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Photochemistry and Photobiology Jun 2024Exposure to phototoxicants and photosensitizers can result in the generation of reactive oxygen species (ROS), leading to oxidative stress, DNA damage, and various...
Exposure to phototoxicants and photosensitizers can result in the generation of reactive oxygen species (ROS), leading to oxidative stress, DNA damage, and various skin-related issues such as aging, allergies, and cancer. While several photo-protectants offer defense against ultraviolet radiation (UV-R), their effectiveness is often limited by photo-instability. Sunset Yellow (SY), an FDA-approved food dye, possesses significant UV-R and visible light absorption properties. However, its photoprotective potential has remained unexplored. Our investigation reveals that SY exhibits remarkable photostability for up to 8 h under both UV-R and sunlight. Notably, SY demonstrates the ability to quench ROS, including singlet oxygen (O), superoxide radicals ( ), and hydroxyl radicals (·OH) induced by rose bengal, riboflavin and levofloxacin, respectively. Moreover, SY proves effective in protecting against the apoptotic and necrotic cell death induced by the phototoxicant chlorpromazine (CPZ) in HaCaT cells. Further, it was observed that SY imparts photoprotection by inhibiting intracellular ROS generation and calcium release. Genotoxicity evaluation provides additional evidence supporting SY's photoprotective effects against CPZ-induced DNA damage. In conclusion, these findings underscore the potential of SY as a promising photoprotective agent against the toxic hazards induced by phototoxicants, suggesting its prospective application in the formulation of broad-spectrum sunscreens.
PubMed: 38899585
DOI: 10.1111/php.13966 -
UV protection and insecticidal activity of microencapsulated Vip3Ag4 protein in Bacillus megaterium.Toxicon : Official Journal of the... Jun 2024In this study, secretable Vip3Ag4 protein was encapsulated in Bacillus megaterium and used for quantitative bioassays, in order to determine the UV photoprotective...
In this study, secretable Vip3Ag4 protein was encapsulated in Bacillus megaterium and used for quantitative bioassays, in order to determine the UV photoprotective capacity of the cell, for preventing inactivation of the insecticidal activity of the protein. The non-encapsulated and purified protein was exposed to the UV light showing a LC of 518 ng/cm against Spodoptera littoralis larvae, whereas the exposed encapsulated protein exhibited 479 ng/cm. In addition to the capability to accumulate Vip3 proteins for the development of novel insecticidal formulates, the B. megaterium cell has demonstrated to provide moderate protection against the deleterious action of UV light.
PubMed: 38897358
DOI: 10.1016/j.toxicon.2024.107807 -
American Journal of Clinical Dermatology Jun 2024Melasma is a chronic, acquired disorder of focal hypermelanosis that carries significant psychosocial impact and is challenging for both the patient and the treating... (Review)
Review
Melasma is a chronic, acquired disorder of focal hypermelanosis that carries significant psychosocial impact and is challenging for both the patient and the treating practitioner to manage in the medium to long term. Multiple treatments have been explored, often in combination given the many aetiological factors involved in its pathogenesis. Therapeutic discoveries to treat melasma are a focal topic in the literature and include a range of modalities, with recent developments including updates on visible light photoprotection, non-hydroquinone depigmenting agents, oral tranexamic acid, chemical peels, and laser and energy-based device therapy for melasma. It is increasingly important yet challenging to remain up-to-date on the arsenal of treatments available for melasma to find an efficacious and well-tolerated option for our patients.
PubMed: 38896402
DOI: 10.1007/s40257-024-00863-2 -
Plant Cell Reports Jun 2024Saline-alkali stress induces oxidative damage and photosynthesis inhibition in H. citrina, with a significant downregulation of the expression of photosynthesis- and...
