• Microbiology and Biotechnology Letters
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• v.16 no.4
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• pp.316-319
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• 1988

Pectate Lyase (PL) was cloned from alkali-tolerant Bacillus sp. YA-14 into Escherichia coli MB1000 by inserting HindIII-generated DNA fragment into the HindIII site of pBR322 and then screening recombinant transformant for the ability to hydrolyze sodium polypectate on agar plate, The recombinant plasmid, called pYPC29, was isolated, and the size of the cloned HindIII fragment was found to be 1.6 kb. The PL gene was stablely maintained and expressed efficiently in Escherichia coli. The Pt accumulated largely in the periplasmic space of Escherichia coli clones.

• Korean Journal of Veterinary Research
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• v.39 no.4
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• pp.765-771
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• 1999

Unlike most Escherichia coli strains, E coli O157 : H7 didn't ferment sorbitol within 24h of incubation and showed a negative reaction for $\beta$-glucuronidase. We developed a new medium for the rapid isolation of E coli O157 : H7 using sorbitol MacConkey agar with cefixime, potassium tellurite and 4-methylumbelliferyl-${\beta}$-D-glucuronide (MUG) as a primary plating medium. The addition of $20{\mu}g/ml$ of vancomycin in enrichment broth for E coli O157 : H7 inhibited lots of Gram positive bacteria. Three strains (10.3%) of 29 non-O157 E coli strains and 3 strains (8.3%) of 36 Salmonella spp were inhibited at the $0.05{\mu}g/ml$ of cefixime and 23 strains (79.3%) of 29 non-O157 E coli strains and 12 strains (33.3%) of 36 Salmonella spp were inhibited at the $2.0{\mu}g/ml$ of potassium tellurite. But none of the E coli O157 : H7 was affected at these concentration. The addition of MUG at $100{\mu}g/ml$ level to sorbitol MacConkey agar with cefixime and potassium tellurite (CTM-SMAC) aided in the rapid isolation of E coli O157 : H7 from samples by checking sorbitol-negative and $\beta$-glucuronidase negative phenotypes simultaneously. In conclusion, inoculation of a positive in the O157 screening test from enrichment broth on CTM-SMAC appeared to be a rapid, cost-effective and sensitive method for the isolation of E coli O157 : H7.

• Journal of Veterinary Clinics
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• v.24 no.4
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• pp.636-639
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• 2007

Septicemic polyserositis and navel ill associated with Escherichia coli were reported in a 14-day-old male thoroughbred foal. The horse died after showing 12-day history of anorexia, lethargy, lameness and endophthalmus. Grossly, milky yellow abscesses were occupied in umbilicus, umbilical vein and artery. Large amounts of turbid pale yellow fluids were seen in pericardial sac, thoracic and abdominal cavity. Yellowish fibrinous materials were also presented in thoracic and abdominal cavity. Sticky pale yellow fluid and fibrinous materials were filled in stifle joint cavities of both hind limbs. Histologically, fibrino-purulent polyserositis and arthritis were observed. Severe omphalophlebitis with intra-lesional Gram negative bacterial colonies were noted in umbilical vein. Most of mesothelial cells in serosal cavities were severely hypertrophied. Pathogenic E. coli was purely isolated from ascites, thoracic and synovial fluids. Based on the results, the septicemic polyserositis may be originated from the umbilical cord infected with E. coli in this foal.

• Journal of Food Hygiene and Safety
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• v.12 no.4
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• pp.304-309
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• 1997

A study was undertaken to determine the thermal inactivation of Escherichia coli O157:H7 as influenced by the effects of temperature, time, suspension medium and ascorbate. Tryptic soy broth was more heat resistant than pfosphate buffer (pH 7.1), with D values of 1.52~1.68 min at 6$0^{\circ}C$ and 1.51~1.63 min at 7$0^{\circ}C$ compared with 1.52~1.65 min at 6$0^{\circ}C$ and 1.26~1.61 min at 7$0^{\circ}C$ for phosphate buffer as suspension medium. E. coli O157:H7 was completely inhibited within 30 min when small inoculum (106 CFU/$m\ell$) was heated at 7$0^{\circ}C$. When E. coli O157:H7 was preheated at 48$^{\circ}C$ for 60 min in phosphate buffer before heating, D values were 1.28~1.60 min at 6$0^{\circ}C$, and 1.13~1.56 min at 7$0^{\circ}C$, showing that preheating increases the heat resistance of the strain. Phosphate buffer containing ascorbate (0.001 M) was enhanced the thermal inactivation of the strain when inoculated as large inoculum (109 CFU/$m\ell$), while ascorbic acid was no effect at low cell concentrations (109 CFU/$m\ell$).

• Korean Journal of Veterinary Research
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• v.36 no.2
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• pp.371-378
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• 1996

Three and 2 strains of E coli O157 were isolated from fecal materials of cattle (390) and pigs (420) in Korea, respectively. One strain of O157:H7 isolated from cattle and 2 strains of O157:H7 isolated from pigs were identified as verotoxin-1 (VT-1) produing strains and 2 strains (O157:H7 and O157:H-) isolated from cattle were identified as verotoxin-2 (VT-2) producing strains by neutralization test on HeLa and Vero cells. Culture supernatants of the isolates were cytotoxic to HeLa and Vero cells. The levels of cytotoxin produced by isolates were $10^2{\sim}10^4$ cytotoxic dose($CD_{50}$)/ml. Also, VT-2-converting bacteriophage was isolated from KSC109 strain which had been isolated from cattle. Molecular weight of the phage DNA was determined as approximately 45 Kb in 0.8% agarose gel electrophoresis, and morphology of the phage stained with phosphotungstic acid was observed by transmissible electron microscopy.

