UVA Treatment Research Articles

Effect of photoactivated riboflavin on the biodegradation-resistance of root-dentin collagen

This study was conducted to evaluate the effect of UVA-activated 1% riboflavin solution on structural integrity; mechanical properties and stability; and collagenase-mediated collagen solubilisation resistance of demineralized root dentin collagen matrix. Root dentin specimens demineralized with 17% EDTA for 7days were treated with 1% RF for 1min followed by UVA photo-activation at intensity 7mW/cm2 for 1min. Control specimens were completely devoid of riboflavin and/or UVA treatments. Specimens were challenged with bacterial collagenase type-I solution for different time-periods at 37°C. Collagen solubilisation resistance was evaluated in terms of hydroxyproline (HYP) liberation. Mechanical characterization of dentin specimens before and after 24h of exposure to collagenase solution was done in terms of apparent-elastic modulus (Eappr) and ultimate tensile strength (UTS). Variations in dentin collagen-network structure with exposure time in collagenase were visualized by TEM. Crosslinking dentin with UVA-activated riboflavin significantly decreased HYP release and increased Eappr and UTS compared to control specimens with storage time in collagenase. Moreover, crosslinked specimens showed higher structural resistance to collagenase effect reflected from dense, well-formed collagen fibrils-network with characteristic collagen cross-banding. UVA-activated riboflavin treatment increased collagenase-mediated collagen degradation resistance and enhanced mechanical stability against collagenase challenges of root dentin after EDTA demineralization.

On mechanism behind UV-A light enhanced antibacterial activity of gallic acid and propyl gallate against Escherichia coli O157:H7

Possible mechanisms behind the enhanced antimicrobial activity of gallic acid (GA) and its ester propyl gallate (PG) in the presence of UV-A light against Escherichia coli O157:H7 were investigated. GA by itself is a mild antimicrobial and has a pro-oxidant ability. We found that the presence of UV-A light increases the uptake of GA by the bacteria. Once GA is internalized, the interaction between GA and UV-A induces intracellular ROS formation, leading to oxidative damage. Concurrently, GA + UV-A also inhibits the activity of superoxide dismutase (SOD), magnifying the imbalance of redox status of E. coli O157:H7. In addition to ROS induced damage, UV-A light and GA also cause injury to the cell membrane of E. coli O157:H7. UV-A exposed PG caused oxidative damage to the cell and significantly higher damage to the cell membrane than GA + UV-A treatment, explaining its higher effectiveness than GA + UV-A treatment. The findings presented here may be useful in developing new antimicrobial sanitation technologies for food and pharmaceutical industries.

726 The cytokine expression profile of mycosis fungoides and Sezary Syndrome cells after psoralen with UVA treatment

726 The cytokine expression profile of mycosis fungoides and Sezary Syndrome cells after psoralen with UVA treatment

Ultraviolet radiation reduces desmosine cross-links in elastin

Elastic fibers, a major component of the extracellular matrix of the skin, are often exposed to ultraviolet (UV) radiation throughout mammalian life. We report on an in vitro study of the alterations in bovine nuchal ligament elastic fibers resulting from continuous UV-A exposure by the use of transmission electron microscopy (TEM), histology, mass spectrometry, and solid state 13C NMR methodologies. TEM images reveal distinct cracks in elastic fibers as a result of UV-A irradiation and histological measurements show a disruption in the regular array of elastic fibers present in unirradiated samples; elastic fibers appear shorter, highly fragmented, and thinner after UV-A treatment. Magic angle spinning 13C NMR was applied to investigate possible secondary structural changes or dynamics in the irradiated samples; our spectra reveal no differences between UV-A irradiated and non-irradiated samples. Lastly, MALDI mass spectrometry indicates that the concentration of desmosine, which forms cross-links in elastin, is observed to decrease by 11 % following 9 days of continuous UV-A irradiation, in comparison to unirradiated samples. These alterations presumably play a significant role in the loss of elasticity observed in UV exposed skin.

