• Title/Summary/Keyword: Reverse mutation

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Genotoxicity Study of Sophoricoside, a Constituent of Sophora japonica, in Bacterial and Mammalian Cell System

  • Kim, Youn-Jung;Park, Hyo-Joung;Kim, Young-Soo;Kim, Mi-Kyung;Lee, Seung-Ho;Jung, Sang-Hun;Ryu, Jae-Chun
    • Environmental Mutagens and Carcinogens
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    • v.21 no.2
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    • pp.99-105
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    • 2001
  • Sophoricoside was isolated as the inhibitor of IL-5 bioactivity from Sophora japonica (Leguminosae). It has been reported to has an anti-inflammatory effect on rat paw edema model. To develope as an anti-allergic drug, genotoxicity of sophoricoside was investigated in bacterial and mammalian cell system such as Ames bacterial reversion test, chromosomal aberration assay and single cell gel electrophoresis (Comet) assay. As results, in the range of 1,250~40 $\mu\textrm{g}$/plate sophoricoside concentrations was not shown significant mutagenic effects in Salmonella typhimurium TA 98, TA 100, TA 1535 and TA 1537 strains in Ames test. The 80% cell growth inhibition concentration (IC/SUB 80/) of sophoricoside was determined as above 5,000 $\mu\textrm{g}$/$m\ell$ in Chinese hamster lung (CHL) fibroblast cell and L5178Y mouse lymphoma cell line for the chromosomal aberration and comet assay, respectively. Sophoricoside was not induced chromosomal aberration in CHL fibroblast cell at concentrations of 700, 350 and 175 $\mu\textrm{g}$/$m\ell$ or 600, 300 and 150 $\mu\textrm{g}$/$m\ell$ in the absence or presence of S-9 metabolic activation system, respectively. Also, in the comet assay, the induction of DNA damage was not observed in L5178Y mouse lymphoma cell line both in the absence or presence of S-9 metabolic activation system. From these results, no genotoxic effects of sophoricoside were observed in bacterial and mammalian cell systems used in these experiments.

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Mutagenecity Test of Intralipidos (Intralipidos에 대한 변이원성시험)

  • Jung, Ji-Youn;Lee, Won-Woo;Ihm, Jong-Hee;Nam, Jeong-Seok;Che, Jeong-Hwan;Li, Guang-Xun;Kang, Byeong-Cheol;Yi, Beoung-Hi;Park, Jae-Hak;Lee, Yong-Soon
    • Toxicological Research
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    • v.14 no.3
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    • pp.453-457
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    • 1998
  • In order to evaluate the mutagenic potential of Intralipidos produced by Greenmate cooperation. We performed Salmonella typhimurium reversion assay, chromosomal aberration test on chinese hamster ovarian cells and in vivo micronucleus assay using mouse bone marrow cells. In the reverse mutation test using Salmonella typhimurium TA98 and TA100, Intralipidos did not increase the number of revertant at any of the concentration tested in this study. Intralipidos did not increase the number of cells having structural or numberical chromosome aberration in cytogenetic test. In mouse micronucleus test, no significant increase were observed in the occurrence of micornucleated polychromatic erythrocytes in ICR male mice intraperitoneally administered with Intralipidos. These results indicate that Intralipidos has no genetic toxicity under these experimental conditions.

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Non-Aflatoxigenicity of Commercial Aspergillus oryzae Strains Due to Genetic Defects Compared to Aflatoxigenic Aspergillus flavus

