• Mycobiology
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• 제44권3호
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• pp.162-170
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• 2016

In this paper, we demonstrate the ability of Arabidopsis thaliana to detect different mixtures of volatile organic compounds (VOCs) emitted by the common indoor fungus, Aspergillus versicolor, and demonstrate the potential usage of the plant as a bioindicator to monitor fungal VOCs in indoor air. We evaluated the volatile production of Aspergillus versicolor strains SRRC 108 (NRRL 3449) and SRRC 2559 (ATCC 32662) grown on nutrient rich fungal medium, and grown under conditions to mimic the substrate encountered in the built environment where fungi would typically grow indoors (moist wallboard and ceiling tiles). Using headspace solid phase microextraction/gas chromatography-mass spectrometry, we analyzed VOC profiles of the two strains. The most abundant compound produced by both strains on all three media was 1-octen-3-ol. Strain SRRC 2559 made several terpenes not detected from strain SRRC 108. Using a split-plate bioassay, we grew Arabidopsis thaliana in a shared atmosphere with VOCs from the two strains of Aspergillus versicolor grown on yeast extract sucrose medium. The VOCs emitted by SRRC 2559 had an adverse impact on seed germination and plant growth. Chemical standards of individual VOCs from the Aspergillus versicolor mixture (2-methyl-1-butanol, 3-methyl-1-butanol, 1-octen-3-ol, limonene, and ${\beta}-farnesene$), and ${\beta}-caryophyllene$ were tested one by one in seed germination and vegetative plant growth assays. The most inhibitory compound to both seed germination and plant growth was 1-octen-3-ol. Our data suggest that Arabidopsis is a useful model for monitoring indoor air quality as it is sensitive to naturally emitted fungal volatile mixtures as well as to chemical standards of individual compounds, and it exhibits relatively quick concentration- and duration-dependent responses.

• 한국축산식품학회지
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• 제31권4호
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• pp.609-616
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• 2011

전통발효식품으로부터 L. monocytogenes ATCC 19114에 강한 항균활성을 보이는 균주를 분리하였다. 분리된 균주의 형태학적 및 생화학적 특성과 16S rRNA 염기서열 분석을 통해 Lactobacillus salivarius LCH1227으로 동정되었다. L. salivarius LCH1227이 분비하는 항균물질은 L. monocytogenes 뿐만 아니라 vancomycin-resistant Enterococcus faecalis, Streptococcus agalactiae, Bacillus cereus, Lactobacillus fermentum 등과 같은 그람양성 세균에 대해 폭 넓은 항균 활성을 나타내었다. L. salivarius LCH1227의 생육에 따른 항균 활성을 측정한 결과, 생장정체기 초기에 최대 활성(300 AU/mL)을 나타내었고, 생장정체기 이후부터 활성이 점차 감소하였다. 항균물질의 활성은 pH 2-12 구간에서 비교적 안정하였으며, 열처리에 의해서도 활성이 소실되지 않아 열에 안정한 물질임을 알 수 있었다. L. salivarius LCH1227이 생산하는 항균물질은 단백질 분해효소 처리 후에 활성이 실활됨으로써 단백질성 물질인 것으로 추정되었으며, Tricine-SDS-PAGE 실험을 통하여 항균물질의 분자량은 약 5 kDa 정도임을 알 수 있었다.

• 상하수도학회지
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• 제21권6호
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• pp.679-687
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• 2007

Nanoscale zero valent ion (nZVI) technology is emerging as an innovative method to treat contaminated groundwater. The activity of nZVI is very high due to their high specific surface area, and supporting this material can help to preserve its chemical nature by inhibiting oxidation. In this study, nZVI particles were attached to granular ion-exchange resin through borohydride reduction of ferrous ions, and chemical reduction of nitrate by this material was investigated as a potential technology to remove nitrate from groundwater. The pore structure and physical characteristics were measured and the change by the adsorption of nZVI was discussed. Batch tests were conducted to characterize the activity of the supported nZVI and the results indicated that the degradation of nitrate appeared to be a pseudo first-order reaction with the observed reaction rate constant of $0.425h^{-1}$ without pH control. The reduction process continued but at a much lower rate with a rate constant of $0.044h^{-1}$, which is likely limited by mass transfer. To assess the effects of other ions commonly found in groundwater, the same experiments were conducted in simulated groundwater with the same level of nitrate. In simulated groundwater, the rate constant was $0.078h^{-1}$ and it also reduced to $0.0021h^{-1}$ in later phase. The major limitation in application of ZVI for nitrate reduction is ammonium production. By using a support material with ion exchange capacity, the problem of ammonium release can be solved. The ammonium was not detected in the batch test, even when other competitive ions such as calcium and potassium existed.

