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Xuelian Li,
Wei Liu,
Jie Wang, Dayang Zou,
Xuesong Wang,
Zhan Yang,
Zhitao Yin,
Qian Cui,
Wei Shang,
Huan Li,
Xiao Wei,
Jing Cui,
Zhongquan Wang,
Liuyu Huang,
Jing Yuan
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ABSTRACT: Trichinellaspiralisis a tissue-dwelling nematode parasite. A loop-mediated isothermal amplification (LAMP) assay was developed and validated for the sensitive and rapid detection of T. spiralis larvae in muscle samples. Sixteen sets of primers were designed to recognize distinct sequences of a conserved gene, a 1.6kb repetitive element of the Trichinella genome. One set of primers was selected as the most appropriate for rapid detection. The specificity and sensitivity of the primers in LAMP reactions for T. spiralis larvae and muscle samples of mice infected with T. spiraliswere determined. Another 10 heterologous parasites were selected for specificity assays. The results showed that target DNA was amplified and visualized by monitoring turbidity and adding calcein detection methods within 70 min at an isothermal temperature of 63°C. The sensitivity of LAMP with the detection limit of 362 fg/μl was >10 times higher than that for PCR. The designed primers had a good specificity. No cross-reactivity was found with the DNA of any other parasites. The assay was able to detect T. spiralis in all mouse muscle samples infected with 10 T. spiralis larvae on day 20 p.i. We believe this is the first report regarding the application of the LAMP assay for detection of T. spiralis larvae in muscle samples from experimentally infected mice. This method demonstrates a potentially valuable means for the direct detection of T. spiralis larvae in meat inspection.
International journal for parasitology 11/2012; · 3.39 Impact Factor
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Xuesong Wang,
Wei Liu, Dayang Zou,
Xuelian Li,
Xiao Wei,
Wei Shang,
Yufei Wang,
Huan Li,
Yufei Wang Huan Li,
Xiang He,
Liuyu Huang,
Jing Yuan
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ABSTRACT: New Delhi Metallo-β-Lactamase 1 (NDM-1) is spreading worldwide and represents a major threat to health. To investigate the infection status and the species distribution of NDM-1-producing bacteria in China, a total of 10273 clinical fresh faecal samples of separate individuals were collected and analysed. Our results showed that the total infection rates of NDM-1-producing intestinal bacteria in clinical patients were 14.8%.
Clinical Infectious Diseases 09/2012; · 9.15 Impact Factor
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Changlin Shao,
Wei Shang,
Zhan Yang,
Zhongke Sun,
Yunmei Li,
Jing Guo,
Xuesong Wang, Dayang Zou,
Simiao Wang,
Hong Lei, [......],
Xuelian Li,
Xiao Wei,
Wei Liu,
Xiang He,
Zheng Jiang,
Shuangkui Du,
Xiangru Liao,
Liuyu Huang,
Yufei Wang,
Jing Yuan
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ABSTRACT: Bacteria utilize a quorum sensing (QS) system to coordinate gene expression by monitoring the concentration of molecules known as autoinducers (AI). In the present study, we confirmed the presence of a LuxS/AI-2 dependent QS system in vancomycin-resistant Enterococcus faecalis V583. Then, the cellular targets controlled by AI-2 were identified by comparative proteomics analysis in order to elucidate the possible role of AI-2 in E. faecalis. Results demonstrated 15 proteins that are differentially expressed upon the addition of AI-2, including proteins involved in metabolism, translation, energy production and/or conversion, and cell wall biogenesis. Glyceraldehyde-3-phosphate dehydrogenase and malate dehydrogenase associated with carbohydrate metabolism and energy production were up-regulated upon inducing by AI-2. In addition, externally added AI-2 could down-regulate acetyl-coenzyme A carboxylase and ornithine carbamoyltransferase, two key enzyme involved in metabolism. All these data suggest that AI-2 signaling may play a role in the regulation of a number of important metabolic properties of E. faecali. We further investigated the role of AI-2 in biofilm formation by E. faecalis, showing the addition of AI-2 to E. faecalis V583 cultures resulted in increased biofilm formation. Our results provide important clues to the role of a LuxS/AI-2 dependent QS system in vancomycin-resistant E. faecalis.
