• Korean Journal of Microbiology
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• v.39 no.1
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• pp.1-7
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• 2003

The aim of this work was to investigate the characterization and sequence of catechol 2,3-dioxygenase isolated from Delfia sp. JK-2, which could utilize aniline as sole carbon, nitrogen and energy source. In initial experiments, several characteristics of C2,3O separated with ammonium sulfate precipitation, DEAE-sepharose were investigated. Specific activity of C2,3O was approximately 4.72 unit/mg. C2,3O demonstrated its enzyme activity to other substrates, catechol and 4-methylcatechol. The optimum temperature of C2,3O was $$Cu^{2+}$^{\circ}C$, and the optimal pH was approximately 8. Metal ions such as $Ag^{+}$, $Hg^{+}$, and $Cu^{2+}$ showed inhibitory effect on the activity of C2,3O. Molecular weight of the enzyme was determined to approximately 35 kDa by SDS-PAGE. N-terminal amino acid sequence of C2,3O was analyzed as $^{1}MGVMRIG-HASLKVMDMDA- AVRHYENV^{26}$, and exhibited high sequence homology with that of C2,30 from Pseudomonas sp. AW-2, Comamonas sp. JS765, Comamonas testosteroni and Burkholderia sp. RPO07. PCR product was amplified with the primers derived from N-terminal amino acid sequence. In this work, we found that the amino acid sequence of Delftia sp. JK-2 showed high sequence homology of C2,3O from Pseudomonas sp. AW-2 (100%) and Comamonas sp. JS765 (97%).

• Korean Journal of Microbiology
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• v.33 no.3
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• pp.187-192
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• 1997

The strain producing biosurfactant was isolated from soil. The isolated strain was identified as the genus Tsukamurella through its morphological, cultural, physiological, menaquinone type, fatty acid composition characteristics. The highest biosurfactant production by Tsukamurella sp. 26A was observed after 4 days cultivation in the culture medium containing n-hexadecane 7%, $NaNO_{3}$ 0.2%, $K_2HPO_4$ 0.001%, $MgSO_{4}$ center dot $7H_{2}O$ 0.02%, $CaCl_2$ center dot $2H_{2}O$ 0.02%, yeast extract 0.02%(pH 6.8-7.0, 30^{\circ}C.$ The surface and interfacial tension of an aqueous solution reached 30 mNim and 1.5 mNim, respectively. The biosurfactant stabilized oil-in-water emulsion with a variety of hydrocarbons, edible oils and petroleum oils.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.11
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• pp.1532-1536
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• 2011

In this study, the antioxidative activity of Artemisia capillaris T. extract on the proliferation and differentiation of MC3T3-E1 cells under $H_2O_2$-induced oxidative stress was investigated in order to determine its protective effect against oxidative stress as well as its availability as an antioxidant material related to treatment of bone diseases. As a result, the total polyphenol content of A. capillaris extract was 90.10 mg/g, whereas the flavonoid content was 4.45 mg/g. A. capillaris extract increased proliferation of MC3T3-E1 cells under $H_2O_2$-induced oxidative stress, and also increased the proliferation of differentiated osteoblast cells under oxidative stress. In addition, two differentiation markers, alkaline phosphatase activity and mineralization level, in A. capillaris extract tended to increase. These results indicate that A. capillaris extract suppresses the damage to osteoblasts caused by oxidative stress, which demonstrates its availability as an antioxidant material for preventing bone diseases.

• Journal of the Korean Applied Science and Technology
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• v.34 no.3
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• pp.568-576
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• 2017

