• 한국축산식품학회지
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• 제40권5호
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• pp.746-757
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• 2020

Enterotoxigenic Escherichia coli (ETEC) is the major pathogenic E. coli that causes diarrhea and edema in post-weaning piglets. In this study, we describe the morphology and characteristics of ØCJ19, a bacteriophage that infects ETEC, and performed genetic analysis. Phage ØCJ19 belongs to the family Myoviridae. One-step growth curve showed a latent phase of 5 min and burst size of approximately 20 phage particles/infected cell. Phage infectivity was stable for 2 h between 4℃ and 55℃, and the phage was stable between pH 3 and 11. Genetic analysis revealed that phage ØCJ19 has a total of 49,567 bases and 79 open reading frames (ORFs). The full genomic sequence of phage ØCJ19 showed the most similarity to an Escherichia phage, vB_EcoS_ESCO41. There were no genes encoding lysogeny, toxins, virulence factors, or antibiotic resistance in this phage, suggesting that this phage can be used safely as a biological agent to control ETEC. Comparative genomic analysis in terms of the tail fiber proteins could provide genetic insight into host recognition and the relationship with other coliphages. These results showed the possibility to improve food safety by applying phage ØCJ19 to foods of animal origin contaminated with ETEC and suggests that it could be the basis for establishing a safety management system in the animal husbandry.

• Journal of Microbiology and Biotechnology
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• 제26권1호
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• pp.160-170
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• 2016

The increasing spread of antibiotic-resistant pathogens has raised the interest in alternative antimicrobial treatments. In our study, the functionally active gram-negative bacterium bacteriophage CP933 endolysin was produced in Nicotiana benthamiana plants by a combination of transient expression and vacuole targeting strategies, and its antimicrobial activity was investigated. Expression of the cp933 gene in E. coli led to growth inhibition and lysis of the host cells or production of trace amounts of CP933. Cytoplasmic expression of the cp933 gene in plants using Potato virus X-based transient expression vectors (pP2C2S and pGR107) resulted in death of the apical portion of experimental plants. To protect plants against the toxic effects of the CP933 protein, the cp933 coding region was fused at its Nterminus to an N-terminal signal peptide from the potato proteinase inhibitor I to direct CP933 to the delta-type vacuoles. Plants producing the CP933 fusion protein did not exhibit the severe toxic effects seen with the unfused protein and the level of expression was 0.16 mg/g of plant tissue. Antimicrobial assays revealed that, in contrast to gram-negative bacterium E. coli (BL21(DE3)), the gram-positive plant pathogenic bacterium Clavibacter michiganensis was more susceptible to the plant-produced CP933, showing 18% growth inhibition. The results of our experiments demonstrate that the combination of transient expression and protein targeting to the delta vacuoles is a promising approach to produce functionally active proteins that exhibit toxicity when expressed in plant cells.

• 한국식품위생안전성학회지
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• 제35권2호
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• pp.189-194
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• 2020

본 연구는 항생제 내성 Salmonella Typhimurium CCARM 8009을 저해하기 위한 phage와 항생제 조합처리의 효과를 평가하였다. 디스크 확산법과 액체배지 희석법에 의해 phage와 항생제의 상승 저해효과를 측정하였고 배양을 통한 항생제 내성 유도를 평가하였다. Phage를 처리한 cefotaxime, chloramphenicol, ciprofloxacin, erythromycin의 디스크의 저해 구역은 각각 13.6%, 19.3%, 12.7%, 78.8%로 증가되었다. Phage와 항생제 조합 처리에 의해 tetracycline, chloramphenicol, ciprofloxacin, erythromycin, streptomycin의 최소생육억제농도는 각각 64, 4, 0.0078, 64, 256 mg/mL으로 감소되었다. Phage와 항생제의 조합 처리는 항생제 내성 S. Typhimurium CCARM 8009을 효과적으로 저해하였다 (4 log reduction). 본 결과는 phage와 항생제의 조합처리는 항생제 내성균을 제어하기 위한 방법으로 충분히 응용가치가 높음을 보여주고 있다.

