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International Journal of Molecular... Jan 2022Light is essential for photosynthesis but light levels that exceed an organism's assimilation capacity can cause serious damage or even cell death. Plants and microalgae... (Review)
Review
Light is essential for photosynthesis but light levels that exceed an organism's assimilation capacity can cause serious damage or even cell death. Plants and microalgae have developed photoprotective mechanisms collectively referred to as non-photochemical quenching to minimize such potential damage. One such mechanism is energy-dependent quenching (qE), which dissipates excess light energy as heat. Over the last 30 years, much has been learned about the molecular mechanism of qE in green algae and plants. However, the steps between light perception and qE represented a gap in our knowledge until the recent identification of light-signaling pathways that function in these processes in the green alga In this review, we summarize the high light and UV-mediated signaling pathways for qE in . We discuss key questions remaining about the pathway from light perception to photoprotective gene expression in . We detail possible differences between green algae and plants in light-signaling mechanisms for qE and emphasize the importance of research on light-signaling mechanisms for qE in plants.
Topics: Chlamydomonas reinhardtii; Gene Expression Regulation, Plant; Light; Light Signal Transduction; Models, Biological; Photochemical Processes
PubMed: 35054872
DOI: 10.3390/ijms23020687 -
Molecules (Basel, Switzerland) Oct 2020Light is a paramount parameter driving photosynthesis. However, excessive irradiance leads to the formation of reactive oxygen species that cause cell damage and hamper... (Review)
Review
Light is a paramount parameter driving photosynthesis. However, excessive irradiance leads to the formation of reactive oxygen species that cause cell damage and hamper the growth of photosynthetic organisms. Xanthophylls are key pigments involved in the photoprotective response of plants and algae to excessive light. Of particular relevance is the operation of xanthophyll cycles (XC) leading to the formation of de-epoxidized molecules with energy dissipating capacities. Neoxanthin, found in plants and algae in two different isomeric forms, is involved in the light stress response at different levels. This xanthophyll is not directly involved in XCs and the molecular mechanisms behind its photoprotective activity are yet to be fully resolved. This review comprehensively addresses the photoprotective role of 9'--neoxanthin, the most abundant neoxanthin isomer, and one of the major xanthophyll components in plants' photosystems. The light-dependent accumulation of all--neoxanthin in photosynthetic cells was identified exclusively in algae of the order Bryopsidales (Chlorophyta), that lack a functional XC. A putative photoprotective model involving all--neoxanthin is discussed.
Topics: Chlorophyta; Light-Harvesting Protein Complexes; Photosynthesis; Xanthophylls
PubMed: 33050573
DOI: 10.3390/molecules25204617 -
Pharmaceutics May 2024Sunscreen products are essential for shielding the skin from ultraviolet (UV) radiation, a leading cause of skin cancer. While existing products serve this purpose,... (Review)
Review
Sunscreen products are essential for shielding the skin from ultraviolet (UV) radiation, a leading cause of skin cancer. While existing products serve this purpose, there is a growing need to enhance their efficacy while minimizing potential systemic absorption of UV filters and associated toxicological risks. Liposomal-based formulations have emerged as a promising approach to address these challenges and develop advanced photoprotective products. These vesicular systems offer versatility in carrying both hydrophilic and lipophilic UV filters, enabling the creation of broad-spectrum sunscreens. Moreover, their composition based on phospholipids, resembling that of the stratum corneum, facilitates adherence to the skin's surface layers, thereby improving photoprotective efficacy. The research discussed in this review underscores the significant advantages of liposomes in photoprotection, including their ability to limit the systemic absorption of UV filters, enhance formulation stability, and augment photoprotective effects. However, despite these benefits, there remains a notable gap between the potential of liposomal systems and their utilization in sunscreen development. Consequently, this review emphasizes the importance of leveraging liposomes and related vesicular systems as innovative tools for crafting novel and more efficient photoprotective formulations.
PubMed: 38794323
DOI: 10.3390/pharmaceutics16050661 -
Biomolecules Feb 2021Systemic photoprotection (i.e., administration of substances such as nicotinamide, carotenoids, and vitamin D) may be important to reduce photocarcinogenesis or to...
BACKGROUND
Systemic photoprotection (i.e., administration of substances such as nicotinamide, carotenoids, and vitamin D) may be important to reduce photocarcinogenesis or to support long-term protection against UV irradiation. Clinical trials showed that oral nicotinamide is effective in reducing the onset of new nonmelanoma skin cancers (NMSCs), while other oral photoprotectors failed to achieve the reduction of new melanoma or NMSC formation in humans. The aim of this study was to summarize the current state of knowledge of systemic photoprotection and to evaluate the knowledge and attitude of dermatologists regarding these treatments.