Saline-alkali stress induces oxidative damage and photosynthesis inhibition in H. citrina, with a significant downregulation of the expression of photosynthesis- and antioxidant-related genes at high concentration. Soil salinization is a severe abiotic stress that impacts the growth and development of plants. In this study, Hemerocallis citrina Baroni was used to investigate its responsive mechanism to complex saline-alkali stress (NaCl:NaSO:NaHCO:NaCO = 1:9:9:1) for the first time. The growth phenotype, photoprotective mechanism, and antioxidant system of H. citrina were studied combining physiological and transcriptomic techniques. KEGG enrichment and GO analyses revealed significant enrichments of genes related to photosynthesis, chlorophyll degradation and antioxidant enzyme activities, respectively. Moreover, weighted gene co-expression network analysis (WGCNA) found that saline-alkali stress remarkably affected the photosynthetic characteristics and antioxidant system. A total of 29 key genes related to photosynthesis and 29 key genes related to antioxidant enzymes were discovered. High-concentration (250 mmol L) stress notably inhibited the expression levels of genes related to light-harvesting complex proteins, photosystem reaction center activity, electron transfer, chlorophyll synthesis, and Calvin cycle in H. citrina leaves. However, most of them were insignificantly changed under low-concentration (100 mmol L) stress. In addition, H. citrina leaves under saline-alkali stress exhibited yellow-brown necrotic spots, increased cell membrane permeability and accumulation of reactive oxygen species (ROS) as well as osmolytes. Under 100 mmol L stress, ROS was eliminate by enhancing the activities of antioxidant enzymes. Nevertheless, 250 mmol L stress down-regulated the expression levels of genes encoding antioxidant enzymes, and key enzymes in ascorbate-glutathione (AsA-GSH) cycle as well as thioredoxin-peroxiredoxin (Trx-Prx) pathway, thus inhibiting the activities of these enzymes. In conclusion, 250 mmol L saline-alkali stress caused severe damage to H. citrina mainly by inhibiting photosynthesis and ROS scavenging capacity.
Topics: Photosynthesis; Antioxidants; Gene Expression Regulation, Plant; Stress, Physiological; Chlorophyll; Alkalies; Plant Leaves; Salt Stress; Oxidative Stress
PubMed: 38896259
DOI: 10.1007/s00299-024-03261-4 -
Molecules (Basel, Switzerland) Jun 2024Chamazulene (CA) is an intensely blue molecule with a wealth of biological properties. In cosmetics, chamazulene is exploited as a natural coloring and soothing agent....
Chamazulene (CA) is an intensely blue molecule with a wealth of biological properties. In cosmetics, chamazulene is exploited as a natural coloring and soothing agent. CA is unstable and tends to spontaneously degrade, accelerated by light. We studied the photodegradation of CA upon controlled exposure to UVB-UVA irradiation by multiple techniques, including GC-MS, UHPLC-PDA-ESI-MS/MS and by direct infusion in ESI-MS, which were matched to in silico mass spectral simulations to identify degradation products. Seven byproducts formed upon UVA exposure for 3 h at 70 mW/cm (blue-to-green color change) were identified, including CA dimers and CA benzenoid, which were not found on extended 6 h irradiation (green-to-yellow fading). Photostability tests with reduced irradiance conducted in various solvents in the presence/absence of air indicated highest degradation in acetonitrile in the presence of oxygen, suggesting a photo-oxidative mechanism. Testing in the presence of antioxidants (tocopherol, ascorbyl palmitate, hydroxytyrosol, bakuchiol, γ-terpinene, TEMPO and their combinations) indicated the highest protection by tocopherol and TEMPO. Sunscreens ethylhexyl methoxycinnamate and particularly Tinosorb S (but not octocrylene) showed good CA photoprotection. Thermal stability tests indicated no degradation of CA in acetonitrile at 50 °C in the dark for 50 days; however, accelerated degradation occurred in the presence of ascorbyl palmitate.
Topics: Azulenes; Oils, Volatile; Oxidation-Reduction; Photolysis; Ultraviolet Rays; Antioxidants; Achillea; Artemisia; Tandem Mass Spectrometry; Gas Chromatography-Mass Spectrometry
PubMed: 38893479
DOI: 10.3390/molecules29112604 -
International Journal of Molecular... May 2024Nanotechnology is revolutionizing fields of high social and economic impact. such as human health preservation, energy conversion and storage, environmental... (Review)
Review
Nanotechnology is revolutionizing fields of high social and economic impact. such as human health preservation, energy conversion and storage, environmental decontamination, and art restoration. However, the possible global-scale application of nanomaterials is raising increasing concerns, mostly related to the possible toxicity of materials at the nanoscale. The possibility of using nanomaterials in cosmetics, and hence in products aimed to be applied directly to the human body, even just externally, is strongly debated. Preoccupation arises especially from the consideration that nanomaterials are mostly of synthetic origin, and hence are often seen as "artificial" and their effects as unpredictable. Melanin, in this framework, is a unique material since in nature it plays important roles that specific cosmetics are aimed to cover, such as photoprotection and hair and skin coloration. Moreover, melanin is mostly present in nature in the form of nanoparticles, as is clearly observable in the ink of some animals, like cuttlefish. Moreover, artificial melanin nanoparticles share the same high biocompatibility of the natural ones and the same unique chemical and photochemical properties. Melanin is hence a natural nanocosmetic agent, but its actual application in cosmetics is still under development, also because of regulatory issues. Here, we critically discuss the most recent examples of the application of natural and biomimetic melanin to cosmetics and highlight the requirements and future steps that would improve melanin-based cosmetics in the view of future applications in the everyday market.
