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Search Results: 1 - 10 of 11111 matches for " Changyun Ye "
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Rapid and Sensitive Detection of Plesiomonas shigelloides by Loop-Mediated Isothermal Amplification of the hugA Gene
Shuang Meng, Jianguo Xu, Yanwen Xiong, Changyun Ye
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0041978
Abstract: Plesiomonas shigelloides is one of the causative agents of human gastroenteritis, with increasing number of reports describing such infections in recent years. In this study, the hugA gene was chosen as the target to design loop-mediated isothermal amplification (LAMP) assays for the rapid, specific, and sensitive detection of P. shigelloides. The performance of the assay with reference plasmids and spiked human stools as samples was evaluated and compared with those of quantitative PCR (qPCR). No false-positive results were observed for the 32 non-P. shigelloides strains used to evaluate assay specificity. The limit of detection for P. shigelloides was approximately 20 copies per reaction in reference plasmids and 5×103 CFU per gram in spiked human stool, which were more sensitive than the results of qPCR. When applied in human stool samples spiked with 2 low levels of P. shigelloides, the LAMP assays achieved accurate detection after 6-h enrichment. In conclusion, the LAMP assay developed in this study is a valuable method for rapid, cost-effective, and simple detection of P. shigelloides in basic clinical and field laboratories in the rural areas of China.
Enterohemorrhagic Escherichia coli Specific Enterohemolysin Induced IL-1β in Human Macrophages and EHEC-Induced IL-1β Required Activation of NLRP3 Inflammasome
Xiaoai Zhang, Yuli Cheng, Yanwen Xiong, Changyun Ye, Han Zheng, Hui Sun, Hongqing Zhao, Zhihong Ren, Jianguo Xu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0050288
Abstract: Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a major foodborne pathogen causing hemorrhagic colitis and hemolytic-uremic syndrome. The role of EHEC O157:H7-enterohemolysin (Ehx) in the pathogenesis of infections remains poorly defined. In this study, we used gene deletion and complement methods to confirm its putative functions. Results demonstrated that, in THP-1 cells, EHEC O157:H7-Ehx is associated with greater production of extracellular interleukin (IL)-1β than other cytokines. The data also showed that EHEC O157:H7-Ehx contributed to cytotoxicity in THP-1 cells, causing the release of lactate dehydrogenase (LDH). Although we observed a positive correlation between IL-1β production and cytotoxicity in THP-1 cells infected with different EHEC O157:H7 strains, our immunoblot results showed that the majority of IL-1β in the supernatant was mature IL-1β and not the pro-IL-1β that can be released after cell death. However, EHEC O157:H7-Ehx had no detectable effect on biologically inactive pro-IL-1β at the mRNA or protein synthesis levels. Neither did it affect the expression of apoptosis-associated speck-like protein containing a CARD (ASC), caspase-1, or NOD-like receptor family pyrin domain containing 3 (NLRP3). RNA interference experiments showed that EHEC O157:H7-induced IL-1β production required the involvement of ASC, caspase-1, and NLRP3 expression in THP-1 cells. Our results demonstrate that Ehx plays a crucial role in EHEC O157:H7-induced IL-1β production and its cytotoxicity to THP-1 cells. NLRP3 inflammasome activation is also involved in EHEC O157:H7-stimulated IL-1β release.
Construction of a food-grade secretion expression vector and use it for reporter protein expression in Lactococcus lactis

Qiangzheng Sun,Yanwen Xiong,Changyun Ye,Jianguo Xu,

微生物学报 , 2008,
Abstract: We constructed a food-grade secretion expression vector and used it for reporter protein expression in live delivery vehicle L lactisMBP71. The p32 fragment, which containing the stronger p32 promoter,,was amplified by polymerase chain reaction(PCR) with the plasmid pMG36e as template. After being purified, the p32 fragment was ligated with SPusp45 fragment amplified from genomic DNA of L lactis MG1363. The fusion fragment p32-SPusp45 was inserted into the food-grade vector pSH91 to construct a secretion expression vector, pSQ. The coding sequence of NucA (nucA) was also amplified from Staphylococcus aureus chromosome and inserted into pSQ under the control of p32 promoter to construct a recombinant plasmid pSQ-nucA. Nuclease plate activity assay and zymograme assay demonstrate that NucA was secretion expressed from L lactis harboring the recombinant plasmid pSQ- nucA, and the quantity of NucA secreted into supernamant was about ten times more than which in cell lysate. Results also indicate that expression efficiency of L lactis/pSQ-nucA was higher than that of L lactis/pSQZ-nucA, constructed by us earlier.
