共查询到20条相似文献，搜索用时 46 毫秒
1.
从患病华南虎分离病原菌,进行快速鉴定,同时以大肠杆菌16S rRNA基因的通用引物和irp2、papC、iucD、tsh、iss毒力基因的特异性引物进行PCR扩增、测序,并将扩增出来的irp2、iucD、iss基因序列与Genbank相应序列进行同源性分析。测序鉴定为大肠埃希氏菌,与传统细菌鉴定方法结果相一致,分离菌携带irp2、iucD、iss毒力基因,从毒力试验得到证实。其序列与Genbank上发表的iucD、iss基因序列同源性分别高达98%、99%,而irp2基因序列的同源性仅为48%。采用16S rRNA基因序列分析法可以对华南虎大肠埃希氏菌感染进行快速鉴定,华南虎源性大肠杆菌同时携带有irp2、iucD、iss 3个毒力基因,可能与其致病性有关系。 相似文献
2.
[Objective] The paper was to analyze the carrying status of high pathogenicity island(HPI) in pathogenic Escherichia coli of mink.[Method] Eight strains of E. coli were isolated from dead mink, and conducted pathogenicity test of artificial infection. The carrying status of HPI(irp2, fyu A) was detected by PCR. [Result] Eight strains of E. coli were pathogenic E. coli, and the carrying rate of HPI(irp2, fyu A) was 100%,positively correlated with the pathogenicity. [Conclusion] The results lay a foundation for further exploring the pathogenic mechanism of E. coli.. 相似文献
3.
4.
5.
腹泻水貂检出携带耶尔森菌HPI毒力岛的大肠杆菌 总被引：3，自引：0，他引：3
为了解大肠杆菌引起水貂腹泻的机理,进行了小肠结肠炎耶尔森菌HPI毒力岛基因的检测,并对其菌株做毒力试验。用PCR扩增法检测毒力岛基因irp2和fyua,小鼠腹腔注射检测菌株毒力。结果：从3个貂场腹泻病死水貂脏器以及粪便中分离出血清型分别为078、029和038的大肠杆菌,对3个血清型大肠杆菌进行毒力岛检测,均检出携带小肠结肠炎耶尔森菌HPI毒力岛基因irp2和fyua。3个血清型078、029和038的大肠杆菌均使小鼠发病死亡。结果表明水貂腹泻是由携带小肠结肠炎耶尔森茵HPI毒力岛基因irp2和fyua的大肠杆菌引起,该茵对水貂的健康具有潜在的威胁。 相似文献
6.
Live Pasteurella haemolytica biotype A, serotype 1 isolates (n = 3) and Escherichia coli K-12, strain W3110, were reacted with bovine pulmonary lavage cell (PLC) suspensions. The comparative effects of the different bacteria on the functional and metabolic activity of alveolar macrophages (AMO) in the PLC suspensions were assessed simultaneously by use of 51Cr release, luminol-dependent chemiluminescence (LDCL), and AMO bactericidal assays. The bovine PLC responded differently to E coli, than to the 3 P haemolytica isolates in each of the 3 experimental test systems; however, responses to each of the P haemolytica isolates were not found to be significantly different. Unopsonized live P haemolytica cells adversely affected the functional and metabolic response of PLC, whereas there was no evidence of a cytotoxic (cytocidal) influence of E coli. A difference in 51Cr release for reaction mixtures containing E coli and P haemolytica was not detected at zero time; however, at each subsequent time, reaction mixtures phagocytically stimulated with P haemolytica had significantly increased amount of 51Cr release (P less than 0.05), compared with those mixtures containing E coli. Bovine AMO in the PLC suspensions were able to effectively kill E coli in vitro, but were unable to prevent survival and subsequent growth of P haemolytica. The luminol-dependent chemiluminescence profiles for reaction mixtures phagocytically stimulated with E coli provided evidence of sustained production of oxygen radicals with antimicrobial capabilities by bovine AMO in the PLC. Production of these highly reactive antimicrobial oxidants appeared initially in cultures containing P haemolytica but, subsequently, their production declined precipitously and ceased altogether. 相似文献
7.
