气肿疽梭菌CctA基因的原核表达及其间接ELISA检测方法的建立

研究旨在原核表达气肿疽梭菌细胞毒素A （CctA）基因,用纯化的重组蛋白建立其间接ELISA检测方法,a。利用大肠杆菌密码子的偏爱性优化CctA基因序列,克隆至原核表达载体pET-28a （+）,双酶切鉴定原核表达质粒pET28a-CctA并测序。将重组质粒转入大肠杆菌,经IPTG诱导得到高表达的重组CctA包涵体蛋白。包涵体蛋白变性后经镍（Ni）柱纯化,SDS-PAGE检测其纯化效果。以豚鼠抗气肿疽梭菌抗血清为一抗,用Western blotting方法检测重组CctA蛋白的反应原性。用棋盘滴定法建立间接ELISA检测方法,以复性后的重组CctA蛋白作为检测抗原,摸索抗原包被浓度、封闭液的种类及浓度、抗体的最适稀释度和反应条件等。选用3批气肿疽灭活疫苗免疫豚鼠后采集血清,同时用攻毒和间接ELISA两种方法验证疫苗的免疫效力。质粒双酶切结果显示,得到大小约853 bp的条带,与预期相符,且测序结果正确。SDS-PAGE结果表明,成功表达并纯化大小为35 ku的重组CctA蛋白。Western blotting结果显示,豚鼠抗气肿疽梭菌抗血清与重组CctA蛋白具有良好的反应原性。建立的间接ELISA法的最适条件为：抗原的包被浓度为0.5 μg/mL,于4 ℃包被过夜;封闭液选择10%胎牛血清,37 ℃孵育2 h;二抗的稀释度为1：8 000;室温避光显色10 min后终止反应,测定D_{450 nm}值。当P/N>4.6时,间接ELISA法检测结果与豚鼠攻毒试验结果拟合度较好。本研究成功表达CctA基因并纯化了重组CctA蛋白,建立的以重组CctA蛋白为检测抗原的间接ELISA检测方法,有望成为气肿疽灭活疫苗免疫效果验证的替代方法。     

规模化养猪场疾病防控

养猪场以前饲养数量较少时采用传统的综合防控措施,如免疫接种、药物预防和治疗等,在疾病防控方面都起到关键作用且效果明显,但是随着饲养数量增加,只采用上述措施远远不够,应树立创新理念和生物安全措施,才能更有效的防控疾病发生。     

Effects of soybean raffinose on growth performance,digestibility,humoral immunity and intestinal morphology of growing pigs

There are appreciable does of raffinose in soybean, but the impacts of raffinose on pigs are poorly investigated. We used 2 experiments to investigate the influence of soybean raffinose on growth performance, digestibility, humoral immunity and intestinal morphology of growing pigs. In Exp. 1, a total of 30 crossbred (Duroc × Landrace × Yorkshire) barrows (21.93 ± 0.43 kg) were randomly divided into 3 groups, and were fed with the control diet, the control diets supplemented with 0.2% and 0.5% raffinose, respectively, for 21 d. Results showed that the addition of 0.2% or 0.5% raffinose reduced (P < 0.05) average daily feed intake (ADFI), average daily gain (ADG) and nutrient digestibility, and dietary 0.5% raffinose increased the ratio of feed to gain (P < 0.05). For serum indexes, dietary 0.5% raffinose decreased growth hormone and increased glucagon-like peptide-2, immunoglobulin G, tumor necrosis factor-α (TNF-α) and interleukin-6 concentration (P < 0.05). In Exp. 2, a total of 24 crossbred barrows (38.41 ± 0.45 kg) were randomly divided into 3 groups, and were fed with the control diet (ad libitum), the raffinose diet (0.5% raffinose, ad libitum), and the control diet in the same amount as the raffinose group (feed-pair group) for 14 d, respectively. Compared with the control diet, dietary 0.5% raffinose decreased ADFI (P < 0.05). Intriguingly, the raffinose group had lower ADG than the feed-pair group, lower nutrient digestibility, lower amylase activity in duodenum, lower amylase, lipase and trypsin activities in jejunum and higher TNF-α concentration in serum compared with the other 2 groups, and a higher ratio of villus height to crypt depth compared with the control group (P < 0.05). These results showed that soybean raffinose could reduce feed voluntary intake and body gain while improving intestinal morphology without a significant negative influence on immunity. Taken together, dietary raffinose could decrease growth performance by reducing both feed intake and nutrient digestibility while inducing humoral immune response of growing pigs.     

冬小麦种质“矮孟牛”中新型小麦-黑麦复杂易位的遗传传递分析

本文利用矮孟牛中一种新型小麦-黑麦复杂易位IRS·7DS,1BL·7DL与1BL·1RS易位所构建的一套重组自交系(包括109个F6株系)和8个矮孟牛衍生品种进行了分析,结果表明在109个F6株系中,纯合复杂易位占69个,纯合1BL·1RS占36个,二者比例约2∶1,杂合类型占4个,出现频率4/109;对矮孟牛8个衍生品种的分析表明,6个品种包含来自矮孟牛的     

多叶羽扇豆种子发芽条件的研究

在不同温度条件下,对多叶羽扇豆(Lupinus polyphyllus lindl)进行发芽试验,并利用不同药剂对多叶羽扇豆的硬实种子进行处理,得出以下结论:多叶羽扇豆发芽的最适温度在20℃左右,其发芽势计算应以前5 d发芽数为标准,其硬实种子采用浓硫酸处理2～5min发芽效果最好.     

灌溉设备产品信息与报价系统的开发

本文介绍了开发灌溉设备产品信息与报价系统的必要性及功能 ,较系统地阐述了该软件系统的实现思路 ,并对其应用前景作了初步预测     

旱涝交替胁迫对水稻产量和品质的影响

以"南粳44"为试材,采用温室盆栽试验,研究了分蘖期和拔节期旱涝交替胁迫对水稻产量和品质的影响。结果表明,分蘖期旱涝交替胁迫导致水稻的有效穗数较对照显著降低了20.0%和26.3%,拔节期旱涝交替胁迫导致水稻每穗粒数较对照显著降低了28.2%和41.1%,水稻产量均显著降低。分蘖期旱涝交替胁迫使稻米的出糙率、精米率和整精米率均下降,拔节期旱涝交替胁迫提高了稻米的整精米率,分别提高3.0%和2.4%,并显著降低了垩白率和垩白度。各胁迫处理均提高了稻米直链淀粉量,分蘖期重旱轻涝胁迫使得稻米的粗蛋白量较对照显著降低了7.6%。     

国内甘薯机械移栽技术发展动态

甘薯机械化移栽技术发展严重滞后已成为制约甘薯现代化生产的主要技术瓶颈。在对国内外甘薯机械移栽技术发展现状阐述、分析基础上,初步提出国内甘薯移栽机械的技术发展方向:农机农艺融合提高移栽效率、裸苗移栽优先、重视钵苗移栽、多种栽插形式并存、先栽后浇分段作业等。     

柴油/天然气双燃料发动机工作过程模拟计算

把柴油/天然气双燃料发动机工作过程分成七个阶段:压缩阶段、滞燃期阶段、燃烧阶段、纯排气阶段、进排气阶段、纯进气阶段,建立了每个阶段的数学模型,燃烧过程用三个Wiebe函数来描述。在Matlab下的Simulink环境中建立发动机工作过程的仿真模型进行模拟,将仿真数据与试验数据进行对比,发现该模型的仿真结果与试验数据相吻合。     

Research Progress on Action Mechanism of Animal Anti-parasitical Drugs

Animal anti-parasitical drugs are mainly used to prevent and control animal parasitosis, and also an effective way to protect the healthy development of animal husbandry and public health security.The efficacy of anti-parasitical drugs depends on the interaction between drug molecular and different target tissues and target cells of parasite or animal.Because of the variety of anti-parasitical drugs, the anti-parasitical mechanisms are complex.With the development of new anti-parasitical drugs and the depth of scientific research, especially the development of chemical synthesis and biological pharmaceutical technology, the variety and quantity of anti-parasitical drugs constantly increase.With the discovery of new drug structure and its action target, the study on the mechanism is constantly deep.The author mainly summarized the research progress on action mechanism of anti-parasitical drugs.