Characterization of the Streptococcus pneumoniae BgaC Protein as a Novel Surface β-Galactosidase with Specific Hydrolysis Activity for the Galβ1-3GlcNAc Moiety of Oligosaccharides

Jeong, Jae Kap,Kwon, Ohsuk,Lee, Yun Mi,Oh, Doo-Byoung,Lee, Jung Mi,Kim, Seonghun,Kim, Eun-Hye,Le, Tu Nhat,Rhee, Dong-Kwon,Kang, Hyun Ah American Society for Microbiology 2009 Journal of Bacteriology Vol.191 No.9

<B>ABSTRACT</B><P><I>Streptococcus pneumoniae</I> is a causative agent of high morbidity and mortality. Although sugar moieties have been recognized as ligands for initial contact with the host, only a few exoglycosidases have been reported to occur in <I>S. pneumoniae</I>. In this study, a putative β-galactosidase, encoded by the <I>bgaC</I> gene of <I>S. pneumoniae</I>, was characterized for its enzymatic activity and virulence. The recombinant BgaC protein, expressed and purified from <I>Escherichia coli</I>, was found to have a highly regiospecific and sugar-specific hydrolysis activity for the Galβ1-3-GlcNAc moiety of oligosaccharides. Interestingly, the BgaC hydrolysis activity was localized at the cell surface of <I>S. pneumoniae</I>, indicating that BgaC is expressed as a surface protein although it does not have a typical signal sequence or membrane anchorage motif. The surface localization of BgaC was further supported by immunofluorescence microscopy analysis using an antibody raised against BgaC and by a reassociation assay with fluorescein isothiocyanate-labeled BgaC. Although the <I>bgaC</I> deletion mutation did not significantly attenuate the virulence of <I>S. pneumoniae</I> in vivo, the <I>bgaC</I> mutant strain showed relatively low numbers of viable cells compared to the wild type after 24 h of infection in vivo, whereas the mutant showed higher colonization levels at 6 and 24 h postinfection in vivo. Our data strongly indicate for the first time that <I>S. pneumoniae bgaC</I> encodes a surface β-galactosidase with high substrate specificity that is significantly associated with the infection activity of pneumococci.</P>

Biological and Genetic Characterization of Canine Distemper Virus Vaccine Candidate Named as CD1901-100

Dong-Kun Yang,Yu-Ri Park,Ha-Hyun Kim,Eun-Ju Kim,Hye Jeong Le,현방훈 대한미생물학회 2022 Journal of Bacteriology and Virology Vol.52 No.2

Canine distemper virus (CDV) infections cause high morbidity and mortality in dogs. Changes in the molecular biological characteristics of the Korean CDV strain over multiple cell passages have not been reported. We investigated the biological and g enetic characteristics o f CD19 01-100 for u se a s an inactivated vaccine strain. Vero cells expressing the dog nectin-4 gene (Vero/dNectin-4 cells) were used to adapt CD1901, which was passaged 100 times in four types of cells. We assessed the cytopathic effects and used immunofluorescence assays to identify biological features of CD1901 and CD1901-100. Seven types of cells were used to explore the tropisms of the two CDV strains. The genetic analyses were based on whole-genome sequencing data. Vero cells expressing dog signaling lymphocyte activation molecule were infected with the two CDV strains and showed different cytopathic effects and fluorescence properties. CD1901-100 attained the highest viral titer of 106.5 TCID50/mL at 4 days post-inoculation; the overall highest virus titer of 107.0 TCID50/mL was that after growth in Vero/dNectin-4 cells. CD1901-100 exhibited 25 nucleotide mutations and 15 amino acid substitutions in six structural proteins compared to the CD1901 sequences. Of the six proteins, the F protein had the highest number of amino acid replacements (5/663, 0.75%). We constructed a Vero/dNectin-4 cell line and passaged CD1901 100 times in four types of cells. CD1901-100 propagated well in Vero/dNectin-4 cells. This will aid the development of an inactivated CDV vaccine.

