健康奶牛肠道中乳酸菌的分离与鉴定

在奶牛饲料中添加优良的乳酸菌微生物制剂对于生产实践有着重要的意义。由于奶牛肠道中的乳酸菌本身已适应奶牛肠道中的环境,并且与奶牛肠道中的致病菌长期拮抗竞争,因而是奶牛饲料中添加益生菌株的最佳来源。本试验利用改良MRS培养基从20头健康的荷斯坦泌乳牛粪便中进行菌群的分离鉴定,采用16S rRNA基因序列对分离的乳酸菌进行鉴定。最终获得瘤胃乳杆菌、乳酸乳球菌等18株乳酸菌。该试验中分离得到的乳酸菌为多角度开发我国乳酸菌资源和微生态制剂在畜牧生产中的应用奠定基础。     

豆科全基因组DGAT 基因家族的鉴定与进化分析

本文运用生物信息学方法在12个豆科植物基因组中对DGAT（甘油二酯酰基转移酶）基因进行了全基因组鉴定，发现在四倍体花生和大豆基因组中含有的基因拷贝数相对较多，分别为17、10，这可能是导致其油脂合成能力高于其他作物的重要因素。通过对家族基因进行系统发育分析，发现DGAT 基因在真双子叶植物分化之前已存在，在豆科植物中经历反复的全基因组加倍，使得家族得到扩张；并且串联重复对于家族扩增起到了不可忽视的作用，如葡萄中的两个旁系同源基因，由于串联重复使得基因拷贝数量提高了150%。大豆中DGAT 基因在不同的组织中表达模式与其系统发育关系也表现出了关联性。该基因家族相对保守，与豆科基因组进化基本保持了一致的进化速率。本研究对于认识豆科植物DGAT 基因进化过程具有重要的理论意义，同时在基因组学水平为大豆、花生等油脂合成品质改良提供了理论支撑。     

茶红素分离及稳定性研究

采用茶汤有机试剂萃取分离,并分别经过反相C_(18)柱层析纯化,制备出乙酸乙酯层、正丁醇层和酸性正丁醇层三部分茶红素。根据紫外可见光波扫描计算出色价,并研究了茶红素在不同条件下的稳定性。结果表明,30%、50%和70%甲醇梯度洗脱,纯化后3类茶红素液相检测发现无咖啡碱和茶黄素,仅有少量儿茶素杂质。纯化后色素色价分别为乙酸乙酯层128.04,正丁醇层91.04,酸性正丁醇层76.16。遮光处理,p H=3酸性条件,45℃以下贮藏,有利于茶红素的稳定性。     

Tagging quantitative trait loci for heading date and plant height in important breeding parents of rice (Oryza sativa)

Heading date and plant height are important determinants for plant growth rate. In this study, simple sequence repeat markers were used to tag quantitative trait loci (QTL) using a recombinant inbred line mapping population derived from two important breeding parents, genetic stock Kaybonnetlpa1-1 and indica cultivar Zhe733, using data collected under field and greenhouse conditions. Interval mapping, composite interval mapping, and multiple interval mapping were performed to map QTL for heading date and plant height, and to identify epistatic interactions between the QTL. qHD3.1 on chromosome 3 from KBNTlpa1-1 had the largest effect on heading date contributing an average of 28.4 % of the total phenotypic variation. qHD7.1, 7.2, and 8.1 also had a significant contribution to heading date from Zhe733 averaging 8.1, 12.8, and 12.8 % of the phenotypic variance, respectively, and there was a positive additive-by-additive epistatic interaction between qHD7.1 and qHD8.1. QTL, qPHT1.1 and qPHT3.1, for plant height were detected on chromosomes 1 and 3, respectively. qPHT1.1 contributed the largest effect representing 38.2 % of the total phenotypic variation. Comparison of the QTL identified in our study with previous results revealed that the chromosomal locations for QTL coincided closely with positions reported previously in other rice populations worldwide, suggesting that these QTL have coevolved and become domesticated. The tightly linked SSR markers that flank these QTL should be desirable for tagging heading date and plant height genes and facilitating their incorporation into advanced breeding lines using marker assisted selection.     

Acaricidal activity of extracts of neem (Azadirachta indica) oil against the larvae of the rabbit mite Sarcoptes scabiei var. cuniculi in vitro

The acaricidal activity of the petroleum ether extract, the chloroform extract and the acetic ether extract of neem (Azadirachta indica) oil against Sarcoptes scabiei var. cuniculi larvae was tested in vitro. A complementary log-log (CLL) model was used to analyze the data of the toxicity tests. The results showed that at all test time points, the petroleum ether extract demonstrated the highest activity against the larvae of S. scabiei var. cuniculi, while the activities of the chloroform extract and the acetic ether extract were similar. The activities of both the petroleum ether extract and the chloroform extract against the larvae showed the relation of time and concentration dependent. The median lethal concentration (LC(50)) of the petroleum ether extract (1.3muL/mL) was about three times that of the chloroform extract (4.1muL/mL) at 24h post-treatment. At the concentrations of 500.0muL/mL, the median lethal time (LT(50)) of the petroleum ether extract and the chloroform extract was 8.4 and 9.6h, respectively.     

Changes in peripheral blood leukocyte subpopulations in piglets co-infected experimentally with porcine reproductive and respiratory syndrome virus and porcine circovirus type 2

Porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) are pathogens, which can significantly affect the swine industry worldwide. Field surveys suggest that simultaneous PRRSV and PCV2 infection is common in pigs. The objective of this study was to measure the changes in peripheral blood leukocyte subpopulations in piglets co-infected experimentally with PRRSV and PCV2, in order to analyze the synergistic influence of co-infection on the immune system. Changes in peripheral blood leukocyte subpopulations were systematically measured by flow cytometry (FCM). The levels of antibodies to PRRSV and PCV2 were detected by indirect Enzyme-Linked ImmunoSorbent Assay (ELISA) and the indirect fluorescent antibody test (IFA), respectively. Serum viral loads were measured using real-time PCR. The results showed that piglets co-infected with PRRSV and PCV2 exhibited slower generation and lower levels of antibodies to PRRSV and PCV2, and increased amounts and a prolonged presence of both PRRSV and PCV2 in serum, in comparison to the piglets infected with either virus alone. The major finding in our study was that the total and differential leukocyte counts, including white blood cells (WBCs), monocytes, granulocytes and lymphocytes (T, B and NK cells, as well as T-cell subpopulations), dramatically decreased early during co-infection with PRRSV and PCV2 for about two weeks, in contrast with animals singly infected with either PRRSV or PCV2. These results suggest that PRRSV and PCV2 co-infection results in a synergistic decrease in immune cells in the peripheral blood of piglets. These data contribute to the understanding of the immunosuppressive effects resulting from PRRSV and PCV2 co-infection in pigs.     

引入陕西的天山马鹿产茸性能分析

对引入陕西的87头天山公马鹿的产茸资料进行统计分析。结果表明天山马鹿年平均产茸量5.56±1.98 kg。各锯龄平均产茸量由0.98±0.72 kg(1锯)到6.53±2.58 kg(10锯)不等。