• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.663-667
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• 2005

Water-soluble glucan was produced by mutants of E. coli BL21(DE)/CrdS-F and E. coli BL21(DE)/CrdS-C in a fermentor. Mutants of E. coli BL21(DE)/CrdS-F which has putative ${\beta}-1,3-glucan$ synthase catalytic subunit (gi:40556679) gene and E. coli BL21(DE)/CrdS-C which contains the active catalytic domain of partial curdlan synthase gene. The molecular weight of water-soluble glucan was analysed with HPLC.

• Korean Journal of Microbiology
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• v.27 no.2
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• pp.92-97
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• 1989

the vector, pGUR19, for Rhizobium gene manipulation, was constructed by combining the replication and mobilization function of indigenous multicopy plasmid from Acacia(Robinia pseudoacacia L.) Rhizobia sp86 with E. coli cloning vehicle, pBR322. The vector could be efficiently mobilized by RP4 tra function incorporated into chromosome of E. coli named SM10 and efficiently transferred to various gram negative hosts including Rhizobium and Afrobacterium by transformation. Mobilization frequency of the constructed vector was ranged from $1.2\times 10^{-2}$ (E.coli HB 101) to $4.6\times 10^{-4}$ (A. tumefaciens 15955) and transformation frequency was ranged from $5.4\times 10^{-7}$(E. coli HB101) to $1.2\times 10^{-10}$ (A. tumefaciens 15955). The vector, pGUR19, was stably replicated and maintained in a variety of Rhizobium and Agrobacterium.

• The Journal of the Korean Society for Microbiology
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• v.21 no.4
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• pp.417-422
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• 1986

The specimens were collected from 89 diarrheal patients who had visited Pusan National University Hospital from June to September 1985. They were cultured and tested for the bacteriological identification of causative agents. In this study we identified 5 strains of Salmonella species, 5 strains of Shigella species, 2 strains of Y. enterocolitica, and 17 strains of enteric pathogenic E. coli. Enteric pathogenic E. coli were classified into enterotoxigenic E. coli, enteropathogenic E. coli, and enteroinvasive E. coli by serological type. We tried to isolate V. cholerae and V. parahaemolyticus too but we cannot find them out.

• Korean Journal of Veterinary Service
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• v.16 no.1
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• pp.76-81
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• 1993

To evaluate the pathogenesis of live infectious laryngotracheitis vaccine, virus, virus and E.coli were inoculated in 4-weeks old intraorbitally and intraorally. Their pathology and serology were studied. The results were as follows. 1. thicks Inoculated with ILT vaccine alone showed no clinical sign. 2. Some of chicks inoculated with ILT vaccine followed by E.coli after 1day showed nasal discharge and cough. 3. Some of chicks inoculated with E. coli followed by ILT vaccine after 1 day and inoculated ILT vaccine and E.coli concurrently, showed nasal discharge. 4. Serum neutralization titers of chicks inoculated with ILT vaccine increased 3 weeks after Inoculation, peaked at 7 to 8 weeks and decreased. 5. Antibiotic sensitivity of E.coli were higher in Enrofloxacin (Baytril) and chloramphenical.

• Microbiology and Biotechnology Letters
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• v.19 no.5
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• pp.491-496
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• 1991

To maximize the production of aminoglycoside-3'-phosphotransferase of E. coli ATCC 21990 carrying R factor which encodes aminoglycoside-3'-phosphotransferase (APH(3')) phosphorylating the 3'-hydroxyl group of aminoglycoside, mutants M1 and M2, media composition and several factors affecting the enzyme production during fermentation were studied. Although the specific activity of APH(3') produced by a mutant M1 was increased as much as four times than that of E. coii ATCC 21990, the growth rate was decreased. The increase of the enzyme production was obtained by increased biomass during fermentation. A mutant M2 was obtained to increase the cell growth rate. Mutant M2 cells were cultivated with optimal media and pure oxygen gas in a fed-batch mode of fermentor operation. The specific activity of APH(3') was decreased, but total enzyme activity of APH(3') was increased as much as two point five times than that of mutant MI.

• Journal of Food Hygiene and Safety
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• v.32 no.2
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• pp.147-153
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• 2017

The purpose of this study was to isolate Escherichia coli from flies and to assess pathogenic genes and antibiotic resistance of the isolates. A total of 188 flies were captured in agricultural environment including fruits farms (n = 19), fermented soybean farms (n = 9), municipal waste (n = 46), livestock farms (n = 66), slaughterhouses (n = 38), and manure ground (n = 10). E. coli isolates of captured flies were tested for pathogenic gene and antibiotic resistance using PCR methods and VITEK2 systems. As a result, E. coli from 63% (119/188) of the captured flies has been detected, and the detection rate of E. coli was the highest (89%, 31/34) in flies captured at particular slaughterhouse. Of the 34 isolates, 94% (32/34) were pathogenic gene (ST gene) positive. Twenty-six percent (31/119) of the E. coli isolates were observed being resistant to one or more antibiotics. Markedly, one of E. coli isolates from Livestock farms was resistant to 7 antibiotics including ampicillin, ampicillin/sulbactam, cefazolin, cefotaxime, gentamicin, levofloxacin, and trimethoprim/sulfamethoxazole. In addition, it was ESBL positive. The results of the present study may suggest a risk of transmission of pathogenic and antimicrobial resistant bacteria from flies to livestock environment Therefore, it may need to prevent introducing flies into the agricultural production environment for safe food production.

