• Title/Summary/Keyword: Reverse mutation

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Improved Resistance to Oxidative Stress by a Loss-of-Function Mutation in the Arabidopsis UGT71C1 Gene

  • Lim, Chae Eun;Choi, Jung Nam;Kim, In A;Lee, Shin Ae;Hwang, Yong-Sic;Lee, Choong Hwan;Lim, Jun
    • Molecules and Cells
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    • v.25 no.3
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    • pp.368-375
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    • 2008
  • Approximately 120 UDP-glycosyltransferases (UGTs), which are classified into 14 distinct groups (A to N), have been annotated in the Arabidopsis genome. UGTs catalyze the transfer of sugars to various acceptor molecules including flavonoids. Previously, UGT71C1 was shown to glycosylate the 3-OH of hydroxycinnamates and flavonoids in vitro. Such secondary metabolites are known to play important roles in plant growth and development. To help define the role of UGT71C1 in planta, we investigated its expression patterns, and isolated and characterized a loss-of-function mutation in the UGT71C1 gene (named ugt71c1-1). Our analyses by quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR), microarray data mining, and histochemical detection of GUS activity driven by the UGT71C1 promoter region, revealed the tissue-specific expression patterns of UGT71C1 with highest expression in roots. Interestingly, upon treatment with methyl viologen (MV, paraquat), ugt71c1-1 plants displayed enhanced resistance to oxidative stress, and ROS scavenging activity was higher than normal. Metabolite profiling revealed that the levels of two major glycosides of quercetin and kaempferol were reduced in ugt71c1-1 plants. In addition, when exposed to MV-induced oxidative stress, eight representative ROS response genes were expressed at lower levels in ugt71c1-1 plants, indicating that ugt71c1-1 probably has higher non-enzymatic antioxidant activity. Taken together, our results indicate that ugt71c1-1 has increased resistance to oxidative stress, suggesting that UGT71C1 plays a role in some glycosylation pathways affecting secondary metabolites such as flavonoids in response to oxidative stress.

Detection of Clarithromycin-resistant Strains from Clinical Isolates of Mycobacterium abscessus (Clarithromycin 약제에 대한 Mycobacterium abscessus 임상 내성 균주 분리)

  • Lee, Seung Heon;Park, Young Kil;Ryo, Sung Weon;Shim, Myung Sup;Lew, Woo Jin;Kim, Hee Jin
    • Tuberculosis and Respiratory Diseases
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    • v.64 no.6
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    • pp.422-426
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    • 2008
  • Background: Mycobacterium abscessus is the most pathogenic and drug-resistant rapid-growing mycobacterium. Clarithromycin or azithromycin are the only regular oral antimycobacterial agents that have an effect on M. abscessus. We tried to detect the clarithromycin-resistant strains from the clinical isolates of M. abscessus. Methods: We tried to isolate the clarithromycin-resistant strains from 220 clinical isolates of M. abscessus by performing using reverse hybridization assay (RHA) and the broth microdilution test (BMT). Results: Seven resistant strains (3.2%) from all the tested clinical isolates were detected by BMT. Three of these resistant strains were also detected by RHA and it was confirmed that they had point mutants. Conclusion: These results showed that clarithromycin resistance in M. abscessus clinical isolates is related to a point mutation and other unknown mechanisms.

Effects of carbendazim on DNA, gene and chromosome (살균제 carbendazim이 DNA, 유전자 및 염색체에 미치는 영향)

  • Lee, Je-Bong;Sung, Pil-Nam;Jeong, Mi-Hye;Shin, Jin-Sup;Kang, Kyu-Young
    • The Korean Journal of Pesticide Science
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    • v.8 no.4
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    • pp.288-298
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    • 2004
  • Benzimidazole pesticide carbendazim that is effective against a wide range of fungal plant pathogens is a protective, eradicant, and systemic fungicide. For genetic toxicity evaluation of carbendazim on DNA, genes and chromosome, were investigated with chromosome aberration, bacterial reverse mutation, micronucleus test in mouse born marrow and DNA damage assay by single cell microgel electrophoresis. Substitution and frameshift mutation were not induce at variable concentration of carbendazim on Ames test with or without rat liver microsomal activation. For the result of chromosome aberration test, numerical changes of chromosome were detected at the concentrations higher than $4.0{\mu}g/m{\ell}$, but structural aberration was not induced. Positive control, Mitomycin-C and captafol made a structural aberration, but numerical change of chromosome did not appear. In the micronucleus test for mouse born marrow, carbendazim was negative, but was weak positive in DNA damage assay by single cell microgel electrophoresis because of increased DNA moving length of 20% to control.