Photolytic degradation of the β-blocker nebivolol in aqueous solution

Nebivolol (NEB) is one of the top-sold prescription drugs belonging to the third generation of beta-blockers. However, so far, occurrence data in the environment are lacking. Within this study NEB has been found for the first time in effluent samples of wastewater treatment plants in Germany with an average concentration of 13 ng L−1.Its photodegradation behavior in the environment and in technical processes is largely unknown. To fill this gap, three different UV treatment procedures (UV-C at 254 nm, UV-B at 312 nm and UV-A at 365 nm) were investigated in three different matrices: pure water, pure water in presence of the hydroxyl radical (OH) scavenger tert.-butanol and real wastewater. No elimination was observed during UV-A treatment. In contrast, NEB degradation during UV-B and UV-C treatment followed pseudo first order reaction kinetics, with highest removal rate during UV-C treatment in pure water (k = 7.8 × 10−4 s−1). The rate constant for UV-C irradiation decreased to 2.9 × 10−4 s−1 in the presence of the OH scavenger and in the presence of the wastewater matrix. The rate constant for the UV-B lamp was 4.4 × 10−4 s−1, Three transformation products were identified after UV-B and UV-C photolytic degradation using high resolution mass spectrometry. The main photoreaction is the substitution of the fluorine atoms of NEB by hydroxyl groups. A photolytic cleavage of the CF bond can be excluded as the high bond dissociation energy of aromatic CF bonds (525 kJ mol−1), exceeds the energy of electromagnetic radiation applied in the present study (≥254 nm, i.e., max. 471 kJ E−1). The quantum yields for NEB degradation for the UV-C lamp achieved in pure water, the OH scavenged system and wastewater matrix were Φdeg = 0.53, 0.19 and 0.22, respectively. For UV-B Φdeg was 0.023 ± 0.003, noticeable differences in quantum yield were not found. The photooxidation involves reactive oxygen species such as superoxide and singlet oxygen. These oxidative species may be formed upon reaction of photo-excited NEB with oxygen.

Amotosalen/UVA-Treated Platelet Components Are Efficacious in Massively Transfused Patients

▪The amotosalen/UVA process (INTERCEPT Blood System Cerus corp., CA) (IBS), is designed for the ex vivo preparation of pathogen-inactivated whole blood-derived and apheresis platelets. The system is intended to reduce the risk of transfusion-associated transmission of viruses, bacteria, and parasites, prevent transfusion-associated graft versus host disease, and may also reduce the risk of other adverse effects due to transfusion of contaminating donor leukocytes. Amotosalen/UVA treatment may be used in place of testing and/or leukoreduction for prevention of transfusion-transmitted CMV infection, and also as a replacement for bacterial culture screening. Amotosalen/UVA-treated PC have proven effective at treating and preventing bleeding in clinical trials and in routine use, however most prospective randomized studies were performed in hematology/oncology patients. We investigated efficacy during massive transfusion (MT) for active bleeding in general hospitalized patients.Amotosalen/UVA treatment was introduced at a large Austrian academic medical center for all apheresis and whole blood platelets suspended in a platelet additive solution, in January-March 2013. We investigated component use on the day(s) of the MT event, in-hospital mortality and length of stay after the event in all patients who received ≥ 1 PC and ≥ 10 red cell (RBC) components on a single day, for 21 months prior to and after universal IBS implementation.306 patients had MT on 331 days, with 11 patients receiving MT on 2 consecutive days which were analyzed as a single MT event, and 12 patients had MT events on 2 or 3 non-consecutive days. Patients were mostly male (74%) over 18 years old (304/306). 93 patients underwent liver transplant; 97 had cardiac or vascular surgery procedures, including cardiac transplant (11) and emergent aortic aneurysm repair, while 51 were treated for trauma. The remaining 65 were treated for a variety of medical and surgical indications.Based on analysis of the first MT episode, component use on the day(s) of the MT event was unchanged pre and post IBS implementation, except trauma patients used fewer RBC post IBS. The mean ratio of RBC: platelets: plasma (assuming 1 dose of platelets = 6 whole blood platelets) was close to 1:1:1, except for liver transplants who used a disproportionate amount of plasma components in both periods. In-hospital mortality and median time to discharge did not change after implementation of IBS PC, except for cardiac and vascular surgery patients who were discharged earlier in the post IBS period.The introduction of amotosalen/UVA-treated, pathogen inactivated PC did not adversely affect outcomes in massively transfused patients in terms of blood product usage, in-hospital mortality and length of stay in a range of clinical indications for platelet transfusion support. [Display omitted] DisclosuresChen:Cerus corp.: Employment. Lin:Cerus corp: Employment. Benjamin:Cerus corp.: Employment.

