大肠杆菌rpoH基因的克隆,表达及其产物的纯化

本文用ＰＣＲ方法获得大肠杆菌热休克蛋白转录因子σ３２的编码基因ｒｐｏＨ,并克隆在含有ｔａｃ启动子的表达载体ｐＵＨＥ中,经ＩＰＴＧ诱导,在大肠杆菌中表达了Ｃ端融合有６个寡聚组氨酸的σ３２。表达产物经金属螯合层析一步纯化,达到ＳＤＳ－ＰＡＧＥ银染一条带纯度,氨基酸组成分析及Ｎ端序列分析结果与文献报道一致。３５Ｓ细胞内参入实验表明：即使在较低的温度下,表达产物σ３２（Ｈｉｓ）６也能导致热休克蛋白如ＧｒｏＥｌ、ＤｎａＫ、Ｈｔｐ的大量合成．     

新疆血革螨属一新种（蜱螨亚纲：血革螨科）

本文报道血革螨属一新种,命名为狭背血革螨,新种Ｈａｅｍｏｇａｍａｓｕｓａｎｇｕｓｔｕｓｓｐ．ｎｏｖ．采自新疆乌苏,寄主为野兔。     

In vitro development of embryos from Sinclair miniature pigs: a preliminary report

The goal of this project was to identify conditions that result in development from the zygote or the 2-cell stage Sinclair miniature pig embryos to the blastocyst stage. Four media were selected, 2 that have been shown to result in in vitro development in domestic pigs (Hepes buffered Tyrode's medium and Whitten's medium), 1 that is compatible with similar development in the cow (CR-1), and 1 that is compatible with development in the mouse (CZB). One- and two-cell stage embryos from Sinclair miniature pigs were flushed from oviducts in Hepes buffered Tyrode's medium, allocated to 1 of the 4 media and cultured for 120 h. At the end of the culture period, embryos were morphologically scored and nuclei were counted. Morphology scores were lowest for Hepes buffered Tyrode's medium but were not different for Whitten's medium, CZB or CR-1. The highest (P < 0.07) number of nuclei was present in the oocytes cultured in Whitten's medium (21.3), with CR-1 (15.7) and CZB (16.5) not differing significantly. Similar to the morphology scores, Hepes buffered Tyrode's medium resulted in the lowest number nuclei (5.5). In a parallel experiment, domestic pig embryos were cultured in Hepes buffered Tyrode's medium versus Whitten's medium. The domestic pig embryos, while also developing better in Whitten's Medium, developed better in the Hepes buffered Tyrode's medium than did the embryos from Sinclair pigs. Thus, the Sinclair pig embryo develops best if placed in Whitten's Medium.     

龙血树真菌群及其对血竭形成的影响

从柬埔寨龙血树（Ｄｒａｃａｅｎａｃｏｃｈｉｎｃｈｉｎｅｎｓｉｓ）茎杆中分离到３０３株真菌,其中镰刀菌属（Ｆｕｓａｒｉｕｍ）菌株占总分离频率的５２％,其次是短梗霉（Ａｕｒｅｏｂａｓｉｄｉｕｍ）和枝孢霉（Ｃｌａｄｏｓｐｏｒｉｕｍ）。通过活体接种对血竭产生的影响试验表明,对血竭形成起重要作用的真菌主要是禾谷镰刀菌龙血树变种（Ｆ．ｇｒａｍｉｎｕｍｖａｒ．ｄｒａｃａｅｎａ）等４株红色镰刀菌,可使血竭形成量提高６６％－１２０％。     

甜玉米籽实含糖量的配合力分析

采用不完全双列杂交设计研究了 6个母本3个父本甜玉米自交系籽实含糖量的配合力效应。结果表明,父母本一般配合力和特殊配合力效应均方都显著。根据各亲本的表现把亲本5033归为一般配合力高而特殊配合力方差大的最理想类型;亲本5012和5011属一般配合力高而特殊配合力方差小的类型;亲本5018、5034、5028和5024为一般配合力低,但特殊配合力方差高的类型; 亲本5023和5009属一般配合力效应和特殊配合力方差都低的类型,最缺少实用价值。     

西藏厚厉螨属一新种和毛绥螨属一新种(蜱螨亚纲:厚厉螨科,裂胸螨科)

本文报道革螨二新种,西藏厚厉螨Pachylaelapsxizangensissp．nov．和亚东毛绥螨Lasioseiusyadongensissp．nov,1985年采自西藏亚东。     

雕盾螨属一新种记述（蜱螨亚纲：巨螯螨科）

本文记述雕盾螨属一新种;吴氏雕盾螨采自吉林省白城的土壤和马粪中。模式标本保存于全国鼠疫布氏菌病防治基地。     

氯喹导致大鼠肌组织载脂蛋白E大量表达

载脂蛋白E(ApoE)与迟发的家族性及孤发性阿尔茨海默(Alzheimer)病密切相关. 氯喹慢性中毒可诱发某些肌病理改变, 出现β淀粉样蛋白(βAP)与tau蛋白等的沉积, 与Alzheimer脑中见到的病理改变类似. 为分析这一改变的机制, 用逆转录结合多聚酶链反应技术(RT-PCR)对氯喹处理的大鼠肌肉中ApoE表达的改变进行了研究. 在PCR定量中采用了一种稳定表达的内源性甘油醛-3-磷酸脱氢酶mRNA作为内部参照. PCR扩增在很宽的循环数范围内成线性, 且靶mRNA与参照mRNA的扩增效率相当. 氯喹处理后大鼠肌肉中ApoE mRNA的表达从第6周开始增加, 第8周后超过对照组的20多倍. 结果提示, ApoE在氯喹慢性中毒所致的大鼠肌病理改变中发挥某些作用.     

枯草杆菌蛋白酶E的156和165位突变

应用定点突变方法,在M222A突变的枯草杆菌蛋白酶E基因上进行E156S和V165I定点突变. 将突变基因插入大肠杆菌-枯草杆菌穿梭质粒pBE-2中,在碱性和中性蛋白酶缺陷型的枯草杆菌DB104中进行表达,得到突变种(M222A,E156S)和(M222A,E156S,V165I)蛋白酶E. 性质测定表明,E156S突变使蛋白酶比活力增加90%,并不影响酶的热稳定性和抗氧化性. 而V165I突变使蛋白酶比活力降低.