ObjectiveTo characterize two strains of street rabies virus (RABV) isolated from the brain tissue of cattle from Inner Mongolia. Differences in the histopathological and ultrastructural changes in the brain tissue of infected mice were determined to reveal variation in the pathogenesis of infection between street rabies virus strains. MethodsTen-day-old mice were intracranially inoculated with one of three virus strains and brain tissue harvested when the mice were moribund. Various histopathological and ultrastructural markers of disease were then compared between the groups. ResultsInfection with the street virus strain CNM1101C resulted in severe neuronal dendrites damage, but only mild cell apoptosis, T lymphocyte infiltration and microglial activation. Infection with the other street virus strain,CNM1103C, was characterized by cell apoptosis, T lymphocyte infiltration and microglial activation as well as dendrites damage. However, in comparison, infection with the attenuated virus strain CTN caused severe T lymphocyte infiltration, microglial activation and cell apoptosis, but left the neuronal dendrites intact. ConclusionThe two street rabies virus strains isolated from cattle from Inner Mongolia had different levels of virulence and caused distinct pathological changes in infected mice. Therefore, we concluded that different pathogenic mechanisms exist between different RABV strains.
ObjectiveTo prepare the 4 candidate vaccine strains of H5N1 avian influenza virus isolated in China. MethodsRecombinant viruses were rescued using reverse genetics. Neuraminidase (NA) and hemagglutinin (HA) segments of the A/Xinjiang/1/2006, A/Guangxi/1/2009, A/Hubei/1/2010, and A/Guangdong/1/2011 viruses were amplified by RT-PCR. Multibasic amino acid cleavage site of HA was removed and ligated into the pCIpolI vector for virus rescue. The recombinant viruses were evaluated by trypsin dependent assays. Their embryonate survival and antigenicity were compared with those of the respective wild-type viruses. ResultsThe 4 recombinant viruses showed similar antigenicity compared with wild-type viruses, chickenembryo survival and trypsin-dependent characteristics. ConclusionThe 4 recombinantviruses rescued using reverse genetics meet the criteria for classification of low pathogenic avian influenza strains, thus supporting the use of them for the development of seeds and production of pre-pandemic vaccines.
ObjectiveThis study is aimed to develop a two-tube melting curve-based multiplex real time PCR assay (MCMRT-PCR) for the simultaneous detection of six common foodborne pathogenic bacteria (diarrhoeagenic Escherichia coli, Salmonella,andShigellain tube 1, Staphylococcus aureus,Vibrio parahaemolyticus, and Listeria monocytogenesin tube 2). MethodsA two-tube MCMRT-PCR assaywas performed on 7900HT Fast Real-Time PCR System (Applied Biosystems, USA). Amplification by PCR was optimized to obtain high efficiency. The sensitivity and specificity of assays were investigated. ResultsThe detection limit of optimized MCMRT-PCR assay was 3.9×102 CFU/mLforS. aureus, 4.4×102 CFU/mL for L. monocytogenes, 3.0×102 CFU/mL forSalmonella, 2.5×102 CFU/mL forShigella, 2.1×102 CFU/mL forV. parahaemolyticus, and 1.2×102 CFU/mL forE.coli. The feasibility of MCMRT-PCR was further evaluated using artificially contaminated milk, the sensitivity was at the level of 105 CFU/mL. ConclusionA two-tube MCMRT-PCR assay using six primer sets was developed for detection of multiple pathogens. Our findings demonstrates that the proposed two-tube assay is reliable, useful and rapid for simultaneous detection of six foodborne pathogenic bacteria with an intended application in provincial Centers for Diseases Control and Prevention (CDC).