The impact of UVA on the glycoprotein glue of orb-weaving spider capture thread from a diurnal and a nocturnal species (Araneae: Araneidae)

We compared the effect of Ultraviolet A radiation on the adhesive droplets of the diurnal orb-web weaver Argiope trifasciata Forskaal, 1775 and the nocturnal orb-web weaver Neoscona crucifera (Lucas, 1838). We hypothesized that glycoprotein glue within A. trifasciata droplets will either be unaffected or will benefit from UVA exposure, whereas the glycoprotein of N. crucifera will be degraded by UVA. In both species, the volume of fresh droplets did not differ from that of droplets that were exposed to UVA for four hours, or from the volume of droplets kept in the dark for four hours. This documented that UVA did not affect compounds that confer droplet hygroscopicity. Both dark and UVA treatments reduced the relative toughness of droplet glycoprotein, though the reductions were not statistically significant, with the dark treatment exhibiting a greater decrease in relative toughness. This study suggests that ecologically relevant levels of UVA exposure do not affect the glycoprotein glue of orb-weaver capture silk.

Response of Growth and Development of Young Tomato Plants to End-of-day Monochromatic Light from Various LEDs

Plant growth and development strongly influenced by light quantity and its spectral composition. Young tomato plants were cultivated in growth cabinets under artificial light provided by red and blue light emitting diodes(LEDs) during 12 hours, then plants were exposed to monochromatic ultraviolet, blue, green and red lights as an end-of-day(EOD) treatment during 4 hours to study their effect on plant growth parameters. EOD lighting from various LEDs increased total fresh and dry weights as well as assimilation area compared to those in control. Blue light increased stem height, internode length and stem diameter. Monochromatic UV-A light reduced stem elongation, highly increased stomatal conductance. Compactness and health index of young tomato plants were increased in UV-A and red light treatments.

The influence of dissolved organic carbon and ultraviolet radiation on the genomic integrity of Daphnia magna

Summary Many northern freshwaters are currently experiencing a pronounced ‘browning’, that is an increase in terrestrially derived dissolved organic carbon (DOC). Chromophoric DOC offers protection against photodamage by absorbing harmful ultraviolet radiation (UVR), but may also produce free radicals and reactive oxygen species (ROS) following photoactivation. The aim of this study was to explore the combined effects of DOC and UVR on DNA integrity of limnetic zooplankton. Specifically, DNA strand breaks in the cladoceran Daphnia magna were investigated. DNA strand breaks were assessed using comet assays with treatment of individual daphnids. A four‐by‐four design was used for exposure to DOC (2·03, 5, 10 and 20 mg L−1), UVA (0, 10·8, 21·7 and 43·4 μmol m−2 s−1 at 390 nm) and their combinations. ROS production from photoactivated DOC was quantified using a modified DCFH‐DA in vitro ROS detection assay. While UVA had no effects on DNA damage above background levels (4·5–2·8%), we observed increased DNA damage in DOC treatments (4·1–9·1%). The highest increase was observed in combined DOC and UVA treatments (up to 20·2%). ROS production showed similar patterns, as simultaneous exposure to both DOC and UVA resulted in higher formation rates than exposure to DOC and UVA alone (up to 684·5 μmol L−1 vs. 5·9 to 13·1 and 27·5 to 83·9 μmol L−1, respectively). This indicates that the observed increase in DNA damage was due to ROS production of photoactivated DOC. This study showed that strong interactive effects of short‐wave radiation and DOC could have major genomic impacts on pelagic biota. With future scenarios of increased DOC, our study points towards increasing oxidative stress for ecosystems. These findings highlight an important aspect of climate change at the intersection between ecology, limnology and toxicology. A lay summary is available for this article.

Different Narrow-Band Light Ranges Alter Plant Secondary Metabolism and Plant Defense Response to Aphids.

