Time filter

Source Type

Li R.,Zhongshan Entry Exit Inspection and Quarantine Bureau | Bo Y.,Hunan Academy of Inspection and Quarantine | Bo Y.,Jinan University | Lu J.,Zhongshan Entry Exit Inspection and Quarantine Bureau | And 3 more authors.
Chinese Journal of Chromatography (Se Pu) | Year: 2016

An efficient method using gas chromatography-triple quadrupole mass spectrometry for the determination of 28 phthalate ester residues in bakery foods was established. The samples were extracted with ethyl acetate, and cleaned up with neutral alumina. The separation was performed on a TR-5MS capillary column (30 m×0.25 mm×0.25 μ m) by programmed temperature vaporization (PTV) with splitless mode. Meanwhile the identification and quantification were performed by GC-MS/MS in selected reaction monitoring (SRM) mode and using the internal standard method. The calibration curves of the 27 phthalate esters showed good linearities in the range of 0.05-10 mg/L, except diisononyl ortho-phthalate (DINP) which was in the range of 0.1-20 mg/L, with the correlation coefficients not less 0.9962. The limits of detection (LODs) were 0.1-9.8 μ g/kg and the limits of quantification (LOQs) were 0.4-32.6 μ g/kg. With the proposed method, the spiked recoveries were evaluated in four types of baked foods (bread, biscuits, cakes, stuffing) at low, medium and high concentrations. The results showed that the average recoveries of the 28 PAEs were in the range of 81.0%-117%, and the relative standard deviations (RSDs, n=6) were in the range of 1.3%-13.6%. The method was successfully applied in the investigation of the PAEs distribution in baked foods. The method is suitable for the determination of the 28 PAEs in baked foods with easy operation, high accuracy and precision.


Liu G.H.,Lanzhou Veterinary Research Institute | Liu G.H.,Hunan Agricultural University | Li B.,Lanzhou Veterinary Research Institute | Li B.,Guangdong HuanongWens Animal Husbandry Co. | And 12 more authors.
Journal of Helminthology | Year: 2012

The present study examined sequence variation in four mitochondrial (mt) genes, namely cytochrome c oxidase subunits 1 (cox1) and 2 (cox2), and NADH dehydrogenase subunits 1 and 2 (nad1 and nad2) among Clonorchis sinensis isolates from different endemic regions in China, and their phylogenetic relationships with other zoonotic trematodes were reconstructed. A portion of the cox1 and cox2 genes (pcox1 and pcox2), and nad1 and nad2 genes (pnad1 and pnad2) were amplified separately from individual liver flukes by polymerase chain reaction (PCR) and the amplicons were subjected to sequencing from both directions. The intra-specific sequence variations within C. sinensis were 0-1.6% for pcox1, 0-1.4% for pcox2, 0-0.9% for pnad1 and 0-1.0% for pnad2. Phylogenetic analyses based on the combined sequences of pcox1, pcox2, pnad1 and pnad2 revealed that all the C. sinensis isolates grouped together and were closely related to Opisthorchis felineus. These findings revealed the existence of intra-specific variation in mitochondrial DNA (mtDNA) sequences among C. sinensis isolates from different geographic regions, and demonstrated that mtDNA sequences provide reliable genetic markers for phylogenetic studies of zoonotic trematodes. © 2011 Cambridge University Press.


Cai X.-Q.,Lanzhou Veterinary Research Institute | Cai X.-Q.,South China Agricultural University | Yu H.-Q.,Lanzhou Veterinary Research Institute | Yu H.-Q.,Technical Center | And 10 more authors.
Parasitology International | Year: 2012

Clonorchiasis caused by the oriental liver fluke Clonorchis sinensis is a fish-borne zoonosis endemic in a number of countries. This article describes the development of a TaqMan based real-time PCR assay for detection of C. sinensis DNA in human feces and in fishes. Primers targeting the first internal transcribed spacer (ITS-1) sequence of the fluke were highly specific for C. sinensis, as evidenced by the negative amplification of closely related trematodes in the test with the exception of Opisthorchis viverrini. The detection limit of the assay was 1. pg of purified genomic DNA, 5. EPG (eggs per gram feces) or one metacercaria per gram fish filet. The assay was evaluated by testing 22 human fecal samples and 37 fish tissues microscopically determined beforehand, and the PCR results were highly in agreement with the microscopic results. This real-time PCR assay provides a useful tool for the sensitive detection of C. sinensis DNA in human stool and aquatic samples in China and other endemic countries where O. viverrini and Opisthorchis felineus are absent. © 2011 Elsevier Ireland Ltd.


