Search Results (276)

One of the first organisms to appear on Earth was cyanobacteria, which carried out oxygenic photosynthesis. The oxygen they produced contributed to the ozone layer’s formation. However, before this happened, cyanobacteria had to cope with various forms of radiation, including ultraviolet radiation (UVR), that reached the surface of young Earth. Billions of years ago, before the Earth’s ozone layer formed, the planet was constantly exposed to intense UVR. This radiation, especially UVB and UVC, was strong enough to break down proteins and nucleic acids. Cyanobacteria have a variety of defence mechanisms that allow them to thrive under adverse conditions. These mechanisms include the avoidance of UVR through migration or mat formation, DNA repair, antioxidant enzyme activity, and biosynthesis of UVR-absorbing compounds. Although most of today’s dangerous UVR is absorbed by the ozone layer, future space exploration has led to a closer examination of the effects of UVR, especially UVC, on various organisms, including cyanobacteria. The flexibility of cyanobacteria to tolerate unfavourable conditions makes them potential candidates for future space exploration. This brief overview provides some information on the effects of UVR on cyanobacteria, the defence mechanisms of cyanobacteria against UVR, and the potential use of cyanobacteria in life-support systems in space missions. Full article

The trade-off between reducing pesticide use and ensuring effective crop protection is a key challenge for sustainable agriculture. Stimulating the plant’s natural defense mechanisms represents a promising alternative. In this study, we evaluated the potential of pulsed light as a physical elicitor in tomato (Solanum lycopersicum). This technology is based on the emission of brief but intense light flashes, covering a broad spectrum (from UV-C to infrared), capable of simultaneous activation of multiple signaling pathways. Tomato plants were treated using a standard protocol and subjected to biochemical, transcriptional, physiological, and pathological analyses. The treatment significantly increased the activity of defense-related and antioxidant enzymes, the accumulation of phenolic compounds and callose, and the expression of key immunity-related genes. Upon Botrytis cinerea inoculation, pretreated tomato plants showed enhanced defense responses and a significant reduction in disease severity, indicating a priming effect. The standard protocol did not impair photosynthesis, growth, or yield. These findings highlight pulsed light as an innovative technology for integrated crop protection. Full article

Mycosporine-like amino acids (MAAs) are secondary metabolites of interest for the development of natural sunscreens, owing to their antioxidant activity and ultraviolet radiation (UVR)-absorbing properties. MAA-rich aqueous extracts obtained from the Chilean red alga Mazzaella laminarioides (locally known as luga cuchara) were analyzed by HPLC and loaded into chitosan nanoparticles (CSNPs), with an encapsulation efficiency of 90.1%. The resulting CS nanoformulations (CSNFs) were characterized by FTIR spectroscopy, DLS and TEM microscopy, confirming the presence of nanoparticles with a core diameter of 94 ± 11 nm and FTIR absorption bands accounting for CS functional groups. Pre-treatment of HaCaT keratinocytes with CSNFs conferred complete protection against low-to-moderate UVA doses (5, 10, 15, and 30 J/cm²). Remarkably, cells still retained a protection efficacy of 64.7% under lethal UVA exposure (60 J/cm²), with gene expression evidence suggesting the activation of a compensatory stress response to photo-oxidative damage. CSNFs were also capable of restoring cell viability in post-treatment experiments at UVA doses of 30 J/cm² (100% cell viability) and 60 J/cm² (~43% cell viability). This is the first demonstration that nanoencapsulation of an MAA-rich algal extract yields superior UVA photoprotection in human keratinocytes compared with non-encapsulated MAA-based formulations, contributing to the effort of developing eco-friendly sunscreens. Full article

Ultraviolet radiation (UVR) is a well-established risk factor for ocular diseases; however, the ultraviolet-blocking properties of daily disposable contact lenses remain insufficiently characterized. This study evaluated thirteen commercially available lenses to determine their spectral transmittance across UV-B, UV-A, and visible light ranges using a UV–visible spectrophotometer. The oxygen permeability, central thickness, water content, and FDA material classification of each lens were documented, and oxygen transmissibility was subsequently calculated. A generalized linear mixed model (GLMM) was applied to identify predictors of spectral transmittance. All lenses demonstrated high visible light transmittance (>88%), but exhibited substantial variation in UV attenuation. While several lenses effectively blocked most UV radiation, others transmitted more than 70%. The analysis revealed that lens power was the most consistent predictor of spectral transmittance, with higher minus powers associated with reduced UV-blocking efficacy. Moisture content and material classification also influenced UV protection but had minimal effect on visible light transmission. In conclusion, daily disposable contact lenses vary considerably in their UV-blocking capabilities, and although lens power cannot be altered, consideration of material composition and UV transmittance properties may assist in selecting lenses that provide optimal ocular protection. Full article

