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Gyeonggi, South Korea

Jun J.W.,Hellenic Center for Marine Research | Jun J.W.,Seoul National University | Yun S.K.,Seoul National University | Kim H.J.,Seoul National University | And 2 more authors.
Research in Microbiology | Year: 2014

Shigellosis is one of major foodborne pathogens in both developed and developing countries. Although antibiotic therapy is considered an effective treatment for shigellosis, the imprudent use of antibiotics has led to the increase of multiple-antibiotic-resistant Shigella species globally. In this study, we isolated a virulent Podoviridae bacteriophage (phage), pSb-1, that infects Shigella boydii. One-step growth analysis revealed that this phage has a short latent period (15min) and a large burst size (152.63PFU/cell), indicating that pSb-1 has good host infectivity and effective lytic activity. The double-stranded DNA genome of pSb-1 is composed of 71,629bp with a G+C content of 42.74%. The genome encodes 103 putative ORFs, 9 putative promoters, 21 transcriptional terminators, and one tRNA region. Genome sequence analysis of pSb-1 and comparative analysis with the homologous phage EC1-UPM, N4-like phage revealed that there is a high degree of similarity (94%, nucleotide sequence identity) between pSb-1 and EC1-UPM in 73 of the 103 ORFs of pSb-1. The results of this investigation indicate that pSb-1 is a novel virulent N4-like phage infecting S. boydii and that this phage might have potential uses against shigellosis. © 2014 Institut Pasteur. Source


Jun J.W.,Seoul National University | Kim J.H.,Korea Advanced Institute of Science and Technology | Shin S.P.,Seoul National University | Han J.E.,Seoul National University | And 2 more authors.
Research in Microbiology | Year: 2013

Shigellosis is a global health problem, and Shigella flexneri is the major cause of this disease. In this study, we isolated a virulent Siphoviridae bacteriophage (phage), pSf-1, that infects S. flexneri. This phage was isolated from the Han River in Korea and was found to infect S. flexneri, Shigella boydii, and Shigella sonnei. One-step growth analysis revealed that this phage has a short latent period (10min) and a large burst size (86.86PFU/cell), indicating that pSf-1 has good host infectivity and effective lytic activity. The double-stranded DNA genome of pSf-1 is composed of 51,821bp with a G+C content of 44.02%. The genome encodes 94 putative ORFs, 71 putative promoters, and 60 transcriptional terminator regions. Genome sequence analysis of pSf-1 and comparative analysis with the homologous Shigella phage Shfl1 revealed that there is a high degree of similarity between pSf-1 and Shfl1 in 54 of the 94 ORFs of pSf-1. The results of this investigation indicate that pSf-1 is a novel Shigella phage and that this phage might have potential uses against shigellosis. © 2013 Institut Pasteur. Source


Choi N.-Y.,Hanyang University | Choi H.,Hanyang University | Park H.-H.,Hanyang University | Lee E.-H.,Hanyang University | And 4 more authors.
Brain Research | Year: 2014

Hypertension is associated with oxidative stress. Amlodipine besylate (AB) and benidipine hydrochloride (BH), which are Ca2+ antagonists, have been reported to reduce oxidative stress. In this study, we examined the neuroprotective effects of AB and BH on oxidative stress-injured neural stem cells (NSCs), with a focus on the phosphatidylinositol 3-kinase (PI3K) pathway and the extracellular signal-regulated kinase (ERK) pathway. After treatment with H2O2, the viability of NSCs decreased in a concentration-dependent manner; however, co-treatment with AB or BH restored the viability of H2O2-injured NSCs. H2O 2 increased free radical production and apoptosis in NSCs, whereas co-treatment with AB or BH attenuated these effects. To evaluate the effects of AB or BH on the H2O2-inhibited proliferation of NSCs, we performed BrdU labeling and colony formation assays and found that NSC proliferation decreased upon H2O2 treatment but that combined treatment with AB or BH restored this proliferation. Western blot analysis showed that AB and BH increased the expression of cell survival-related proteins that were linked with the PI3K and ERK pathways but decreased the expression of cell death-related proteins. To investigate whether the PI3K and ERK pathways were directly involved in the neuroprotective effects of AB and BH on H2O2-treated NSCs, NSCs were pretreated with the PI3K inhibitor, LY294002, or the ERK inhibitor, FR180204, which significantly blocked the effects of AB and BH. Together, our results suggest that AB and BH restore the H2O2-inhibited viability and proliferation of NSCs by inhibiting oxidative stress and by activating the PI3K and ERK pathways. © 2014 Elsevier B.V. Source


Han J.E.,Seoul National University | Kim J.H.,Seoul National University | Cheresca C.H.,Seoul National University | Shin S.P.,Seoul National University | And 4 more authors.
Research in Microbiology | Year: 2012

Antimicrobial resistance patterns in a collection of 33 motile Aeromonas species were described in this study. Quinolone has been frequently employed for treatment of Aeromonas-related diseases, and prolonged use of antimicrobial compounds has led to development of resistant strains. In a sample of diseased fish and environmental water, we evaluated nalidixic acid (n=19) and ciprofloxacin (n=4) resistance via minimum inhibitory concentration (MIC) assays and the genetic basis was also investigated. Among the isolated Aeromonas spp., 17 strains encoded for chromosomal mutations of quinolone resistance-determining regions (QRDRs) in gyrA, 11 strains encoded for mutations of QRDRs in parC, 1 strain harbored plasmid-mediated quinolone resistance (PMQR) qnrS1-like gene and 4 strains harbored the PMQR qnrS2 gene. Inparticular, the new variant (qnrS1-like) differed from qnrS1 by 6 amino acid substitutions at positions 5 (Asn 5→Arg 5), 120 (Ser 120→Thr 120), 148 (Asn 148→His 148), 206 (Leu 206→Glu 206), 207 (Ile 207→ Leu 207), and 216 (Tyr 216→Phe 216), and the gene was designated qnrS5. These resistant strains may function as reservoirs of quinolone resistance. © 2011 Institut Pasteur. Source


Lee K.-S.,Bundang Jesaeng Hospital | Bae S.-H.,Ajou University | Lee S.H.,Ajou University | Lee J.,Wonkwang University | Lee D.R.,Wonkwang University
Journal of Korean medical science | Year: 2014

This cross-sectional study was performed to investigate the reference values for bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) and the prevalence of osteoporosis in the Korean population by applying domestic reference data. In total, 25,043 Korean adults ≥20 yr of age (11,792 men and 13,251 women) participated in the study. The BMDs of the total hip, femoral neck, and lumbar spine were measured by DXA (Discovery-W, Hologic Inc.), and subjects with a BMD - 2.5 standard deviations or lower than the mean BMD for young adults (20-29 yr old) were considered to have osteoporosis. When applying the new reference values determined in this study from Korean subjects, the overall prevalence of osteoporosis increased in men aged ≥50 yr compared with that provided by the DXA manufacturer from Japanese subjects (12.2% vs. 7.8%, P<0.001) and decreased in postmenopausal women aged ≥50 yr (32.9% vs. 38.7%, P<0.001). According to the findings of this study, use of the reference values provided by the DXA manufacturer has resulted in the underdiagnosis of osteoporosis in Korean men and the overdiagnosis of osteoporosis in Korean women. Our data will serve as valuable reference standards for the diagnosis and management for osteoporosis in the Korean population. Source

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