• Pediatric Infection and Vaccine
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• v.26 no.1
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• pp.1-10
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• 2019

Purpose: We investigated the distribution and antimicrobial resistance of pneumococcal isolates from hospitalized children at Asan Medical Center for recent 4 years, and aimed to recommend proper choice of empirical antibiotics for pneumococcal infection. Methods: From March 2014 to May 2018, children admitted to Asan Medical Center Childrens' Hospital with pneumococcal infection were subjected for evaluation of minimal inhibitory concentration (MIC) for ${\beta}-lactams$ and macrolide antibiotics. Patient's age, underlying disease, gender were retrospectively collected. Using Monte Carlo simulation model and MIC from our study, we predicted the rate of treatment success with amoxicillin treatment. Results: Sixty-three isolates were analyzed including 20.6% (n=13) of invasive isolates, and 79.4% (n=50) of non-invasive isolates; median age were 3.3 years old, and 87.3% of the pneumococcal infections occurred to children with underlying disease. Overall susceptibility rate was 49.2%, 68.2%, and 74.6% for amoxicillin, parenteral penicillin, and cefotaxime respectively. 23.8% and 9.5% of the isolates showed high resistance for amoxicillin, and cefotaxime. Only 4.8% (n=3) were susceptible to erythromycin. Monte Carlo simulation model revealed the likelihood of treatment success was 46.0% at the dosage of 90 mg/kg/day of amoxicillin. Conclusions: Recent pneumococcal isolates from pediatric patients with underlying disease revealed high resistance for amoxicillin and cefotaxime, and high resistance for erythromycin. Prudent choice of antibiotics based on the local data of resistance cannot be emphasized enough, especially in high risk patients with underlying disease, and timely vaccination should be implemented for prevention of the spread of resistant strains.

• Journal of Life Science
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• v.28 no.11
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• pp.1347-1353
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• 2018

The fermentation of non-digestible soy meal can convert polysaccharides into many compounds that have a wide variety of biological functions. Bacillus strains are capable of hydrolyzing non-digestible saccharides, such as melibiose, raffinose, and stachyose, found in soy meal components. A highly active ${\alpha}$-galactosidase (${\alpha}$-d-galactoside galactohydrolase, EC 3.2.1.22) was isolated from a bacterium in a traditional Korean fermented medicinal herb preparation. The isolate, T2-16, was identified as Bacillus coagulans based on its 16S rRNA sequence and biochemical properties, and the strain was named Bacillus coagulans NRR-1207. When incubated in 10%(w/v) skim milk, Bacillus coagulans NRR1207 caused a decrease in the pH of the culture medium, as well as an increase in titratable acidity and viable cell counts. This strain also showed higher activities of ${\alpha}$-galactosidase, ${\beta}$-galactosidase, ${\alpha}$-glucosidase, naphthol-AS-BO-phosphohydrolase, and acid phosphatase when compared to other enzymes. It hydrolyzed oligomeric substrates, such as raffinose and stachyose, and liberated galactose, indicating that the Bacillus coagulans NRR1207 ${\alpha}$-galactosidase hydrolyzed the ${\alpha}$-1,6 glycoside linkage. These results suggest that the decreased stachyose and raffinose contents observed in fermented soy meal are due to this ${\alpha}$-galactosidase activity. Bacillus coagulans NRR1207 therefore has potential probiotic activity and could be utilized in feed manufacturing, as well as for hydrolyzing non-digestible soy meal components.