Background: Folic acid (FA), also known as vitamin B9, functions as a co-factor in many cellular processes. Ultraviolet radiation (UV) has been shown to cause the formation of free radicals, and chronic exposure of the skin to UV radiation has been demonstrated to result in many adverse effects. Skin protection against harmful environmental factors is one of the aims of cosmetic products. One such substance is folic acid. However, aqueous FA solutions decompose after exposure to UV radiation, and the decomposition products can exhibit variable pro/anti-oxidative roles depending on the cell type and its environment. Objectives: The objective of the present study was to demonstrate the effectiveness of folic acid as a UV-protective agent in vitro cell culture model. Methods: The experimental model comprised an in vitro culture of normal human fibroblasts derived from adult skin (NHDF-Ad). Paramagnetic electron resonance (EPR) was used to assess the interaction of folic acid with free radicals after exposure to UV radiation. RT-qPCR was utilized to evaluate the impact of ultraviolet (UV) radiation on the expression of selected cell cycle regulatory genes (CCND1, P53, BAX, and BCL-2) in vitro cultured fibroblasts that were protected by folic acid. Results: EPR studies revealed the antioxidant properties of folic acid. Free radical forms of folic acid are induced during UV irradiation. The strong effect of UV irradiation on interactions of folic acid with free radicals was observed. The interaction was found to be weaker for the irradiated samples. Molecular studies have demonstrated a decline in the BAX/BCL-2 ratio in cells that have been treated with folic acid and exposed to UV radiation in comparison to the BAX/BCL-2 ratio observed in cells that have been exposed exclusively to UV radiation and not treated with folic acid. Conclusions: Whilst molecular and EPR studies both confirm the effectiveness of folic acid as a UV-protective ingredient in cosmetics and pharmaceutical products, further research in this area is required. Full article

Lignocellulosic biomass may play a major role in the production of biofuels, bioplastics, sugar, paper, and various other industrial products. In addition, it is a key trait in plants due to its contribution to lodging resistance. Fiber also shows a significant negative correlation with most yield traits and all sugar traits. As the most harvested crop globally by tonnage, sugarcane is an important resource for both sugar and bioenergy production. In this study, a panel of sugarcane clones was utilized to investigate the fiber content. This panel included 17 core parental lines derived from 11 countries involved in sugarcane cultivation and breeding. It represented the genetic base of commercial sugarcane breeding programs in China and other countries. The objective of this research was to identify molecular markers and candidate genes associated with fiber content in sugarcane using genome-wide association studies (GWASs). By integrating 5,964,084 high-quality single-nucleotide polymorphisms (SNPs) with phenotypic data collected across five different environments, a total of 69 SNPs spanning 41 quantitative trait loci (QTLs) were identified. Based on functional annotations and genomic positions, these QTLs contained 52 candidate genes. These candidate genes encoded the ultraviolet-B receptor (UVR8), leucine-rich repeat receptor-like kinases (LRR-RLKs), serine/threonine kinases (STKs), cellulose synthase (CESA), vegetative cell wall protein glycoproteins1 (gp1), F-box protein, MYB transcription factor, and so on. These genes could directly or indirectly influence the fiber content in sugarcane. Furthermore, according to previous studies, among these candidate genes, five located in four QTL regions were proposed to be the most critical. They included Sspon.02G0041160-2C, encoding CESA; Sspon.03G0039010-1C and Sspon.03G0039030-1C, both encoding gp1; Sspon.06G0023090-1B, encoding an F-box protein; and Sspon.07G0019440-2C, encoding a MYB transcription factor. The genetic basis of the fiber content was explored using elite breeding lines and their derivatives from the Chinese sugarcane breeding program. These candidate genes represent promising targets for future functional studies and may contribute to the development of different types of sugarcane varieties with correspondingly suitable fiber content through marker-assisted selection. Full article

