禽源多杀性巴氏杆菌ompH基因序列分析

根据NCBI登录的序列(PMU50907)合成1对引物,用PCR方法扩增了郎德鹅多杀性巴氏杆菌ompH基因,预计扩增片段大小为1544 bp(ORF 1062 bp),但是分离菌实际测序片段大小为1537 bp(ORF 1056 bp)。结果分离株与参考株外膜蛋白的ORF存在6个碱基的缺失,蛋白质序列有变化。     

猪源多杀性巴氏杆菌ompH基因的克隆、表达

利用已分离的菌株030224HB，根据NCBI上的序列(U52208)设计了一对引物，用PCR方法扩增了猪源多杀性巴氏杆菌的外膜蛋白基因(ompH)，扩增的片段大小为1114bp(ORF为960bp)，并克隆到载体pMD18-T(T-Vector)，测序表明该基因相当保守。用pET-28b构建了原核表达载体pET28b-ompH，转化BL21并诱导表达，SDS-PAGE结果显示表达蛋白约为35ku，与报道大小相近。Western-blot结果表明表达的蛋白质具有生物学活性，然后用所表达的蛋白做了ELISA检测方法的初步探讨。     

禽源多杀性巴氏杆菌ompH基因序列分析

根据NCBI登录的序列(PMU50907)合成1对引物,用PCR方法扩增了郎德鹅多杀性巴氏杆菌ompH基因,预计扩增片段大小为1544 bp（ORF 1062 bp）,但是分离菌实际测序片段大小为1537 bp（ORF 1056 bp）。结果分离株与参考株外膜蛋白的ORF存在6个碱基的缺失,蛋白质序列有变化。     

牦牛源多杀性巴氏杆菌血清型鉴定及ompH基因序列分析

为分析牦牛多杀性巴氏杆菌(P.multocida)分离株与疫苗株的血清型和ompH基因差异,本研究利用PCR方法鉴定其血清型,并克隆、测序ompH全长基因,用DNAMAN、DNAStar对其进行生物信息学分析.结果显示,分离株与疫苗株血清型为B型,标准株血清型为E型.分离株和疫苗株ompH基因编码氨基酸有2个缺失和2个突变,同源性为99.4％.研究表明ompH基因具有很高的同源性,但氨基酸的缺失和突变可能使抗原表位发生变化,也是导致免疫失败的原因之一.     

不同动物源生产用多杀性巴氏杆菌外膜蛋白H基因序列分析

为了解国内不同动物源生产用多杀性巴氏杆菌外膜蛋白H基因的变异情况,采用PCR方法对16株不同动物源生产用多杀性巴氏杆菌的ompH基因进行扩增测序和分析。结果显示：16株菌株的ompH基因开放阅读框在1002～1056 bp之间;信号肽为N端20个氨基酸残基,成熟蛋白氨基酸残基数量在313～331 aa之间,氨基酸同源性为82.1%～100%;基于ompH氨基酸序列的系统发育树中鸡源菌株（荚膜A型）、猪源和牛源菌株（荚膜B型）分别在不同的分支。序列分析结果表明,ompH基因序列差异与荚膜型之间存在相关性,而与毒力大小无相关性。     

猪源多杀性巴氏杆菌荚膜分型及外膜蛋白H基因序列分析

为了解国内猪源多杀性巴氏杆菌外膜蛋白H基因的变异情况及与荚膜型之间的相关性,本试验采用PCR方法对44株猪源多杀性巴氏杆菌进行荚膜分型和ompH基因的扩增测序。结果显示,44株菌株中22株为荚膜A型,17株为荚膜B型,5株为荚膜D型;44株菌株的ompH基因开放阅读框在1 002~1 056bp之间;SignaIP 4.1预测结果显示,信号肽为N端20个氨基酸残基;ProtParam分析结果显示,成熟蛋白氨基酸残基数量在313~331aa之间,推测的分子质量在33.83~36.46ku之间。序列分析结果显示,44株菌株核苷酸同源性为86.2%~100.0%,氨基酸同源性为86.0%~100.0%;ompH基因核苷酸序列遗传进化树结果显示,荚膜A型、B型和D型菌株分别在不同的分支。试验结果表明,猪源多杀性巴氏杆菌ompH基因在不同血清型之间具有较高的同源性,与荚膜型之间存在相关性。     

