• Korean Journal of Microbiology
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• v.49 no.3
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• pp.228-236
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• 2013

Campylobacter jejuni is one of important food-borne pathogens causing human gastroenteritis. We isolated 42 strains of C. jejuni from diarrhea patients and 4 food-poisoning outbreaks in 2010, Gyeonggi-do. In this study, 42 strains were tested for genetic characteristics, the serotype distribution and antimicrobial resistant rate. The presence of hipO (100%), cdtB (100%), and mutated gyrA (95.2%) genes was detected in C. jejuni by polymerase chain reaction (PCR). Detection of mutated gyrA gene correlated with ciprofloxacin resistance. Forty isolates had mutated gyrA gene and were actually resistant to ciprofloxacin. Furthermore, comparing the gyrA DNA sequence data, ciprofloxacin-resistant isolates had a mutation of the DNA sequence from ACA (threonine) to ATA (isoleucine). But 41 strains (97.6%) of patient isolates were susceptible to erythromycin and azithromycin. A total of 35.7% among 42 C. jejuni isolates were identified into 4 different serotypes. The serotype distribution of C. jejuni strains were shown to be HS2(B), HS3(C), HS4(D), HS19(O). To investigate the genotypes of C. jejuni isolated in Gyeonggi province, repetitive sequence polymerase chain reaction (rep-PCR) analysis and SmaI-digested pulsed-filed gel electrophoresis (PFGE) profile analysis were performed. From the PFGE analysis of 42 C. jejuni strains, 12 clusters of PFGE profile were obtained. On the other hand, 11 clusters of rep-PCR profile were obtained from 42 strains of C. jejuni.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.4
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• pp.550-555
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• 1997

Vibrio cholerae non-O1 (V. cholerae non-O1) was previously called nonagglutinable or noncholera vibrios, since it fails to react with polyvalent O1 antisera. This organism is biochemically and genetically indistinguishable from V. cholerae O1 except serological difference. V. cholerae non-O1 strains are often detected in the environment including bays, estuaries, and fresh water, and also found in food. Therefore it is designated food borne bacterium in Japan. However, research papers on V. cholerae non-O1 are very rare in Korea. In order to investigate bacteriological characteristics of V. cholerae non-O1, we isolated V. cholerae non-O1 from the environmental sea water. Among the isolated V. cholerae non-O1 strains, we selected the strain which had the most strong hemolytic activity, named as V. cholerae non-O1 FM-3. The optimum growth conditions of V. cholerae non-O1 FM-3 were $37^{\circ}C$ and pH 8.5 in BHI broth (containing $0.5\%$ sodium chloride), and it grew better than V. cholerae non-O1 ATCC 25872. But both were not able to grow in BHI broth added $5.0\%$ of sodium chloride or adjusted to pH 5.0. According to the experimental results on the susceptibility test against various antibiotics, there were no significant differences between the isolated strain and reference strain (V. cholerae non-O1 ATCC 25872). Most of the antibiotics examined had bacteriostatic action against V. cholerae non-O1 FM-3 while vancomycin, oxacillin, colistin, polymyxin B, and sulfadiazine had no bacteriostatic activity.

• Clinical and Experimental Pediatrics
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• v.48 no.1
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• pp.48-54
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• 2005

Purpose : The pathologic mechanisms of central nervous system(CNS) injuries in human meningitis are not yet completely understood. Recent studies indicate that the host inflammatory responses are as important in brain damage as the infecting organisms and toxins. There have been some reports on the relationship of nitric oxide(NO), macrophage inflammatory protein-$1{\alpha}$(MIP-$1{\alpha}$), and lactoferrin in bacterial meningitis, but few reports in aseptic meningitis. Thus, we investigated the concentrations of NO, MIP-$1{\alpha}$ and lactoferrin in cerebrospinal fluid(CSF) and serum of patients with aseptic meningitis and control subjects and evaluated their relationship with other parameters of meningitis. Methods : CSF and blood were obtained from 25 subjects with aseptic meningitis and 15 control subjects. After centrifugation, supernatants were stored at $-70^{\circ}C$ and we assayed the concentrations of NO, MIP-$1{\alpha}$ and lactoferrin with the ELISA method. There were no patients with neurologic sequelae after being recovered from aseptic meningitis. Results : Concentrations of CSF and serum NO, MIP-$1{\alpha}$ were not increased in aseptic meningitis subjects compared to control subjects. Concentration of CSF lactoferrin was significantly elevated in patients with aseptic meningitis and concentration of serum lactoferrin was significantly decreased in patients with aseptic meningitis compared with those in control subjects(P<0.05). CSF lactoferrin level was positively correlated with CSF WBC counts($r_s=0.449$, P=0.007), especially with neutrophil counts($r_s=0.574$, P<0.001) and CSF protein level($r_s=0.508$, P=0.002). Conclusion : Lactoferrin plays an important role in aseptic meningitis and may be released from neutrophils recruited from blood to the CSF through breakdown of blood-brain barrier. NO and MIP-$1{\alpha}$ may not be important factors in the pathogenesis of aseptic meningitis without neurologic sequelae.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.13 no.2
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• pp.146-153
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• 2010