• Journal of Applied Biological Chemistry
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• 제62권3호
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• pp.287-292
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• 2019

Pseudomonas tolaasii는 느타리버섯에 갈반병을 일으키는 병원균주로, 다양한 변이균주들을 분리하여 $P1{\alpha}$와 $P1{\beta}$, $P1{\gamma}$ 세 가지 소그룹으로 분류하였다. 각 그룹별 균주들에 특이적인 박테리오파지를 이용한 파지테라피는 갈반병 방제에 매우 성공적이었다. 본 연구에서는, 박테리오파지들의 특성을 구명하기 위하여 소그룹별 대표균주을 이용하여 파지를 분리하였고, 이들의 다클론항체를 제작하여 파지들 사이에 유연관계를 조사하였다. 파지 준비물은 $10^{10}pfu/mL$ 이상으로 토끼의 다리 근육에 주사하였고, 3회의 반복주사에 의해 다클론항체가 얻어졌다. 파지 ${\phi}6264$에 대한 항체의 역가는 $2{\times}10^7Ab/mL$ 이상, 파지 ${\phi}HK2$에 대해서는 $1{\times}10^6Ab/mL$, 파지 ${\phi}HK19$와 ${\phi}HK23$에 대해서는 $1{\times}10^7Ab/mL$ 이상이었다. 항체와 이에 특이적인 파지 사이에는 매우 높은 반응특이성이 있었고, 소그룹이 다른 파지의 항체와 파지 사이에도 일부 교차반응성을 확인하였다. 파지 ${\phi}6264$에서 생성된 $Ab{\phi}6264$는 모든 $P1{\alpha}$ 소그룹의 파지들과 반응성을 보였으나, 파지 ${\phi}HK16$을 제외한 다른 소그룹의 파지들과는 반응하지 않았다. $P1{\gamma}$ 소그룹에서 생성된 $Ab{\phi}HK23$은 $P1{\beta}$ 소그룹의 모든 파지들을 불활성화시켜 가장 넓은 항체범위를 보였다. 항체와 파지를 이용한 숙주균과의 관계를 분석하였을 때, 16S rRNA 유전자 분석에 의한 숙주균의 근연관계와 항체를 이용한 숙주균의 파지들 사이의 구조적 근연관계는 상당히 차이가 있음을 확인하였다. 결론적으로, 박테리오파지의 숙주균 특이성과 항체를 이용해 측정한 파지의 껍질단백질 구조유사성 사이에는 약한 상관성을 보였다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.584-587
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• 2000

The invasion genes from Salmonella typhimurium were identified by the construction of a cosmid library and subcloning genes into a plasmid vector, pGEM-7Z. The 4.65 kb fragment of the invasion-conferring genomic region of the subclone, pSV6235 was sequenced in both direction. The three open reading frames, which were located at downstream of a promoter region, were designated as sir (Salmonella invasion region)A coding for the 36 amino acids, sirB coding for the 132 amino acids and sirC for the 82 amino acids, respectively. Interesingly, the genomic region of pSV6235 was highly homologous to Yersinia enterocolitica genomic DNA for a high pathogenicity island and Salmonella enteritidis insertion element IS1351 and IS200 DNA. These results show that there could be a significant relationship between S. typhimurium, Y. enterocolitica and S. enteritidis with respect to horizontal evolution process and acquisition of virulence determinants by means of transposon, plasmid or bacteriophage.

• Journal of Microbiology and Biotechnology
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• 제29권12호
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• pp.1916-1924
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• 2019

Outbreaks of staphylococcal food poisoning (SFP) causing serious human diseases and economic losses have been reported globally. Furthermore, the spread of Staphylococcus aureus with increased resistance to multiple antimicrobial agents has become a major concern in the food industries and medicine. Here, we isolated an endolysin LysSAP8, as one of the peptidoglycan hydrolases, derived from the bacteriophage SAP8 infecting S. aureus. This endolysin was tagged with a 6×His at the C-terminal of the target protein and purified using affinity chromatography. LysSAP8 demonstrated lytic activity against a broad spectrum of bacteria, which included a majority of the staphylococcal strains tested in this study as well as the methicillin-resistant S. aureus (MRSA); however, no such activity was observed against other gram-positive or gram-negative bacteria. Additionally, LysSAP8 could maintain bactericidal activity until 0.1 nM working concentration and after heat treatment at 37℃ for 30 min. The ability of LysSAP8 to lyse cells under varying conditions of temperature (4-43℃), pH (3-9), and NaCl concentrations (0-1,000 mM), and divalent metal ions (Ca²⁺, Co²⁺, Cu²⁺, Mg²⁺, Mn²⁺, Hg²⁺, and Zn²⁺) was examined. At the optimized condition, LysSAP8 could disrupt approximately 3.46 log CFU/ml of the planktonic cells in their exponential phase of growth within 30 min. In this study, we have suggested that LysSAP8 could be a potent alternative as a biocontrol agent that can be used to combat MRSA.