A luminol-dependent chemiluminescence (LDCL) assay was used to evaluate the response of bovine polymorphonuclear leukocytes; (neutrophils [PMN]) to living and heat-killed Escherichia coli, Pasteurella multocida (type A, serotype 3), and P haemolytica (biotype A, serotype 1), and to heat-killed P haemolytica and sterile culture supernatant from living P haemolytica. Control cultures containing PMN that had not been phagocytically stimulated with bacteria had a modest increase in LDCL during the initial 10 minutes of incubation, followed by a gradual decline throughout the 120-minute incubation period. Bovine PMN emitted LDCL more efficiently when the cells were exposed to living E coli or P multocida than when they were exposed to the same bacteria killed by heat. The mean LDCL values for reaction mixtures containing living E coli or P multocida peaked at 30 minutes of incubation and remained above values for mixtures containing the same heat-killed bacteria. Kinetics of the LDCL response of bovine PMN to heat-killed P haemolytica were similar (although reduced in amplitude) to that observed with killed E coli or P multocida. The LDCL response of bovine PMN to living P haemolytica was not like that for E coli or P multocida, and was characterized by the development of a peak response at 10 minutes followed by a precipitous decrease in responsiveness and a subsequent complete cessation of LDCL. Addition of sterile culture supernatant from living P haemolytica to test samples containing heat-killed P haemolytica induced a response similar to that obtained with the living microorganism.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
8.
Ten strains of adenovirus representing 10 serotypes were administered intratracheally to 3-week-old specific-pathogen-free chickens, which also received 2.9 X 10(5) colony-forming units of a pathogenic Escherichia coli intranasally. One group was given only E. coli, and one was retained as an uninoculated control. Gross pathologic alterations post-mortem were minimal and limited to multiple scattered, pale areas in the lungs of an occasional chicken in various groups. Histopathologic changes in the lungs were those of multifocal, interstitial, and occasionally diffuse pneumonia. Moderate to marked interstitial pneumonia was incited by adenovirus strains 75-1A, B-3 A-2, C-2B, and X-11; Ind-C, Stein, Tipton, J-2, and T-8 caused similar but milder lesions. Strains 75-1A, A-2, C-2B, T-8, and X-11 incited moderate to marked multifocal pneumonia; Ind-C, Stein, Tipton, J-2, and B-3 caused mild multifocal pneumonia. In all groups, the pneumonic lesions were more severe 5 days postinoculation than 12 days postinoculation. Bronchiolitis and tracheitis lesions also varied in severity with serotype. A mild hepatitis was seen with serotypes T-8 and 75-1A. Neither the uninoculated control group nor the group inoculated with only E. coli exhibited gross or histopathologic alterations. 相似文献
9.
对黑颈鹤病原菌进行快速鉴定及毒力因子分析。采用16S rRNA序列分析法鉴定黑颈鹤病原菌,其毒力基因分别用大肠杆菌的irp2、papC、iucD、tsh、iss毒力基因的特异性引物进行PCR检测,并将扩增出来的irp2基因序列与Genbank~（TM）相应序列进行同源性分析。分离菌株鉴定为大肠埃希氏菌,鉴定结果与生化检测结果一致,分离菌携带irp2毒力基因,这从毒力试验得到证实,其序列与与Genbank~（TM）上发表的HPI irp2基因序列同源性高达98%以上。采用16S rRNA序列分析法可以对黑颈鹤大肠埃希氏菌感染进行快速鉴定,黑颈鹤源性大肠杆菌携带有irp2毒力基因。 相似文献
10.
W J Foreyt 《American journal of veterinary research》1989,50(3):341-344
Six Rocky Mountain bighorn sheep were raised in captivity from birth (n = 5) or taken from the wild as a lamb (n = 1). After the bighorn sheep were in captivity for over a year, 6 clinically normal domestic sheep were placed on the 2 ha of pasture on which the bighorn sheep were kept. Nasal swab specimens were obtained from all sheep at the time the domestic sheep were introduced. Pasteurella haemolytica was isolated from swab specimens obtained from 4 of 6 domestic sheep, but not from specimens obtained from the bighorn sheep. All 6 bighorn sheep died of acute hemorrhagic pneumonia after exposure to domestic sheep. Death in the bighorn sheep occurred on days 4, 27, 27, 29, 36, or 71 after initial exposure to domestic sheep. Pasteurella haemolytica was isolated from respiratory tract tissue specimens of all bighorn sheep at the time of death. None of the domestic sheep were clinically ill during the study. At the end of the study, 3 of 6 domestic sheep were euthanatized, and at necropsy, P haemolytica was isolated from 2 of them. The most common serotypes in bighorn and domestic sheep were P haemolytica T-3 and A-2. Other serotypes isolated included P haemolytica A-1, A-9, and A-11 in bighorn sheep and A-1 in domestic sheep. On the basis of results of this study and of other reports, domestic sheep and bighorn sheep should not be managed in proximity to each other because of the potential fatal consequences in bighorn sheep. 相似文献
11.