As interest in functionality and environmentally friendly cosmetics is growing in recent years, materials that use safe and effective plant extracts have been developed. Therefore, this study also attempted to check the possibility of the graviola extract, which is known to have various efficacy mainly as a health functional material as a functional cosmetic material. In order to find out the antioxidant activity of graviola, we measured total polyphenol, total flavonoid content and DPPH radical scavenging activity and measured the ROS activity inhibition effect and cytoprotective effect on oxidative stress by treating HDF with hydrogen peroxide cells at an appropriate concentration after checking cytotoxicity in HDF cells. Based on the results of this experiment, the graviola extract was found to contain as high as 26.6 mg(CA)/100g, 14.3 mg(Q)/100g of total polyphenol and flavonoid, which are the antioxidant indexes and to have the high radical scavenging activity. The cell survival rate of the HDF cells was measured, and as a result, no significant cytotoxicity was observed at all concentrations and the experiment was carried out at a concentration of $100{\mu}g/mL$ afterwards. Inhibition of ROS activity in HDF cells induced by hydrogen peroxide was measured and the concentration-dependent inhibition of ROS activity was found and the cell protection effect of graviola was measured after hydrogen peroxide was treated for 4, 24 and 48 hours. As a result, the cell protection effect as high as 89.92% was confirmed at a $25{\mu}g/mL$ concentration up to 24 hours. As these results show that the graviola extract has excellent antioxidant activity, almost no toxicity to HDF cells, an effective activity inhibitory effect on active oxygen generated by hydrogen peroxide and excellent cytoprotective effect, the possibility as various functional materials with antioxidant and cytoprotective effects was confirmed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.3
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• pp.194-198
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• 2001

The study was conducted to investigate the changes of hepatic cytochrome P450 monooxygenase system induced by dietary administration of polychlorinated biphenyls (PCBs) in the tilapia, Oreochromis niloticus. Tilapia were fed pellet with PCBs (Aroclor 1254) 0.05, 0.25 and 0.50 mg/kg body weight/day for 30 days. The dietary administration of PCBs (0.05 mg/kg) induced a significantly increased the concentration of cytochrome P450 and the activity of 7-ethoxyresorufin-O-deethylase (EROD) in the hepatopancreas at 30 days, while the augmentation of both responses was found at 20 days with a higher administration of PCBs-diet (0.25 mg/kg). However, hepatic 7-penthoxyresorufin-O-dealkylase (PROD) activity did not show any noticeable changes with the PCBs-diet 0.05-0.5 mg/kg range compared to control group during the experimental periods of 30 days in the tilapia. These results indicate that tilapia fed PCBs at the concentration of more than 0.05 mg/kg for 30 days are affected by PCBs in terms of cytochrome P450 concentration and EROD activity in the hepatopancreas.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.6
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• pp.889-896
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• 2012

In this study, simulation results of nitrogen and phosphorus removals and microbial activities for an $A_2O$ process in wastewater treatment plant are presented by using Activated Sludge Models (ASMs). Simulations were performed using pre-calibrated model and layout implemented in GPS-X simulation software. The models were used to investigate variations of SRT, water temperature, DO and C/N ratio effect on nutrients removal and microbial activity. According to the simulated results, the successful nitrification required SRT higher than 10.3 days, whereas increase of $NO_3$-N loading in the anaerobic reactor caused phosphorus release by PAOs; the effluent $NH_4$-N showed rapid change between $12^{\circ}C$(21.7 mg/L) and $13^{\circ}C$(3.2 mg/L); the effluent phosphorus was increased up to 1.9 mg/L at water temperature of $25^{\circ}C$; the DO increase was positive for heterotrophs and autotrophs growths but negative for PAOs growth; the PAOs showed low activity when C/N ratio was lower than 2.5. The experimental results indicated that the calibrated models can assure the prediction quality of the ASMs and can be used to optimize the $A_2O$ process.

• Journal of the Korean Applied Science and Technology
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• v.35 no.3
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• pp.757-767
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• 2018

