Pyrococcus sp.DNA聚合酶内蛋白子突变体的剪切性质

将含麦芽糖结合蛋白－嗜热菌ＤＮＡ聚合酶内蛋白子基因的ｐＭＩ８４、ｐＭＩ９４、ｐＭＩ９５三个重组突变体质粒转入Ｅ．ｃｏｌｉ２４２６经发酵及ＩＰＴＧ低温诱导表达,直链淀粉糖亲和纯化获得ＭＩ８４（ｓｅｒ１／Ｓｅｒ５３８Ｓｔｏｐ）、ＭＩ９４（Ｓｅｒ１→ＣｙｓＨ１／Ｓｅｒ５３８Ｓｔｏｐ）、ＭＩ９５（Ｓｅｒ１→Ａｌａ１／Ｓｅｒ５３８Ｓｔｏｐ）三种蛋白质前体。研究了ＰＨ温度、巯基试剂对内蛋白子Ｎ末端的剪切影响。     

酵母Mn—transporter基因研究进展

要酵母中有两个锰离子的转运系统：即高亲和力系统和低亲和力系统。本文简要介绍了酵母中与锰离子转运有关的基因：ＳＭＦ１、ＢＳＤ２、ＡＴＸ２、ＣＣＣ１、ＰＭＲ１和ＭＮＲ１及它们所编码蛋白的大小、细胞定位、跨膜域及他们在锰转运中的功能。文中不比较几中蛋白之间的关系。     

特种玉米栽培技术要点

特种玉米可分为两类：专用玉米和优质玉米。像甜玉米、糯玉米、爆裂玉米、青饲青贮玉米属于专用玉米，其用途单一，不能作它用；高油玉米、优质蛋白玉米属于优质玉米。特种玉米在栽培技术上要求比较严格，需要层层把关，否则当代所结的籽粒可能会失去特种玉米的性质，影响经济效益和社会效益。现将特种玉米栽培技术要点总结如下。     

PBNA： An Improved Probabilistic Biological Network Alignment Method

Biological network alignment is an important research topic in the field of bioinformatics. Nowadays almost every existing alignment method is designed to solve the deterministic biological network alignment problem.However, it is worth noting that interactions in biological networks, like many other processes in the biological realm,are probabilistic events. Therefore, more accurate and better results can be obtained if biological networks are characterized by probabilistic graphs. This probabilistic information, however, increases difficulties in analyzing networks and only few methods can handle the probabilistic information. Therefore, in this paper, an improved Probabilistic Biological Network Alignment（PBNA） is proposed. Based on Iso Rank, PBNA is able to use the probabilistic information. Furthermore, PBNA takes advantages of Contributor and Probability Generating Function（PGF） to improve the accuracy of node similarity value and reduce the computational complexity of random variables in similarity matrix. Experimental results on dataset of the Protein-Protein Interaction（PPI） networks provided by Todor demonstrate that PBNA can produce some alignment results that ignored by the deterministic methods, and produce more biologically meaningful alignment results than Iso Rank does in most of the cases based on the Gene Ontology Consistency（GOC） measure. Compared with Prob method, which is designed exactly to solve the probabilistic alignment problem, PBNA can obtain more biologically meaningful mappings in less time.     

二阶导数光谱法测定蛋白质的含量

导数光谱是紫外可见分光光度法中用以排除干扰的一种技术。本文用日立220—A紫外可见分光光度计中测定了血清蛋白质的含量。通过实验得出的线性回归方程为D=155.24c—0.346;相关系数r=0.9998,样本平均回收率为100.05％,精度试验d=0.077,S=0.418,dx=0.027,Sx=0.148。此法重现好,变异系数(CV)<±1％,此法简单,快速,可用于血清蛋白质的测定。     

植物多糖提取液的几种脱蛋白方法的比较分析

多糖对肿瘤、病毒、心血管等方面具有独特的生物活性,且细胞毒性很低,因此多糖的分离及纯化一直是一个很有意义的研究课题.实验以多糖损失率和脱蛋白率(r)为衡量指标,通过对几种脱蛋白方法的比较,优化出植物多糖提取液的脱蛋白方法,为多糖的纯化提供了一定的参考.选用了3种较为常见的方法:三氯乙酸法、盐酸法及沙维积法(Sevag 法)对植物多糖提取液进行脱蛋白处理.三氯乙酸法、盐酸法及Sevag法的脱蛋白率分别为46.1%、72.5%和42.3%,多糖损失率分别为6.1%、15.1%和14.3%.盐酸法脱蛋白率高,但它的多糖损失率较高;三氯乙酸法较温和,但除蛋白效率不高;Sevag法的脱蛋白效果不及前两种方法.     

东北枸杞多糖提取分离工艺优化

从单因素实验入手,用化学方法探讨了东北枸杞多糖的浸提条件,包括浸提固液比、浸提温度、浸提时间等因素,通过正交试验确定最佳浸提条件。实验结果表明:用热水浸提法,料水比1∶15,100℃水浴中浸提4 h,用95%的乙醇醇沉2 h,产率较高。用Sevag法除蛋白效果较好。     

安全使用电动农机具须知(下)

7.经常检查电动机轴承、定子、外壳等部位的温度. 使用过程中,要经常检查电动机的轴承、定子、外壳等部位的温度有无异常变化,尤其对无电压、电流和频率监视,没有过载保护的电动农机具,对其温度的监视更为重要.