A S Dhillon 《Avian diseases》1986,30(1):81-86
Ten strains of adenovirus representing 10 serotypes were administered intratracheally to 3-week-old specific-pathogen-free chickens, which also received 2.5 X 10(5) colony-forming units of a pathogenic Escherichia coli intranasally. Those birds had been inoculated by eye drop at 1 day of age with a virulent infectious bursal disease virus (IBDV). Controls consisted of groups of chickens inoculated with: (a) IBDV and E. coli, (b) IBDV only, (c) E. coli only, and (d) no virus or E. coli. Gross pulmonary alterations at 5 days postinoculation (PI) included congestion and consolidation of one or both lungs of a chick inoculated with adenovirus serotype Ind-C and another inoculated with A-2. Histopathologic alterations in the lungs were those of multifocal interstitial and occasionally diffuse pneumonia. All 10 adenovirus serotypes elicited multifocal or diffuse pneumonia and bronchiolitis in one or more of the five birds per group necropsied at 5 days PI. T-8 and A-2 serotypes induced marked to serve diffuse pneumonia within 5 days; Ind-C, Stein, Tipton, 75-1A, B-3, and X-11 incited a mild diffuse pneumonia. In all groups, the pneumonic lesions were more severe 5 days PI than 12 days PI. Tracheitis was incited by Ind-C, Stein, T-8, and A-2 at 5 days PI; the lesions were minimal to marked in severity. None of the four control groups exhibited gross or histopathologic alterations except the two IBDV-infected groups, which exhibited bursal change. 相似文献
12.
13.
从家蚕丝腺组织克隆得到2种mRNA形式的家蚕Bm eIF5A基因(GenBank登陆号:DQ202521;DQ201182),虽都具有相同的编码160个氨基酸的编码区,但却为不同长短的3′非编码区(3′UTR)。家蚕Bm eIF5A基因包含3个外显子和2个内含子。组织表达谱分析发现该基因在丝腺组织里高丰度表达。分析推导的氨基酸序列揭示该基因产物具有eIF5A家族蛋白质共有的保守区。序列同源性分析表明eIF5A家族基因在所有的真核生物中都高度保守。进化生物学的分析显示家蚕的eIF5A基因与昆虫的同源性较高。 相似文献
14.
Rapid detection of virulence-associated genes in avian pathogenic Escherichia coli by multiplex polymerase chain reaction 总被引：2，自引：0，他引：2
Based on recently published prevalence data of virulence-associated factors in avian pathogenic Escherichia coli (APEC) and their roles in the pathogenesis of colibacillosis, we developed a multiplex polymerase chain reaction (PCR) as a molecular tool supplementing current diagnostic schemes that mainly rely on serological examination of strains isolated from diseased birds. Multiple isolates of E. coli from clinical cases of colibacillosis known to possess different combinations of eight genes were used as sources of template DNA to develop the multiplex PCR protocol, targeting genes for P-fimbriae (papC), aerobactin (iucD), iron-repressible protein (irp2), temperature-sensitive hemagglutinin (tsh), vacuolating autotransporter toxin (vat), enteroaggregative toxin (astA), increased serum survival protein (iss), and colicin V plasmid operon genes (cva/cvi). In order to verify the usefulness of this diagnostic tool, E. coli strains isolated from fecal samples of clinically healthy chickens were also included in this study, as were uropathogenic (UPEC), necrotoxigenic, and diarrhegenic E. coli strains. The application of the multiplex PCR protocol to 14 E. coli strains isolated from septicemic poultry showed that these strains harbored four to eight of the genes mentioned above. In contrast, those isolates that have been shown to be nonpathogenic for 5-wk-old chickens possessed either none or, at most, three of these genes. We found only one enterohemorrhagic (EHEC), one enteropathogenic (EPEC), and two enterotoxic (ETEC) E. coli strains positive for irp2, and another two ETEC strains positive for astA. As expected, UPEC isolates yielded different combinations of the genes iss, papC, iucD, irp2, and a sequence similar to vat. However, neither the colicin V operon genes cva/cvi nor tsh were amplified in UPEC isolates. The multiplex PCR results were compared with those obtained by DNA-DNA-hybridization analyses to validate the specificity of oligonucleotide primers, and the protocol was concluded to be a useful, sensitive, and rapid assay system to detect avian pathogenic E. coli and differentiate them from nonpathogenic strains and those belonging to other pathotypes. 相似文献
15.
