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Synthesis of Ni/Fe Nanoparticles Utilizing PVP–SDS Bound Micelles as a Template to Remove PCB77
Shu Ding,Lin Zhao,Yun Qi,Qianqian Lv 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.3
In the present study, Ni/Fe nanoparticles were synthesized using bound micelles as a template and 3, 3', 4, 4'-tetrachlorobiphenyl (PCB77) as the target contaminant. The dual bound micelles, which are composed of polyvinylpyrrolidone (PVP) and sodium dodecyl sulfate (SDS), were found to be superior to single-component templates for the dispersion of metallic ions and thus directed the synthesis of Ni/Fe nanoparticles with improved properties. After characterization of the different nanoparticles, it was found that the sustained effectiveness of PVP–SDS bound micelles afforded specialized structures with two gradations of Ni/Fe nanoparticles, correlating to more active sites and higher activity. The improved activity of the Ni/Fe nanoparticles was finally exhibited by the higher ratio (99.3% in 72 h) and efficiency (kobs of 0.0674 h-1) of PCB77 removal. Herein, the utilization of PVP–SDS bound micelles is proposed as a template for the improvement of iron-based nanoparticles and correlated research.
( Ding Xin Wu ),( Lin Chun Wang ),( Yuwei Li ),( Shu Miao Zhao ),( Nan Peng ),( Yun Xiang Liang ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.2
An exo-β-D-glucosaminidase (AorCsxA) from Aspergillus oryzae FL402 was heterologously expressed and purified. The deduced amino acid sequence indicated that AorCsxA belonged to glycoside hydrolase family 2. AorCsxA digested colloid chitosan into glucosamine but not into chitosan oligosaccharides, demonstrating exo-β-D-glucosaminidase (CsxA) activity. AorCsxA exhibited optimal activity at pH 5.5 and 50°C; however, the enzyme expressed Pichia pastoris (PpAorCsxA) showed much stronger thermostability at 50°C than that expressed in Escherichia coli (EcAorCsxA), which may be related to glycosylation. AorCsxA activity was inhibited by EDTA and most of the tested metal ions. A single amino acid mutation (F769W) AorCsxA significantly enhanced the specific activity and hydrolysis velocity as revealed comparison of V_{max} and k_{cat} values with those of the wild-type enzyme. The three-dimensional structure suggested the tightened pocket at the active site of F769W enabled efficient substrate binding. The AorCsxA gene was heterologously expressed in P. pastoris, and one transformant was found to produce 222 U/ml activity during the high-cell-density fermentation. This AorCsxA-overexpressing P. pastoris strain is feasible for large-scale production of AorCsxA.
He, Ying-Xia,Ye, Cheng-Lin,Zhang, Pei,Li, Qiao,Park, Chae Gyu,Yang, Kun,Jiang, Ling-Yu,Lv, Yin,Ying, Xiao-Ling,Ding, Hong-Hui,Huang, Hong-Ping,Mambwe Tembo, John,Li, An-Yi,Cheng, Bing,Zhang, Shu-Sheng American Society for Microbiology 2019 Infection and immunity Vol.87 No.1
<P><I>Yersinia pseudotuberculosis</I> is a Gram-negative enteropathogen and causes gastrointestinal infections. It disseminates from gut to mesenteric lymph nodes (MLNs), spleen, and liver of infected humans and animals.</P><P><I>Yersinia pseudotuberculosis</I> is a Gram-negative enteropathogen and causes gastrointestinal infections. It disseminates from gut to mesenteric lymph nodes (MLNs), spleen, and liver of infected humans and animals. Although the molecular mechanisms for dissemination and infection are unclear, many Gram-negative enteropathogens presumably invade the small intestine via Peyer’s patches to initiate dissemination. In this study, we demonstrate that <I>Y. pseudotuberculosis</I> utilizes its lipopolysaccharide (LPS) core to interact with CD209 receptors, leading to invasion of human dendritic cells (DCs) and murine macrophages. These <I>Y. pseudotuberculosis</I>-CD209 interactions result in bacterial dissemination to MLNs, spleens, and livers of both wild-type and Peyer’s patch-deficient mice. The blocking of the <I>Y. pseudotuberculosis</I>-CD209 interactions by expression of O-antigen and with oligosaccharides reduces infectivity. Based on the well-documented studies in which HIV-CD209 interaction leads to viral dissemination, we therefore propose an infection route for <I>Y. pseudotuberculosis</I> where this pathogen, after penetrating the intestinal mucosal membrane, hijacks the <I>Y. pseudotuberculosis</I>-CD209 interaction antigen-presenting cells to reach their target destinations, MLNs, spleens, and livers.</P>
( Wen Fei Xue ),( Jing Fu Peng ),( Xiao Li Yu ),( Shu Lin Zhang ),( Boping Zhou ),( Dan Qing Jiang ),( Jian Bo Chen ),( Bing Bing Ding ),( Bin Zhu ),( Yao Li ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.1
The widespread occurrence of drug-resistant Mycobacterium tuberculosis places importance on the detection of TB (tuberculosis) drug susceptibility. Conventional drug susceptibility testing (DST) is a lengthy process. We developed a rapid enzymatic color-reaction-based biochip assay. The process included asymmetric multiplex PCR/templex PCR, biochip hybridization, and an enzymatic color reaction, with specific software for data operating. Templex PCR (tem- PCR) was applied to avoid interference between different primers in conventional multiplex- PCR. We applied this assay to 276 clinical specimens (including 27 sputum, 4 alveolar lavage fluid, 2 pleural effusion, and 243 culture isolate specimens; 40 of the 276 were non-tuberculosis mycobacteria specimens and 236 were M. tuberculosis specimens). The testing process took 4.5 h. A sensitivity of 50 copies per PCR was achieved, while the sensitivity was 500 copies per PCR when tem-PCR was used. Allele sequences could be detected in mixed samples at aproportion of 10%. Detection results showed a concordance rate of 97.46% (230/236) in rifampicin resistance detection (sensitivity 95.40%, specificity 98.66%) and 96.19% (227/236) in isoniazid (sensitivity 93.59%, specificity 97.47%) detection with those of DST assay. Concordance rates of testing results for sputum, alveolar lavage fluid, and pleural effusion specimens were 100%. The assay provides a potential choice for TB diagnosis and treatment.
