• Journal of Environmental Science International
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• v.19 no.12
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• pp.1323-1334
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• 2010

The effect of nitric oxide (NO) on antioxidant system and protective mechanism against oxidative stress under UV-B radiation was investigated in leaves of maize (Zea mays L.) seedlings during 3 days growth period. UV-B irradiation caused a decrease of leaf biomass including leaf length, width and weight during growth. Application of NO donor, sodium nitroprusside (SNP), significantly alleviated UV-B stress induced growth suppression. NO donor permitted the survival of more green leaf tissue preventing chlorophyll content reduction and of higher quantum yield for photosystem II than in non-treated controls under UV-B stress, suggesting that NO has protective effect on chloroplast membrane in maize leaves. Flavonoids and anthocyanin, UV-B absorbing compounds, were significantly accumulated in the maize leaves upon UV-B exposure. Moreover, the increase of these compounds was intensified in the NO treated seedlings. UV-B treatment resulted in lipid peroxidation and induced accumulation of hydrogen peroxide ($H_2O_2$) in maize leaves, while NO donor prevented UV-B induced increase in the contents of malondialdehyde (MDA) and $H_2O_2$. These results demonstrate that NO serves as antioxidant agent able to scavenge $H_2O_2$ to protect plant cells from oxidative damage. The activities of two antioxidant enzymes that scavenge reactive oxygen species, catalase (CAT) and ascorbate peroxidase (APX) in maize leaves in the presence of NO donor under UV-B stress were higher than those under UV-B stress alone. Application of 2-(4-carboxyphenyl)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3- oxide (PTIO), a specific NO scavenger, to the maize leaves arrested NO donor mediated protective effect on leaf growth, photosynthetic pigment and free radical scavenging activity. However, PTIO had little effect on maize leaves under UV-B stress compared with that of UV-B stress alone. $N^{\omega}$-nitro-L-arginine (LNNA), an inhibitor of nitric oxide synthase (NOS), significantly increased $H_2O_2$ and MDA accumulation and decreased antioxidant enzyme activities in maize leaves under UV-B stress. This demonstrates that NOS inhibitor LNNA has opposite effects on oxidative resistance. From these results it is suggested that NO might act as a signal in activating active oxygen scavenging system that protects plants from oxidative stress induced by UV-B radiation and thus confer UV-B tolerance.

• Journal of Life Science
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• v.34 no.4
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• pp.236-244
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• 2024

Melanin is a natural pigment found in most plants and animals, and it is involved in determining the color of the skin and hair. Melanogenesis is a reactive occurrence in melanocytes aiming to protect the skin from external stimuli, such as ultraviolet rays. Tyrosine is involved in the biosynthesis of the substrate tyrosine into melanin. However, melanin overproduction can lead to skin diseases, such as melasma, blotching, hyperpigmentation, and skin cancer. Although many studies have been conducted on whitening substances, such as kojic acid and arbutin, some countries have banned or refrained from using them due to their side effects. Therefore, this study assessed the potential of horseradish (HR) as a new whitening agent in cosmetic products. For efficient extraction, subcritical water extraction was conducted. The results showed that the horseradish subcritical water 200℃ (SW 200) extract showed high DPPH radical scavenging ability, total phenolic contents (TPC), inhibiting tyrosinase activity and inhibiting melanin production of B16-F10 melanoma cell lines. To investigate its cytotoxicity to the B16-F10 melanoma cell lines, MTT reduction assay and morphological changes were observed. No cytotoxicity was found in horseradish methanol extract and SW 200. In conclusion, this research suggests the possibility of horseradish subcritical water may be useful as a natural whitening ingredient to be used in cosmetic products.

• Journal of Life Science
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• v.21 no.10
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• pp.1377-1384
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• 2011

Astaxanthin (ATX) is a red-orange carotenoid pigment that occurs naturally in a wide variety of living organisms. In this study we investigated the inhibitory effects of ATX on the induction of inducible nitric oxide synthase (iNOS), nitric oxide (NO), proinflammatory cytokines, nuclear factor-kappa B(NF-${\kappa}B$) and reactive oxygen species (ROS) in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. In addition, we tested the superoxide radical scavenging activity of ATX by scavenging assay. iNOS and NF-${\kappa}B$ expressions were determined by immunoblot analysis. Interleukin (IL)-6 and tumour necrosis factor-${\alpha}$ (TNF-${\alpha}$) were assayed by ELISA. NO production was monitored by measuring the amount of nitrite. ROS was examined by using the 2', 7'-Dichlorodihydrofluorescin diacetate (DCFH-DA) method. At a concentration of 100 ${\mu}M$, ATX inhibited the expression level of LPS-induced NF-${\kappa}B$, as well as the production of LPS-induced NO and proinflammatory cytokines (IL-6 and TNF-${\alpha}$), by suppressing iNOS expression. In particular, the maximal inhibition rate of IL-6 and TNF-${\alpha}$ production by ATX (100 ${\mu}M$) was 65.2----- and 21.2-----, respectively. In addition, ATX inhibited the LPS-induced transcriptional activity of NF-${\kappa}B$, and this was associated with suppressing the translocations of NF-${\kappa}B$ from the cytosol to the nucleus. Moreover, at various concentrations (25-100 ${\mu}M$), ATX inhibited the intracellular level of ROS. At a concentration of 5 mg/ml, the superoxide radical scavenging activity of ATX was 1.33 times higher than ${\alpha}$-tocopherol of the same concentration. These results showed that ATX inhibited the expression of iNOS and the production of NO and proinflammatory cytokines resulting from ROS production and NF-${\kappa}B$ activation in macrophages. Furthermore, ATX was found to be more effective in superoxide radical scavenging activities compared to ${\alpha}$-tocopherol. These findings are expected to strengthen the position of ATX as anti-inflammatory medicine and antioxidant.