Nishimura Y Miyazawa T Ikeda Y Izumiya Y Nakamura K Sato E Mikami T Takahashi E 《Veterinary immunology and immunopathology》2000,73(3-4):353-359
We amplified the cDNA encoding the feline FcgammaRIIIA (CD16) homologue from peripheral blood mononuclear cells by polymerase chain reaction and cloned two forms of FCGR3A cDNA. Sequencing analysis revealed that the open reading frame of feline FCGR3A cDNA consists of 750 or 747 base pairs encoding 250 or 249 amino acid residues, respectively. Comparison of the predicted amino acid sequence of feline FCGR3A cDNA with those of other mammalians' homologues revealed that the extracellular domain has a relatively low homology. However, the cytoplasmic domain contained an 8-amino acid motif, Leu-Phe-Val-Val-Asp-Thr-Gly-Leu, which was considered to interact with an accessory molecule such as the gamma chain of Fc receptors for IgE to form heterodimeric complexes. 相似文献
16.
A 24-kDa cloned zinc metalloprotease from Actinobacillus pleuropneumoniae is common to all serotypes and cleaves actin in vitro. 
下载免费PDF全文
下载免费PDF全文 C García-Cuéllar C Monta?ez V Tenorio J Reyes-Esparza M J Durán E Negrete A Guerrero M de la Garza 《Canadian journal of veterinary research》2000,64(2):88-95
Actinobacillus pleuropneumoniae causes pleuropneumonia in swine. This bacterium secretes proteases that degrade porcine hemoglobin and IgA in vitro. To further characterize A. pleuropneumoniae proteases, we constructed a genomic library expressed in Escherichia coli DH5alpha, and selected a clone that showed proteolytic activity. The recombinant plasmid carries an 800-base pair A. pleuropneumoniae gene sequence that.codes for a 24-kDa polypeptide. A 350-base pair PstI fragment from the sequence hybridized at high stringency with DNA from 12 serotypes of A. pleuropneumoniae, but not with DNA from Actinobacillus suis, Haemophilus parasuis, Pasteurella haemolytica, Pasteurella multocida A or D, or E. coli DH5alpha, thus showing specificity for A. pleuropneumoniae. The expressed polypeptide was recognized as an antigen by convalescent-phase pig sera. Furthermore, a polyclonal antiserum developed against the purified polypeptide recognized an A. pleuropneumoniae oligomeric protein in both crude-extract and cell-free culture media. This recombinant polypeptide cleaved azocoll, gelatin, and actin. Inhibition of the proteolytic activity by diethylpyrocarbonate suggests that this polypeptide is a zinc metalloprotease. 相似文献
17.
