葡萄皮渣原花青素酶法提取工艺优化及抗氧化性研究

以葡萄皮渣为试材,在单因素试验的基础上,采用L9(43)正交实验对葡萄皮渣原花青素的提取工艺进行了优化,并对纯化后的葡萄皮渣原花青素的抗氧化性进行了研究。结果表明:葡萄皮渣原花青素提取的最佳工艺参数为纤维素酶添加量0.4%,果胶酶添加量0.8%,酶解时间90min,酶解温度70℃。在此条件下,葡萄皮渣原花青素的得率为11.08mg·g-1。体外抗氧化试验结果表明,紫甘蓝原花青素表现出明显的抗氧化能力,对DPPH自由基和羟基自由基具有较好的清除能力,抗氧化能力优于维生素C。     

Stepwise in-straw dilution and direct transfer using open pulled straws (OPS) in the mouse: a potential model for field manipulation of vitrified embryos

In the present study, mouse blastocysts were employed to investigate the feasibility and efficiency of stepwise in-straw dilution and direct transfer using the open pulled straw (OPS) method. In experiment I, the effects of various vitrification solutions (VS) on embryo survival were examined. After thawing, the expanded blastocyst rates (97.59 and 95.05%) and hatching rates (80.48 and 78.95%) achieved in the EDFS30 [15% ethylene glycol (EG), 15% dimethyl sulfoxide (DMSO), Ficoll, and sucrose] and EFS40 [40% EG, Ficoll, and sucrose] groups were no different from those (96.15% and 83.33%) of the control group. However, the rates in the EFS30 [30% EG, Ficoll, and sucrose] (87.80 and 55.43%) and EDFS40 [20% EG, 20% DMSO, Ficoll, and sucrose] (95.69 and 70.97%) groups were significantly lower than those (96.15 and 83.33%) of the control group (P<0.05). In the experiment II, the effects of the volume of VS in the OPS on the survival of embryos after in-straw thawing were investigated. When the length of the VS in the column was less than 1 cm, the in vitro viability of embryos thawed by stepwise in-straw dilution was no different among the experimental and control groups. The embryos could be successfully thawed by immersing the OPS in 0.5 M sucrose for 3 min and then 0.25 M sucrose for 2 min. In experiment III, the effect of immersion time of the OPS in diluent (PBS) on the viability of vitrified embryos was investigated. After in-straw thawing, OPSs were immersed immediately in 1 ml PBS for 0 to 30 min. When the immersion time of the OPSs in PBS was less than 12 min, in vitro development of the in-straw thawed embryos was no different from that of the controls. In experiment IV, in-straw thawed blastocysts were directly transferred to pseudopregnant mice to examine their in vivo developmental viability. The pregnancy (91.67%) and birth rates (42.42%) of embryos in-straw thawed and directly transferred were no different from those of the unvitrified controls (90.90 and 40%) and embryos thawed by the conventional method (84.61 and 46.94%). These results demonstrate that mouse embryos vitrified with OPS could be successfully thawed by stepwise in-straw dilution and transferred directly to a recipient and that this method might be a model for field manipulation of vitrified embryos in farm animals.     

曲拉通和硝酸混合溶液直接提取快速测定草鱼中铅含量

为建立快速测定草鱼中铅含量的方法,通过分析曲拉通和硝酸混合溶液浓度、提取时间、称样定容体积比例等因素的影响,以及基体改进剂的使用效果,确定了草鱼中铅元素提取测定的最佳条件。验证结果显示：采用曲拉通和硝酸混合溶液提取草鱼中铅元素方法的提取率为86.5%～95.6%,加标回收率为91.5%～95.6%,精密度均小于4.0%,检出限和定量限分别为0.011和0.032 mg/kg,满足了国家标准GB 5009.12—2017第一法石墨炉原子吸收光谱法的要求。与国家标准方法比较,本研究建立方法的样品前处理时间从4～12 h缩短至0.2 h内,酸试剂用量从湿法消解的7～12 mL减少至1～2 mL;前处理过程无需高温消解,无需其他前处理设备,避免了样品污染和待测元素损失,实现了降低分析成本以及保护环境和试验人员的目的。结果表明,该方法是一种简单、准确、绿色、快速测定草鱼中铅含量的方法,尤其适合大量样品检测。     

