• Korean Journal of Veterinary Research
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• v.45 no.1
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• pp.45-53
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• 2005

GroE that is a heat shock protein composed of GroEL and GroES is known as an immunodominant target of both the humoral and cellular immune responses in bovine brucellosis. This study was carried out to characterize groE gene encoding heat shock proteins of B. abortus isolated in Korea and to evaluate the immunogenicity of the GroE protein expressed in E. coli system. In PCR the specific signals with the size of 2,077 bp were detected in five strains isolated from the mammary lymphnodes of the dairy cattle that were serologically positive and the reference strains. In comparison of the sequences of nucleotides and amino acids among the strains, GroES showed 100% identity in both sequences. GroEL was evaluated 99.0~99.9% in nucleotides and 98.0~100% homology in amino acids. The groE gene including groES and groEL was inserted into pET29a vector and constructed pET29a-GroE recombinant plasmids. The inserted groE was confirmed by digestion with Nco1 and EcoR1 endonucleases and nucleotide sequencing. E. coli BL (DE3) was transformed with pET29a-GroE, named as E. coli BL (DE3)/pET29a-GroE. In SDS-PAGE, it was evident that the recombinant plasmid effectively expressed the polypeptides for GroES (10 kDa) and GroEL (60 kDa) in 0.5, 1 and 2 hours after IPTG induction. The immuno-reactivity of the expressed proteins were proved in mouse inoculation and Western blot analysis.

• Korean Journal of Veterinary Research
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• v.30 no.2
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• pp.255-260
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• 1990

This study was conducted to examine the enteropathogens and clinical aspects of diarrhea of the 211 Korean native calves during the suckling period. The experimental results were summerized as follows: 1. The 206 Korean native calves (97.6%) were affected with diarrhea during the suckling period. 2. Of 156 diarrheal feces tested, Rotavirus were detected from 108(69.2%) feces of $K^+99$ E coli were detected from 23(14.7%) feces and Eimeria spp were detected from 33(21.2%) feces. But Salmonella spp and Cryptosporidium spp were not detected. 3. Rotavirus were detected from 2 to 84 days of life, $K^+99$ E coli were detected from 5 to 54 days and Eimeria spp were detected from 33 to 84 days of life. 4. Physical appearances of the diarrheal feces were not affected specifically according to the enteropathogens, but were affected by the severity of diarrhea and the diets.

• The Korean Journal of Nuclear Medicine
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• v.35 no.1
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• pp.75-80
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• 2001

Purpose: There was little evidence that Tc-99m labeled ciprofloxacin (Infecton) located inside of bacteria. Antimicrobial activity of Infecton could be an indirect evidence of its location. We compared in vitro antimicrobial activities of Infecton and ciprofloxacin. Materials and methods: Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Infecton and ciprofloxacin against three standard strains of bacteria, Staphylococcus aureus ATCC 29213, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853 were measured using modified broth macrodilution techniques and pour plate methods, respectively. Data were expressed as mean${\pm}$SE (range). Results: MICs of Infecton and ciprofloxacin were $1.12{\pm}0.20\;(0.8{\sim}1.6){\mu}g/ml\;and\;0.35{\pm}0.04\;(0.2{\sim}0.4){\mu}g/ml$ for S. aureus, $0.03{\pm}0.005\;(0.025{\sim}0.05){\mu}g/ml\;and\;0.011{\pm}0.001\;(0.006{\sim}0.012){\mu}g/ml$ for E. coil, and $0.96{\pm}0.16\;(0.8{\sim}1.6){\mu}g/ml)\;and\;0.56{\pm}0.098\;(0.4{\sim}0.8){\mu}g/ml$ for P. aeruginosa, respectively. MBCs of Infecton and ciprofloxacin were $2.56{\pm}0.39\;(1.6{\sim}3.2){\mu}g/ml\;and\;0.88{\pm}0.2\;(0.4{\sim}1.6){\mu}g/ml$ for S. aureus, $0.04{\pm}0.05\;(0.025{\pm}0.05){\mu}g/ml\;and\;0.02{\pm}0.01\;(0.025{\sim}0.05)\;{\sim}g/ml$ for E coli, and $2.24{\pm}0.39\;(1.6{\sim}3.2){\mu}g/ml\;and\;1.44{\pm}0.16\;(0.8{\sim}1.6){\mu}g/ml$ for P. aeruginosa, respectively. Conclusion: Although both MICs and UBCs of Infecton were higher than those of ciprofloxacin, all three standard bacterial strains were sensitive to Infecton. It could be an indirect evidence that Tc-99m Infecton be a specific imaging agent for bacterial infection.

