• Korean Journal of Medicinal Crop Science
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• v.21 no.3
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• pp.191-196
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• 2013

The effect on the antioxidant activity and Nitric Oxide activity production inhibitory activity of Taraxacum has not been known. Therefore, phenolics and flavonoid contents were investigated from the ethanol extracts of five different Taraxacum species. The results showed that, among the five Taraxacum, T. hallaisanensis contains the highest total phenolic and flavonoid contents. When the antioxidant activity was measured by DPPH, $ABTS^+$ and reducing power activity, the free radical scavenging activity of T. hallaisanensis was also the highest among five Taraxacum species. However, measurement by CCK-8 assay in Raw264.7 cells indicated that the extracts of Taraxacum species have no effect on cell viability. Moreover, we also investigated the effect of Taraxacum species on NO scavenging activity in lipopolysaccharide (LPS)-stimulated Raw264.7 cells. The results clearly showed that Taraxacum species inhibited NO production, and the inhibitory effect of T. hallaisanensis was the strongest. The above results suggested that Taraxacum species affected the antioxidant and NO scavenging activity, and among the five species, antioxidant and NO scavenging activity assay of T. hallaisanensis was significantly higher than those of other four Taraxacum species. Therefore, T. hallaisanensis could be used as a potential drug with anti-oxidant and anti-inflammatory effect.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.1
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• pp.12-19
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• 2009

The aim of this study is to assess the antibiotic activity of Actinomyces in plaque from black stained primary teeth to Streptococcus mutans. Samples were obtained from four children, 2-6 years of age, who had black stains on all erupted primary teeth. 16 different Actinomyces spp. were isolated, and antibiotic activity test with paper disc method was done. The results were as follows, 1. No.1 and No.5 Actinomyces spp. showed the antibiotic activity to Streptococcus mutans and the activity of No.5 Actinomyces spp. could compete with that of Oxacillin. 2. No.1 and No.5 Actinomyces spp. also exhibited the antibiotic activity to Bacillus cereus, Bacillus subtilis commonly used as experimental bacteria for testing antibiotic activity. 3. For identification of No.1 and No.5 spp., PCR analysis was done. No.5 spp. matched Actinomyces viscosus at 97% level but No.1 spp. didn't match.

• IMMUNE NETWORK
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• v.5 no.4
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• pp.199-204
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• 2005

Background: ADP-ribosyl pyrophosphatases (ADPRase) has been known to catalyze the hydrolysis of ADP-ribose to ribose-5-phosphate and AMP. The role of ADPRase has been suggested to sanitize the cell by removing potentially toxic ADP-ribose. In this study, we examined the effect of nitric oxide on ADPRase activity in macrophages. Methods: ADPRase activity was measured in NO-inducing J774 cells. For in vitro experiments, recombinant human ADPRase was prepared in bacteria. Results: ADPRase activity was increased by the treatment of exogenous NO generating reagent, sodium nitroprusside (SNP), in J774 cells. The increased ADPRase activity was mediated by the post-translational modification, likely to cause cADP-ribosylation via nitrosylation of cysteine residue on the enzyme. The stimulation with endogeneous NO inducers, $TNF-{\alpha}/IFN-{\gamma}$, also increased ADPRase activity through NO synthesis. Futhermore, ADPRase activity may be mediated by the post-translational modification of ADPRase, ADP-ribosylation. Conclusion: These results indicate that NO synthesized by macrophage activation plays a critical role in the increase in ADPRase activity following ADP-ribose metabolism.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.6
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• pp.1080-1086
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• 1996

Monascus strains were isolated from Ang-Khak for the screening of antimicrobial activity. Two Monascus isolates, No.116 and No.481, were selected because they showed strong antimicrobial activity. Effect of various nutrients and incubation conditions on antimicrobial activity were different between two isolates. Strong antimicrobial activity of isolate No.116 was observed in the medium with 8% sucrose and $0.8%(NH_4)_2SO_4,$ 0.5% $KH_2PO_4and$ 0.5% $MgSO_4,$ while isolate No.481 required 8% sucrose, 1.6~2% $(NH_4)_2SO_4,$ 0.5% $MgSO_4and$ 0.5% $FeSO_4for$ the highest activity. The strong antimicroial activity was observed when both isolates were incubated on rice extract broth with initial pH of 5.3. The optiimum incubation temperature for the highest antimicrobial activity was $32.5^{\circ}C.$ With optimal conditions for the highest antimicrobial activity, isolate No.116 and No. 481 were both active for 51 hours or longer against test organisms Bacillus subtilis, Staphylococcus aureus, Listeria monocytogenes, and Enterococcus faecium.