  • Tao, Lin;Chung, Soo Hyun
    • Journal of Microbiology and Biotechnology
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    • v.24 no.8
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    • pp.1081-1087
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    • 2014
  • Aspergillus oryzae is generally recognized as safe, but it is closely related to A. flavus in morphology and genetic characteristics. In this study, we tested the aflatoxigenicity and genetic analysis of nine commercial A. oryzae strains that were used in Korean soybean fermented products. Cultural and HPLC analyses showed that none of the commercial strains produced detectable amount of aflatoxins. According to the molecular analysis of 17 genes in the aflatoxin (AF) biosynthetic pathway, the commercial strains could be classified into three groups. The group I strains contained all the 17 AF biosynthetic genes tested in this study; the group II strains deleted nine AF biosynthetic genes and possessed eight genes, including aflG, aflI, aflK, aflL, aflM, aflO, aflP, and aflQ; the group III strains only had six AF biosynthetic genes, including aflG, aflI, aflK, aflO, aflP, and aflQ. With the reverse transcription polymerase chain reaction, the group I A. oryzae strains showed no expression of aflG, aflQ and/or aflM genes, which resulted in the lack of AF-producing ability. Group II and group III strains could not produce AF owing to the deletion of more than half of the AF biosynthetic genes. In addition, the sequence data of polyketide synthase A (pksA) of group I strains of A. oryzae showed that there were three point mutations (two silent mutations and one missense mutation) compared with aflatoxigenic A. flavus used as the positive control in this study.

Expression, Purification and NMR Studies on MC4R-TM2 Mutant

  • Oh, Dae-Seok;Yun, Ji-Hye;Lee, Weon-Tae
    • Journal of the Korean Magnetic Resonance Society
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    • v.16 no.1
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    • pp.34-45
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    • 2012
  • Melanocortin-4 receptor (MC4R) subtype is associated with obese humans. Especially, in a patient with severe early-onset obesity, novel heterozygous mutation in the MC4R gene was detected, resulting in an exchange of aspartic acid to asparagine in $90^{th}$ amino acid residue located in the predicted second trans-membrane domain (TM2). Mutations in the melanocortin-4 receptor (MC4R) gene are the most frequent monogenic causes of severe obesity which have been described as heterozygous with loss of function. In order to compare structure difference between MC4R wild type (MC4R-TM2-wt) and mutant (MC4R-TM2-D90N), we designed both MC4R-TM2-wt and MC4R-TM2-D90N construct in pET 21b vector. In this study, we optimized high-yield purification procedure for recombinant TM2-D90N. Eluted recombinant protein was resolubilized under urea condition for thrombin cleavage reaction and we conducted the high-performance liquid chromatography (HPLC) with reverse phase column under 1% acetonitrile, 0.01% TFA buffer solution. The molecular size of purified target peptide was confirmed by Tricine-SDS page analysis. To characterize MC4R-TM2-D90N, we have performed $^{15}N$-isotope labeling of peptide using M9 media and purified labeled target peptide for hetero-nuclear NMR spectroscopy.

Evaluation of Genotoxicity and 28-day Oral Dose Toxicity on Freeze-dried Powder of Tenebrio molitor Larvae (Yellow Mealworm)

  • Han, So-Ri;Yun, Eun-Young;Kim, Ji-Young;Hwang, Jae Sam;Jeong, Eun Ju;Moon, Kyoung-Sik
    • Toxicological Research
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    • v.30 no.2
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    • pp.121-130
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    • 2014
  • The larval form of Tenebrio molitor (T. molitor) has been eaten in many countries and provides benefits as a new food source of protein for humans. However, no information exists regarding its safety for humans. The objective of the present study was to evaluate the genotoxicity and repeated dose oral toxicity of the freeze-dried powder of T. molitor larvae. The genotoxic potential was evaluated by a standard battery testing: bacterial reverse mutation test, in vitro chromosome aberration test, and in vivo micronucleus test. To assess the repeated dose toxicity, the powder was administered once daily by oral gavage to Sprague-Dawley (SD) rats at dose levels of 0, 300, 1000 and 3000 mg/kg/day for 28 days. The parameters which were applied to the study were mortality, clinical signs, body and organ weights, food consumption, ophthalmology, urinalysis, hematology, serum chemistry, gross findings and histopathologic examination. The freezedried powder of T. molitor larvae was not mutagenic or clastogenic based on results of in vitro and in vivo genotoxicity assays. Furthermore, no treatment-related changes or findings were observed in any parameters in rats after 28 days oral administration. In conclusion, the freeze-dried powder of T. molitor larvae was considered to be non-genotoxic and the NOAEL (No Observed Adverse Effect Level) was determined to be 3000 mg/kg/day in both sexes of SD rats under our experimental conditions.

