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1.
F18+ Escherichia coli cause postweaning diarrhoea and oedema disease in newly weaned piglets. Protection against these diseases can be established by preventing the fimbrial adhesion of these bacteria to the enterocytes of the porcine intestine. To test a vaccine against F18+ E. coli consisting of the adhesin of F18 fimbriae, FedF, the conservation of the FedF subunit had to be examined. Therefore, the fedF sequence of 37 F18+ E. coli isolates from different countries was determined and compared to the fedF gene of the F18ab reference strain F107/86. The amino acid sequence of the mature FedF from the individual F18+ E. coli isolates was 96–100% identical to that from E. coli F107/86, but the overall homology was 90.4%. Hyper variable regions were not found in the FedF sequence. The FedF sequence was conserved over the different countries and between the two antigenic variants, F18ab and F18ac, suggesting that F18ab and F18ac strains have the same receptor. Furthermore, the conserved C-terminal region in the FedF adhesin suggests that the F18 fimbriae, in analogy with type 1 and P pili, are assembled by a donor strand mechanism. In conclusion, the reported conservation of FedF supports the usefulness of the fimbrial adhesin as a subunit vaccine against F18+ E. coli infection.  相似文献   

2.
Post-weaning diarrhoea and oedema disease in weaned piglets are caused by infection with F4+ or F18+ Escherichia coli strains. There is no commercial vaccine available, but it is shown that oral immunization of weaned piglets with purified F4 fimbriae induces a protective mucosal immune response. In the present study, piglets were orally and nasally immunized with purified F18 fimbriae in the presence of the mucosal adjuvant LT(R192G) or CTA1-DD, respectively. This immunization could not lead to protection against F18+ E. coli infection. The induced F18-specific immune response was directed towards the major subunit FedA and weakly towards the adhesive subunit FedF. The results of these experiments demonstrate that it is difficult to induce protective immunity against F18+ E. coli using the whole fimbriae due to the low response against the adhesin.  相似文献   

3.
Escherichia coli adhesion assays were conducted using isolated porcine peripheral blood lymphocytes, Peyer's patch lymphocytes, rectal epithelial cells or brush borders, buccal epithelial cells and brush borders from small intestinal epithelial cells. The cells and brush borders were tested for their ability to bind K88-piliated exterotoxigenic E. coliStrain M1823B (K88ac) and E. coli Strain 1476 (K-12, K88ac). Comparison of adhesive phenotypes of 37 weaned pigs as determined by the adhesion assay with small intestinal brush borders and the adherence of K88ac+ enterotoxigenic E. coli to peripheral blood lymphocytes, Peyer's patch lymphocytes and rectal epithelial cells or brush borders, revealed no correlation. In vitro adhesion of K88ac-bearing E. coli was always negative with buccal epithelial cells. K88ac strains varied in their ability to adhere to lymphocytes and rectale pithelial cells or brush borders, indicating that the mechanism of adherence is unrelated to K88-mediated adhesion observed in animals that had the receptors on small-intestinal epithelial-cell brush borders. The non-piliated control E. coli Strain 123 adhered to fresh peripheral blood lymphocytes, and less intensively to frozen-thawed peripheral blood lymphocytes or Peyer's patch lymphocytes. It was concluded that none of the cell types or brush borders, except small-intestinal epithelial-cell brush borders, could be used as targets for phenotyping pigs for the presence of the K88 receptors that have been associated with adhesion and colonization of K88+ enterotoxigenic E. coli in the porcine small intestine.  相似文献   

