UVA Treatment Research Articles

The Combinations of White, Blue, and UV-A Light Provided by Supplementary Light-Emitting Diodes Promoted the Quality of Greenhouse-Grown Cucumber Seedlings

Insufficient solar light in winter inside the greenhouse may lead to a lower quality of vegetable seedlings, and supplemental light is an effective technique to solve this problem. This study evaluated the impacts of supplementary white (W)-light-emitting diodes (LEDs), ultraviolet A LEDs (UV-A), white and blue LEDs (WB), the combinations of white and UV-A LEDs (W-UVA), and white, blue, and UV-A LEDs (WB-UVA) on the leaf morphology, photosynthetic traits, biomass accumulation, root architecture, and hormone content of cucumber (Cucumis sativus L. cv. Tianjiao No. 5) seedlings grown in the greenhouse. The results indicated that supplementary LED lighting led to a decreased plant height, shorter hypocotyl length, bigger leaf area, and thicker leaf compared with those grown with solar light only, regardless of light quality. The shoot fresh weight, root fresh weight, and seedling quality index of cucumber seedlings grown under the combinations of white, blue, and UVA radiations increased by 30.8%, 3.2-fold, and 1.8-fold, respectively, compared with those grown with natural light only. However, no significant differences were exhibited in the biomass accumulation of greenhouse-grown cucumber seedlings between the control and the UVA treatment. The cellulose content and stem firmness of greenhouse-grown cucumber seedlings grown under the combinations of white, blue, and UVA radiations increased by 49.9% and 13.1%, respectively, compared with those grown under white light only. Additionally, the cytokinin content of cucumber seedlings was promoted by over 36.7% by applying supplementary light. In summary, the combinations of white, blue, and UVA radiations led to compact morphological characteristics, superior mechanical properties, and preferable growth performance, which could be applied as an available lighting strategy to obtain the desired morphological and quality properties of vegetable seedlings.

The Adjustment Strategy of Venus Flytrap Photosynthetic Apparatus to UV-A Radiation.

The objective of this study was to investigate the response of the photosynthetic apparatus of the Venus flytrap (Dionaea muscipula J. Ellis) to UV-A radiation stress as well as the role of selected secondary metabolites in this process. Plants were subjected to 24 h UV-A treatment. Subsequently, chl a fluorescence and gas exchange were measured in living plants. On the collected material, analyses of the photosynthetic pigments and photosynthetic apparatus proteins content, as well as the contents and activity of selected antioxidants, were performed. Measurements and analyses were carried out immediately after the stress treatment (UV plants) and another 24 h after the termination of UV-A exposure (recovery plants). UV plants showed no changes in the structure and function of their photosynthetic apparatus and increased contents and activities of some antioxidants, which led to efficient CO2 carboxylation, while, in recovery plants, a disruption of electron flow was observed, resulting in lower photosynthesis efficiency. Our results revealed that D. muscipula plants underwent two phases of adjustment to UV-A radiation. The first was a regulatory phase related to the exploitation of available mechanisms to prevent the over-reduction of PSII RC. In addition, UV plants increased the accumulation of plumbagin as a potential component of a protective mechanism against the disruption of redox homeostasis. The second was an acclimatization phase initiated after the running down of the regulatory process and decrease in photosynthesis efficiency.

Effects of LED Light Quality on the Growth of Pepper (Capsicum spp.) Seedlings and the Development after Transplanting

In this study, the effects of different light conditions on the growth of pepper seedlings and the development of these pepper seedlings after transplanting were explored. Based on the control light, pepper seedlings were grown under radiation with different proportions of added blue, UV-A, and far-red light for 18 days. Compared with the control, supplementation with UV-A and far-red light increased the seedling height whereas blue light decreased. Blue and UV-A treatments increased seedling compactness and the seedling index while far-red light treatments have obvious inhibitory effects. The chlorophyll content of the UV-A treated seedlings was significantly increased, but far-red light reduced the carotenoid content. Far-red light increased the activities of SOD and CAT and decreased the MDA content of seedlings. After transplanting, there was no obvious difference in the flowering time of all treated pepper plants. An increase in pepper yield was discovered when pepper seedlings were supplemented with blue and UV-A light. Overall, our results demonstrated that proper supplementation of UV-A and blue light at the seedling stage positively produces strong and healthy pepper seedlings, and could increase the yield of pepper plants after transplanting.