不同牛源多杀性巴氏杆菌HasR基因的克隆及序列分析

为了克隆从患肺炎犊牛和健康犊牛上分离的多杀性巴氏杆菌血红素结合受体(heme acquisition system receptor,HasR)基因并进行序列分析,分别以致犊牛肺炎和健康犊牛携带的多杀性巴氏杆菌DNA为模板,通过PCR反应扩增出血红素结合受体基因的全部序列,PCR产物纯化后克隆到pMD19-T载体上,经菌液PCR和酶切鉴定后进行序列测定。各菌株HasR基因序列比对结果发现,Pm-BS-a、Pm142-x-4、Pm142-x-3、Pm149-x、Pm-BS-d的序列之间亲源关系较近,而Pm149-xby与参考菌株Pm70的同源性较高。健康牛源的多杀性巴氏杆菌与致犊牛肺炎多杀性巴氏杆菌之间HasR基因的同源性非常高,说明致犊牛肺炎多杀性巴氏杆菌是一种条件性致病菌,其引起的犊牛肺炎可能属内源性感染。     

羊源多杀性巴氏杆菌ompW基因的克隆及生物信息学分析

试验旨在克隆羊源多杀性巴氏杆菌ompW基因,并对其序列进行生物信息学分析。根据GenBank中多杀性巴氏杆菌HN07株ompW基因序列(登录号:CP007040.1),使用DNAMAN 5.0软件设计1对引物,选取高保真酶PrimeSTARMax DNA Polymerase进行PCR反应获取目的基因片段,并对ompW基因的核苷酸序列及预测的氨基酸序列进行生物信息学分析。结果表明,PCR扩增产物约为615bp,编码204个氨基酸。核苷酸同源性比对分析显示,羊源多杀性巴氏杆菌ompW基因与猪源、牛源、禽源多杀性巴氏杆菌同源性较高,而与兔源同源性较低。系统进化树结果发现,羊源多杀性巴氏杆菌ompW基因与猪源多杀性巴氏杆菌ompW基因亲缘关系最近。经生物信息学分析发现,ompW蛋白分子式为C1007H1567N257O283S3,分子质量为21.90ku,理论等电点(pI)为9.16,属碱性蛋白质,疏水指数为96.57,总平均疏水性(GRAVY)为0.173(>0),属于疏水类蛋白;前21位氨基酸为信号肽,第5-27位氨基酸区域存在1个跨膜区,存在N-糖基化位点及磷酸化位点,不存在O-糖基化位点,具有多个B细胞、CTL细胞及Th细胞抗原表位;二级结构的α-螺旋、延伸链、β-转角和无规则卷曲分别占17.65%、35.29%、3.92%和43.14%;三级结构是呈β-桶状的单聚体,隶属于外膜蛋白家族成员之一。本研究结果为进一步阐明羊源多杀性巴氏杆菌侵染宿主过程中自身的抗宿主免疫胁迫机制及疫苗的开发与研制提供了理论依据。     

禽源多杀性巴氏杆菌多位点序列分型研究

为了解国内禽源多杀性巴氏杆菌流行情况,对分离自18省份的84株多杀性巴氏杆菌采用荚膜多重PCR分型和多位点序列分型对其血清型和基因型进行鉴定。结果表明:禽源多杀性巴氏杆菌主要以血清A型为主,占96.4%(81/84);多位点序列分型可将禽源多杀性巴氏杆菌分为5种ST型,其中ST129为主要流行型,占94.0%(79/84)。本研究为我国禽源多杀性巴氏杆菌的流行病学监测和基因多样性提供了数据支持。     