High-Performance Control of Three-Phase Four-Wire DVR Systems using Feedback Linearization

Jeong, Seon-Yeong,Nguyen, Thanh Hai,Le, Quoc Anh,Lee, Dong-Choon The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.1

Power quality is a critical issue in distribution systems, where a dynamic voltage restorer (DVR) is commonly used to mitigate the voltage disturbances for loads. This paper deals with a nonlinear control for the three-phase four-wire (3P-4W) DVR under a grid voltage unbalance and nonlinear loads in the distribution system, where a novel control scheme based on the feedback linearization technique is proposed. Through feedback linearization, a nonlinear model of a DVR with a PWM voltage-source inverter (VSI) and LC filters is linearized. Then, the controller design of the linearized model is performed by applying the linear control theory, where the load voltages are kept constant by controlling the d-q-0 axis components of the DVR output voltages. To keep the load voltage unchanged, an in-phase compensation strategy is employed, where the load voltages are recovered to be the same as the previous voltage without a change in the magnitude. With this strategy, the performance of the DVR becomes faster and more stable even under unbalanced source voltages and nonlinear loads. The validity of the proposed control strategy has been verified by simulation and experimental results.

Analysis of Eleutherosides B and E in Acanthopanax divaricatus and A. koreanum by Different Fertilizer Ratio

Jeong Min Lee,Dong-Gu Lee,Sunghun Cho,Jung Jong Lee,Myoung-Hee Lee,Sanghyun Lee 한국육종학회 2014 한국육종학회 심포지엄 Vol.2014 No.07

Acanthopanax species is known commonly as Siberian ginseng, touch-me-not, devil’s shrub, prickly eleutherococc, eleutherococc and wild pepper. A diverse group of chemical compounds isolated from Acanthopanax species was named ‘eleutherosides’. Among eleutherosides, eleutherosides B and E were widely known in Acanthopanax species. Acanthopanax species are cultivated and grow wild in a various area of Korea and have a variety of pharmacological effects. But, there are a lot of difficulties on producing excellent Acanthopanax species, according to the cultivated method is different pharmacological ingredients. This study, therefore, analyzed eleutherosides B and E in A. divaricatus and A. koreanum by different fertilizer ratio using HPLC. We will be investigated a high content of eleutherosides B and E by different fertilizer ratio and suggest an efficient fertilizer ratio of A. divaticatus and A. koreanum. All samples of A. divaricatus and A. koreanum were collected at Yeongcheon Agricultural Technology & Extension Center, Yeongcheon, Korea. The sample was prepared by upper and lower parts. The fertilizer ratio are N-P-K(10.5-8.5-8.5: 50 kg/10a), 2N-P-K (21-8.5-8.5: 50 kg/10a), N-2P-K (10.5-17-8.5: 50 kg/10a), N-P-2K (10.5-8.5-17: 50 kg/10a), and 2N-2P-2K (21-17-17: 50 kg/10a), respectively. To analyze eleutherosides B and E, 5 g of A. divaricatus and A. koreanum was extracted with 50% MeOH (3 × 100 ml) by reflux and evaporated in vacuo. The residue was dissolved in 1 ml of MeOH. The resulting solution was used for HPLC analysis. HPLC separation of eleutherosides B and E for qualitative and quantitative analysis was performed using a reverse phase system. A Discovery®C18 (4.6 × 250 mm, 5 μm) column was used with a mobile phase that consisted of water and acetonitrile. A gradient solvent system of water and acetonitrile (90:10 to 70:30 for 20 min) was used for the elution program. UV detection was conducted at 350 nm. The injection volume was 10 μl and the flow rate was 1 ml/min. All injections were performed in triplicate. The different fertilizer ratio yielded total eleutherosides B and E contents of 4.417-6.905 and 3.652-7.227 mg/g in the upper and lower parts of A. divaricatus, respectively. In A. koreanum, the total eleutherosides B and E contents were 4.591-10.108 and 3.834-9.079 mg/g in the upper and lower parts, respectively. The best conditions to increase eleutherosides B and E content in A. divaricatus was determined to be with N-2P-K fertilizer ratio, on the other hand, in A. koreanum was 2N-2P-2K fertilizer ratio.

Poster Session : Cell Adhesion and Migration ; Cytokine modulation via actin polymerization and ClpL during initial stage of Streptococcus pneumoniae infection

( Le Nhat Tu ),( Hye Yoon Jeong ),( Hyog Young Kwon ),( Kyung Tae Chung ),( Dong Kwon Rhee ) 한국생화학분자생물학회 (구 한국생화학회) 2007 생화학분자생물학회 춘계학술발표논문집 Vol.2007 No.-

PICOT Inhibits Cardiac Hypertrophy and Enhances Ventricular Function and Cardiomyocyte Contractility

