Browsing by Author "Peng, H. L."

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Genetically closely related azole-resistant Candida tropicalis in environments can be a threat to healthcare
(2018-06-01)
Zhou, Z. L.
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Tsai, J. N.
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Tseng, M. N.
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Liu, H. L.
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Lin, C. C.
RmpA Regulation of Capsular Polysaccharide Biosynthesis in Klebsiella pneumoniae CG43
(2010-06-01)
Cheng, H. Y.
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Chen, Y. S.
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Wu, C. Y.
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Chang, H. Y.
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Lai, Y. C.
Sequence analysis of the large virulence plasmid pLVPK in Klebsiella pneumoniae CG43 revealed the presence of another mucoid factor encoding gene rmpA besides rmpA2. Promoter activity measurement indicated that the deletion of rmpA reduced K2 capsular polysaccharide (CPS) biosynthesis, resulting in decreased colony mucoidy and virulence in mice. Introduction of a multicopy plasmid carrying rmpA restored CPS production in the rmpA or rmpA2 mutant but not in the rcsB mutant. Transformation of the rmpA deletion mutant with an rcsB-carrying plasmid also failed to enhance CPS production, suggesting that a cooperation of RmpA with RcsB is required for regulatory activity. This was further corroborated by the demonstration of in vivo interaction between RmpA and RcsB using two-hybrid analysis and coimmunoprecipitation analysis. A putative Fur binding box was only found at the 5' noncoding region of rmpA. The promoter activity analysis indicated that the deletion of fur increased the rmpA promoter activity. Using electrophoretic mobility shift assay, we further demonstrated that Fur exerts its regulatory activity by binding directly to the promoter. As a result, the fur deletion mutant exhibited an increase in colony mucoidy, CPS production, and virulence in mice. In summary, our results suggested that RmpA activates CPS biosynthesis in K. pneumoniae CG43 via an RcsB-dependent manner. The expression of rmpA is regulated by the availability of iron and is negatively controlled by Fur.
The improvement of catalytic efficiency by optimizing Pt on carbon cloth as a cathode of a microbial fuel cell
(2013-10-01)
Yen, S. J.
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Tsai, M. C.
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Wang, Z. C.
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Peng, H. L.
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Tsai, C. H.
This paper presents the performance of Pt deposited by different deposition methods, including electrodeposition, e-gun, and sputtering on a carbon cloth as a cathode in a microbial fuel cell (MFC) system. The results indicate that Pt deposited by electrodeposition exhibits the highest active efficiency on hydrogen electroabsorption. According to XPS fitting results, the amount of Pt (0), zero-valent Pt, existing in Pt deposited on carbon cloth by electrodeposition was larger than that in Pt deposited by e-gun and sputtering. The cyclic voltammogram analyses also show more real active surface area of Pt deposited by electrodeposition, mostly contributed by its smaller particle size/shape and higher catalytic effect. Besides, the total impedance of Pt deposited by electrodeposition was lower than that of Pt deposited by e-gun and sputtering from EIS measurement at 0.1 Hz. Applied to MFC system, the highest power density was manifested and the least Pt loading were observed for the Pt deposited on carbon cloth by electrodeposition. It is therefore can be concluded that the electrodeposited-Pt exhibit superior performance as a cathode for future MFC applications. (C) 2013 Elsevier Ltd. All rights reserved.