羊源多杀性巴氏杆菌ompW基因的克隆及生物信息学分析

试验旨在克隆羊源多杀性巴氏杆菌ompW基因，并对其序列进行生物信息学分析。根据GenBank中多杀性巴氏杆菌HN07株ompW基因序列（登录号：CP007040.1），使用DNAMAN 5.0软件设计1对引物，选取高保真酶PrimeSTAR Max DNA Polymerase进行PCR反应获取目的基因片段，并对ompW基因的核苷酸序列及预测的氨基酸序列进行生物信息学分析。结果表明，PCR扩增产物约为615 bp，编码204个氨基酸。核苷酸同源性比对分析显示，羊源多杀性巴氏杆菌ompW基因与猪源、牛源、禽源多杀性巴氏杆菌同源性较高，而与兔源同源性较低。系统进化树结果发现，羊源多杀性巴氏杆菌ompW基因与猪源多杀性巴氏杆菌ompW基因亲缘关系最近。经生物信息学分析发现，ompW蛋白分子式为C₁₀₀₇H₁₅₆₇N₂₅₇O₂₈₃S₃，分子质量为21.90 ku，理论等电点（pI）为9.16，属碱性蛋白质，疏水指数为96.57，总平均疏水性（GRAVY）为0.173（> 0），属于疏水类蛋白；前21位氨基酸为信号肽，第5－27位氨基酸区域存在1个跨膜区，存在N-糖基化位点及磷酸化位点，不存在O-糖基化位点，具有多个B细胞、CTL细胞及Th细胞抗原表位；二级结构的α-螺旋、延伸链、β-转角和无规则卷曲分别占17.65%、35.29%、3.92%和43.14%；三级结构是呈β-桶状的单聚体，隶属于外膜蛋白家族成员之一。本研究结果为进一步阐明羊源多杀性巴氏杆菌侵染宿主过程中自身的抗宿主免疫胁迫机制及疫苗的开发与研制提供了理论依据。     

Characteristics of a haemolytic extract from avian Pasteurella multocida

In experimental fowl cholera, the intramuscular inoculation of Pasteurella multocida induces tissue damage that implies proteolytic or cytolytic activity of the bacteria. Such activity could not be demonstrated by conventional in vitro tests. The treatment of P. multocida strain VP21 with Tween-80 yielded an extract that lysed washed chicken red cells. Extracts were active to a maximum titre of 64. Haemolytic activity of the extract was neither affected by boiling nor by extremes of pH, indicating the active component was not a simple protein. Treatment with trypsin had no effect, but it was inactivated by Proteinase K. Yields were highest from bacteria grown in dextrose starch- or casein sucrose-yeast broths; were similar if cultured in air or anaerobically, but were reduced if the bacteria were grown in 5% CO(2). Haemolytic activity was eliminated on exposure to serum or serum albumen. The extract from strain VP21 haemolysed red cells from the chicken, rabbit, sheep, horse, bovine and human, with the highest titres observed on chicken cells. Six other avian strains and seven out of 10 strains of P. multocida from other species yielded an extract which haemolysed chicken red cells. The elaboration of this cytotoxic substance in vivo and its role in pathogenesis remains to be determined.     

Characterization of nine Pasteurella multocida isolates from avian cholera outbreaks in Indonesia

Avian cholera outbreaks have been identified in Indonesia in recent years. Despite vaccination programs, outbreaks continue to occur. To date, there has been a lack of information on the characteristics of Pasteurella multocida isolates involved in these outbreaks. Hence, the objective of this study was to characterize Indonesian P. multocida isolates in poultry. During 1998-99, 20 field outbreaks were reported in Indonesia. Nine isolates of P. multocida were recovered from these field outbreaks. The isolates were compared with four vaccine strains that were used in Indonesia and designated PM-V1, PM-V2, PM-V3, and PM-V4. The isolates were characterized by biotype, capsular type, somatic serotype, restriction endonuclease analysis, plasmid presence, and antimicrobial susceptibility patterns. Of the nine Indonesian isolates, three were of capsular type A (A:1,3,13; A:1,3; and A:8). One isolate was of type B:2,3 and one isolate was of capsular type F. For three isolates, the capsular serogroup could not be identified. Plasmids the size of 2.3 kbp were present in three of the field isolates and two of the vaccine strains. One plasmid less than 2 kbp was isolated from the vaccine strain PM-V4. Eight distinct DNA profiles were obtained from digestion with the restriction endonuclease EcoRI, and seven distinct DNA profiles were obtained from digestion with the restriction endonuclease HindIII. All of the isolates were resistant to lincomycin and sulfadiazine and were susceptible to ampicillin and trimethoprim. Of the nine isolates, seven (78%) were susceptible to doxycycline and gentamicin and six (67%) were susceptible to enrofloxacin.     

