旋毛虫肌幼虫ES抗原的基因克隆及高效表达

作者对编码旋毛虫肌幼虫ES抗原的部分结构基因进行了克隆、鉴定和表达。用RNA PCR技术直接从旋毛虫肌幼虫总RNA中反转录并扩增出0．7kh的靶DNA,酶切分析后将其克隆到融合表达载体pEx3lC中。SDS—PAGE电泳表明,含重组子的大肠杆菌能够表达出一分子量为37kDa的融合蛋白(P37),后者占菌体总蛋白的22%以上,并以包含体形式存在于菌体中。经对纯化后表达蛋白的ELlSA检测,证明它能被猪旋毛虫病阳性血清和抗旋毛虫单克隆抗体识别。研究结果揭示,重组蛋白P37对于研制旋毛虫病诊断抗原和免疫抗原具有潜在的应用价值。     

Detection and Typing of Human Rotavirus in Reference to Repeated Acute Gastroenteritis in Infants

Stool specimens from infants who visited a clinic because of acute gastroenteritis were tested for the presence of human rotavirus. Among the samples obtained were specimens taken from seven patients who had visited the clinic at two different times. In six of these seven children, human rotavirus (HRV) was detected in only one of the specimens taken (i.e. during only one of the two visits). One patient was shown to have excreted HRV twice; in both cases the HRV was serotyped to be type 1. The present results indicate that the symptomatic reinfection of HRV was not a widely occurring phenomenon in the group of infants tested.     

杂交水稻及其“三系”线粒体DNA的AP—PCR指纹图谱

为了研究水稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．）细胞质雄性不育（ＣＭＳ）与线粒体基因组的关系,应用ＡＰ－ＰＣＲ 分析,用７ 个任意单引物对６ 种水稻品系线粒体ＤＮＡ 进行了扩增。水稻线粒体ＤＮＡ 的ＡＰ－ＰＣＲ 产物可分为三种类型：（１）所有供试品系均能扩增的片段,它们代表了线粒体ＤＮＡ 在进化上的保守性序列。有４ 个引物检测到这类片段。（２）２ 个以上水稻品系共同出现而在全部供试材料间存在差异的扩增片段,这类片段是检测水稻线粒体ＤＮＡ多态性的主要来源。（３）一种细胞质类型所特有的扩增片段,从引物Ｒ２ 和Ｖ５ 的扩增产物中发现了这类片段,它们可能与ＣＭＳ有关联。另外,ＷＡ型不育系珍汕９７Ａ 与其杂种之间在６ 个引物的扩增图谱上均存在不同程度的差异,说明两者的线粒体ＤＮＡ序列结构可能存在某种差别     

Detection of mycoplasma contaminations by the polymerase chain reaction

The polymerase chain reaction (PCR) has been used for the general detection ofMollicutes. 25Mycoplasma andAcholeplasma species were detected including important contaminants of cell cultures such asM. orale, M. arginini, M. hyorhinis, M. fermentans, A. laidlawii and additional human and animal mycoplasmas. PCR reactions were performed using a set of nested primers defined from conserved regions of the 16S rRNA gene. The detection limit was determined to be 1 fg mycoplasma DNA, which is equivalent to 1–2 genome copies of the 16S rRNA coding region. The identity of the amplification products was confirmed by agarose gel electrophoresis and restriction enzyme analysis. DNA from closely and distantly related micro-organisms did not give rise to specific amplification products. The method presented here offers a much more sensitive, specific and rapid assay for the detection of mycoplasmas than the existing ones.     

Guanine nucleotide regulatory protein alterations in young Milan hypertensive strain rats

Vascular smooth muscle cell membranes from prehypertensive rats of the Milan hypertensive strain (MHS) were used to examine adenylyl cyclase activity and its regulation by guanine nucleotide regulatory proteins (G-proteins). Basal adenylyl cyclase activity was similar in MHS and Milan normontensive strain (MNS) membranes. Forsokolin (10^?4 M) produced a significantly greater stimulatory response in MHS membranes, but this was not observed with NaF (10^?2 M). Isoporterenol (10^?4 M) caused a significantly decreased stimulation of adenylyl cyclase activity in MHS membranes, while prostaglandin E₁ (10^?5 M) produced similar responses in the two strains. G_i function and GTP responses, as observed by biphasic effects of GTP on isoproterenol-stimulated membranes, were similar in both strains. The levels of G_i2α and G_qα/G₁₁α were similar in the two strains, while the levels of G_sα (44 and 42 kDa forms) and the β-subunit were significantly reduced by ～20% in MHS membranes. The α-subunit of G_i3 was dramatically reduced by ～80% in MHS membranes. The affinities of β-adrenergic receptors for the antagonist, cyanophindolol, were similar in the two strains; however, the number of β-adrenoceptors was substantially reduced in MHS membranes. These findings may be of relevance to altered vascular reactivity and transmembrane ion distribution observed in the MHS.     

人脑髓鞘碱性蛋白cDNA体外扩增、克隆和鉴定

采用聚合酶链反应(PCR)从人脑cDNA文库中扩增出600bp的髓鞘碱性蛋白(MBP)cDNA片段,与载体pGEM-3Zf(+)平端连接.重组质粒DNA转化宿主菌JM109,在含X-gal和IPTG的平板上直接筛选阳性克隆.限制性内切酶分析和成套引物扩增鉴定证明,该克隆含有7个外显子的21.5kD人脑MBP全长编码序列.     

非同位素PCR－单链构象多态性技术的建立和应用

ＰＣＲ－单链构象多态性技术问世以来,成为研究基因突变的工具,特别是在分子肿瘤学研究中,广泛应用于癌基因,抑癌基因突变的研究,常规ＰＣＲ－ＳＳＣＰ采用同位素标记ＰＣＲ产物,测序板电泳分离突变,在操作和费用上有种种局限,文章建立了一种非同位素ＰＣＲ－ＳＳＣＰ技术;通过不对称ＰＣＲ获得单链,普通ＰＡＧＥ分离,经银染检出突变,用这种方法,还研究了四株鼻咽癌细胞株ＣＮＥ１,ＣＮＥ２,ＨＫ１和ＳＵＮＥ１中肿瘤     

The first decade of oligotrophication of Lake Constance

In Lake Constance, after several decades of cutrophication, a decrease in phosphorus loading over the last decade has lead to a partial recovery from eutrophication. Here we analyse the shift in the taxonomic composition of phytoplankton during the first decade of oligotrophication in Lake Constance. During the 1980s, spring total P concentrations decreased from ca. 130 to less than 50 ·l^–1. This decrease was reflected by an approximately proportional decrease in summer phytoplankton biomass while spring phytoplankton biomass seemed unresponsive. Major taxonomic changes occured during both growth seasons. In spring, the proportion of diatoms, green algae and Chrysophyta increased while the proportion of Cryptophyta decreased. The summer trend was very different: the relative importance of diatoms decreased and Cryptophyta and Chrysophyta increased, while Chlorophyta reached their peak around 1985. These trends are also analysed at the genus level. Comparison with taxonomic trends during the eutrophication period shows the expected reversals in most cases. Comparison with other lakes shows general similarities, with the notable exception that Planktothrix rubescens has never been important in Lake Constance. The increase of diatoms during spring is attributed to their improved competitive performance with increasing Si:P ratios. Their decrease during summer is explained by the increasing silicate removal from the epilimnion by increasing spring populations.