• Journal of the Korean Ceramic Society
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• v.50 no.4
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• pp.245-250
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• 2013

A hydroxyapatite air filter was made with hydroxyapatite powder, water and chitosan solution. The structures of the sintered HAp samples were determined by MP-XRD. Hydroxyapatite has antibacteria properties against Staphylococcus aureus, Klebsiella pneumoniae and Escherichia coli. The bacteria removal rate was 99.9%. In the case of Pseudomonas aeruginosa, Colon bacterium and Listeria monocytogenes, the hydroxyapatite air filters had a clear zone which confirmed antibacteria properties. Using the microscopy, we observed that the HAp powder absorbed E. coli bacteria.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.4
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• pp.361-369
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• 1997

A microbiological nitrate determination method by E. coli is modified in Korea, using K12 wildtype, KCTC 1116, for the quantitative reduction of $NO_3{^-}$ to $NO_2{^-}$. The nitrate in plant, soil or water sample is determined spectrophotometrically after being diazotized with sulfaniamide and N-(1-naphthl)-ethlenediamine. The modified E. coli cell method and principle for nitrate determination using Korean wildtype E. coli strain is described, and cell culture and preparation of stock suspension for E. coli as well. This modified E. coli cell method can be managed simply and fast, it is suitable for the investigation of the large serials, it can be also automated and has a high degree of sensitivity up to 0.01ppm $NO_3{^-}-N$ in the sample solution. The applicability of the modified E. coli cell method has been tested for plant, soil and water analysis on a wide range of different samples. Recovery rates of added nitrate have been determined and comparisons with other standard nitrate analytical procedures have been carried out. The results with the modified E. coli cell method show high correlation ($r^2=0.98$) with those gained by the standard analytical procedures. The advantages and disadvantages of the method are also discussed to other nitrate determination methods.

• Korean Journal of Microbiology
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• v.40 no.2
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• pp.104-110
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• 2004

To determine evolution and genotype of new chromosomal AmpC $\beta$-lactamases among clinical isolates of Enterobacter species, we performed antibiotic susceptibility testing, pI determination, sequencing, and phy-logenetic analysis using developed expression/secretion vector. Six isolates have shown to produce AmpC $\beta$-lactamases. Six genes of AmpC $\beta$-lactamases that are responsible for the resistance to cephamycins (cefoxitin and cefotetan), amoxicillin, cephalothin, and amoxicillin-clavulanic acid were cloned and characterized in pMSG12119. Insert fragment containing the ampC genes was sequenced and found to have an open reading frame coding for 381-amino-acid $\beta$-lactamase. The nucleotide sequence of four ampC genes ($bla_EcloK992004.l$, $bla_EcloK995120.1$, $bla_EcloK99230$, and $bla_EareK9911729$) shared considerable homology with that of chromosomal ampC gene ($bla_EcloMHN1$) of E. cloacae MHN1 (more than 99.6% identity). The sequences of two ampC genes ($bla_EcloK9973$ and $bla_EcloK9914325$) showed close similarity to the chromosomal ampC gene ($bla_EcloQ908R$) of E. clo-acae 908R (99.7% identity). The results from phylogenetic analysis suggested that six ampC genes could be originated from $bla_EcloMHN1$ / or $bla_EcloQ908R$ / MIC patterns and exact pI values of six transformants indicated that the developed expression/secretion vector (pMSG1219) was suitable for the characterization of foreign genes in E. coli strain.

• Microbiology and Biotechnology Letters
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• v.37 no.3
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• pp.197-203
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• 2009

An indole oxygenase originated from Rhodococcus sp. RHA1 was cloned into the expression vector, pTrc99A, in Escherichia coli, and designated pTCAN1. The pTCAN2 was constructed from pTCAN1 by the deletion of $lacI^q$ for the constitutive expression of indole oxygenase without adding IPTG in the medium. The complete open reading frame of indole oxygenase was 1,224 bp long, which encodes a protein of 407amino acids. Crude extracts of E. coli $DH5{\alpha}$/pTCAN1 and pTCAN2, respectively, were prepared and subjected to SDS-PAGE analysis. A band corresponding to molecular mass of about 43 kDa was appeared and this result correlated with the predicted molecular mass of cloned indole oxygenase. The E. coli harboring pTCAN1 and pTCAN2, respectively, showed blue color colony in LB plate. The pigment showing blue color was prepared from E. coli $DH5{\alpha}$/pTCAN2, and identified as indigo by experiments using spectrophotometer, HPLC, and TLC. The indigo-forming activity of indole oxygenases from the whole cell of E. coli $DH5{\alpha}/pTCAN1$ cultured at LB medium added 1mM of IPTG and that of E. coli/pTCAN2 showed about 1.75nmol/min/mg DCW (dry cell weight) and 3.85 nmol/min/mg DCW, respectively. Also, the E. coli $DH5{\alpha}$/pTCAN2 produced about $236{\mu}M$ of indigo after 48 hours incubation in TB medium supplemented with 2.5 mM of tryptophan.