• Journal of Life Science
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• v.10 no.6
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• pp.558-563
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• 2000

Effect of inhibitors on Vibrio parahaemolyticus cell growth and its urease activity was studied. The growth of the bacterium and the enzyme activity were inhibited by the addition of 0.02% p-hydroxymercuric benzoate, $HgCl_2$and $AgNO_3$. However, same concentration of boric acid, thallium acetate and $Pb(NO_3)_2$ did not affect the cell growth but inhibited urease activity by 25%, 29%, and 38%, respectively. Acetohydroxamic acid was the most potent inhibitor on cell growth by inhibiting 40% but did not affect urease activity. To investigate the effect of inhibitors on urease activity, urease was purified and confirmed on SDS-PAGE. The purified urease was inhibited 100% by the addition of 1 mM acetohydroxamic acid and $AgNO_3$but no inhibition was occurred by the addition of the same concentration of thallium acetate. and the addition of 0.01 mM of $HgCl_2$ and acetohydroxamic acid inhibited the purified urease activity by 39% and 24%, respectively. On 0.1 millimolar basic, acetohydroxamic acid and $HgCl_2$inhibited 4 times more active in urease inhibition than p-hydroxymercuric benzoate whereas no inhibition was occurred either thallium acetate or $Pb(NO_3)_2$.

• Journal of Ecology and Environment
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• v.29 no.2
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• pp.157-163
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• 2006

Growth of G. max treated with $NO_3^-$-N was decreased by high NaCl treatments, but $NH_4NO_3$-fed plants showed good growth with enhanced activity of antioxidative enzymes (SOD and APX). Especially, activity of APX was higher in 5 mM $NH_4NO_3$-fed plants than other types of N-supplied plants throughout the stress period. Higher SOD activity under salt stress was accompanied by increase in APX activity in 5 mM $NH_4NO_3$-fed plants. Similarly, application of calcium confirmed somewhat positive effects on growth. Salt-treated soybean plants showed the best growth response with the increase of SOD and APX activity at an additional 5 mM calcium treatment. Especially, the increase of SOD activity through the strengthened CuZn-SOD isoform was remarkable.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.1
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• pp.64-70
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• 2011

Nitrate reductase (NR) is activated by nitrogen sources (${NO_3}^-$ and ${NH_4}^+$) and irradiance. This study investigated the effects of these factors on the NR activity of Ulva pertusa (Chlorophyta) and Ecklonia cava (Phaeophyta). In addition, the ammonium (${NH_4}^+$) and nitrate (${NO_3}^-$) uptake rates of the two species were examined. U. pertusa took up most of the ${NO_3}^-$ and ${NH_4}^+$ in the medium during a 3hour incubation, while E. cava had a relatively high uptake rate after 3 hours. The NR activities of the two species were affected by the nitrogen source and irradiance and were highest when they were exposed to ${NO_3}^-$-rich medium and high irradiance. However, the patterns of NR activity differed between the two species. In ${NO_3}^-$-rich medium and high irradiance, U. pertusa achieved the highest NR activity ($2.01{\pm}0.07\;{\mu}mol$ ${NO_2}^-$ $g^{-1}$ DW $h^{-1}$) within the first 3 hours and then this activity decreased drastically. By contrast, the NR activity of E. cava ($0.36{\pm}0.04\;{\mu}mol$ ${NO_2}^-$ $g^{-1}$ DW $h^{-1}$) was constant for 12 hours. When exposed to darkness, the NR activity of U. pertusa decreased dramatically, while that of E. cava increased gradually for 12 hours. Therefore, E. cava is able to maintain NR activity during the dark because of its adequate carbohydrate reserves and substrate.

