• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1993년도 제2회 신약개발 연구발표회 초록집
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• pp.143-143
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• 1993

현재 시판되고 있는 정장용 생균 제제에 함유되어있는 정장 균주의 하나인 Bifidobacterium bifidum은 항결핵제 중 rifampicin에 감수성으로 rifampicin과 병용 투여시 본래의 정장 효과를 기대할 수없다. 따라서, rifampicin에 내성인 돌연변이 균주를 얻기 위해 B. bifidum을 N-methyl-N'-nitro-N-nitrosoguanidine(MNNG)로 처리하여 rifampicin에 내성인 30 종의 균주를 선별하였고, rifampicin에 대한 Minimal Inhibitory Concentration (MIC)를 측정해 본 결과 내성이 1,000 배 이상 상승하였다. 균주 동정을 위하여 fructose-6-phosphate phosphoketolase test를 실시해 본 결과 Bifidobacterium임이 확인되었다. 이들 내성 균주들의 유기산 생산량을 측정하여 그 생산량이 모균주와 가장 유사한 3 종의 균주를 선발하였다. 이들에 대하여 Escherichia coli 생육 억제능을 시험해 본 결과 E. coil 생육 억제능이 모균주와 유사하였다. 또, rifampicin을 함유한 배지에서 돌연변이 균주를 배양시킨 경우 rifampicin이 안정한 상태로 잔존한 것을 알 수 있었다. 이것으로 보아 돌연변이 균주들은 rifampicin을 분해 또는 변형시키는 효소를 생산하지 않는다고 볼 수 있다. 이상의 결과로 본 연구에서 개발한 돌연변이 균주들, 즉 B. bifidum RFRll, RFR21 그리고 RFR61은 rifampicin에 내성이면서 모균주와 동일한 생화학적 특성을 갖는 정장 균주로 여겨진다.

• 한국식품위생안전성학회지
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• 제10권4호
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• pp.219-224
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• 1995

The antimutagenic effects of 46 kinds of medicinal plants that have been used as traditional folk antitumor agents in Korea were studied by using Ames mutagenicity test. Most of the methanolic extracts from the plants which were used in this experiment showed strong antimutagenic activity toward aflatoxin B1(AFB1) in Salmonella typhimrium TA100 and TA98. However, N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) induced mutagenicity was not blocked by adding the methanolic extracts of the plants except persimmon leaves (Diospyros kaki Thunberg)and Elaeagnus umbellata.

• Journal of Microbiology and Biotechnology
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• 제2권2호
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• pp.102-107
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• 1992

For the purpose of producing L-ornithine by microbial fermentation, mutant strains were developed from glutamate-producing bacteria by mutagenesis using N-methyl-N'-nitro-N-nitrosoguanidine (NTG) and UV irradiation. Brevibacterium ketoglutamicum BK1046, a L-citrulline auxotroph which is also resistant to arginine hydroxamate (Arghx), was isolated and selected as the best producer of L-ornithine. This strain was capable of producing L-ornithine at a concentration of 24 g/l after 69 hours of cultivation in the 21 jar fermentor. The optimum supplementary level of L-arginine, a substitute for L-citrulline, was found to be about 0.2 g/l in the shake-flask fermentation.

• 약학회지
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• 제32권6호
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• pp.394-401
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• 1988

Lactobacillus casei was treated with N-methyl-N'-nitro-N-nitrosoguanidine(NTG) to obtain resistant mutants to rifampicin. Freshly grown cells of the strain suspended in tris-maleic acid buffer were exposed to NTG of $50{\mu}g/ml$ for 30min. Five colonies of the NTG-induced mutants showed distinct resistance to rifampicin. They also exhibited identical characteristics with the original Lactobacillus casei when they were tested for growth, titrable acidity and sugar fermentation. It is suggested that they can be utilized as efficieient starter cultures for fermented milk.

• 한국식품영양과학회지
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• 제27권1호
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• pp.157-162
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• 1998

The antimutagenic activity of three kinds of extract such as fresh juice, ethanol extract and water extract of Artemisia iwayomogi against 3 - amino - 1, 4 - dimethyl - 5H - pyrido [4,3-b] indol (Trp-P-1) and N - methyl - N' - nitro - N -nitrosoguanidine(MNNG) was demonstrated with the Salmonella typhimurium assay. The number of revertants per plate decreased significantly when these extracts(0.5ug/plate) added to the assay system system using S. typhimurium TA 100. These extracts also showed prominant cytotoxic activity against four different kinds of human cancer cell as human lung cancer cell (A549), breast cancer cell(MCF7), fibrosacoma cell(HT1080) and gastric cancer cell(KATOIII), respectively.