• Journal of Mushroom
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• v.17 no.3
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• pp.113-118
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• 2019

Oyster mushrooms are an economically important crop, accounting for 35% of the total mushroom production in Korea. In this study, we developed a new cultivar of Pleurotus ostreatus, known as 'Baekseon,' which is characterized by a white pileus with a white stipe. It was bred by mating monokaryons isolated from white mutant oyster mushrooms that were naturally generated from 'Gonji-7ho' and 'Wonhyeong-1ho' at the Mushroom Research Institute, GARES, Korea in 2018. The optimum temperature for mycelial growth on potato dextrose agar medium was approximately $28-31^{\circ}C$, and the optimum temperatures for primordia formation and growth of fruit bodies on sawdust media were $22^{\circ}C$ and $20^{\circ}C$, respectively. The time required for the bottle-cultured mushrooms to complete spawn running, primordia formation, and growth of fruit bodies was 30 days, 4 days, and 4 days, respectively. The fruit bodies were bundle-shaped, the pilei were round type and white, and the stipes were white. The stipes were slender and longer than those of the control ('Miso'). In the productivity test, the yield per bottle was 185 g/1100 mL, which was 45% greater than that of the control ('Miso'). In the farm test, the yield per bottle for Farm A (Pyeongtaek) and Farm B (Yeoju) was 184 g/1100 mL and 178 g/850 mL, respectively. With regard to the physical properties of fruit bodies, the springiness, cohesiveness, gumminess, and brittleness of stipe tissue were 80%, 57%, 720 g, and 57 kg, respectively. These values were lower than those of the control ('Miso'). To test the shelf life, the fruit bodies were wrapped with antifogging film and stored at $4^{\circ}C$ for 28 days and then at room temperature for 4 days; such conditions were sufficient for maintaining edibility.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.3
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• pp.360-369
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• 2019

Cadherins are essential transmembrane proteins that promote cell-cell adhesion and maintain the corpus luteum structure in the ovary. This study examined the influence of prostaglandin F2 alpha ($PGF2{\alpha}$) on E-cadherin, N-cadherin, and adhesion in luteal theca cells (LTCs). The luteal cells were isolated from the mid-phase corpus luteum, and the LTCs were cultured separately from the luteal heterogeneous cells according to the morphology of the mesenchymal cells and to determine if steroidogenic and endothelial cells of LTCs, 3beta-hydroxysteroid dehydrogenase ($3{\beta}$-HSD), and vascular endothelial growth factor receptor 2 (VEGFR2) mRNA were used. The LTCs were then incubated in the culture medium supplemented with 0.01, 0.1, and 1.0 mM $PGF2{\alpha}$ for 24 h, and the E-cadherin and N-cadherin proteins in the LTCs were detected by confocal laser scanning microscopy. The results revealed $3{\beta}$-HSD mRNA expression in the LTC but no VEGF2R mRNA expression. The E-cadherin and N-cadherin proteins of the LTCs were damaged in the 0.01, 0.1, and 1.0 mM $PGF2{\alpha}$ treatment groups, and the expression of the N-cadherin protein was reduced significantly in 0.01 mM $PGF2{\alpha}$ compared to the 0 mM $PGF2{\alpha}$ treatment groups (P<0.05). In addition, the number of attached LTCs were significantly lower in the 0.01 mM $PGF2{\alpha}$ treatment group than in the 0 mM $PGF2{\alpha}$ treatment group (P<0.05). In conclusion, $PGF2{\alpha}$ affected the disruption of cadherin proteins and cell adhesion in LTCs. These results may help better understand the cadherin and adhesion mechanism during corpus luteum regression in the ovary.

• Korean Journal of Microbiology
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• v.55 no.3
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• pp.234-241
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• 2019

An intensive interaction between yeasts and insects has highlighted their relevance for attraction to food and for the insect's development and behavior. Yeast associated in the gut of insects secretes cellulase which aided in the food digestion (cellulose degradation). Three strains of cellulose-degrading yeast were isolated from the gut of adult grasshoppers collected in Gyeonggi Province, South Korea. The strains $ON22^T$, $G10^T$, and $G15^T$, showed positive cellulolytic activity in the carboxymethyl cellulose (CMC)-plate assay. The phylogenetic tree based on sequence analysis of D1/D2 domains of the large subunit rRNA gene and the internal transcribed spacer (ITS) regions revealed that the strains $ON22^T$ (100 and 98.4% sequence similarities in D1/D2 domains and ITS) and $G10^T$ (99.8 and 99.5% in D1/D2 domain and ITS region) were most closely related to the species Moesziomyces aphidis JCM $10318^T$; $G15^T$ (100% in D1/D2 domains and ITS) belongs to the species Moesziomyces antarcticus JCM $10317^T$, respectively. Morphology and biochemical test results are provided in the species description. Cellulase with its massive applicability has been used in various industrial processes such as biofuels like bioethanol productions. Therefore, this is the first report of the cellulolytic yeast strains $ON22^T$, $G10^T$, and $G15^T$ related to the genus Moesziomyces in the family Ustilaginaceae (Ustilaginales), in Korea.

