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Teng Z.,Chinese Academy of Sciences | Teng Z.,Beijing Institute of Technology | Zhang M.,State Key Laboratory for Infectious Disease Prevention and Control China CDC | Zhang M.,Chinese National Institute for Communicable Disease Control and Prevention | And 5 more authors.
Biomedical Chromatography | Year: 2015

Dragon's blood is a famous traditional Chinese medicine produced from source plants under bio- or abio-stress. Dracaena cochinchinensis (Lour.) S.C. Chen xylem (DX) is one of the most important sources of the medicine. In this work, a GC-MS method was developed for analysis of the n-hexane extracts of DX with resin (DXR) and without resin (DXW). The repeatability of the method was also investigated for a metabolite comparative study of the different xylems. About 80 components were detected, 26 of which were identified in both DXR and DXN. Three sesquiterpenes (τ-cadinol, τ-muurolon and α-cadinol) were first discovered in Dracaena cochinchinensis (Lour.) S.C. Chen. The chromatographs of the two plant materials were compared and differences of compounds were found. It showed that phytosterols showed a dramatic rise in content, and sesquiterpenes were found to be synthesized in DXR. © 2015 John Wiley & Sons, Ltd. Source


Xu Y.,State Key Laboratory for Infectious Disease Prevention and Control China CDC | Xu Y.,Chinese National Institute for Communicable Disease Control and Prevention | Xu Y.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases | Xu X.,State Key Laboratory for Infectious Disease Prevention and Control China CDC | And 20 more authors.
PLoS ONE | Year: 2013

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. © 2013 Xu et al. Source


Zhang M.,State Key Laboratory for Infectious Disease Prevention and Control China CDC | Zhang M.,Chinese National Institute for Communicable Disease Control and Prevention | Zhang M.,Beijing Institute of Technology | Zhang M.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease | And 9 more authors.
Analytical Methods | Year: 2014

The CP4 EPSPS gene is widely used in herbicide-tolerant crops/plants all over the world. In this study, a sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed and validated to quantify the amount of CP4 EPSPS expression in Nicotiana tabacum leaves. The quantification of protein was used to measure the unique peptides of the CP4 EPSPS protein. Two peptides unique to CP4 EPSPS were synthesized and labelled in H 2 18O to give 18O stable isotope labelled peptides which served as internal standards. The validated method resulted in good specificity and linearity. The intra- and inter-day precisions and accuracy for all samples were satisfactory. The results demonstrated that the novel method was sensitive and selective to quantify CP4 EPSPS in the crude extract without time-consuming pre-separation or purification procedures. © the Partner Organisations 2014. Source

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