• International Journal of Oral Biology
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• v.33 no.4
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• pp.137-141
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• 2008

The present study reports the protective properties of a total methanol extract of B. platyphylla var. japonica against ultraviolet (UV)-C irradiation. Pretreatment of Chinese hamster fibroblast (V79-4) cells with a total methanol extract significantly increased cell survival following $300\;J/m^2$ of UV-C irradiation. The total methanol extract was further fractionated into 5 fractions: n-hexane, dichloromethane, ethylacetate, n-butanol and water fractions. Among these fractions, B. platyphylla var. japonica ethylacetate, butanol and water fractions showed significant protective effects against the cellular damage induced by UV-C irradiation. In order to elucidate the mechanism underlying this protective effect, DPPH (Editor note: abbreviations should be spelled out at first use.) radical scavenging and lipid peroxidation inhibitory activity were measured. Significant radical scavenging and lipid peroxidation inhibitory activities were observed for the ethylacetate fraction. In summary, the present data demonstrate that an extract of B. platyphylla var. japonica has a significant protective effect against UV-C irradiation. The underlying mechanism of this protective effect may involve radical scavenging and inhibition of lipid peroxidation by the B. platyphylla var. japonica extract.

• Research in Plant Disease
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• v.28 no.2
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• pp.61-68
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• 2022

Powdery mildew and two-spotted spider mite are detrimental to strawberry plants and are controlled with traditional pesticides. To accommodate consumer demand, eco-friendly methods of pest control are required. Strawberries were cultivated (in soil and in a hydroponic system) for two years, and ultraviolet B (UV-B) irradiation was used as an alternative pest control during the harvesting season. Three varieties were grown (Seolhyang, Kingsberry, and Durihyang), and four UV-B lamp/mulch (black, green, and light reflection sheet [LRS]) combinations were used during harvesting: UV-B+black or green mulch, UV-B+black or green+LRS, no UV-B+black or green, and no UV-B+black or green+LRS. In all varieties, powdery mildew was 65% more controlled when UV-B irradiation was used. The adult two-spotted spider mite density was lowest in the UV-B lamp+black or green+LRS treatments. Therefore, UV-B irradiation during the strawberry harvesting season could effectively control powdery mildew and two-spotted spider mite with little side effect on the plants.

• Korean Journal of Environmental Agriculture
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• v.15 no.4
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• pp.448-454
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• 1996

This studies was carried out to know the effects of $ultraviolet-B(280{\sim}320nm)$ irradiation on the initial growth of Tilia amurensis Rupr. seedlings. UV-B irradiation inhibited the hypocotyl elongation, height growth, leaf growth, and chlorophyll formation. The inhibition was dose-dependent, and consequently those growths were more inhibited depending on the increase of UV-B levels. Morphological change such as leaf length/leaf width ratio was also observed in the leaves of irradiated seedlings. UV-B irradiation produced scorching, glazing or chlorosis, and stunting or dwarfing in the first or second leaf of the seedlings.

• Food Science and Preservation
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• v.24 no.3
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• pp.381-386
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• 2017

Ergocalciferol is known as having vitamin D activity. In this study, the effects of UV irradiation on the increase of egocalciferol content were investigated in 7 kinds of mushrooms, i.e, lily mushroom (Flammulina velutipes), oyster mushroom (Pleurotus ostreatus), young oyster mushroom (Pleurotus ostreatus), king oyster mushroom (Pleurotus eryngii), button mushroom (Agaricus bisporus), shiitake (Lentinula edodes), and wood ear mushroom (Auricularia auricula-judae). Mushrooms which were not exposed to UV light contained negligible amount of ergocalciferol in all kinds of tested mushrooms, but UV irradiation increased their content of ergocalciferol. Of UV A, B and C, UV B light was the most effective to increase ergocalciferol contents. In mushrooms, the increase in ergocalciferol content occurred only in the peel within 1 mm depth from the surface, which was directly exposed to the UV light. Therefore, when fresh whole mushrooms were irradiated with UV light, lily mushroom, the mushroom with a larger surface area compared to volume, such as lily mushroom, was more favorable in producing ergocalciferol. On the other hand when the mushrooms were freeze-dried and cut, the mushrooms with a higher ergosterol, such as king oyster mushroom, shiitake or button mushroom, were more favorable in generating ergocalciferol.

• Environmental Engineering Research
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• v.24 no.1
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• pp.54-62
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• 2019

The effects of UV wavelength and dissolved organic carbon (DOC) on the formation of dissolved gaseous mercury (DGM) were investigated in a controlled environment. To remove any other influences than UV wavelength and DOC, purified water was used as the working solution. DGM was instantly produced with irradiation of all UV lights even without DOC; whereas, there was no noticeable increase of DGM during irradiation of visible light. The amount of formed DGM increased as the DOC concentration increased even in dark conditions; however, UV-B irradiation significantly promoted DGM production with DOC present. The rate constants of reduction ranged from $1.4{\times}10^{-6}s^{-1}$ to $3.5{\times}10^{-5}s^{-1}$, with the lower values occurring under the dark condition without DOC and the higher values resulting under UV-B irradiation and high DOC concentration. However, DGM production was not linearly correlated with the DOC concentration at higher range of DOC in this study. Future studies should investigate the effects of DOC concentration on mercury (Hg) reduction over the broad range of DOC concentrations with different DOC structures and with other influencing parameters.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.7
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• pp.801-808
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• 2017

