• Journal of Microbiology and Biotechnology
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• v.3 no.1
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• pp.24-30
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• 1993

In order to develop a novel yeast which produces the charateristic aroma of soy sauce, a protoplast fusion between Zygosaccharomyces rouxii WFS4 and Torulopsis versatilis IAM 4993 was carried out. Auxotrophic mutants as selective markers were obtained from Zygosaccharomyces rouxii and Torulopsis versatilis by treatment of N-methyl-N -nitro-N-nitrosoguanidine. The conditions of the protoplast formation and the regeneration for fusion were examined. The protoplast fusion using polyethylene glycol 4000 led to the fusion frequency of $4~5{\times}10^{-7}\;cells/ml$. Among fusants, a fusant ST723-F31 presented the best results in terms of the aromaticity of fragrance, the growth pattern, the resistance against salt and the degree of growth according to pH. It makes easy to control the production and the balance of aroma components so that it gives a good flavor, shortens the fermentation period and, simplifies the preparation process when using a bioreactor into which fusant is immobilized.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.556-557
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• 2001

This study was performed to improve the efficency of production of biosudactant which were produced by newly screened MNNGCN-Methyl-N-Nitro- Nitrosoguanidine) mutagenized P. aeruginosa EMS1. A culture grown exponentially for $30^{\circ}C$ in trypic soy brotb is adjusted to pH. MNNG is added and incubated in water bath shaker at about 250 ${\sim}$300rpm. After 20 min, is dilutecl into colded trypic soy broth and centrifugation. The cell pellet is resuspended in 50$m{\ell}$ of trypic soy broth. Cultures are grown at $30^{\circ}C$ overnight. cetyltrimethylammonium bromide-metbylene blue agar plate selected dark blue halo colony. Peanut oil, Castor oil, Olive oil, and so on were compared as carbon source of surface tension and emulsifying activity.

• Microbiology and Biotechnology Letters
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• v.13 no.1
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• pp.79-85
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• 1985

Rhizobium japonicum wild type strains isolated from local soybean variety Jangback root nodules with higher nitrogenase activity than R. japonicum 3I1110 or 61A76 was mutangenized by N-methyl-N'-nitro-N-nitrosoguanidine and UV-irradiation, and screened by effectiveness assay with soybean. One mutant strain JB65 nodulated the roots earlier than the wild type and also expressed higher acetylene-reducing activity in the presence and absence of fixed nitrogen. The selected mutant was compared with SM35 strain and showed greater nodulation and symbiotic nitrogen fixing activity with local soybean variety Jangback than SM35 strain.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.2
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• pp.316-321
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• 2000

This study carried out to eluciate the cancer chemoprevention of Korean native fermented food, baechu kimchi using Comet assay (in other words, single cell microgel electrophoresis). For this purpose, baechu kimchi was fractionated by water, n-hexane, chloroform and ethyl acetate. 5 strains of dominant fermented bacteria were isolated from baechu kimchi. The water fraction, n-hexane fraction, chloroform fraction, ethyl acetate fraction and water insoluble fractions showed no antigenotoxicitie in non-tumoral normal 3T3 cells. Among 5 bacteria isolates from baechu kimchi, two isolates bacteria 1 and 2 strongly inhibited genotoxicity of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in non-tumoral normal 3T3 cells (p<0.05). Bacteria 3, 4 and 5 were also not antigenotoxic.

• Environmental Mutagens and Carcinogens
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• v.10 no.1
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• pp.1-10
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• 1990

The regulation of DNA repair genes expression was investigated using fused genes, in which the promoter of repair genes was hybridized with the lacZ structural gene. The activities of beta-galactosidase expressed from the fused gense were highly increased when the host cells were exposed to methylating agents, such as methyl methansulfonate (MMS), N-methyl-N'-nitro-nitrosoguanidine (MNNG) and methyl nitrosourea (MNU). On the other hand, the enzyme activities from the fused genes were not induced when the cells were treated with ethylating or nonalkylating agents, such as ethyl methansulfonate (EMS), 4-nitroquinoline-1-oxide (4NQO), Bleomycin, and Benzo(a)pyrene (BP).

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.2
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• pp.149-153
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• 1992

The antimutagenic effect of green-ye1low vegetables on the mutagenicities induced by N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) and N-nitrosodimethylamine (NDMA) in Salmonella assay system and also their inhibitory effect on AZ-521 human gastric cancer cells were studied. Twenty-four items from twenty six kinds of vegetables(92%) revealed antimutagenic activity toward MNNG (p< 0.0l, 0.05). Perilla leaf, Korean cabbage, cauliflower, lettuce, mustard leaf, water dropwort, small water dropwort, carrot and burdock inhibited the mutagenicity more than 80%. The methanol extracts of the vegetables also showed the antimutagenic activity toward NDMA (p< 0.01, 0.05). Especially, perilla leaf, kale, soybean sprout and onion inhibited more than 80% of the NDMA induced mutagenicity in S. typhimurium TA100. Small water dropwort and perilla leaf exhibited the strong inhibitory effect (97~100%) on the growth of the AZ-521 human gastric cancer cells. Soybean sprout, water dropwort, broccoli, crown daisy, green red pepper, red pepper leaves, spinach, cabbage and sweet potato also inhibited growth of the cancer cells (p < 0.001~0.05).

