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1
Glycoepitopes of Staphylococcal Wall Teichoic Acid Govern Complement-mediated Opsonophagocytosis via Human Serum Antibody and Mannose-binding Lectin

Kurokawa, Kenji,Jung, Dong-Jun,An, Jang-Hyun,Fuchs, Katharina,Jeon, Yu-Jin,Kim, Na-Hyang,Li, Xuehua,Tateishi, Koichiro,Park, Ji Ae,Xia, Guoqing,Matsushita, Misao,Takahashi, Kazue,Park, Hee-Ju,Peschel, American Society for Biochemistry and Molecular Bi 2013 The Journal of biological chemistry Vol.288 No.43
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Serum antibodies and mannose-binding lectin (MBL) are important host defense factors for host adaptive and innate immunity, respectively. Antibodies and MBL also initiate the classical and lectin complement pathways, respectively, leading to opsonophagocytosis. We have shown previously that Staphylococcus aureus wall teichoic acid (WTA), a cell wall glycopolymer consisting of ribitol phosphate substituted with α- or β-O-N-acetyl-d-glucosamine (GlcNAc) and d-alanine, is recognized by MBL and serum anti-WTA IgG. However, the exact antigenic determinants to which anti-WTA antibodies or MBL bind have not been determined. To answer this question, several S. aureus mutants, such as α-GlcNAc glycosyltransferase-deficient S. aureus ΔtarM, β-GlcNAc glycosyltransferase-deficient ΔtarS, and ΔtarMS double mutant cells, were prepared from a laboratory and a community-associated methicillin-resistant S. aureus strain. Here, we describe the unexpected finding that β-GlcNAc WTA-deficient ΔtarS mutant cells (which have intact α-GlcNAc) escape from anti-WTA antibody-mediated opsonophagocytosis, whereas α-GlcNAc WTA-deficient ΔtarM mutant cells (which have intact β-GlcNAc) are efficiently engulfed by human leukocytes via anti-WTA IgG. Likewise, MBL binding in S. aureus cells was lost in the ΔtarMS double mutant but not in either single mutant. When we determined the serum concentrations of the anti-α- or anti-β-GlcNAc-specific WTA IgGs, anti-β-GlcNAc WTA-IgG was dominant in pooled human IgG fractions and in the intact sera of healthy adults and infants. These data demonstrate the importance of the WTA sugar conformation for human innate and adaptive immunity against S. aureus infection.
2
The Influence of a Second Metal on the Ni/SiC Catalyst for the Methanation of Syngas

( Lan Lan Song ),( Yue Yu ),( Xiao Xiao Wang ),( Guoq Jang Jin ),( Ying Yong Wang ),( Xiang Yun Guo ) 한국화학공학회 2014 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.52 No.5
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The catalytic performance of silicon carbide supported nickel catalysts modified with or without secondmetal (Co, Cu and Zn) for the methanation of CO has been investigated in a fixed-bed reactor using a feed consisting of25% CO and 75% H2 without any diluent gas. It has been found that the introduction of Co species can clearly improvethe catalytic activity of Ni/SiC catalyst, whereas the addition of Cu or Zn can result in a significant decrease in the catalyticactivity. The characterizations by means of XRD, TEM, XPS, CO-TPD and H2-TPR indicate that the addition ofCo could decrease the particle size of active metal, increase active sites on the surface of methanation catalyst, improvethe chemisorption of CO and enhance the reducibility of methanation catalysts. Additionally, the special interaction betweenCo species and Ni species is likely favorable for the dissociation of adsorbed CO on the surface of catalyst, and this mayalso contribute to the high activity of 5Co-Ni/SiC catalyst for CO methanation reaction. For 5Cu-Ni/SiC catalyst and 5Zn-Ni/SiC catalyst, Cu and Zn species could cover partial nickel particles and decrease the chemisorption amount of CO. These could be responsible for the low methanation activity. In addition, a 150h stability test under 2 MPa and 300 oCshowed that 5Co-Ni/SiC catalyst was very stable for CO methanation reaction.