4.
为探究撒坝猪源大肠杆菌（E.coli）高致病性毒力岛（HPI）诱导小鼠病理损伤的超微结构特征,本研究将实验室保存的E.coli HPI阳性株（HPI+）和E.coli HPI基因缺失株（ΔHPI）进行复苏和培养,分别用E.coli HPI+、E.coli ΔHPI菌株以腹腔接种的方式感染昆明小鼠,检测菌株的半数致死量（50% lethal dose,LD50）,通过HE染色和透射电镜观察并分析菌株对小鼠病理损伤的超微结构特征,利用免疫组织化学标记白细胞介素-1β（interleukin-1β,IL-1β）阳性细胞在被感染小鼠肝脏和肾脏组织中的分布,以反映E.coli HPI+及E.coli ΔHPI菌株所引起炎症水平的差异。结果显示,E.coli HPI+和E.coli ΔHPI菌株的半数致死量分别为1×107.39和1×108.62 CFU/mL;HE染色显示,E.coli感染小鼠后,可见肝脏细胞肿胀、变性,肝窦淤血,肾脏间质淤血,肾小管上皮细胞变性脱落等病理变化;超微结构变化显示,肝脏细胞的完整形态消失,胞核呈不规则形态,线粒体畸形,粗面内质网上核糖体脱落,滑面内质网增生;多数肾小管上皮细胞出现胞核固缩,部分细胞核核仁边移、体积增大,足突融合,系膜细胞间隙变宽。此外,E.coli HPI+感染组小鼠于肝脏、肾脏的水肿现象较E.coli ΔHPI菌株感染的小鼠更为明显。免疫组化结果显示,大肠杆菌感染小鼠后,IL-1β蛋白主要表达于肝细胞、中央静脉周围、肾间质细胞和肾小管上皮细胞,且E.coli HPI+感染组的IL-1β表达量高于E.coliΔHPI感染组。综上所述,撒坝猪源E.coli HPI能够调控E.coli对小鼠的致病性,HPI的调控作用可使E.coli对小鼠肝脏、肾脏造成的病变及超微结构变化更明显,并且能够增加小鼠的炎症反应。  相似文献   

5.
The hypothesis that altered behavior is a sign for an early recognition of disease was tested. The experiment was conducted to evaluate the behavioral patterns of pigs in a model of postweaning colibacillosis. Twenty-five weaned pigs (from a herd that was previously found to be highly susceptible to F4+ Escherichia coli strains) were randomly assigned into 5 groups, kept in isolated pens under the controlled ambiental conditions. One day after weaning, the pigs from three groups were intragastrically inoculated (via orogastric tube) with either F4ac+ (1466 or 2407) or F4− (1467) nonenterotoxigenic E. coli (non-ETEC) strains, respectively. The pigs from the fourth group were inoculated with F4ac+ ETEC strain M1823 and the remaining 5 pigs that received broth containing 1.2% sodium bicarbonate were kept as noninoculated controls. The pigs were examined daily and the frequency and duration of their behavioral patterns, such as eating, drinking, lying, standing, urinating, defecating, rooting and playing were monitored for 300 h during a period of 10 days. In this model, three conditions were also observed in F4-susceptible pigs: (1) acute fatal diarrheal disease; (2) moderate diarrhea and weight loss and (3) no diarrhea and weight loss. The incidence (both frequency and duration) of defecating was significantly higher (P<0.05) in pigs inoculated with F4ac+ ETEC strain M1823 as compared to that of noninoculated (control) pigs. Pigs inoculated with F4ac+ non-ETEC strain 1466 had a significantly lower frequency of eating (P<0.05) and frequency/duration of drinking (P<0.05) than did the controls. The 1466-inoculated pigs, had an increased diarrhea score, but frequency/duration of defecating was not significantly different. Pigs inoculated with F4ac+ non-ETEC strain 2407 spent more time in lying (P<0.05) than did noninoculated pigs. Conversely, the pigs that received F4− non-ETEC strain 1467 laid shorter (P<0.05) and ate/drank less frequently (P<0.05) than the controls. It was concluded that the changed occurrence of defecating and eating in pigs that were inoculated with either F4ac+ ETEC (M1823) or non-ETEC (1466) strain, respectively, was consistent with the pending clinical disease, i.e. postweaning colibacillosis.  相似文献   

