• KSBB Journal
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• v.25 no.2
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• pp.199-204
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• 2010

We generated the feasibility of DNA separation in free-solution using genetically engineered repetitive polypeptides as drag-tags. Two different-sized repetitive polypeptides were designed, expressed in E. coli, and purified. They were conjugated to a fluorescently labeled DNA (100 base), and the electrophoretic mobilities of these conjugate molecules were analyzed on a microchip. The results of these studies indicate that genetically engineered repetitive polypeptide is a prominent candidate for rapid and high-throughput genetic mutation detection, such as SNP analysis.

• KSBB Journal
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• v.22 no.4
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• pp.179-184
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• 2007

This study introduces the characteristics and some applications of repetitive polypeptides, especially to the biomaterial, tissue engineering scaffolds, drug delivery system, and DNA separation systems. Since some fibrous proteins, which consist of repeating peptide monomers, have been reported that their physical properties are changed dramatically by means of temperature alteration or pH shifting. For that reason, fibrous protein-mimetic polypeptides, which are produced by the recombinant technology, can be applied to the diverse biological fields. Repetitive polypeptides can also be used in the bioseparation area such as DNA sequencing, because they make DNA separation possible in free-solution electrophoresis by conjugating DNA fragments to them. Moreover, artificial synthesis of repetitive polypeptides helps to demonstrate the correlations between mechanical properties and structures of natural protein polymer, which have been proven that repetitive domains are affected by the sequence of the repeating domains and the number of repeating subunits. Repetitive polypeptides can be biologically synthesized using some special cloning methods, which are represented here. Recursive directional ligation (RDL) and controlled cloning method (CCM) have been proposed as excellent cloning methods in that we can control the number of repetition in the multimerization of polypeptides and the components of repetitive polypeptides by either method.

• The Korean Journal of Mycology
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• v.30 no.1
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• pp.66-72
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• 2002

To develop DNA markers for analysis of genetic characteristics of Phytophthora capsici population, randomly selected clones from HindIII-digested genomic DNA library of P. capsici 95CY3119 were surveyed by hybridizing to Southern blots of HindIII-digested total genomic DNA of P. capsici. Probe DNAs inserted into selected individual clones strongly hybridized with HindIII digests of P. capsici. Among probes examined, PC9 revealed the repetitive and highly polymorphic bands to HindIII digests of inter-and intra-field P. capsici isolates. Genetic diversity of individual isolates was also clearly revealed in cluster analysis based on its band patterns. The other probe, PC22, was hybridized only to DNA from P. capsici and this was highly repetitive. However, there was no response to other Phytophthora species and Pythium sp. These DNA probes could be used as very useful markers in analysing genetic diversity and identification for P. capsici population throughout the world.

• Journal of Microbiology and Biotechnology
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• v.22 no.1
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• pp.13-24
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• 2012

The genetic diversity of plant growth-promoting rhizobacterial (PGPR) fluorescent pseudomonads associated with the sugarcane (Saccharum officinarum L.) rhizosphere was analyzed. Selected isolates were screened for plant growthpromoting properties including production of indole acetic acid, phosphate solubilization, denitrification ability, and production of antifungal metabolites. Furthermore, 16S rDNA sequence analysis was performed to identify and differentiate these isolates. Based on 16S rDNA sequence similarity, the isolates were designated as Pseudomonas plecoglossicida, P. fluorescens, P. libaniensis, and P. aeruginosa. Differentiation of isolates belonging to the same group was achieved through different genomic DNA fingerprinting techniques, including randomly amplified polymorphic DNA (RAPD), amplified ribosomal DNA restriction analysis (ARDRA), repetitive extragenic palindromic (REP), enterobacterial repetitive intergenic consensus (ERIC), and bacterial repetitive BOX elements (BOX) analyses. The genetic diversity observed among the isolates and rep-PCR-generated fingerprinting patterns revealed that PGPR fluorescent pseudomonads are associated with the rhizosphere of sugarcane and that P. plecoglossicida is a dominant species. The knowledge obtained herein regarding the genetic and functional diversity of fluorescent pseudomonads associated with the sugarcane rhizosphere is useful for understanding their ecological role and potential utilization in sustainable agriculture.

• Korean Journal of Ecology and Environment
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• v.33 no.3 s.91
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• pp.206-212
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• 2000

Since some cyanobacterial isolates under selective culturing conditions are lacking of characteristic specialized cells or showing altered morphology, the morpho-taxonomic criteria are not accurate enough to discriminate between species. Instead of morphological parameters, a method based on the single or the combination of repetitive oligonucleotides in a single PCR, repetitive oligonucleotides-primed PCR (ROP-PCR), was applied to generate DNA profiles for members of the cyanobacterial genera Anabaena and Oscillatoria, both of which are responsible for causing poisonous blooms in various freshwater systems. ROP-PCR performed on 10 isolates of the cyanobacteria with ERIC and REP sequences from gram-negative bacteria, STRR1A and LTRR sequences derived from cyanobacterial genome, and eukaryotic repetitive sequences, led to the identification of distinct genotypes, and provided specific and repeatable DNA fingerprints for cyanobacterial isolates. Grouping analysis of cyanobacterial isolates showed a signifiant difference depending on the primer used in PCR.

