• BMB Reports
• /
• v.29 no.2
• /
• pp.116-121
• /
• 1996

In earlier studies, the genes encoding Escherichia coli thioredoxin and Corynebacterium nephridii thioredoxin C-3 were fused via a common restriction site in the nucleotide sequence coding for the active site of the proteins to generate two chimeric thioredoxins, designated E-C3 (N to C-terminal) and C3-E. The hybrid thioredoxins were overexpressed in E. coli from the cloned chimeric thioredoxin genes by a T7 promoter/polymerase system. To investigate the structure-function relationship of thioredoxin, we purified the E-C3 hybrid thioredoxin through ammonium sulfate fractionation, DEAE-cellulose chromatography, and Sephadex G-50 gel filtration. Its purity was examined on SDS-polyacrylamide gel electrophoresis and the molecular weight of the purified E-C3 hybrid thioredoxin was estimated to be 12,000. On native polyacrylamide gels, the purified E-C3 hybrid thioredoxin shows a much lower mobility than E. coli thioredoxin. E-C3 hybrid thioredoxin exhibits a 40-fold lower catalytic efficiency with E. coli thioredoxin reductase than E. coli thioredoxin. It was shown to catalyze the reduction of insulin disulfide by dithiothreitol. The purified E-C3 hybrid thioredoxin was also characterized in other aspects.

• Asian-Australasian Journal of Animal Sciences
• /
• v.19 no.11
• /
• pp.1665-1670
• /
• 2006

The objective of this research was to provide the characterization and method for producing anti-E. coli O157:H7 antibodies in egg-laying hens and to determine if the antibody can restrain the proliferation of E. coli O157:H7 in-vitro. Selected antigenic fractions (whole cell, outer membrane protein and lipopolysaccharide (LPS)) from E. coli O157:H7 were injected to hens in order to produce anti-E. coli O157:H7 antibodies. The immune response and the egg yolk antibodies of laying hens against the whole cell, outer membrane protein and LPS antigens were monitored by ELISA. The level of antibodies against whole cell antigen monitored through ELISA sharply increased after the initial immunization, and it was found to be maximum on day 49 however, the level was maintained up to day 70. Antibodies (5 mg/ml) directed against the whole cell inhibited E. coli proliferation 10-13 times more than outer membrane protein or LPS. The antibody response against the whole cell antigens appeared to have higher activity in restraining the proliferation of E. coli O157:H7 than antibody against outer membrane protein or LPS. Results reflected that increasing the IgY's in the egg yolk could prevent greater economic losses due to human and animal health from pathogenic bacteria i.e. E. coli O157:H7.

• Pediatric Infection and Vaccine
• /
• v.16 no.2
• /
• pp.162-166
• /
• 2009

Purpose : Urinary tract infection (UTI) is one of the most common bacterial infectious disease in childhood. Renal scarring is an important complication of UTIs. Known risk factors for renal scarring are younger age, anatomic defects, delayed treatment, and causative pathogens other than Escherichia coli. The aim of this study was to compare the characteristics of clinical and laboratory features of UTI with E. coli to those with non-E. coli in infants. Methods : We reviewed the medical records of 1,120 infants under 12 months of age who had been admitted for UTIs between January 1998 and December 2007. All patients who were diagnosed with UTIs were divided into two groups (E. coli and non-E. coli UTIs). Results : Three hundred twenty-four of 1,120 cases met the inclusion criteria. The number of E. coli and non-E. coli UTIs was 273 (84.3%) and 51 (15.7%), respectively. As compared to the non-E. coli UTI group, the E. coli UTI group was younger (3.59 vs. 4.47 months, P =0.008), a longer duration of pyuria (3.96 vs. 3.06 days, P =0.01), higher peripheral white blood cell counts (13.89 vs. $12.13{\times}10^3/mm^3$, P =0.043), and lower rates of high degree (III-V) vesico-ureteral reflux (P =0.005). Conclusion : UTIs with E. coli might have more severe clinical features and a lower prevalence of high grade vesicoureteral reflux than UTIs with non-E. coli. However, no difference was noted in the clinical response to antibiotic therapy between the two groups.

