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1.
Proc Natl Acad Sci U S A ; 121(42): e2411620121, 2024 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-39378097

RESUMEN

Zeaxanthin (Zea) is a key component in the energy-dependent, rapidly reversible, nonphotochemical quenching process (qE) that regulates photosynthetic light harvesting. Previous transient absorption (TA) studies suggested that Zea can participate in direct quenching via chlorophyll (Chl) to Zea energy transfer. However, the contamination of intrinsic exciton-exciton annihilation (EEA) makes the assignment of TA signal ambiguous. In this study, we present EEA-free TA data using Nicotiana benthamiana thylakoid membranes, including the wild type and three NPQ mutants (npq1, npq4, and lut2) generated by CRISPR/Cas9 mutagenesis. The results show a strong correlation between excitation energy transfer from excited Chl Qy to Zea S1 and the xanthophyll cycle during qE activation. Notably, a Lut S1 signal is absent in the npq1 thylakoids which lack zeaxanthin. Additionally, the fifth-order response analysis shows a reduction in the exciton diffusion length (LD) from 62 ± 6 nm to 43 ± 3 nm under high light illumination, consistent with the reduced range of exciton motion being a key aspect of plants' response to excess light.


Asunto(s)
Clorofila , Transferencia de Energía , Nicotiana , Fotosíntesis , Tilacoides , Zeaxantinas , Zeaxantinas/metabolismo , Clorofila/metabolismo , Nicotiana/metabolismo , Tilacoides/metabolismo , Xantófilas/metabolismo , Mutación
2.
Plant Physiol ; 2024 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-39365917

RESUMEN

Stress exerted by excess captured light energy in cyanobacteria is prevented by the photoprotective activity of the orange carotenoid protein (OCP). Under high light, the OCP converts from an orange, inactive form (OCPO) into the red form (OCPR) that binds to and quenches the phycobilisome (PBS). Structurally, the OCP consists of two domains: the N-terminal effector domain and a C-terminal regulatory domain. Structural analysis of the OCP-PBS complex showed that the N-terminal domains of an OCP dimer interact with the PBS core. These N-terminal OCP domains have single domain protein paralogs known as Helical Carotenoid Proteins (HCPs). Using phycobilisome quenching assays, we show that the HCP4 and HCP5 homologs efficiently quench PBS fluorescence in vitro, surpassing the quenching ability of the OCP. This is consistent with computational quantum mechanics/molecular mechanics results. Interestingly, when using a maximum quenching concentration of OCP with phycobilisomes, HCP5 addition further increases phycobilisome quenching. Our results provide mechanistic insight into the quenching capacity and roles of HCP4 and HCP5 in cyanobacteria, suggesting that they are more than simply functionally redundant to the OCP.

3.
aBIOTECH ; 5(3): 381-393, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39279858

RESUMEN

Plants absorb light energy for photosynthesis via photosystem complexes in their chloroplasts. However, excess light can damage the photosystems and decrease photosynthetic output, thereby inhibiting plant growth and development. Plants have developed a series of light acclimation strategies that allow them to withstand high light. In the first line of defense against excess light, leaves and chloroplasts move away from the light and the plant accumulates compounds that filter and reflect the light. In the second line of defense, known as photoprotection, plants dissipate excess light energy through non-photochemical quenching, cyclic electron transport, photorespiration, and scavenging of excess reactive oxygen species. In the third line of defense, which occurs after photodamage, plants initiate a cycle of photosystem (mainly photosystem II) repair. In addition to being the site of photosynthesis, chloroplasts sense stress, especially light stress, and transduce the stress signal to the nucleus, where it modulates the expression of genes involved in the stress response. In this review, we discuss current progress in our understanding of the strategies and mechanisms employed by plants to withstand high light at the whole-plant, cellular, physiological, and molecular levels across the three lines of defense.