Exposure to sunlight, whose main component is UV radiation (UVR), leads to various skin damage such as sunburns, premature aging, or more severe issues such as increased symptoms of autoimmune disease and skin cancer. Therefore, there is a growing interest in developing improved photoprotective agents that can protect skin from sunlight incidence and antioxidants that counteract the oxidative stress caused by it. Lichens are a source of such agents since they adapt to extreme environments including those with high UVR by biosynthesizing metabolites with those properties. In this study, brialmontin 2 (1), physciosporin (2), and pseudocyphellarin A (3) were isolated for the first time from the lichen Pseudocyphellaria berberina (G. Forst.) D. J. Galloway & P. James, along with calycin (4) and 22-hydroxystictan-3-one (5). Their structural characterization was carried out by spectroscopy (¹H and ¹³C NMR). Sun protection factor (SPF) along with critical wavelength (λ_crit), a UVA/UVB ratio (UVA/UVB-r) of one to five, and acetone extract (AE) were evaluated spectrophotometrically as a measure of their UVB and UVA photoprotective capacities, respectively. Additionally, their antioxidant activity was measured by scavenging DPPH free radicals (RSA). Compounds 2, 4, and AE showed “medium” UVB photoprotective capacities (with SPFs between 15 and 30). Additionally, 4 and AE presented “maximum” UVA photoprotective capacities (λ_crit > 370 nm and UVA/UVB-r > 0.8), whereas this activity was “good” for 2 and 3 (λ_crit 350 to 370 nm and UVA/UVB-r 0.4 to 0.6), and “moderate” for 1 (λ_crit 335 to 350 nm and UVA/UVB-r 0.2 to 0.4). All compounds and AE showed antioxidant activity, standing out were AE and 4 with activity comparable to the controls (ca. 95 and 81 RSA %, respectively, at 1000 ppm). AE and 4 are dual agents with photoprotective (UVB-UVA) and antioxidant capacities that could help prevent skin damage associated with sunlight. In silico assays suggest that 4 spontaneously diffuses into the stratum corneum with limited absorption through the skin. Additionally, 4 lacks potential toxicity to Normal Human Epidermal Keratinocytes (showing viability ca. 70% at 100 ppm); therefore, it is a candidate for the development of sunscreen formulations. Full article

Religious panel paintings (icons) play a pivotal role in the rituals of the Eastern Orthodox Christian Church. However, their continuous use often results in physical degradation, prompting remedial interventions. Quite commonly, alterations were treated by simply applying new paint layers directly over the decayed original, while in some cases, old icons were overpainted merely as a means to renovate and modernize them. Therefore, numerous overpainted icons are currently housed in churches, museums, and private collections across Greece. This study focuses on the investigation of a post-Byzantine icon of Christ Pantokrator, which displays extensive overpainting while retaining a few visible fragments of the original composition. The objective was to assess the extent and condition of preservation of the original artwork, to identify materials and techniques used both in the initial painting and in subsequent restoration phases, and to distinguish between those phases. To achieve these aims, a fully non-invasive diagnostic methodology was implemented, including visible light photography, ultraviolet radiation imaging (UVR/UVL), hyperspectral imaging (MuSIS HS), infrared reflectography (IRRef), X-ray radiography, and macroscopic X-ray fluorescence scanning (MA-XRF). The findings confirm that the original painting remains substantially preserved and is of high artistic quality. Moreover, analysis revealed at least two distinct phases of overpainting, likely dating from the 20th century, while the results suggest that the original artwork probably dates to the first half of the 18th century. The study highlights the need to use complementary techniques in order to non-invasively assess complex artifacts like overpainted icons and offers valuable insights into historical restoration practices providing foundation for future conservation planning. Full article

The development of a new salt–alkaline-tolerant hybrid japonica rice is crucial for enhancing japonica rice supply and ensuring national food security. Utilizing molecular marker-assisted selection (MAS) technology combining Kompetitive Allele-Specific PCR (KASP) markers and a gene breeding chip, the salt-tolerant gene SKC1 was introgressed into a rice genotype Fan 14. This led to the development of Shenyanhui 1, a new high-quality, strongly heterotic, and salt-tolerant japonica restorer line. Subsequently, the high-quality, salt-tolerant japonica three-line hybrid rice variety Shenyanyou 1 was developed by crossing the BT-type japonica cytoplasmic male sterile (CMS) line Shen 21A with the restorer line Shenyanhui 1. Shenyanyou 1 carries the major salt tolerance gene SKC1, exhibiting excellent salt tolerance with seedling stage salt tolerance reaching level 5. Under precise salt tolerance evaluation throughout its growth cycle, Shenyanyou 1 achieved a yield of 3640.5 kg/hm², representing an extremely significant increase of 20.7% over the control variety Yandao 21. Shenyanyou 1 exhibits superior grain quality, meeting the Grade 3 high-quality rice standards issued by the Ministry of Agriculture. Shenyanyou 1 has good comprehensive resistance, aggregating rice blast resistance genes such as Pi2, Pita, Pizt and LHCB5, bacterial blight resistance genes Xa26/Xa3, stripe blast resistance gene STV11, semi-dwarf gene Sdt97, nitrogen-efficient utilization gene NRT1.1B, the light repair activity enhancement gene qUVR-10, the cold resistance gene qLTG3-1, and the iron tolerance gene OsFRO1. It has good resistance to biotic and abiotic stresses. This paper details the breeding process, key agronomic traits, salt tolerance, yield performance, and grain quality characteristics of Shenyanyou 1. Full article