• Korean Journal of Microbiology
• /
• v.22 no.3
• /
• pp.167-173
• /
• 1984

The cellabiase (${\beta}$-glucosidase) gene in a Cellulomonas sp. CS1-1 was cloned into E. coli HB101 using the vector plasmid pBR322, and the expression of the gene in E. coli studied. The chromosomal DNA of the cellulomonas was digested by seveal restriction enzymes, each of which has only one cleaving site in plasmid pBR322. The recombinant plasmid, pSB2, created with Sal I frament, was expressed for the cellobiase gene in E. coli. The recombiant plasmid was estimated to contain 6.4 Kb foreign DNA at the Sal I site of plasmid pBR322 and the inserted DNA was mapped by single and double digestion with several enzymes. E. coli HB101(pSB2) has slowly grown in a mineral liquid medium containing cellobiose as a sole carbon source. The cellobiase activity in the transformed E. coli was 132 units per liter, which is equivalent to one twenty fifth of that in doner strain Cellulomonas sp. CS1-1. The transforned cell with plasmid containing cellulase gene grow well in the LB mediuns. The synthesis of cellobiase in the strain, E. coli HB101 (pSB2), was inhibited by glucose and at high concentration of cellobiose, and induced by cellobiose at low concentration.

• Membrane and Water Treatment
• /
• v.10 no.3
• /
• pp.231-237
• /
• 2019

Peroxymonosulfate (PMS) in combination with Cu(II) was examined to inactivate E. coli and MS2 coliphage in natural water. The combined system (i.e., the Cu(II)/PMS system) caused a synergistic inactivation of E. coli and MS2, in contrast with either Cu(II) or PMS alone. Increasing the concentration of PMS enhanced the inactivation of E. coli and MS2, but after a certain point, it decreased the efficacy of the microbial inactivation. In the Cu(II)/PMS system, adding reactive oxidant scavengers marginally affected the E. coli inactivation, but the inhibitory effects of copper-chelating agents were significant. Fluorescent assays indicated that the Cu(II)/PMS system greatly increased the level of reactive oxidants inside the E. coli cells. The sequential addition of Cu(II) and PMS inactivated more E. coli than did adding the two simultaneously; in particular, the inactivation efficacy was much higher when Cu(II) was added first. The observations from the study collectively showed that the microbial inactivation by the Cu(II)/PMS system could be attributed to the toxicity of Cu(I) as well as the intracellular oxidative stress induced by Cu(III) or radical species.

• Korean Journal of Veterinary Research
• /
• v.55 no.3
• /
• pp.191-197
• /
• 2015

Escherichia (E.) coli is commensal bacteria found in the intestine; however, some pathogenic strains cause diseases in animals and humans. Although E. coli does not typically produce hydrogen sulfide ($H_2S$), $H_2S$-producing strains of E. coli have been identified worldwide. The relationship between virulence and $H_2S$ production has not yet been determined. Therefore, characteristics of $H_2S$-producing isolates obtained from swine feces were evaluated including antibiotic resistance patterns, virulence gene expression, and genetic relatedness. Rates of antibiotic resistance of the $H_2S$-producing E. coli varied according to antibiotic. Only the EAST1 gene was detected as a virulence gene in five $H_2S$-producing E. coli strains. Genes conferring $H_2S$ production were not transmissible although the sseA gene encoding 3-mercaptopyruvate sulfurtransferase was detected in all $H_2S$-producing E. coli strains. Sequences of the sseA gene motif CGSVTA around Cys238 were also identical in all $H_2S$- producing E. coli strains. Diverse genetic relatedness among the isolates was observed by pulsed-field gel electrophoresis analysis. These results suggested that $H_2S$-producing E. coli strains were not derived from a specific clone and $H_2S$ production in E. coli is not associated with virulence genes.