6.
试验旨在研究大肠杆菌（E.coli）对奶牛子宫内膜上皮细胞（bovine endometrial epithelial cells,BEECs）的体外炎性损伤,探究大肠杆菌引发炎性反应的最佳浓度、作用时间及机制。首先,用不同浓度的大肠杆菌（5×104、5×105、1×106、2.5×106、5×106 CFU/mL）诱导刺激细胞3、6和9 h,通过倒置显微镜观察细胞形态、CCK-8法测D450 nm值,检测大肠杆菌对细胞活性的影响;其次,用不同浓度的大肠杆菌（5×104、5×105 CFU/mL）处理细胞3、6和9 h,用ELISA方法检测细胞上清液中白介素-1β（IL-1β）、IL-6、IL-8和肿瘤坏死因子-α（TNF-α）的分泌量;最后,用不同浓度的大肠杆菌（5×104、5×105 CFU/mL）处理细胞6和9 h,用Western blotting检测核因子κB抑制蛋白α（IκBα）和p65蛋白的磷酸化水平。结果显示,与对照组相比,大肠杆菌感染细胞9 h后,1×106、2.5×106和5×106 CFU/mL大肠杆菌组细胞活性均极显著降低（P<0.01）,5×105 CFU/mL大肠杆菌组显著降低（P<0.05）;大肠杆菌感染细胞9 h后,5×105 CFU/mL大肠杆菌组IL-1β、IL-6、IL-8和TNF-α极显著升高（P<0.01）;大肠杆菌感染细胞6 h后,5×105 CFU/mL大肠杆菌组IκBα、p65蛋白磷酸化水平和IL-6均极显著升高（P<0.01）,5×104 CFU/mL大肠杆菌组IκBα和p65蛋白磷酸化水平显著升高（P<0.05）。结果表明,大肠杆菌可以刺激奶牛子宫内膜上皮细胞产生炎性反应,且当细胞与5×105 CFU/mL大肠杆菌作用6 h或与5×104 CFU/mL大肠杆菌作用9 h为最佳。  相似文献   

7.
为研究云南撒坝猪致病性大肠杆菌高致病性毒力岛（HPI）致猪源巨噬细胞焦亡的分子机制,本试验以云南撒坝猪致病性大肠杆菌HPI阳性株感染猪源巨噬细胞为切入点,从云南楚雄州某规模养殖场采集撒坝猪仔猪黄白痢的粪便,对大肠杆菌进行分离纯化,并通过PCR技术对HPI irp2基因进行检测,分别以HPI阳性株（HPI+）和阴性株（HPI-）感染巨噬细胞,并设立LPS+ATP组和空白对照组,于0.5和6 h收集各组细胞及其上清。应用实时荧光定量PCR法检测不同组Caspase-1、IL-1β和IL-18 mRNA表达水平的变化;应用ELISA检测细胞上清pro-IL-1β、pro-IL-18、IL-1β和IL-18含量的变化。结果显示,试验成功分离得到致病性大肠杆菌,经PCR检测成功获得HPI irp2基因阳性株,经实时荧光定量PCR法检测后发现HPI+组、HPI-组与空白对照组相比,Caspase-1、IL-1β和IL-18 mRNA表达水平均呈上调趋势,且HPI+组高于HPI-组。ELISA检测结果显示,与空白对照组相比,HPI+组和HPI-组pro-IL-1β、pro-IL-18、IL-1β和IL-18的蛋白表达量普遍呈上调趋势,且HPI+组均高于HPI-组。结果表明,云南撒坝猪致病性大肠杆菌HPI可通过上调猪源巨噬细胞中Caspase-1、IL-1β和IL-18 mRNA的表达量促进猪源巨噬细胞炎性因子IL-1β和IL-18的释放,诱发炎症,最终促进猪源巨噬细胞发生细胞焦亡。  相似文献   

8.
试验旨在探索革兰氏阴性菌大肠杆菌（Escherichia coli,E.coli）及其表面分子脂多糖（LPS）诱导胰腺再生蛋白Ⅲγ（RegⅢγ）表达调控的机制。首先,用不同浓度灭活E.coli（109、108、107、106、105、104 CFU/mL）和LPS （0.01、0.1、1、5、10、20、40、80 μg/mL）诱导猪肠黏膜上皮细胞（IPEC-JⅡ）,用MTT法测D490 nm值,检测E.coli和LPS对IPEC-JⅡ细胞活力的影响;其次,用不同浓度灭活E.coli（107、106、105 CFU/mL）和LPS （0.01、0.1、1、5 μg/mL）处理IPEC-JⅡ细胞24 h,用实时荧光定量PCR和Western blotting检测RegⅢγ mRNA和蛋白的表达;最后,用1 μg/mL LPS处理IPEC-JⅡ细胞24 h,用实时荧光定量PCR和Western blotting检测p65、p38、JNK、ERK mRNA和蛋白表达及磷酸化水平。结果显示,除0.01 μg/mL LPS不抑制IPEC-JⅡ细胞活力外,其他浓度的灭活E.coli和LPS均可抑制IPEC-JⅡ细胞活力,且109、108 CFU/mL E.coli和10、20、40、80 μg/mL LPS组细胞活力极显著下降（P<0.01）;与对照组相比,107、106和105 CFU/mL E.coli均能诱导RegⅢγ表达增加,且105 CFU/mL E.coli组RegⅢγ mRNA表达量极显著高于对照组（P<0.01）,蛋白表达量显著高于对照组（P<0.05）;0.01、0.1、1和10 μg/mL LPS均能诱导RegⅢγ表达增加,且0.1和1 μg/mL LPS组RegⅢγ mRNA表达量极显著高于对照组（P<0.01）,RegⅢγ蛋白表达虽有增加趋势,但差异不显著（P>0.05）;与对照组相比,1 μg/mL LPS组p65、p38 mRNA表达量极显著增加（P<0.01）,JNK、ERK mRNA表达量显著增加（P<0.05）;同时,p38、JNK蛋白表达量和磷酸化水平均极显著增加（P<0.01）,p65蛋白磷酸化水平显著增加（P<0.05）,ERK蛋白和磷酸化水平均增加,但差异不显著（P>0.05）。以上结果表明,灭活E.coli和LPS均可诱导RegⅢγ表达,1 μg/mL LPS可增加p65、p38和JNK蛋白的磷酸化水平。  相似文献   

