Background Our previous study has reported that supplementation of oligosaccharide-based polymer enhances gut health and disease resistance of pigs infected with enterotoxigenic E.coli(ETEC)F18 in a manner similar to ...Background Our previous study has reported that supplementation of oligosaccharide-based polymer enhances gut health and disease resistance of pigs infected with enterotoxigenic E.coli(ETEC)F18 in a manner similar to carbadox.The objective of this study was to investigate the impacts of oligosaccharide-based polymer or antibiotic on the host metabolic profiles and colon microbiota of weaned pigs experimentally infected with ETEC F18.Results Multivariate analysis highlighted the differences in the metabolic profiles of serum and colon digesta which were predominantly found between pigs supplemented with oligosaccharide-based polymer and antibiotic.The relative abundance of metabolic markers of immune responses and nutrient metabolisms,such as amino acids and carbohydrates,were significantly differentiated between the oligosaccharide-based polymer and antibiotic groups(q<0.2 and fold change>2.0).In addition,pigs in antibiotic had a reduced(P<0.05)relative abundance of Lachnospiraceae and Lactobacillaceae,whereas had greater(P<0.05)Clostridiaceae and Streptococcaceae in the colon digesta on d 11 post-inoculation(PI)compared with d 5 PI.Conclusions The impact of oligosaccharide-based polymer on the metabolic and microbial profiles of pigs is not fully understood,and further exploration is needed.However,current research suggest that various mechanisms are involved in the enhanced disease resistance and performance in ETEC-challenged pigs by supplementing this polymer.展开更多
Escherichia coli expressing F4 fimbriae is the major pathogenic bacteria that causes diarrhea in piglets before weaning. The adhesion of E. coli to the brush borders of the epithelial cells of piglets is the precondit...Escherichia coli expressing F4 fimbriae is the major pathogenic bacteria that causes diarrhea in piglets before weaning. The adhesion of E. coli to the brush borders of the epithelial cells of piglets is the precondition leading to diarrhea, which in turn is due to the presence of the F4 receptors determined by an autosomal recessive gene on the brush borders of the epithelial cells. In order to clarify the genetic mechanism of the adhesion, an in vitro adhesion experiment was carded out for three variants of E. coli F4 （ab, ac, and ad） in 366 piglets of three pig breeds [Landrace （LR）, Large White （LW）, and Songliao Black （SB）]. The results showed that there existed significant differences （P〈0.001） in the adhesion percentage among the three breeds. Most SB piglets were nonadhesive for all the three variants, whereas most LR piglets were adhesive. Within each breed except for LR, the proportions of the three F4 variants adhering to the brush borders differed significantly. According to the patterns of the adhesion of the three F4 variants in the three breeds, it is very likely that the three F4 variants F4ab, F4ac, and F4ad have different receptors that are controlled by three different loci.展开更多
Background： The processes of weaning and exposure to pathogenic bacteria induce stress responses, which may alter the metabolism. In this study, we investigated the changes in plasma metabolites and immune responses ...Background： The processes of weaning and exposure to pathogenic bacteria induce stress responses, which may alter the metabolism. In this study, we investigated the changes in plasma metabolites and immune responses in piglets in response to the stress induced by weaning and Escherichia coli challenge. Results： Fecal dry matter decreased （P = 0.003） and nearly half （44.4%） the piglets developed diarrhea on day 2 and 3 postweaning. The concentration of plasma immunoglobulin A was higher （P 〈 0.001） on day 11 postweaning than on day 0 or 4 postweaning. The levels of white blood cells increased continuously （P〈 0.001） from day 0 to day 11 postweaning. Differences in the percentages of neutrophils （P = 0.029） and lymphocytes （P = 0.022） were seen, but the neutrophil/lymphocyte ratio did not differ in the period after weaning. A clear separation of the metabolomic profile data for day 0 and day 4 postweaning was observed with a principal components analysis （PCA） scores plot, and the data for day 11 were located between those for day 0 and day 4 postweaning. The plasma levels of proline, taurine, and carnitine were higher, whereas those of betaine, creatine, L-arginine and acetylcarnitine were lower on day 4 postweaning than on day 0. Levels of lysophosphatidylcholine and phosphatidylcholine were either higher or lower after weaning, depending on the chain lengths or characters of these metabolites. Conclusions： Our results show a clear separation in the plasma metabolomic profiles of piglets that corresponded to the fecal responses to stress on the piglets induced by weaning or exposure to a pathogen （E. coli）. These plasma metabolite profiles suggest that the challenges induced proinflammatory responses in the piglets, resulting in postweaning diarrhea, which was associated with higher concentrations of IgA in the plasma.展开更多