Effects of Algal Utilization of Dissolved Organic Phosphorus by Microcystis Aeruginosa on Its Adaptation Capability to Ambient Ultraviolet Radiation

Phosphorus (P) plays an important role in eutrophication and algal adaptation to environmental stresses; therefore, a better understanding of the impact of P is essential to control cyanobacterial bloom. In this study, Microcystis aeruginosa is treated with 5 h of ambient irradiation in the culture medium with different availabilities of dissolved organic P (DOP) and dissolved organic matter (DOM) to explore algal physiological responses. Compared to photosynthetically active radiation (PAR), ambient UV-A and UV-B radiation exerted oxidative stresses and has inhibitive effects on the growth and photosynthesis of M. aeruginosa. However, M. aeruginosa had a strong adaptation capability, and the negative effects of UV radiation can be alleviated with DOM addition in the DOP-rich medium. The adaptation of M. aeruginosa to UV radiation in the DOP-rich waters can be mainly achieved through hydrolysis of DOP and metabolism of dissolved inorganic P (DIP), and the DOP utilization behaviors of M. aeruginosa might greatly affect algal UV adaptation capability. In the DOP-rich medium without DOM, the great inactivation of algal alkaline phosphatase (APase) after UV radiation could result in worse affinity for DOP, slower DOP uptake and lower cellular P quota. Consequently, the P demand of M. aeruginosa could not be satisfied for UV adaptation processes, including decreasing UV-induced damages and promoting self-repair. However, DOM could act as an antioxidant and significantly decrease APase inactivation of UV-radiated M. aeruginosa. In the DOP-rich medium with DOM, DOP utilization by M.aeruginosa in the UV-A and UV-B treatments is promoted and algal demand for P is satisfied for its adaptation, such as enhanced production of photosynthetic pigments, increased superoxide dismutase (SOD) activity, recovery of photosynthetic efficiency, etc. Overall, our findings indicate the close relationship between algal DOP utilization and the adaptation to ambient UV radiation of typical cyanobacteria in DIP-limited and DOP-enriched natural waters.

Effects of Supplemental UV-A LEDs on the Nutritional Quality of Lettuce: Accumulation of Protein and Other Essential Nutrients

Light plays an important role in influencing the nutritional quality of food crops, especially with regard to the health-promoting phytochemicals. However, its role in affecting the nutritional quality with regard to the essential nutrients is not well understood. In this study, the effects of preharvest UV-A treatment on the nutritional quality of lettuce (Lactuca sativa, cv. red-leaf ‘New Red Fire’ and green-leaf ‘Two Star’) in relation to the essential nutrients and health-promoting phytochemicals were explored. Lettuce plants were grown in a growth chamber and were subjected to supplemental UV-A LEDs (peak wavelength 375 nm) for a brief period (3–6 days) prior to harvest. UV-A LEDs were equipped with lenses to control the light dispersion. Many growth indices such as shoot fresh mass, leaf area, and leaf number were unaffected by supplemental UV-A in both varieties while shoot dry mass decreased in response to a 6-day UV-A treatment compared to the control. Leaf chlorophyll and carotenoid concentrations increased significantly in green-leaf lettuce after 3 or 6 days of UV-A treatment, but only after 3 days of UV-A treatment in red-leaf lettuce compared to the control. Leaf protein concentration increased significantly in both lettuce varieties along with a number of essential nutrients such as phosphorus, potassium, calcium, manganese, and sulfur in response to supplemental UV-A. Supplemental UV-A increased the accumulation of protein by approximately 48% in green-leaf lettuce and 31% in red-leaf lettuce compared to the control plants. Moreover, in addition to the above essential nutrients, green-leaf lettuce accumulated higher amounts of magnesium, copper, and zinc compared to the control plants, indicating that green-leaf lettuce was more responsive to preharvest supplemental UV-A treatment than red-leaf lettuce. However, the accumulation of total phenolic compounds and flavonoids in both varieties was lower under supplemental UV-A. Furthermore, the use of LED lenses did not have a consistent impact on most of the plant responses studied. Overall, the results indicate that a brief preharvest exposure of both red- and green-leaf lettuce varieties to UV-A increased their nutritional quality by enhancing the accumulation of protein and other major essential nutrients.