Evaluation of the Genotoxicity of Decursin and Decursinol Angelate Produced by Angelica gigas Nakai

  • Kim, Kang-Min;Kim, Tae-Ho;Park, Yun-Jung;Kim, Ik-Hwan;Kang, Jae-Seon
    • Molecular & Cellular Toxicology
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    • v.5 no.1
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    • pp.83-87
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    • 2009
  • In this study, we assessed the stability and toxicological safety of Angelica gigas Nakai (A. gigas Nakai) extract, which is comprised of decursin and decursinol angelate (D/DA). D/DA was tested for mutagenicity using Ames Salmonella tester strains (TA102, TA1535, and TA1537) with or without metabolic activation (S9 mix). No increase in the number of revertants was observed in response to any of the doses tested (1.25, 12.5, 125, and $1,250{\mu}/mLg$). In addition, a chromosome aberration test was conducted in the Chinese hamster lung (CHL) cell line. To accomplish this, cells were treated with D/DA (3.28, 13.12, 52.46, and $209.84{\mu}g/mL$) or with Mitomycin C ($0.1{\mu}/mLg$) as a positive control in the case of no metabolic activation or benzo(a)pyrene ($20{\mu}g/mL$) in the case of metabolic activation. No significant increase in chromosome aberrations was observed in response to treatment with any of these concentrations, regardless of activation of the metabolic system. According to these results, we concluded that D/DA did not induce bacterial reverse mutation or clastogenicity in vitro in the range of concentrations evaluated in these experiments.

Quantitative comparison of mRNA expression of glucosyltransferase (GTF) between $xylitol-resistant(X^R)$ and $xylitol-sensitive(X^S)$ mutans streptococci (Mutans streptococci의 자일리톨 내성균주와 감성균주의 glucosyltransferase mRNA의 정량적 비교 연구)

  • Lee, MI-Na;Kim, Young-Jae;Lee, Sung-Hoon;Kim, Chong-Chul
    • Journal of the korean academy of Pediatric Dentistry
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    • v.33 no.1
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    • pp.77-84
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    • 2006
  • Since the long-term exposure of mutans streptococci to xylitol is known to select for xylitol-resistant $(X^R)$ natural mutants, the occurrence and survival of such $(X^R)$ strains were performed in batch culture methods. The aim of the study was to compare the differentiation and quantification of mRNA expression of the gtf genes of $X^R\;and\;X^S$ mutans streptococci. Using a real-time reverse-transcription polymerase chain reaction, the expression of each gtf was determined. In $X^R$ strains, the relative levels of transcription of gtfB and gtfC were decreased while that of gtfD was increased, suggesting the presence of independent promoters. It also suggested that mutation related to production of glucosyltransferase occurred under the exposure of xylitol could explain the caries-preventive mechanisms of xylitol.

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General and Genetic Toxicology of Enzyme-Treated Ginseng Extract - Toxicology of Ginseng Rh2+ -

  • Jeong, Mi-Kyung;Cho, Chong-Kwan;Yoo, Hwa-Seung
    • Journal of Pharmacopuncture
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    • v.19 no.3
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    • pp.213-224
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    • 2016
  • Objectives: Ginseng Rh2+ is enzyme-treated ginseng extract containing high amounts of converted ginsenosides, such as compound k, Rh2, Rg3, which have potent anticancer activity. We conducted general and genetic toxicity tests to evaluate the safety of ginseng Rh2+. Methods: An acute oral toxicity test was performed at a high-level dose of 4,000 mg/kg/day in Sprague-Dawley (SD) rats. A 14-day range-finding study was also conducted to set dose levels for the 90-day study. A subchronic 90-day toxicity study was performed at dose levels of 1,000 and 2,000 mg/kg/day to investigate the no-observed-adverse-effect level (NOAEL) of ginseng Rh2+ and target organs. To identify the mutagenic potential of ginseng Rh2+, we conducted a bacterial reverse mutation test (Ames test) using amino-acid-requiring strains of Salmonella typhimurium and Escherichia coli (E. coli), a chromosome aberration test with Chinese hamster lung (CHL) cells, and an in vivo micronucleus test using ICR mice bone marrow as recommended by the Korean Ministry of Food and Drug Safety. Results: According to the results of the acute oral toxicity study, the approximate lethal dose (ALD) of ginseng Rh2+ was estimated to be higher than 4,000 mg/kg. For the 90-day study, no toxicological effect of ginseng Rh2+ was observed in body-weight changes, food consumption, clinical signs, organ weights, histopathology, ophthalmology, and clinical pathology. The NOAEL of ginseng Rh2+ was established to be 2,000 mg/kg/day, and no target organ was found in this test. In addition, no evidence of mutagenicity was found either on the in vitro genotoxicity tests, including the Ames test and the chromosome aberration test, or on the in vivo in mice bone marrow micronucleus test. Conclusion: On the basis of our findings, ginseng Rh2+ is a non-toxic material with no genotoxicity. We expect that ginseng Rh2+ may be used as a novel adjuvant anticancer agent that is safe for long-term administration.