Purpose: Recent studies have reported an increase in the incidence of community-acquired Clostridium difficile-associated disease (CA-CDAD) among children. There is an overall lack of information on CA-CDAD in the pediatric population. The aim of our study was to compare the epidemiologic and clinical features between CA-CDAD and hospital-acquired C. difficile-associated disease (HA-CDAD) in children. Methods: We retrospectively reviewed the medical records of all patients who were diagnosed with C. difficile-associated disease (CDAD) at Gil Hospital between April 2008 and March 2009. The diagnosis of CDAD was made when patients with gastrointestinal symptoms had positive results for C. difficile toxins A and B assay or stool culture. Results: Sixty-one (male, 32 and female, 29) patients were included. The mean age was 3.79${\pm}$4.54 years. Of the 61 patients, 22 (36.1%) were <1 year of age. Twenty-three patients (37.7%) had a history of antibiotic exposure in the previous 3 months. Forty-one patients (67.2%) were diagnosed with CA-CDAD. There were no significant differences in age, gender, symptoms, laboratory findings, recovery period, complications, and recurrence between the CA-CDAD and HA-CDAD groups. On the other hand, exposure to antibiotics was significantly more frequent among patients in the HA-CDAD group (p=0.005). Conclusion: This study suggests that the occurrence of CA-CDAD is increasing in the pediatric population, especially in younger children with no history of exposure to antibiotics and in outpatients. Awareness of the increasing incidence of CA-CDAD and prompt investigation of C. difficile in susceptible patients is needed to avoid misdiagnosis and for appropriate therapy.

• Journal of Applied Biological Chemistry
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• v.61 no.1
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• pp.83-91
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• 2018

Advances in bacterial and fungal genome mining uncover a plethora of cryptic secondary metabolite biosynthetic gene clusters. Guided by the genome information, targeted transcriptional derepression could be employed to determine the product of a cryptic gene cluster and to explore its biological role. Monascus spp. are food grade filamentous fungi popular in eastern Asia and several genome data belong to them are now available. We achieved transcription activation of a cryptic fungal polyketide synthase-nonribosomal peptide synthase gene Mpfus1 in Monascus purpureus ${\Delta}MpPKS5$ by inserting Aspergillus gpdA promoter at the upstream of Mpfus1 through double crossover gene replacement. The gene cluster with Mpfus1 show a high similarity to those for the biosynthesis of conjugated polyene derivatives with 2-pyrrolidone ring and the mycotoxin fusarin is the representative member of this group. The ${\Delta}MpPKS5$ is incapable of producing azaphilone pigment, providing an excellent background to identify chromogenic and UV-absorbing compounds. Activation of Mpfus1 resulted in a yellow hue on mycelia and its methanol extract exhibit a maximum absorption at 365 nm. HPLC analysis of the organic extracts indicated the presence of a variety of yellow compounds in the extract. This implies that the product of MpFus1 is metabolically or chemically unstable. LC-MS analysis guided us to predict the MpFus1 product and to propose that the Mpfus1-containing gene cluster encode the biosynthesis of a desmethyl analogue of fusarin. This study showcases the genome mining in Monascus and the possibility to unveil new biological activities embedded in it.