ObjectiveTo investigate thecorrelation betweenregulatory T(Treg) cellsand postmenopausal osteoporosis andthe antiosteoporotic effect of 1,25-dihydroxyvitamin D3[1,25(OH)2D3] in relation to Treg cells. MethodsFifty femaleBALB/c mice were randomly divided into five groups: the basal control (BAS), Sham,ovariectomy (OVX),OVX+diethylstilbestrol (OVX+DES), andOVX+1,25(OH)2D3.Tibias were harvested andprocessed with decalcification for quantitative bone histomorphometry.Femurs were stained by immunohistochemistry to detectFoxp3 protein expression.Spleens wereused to detect Treg andFoxp3 gene expressionby flow cytometry andquantitative RT-PCR, respectively. ResultsIn comparison withthe Sham group,a significant decrease was found inthe OVX group in such indices as trabecular bone volume/total tissue area (BV/TV), trabecularnumber (Tb.N) and trabecular thickness (Tb.Th).1,25(OH)2D3andDESpartlyprevented the decrease in BV/TV, Tb.N, Tb.Th inOVX mice.Treg cell number, Foxp3 mRNA expression in spleen andFoxp3 protein expression in femur significantly decreasedinthe OVX-treated group compared withthose in thesham group.1,25(OH)2D3 andDES significantlyincreased Treg cell number andFoxp3 expression.Treg cellsand Foxp3 gene expression were related to bonehistomorphometricparameters. ConclusionThedecrease inTreg cell numbersis relevant to the postmenopausal osteoporosis. The antiosteoporosis of1,25(OH)2D3 is related to regulatory T cells.
ObjectiveTo assess the effect of atorvastatin on lipopolysaccharide(LPS)-inducedTNF-α production in RAW264.7 macrophages. MethodsRAW264.7 macrophageswere treated in different LPS concentrations oratdifferent time points with or without atorvastatin. TNF-α level in supernatant was measured. Expressions of TNF-αmRNA and protein and heme oxygenase-1 (HO-1) were detected by ELISA, PCR, and Western blot, respectively. HOactivity was assayed. ResultsLPS significantly increased the TNF-α expression and secretion in a dose- and time-dependent manner. The HO-1activity and HO-1 expression level were significantly higher after atorvastatin treatment than before atorvastatin treatment and attenuated by SB203580 and PD98059 but not by SP600125, suggesting that the ERK and p38 mitogen-activated protein kinase (MAPK) pathways participate inregulating the above-mentioned effects of atorvastatin. Moreover, the HO-1 activity suppressed by SnPP or the HO-1 expression inhibited by siRNA significantly attenuated the effect of atorvastatin onTNF-α expression and production in LPS-stimulated macrophages. ConclusionAtorvastatin can attenuate LPS-induced TNF-α expression and production by activating HO-1 via the ERK and p38 MAPK pathways,suggesting that atorvastatin can be used in treatment of inflammatory diseases such as sepsis, especially in those with atherosclerotic diseases.
ObjectivePoisonous plants are a deadly threat to public health in China. The traditional clinical diagnosis of the toxic plants isinefficient, fallible, and dependent upon experts. In this study, we tested the performance of DNA barcodes for identification of the most threatening poisonous plants in China. MethodsSeventy-four accessions of 27 toxic plant species in 22 genera and 17 families were sampled andthree DNA barcodes (matK,rbcL, and ITS) were amplified, sequenced and tested.Three methods, Blast,pairwise global alignment (PWG)distance, and Tree-Building were tested for discrimination power. ResultsThe primer universality of all the three markers was high. Except in the case of ITS for Hemerocallisminor, the three barcodes were successfully generated from all the selected species. Among the three methodsapplied, Blast showed the lowest discrimination rate,whereasPWGDistance and Tree-Building methods were equally effective. The ITS barcode showed highest discrimination rates using the PWG Distance and Tree-Building methods. When the barcodes were combined, discrimination rates were increased for the Blast method. ConclusionDNA barcoding technique provides us a fast tool for clinical identification of poisonous plants in China.We suggestmatK,rbcL, ITS used in combination as DNA barcodes for authentication of poisonous plants.