Pasteurella haemolytica biotype A serotype 1 is the principal etiologic agent of bovine pneumonic pasteurellosis. A clear understanding of the pathogenesis of this disease and the mechanisms of resistance to it has been limited by a lack of information on the important antigens of the organisms. Using recombinant DNA techniques we have cloned a segment of DNA from P. haemolytica A1 that encodes three proteins of 28, 30, and 32 kDa. Two of these proteins, 30 and 28 kDa, react strongly on a Western blot with a bovine serum raised against live cells of P. haemolytica A1. The gene for the 30 kDa protein was localized to a 3.1 kbp EcoRI fragment, and expression of the 30 kDa protein was found to be independent of an E. coli promoter. The 30 kDa protein comigrated with a 30 kDa P. haemolytica protein that was susceptible to radioiodination and presumably exposed on the bacterial cell surface. The other principal radiolabeled P. haemolytica proteins were 100, 45, and 15 kDa. Antibodies against the 30 kDa protein, isolated from E. coli carrying the recombinant plasmid, recognized 30 kDa and 15 kDa proteins in P. haemolytica serotypes 1-15 and caused agglutination of whole P. haemolytica A1 cells. Cattle vaccinated with live P. haemolytica, P. haemolytica outer membrane proteins, or the cloned 30 kDa protein developed antibodies to the cloned 30 kDa protein as detected by Western blotting and densitometry. Sera were obtained from cattle vaccinated with live or killed P. haemolytica or saline and challenged with P. haemolytica. Those sera were evaluated for antibody responses to the cloned 30 kDa protein. High antibody responses to the 30 kDa protein significantly correlated (P less than 0.01) with resistance to challenge. From these studies it is concluded that the 30 kDa protein represents a surface antigen of P. haemolytica A1 that may be important in inducing immunity to P. haemolytica. 相似文献
18.
猪戊型肝炎病毒ORF2蛋白N端主要抗原表位区的原核表达 总被引：1，自引：1，他引：0
用原核表达系统表达猪戊型肝炎病毒ORF2蛋白N端的主要抗原表位区。通过对GenBank公布的猪戊型肝炎病毒DQ1株ORF2的氨基酸序列进行分析,确定了其N端抗原性较高的区域,针对此区域设计并合成了1对特异性引物,RT-PCR扩增该区段,并将此片段克隆到原核表达载体pET30a(+)上,命名为pET30a-ORF2N,转化大肠杆菌BL21感受态细胞,1.0 mmol/LIPTG37℃诱导表达。RT-PCR扩增得到424 bp的片段,重组蛋白大小约为21.8 ku,与预期大小相符。West-ern blotting分析结果表明,该蛋白能与阳性血清发生特异性反应,证明该蛋白具有生物学活性。猪戊型肝炎病毒ORF2蛋白N端主要抗原表位区在大肠杆菌中成功表达,具有一定的反应原性,为进一步用其建立诊断方法奠定基础。 相似文献
19.
猪戊型肝炎病毒ORF2蛋白C端主要抗原表位区的原核表达 总被引：1，自引：0，他引：1
利用分子生物学软件分析GenBank公布的猪戊型肝炎病毒DQ1株ORF2的氨基酸序列,确定了其C端抗原性较高的区域,针对此区域设计并合成了一对特异性引物,RT-PCR扩增该区域,并将此片段克隆到原核表达载体pET30a(+)上,命名为pET30a-ORF2C,然后转化大肠埃希菌BL21感受态细胞,1.0 mmol/L IPTG 37℃诱导表达。结果表明,RT-PCR扩增得到301 bp的片段,重组蛋白大小约为18 ku,与预期大小相符。Western blot分析表明,该蛋白与阳性血清发生特异性反应,为进一步利用其建立诊断方法奠定了基础。 相似文献
20.
Resistance to trimethoprim and 2,4-diamino-6,7-diisopropyl-pteridine (0/129) in Pasteurella haemolytica 总被引：1，自引：0，他引：1
Thirteen strains of Pasteurella haemolytica resistant to moderate levels of trimethoprim (MICs from 8 to 64 micrograms/ml) and 0/129 (MICs from 16 to 64 micrograms/ml) were isolated from bovine specimens. Two strains, CNP330 and CNP334, were studied and found to harbour various plasmids but all attempts to cure trimethoprim resistance were unsuccessful. Resistance characters were not transferable to Escherichia coli or to Pasteurella multocida by conjugation and to E. coli by transformation. The resistance gene(s) was therefore tentatively assigned to a chromosomal location and cloned into E. coli where it conferred trimethoprim resistance. Trans-complementation analysis of a dihydrofolate reductase-deficient mutant of E. coli showed that trimethoprim resistance was secondary to synthesis of a dihydrofolate reductase. DNA/DNA hybridization of the hybrid plasmid and of strains CNP330 and CNP334 with probes specific for dihydrofolate reductase types I to V were negative, indicating that cross-resistance to trimethoprim and 0/129 in P. haemolytica was due to the acquisition by P. haemolytica of a new resistance determinant. 相似文献