5.
Bioorg Chem ; 153: 107756, 2024 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-39243737

RESUMEN

Investigation into the interactions between photoprotective agents and skin can offer a precise understanding of their biological behaviors in vitro and in vivo, providing crucial insights for generating new substances. For this purpose, we designed and synthesized a series of naphthoxazine derivatives and examined their photoprotective properties. 1,3-naphthoxazine derivatives were synthesized through the multi-component reaction of 2-naphthol, arylamines and aromatic aldehydes in the presence of copper(II) trifluoromethanesulfonate (Cu(OTf)2) and (±)-Camphor-10-sulfonic acid ((±)-CSA) catalyst system under sonication. The potential of these synthesized 1,3-naphthoxazine derivatives as antioxidants and viable organic structural-based sunscreen ingredients has been investigated. Sun protection factor (SPF) assay results showed that especially compounds 4i, 4c, 4k, 4d, 4r, and 4h had remarkably high activity (23.65, 23.57, 23.04, 21.94, 20.80, and 20.26, respectively at 900 µg/mL concentration). Additionally, antioxidant activity of the synthesized compounds was evaluated and compounds 4h, 4e, 4b, and 4j exhibited the highest activities in DPPH scavenging activity assay (86.46 %, 82.83 %, 80.78 %, and 80.65 % respectively at 400 µg/mL concentration). The synthesized compounds exhibit promising characteristics for effective UV radiation absorption, suggesting their suitability for inclusion in sunscreen formulations. Cytotoxic activity of compound 4k against normal human fibroblast cell line (MRC-5) was determined by CVDK-8 method. The results revealed that the compound provided remarkable viability (87.55 %) of MRC-5 cells at concentration of 100 µM. The study explores their efficacy in providing broad-spectrum protection against UVA and UVB rays, degradation and photostability, ADMET profile, and other pharmacokinetic properties.

6.
Rice (N Y) ; 17(1): 62, 2024 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-39285086

RESUMEN

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

7.
AAPS PharmSciTech ; 25(7): 212, 2024 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-39242428

RESUMEN

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


Asunto(s)
Nanopartículas , Nanotecnología , Protectores Solares , Rayos Ultravioleta , Animales , Humanos , Antioxidantes/administración & dosificación , Antioxidantes/química , Antioxidantes/farmacología , Portadores de Fármacos/química , Lípidos/química , Nanopartículas/química , Nanotecnología/métodos , Polímeros/química , Piel/metabolismo , Piel/efectos de los fármacos , Absorción Cutánea/efectos de los fármacos , Factor de Protección Solar , Protectores Solares/química , Protectores Solares/administración & dosificación , Rayos Ultravioleta/efectos adversos
8.
Food Chem X ; 23: 101648, 2024 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-39113732

RESUMEN

Retinal disease has become the major cause of visual impairment and vision loss worldwide. Carotenoids, which have the potential antioxidant and eye-care activities, have been widely used in functional foods. Our previous study showed that fucoxanthin could exert photoprotective activity in UVB-induced retinal müller cells (RMCs). To extend the application of fucoxanthin in food industry, fucoxanthin, Undaria pinnatifida pulp (UPP), carrageenan, and other ingredients were mixed to prepare seaweed-flavoured photoprotective gummies in this study. The structural and functional properties of the gummies were then evaluated by physicochemical test and cell experiments. As a result, fucoxanthin enriched gummies presented favourable structural properties and flavour. The hydroxyl groups in fucoxanthin and κ-carrageenan are bonded through hydrogen bonds, forming the spatial network structure inside the gummies, enhancing its elasticity. The gummies showed significant antioxidant effect and alleviated the UVB oxidation damage in RMCs. Moreover, the main ingredients carrageenan and UPP improved the stability of fucoxanthin during in vitro digestion. The results enhance the application of fucoxanthin in functional food with photoprotective activity.

