一株不表达K88,K99,987P粘附因子的鸽源产毒素性大肠杆菌？…

从病鸽尸体中分离出一株大肠杆菌，通过生化试验，血清学鉴定及动物致病性试验，表明该菌是一株具有很强致病力的不表达Ｋ８８，Ｋ９９，９８７Ｐ粘附素的鸽源产毒素性大肠杆菌。     

猪霍乱沙门氏菌─大肠杆菌K88ac、LT（A~－B~＋）二联基因工程菌对仔猪的

猪霍乱沙门氏菌─大肠杆菌Ｋ８８ａｃ、ＬＴ（Ａ~－Ｂ~＋）二联基因工程菌对仔猪的免疫保护试验陈陆平（长春市农业科学院长春１３０１１１）韩文瑜，梁焕春（农牧大学基础部）将表达大肠杆菌Ｋ８８ａｃ、ＬＴ（Ａ－Ｂ＋）的双表达质粒，导入猪霍乱沙门氏菌弱毒疫苗株构建...     

仔猪腹泻、水肿病疫苗预防仔猪白痢的效果试验

仔猪白痢是猪场的常见多发病,主要发生于６～２０日龄仔猪,引起肠炎及败血症,往往导致大批死亡。采用抗菌、止泻、补糖的综合疗法颇显费时费力。近年来,用疫苗对仔猪进行主动免疫逐渐普及。仔猪腹泻、水肿病疫苗含有引起仔猪黄白痢的大肠杆菌粘附素Ｋ８８、Ｋ９９、９８７Ｐ、Ｆ４１和本地分离株抗原,可有效预防大肠杆菌及其他变异株引起的腹泻症。１　材料与方法１．１　试验用苗　仔猪腹泻、水肿病疫苗,规格为１５ｍｌ／瓶。１．２　试验猪　选产期相近的经产母猪２４头,随机分为２组,即对照组和试验组,每组１２头。１．３　试验…     

仔猪大肠杆菌腹泻、K88、K99、987P三价灭活菌苗的免疫效果

将１４０头妊娠后期的母猪分成试验组与对照组，用仔猪大肠杆菌腹泻Ｋ８８、Ｋ９９、９８７Ｐ三价灭活菌苗免疫试验组母猪，对照组不接种菌苗。结果表明，试验组母猪所生仔猪黄痢的发病率、死亡率明显降低。     

大肠肝菌K88、K99、987P、F41四粘附素联合苗的试用研究

本试验在海盐县的７个点对４１头具有连续黄痢病史的母猪在预产期前２１天左右应用大肠杆菌Ｋ８８、Ｋ９９、９８７Ｐ、Ｆ４１四粘附素联合苗进行免疫，结果受试的７个点中的５个点共计２４胎３２２头仔猪无一例黄痢发生，平均黄痢发生率为５．１％，比前一胎下降５７．５％。相应的死亡率和病死率分别为０．７％和１３．８％，比前一胎分别下降２３．５％和２４．９％。     

仔猪大肠杆菌病流行株抗性质粒的研究

对分离的２７株猪源性大肠杆菌进行抗性试验，选取１０株双抗性菌株提取质粒ＤＮＡ，电泳分析表明各菌株均存在２～４条质粒ＤＮＡ带。将２１．２２７ｋｂ和５．１４８ｋｂ质粒转化大肠杆菌ＭＣ１０６１／Ｐ３，使其获得了相应菌株的抗性，转化菌纤毛蛋白与Ｋ８８、Ｋ９９高免血清琼扩试验为阴性，证明２１．２２７ｋｂ和５．１４８ｋｂ质粒未携带Ｋ８８、Ｋ９９基因。用２１．２２７ｋｂ转化菌注射小鼠，则小鼠死亡，说明２１．２２７ｋｂ携带毒力基因。     

鸡大肠杆菌的分离、鉴定与用药原则

本文对来自本地区不同鸡场的病鸡,通过肝脏进行分离得到18株细菌,通过纯培养、革兰氏染色镜检和三糖铁试验,鉴定为大肠杆菌。对所分离的18株大肠杆菌进行血清学鉴定,其中8株为078,5株为01,2株为02,3株为035。药敏试验结果表明这18株大肠杆菌对卡那霉素和头孢哌酮高度敏感。     

河南猪源致病性大肠杆菌分离、鉴定及其生物学特性

从河南省不同地区采集腹泻死亡仔猪进行病原分离鉴定,通过对细菌形态观察、PCR检测、生化试验以及小鼠毒力试验鉴定出了8株具有致病性大肠杆菌。通过WHO推荐的Kirby-Bauer(K-B)法测定8株大肠杆菌对21种抗菌药物的耐药性,并进一步对分离的8株大肠杆菌进行运动性以及生物被膜形成特性进行比较。生化特性结果表明8株大肠杆菌对各种糖的分解能力无明显差异;耐药性结果表明8株大肠杆菌均是多重耐药菌株,并且8株大肠杆菌在半固体培养基上均具有运动性,形成较明显的运动圈;生物被膜表型检测结果表明:有4株大肠杆菌具有较强的生物膜形成能力。本试验为进一步研究河南地区大肠杆菌的流行病学和探讨生物被膜和致病性、毒力之间的相关性奠定基础。     