• Research in Plant Disease
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• v.25 no.3
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• pp.108-113
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• 2019

Almost 30% of arable lands of North Korea are covered with paddy rice. In rice cultivation of North Korea, rice blast disease is the most important fungal disease and bacterial leaf blight is the most important bacterial disease. Seven North Korean rice cultivars had been tested for the disease resistance against rice blast pathogen, Magnaporthe oryzae and bacterial leaf blight pathogen, Xanthomonas oryzae pv. oryzae. The responses of seven cultivars against 17 different M. oryzae races from South Korea had been quite different. Among seven cultivars, Giljoo1ho was very resistant to all 18 different M. oryzae isolates from South Korea, nevertheless KI or KJ. Pyungdo5ho was very susceptible, it showed susceptible responses to 8 out of 10 KI races and 7 out of 8 KJ races of M. oryzae isolated in South Korea. However, the response to bacterial leaf blight was different from the response to rice blast pathogen. Gijoo1ho, Wonsan69ho, Onpo1ho, and Pyungdo15ho were susceptible to KXO42 (K1) and KXO90 (K2), respectively. Pyungdo5ho was resistant to KXO85 (K1) and KXO19 (K3), and Pyungyang21ho was resistant to K1 races. Based on these results, Giljoo1ho can be a good resource for the breeding of resistant rice cultivar against M. oryzae isolates from South Korea.

• Journal of Life Science
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• v.29 no.10
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• pp.1062-1070
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• 2019

A components of garlic (Allium sativum) have anti-proliferative effects against various types of cancer. We aimed to investigate the capacity of garlic compounds to anti-tumor on a various cancer cell lines. Fractionation of garlic extract, guided by antiproliferative activity against human gastric cancer (AGS) cells, has resulted in the isolation of N-benzyl-N-methyldecan-1-amine (NBNMA). We investigated the effect of newly isolated NBNMA from garlic cloves on the inhibition of the growth of CT-26, AGS, HepG2, HCT-116, MCF7, B16F10, and Sarcoma-180 cells for in vitro and CT-26 colon carcinoma cells in vivo. NBNMA exhibited an antiproliferative effect in CT-26 cells by apoptotic cell death. NBNMA exhibited down-regulation of anti-apoptotic Bcl-2 proteins and up-regulation of apoptotic Bad protein expression in western blot analyses. In addition, NBNMA meagre activated caspase 3 and caspase 9, initiator caspases of the extrinsic and intrinsic pathways of apoptosis. NBNMA treatment at a dose of 10 mg/kg for 21 days in experimental mice implanted with tumors resulted in significant reduction of the tumor weight (43%). NBNMA exhibited both in vitro and in vivo anticancer activity. These results indicate that NBNMA has promising potential to become a novel anticancer agent from garlic cloves for the treatment of colon carcinoma cancer.