9.
本研究旨在探讨猪m6A甲基化酶WTAP表达水平与大肠杆菌（E. coli）感染抗性的关系。选取35日龄苏太断奶仔猪（Sus scrofa）大肠杆菌抗性型和敏感型个体各4头,采集十二指肠和空肠组织,利用RT-qPCR检测WTAP在E. coli抗性型和敏感型个体十二指肠、空肠的表达差异,并分别利用产肠毒素大肠杆菌（F18ab、F18ac）刺激和内毒素（LPS）诱导猪小肠上皮细胞（IPEC-J2）,检测WTAP基因的表达变化。同时构建WTAP基因干扰载体并转染IPEC-J2细胞,通过菌毛定量、菌落计数以及间接免疫荧光试验检测该基因沉默对大肠杆菌黏附能力的影响。结果显示：在十二指肠和空肠组织中,WTAP基因在E. coli抗性型个体中的表达量显著高于敏感型个体（P<0.01）;并且在F18ab和F18ac刺激后表达量显著下降,与LPS诱导6 h后结果相一致（P<0.01）。沉默WTAP基因后,大肠杆菌黏附能力极显著上升（P<0.01）。本研究在细胞和个体水平上验证发现,m6A甲基转移酶WTAP的高表达可能有助于仔猪抗大肠杆菌感染,为进一步揭示仔猪抗大肠杆菌感染的RNA甲基化调控机制奠定基础。  相似文献   

10.
甜叶菊绿原酸增强大肠杆菌感染蛋雏鸡免疫力研究   总被引：1，自引：0，他引：1  
旨在评价甜叶菊绿原酸增强人工腹气囊感染大肠杆菌O78蛋雏鸡免疫力的作用效果,为功能性抗生素替代品研发提供基础参数支持。本试验随机将1日龄、体重无显著差异的健康海兰蛋鸡360只分为6组：空白对照组（C）、大肠杆菌O78处理组（EC0）、1.0 g·L-1杜仲素+大肠杆菌O78处理组（ED1）、1.0 g·L-1甜叶菊绿原酸+大肠杆菌O78处理组（EC1）、2.0 g·L-1甜叶菊绿原酸+大肠杆菌O78处理组（EC2）、4.0 g·L-1甜叶菊绿原酸+大肠杆菌O78处理组（EC4）,预饲7 d后开始正式试验。第7天时将大肠杆菌O78通过腹气囊感染蛋雏鸡,饮水投喂药物,每天1次,连用3 d。随后通过ELISA法检测血清IL-1β、IL-2、IL-6、IgM、IgA、TNF-α水平;RT-qPCR检测空肠和回肠IL-1β、IL-2、TNF-α、Claudin-1和ZO-1基因表达;高通量测序分析盲肠内容物微生物种类。结果显示：1）腹气囊感染大肠杆菌O78显著增加了蛋雏鸡死亡率（P<0.05）,而甜叶菊绿原酸处理组（EC2、EC4）蛋雏鸡的死亡率显著降低（P<0.05）。2）甜叶菊绿原酸对大肠杆菌O78感染蛋雏鸡血清IgA和IgM含量有提高趋势,可不同程度降低血清炎性因子含量,其中EC1、EC2、EC4组血清TNF-α含量显著降低（P<0.05）;EC2显著降低大肠杆菌O78感染蛋雏鸡回肠促炎细胞因子IL-1β、IL-2、TNF-α的基因表达（P<0.05）。3）甜叶菊绿原酸可促进蛋雏鸡空肠紧密连接蛋白基因表达,改善腹气囊感染大肠杆菌O78对肠道屏障的损伤。4）腹气囊感染大肠杆菌O78导致鸡肠道特有OTUs增加,增加肠道拟杆菌门、变形菌门和梭杆菌门的相对丰度,降低厚壁菌门的相对丰度;而甜叶菊绿原酸处理组（EC2）蛋雏鸡盲肠厚壁菌门的相对丰度升高,拟杆菌门和变形菌门的相对丰度降低。甜叶菊绿原酸可增强腹气囊感染大肠杆菌O78蛋雏鸡机体的免疫功能,抵御大肠杆菌O78对蛋雏鸡的侵袭,其中应用剂量为2.0 g·L-1甜叶菊绿原酸的效果较好。这预示绿原酸具有抗生素替代品的功效,其对大肠杆菌感染蛋雏鸡机体免疫力的积极作用可能是通过调控免疫相关基因和维持盲肠微生物菌群稳态达到的,但其作用机制仍需深入的研究。  相似文献   