Light of different wavelengths affects various physiological processes in plants. Short-wavelength radiation (like UV) can activate defense pathways in plants and enhance the biosynthesis of secondary metabolites (such as flavonoids and glucosinolates) responsible for resistance against certain herbivorous insects. The intensity of light-induced, metabolite-based resistance is plant- and insect species-specific and depends on herbivore feeding guild and specialization. In this study, broccoli (Brassica oleracea var. italica) plants were grown for 4weeks in a climate chamber under conventional fluorescent tubes and were additionally treated with UV-B (310nm), UV-A (365 or 385nm), or violet (420nm) lightgenerated with UV-B tubes or light-emitting diodes (LEDs). The objective was to determine the influence of narrow bandwidths of light (from UV-B to violet) on plant secondary metabolism and on the performance of the cabbage aphid Brevicoryne brassicae (a specialist) and the green peach aphid Myzus persicae (a generalist). Among flavonol glycosides, specific quercetin and kaempferol glycosides increased markedly under UV-B, while among glucosinolates only 4-methoxy-3-indolylmethyl showed a 2-fold increase in plants exposed to UV-B and UV-A. The concentration of 3-indolylmethyl glucosinolate in broccoli plants increased with UV-B treatment. Brevicoryne brassicae adult weights and fecundity were lower on UV-B treated plants compared to UV-A or violet light-treated plants. Adult weights and fecundity of M. persicae were increased under UV-B and UV-A treatments. When specific light wavelengths are used to induce metabolic changes in plants, the specificity of the induced effects on herbivores should be considered.

Effects of light-emitting diode treatments on Brevicoryne brassicae performance mediated by secondary metabolites in Brussels sprouts

Although short-wavelength light and especially UV radiation can induce resistance in plants against herbivorous insects, the optimal wavelengths, light intensities (photon flux rates), and illumination schedules for inducing resistance have not been previously determined. Light-emitting diode (LED) illumination enables researchers to subject insects and plants to narrow-banded light treatments. In this study, we assessed how the metabolite-based defense response in Brussels sprout plants (Brassica oleracea var. gemmifera) against the cabbage aphid, Brevicoryne brassicae (Hemiptera: Aphididae), was affected by the following LED-generated wavelengths of light: 300 nm (UV-B), 365 nm (UV-A), 470 nm (blue light), and 660 nm (red light). Ambient greenhouse light supplemented with light from sodium vapor lamps served as the control treatment. The results showed a significant reduction in B. brassicae performance in the UV-A treatment compared to the blue light treatment; the reduction in the UV-A treatment was accompanied by a significant increase in glucosinolate concentrations. The UV-B treatment induced significant changes in plant flavonoid concentrations but did not affect B. brassicae performance.

Antimicrobial effect of synergistic interaction between UV-A light and gallic acid against Escherichia coli O157:H7 in fresh produce wash water and biofilm

Abstract A synergistic interaction between gallic acid (GA) and UV-A light (UV-A + GA) to inactivate E. coli O157:H7 in spinach wash water and in biofilm was evaluated. A 30-min exposure to UV-A light in presence of 10 mM GA had relevant biological effect in the inactivation of E. coli O157:H7 in suspension in the absence (> 5 log(CFU/mL) ) and the presence of organic content (> 3-log(CFU/mL) in 2000 mg O2/L COD (Chemical Oxygen Demand) organic load), and resulted in ~ 80% decrease in the metabolic activity of E. coli O157:H7 biofilm. GA solutions could be recycled through at least 3-cycles of UV-A treatment without a significant loss in antibacterial effect. Catalase reduced the extent of E. coli O157:H7 inactivation from the UV-A + GA treatment suggesting that generation of hydrogen peroxide was partially responsible for the observed antimicrobial effect. The UV-A + GA treatment was also found to be effective in causing > 3 log(CFU/mL) reductions in E. coli O157:H7 on the surface of spinach leaves. UV-A + GA treatment can serve as an effective intervention in the fresh produce sanitation. Industrial relevance The results of this study show that a synergistic interaction between gallic acid (GA) and UV-A (365 nm) light is an effective treatment for sanitation of fresh produce and water used to wash fresh produce. It was also found to be effective against the E.coli O157:H7 biofilm. The attractive attributes of this technology include a relatively low cost; specific, light-triggered activity; non-toxic nature and scalability. Thus, this technology has potential to replace conventional chemical sanitizer-based sanitation approaches.

Nitrogen Gas Plasma Generated by a Static Induction Thyristor as a Pulsed Power Supply Inactivates Adenovirus.

Adenovirus is one of the most important causative agents of iatrogenic infections derived from contaminated medical devices or finger contact. In this study, we investigated whether nitrogen gas plasma, generated by applying a short high-voltage pulse to nitrogen using a static induction thyristor power supply (1.5 kilo pulse per second), exhibited a virucidal effect against adenoviruses. Viral titer was reduced by one log within 0.94 min. Results from detection of viral capsid proteins, hexon and penton, by Western blotting and immunochromatography were unaffected by the plasma treatment. In contrast, analysis using the polymerase chain reaction suggested that plasma treatment damages the viral genomic DNA. Reactive chemical products (hydrogen peroxide, nitrate, and nitrite), ultraviolet light (UV-A) and slight temperature elevations were observed during the operation of the gas plasma device. Viral titer versus intensity of each potential virucidal factor were used to identify the primary mechanism of disinfection of adenovirus. Although exposure to equivalent levels of UV-A or heat treatment did not inactivate adenovirus, treatment with a relatively low concentration of hydrogen peroxide efficiently inactivated the virus. Our results suggest the nitrogen gas plasma generates reactive chemical products that inactivate adenovirus by damaging the viral genomic DNA.