Effect of Supplemental UV-A Intensity on Growth and Quality of Kale under Red and Blue Light.

Different intensities of UV-A (6, 12, 18 μmol·m−2s−1) were applied in a plant factory to evaluate the combined influences of supplemental UV-A and red and blue light (Red:Blue = 1:1 at PPFD of 250 μmol·m−2 s−1) on the biomass, antioxidant activity and phytochemical accumulation of kale. Supplemental UV-A treatments (T1: 6 μmol·m−2 s−1, T2: 12 μmol·m−2 s−1 and T3: 18 μmol·m−2 s−1) resulted in higher moisture content, higher pigment content, and greater leaf area of kale while T2 reached its highest point. T2 treatment positively enhanced the antioxidant capacity, increased the contents of soluble protein, soluble sugar and reduced the nitrate content. T1 treatment markedly increased the content of aliphatic glucosinolate (GSL), whereas T2 treatment highly increased the contents of indolic GSL and total GSL. Genes related to GSL biosynthesis were down-regulated in CK and T3 treatments, while a majority of them were greatly up-regulated by T1 and T2. Hence, supplemental 12 μmol·m−2 s−1 UV-A might be a promising strategy to enhance the growth and quality of kale in a plant factory.

Effect of combination of UV-A light and chitosan-gallic acid coating on microbial safety and quality of fresh strawberries

Strawberries can be contaminated by foodborne pathogens or mold on farm or during postharvest handling. Photo-irradiation of edible chitosan coating containing gallic acid can be an innovative antimicrobial intervention to improve the safety and shelf-life of strawberries. This study investigated antimicrobial activity of chitosan-gallic acid coating under 360 nm UV-A light. The thin layer of coating material allowed 80% of UV-A light transmission while blocking the majority of UV-C (200–280 nm) light. The formation of the coating layer was visualized by light and confocal microscopes. After 180 min exposure to UV-A, a 2.3 ± 0.4 log reduction of E. coli O157:H7 on chitosan-gallic acid (CH-GA) coated strawberries was achieved, which were significantly (P < 0.05) higher than CH, GA, and CH-GA without UV-A (average 0.3–1.0 log reductions) and UV-A. This level of inactivation was also significantly (P < 0.05) higher than GA + UV-A treatment (1.2 ± 0.4 log reductions), but not significantly different from (P > 0.05) CH + UV-A (1.8 ± 1.0 log reductions) treatment. The photo-irradiated coating did not significantly (P > 0.05) alter the mold decay incidence (%) in strawberries. Additionally, the redness and yellowness values of CH-GA + UV-A treated berries (35.4 ± 0.9, 22.0 ± 1.0) were initially lower (P < 0.05) than the control (40.5 ± 0.3, 26.1 ± 2.6), and became comparable (P > 0.05) after 14 days of storage. Comparatively, their firmness values did not show differences (P > 0.05) throughout the storage. Findings demonstrated the potential for using photo-irradiated coatings to reduce food safety risk in strawberries.

Variation of antioxidant capacity and antiviral activity of the brown seaweed Sargassum filipendula (Fucales, Ochrophyta) under UV radiation treatments