11.
本试验旨在建立一种乳品中大肠杆菌PMA-qPCR活菌检测方法.优化qPCR检测方法,探究菌浓度为1×108 CFU/mL的大肠杆菌活菌悬液、热致死菌悬液细胞数来确定不同的PMA剂量、暗孵育时间、曝光时间对死菌抑制效果的影响,确定最佳PMA处理方案.结果表明,qPCR检测可特异性扩增大肠杆菌,1×108 CFU/mL的大肠杆菌经90 ℃水浴30 s全部致死后,采用10 μg/mL的 PMA暗孵育15 min后冰上曝光10 min为最佳处理方案,这种处理方案可最大程度抑制死细胞信号,而对活细胞几乎没有影响,样品中微生物初始浓度不低于1×108 CFU/mL时较稳定,得到标准曲线回归方程y=-3.356x+47.413,R2=0.9989,最低检测限为103 CFU/mL,加标样本检测结果与实际相符.该方法为利用PMA-qPCR检测食品中的活大肠杆菌杆菌奠定了基础.  相似文献   

12.
In order to detect viable E.coli in milk,a new PMA-qPCR method was established.The influences of different PMA concentration,dark incubation time,exposure time on dead bacteria inhibition effect were determined by detection of the cell numbers of viable and heat-killed E.coli suspensions at concentration of 1×108 CFU/mL through fluorescence quantitative PCR (qPCR) method.The results showed that qPCR assay could specifically detect E.coli,and the viable E.coli must be exposed to 90 ℃ for 30 s in water bath to be lethal.The best treatment was 10 μg/mL PMA with 15 min of dark incubation time and 10 min of exposure time.This treatment could inhibit dead cell signals to a largest extend,while had little impact on aviable cells.The stability of PMA-qPCR assay was kept while the concentration of bacteria was more than 1×108 CFU/mL.The regression equation of standard curve was y=-3.356x+47.413,R2=0.9989,the lowest detection limit was 103 CFU/mL.The result of adding assay was agreed with the actual situation.This study laid a foundation for using of PMA-qPCR to detect the viable E.coli in food.  相似文献   

13.
为了探讨猪6-甲基腺嘌呤（m6A）去甲基化酶mRNA表达水平与仔猪大肠杆菌F18抗性的关系,本研究运用实时荧光定量PCR方法检测m6A去甲基化酶FTO和ALKBH5基因在35日龄苏太猪断奶仔猪大肠杆菌F18抗性型和敏感型个体十二指肠和空肠组织中的mRNA表达差异,同时分别利用F18ab、F18ac大肠杆菌菌体刺激和内毒素LPS诱导猪小肠上皮细胞（IPEC-J2）,检测FTO、ALKBH5基因表达变化。结果表明,FTO、ALKBH5基因在抗性型个体十二指肠和空肠中的表达量均极显著或显著高于敏感型个体（P<0.01,P<0.05）;不同F18大肠杆菌菌体刺激IPEC-J2细胞后,FTO基因表达水平均无显著变化（P>0.05）,而ALKBH5基因在F18ac刺激后表达量显著上调（P<0.05）;LPS诱导4 h时,FTO和ALKBH5基因表达量均显著上调（P<0.05）。本研究在细胞和个体水平上初步验证并发现了m6A去甲基化酶FTO和ALKBH5基因表达水平与大肠杆菌感染仔猪密切相关,为今后深入研究RNA去甲基化修饰在仔猪细菌性腹泻调控中的作用机制提供了理论基础。  相似文献   