UVA-Irradiation Induces Melanoma Invasion via the Enhanced Warburg Effect

Melanoma is a malignant tumor in which UVA (320-400 nm) radiation is considered to be an important risk factor. But the role of UVA in melanoma progression toward an invasive phenotype is still not adequately investigated. For most proliferating tumor cells the preference of aerobic glycolysis has been described as the Warburg effect. Here we investigate the effect of UVA irradiation on changes in the Warburg effect and tumor progression toward invasive potential. On UVA irradiation, melanoma cell lines from initial tumors show an induction of the Warburg effect with increased glucose consumption and lactate production, which is at least partially mediated by reactive oxygen species. Associated with UVA treatment and enhanced lactic acid production, tumor-relevant proteases and in situ invasion is upregulated. Simultaneously, UVA increases intracellular concentrations of progression marker transketolase and activated protein kinase Akt, both involved in metabolic changes that increase with proliferation. Using invasion assays we show that lactic acid, resulting from the UVA enhanced and partially reactive oxygen species-mediated Warburg effect, increases the invasive potential of all melanoma cell lines investigated. Therefore, we demonstrate in melanoma cells that production of lactic acid, induced by UVA irradiation, increases invasiveness of melanoma cells via expression of tumor-relevant proteases.

553 SIG-1191: A novel hydrating Cosmetic Functional Ingredient (CFI) for suborbital hyperpigmentation (under eye dark circles)

548 Effects of a natural immune modulator on plaque psoriasis N Korman, E Baron, K Gordon, S Glazer, S Phillips and JE Bernstein 1 University Hospitals, Cleveland, OH, 2 Northwestern University, Chicago, IL, 3 Northshore University Health System, Evanston, IL and 4 Elorac, Inc., Vernon Hills, IL Background: Recognition that psoriasis (PS) is a chronic inflammatory disorder, rather than a local hyperproliferative disorder, has led to the understanding that proinflammatory cytokines contribute to the initiation and/or persistence of inflammation in PS. These cytokines and their transduction pathways, include tumor necrosis factor alpha (TNF-a), various interleukins (IL), the Janus kinases and phosphodiesterase 4. Objective: To evaluate oral administration of a natural immune modulator(NIM) to patients with plaque PS receiving concomitant treatment with biological drugs, and effects of NIM on inflammatory biomarkers in treatment-naive PS patients. Methods: Nineteen (19) adult PS patients receiving a biologic (ustekinumab (9), adalimumab (7), etanercept (3)) for at least 3mo received NIM capsules qd for 8wks. Clinical benefits were assessed by a Self-Administered Psoriasis Area Severity Index (SAPASI), a patient global, and an evaluation of body surface area (BSA). Nineteen (19) PS patients without therapy for 90 days, or biological for 1yr, received NIM for 28 days. Serum TNF-a, IL-6 and IL-12 biomarkers were measured at baseline and at 28 days. Adverse effects (AE) were solicited. Results: Baseline SAPASI scores ranged from 4-60 (mean of 16.5). These scores were reduced to a mean SAPASI of 6.7 at 8wk. Of 11 patients with a baseline SAPASI>10, 91% had an 8wk PASI 50 and 55% had an 8wk PASI 75. Patient globals demonstrated that 63% of patients were Much Better or Better. Ten (10) patients (53%) had a substantial BSA decrease in. Eleven (11) of 19 patients had a decrease in serum TNF-a levels with a mean decrease of 18.6% and 10 of the 19 patients (53%) had a 47.3% mean reduction in IL-6/IL-12 serum levels. No NIM related AE were reported. Conclusions: Addition of NIM to PS patients on biologicals can provide additional clinical benefit, and the actions of the NIM may be related to its ability to inhibit a variety of inflammatory pathways critical to PS. 549 Antioxidative Activity of CSL Extracts on normal human epidermis J Shim Department of Oriental Cosmetic Science, Semyung Univ, Jecheon, Korea (the Republic of) In this study, the antioxidative effects of CSL extracts were investigated. CSL extract has the similar antioxidant activity compared to ascorbic acid by DPPH assay. To confirm the antioxidnat effect on human epiermal keratinocyte, we treated CSL extract on UVA (5 J/cm2) treated human epidermal keratinocyte. CSL extract can enhance the expression of AQP3 and HAS2 genes. And CSL extract reduced the H2O2 production by UVA treatment. To determine the cause of antioxidnat activity on human epidermal keratinocyte, we performed realtime PCR related on antioxidnat enzymes such as SODs, catalase, and GPXs. Only GPX7 mRNA expression was enhanced by CSL extract treatment. These results mean that CSL extract have radical scaveging and inducing the expression of antioxidant enzyme especially GPX7. And component analysis of CSL extract and antioxidant activity could be applicable to new functional cosmetics.