ABSTRACT Physiological responses in seaweeds are influenced by environmental conditions such as UV radiation among other abiotic factors, concerns that must be taken into account for bioprospecting purposes. The production of UV-absorbing compounds is a well-known strategy for protecting organisms against UV radiation stress as the compounds absorb and dissipate short wavelengths. Besides their natural photoprotective sunscreen value, there is strong evidence of potential use as antioxidant, anti-inflammatory, antibacterial, antifungal, antimalarial, antiproliferative, immunomodulatory and anticancer agents. Here, we studied the relationship of potential cell damage to antioxidant activity and bioactive properties of brown seaweed Sargassum filipendula under the effect of radiation treatments: PAR (control), PAR+UVA and PAR+UVB after 10 days of exposure. Cell damage was assessed as DNA impairment by the quantification of cyclobutane pyrimidine dimers (CPDs). Antioxidant potential, tested by ABTS, DPPH, FRAP and chelating activity assays and quantification of total phenolic compounds were performed using methanolic crude extracts at different concentrations. Antiviral activity was assessed by the ability of different concentrations of methanolic and aqueous extracts to inhibit retroviral reverse transcriptase (RT) activity. PAR+UVB treatment negatively affected DNA integrity, and more CDP-DNA complexes were observed. Higher antioxidant activity was observed under PAR treatment than UVA and UVB radiation treatments. There was 25–90% inhibition of the RT enzyme for methanolic extracts, while aqueous extracts showed nearly 100% inhibition for all treatments and tested concentrations. UV-absorbing compounds in S. filipendula provide adaptive advantages against UV radiation exposure. Additionally, the species can be considered as a potential biotechnology source of natural bioactive compounds, and isolation of these compounds or obtaining bioactively rich extracts will potentially be of great benefit for the development of functional bioproducts.

Mild-Intensity UV-A Radiation Applied Over a Long Duration Can Improve the Growth and Phenolic Contents of Sweet Basil.

UV-A radiation (320–400 nm) is an abiotic stressor that may be used to enhance the production of beneficial secondary metabolites in crops such as leafy vegetables. However, tradeoffs between enhanced phytochemical contents and overall growth/yield reductions have been reported. The responses varied depending on the UV-A intensity, spectral peak, exposure time, species, and varieties. We quantified the changes in growth, morphology, photosynthesis, and phenolic contents of sweet basil grown under a base red/blue/green LED light with four supplemental UV-A intensity treatments (0, 10, 20, and 30 W·m−2) in an indoor environment over 14 days. The objective was to determine whether UV-A radiation could be utilized to improve both yield and quality of high-value sweet basil in a controlled production environment. Biomass harvested at 14 days after treatment (DAT) was highest under mild-intensity UV-A treatment of 10 W·m−2 and lowest under high-intensity UV-A treatment of 30 W·m−2. The total leaf area and the number of leaves were significantly lower under the 30 W·m−2 treatment than under the 10 and 20 W·m−2 treatments at 14 DAT. The maximum quantum efficiency of photosystem II (PSII) for photochemistry (Fv/Fm) showed a gradual decrease under the 20 and 30 W·m−2 treatments from 3 to 14 DAT, whereas Fv/Fm remained relatively constant under the 0 and 10 W·m−2 treatments over the entire 14 days. The leaf net photosynthesis rate showed a significant decrease of 17.4% in the 30 W·m−2 treatment compared to that in the 10 W·m−2 treatment at 14 DAT. Phenolic contents (PAL enzyme activity, total phenolic concentration, and antioxidant capacity) were the highest under the 20 W·m−2 treatment, followed by the 10, 30, and 0 W·m−2 treatments. Overall, our results indicate that the biomass production and accumulation of beneficial phenolic compounds in sweet basil varied depending on the intensity and duration of UV-A application. Mild UV-A radiation (10–20 W·m−2) can be a beneficial stressor to improve sweet basil yield and quality over relatively long-term cultivation.

Growth and Biochemical Responses of Green and Red Perilla Supplementally Subjected to UV-A and Deep-blue LED Lights.

This study investigated the effects of UV-A and UV-A-closed visible light (deep-blue [DB]) on the growth and bioactive compound accumulation of green and red perilla. Four-week-old seedlings were cultivated in an environment control room under visible light with red, blue and white LEDs for 4 weeks and then were continuously grown under supplemental UV-A (365 nm and 385 nm) and DB (415 nm and 430 nm) lights for 7 days. UV-A and DB treatments did not enhance the growth characteristics of green perilla compared with the control; while these treatments enhanced the growth parameters of red perilla, and the values were highest in DB 415 nm. The photosynthesis rate of both cultivars showed similar trends as the growth results of each cultivar. The electron transport rate and maximum quantum yield of both cultivars were reduced under UV-A 365 nm, while these values were maintained in DB treatments. In both cultivars, total phenolic, antioxidant capacity, rosmarinic and caffeic acids and perillaldehyde levels were enhanced in DB treatments, whereas UV-A 365 nm and DB 415 nm increased the total anthocyanin content. Overall, supplemental DB 415 nm and 430 nm was suitable for improving the growth and biochemical accumulation of both perilla cultivars.