14.
To investigate the relationship between the mRNA expression level of m6A demethylase and E.coli F18 resistance in piglets,Real-time quantitative PCR was used to detect the mRNA expression differences of m6A demethylase FTO and ALKBH5 genes in the duodenum and jejunum tissues of E.coli F18-resistant and -sensitive individuals from 35-day Sutai weaned piglets.In E.coli F18ab,F18ac bacteria-stimulated and endotoxin LPS-induced porcine small intestinal epithelial cells (IPEC-J2),the expression levels of FTO and ALKBH5 genes were detected,respectively.The results showed that the expression levels of FTO and ALKBH5 genes in the duodenum and jejunum of resistant individuals were extremely significantly or significantly higher than those of sensitive individuals (P<0.01,P<0.05),and the expression of FTO gene were not significantly changed in E.coli F18 bacteria-stimulated IPEC-J2 cells (P>0.05),but the expression levels of ALKBH5 gene were significantly up-regulated after F18ac stimulation (P<0.05).After LPS induction for 4 hours,the expression levels of FTO and ALKBH5 genes showed significant up-regulation in IPEC-J2 cells (P<0.05).This study preliminarily verified and indicated that the expression levels of m6A demethylases FTO and ALKBH5 genes were closely related to E.coli resistance of piglets at the cellular and individual levels,which will provide a theoretical basis for future in-depth study of the regulation mechanism of RNA demethylation modification on bacterial diarrhea in piglets.  相似文献   

15.
【目的】 探索噬菌体作为控制养殖环境致病性大肠杆菌的新手段。【方法】 本研究进行了大肠杆菌噬菌体的分离及相应指标评估。通过双层平板法从养殖环境中分离禽致病性大肠杆菌裂解性噬菌体。通过电镜及酶切鉴定、温度及酸碱稳定性、最佳感染复数、一步生长曲线及其在模拟环境中的杀菌效果对该噬菌体进行综合性评估。【结果】 分离得到的噬菌体具有正多面体的头部和细而长的尾部结构, 头部直径约98 nm, 尾部长约123 nm, 结合酶切鉴定结果初步判定该噬菌体为肌尾科双链DNA噬菌体。该噬菌体的温度耐受范围为37~50 ℃; 酸碱耐受范围为pH 3.0~11.0。当感染复数为0.00001时产生的子代噬菌体滴度最高; 一步生长曲线测定结果显示, 该噬菌体潜伏期为20~40 min, 裂解时间为80~100 min, 裂解量为4 133 PFU/cell。从该噬菌体对模拟环境中宿主大肠杆菌的杀菌效果可看出, 浓度为1×104~1×106 PFU/mL的噬菌体ФECP2-1对液体中目标大肠杆菌作用1~6 h, 杀菌率均在99.9%以上; 浓度为2×104~2×106 PFU/g的噬菌体ФECP2-1对鸡粪中目标大肠杆菌作用5~10 h, 杀菌率均在99%以上, 该噬菌体对鸡粪中目标大肠杆菌杀菌效果略低于对液体中目标大肠杆菌的杀菌效果。【结论】 ФECP2-1符合噬菌体类消毒剂相关特征, 是一株具有良好应用前景的噬菌体, 可作为一种生物消毒剂应用于养殖环境中禽大肠杆菌的防控。  相似文献   