Hu S.,South China University of Technology | Yu Y.,South China University of Technology | Li R.,Zhongshan Entry Exit Inspection and Quarantine Bureau | Xia X.,Guangdong Ocean University | And 2 more authors.
Food Analytical Methods | Year: 2015

Coliforms are a major group of bacteria associated with spoilage of refrigerated pork. It is necessary to develop an efficient and fast method to detect total coliforms in chilled pork because the traditional methods are laborious and time-consuming. In this study, a quantitative real-time polymerase chain reaction (qRT-PCR) targeting the lacZ gene was developed for rapid enumeration of coliforms from chilled pork. Of the 106 strains tested, 35 coliform strains and one Shigella sonnei strain were correctly identified compared with 70 control strains which failed to amplify. Detection sensitivity was 112 CFU/g. The assay was able to detect and accurately quantify the total coliforms in chilled meat within 2 h without preenrichment. The results indicate that the real-time PCR is an efficient and time-saving method that could be adopted by the meat industry to detect coliforms to replace the traditional most probable number and the rapid coliform count plate methods. © 2015 Springer Science+Business Media New York


Cai X.Q.,South China Agricultural University | Xu M.J.,South China Agricultural University | Wang Y.H.,Zhongshan Entry Exit Inspection and Quarantine Bureau | Qiu D.Y.,Zhongshan Entry Exit Inspection and Quarantine Bureau | And 6 more authors.
Parasitology Research | Year: 2010

The fish-borne clonorchiasis caused by the oriental liver fluke Clonorchis sinensis is endemic in a number of countries with over 35 million people being infected globally. Rapid and accurate detection of C. sinensis in its intermediate host fish is important for the control and prevention of clonorchiasis in areas where the disease is endemic. In the present study, we established a loop-mediated isothermal amplification (LAMP) approach for the sensitive and rapid detection of C. sinensis metacercariae in fish. The specificity and sensitivity of primers designed from the C. sinensis cathepsins B3 gene were evaluated, and specific amplification products were obtained with C. sinensis, while no amplification products were detected with DNA of related trematodes, demonstrating the specificity of the assay. The LAMP assay was proved to be 100 times more sensitive than a conventional polymerase chain reaction for detection of C. sinensis. The established LAMP assay provides a useful tool for the rapid and sensitive detection of C. sinensis in fish, which has important implications for the effective control of human clonorchiasis. © 2010 Springer-Verlag.


Hu S.,South China University of Technology | Yu Y.,South China University of Technology | Li R.,Zhongshan Entry Exit Inspection and Quarantine Bureau | Wu X.,U.S. Center for Disease Control and Prevention | And 2 more authors.
Canadian Journal of Microbiology | Year: 2016

Cronobacter sakazakii is a severe virulent strain that is frequently detected in powdered infant formula (PIF). Therefore, it is necessary to develop a fast and specific detection method. The specificity of our newly developed quantitative real-time PCR (qRT–PCR) was validated with DNA from 46 strains. Among them, 12 C. sakazakii strains were correctly amplified, whereas no positive florescent signal was observed from 34 nontarget controls. The detection limit of C. sakazakii was about 110 CFU/mL in broth and 1100 CFU/g in PIF. After enrichment in buffered peptone water for 6 h, our developed qRT–PCR assay could reliably detect C. sakazakii when the inoculation level was as low as 2 CFU/25 g (0.08 CFU/g) in PIF. The growth of C. sakazakii could be inhibited by the presence of Lactobacillus pentosus and Bacillus cereus, which used a longer enrichment period before the isolation was accomplished. However, at 5 and 50 CFU/25 g inoculation levels of C. sakazakii in the presence of 4 × 106 CFU L. pentosus/25gor of 2 × 104 CFU B. cereus/25 g, the qRT–PCR assay could detect the presence of Cronobacter even though these artificially spiked samples were negative in culture. Therefore, our results indicated that the qRT–PCR assay could detect samples containing inhibitors and could avoid false negatives by using an internal amplification control. © 2016, Canadian Journal of Microbiology. All Rights Reserved.