• Food Science and Biotechnology
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• 제16권3호
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• pp.398-403
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• 2007

The effectiveness of phage biocontrol depends on the activity of bacteriophage in a given environment. In order to investigate the infectivity and the stability of bacteriophages in representative environments, three virulent phages, Listeria phage A511, Salmonella phage Felix O1, and Escherichia coli phage T7, were subjected to different temperatures, pHs and salt concentrations (NaCl). Phage infectivity was also determined in the presence of divalent cations ($Mg^{2+}$ or $Ca^{2+}$). As a result, three phages exhibited a wide range of survival rates under various environments. Phage infectivity was directly correlated with bacterial growth under the applied conditions. One exception was Felix O1 that did not kill Salmonella grown in low pH (4.5). The failure was attributed to defective adsorption of Felix O1. This finding is significant as it provides an explanation for the inefficient phage biocontrol. Therefore, such information is crucial to improve phage biocontrol of pathogens.

• The Plant Pathology Journal
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• 제40권2호
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• pp.160-170
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• 2024

Erwinia amylovora is a plant pathogen that causes fire blight on apples and pears. Bacteriophages, which are viruses that selectively infect specific species of bacteria and are harmless to animal cells, have been considered as biological control agents for the prevention of bacterial pathogens. In this study, we aimed to use bacteriophages that infect E. amylovora as biocontrol agents against fire blight. We isolated bacteriophages Fifi044 and Fifi318 infecting E. amylovora, and characterized their morphology, plaque form, and genetic diversity to use as cocktails for disease control. The stabilities of the two phages were investigated at various temperatures and pH values and under sunlight, and long-term storage experiment was conducted for a year. To evaluate whether the two phages were suitable for use in cocktail form, growth curves of E. amylovora were prepared after treating the bacterial cells with single phages and a phage cocktail. In addition, a disease control test was conducted using immature apples and in vitro cultured apple plantlets to determine the biocontrol effects of the phage cocktail. The two phages were morphologically and genetically different, and highly stable up to 50℃ and pH value from 4 to 10. The phages showed synergistic effect when used as a cocktail in the inhibition of host bacterial growth and the disease control. This study demonstrated that the potential of the phage cocktail as a biocontrol agent for commercial use.

• 미생물학회지
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• 제23권1호
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• pp.9-12
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• 1985

증폭된 재조합 trp operon의 발현을 위한 숙주박테리아 개발의 일환으로 숙수 E. coli에 $aroP^{-}$ 변이를 도입하였다. $aroP^{-}$ 변이의 유도에는 trans po son Tn10을 사용하였으며 P1Kc파아지를 이용하여 숙주박테리아에 형질도입하였다. General aromatic amino acid transport system이 결여된 $aroP^{-}$ 변이주는 $\beta$-thienylalanine ($(2{\times}10^{-4}M)$). p-fluor-phenylalanine ($(2{\times}10^{-4}M)$) 그리고 5-methyltryptophan에 저항성을 가졌다. $aroP^{-}$ 변이주는 $aroP^{-}$ 야생주에 비해서 〔$[^3H]$-tryptophan uptake가 상당히 감소하였다. 또한 NaN, ($(2{\times}10^{-4}M)$)를 처리하였을 때의 ($[^3H]$)-tryptophan uptake 비율은 aroP 변이주가 $aroP^{-}$야생주보다 덜 감소하였다. E. coli $trpR^{-ts}/ColE_1 -trp^+$ 균주에 aroP 형질을 도입하였을 때 트립토판 방출이 $aroP^{-}$ 야생주에 비해서 4 배나 증가하였다.

• Journal of Microbiology and Biotechnology
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• 제5권1호
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• pp.14-17
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• 1995

Endoglucanase gene of Pseudomonas sp. LBC505 was previously cloned in pUC19 to yield plasmid pLCl. The Pseudomonas sp. LBC505 endoglucanase gene was subcloned in a temperature-regulated Es-cherichia coli expression vector, pAS1, containing the leftward promoter $P_L$ of bacteriophage lambda. The level of gene expression was controlled by the thermal inactivation of the heat-sensitive lambda cI857 repressor. Best yield of endoglucanase was obtained by lowering the incubation temperature to $37^{\circ}C$ after induction at $42^{\circ}C$ for 1h. Under these conditions enzyme production continued for about 5h at a gradually decreasing rate. Ecoli harboring recombinant plasmid pASC10 expressed 4.3 times as much CMCase activity as E.coli containing pLCl. To enhance the expression level of endogl, ucanase gene, we have also changed the presumptive Shine-Dalgamo sequence (AGAGGT) of the gene to consensus sequence (AGGAGGT) by site-directed mutagenesis. The genes mutated were subcloned in pASl resulting in the formation of recombinant plasmid pASS50. E.coli harboring the plasmid pASS50 expressed 6.2-fold higher levels of CMCase activity than that of E.coli harboring pLC1.