Antibiotic susceptibility and resistance of Streptococcus iniae and Streptococcus parauberis isolated from olive flounder (Paralichthys olivaceus)

Park, Y.K.,Nho, S.W.,Shin, G.W.,Park, S.B.,Jang, H.B.,Cha, I.S.,Ha, M.A.,Kim, Y.R.,Dalvi, R.S.,Kang, B.J.,Jung, T.S. Elsevier Scientific Pub. Co 2009 Veterinary microbiology Vol.136 No.1

The rates of antibiotic susceptibility and resistance were investigated in Streptococcus iniae and Streptococcus parauberis isolates obtained from diseased olive flounders (Paralichthys olivaceus) collected from fish farms in Jeju Island, Korea. Isolates of S. iniae (n=65) were susceptible to cefotaxime, erythromycin, ofloxacin, penicillin, tetracycline and vancomycin, as demonstrated by the minimum inhibitory concentration (MIC) test. Isolates of S. parauberis (n=86) were highly resistant to erythromycin (58% of the 86 isolates tested) and tetracycline (63% of the 86 isolates tested). Fifty-four isolates of tetracycline-resistant S. parauberis contained the tet(M/O/S) genes, of which 39 and 12 isolates contained the tet(M) and tet(S) genes, respectively, whereas 3 isolates contained both the tet(M) and tet(S) genes. Among the erythromycin-resistant isolates of S. parauberis (n=50) only 14 contained the erm(B) gene. These results suggest that the tet(S) and erm(B) genes of S. parauberis are involved in the acquisition of high-level resistance to erythromycin and tetracycline. Our findings reveal a high rate of antibiotic resistance among strains of S. parauberis and emphasize the need to develop an appropriate vaccine to reduce the use of antibiotics.

Characteristics of Adherence and Invasion of Staphylococcus lugdunensis to Human Oral Epithelial Cells

Cha, J. D.,Lee, S. H.,Jung, K. Y.,Lim, D.S.,Woo, W. H.,Kim, K. J. Korean Academy of Oral Biology and the UCLA Dental 1999 International Journal of Oral Biology Vol.24 No.2

Staphulococcus lugdunensis is one of the most common pathogens in coagulase-negative staphylococci. Adhesion and invasion of S. lugdunensis to oral epithelial cells were demonstrated by recovery of viable organisms from gentamicin-treated KB cells, human oral epidemoid carcinoma cells. Adhesion was found to be time dependent and increased linearly with increasing number of bacteria added (10^3-10^5 CFU/well). Bacterial adhesion to the KB cells occurred via a cytochalasin B- and D-insensitive process. To clarify the time point and characteristics of S. lugdunensis invasion of KB cells, bacteria (10^4 CFU/well) were cocultered for several different times (1-5 hr) with or without cytochalasin B (1 ㎍/ml), follwed by additional coculture for 2hr in the presence of gentamicin (100㎍/ml). No bacteria were recovered at 2 hr, but a few colonies were detected after 3 hr of coculture. In addition, cytochalasin B also did not affect invasion of S. lugdunensis into KB cells. The data obtained here demonstrate that S. lugdunensis can adhere to the KB cells via a cytoskeletal actin protein-independent process; however its invasion through the cellular membrane is unclear. These data suggest a tissue-specific characteristic of pathogenesis for S. lugdunensis in in vivo.

Prevalence and antimicrobial susceptibility of Salmonella isolates in Pekin ducks from South Korea

Cha, S.Y.,Kang, M.,Yoon, R.H.,Park, C.K.,Moon, O.K.,Jang, H.K. Pergamon Press 2013 Comparative immunology, microbiology and infectiou Vol.36 No.5

An investigation was carried out to determine the prevalence and antibiotic resistance of Salmonella serotypes at South Korean duck farms. A total of 7119 samples collected from 72 duck farms in five provinces were examined from 2011 to 2012. The overall prevalence of Salmonella serotypes was 43.4% (69/159) in duck flocks from 65.2% (47/72) of the duck farms. Eighty-five strains were isolated from 69 duck flocks. Three serotypes of Salmonella enterica were identified such as S. Typhimurium (39/85), S. Enteritidis (44/85), and S. London (2/85). The prevalence of Salmonella infection decreased significantly in 3-week-old ducks compared to that in 1-week-old ducks (P<0.05). All isolates except one were resistant to at least one antimicrobial and 27% of the isolates were resistant to 5-16 antimicrobials. Our findings provide baseline information on the degree of Salmonella infection and distribution of Salmonella serotypes in ducks and indicate that ducks should be considered an important source of foodborne pathogens.