Association of Ultrasonography Features of Follicular Thyroid Carcinoma With Tumor Invasiveness and Prognosis Based on WHO Classification and TERT Promoter Mutation

  • Myoung Kyoung Kim;Hyunju Park;Young Lyun Oh;Jung Hee Shin;Tae Hyuk Kim;Soo Yeon Hahn
    • Korean Journal of Radiology
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    • v.25 no.1
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    • pp.103-112
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    • 2024
  • Objective: To investigate the association of ultrasound (US) features of follicular thyroid carcinoma (FTC) with tumor invasiveness and prognosis based on the World Health Organization (WHO) classification and telomerase reverse transcriptase (TERT) promoter mutations. Materials and Methods: This retrospective study included 54 surgically confirmed FTC patients with US images and TERT promoter mutations (41 females and 13 males; median age [interquartile range], 40 years [30-51 years]). The WHO classification consisted of minimally invasive (MI), encapsulated angioinvasive (EA), and widely invasive (WI) FTCs. Alternative classifications included Group 1 (MI-FTC and EA-FTC with wild type TERT), Group 2 (WI-FTC with wild type TERT), and Group 3 (EA-FTC and WI-FTC with mutant TERT). Each nodule was categorized according to the US patterns of the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) and American College of Radiology-TIRADS (ACR-TIRADS). The Jonckheere-Terpstra and Cochran-Armitage tests were used for statistical analysis. Results: Among 54 patients, 29 (53.7%) had MI-FTC, 16 (29.6%) had EA-FTC, and nine (16.7%) had WI-FTC. In both the classifications, lobulation, irregular margins, and final assessment categories showed significant differences (all Ps ≤ 0.04). Furthermore, the incidences of lobulation, irregular margin, and high suspicion category tended to increase with increasing tumor invasiveness and worse prognosis (all Ps for trend ≤ 0.006). In the WHO groups, hypoechogenicity differed significantly among the groups (P = 0.01) and tended to increase in proportion as tumor invasiveness increased (P for trend = 0.02). In the alternative group, punctate echogenic foci were associated with prognosis (P = 0.03, P for trend = 0.03). Conclusion: Increasing tumor invasiveness and worsening prognosis in FTC based on the WHO classification and TERT promoter mutation results were positively correlated with US features that indicate malignant probability according to both K-TIRADS and ACR-TIRADS.

Diagnosis of Benzimidazole Resistance in Haemonchus contortus of Sheep by Allele Specific PCR

  • Tiwari, J.;Kolte, A.P.;Kumar, S.;Swarnkar, C.P.;Singh, D.;Pathak, K.M.L.
    • Asian-Australasian Journal of Animal Sciences
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    • v.20 no.1
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    • pp.7-11
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    • 2007
  • The study was conducted on 162 adult male Haemonchus contortus of sheep collected from Avikanagar, Jaipur and Bikaner regions to diagnose the benzimidazole (BZ) resistance in H. contortus. The BZ resistance is primarily linked with the mutation in ${\beta}$-tubulin isotype 1 gene which substitute phenylalanine (Phe) into tyrosine (Tyr) at the 200 codon of the gene. An allele specific polymerase chain reaction (AS-PCR) technique was used for diagnosis of BZ resistance in H. contortus. In AS-PCR, one reverse primer (TGG 312) was used in two separate reactions with each of 2 forward primers (resistant TGG 331 and susceptible CAW 106 primer) that differed only at 3' nucleotide position. Therefore, the amplified products from resistant and susceptible parasites were produced 267 and 266 bp, respectively. A total of 162 parasites were genotyped, of which 130 parasites found homozygous resistant 'rr', 22 heterozygous 'rS' and 10 homozygous susceptible 'SS' type. The prevalence of 'rr' individuals was higher in Jaipur (98%) followed by Avikanagar (93%) and Bikaner (50%) regions. Overall, the prevalence of BZ resistant allele (r) was higher (87%) as compared to 13% of BZ susceptible allele (S).

Selection of Target Materials for GLP Genotoxic Tests by Searching the Mutagenicity Information of Chemicals by Occupational Safety and Health Act (산안법 관리대상물질의 변이원성 검색을 통한 GLP 유전독성 시험대상 후보물질의 선정)

  • Rim, Kyung-Taek;Lim, Cheol-Hong;Ahn, Byung-Joon
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.25 no.3
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    • pp.254-284
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    • 2015
  • Objectives: There is a requirement to select target materials for mutagenicity(Genotoxicity) testing, so we determined to set the test priorities of them by searching the related database. Methods and Results: We searched a number of databases to find information on mutagenicity tests with chemicals under the Occupational Safety and Health Act(OSH Act), such as KOSHANET, National Toxicology Program(NTP), European Chemicals Agency(ECHA), US National Library of Medicine(NLM), and Genetic Toxicology Data Bank(GENE-TOX), as well as ChemIDplus webpage, and presented the information. Also we anticipated their hazards with ACToR sites to confirm the 58 mutagenicity(Genotoxicity) tests we will perform. Conclusions: We presented target materials for mutagenicity testing with specific GLP tests consisting of reverse mutation(Ames), chromosomal aberration and micronucleus test.