猪源ST9型耐甲氧西林金黄色葡萄球菌中前噬菌体的流行状况与转导分析

本研究旨在分析猪源ST9型耐甲氧西林金黄色葡萄球菌(Staphylococcus aureus,MRSA)中前噬菌体的流行情况、结构特点和转导能力,探究前噬菌体在猪源MRSA流行克隆形成中的作用。基于全基因组信息,分析了近年来从我国多省分离的131株ST9型MRSA中前噬菌体的流行率、分型、亲缘关系和结构特征;选取含不同分型前噬菌体的菌株进行诱导,对诱导获得的噬菌体颗粒进行转导,测定转导子的耐药表型及体外适应性。研究结果显示：猪源ST9型MRSA的前噬菌体携带率为78.6%(103/131株),其中,63株携带完整前噬菌体序列,所有前噬菌体序列均不含耐药基因,仅2.9%(3/103株)的前噬菌体序列含毒力基因;前噬菌体谱型丰富,其整合酶分型主要为Sa2int和Sa4int;各型别前噬菌体结构同源性较高,完整前噬菌体可被诱导为长尾噬菌体;噬菌体颗粒可包装供体菌的aadD、tet(L)耐药基因并转导至受体菌中;转导子可获得卡那霉素、四环素耐药表型,体外生长能力与受体菌株无明显差异(P>0.05)。研究结果表明：猪源ST9型MRSA的前噬菌体携带率较高,谱型丰富,不携带耐药基因,部分噬菌体可包装供体菌的耐药基因转导至受体菌,产生的适应性代价小。     

微热光电系统燃烧室内截面突变对燃烧的影响

微燃烧室是微热光电（MTPV）系统的重要组成部分。微燃烧室的外表面必须产生一个高而均匀的温度分布，以尽可能高地输出辐射能。通过对截面突变的微燃烧室的试验研究，得到了不同氢氧混合气流量、氢氧体积混合比下燃烧室内的燃烧状况，壁面和出口端面的温度分布。试验结果表明：采用截面突变的燃烧室能很好地控制火焰中心位置，获得稳定的外壁面温度分布规律，可以在截面突变处产生涡流，增强氢气和氧气的混合。     

一体化微操作器误差分析与建模

为评价各种误差对微操作器精度的影响，以一体化超精密微操作器为研究对象，分析了加工误差、机构原理误差、测量误差、环境带来的误差以及驱动误差等造成微操作器精度降低的因素，建立了加工误差的偏微分方程解析模型，并用有限元仿真验证了加工误差模型的准确性。在详细分析误差源的基础上，提出了提高微操作器精度的措施。     

超声波对野生柴胡种子萌发及活力的影响

采用超声波对野生柴胡种子进行处理,测定种子的发芽势和发芽率以及种子的平均根长和简化活力指数.结果表明:经超声波处理25min,种子的发芽势和发芽率分别为13.33%、88.89%,比对照提高11.11%、44.45%;种子的简化活力指数为122.67,比对照高出98.23;处理时间在15～35min范围内,对种子的萌发以及种子的活力均有一定的促进作用.     

THE OPTIMAL DECISTON OF ECONOMICAL DEVELOPMENT BY MARKOVIAN DECISION PROGRAMMING

This paper studies the tactics choice and its improvement in the development of economy by means of Markovian Decision Programming. An optimal decision and the maximum expected revenue can be obtained. The . paper also presents the procedures and formulas of numerical evaluation.     

浅析中国种业的基本特征

本文从我国特殊的国情、特殊的消费群体、特殊的产品、特殊的产业四个方面揭示了中国种业的基本特征.