• Biomedical Science Letters
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• v.6 no.3
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• pp.201-208
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• 2000

The vancomycin, one of the family of glycopeptide antibiotics, inhibits the synthesis of bacterial cell wall peptidoglycan and has been widely used against gram-positive bacterial infections, especially for a treatment of methicillin resistant S. aureus infection. However, clinical isolate which was intermediately resistant to vancomycin (Mu50: MIC 8 $\mu\textrm{g}$/ml) was isolated in recent years. In this study we performed vancomycin susceptibility test with the increment method and population analysis with clinical isolates S. aureus. Also we did several kinds of tests with three selected isolates (s129: MIC 7 $\mu\textrm{g}$/ml, s134: MIC 7 $\mu\textrm{g}$/ml, s135: MIC 8 $\mu\textrm{g}$/ml) to find out possible mechanism of vancomycin resistance. As a result, the prevalence of vancomycin resistant S. aureus isolates among S. aureus strains resistant to methicillin was 23.3% (25/107). The vancomycin resistances of isolated strains of S. aureus were between those of Mu5O and Mu3 strains. By PCR analysis, none of the isolates with decreased vancomycin susceptibility contained known vancomycin resistant genes such as vanA, vanB, vanC1, vanC2, and vanH. Major bands of 81 kDa, 58 kDa, 33 kDa, 28 kDa were demonstrable in whole cell lysates by SDS-PAGE from all three isolates as well as reference strains. And especially,45 kDa protein was overproduced in Mu50 strains. Among them increased production of NAD$^{+}$-linked-$_{D}$-lactate dehydrogenase (dnLDH) were detected from one clinical strain (s135) and Mu5O strain. From these data, we suggest that the mechanism of vancomycin resistance in these isolates are distinct from that in enterococci.

• Biomolecules & Therapeutics
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• v.28 no.3
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• pp.272-281
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• 2020

Environmental agents, including viral and bacterial infectious agents, are involved in the alteration of physicochemical and biological parameters in the nasal epithelium. Hyaluronan (HA) has an important role in the regulation of tissue healing properties. High molecular weight HA (HMW-HA) shows greater anti-inflammatory responses than medium molecular weight HA (MMW-HA) and low molecular weight HA (LMW-HA). We investigated the effect of HMW-HA, MMW-HA and LMW-HA on the regulation of physicochemical and biological parameters in an "in vitro" model that might mimic viral infections of the nasal epithelium. Human nasal epithelial cell line RPMI2650 was stimulated with double-stranded RNA (dsRNA) Poly(I:C) for 5 days in air-liquid-interface (ALI) culture (3D model of airway tissue). dsRNA Poly(I:C) treatment significantly decreased transepithelial electrical resistance (TEER) in the stratified nasal epithelium of RPMI2650 and increased pH values, rheological parameters (elastic G' and viscous G''), and Muc5AC and Muc5B production in the apical wash of ALI culture of RPMI2650 in comparison to untreated cells. RPMI2650 treated with dsRNA Poly(I:C) in the presence of HMW-HA showed lower pH values, Muc5AC and Muc5B production, and rheological parameters, as well as increased TEER values in ALI culture, compared to cells treated with Poly(I:C) alone or pretreated with LMW-HA and MMW-HA. Our 3D "in vitro" model of epithelium suggests that HMW-HA might be a coadjuvant in the pharmacological treatment of viral infections, allowing for the control of some physicochemical and biological properties affecting the epithelial barrier of the nose during infection.

• Korean Journal of Food Science and Technology
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• v.10 no.2
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• pp.136-142
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• 1978

The young cells of Clostridiunm saccaroperbutylacetonicum were rapidly autolysed by exposing them to the hypertonic solution of sucrose(0.3-0.6M) without any other supplement to decompose the rigid cell wall. The cells were converted into the spherical cells by lysis. The spherical cells had following properties: (1) they were absent in the cell wall and osmotically fragile. (2) they were stabilized in the existence of 0.4M sucrose and 5mM $MgSO_4$ (3) they were resistant against adsorption of phage particles. (4) they allowed infection of the isolated phage DNA and produced progeny phage particles. (5) they were able to biosynthesize their macromolecules for a few hours according to a balanced manner of biosynthesis. (6) they were able to produce the bacteriocin particles by mitomycin C treatment. (7) they were unable to multiply. These results were all in the level of typical properties of bacterial protoplasts. It was apparent that the spherical cells formed by lysis occcurring by treatment with hypertonic sucrose were protoplasts.