Mass spectrometry data from proteomic analysis of human skin keratins after exposure to UV radiation.

A mass spectrometry (MS)-based proteomic methodology was employed to monitor oxidative modifications in keratins, the main constituents of human skin (“Non-invasive proteomic analysis of human skin keratins: screening of methionine oxidation in keratins by mass spectrometry” [1], “UV irradiation-induced methionine oxidation in human skin keratins: mass spectrometry-based non-invasive proteomic analysis” [2]). Human skin proteins were obtained non-invasively by tape stripping and solubilized in sodium dodecyl sulfate (SDS) buffer, followed by purification and digestion using the filter-aided sample preparation method. The tryptic peptides were then analyzed by liquid chromatography (LC)/electrospray ionization (ESI)-MS, tandem MS (MS/MS), and LC/ESI-selected reaction monitoring (SRM)/MS. The MS/MS data were generated to confirm amino acid sequences and oxidation sites of tryptic peptides D290VDGAYMTK298 (P1) and N258MQDMVEDYR267 (P2), which contain the most susceptible oxidation sites (Met259, Met262, and Met296 in K1 keratin) upon UVA irradiation [2]. Subsequently, quantitative determination of the relative oxidation levels of P1 and P1 [2] was achieved by LC/ESI-SRM/MS analyses of P1 and P2 together with their oxidized forms after exposure to UVA radiation or treatment with hydrogen peroxide (H2O2).

UV-A light treatment for controlling enzymatic browning of fresh-cut fruits

Abstract Enzymatic browning is critical in the preservation of the quality and the shelf-life of fresh-cut fruits. Non-thermal technologies such as UV radiation are emerging for controlling polyphenol oxidase (PPO) activity, the main agent responsible for browning. After determining the best operational conditions of a UV LED illuminator (2.43 · 10 − 3 Wm − 2 irradiance), the anti-browning effect of UV-A light (390 nm) treatment at 25 °C over increasing time periods up to 60 min was assessed on fresh-cut apples and pears. Color variation (ΔE) and its percent reduction (%RΔE) were measured using a colorimeter and the greatest effect was observed in apples which showed higher %RΔE values than pears (58% vs 25% after 60 min exposure, respectively). Anti-browning was found to be related to irradiance, exposure time and the fruit cultivar. Overall this study confirmed UV-A LED technology as an eco-friendly alternative to traditional approaches for reducing browning of minimally processed products. Industrial relevance Treatment of fresh-cut products with UV-A LED is not only easy and inexpensive to produce but also presents few hazards for humans. Moreover, the use of LED light sources brings many advantages such as energy savings, device durability, low environmental impact, high luminous efficiency and little thermal effect. UV-A LED technology has great potential to meet the demands of the food industry in the processing of fresh-cut fruits and vegetables. In addition it could also be considered a pre-treatment of fruits and vegetables being processed for the production of snacks.