• Journal of Environmental Impact Assessment
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• v.10 no.2
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• pp.109-121
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• 2001

Water environment and freshwater algae were studied in the upstream of the Tamjin River Dam. Among the environmental factors, DO concentration in the Tamjin River ranged from 9.0 mg $O_2/l$ to 9.2 mg $O_2/l$, pH from 7.0 to 7.1 and conductivity from $98{\mu}S/cm$ to $100{\mu}S/cm$. Average concentration of $NH_4$ and $NO_3$ ranged from $40{\mu}g\;N/l$ to $56{\mu}g\;N/l$ and from $489{\mu}g\;N/l$ to $611{\mu}g\;N/l$, respectively. $NO_3$ was more plentiful above 9~15 fold than that of $NH_4$. Average concentrations of soluble reactive phosphorus and soluble reactive silicon were $2{\mu}g\;P/l$ and 1.6 mg Si/l, respectively. Particulaly, Si nutrient increased by heavy rain events during summer season. The ratios of N/P and Si/P ranged from 248 to 261 and from 640 to 740, respectively. It is assumed that P would be limiting nutrient on the freshwater algal growth. Average content of planktonic chlorophyll-a ranged from $5{\mu}g/l$ to $13{\mu}g/l$. Mean contents of chlorophyll-a, phaeo-pigment and ash-free dry matter of periphyton were $50.3mg/m^2$, $11.9mg/m^2$, $11.5g/m^2$ in the main stream and $30.1mg/m^2$, $5.6mg/m^2$, $7.8g/m^2$ in the tributary. By comparison of the epilithon biomass, the main stream was higher with 1.5~2.1 fold than the tributary. The impotant algae were composed of diatom Achnanthes linearis, A. minutissima, Fragilaria crotonensis, Gomphonema gracile, Tabellaria flocculosa and blue-green algae Microcystis aeruginosa. In the relative abundance of the phytoplankton and epilithon, the serial dominance were diatom > green algae > blue-green algae, and diatoms were very abundant in comparison with other algal phylum.

• Food Science of Animal Resources
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• v.28 no.2
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• pp.171-180
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• 2008

This study was conducted to investigate the meat quality characteristics of pork loin in 3 crossbred groups (30 pigs/group). The crossbreeds were LY female${\times}$D male, Y female${\times}$B male and L female${\times}$B male (L: Landrace, Y: Yorkshire, B: Berkshire, D: Duroc). Pork loins were collected from animals ($110{\times}120kg$ body weight) slaughtered in a commercial slaughter house and stored at $-3^{\circ}C$. Samples were analyzed for general composition, physico-chemical properties, meat and fat color, texture characteristics, sensory evaluation and fatty acid composition at 24 hrs postmortem, and TBARS (Thiobarbituric Acid Reactive Substances) values were determined at various storage times. The LYD pigs showed a higher back fat thickness than the YB and LB pigs. There were no significant differences in intramuscular fat, intermuscular fat, subcutaneous fat and springiness among the 3 crossbreeds. In addition, there were no significant differences in general composition, pH, drip loss, cooking loss and cooked sensory evaluation among the 3 crossbreeds (p>0.05). The shear force value of LB pork was significantly lower than other crossbreeds (p<0.05). Total heme pigment was significantly higher in YB pork compared to LYD and LB pork (p<0.05). The TBARS value of YB pork was significantly lower than that of LYD pork, except after the I day of storage (p>0.05). TBARS values increased significantly during storage for all three crossbreeds. The lightness (CIE L) of YB pork was significantly lower, while the redness (CIE a) was significantly higher in YB pork relative to the other crossbreeds. With regard to textural properties, the hardness and adhesiveness values were significantly lower in YB pork compared to LB pork. In fresh meat, the color of YB pork was significantly higher than the other breeds (p<0.05). The content of myristic acid (C14:0) was significantly lower, while the content of arachidonic acid (C20:4) was significantly higher in LB pork (p<0.05). These results show that the YB breed has the highest quality meat of the three crossbreeds.