• The Korean Journal of Physiology and Pharmacology
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• v.11 no.2
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• pp.65-70
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• 2007

Chinese herb medicines have traditionally been used to treat or alleviate the symptom of various diseases. The rationale for use of certain herbs to certain disorder is now getting unveiled by modern technology. In the present study, we investigated whether herb mix extract(HMX), which is alleged to be useful for gastric ulcer, protects stomach from oxidative stress. Rats were allowed to normal diet with and without HMX (1, 5, 10 mg/kg) for 30 days. To induce gastric ulcer, ethanol (75%, 1.5 ml) or acidified aspirin (100 mg/kg in 0.2 N HCl) was administered by oral route in 24 h-fasted rats and examined the gastric ulceration(bleeding) by measuring the size 1 h after the treatment. Results indicated the area of gastric bleeding was significantly less in HMX fed rats than in normal diet fed ones, and it was dependent on the duration and amount of HMX. To investigate the underlying mechanism by which HMX protects stomach from oxidative stress, expression of enzymes like heme oxygenase (HO), cyclooxygenase (COX), and inducible nitric oxide (iNOS) were investigated in MKN-74 cells, where aspirin or H. pylori was introduced. The results were compared with RAW 264.7 cells to check if there's cell specificities exist. The expression of HO-1 but not COX-2, iNOS was significantly increased by HMX. Furthermore, HO-1 inhibitor, SnPP IX reduced the HO-1 activity and reversed the survival rate in HMX-treated MKN-74 cells. There's no difference between RAW 264.7 cells and MKN-74 cells. We, thus, concluded that HMX is beneficial for protection from oxidative injury, and induction of HO-1 by HMX in gastric cells is, at least, responsible for protection from oxidative stress such as ethanol, aspirin and possibly H. pylori infection.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.4
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• pp.373-385
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• 2004

Statement of problem: The microbial adhesion on the surface of materials used in prosthodontics and restorative dentistry significantly influences microbial infection. Purpose: The purpose of this study was to evaluate the effect of how the degree of surface roughness of acrlyic resin affect the adhesion of bacteria. Material and methods: Resins were finished with $50{\mu}m$ and $250{\mu}m$ aluminium oxide particles by using sandblaster, by using stone point, and high polished with $Opa^{(R)}$ and Lace $motor^{(R)}$. The surface of acrylic resin attached by bacteria was directly touched on the surface of BHI agar, which was incubated. Bacteria colonies formed on BHI agar were counted in accordance with the degree of the surface roughness. Results: 1. The viable cell number of Streptococcus mutans increased on the acrylic resins incubated in BHI broth than in PBS. 2. The viable cell number of Streptococcus mutans increased on the acrylic resins incubated without agitation than with agitation, washed three times than six times, and incubated in broth added with 5% sucrose than without sucrose. 3. When Streptococcus mutans incubated in BHI broth, the number of Streptococcus mutans colonies formed on BHI agar was the largest on the acrylic resins finished with $250{\mu}m$ aluminium oxide particle using sandblaster. But when incubated in BHI broth containing sucrose, the number of colonies formed on that was the largest on the acrylic resins high polished using $Opal^{(R)}$ and Lace $motor^{(R)}$. 4. When Streptococcus sanguis was incubated in BHI broth with or without sucrose, the number of Streptococcus mutans colonies formed on BHI agar was the largest on the acrylic resins finished with $250{\mu}m$ aluminium oxide particle using sandblaster. 5. When Actinomyces viscosus was incubated in BHI broth with or without sucrose, the number of Streptococcus mutans colonies formed on BHI agar was the largest on the acrylic resins high polished using $Opal^{(R)}$ and Lace $motor^{(R)}$. Conclusion: These results indicated that when acrylic resins attached by bacteria were touched on the surface of BHI agar, the number of bacterial colonies formed on the agar was dependent on the bacterial species. Also, the result of this study was showed that increase in the surface roughness and the addition of sucrose increased retention of microbial cells.

• Journal of fish pathology
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• v.27 no.1
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• pp.1-9
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• 2014

The olive flounder, Paralichthys olivaceus is susceptible to viral hemorrhagic septicaemia virus (VHSV) at $15^{\circ}C$ but no mortality at $20^{\circ}C$ even though the virus can grow well in vitro at $20^{\circ}C$. Thus, we designed an experiment to know immune response of olive flounder against VHSV when the host reared at $15^{\circ}C$ or $20^{\circ}C$. cDNA microarray analysis was performed to compare the gene expression patterns of the kidney cells between the host reared at $15^{\circ}C$ or $20^{\circ}C$. The expression of MHC class I, IL-8, myeloperoxidae and endonuclease G-like having function for the antigen presentation and chemokine-factor were up-regulted both the $15^{\circ}C$ and $20^{\circ}C$ during VHSV infection. MHC class II gene existing on antigen-presenting cells and B cell lymphocytes, immunoglobulin (Ig) genes and phagocytosis related genes were down-regulated at $15^{\circ}C$ but highly expressed at $20^{\circ}C$. It can be thought that innate immune related antigen presentation by MHC class I and phagocytosis reaction against VHSV are efficiently occur both the temperature but macrophage or B cell related antigen presentation via MHC class II fails to induce downstream immune reactions (adaptive immunity) to make antibody, and it can be one of the reason that causes high mortality only at $15^{\circ}C$.

