabutr, Chanisada Wongpraprarut, Narumol Silpa-archa Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, ThailandCorrespondence: Narumol Silpa-archa, Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand, Email doctornarumol@gmail.comBackground: The COVID-19 pandemic may alter individuals’ perspectives and behaviors regarding sun exposure and photoprotection. Presently, there is a paucity of information about how the pandemic influences photoprotection in photodermatoses and melasma.Objective: To compare the photoprotection attitudes and behaviors of individuals with photodermatoses and melasma with those of a control group (other dermatologic patients) before and during the COVID-19 pandemic.Methods: A questionnaire-based, cross-sectional study was conducted among Thai patients with photodermatoses, melasma, and other dermatological conditions between August 2021 and November 2022. Each of the three groups consisted of 35 patients.Results: Among the 105 patients, 81.9% were female, and the mean age was 45.83 years. Over 80% of individuals who used surgical masks daily for 4 to 8 hours believed that these masks provided skin protection from the sun. The duration of sun exposure and the frequency of photoprotection practices decreased significantly in all groups during the COVID-19 pandemic compared to the pre-pandemic period. Sunscreen was the most prevalent form of photoprotection, but its usage declined considerably during the pandemic. Upon physical examination, the photodermatoses and control groups exhibited unchanged skin conditions, while the patients with melasma demonstrated improved skin conditions during the pandemic.Conclusion: Owing to increased indoor activities and the perception that face masks could block sunlight, the COVID-19 pandemic led to notable reductions in sun exposure and photoprotective practices. Despite the absence of photodermatoses exacerbation and the observed improvements in patients with melasma, consistent and effective photoprotection must continue to be promoted.Keywords: COVID-19 pandemic, melasma, photodermatoses, photoprotection

Yohei Tanaka,1 Richard Parker,2 Amaryllis Aganahi2 1Clinica Tanaka Plastic, Reconstructive Surgery and Anti-Aging Center, Matsumoto, Nagano, Japan; 2RATIONALE, Kyneton, VIC, AustraliaCorrespondence: Yohei Tanaka, Clinica Tanaka Plastic, Reconstructive Surgery and Anti-aging Center, M-1 Bld 1F, 3-4-3, Ote, Matsumoto, Nagano, 390-0874, Japan, Tel +81-263-36-0016, Fax +81-263-36-0016, Email info@clinicatanaka.jpBackground: Clinical, optical and histological research confirms that solar skin damage continues to pose a threat to human skin health globally despite widespread sunscreen usage and sun awareness campaigns. Despite this, very few studies examine the critical changes in gene expression and DNA repair activity following recommended topical solar protection and repair strategies to ameliorate the harmful effects of ultraviolet, visible light and near-infrared radiation.Purpose: To investigate alterations in gene expression following topical solar protection and solar repair strategies.Methods: Using epidermal keratinocytes and dermal fibroblasts derived from a 3-dimensional reconstructed human skin model, gene expression was assessed via the Genemarkers Standard Skin Panel using 112 genes deploying two analytical techniques: DNA microarray and quantitative real-time PCR exploration. Tissues were inoculated with products then collected after 24 hours following application of solar protection formulations and 16 hours following solar repair formulations (The Essential Six, RATIONALE, Victoria, Australia).Results: A DNA microarray revealed 67 genes that were significantly up-regulated or down-regulated following the treatment. The quantitative real-time PCR revealed that, in comparison to the control, the genes encoding Intercellular Adhesion Molecule 1 (ICAM1), Metallothionein 1A (MT1A), Prostaglandin-Endoperoxide Synthase 1 (PTGS2), Late Cornified Envelope 3D (LCE3D), Peroxisome Proliferator Activated Receptor (PPARD), and Granulocyte/Macrophage Colony Stimulating Factor 2 (GM-CSF2) have been up-regulated following usage of the solar protection regime, 1.87, 861.16, 4.34, 1.91, 1.06, and 3.6, respectively. ICAM1, MT1A, PTGS2, LCE3D, PPARD, and GM-CSF2 were up-regulated following use of the solar repair regime, 3.78, 2.98, 14.89, 5.09, 2.42, and 13.51, respectively.Conclusion: This study demonstrates that a specific solar protection and repair regime upregulated genes involved in photoprotection and repair mechanisms in a 3-dimensional (3D) reconstructed human-like skin model.Keywords: gene expression, anti-photoageing, anti-photoimmunosuppression, antioxidant, photoprotection, DNA repair