• The Korea Journal of Herbology
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• v.36 no.4
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• pp.23-30
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• 2021

Objectives : The purpose of this study was to investigate the antioxidant activities and nitric oxide (NO) production in RAW 264.7 macrophages in extract of Alisma orientale Juzep (EAOJ) and fermented extract (FAOJ) by Paenibacillus kribbensis AM49 (P. kribbensis AM49). Methods : The Alisma orientale Juzep was fermented with P. kribbensis AM49 at 37℃ for 72 hours. We measured total polyphenol and total flavonoid, DPPH radical scavenging activity, FRAP activity and reducing power by spectrometric assay in EAOJ and FAOJ at concentrations at 0.5, 1, 5, 10 mg/㎖. Positive control was used ascorbic acid. Furthermore, we examined effect of EAOJ and FAOJ on the cell viability and NO production in RAW 264.7 macrophages. Results : The total polyphenol and total flavonoids content of FAOJ were increased 9.16 mg/g, 2.59 mg/g to 12.58 mg/g, 3.45 mg/g. DPPH radical scavenging activity, FRAP activity and reducing power were dose dependently increased according to the treatment concentration (0.5, 1, 5, 10 mg/㎖) of EAOJ and FAOJ. In particular, DPPH radical scavenging activity, FRAP activity of FAOJ was significantly increased at 5, 10 mg/㎖. Reducing power of FAOJ at 10 mg/㎖ was similar to ascorbic acid at 0.1 mg/㎖. In addition, the cell viability and NO production in RAW 264.7 macrophages were significantly increased at the concentrations of 250, 500, 1000 ㎍/㎖. Conclusions : These results suggest that FAOJ by P. kribbensis AM49 has effects to antioxidant activity. In addition, the cell viability and NO production in RAW 264.7 macrophages were significantly increased.

• The Korean Journal of Pharmacology
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• v.31 no.1 s.57
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• pp.75-84
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• 1995

Acid secretion and NO synthase activity were determined in isolated gastric glands following hypoxia/reoxygenation and acidosis to investigate the involvement of NO in acid secretion. Isolated gastric glands were exposed to hypoxia (30 min)/reoxygenation (1 h) and/or to acidosis (pH 6.0 and 4.0). Acid secretion was measured by the ratio of $[^{14}C]-aminopyrine$ accumulation between intra- and extraglands. NO synthase activity was determined by percent conversion to $[^{14}C]-citrulline\;from\;[^{14}C]L-arginine$, a precursor of NO. The results indicate that dibutyryl cAMP stimulated acid secretion dose-dependently but had no effect on NO synthase activity in basal gastric glands. Hypoxia/reoxygenation significantly suppressed acid secretion both in unstimulated and stimulated gastric glands, which was exaggerated by acidosis. Constitutive NO synthase, activity, not responded to dibutyryl cAMP, was also inhibited by hypoxia/reoxygenation and acidosis. In conclusion, pathologic state of gastric mucosa such as hypoxia/reoxygenation and acidosis suppresses both acid secretion and NO release but the role of NO in acid secretion stimulated by dibutyryl cAMP in basal gastric glands is not significant.

• Journal of Environmental Science International
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• v.13 no.7
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• pp.619-626
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• 2004

We have studied the catalytic combustion of soot particulates over perovskite-type oxides prepared by malic acid method, The catalysts were modified to enhance the activity by substitution of metal into A or B site of perovskite oxide. In addition, the reaction conditions such as temperature and $O_2$ concentration were investigated. The partial substitution of alkali metals into A site in the $LaMnO_3$ catalyst, enhanced the catalytic activity in the combustion of carbon particulate and the activity was shown in the order: Cs > K > Na. For the $La_{1-x}Cs_{x}MnO_{3}$ catalysts, the catalytic activity showed the maximum value with x=0.3 but no more increase on the catalytic activity was shown with x > 0.3. For the $La_{0.8}Cs_{0.2}MnO_{3}$ catalyst, the substitution of Fe or Ni increased the ignition temperature. The ignition temperature decreased with an increase of $O_2$ concentration, however, no more increase in the catalytic activity was shown with $O_2$ concentration > 0.2. The introduction of NO into reactants showed no effect on the catalytic activity.