Topics: Melanins; Humans; Hair Color; Animals; Cosmetics; Nanoparticles; Skin Pigmentation; Nanostructures; Nanotechnology
PubMed: 38892049
DOI: 10.3390/ijms25115862 -
International Journal of Molecular... May 2024Photosystem II (PSII) functions were investigated in basil ( L.) plants sprayed with 1 mM salicylic acid (SA) under non-stress (NS) or mild drought-stress (MiDS)...
Photosystem II (PSII) functions were investigated in basil ( L.) plants sprayed with 1 mM salicylic acid (SA) under non-stress (NS) or mild drought-stress (MiDS) conditions. Under MiDS, SA-sprayed leaves retained significantly higher (+36%) chlorophyll content compared to NS, SA-sprayed leaves. PSII efficiency in SA-sprayed leaves under NS conditions, evaluated at both low light (LL, 200 μmol photons m s) and high light (HL, 900 μmol photons m s), increased significantly with a parallel significant decrease in the excitation pressure at PSII (1-) and the excess excitation energy (EXC). This enhancement of PSII efficiency under NS conditions was induced by the mechanism of non-photochemical quenching (NPQ) that reduced singlet oxygen (O) production, as indicated by the reduced quantum yield of non-regulated energy loss in PSII (Φ). Under MiDS, the thylakoid structure of water-sprayed leaves appeared slightly dilated, and the efficiency of PSII declined, compared to NS conditions. In contrast, the thylakoid structure of SA-sprayed leaves did not change under MiDS, while PSII functionality was retained, similar to NS plants at HL. This was due to the photoprotective heat dissipation by NPQ, which was sufficient to retain the same percentage of open PSII reaction centers (q), as in NS conditions and HL. We suggest that the redox status of the plastoquinone pool (q) under MiDS and HL initiated the acclimation response to MiDS in SA-sprayed leaves, which retained the same electron transport rate (ETR) with control plants. Foliar spray of SA could be considered as a method to improve PSII efficiency in basil plants under NS conditions, at both LL and HL, while under MiDS and HL conditions, basil plants could retain PSII efficiency similar to control plants.
Topics: Photosystem II Protein Complex; Salicylic Acid; Ocimum basilicum; Droughts; Plant Leaves; Stress, Physiological; Chlorophyll; Photosynthesis; Thylakoids; Light
PubMed: 38891916
DOI: 10.3390/ijms25115728 -
International Journal of Molecular... May 2024Photoprotective properties of 1,25-dihydroxyvitamin D (1,25(OH)D) to reduce UV-induced DNA damage have been established in several studies. UV-induced DNA damage in skin...