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

• Pediatric Infection and Vaccine
• /
• v.4 no.1
• /
• pp.73-78
• /
• 1997

Purpose : Escherichia coli O157 can produce diarrhea as well as hemorrhagic colitis and hemolytic uremic syndrome. In many parts of North America, E. coli O157 often is the second or third most commonly isolated enteric bacterial pathogens. Recently, intakes of fast food, including hamburgers have increased in Korea. Therefore, E. coli O157 infection in Korea are likely to be increased. Methods : Stool samples from 317 pediatric diarrheal patients were analyzed by culture on sorbitol-MacConkey agar. Sorbitol-negative colonies were teated by E. coli O157 latex agglutination test. Results : Of the 317 specimens, one (0.3%) were E. coli O157:NM that not produced Shiga toxin. The 7 year old male patient who had complained of abdominal pain, vomiting and non-bloody diarrhea for 2 days. The patient was improved for 2 days after admission. Conclusions 1 Only one (0.3%) of all fecal samples were isolated E. coli O157 that not produced Shiga toxin. Therefore, routine stool culture for the isolation of E. coli O157 was not likely to be neccessary so far.

• Journal of Life Science
• /
• v.14 no.5
• /
• pp.868-873
• /
• 2004

The efficient fermentative production of L-threonine fermentation was achieved by using Escherichia coli MT201, transformed a plasmid carrying pyruvate carboxylase gene. It is an attempt to supply oxaloacetate to the L-threonine biosynthetic pathway. In order to improve the L-threonine productivity of E. coli MT201, a plasmid pPYC which is an expression vector of the pyruvate carboxylase gene of Coryne-bacterium glutamicum, was introduced. When E. coli MT/pPYC was incubated with medium containing only glucose as a carbon source, both the cell growth and L-threonine production were reduced, compared to the results from fermentation of E. coli MT201. In order to circumvent this effect, we attempted the addition of a mixed carbon source, composed of glucose and sodium citrate at a ratio of 1.5:3.5. It was shown that L-threonine production and cell growth (OD660) with E. coli MT/pPYC reached up to 75.7 g/l and 48, respectively, at incubation for 75 hr under fed-batch fermentation conditions. It is assumed that overproduction of L-threonine by anaplerotic pathway leads unbalance of TCA cycle and sodium citrate might playa role to recover normal TCA cycle.

• Korean Journal of Veterinary Research
• /
• v.43 no.3
• /
• pp.415-421
• /
• 2003

It is now generally accepted that acupuncture is effective in diarrhea caused by bacterial infection. However, its effect on the intestinal smooth muscle dysfunction is not clear. Therefore, we investigated the effect of acupuncture therapy at Jiao-chao (GV-1) on the intestinal muscle dysfunction in weaning piglets orally infected by Escherichia coli. The animals are divided into four groups; 1) E. coli + no-treatment, 2) E. coli + antibiotic, 3) E. coli + acupuncture, 4) normal group. In the three E. coli infected groups, low frequency electrical field stimulation (EFS, 1 Hz) provoked triphasic responses composed of initial relaxation followed by on-contraction and off-contraction. While in the normal group, EFS (1Hz) induced biphasic responses composed of relaxation during the stimulation and off-contraction. At the high frequency (16Hz) EFS, both on-contraction and off-contraction of the E. coli + antibiotic, E. coli + acupuncture and the normal group were larger than those of the E. coli + no-treatment group. In the non-adrenergic non-cholinergic (NANC) condition, only biphasic responses occurred to EFS in all experimental groups and the off-contraction of E. coli + antibiotic, E. coli + acupuncture and the normal group were larger than those of the E. coli + no-treatment group. The response to carbachol of those three groups was also significantly greater than that of the E. coli + no-treatment group. These results suggest that acupuncture is as effective as antibiotic in the dysfunction of colonic circular muscle caused by E. coli infection. The maintenance of contractile neuromuscular transmission seems to be involved in the mechanism of the acupuncture effects on diarrhea.