Low-power Wireless Pressure Transmitter and Net of Oil-well Based on Zigbee
Xiwei Yang,Changyun Li
International Journal of Information Technology and Computer Science , 2010,
Abstract: The paper introduced a low-power wireless pressure transmitter for measure pressure and temperature of oil-well. To avoid wiring cables onsite, ZICM2410 was adopted to construct Wireless Sensor Network (WSN), and powered by Li-Ion battery. To reduce the power consumption, MSP430F477 and other low-power chips were used to construct the hardware, and energy conservation strategies were designed in the software. One strategy was turning off the power when some chips or modules were not on duty. Another strategy was working, sleeping and timer waking up. The SNAP wireless network solution of Zigbee was used to compose WSN. By analysis and test, the power consumption of the transmitter is very low, and the transmission range of it could be up to 300m. It could longtime continuously work for the low power consumption ability. The transmitter could fully meet the actual requirements, and could be applied to other industry situations easily.
Identification of Genes and Genomic Islands Correlated with High Pathogenicity in Streptococcus suis Using Whole Genome Tilling Microarrays
Xiao Zheng,Han Zheng,Ruiting Lan,Changyun Ye,Yiting Wang,Ji Zhang,Huaiqi Jing,Chen Chen,Mariela Segura,Marcelo Gottschalk,Jianguo Xu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0017987
Abstract: Streptococcus suis is an important zoonotic pathogen that can cause meningitis and sepsis in both pigs and humans. Infections in humans have been sporadic worldwide but two severe outbreaks occurred in China in recent years, while infections in pigs are a major problem in the swine industry. Some S. suis strains are more pathogenic than others with 2 sequence types (ST), ST1 and ST7, being well recognized as highly pathogenic. We analyzed 31 isolates from 23 serotypes and 25 STs by NimbleGen tiling microarray using the genome of a high pathogenicity (HP) ST1 strain, GZ1, as reference and a new algorithm to detect gene content difference. The number of genes absent in a strain ranged from 49 to 225 with a total of 632 genes absent in at least one strain, while 1346 genes were found to be invariably present in all strains as the core genome of S. suis, accounting for 68% of the GZ1 genome. The majority of genes are located in chromosomal blocks with two or more contiguous genes. Sixty two blocks are absent in two or more strains and defined as regions of difference (RDs), among which 26 are putative genomic islands (GIs). Clustering and statistical analyses revealed that 8 RDs including 6 putative GIs and 21 genes within these RDs are significantly associated with HP. Three RDs encode known virulence related factors including the extracellular factor, the capsular polysaccharide and a SrtF pilus. The strains were divided into 5 groups based on population genetic analysis of multilocus sequence typing data and the distribution of the RDs among the groups revealed gain and loss of RDs in different groups. Our study elucidated the gene content diversity of S. suis and identified genes that potentially promote HP.