The present study investigated the protective effects of Bifidobacterium bifidum culture supernatants (BbSC) and intracellular cell-free extracts (BbICFE) on human dermal fibroblasts (HDFs) against ultraviolet-B (UV-B) irradiation. HDFs were treated with UV-B, UV-B+BbCS, and UV-B+BbICFE. Treatment of UV-B-irradiated HDFs with BbCS and BbICFE significantly increased cell viability compared to UV-B-irradiated HDFs. BbCS treatment reduced senescence in HDFs by approximately 40.0%. Moreover, sub-G1 phase was significantly reduced in BbCS- and BbICFE-treated HDFs (3.3% and 4.5%, respectively). The effect of UV-B on oxidative damage of HDFs was measured by dichlorofluorescin diacetate. Fluorescence intensity significantly increased in UV-B-irradiated HDFs. Inhibition of cellular reactive oxygen species in HDFs treated with 0.01% BbCS was the highest at 34.1%. Levels of p21 and p53 protein expression induced by UV-B irradiation were reduced by treatment with BbCS and BbICFE (47.0% and 35.6%, respectively). These results show that BbCS and BbICFE reduce UV-B-induced cellular senescence and apoptosis in HDFs. Thus, BbCS and BbICFE can be used as potential agents for protection of UV-B-induced skin cell damage.

• Korean Journal of Microbiology
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• v.49 no.2
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• pp.191-194
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• 2013

The fresh fruit bodies of Pleurotus eryngii var. ferulae was irradiated with ultraviolet (UV)-B (280-320 nm) in order to increase vitamin $D_2$ contents, which was assayed using HPLC (Waters 1525, USA). The vitamin $D_2$ contents were $3.5{\mu}g/g$ after 3 min UV-B irradiation ($21.6KJ/m^2$) and $6.02{\mu}g/g$ after 5 min UV-B irradiation ($36KJ/m^2$), respectively, which showed the significant increase considering the vitamin $D_2$ content ($0.01{\mu}g/g$) before UV-B irradiation. This increasing effect was confirmed also for other edible mushrooms; Pleurotus eryngii, from $0.09{\mu}g/g$ to $2.75{\mu}g/g$ (3 min) and $5.21{\mu}g/g$ (5 min); Lentinus edodes, from $0.021{\mu}g/g$ to $3.02{\mu}g/g$ (3 min) and $3.78{\mu}g/g$ (5 min); Pleurotus ostreatus, from $0.19{\mu}g/g$ to $9.63{\mu}g/g$ (3 min) and $11.6{\mu}g/g$ (5 min). Although the original content of vitamin $D_2$ was the highest in P. ostreatus, the extent of increase by UV irradiation was remarkably high in P. eryngii var. ferulae.

• Journal of Mushroom
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• v.19 no.4
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• pp.329-335
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• 2021

This experiment was conducted to investigate the changes in freshness parameters and determine the optimal UV-B irradiation conditions for each storage period for Heuktari, an oyster mushroom cultivar, grown under LED lightNo significant changes were observed in the CO₂ and O₂ content until day 12 of storage; however, after day 15, the CO₂/O₂ ratios were higher in the UV-treated groups than in the untreated groups. No color difference was observed between the UV-treated and untreated groups. In all UV-treated groups, hardness decreased over time; however, the group irradiated for 15 minutes showed higher hardness values than those of the untreated group. The UV-irradiated group showed higher ergosterol content than did the untreated group, and scanning electron microscopy revealed that mushroom cell wall destruction increased with increased UV treatment time. Overall, these findings confirmed that UV-B irradiation increased the ergosterol content of Heuktari but decreased its freshness and negatively impacted other storage characteristics.

• Horticultural Science & Technology
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• v.30 no.5
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• pp.493-500
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• 2012

In order to confirm the possibility of UV utilization as a means for disease protection in grapevine the stilbene contents and the disease incidence in UV irradiated leaves were investigated. UV irradiation significantly increased the contents of resveratrol, piceatannol and piceid, in them, resveratrol and piceid showed in vitro inhibition of spore germination and mycelium growth of Botrytis cinerea. The accumulation of both the stilbenes in UV irradiated leaves seems to be enough to inhibit the B. cinerea growth, since the formation of necrotic spot on the leaves was considerably inhibited when they were inoculated with the conidial spores of B. cinerea. However the stilbenes were accumulated only in the leaves exposed directly to UV showing a limited translocation ability of the compounds. Thus it would be necessary to develop a method to evenly irradiate the entire crown of plant with UV in order to expect to protect them from disease by UV irradiation.

• Membrane and Water Treatment
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• v.8 no.3
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• pp.211-223
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• 2017

In this work, an attempt was made to compare the effects of UV irradiation on the intrinsic and separation properties of membranes made of two different polymeric materials, i.e., polyvinylidene fluoride (PVDF) and polyetherimide (PEI). The changes on membrane structural morphologies and chemical characteristics upon UV-A exposure (up to 60 h) were studied by FESEM and FTIR, respectively. It was found that cracks and fractures were detected on the PVDF-based membrane surface when the membrane was exposed directly to UV light for up to 60 h. Furthermore, the mechanical strength and thermal stability of irradiated PVDF-based membrane was reported to decrease with increasing UV exposure time. The PEI membrane surface meanwhile remained almost intact throughout the entire UV irradiation process. Filtration experiments showed that the permeate flux of UV-irradiated PVDF membrane was significantly increased from approximately 11 to $16L/m^2.h$ with increasing UV exposure time from zero to 60 h. Oil rejection meanwhile was decreased from 98 to 85%. For the PEI-based membrane, oil rejection of >97% was recorded and its overall structural integrity was marginally affected throughout the entire UV irradiation process. The findings of this work showed that the PEI-based membrane should be considered as the host for photocatalyts incorporation if the membrane was to be used for UV-assisted wastewater treatment process.