The gene encoding the 18 kDa protein of Taenia solium metacestodes was amplified by RT-PCR and cloned into the pGEM-T vector for sequencing.The recombinant plasmid named pGEX-CE18 was constructed and transformed into ...The gene encoding the 18 kDa protein of Taenia solium metacestodes was amplified by RT-PCR and cloned into the pGEM-T vector for sequencing.The recombinant plasmid named pGEX-CE18 was constructed and transformed into E.coli BL21 for in vitro expression.SDS-PAGE and Western blot were employed for analyzing the recombinant protein,which was then used for development of an indirect ELISA for detection of anti-cysticercosis antibodies.The results showed that the recombinant protein of interest was 35 kDa in size,accounting for 28%of total bacteria proteins,and reacted with positive sera against cysticercosis.Using the newly-constructed indirect ELISA and a commercially available ELISA kit,paired analyses of 178 serum samples indicated that the concordant rate was 98.83%and the ELISA exhibited good specificity and sensitivity,supporting its utility and application for diagnosis of cysticercosis.展开更多
Enterohemorrhagic Escherichia coli strains (EHEC) have caused many foodborne outbreaks. Bacterivorous protozoa could remove bacteria from aquatic systems. We analyzed the ciliate protozoan population changes influence...Enterohemorrhagic Escherichia coli strains (EHEC) have caused many foodborne outbreaks. Bacterivorous protozoa could remove bacteria from aquatic systems. We analyzed the ciliate protozoan population changes influenced by EHEC co-culture in activated sludge. EHEC and non-EHEC control E. coli cells were added to activated sludge samples in microcosms. The ciliate population changes were monitored by terminal restriction fragment length polymorphism (T-RFLP) analysis. EHEC and non-EHEC fed ciliate protozoan populations were different from each other and the no bacteria added controls based on the additive main effects and multiplicative interaction model (AMMI) analysis. Ciliate species were identified by 18S rDNA clone libraries. The 18S rDNA clones from the original sludge sample were identified as Epistylis wenrichi (70%) and Prorodon teres (30%), while clones from EHEC treated sludge sample were identified as P. teres (52%), Vorticella fusca (41%), Dexitrichides pangi (5%), and Opisthonecta henneguyi (2%). This study could provide helpful information about ciliate protozoan population changes caused by different E. coli strains in wastewater treatment plants, which could be useful for preventing and tracking E. coli outbreaks.展开更多
基金supported by Pancosma SA,Geneva,Switzerland,Jastro & Shields Graduate Research Awardthe United States Department of Agriculture (USDA) National Institute of Food and Agriculture (NIFA),multistate projects W4002 and NC1202
文摘Background Our previous study has reported that supplementation of oligosaccharide-based polymer enhances gut health and disease resistance of pigs infected with enterotoxigenic E.coli(ETEC)F18 in a manner similar to carbadox.The objective of this study was to investigate the impacts of oligosaccharide-based polymer or antibiotic on the host metabolic profiles and colon microbiota of weaned pigs experimentally infected with ETEC F18.Results Multivariate analysis highlighted the differences in the metabolic profiles of serum and colon digesta which were predominantly found between pigs supplemented with oligosaccharide-based polymer and antibiotic.The relative abundance of metabolic markers of immune responses and nutrient metabolisms,such as amino acids and carbohydrates,were significantly differentiated between the oligosaccharide-based polymer and antibiotic groups(q<0.2 and fold change>2.0).In addition,pigs in antibiotic had a reduced(P<0.05)relative abundance of Lachnospiraceae and Lactobacillaceae,whereas had greater(P<0.05)Clostridiaceae and Streptococcaceae in the colon digesta on d 11 post-inoculation(PI)compared with d 5 PI.Conclusions The impact of oligosaccharide-based polymer on the metabolic and microbial profiles of pigs is not fully understood,and further exploration is needed.However,current research suggest that various mechanisms are involved in the enhanced disease resistance and performance in ETEC-challenged pigs by supplementing this polymer.
基金National Basic Research Program of China (No. 2006CB102104)National Natural Sci-ences Foundation of China (No. 30430500).