THE MAGNETIC SEPARATION OF Nd - Fe - B POWDERS
Li-Ya Cui,Da-Li Zheng,Jing-Han Zhu,Wei-Hong Zhao,Shu-Lin Ding 한국자기학회 1995 韓國磁氣學會誌 Vol.5 No.5
The magnetic separation of Nd-Fe-B powders prepared by melt-spun and HDDR processes was investigated. The experiments show that the ununiform melt-spun powders can be separated into various standards by means of magnetic separation method. The magnetic powders with higher properties were obtained by the use of suitable separating field. For example, the properties of ununiform melt-spun powders are Br=7.95 kG, iHc=9.93 kOe and (BH)max=10.2 MGOe before separating. Through separating in different magnetic fields, the powders obtained with a separating field of 780 Oe has the optimum properties of Br=7.7 kG, iHc=11.0 kOe and (BH)max=15.3 MGOe. The magnetic properties of the HDDR magnetic powder are hardly separated by the magnetic separation method.
Rhodococcus soli sp. nov., an actinobacterium isolated from soil using a resuscitative technique.
Li, Shan-Hui,Yu, Xiao-Yun,Park, Dong-Jin,Hozzein, Wael N,Kim, Chang-Jin,Shu, Wen-Sheng,Wadaan, Mohammed A M,Ding, Lin-Xian,Li, Wen-Jun N.V. Swets en Zeitlinger 2015 Antonie van Leeuwenhoek Vol.107 No.2
<P>A Gram-positive, aerobic, non-motile, non-spore forming strain, designated DSD51W(T), was isolated using a resuscitative technique from a soil sample collected from Kyoto park, Japan, and characterized by using a polyphasic approach. The morphological and chemotaxonomic properties of the isolate were typical of those of members of the genus Rhodococcus. Strain DSD51W(T) was found to form a coherent cluster with Rhodococcus hoagii ATCC 7005(T), Rhodococcus equi NBRC 101255(T), Rhodococcus defluvii Call(T) and Rhodococcus kunmingensis YIM 45607(T) as its closest phylogenetic neighbours in 16S rRNA gene sequence analysis. However, the DNA-DNA hybridization values with the above strains were 58.2 ± 2.2, 58.4 ± 1.9, 45.1 ± 1.4 and 40.3 ± 4.7 %, respectively. In combination with differences in physiological and biochemical properties, strain DSD51W(T) can be concluded to represent a novel species of the genus Rhodococcus, for which the name Rhodococcus soli sp. nov. is proposed, with the type strain DSD51W(T) (=KCTC 29259(T) = JCM 19627(T) = DSM 46662(T) = KACC 17838(T)).</P>
Zu-Guo Zhao,Yun Mei Yu,Bi Yu Xu,Shuang-Shuang Yan,Jun-Fa Xu,Fang Liu,Guo-Ming Li,Yuan Lin Ding,Shu Qing Wu 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.2
In Pseudomonas aeruginosa, a quorum sensing (QS) system regulates the expression of many virulence factors. N-acyl homoserine lactone (HSL) is the signal molecule of QS system. In order to find a novel HSL binder to interfere with QS signaling and to attenuate P. aeruginosa virulence, an amino lactam surrogate (ALS) of HSL was used as a target to screen HSL aptamers with the technique of systematic evolution of ligands by exponential enrichment (SELEX). Eight HSL aptamers with high affinities for 3O-C12-HSL (20 nM ≤ Kd < 35 nM) or C4-HSL (25 nM < Kd < 50 nM) were finally obtained. In vitro QS-inhibiting study of P. aeruginosa showed that HSL aptamers could inhibit virulence in a dose-dependent manner. ALSap-8 which bound C4-HSL primarily acted on the rhl system and inhibited the secretion of pyocyanin. ALSap-5 which bound 3O-C12-HSL not only showed strong inhibitory activity on biofilm formation as well as secretions of LasA protease and LasB elastase, but also reduced pyocyanin secretion. Since the las system is capable of activating the rhl system mildly, we speculated that ALSap-5 can simultaneously interfere with the las and rhl systems. High-affinity aptamers against HSL in this study are novel QS and virulence-inhibitors, and may have potential as drug candidates for the treatment of P. aeruginosa infection.