Yin H.,Hebei University | Guan N.,Hebei University | Dong L.,Hebei University | Yue Q.,Zhongshan Entry Exit Inspection and Quarantine Bureau | And 2 more authors.
Molecular Biology Reports | Year: 2012

Hemocyanins are copper-containing (Cu+) proteins that transport oxygen in many arthropods hemolymph. We characterized Hc1 gene from the grasshopper species Locusta migratoria manilensis. In particular, we cloned and sequenced the corresponding cDNAs and studied their expression at different developmental stages. The cDNA of Hc1 gene (GenBank accession no.: HQ213937) is 2271 bp in length and the open reading frame is 2016 bp, which encodes a 672 amino acids protein with a calculated molecular mass of 77.9 kD and the isoelectric point of 6.06. Sequence alignment analysis result showed that this gene shares 94.7% identity with Schistocerca americana EHP. In addition, analysis of quantitative RT-PCR indicated that, LmiHc1 was expressed in the embyro (24, 39, 62, 86, 144, and 193 h after hatch), nymphs (1st instar, 2nd instar, 3rd instar, 4th instar and 5th instar) and in adult. These results showed that Hc1 plays an important role in grasshopper, which may be related to an enhanced oxygen supply. Phylogenetic analysis of insecta based on Hc1 are basically consistent with the morphology.© Springer Science+Business Media B.V. 2011.


Xu M.-J.,South China Agricultural University | Xu M.-J.,Lanzhou Veterinary Research Institute | Liu Q.,Veterinary Institute | Nisbet A.J.,Moredun Research Institute | And 10 more authors.
BMC Genomics | Year: 2010

Background: Clonorchis sinensis is a zoonotic parasite causing clonorchiasis-associated human disease such as biliary calculi, cholecystitis, liver cirrhosis, and it is currently classified as carcinogenic to humans for cholangiocarcinoma. MicroRNAs (miRNAs) are non-coding, regulating small RNA molecules which are essential for the complex life cycles of parasites and are involved in parasitic infections. To identify and characterize miRNAs expressed in adult C. sinensis residing chronically in the biliary tract, we developed an integrative approach combining deep sequencing and bioinformatic predictions with stem-loop real-time PCR analysis.Results: Here we report the use of this approach to identify and clone 6 new and 62,512 conserved C. sinensis miRNAs which belonged to 284 families. There was strong bias on families, family members and sequence nucleotides in C. sinensis. Uracil was the dominant nucleotide, particularly at positions 1, 14 and 22, which were located approximately at the beginning, middle and end of conserved miRNAs. There was no significant "seed region" at the first and ninth positions which were commonly found in human, animals and plants. Categorization of conserved miRNAs indicated that miRNAs of C. sinensis were still innovated and concentrated along three branches of the phylogenetic tree leading to bilaterians, insects and coelomates. There were two miRNA strategies in C. sinensis for its parasitic life: keeping a large category of miRNA families of different animals and keeping stringent conserved seed regions with high active innovation in other places of miRNAs mainly in the middle and the end, which were perfect for the parasite to perform its complex life style and for host changes.Conclusions: The present study represented the first large scale characterization of C. sinensis miRNAs, which have implications for understanding the complex biology of this zoonotic parasite, as well as miRNA studies of other related species such as Opisthorchis viverrini and Opisthorchis felineus of human and animal health significance. © 2010 Xu et al; licensee BioMed Central Ltd.


Wu K.,Zhongshan Entry Exit Inspection and Quarantine Bureau | Yue Q.,Zhongshan Entry Exit Inspection and Quarantine Bureau | Qiu D.,Zhongshan Entry Exit Inspection and Quarantine Bureau | Qiu D.,Guangdong Entry Exit Inspection and Quarantine Bureau Technology Center | Liu D.,Zhongshan Entry Exit Inspection and Quarantine Bureau
Zootaxa | Year: 2014

One new species of Jacobsonina Hebard from China is described and illustrated: Jacobsonina erebis sp. nov.. A key to all known species in this genus, except for J. lugubris (Brunner von Wattenwyl, 1893), based on males, is provided. © 2014 Magnolia Press.


PubMed | Zhongshan Entry Exit Inspection and Quarantine Bureau and China Guangdong Entry Exit Inspection and Quarantine Bureau Technology Center
Type: Journal Article | Journal: Zootaxa | Year: 2014

One new species of Jacobsonina Hebard from China is described and illustrated: Jacobsonina erebis sp. nov.. A key to all known species in this genus, except for J. lugubris (Brunner von Wattenwyl, 1893), based on males, is provided.

Loading Zhongshan Entry Exit Inspection and Quarantine Bureau collaborators
Loading Zhongshan Entry Exit Inspection and Quarantine Bureau collaborators