Optical Properties and Glass-forming Region of the K2O-Sm2O3-TeO2 Glass System

K. S. Hong,Y. J. Cha,M. G. Ha,최세용,J. P. Kim,B. S. Lee,정의덕,김현규,P. H. Borse 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.9

The optical properties and the glass-forming region of the K2O-Sm2O3-TeO2 glass system arestudied. In the K2O-Sm2O3-TeO2 system, only the 5K2O-5Sm2O3-90TeO2 composition gives atransparent glass. The refractive index, n, and the optical band-gap energy, Eg, of the 5K2O-5Sm2O3-90TeO2 glass are n = 2.04 ± 0.003 and Eg = 3.2 eV, respectively. A single Sm2Te6O15phase is found to be formed by a two-step thermal treatment process at 370 C for 5 h and 390 Cfor 5 h. This is the first report on the crystallization and the preparation of the K2O-Sm2O3-TeO2glass system.

Role of conserved Met112 residue in the catalytic activity and stability of ketosteroid isomerase

Cha, H.J.,Jang, D.S.,Jeong, J.H.,Hong, B.H.,Yun, Y.S.,Shin, E.J.,Choi, K.Y. Elsevier Science 2016 Biochimica et biophysica acta. Proteins and proteo Vol.1864 No.10

<P>Ketosteroid isomerase (3-oxosteroid Delta(5)-Delta(4)-isomerase, KSI) from Pseudomonas putida catalyzes allylic rearrangement of the 5,6-double bond of Delta(5)-3-ketosteroid to 4,5-position by stereospecific intramolecular transfer of a proton. The active site of KSI is formed by several hydrophobic residues and three catalytic residues (Tyr14, Asp38, and Asp99). In this study, we investigated the role of a hydrophobic Met112 residue near the active site in the catalysis, steroid binding, and stability of KSI. Replacing Met112 with alanine (yields M112A) or leucine (M112L) decreased the k(cat) by 20- and 4-fold, respectively. Compared with the wild type (WT), M112A and M112L KSIs showed increased K-D values for equilenin, an intermediate analogue; these changes suggest that loss of packing at position 112 might lead to unfavorable steroid binding, thereby resulting in decreased catalytic activity. Furthermore, M112A and M112L mutations reduced melting temperature (T-m) by 6.4 degrees C and 2.5 degrees C, respectively. These changes suggest that favorable packing in the core is important for the maintenance of stability in KSI. The M112K mutation decreased k(cat) by 2000-fold, compared with the WT. In M112K KSI structure, a new salt bridge was formed between Asp38 and Lys112. This bridge could change the electrostatic potential of Asp38, and thereby contribute to the decreased catalytic activity. The M112K mutation also decreased the stability by reducing T-m by 4.1 degrees C. Our data suggest that the Met112 residue may contribute to the catalytic activity and stability of KSI by providing favorable hydrophobic environments and compact packing in the catalytic core. (C) 2016 Published by Elsevier B.V.</P>

Characterization of glycosyl hydrolase family 3 β-N-acetylglucosaminidases from Thermotoga maritima and Thermotoga neapolitana

Choi, K.H.,Seo, J.Y.,Park, K.M.,Park, C.S.,Cha, J. Society for Bioscience and Bioengineering, Japan ; 2009 Journal of bioscience and bioengineering Vol.108 No.6