• Journal of Food Hygiene and Safety
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• v.32 no.6
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• pp.507-512
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• 2017

There has been increasing concern regarding misuse of disinfectants and sanitizers such as ethanol, sodium hypochlorite, and hydrogen peroxide for food contact surfaces in the food industry. Examining the efficacy of the concentration of currently used disinfectants and sanitizers is urgently required in the Korean society. This study aimed to develop predictive reduction models for Escherichia coli and Staphylococcus aureus in suspension, as a function of $ClO_2$ (chlorine dioxide) and contact time using response surface methodology. E. coli ATCC 10536 and S. aureus ATCC 6538 (initial inoculum, 8-9 log CFU/mL) in tryptic soy broth were treated with different concentrations of $ClO_2$ (5, 20, and 35 ppm) for different contact times (1, 3, and 5 min) following a central composite design. The polynomial reduction models for $ClO_2$ on E. coli and S. aureus were developed under the clean condition. E. coli reduction by 35 ppm $ClO_2$ for 1, 3, and 5 min was 2.49, 2.70, and 3.65 log CFU/mL, respectively. Also, S. aureus reduction by 35 ppm $ClO_2$ for 1, 3, and 5 min was 4.59, 5.25, and 5.81 log CFU/mL, respectively. The predictive response polynomial models developed were $R=0.43231-0.056492^*X_1-0.097771^*X_2+9.24167E-003^*X_1^*X_2+3.06333E-003^*X_1{^2}$ ($R^2=0.98$) on E. coli and $R=1.10542-0.20896^*X_1-0.046062^*X_2+8.30000E-003^*X_1^*X_2+8.73300E-003^*X_1{^2}$ ($R^2=0.99$) on S. aureus, where R was the bacterial reduction (log CFU/mL), $X_1$ was the concentration and $X_2$ was the contact time. Our predictive reduction models should be validated in developing the optimal concentration and contact time of $ClO_2$ for inhibiting E. coli and S. aureus on food contact surfaces.

• Food Science of Animal Resources
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• v.28 no.1
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• pp.99-104
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• 2008

A lactic acid bacterium showing growth inhibitory activity against Enterobacter sakazakii was isolated from bovine intestinal tracts. From biochemical and molecular biological studies, the isolate was identified and named as Enterococcus faecium JH95. This strain was resistant to kanamycin and streptomycin at a concentration of $100{\mu}g/mL$. E. faecium JH95 had high antimicrobial activity against food-borne pathogens such as Escherichia coli O157:H7, Listeria monocytogenes, Salmonella typhimurium, Staphylococcus aureus, and Clostridium perfrigens. The culture supernatant of this strain did not have antimicrobial activity. The culture broth of this strain failed to show the antimicrobial activity by heat treatment at $100^{\circ}C$ for 5 min or by pretense treatments for 2 hr. This result suggested that the putative antimicrobial substance produced by E. faecium JH95 is likely a protein which is not secreted into culture medium.

• Korean Journal of Poultry Science
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• v.32 no.4
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• pp.261-268
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• 2005

The purpose of this study was to evaluate the effect of dietary ceramic powder on laying performance, Pathogenic bacterial (E. coli, salmonella) counts in caecal contents and excreta, malodorous substances $(NH_3,\;H_2S,\;VFA)$ in excreta and fatty acid composition of e99 yolk in laying hens. Three hundred sixty layers at 34 weeks of age were divided into three groups of 120 hens each and each group was fed diets containing 0 (control), 0.4, or 0.8 ceramic powder for six weeks. It is concluded that $0.4\%$ ceramic powder supplementation of diets decreased of E. coli, salmonella counts in the intestine and emission of $NH_3$ and VFA gas from excreta, and improved the laying Performance and ratio of egg yolk fatty acids contents.