• Korean Journal of Microbiology
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• v.32 no.1
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• pp.47-52
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• 1994

The cells of Campylobacter jejuni heat-shocked at 48${\circ}C$ for 30 min synthesized the heat shock proteins of HSP90, HSP66 and HSP60. Those heat shock proteins were found to correspond to the heat shock proteins of HSP87, HSP66 (DnaK), and HSP58 (GroEL) of E. coli, respectively. By Southern blot analysis of the chromosomal DNAs of C. jejuni with groESL and dnaK genes of E. coli as DNA probes, the heat shock genes of C. jejuni which are homologous to the E. coli groESL and dnaK genes were found to exist in the chromosomal DNA. The genomic libraries of C. jejuni were constructed with the cosmid vector pWE15 and the groEL gene of C. jejuni were cloned in E. coli B178 groEL44 temperature senstive mutant. The hybrid plasmid (pLC1) was inserted with the DNA fragment (about 5.7kb in size) containing the groEL gene. E. coli groEL44 mutant cell transformed with the pLC1 could grow at 42${\circ}C$ by synthesizing the HSP60 of C. jejuni and regained the susceptibility to the ${\lambda}$ vir phage by expression of the groEL gene in the cloned cells. These indicated that the groEL products of C. jejuni had chaperon effects by synthesizing the heat shock proteins in the cloned cells of E. coli.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.3
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• pp.571-575
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• 2004

Escherichia coli O157:H7 cause hemorrhagic colitis and the extraintestinal complication of hemolytic-uremic syndrome, with their higher incidence occurring in children. Lipopolysaccharide (LPS) of E. coli O157:H7 is very important to make IgG anti-LPS with bactericidal activity. To identify the characteristic of E. coli OI57:H7, we isolated 60 MDa plasmid and amplified stx genes of shiga-like toxin (Stx) 1, 2 of E. coli O157:H7 by polymerase chain reaction (PCR) method. Using the simple purification method which contained phenol extract, ethanol precipitation and gel filtration steps, the LPS of E. coli O157:H7 was isolated and purified. Finally, we confirmed the purity of LPS through SDS-PAGE and silver nitrate staining.

• Korean Journal of Microbiology
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• v.32 no.1
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• pp.40-46
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• 1994

The pcb genes of Pseudomonas sp. DJ-12 coded for the catabolism of polychlorinated biphenyl (PCBs) and biphenyl. The products of the pcbCD genes were 2,3-dihydroxy-4'-chlorobiphenyl dioxygenase and meta-cleavage product (MCP) hydrolase, which acted on degradation of 2,3-dihydroxy-4'-chlorobiphenyl to 4-chlorobenzoate. The pcbCD genes were cloned in E. coli XLl-Blue, and then the pcbD gene was further subcloned. As a metabolite transformed from 2,3-dihydroxybiphenyl by the cloned cell of E coli CU103, benzoate was detected by the resting cell assay. The enzyme activities of 2,3-dihydroxybiphenyl dioxygease and MCP hydrolase produced in the cloned cells E. coli CU103 and CU105 were about 17 and 3 times higher than those of Pseudomonas sp. DJ-12, respectively.

• Food Quality and Culture
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• v.2 no.1
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• pp.55-60
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• 2008

This study examined the effects of lactic acid spray, hot water spray, or their combined treatment, as well as the effects of acidified sodium chlorite (ASC), for the decontamination of Escherichia coli on beef carcass surfaces using a commercial intervention system. With this system, the effects of 2 or 4% lactic acid (v/v), hot water ($89{\pm}1^{\circ}C$), or their combined treatment, were examined in terms of reducing inoculated E. coli. ASC (266 ppm), which was adjusted to pH 2.5 using acetic acid or citric acid, was applied using a hand-held spray system. When the beef carcasses were treated with 2 or 4% lactic acid for 10.4 s, less than 1 log reductions of inoculated E. coli were observed. A hot water spray treatment for 9.8 s resulted in a 2.1 log reduction of inoculated E. coli. However, when the hot water was followed with either 2 or 4% lactic acid, no difference in E. coli reduction was found between the hot water alone or the combined treatment with lactic acid. When ASC was adjusted to pH 2.5 with acetic acid and citric acid, 3.8 and 4.1 log reductions of E. coli were observed, respectively. Overall, the lactic acid spray treatment was least effective, and the ASC treatment was most effective, for the E. coli decontamination of beef carcasses. Therefore, these data suggest that ASC would be a more effective intervention against E. coli than most of the methods currently being used. However, more research is required to evaluate the effects of ASC on other organisms, as well as to identify application methods that will not affect meat quality.