• Molecular & Cellular Toxicology
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• 제1권3호
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• pp.172-178
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• 2005

[ $21{\alpha}$ ]- and ${\beta}$-Methylmelianodiol were isolated as the inhibitor of IL-5 bioactivity from Poncirus tripoliata. To develope as an anti-septic drug, the genotoxicity of $21{\alpha}\;-and\;{\beta}-methylmelianodiol$ was subjected to high throughput toxicity screening (HTTS) because they revealed strong IL-5 inhibitory activity and limitation of quantity. Mouse lymphoma thymidine kinase ($tk^{+/-}$) gene assay (MOLY), single cell gel electrophoresis (Comet) assay in mammalian cells and Ames reverse mutation assay in bacterial system were used as simplified, inexpensive, short-term in vitro screening tests in our laboratory. These compounds are not mutagenic in S. typhimurium TA98 and TA100 strains both in the presence and absence of metabolic activation. Before performing the comet assay, $IC_{20}$ of $21{\alpha}-methylmelianodiol$ was determined the concentration of $25.51\;{\mu}g/mL\;and\;21.99\;{\mu}g/mL$ with and without S-9, respectively. Also $21{\beta}-methylmelianodiol$ was determined the concentration of $24.15\;{\mu}g/mL\;and\;\;22.46\;{\mu}g/mL$ with and without S-9, respectively. In the comet assay, DNA damage was not observed both $21{\alpha}-methylmelianodiol\;and\;21{\beta}-methylmelianodiol$ in mouse lymphoma cell line. Also, the mutant frequencies in the treated cultures were similar to the vehicle controls, and none of $21{\alpha}\;-and\;{\beta}-methylmelianodiol$ with and without S-9 doses induced a mutant frequency over. twice the background. It is suggests that $21{\alpha}\;-and\;{\beta}-methylmelianodiol$ are non-mutagenic in MOLY assay. The results of this battery of assays indicate that $21{\alpha}\;-and\;{\beta}-methylmelianodiol$ have no genotoxic potential in bacterial or mammalian cell systems. Therefore, we suggest that $21{\alpha}\;-and\;{\beta}-methylmelianodiol$, as the optimal candidates with both no genotoxic potential and IL-5 inhibitory effects must be chosen.

• 한국식품위생안전성학회지
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• 제16권2호
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• pp.145-151
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• 2001

유아 식품중의 병마개 등에 약 30%까지 함유되어 합성수지 및 고무의 가소제로 많이 사용되고 있으나 최근 유럽등지에서 식품으로의 유리가 보고되어 안전성에 대한 재평가가 요구되어지고 있는 에폭시화 대두유 (Epoxidized soy bean oil, ESBO)의 유전독성을 평가하기 위해서 박테리아를 이용한 복귀돌연변이시험과 포유류 배양세포를 대상으로 검색하는 체외 염색체이상시험, 설치류의 조혈세포를 이용한 체내 소핵시험을 수행하였다. Salmonella typhimurium TA98, TA100, TA1535, TA1537, TA102균주를 이용한 복귀돌연변이 시험결과 직접법 및 대사활성화법에서 돌연변이 유발성을 가지지 않는 음성의 결과를 나타내었으며, chinese hamster lung cell을 이용한 염색체이상시험을 실시한 결과, 직접법 및 대사활성화법에서 염색체이상 유발작용을 보이지 않는 음성의 결과를 나타내었다. 또한 성별, 연령별에 따라서 마우스 골수세포를 이용한 소핵시험에서 에폭시화 대두유는 미성숙 적혈구중 유의성 있는 소핵 유발은 관찰되지 않았다. 이상의 결과를 종합하여, 본 시험조건 중 에폭시화 대두유는 in vitro 시험인 Salmonella 균주를 이용한 복귀돌연변이시험과 포유동물 배양세포를 이용한 염색체이상시험 및 in vivo 시험인 마우스를 이용한 소핵시험에서 유전독성을 유발하지 않는 것으로 판단된다.

• 한국식품위생안전성학회지
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• 제31권2호
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• pp.107-112
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• 2016

본 연구는 발효 탐라오가피(fermented A. koreanum) 추출물의 유전독성을 연구하기 위하여, 미생물복귀돌연변이 시험, 마우스 골수세포를 이용한 소핵시험, 염색체 이상시험을 연구하였다. 미생물복귀돌연변이 연구에서 발효 탐라오가피 추출물은 Salmonella typhimurium TA98, TA100, TA1535, TA1537와 Escherichia coli WP2uvrA에 대하여 대사활성계의 존재(+S-9 Mix) 및 부재(-S-9 Mix) 하에서 돌연변이 유도를 보이지 않았다. 또한, ICR 마우스를 이용한 소핵실험에서 발효 탐라오가피 추출물은 500, 1,000, 2,000 mg/kg 농도에서 MNPCE/2,000 PCE 와 PCE/200 RBC의 소핵형성을 유발하지 않았다. 한편, CHO-K1 세포를 이용한 염색체 이상실험에서 발효 탐라오가피 추출물은 대사활성계의 존재 6시간 처리군, 대사활성계 부재 6시간 처리군 및 대사활성계 부재 24시간 처리군에서 염색체 이상을 보이지 않았다. 따라서, 본 연구결과 발효 탐라 오가피 추출물은 유전독성을 나타내지 않음을 알 수 있었다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.20-20
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• 2017