鹅源致病性大肠杆菌O86K61 和O44K74亚型的分离与鉴定

从湛江养鹅场发生的疑似大肠杆菌病病死鹅无菌采集病料,分离鉴定出8株大肠杆菌,其中,O86K61 4株,O44K74 3株,1株未定型,上述菌株均不产生内毒素;药敏试验结果表明,大部分菌株对阿米卡星高度敏感,对恩诺沙星、先锋霉素、磺胺嘧啶、诺氟沙星、强力霉素呈交叉耐药;对万古霉素、新霉素、呋喃唑酮中度敏感;对阿莫西林、链霉素、卡那霉素、庆大霉素、四环素不敏感。上述结果提示,同一发病鹅场存在着多种致病性大肠杆菌的血清型,并存在多重耐药。     

平凉地区仔猪大肠杆菌病流行病学调查报告

通过对平凉地区仔猪大肠杆菌病流行病学调查，证实该病在该区的流行没有明显的地区差异，四季均发。在９１０份检样中，全部分离出大肠杆菌 ，说明感染率为１００％，而且发病率达５０％以上。将分离的１０６株大肠杆菌，经血清学鉴定，证实了引起该地区仔猪大肠杆菌病的病原菌是Ｏ６４、Ｏ１０１、Ｏ１４１、Ｏ１４９、Ｋ８８、Ｋ９９六个血清型的埃希氏大肠杆菌。经药敏试验确定“仔痢王”为治疗该病的首选药物。     

Plasma vitamin K concentration in horses supplemented with several vitamin K homologs

The effect of several vitamin K homologs on plasma vitamin K concentration was determined to assess their potential as a vitamin K supplement for adult horses. Sixteen Thoroughbred horses consisting of 8 mares and 8 geldings, aged 8.4 ± 3.6 yr and weighing 520.8 ± 36.1 kg, were allocated to 4 groups (n = 4). Each group was given phylloquinone, menaquinone-4, or menadione at 58 μmol/d, or no vitamin K supplement for 7 d. Plasma samples were collected before feeding, and 2, 4, and 8 h after feeding on d 7, and plasma concentrations of phylloquinone and menaquinone-4 were determined. Plasma phylloquinone concentration was greater in the phylloquinone group than in the other groups (P < 0.001). The phylloquinone concentration quadratically increased (P < 0.001) after feeding in the phylloquinone group but no changes in the plasma phylloquinone concentration were observed after feeding in the other groups. Plasma menaquinone-4 concentration was greater (P < 0.001) in the menadione group than the other groups, including the menaquinone-4 group. Menaquinone-4 concentration did not change (P = 0.192) after feeding in each group. Menaquinone-4 has been considered the most potent vitamin K homolog for bone metabolism; therefore, the present experiment indicates that menadione is a good source of vitamin K for bone health in horses because it is the only vitamin K homolog that increased the plasma concentrations of menaquinone-4.     

产肠毒素性大肠杆菌K88与K99菌毛蛋白的串联表达

根据GenBank中发表的E.coli K88、K99基因序列,分别设计合成1对引物.利用PCR技术,以大肠杆菌C83907和C83644的质粒为模板分别扩增不含信号肽的K88及K99基因.通过分离、纯化、限制性核酸内切酶酶切,连接和转化,构建了含K88-K99串联表达载体的重组菌株BL21(DE3)(pETK88CK99).结果显示,经酶切,PCR鉴定和DNA序列分析,证实了构建的重组质粒pETK88CK99中含有K88K99融合基因,且基因序列和阅读框架均正确.经过SDS-PAGE分析,串联表达蛋白含量占菌体蛋白的40%左右,经Western blotting检测,该串联表达蛋白能被大肠杆菌K88、K99标准血清识别.结果表明,构建的重组菌株可以作为预防新生仔猪大肠杆菌性腹泻基因工程疫苗的候选菌株.     

Detection of K88 and K99 fimbrial antigens on Escherichia coli by coagglutination

Coagglutination was used to detect K88 and K99 fimbrial antigens on Escherichia coli, and results were compared to an enzyme immuno assay (EIA). When pili suspensions were tested by both methods, 28 of 66 cultures were shown to have K88 and 11 of 31 cultures had K99 antigens. No pili suspensions were positive by coagglutination that were not positive by EIA. Testing of cell suspensions gave equivalent results to pili suspensions for K99 when tested by coagglutination. Two cell suspensions reacted with the K88 coagglutination which could not be confirmed by testing of pili suspensions, while a further 20 out of 43 cultures gave equivalent results with both cell and pili suspensions for K88 when tested by coagglutination.     

K88和K99双价基因工程菌C株与E株表达效果的比较

应用ＬＢ培养基３７℃、１５０ｒ／ｍｉｎ振荡培养１７小时,室温４０００ｒ／ｍｉｎ,离心３０分钟,收集沉淀菌体,用ＰＢＳ离心洗涤一次,沉淀物重悬于适量的ＰＢＳ中。三等分菌体悬浮液分别用超声波、冻融、热休克等方法处理后,室温８０００ｒ／ｍｉｎ离心３０分钟,取上清液加入饱和硫酸铵４℃过夜,沉淀蛋白经透析,ＳｅｐｈａｄｅｘＧ－１５０过柱纯化。应用ＳＤＳ－ＰＡＧＥ、凝胶扫描测定Ｋ８８、Ｋ９９蛋白的分子量及浓度,双向免疫扩散、ｗｅｓｔｅｒｎｂｌｏｔｉｎｇ试验测定其抗原性。结果表明,热休克法分离纤毛抗原是最好的方法,从Ｃ株Ｅ株分离得到的纤毛抗原,在分子量大小及对单抗亲和反应能力方面没有明显的差异。