• 미생물학회지
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• 제33권3호
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• pp.199-202
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• 1997

방선균(Streptomyces) 포자와 효모(Saccharomyces) 반수체 및 배수체 세포를 대상으로 전기충격(AC 38V/1.3 cm)이 화학적 돌연변이원인 N-methyl-N'-nitro-N-nitrosoguanidine(NTG)의 세포치사효과와 돌연변이 유발에 미치는 영향을 조사하였다. 방선균의 경우 전기충격 단독 처리로는 180분 처리하였을 때 생존율이 100%이었으나 960분 처리한 경우에는 모두 사멸하였다. 전기충격과 NTG처리를 병행한 바 방성균의 경우 180분 처리시, NTG 단독 처리시보다 생존율이 72%에서 48%로 감소되었고, 반수체 효모의 경우 40분 처리시 8%에서 3%로, 배수체 효모의 경우 25%에서 10%로 각각 감소되었다. 전기충격과 NTG에 의한 영양요구 돌연변이 형성율에 있어서는 전기충격이 NTG에 의한 돌연변이율을 120분 처리 후 1.8%에서, 13.6%로, 반수체효모의 경우 40분 처리후 2.4%에서 4.8%로 각각 증가시켰다.

• 미생물학회지
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• 제27권2호
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• pp.155-161
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• 1989

Lactobacillus sporogenes를 NTG로 처리하여 rifampicin에 내성인 돌연변이 균주를 얻었으며, 이중 58 종이 rifampicin에 현저한 내성을 보였다. 9종의 mutants를 선발하여 그 생화학적 특성을 검토한 결과, 포자형성능, 산생성능, E. coli 생육억제능 면엣 parent와 유사한 특성을 나타내었다. In vitro 시험을 통해ㅐ, 내성균주들에 의해 rifampicin이 불활성화 되지 않음이 밝혀졌다. 따라서 이들 mutants를 유산균 제제원으로 사용할 수 있으며, 그 제제는 rifampicin과 병용투여시, 효과적인 정장제로 사용될 수 있을 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제8권2호
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• pp.119-123
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• 1998

The feasibility of using combined treatments of electric field and chemical mutagen N-methyl-N'-nitro-N-nitroso-guanidine (NTG) for the strain improvement of Saccharomyces sp. in ethanol production was examined. The treatment of electric field alone resulted in no effect on the lethality of yeast cells under the conditions of this study. However, when the electric field was applied together to the treatment of yeast cells with NTG, the electric field increased the lethal effect and auxotrophic mutation rate of NTG. The combined treatment of electric field and NTG also increased the chances of. obtaining superior yeast strains for the ethanol production from tapioca. A higher number of improved clones was obtained by the combined treatments of electric field and NTG than by the NTG treatment alone. The best clone, NF 30-9, which was also obtained by the combined treatment, produced $11.07\%$ (w/v) ethanol from tapioca slurry containing 25% (w/v) reducing sugar while the parental strain produced 9.77% (w/v).

• Journal of Microbiology and Biotechnology
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• 제14권3호
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• pp.570-575
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• 2004

Three different strains of carotenoid accumulating XantlwphyUomyces dendrorhous mutants, JH1, JH2, and JH3, were isolated by NTG (N-methyl-N'-nitro-N-nitrosoguanidine) mutagenesis, which might potentially be useful for animal feed as well as for studies on the regulation and biosynthesis of astaxanthin. Mutants were selected based on the capability of growth and carotenoid production on the YM agar plate containing chemical inhibitor, $\beta$-ionone. Astaxanthin-overproducing mutant JH1 produced 4.032 mg astaxanthinlg dry cell weight, and this value was about 15-folds higher than that of wild-type. $\beta$-Carotene-overproducing mutant JH2 produced 0.273 mg $\beta$-carotene/g dry cell weight, and this was 4-folds increase from that of wild-type. In contrast, JH3 was a white-colored mutant that was unable to produce carotenoid pigment.

• 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.

• 자연과학논문집
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• 제8권1호
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• pp.33-39
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• 1995

Klebsiella sp. L-10을 N-methyl-N'-nitro-N''-nitrosoguanidine 과 ethylmethane sulfornate 및 자외선 등으로 돌연변이시켜 히아루론산 복합체의 수율이 친주보다 약 2.5배 증대된 NTG 50 변이주를 얻었다. NTG 50변이주를 이용한 히아루론산 복합체의 최적 생산배지 조성은 효모 추출물 0.1%, 트립톤 3%, 포도당 3%, $K_2HPO_4$ 와 $KH_2PO_4$ 각각 30nM 이었고 배양조건은 배지의 초기 pH 6.0-6.5, 배양온도 $37^{\circ}C$, 24시간의 진탕배양이었으며 이때 배양액 리터당 2900mg의 히아루론산 복합체가 생산되었다.

• 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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• 제19권2호
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• pp.122-127
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• 1991

A bacterial strain NO. 32 which produced thermostable ${\alpha}$-amylase was isolated from soil and identified to genus of Bacillus. To enhance ${\alpha}$-amylase productivity, a successive mutation of Bacillus sp. No. 32 was attempted with treatment of N-methyl-N'-nitro-N-nitrosoguanidine (NTG). The resulting mutant, Bacillus sp. No. 32H417, which is risistant to refampicin and deficient in spore formation, produced about 90-fold high level of ${\alpha}$-amylase when compared with parental strain. The properties of the enzyme for thermostability were investigated. The optimal temperature and pH for enzyme reaction were 95$^{\circ}C$ and pH6.5, respectively, in the presence of 0.3mM $Ca^{2+}$ as an effective stabilizer.

• 한국미생물·생명공학회지
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• 제19권6호
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• pp.583-587
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• 1991

대장균 W3110으로부터 NTG 및 UV를 사용하여 여러 단계의 돌연변이 실험을 거치면서 스레오닌 고생산균주인 대장균 TF427를 선별하였다. 선별된 변이주는 스레오닌 유사체인 AHV 내성, 메치오닌 및 이소루이신 요구성을 특징으로 한다. 5-L 발효조 실험에서 44시간 발효하였을 때 46.5g/l의 스레오닌이 생산되었다. 효모분석에 의하면, TF427의 아스파토키나아제 I의 활성은 스레오닌에 의해 저해받지 않았으며, 이 효소의 합성은 스레오닌과 이소루이신에 의해 억제를 받지 않았다.

• KSBB Journal
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• 제14권3호
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• pp.351-357
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• 1999

A marine bacterium Bacillus cereus ASK202, agarase producing strain, was treated with some mutagenic agents, ultraviolte(UV), 1-methyl-3-nitro-1-nitrosoguanidine(NTG), and ethyl methane sulfonate(EMS), several times for the increasing of the agarase production After mutagen treatment, we isolated one mutant strain treated with NTG showed the highest stability and agarase productivity and named as Bacillus cereus ASK202-N3. This Bacillus cereus ASK202-N3 strain was well grown in the modified marine medium containing 0.5%(w/v) agar, 0.3%(w/v) yeast extract, and 5.0%(w/v) NaCl, and the optimal initial pH, temperature and culture time were 7.8, $25^{\circ}C$ and 32h, respectively. In the optimal culture conditions, the agarase production was increased to 5.3 fold(850units/L) compared to that of the wild type.