Plant genomes include heterochromatic loci that consist of repetitive sequences and transposable elements. LTR retrotransposon is the major class of transposons in advanced plants in terms of proportion in plant genome. The elements contribute not only to genome size but also to genome stability and gene expression. A number of cases have been reported transposon insertions near genic regions affect crop traits such as fruit pigments, stress tolerance, and yields. Functional LTR retrotransposons produce extrachromosomal DNA from genomic RNA by reverse transcription that takes place within virus-like-particles (VLPs). DECREASED DNA METHYLATION 1 (DDM1) plays important roles in maintaining DNA methylation of heterochromatin affecting all sequence contexts, CG, CHG, and CHH. Previous studies showed that ddm1 mutant exhibits massive transcription of retrotransposons in Arabidopsis, but only few of them were able to create new insertions into the genome. RNA-dependent RNA POLYMERASE 6 (RDR6) is known to function in restricting accumulation of transposon RNA by processing the transcripts into 21-22 nt epigenetically activated small interfering RNA (easiRNA). We purified VLPs and sequence cDNA to identify functional LTR retrotransposons in Arabidopsis ddm1 and ddm1rdr6 plants. Over 20 LTR copia and gypsy families were detected in ddm1 and ddm1rdr6 sequencing libraries and most of them were not reported for mobility. In ddm1rdr6, short fragments of ATHILA gypsy elements were detected. It suggests easiRNAs might regulate reverse transcription steps. The highest enriched element among transposon loci was previously characterized EVADE element. It has been reported that active EVADE element is more efficiently silenced through female germline than male germline. By genetic analyses, we found ddm1 and rdr6 mutation affect maternal silencing of active EVADE elements. DDM1-GFP protein accumulated in megaspore mother cell but was not found in mature egg cell. The fusion protein was also found in early embryo and maternal DDM1-GFP allele was more dominantly expressed in the embryo. We observed localization of DDM1-GFP in Arabidopsis and DDM1-YFP in maize and found the proteins accumulated in dividing zone of root tips. Currently we are looking at cell cycle dependency of DDM1 expression using maize system. Among 10 AGO proteins in Arabidopsis, AGO9 is specifically expressed in egg cell and shoot meristematic cells. In addition, mutation of AGO9 and RDR6 caused failure in maternal silencing, implying 21-22 nt easiRNA pathway is important for retrotransposon silencing in female gametophyte or/and early embryo. On the other hand, canonical 24 nt sRNA-directed DNA methylation (RdDM) pathways did not contribute to maternal silencing as confirmed by this study. Heat-activated LTR retrotransposon, ONSEN, was not silenced by DDM1 but the silencing mechanisms require RdDM pathways in somatic cells. We will propose distinct mechanisms of LTR retrotransposons in germline and somatic stages.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.97-97
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• 2017