The genes encoding β-N-acetylglucosaminidase (nagA and cbsA) from Thermotoga maritima and Thermotoga neapolitana were cloned and expressed in Escherichia coli in order to investigate whether Thermotoga sp. is capable of utilizing chitin as a carbon source. NagA and CbsA were purified to homogeneity by HiTrap Q HP and Sephacryl S-200 HR column chromatography. Both enzymes were homodimers containing a family 3 glycoside hydrolase (GH3) catalytic domain, with a monomer molecular mass of 54 kDa. The optimal temperatures and pHs for the activities of the β-N-acetylglucosaminidases were found to be 65-75 <SUP>o</SUP>C and 7.0-8.0, respectively. Both enzymes hydrolyzed chitooligomers such as di-N-acetylchitobiose and tri-N-acetylchitotriose, and synthetic substrates such as p-nitrophenyl-β-d-glucose (pNPGlc), p-nitrophenyl N-acetyl β-d-glucosamine (pNPGlcNAc), p-nitrophenyl di-N-acetyl β-d-chitobiose (pNPGlcNAc<SUB>2</SUB>) and p-nitrophenyl tri-N-acetyl β-d-chitotriose (pNPGlcNAc<SUB>3</SUB>). However, the enzymes had no activity against p-nitrophenyl-β-d-galactose (pNPGal) and p-nitrophenyl N-acetyl β-d-galactosamine (pNPGalNAc) or highly polymerized chitin. The k<SUB>cat</SUB> and K<SUB>m</SUB> values were determined for pNPGlcNAc, pNPGlcNAc<SUB>2</SUB> and pNPGlcNAc<SUB>3</SUB>. The k<SUB>cat</SUB>/K<SUB>m</SUB> value for pNPGlcNAc was the highest among three synthetic substrates. NagA and CbsA initially hydrolyzed p-nitrophenyl substrates to give GlcNAc, suggesting that the enzymes have exo-activity with chitin oligosaccharides from the non-reducing ends, like other β-N-acetylglucosaminidases. However, NagA and CbsA can be distinguished from other GH3-type β-N-acetylglucosaminidases in that they are highly active against di-N-acetylchitobiose. Thus, the present results suggest that the physiological role of both enzymes is to degrade the chitooligosaccharides transported through membrane following hydrolysis of chitin into β-N-acetylglucosamine to be further metabolized in Thermotoga sp.

Korean red ginseng extract rejuvenates testicular ineffectiveness and sperm maturation process in aged rats by regulating redox proteins and oxidative defense mechanisms

Kopalli, S.R.,Hwang, S.Y.,Won, Y.J.,Kim, S.W.,Cha, K.M.,Han, C.K.,Hong, J.Y.,Kim, S.K. Pergamon Press ; Elsevier Science Ltd 2015 Experimental Gerontology Vol.69 No.-

Distortion of intracellular oxidant and antioxidant balances appears to be a common feature that underlies in age-related male sexual impairment. Therefore regulating oxidative defense mechanisms might be an ideal approach in improving male sexual dysfunctions. In the present study, the effect of Korean red ginseng aqueous extract (KRG) on age-induced testicular dysfunction in rats was investigated. KRG (200mg/kg) mixed with regular pellet diet was administered orally for six months and the morphological, spermatogenic and antioxidant enzyme status in testis of aged rats (18months) were evaluated. Data indicated a significant change in morphology and decrease in spermatogenesis-related parameters in aged rats (AC) compared with young rats (YC). Sperm number, germ cell count, Sertoli cell count and Sertoli cell index were significantly (p<0.05) restored in KRG-treated aged rat groups (G-AC). Further the increased lipid peroxidation as measured by malondialdehyde (p<0.05), and altered enzymatic (superoxide dismutase, glutathione peroxidase, glutathione S-transferase, glutathione reductase and catalase) and non-enzymatic (reduced glutathione, ascorbic acid and α-tocopherol) antioxidants (p<0.05) were attenuated by KRG treatment in aged rats to near normal levels as in YC groups. Furthermore, proteomic analysis demonstrated differential expression of selected proteins such as phosphatidylinositol transfer protein, fatty acid binding protein-9, triosephosphate isomerase-1 and aldehyde (aldose) reductase-1in aged rats was significantly (p<0.05) protected by KRG treatment. In conclusion, long-term administration of KRG restored aging-induced testicular ineffectiveness in rats by modulating redox proteins and oxidative defense mechanisms.