Investigating the microbial community structure and stress-tolerance mechanisms in the rhizospheres of salt-adapted plants along saline lakes is critical for understanding plant–microbe interactions in extreme environments and developing effective strategies for saline–alkaline soil remediation. This study explored the rhizosphere microbiomes of four salt-adapted species (Suaeda glauca, Artemisia carvifolia, Chloris virgata, and Limonium bicolor) from the Yuncheng Salt Lake region in China using high-throughput sequencing. Cultivable salt-tolerant plant growth-promoting rhizobacteria (PGPR) were isolated and characterized to identify functional genes related to stress resistance. Results revealed that plant identity and soil physicochemical properties jointly shaped the microbial community composition, with total organic carbon being a dominant driver explaining 17.6% of the variation. Cyanobacteria dominated low-salinity environments, while Firmicutes thrived in high-salinity niches. Isolated PGPR strains exhibited tolerance up to 15% salinity and harbored genes associated with heat (htpX), osmotic stress (otsA), oxidative stress (katE), and UV radiation (uvrA). Notably, Peribacillus and Isoptericola strains demonstrated broad functional versatility and robust halotolerance. Our findings highlight that TOC (total organic carbon) plays a pivotal role in microbial assembly under extreme salinity, surpassing host genetic influences. The identified PGPR strains, with their stress-resistance traits and functional gene repertoires, hold significant promise for biotechnological applications in saline–alkaline soil remediation and sustainable agriculture. Full article

Ultraviolet radiation (UVR) is a major contributor to skin aging and carcinogenesis, primarily through the induction of DNA damage. While conventional sunscreens provide passive protection by blocking UVR, active photoprotection using DNA repair enzymes offers a strategy to reverse UV-induced DNA lesions at the molecular level. Enzymes such as photolyase, T4 endonuclease V, and 8-oxoguanine glycosylase address distinct types of DNA damage through light-dependent and -independent mechanisms, complementing the skin’s endogenous repair systems. Advances in nanocarrier technologies and encapsulation methods have improved the stability and delivery of these enzymes in topical formulations. Emerging evidence from clinical studies indicates their potential in reducing actinic keratoses, pigmentation disorders, and photoaging signs, although challenges in regulatory approval, long-term efficacy validation, and formulation optimization remain. This review provides a comprehensive synthesis of the mechanistic, clinical, and formulation aspects of enzyme-based photoprotection, outlines regulatory and ethical considerations, and highlights future directions, including CRISPR-based repair and personalized photoprotection strategies, establishing enzyme-assisted sunscreens as a next-generation approach to comprehensive skin care. Full article

Ultraviolet radiation (UVR) represents significant risks to both textile durability and human health. Natural dyes are gaining attention as eco-friendly alternatives to synthetic UV-blocking agents, offering aesthetic and functional benefits. This study explores the UV-protective properties of 100% cotton knit fabrics dyed with natural dyes—indigo, weld, and madder—using different mordanting processes, including materials with mordant abilities such as alum, pomegranate peel, and tannin extracted from quebracho. Twenty samples were evaluated, including undyed, individually treated, and combined dye-mordant formulations. UV protection was assessed through spectral transmittance and Ultraviolet Protection Factor (UPF) measurements before and after washing. The results showed that natural dyes significantly improved the UV resistance of cotton fabrics, particularly when combined with products like pomegranate and the tannin–alum mixture. Notably, some samples demonstrated improved UPF and became darker after washing, such as mordant combinations like tannin with alum. These findings suggest that natural dye, when combined with appropriate mordants, offers a sustainable and effective approach to producing UV-protective textiles. This is particularly valuable in children’s clothing, where chemical safety and sun protection are crucial. Future research should investigate the influence of pH on dye stability and UV-blocking performance to optimise formulations for industrial use and long-term functionality. Full article