A TILLING Rice Population Induced by Gamma-ray Irradiation and its Genetic Diversity

  • Cho, Hyun Yong;Park, Seo Jung;Kim, Dong Sub;Jang, Cheol Seong
    • Korean Journal of Breeding Science
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    • v.42 no.4
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    • pp.365-373
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    • 2010
  • TILLING (Targeting Induced Local Lesions IN Genomes) is broadly regarded as an excellent methodology for reverse genetics applications. Approximately 15,000 $M_3$ TILLING lines have been developed via the application of gamma-ray irradiation to rice seeds (cv. Donganbyeo), followed by subsequent selections. In an effort to evaluate the genetic diversity of the TILLING population, we have employed the AFLP multiple dominant marker technique. A total of 96 (0.64%) TILLING lines as well as Donganbyeo were selected randomly and their genetic diversity was assessed based on AFLP marker polymorphisms using 5 primer combinations. An average of 100.4 loci in a range of 97 to 106 was detected using these primer combinations, yielding a total of 158 (31.4%) polymorphic loci between Donganbyeo and each of the 96 lines. A broad range of similarity from 80% to 96% with an average of 89.4% between Donganbyeo and each of the 96 lines was also observed, reflecting the genetic diversity of the TILLING population. Approximately 28 polymorphic loci have been cloned and their sequences were BLAST-searched against rice whole genome sequences, resulting in 20 matches to each of the gene bodies including exon, intron, 1 kb upstream and 1 kb downstream regions. Six polymorphic loci evidenced changes in the coding regions of genes as compared to the rice pseudomolecules, 4 loci of which exhibited missense mutations and 2 loci of which exhibited silent mutations. Therefore, the results of our study show that the TILLING rice population should prove to be a useful genetic material pool for functional genomics as well as mutation breeding applications.

Genotoxicity Study of ChondroT (ChondroT의 유전독성 연구)

  • Kim, Sun-Gil;Kim, Joo Il;Kim, Ji-Hoon;Yoon, Chan Suk;Jeong, Ji-Won;Na, Chang-Su;Kim, Seon-Jong
    • Journal of Korean Medicine Rehabilitation
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    • v.31 no.1
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    • pp.59-79
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    • 2021
  • Objectives This study was performed to observe the genotoxic effect of the ChondroT. Methods To evaluate the genotoxicity of ChondroT, an experiment of bacterial reverse mutation test, in vitro mammalian chromosomal aberration test and mammalian erythrocyte micronucleus test in mouse was conducted. Results TA98, TA100 and TA1537 strains in the absence of metabolic activation system (S9 mix), the number of revertant colonies being greater than 2-fold of the respective negative control value. Both in -S9 mix and +S9 mix, the frequencies of aberration cells with structural aberration and numerical aberrations of chromosome were less than 5%. There was no increase of polychromatic erythrocyte with one or more micronuclei at any dose of test substance compared to the negative control group (p<0.05). Conclusions In TA98, TA100 and TA1537 strains in the absence of metabolic activation system (S9 mix), the number of revertant colonies was greater than 2-fold of the respective negative control value, showing positive results. ChondroT was considered to be non-clastogenic to Chinese hamster lung (CHL/IU) cells under the present experimental condition. and ChondroT was determined not to induce an increased frequency of micronuclei in the bone marrow cells of male ICR mice under the present experimental condition.