Genesis of a novel Shigella flexneri serotype by sequential infection of serotype-converting bacteriophages SfX and SfI
Qiangzheng Sun, Ruiting Lan, Yiting Wang, Jianping Wang, Xia Luo, Shaomin Zhang, Peijing Li, Yan Wang, Changyun Ye, Huaiqi Jing, Jianguo Xu
BMC Microbiology , 2011, DOI: 10.1186/1471-2180-11-269
Abstract: A new S. flexneri serotype-serotype 1 d was generated when a S. flexneri serotype Y strain (native LPS) was sequentially infected with 2 serotype-converting bacteriophages, SfX first and then SfI. The new serotype 1 d strain agglutinated with both serotype X-specific anti-7;8 grouping serum and serotype 1a-specific anti- I typing serum, and differed from subserotypes 1a, 1b and 1c. Twenty four S. flexneri clinical isolates of serotype X were all converted to serotype 1 d by infection with phage SfI. PCR and sequencing revealed that SfI and SfX were integrated in tandem into the proA-yaiC region of the host chromosome.These findings suggest a new S. flexneri serotype could be created in nature. Such a conversion may be constrained by susceptibility of a strain to infection by a given serotype-converting bacteriophage. This finding has significant implications in the emergence of new S. flexneri serotypes in nature.Shigella is the primary pathogen causing bacillary dysentery in developing countries. There are an estimated 164.7 million people worldwide infected by Shigella annually; resulting in 1.1 million deaths, most being children under five years [1]. A more recent study estimated approximately 125 million annual shigellosis cases and 14,000 related deaths in Asia [2], suggesting that the death rate has decreased significantly in recent years. Among the four Shigella species, S. dysenteriae, S. flexneri, S. boydii, and S. sonnei, S. flexneri is the predominant species [3].S. flexneri serotyping are based on structure of the O-antigen lipopolysaccharide. There are 15 known serotypes: 1a, 1b, 1c, 2a, 2b, 3a, 3b, 4a, 4b, 5a, 5b, 6, X, Xv and Y [4,5]. Except for serotype 6, all share a common tetrasaccharide backbone of repeating units of N-acetylglucosamine-rhamnose-rhamnose-rhamnose [6]. By adding glucosyl and/or O-acetyl groups to one or more of the sugars on the tetrasaccharide unit, various serotypes are formed. Serotype Y possesses the primary basic O-antigen w
Genetic diversity and molecular typing of Listeria monocytogenes in China
Yan Wang, Ailan Zhao, Renfa Zhu, Ruiting Lan, Dong Jin, Zhigang Cui, Yonglu Wang, Zhenchuan Li, Yiting Wang, Jianguo Xu, Changyun Ye
BMC Microbiology , 2012, DOI: 10.1186/1471-2180-12-119
Abstract: Two hundred and twelve isolates of L. monocytogenes from food sources from 12 provinces/cities in China were analysed by serotyping, Pulsed Field Gel Electrophoresis (PFGE) and Multi-locus Sequence Typing (MLST). The predominant serotypes are 1/2a, 1/2b and 1/2c accounting for 90.1% of the isolates. PFGE divided the isolates into 61 pulse types (PTs). Twenty nine PTs were represented by more than one isolates with PT GX6A16.0004 containing the most number of isolates. MLST differentiated the isolates into 36 STs, among which 15 were novel. The 3 most common STs were ST9 (29.1%), ST8 (10.7%) and ST87 (9.2%), accounting for 49.0% of the isolates.STs prevalent in other parts of the world are also prevalent in China including 7 STs (ST1-ST3, ST5, ST6, ST8, ST9) which caused maternal fetal infections or outbreaks, suggesting that these STs potentially can also cause severe human infections or outbreaks in China. Surveillance of these STs will provide important information for prevention of listeriosis. This study also enhances our understanding of genetic diversity of L. monocytogenes in China.
An O Island 172 Encoded RNA Helicase Regulates the Motility of Escherichia coli O157:H7
Yanmei Xu, Xuefang Xu, Ruiting Lan, Yanwen Xiong, Changyun Ye, Zhihong Ren, Li Liu, Ailan Zhao, Long-Fei Wu, Jianguo Xu
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0064211
Abstract: Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 is a major cause of zoonotic food- and water-borne intestinal infections worldwide with clinical consequences ranging from mild diarrhoea to hemolytic uraemic syndrome. The genome of EHEC O157:H7 contains many regions of unique DNA that are referred to as O islands including the Shiga toxin prophages and pathogenicity islands encoding key virulence factors. However many of these O islands are of unknown function. In this study, genetic analysis was conducted on OI-172 which is a 44,434 bp genomic island with 27 open reading frames. Comparative genome analysis showed that O1-72 is a composite island with progressive gain of genes since O157:H7 evolved from its ancestral O55:H7. A partial OI-172 island was also found in 2 unrelated E. coli strains and 2 Salmonella strains. OI-172 encodes several putative helicases, one of which (Z5898) is a putative DEAH box RNA helicase. To investigate the function of Z5898, a deletion mutant (EDL933ΔZ5898) was constructed in the O157:H7 strain EDL933. Comparative proteomic analysis of the mutant with the wild-type EDL933 found that flagellin was down-regulated in the Z5898 mutant. Motility assay showed that EDL933ΔZ5898 migrated slower than the wild-type EDL933 and electron microscopy found no surface flagella. Quantitative reverse transcription PCR revealed that the fliC expression of EDL933ΔZ5898 was significantly lower while the expression of its upstream regulator gene, fliA, was not affected. Using a fliA and a fliC promoter – green fluorescent protein fusion contruct, Z5898 was found to affect only the fliC promoter activity. Therefore, Z5898 regulates the flagella based motility by exerting its effect on fliC. We conclude that OI-172 is a motility associated O island and hereby name it the MAO island.