Plant genomes include heterochromatic loci that consist of repetitive sequences and transposable elements. LTR retrotransposon is the major class of transposons in advanced plants in terms of proportion in plant genome. The elements contribute not only to genome size but also to genome stability and gene expression. A number of cases have been reported transposon insertions near genic regions affect crop traits such as fruit pigments, stress tolerance, and yields. Functional LTR retrotransposons produce extrachromosomal DNA from genomic RNA by reverse transcription that takes place within virus-like-particles (VLPs). DECREASED DNA METHYLATION 1 (DDM1) plays important roles in maintaining DNA methylation of heterochromatin affecting all sequence contexts, CG, CHG, and CHH. Previous studies showed that ddm1 mutant exhibits massive transcription of retrotransposons in Arabidopsis, but only few of them were able to create new insertions into the genome. RNA-dependent RNA POLYMERASE 6 (RDR6) is known to function in restricting accumulation of transposon RNA by processing the transcripts into 21-22 nt epigenetically activated small interfering RNA (easiRNA). We purified VLPs and sequence cDNA to identify functional LTR retrotransposons in Arabidopsis ddm1 and ddm1rdr6 plants. Over 20 LTR copia and gypsy families were detected in ddm1 and ddm1rdr6 sequencing libraries and most of them were not reported for mobility. In ddm1rdr6, short fragments of ATHILA gypsy elements were detected. It suggests easiRNAs might regulate reverse transcription steps. The highest enriched element among transposon loci was previously characterized EVADE element. It has been reported that active EVADE element is more efficiently silenced through female germline than male germline. By genetic analyses, we found ddm1 and rdr6 mutation affect maternal silencing of active EVADE elements. DDM1-GFP protein accumulated in megaspore mother cell but was not found in mature egg cell. The fusion protein was also found in early embryo and maternal DDM1-GFP allele was more dominantly expressed in the embryo. We observed localization of DDM1-GFP in Arabidopsis and DDM1-YFP in maize and found the proteins accumulated in dividing zone of root tips. Currently we are looking at cell cycle dependency of DDM1 expression using maize system. Among 10 AGO proteins in Arabidopsis, AGO9 is specifically expressed in egg cell and shoot meristematic cells. In addition, mutation of AGO9 and RDR6 caused failure in maternal silencing, implying 21-22 nt easiRNA pathway is important for retrotransposon silencing in female gametophyte or/and early embryo. On the other hand, canonical 24 nt sRNA-directed DNA methylation (RdDM) pathways did not contribute to maternal silencing as confirmed by this study. Heat-activated LTR retrotransposon, ONSEN, was not silenced by DDM1 but the silencing mechanisms require RdDM pathways in somatic cells. We will propose distinct mechanisms of LTR retrotransposons in germline and somatic stages.

• 한국식품위생안전성학회지
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• 제25권3호
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• pp.215-219
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• 2010

본 연구는 섬오갈피 뿌리 추출물을 이용하여 돌연변이 유발을 관찰하기 위해 S. typhimurium TA100, TA98, TA1535, TA1537과 E. coli WP2 uvr A를 이용해 Ames test을 하였고 또한 S. typhimurium TA100, TA98을 이용한 항돌연변이원 억제 시험을 시행하였다. Ames test에 필요한 시험물질들은 최고농도 결정을 통해 $5000\;{\mu}g$/plate, $2500\;{\mu}g$/plate, $600\;{\mu}g$/plate의 시험물질을 양성대조군, 실험군, 음성대조군을 비대사활성계와 대사활성계로 나누어 시험을 시행하였다. 시험 결과 모든 농도에서는 집락군의 일관성 있는 증가는 보이지 않았고 이 점으로 미루어 보아 복귀돌연변이는 일어나지 않았고 음성으로 판정하였다. 항돌연변이원 시험에서는 양성물질의 농도결정과 시험물질의 최고농도 결을 통해 양성대조군, 실험군, 음성대조군을 비대사활성계와 대사활성계로 시험을 하였고 시험결과 S. typhimurium TA100, TA98 두 균주 돌연변이 억제를 보였으며 TA98에서 더 높은 억제율을 보였다. 시험결과로 섬오갈피의 뿌리는 항돌연변이 억제효과에 탁월한 효과가 있음을 시사하였다.

• Journal of Animal Science and Technology
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• 제50권2호
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• pp.177-184
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• 2008

Acid-labile subunit(ALS)는 85-kDa 크기의 당단백질로서 7.5-kDa의 insulin-like growth factor(IGF) 및 40~45-kDa IGF-binding protein-3와 결합하여 150-kDa ternary complex를 형성하는 혈장단백질이다. 선행연구에서 본 연구진은 reverse transcription-polymerase chain reaction(RT-PCR) 방법으로 돼지(porcine) ALS(pALS)의 coding sequence를 합성하여 plasmid vector에 삽입시켜 ‘expression construct’를 제작한 바 있다. 그러나 본 expression construct의 pALS coding sequence에는 PCR error로 추정되는 원인으로 말미암아 2개의 bases에서 mis-sense mutation이 일어난 것이 발견되었다. 본 연구에서는 ‘site-directed mutagenesis’ 방법으로 pALS의 올바른 coding sequence를 합성하여 ‘insert DNA’의 마지막 codon 다음에 ‘His-tag’ sequence가 위치한 pET- 28a(+) plasmid expression vector에 삽입하였다. 본 expression construct는 E. coli BL21(DE3) 세포에서 ‘induction’ 시켰고, 발현된 유전자재조합(recombinant) peptide는 Ni-affinity chromato- graphy로 정제하였다. 이렇게 affinity chro- matography로 정제된 peptide는 SDS-PAGE에서 66kDa 위치에 single band를 나타냄으로써 recombinant pALS의 예상된 질량과 일치하였다. 이상의 결과는 본 연구에서 recombinant pALS peptide가 성공적으로 발현정제되었음을 시사한다.