16.
为了研究前列腺素D2（prostaglandin D2,PGD2）/DP1受体途径对大肠杆菌（Escherichia coli）和金黄色葡萄球菌（Staphylococcus aureus）感染奶牛子宫内膜组织中炎症介质HMGB-1和PAFR的表达及对组织损伤程度的影响,试验以体外培养奶牛子宫内膜组织为研究对象,应用1×10-6 mol/L DP1受体激动剂（BW-245C和15d-PGJ2）和等量（1×106 CFU/mL）大肠杆菌、金黄色葡萄球菌共同处理奶牛子宫内膜组织,采用实时荧光定量PCR、免疫组化和HE染色法检测奶牛子宫内膜组织中HMGB-1和PAFR的表达并评价组织损伤情况。结果显示,与空白对照组相比,大肠杆菌和金黄色葡萄球菌感染奶牛子宫内膜组织中HMGB-1和PAFR表达量显著升高（P<0.05）,而DP1受体激动剂与大肠杆菌和金黄色葡萄球菌共处理奶牛子宫内膜组织中DP1受体激动剂显著抑制奶牛子宫组织中HMGB-1和PAFR的表达（P<0.05）。HE染色结果显示,大肠杆菌与金黄色葡萄球菌感染的奶牛子宫内膜组织上皮细胞和腺上皮细胞完全脱落、坏死、崩解;而DP1受体激动剂、大肠杆菌、金黄色葡萄球菌共同处理奶牛子宫内膜组织中,DP1受体激动剂的加入显著减轻奶牛子宫内膜组织的损伤程度（P<0.05）。免疫组化染色法结果与以上两种方法结果一致。结果表明,PGD2能够抑制大肠杆菌与金黄色葡萄球菌感染的奶牛子宫内膜组织中损伤相关因子HMGB-1、PAFR的表达,减轻组织损伤程度,这一作用可能是由DP1受体所介导的。  相似文献   

17.
本试验旨在评价穿心莲内酯干混悬剂对大肠杆菌感染致肉鸡腹泻的治疗效果,为其临床应用提供试验依据。选取12日龄健康试验鸡300只,随机分为5个组,每组4个重复,每个重复15只。包括空白对照组、大肠杆菌ETECO101攻毒组、大肠杆菌攻毒加100和200 mg·L-1穿心莲内酯干混悬剂及60 mg·L-1粘菌素组。肉鸡15日龄通过腹腔注射0.2 mL含5×108 cfu·mL-1 ETECO101的生理盐水感染细菌,空白对照组腹腔注射0.2 mL生理盐水。细菌感染前3 d开始通过饮水给药,早、晚各给药1次,每次每个重复700 mL,连续给药至攻菌后第3天停止给药。每组随机选取1个重复,于攻菌后24 h和第5天分别选取6只鸡采血、剖检和取组织样,用于肝组织病理学观察、小肠微结构分析、免疫器官指数测定和血液生化指标分析。每组剩余3个重复（45只）试验至攻菌后第7天,计算存活率、粪便评分、平均日增重（ADG）和平均日采食量（ADFI）,以评价药物的药效。结果显示,相对于ETECO101组,药物含量为100和200 mg·L-1的穿心莲内酯干混悬剂组肉鸡存活率分别提高13.3和17.8个百分点（P<0.05）,减轻大肠杆菌感染导致的腹泻,显著提高肉鸡ADG （P<0.01）和ADFI（P<0.01）;200 mg·L-1穿心莲内酯干混悬剂组显著地增加了攻菌后24 h肉鸡脾脏和法氏囊指数（P<0.01）,降低了攻菌后第5天肉鸡血清中球蛋白（GLB）和白蛋白（ALB）含量（P<0.05）,有效地抑制肉鸡血清中丙二醛（MDA）含量的增加,提高肉鸡血清超氧化物歧化酶（SOD）活力（P<0.01）和谷胱甘肽过氧化物酶（GSH-Px）活力（P<0.01）。同时,200 mg·L-1穿心莲内酯干混悬剂组可显著改善肉鸡空肠绒毛高度（P<0.05）,以及绒毛高度与隐窝深度的比值。综上所述,饮水中添加穿心莲内酯干混悬剂可减少大肠杆菌感染导致的鸡死亡,改善肉鸡生长性能、血清氧化应激状态和空肠肠道形态,提高法氏囊指数,对大肠杆菌感染而导致的肉鸡腹泻具有显著疗效。  相似文献   