Photoprotective properties of 1,25-dihydroxyvitamin D (1,25(OH)D) to reduce UV-induced DNA damage have been established in several studies. UV-induced DNA damage in skin such as single or double strand breaks is known to initiate several cellular mechanisms including activation of poly(ADP-ribose) (pADPr) polymerase-1 (PARP-1). DNA damage from UV also increases extracellular signal-related kinase (ERK) phosphorylation, which further increases PARP activity. PARP-1 functions by using cellular nicotinamide adenine dinucleotide (NAD+) to synthesise pADPr moieties and attach these to target proteins involved in DNA repair. Excessive PARP-1 activation following cellular stress such as UV irradiation may result in excessive levels of cellular pADPr. This can also have deleterious effects on cellular energy levels due to depletion of NAD+ to suboptimal levels. Since our previous work indicated that 1,25(OH)D reduced UV-induced DNA damage in part through increased repair via increased energy availability, the current study investigated the effect of 1,25(OH)D on UV-induced PARP-1 activity using a novel whole-cell enzyme- linked immunosorbent assay (ELISA) which quantified levels of the enzymatic product of PARP-1, pADPr. This whole cell assay used around 5000 cells per replicate measurement, which represents a 200-400-fold decrease in cell requirement compared to current commercial assays that measure in vitro pADPr levels. Using our assay, we observed that UV exposure significantly increased pADPr levels in human keratinocytes, while 1,25(OH)D significantly reduced levels of UV-induced pADPr in primary human keratinocytes to a similar extent as a known PARP-1 inhibitor, 3-aminobenzamide (3AB). Further, both 1,25(OH)D and 3AB as well as a peptide inhibitor of ERK-phosphorylation significantly reduced DNA damage in UV-exposed keratinocytes. The current findings support the proposal that reduction in pADPr levels may be critical for the function of 1,25(OH)D in skin to reduce UV-induced DNA damage.
Topics: Humans; Ultraviolet Rays; Poly (ADP-Ribose) Polymerase-1; Vitamin D; DNA Damage; Keratinocytes; Calcitriol; DNA Repair; Phosphorylation
PubMed: 38891771
DOI: 10.3390/ijms25115583 -
Plants (Basel, Switzerland) May 2024Plants and algae use light not only for driving photosynthesis but also to sense environmental cues and to adjust their circadian clocks via photoreceptors. Aureochromes...
Plants and algae use light not only for driving photosynthesis but also to sense environmental cues and to adjust their circadian clocks via photoreceptors. Aureochromes are blue-light-dependent photoreceptors that also function as transcription factors, possessing both a LOV and a bZIP domain. Aureochromes so far have only been detected in Stramenopile algae, which include the diatoms. Four paralogues of aureochromes have been identified in the pennate model diatom : PtAureo1a, 1b, 1c, and 2. While it was shown recently that diatoms have a diel rhythm, the molecular mechanisms and components regulating it are still largely unknown. Diel gene expression analyses of wild-type , a PtAureo1a knockout strain, and the respective PtAureo1 complemented line revealed that all four aureochromes have a different diel regulation and that PtAureo1a has a strong co-regulatory influence on its own transcription, as well as on that of other genes encoding different blue-light photoreceptors (CPF1, 2 and 4), proteins involved in photoprotection (Lhcx1), and specific bHLH transcription factors (RITMO1). Some of these genes completely lost their circadian expression in the PtAureo1a KO mutant. Our results suggest a major involvement of aureochromes in the molecular clock of diatoms.
PubMed: 38891274
DOI: 10.3390/plants13111465 -
Structural basis for an early stage of the photosystem II repair cycle in Chlamydomonas reinhardtii.Nature Communications Jun 2024Photosystem II (PSII) catalyzes water oxidation and plastoquinone reduction by utilizing light energy. It is highly susceptible to photodamage under high-light...
Photosystem II (PSII) catalyzes water oxidation and plastoquinone reduction by utilizing light energy. It is highly susceptible to photodamage under high-light conditions and the damaged PSII needs to be restored through a process known as the PSII repair cycle. The detailed molecular mechanism underlying the PSII repair process remains mostly elusive. Here, we report biochemical and structural features of a PSII-repair intermediate complex, likely arrested at an early stage of the PSII repair process in the green alga Chlamydomonas reinhardtii. The complex contains three protein factors associated with a damaged PSII core, namely Thylakoid Enriched Factor 14 (TEF14), Photosystem II Repair Factor 1 (PRF1), and Photosystem II Repair Factor 2 (PRF2). TEF14, PRF1 and PRF2 may facilitate the release of the manganese-stabilizing protein PsbO, disassembly of peripheral light-harvesting complexes from PSII and blockage of the Q site, respectively. Moreover, an α-tocopherol quinone molecule is located adjacent to the heme group of cytochrome b, potentially fulfilling a photoprotective role by preventing the generation of reactive oxygen species.
Topics: Photosystem II Protein Complex; Chlamydomonas reinhardtii; Thylakoids; Light-Harvesting Protein Complexes; Plant Proteins; Cytochrome b Group; Oxidation-Reduction; Reactive Oxygen Species; Light
PubMed: 38890314
DOI: 10.1038/s41467-024-49532-2