• Journal of Microbiology and Biotechnology
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• 제26권2호
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• pp.263-269
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• 2016

Temperate phages have been suggested to carry virulence factors and other lysogenic conversion genes that play important roles in pathogenicity. In this study, phage TEM123 in wild-type Staphylococcus aureus from food sources was analyzed with respect to its morphology, genome sequence, and antibiotic resistance conversion ability. Phage TEM123 from a mitomycin C-induced lysate of S. aureus was isolated from foods. Morphological analysis under a transmission electron microscope revealed that it belonged to the family Siphoviridae. The genome of phage TEM123 consisted of a double-stranded DNA of 43,786 bp with a G+C content of 34.06%. A bioinformatics analysis of the phage genome identified 43 putative open reading frames (ORFs). ORF1 encoded a protein that was nearly identical to the metallo-β-lactamase enzymes that degrade β-lactam antibiotics. After transduction to S. aureus with phage TEM123, the metallo-β-lactamase gene was confirmed in the transductant by PCR and sequencing analyses. In a β-lactam antibiotic susceptibility test, the transductant was more highly resistant to β-lactam antibiotics than S. aureus S133. Phage TEM123 might play a role in the transfer of β-lactam antibiotic resistance determinants in S. aureus. Therefore, we suggest that the prophage of S. aureus with its exotoxin is a risk factor for food safety in the food chain through lateral gene transfer.

• 한국어병학회지
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• 제11권2호
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• pp.137-141
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• 1998

TSB 해수배지와 숙주로서 L. garvieae No. 44를 배양조건으로 사용한 경우, L. garvieae 111균주중 용원화되었다고 추정되어진 96균주의 cells에서 temperate Phage가 효과적으로 분리되었다. 하지만 동일한 배양조건에서 보통의 TSB 배지를 사용한 경우에서는 temperate phage는 전혀 나타나지 않았다. 이 temperate phages는 TSB 해수배지와 ultraviolet irradiation를 병용한 경우 역시 효과적으로 분리되었다. 분리된 모든 temperate Phages는 기존의 phage(PLgY, PLgW, PLgS) 의 lytic nature와는 달리 오직 L.garvieae No. 44만을 lysis하였다. 배양후 약 1시간후 phage가 나타났으며 12시간 후 virulent phage의 최고농도($10^{10}$ PFU/ml) 보다 훨씬 낮은 농도인 $10^6$ PFU/ml까지 증가하였다.

• 한국수산과학회지
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• 제28권2호
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• pp.209-218
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• 1995

본 연구에서는 유전자 복제기작을 생화학적, 분자생물학적 방법을 사용하여 bacteriphage T7을 대상으로 연구하였다. Bacteriophage T7의 유전자 복제, 재조합, 수선시 필수 단백질로 작용하는 gene 2.5 단백질의 생체내 기능에 대한 유전학적 연구와 단백질을 분리 정제하여 복제 단백질들과의 상호작용에 대한 연구를 수행하였다. 연구결과 gene 2.5 단백질은 DNA복제시 필수 구성단백질로 작용하며, 복제과정에서 유전자 복제에 관여하는 핵심 단백질들인 DNA polymerase, helicase/primase와 직접 단백질-단백질 상호 협동 작용을 하는 r것을 증명하였다. 특히 gene 2.5 단백질의 C-terminal domain이 절편된 변이체의 경우 복제 단백질들과 상호작용이 결여되었다. 따라서 C-terminal domain이 gene 2.5 단백질의 기능에 필수적으로 관여함을 입증하였다.

• 한국동물위생학회지
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• 제32권1호
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• pp.61-76
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• 2009

