Loop-Mediated Isothermal Amplification Assay Targeting the femA Gene for Rapid Detection of Staphylococcus aureus from Clinical and Food Samples

( Xi Hong Zhao ),( Yan Mei Li ),( Myoung Su Park ),( Jun Wang ),( You Hong Zhang ),( Xiao Wei He ),( Fereidoun ),( Forghani ),( Li Wang ),( Guang Chao Yu ),( Deog Hwan Oh ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.2

In this study, a loop-mediated isothermal amplification (LAMP) method to rapidly detect Staphylococcus aureus strains was developed and evaluated by extensively applying a large number of S. aureus isolates from clinical and food samples. Six primers were specially designed for recognizing eight distinct sequences on the species-specific femA gene of S. aureus. The detection limits were 100 fg DNA/tube and 104 CFU/ml. The LAMP assay was applied to 432 S. aureus strains isolated from 118 clinical and 314 food samples. Total detection rates for the LAMP and polymerase chain reaction assays were 98.4% (306/311) and 89.4% (278/311), respectively.

Review : Advances in Rapid Detection Methods for Foodborne Pathogens

( Xi Hong Zhao ),( Chii Wann Lin ),( Jun Wang ),( Deog Hwan Oh ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.3

Food safety is increasingly becoming an important public health issue, as foodborne diseases present a widespread and growing public health problem in both developed and developing countries. The rapid and precise monitoring and detection of foodborne pathogens are some of the most effective ways to control and prevent human foodborne infections. Traditional microbiological detection and identification methods for foodborne pathogens are well known to be time consuming and laborious as they are increasingly being perceived as insufficient to meet the demands of rapid food testing. Recently, various kinds of rapid detection, identification, and monitoring methods have been developed for foodborne pathogens, including nucleic-acid-based methods, immunological methods, and biosensor-based methods, etc. This article reviews the principles, characteristics, and applications of recent rapid detection methods for foodborne pathogens.

Effect of Circuit Parameters on Stability of Voltage-fed Buck-Boost Converter in Discontinuous Conduction Mode

Zhao-He Feng,Ren-Xi Gong,Qing-Yu Wang 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.4

The state transition matrix are obtained by solving state equations in terms of Laplace inverse transformation and Cayley-Hamilton theorem, and an establishment of a precise discreteiterative mapping of the voltage-fed buck-boost converter operating in discontinuous conduction mode is made. On the basis of the mapping, the converter bifurcation diagrams and Lyapunov exponent diagrams with the input voltage, the resistance, the inductance and the capacitance as the bifurcation parameters are obtained, and the effect of the parameters on the system stability is deeply studied. The results obtained show that they have a great influence on the stability of the system, and the general trend is that the increase of either the voltage-fed coefficient, input voltage or the load resistance, or the decrease of the filtering inductance, capacitance will make the system stability become poorer, and that all the parameters have a critical value, and when they are greater or less than the values, the system will go through stable 1T orbits, stable 2T orbits, 4T orbits, 8T orbits and eventually approaches chaos.

Experimental Study and Analysis of Insulator Breakdown Characteristics with Short-tail Lightning Impulse

Zhao, Yuan,Li, Yu,Deng, Chun,Yuan, Yi-Chao,He, Jin-Liang,Wang, Xi The Korean Institute of Electrical Engineers 2014 The Journal of International Council on Electrical Vol.4 No.3

The voltage waveform on the insulator by a direct lightning stroke is a short-tail lightning impulse. Experimental study and analysis of insulator breakdown characteristics under short-tail lightning impulses are given in this paper with the contrast of standard lightning impulse. The impacts of crossarm and transmission lines are also considered. The experimental results indicate that the insulator 50% breakdown voltage under short-tail impulse is significantly higher than that of standard wave with both positive and negative polarities, about 25~30%. The 50% breakdown voltage of insulator with negative-polarity short-tail impulse is about 5% higher than with positive-polarity one. The insulator voltage-time characteristics are also given with short-tail and standard lightning impulses.