시뮬레이터 연계용 교육, 훈련 Mimic Board 시스템 개발

차승태(S.T Cha),김태균(T.K Kim),최준호(J.H Choi),김창곤(C.K Kim),이철균(C.K Lee) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.7

A new type of simulation training system for power system operation is presented in this paper. It is based on transmission mimic board, double screen PC, mimic control panel, and real-time digital simulator, KEPS. The operating simulation includes the simulations of the control panel interface and the simulator. The mimic board displays transmission network summary information using a software view of the hardware based mimic board. The symbols, numbers and colors layout exactly match those of the KEPS draft case to provide operators a familiar and effective starting point. This paper describes the development of an innovative training system, utilizing the benefits of 3 dimension visualization s/w and communication-control s/w to create the appropriate operational environment and allow simulation of various power system operations without the restrictions of other training methods. Experiences gained in developing concepts and meeting considerable s/w challenges are outlined, and the potential of the simulator for future operations training discussed.

Suppression of -N-acetylglucosaminidase in the N-glycosylation pathway for complex glycoprotein formation in Drosophila S2 cells

Kim, Y. K.,Kim, K. R.,Kang, D. G.,Jang, S. Y.,Kim, Y. H.,Cha, H. J. Oxford University Press 2009 Glycobiology Vol.19 No.3

<P>Most insect cells have a simple N-glycosylation process and consequently paucimannosidic or simple core glycans predominate. Previously, we have shown that paucimannosidic N-glycan structures are dominant in Drosophila S2 cells. It has been proposed that beta-N-acetylglucosaminidase (GlcNAcase), a hexosaminidase in the Golgi membrane which removes a terminal N-acetylglucosamine (GlcNAc), might contribute to simple N-glycosylation in several insects and insect-derived cells except S2 cells. In the present work, we investigated the substantial effects of GlcNAcase on N-glycan patterns in Drosophila S2 cells using two GlcNAcase suppression strategies: an mRNA-targeting approach using RNA interference (RNAi) and a protein-targeting approach using the specific chemical inhibitor 2-acetamido-1,2-dideoxynojirimycin (2-ADN). Using high-performance liquid chromatography (HPLC) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analyses, we found that the N-glycosylation patterns of human erythropoietin (hEPO) secreted by stably transfected S2 cells were more complex following GlcNAcase suppression, which generated N-glycan structures with a terminal GlcNAc and/or galactose. These data demonstrate that GlcNAcase may be an important factor in the formation of paucimannosidic core N-glycans in Drosophila S2 cells and suggest that it may be possible to express complex glycoproteins in engineered Drosophila S2 cells by suppressing GlcNAcase in the N-glycosylation pathway.</P>

Synthesis and characterization of macrocyclic nickel(II) complexes with α-methylbenzyl groups as chiral pendants

Han, J.H.,Cha, M.J.,Kim, B.G.,Kim, S.K.,Min, K.S. Elsevier 2008 Inorganic chemistry communications Vol.11 No.7

Novel nickel(II) hexaaza macrocyclic complexes, [Ni(L<SUP>R,R</SUP>)](ClO<SUB>4</SUB>)<SUB>2</SUB> (1) and [Ni(L<SUP>S,S</SUP>)](ClO<SUB>4</SUB>)<SUB>2</SUB> (2), containing chiral pendant groups have been synthesized by an efficient one-pot template condensation and characterized (L<SUP>R,R/S,S</SUP>=1,8-di((R/S)-α-methylbenzyl)-1,3,6,8,10,13-hexaazacyclotetradecane). The crystal structures of 1 and 2 were determined by single-crystal X-ray analysis. Each complex has a square-planar coordination environment for the nickel(II) ion, and is either an R or an S enantiomorph depending on the pendant groups. The circular dichroism spectrum of 1 showed a negative, positive and negative peak at 345, 440, and 492nm, respectively, and that of 2 exhibited an enantiomeric pattern.