重组逆转录病毒载体的包装   总被引：1，自引：1，他引：0  

王凤阳  扈荣良  张茂林  赵君  涂长春  殷震 《中国兽医学报》2001,21(2):128-130

将3.7kb的LacZ基因片段克隆到含标志基因Neo的逆转录病毒载体，pLXSN与pLNCX的多克隆位点，构建了含有LacZ基因的重组逆转录病毒载体pLLSN和pLNCL.在测定了G418对饥装细胞系PA317的最小致剂量后（最小致死剂量为0.3g/L），通过脂质体Lipofectin与磷酸钙2种介质，分别将2种重组逆转录病毒载体导入包装细胞系PA317进行包装，并以0.3g/L，的G418进行筛选，得到多个G418抗性克隆，经扩大培养，传代，分别得到包装pLLSN与pLNCL的2株阳性细胞，电镜下可见阳性细胞的培养上清中具有逆转录病毒形态特征的成熟病毒粒子，本0研究为运用逆转录病毒载体系统，解决转角因效率低的问题奠定了基础。  相似文献   

巨峰葡萄晚秋叶施^15N—尿素的吸收,运转,贮藏和再分配   总被引：20，自引：2，他引：18  

管长志  曾骧S 《园艺学报》1993,20(3):237-242

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陕西秦巴山区的野生果树种质资源   总被引：3，自引：0，他引：3  

张亮成  罗耀祖 《园艺学报》1993,20(1):27-32

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TheEstimationofStemTaperCurvefromtheRadialInformationatThreeLocationsontheStem     

Zheng Xiaoxian Liu Donglan College of Forest Resources  Environment  Beijing Forestry University  Beijing  P.R.China 《中国林学(英文版)》1996,(1)

该文探讨了不用编制削度表直接建立高精度立木干曲线的方法．当采用干曲线是３次多项式时，通常根据１０分法测定树干各部位直径，用最小二乘法求出该方程式的参数．从数学角度，只要知道树干任意３个部位的直径，就可以用最小二乘法或联立方程式求解干曲线参数．本文以樟子松为例，探讨用树干哪３个部位直径拟合的干曲线最接近实际干曲线，为建立立木干曲线提供有效方法．利用９个部位半径（方法Ⅰ）和利用其中３个部位半径（方法Ⅱ，２８种组合）分别拟合干曲线，结果表明方法Ⅱ的６种半径组合的精度良好，其中的３种组合，（ｒ１．３，ｒ０．３，ｒ０．７），（ｒ１．３，ｒ０．４，ｒ０．７）和（ｒ１．３，ｒ０．４，ｒ０．８）是拟合现实干曲线的有效方法．  相似文献   

Lack of effect of recombinant bovine interferon alpha I1 in the treatment of experimentally-induced bovine warts.          下载免费PDF全文

M L Lassauzet  P A Salamin 《Canadian journal of veterinary research》1993,57(3):166-169

Fifteen four-month old calves were inoculated, on five scarified sites on each side of the neck, with a suspension of ground wart tissue from a steer naturally infected with bovine papilloma virus 1. Warts started to appear about one month postinfection and were measurable in ten calves two months postinfection, when the trial started. After stratification on the size of the warts, all fifteen calves were allocated randomly to one of the following treatment groups: twice weekly intramuscular injections of 5 mg recombinant bovine interferon alpha I1 (rBoIFN alpha I1), weekly injection of 5 mg of rBoIFN alpha I1 or placebo, for three weeks. The biggest wart on each calf at the beginning of the trial was measured and photographs of all warts were taken weekly for five weeks. An analysis of covariance on the log of the volumes of warts during the five weeks of the trial showed a significant difference between groups (p = 0.026). Warts in treated groups tended to grow faster than in the placebo group.  相似文献   

鸭梨秋施^15N尿素的吸收与分配   总被引：32，自引：2，他引：30  

徐季娥  陈良 《园艺学报》1993,20(2):145-149

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二十三个柚品种特性评价     

陈竹生  陈全友  江才伦  吴云伦  郭天池  聂华堂  计玉  甘俊新 《中国南方果树》1993,(2)