10.
Artículo en Inglés | MEDLINE | ID: mdl-39108105

RESUMEN

Antioxidants play a pivotal role in maintaining skin health and integrity, combating the deleterious effects of oxidative stress induced by environmental aggressors such as UV ra-diation, pollution, and lifestyle factors. This paper reviews the contributions of key antioxidants, including Vitamin C, Vitamin E, Vitamin A, green tea extract, Coenzyme Q10, Resveratrol, Selenium, and Polyphenols, in skin health care. Vitamin C, known for its collagen synthesis promotion and photoprotection properties, alongside Vitamin E, a lipid-soluble antioxidant, syn-ergistically works to neutralize free radicals and repair damaged skin cells. Vitamin A, in the form of retinol, plays a critical role in skin cell regeneration and the maintenance of skin integ-rity. Green tea extract, rich in Polyphenols, offers anti-inflammatory and anticarcinogenic prop-erties, making it a potent ingredient for skin protection. Coenzyme Q10, a naturally occurring antioxidant in the body, aids in energy production for cell repair and regeneration, while Resveratrol, found in grapes and berries, provides anti-ageing benefits by enhancing skin's re-sistance to oxidative stress. Selenium, an essential mineral, contributes to the protection of skin cells from oxidative damage. The incorporation of these antioxidants in skincare products and dietary sources is discussed, highlighting the importance of a holistic approach in skincare re-gimes. The paper emphasizes the synergy between topical applications and dietary intake of antioxidants, advocating for a comprehensive strategy for promoting skin health and preventing age-related skin alterations. Method: For the review article, a variety of search engines and databases were used to identify relevant articles. Furthermore, for biomedical literature focusing on antioxidants and their ef-fects on skin health, PubMed was used. Moreover, to access a wide range of scholarly articles, including those related to dermatology and skincare, Google Scholar was used. Scopus provides comprehensive coverage of peer-reviewed literature across various scientific disciplines. Web of Science identifies high-impact articles and research on antioxidants in skincare. In addition, for accessing full-text articles on antioxidants and their applications in dermatology, Science Direct was used. The inclusion criteria for the review paper were as follows: only studies pub-lished in peer-reviewed journals were included to ensure the credibility and reliability of the information. Articles published in English were considered, to avoid language-related biases and ensure comprehension. Studies published within the last 10 years were included to provide the most current insights into antioxidant research in skincare. Articles must specifically focus on the role of antioxidants (Vitamin C, Vitamin E, Vitamin A, green tea extract, Coenzyme Q10, Resveratrol, Selenium, Polyphenols) in skin health care. Both experimental studies (in vivo and in vitro) and clinical trials were included to provide a comprehensive overview of the antioxidant effects. Full-text articles were included to allow for thorough data extraction and analysis. The exclusion criteria for the review paper were as follows: Publications that were not peer-re-viewed, such as editorials, opinion pieces, and non-scholarly articles, were excluded. Articles published in languages other than English were excluded due to potential translation challenges and to maintain consistency. Studies that did not focus on the specified antioxidants or their impact on skin health were excluded. Duplicate publications were excluded to avoid redundancy in the review. Articles with insufficient or incomplete data were excluded to ensure the quality and reliability of the review findings.

13.
Plant Cell Environ ; 2024 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-39148214

RESUMEN

Chilling stress is a major environmental factor that significantly reduces crop production. To adapt to chilling stress, plants activate a series of cellular responses and accumulate an array of metabolites, particularly proline. Here, we report that the transcription factor SlWRKY51 increases proline contents in tomato (Solanum lycopersicum) under chilling stress. SlWRKY51 expression is induced under chilling stress. Knockdown or knockout of SlWRKY51 led to chilling-sensitive phenotypes, with lower photosynthetic capacity and more reactive oxygen species (ROS) accumulation than the wild type (WT). The proline contents were significantly reduced in SlWRKY51 knockdown and knockout lines under chilling stress, perhaps explaining the phenotypes of these lines. D-1-pyrroline-5-carboxylate synthetase (P5CS), which catalyses the rate-limiting step of proline biosynthesis, is encoded by two closely related P5CS genes (P5CS1 and P5CS2). We demonstrate that SlWRKY51 directly activates the expression of P5CS1 under chilling stress. In addition, the VQ (a class of plant-specific proteins containing the conserved motif FxxhVQxhTG) family member SlVQ10 physically interacts with SlWRKY51 to enhance its activation of P5CS1. Our study reveals that the chilling-induced transcription factor SlWRKY51 enhances chilling tolerance in tomato by promoting proline accumulation.

14.
Photodermatol Photoimmunol Photomed ; 40(5): e12996, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39149878

RESUMEN

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


Asunto(s)
Dermatólogos , Melanosis , Pigmentación de la Piel , Protectores Solares , Protectores Solares/administración & dosificación , Humanos , España , Femenino , Encuestas y Cuestionarios , Masculino , Internado y Residencia , Adulto , Pautas de la Práctica en Medicina/estadística & datos numéricos , Persona de Mediana Edad
15.
Plants (Basel) ; 13(13)2024 Jun 24.
Artículo en Inglés | MEDLINE | ID: mdl-38999586

RESUMEN

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.