• Korean Journal of Pharmacognosy
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• v.47 no.2
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• pp.122-127
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• 2016

Methicillin-Resistant Staphylococcus aureus(MRSA) is a multidrug-resistant(MDR) strain. (+)-Usnic acid(UA) is uniquely found in lichens, and is especially abundant in genera such as Usnea and Cladonia. UA has antimicrobial activity against human and plant pathogens. Therefore, UA may be a good antibacterial drug candidate for clinical development. In search of a natural products capable of inhibiting this multidrug-resistant bacteria, we have investigated the antimicrobial activity of UA against 17 different strains of the bacterium. In this study, the effects of a combination of UA and permeable agents against MRSA were investigated. For the measurement of cell wall permeability, UA with concentration of Ethylenediaminetetraacetic acid(EDTA) was used. In the other hand, Sodium azide($NaN_3$) was used as inhibitors of ATPase. Against the 17 strains, the minimum inhibitory concentrations(MICs) of UA were in the range of $7.81-31.25{\mu}g/ml$. EDTA or $NaN_3$ cooperation against MRSA showed synergistic activity on cell wall. UA and in combination with EDTA and $NaN_3$ could lead to the development of new combination antibiotics against MRSA infection.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.6
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• pp.633-641
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• 2015

Waterborne infectious disease is induced by several pathogenic microbes such as bacteria, viruses and protozoans, and the cases caused by viral infection is currently increasing. Water treatment process could reduce the number of virus in the water, but there were many difficulties to completely remove the virus particles from water. Therefore, the membrane separation technology which was reported to effectively remove pollutants from raw water has attracted increasing attention and demand. Since its efficiency has been introduced, demands for evaluation method toward the membrane filtration process are increasing. However, progression of the method development is slow due to the difficulties in cultivation of several waterborne viruses from animal models or cell culture system. To overcome the difficulties, we used adenovirus, one of the commonly isolated pathogenic waterborne viruses which can grow in cell culture system in vitro. The adenovirus used in this study was identified as human adenovirus C strain. The adenovirus was spiked in the raw water and passed through the microfiltration membrane produced by Econity, a Korean membrane company, and then the viral removal rate was evaluated by real-time PCR. In the results, the amount of virus in the filtered water was decreased approximately by 5 log scale. Because coagulant treatment has been known to reduce filtering function of the membrane by inducing fouling, we also investigated whether there was any interference of coagulant. In the results, we confirmed that coagulant treatment did not show significant interference on microfiltration membrane. In this study, we found that waterborne virus can be effectively removed by membrane filtration system. In particular, here we also suggest that real-time PCR method can rapidly, sensitively and quantitatively evaluate the removal rate of virus. These results may provide a standard method to qualifying membrane filtration processes.

• Journal of fish pathology
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• v.18 no.2
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• pp.167-178
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• 2005

Streptococcus iniae is one of the major bacterial pathogens of cultured olive flounder, Paralichthys olivaceus in Korea. This study was carried out to investigate the interaction between morphological characteristics and immune response such as phagocytosis and serum killing activity. They were differentiated phenotypically into two groups, the viscous colonies and the non-viscous colonies, but the strains in both groups were similar in physiological and biochemical characteristics. Electron microscopic examination of the viscous form revealed thick, electron-dense exopolysaccharide materials surrounding polycationic ferritin-stained cells, while the exopolysaccharide material was absent around the non-viscous form of S. iniae. The viscous type strains were disclosed more virulent than those of non-viscous type for olive flounder. The viscous strains were resistant to normal serum killing activity, while the non-viscous strains were susceptible to bactericidal activity of normal serum from olive flounder. The viscous strains were more resistant to opsonophagocytosis and decreased the chemiluminescence response of head kidney macrophages of olive flounder. All of the tested non-viscous S. iniae strains were efficiently destroyed by the macrophage after phagocytosis. Both the viscous and the non-viscous strains invaded and replicated in cultured fish cell line (CHSE-2l4). This cellular invasion may contribute to the pathogenesis of invasive S. iniae infection.

• Clinical and Experimental Pediatrics
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• v.57 no.3
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• pp.125-134
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• 2014

Purpose: The aim of this study was to characterize Korean patients with Fanconi anemia (FA), which is a rare but very challenging genetic disease. Methods: The medical records of 12 FA patients diagnosed at Chonnam National University Hospital from 1991 to 2012 were retrospectively reviewed. Results: The median age at diagnosis was 6.2 years. All patients showed evidence of marrow failure and one or more physical stigmata. Chromosome breakage tests were positive in 9 out of 11 available patients. The median follow-up duration was 69.5 months. The Kaplan-Meier (KM) survival of all patients was 83.3% at 10 years and 34.7% at 20 years, respectively. Seven patients underwent 9 stem cell transplantations (SCTs). Among them, 5 were alive by the end of the study. Ten-year KM survival after SCT was 71.4% with a median follow-up of 3.4 years. All 5 patients treated with supportive treatment alone died of infection or progression at the median age of 13.5 years, except for one with short followup duration. Acute leukemia developed in 2 patients at 15.4 and 18.1 years of age. Among 6 patients who are still alive, 3 had short stature and 1 developed insulin-dependent diabetes mellitus. Conclusion: We provide information on the long-term outcomes of FA patients in Korea. A nation-wide FA registry that includes information of the genotypes of Korean patients is required to further characterize ethnic differences and provide the best standard of care for FA patients.