Crosslinking-Induced Corneal Endothelium Dysfunction and Its Protection by Topical Ripasudil Treatment

Purpose To investigate the changes of corneal endothelium under different crosslinking conditions and the protective effect of ripasudil. Methods Corneal crosslinking groups were infiltrated with riboflavin and subsequently irradiated with 0.54 J/cm2 or 1.08 J/cm2 UVA, while noncrosslinking groups included neither UVA nor riboflavin treatment, only 1.08 J/cm2 UVA and only riboflavin treatment. Corneal opacity, variations in corneal endothelial cells, and corneal thickness of all groups were observed by slit lamp, in vivo confocal microscopy, and optical coherence tomography. Immunofluorescence staining and scanning electron microscopy were performed to evaluate changes in the structure and function of the corneal endothelium. The mice that received a corneal crosslinking dose of 1.08 J/cm2 were instilled with ripasudil to explore its protective effect on the corneal endothelium. Results Treatment with UVA and riboflavin caused an increase in corneal opacity and corneal thickness and decreased endothelial cell density. Furthermore, treatment with UVA and riboflavin caused endothelial cell DNA damage and destroyed the tight junction and pump function of the endothelium, while riboflavin or the same dose of UVA alone did not affect the endothelium. Ripasudil reduced DNA damage in endothelial cells, increased the density of cells, and protected the endothelium's integrity and function. Conclusion Riboflavin combined with UVA can damage the corneal endothelium's normal functioning. The corneal endothelium's wound healing is dose-dependent, and the ROCK inhibitor ripasudil maintains the endothelium's pump and barrier functions.

Agronomic performance of cotton (Gossypium hirsutum L.) under the influence of UVA radiation

Cotton productivity depends on solar radiation reaching to the ground. Therefore, the present laboratory and field experiments were conducted during 2018-2019 growing seasons at the experimental station of Tashkent State Agrarian University, Uzbekistan to study UVA supplementations on growth parameters of cotton indoor and open field cultivations. Cotton (Gossipium hirsutum L. cv. “S-6524”) seeds were exposed to different doses of UV-A radiation at 340-350 nm wavelengths under a constant irradiance of 1.6 W/m2. The highest germination value (86.3%) was observed in the UVA treatment for 10 minutes. In the field condition, 10 μmol/m2/s UVA radiation intensities were given to the seeds before planting and at the true leaf formation, budding, and flowering stages of cotton, coded as UVA-2 toUVA-5 treatments. The seed germination rate was increased by 15.5% in the UVA-2 treatmentcompared to the untreated control. Furthermore, the supplemental UV-A radiation increasedoverall biomass production by 6.3 (UVA-2); 8.9 (UVA-3) and 15.1% (UVA-4), which correlated with 3.7%; 5.6% and 7.4% greater photosynthetic efficiency than those in control. All these positive changes due to the UVA intensities reflected to the cotton yields as indicated by greater values up to 10.9%, 12.3% and 15.1% in the UVA-2, UVA-3 and UVA-4 treatments, respectively. Taken together, the tested UVA supplementations enhanced the seed germination of indoor cultivation and stimulated cotton development processes of in the field condition.

The Effects of Different UVA Photoperiods on the Growth Performance, Immune Responses, Antioxidant Status and Apoptosis-Related Gene Expression of the Pacific White Shrimp (Penaeus vannamei).

