• Journal of Microbiology
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• 제41권1호
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• pp.1-6
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• 2003

The genetic relatedness of multidrug-resistant pneumococcal isolates of serotypes 19F and 23F was investigated. The DNA fragments digested with Sma I were resolved by pulsed-field gel electrophoresis (PFGE). PFGE analysis of 365. pneumoniae isolates showed 13 different patterns. Among 22 isolates of serotype 19F, 9 different PFGE patterns were present and 14 isolates of serotype 23F isolates represented 5 distinct PFGE patterns. Two isolates of serotype 19F and six isolates of serotype 23F shared the same PFGE pattern (Pattern I). Based on the genetic relatedness within the strains (one genetic cluster was defined as having more than 85% homology), we divided the pneumococcal strains into genefic clusters (Ⅰ, II, III, IV, V, and VI). The 22 strains of serotype 19F belonged to five distinct genetic clusters (I, II, III, IV, V and VI) and 14 strains of serotype 23F represented two genetic clusters (I and II ). These results showed that strains of serotype 19F are genetically more diverse than those of serotype 23F, Serotype 19F isolates with PFGE patterns H and I appeared to be less related to those of the remaining PFCE patterns (A to G) (less than 60% genetic relatedness), but those strains were genetically closely related with serotype 23f. These results suggest that the latter isolates originated from horizontal transfer of the capsular type 19F gene locus to 23F pneumococcal genotypes. In conclusion, the multidrug-resistant pneumococcal isolates of serotype 19f and 23F isolated in Korea are the result of the spread of a limited number of resistant clones.

• Journal of Plant Biotechnology
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• 제46권3호
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• pp.205-216
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• 2019

Since the RNA interference (RNAi) had been discovered in many organisms, small non-coding RNA-mediated gene silencing technology, including RNAi have been widely applied to analysis of gene function, as well as crop improvement. Despite the usefulness of RNAi technology, RNAi transgenic crops have various potential environmental risks, including off-target and non-target effects. In this study, we developed methods that can be effectively applied to environmental risk assessment of RNAi transgenic crops and verified these methods in 35S::dsRNAi_eGFP rice transgenic plant we generated. Off-target genes, which can be non-specifically suppressed by the expression of dsRNAi_eGFP, were predicted by using the published web tool, pssRNAit, and verified by comparing their expressions between wild-type (WT) and 35S::dsRNAi_eGFP transgenic rice. Also, we verified the non-target effects of the 35S:: dsRNAi_eGFP plant by evaluating horizontal and vertical transfer of small interfering RNAs (siRNAs) produced in the 35S::dsRNAi_eGFP plant into neighboring WT rice and rhizosphere microorganisms, respectively. Our results suggested that the methods we developed, could be widely applied to various RNAi transgenic crops for their environmental risk assessment.

• 생명과학회지
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• 제29권1호
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• pp.123-128
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• 2019

원핵생물 분류의 기본단위인 종(species)의 동정에 16S rDNA가 사용되지만 한계가 있고 원핵생물의 속(genus)에 대한 연구가 많지 않다. 본 연구에서는 보존 유전자를 확보한 COG database와 대사경로를 확보한 MetaCyc database에 공통적인 원핵생물 중 속이 같고 종이 다른 13개 속 28개의 원핵생물을 대상으로 속 수준에서 연구하였다. 전체 유전자에서 core-genome인 속 보존 유전자의 비율은 최저 27.62%(Nostoc 속)에서 71.76%(Spiribacter 속)의 범위로 평균 46.72%였다. 각 원핵생물에서 core-genome의 비율이 낮으면 특이한 생명현상을 보이거나 서식지가 다양할 수 있을 것이다. 속 수준의 공통 대사경로의 비율은 최저 58.79%(Clostridium 속)에서 최대 96.31%(Mycoplasma 속), 평균 75.86%로 core-genome의 비율보다 높았다. 비교대상을 확장하면 속 특이 보존 유전자와 대사경로는 확인할 수 없었다. 보존 유전자와 대사경로 보유 계통수에서는 대체로 같은 속의 구성원들이 가장 인접하였으며, Bacillus속과 Clostridium 속이 그룹을 형성하였고, 고세균끼리 그룹을 형성하였다. 보존 유전자 보유계통수에서는 Acidobacteria, Cyanobacteria, Proteobacteria 문(phylum)의 Granulicella, Nostoc, Bradyrhizobium의 3개 속이 하나의 그룹을 형성하였다. 본 연구 결과는 (i) 각 계통 단계에서 보존유전자와 대사경로의 확인, (ii) 수평적 유전자 전달 또는 부위 지정 돌연변이를 통한 균주의 개선 등의 분야에 기초자료로 활용될 수 있을 것이다.