文摘Escherichia coli expressing F4 fimbriae is the major pathogenic bacteria that causes diarrhea in piglets before weaning. The adhesion of E. coli to the brush borders of the epithelial cells of piglets is the precondition leading to diarrhea, which in turn is due to the presence of the F4 receptors determined by an autosomal recessive gene on the brush borders of the epithelial cells. In order to clarify the genetic mechanism of the adhesion, an in vitro adhesion experiment was carded out for three variants of E. coli F4 （ab, ac, and ad） in 366 piglets of three pig breeds [Landrace （LR）, Large White （LW）, and Songliao Black （SB）]. The results showed that there existed significant differences （P〈0.001） in the adhesion percentage among the three breeds. Most SB piglets were nonadhesive for all the three variants, whereas most LR piglets were adhesive. Within each breed except for LR, the proportions of the three F4 variants adhering to the brush borders differed significantly. According to the patterns of the adhesion of the three F4 variants in the three breeds, it is very likely that the three F4 variants F4ab, F4ac, and F4ad have different receptors that are controlled by three different loci.
文摘Background： The processes of weaning and exposure to pathogenic bacteria induce stress responses, which may alter the metabolism. In this study, we investigated the changes in plasma metabolites and immune responses in piglets in response to the stress induced by weaning and Escherichia coli challenge. Results： Fecal dry matter decreased （P = 0.003） and nearly half （44.4%） the piglets developed diarrhea on day 2 and 3 postweaning. The concentration of plasma immunoglobulin A was higher （P 〈 0.001） on day 11 postweaning than on day 0 or 4 postweaning. The levels of white blood cells increased continuously （P〈 0.001） from day 0 to day 11 postweaning. Differences in the percentages of neutrophils （P = 0.029） and lymphocytes （P = 0.022） were seen, but the neutrophil/lymphocyte ratio did not differ in the period after weaning. A clear separation of the metabolomic profile data for day 0 and day 4 postweaning was observed with a principal components analysis （PCA） scores plot, and the data for day 11 were located between those for day 0 and day 4 postweaning. The plasma levels of proline, taurine, and carnitine were higher, whereas those of betaine, creatine, L-arginine and acetylcarnitine were lower on day 4 postweaning than on day 0. Levels of lysophosphatidylcholine and phosphatidylcholine were either higher or lower after weaning, depending on the chain lengths or characters of these metabolites. Conclusions： Our results show a clear separation in the plasma metabolomic profiles of piglets that corresponded to the fecal responses to stress on the piglets induced by weaning or exposure to a pathogen （E. coli）. These plasma metabolite profiles suggest that the challenges induced proinflammatory responses in the piglets, resulting in postweaning diarrhea, which was associated with higher concentrations of IgA in the plasma.
基金supported by National High-tech Research and Development Plan(863 Project)(2006AA10A207)
文摘The gene encoding the 18 kDa protein of Taenia solium metacestodes was amplified by RT-PCR and cloned into the pGEM-T vector for sequencing.The recombinant plasmid named pGEX-CE18 was constructed and transformed into E.coli BL21 for in vitro expression.SDS-PAGE and Western blot were employed for analyzing the recombinant protein,which was then used for development of an indirect ELISA for detection of anti-cysticercosis antibodies.The results showed that the recombinant protein of interest was 35 kDa in size,accounting for 28%of total bacteria proteins,and reacted with positive sera against cysticercosis.Using the newly-constructed indirect ELISA and a commercially available ELISA kit,paired analyses of 178 serum samples indicated that the concordant rate was 98.83%and the ELISA exhibited good specificity and sensitivity,supporting its utility and application for diagnosis of cysticercosis.
文摘Enterohemorrhagic Escherichia coli strains (EHEC) have caused many foodborne outbreaks. Bacterivorous protozoa could remove bacteria from aquatic systems. We analyzed the ciliate protozoan population changes influenced by EHEC co-culture in activated sludge. EHEC and non-EHEC control E. coli cells were added to activated sludge samples in microcosms. The ciliate population changes were monitored by terminal restriction fragment length polymorphism (T-RFLP) analysis. EHEC and non-EHEC fed ciliate protozoan populations were different from each other and the no bacteria added controls based on the additive main effects and multiplicative interaction model (AMMI) analysis. Ciliate species were identified by 18S rDNA clone libraries. The 18S rDNA clones from the original sludge sample were identified as Epistylis wenrichi (70%) and Prorodon teres (30%), while clones from EHEC treated sludge sample were identified as P. teres (52%), Vorticella fusca (41%), Dexitrichides pangi (5%), and Opisthonecta henneguyi (2%). This study could provide helpful information about ciliate protozoan population changes caused by different E. coli strains in wastewater treatment plants, which could be useful for preventing and tracking E. coli outbreaks.