• Journal of Plant Biology
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• 제36권1호
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• pp.105-112
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• 1993

Selection of glyphosate-resistant clones from MNNG-treated mesophyll protoplasts of haploid tobacco and their differentiation were studied. The protoplasts were treated with 0.1 to 100 $\mu\textrm{g}$/mL N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) for 30 min when they expanded to oval shapes. After the treatment, the protoplasts in 4-16 cell stages were transferred to the selective medium containing 1 mM glyphosate for the selection of the glyphosate-resistant colonies. The efficiency of the cell division of the protoplasts in the selective medium decreased as the MNNG concentrations in creased. Optimal MNNG concentration for induction of the glyphosate-resistant clones was 10$\mu\textrm{g}$/mL and mutation frequency was 2.66$\times$10-6. The stability of the glypohsate-resistance of the clones was examined by prolonged subculture in the medium with 1 mM glyphosate, and the resistant clones were survived more than 10 months. Among them one clone has been proliferating and greening and the others were proliferating without greening or greening with slower proliferating.

• Mycobiology
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• 제37권4호
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• pp.267-271
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• 2009

A fungal strain producing a high level of cellulase was selected from 320 fungal isolates and identified as Aspergillus sp. This strain was further improved for cellulase production by sequential treatments by two repeated rounds of $\gamma$-irradiation of $Co^{60}$, ultraviolet treatment and four repeated rounds of treatment with N-methyl-N'-nitro-N-nitrosoguanidine. The best mutant strain, Aspergillus sp. XTG-4, was selected after screening and the activities of carboxymethyl cellulase, filter paper cellulase and $\beta$-glucosidase of the cellulase were improved by 2.03-, 3.20-, and 1.80-fold, respectively, when compared to the wild type strain. After being subcultured 19 times, the enzyme production of the mutant Aspergillus sp. XTG-4s was stable.

• 한국미생물·생명공학회지
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• 제19권5호
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• pp.536-541
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• 1991

유당발효 효모인 Kluyveromyces lactis ATCC 8585를 이용하여 유청에서 과일향 풍미성분의 생산성을 향상시키기 위하여 3차에 걸처 NTG를 처리하고 geraniol의 항균력에 내성을 지니는 변이주 중 모균주에 비해 yeasty-flavor는 약하나 fruity-flavor가 강한 변이주를 선발하고 K.lactis 450 K라 명명하였다. 3일간 배양시킨 발효액을 pentane-dichloromethane(2:1)용매로 추출하여 얻은 oleoresin을 gas chromatography로 분석한 결과, 모균주보다 변이주가 더 많은 종류와 양의 향기성분을 생산한 것으로 나타났다.

• 한국미생물·생명공학회지
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• 제27권1호
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• pp.15-22
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• 1999

Various lactic acid bacteria were isolated from Korean Kimchi in order to study their antimutagenic substances. Ames test using Salmonella typhimurium TA98 and TA100 showed the strain KLAB21 to have the highest antimutagenic activity among the 230 isolated strains against MNNG (N-methyl-N'-nitro-N-nitrosoguanidine), NPD (4-nitro-O-phenylenediamine), NQO (4-nitrosoquinoline-1-oxide) and AFB1 (aflatoxin B1). The strain was identified as Lactobacillus plantarum based on its morphological, cultural and physiological characteristics. Antimutagenic activity of L. plantarum KLAB21 was found in culture supernatant suggesting the bacterium secrete antimutagenic substance in the media. No mutagenic activity was found in the culture supernatant. The isolated strain L. plantarum KLAB21 showed much higher antimutagenic activity than L. plantarum IAM1261 which is being used industrially for fermented milk production. The antimutagenic activity of L.plantarum KLAB21 was reconfirmed by the spore-rec assay using spores of Bacillus subtilis H17($Rec^+$) and M45($Rec^-$).

• 한국식품영양과학회지
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• 제24권3호
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• pp.440-445
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• 1995

The antimutagenic effects of juices from green pepper(GP), red pepper leaf(RPL), red pepper(RP) and sweet pepper(SP) were examined by the Ames method using Salmonella typhimurium TA100. The juice supernatants of GP, RPL and RP showed antimutagenic activities against afltoxin B1(AFB1) in Salmonella typhimurium TA 100. The juice supermatants of GP and RPL also exhibited the inhibitory effects(p<0.05) to the mutagenicities induced by N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) and 4-nitro-quinoline-1-oxide(4-NQO). The juice of RP showed antimutagenic activities against indirect mutagen of AFB1, however, the activity was reduced at higher concentration(5.0%), furthermore, as the adding concentration of sample increased to 5.0%, it exhibited slight comutagenicith on direct mutagen of MNNG. Theantimutagenic activities of GP and RPL juices were reduced significantly after heating at 100℃ for 20min, supposing that the antimutagenic compound(s) in the juices were heat labile.