Genotoxicological Safety Evaluation of Crude Antifungal Compounds Produced by Bacillus subtilis SN7 (Bacillus subtilis SN7이 생성한 조항균 물질의 유전독성학적 안정성평가)

  • Chang, Hae-Choon;Koh, Sang-Bum;Lee, Jae-Joon
    • The Korean Journal of Community Living Science
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    • v.28 no.1
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    • pp.131-141
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    • 2017
  • This study was carried out to perform genotoxicological safety evaluation of crude antifungal compounds produced by Bacillus subtilis SN7 (B. subtilis SN7) isolated from meju. Bacterial reverse mutation assay with Salmonella typhimurium TA98, TA100, TA1535, and TA1537 or Escherichia coli WP2uvrA in the presence and absence of the S9 metabolic activation system was carried out, and the crude antifungal compounds produced by B. subtilis SN7 showed no significant increase in the number of revertant colonies. In the chromosomal aberration tests using Chinese hamster lung (CHL) cells, sample treatment groups showed no increase in the frequency of chromosome aberrations compared to the negative control group. Furthermore, in the micronucleus formation test, the crude antifungal compounds showed no significance increase in the frequency of polychromatic erythrocytes with micronuclei. These results suggest that the crude antifungal compounds produced by B. subtilis SN7 isolated from meju showed no harmful genotoxic effects.

Mutagenicity Studies on Nonspecific Immunostimulator BARODON® (비특이 면역증강제 BARODON®에 대한 유전독성시험)

  • 서민수;조성대;안남식;정지원;양세란;박준석;박기수;홍인선;조은혜
    • Toxicological Research
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    • v.19 no.2
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    • pp.141-146
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    • 2003
  • A nonspecific immunostimulator $BARODON^{\circledR}$ was tested for mutagenicity using Ames Salmonella tester strains TA98, TA1 00, TA 102, TA 1535 and TA 1537 with or without metabolic activation (59 mix). None of the fresh species showed mutagenicity. In the reverse mutation test using Salmonella phimurium TA98, TA100, TA102, TA1535 and TA1537 did not increase the number of revertants at all doses tested (5, 2.5 or 1.25 mg/ml). Chromosome aberration test was carried out in Chinese hamster lung (CHL) cell line. The cells were treated with $BARODON^{\circledR}$ (1, 0.5 or 0.25 mg/ml), while positive control group was treated with Mitomycin C (0.1 mg/ml). The results show that there is no statistically significant difference between positive control and treatment groups. In mouse micronucleus test, there was significant increase in the ratio of micronucleated polychromatic erythrocyte (MNPCE) in the high dose group (10% $BARODON^{\circledR}$), while there is no significance between control and low (2.5% $BARODON^{\circledR}$) or middle (5% $BARODON^{\circledR}$ dose groups. Taken together, this results suggest that below 5% $BARODON^{\circledR}$ might not have mutagenic potential in vitro and vivo systems.

Genotoxicity Assessment of Erythritol by Using Short-term Assay

  • Chung, Young-Shin;Lee, Michael
    • Toxicological Research
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    • v.29 no.4
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    • pp.249-255
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    • 2013
  • Erythritol is a sugar alcohol that is widely used as a natural sugar substitute. Thus, the safety of its usage is very important. In the present study, short-term genotoxicity assays were conducted to evaluate the potential genotoxic effects of erythritol. According to the OECD test guidelines, the maximum test dose was 5,000 ${\mu}g$/plate in bacterial reverse mutation tests, 5,000 ${\mu}g/ml$ in cell-based assays, and 5,000 mg/kg for in vivo testing. An Ames test did not reveal any positive results. No clastogenicity was observed in a chromosomal aberration test with CHL cells or an in vitro micronucleus test with L5178Y $tk^{+/-}$ cells. Erythritol induced a marginal increase of DNA damage at two high doses by 24 hr of exposure in a comet assay using L5178Y $tk^{+/-}$ cells. Additionally, in vivo micronucleus tests clearly demonstrated that oral administration of erythritol did not induce micronuclei formation of the bone marrow cells of male ICR mice. Taken together, our results indicate that erythritol is not mutagenic to bacterial cells and does not cause chromosomal damage in mammalian cells either in vitro or in vivo.

Genotoxicity Study of Glycopeptide (G-7%NANA)

  • Kim, Ha-Young;Kim, Min-Hee;Kim, Hee-Kyong;Park, Yeong-Chul
    • Toxicological Research
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    • v.34 no.3
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    • pp.259-266
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    • 2018
  • Glycomacropeptide (GMP), a whey protein of milk, has functions including differentiation and development of nervous system, and anticancer and antiviral effects. To develop new functions, N-acetylneuraminic acid (NANA) containing 7% sialic acid was separated from GMP to produce G-7%NANA. N-glycolylneuraminic acid (Neu5Gc) is another type of sialic acid separated from GMP, which has been linked to immune disorders and chronic inflammation-mediated diseases. Therefore, safety was a concern in the use of G-7%NANA in functional foods. To ensure safety, in this study, three genetic toxicity tests on G-7%NANA were conducted. In the reverse mutation test using Salmonella typhimurium TA98, TA100, TA1535, TA1537, and Escherichia coli WP2uvrA, and in the chromosome aberration test using CHO-K1 cells, no significant differences from negative control were found at all dose levels. Similarly, no dose-related differences were evident compared to negative control in the micronucleus test using ICR mice. There was no evidence of G-7%NANA-related genetic toxicity.