• Korean journal of applied entomology
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• v.36 no.1
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• pp.96-104
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• 1997

A silkworm Bombyx mori genomic DNA library was constructed from polyphagous J111 strain and unpolyphagous $C_3$ strain to develop the genomic study by DNA makers. Genomic DNAs of two strains were digested with restriction enzyme EcoRI and ligated into pUC18. The ligated plasmids were transferred into E. coli host strain DH5$\alpha$. When the genomic DNAs were hybridized with insert DNAs from transformant, could be categorized from hybridization patterns to three groups as high repetitive sequence, moderately repetitive sequence, and low-copy number sequences. A total of 219 clones containing single or low-copy number sequence inserts were examined for any polymorphisms between two strains of J111 and $C_3$. Forty six clones showed RFLPs and 10 of these clones were used as a probe of analysis of $F_2$ population derived from crossing between J111 and $C_3$ strain. The genetic inheritance tested with each clones will be important tools to construct the genetic map of the silkworm, Bombyx mori.

• Korean Journal Plant Pathology
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• v.12 no.4
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• pp.389-394
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• 1996

도열병균, Magnaporthe grisea, 균주간의 유전적 유연관계를 분석하고 그들의 유전에 관한 '기본 정보를 얻고자 DNA polymorphism 분석을 실시하였다. 기주가 다른 도열병 균주들이 공시되었고 cloning에 의해 벼 도열병균 KJ201레이스 균주로부터 생성된 임의 선발 genomic clone들이 공시균주들간의 polymorphism을 밝히기 위해 사용되었던 바 그중 repectitive sequence를 보유한 repeated copy clone 하나가 선발되었다. Clone pMJ6에 의해 밝혀진 repetitive sequence는 Southern hybridization시 벼 분리균주에는 약 30개, 다른 기주 분리균에도 20∼33개의 밴드를 형성하였다. 반면 피 분리균주에는 단지 두 개의 밴드만을 나타내 분리기주가 다른 균주간에 뚜렷한 polymorphism이 존재하였으며 parsimony 분석에서도 역시 아주 먼 cluster를 형성하여 피 분리균은 다른 기주 분리균과 유전적으로 상당히 먼 것으로 추정되었다. 공시균의 genomic DNA를 HindIII로 처리했을 때 pMJ6에 의한 밴드양상은 공시균을 EcoRI으로 처리했을 때의 MGR probe의 밴드 양상과 유사하여 이 repeated copy clone이 도열병균주간의 유전적 유연관계를 분석하는데 MGR 못지않게 유용할 것으로 보인다.

• Journal of Plant Biology
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• v.39 no.1
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• pp.49-55
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• 1996

We have studied the DNA of Allium sativum L. with respect to highly repetitive sequences. Fast reassociated DNA fragments expected to be highly repetitive sequences based on $C_{o}t$ curve were isolated and characterized. Their copy numbers were approximately $10^{5}~10^{7}$ per haploid genome. Nucleotide sequences analysis of six candidates reveals that their G/C content were low, 25-40% and typical patterns of repeating sequences exist. Repeat sequences were used as probes to access restriction fragment length polymorphism (RFLP) of genomic DNAs of four local clones, Tanyang, Mungyong, So san, and Uisong. The hybridization pattern were very similar among these four local clones.clones.

• The Korean Journal of Mycology
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• v.25 no.4 s.83
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• pp.362-368
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• 1997

Five formae speciales of Fusarium oxysporum in Korea were examined using RFLP analysis to find the possibility for classification and analyze genetic variations. DNAs from F. oxysporum f. sp. lycopersici, cucumerinum, fragariae, garlic and sesami were used with three recombinant probes such as pFC46, pFC52 and pFC57. Distinct differences among five formae speciales of this fungus were detected in RFLP band patterns based on southern hybridization of genomic DNA using each recombinant clone, which was a repetitive copy probe. Strains belong to four formae speciales could be very stable in genetic variation except f. sp. sesami which has more variation than the others based on the RFLP analysis. They formed their own cluster which has high similarity within the same formae specialis resulted from the UPGMA analysis for genetic relationship analysis and each cluster represented its own formae specialis. The method using three recombinant DNA probes could be a good tool for classification of formae speciales in F. oxysporum.

• Korean Journal of Food Science and Technology
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• v.37 no.4
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• pp.611-617
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• 2005

Dispersed repetitive DNA elements in genomes of microorganisms differ among and within species. Because distances between repetitive sequences vary depending on bacterial strains, genomic fingerprinting with interspersed repetitive sequence-based probes can be used to distinguish unrelated organisms. Among well-known bacterial repetitive sequences, Repetitive Extragenic Palindromic (REP) sequence has been used to identify environmental bacterial species and strains. We applied REP-PCR to detect and differentiate four major Gram-negative food-borne bacterial pathogens, E. coli, Salmonella, Shigella, and Vibrio. Target DNA fragments of these pathogens were amplified by REP-PCR method. PCR-generated DNA fragments were separated on 1.5% agarose gel. Dendrograms for PCR products of each strain were constructed using photo-documentation system. REP-PCR reactions with primer pairs REP1R-I and REP2-I revealed distinct REP-PCR-derived genomic fingerprinting patterns from E. coli, Salmonella, Shigella, and Vibrio. REP-PCR method provided clear distinctions among different bacterial species containing REP-repetitive elements and can be widely used for typing food-borne Gram-negative strains. Results showed established REP-PCR reaction conditions and generated dendrograms could be used with other supplementary genotyping or phenotyping methods to identify isolates from outbreak and to estimate relative degrees of genetic similarities among isolates from different outbreaks to determine whether they are clonally related.