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61.
Atkinson RA Cook RW Reddacliff LA Rothwell J Broady KW Harper P Ellis JT 《Australian veterinary journal》2000,78(4):262-266
OBJECTIVE: To investigate the seroprevalence of Neospora caninum infection in a commercial dairy cattle herd, 15 months after detection of an abortion outbreak. PROCEDURE: Sera from the whole herd (n = 266) were examined for N caninum antibodies by indirect fluorescent antibody test (IFAT) and immunoblot analysis. Herd records were reviewed to collate serological results with abortion history, proximity to calving, and pedigree data. RESULTS: The seroprevalence of N caninum infection was 24% (63/266) for IFAT titre > or = 160, 29% (78/266) for immunoblot positive (+ve), and 31% (82/266) for IFAT > or = 160 and/or immunoblot +ve; 94% (59/63) of animals with IFAT > or = 160 were immunoblot +ve. The association between seropositivity (IFAT > or = 160 and/or immunoblot +ve) and history of abortion was highly significant (P < 0.001); the seroprevalence was 86% (18/21) in aborting cows, compared with 30% (50/164) in non-aborting animals. The abortion rate for seropositive cows was 26% (18/68) compared with 3% (3/117) for seronegative animals. IFAT titres of infected cows were higher within 2 months of calving than at other times (P < 0.001). The association between seropositivity in dams and daughters was highly significant (P = 0.009). CONCLUSIONS: The abortions were associated with N caninum infection and there was evidence of reactivation of latent infection close to calving and congenital transmission of infection. Immunodominant antigens identified by immunoblots may prove useful for improved diagnostic tests. 相似文献
62.
Suksawat J Hegarty BC Breitschwerdt EB 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2000,14(1):50-55
Ehrlichia canis, E. equi, and E. risticii seroprevalence was determined by microimmunofluorescent antibody testing (IFA) in a sequential population of 1,845 sick dogs admitted during a 1-year period to the North Carolina State University Veterinary Teaching Hospital. A seroreactor was defined by a reciprocal IFA titer of > or =80 to E. canis, E. equi, or E. risticii antigens. Of the 48 IFA seroreactors, 44 dogs were seroreactive to E. canis, 21 to E. equi, and 0 to E. risticii. Seventeen dogs reacted to both E. canis and E. equi antigens. There was concordance of E. canis IFA and western immunoblot (WI) test results for 36/44 dogs. Because of cross-reactivity of E. canis sera with E. equi antigens, WI was of less utility to confirm E. equi exposure. After elimination of E. canis seroreactors, there was concordance of 2/4 E. equi IFA and WI test results. Based upon a retrospective review of medical records, ehrlichiosis was diagnosed in 10/48 (21%) IFA seroreactive dogs, 9 of which were confirmed positive by WI. Of the remaining 38 IFA seroreactors, 29 also were confirmed by E. canis or E. equi WI. These results indicate that (1) ehrlichiosis was not diagnosed in the majority of serologically confirmed cases, (2) based upon E. canis and E. equi WI analysis, IFA testing was not specific (21% false positive), (3) E. canis sera cross-react with E. equi antigens, and (4) serologic evidence of E. risticii infection was lacking in the dog population studied. 相似文献
63.
将堆型艾美球虫(E.acervulina)3-1E基因克隆至pET-32a(+)载体中。转化大肠杆菌BL21,在37℃下,用终浓度为1.0mmol/L的IPTG诱导表达,得到相对分子质量约为38500的重组蛋白。Western blot检测证实,该重组蛋白可以与特异性抗血清结合。在20℃条件下,以终浓度分别为2.0、1.0、0.5mmol/L的IPTG进行诱导.当IPTG终浓度为0.5mmol/L时,以可溶性形式存在的目的蛋白含量最高。 相似文献
64.
地高辛标记cDNA探针检测苹果茎痘病毒 总被引:3,自引:0,他引:3
Partial sequence(314 bp) of ASPV was cloned and used as a probe labelled with digoxigenin-11dUTP. The total RNA extracted from samples with Apple stem pitting virus and a series of dilutions of plasmid with ASPV-cDNA were detected by dot blot hybridization. The results showed that the probe was sensitive and specific. The probe couldn't hybridize with total RNA of Apple stem grooving virus, Apple mosaic virus and Apple chlorotic leaf spot virus samples as well as negative control, only hybridized with that extracted from dormant shoot infected with ASPV. The sensitivity for detection of plasmid contained ASPV-cDNA was 1.64 μg. 相似文献
65.
西北牧区灌溉人工草地适宜发展规模分析 总被引:3,自引:0,他引:3
针对西北牧区水资源和草地资源已被超极限利用的现状,应用水草畜平衡原理,分析了西北牧区灌溉人工草地的发展规模,提出了西北牧区灌溉人工草地适宜发展规模为215.76~239.71万hm^2,载畜量控制在13833.18万羊单位之内即可实现草畜平衡,总体可达到人工种植冷季补饲水平。新增灌溉需水量约为71.85~83.55亿m^3,占2000年灌溉总用水量(777亿m^3)的9.25%~10.75%。解决这一灌溉需水量的可行途径是建设节水型社会,提高水资源利用效率。 相似文献
66.
为筛选与线虫感染性相关的基因,本研究以猪蛔虫为对象,构建猪蛔虫感染期幼虫差异表达消减cDNA文库,为研究线虫期特异性发育的分子机制奠定基础。分别提取感染期幼虫和其它各期幼虫及成虫的总RNA,纯化mRNA后,采用Clontech公司PCR-selectTM试剂盒进行反转录合成cDNA并进行抑制消减杂交(SSH),构建猪蛔虫感染期幼虫差异表达的消减cDNA文库,并采用Southern斑点杂交进行消减效率的检测。随机从文库中抽取45个克隆进行测序及在线BLAST分析。试验结果表明,感染期幼虫差异表达的消减cDNA文库具有较强的特异性;在得到的41个表达序列标签(ESTs)中,有40个ESTs与已报道的基因有较高的相似性,主要代表猪蛔虫第三期幼虫基因和成虫头部基因,有1个cDNA片段可能代表新基因。猪蛔虫感染期幼虫差异表达消减cDNA文库的成功构建,为进一步研究幼虫发育差异表达基因的功能奠定了基础。 相似文献
67.
68.
在对西部农村代课教师存在基础进行客观分析的前提下,提出解决西部农村代课教师问题的相关建议。 相似文献
69.
Abstract The smooth marron, Cherax cainii Austin, now occurs in regions of Western Australia that are warmer and drier than those of the natural distribution. Animals sourced along a south to north geographical axis decrease in body mass per unit length. Juveniles reared from gravid females sourced from four sites along this axis were raised in common laboratory conditions for 14 weeks. No differences between sites were observed in body mass, standardised for length, indicating that in situ differences are a phenotypic response to local conditions. 相似文献
70.