Toxoplasmosis in sheep. I. Effect of a killed vaccine on lambing losses caused by experimental challenge with Toxoplasma gondii

A total of 50 two-tooth ewes were immunized pre-tupping using a killed vaccine of disintegrated Toxoplasma tachyzoites with Freunds incomplete adjuvant. At mid-pregnancy, the ewes were challenged intravenously with 1 x 10(4) live T. gondii tachyzoites. There was no difference in the lambing percentage between ewes vaccinated once and unvaccinated ewes. The lambing percentage for ewes vaccinated twice was significantly lower (p<0.05 normal score) than unvaccinated ewes. The serological response to vaccination and challenge was measured by the Toxoplasma dye test. The level of dye test antibodies at the time of challenge suggests that effective immunity to Toxoplasma n abortion is not dependent on dye test antibody titre. These results suggest that a killed vaccine would Toxoplasma on fertility and lambing performance in not be an effective tool to estimate the effects of commercial flocks.     

Leptospira interrogans serovar hardjo associated with bovine abortion in South Africa

Leptospira interrogans serovar hardjo was isolated from urine from dairy cattle in the Onderstepoort area. This was the first successful isolation of this serovar as sole agent causing an abortion storm in the Republic of South Africa. Abortions occurred as early as at 4 months' gestation.     

Estimation of the proportion of inbred seed in Brussels sprouts hybrid seed by acid phosphate isoenzyme analysis

Summary The acid phosphatase isoenzyme patterns of extracts of seeds from Brassica oleracea subspecies and Brussels sprouts cultivars have been analysed. In view of the inhomogeneity of most seed material, the extracts must be prepared from single seeds if the patterns are to be used for taxonomic classification.The acid phosphatase isoenzymes located in the 15–20 mm region of the electropherograms proved to be controlled by one locus, which consists of 4 alleles acting without dominance. As a result, the acid phosphatase patterns of seeds of pure inbred lines are characterized by a single band in this region. Crossing of inbred lines with a different allele constitution gives hybrid seed with the related double-band pattern. No polypeptide hybridization occurs.By analysis of the acid phosphatase patterns of sufficient individual seeds in a seed sample from a new Brussels sprouts hybrid, it was possible to determine the proportion of inbred seed in the sample. The results were in good agreement with those obtained from field observations.     

Toxoplasmosis in sheep III. Further evaluation of the ability of a live Toxoplasma gondii vaccine to prevent lamb losses and reduce congenital infection following experimental oral challenge

The aim of this study was to compare the ability of a live incomplete strain (Strain 48) and a live complete strain (Strain 89) of Toxoplasma gondii to protect against abortion and congenital infection following an oral challenge of T. gondii oocysts. Sixty-nine two-tooth ewes were immunised pre-tupping with live Strain 48 of T. gondii tachyzoites and seventy ewes were immunised with Strain 89. Eighty-two serologically negative ewes served as controls. At mid-pregnancy half of the ewes were challenged orally with T. gondii oocysts (2x10(5)/ewe). The ewes vaccinated with Strain 48 were significantly (p<0.05) protected against the effects of experimental challenge and the rate of congenital infection was also significantly (p<0.15) reduced. The ewes vaccinated with Strain 89 were also significantly (p<0.05) protected. The serological response to challenge as measured by both the Dye test and the Indirect Haemagglutination test varied considerably between the two vaccinated groups.     

种茎对多花黄精产量和药用品质的影响

针对目前国内多花黄精种茎无标准和用种不规范的现状,研究多花黄精种茎规格、年龄对产量及药用品质的影响,旨在为多花黄精科学选种用种提供理论依据。采用双因素随机区组设计,主因素为规格,副因素为年龄,以多花黄精种茎的芽头数、茎长、茎径和茎质量为指标,采用K-means聚类法将种茎分成3个规格、3个年龄,通过调查出苗率、单株产量、单位面积产量和块茎多糖含量变化情况,分析不同规格、年龄种茎处理下2年生多花黄精产量和药用品质的差异。种茎规格、年龄与出苗率相关;种茎规格与单株产量、单位面积产量极显著相关,种茎年龄与单株产量、单位面积产量显著相关;种茎规格与多糖含量极显著相关,种茎年龄与多糖含量显著相关。推测种茎规格与年龄存在交互作用,高规格、低龄多花黄精种茎适宜作种,能显著提高多花黄精药材产量和药用品质。     

油库装车自动调节系统的改造

鄯善外运油库装车系统存在着一系列问题，例如球阀的开关控制与装车流量的调节不适应、装车管道出现憋地兰垫和收缩节受损等，针对上述问题先后对装车自动调节系统进行了三次技术改造，彻底解决了装车系统的超压问题，完全实现了装车系统自动调节控制。     

甜、糯玉米抗虫性的基因型差异

田间调查了不同基因型甜玉米和糯玉米的花叶率 ,螟虫、粘虫和棉铃虫数量以及后期植株上的虫孔数、幼虫数、单株虫道长和产量。结果表明 :花仙子和白雪丽人的受害程度较轻 ,黑妹和白糯的受害程度较重 ,花仙子的产量最高     

草地贪夜蛾V-ATPase亚基E、F、G和H基因的克隆与表达分析

【目的】液泡型ATP酶（vacuolar-type proton ATPase, V-ATP酶）维持着适合真核细胞内膜室生化功能的pH环境。本研究旨在克隆草地贪夜蛾Spodoptera frugiperda V-ATP酶V₁结构域E、F、G和H亚基基因,并对其时空表达谱进行分析。【方法】采用RT-PCR技术克隆了草地贪夜蛾V-ATP酶E、F、G和H亚基基因,通过实时荧光定量PCR技术测定了其在草地贪夜蛾不同发育阶段的表达动态。【结果】V₁结构域E、F、G和H亚基在鳞翅目昆虫之间具有高度保守性,且均与斜纹夜蛾Spodoptera litura同源性最高。E～H亚基在草地贪夜蛾所有发育时期均有表达,且都出现了在卵期和蛹期表达量低,雄成虫中高量表达的现象,同时不同的亚基在不同发育阶段表达量又有差异。【结论】本研究克隆了草地贪夜蛾V-ATP酶E、F、G和H亚基基因,明确了其在不同发育阶段的表达水平,为进一步研究基因功能以及筛选分子靶标奠定了基础。     

库鄯线减压站的控制

库尔勒—鄯善输油管道是我国第一条穿过大高差地段的常温密闭输送管道。大高差将会使管道高点不满流,造成液柱分离;停输时造成管道最低点超压。解决大高差给管道运行带来危害的方法是增大低点处管道壁厚或设置减压站。而减压站的关键设备是减压阀。正确选择性能优越、安全可靠的减压阀,制定合理稳妥的控制方案,是保障管道安全运行的关键。介绍了所选减压阀的技术性能、减压站的工艺流程、控制原理、控制程序及减压站上游压力设定值的计算。指出为将清管清出的又大又硬的蜡块破碎,在进站方向加一个碎蜡器,其效果尚待检验;管道最高点压力,只用于监视报警不参与控制;管道最低点既不参与监视报警,也不参与控制等,都是设计中存在的问题。