[Show abstract][Hide abstract] ABSTRACT: Olaquindox (OLA), N-(2-hydroxyethyl)-3-methyl-2-quinoxalincarboxamide-1,4-dioxide, is an antimicrobial and growth-promoting agent for animals, which has been banned or allowed only limited use for its potential toxicity. To thoroughly understand the metabolic pathways, metabolism of OLA in rat was studied using ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry with MS(E) and mass defect filtering techniques. Twenty metabolites (M1-M20) were detected in rat feces and urine, of which nine phase I metabolites (M6, M7, M11-M16) and four phase II metabolites (M17-M20) were found in vivo for the first time. The structures of metabolites were reliably characterized on the basis of accurate mass and fragment ions in MS(E) spectra. The major metabolic pathways reported previously in pigs, including reduction of N→O groups, oxidation of the alcohol and hydrolysis, were also confirmed in this study. In addition, hydroxylation of the methyl group, N-dehydroxyethylation and glucuronidation were also proved to be the important metabolic pathways, which contribute to improving our knowledge about in vivo metabolism of OLA.
Rapid Communications in Mass Spectrometry 04/2011; 25(7):889-98. · 2.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Current vaccines to avian influenzae virus (AIV), a highly contagious disease of birds, need to be constantly updated due to the high level of variation in the target antigens. Therefore, a vaccine that could induce broad cross protection against AIV is required. The M2 membrane protein is structurally conserved amongst AIV subtypes but tends in induce a poor immune response, whereas C3d has been shown in many species to enhance immunogenicity. In this study, we investigated the potential of M2-avian C3d fusion proteins to provide effective immunity.
We fused chicken complement C3d to sM2 (M2 protein with the transmembrane region deleted) of AIV and expressed four fusion proteins, GST (Glutathione S-transferase tagged proteins in pGEX expression vector) -C3d-sM2, GST-C3d-L2-sM2, GST-C3d-L1-C3d-sM2 and GST-C3d-L1-C3d-L2-sM2 were used to immunize mice. In addition, Specific pathogen free (SPF) chickens were inoculated with the plasmids pcDNA-sM2, pcDNA-C3d-L1-C3d-L2-sM2, GST-sM2 and GST-C3d-L1-C3d-L2-sM2. The immune response was monitored by an enzyme-linked immunosorbent assay (ELISA) for sM2 antibody, and all the test animals were challenged with A/chicken/Bei Jing/WD9/98 (H9N2) virus. Results revealed that the anti-sM2 antibody in mice and chickens vaccinated with these proteins was higher than the nonfused forms of sM2, the GST-C3d-L1-C3d-L2-sM2 groups have conferred the highest 30% and 20% protection ratio in mice and chickens respectively. In addition, the pcDNA-C3d-L1-C3d-L2-sM2 also enhances the antibody responses to sM2 compared to pcDNA-sM2 in chickens, and acquired 13.3% protection ratio.
These results indicated that chicken C3d enhanced the humoral immunity against AIV M2 protein either fused proteins expressed by the prokaryotic system or with the DNA vaccine. Nevertheless, in view of the poor protection ratio for these animals, we speculated that this is not a worthy developing of vaccine in these constructs.
[Show abstract][Hide abstract] ABSTRACT: An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/ MS) method was established for the determination of methaqualone, chloropromazine, promethazine, diazepam, nitrazepam, oxazepam, temazepam, midazolam, triazolam and zolpidem residues in pork and kidney. After enzymolysis, the samples were extracted by ethyl acetate and tert-butyl methyl ether, separately. The separation of the ten sedatives was performed on a Waters Acquity UPLC system with a BEH C18 column. The mobile phases were acetonitrile (containing 0.1% formic acid) and water (containing 0.1% formic acid) at a flow rate of 0.3 mL/min. The electrospray was operated in the positive ionization mode and the ten sedatives were identified by multiple reaction monitoring (MRM) mode. The method of matrix-matched standard solution was adopted as the quantitative method. The calibration curves showed good linearity within the concentrations of 2 - 100 microg/L with the correlation coefficients r > 0. 998. The limits of detection of the ten sedatives were 0.5 microg/kg, and the limit of quantification was 1 microg/kg. The recoveries of the ten sedatives were 64.5% - 111.4% at the spiked levels of 2, 5 and 10 microg/kg. The relative standard deviations of intra- and inter-day coefficients of variation were both less than 15%. This method is simple, sensitive and accurate in the determination of sedative residues.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 01/2010; 28(1):38-42.