Jeong, Dongtak,Cha, Hyeseon,Kim, Eunyoung,Kang, Misuk,Yang, Dong Kwon,Kim, Ji Myoung,Yoon, Pyoung Oh,Oh, Jae Gyun,Bernecker, Oliver Y.,Sakata, Susumu,Thu, Le Thi,Cui, Lei,Lee, Young-Hoon,Kim, Do Han,W Grune & Stratton 2006 Circulation research Vol.99 No.3

<P>Multiple signaling pathways involving protein kinase C (PKC) have been implicated in the development of cardiac hypertrophy. We observed that a putative PKC inhibitor, PICOT (PKC-Interacting Cousin Of Thioredoxin) was upregulated in response to hypertrophic stimuli both in vitro and in vivo. This suggested that PICOT may act as an endogenous negative feedback regulator of cardiac hypertrophy through its ability to inhibit PKC activity, which is elevated during cardiac hypertrophy. Adenovirus-mediated gene transfer of PICOT completely blocked the hypertrophic response of neonatal rat cardiomyocytes to enthothelin-1 and phenylephrine, as demonstrated by cell size, sarcomere rearrangement, atrial natriuretic factor expression, and rates of protein synthesis. Transgenic mice with cardiac-specific overexpression of PICOT showed that PICOT is a potent inhibitor of cardiac hypertrophy induced by pressure overload. In addition, PICOT overexpression dramatically increased the ventricular function and cardiomyocyte contractility as measured by ejection fraction and end-systolic pressure of transgenic hearts and peak shortening of isolated cardiomyocytes, respectively. Intracellular Ca(2+) handing analysis revealed that increases in myofilament Ca(2+) responsiveness, together with increased rate of sarcoplasmic reticulum Ca(2+) reuptake, are associated with the enhanced contractility in PICOT-overexpressing cardiomyocytes. The inhibition of cardiac remodeling by of PICOT with a concomitant increase in ventricular function and cardiomyocyte contractility suggests that PICOT may provide an efficient modality for treatment of cardiac hypertrophy and heart failure.</P>

Modulation of Adherence, Invasion, and Tumor Necrosis Factor Alpha Secretion during the Early Stages of Infection by Streptococcus pneumoniae ClpL

Tu, Le Nhat,Jeong, Hye-Yoon,Kwon, Hyog-Young,Ogunniyi, Abiodun D.,Paton, James C.,Pyo, Suhk-Neung,Rhee, Dong-Kwon American Society for Microbiology 2007 Infection and immunity Vol.75 No.6

<B>ABSTRACT</B><P>Heat shock proteins (HSPs) play a pivotal role as chaperones in the folding of native and denatured proteins and can help pathogens penetrate host defenses. However, the underlying mechanism(s) of modulation of virulence by HSPs has not been fully determined. In this study, the role of the chaperone ClpL in the pathogenicity of <I>Streptococcus pneumoniae</I> was assessed. A <I>clpL</I> mutant adhered to and invaded nasopharyngeal or lung cells much more efficiently than the wild type adhered to and invaded these cells in vitro, as well as in vivo, although it produced the same amount of capsular polysaccharide. However, the level of secretion of tumor necrosis factor alpha (TNF-α) from macrophages infected with the <I>clpL</I> mutant was significantly lower than the level of secretion elicited by the wild type during the early stages of infection. Interestingly, treatment of the human lung epithelial carcinoma A549 and murine macrophage RAW 264.7 cell lines with cytochalasin D, an inhibitor of actin polymerization, increased adherence of the mutant to the host cells. In contrast, cytochalasin D treatment of RAW 264.7 cells decreased TNF-α secretion after infection with either the wild type or the mutant. However, pretreatment of cell lines with the actin polymerization activator jasplakinolide reversed these phenotypes. These findings indicate, for the first time, that the ClpL chaperone represses adherence of <I>S. pneumoniae</I> to host cells and induces secretion of TNF-α via a mechanism dependent upon actin polymerization during the initial infection stage.</P>

Kalopanaxsaponin A Exerts Anti-Inflammatory Effects in Lipopolysaccharide-Stimulated Microglia via Inhibition of JNK and NF-κB/AP-1 Pathways

( Yeon Hui Jeong ),( Jin Won Hyun ),( Tien Kim Van Le ),( Dong Hyun Kim ),( Hee Sun Kim ) 한국응용약물학회 2013 Biomolecules & Therapeutics(구 응용약물학회지) Vol.21 No.5