• Tuberculosis and Respiratory Diseases
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• 제72권1호
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• pp.44-49
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• 2012

Background: Multidrug-resistant tuberculosis (MDR-TB) is an increasing public health problem and poses a serious threat to global TB control. Fluoroquinolone (FQ) and aminoglycoside (AG) are essential anti-TB drugs for MDR-TB treatment. REBA MTB-FQ$^{(R)}$ and REBA MTB-KM$^{(R)}$ (M&D, Wonju, Korea) were evaluated for rapid detection of FQ and kanamycin (KM) resistance in MDR-TB clinical isolates. Methods: M. tuberculosis (n=67) were isolated and cultured from the sputum samples of MDR-TB patients for extracting DNA of the bacilli. Mutations in genes, gyrA and rrs, that have been known to be associated with resistance to FQ and KM were analyzed using both REBA MTB-FQ$^{(R)}$ and REBA MTB-KM$^{(R)}$, respectively. The isolates were also utilized for a conventional phenotypic drug susceptibility test (DST) as the gold standard of FQ and KM resistance. The molecular and phenotypic DST results were compared. Results: Sensitivity and specificity of REBA MTB-FQ$^{(R)}$ were 77 and 100%, respectively. Positive predictive value and negative predictive value of the assay were 100 and 95%, respectively, for FQ resistance. Sensitivity, specificity, positive predictive value and negative predictive value of REBA MTB-KM$^{(R)}$ for detecting KM resistance were 66%, 94%, 70%, and 95%, respectively. Conclusion: REBA MTB-FQ$^{(R)}$ and REBA MTB-KM$^{(R)}$ evaluated in this study showed excellent specificities as 100 and 94%, respectively. However, sensitivities of the assays were low. It is essential to increase sensitivity of the rapid drug resistance assays for appropriate MDR-TB treatment, suggesting further investigation to detect new or other mutation sites of the associated genes in M. tuberculosis is required.

• 대한의생명과학회지
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• 제10권1호
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• pp.55-63
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• 2004

Bovine leukemia virus (BLV) is a causative agent for lymphoma disease in cattle including cows worldwide. BLV shares similar virion structure and characteristics with other retroviruses. The pol gene of the BLV genome produced reverse transcriptase (RT) and integrase (IN) for important roles for BLV genome integration into host cell chromosomes that is known to be coded in the 3' side of the BLV pol gene (one third portion). In this study, we have sequenced 978 bp in the 3' side of the BLV pol gene from BLV 10C3 in order to determine the BLV IN region of it. And we compared it to the nucleotide sequences of an Australian BLV isolate. As a result, nucleotide sequences of the IN region of the Korean-type BLV pol gene were mutated at a rate of 3.7%. We can confirm that the typical mutations are such as Arg (AGG) $\rightarrow$ Lys (AAG), Thr (ACG) $\rightarrow$ Met (ATG), Ile (ATT) $\rightarrow$ Val (GTT), Asn (ACC) $\rightarrow$ His (CAC), Phe (TTT) $\rightarrow$ Leu (TTG) and Asn (ACC) $\rightarrow$ Asp (GAC). From the analysis of the sequencing data, we were able to determine the zinc-finger-like "HHCC" motif in the amino terminus of BLV IN, that was H-$X_3$-H-$X_{25}-C-X_2$-C. It was also found the DD35E motif in the IN catalytic domain as D-$X_{56}$-D-$X_{35}$-E. It fits very well to the consensus sequences of retroviral IN as well as HHCC motif.

• 한국가축번식학회지
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• 제25권4호
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• pp.381-388
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• 2001

본 연구는 돼지에서 성장호르몬과 결합되는 부위에 변이를 유도하여 결합력이 향상된 성장호르몬 결합단백질을 획득하기 위하여 수행되었다. 돼지의 지방으로부터 얻은 성장호르몬 수용체 RNA 내 성장호르몬 결합단백질 부분을 756 bp의 cDNA로 전향하고 클로닝한 후 site-directed mutagenesis 방법을 이용하여 26과 122번째 아미노산을 변이시켰다. 26번째 아미노산은 성장 호르몬과의 결합에 관련이 있다고 알려져 있는 돼지 성장호르몬 수용체 외막에 존재하는 다섯 군데의 N-linked glycosylation 부위와 가까이 위치한 부분이고, 122번째 아미노산은 소에서의 결합부위로 알려져 있다. 이렇게 변이를 유도한 성장호르몬 결합 단백질을 pET-32(c) 발현벡터에 삽입시키고 과발현시켰고 이를 정제하여 30 kDa의 변이를 유도한 성장호르몬 결합 단백질을 얻었다. 이러한 방법으로 성장호르몬 결합 단백질을 성장기에 있는 세포나 동물에 주입한다면 보다 향상된 성장을 볼 수 있을 것으로 사료된다.