UVA is the most common type of solar UV radiation in aquatic environments; however, the effects it causes in shrimp farming in recirculating water systems (RAS) is unclear. Thus, the growth performance, immune responses, antioxidant status and apoptosis-related gene expression in Pacific white shrimp, Penaeus vannamei (body weight 9.56 ± 0.10 g), reared with 12L: 12D full spectrum light as background light under five UVA (peak at 400 nm) photoperiods (0L: 24D, 2L: 22D, 4L: 20D, 8L: 16D and 12L: 12D) at a light intensity of 1 W/m2 were investigated. The results showed that the 2L: 22D and 4L: 20D UVA photoperiods enhanced the growth performance and reduced the feed conversion ratio and the shrimp mortality. Shrimp exposed to UVA (2L: 22D and 4L: 20D) also displayed higher levels of hepatopancreas catalase (CAT), superoxide dismutase (SOD), acid phosphatase (ACP), phenol oxidase (PO) and lysozyme (LZM) compared to the 8L: 16D and 12L: 12D groups. The malondialdehyde (MDA) levels increased in line with the extension of the UVA irradiation time. The mRNA expression of apoptosis-related genes in all the UVA treatments were significantly higher than with the control treatment, except for the 2L: 22D group. The results of the 2L: 22D and 4L: 20D treatments were significantly higher than those of the control group, except for LGBP. In conclusion, 2L: 22D and 4L: 20D UVA photoperiods increased growth performance and decreased FCR, improved the innate immunity and antioxidant response and reduced the mortality rate in adult shrimp.

Autophagy induction regulates aquaporin 3‐mediated skin fibroblast ageing*

Long- and short-term ultraviolet (UV) exposure have distinct biological effects on human fibroblasts. To elucidate the underlying mechanisms of the biological effects of UV exposure on human skin fibroblasts. We subjected human skin fibroblast cells with or without aquaporin 3 (AQP3), death effector domain-containing protein (DEDD) or Beclin1 manipulation to UVA treatment and evaluated autophagy and senescence in them. Short-term UVA irradiation induced autophagy and upregulated AQP3 but not senescence, whereas long-term UVA irradiation inhibited autophagy, AQP3 and trigger senescence in vitro and in vivo. Silencing AQP3 abolished short-term UVA irradiation-induced autophagy and led to cellular senescence, whereas AQP3 overexpression partially rescued the senescence and autophagy inhibition induced by long-term UVA exposure in vitro. Mechanistically, the transcription factor Jun was found to bind to the AQP3 promoter to activate its transcription following short-term UVA exposure. Subsequently, AQP3 interacted with DEDD to induce its ubiquitination-mediated degradation and promote autophagy, and bound to Beclin1 to directly activate autophagy. Finally, autophagy induced by AQP3 overexpression robustly prevented UVA-induced senescence in vitro and in vivo. Our study indicates that AQP3 controls skin fibroblast photoageing by regulating autophagy and represents a potential target for future interventions against skin ageing.

Mitigation of Particulate Matter and Airborne Pathogens in Swine Barn Emissions with Filtration and UV-A Photocatalysis

This study evaluated the use of filtration and UV-A photocatalysis for the reduction of particulate matter (PM) and airborne bacterial pathogens in swine barns. Two MERV filters (8 and 15) were used to mitigate PM concentrations measured at the PM 1, PM 2.5, respirable PM, and PM 10 ranges. Filtration was also used to generate different levels of airborne pathogens to be treated by UV-A. Results show that MERV 8 and 15 filters effectively reduced PM concentrations (96–98%) in air exhausted from a swine barn (p ranged from &lt;0.01 to 0.04). UV-A photocatalysis did not mitigate PM concentrations. UV-A photocatalysis treatment reduced measured colony-forming units (CFUs) by 15–95%. The CFU percent reduction was higher when airborne PM concentration was low. The numeric results suggested a real mitigation effect despite p-values that did not meet the usual statistical cut-off of &lt;0.05 for significance due to the large variability of the CFU control samples. Normalization of measured airborne pathogen concentrations by smaller PM size range concentrations led to emerging significant treatment differences for CFUs. A significant decrease (~51% reduction; p &lt; 0.02) in the concentration of viable airborne bacteria was shown for all PM below the 10 micron range.