禽多杀性巴氏杆菌ompa DNA疫苗在小鼠体内免疫效果试验

应用PCR技术扩增获得禽多杀性巴氏杆菌的ompa基因片段,克隆到pUCm-T载体,再亚克隆到真核表达质粒载体pCDNA3.1(+)上,构建重组质粒pcA,体外转染Vero细胞,RT-PCR和间接免疫荧光试验检测其转录表达情况。动物免疫分为3组:pCDNA3.1(+)组、PBS对照组和pcA组,每组16只BALB/c小鼠,pCDNA3.1(+)组和pcA组以100μg/只的剂量肌注免疫,PBS组每只小鼠肌注100μL 1×PBS,各组均免疫3次,每次间隔2周。间接ELISA检测免疫后小鼠血清特异性抗体水平,MTT法检测免疫小鼠脾淋巴细胞增殖情况,三免2周后检测脾淋巴细胞IFN-γ分泌情况。强毒攻击,计算小鼠存活数目及保护率。结果显示,间接免疫荧光试验和RT-PCR检测结果均表明pcA可在体外培养的Vero细胞中表达目的蛋白。动物免疫后,pcA组免疫小鼠血清抗体水平持续上升,与pCDNA3.1(+)组和PBS组相比差异极为显著(P<0.01)。经提取的禽多杀性巴氏杆菌总外膜蛋白(Omps)刺激后,pcA组的刺激值(SI值)与pCDNA3.1(+)组及PBS免疫组相比均差异显著(P<0.05)。脾细胞产生的IFN-...     

Comparative sequence analysis of 16S rRNA gene of Pasteurella multocida serogroup B isolates from different animal species

The phylogenetic relationships of five isolates of Pasteurella multocida serotype B:2 belonging to buffalo, cattle, pig, sheep and goat were investigated by comparative sequence analysis of 16S rRNA gene. The 1468bp fragment of 16S rRNA gene sequence comparison showed that the isolates of cattle (PM75), pig (PM49) and sheep (PM82) shared 99.9% homology with the buffalo isolate (vaccine strain P52) whereas, the goat isolate (PM86) shared 99.8% homology with the vaccine strain. The 16S rRNA gene sequences of these isolates were also found monophyletic with type B reference strain NCTC 10323 of P. multocida subsp. multocida. The present study indicated the close relationships of haemorrhagic septicaemia causing P. multocida serotype B:2 isolates of buffalo and cattle with other uncommon hosts (pig, sheep and goat).     

A survey of potential virulence markers from avian strains of Pasteurella multocida

Twenty-four isolates of Pasteurella multocida from clinical cases of fowl cholera and the Clemson University vaccine strain were surveyed for the presence of potential virulence markers. Membrane proteins, enzymatic activity of the membrane proteins, and carbohydrate fermentation patterns were also determined to demonstrate phenotypic relationships within the groups. Few differences were found in these phenotypic characteristics among the isolates. Almost all the organisms produced siderophore and were hemolytic on turkey red blood cells. No extracellular enzyme or bacteriocin activity was detected and little antibiotic resistance was found. However, many organisms contained plasmids and demonstrated some degree of resistance to complement. Both characteristics were correlative markers in Pasteurella multocida isolated from birds with fowl cholera.     

Survival of avian strains of Pasteurella multocida in chicken serum

The ability of bacteria to survive in serum is considered a likely virulence determinant in diseases where the infective bacteria become septicaemic. Optimal conditions were established to test the survival of Pasteurella multocida in chicken serum. Serum was used at 90%, the inoculum was 10(3)-10(4)cfu in phosphate buffered saline pH 7.4. Survival was measured after incubation for 2-4 h; if survival was <50% the strain was considered serum susceptible. Susceptible strains were either killed or their growth was inhibited. Some resistant strains not only survived but grew rapidly in unheated serum. Thirty-five strains, all originally isolated from clinical fowl cholera, were tested; eight were susceptible, of which three were killed and five inhibited, and the remainder (27) were resistant. Ten serum-resistant P. multocida serogroup A strains were grown in hyaluronidase to remove the capsule and survival in chicken serum was re-tested. Three strains became susceptible, while seven strains remained resistant. Three serum susceptible strains were then tested in the presence of cytidine monophosphate-N-acetylneuraminic acid (CMP-NANA). This substance is present in the human serum, and is known to mask the effect of complement on Neisseria gonorrhoeae rendering susceptible strains resistant. Two of the three serum susceptible strains became resistant in the presence of CMP-NANA. Serum susceptibility/resistance was more complex than that of Escherichia coli, and the role of resistance to avian complement in the pathogenesis of fowl cholera remains to be determined.