METHODS
The survey was conducted on a sample of dermatologists recruited according to a snowball sampling procedure. The questionnaire consisted of a first part asking for characteristics of the participant and a second part with 12 specific questions on their knowledge about systemic photoprotection, particularly their knowledge of astaxanthin, β-carotene, nicotinamide, and vitamin D3.
RESULTS
One hundred eight dermatologists answered the survey. Most of them (85.2%) stated that oral photoprotectors have a role in the prevention of skin cancer, and responses mainly mentioned nicotinamide. More than half of them (54.6%) had prescribed all the considered oral photoprotectors, but the majority of them had prescribed nicotinamide, mainly for 2 to 3 months during summer, almost invariably ( = 106) associated with topical photoprotectors. Most dermatologists (>80%) were aware of scientific publications demonstrating an effect of systemic photoprotectors on NMSC.
CONCLUSIONS
Most Italian dermatologists have positive views on oral photoprotection in skin cancer and are aware of the demonstrated potential of nicotinamide in the prevention of NMSCs.
Topics: Chemoprevention; Dermatologists; Dermatology; Female; Health Knowledge, Attitudes, Practice; Humans; Italy; Male; Multivariate Analysis; Skin Neoplasms; Surveys and Questionnaires; Ultraviolet Rays
PubMed: 33672113
DOI: 10.3390/biom11020332 -
Biophysical Reviews Aug 2022Variable fluorescence of chlorophyll (CF) of the photosynthetic apparatus is an ample source of valuable information on physiological condition of photosynthetic... (Review)
Review
Variable fluorescence of chlorophyll (CF) of the photosynthetic apparatus is an ample source of valuable information on physiological condition of photosynthetic organisms. Currently, the most widespread CF-based technique is represented by recording pulse-amplitude modulated (PAM) induction of CF by saturating light. The CF-based monitoring techniques are increasingly employed for characterization of performance and stress resilience of microalgae in microalgal biotechnology. Analysis of CF induction curves reveals the fate of light energy absorbed by photosynthetic apparatus, the proportions of the energy that have been utilized for photochemistry (culture growth), and heat dissipated by photoprotective mechanisms. Hence CF and its derived parameters are an accurate proxy of the metabolic activity of the photosynthetic cell and the engagement of photoprotective mechanisms. This information is a solid foundation for making decisions on the microalgal culture management during the lab-scale and industrial-scale cultivation. Applications of CF and PAM include the monitoring of stressor (high light, nutrient deprivation, extreme temperatures, etc.) effects for assessment of the culture robustness. It also serves as a non-invasive express test for gauging the effect of assorted toxicants in microalgae. This approach is becoming widespread in ecological toxicology and environmental biotechnology, particularly for bioprospecting strains capable of the destruction of dangerous pollutants such as pharmaceuticals. In the review, we discuss the advantages and drawbacks of using CF-based methods for assessment of the culture conditions. Special attention is paid to the potential caveats and applicability of different variations of CF and PAM measurements for solving problems of microalgal biotechnology.
PubMed: 36124274
DOI: 10.1007/s12551-022-00951-9 -
International Journal of Molecular... Aug 2023Ultraviolet radiation (UVR) tends to damage key cellular machinery. Cells may adapt by developing several defence mechanisms as a response to such damage; otherwise,... (Review)
Review
Ultraviolet radiation (UVR) tends to damage key cellular machinery. Cells may adapt by developing several defence mechanisms as a response to such damage; otherwise, their destiny is cell death. Since cyanobacteria are primary biotic components and also important biomass producers, any drastic effects caused by UVR may imbalance the entire ecosystem. Cyanobacteria are exposed to UVR in their natural habitats. This exposure can cause oxidative stress which affects cellular morphology and vital processes such as cell growth and differentiation, pigmentation, photosynthesis, nitrogen metabolism, and enzyme activity, as well as alterations in the native structure of biomolecules such as proteins and DNA. The high resilience and several mitigation strategies adopted by a cyanobacterial community in the face of UV stress are attributed to the activation of several photo/dark repair mechanisms, avoidance, scavenging, screening, antioxidant systems, and the biosynthesis of UV photoprotectants, such as mycosporine-like amino acids (MAAs), scytonemin (Scy), carotenoids, and polyamines. This knowledge can be used to develop new strategies for protecting other organisms from the harmful effects of UVR. The review critically reports the latest updates on various resilience and defence mechanisms employed by cyanobacteria to withstand UV-stressed environments. In addition, recent developments in the field of the molecular biology of UV-absorbing compounds such as mycosporine-like amino acids and scytonemin and the possible role of programmed cell death, signal perception, and transduction under UVR stress are discussed.
