http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
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>
Deep Regression for Precise Geometric Dimension Measurement
Thang Duong Nhat,Binh Nguyen Duc,Phuong Le Khac,Ngoc Tu Nguyen,Mai Nguyen Thi Phuong 한국정밀공학회 2019 한국정밀공학회지 Vol.36 No.8
A planar-dimensions vision measurement method is proposed by developing a Neural Network to measure real-world distance between any two points on the plane. The system leveraging Neural Network ability to search in the solution space is a highly non-linear model that could map points’ location on the pixel plane of image(s) with the actual distance between them considering the non-uniform geometric distortion in captured images caused by the entocentric lens in a common camera. The method was tested with a printed calibration chessboard, placed in different locations on the plane, with measured distance between tested points. Experimental results show the proposed method’s mean absolute error is 1.24 × 10-2 mm and standard deviation is 1.63 × 10-3 mm, tested with 10-folds cross-validation method.
Nguyen, Cuong Thach,Le, Nhat-Tu,Tran, Thao Dang-Hien,Kim, Eun-Hye,Park, Sang-Sang,Luong, Truc Thanh,Chung, Kyung-Tae,Pyo, Suhkneung,Rhee, Dong-Kwon American Society for Microbiology 2014 Infection and immunity Vol.82 No.9
<P>Caseinolytic protease L (ClpL) is a member of the HSP100/Clp chaperone family, which is found mainly in Gram-positive bacteria. ClpL is highly expressed during infection for refolding of stress-induced denatured proteins, some of which are important for adherence. However, the role of ClpL in modulating pneumococcal virulence is poorly understood. Here, we show that ClpL impairs pneumococcal adherence to A549 lung cells by inducing and activating Rap1 and Rac1, thus increasing phosphorylation of cofilin (inactive form). Moreover, infection with a <I>clpL</I> mutant (Δ<I>clpL</I>) causes a greater degree of filopodium formation than D39 wild-type (WT) infection. Inhibition of Rap1 and Rac1 impairs filopodium formation and pneumococcal adherence. Therefore, ClpL can reduce pneumococcal adherence to A549 cells, likely via modulation of Rap1- and Rac1-mediated filopodium formation. These results demonstrate a potential role for ClpL in pneumococcal resistance to host cell adherence during infection. This study provides insight into further understanding the interactions between hosts and pathogens.</P>
Role for SUMOylation in Disturbed Flow-induced Atherosclerotic Plaque Formation
Jun-ichi Abe,Nhat-Tu Le,허경선 대한의용생체공학회 2015 Biomedical Engineering Letters (BMEL) Vol.5 No.3
Although atherosclerosis is a multi-factorial disease, thefocalization of atherosclerotic plaques on the vessel wallsuggests that local factors such as patterns of local bloodflow are critical in the progression of atherosclerosis. Bloodflow creates various types of forces onto the surface ofvascular endothelial cells (ECs). Among those various typesof forces, fluid shear stress has a major influence on thestructure and function of ECs. At the branch points and thelesser curvature of the aortic arch, blood flow is disturbed (dflow)and atherosclerotic plaques are frequently detected. Atthe straight parts of the arterial tree and the greater curvatureof aortic arch, blood flow is steady (s-flow, high shear stress)and atherosclerotic plaques are rare. These two patterns ofblood flow (d-flow and s-flow) affects EC structure andfunction differently. However, molecular mechanisms underlinethe difference remains unclear. To provide insights into thisquestion, studies have suggested a number of theories withmultiple proposed signaling pathways, and the role ofpost-translational modifications has emerged. Particularly,SUMOylation is highlighted based on its potentiality toregulate a wide range of cellular functions. EC dysfunctioninduced by SUMOylation is proposed to accelerate d-flowinducedatherosclerosis. In this review, we focus onSUMOylation and its role in regulating transcriptional networksand propose a mechanistic link between d-flow and ECdysfunction. Since a strong correlation exists between d-flowand atherosclerotic plaque formation, understanding themechanism of d-flow-induced SUMOylation events mayreveal new paths towards therapeutic interventions againstEC dysfunction and atherosclerosis.
