• Proceedings of the Microbiological Society of Korea Conference
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• 1998.04a
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• pp.63.1-63.1
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• 1998

• The Plant Pathology Journal
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• v.15 no.2
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• pp.105-111
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• 1999

• Korean Journal of Veterinary Service
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• v.30 no.4
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• pp.505-510
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• 2007

This study was conducted to detect ${\beta}$-lactam antibiotic-resistant genes in the 400 E coli isolates from porcine fecal samples in Korea by a DNA chip. The DNA chip contains the specific probe DNAs of the ${\beta}$-lactam antibiotic-resistant genes that had been labeled with a mixture of primer set designed to amplify specific genes (PSE, OXA, FOX, MEN, CMY, TEM, SHV, OXY and AmpC) using a multiplex polymerase chain reaction (PCR). Of 400 isolates 339 contained at least one ${\beta}$-lactamases gene. Resistance to ${\beta}$-lactamases was mediated mainly by AmpC (n = 339, 100%), and followed by TEM (n = 200, 59.0%), CMY (n = 101, 29.8%), PSE (n = 30, 8.9%) and both OXA and SHV genes (n = 20, 5.9%), while the FOX, MEN and OXY genes were not detected. The other sixty-one did not contain any ${\beta}$-lactamase genes even though they were resistant to antimicrobial drugs. In conclusion, the DNA chip system can be used as a rapid and reliable method for detecting of ${\beta}$-lactamases genes, which will help veterinarians select the antibiotics for monitoring and treating of animal diseases.

• The Plant Pathology Journal
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• v.17 no.2
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• pp.77-82
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• 2001

Erwinia amylovora causes a devastating disease called fire blight in rosaceous trees and shrubs such as apple, pear, and raspberry. To successfully infect its hosts, the pathogen requires a set of clustered genes termed hrp. Studies on the hrp system of E. amylovora indicated that it consists of three functional classes of genes. Regulation genes including hrpS, hrpS, hrpXY, and hrpL produce proteins that control the expression of other genes in the cluster. Secretion genes, many of which named hrc, encode proteins that may form a transmembrane complex, which is devoted to type III protein secretion. Finally, several genes encode the proteins that are delivered by the protein secretion apparatus. They include harpins, DspE, and other potential effector proteins that may contribute to proliferation of E. amylovora inside the hosts. Harpins are glycine-rich heat-stable elicitors of the hypersensitive response, and induce systemic acquired resistance. The pathogenicity protein DseE is homologous and functionally similar to an avirulence protein of Pseudomonas syringae. The region encompassing the hrpldsp gene cluster of E. amylovora shows features characteristic of a genomic island : a cryptic recombinase/integrase gene and a tRNA gene are present at one end and genes corresponding to those of the Escherichia coli K-12 chromosome are found beyond the region. This island, designated the Hrp pathogenicity island, is more than 60 kilobases in size and carries as many as 60 genes.

• Korean Journal of Clinical Laboratory Science
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• v.43 no.2
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• pp.68-74
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• 2011

Pseudomonas aeruginosa is an aerobic, Gram-negative, glucose-nonfermenting bacterium, which has emerged as a serious opportunistic pathogen. Recently, outbreaks of carbapenem resistant P. aeruginosa give rise to significant therapeutic challenges for treating nosocomial infections. The genes of metallo-${\beta}$-lactamase (MBL), a powerful carbapenemase, are carried as a part of the mobile gene cassettes inserted into integrons playing an important role in rapid dissemination of antibiotic resistance genes among bacterial isolates. In this study, we investigated the prevalence of integron in imipenem resistant P. aeruginosa isolates. A total of 61 consecutive, non-duplicate, and imipenem resistant P. aeruginosa strains were isolated from a university hospital in the Chungcheong province of Korea. We employed repetitive extragenic palindromic sequence-based PCR (rep-PCR) method for the selection of clonally different P. aerusinosa strains. PCR and DNA sequencing were conducted for the detection of integrons. Twenty-one clonally different P. aeruginosa strains were isolated. Only one (P28) of the strains harbored $bla_{VIM-2}$ that was found as gene cassettes in class 1 integrons. Four of 21 carbapenem resistant P. aeruginosa strains harbored class 1 integron containing aminoglycoside resistance determinant. All of the integrons detected in the study contained more than one resistance gene cassette, which can mediate resistance to multiple antibiotics. To prevent further spreading of the multi-drug resistant P. aeruginosa, conseguent monitoring and clinical polices are required.

• The Plant Pathology Journal
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• v.23 no.3
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• pp.187-192
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• 2007

The anthracnose disease on pepper fruits in Korea was caused by Colletotrichum acutatum as well as C. gloeosporioides. Since C. acutatum showed less sensitivity to benomyl, it was analyzed whether the less sensitivity was given by the same mechanism for the fungicide resistance of C. gloeosporioides. The isolates of C. acutatum were less sensitive to the three benzimidazole fungicides tested, benomyl, carbendazim, and thiophanate-methyl. However, the of C. acutatum isolates were different from the resistant isolates of C. gloeosporioides in their response to diethofencarb, one of N-phenyl-carbamates; the former was still less sensitive to diethofencarb than the latter. The differences in the resistance mechanisms in two species were conspicuous in sequence analysis of the tub2 genes. The genes from C. acutatum did not show any non-synonymous base substitutions at the regions known to be correlated with the benzimidazole-resistance. All of these data may indicate that the less sensitivity of C. acutatum to benomyl is based on different mechanism(s) from that of C. gloeosporioides.