Synergistic interaction of tap water-based neutral electrolyzed water combined with UVA irradiation to enhance microbial inactivation on stainless steel

As an emerging electrolyzed water (EW) technology, tap water-based neutral electrolyzed water (TNEW) is an attractive alternative to other types of conventional EW for sterilization of food contact surfaces. In this study, we sought to identify strategies for improving TNEW inactivation efficiencies of major foodborne pathogenic bacteria. We investigated the synergistic antimicrobial effect of TNEW and ultraviolet-A light (UVA) combination treatment against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on stainless steel. The data confirmed that simultaneous TNEW and UVA treatment for 60 min reduced E. coli O157:H7, S. Typhimurium, and L. monocytogenes population by 2.15, 1.55, and 2.65 log CFU/cm2, respectively. The synergistic cell count reductions in E. coli O157:H7, S. Typhimurium, and L. monocytogenes in the combination treatment group were 1.17, 0.59, and 1.62 log units, respectively. Additionally, the mechanisms of the synergistic bactericidal effects of TNEW and UVA were identified through several approaches. Mechanistic investigations suggested that the synergistic effect was associated with intracellular reactive oxygen species generation, bacterial cell membrane damage, and inactivation of dehydrogenase. These findings demonstrate that treatment with TNEW and UVA light can enhance the microbiological safety of food contact surfaces during food processing.

Ultraviolet-A light reduces cellular cytokine release from human endotracheal cells infected with Coronavirus

BackgroundAn important clinical feature of coronavirus disease 2019 (COVID-19) is hypercytokinemia (cytokine storm). We previously showed that narrow band ultraviolet-A (NB-UVA) treatment salvages coronavirus (CoV)-229E-infected human tracheal cells, and that daily endotracheal NB-UVA therapy reduced severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) levels in human subjects, with improved clinical outcomes. Here, we examined NB-UVA effects on cytokine release during CoV-229E infection. MethodsPrimary human tracheal epithelial cells were transfected with CoV-229E, then exposed to 2 mW/cm2 NB-UVA for 20 minutes every 24h, either 3 or 4 times. Secreted cytokine/chemokine levels were analyzed in supernatants collected from CoV-229E-infected/UVA-exposed cells 24h after the last UVA treatment, and from matched non-infected/UVA-exposed controls, CoV-229E-infected/non-exposed controls, and non-infected/non-exposed (naïve) controls. Metabolic pathway/downstream prediction analyses were also performed. ResultsPro-inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF), and chemokines IL-8, monocyte chemoattractant protein-1 (MCP1), and interferon gamma-induced protein 10 (IP-10), were significantly increased in CoV-229E-infected cells, and significantly decreased following NB-UVA treatment. Interferon (IFN)-α2, IFN-γ, and IL-10 were not upregulated in response to CoV-229E. Metabolic pathway predictions indicated hypercytokinemia as the top inflammatory response in CoV-229E-infected cells, whereas the top predicted pathway in CoV-229E-infected/UVA-exposed cells was the recovery stage of severe acute respiratory syndrome. ConclusionsHuman tracheal epithelial cells infected with CoV-229E showed reduced cytokine secretions including IL-6, TNF, IL-8, and MCP-1, following NB-UVA exposure. This reduction of cytokine levels in vitro, coupled with previously identified reduced cell death in CoV-229E-infected/UVA-exposed cells, suggests that determining UVA effects on cytokine storm in human SARS-Co-V2 patients is warranted.

UV-A Treatment of ZrO2 Thin Films Fabricated by Environmental Friendlier Water-Based Solution Processing: Structural and Optical Studies