Performance of the R-way Colposcopic Evaluation System in Cervical Cancer Screening

Zhao, Jian,Zhang, Xi,Chen, Rui,Zhao, Yu-Qian,Wang, Ting-Ting,He, Shan,Qiao, You-Lin Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.10

Objective: To investigate the diagnostic value of the R-way colposcopic evaluation system (R-way system) in cervical cancer screening. Materials and Methods: Between August 2013 and August 2014, a total of 1,059 cases referred to colposcopy in Peking University First Hospital were studied using both the R-way system and conventional colposcopy. Our study evaluated and compared the diagnostic ability of the two methods in detecting high-grade lesions and cervical cancer (hereinafter called CIN2+). Evaluation indicators including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), Youden index and the area under the curve (AUC) of the receiver operating characteristic (ROC) were calculated. Results: The R-way system had a slightly lower specificity (94.5%) than conventional colposcopy (96.0%) for CIN2+ detection (P=0.181). However, the sensitivity (77.8%) was significantly higher than with the conventional colposcopic method (46.6%) (${\chi}^2=64.351$, P<0.001). In addition, the AUC of the ROC for CIN2+ detection using the R-way system (0.839) was larger than that with conventional colposcopy (0.731) (Z=4.348, P<0.001). If preliminary result had been drawn from cervical exfoliated cytology before colposcopy referral, combination of the R-way system with cytology could increase the sensitivity to 93.9% for CIN2+ detection (excluding ASCUS\LSIL), confirmed by multipoint biopsy or ECC. Conclusions: The diagnostic value of the R-way evaluation system is higher than that of conventional colposcopic evaluation in cervical cancer screening. Moreover, taking the ease of use and standardized quality control management into account, the R-way system is highly preferable.

Genetic dissection of leaf-related traits using 156 chromosomal segment substitution lines

Xi Liu,Linglong Liu,Yinhui Xiao,Shijia Liu,Yunlu Tian,Liangming Chen,Zhiquan Wang,Ling Jiang,Zhigang Zhao,Jianmin Wan 한국식물학회 2015 Journal of Plant Biology Vol.58 No.6

A two-line super-hybrid rice (Oryza sativa L.) variety [Liangyoupei9 (LYP9)] demonstrated superiority over its both parents, viz. elite inbred lines 93-11 and Pei-ai64S (PA64S), as well as other conventional hybrids, and had long been exploited in China. However, the genetic basis of its leaf-related traits, supposed to be an important component for yield potential, remains elusive. Here, initially a set of chromosome segment substitution lines (CSSLs) was constructed, in which the genome of Pei-ai64S has been introgressed into the background of 93-11. This set was developed by marker aided selection, based on 123 polymorphic SSR markers. The introgressed chromosomal segments presented in the 156 CSSLs covered 96.46% of Pei-ai64S genome. Afterwards, the CSSLs were deployed to assess the genetic basis of leaf size (length and width) and chlorophyll content of top three leaves across five different environments. The CSSLs showed transgressive segregation for all of the traits, and significant correlations were detected among most of the traits. A total of 27 quantitative trait loci (QTL) were identified on ten chromosomes, and three QTL cluster affecting related traits were found on chromosome 3, 6, and 8, respectively. Remarkably, two key QTLs, qALW3-1 and qALW3-2, both controlling the antepenultimate leaf width, were identified in all five environments, and their effect were further validated by CSSLs harboring the two QTL alleles. Our results indicate that developing CSSLs is a powerful tool for genetic dissection of quantitative traits. Meanwhile, the QTLs controlling leaf-related traits uncovered here provide useful information for marker-assisted selection in improving the performance of leaf morphology and photosynthetic ability.

The Application of Cartilage Tissue Engineering with Cell-Laden Hydrogel in Plastic Surgery: A Systematic Review

Wang Guanhuier,Zhang Xinling,Bu Xi,An Yang,Bi Hongsen,Zhao Zhenmin 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.1

BACKGROUND: As a contour-supporting material, the cartilage has a significant application value in plastic surgery. Since the development of hydrogel scaffolds with sufficient biomechanical strength and high biocompatibility, cell-laden hydrogels have been widely studied for application in cartilage bioengineering. This systematic review summarizes the latest research on engineered cartilage constructed using cell-laden hydrogel scaffolds in plastic surgery. METHODS: A systematic review was performed by searching the PubMed and Web of Science databases using selected keywords and Medical Subject Headings search terms. RESULTS: Forty-two studies were identified based on the search criteria. After full-text screening for inclusion and exclusion criteria, 18 studies were included. Data collected from each study included culturing form, seed cell types and sources, concentration of cells and gels, scaffold materials and bio-printing structures, and biomechanical properties of cartilage constructs. These cell-laden hydrogel scaffolds were reported to show some feasibility of cartilage engineering, including better cell proliferation, enhanced deposition of glycosaminoglycans and collagen type II in the extracellular matrix, and better biomechanical properties close to the natural state. CONCLUSION: Cell-laden hydrogels have been widely used in cartilage bioengineering research. Through 3-dimensional (3D) printing, the cell-laden hydrogel can form a bionic contour structure. Extracellular matrix expression was observed in vivo and in vitro, and the elastic modulus was reported to be similar to that of natural cartilage. The future direction of cartilage tissue engineering in plastic surgery involves the use of novel hydrogel materials and more advanced 3D printing technology combined with biochemistry and biomechanical stimulation.