At the present study, it was aimed to explore the molecular genetic characterization of multiple antimicrobial resistant Salmonella spp. isolates from pigs and cattle. A total of 138 Salmonella Typhimurium (S. Typhimurium) isolates were typed with phage, among them, 83.3% of S. Typhimurium tested could divide into a 10 phage types. Definitive type 193 (DT193) (25.4%) and DT195 (24.6%) were exhibited as the dominant types. DT104 and U302 were found from pigs and cattle. On the other hand, S. Enteritidis had 6 phage types, of them, phage type 21 (PT21) and PT11b were the popular types. In the plasmid profiles, 135 of S. Typhimurium isolates were exhibited 1 to 6 plasmid bands which molecular weight ranged from 90 to 2kb. 35 isolates (25.4%) harbored a 90kb plasmid which is thought to be the serotype specific virulence plasmid. Two of twenty five S. Enteritidis had common plasmids at 2 and 1.5kb. With multiplex polymerase chain reaction, virulence genes (invA and spvC) were detected from all Salmonella spp. from 167 of S. Typhimurium, S. Enteritidis and chloramphenicol resistant S. Schwarzengrund, but some drug resistant genes, such as PSE-1, cml/tetR and flo were not determined but other drug resistant genes, for example TEM and int were found. The detection rates of spvC, TEM and int gene was 35.3%, 29.3% and 72.5%, respectively. The TEM gene was highly popular in S. Typhimurium, which was detected from ampicillin and amoxicillin resistant strains as 95.9%. int gene was able to detect from all the isolates identified as multidrug resistsnt (MDR), particularly DT193 was thought as the most prevalent virulence and multidrug resistance isolate. The major plasmid profile and drug resistance pattern of DT193 were 90, 40, 10.5, 6.3, 3.0kb and ACCbDNaPSSuT, respectively. MDR was commonly found in other phage types, particularly DT104, U302 and DT203.

• Journal of Microbiology and Biotechnology
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• 제31권10호
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• pp.1430-1437
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• 2021

Cronobacter sakazakii is an opportunistic pathogenic bacterium found in powdered infant formula and is fatal to neonates. Antibiotic resistance has emerged owing to overuse of antibiotics. Therefore, demand for high-yield bacteriophages as an alternative to antibiotics has increased. Accordingly, we developed a modified mass-production method for bacteriophages by introducing a two-stage self-cycling (TSSC) process, which yielded high-concentration bacteriophage solutions by replenishing the nutritional medium at the beginning of each process, without additional challenge. pH of the culture medium was monitored in real-time during C. sakazakii growth and bacteriophage CS01 propagation, and the changes in various parameters were assessed. The pH of the culture medium dropped to 5.8 when the host bacteria reached the early log phase (OD₅₄₀ = 0.3). After challenge, it decreased to 4.65 and then recovered to 4.94; therefore, we set the optimum pH to challenge the phage at 5.8 and that to harvest the phage at 4.94. We then compared phage production during the TSSC process in jar-type bioreactors and the batch culture process in shaker flasks. In the same volume of LB medium, the concentration of the phage titer solution obtained with the TSSC process was 24 times higher than that obtained with the batch culture process. Moreover, we stably obtained high concentrations of bacteriophage solutions for three cycles with the TSSC process. Overall, this modified TSSC process could simplify large-scale production of bacteriophage CS01 and reduce the unit cost of phage titer solution. These results could contribute to curing infants infected with antibiotic-resistant C. sakazakii.

• 대한수의학회지
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• 제40권3호
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• pp.515-524
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• 2000

The present study was conducted to investigate the phage types(PT) of Salmonella enteritidis(SE) isolated from animals and human patients in Korea during the period 1993-1999. SE were isolated from chickens including the layer and broiler, duck, rat, swine and human patients in nationwide scale. A total of 231 non-human and 14 human SE strains were phage typed and 80.4%(197/245) of SE isolates tested could discriminate as a ten SEPTs including the RDNC by the 10 standard phages, which were brought from the Central Public Health Laboratory in England. In analysing of phage types both animal and human SE isolates, SEPT 4(55.4%) was the most prevalent in domestic animals including the layer(39.3%) and broiler(64.5%), duck(55.5%), and swine(75.0%) since 1993. About 57% of the S enteritidis from human was SEPT 4. Along with SEPT 4, SEPT 1, SEPT 6a, SEPT 7 and SEPT 7a var, SEPT 9b, SEPT 15, SEPT 21b and SEPT 22 were also found from animal and human SE isolates. SEPT 4(40.0%) was isolated from frozen chicken meats imported from China along with SEPT 7 and 7a var strains in this study. In conclusion, SEPT 4 was the most predominant SEPT in our country regardless of animal or human hosts including the Che-Ju island and almost exclusively found in domestic poultry(layer and broiler). During the review period, SEPT 4 has already been spreading continually among the animal hosts since 1993.