18.
The mutation at 307 bp (M307) of the alpha (1,2) fucosyltransferase gene has been proposed as being a marker for selection of E. coli F18 adhesion-resistant pigs. Nonetheless, exactly how this mutation affects pigs' growth performance remains unclear. This study investigated genotypic frequencies and the effect of M307 and the ryanodine receptor (RYR1) on the growth performance of two major Western pig breeds in Taiwan. In total, 1510 (1024 Duroc and 486 Landrace) boars were performance tested using segregated early weaning entrance. The genotypes of M307 and RYR1 were determined by polymerase chain reaction-based restriction fragment length polymorphism. The performance traits included average daily gain, the feed conversion ratio, backfat thickness, and age at 110 kg of body weight. The statistical model included starting age, test season, genotype of M307, genotype of RYR1, and two- and three-way interactions. The data were analyzed within breeds. Consequently, the genotypic frequencies of the AA genotype in M307 were 0.06 and 0.06, and of the GG genotype were 0.53 and 0.64 in Duroc and Landrace pigs, respectively. The genotypic frequencies of the NN genotype in RYR1 were 0.75 and 0.99, and of the nn genotype were 0.01 and 0.00 in Duroc and Landrace pigs, respectively. There was no significant effect of the M307 genotype on the growth performance in either Duroc or Landrace breeds. However, the RYR1 significantly influenced the average daily gain and age at 110 kg of body weight of Duroc pigs. The results suggest that selection of the favorable AA genotype at M307 for E. coli F18 adhesion resistance may not affect the growth performance traits in Duroc and Landrace pigs. However, the effect of the RYR1 on growth performance should be monitored during selection.  相似文献   

19.
A pilot study was carried out on a Danish swine farm infected with multi-resistant Salmonella Typhimurium DT104 (MRDT104). We aimed to (1) investigate to which degree the decline of Escherichia coli and Salmonella in swine slurry applied to farmland depended on the application method; (2) estimate the survival times of E. coli and Salmonella in the soil surface following deposition of naturally contaminated pig slurry; and (3) simulate survival of Salmonella in different infection levels using E. coli data as input estimates. Slurry was deposited by four different methods: (1) hose applicator on black soil followed by ploughing and harrowing; (2) hose applicator on black soil followed only by harrowing; (3) hose applicator on a field with winter-wheat seedlings without further soil treatment; (4) slurry injector on a field with winter-wheat seedlings without further soil treatment. E. coli and Salmonella could not be detected at all in soil following treatment 1. Following the other treatments, E. coli was not detected in soil samples after day 21 and Salmonella was no longer detected after day 7. Simulation results showed that clinical (4 log CFU g−1) and sub-clinical Salmonella levels (2500 CFU g−1) would fall below the detection limit within 10 or 5 days, respectively. Analysis of samples from 62 Danish MRDT104-infected swineherds showed that nearly 75% of these herds had low levels of MRDT104 (<10 CFU g−1) in their slurry. Our results show that ploughing and harrowing of soil amended with contaminated pig slurry was an effective means to reduce environmental exposure to E. coli and Salmonella on this clay-soil farm.  相似文献   

20.
In order to evaluate the role of the AIDA-I of porcine diarrheagenic Escherichia coli strain PD20 serogroup O143 (AIDA-I+, STb+), a mutant strain PD20M (AIDA-I−, STb+) was generated from strain PD20 by an allelic exchange procedure. In addition, the full-length aidA gene was reintroduced into strain PD20M to generate the complemented strain PD20C (pTaidA, AIDA-I+, STb+). A non-pathogenic E. coli strain PD71 was used as negative control. Each strain was inoculated to newborn pigs via stomach tube. Severity of diarrhea was evaluated clinically and intestinal colonization was assessed by histology, immunohistochemistry (IHC), and transmission electron microscopy (TEM) including immunogold electron microscopy (IGEM). The adhesion pattern to HeLa cells, bacterial auto-aggregation and biofilm formation were evaluated in vitro. Pigs infected with strains PD20 or PD20C developed diarrhea 16 and 28 h after inoculation, respectively, in contrast to pigs infected with strains PD20M or PD71. Histology, IHC, TEM and IGEM examinations showed heavy bacterial colonization with biofilm formation in the large intestine, and marked in vivo expression of AIDA-I protein in pigs infected with strains PD20 or PD20C in contrast to pigs infected with strains PD20M or PD71. The in vitro assays showed marked diffuse adherence to HeLa cells, enhanced bacterial auto-aggregation and significant biofilm formation (p < 0.05) by the AIDA-I+ strains, when compared to AIDA-I− strains. These results demonstrate that expression of AIDA-I is essential for intestinal colonization and in vitro bacterial autoaggregation and biofilm formation. Thus, AIDA-I may be considered a significant virulence determinant in development of diarrhea caused by porcine diarrheagenic AIDA-I+ E. coli PD20 in piglets.  相似文献   

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