Arginine-Rich Manganese Silicate Nanobubbles as a Ferroptosis-Inducing Agent for Tumor-Targeted Theranostics

Wang, Shuaifei,Li, Fangyuan,Qiao, Ruirui,Hu, Xi,Liao, Hongwei,Chen, Lumin,Wu, Jiahe,Wu, Haibin,Zhao, Meng,Liu, Jianan,Chen, Rui,Ma, Xibo,Kim, Dokyoon,Sun, Jihong,Davis, Thomas P.,Chen, Chunying,Tian, American Chemical Society 2018 ACS NANO Vol.12 No.12

<P>Ferroptosis, an iron-based cell-death pathway, has recently attracted great attention owing to its effectiveness in killing cancer cells. Previous investigations focused on the development of iron-based nanomaterials to induce ferroptosis in cancer cells by the up-regulation of reactive oxygen species (ROS) generated by the well-known Fenton reaction. Herein, we report a ferroptosis-inducing agent based on arginine-rich manganese silicate nanobubbles (AMSNs) that possess highly efficient glutathione (GSH) depletion ability and thereby induce ferroptosis by the inactivation of glutathione-dependent peroxidases 4 (GPX4). The AMSNs were synthesized <I>via</I> a one-pot reaction with arginine (Arg) as the surface ligand for tumor homing. Subsequently, a significant tumor suppression effect can be achieved by GSH depletion-induced ferroptosis. Moreover, the degradation of AMSNs during the GSH depletion contributed to <I>T</I><SUB>1</SUB>-weighted magnetic resonance imaging (MRI) enhancement as well as on-demand chemotherapeutic drug release for synergistic cancer therapy. We anticipate that the GSH-depletion-induced ferroptosis strategy by using manganese-based nanomaterials would provide insights in designing nanomedicines for tumor-targeted theranostics.</P> [FIG OMISSION]</BR>

Identification of Petriella setifera LH and Characterization of Its Crude Carboxymethyl Cellulase for Application in Denim Biostoning

Xi-Hua Zhao,Wei Wang,Dong-Zhi Wei 한국미생물학회 2013 The journal of microbiology Vol.51 No.1

The phylogenetic tree of the partial elongation factor-1 alpha gene fits better than the partial 18S rDNA for generic classification. From the results of the molecular tree and analysis of morphological characters, Petriella setifera LH was identified. It can be induced to produce carboxymethyl cellulase (CMCase). The crude CMCase only shows a 44.1-kDa band by activity staining after SDS-PAGE. It is optimally active at 55°C and pH 6.0, and is stable from pH 5.0–8.0 and at 45°C or below. The crude CMCase, which is not affected by Co2+, is strongly activated in the presence of 10 mM Na+, K+, Ca2+, Mg2+, EDTA, and Mn2+. It is strongly inhibited by 10 mM Fe2+, Pb2+, Al3+, Zn2+, Ag+, Fe3+, and Cu2+. When compared with denim treatment by Novoprime A800 (a commercial neutral cellulase), crude CMCase exhibits a similar fabric weight loss and indigo dye removal. These results indicate that crude CMCase has potential application in denim biostoning.

Effects of Zinc on the Activity and Conformational Changes of Arginine Kinase and Its Intermediate

( Zhao Dong Du ),( Xi Cheng Wang ) 생화학분자생물학회 2003 BMB Reports Vol.36 No.4

The effects of zinc on arginine kinase and its collapsed-state intermediate were studied. Both arginine kinase and the collapsed-state intermediate were inactivated in the presence of zinc, following a biphasic kinetic course. The corresponding apparent rate constants of inactivation at different zinc concentrations and conformational changes in the presence of 0.5 mM zinc were obtained. The conformational changes of arginine kinase and the collapsed-state intermediate were followed by fluorescence spectra and circular dichroism spectra. Comparison of the results for arginine kinase and the collapsed-state intermediate showed that the collapsed-state intermediate was more susceptible to zinc, which indicated that the collapsed-state intermediate was more flexible and unstable than arginine kinase. The special structure of arginine kinase might explain these diverse phenomena.