The Effects of UV-A on Dry Rice Straw Decomposition under Controlled Laboratory Conditions

In arid and semi-arid areas, organic matter decomposition is stimulated by ultraviolet radiation. In this paper, the association between straw decomposition and UV-A exposure was evaluated. Oven-dried rice straw samples were chronically exposed to UV-A radiation and examined periodically for up to 90 days at room temperature. Scanning electron microscopy (SEM) showed that noticeable disintegration of the fiber structure occurred on the irradiated sample surface in comparison to the control. At the end of the UV-A treatment period, straw mass had decreased by 5%, and dissolved organic carbon (DOC) increased by 18%. The content of cellulose, hemicellulose, and lignin of the irradiated straw decreased by 29.3%, 14.4% and 49.3%, respectively. The marked loss of nitrogen and potassium in the exposed straw were also observed. Thermogravimetric analysis (TGA) showed that treatment with UV-A radiation tended to decrease the mass loss rate and the thermal degradation temperature of the straw biomass from 220 °C to 208 °C. Infrared spectrometric analysis (ATR-FTIR) showed that functional groups, e.g., C–OH and C–O–C, were disrupted obviously due to UV-A exposure. These results suggest that ultraviolet-A irradiation facilitates straw decomposition by direct photochemical degradation.

Nucleotide excision repair deficiency in melanoma in response to UVA.

BackgroundThe causative link between UV exposure and melanoma development is well known, however the mechanistic relationship remains incompletely characterised. UVA and UVB components of sunlight are implicated in melanomagenesis; however the majority of studies have focused on the effects of UVB and UVC light. Interestingly, melanoma tumour sequencing has revealed an overrepresentation of mutations signature of unrepaired UV-induced DNA damage. Repair of UVA-induced DNA damage is thought to occur primarily through the Nucleotide Excision Repair (NER) pathway, which recognises and repairs damage either coupled to transcription (Transcription Coupled Repair; TCR), or through global genome scanning (Global Genome Repair; GGR). Current literature suggests NER is deficient in melanoma, however the cause of this remains unknown; and whether reduced NER activity in response to UVA may be involved in melanoma development remains uncharacterised. In this study we aimed to determine if melanoma cells exhibit reduced levels of NER activity in response to UVA.MethodsMelanocyte and melanoma cell lines were UVA-irradiated, and DNA damage levels assessed by immunodetection of Cyclobutane Pyrimidine Dimer (CPD) and (6-4) Photoproduct [(6-4)PP] lesions. Expression of NER pathway components and p53 following UVA treatment was quantified by qPCR and western blot.ResultsUVA did not induce detectable induction of (6-4)PP lesions, consistent with previous studies. Repair of CPDs induced by UVA was initiated at 4 h and complete within 48 h in normal melanocytes, whereas repair initiation was delayed to 24 h and >40 % of lesions remained in melanoma cell lines at 48 h. This was coupled with a delayed and reduced induction of GGR component XPC in melanoma cells, independent of p53.ConclusionThese findings support that NER activity is reduced in melanoma cells due to deficient GGR. Further investigation into the role of NER in UVA-induced melanomagenesis is warranted and may have implications for melanoma treatment.

Potential effects of UV radiation on photosynthetic structures of the bloom-forming cyanobacterium Cylindrospermopsis raciborskii CYRF-01.

Cyanobacteria are aquatic photosynthetic microorganisms. While of enormous ecological importance, they have also been linked to human and animal illnesses around the world as a consequence of toxin production by some species. Cylindrospermopsis raciborskii, a filamentous nitrogen-fixing cyanobacterium, has attracted considerable attention due to its potential toxicity and ecophysiological adaptability. We investigated whether C. raciborskii could be affected by ultraviolet (UV) radiation. Non-axenic cultures of C. raciborskii were exposed to three UV treatments (UVA, UVB, or UVA + UVB) over a 6 h period, during which cell concentration, viability and ultrastructure were analyzed. UVA and UVA + UVB treatments showed significant negative effects on cell concentration (decreases of 56.4 and 64.3%, respectively). This decrease was directly associated with cell death as revealed by a cell viability fluorescent probe. Over 90% of UVA + UVB- and UVA-treated cells died. UVB did not alter cell concentration, but reduced cell viability in almost 50% of organisms. Transmission electron microscopy (TEM) revealed a drastic loss of thylakoids, membranes in which cyanobacteria photosystems are localized, after all treatments. Moreover, other photosynthetic- and metabolic-related structures, such as accessory pigments and polyphosphate granules, were damaged. Quantitative TEM analyses revealed a 95.8% reduction in cell area occupied by thylakoids after UVA treatment, and reduction of 77.6 and 81.3% after UVB and UVA + UVB treatments, respectively. Results demonstrated clear alterations in viability and photosynthetic structures of C. raciborskii induced by various UV radiation fractions. This study facilitates our understanding of the subcellular organization of this cyanobacterium species, identifies specific intracellular targets of UVA and UVB radiation and reinforces the importance of UV radiation as an environmental stressor.