Yun Mi Lee,Jae Kap Jeong,Jung Mi Lee,Eun-Hye Kim,Tu Nhat Le,Dong-Kwon Rhee,Hyun-Ah Kang,Doo-Byoung Oh,Ohsuk Kwon 한국당과학회 2009 한국당과학회 학술대회 Vol.2009 No.1
Streptococcus pneumoniae, the major causative agent for pneumonia, otitis media and meningitis, produces surface exoglycosidases such as neuraminidase (NanA), β-galactosidase (BgaA) and N-acetylglucosaminidase (StrH). These enzymes play critical roles for colonization and pathogenesis by sequentially hydrolyzing various glycoconjugates to penetrate host defense molecules, to expose binding sites on the surface of the epithelial cells or to obtain monosaccharides for growth. In this study, we characterized a novel β-galactosidase encoded by the bgaC gene of S. pneumoniae. The recombinant BgaC protein exhibited a highly regio- and sugar-specific hydrolysis activity for Galβ(1,3)GlcNAc moiety of oligosaccharides. Interestingly, the BgaC was shown to be expressed as a surface protein, even though it does not have a typical signal sequence or membrane anchorage motif. The bgaC mutant strains did not show detectable changes in growth or morphology compared to wild type stains when cultivated under normal laboratory conditions. However, the bgaC mutant showed higher colonization levels at 6 and 12 h post-infection in vivo than the wild type. Our data strongly indicate that S. pneumoniae BgaC is a surface-associated β-galactosidase with a specific hydrolysis activity that contributes significantly to the adherence and invasion of pneumococci in vivo and in vitro.
Customer Satisfaction with Less than Container Load Cargo Services in HoChiMinh City, Vietnam
GIAO, Ha Nam Khanh,THY, Nguyen Thi Anh,VUONG, Bui Nhat,TU, Tran Ngoc,VINH, Pham Quang,LIEN, Le Thi Phuong Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.8
This research has four specific objectives: (1) identifying factors that affect customer satisfaction with less than container load (LCL) cargo services of logistics companies in HoChiMinh City (HCMC), (2) measuring the level of impact of the factors, (3) testing the difference in satisfaction among groups of customers with different characteristics in terms of type of business and time of using LCL cargo services, and (4) proposing some management implications to improve the quality of LCL cargo services. Researchers interviewed 210 customers who enjoyed the LCL cargo service in HCMC for at least the last six months, using the convenient sampling method. SPSS 20 was used to analyze the reliability of the scale through the Cronbach's alpha coefficient, then exploratory factor analysis and multiple linear regression analysis were used. The results identified the six factors that influence positively customer satisfaction of LCL cargo services of logistics companies in HCMC, by decreasing importance: service process, image, resource, price, management, and outcomes. The results show that there is no difference in customer satisfaction with LCL cargo services by types of business as well as time of using services. The research suggests some implications for the management of logistics companies in HCMC to enhance customer satisfaction.
Yun Mi Lee,Jae Kap Jeong,Ohsuk Kwon,Doo-Byoung Oh,Jung Mi Lee,Seonghun Kim,Eun-Hye Kim,Tu Nhat Le,Dong-Kwon Rhee,Hyun-Ah Kang 한국당과학회 2008 한국당과학회 학술대회 Vol.2008 No.1
Streptococcus pneumoniae is a causative agent for high morbidity and mortality. Although sugar moieties have been recognized as a ligand for initial contact with the host, only a few exoglycosidaseshave been reported in S. pneumoniae. In this study, a putative -galactosidase, encoded by the bgaC gene of S. pneumoniae, was characterized for its enzymatic activity and virulence. The recombinant BgaC protein, expressed and purified from Escherichia coli, was found to have a highly regiospecific and sugar specific hydrolysis activity for the Gal1-3-GlcNAc moiety of oligosaccharide. Interestingly, the BgaC hydrolysis activity was localized at the cell surface of S. pneumoniae, indicating that BgaC is expressed as a surface protein although it does not have a typical signal sequenceor membrane anchorage motif. The surface localization of BgaC was further supported by immunofluorescence microscopy analysis using an antibody raised against BgaC. Although the bgaC deletion mutation did not significantly attenuate the virulence of S. pneumoniae in vivo, the bgaC mutant strain showed relatively lower viable cell numbers compared to the wild type after 24 h infection in vivo, whereas it showed higher adherence and invasion at 6 and 12 h post- infection in vivo. Our data strongly indicate for the first time that S. pneumoniae bgaC encodes a surface β-galactosidase with high substrate specificity that is significantly associated with the infection activity of pneumococci.
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>