• Journal of Electrical Engineering and Technology
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• v.6 no.2
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• pp.275-279
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• 2011

Sterilization of Escherichia coli (E. coli) is examined using a unique pulsed ultra-violet (UV) elliptical reactor based on Nd:YAG laser resonator, UV radiation from a pulsed xenon flashlamp. The light from the discharge has a broadband emission spectrum extending from the UV to the infrared region with a rich UV contained. Sterilization method by using the UV light is fast, environment-friendly and it does not cause secondary pollution. A Nd:YAG laser resonator having elliptical shape has advantage of concentrating the radiation of the UV light at two foci as the quart sleeve filled with E. coli. The primary objective of this research is to determine the important parameters such as pulse per second (pps), the applied voltage for sterilizing E. coli by using an UV elliptical reactor. From the experiment result, the sterilization effect of UV elliptical reactor is better than that of UV cylindrical reactor, and it can be 99.9% of sterilization at 800V regardless of the pps within 10 minutes.

• Journal of Microbiology and Biotechnology
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• v.17 no.3
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• pp.474-480
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• 2007

Fusarium wilt of cucumbers was effectively controlled by Escherichia coli expressing an endochitinase gene (chiA), and the rate was as effective (60.0%) as the wild-type strain S. proteamaculans 3095 (55.0%) where the gene was cloned. However, live cells of soil inoculated E. coli host harboring the chiA gene did not proliferate but declined 100-fold from $10^8$ CFU during the first week and showed less than 10 cells after day 14, suggesting that E. coli was able to express and produce the chitinase enzyme to the soil even as the population was gradually decreasing. Because the majority of the strains was alive for only a short period of time and the Fusarium-affected seedlings showed symptoms of wilting within 7-10 days, it seems that the pathogen control was decided early after the introduction of the biocontrol agent, eliminating the survival of the antagonist. These results indicated that soil inoculated E. coli could sufficiently express and produce the recombinant protein to control the pathogen, and root or soil colonization of the antagonist might not be a significant factor in determining the efficacy of biological control.

• Fisheries and Aquatic Sciences
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• v.14 no.3
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• pp.226-229
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• 2011

This study was conducted to develop a proficiency test (PT) specimen for the enumeration of Escherichia coli, a sanitary indicative bacterium, in molluscan bivalve shellfish. The common mussel Mytilus edulis was chosen as a matrix for the PT specimen. Mussels were artificially bioaccumulated for approximately 3 h with E. coli culture. After determining the homogeneity of samples, samples were distributed to 17 participants involved in the proficiency testing program. The enumeration of E. coli was performed by the most probable number method of the American Public Health Association. Statistical evaluations of the results obtained from inter- and intra-laboratory variation indicated no significant differences in the accuracy of these techniques between participants, indicating z-scores of ${\leq}{\pm}2$ and suggesting that preparation of the PT specimen for enumerating E coli in shellfish was successful.

• Archives of Pharmacal Research
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• v.21 no.3
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• pp.305-309
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• 1998

Human cytochrome P450 1A2 is one of the major cytochrome P450s in human liver. It is known to be capable of activating a number of carcinogens such as arylamines and heterocyclic amines. In order to develop the new bacterial mutagenicity test system with human P450, a full length of human P450 1A2 cDNA inserted into pCW bacterial expression vector was introduced to Escherichia coli WP2 uvrA strain which is a well-known E. coli strain for bacterial reverse mutagenicity assay. Expressed human P450 1A2 showed typical P450 hemoprotein spectra. Maximum expression was achieved at 48 hrs after incubating at $30^{\circ}C$ in terrific broth containing ampicillin, IPTG and other supplements. High level expression of P450 1A2 in E. coli WP2 uvrA membranes was determined in SDS-PAGE. The well-known mutagens 2-aminoanthracene and MElQ increased the revertant colonies of E. coli WP2 uvrA expressing human P450 1A2 without an exogenous rat hepatic post-mitochondrial supernatant (S9 fraction) in a dose-dependent manner. The results show that the functional expression of human P450 in bacterial mutagenicity tester strain will provide a useful tool for studying the mechanism of the mutagenesis and carcinogenesis of new drugs and environmental chemicals.

• Journal of Microbiology and Biotechnology
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• v.9 no.3
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• pp.303-310
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• 1999

A cost-effective mass production method for a strong antimicrobial peptide, buforin II, which was isolated from the stomach of Bufo bufo gargarizans, has been developed. This method is based on the neutralization of the positive charge of buforin II by fusion with a cysteine-rich acidic peptide (CAP) to avoid any lethal effect on the host. The neutralized fusion peptide was multimerized and expressed in Escherichia coli as tandem repeats to increase the production yield. Multimers of the CAP-buforin II fusion peptide were successfully expressed at high levels in E. coli as inclusion bodies. More than 100mg of pure buforin II was obtained per 11 of E. coli culture after cleaving the multimeric polypeptide with CNBr. The buforin II obtained from the recombinant E. coli had antimicrobial activity identical to that of natural buforin II. The proposed expression system can provide a cost-effective mass production method for both antimicrobial peptides and other host-lethal basic proteins.