• Clinical and Experimental Pediatrics
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• v.48 no.8
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• pp.871-876
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• 2005

Purpose : Recently, it was reported that tumor necrosis factor(TNF) and $lymphotoxin-{\alpha}$($LT-{\alpha}$) gene regions might be a susceptible loci to type 1 diabetes in Japanese. The purpose of this study was to investigate the association of TNF and $LT-{\alpha}$ gene polymorphisms with disease susceptibility in Korean children with type 1 diabetes. Methods : Forty-nine Korean children with type 1 diabetes(29 girls and 20 boys) and 94 healthy Koreans were investigated in this study. Genotyping for -857T/C polymorphism in the TNF promoter region and $LT-{\alpha}$ gene polymorphism were performed by PCR-RFLP(restriction fragment length polymorphism). TNF promoter -1031C/T polymorphism was detected by allele-specific PCR. Results : The distribution of the -857T/C and -1031C/T genotype in the TNF promoter region was not different between diabetic children and the controls. The frequency of TT genotype in the distribution of TNF -1031C/T polymorphism in diabetic children with diabetic ketoacidosis(DKA) at diagnosis was significantly lower than those without DKA(P<0.05). No significant difference in the distribution of $LT-{\alpha}$ gene polymorphism was observed between diabetic children and the controls. There was no association between clinical characteristics of type 1 diabetes and $LT-{\alpha}$ gene polymorphisms. Conclusion : These results suggest that TNF promoter -857T/C and $LT-{\alpha}$ gene polymorphisms are not associated with susceptibility to type 1 diabetes in Korean children. TNF promoter -1031C/T polymorphism might be related to clinical manifestations(DKA) of type 1 diabetes.

• Analytical Science and Technology
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• v.24 no.2
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• pp.150-157
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• 2011

Aflatoxins are secondary metabolites of the molds of Aspergillus flavus and Aspergillus parasiticus. They are highly carcinogenic compounds and can affect a wide range of vegetable commodities such as cereals (especially corn), nuts, peanuts, fruits and oil seeds, in the field and during storage. In fact, oilseeds are often stored for weeks in conditions that promote the mould growth, and the possible consequent presence of aflatoxins in oilseeds can lead to their transfer in oil. In addition, aflatoxins can be found as a natural contaminant in multi-cereals and beans making baby food for infants and young-children. The objective of this study was to validate the liquid extraction method or develop an analytical method for edible oil and infant-children foods. Therefore, this study developed condition of extract for aflatoxins ($B_1$, $B_2$, $G_1$ and $G_2$) in edible oil using a high performance liquid chromatography with florescence detector (HPLC/FLD). Aflatoxins were extracted from edible oil samples by means of MSPD (Matrix solid phased dispersion), utilizing $C_{18}$ as dispersing material and purified by using immunoaffinity column. The gression line coefficients were above 0.999. The recoveries for aflatoxins ranged from 85.9 to 93.0%, and relative standard deviations were below 5.7%. The new developed method of aflatoxins effectively enhanced recoveries by using MSPD-Immunoaffinity column compared with liquid extraction. The analytical method for liquid extraction of aflatoxin was appropriate for infant-children food. Reviewing the current method, the recoveries of aflatoxins ($B_1$, $B_2$, $G_1$ and $G_2$) were 89.5~92.3%.

• Tuberculosis and Respiratory Diseases
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• v.43 no.1
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• pp.46-53
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• 1996

Background: Endotoxin or lipopolysaccharide(LPS) can prime phagocytic cells such as polymorphonuclear leukocytes, monocytes or animal peritoneal macrophages to generate increased amounts of secretory products such as oxygen free radicals and tumor necrosis factor, which play an important role in developing adult respiratory distress syndrome in gram negative sepsis. Human alveolar macrophages(HAM) are continuously exposed to various stimuli inhaled into the alveoli, and the response to LPS might be different in HAM. Therefore, we investigated the effect of LPS pre-exposure on HAM adhered to plastic surface and A549 cell(type II human alveolar epithelial cell line) monolayer. Methods: HAM were isolated from bronchoalveolar lavage fluid from normal lung of the patients with localized lung cancer and esophageal cancer. LPS was exposed to HAM for 2hrs before or after adherence to plastic surface of 24-well Linbro plate and A549 cell monolayer. And then HAM was stimulated with PMA(phorbol myristate acetate) or fMLP(N-formyl-methionylleucyl-phenylalanine). The amount of hydrogen peroxide($H_2O_2$) production in the supernatant was measured on the principle of peroxidase-dependent oxidation of phenol red by hydrogen peroxide. Results: LPS pre-exposure could not enhance $H_2O_2$ production in neither HAM adhered to plastic surface nor one to A549 cell monolayer. But LPS even in the absence of PMA or fMLP stimulation directly increased $H_2O_2$ release in HAM if added after the adherence to A549 cell monolayer. Conclusion: Endotoxin does not prime HAM, but may directly activate HAM adhered to alveolar epithelial cells. Further investagation will be necessary.