Anti-Obesity, Anti-Atherosclerotic and Anti-Oxidant Effects of Pu-Erh Tea on a High Fat Diet-Induced Obese Rat Model  [PDF]
Changyun Xiong, Yuanju Peng, Benying Liu, Wenrui Cui, Xuncheng Liu
Journal of Biosciences and Medicines (JBM) , 2019, DOI: 10.4236/jbm.2019.72010
Abstract: Pu-erh tea, a traditional Chinese beverage, has been believed to have many benefits to human health and without side effects. In this study, we systematically analyzed the main active components of Pu-erh tea and investigated its anti-obesity, anti-atherosclerotic and anti-oxidant effects using an obese rat model. Obesity was induced by feeding a high-fat diet and subsequently the experimental obese mice were fed with high-fat diet supplemented with low (2.5%), medium (5%) or high (7.5%) doses of Pu-erh tea powder for 6 weeks respectively. As result, the body weight gain of the rats was decreased by medium and high doses of Pu-erh tea treatments. Furthermore, the levels of serum total cholesterol (TC), triglyceride (TG) and atherosclerosis index (AI) were significantly lowered by Pu-erh tea compared to the control group. Conversely, high density lipoproteincholesterol (HDL-C) level of the rats was significantly elevated by Pu-erh tea treatments. In addition, Pu-erh tea treatments increased the activities of anti-oxidative enzymes such as superoxide dismutase (SOD) and glutathione peroxides (GSH-Px), whereas reduced the level of lipid peroxidation product malondialdehyde (MDA) in obese rats. Collectively, our find-ings revealed that Pu-erh tea exerts comprehensive benefits in anti-obesity, anti-atherosclerotic and anti-oxidant effects, therefore can be used as a promising functional food in obesity management.
A Novel Escherichia coli O157:H7 Clone Causing a Major Hemolytic Uremic Syndrome Outbreak in China
Yanwen Xiong, Ping Wang, Ruiting Lan, Changyun Ye, Hua Wang, Jun Ren, Huaiqi Jing, Yiting Wang, Zhemin Zhou, Xuemei Bai, Zhigang Cui, Xia Luo, Ailan Zhao, Yan Wang, Shaomin Zhang, Hui Sun, Lei Wang, Jianguo Xu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0036144
Abstract: An Escherichia coli O157:H7 outbreak in China in 1999 caused 177 deaths due to hemolytic uremic syndrome. Sixteen outbreak associated isolates were found to belong to a new clone, sequence type 96 (ST96), based on multilocus sequence typing of 15 housekeeping genes. Whole genome sequencing of an outbreak isolate, Xuzhou21, showed that the isolate is phylogenetically closely related to the Japan 1996 outbreak isolate Sakai, both of which share the most recent common ancestor with the US outbreak isolate EDL933. The levels of IL-6 and IL-8 of peripheral blood mononuclear cells induced by Xuzhou21 and Sakai were significantly higher than that induced by EDL933. Xuzhou21 also induced a significantly higher level of IL-8 than Sakai while both induced similar levels of IL-6. The expression level of Shiga toxin 2 in Xuzhou21 induced by mitomycin C was 68.6 times of that under non-inducing conditions, twice of that induced in Sakai (32.7 times) and 15 times higher than that induced in EDL933 (4.5 times). Our study shows that ST96 is a novel clone and provided significant new insights into the evolution of virulence of E. coli O157:H7.
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