An environmentally friendlier solution processing has been introduced to fabricate zirconium oxide (ZrO2) films on quartz substrates, using spin coating of simple water-based solution. The films cured with UV-A = 330 nm for different times (40, 80, 120 min) were investigated for structural and optical properties and compared with thermally annealed film (at 350 °C). XRD and Raman spectroscopy showed amorphous structure in all the samples with no significant phase transformation with UV-A exposure. AFM microscopy showed smooth and crack free films with surface roughness ≤2 nm that reduced with UV-A exposure. Ultraviolet-visible (UV–Vis) spectroscopy demonstrated optical transmittance ≥88% and energy band gap variations as 4.52–4.70 eV. Optical constants were found from spectroscopic ellipsometry (SE). The refractive index (n) values, measured at 470 nm increased from 1.73 to 2.74 as the UV-A exposure prolonged indicating densification and decreasing porosity of the films. The extinction coefficient k decreased from 0.32 to 0.19 indicating reduced optical losses in the films under the UV-A exposure. The photoluminescence (PL) spectra exhibited more pronounced UV emissions which grew intense with UV-A exposure thereby improving the film quality. It is concluded that UV-A irradiation can significantly enhance the optical properties of ZrO2 films with minimal changes induced in the structure as compared to thermally treated film. Moreover, the present work indicates that water-based solution processing has the potential to produce high-quality ZrO2 films for low cost and environmental friendlier technologies. The work also highlights the use of UV-A radiations as an alternate to high temperature thermal annealing for improved quality.

Comparative Effects of Postharvest Ultraviolet-Light Treatments on Antioxidants Properties, Nutritional and Vitamin D Contents of Some Indigenous Green Leafy Vegetables

Ultraviolet lamps irradiation has been extensively used in water treatment, surface disinfection, and as a germicidal agent. Yet, activation of some essential reactions in fruits and vegetables occurs at low doses of irradiation, which in turn leads to an improvement of their shelf-life or bioactive compounds. In this study, postharvest effects of ultraviolet irradiation at different wavelengths were investigated on antioxidants properties, nutritional and vitamin D contents of six leafy vegetables. The six vegetables were each subjected to UV-A, B, and C lamps irradiation at wavelengths of 400, 315, and 230 nm respectively in irradiation chambers. The results revealed that ultraviolet irradiation increased the phenolic and flavonoid contents with a better-reducing power ability and antioxidant capacity in tested vegetables. More also, the essential amino acid contents were significantly (P ≤ 0.05) increased. In UV-A treatment, increased nutritional and antioxidant properties were significant (P ≤ 0.05) in M. oleifera leaf extract. On the other hand, a significant (P ≤ 0.05) increase in the level of vitamin D2 and D3 synthesis in the leaves of all the vegetables was observed under UV-B treatment. The results revealed that M. oleifera leaf responds more positively to ultraviolet irradiation than other treated vegetables. Therefore, this study shows that postharvest treatments with UV-A and B lamps may be a useful biological strategy for enhancing the antioxidant and nutritional quality of vegetables. Keywords: Antioxidant activity, UV-radiation, Vegetables, Bioactive compounds, Vitamin D. DOI: 10.7176/ALST/88-04 Publication date: July 31 st 2021

Bath Psoralen Plus UVA Therapy Suppresses Keratinocyte-Derived Chemokines in Pathogenetically Relevant Cells

Psoriasis is a chronic inflammatory proliferative skin disease involving various types of chemokines regulating immune cell migration, localization, and activation. Bath psoralen plus UVA (PUVA) treatment is an established phototherapy for psoriasis, but its effects on chemokine levels remain unknown. We investigated the levels of 22 serum chemokines in 20 patients with psoriasis first treated with bath PUVA therapy between 2007 and 2011 in a single center and analyzed the associations between the chemokines and disease severity (PASI) before and after therapy to investigate the mechanisms of action of bath PUVA therapy. Before bath PUVA therapy, the PASI scores correlated with the serum levels of CCL17 (r = 0.581), CCL18 (r = 0.462), CCL19 (r = 0.477), and CXCL16 (r = 0.524). After bath PUVA, the serum levels of CCL17, CCL22, CXCL1, and CXCL9 were significantly decreased. Heatmap clustering and network analysis based on statistically significant Spearman correlations among the chemokines showed distinctive changes in the chemokine signature. Our findings revealed that the levels of several chemokines correlated with the disease state of psoriasis. Furthermore, bath PUVA therapy reduced the secretion of keratinocyte-derived chemokines that induce the migration of immune cells important for psoriasis pathogenesis, partly revealing the mechanism of the therapeutic activity.