Bovine papillomavirus genome elicits skin tumours in transgenic mice

Transmission of the bovine papillomavirus-1 (BPV-1) genome through the mouse germ line results in the heritable formation of fibropapillomas of the skin, a tissue-specific phenotype analogous to that observed in natural BPV-1 infection of cattle. Oncogenesis is slow, with tumours first arising at 8-9 months of age, usually in areas prone to wounding. Extrachromosomal BPV-1 DNA is detected in all tumours, whereas normal tissues show only integrated DNA.     

Notch signals control the fate of immature progenitor cells in the intestine

The Notch signalling pathway plays a crucial role in specifying cellular fates in metazoan development by regulating communication between adjacent cells. Correlative studies suggested an involvement of Notch in intestinal development. Here, by modulating Notch activity in the mouse intestine, we directly implicate Notch signals in intestinal cell lineage specification. We also show that Notch activation is capable of amplifying the intestinal progenitor pool while inhibiting cell differentiation. We conclude that Notch activity is required for the maintenance of proliferating crypt cells in the intestinal epithelium.     

广东地区宫颈癌组织HPV18L1基因的克隆及序列分析

目的:了解广东地区地方株HFV18L1基因结构特点,为HPV感染的检测和基因工程疫苗的研制提供实验基础.方法:采用PCR技术从广东地区宫颈癌组织中扩增HPV18L1基因,克隆人毕赤酵母表达载体pPICZaB,测序并对HPV18L1基因进行序列分析.结果:广东地区分离株与德国标准株在核苷酸序列上有4处不同,其中3处由于核苷酸的改变,其编码的氨基酸也发生相应变化,与标准株的同源性为99.8%.与中国西安地区分离株比较有两处突变点相同.结论:广东地区HPV18L1分离株与德国标准株、中国其他地区分离株之间均存在差异.     

A novel type of human papillomavirus associated with genital neoplasias

The role of human papillomaviruses (HPVs) in the development of genital neoplasias has been well documented. The genomes of two HPV types, HPV16 and HPV18, have been found to be associated with about 70% of invasive carcinomas of the uterine cervix. As, under non-stringent hybridization conditions, HPV DNA sequences have been detected in about 90% of cervical carcinomas, it seems likely that additional HPV types are associated with these tumours. Here we report the molecular cloning and characterization of a novel HPV type, tentatively named HPV33, whose sequences have been detected in 4-8% of biopsies of genital intra-epithelial neoplasias and cervical invasive carcinomas, usually as free monomeric or oligomeric molecules. However, in one specimen of vulvar Bowen's disease, HPV33 DNA sequences were integrated in the host-cell genome. Thus, HPV33 probably represents an additional type of potentially oncogenic genital HPV.     

HIF-1调控小鼠bace1基因的转录表达

阿尔茨海默症的一个关键致病原因是大脑中淀粉样蛋白（A13）的过度产生或堆积．Aβ是由其前体蛋白APP经β-和γ-分泌酶依次水解而生成的，但对于这些分泌酶基因表达的转录调控的了解还很少．由于大脑发生缺氧／缺血会造成Aβ的产量增加，而缺氧时所激活的转录因子HIF-1（Hypoxia-Inducible Factor 1）会调控下游多种基因的表达，我们对HIF-1是否参与调控β-分泌酶的表达进行了研究．对小鼠β-分泌酶基因bace1的调控序列进行分析，发现其中含有一个缺氧应答元件（Hypoxia-Responsive Element，HRE）．我们的数据显示，HRE突变片段启动报告基因荧光素酶表达的活性比正常序列片段的启动活性明显降低．电泳迁移率的变动分析（EMSA）实验进一步证实，HIF-1可以与小鼠bace1中HRE元件相互作用．当在哺乳动物细胞中过度表达HIF-1时，BACE1的mRNA水平和蛋白质水平均有明显的增高．这些结果表明小鼠bace1基因的表达受转录因子HIF-1的调控．鉴于目前阿尔茨海默症研究领域都把抑制BACE1作为首选治疗靶位，HIF-1因而有可能成为治疗AD的一种药物靶点．     

OSP-1启动子在猪卵巢颗粒细胞中的转录活性研究

为获得能在猪卵巢颗粒细胞中高效表达的启动子,本文检测了大鼠卵巢特异性启动子OSP-1(Ovarian specific promoter)在猪卵巢颗粒细胞中的转录活性。参考大鼠OSP-1启动子序列扩增大鼠OSP-1片段,将其定向克隆到pc DNA3.1(+)中替代CMV启动子,并在其下游插入Zs GREEN基因片段,构建真核表达载体p OSP-1-Zs GREEN;重组质粒在脂质体LipofectamineTM2000的介导下转染不同细胞,在荧光显微镜下观察Zs GREEN表达情况,Realtime-RT-PCR方法检测该启动子在不同细胞中启动Zs GREEN基因表达的活性。结果表明:经克隆测序,得到了465bp OSP-1启动子序列,重组质粒转染卵巢颗粒细胞、Hela细胞可以观察到绿色荧光。Realtime-RT-PCR结果显示:Zs GREEN基因在卵巢颗粒细胞、Hela细胞中高表达,在肌细胞中表达量极低;说明OSP-1启动子可驱动外源基因在猪卵巢颗粒细胞中高效表达,可为构建可用于猪卵巢颗粒细胞的表达载体提供了启动子。     

一类特殊路口的多相位模糊交通控制

模糊控制不需建立被控对象的精确数学模型,特别适用于具有较大随机性的城市交通控制。对一类特殊路口的交通流进行了分析,确定了相应的信号配时方案。提出了以当前相的主队列和后继相的主队列共同决定信号配时的模糊控制方法,阐述了模糊控制器的整个设计过程。以通过交叉口的平均车辆延误为性能评价指标进行了仿真实验,仿真结果表明模糊控制优于定时控制。     

The stability for the hyperneutral type nonlinear time varying control systems (1)

We discuss the equivalence problem of hyperneutral type nonlinear time varying control system and linear time varying control system in the theory of stabilization. Making use of the symmetric positive definite solution of Riccati matrix differential equation which corresponds to the linear time varying control system, we construct the Lyapunov function. