足球场草坪运动质量影响因素的研究进展

综述了国内外足球场草坪运动质量影响因素的若干研究进展 ,并对当前我国足球场地草坪存在的问题进行了探讨     

引起笼养蛋鸡疲劳症的主要因素研究

本试验以营养因子、产蛋率、钙源、笼养生态等角度对笼养蛋鸡疲劳症进行综合研究,寻找引起笼养蛋鸡疲劳症的主要因素及减少笼养蛋鸡疲劳症的途径。     

Investigations on the Occurrence of Hereditary Diseases in the Danish Cattle Population 1989-1991

Agerholm, J.S., A. Basse and K. Christensen: Investigations on the occurrence of hereditary diseases in the Danish cattle population 1989-1991. Acta vet. scand. 1993, 34, 245-253.– The methods of the Danish Bovine Genetic Disease Programme are outlined, and the results obtained during the first 3 years in function are described. The most common disease reported was spinal muscular atrophy in calves of the Red Danish Dairy breed with 312 reports. Necropsy was performed on 162 cases, and spinal muscular atrophy was diagnosed in 82 of these. Bovine progressive degenerative mye-loencephalopathy, rectovaginal constriction, syndrome of arthrogryposis and palatoschisis, hereditary chondrodysplasia (2 different types), syndactylism, epitheliogenesis imperfecta, and osteogenesis imperfecta was diagnosed with 1 case each. Lethal trait A46 was diagnosed in 4 calves. Some of these diseases have not previously been described in Denmark, and epitheliogenesis imperfecta was for the first time diagnosed in the Hereford breed. Chromosome translocation 1/29 was detected in the Blonde d’Aquitaine (BAQ), Limousine, and Red Danish Dairy breed. The aberration occurred frequently in BAQ. Furthermore, a complex chromosome translocation t(l;8;9)(q45;ql3;q26) was detected in the Red Danish Dairy breed.     

乌鳢生长发育的生态因子及其流行病的防治

对非生物生态因子———水、光照、温度、溶氧、降水等和生物生态因子———食物、流行病和群体密度等对乌鳢生长发育的影响及流行病的防治进行了综述。     

Epidemiological studies of piglet diarrhoea in intensively managed Danish sow herds. II. Post-weaning diarrhoea

This study comprised 48,931 litters in 89 sow herds. During the study (1976-82) weaning age decreased from approx. 42 days to approx. 30 days. The mean incidence of post-weaning diarrhoea was 6.0% of litters weaned, with little variation by year but with considerable variation among herds. Within the individual herd increased incidence occurred over limited periods, probably associated with specific infections. Litters with diarrhoea during the suckling period had increased risk of post-weaning diarrhoea. The incidence of post-weaning diarrhoea increased with litter size at weaning. Thus, a litter of 11-12 piglets at weaning had 1.2 times higher risk than litters with 8-10 piglets. In contrast to pre-weaning diarrhoea, there was no association between parity of the sow and diarrhoea in the litter after weaning. Litters weaned below 2 weeks of age had a 2-fold risk of developing diarrhoea after weaning and a 2.4-fold higher mortality rate than did litters weaned at 6-7 weeks. Similarly, litters weaned at an individual piglet weight below 3 kg bodyweight had a 3-fold higher risk of developing diarrhoea after weaning and a 5-fold higher mortality rate than did pigs from litters weaned at a bodyweight of 7-8 kg. The incidence of post-weaning diarrhoea decreased with increasing herd size. Piglets from litters with post-weaning diarrhoea had reduced weight gains after weaning and were 2.3 days older at 25 kg bodyweight than piglets from non-diarrhoeic litters. Likewise, diarrhoea after weaning was associated with an increased incidence of diseases of the skin and respiratory tract. Thus the risk of contracting respiratory disease was 4 times greater in diarrhoeic litters.     

胆盐和游离脂肪酸影响离体小肠细胞类胡萝卜素吸收的研究

用黄鸡小肠细胞进行了 β-胡萝卜素和黄体素的体外吸收试验 ,研究类胡萝卜素浓度、胆盐和游离脂肪酸对这两种类胡萝卜素吸收的影响。结果发现 :β-胡萝卜素和黄体素的吸收均呈浓度依赖性 ;牛磺胆酸钠极显著促进黄鸡离体小肠细胞类胡萝卜素的吸收(P<0.01) ,其促进 β-胡萝卜素和黄体素吸收的最佳浓度分别为3mM和10mM ;游离脂肪酸极显著促进了类胡萝卜素的吸收(P<0.01) ,其中油酸对类胡萝卜素的促吸收作用大于硬脂酸 ,促进 β-胡萝卜素和黄体素吸收的最佳油酸/硬脂酸比率分别为100 :0和3 :1。牛磺胆酸钠和游离脂肪酸影响 β-胡萝卜素吸收的动态变化模式与它们对黄体素的显著不同     

水稻耐盐机理的研究Ⅲ.不同基因型对NaCl吸收和运转的动力学比较

本文应用动力学研究方法比较了具有不同耐盐性的3组共6个水稻基因型对NaCl吸收和运转的差异,结果表明,在外部低NaCl浓度(0.1mmolL~(-1)时,水稻对Na~+的吸收为被动吸收,耐盐基因型对Na~+的吸收速率显著低于盐敏感基因型;对Cl~-的吸收为主动吸收,不同耐盐性基因型吸收Cl~-的动力学参数(V_(?)、K_(?))差异不显著,在外部高NaCl浓度(50mmolL~(-1))时,耐盐基因型对Na~+和cl~-的吸收速率均低于对应的盐敏感基因型。耐盐基因型水稻的Na~+、cl-从根部向地上部的运转率低于对应的盐敏感基因型,这种差异在高盐浓度时更为明显。表明了耐盐基因型水稻地上部对NaCl的排斥作用是吸收控制和运转控制共同作用的结果,使地上部Na~+、Cl-含量相对降低而显出较高的耐盐性。     

影响老瓜头泌蜜量主导因素的研究

老瓜头自然分布于沙漠地带。在老瓜头开花期,天气变化无常。我们研究了对老瓜头泌蜜量起关键影响作用的气象因子。根据当地气候的变化规律进行预测预报,指导养蜂者正确选择场地,以夺取老瓜头蜜高产。     

大肠杆菌毒力因子研究概况

致病性大肠杆菌的毒力因子主要有黏附素、毒素、外膜蛋白 ( OMP)及铁转运系统等。在大肠杆菌侵袭宿主组织并引起其发病的过程中 ,这些毒力因子相互协调、发挥作用。文章对毒力因子的致病作用、致病机理、免疫原性及其在疾病防制中的应用几个方面的研究概况作了综述 ,为防制大肠杆菌病、研制新型高效的大肠杆菌疫苗提供了理论依据。另外 ,文章还介绍了近年来已相继研制成功的全菌体疫苗、纯化菌毛疫苗、单价或多价基因工程菌毛疫苗以及重组肠毒素双价基因工程苗、OMP亚单位疫苗等。展现了新型疫苗的研制 ,给防制大肠杆菌病带来了新的前景以及大肠杆菌作为工程菌的应用对畜禽其他疾病防制的推动作用     

黄瓜抗霜霉病异源易位系CT201的筛选与鉴定

 将栽培黄瓜‘北京截头’ (Cucumis sativus L. , 2n = 14) 与Cucum is属双二倍体新种C. hytivus (2n = 38) 回交, 随后自交。通过霜霉病田间接种试验筛选, 从中发现抗霜霉病单株HH12825。将HH12825与C. hytivus的原始亲本‘北京截头’和野生种C. hystrix进行农艺性状对比观察, 发现此单株在叶面积、节长、果长×果径等方面介于栽培黄瓜和野生种之间, 在侧枝数、果刺颜色等方面偏向野生种。观察其花粉母细胞减数分裂过程, 发现其PMC中期Ⅰ多价体频率(56% ±8% ) 和后期Ⅰ二价体分离滞后率(72% ±5% ) 都较高, 具有染色体易位的细胞学特征。进一步利用RAPD分子标记分析, 结果在40个随机引物中找到了两个引物( E219: ACGGCGTATG和A I220: CCTGTTCCCT) 能够在HH12825中重复地扩增出原始亲本野生种C. hystrix特异DNA片断, 从分子水平上证明了其为黄瓜异源易位系, 并把此易位系命名为CT201。