• Korean journal of applied entomology
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• v.47 no.1
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• pp.87-93
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• 2008

Bacillus thuringiensis with selected high toxicities against tobacco cutworm, Spodoptera litura were isolated from domestic soils. When being observed under a phase-contrast microscope, the insecticidal crystal proteins were showed a bipyramidal crystal types. New CAB 109 isolate was identified to B. thuringiensis subsp. aizawai in the H serotype. As a results of insecticidal activities between CAB 109 isolate and 3 existing ready-made products against 3rd larva of S. litura, CAB 109 isolate showed 100% mortality with spore concentration $(1.3{\times}10^7cfu/ml)$. It was a very high insecticidal activity compared with a existing ready-made B. t. products. $LD_{50}$ values of CAB 109 isolate was $9.78{\times}10^5,\;6.87{\times}10^6\;and\;1.83{\times}10^7cfu/ml$ spore concentration against 2nd, 3rd and 4th larva of S. litura, respectively. Unlike Plutella xylostella, S. litura was slowly died after application up to 7 days. The weight of S. litura larva applied with CAB 109 isolate were 6-7 times less than controlled group. Even though it didn't die, it did not grow into next larva. The result observed with scanning electron microscope was that CAB 109 isolate of B. t. aizawai formed a typical bipyramidal crystal protein type. Otherwise, when CAB 109 isolate was examined with SDS-PAGE and with trypsin, there was no difference between CAB 109 strain and ready-made products of B. thuringiensis.

• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.741-755
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• 1995

Currently titanium is the material of choice for implants because of its biological acceptance. This high degree of biocompatibility is thought to result, in part, from the protective and stable oxide layer that presumably aids in the bonding of the extracellular matrix at the implant-tissue interface. Endosseous dental implants are interfaced with bone, connective tissue, and epithelium when implanted into the jaw bone. The soft tissue interface including connective tissue and epithelium is one of the most critical factors in the determination of implant maintenance and prognosis. For maintenance of failing or failed implants, it is essential to treat the implant fixture surface to remove bacterial endotoxins and make a surface tolerated by surrounding soft and hard tissues. In this study, the effect of mechanical treatment on titanium plasma sprayed implant on adhesiveness and proliferation of human gingival fibroblasts and changed surface characteristics were studied. titanium plasma sprayed discs manufactured by Friedrichsfeld company were treated with loaw speed stone bur, a rubber point and a jetpolisher. Its surface components were analyzed with Energy dispersive X-ray spectroscopy to evaluate whether the surface characteristics were altered or not. To observe the spreading pattern of the human gingival fibroblasts which attached to the all specimens author used the scanning electron microscope. The results were as follows : Pure titanium and plasma sprayed titanium, stone polished titanium showed titanium peak and small amout of aluminum, so there was no alteration on surface characteristics. Under the scanning electron microscopic examination in the initial attachment of human gingival fibroblast, there was a slight enhancement in pure titanium, stone polished titanium than plasma sprayed titanium. After 6 hours, the pure titanium and stone polished titanium showed human gingival fibroblasts were elongated and connected with numerous processes. Human gingival fibroblasts were more intimately attached on the pure titanium discs than on the other discs. The human gingival fibroblasts attached on the plasma sprayed titanium by thin and elongated processes. After 24 hours, the human gingival fibroblasts connected with each other via numerous processes and compeletly covered the pure titanium and stone polshed titanium discs. Human gingival fibroblasts had multiple point contacts with more long and thin lamellopodia and showed a little bare surface on plasma sprayed titanium discs.