[Show abstract][Hide abstract] ABSTRACT: Multitemporal NOAA/AVHRR NDVI images and monthly temperature and precipitation data were obtained across Yangtze River basin
covering the period 1981–2001. The spatial and temporal patterns of NDVI are the same, while spatial analysis shows that the
NDVI is influenced by the vegetation types growing in the study regions, and NDVI presents an increasing trend during the
study period in the whole basin. The climate indicators play an important role in the changes of vegetation cover in the river
basin. In the two Indicators, temperature has a significant effect on the NDVI values than precipitation in the whole basin.
However, in the 11 subbasins, the different rules are shown in different subbasins.
KeywordsYangtze River basin-NDVIT-temperature-precipitation-time series
Geo-spatial Information Science 01/2010; 13(3):186-190.
[Show abstract][Hide abstract] ABSTRACT: In this paper, we apply lagged correlation analysis to study the effects of vegetation cover on the summer climate in different
zones of China, using NOAA/AVHRR normalized difference vegetation index (NDVI) data during the time period from 1982 to 2001
and climate data of 365 meteorological stations across China (precipitation from 1982 to 2001 and temperature from 1982 to
1998). The results show that there are positive correlations between spring NDVI and summer climate (temperature and precipitation)
in most zones of China; these suggest that, when the vegetation cover increases, the summer precipitation will increase, and
the lagged correlations show a significant difference between zones. The stronger correlations between NDVI in previous season
and summer climate occur in three zones (Mid-temperate zone, Warm-temperate zone and Plateau climate zone), and this implies
that vegetation changes have more sensitive feedback effects on climate in the three zones in China.
Geo-spatial Information Science 01/2009; 12(1):41-45.
[Show abstract][Hide abstract] ABSTRACT: The authors derived the normalized difference vegetation index (NDVI) from the NOAA/AVHRR Land dataset, at a spatial resolution
of 8km and 15-day intervals, to investigate the vegetation variations in China during the period from 1982 to 2001. Then,
GIS is used to examine the relationship between precipitation and the Normalized Difference Vegetation Index (NDVI) in China,
and the value of NDVI is taken as a tool for drought monitoring. The results showed that in the study period, China’s vegetation
cover had tended to increase, compared to the early 1980s; mean annual NDVI increased 3.8%. The agricultural regions (Henan,
Hebei, Anhui and Shandong) and the west of China are marked by an increase, while the eastern coastal regions are marked by
a decrease. The correlation between monthly NDVI and monthly precipitation/temperature in the period 1982 to 2001 is significantly
2=0.84); indicating the close coupling between climate conditions (precipitation and temperature) and land surface response
patterns over China. Examination of NDVI time series reveals two periods: (1) 1982–1989, marked by low values below average
NDVI and persistence of drought with a signature large-scale drought during the 1982 and 1989; and (2) 1990–2001, marked by
a wetter trend with region-wide high values above average NDVI and a maximum level occurring in 1994 and 1998.
Geo-spatial Information Science 01/2009; 12(2):146-153.
[Show abstract][Hide abstract] ABSTRACT: An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/ MS) method was established for the simultaneous determination of terbutaline, cimaterol, salbutamol, fenoterol, clorprenaline, ractopamine, clenbuterol, tulobuterol, penbutolol residues in animal derived foods. After enzymolysis, the samples were extracted by perchloric acid, centrifuged, neutralized, followed by liquid-liquid extraction with ethyl acetate and tert-butyl methyl ether, separately. The combined extracts were applied to a solid phase extraction MCX cartridge for cleanup. The separation of beta-agonists was performed on Waters Acquity UPLC system with a BEH C18 column (50 mm x 2.1 mm, 1.7 microm) and the gradient elution solvent of acetonitrile (containing 0.1% formic acid) and water (containing 0.1% formic acid) at a flow rate of 0.3 mL/min. The method was quantified by external standard method. The calibration curves were good linear between the peak areas and the concentrations of 0.25 - 5 microg/kg with the correlation coefficient r > 0.990. The limit of detection of the 8 beta-agonists was 0.1 microg/kg, and the limit of quantification was 0.25 microg/kg. The limit of detection of penbutolol was 0.25 microg/kg, and the limit of quantification was 0.5 microg/kg. The average recoveries from spiked animal tissues at three concentrations of 0.5, 1 and 2 microg/kg ranged 87.1% - 108.6%. The relative standard deviations of intra- and inter-batch were both less than 20%.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 12/2008; 26(6):709-13.
[Show abstract][Hide abstract] ABSTRACT: Firstly, this paper presents the concept of geospatial metadata. Then it analyses the difficulties and challenges in the management of geospatial metadata. With the example of the geospatial metadata management system in GeoStar that is a well-known domestic GIS fundamental software, the functions of the geospatial metadata management system are made clear. Finally a model of geospatial metadata management in national geospatial data clearinghouse (i.e. NGDC) is proposed.