• Natural Product Sciences
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• v.23 no.4
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• pp.247-252
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• 2017

The methylglyoxal (MGO) trapping constituents from onion (Allium cepa L.) peels were investigated using pre-column incubation of MGO and crude extract followed by HPLC analysis. The peak areas of MGO trapping compounds decreased, and their chemical structures were identified by HPLC-ESI/MS. Among major constituents in outer scale of onion, 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone (2) was more effective MGO scavenger than quercetin (6) and its 4'-glucoside, spiraeoside (3). After 1 h incubation, compound 2 trapped over 90% MGO at a concentration of 0.5 mM under physiological conditions, but compounds 3 and 6 scavenged 45%, 16% MGO, respectively. HPLC-ESI/MS showed that compound 2 trapped two molecules of MGO to form a di-MGO adduct and compounds 3 and 6 captured one molecule of MGO to form mono-MGO adducts, and the positions 6 and 8 of the A ring of flavonoids were major active sites for trapping MGO.

• Journal of Applied Biological Chemistry
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• v.43 no.2
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• pp.86-93
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• 2000

An experiment was conducted to obtain the quantitative data on the transformation and loss of applied urea-N in waterlogged soil columns. The soil columns were pre-incubated for 35 days to develop oxidized and reduced soil conditions prior to urea application. After urea application at the rate of $150kg\;N\;ha^{-1}$(29.5 mg N), the amounts of nitrogen which were volatilized, leached, and remained in soil column were measured during 38 days of incubation period. On 2 and 4 days of incubation, 54.1%(15.9 mg N) and 98.4%(29.0mg N) of the applied urea was hydrolyzed, respectively. Most of the applied urea was completely hydrolyzed within 6 days. After urea application, the rates of ammonia volatilization were increased with the floodwater pH when the floodwater pH were higher than 7.0. The maximum rate of ammonia volatilization was $0.3mg\;d^{-1}$ when pH of the floodwater showed maximum value of 7.6. The total amount of volatilized nitrogen was 6.1% (1.8mg N) of the applied urea-N. A 63.2 % (18.6mg N) of the applied urea was remained in soil as $NH_4{^+}-N$ and 28.0% (8.2mg N) of the applied urea was leached as $NH_4{^+}-N$ at the end of the incubation. Amount of $NO_3{^-}-N$ in soil was smaller than 2.0 mg throughout the incubation period. The total amount of $NO_3{^-}-N$ leached was very small, which value was 1.8 mg. It suggested that nitrification process was not significant in waterlogged soil column of this study due to high infiltration rate of urea solution applied to the soil column. Therefore only small amount of $NO_3{^-}-N$ was lost by denitrification and leaching process.

• Korean Journal of Veterinary Service
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• v.39 no.3
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• pp.167-174
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• 2016

In this study, we analyzed for the changes of low organic compounds during 4 weeks incubation though inoculation of harmful microorganisms on commercial feed. Two percent of overnight cultures of Exiguobacterium acetylicum, Acinetobacter calcoaceticus, Aspergillus flavus and Fusarium graminearum were inoculated in feed, respectively. After adjusting moisture level to 50% for the promotion of feed spoilage, pH was decreased to 4.58~5.03 and microorganism was ranged to $6{\sim}10log_{10}CFU/g$. The compounds were compare between aflatoxin G1 producing feeds and aflatoxin G1 non-producing feeds. Aflatoxins G1 were detected by the immunoaffinity column clean-up method with HPLC-FLD, and were confirmed in samples incoulated by Aspergillus flavus and Acinetobacter calcoaceticus. Koiganal II, cyclohexanol and butadien-one were detected from samples (the non-sterilized inoculated feed) by Aspergillus flavus and Acinetobacter calcoaceticus. Respectively as aflatoxin G1 pre-detected substance, Koiganal II, cyclohexanol and butadien-one may be useful substance for the pre-detection of aflatoxin G1.

• Journal of the Korean Society of Tobacco Science
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• v.37 no.1
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• pp.18-24
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• 2015

Urinary mutagenicity is widely recognized as a useful biomarker for the assessment of mutagen exposure level in human. In this study, we optimized the several parameters affecting the activity of Urinary mutagenicity using highly sensitive mutation test(microsuspension assay) instead of the conventional Ames test. First of all, we chose YG1024 as a highly sensitive strain from three str ains of Salmonella typhimurium(TA98, TA100, YG1024) using r epr esentative mutation substances, such as Benzo[a]pyrene, 2-Aminonaphthalene, 2-amino-3-methyl-9H-pyrido[2,3-b]indole($MeA{\alpha}C$) and cigarette total particulate matter(TPM). And we established the several kinds of test conditions such as number of bacter ia, concentr ation of metabolic activation system and incubation time for the most sensitive reaction. Also, we optimized efficient pre-treatment method using commercial C18 column. As a r esults, this method was shown a aver age of 94 % recovery value and 13 % relative standard deviation. When we compared the Urinary mutagenicity between several participants, we confirmed that compar ative measurements were possible for different levels of urine mutagenicity. In conclusion, the optimized highly sensitive mutation test to measure the Urinary mutagenicity may be useful in biological monitoring of mutagen exposure level.

• Applied Biological Chemistry
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• v.40 no.5
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• pp.375-379
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• 1997

Two ribosome-inactivating proteins, PRIP 1 and PRIP 2 have been isolated from the leaves of $Cucurbita\;moschata\;D_{UCHESNE}$. Crude extracts were purified through ammonium sulfate precipitation and column chromatography using DE-52 cellulose, S-Sepharose, FPLC Suprose 12 HR and FPLC Mono-S. The molecular weights of PRIP 1 and PRIP 2 were 31,000 and 30,500, respectively. PRIP 2 was thermostabe and maintained its activity even after the incubation of the protein at $50^{\circ}C$ for 30 min. In a cell free in vitro translation system using rabbit reticulocyte lysate, protein synthesis was inhibited by the addition of PRIP 1 and PRIP 2. The $IC_{50}$ of PRIP 1 and PRIP 2 were 0.82 nM and 0.79 nM, respectively. The comparison of N-terminal amino acid sequences of the PRIP 1 and PRIP 2 with known RIPs revealed that PRIP 1 shows sequence similarity with Luffin B from Luffa cylindrica and Trichokirin from Trichosanthes kirilowii Maximowicz and PRH) 2 has sequence similarity with Momordin II and MAP 30 from Momordica charantia.