In the propane dehydrogenation reaction proceeding at high temperature, the main cause of deactivation of the catalyst is coke deposition and sintering. In order to investigate the catalysts for reducing such inactivation, we have investigated the applicability of $MgAl_2O_4$ as a carrier for the catalytic dehydrogenation reaction. $MgAl_2O_4$ was prepared by Alcohthermal method at calcination temperature of 800, 900, $1000^{\circ}C$, and $Pt-Sn/MgAl_2O_4$ catalyst was prepared by supporting Pt and Sn by co-impregnation method. The reaction temperature was conducted at a high temperature of 650, $600^{\circ}C$ to confirm the thermal stability. As a result of the reaction experiment, it was confirmed that the conversion rate and yield of propane dehydrogenation reaction test were higher than that of the carrier-applied catalyst having a carrier calcination temperature of 900 and $1000^{\circ}C$, when the carrier-applied catalyst having a calcination temperature of $800^{\circ}C$ was used, It was found that the yield was higher than that of $Pt-Sn/{\theta}-Al_2O_3$ at $650^{\circ}C$. TGA, BET, XRD, CO-chemisorption, and SEM-EDS analyzes were performed for characterization. $MgAl_2O_4-800^{\circ}C$ was correlated with the relationship between good yield, Pt dispersion and low deactivation rate.

• Korean Journal of Materials Research
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• v.8 no.2
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• pp.173-178
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• 1998

$MgB_4O_7$: Tb, Tm, Dy, La, Ho and Nd phosphors have been prepared by sintering around $580^{\circ}C$ for 2 hours followed by flowing Ar gas. Activation energy and kinetic order of main peak of glow curve were studied by two methods peak shape method and initial rise method. By these methods, the estimated activation energies were $0.76\pm0.02eV$(Tb doped), $0.94\pm0.03eV$(Tm doped), $0.72\pm0.02eV$(Dy doped), respectively. The TL phosphors prepared in this work may be utilized to radiation sensor elements becaue of their high sensitivity to low energy X-ray.

• Journal of Plant Biology
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• v.35 no.1
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• pp.1-8
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• 1992

The characteristic of Cyanophyte genus SG63 is similar to that of Aphanot hece sp. The optimal growth was found with the concentration of NaCI and $MgSO_4{\cdot}7H_2O$ on the culture medium. The most optimal condition is 56%0 of NaCl (S4 medium) and 20%0 of $MgSO_4{\cdot}7H_2O$ (M2 medium). The synthesis of chlorophyll a, phycocyanin and soluble proteins is affected by the concentration of the two mineral elements in culture. Especially, the content of chlorophyll a and phycocyanin decreases on the most highly saline medium. The identified principal carotenoids are ${\beta}-carotene$, echinenone, zeaxanthin and myxoxanthophyll. The rates of concentration of protein/chlorophyll a and phycocyanin/chlorophyll a are low on the S4 medium. Inversely, these rates are the highest on the M2 medium. Accordingly, the high concentration of $MgSO_4{\cdot}7H_2O$ provoke the synthesis of phycocyanin and total proteins.oteins.

• Food Science and Preservation
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• v.22 no.3
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• pp.428-436
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• 2015

Five extraction conditions (AE, autoclave extraction; OE, oven extraction; HWSE, hot water and sonication extraction; HWASE, hot water acidified with 0.5% (v/v) acetic acid and sonication extraction; and BE, boiling extraction) were examined to compare the effects of different hot water extraction methods on the antioxidant properties of blueberries. The extraction yields of the AE, OE, HWSE, HWASE, and BE were 7.94%, 8.35%, 8.55% 9.15%, and 8.50%, respectively. The polyphenol and flavonoid contents of AE were 3.47 mg GAE/g and 1.59 mg RE/g, respectively, which were highest centents among others. Those of OE were ranked second to the highest. The total anthocyanin content of HWSE (5.29 mg/g) was significantly higher than that of others whereas that of AE showed the lowest content (0.96 mg/g). The order of ABTS radical and alkyl radical scavenging activities was as follows: AE > BE > OE > HWSE > HWASE. The antioxidant properties were considerably correspondent with the total polyphenol and flavonoid content. DPPH radical scavenging activity was quite high in HWSE, AE, and BE extraction, however, there were no significant differences among the five extraction methods in the aspect of $Fe^{2+}$ ion chelating activities. Moreover, AE showed the highest SOD activity, and protected the dermal fibroblast the best against $H_2O_2$-induced cytotoxicity. In conclusion, it was suggested that the autoclave extraction (AE) would be the most effective method for preparing blueberry hot water extracts with relatively high antioxidant activities.