Background: In addition to the well-known vitamin D metabolites 25(OH)D and 1,25(OH)₂D, the catabolite 24,25(OH)₂D may also reflect vitamin D status and influence biological and skeletal processes. However, the effects of UVR-induced synthesis on 24,25(OH)₂D levels and the 25-VMR (24,25(OH)₂D3:25(OH)D3 ratio) remain unclear. Objectives: We aimed to assess how a single standardised UVR dose influences the production of 25(OH)D3, 24,25(OH)₂D3, 1,25(OH)₂D3 and 25-VMR, with a comparison between younger and older adults being conducted to explore potential age-related differences in vitamin D metabolism. Methods: A total of 11 young (18–40 years; 7M, 4F) and 10 older (65–89 years; 6M, 4F) skin type I-III volunteers received a single sub-erythemal dose of solar simulated UVR (SSR) (95% UVA: 320–400 nm, 5% UVB: 290–320 nm, 1.3 standard erythemal dose) during winter time in the UK (vitamin D trough season), exposing approximately 35% of the body surface area. The Blood was assayed for 25(OH)D3, 24,25(OH)₂D3 and 1,25(OH)₂D3 using LC-MS/MS at baseline, 24 h and 7 days following UVR exposure. Results: There was a significant increase in 25(OH)D3 from baseline (44 ± 22 nmoL/L) to 24 h post-UVR (48 ± 22 nmoL/L) in the combined age group (p = 0.044), but no significant differences were found in 24,25(OH)₂D3 in the combined group, or between young and older volunteers for both metabolites. 1,25(OH)₂D3 concentrations were higher in young groups (163 ± 60 pmoL/L) than in older (105 ± 38 pmoL/L) groups at 7 days post-UVR (p = 0.044). The 25-VMR decreased from baseline (9 ± 3) to 24 h post-UVR (7.5 ± 2.1) in the combined group (p = 0.003). Conclusions: Our data suggest that a single sub-erythemal UVR challenge does not influence 24,25(OH)₂D3 concentration in younger and older adults at 24 h and 7 days post-UVR and that the significant difference seen in the 25-VMR between baseline and 24 h post-UVR is due to the increase in 25(OH)D3 concentration post-UVR. This is in line with vitamin D oral supplementation studies, and indicates that low doses of UVR trigger the metabolic pathway, without affecting the catabolic pathway. Full article

The incidence of skin carcinoma has significantly increased among the Serbian population, with mortality rates among the highest in the world. Basic interventions can reduce the effects of ultraviolet radiation (UVR) exposure, especially in youth, and decrease incidence and morbidity. This study is the first cross-sectional nationwide research on knowledge, attitudes, and sun exposure practices among Serbian high school students. The results revealed that fewer than 5% of students can correctly interpret the sunburn effect of a given UV index, while sun protection strategies are infrequently adopted. Most students (55.97%) expressed favorable attitudes regarding tanning, while more than half (64.48%) reported moderately high and high exposure. Females are more likely than males to expose themselves to UVR, especially intentionally. Females use protection more than males, while even 62.65% of males use protection insufficiently. The most commonly used sun protective measures were sunscreen and shade. The results indicate the necessity for innovative and age-suitable education methods and age- and gender-directed awareness campaigns for skin cancer prevention and the promotion of sun safety. Specifically, campaigns aimed at females should focus on motivating reduced intentional exposure, while those targeting males should emphasize the consistent use of sun protection measures. Full article

Melanoma, the most aggressive form of skin cancer, still represents a significant and growing public health concern. Ultraviolet radiation (UVR) is considered the primary driver of melanoma, although genetic predisposition also plays a critical role. This review explores the intricate molecular mechanisms by which UVR-induced photodamage contributes to melanoma development. We examine epidemiological evidence linking UV exposure to increased risk, detailing how UVR damage to DNA triggers inflammatory responses and impairs DNA repair mechanisms. Specifically, we discuss the roles of nucleotide excision repair (NER) and base excision repair (BER) in mitigating UV damage. The review further explores diagnostic and surgical implications for melanomas arising on sun-exposed skin. By synthesizing current evidence, this overview aims to deepen understanding of the complex relationship between UVR, photodamage, and melanoma, shedding light on the need for personalized preventive strategies to better stratify the risk and introduce behavioral changes to reduce skin photodamage. Full article