• 한국동물위생학회지
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• 제34권3호
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• pp.217-226
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• 2011

Salmonella spp. is of increasing public health concern as causative pathogens of food poisoning. The aim of this study was to investigate the serotypes and antimicrobial resistance pattern of Salmonella spp. isolated from duck farms in Daegu-Gyeongbuk province. Also, S. Enteritidis and S. Typhimurium isolates were further examined for plasmid analysis, phage typing and pulsed-field gel electrophoresis (PFGE). A total of 34 Salmonella spp. (16.4%) were isolated from duck farms and ten serotypes were identified. The predominant serotypes were S. Typhimurium (23.5%) S. Fyris (17.6%) and S. Haardt (11.8%), S. Agona and S. Enteritidis (respectively 8.8%). Of 34 Salmonella isolates, 15 (44.1%) isolates were resistant to at least one antimicrobial agent and multiple resistance (resistance to more than 4 drugs) was observed in 9 strains (26.5%). The high resistance was found to streptomycin (32.4%), tetracycline (29.4%), ampicillin, kanamycin and nalidixic acid (respectively, 26.5%), all Salmonella isolates were susceptible to cefoxitin, cefotaxime, gentamicin, amikacin and ciprofloxacin. All S. Enteritidis and S. Typhimurium isolates were found to contain only one plasmid (ca. 54 or 55kb, respectively). Among the S. Enteritidis isolates, two phage types were found, PT32a and PT1c, respectively, one isolates did not react with any of the phages used. Whereas, all S. Typhimurium isolates were RDNC (reacts but does not conform). PFGE showed to be a useful typing method better than plasmid analysis and phage typing for discrimination of isolates especially, S. Typhimurium isolates. Our results indicated that the serotypes of Salmonella isolates are widely distributed in duck farms, further epidemiological studies should be carried out.

• 약학회지
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• 제47권3호
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• pp.176-179
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• 2003

A library of unlimited number of novel lectins with diverse specificities has been previously generated by randomly mutating the carbohydrate-recognition domain of Maackia amurensis hemagglutinin (MAH). To establish the experimental environment capable of selecting high affinity mutant lectins in E. coli, phage display system was adapted. Carbohydrate binding capacity of two phagemid vectors, pComb3 and pComb8 displaying wild-type MAH lectin was assessed. Specific bindings of pComb3 and pComb8 phages expressing w.t. MAH to affinity-purified polyclonal anti-MAH antibody and to glycophorin was demonstrated. Both phages also showed strong hemagglutinating activity to intact but not sialidase-treated human erythrocytes, which is consistent to the specificity of native MAH. Taken together, two different phage display vectors successfully allowed the expression of active MAH as a fusion protein on the surface of bacteriophage, which will lead to preparation of unique plant lectins with high affinity toward a variety of carbohydrate chains.

• 미생물학회지
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• 제25권3호
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• pp.184-188
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• 1987

Evidences that the mannose permease of Escherichia coli mediates the infection of N4 in early steps, were obtained as follows. First, A mutant strain of Escherichia coli which was resistant to both wild type N4 and lambda whose genome is Charon 4A containing human genomic fragments in its EcoR I site, could not use mannose efficiently. Second, N4 could not infect pel mutant strains which lack one or all of intact components of mannose permease. However, unknown alterations in N4 made it possible for the phage to infect pel mutant of E. coli. It also turned out to be clear that the receptor of N4 was different from that of lambda.

• Journal of Microbiology
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• 제44권5호
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• pp.530-536
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• 2006

Bacteriophage P4, a satellite phage of coliphage P2, is a very useful experimental tool for the study of viral capsid assembly and cos-cleavage. For an in vitro cos-cleavage reaction study of the P2-P4 system, new shortened and selectable markers containing P4 derivative plasm ids were designed as a substrate molecules. They were constructed by swapping the non-essential segment of P4 DNA for either the kanamycin resistance (kmr) gene or the ampicillin resistance (apr) gene. The size of the genomes of the resulting markers were 82% (P4 ash8 delRI:: kmr) and 79% (P4 ash8 delRI:: apr) of the wild type P4 genome. To determine the lower limit of genome size that could be packaged into the small P4-size bead, these shortened P4 plasmids were converted to phage particles with infection of the helper phage P2. The conversion of plasmid P4 derivatives to bacteriophage particles was verified by the heat stability test and the burst size determination experiment. CsCl buoyant equilibrium density gradient experiments confirmed not only the genome size of the viable phage form of shortened P4 derivatives, but also their packaging into the small P4-size head. P4 ash8 delRI:: apr turned out to be the smallest P4 genome that can be packaged into P4-sized head.