• Korean Journal of Pharmacognosy
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• v.28 no.2
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• pp.80-83
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• 1997

The methanol extract of aerial part of Angelica keiskei Koidzumi exhibited a strong antimutagenic activity against aflatoxin $B_1\;(AFB_1)$. N-methyl-N'-nitro-N-nitrosoguanidine and 4-nitroquinoline-1-oxide in the Ames test with Salmonella typhimurium TA100. Cynaroside, isolated front ethylacetate fraction of the methanol extract Over silica gel, inhibited the mutagenicity of $AFB_1$ with an inhibition value of 96% at 1.0 mg/plate concentration and 87% at 0.5 mg/plate concentration. Other compounds, hyperoside, sucrose and luteolin-7-rutinoside, isolated from ethylactate or n-butanol fraction, also showed antimutagenic effect.

• Korean Journal of Food Science and Technology
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• v.4 no.2
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• pp.123-133
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• 1972

Over 90 of lysine producing auxotrophs were obtained from Corynebacterium sp. S-27-12, Brevibacterium flavum ATCC 15168 and Micrococcus glutamicus ATCC 13032 by UV light, $Co^{60}$ irradiation and N-methyl-N'-nitro-N-nitrosoguanidine treatment. One of the mutant, Brev. flavum U46-N59, was identified as a leucine auxotroph and accumulated lysine during flask (500 ml) cultivation (180 strokes/min.) up to 21.6 mg per ml of broth at pH 7.5 and $28^{\circ}C$ after 4 days. The medium consisted of glucose, 100; urea, 10; corn steep liquor, 40; $KH_2PO_4,\;2;\;K_2HPO_4,\;0.5;\; MgSO_4.\;7H_2O,\;0.4;\;antifoam\;S-57,\;1g;\;Fe_2(SO_4)_3.XH-2O,\;10;\; MnCl_2,\;4H_2O,\;10mg;\;biotin,\;30;\;thiamine-HCl,\;100{\mu}g$in 1l of distilled water, and 40 U/ml of penicillin was added after 36 hrs fermentation.

• Journal of the East Asian Society of Dietary Life
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• v.14 no.3
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• pp.288-293
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• 2004

This study was carried out to determine the antimutagenic and anticancer effects of fermented soybean using Ames test and cytotoxicity, respectively. The ethyl acetate fraction (200 g/plate) of fermented soybean in the Salmonella typhimurium TA100 strain showed 86.6% of inhibition rate against the mutagenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine(MNNG). In addition, the suppression of ethyl acetate fraction with same concentration of fermented soybean in the Salmonella typhimurium TA98 and TAI00 strains showed 82.4% and 90.8% inhibition against 3-amino-l,4-dimethyl-5H-pyrido-(4,3-b)indol (Trp-P-l), respectively. The cytotoxicity effects of fermented soybean against the cell lines with human lung carcinoma (A549), human gastric carcinoma (AGS) and human breast adenocarcinoma (MCF-7) were inhibited with the increase of the extract concentration. The treatment of 1.0 mg/mL ethyl acetate fraction of fermented soybean showed strong cytotoxicities of 71.6%, 91.5% and 80.7% against A549, AGS and MCF-7, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.6
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• pp.916-921
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• 1994

The inhibitory effects of the juice and boiling water extract of Houttuyina cordata Thunb., which has been known as a traditional folk antitumor agent, on the genotxicity induced by mutagens were investigated . For this purpose, Salmonella typhimurium TA98 and TA100, and the transheterozygous (mwh/+) third larvae of Drosophila melanogaster were used. The juice of fresh H. cordata 9JHC) and boiling H. cordata extract (BHC) showed antimutagenicities toared alfatoxin B₁ in S. typhimurium TA 98 and TA100. The JHC's inhibitory effect increased by 76% to 98% as the adding concentrations increased, and the BHC had a 86-97% inhibitory effect. however, in the case of N-methyl-N'-nitro-N nitrosoguanidine (MNNG), the JHC's inhibitory effect was 52-60% irrespectively of its concentrations and the BHC had a low inhibitory effect. The JHC and BHC slightly reduced the somatic chromosomal mutagenicity by MNNG in the wing hair spot test system (mwh/+) of D. melanogaster, which suggests that they can inhibit gene mutation , deletion and mitotic chromosomal recomgination.