Microglial activation plays an important role in the development and progression of various neurological disorders such as cerebral ischemia, multiple sclerosis, and Alzheimer`s disease. Thus, controlling microglial activation can serve as a promising therapeutic strategy for such brain diseases. In the present study, we showed that kalopanaxsaponin A, a triterpenoid saponin isolated from Kalopanax pictus, inhibited inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and tumor necrosis factor (TNF)-α expression in lipopolysaccharide (LPS)-stimulated microglia, while kalopanaxsaponin A increased anti-infl ammatory cytokine interleukin (IL)-10 expression. Subsequent mechanistic studies revealed that kalopanaxsaponin A inhibited LPS-induced DNA binding activities of NF-κB and AP-1, and the phosphorylation of JNK without affecting other MAP kinases. Furthermore, kalopanaxsaponin A inhibited the intracellular ROS production with upregulation of anti-infl ammatory hemeoxygenase-1 (HO-1) expression. Based on the previous reports that JNK pathway is largely involved in iNOS and proinfl ammatory cytokine gene expression via modulating NF-κB/AP-1 and ROS, our data collectively suggest that inhibition of JNK pathway plays a key role in anti-infl ammatory effects of kalopanaxsaponin A in LPS-stimulated microglia.

HCV, Acute, LT : Model to Predict Recurrence after Living Donor Liver Transplantation for Hepatocellular Carcinoma beyond the Milan Criteria

( Yuri Cho ),( Jeong Hoon Lee ),( Dong Hyeon Lee ),( Min Jong Lee ),( Jeong Ju Yoo ),( Won Mook Choi ),( Young Youn Cho ),( Yun Bin Lee ),( Eun Ju Cho ),( Su Jong Yu ),( Nam Joon Yi ),( Kwang Woong Le 대한간학회 2013 춘·추계 학술대회 (KASL) Vol.2013 No.1

Background/aims: Some patients with hepatocellular carcinoma (HCC) beyond the Milan criteria (MC) have favorable tumor biology, and that these patients would have low risk of tumor recurrence after living donor liver transplantation (LDLT). This study was designed to develop a model of tumor recurrence after LDLT for HCC beyond the MC, so as to select the best candidates for LDLT in HCC beyond the MC. Methods: Consecutive patients who had undergone LDLT beyond the MC at Seoul National University Hospital between September 2001 and January 2013 were analyzed. Demographic, clinical, and tumor characteristics were evaluated and a model to predict recurrence after LDLT (MoRAL score) was created. Results: A total of 104 patients were included. The median follow-up was 52.7 (range, 1.6-157.5) months. Their 5-year overall survival and cumulative recurrence rates were 70.4% and 41.8%, respectively. In multivariate analysis, independent pretransplant risk factors for HCC recurrence were serum AFP (OR=1.003, P=0.013) and PIVKA-II (OR=1.001, P=0.050) levels. AFP reflected maximal tumor size and PIVKA-II reflected tumor number and type (nodular or diffuse/infiltrative) (all P<0.001). Using Cox proportional hazards model, MoRAL score ( )was derived (median, 108.3; range 33.7-3928.3). The concordance statistic of MoRAL (0.836) was superior to CLIP score (0.772), TNM stage (0.600), JIS stage (0.601) and T classification (0.626). The tumor recurrence after LDLT was significantly related to mortality (OR=21.6, P<0.001). Conclusions: A new model to predict tumor recurrence of HCC patients beyond the MC after LDLT based on objective parameters provides refined prognostication (Figure 1). External validation is warranted.

High-Performance Control of Three-Phase Four-Wire DVR Systems using Feedback Linearization

Seon-Yeong Jeong,Thanh Hai Nguyen,Quoc Anh Le,Dong-Choon Lee 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.1

Power quality is a critical issue in distribution systems, where a dynamic voltage restorer (DVR) is commonly used to mitigate the voltage disturbances for loads. This paper deals with a nonlinear control for the three-phase four-wire (3P-4W) DVR under a grid voltage unbalance and nonlinear loads in the distribution system, where a novel control scheme based on the feedback linearization technique is proposed. Through feedback linearization, a nonlinear model of a DVR with a PWM voltage-source inverter (VSI) and LC filters is linearized. Then, the controller design of the linearized model is performed by applying the linear control theory, where the load voltages are kept constant by controlling the d-q-0 axis components of the DVR output voltages. To keep the load voltage unchanged, an in-phase compensation strategy is employed, where the load voltages are recovered to be the same as the previous voltage without a change in the magnitude. With this strategy, the performance of the DVR becomes faster and more stable even under unbalanced source voltages and nonlinear loads. The validity of the proposed control strategy has been verified by simulation and experimental results.