• The Plant Pathology Journal
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• v.30 no.2
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• pp.220-227
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• 2014

The GacS/GacA system in the root colonizer Pseudomonas chlororaphis O6 is a key regulator of many traits relevant to the biocontrol function of this bacterium. Proteomic analysis revealed 12 proteins were down-regulated in a gacS mutant of P. chlororaphis O6. These GacS-regulated proteins functioned in combating oxidative stress, cell signaling, biosynthesis of secondary metabolism, and secretion. The extent of regulation was shown by real-time RT-PCR to vary between the genes. Mutants of P. chlororaphis O6 were generated in two GacS-regulated genes, trpE, encoding a protein involved in tryptophan synthesis, and prnA, required for conversion of tryptophan to the antimicrobial compound, pyrrolitrin. Failure of the trpE mutant to induce systemic resistance in tobacco against a foliar pathogen causing soft rot, Pectobacterium carotovorum SCCI, correlated with reduced colonization of root surfaces implying an inadequate supply of tryptophan to support growth. Although colonization was not affected by mutation in the prnA gene, induction of systemic resistance was reduced, suggesting that pyrrolnitrin was an activator of plant resistance as well as an antifungal agent. Study of mutants in the other GacS-regulated proteins will indicate further the features required for biocontrol-activity in this rhizobacterium.

• Korean Journal of Veterinary Research
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• v.52 no.3
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• pp.177-181
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• 2012

Actinobacillus (A.) pleuropneumoniae is the causative agent of pleuropneumonia which is one of the most important respiratory diseases in pigs worldwide. A total of 32 A. pleuropneumoniae isolates from diseased pigs during 2008 to 2010 were serotyped by polymerase chain reaction method. The susceptibility of the isolates to 13 antimicrobial agents were determined by disk diffusion test. In all the 32 isolates examined in this study, serotype 5 (16 isolates: 50%), 1 (7 isolates: 21.9%), 2 (5 isolates: 15.6%) and 12 (1 isolate: 3.1%) were found. Of all tested antimicrobial agents, resistance to oxytetracycline was found in 96.9% of isolates, followed by resistance to amikacin (81.2%), neomycin (68.7%), kanamycin (53.1%), penicillin (50.0%), gentamicin (43.7%), florfenicol (25.0%), ampicillin (18.7%), colistin (9.4%), trimethoprim/sulfamethoxazole, ceftiofur (8.3%), amoxicillin/clavulanic acid (3.1%) and enrofloxacin (0%). Oxytetracycline or florfenicol-resistant isolates were examined for the presence of resistance gene. Among the 31 oxytetracycline-resistant isolates, tetB, tetH and tetO genes were detected in 22 (71%), 8 (26%) and 1 (3%) isolates, respectively. The floR genes were detected in 8 (100%) of the 8 florfenicol-resistant A. pleuropneumoniae isolates.

• Journal of Microbiology and Biotechnology
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• v.29 no.3
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• pp.465-472
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• 2019

Several reports describe antimicrobial-resistance transfer among children and the community in outbreak situations, but transfer between a child and a caregiver has not been examined in child care facilities under normal circumstances. We investigated the transfer of antimicrobial-resistance genes, resistant bacteria, or both among healthy children and teachers. From 2007 to 2009, 104 Escherichia coli isolates were obtained from four teachers and 38 children in a child care center. Twenty-six cephem-resistant isolates were obtained from children in 2007 and 2008. In 2009, cephem-resistant isolates were detected in children as well as a teacher. Nalidixic acid-resistant isolates from the same teacher for 3 years showed low similarity (<50%) to each other. However, an isolate from a teacher in 2007 and another from a child in 2008 showed high similarity (87%). Pulsed-field gel electrophoresis revealed 100% similarity for four isolates in 2007 and one isolate in 2008, and also similarity among seven isolates carrying the virulence gene (CNF1). This study yielded the following findings: (1) a gene for extended-spectrum ${\beta}$-lactamase was transferred from a child to other children and a teacher; (2) a nalidixic acid-resistant isolate was transferred from a teacher to a child; and (3) a virulent bacterium was transferred between children.

• Journal of Crop Science and Biotechnology
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• v.11 no.2
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• pp.101-106
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• 2008

To identify inheritance of clubroot disease resistance genes in Chinese cabbage, seedling tests of $BC_1P_1,\;BC_1P_2$, and $F_2$ populations derived from $F_1$ hybrid(var. CR Saerona) using single spore isolate(race 4 identified with William's differential host) from Plasmodiophora brassciae were conducted. Resistance(R) and susceptible(S) plants segregated to 1:0 in backcross to the resistant parent. The $F_2$ population segregated in a 3(R):1(S) ratio. This result implied that the resistance of clubroot disease is controlled by a single dominant gene to the race 4 of P. brassicae in CR Saerona. To develop DNA markers linked to clubroot resistance genes, 185 plants of CR Saerona among $F_2$ populations were used. A total of 300 arbitrary decamer was applied to $F_2$ population using BSARAPD(Bulked segregant analysis-Randomly amplified polymorphic DNA). One RAPD marker linked to clubroot resistance gene in CR Saerona($OPJ_{1100}$) was identified. This marker was 3.1 cM in distance from resistance gene in $F_2$ population. This marker may be useful for a marker-assisted selection(MAS) and gene pyramiding of the clubroot disease resistant gene in Chinese cabbage breeding programs.