16.
J Mol Model ; 30(8): 255, 2024 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-38970658

RESUMEN

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


Asunto(s)
Antioxidantes , Diseño Asistido por Computadora , Diseño de Fármacos , Resveratrol , Protectores Solares , Rayos Ultravioleta , Protectores Solares/química , Antioxidantes/química , Antioxidantes/farmacología , Resveratrol/química , Propiofenonas/química , Teoría Funcional de la Densidad , Estilbenos/química , Estilbenos/farmacología , Modelos Moleculares , Teoría Cuántica , Estructura Molecular
17.
J Phycol ; 60(4): 942-955, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39016211

RESUMEN

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


Asunto(s)
Carotenoides , Luz , Fotosíntesis , Rhodophyta , Rhodophyta/fisiología , Rhodophyta/metabolismo , Carotenoides/metabolismo , Xantófilas/metabolismo , Estrés Fisiológico
18.
J Am Acad Dermatol ; 2024 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-39025264

RESUMEN

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

19.
Biochim Biophys Acta Bioenerg ; 1865(4): 149500, 2024 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-39074571

RESUMEN

In high light, the antenna system in oxygenic photosynthetic organisms switches to a photoprotective mode, dissipating excess energy in a process called non-photochemical quenching (NPQ). Diatoms exhibit very efficient NPQ, accompanied by a xanthophyll cycle in which diadinoxanthin is de-epoxidized into diatoxanthin. Diatoms accumulate pigments from this cycle in high light, and exhibit faster and more pronounced NPQ. The mechanisms underlying NPQ in diatoms remain unclear, but it can be mimicked by aggregation of their isolated light-harvesting complexes, FCP (fucoxanthin chlorophyll-a/c protein). We assess this model system by resonance Raman measurements of two peripheral FCPs, trimeric FCPa and nonameric FCPb, isolated from high- and low-light-adapted cells (LL,HL). Quenching is associated with a reorganisation of these proteins, affecting the conformation of their bound carotenoids, and in a manner which is highly dependent on the protein considered. FCPa from LL diatoms exhibits significant changes in diadinoxanthin structure, together with a smaller conformational change of at least one fucoxanthin. For these LL-FCPa, quenching is associated with consecutive events, displaying distinct spectral signatures, and its amplitude correlates with the planarity of the diadinoxanthin structure. HL-FCPa aggregation is associated with a change in planarity of a 515-nm-absorbing fucoxanthin, and, to a lesser extent, of diadinoxanthin. Finally, in FCPb, a blue-absorbing fucoxanthin is primarily affected. FCPs thus possess a plastic structure, undergoing several conformational changes upon aggregation, dependent upon their precise composition and structure. NPQ in diatoms may therefore arise from a combination of structural changes, dependent on the environment the cells are adapted to.


Asunto(s)
Diatomeas , Complejos de Proteína Captadores de Luz , Xantófilas , Diatomeas/metabolismo , Diatomeas/química , Complejos de Proteína Captadores de Luz/metabolismo , Complejos de Proteína Captadores de Luz/química , Xantófilas/química , Xantófilas/metabolismo , Espectrometría Raman , Clorofila/metabolismo , Clorofila/química , Luz
20.
New Phytol ; 244(1): 65-73, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39061101

RESUMEN

The plant cuticle is located at the interface of the plant with the environment, thus acting as a protective barrier against biotic and abiotic external stress factors, and regulating water loss. Additionally, it modulates mechanical stresses derived from internal tissues and also from the environment. Recent advances in the understanding of the hydric, mechanical, thermal, and, to a lower extent, optical and electric properties of the cuticle, as well as their phenomenological connections and relationships are reviewed. An equilibrium based on the interaction among the different biophysical properties is essential to ensure plant growth and development. The notable variability reported in cuticle geometry, surface topography, and microchemistry affects the analysis of some biophysical properties of the cuticle. This review aimed to provide an updated view of the plant cuticle, understood as a modification of the cell wall, in order to establish the state-of-the-art biophysics of the plant cuticle, and to serve as an inspiration for future research in the field.


Asunto(s)
Fenómenos Biofísicos , Pared Celular/fisiología , Pared Celular/ultraestructura , Biofisica , Epidermis de la Planta/fisiología , Plantas/anatomía & histología , Plantas/metabolismo
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