To explore the photosynthetic system adaptation mechanism of two dominant ephemeral plants, including Malcolmia scorpioides and Arnebia decumbens, to light and temperature, this study measured the chlorophyll fluorescence parameters and discussed their light damage and the change of photosynthetic activities under different temperatures (25-60℃) and constant room temperature (25℃) and high temperature and different illumination (80-400 μmol·m-2·s-1). The results were as follows: (1) The photosynthetic efficiency and electron transport rate increased first and then decreased with the increase of temperature, reached the highest value at 40℃ and then rapidly decreased, the quantum yield of non-regulated energy dissipation in PS Ⅱ［Y(NO)］and PS I receptor side heat dissipation efficiency［Y(NA)］increased, and the photosynthetic system was damaged due to the accumulation of excitation pressure at the receptor terminal. (2) Under the light range of 80-400 μmol·m-2·s-1 and room temperature, the photosynthetic efficiency increased with the enhancement of light intensity; under high temperature, the combined stress of light and high temperature on plants descended the photosynthetic activities of plants and the quantum yield of regulatory energy dissipation in PS Ⅱ［Y(NPQ)］, and when the light intensity reached 320 μmol·m-2·s-1, the ring electron transport flow disappeared. In conclusion, light and temperature within a certain range can improve the photosynthetic activity, activate heat dissipation and ring electron transport flow and reduced photoinhibition. However, with the increase of temperature and light intensity at high temperature, the adaptation ability of the two ephemeral plants decrease and the photoprotective mechanism disappeared. The main reason is the accumulation of PS I receptor side excitation pressure and the failure of regulatory heat dissipation.

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.

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.

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.

Cancer remains a significant global health challenge, with millions of deaths attributed to it annually. Radiotherapy, a cornerstone in cancer treatment, aims to destroy cancer cells while minimizing harm to healthy tissues. However, the harmful effects of irradiation on normal cells present a formidable obstacle. To mitigate these effects, researchers have explored using radioprotectors and mitigators, including natural compounds derived from secondary plant metabolites. This review outlines the diverse classes of natural compounds, elucidating their roles as protectants of healthy cells. Furthermore, the review highlights the potential of these compounds as radioprotective agents capable of enhancing the body’s resilience to radiation therapy. By integrating natural radioprotectors into cancer treatment regimens, clinicians may improve therapeutic outcomes while minimizing the adverse effects on healthy tissues. Ongoing research in this area holds promise for developing complementary strategies to optimize radiotherapy efficacy and enhance patient quality of life.

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.

Grape marc is a by-product resulting from the winemaking industry that still contains beneficial compounds that can be valorized. Thus, we report here the possibility of using polyphenolic extracts of grape marc origin to obtain sun protection creams. The extractions were performed in ethanol and acetone solutions using pomace from different grape varieties (Merlot, Bläufrankisch, Fetească Neagră, Isabella) as a raw material. The obtained extracts were analyzed in order to determine the total phenolic content, the antioxidant activity, and the sun protection factor (SPF) via Mansur spectrophotometric assay. The best results were achieved using 70% ethanol in water as a solvent. The extracts with the highest potential photoprotective effects are from the Merlot variety (SPFspectrophotometric = 7.83 ± 0.76). The sunscreens were prepared using the 70% ethanolic extract of the Merlot variety evaporated to dryness, redissolved in either distilled water or ethanol. The SPF estimated in vitro via the COLIPA method showed values of 14.07 ± 1.50 and 11.46 ± 1.32 for the aqueous and ethanolic extracts, respectively, when working with a cream to polyphenolic extract a ratio of 1/1 (w/w). At the same time, the use of aqueous polyphenolic extracts ensures the better stability of creams compared with the ethanolic ones.

The photosystem I (PSI) of the green alga Chlamydomonas reinhardtii associates with 10 light-harvesting proteins (LHCIs) to form the PSI-LHCI complex. In the context of state transitions, two LHCII trimers bind to the PSAL, PSAH and PSAO side of PSI to produce the PSI-LHCI-LHCII complex. In this work, we took advantage of chemical crosslinking of proteins in conjunction with mass spectrometry to identify protein–protein interactions between the light-harvesting proteins of PSI and PSII. We detected crosslinks suggesting the binding of LHCBM proteins to the LHCA1-PSAG side of PSI as well as protein–protein interactions of LHCSR3 with LHCA5 and LHCA3. Our data indicate that the binding of LHCII to PSI is more versatile than anticipated and imply that LHCSR3 might be involved in the regulation of excitation energy transfer to the PSI core via LHCA5/LHCA3.