• 한국수산과학회지
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• 제37권3호
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• pp.192-196
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• 2004

The in vitro effect of bisphenol A (BPA) on ovarian steroidogenesis of the longchin goby (Chasmichthys dolichognathus) was investigated. Oocytes taken during the maturing phase (vitellogenic, fully vitellogenic or germinal vesicle breakdown stage) were incubated with BPA (100 ng/mL) in the presence of exogenous precursor $^{3}H-17\alpha\;hydroxyprogesterone\;(^{3}H-17\alphaOHP).$ Steroids were extracted from the media and the isolated oocytes, and the extracts were separated and identified by thin layer chromatography and gas chromatography-mass spectrometry. The identities of the major metabolites were progestogens $[17{\alpha}-hydroxy,20{\alpha}-dihydroprogesterone\;(17{\alpha}20{\alpha}OHP)\;and\;17{\alpha}-hydrxy,20{\beta}-dihydroprogesterone\;(17{\alpha}20{\beta}OHP),$ androgens [androstenedione (A4) and testosterone (T)] and estrogens [estrone $(E_1)\;and\;estradiol-17{\beta}(E_2)].$ BPA treatment inhibited production of estrogens in all the maturing phases and progestogens in the germinal vesicle migrating stage. Percentage yield of estrogens was decreased with increased yield of androgens. In conclusion, BPA had an inhibitory effect on the conversion of $^3H-17\alphaOHP$ to estrogens and progestogens. These results demonstrate that BPA can act either estrogenic or anti-estrogenic effects.

• Journal of Microbiology and Biotechnology
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• 제2권3호
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• pp.189-196
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• 1992

A $\alpha$-l, 4-D-glucan maltohydrolase $(\beta$-amylase), secreted by the mesophilic aerobic bacterium Bacillus polymyxa No.26, was purified and characterized. The enzyme production was increased after a logarithmic phase of bacterial growth and paralleled with the onset of bacterial sporulation. By applying anion exchange chromatography and gel filtration the enzyme was purified 16.7-fold and had a specific activity of 285.7 units/mg. Two enzyme activities were eluted on a column of DEAE-Sephadex chromatography, and they were designated as E-I for a major enzyme peak and E-II for a minor peak. Of them, E-I enzyme peak was further purified by using gel chromatography. The molecular mass of this enzyme was determined to be 64, 000 daltons and consisted of a single subunit, showing an isoelectric point of 8.9. The enzyme was able to attack specifically the $\alpha$-l, 4-glycosidic linkages in soluble starch and caused its complete hydrolysis to maltose and $\beta$-limited dextrin. This amylolytic enzyme displayed a temperature optimum at $45^\circ{C}$ and a pH optimum at 7.0. The amino acid composition of the purified enzyme was quite similar to the other bacterial $\beta$-amylases reported. Surprisingly, the purified enzyme from this aerobe only exhibited hydrolytic activity on soluble starch, not on starch granules. The degradation of from starch by $\beta$-amylase was greatly stimulated by pullulanase addition. These results differentiated from other $\beta$-amylases reported. Based on a previous result that showed the enzyme system involves in effective degradation of raw starch granules, this result strongly suggested that the purified enzyme (E-I) can be a synergistic part of starch granule-digestion and E-II plays a crucial role in digestion of starch granules.

• 생명과학회지
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• 제6권2호
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• pp.135-141
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• 1996

양식을 위한 먹이사료로서 가능성 있는 효모균주를 연구하였다. Kluyveromyces fragilis효모와 Candida utilis 효모의 최대 비증식 속도와 바이오매스 효율은 Saccharomyces cervisiae 효모에 비하여 굉장히 높은 값을 나타내었다. 따라서, 이 연구는 대량생산을 위하여, 플라스크 배양을 통한 이들 두 효모균들의 성장특성에 그 초점을 맞추었다. 5% 접종량을 가지고 실험한 결과, 가장 좋은 $\mu$$_{max}$ 와 OD$_{max}$ 값들은 K, fragilis는 2.5% fructose 배지에서, C. utilis는 2% YE배지에서 각각 얻었으며, 이 때의 이 값들은 K. fragilis는 0.73 hr$^{-1}$1 와 3.00을 C. uitilis는 0.59 hr$^{-1}$ 와 2.80으로 밝혀졌다. 또한, 아연과 염의 초기종도가 증가할수록 균성장에 있어서의 우도기는 증가하였으며, 접종량이 증가할수록 유도가는 감소하였다. 두 효모균은 3.5% 염농도에서 비교적 잘 자랄 수 있었으며, C. utilis 효모균만이 아연을 이용할 수 있었다.

• 한국토양비료학회지
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• 제49권3호
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• pp.242-250
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• 2016

Veterinary antibiotics (VAs) has been used to treat animal disease and to increase animal weight as growth promoter. However, abused usage of VAs can cause production of antibiotic resistance genes (ARGs) in the environment and additionally, residual of VAs in soil can be transferred into crops. Therefore, main objective of this research was to examine bioaccumulation of VAs in sprouts (red cabbage, Brassica Olearacea L. var. Capitata f. rubra and red radish, Raphanus sativus) with hydroponic method. Total of 7 VAs in 2 different classes of VAs (tetracyclcines: tetracycline, oxytetracycline, chlortetracycline, sulfonamides: sulfamethoxazole, sulfamethazine, sulfamethiazole, macrolides: tylosin) were evaluated and experiment was conducted with solid phase extraction (SPE)/high performance liquid chromatography tandem mass spectrometry (HPLC/MS/MS). Initial spiked concentration of 7 VAs was $5mg\;L^{-1}$ and cultivation period was 8 days. Result showed that growth of sprouts was inhibited about 23-27% when VAs was introduced. Amount of bioaccumulated VAs was also differed depending on class of VAs. The highest amount of bioaccmulated VAs was tetracycline and sulfamethoxazole in each class with a concentration of 4.05, $7.73mg\;kg^{-1}$ respectively. Calculated transfer ratio of VAs into crops was also ranged 0.38-54.27%. Overall, bioaccumulation of VAs in crops can be varied depending on crop species and class of VAs. However, further research should be conducted to verify bioaccumulation of VAs in crops in the soil environment.