• Journal of Life Science
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• v.29 no.8
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• pp.861-870
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• 2019

This study was undertaken to establish optimum medium compositions for cost-effective mannitol production by Leuconostoc mesenteroides SRCM201425 isolated from kimchi. L. mesenteroides SRCM21425 from kimchi was selected for efficient mannitol production based on fructose analysis and identified by its 16S rRNA gene sequence, as well as by carbohydrate fermentation pattern analysis. To enhance mannitol production by L. mesenteroides SRCM201425, the effects of carbon, nitrogen, and mineral sources on mannitol production were first determined using Plackett-Burman design (PBD). The effects of 11 variables on mannitol production were investigated of which three variables, fructose, sucrose, and peptone, were selected. In the second step, each concentration of fructose, sucrose, and peptone was optimized using a central composite design (CCD) and response surface analysis. The predicted concentrations of fructose, sucrose, and peptone were 38.68 g/l, 30 g/l, and 39.67 g/l, respectively. The mathematical response model was reliable, with a coefficient of determination of $R^2=0.9185$. Mannitol production increased 20-fold as compared with the MRS medium, corresponding to a mannitol yield 97.46% when compared to MRS supplemented with 100 g/l of fructose in flask system. Furthermore, the production in the optimized medium was cost-effective. The findings of this study can be expected to be useful in biological production for catalytic hydrogenation causing byproduct and additional production costs.

• Korean Journal of Microbiology
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• v.54 no.4
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• pp.384-397
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• 2018

The aim of this study is to screen the strains of Bacillus spp. possessing safety, probiotic activity, and so on, which can be utilized as probiotic resource for using the feed and supplement food of companion animal. About 300 isolates were isolated from traditional Korean sauces, four isolates that did not have or produce the six kinds of B. cereus type vomiting and diarrhea toxin genes, ${\beta}$-hemolytic, and three kinds of carcinogenic enzymes were selected. Antibiotic gene retention, cell surface hydrophobicity, antibiotic sensitivity, and glucose utilization were analyzed for four isolates, and finally SRCM 100731 was selected. SRCM 100731 was named as Bacillus amyloliquefaciens SRCM 100731 16S rRNA sequencing analysis, and carried out optimization of cell growth for industrial applications such as pet food and feed. The effects of 14 different components on cell growth were investigated and three significant positive factors, molasses, sodium chloride, and potassium chloride were selected as the main factors based on a Plackett-Burman design. In order to find out optimal concentration on each constituent, we carried out central composite design. The predicted optimized concentrations were 7% molasses, 1.1% sodium chloride, 0.5% potassium chloride. Finally, an overall about 7-fold increase in dry cell weight yield ($12.6625{\pm}0.0658g/L$) was achieved using the optimized medium compared with the non-optimized medium ($1.8273{\pm}0.0214g/L$). This research is expected to be highly utilized in the growing pet industry by establishing optimal cultivation conditions for industrial application as well as screening Bacillus amyloliquefaciens SRCM 100731 as probiotic resource for companion animal.

• Journal of Life Science
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• v.29 no.1
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• pp.76-83
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• 2019

In this study, the optimal growth and poly(3-hydroxybutyrate) (PHB) biosynthesis of Pseudomonas sp. EML2 were established using waste frying oil (WFO) as a cheap carbon source. The fatty acid composition of WFO and fresh frying oil (FFO) were analyzed by gas chromatography. The unsaturated and saturated fatty acid contents of the FFO were 82.6% and 14.9%, respectively. These contents changed in the WFO. The compositional change in the unsaturated fatty acid content in the WFO was due to a change in its chemical and physical properties resulting from heating, an oxidation reaction, and hydrolysis. The maximum dry cell weight (DCW) and PHB yield (g/l) of the isolated strain Pseudomonas sp. EML2 were confirmed under the following culture conditions: 30 g/l of WFO, 0.5 gl of $NH_4Cl$, pH 7, and $20^{\circ}C$. Based on this, the growth and PHB yield of Pseudomonas sp. EML2 were confirmed by 3 l jar fermentation. After the cells were cultured in 30 g/l of WFO for 96 h, the DCW, PHB content, and PHB yield of Pseudomonas sp. EML2 were 3.6 g/l, 73 wt%, and 2.6 g/l, respectively. Similar results were obtained using 30 g/l of FFO as a carbon source control. Using the FFO, the DCW, PHB content, and PHB yield were 3.4 g/l, 70 wt%, and 2.4 g/l, respectively. Pseudomonas sp. EML2 and WFO may be a new candidate and substrate, respectively, for industrial production of PHB.