Topics: Ultraviolet Rays; Ecosystem; Amino Acids; Cyanobacteria
PubMed: 37569755
DOI: 10.3390/ijms241512381 -
Antioxidants (Basel, Switzerland) Jul 2019Due to their potential health-promoting effects, carotenoids have drawn both scientific and public attention in recent years. The primary source of carotenoids in the... (Review)
Review
Due to their potential health-promoting effects, carotenoids have drawn both scientific and public attention in recent years. The primary source of carotenoids in the human skin is diet, mainly fruits, vegetables, and marine product, but they may originate from supplementation and topical application, too. In the skin, they accumulate mostly in the epidermis and act as a protective barrier to various environmental influences. Namely, the skin is exposed to numerous environmental factors, including ultraviolet radiation (UVR), air pollution, and smoking, that cause oxidative stress within the skin with consequent premature (extrinsic) aging. UVR, as the most prominent environmental factor, may cause additional detrimental skin effects, such as sunburn, DNA damage, and skin cancer. Therefore, photoprotection is the first line intervention in the prevention of premature aging and skin cancer. Numerous studies have demonstrated that carotenoids, particularly β-carotene, lycopene, lutein, and astaxanthin, have photoprotective effects, not only through direct light-absorbing properties, but also through their antioxidant effects (scavenging reactive oxygen species), as well as by regulation of UV light-induced gene expression, modulation of stress-dependent signaling, and/or suppression of cellular and tissue responses like inflammation. Interventional studies in humans with carotenoid-rich diet have shown its photoprotective effects on the skin (mostly by decreasing the sensitivity to UVR-induced erythema) and its beneficial effects in prevention and improvement of skin aging (improved skin elasticity and hydration, skin texture, wrinkles, and age spots). Furthermore, carotenoids may be helpful in the prevention and treatment of some photodermatoses, including erythropoietic protoporphyria (EPP), porphyria cutanea tarda (PCT) and polymorphous light eruption (PMLE). Although UVR is recognized as the main etiopathogenetic factor in the development of non-melanoma skin cancer (NMSC) and melanoma, and the photoprotective effects of carotenoids are certain, available studies still could not undoubtedly confirm the protective role of carotenoids in skin photocarcinogenesis.
PubMed: 31370257
DOI: 10.3390/antiox8080259 -
Indian Journal of Dermatology 2022
PubMed: 35656254
DOI: 10.4103/ijd.ijd_219_21 -
Plants (Basel, Switzerland) May 2023The ability of plants to respond to environmental fluctuations is supported by acclimatory adjustments in plant form and function that may require several days and... (Review)
Review
The ability of plants to respond to environmental fluctuations is supported by acclimatory adjustments in plant form and function that may require several days and development of a new leaf. We review adjustments in photosynthetic, photoprotective, and foliar vascular capacity in response to variation in light and temperature in terrestrial plants. The requirement for extensive acclimation to these environmental conditions in terrestrial plants is contrasted with an apparent lesser need for acclimation to different light environments, including rapid light fluctuations, in floating aquatic plants for the duckweed . Relevant features of include unusually high growth rates and photosynthetic capacities coupled with the ability to produce high levels of photoprotective xanthophylls across a wide range of growth light environments without compromising photosynthetic efficiency. These features also allow to maximize productivity and avoid problems during an abrupt experimental transfer of low-light-grown plants to high light. The contrasting responses of land plants and floating aquatic plants to the light environment further emphasize the need of land plants to, e.g., experience light fluctuations in their growth environment before they induce acclimatory adjustments that allow them to take full advantage of natural settings with such fluctuations.
PubMed: 37653846
DOI: 10.3390/plants12101928 -
Pediatric Rheumatology Online Journal Oct 2023Systemic lupus erythematosus (SLE) is a systemic autoimmune disease that is associated with multiple organ involvement and leads to significant morbidity and mortality....
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.
Topics: Humans; Female; Child; Adolescent; Male; Sunscreening Agents; Prospective Studies; Sunburn; Lupus Erythematosus, Systemic; Water
PubMed: 37848991
DOI: 10.1186/s12969-023-00901-z