对1965年定植的23个柚(Citrus grandis Osbeck)品种进行了20多年的性状比较。筛选出矮化类型6个,早熟和晚熟类型各3个,丰产类型6个,品质优良类型11个。发现仅有部分柚品种富含维生素C;果汁中维生素C含量与酸含量呈明显负相关。证实长寿沙田柚中的冬瓜圈和古老钱两个选系比广西沙田柚更丰产优质;垫江白柚质优,但产量低。简述了各参试品种的利用前途。  相似文献   

Epidemiological study of enzootic pneumonia in dairy calves in Saskatchewan.   总被引：4，自引：0，他引：4       下载免费PDF全文

J Van Donkersgoed  C S Ribble  L G Boyer    H G Townsend 《Canadian journal of veterinary research》1993,57(4):247-254

A field study involving 325 calves from 17 dairy herds in Saskatchewan was conducted to determine the risk of enzootic pneumonia and to assess its association with a number of factors. Two different case definitions of pneumonia were used in the analyses: the first was based on producers' treatment risk (CASE1) and the second was based on semimonthly clinical examinations of calves by the research veterinarian (CASE2). The risk of pneumonia based on CASE1 was 39% and on CASE2 was 29%. The measure of agreement between CASE1 and CASE2 at the calf level of analysis was poor (kappa = 0.24, SE = 0.02) and at the herd level of analysis was moderate (kappa = 0.40, SE = 0.12). The mortality risk from pneumonia was 1.8% and a variety of infectious organisms were isolated from pneumonic lungs. Twenty-seven percent of the calves had inadequate (total IgG < or = 800 mg/dL) levels of passively acquired antibodies as measured by radial immunodiffusion. The proportion of seropositive titers in calves within the first two weeks of age was 94% to parainfluenza 3 virus (PI3V) and bovine respiratory syncytial virus (BRSV), 73% to Pasteurella haemolytica (Ph), 68% to bovine viral diarrhea virus (BVDV), 67% to infectious bovine rhinotracheitis virus (IBRV), 46% to Mycoplasma dispar (Md), 44% to Haemophilus somnus (Hs), and 21% to Mycoplasma bovis (Mb). At the calf level of analysis and after adjusting for clustering, there was a negative association (p = 0.10) between the diagnosis of pneumonia based on CASE2 and total IgG levels and Ph titers (rPh).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

柑桔授粉处理和单性结实子房（幼果）内源IAA,ABA和ZT含量的变化   总被引：44，自引：2，他引：42  

张上隆  刘春荣 《园艺学报》1994,21(2):117-123

广橙在授粉后３天内即完成受精，与未授粉子房相比，授粉子房迅速膨大，授粉处理可使内源ＩＡＡ、ＡＢＡ和ＺＴ水平急剧上升，尤其是在处理后的前３天。至第４天趋平缓。以每子房ｎｇ含量计，至处理后第３天，ＩＡＡ、ＡＢＡ和ＺＴ含量分别是处理开始时的６．８、５．２和４．１倍，而未授粉的分别为２．５、２．６和１．２倍，这种变化与子房（幼果）的发育密切相关。试验还分析了广橙授粉处理与内源激素平衡关系，发现授粉处理ＡＢ  相似文献   

中国野生种毛葡萄光合特性的研究   总被引：17，自引：1，他引：16  

朱林  温秀云  李文武 《园艺学报》1994,(1)

毛葡萄（ＶｉｔｉｓｑｕｉｎｑｕａｎｇｕｌａｒｉｓＲｅｈｄ）的净光合速率日变化值明显高于山葡萄、宝石、白玉霓，且无栽培品种光合作用的“午休”现象。毛葡萄的净光合速率与其它野生种葡萄和栽培品种比较也表现出较高水平。在进行ＣＯ２饱和点和补偿点测定时，毛葡萄也较栽培品种白玉霓有较强的光合作用，因此，毛葡萄是葡萄高光合效率育种的优良野生种质资源。  相似文献