Journal of Proteome Research 08/2012; 11(9):4465-75. · 5.11 Impact Factor
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Wei Liu, Dayang Zou,
Xuesong Wang,
XueLian Li,
Li Zhu,
Zhitao Yin,
Zhan Yang,
Xiao Wei,
Li Han,
Yufei Wang,
Changlin Shao,
Simiao Wang,
Xiang He,
Dawei Liu,
Feng Liu,
Jie Wang,
Liuyu Huang,
Jing Yuan
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ABSTRACT: The co-occurrence of L1 and AmpR-L2 with bla(NDM-1) gene with an upstream 250-bp promoter was detected in a clinical isolate of Stenotrophomonas maltophilia DCPS-01, which was resistant to all β-lactams and sensitive only to colistin and fluoroquinolones. To investigate expression of resistance genes and the molecular mechanisms of bacteria resistance to carbapenems, proteomic profiles of the isolate was passaged with and without the drug by using 2D-PAGE. The results showed that 33 genes exhibiting a ≥3-fold change were identified as candidates that may help S. maltophilia survive drug selection. Strikingly, L1 was expressed more highly in cells grown with imipenem, and the abundant NDM-1 further increased, while very little L2 was detected even following induction. Specific activities for β-lactamase revealed that L2 remained at constitutive low levels (10.6 U/mg), while L1 and NDM-1 showed clear activity (69.8 U/mg). Our data support that imipenem could specifically and reversibly induce L1 and NDM-1, which together played key roles in drug resistance in DCPS-01. Although NDM-1 mediated resistance to carbapenems has been found in very few cases, to our knowledge, this is the first proteomics research of S. maltophilia with NDM-1, giving very broad-spectrum antibiotic resistance profiles.
Journal of Proteome Research 06/2012; 11(8):4024-33. · 5.11 Impact Factor
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Wei Liu, Dayang Zou,
Yan Li,
Xuesong Wang,
Xiang He,
Xiao Wei,
Changlin Shao,
Xuelian Li,
Wei Shang,
Kaitao Yu,
Dawei Liu,
Yunmei Li,
Jing Guo,
Zhitao Yin,
Jing Yuan
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ABSTRACT: New Delhi metallo-β-lactamase 1 (NDM-1), which is associated with resistance to carbapenem, was first reported in 2008. A sensitive and rapid molecular assay to detect the plasmid bla(NDM-1) in clinical isolates is needed to control its spread. We describe a loop-mediated isothermal amplification (LAMP) assay for the rapid detection of bla(NDM-1) from pure culture and sputum, urine, and fecal samples. Eight sets of primers were designed to recognize six or eight distinct sequences on target bla(NDM-1), and one set was selected as the most appropriate set of primers for its rapid detection. The specificity and sensitivity of the primers in the LAMP reactions for bla(NDM-1) detection were determined. The sensitivity of the LAMP assay for bla(NDM-1) detection in sputum, urine, and fecal samples was also tested. Two methods, namely, monitoring of turbidity and addition of calcein to the reaction tube, were used to determine negative and positive results. The results showed that target DNA was amplified and visualized by the two detection methods within 70 min at an isothermal temperature of 65°C. The sensitivity of LAMP, with a detection limit of 10.70 pg/μl DNA, was 100-fold greater than that of PCR. Thirteen infection bacterial strains without bla(NDM-1) were selected for testing of specificity, and the results of the amplification were negative, which showed that the primers had good levels of specificity. The LAMP method reported here is demonstrated to be a potentially valuable means for the detection of bla(NDM-1) and rapid clinical diagnosis, being fast, simple, and low in cost.
Journal of clinical microbiology 02/2012; 50(5):1580-5. · 4.16 Impact Factor
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Xiao Wei,
Yanhong Guo,
Changlin Shao,
Zhongke Sun,
Daria Zhurina,
Dawei Liu,
Wei Liu, Dayang Zou,
Zheng Jiang,
Xuesong Wang,
Jiangli Zhao,
Wei Shang,
Xuelian Li,
Xiangru Liao,
Liuyu Huang,
Christian U Riedel,
Jing Yuan
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ABSTRACT: Recently, a putative ATP-binding cassette (ABC) transport system was identified in Bifidobacterium longum NCC2705 that is highly up-regulated during growth on fructose as the sole carbon source. Cloning and expression of the corresponding ORFs (bl0033-0036) result in efficient fructose uptake by bacteria. Sequence analysis reveals high similarity to typical ABC transport systems and suggests that these genes are organized as an operon. Expression of FruE is induced by fructose, ribose, or xylose and is able to bind these sugars with fructose as the preferred substrate. Our data suggest that BL0033-0036 constitute a high affinity fructose-specific ABC transporter of B. longum NCC2705. We thus suggest to rename the coding genes to fruEKFG and the corresponding proteins to FruE (sugar-binding protein), FruK (ATPase subunit), FruF, and FruG (membrane permeases). Furthermore, protein-protein interactions between the components of the transporter complex were determined by GST pulldown and Western blot analysis. This revealed interactions between the membrane subunits FruF and FruG with FruE, which in vivo is located on the external side of the membrane, and with the cytoplasmatic ATPase FruK. This is in line with the proposed model for bacterial ABC sugar transporters.
Journal of Biological Chemistry 11/2011; 287(1):357-67. · 4.77 Impact Factor