• 한국군사과학기술학회지
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• 제20권4호
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• pp.491-496
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• 2017

The hydrogen($H_2$) is promising energy carrier of renewable energy in the microgrid system such as small village and military base due to its high energy density, pure emission and convenient transportation. $H_2$ can be generated by photocatalytic water splitting, gasification of biomass and water electrolysis driven by solar cell or wind turbine. Solid oxide electrolysis cells(SOECs) are the most efficient way to mass production due to high operating temperature improving the electrode kinetics and reducing the electrolyte resistance. The SOECs are consist of nickel-yttria stabilized zirconia(NiO-YSZ) fuel electrode / YSZ electrolyte / lanthanum strontium manganite-YSZ(LSM-YSZ) air electrode due to similarity to Solid Oxide Fuel Cells(SOFCs). The Ni-YSZ most widely used fuel electrode shows several problems at SOEC mode such as degradation of the fuel electrode because of Ni particle's redox reaction and agglomeration. Therefore Ni-YSZ need to be replaced to an alternative fuel electrode material. In this study, We studied on the Double perovskite $PrBrMnO_{5+{\delta}}$(PBMO) due to its high electric conductivity, catalytic activity and electrochemical stability. PBMO was impregnated into the scaffold electrolyte $La_{0.8}Sr_{0.2}Ga_{0.85}Mg_{0.15}O_{3-{\delta}}$(LSGM) to be synthesized at low temperature for avoiding secondary phase generated when it exposed to high temperature. The Half cell test was conducted at SOECs and SOFCs modes.

• 한국응용과학기술학회지
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• 제25권2호
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• pp.211-218
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• 2008

The performance of positive plates depends on the structure of the lead dioxide active mass. The positive active materials (PAM) consists of a skeleton, built up of agglomerates and macropores. Agglomerates, in their turn, comprise particles and micropores. This paper described a study conducted to determine the effects of different soaking times between the acid fill and formation stages of the tubular plate production. For the positive plates a lead oxide were filled into tubular bag with a red lead. After filling the positive plates were soaked in $H_2SO_4$ solution. X-ray diffraction(XRD), scanning electron microscopy(SEM) and electrical testing had been used to study the compositional and morphological aspects of the positive active material(PAM) just prior and after formation. Results indicate that PAM compositions were effected by the soaking time and acid density of $H_2SO_4$ solution. It can be seen that as the soaking time duration increases, $\alpha$-PbO, $Pb_3O_4$, and Pb were all gradually sulphating. Composition of 3BS reached a maximum at around 3 h duration and $H_2SO_4$ of sp. gr. 1.10 on soaking. This results would suggest that the most beneficial conditions for soaking were the $H_2SO_4$ of sp. gr. 1.10 and 2 to 6 h of soaking.

• The Plant Pathology Journal
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• 제35권5호
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• pp.425-436
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• 2019

Botrytis cinerea, a major phytopathogenic fungus, has been reported to infect more than 200 crop species worldwide, and it causes massive losses in yield. The aim of this study was to evaluate the inhibitory abilities and effects of Bacillus amyloliquefaciens RS-25, Bacillus licheniformis MG-4, Bacillus subtilis Z-14, and Bacillus subtilis Pnf-4 and their culture filtrates and extracts against the gray mold caused by B. cinerea on postharvest tomato, strawberry, and grapefruit. The results revealed that the cells of Z-14, culture filtrate of RS-25, and cells of Z-14 showed the strongest biocontrol activity against the gray mold on the strawberry, grape, and tomato fruit, respectively. All the strains produced volatile organic compounds (VOCs), and the VOCs of Pnf-4 displayed the highest inhibition values. Based on headspace solid-phase microextraction in combination with gas chromatography-mass spectrometry, esters accounted for the largest percentage of the VOCs produced by RS-25, MG-4, Z-14, and Pnf-4 (36.80%, 29.58%, 30.78%, and 36.26%, respectively). All the strains showed potent cellulase and protease activities, but no chitinase activity. RS-25, Z-14, and MG-4, but not Pnf-4, grew on chrome azurol S agar, and an orange halo was formed around the colonies. All the strains showed biofilm formation, fruit colonization, and lipopeptide production, which may be the main modes of action of the antagonists against B. cinerea on the fruit. This study provides the basis for developing natural biocontrol agents against the gray mold caused by B. cinerea on postharvest fruit.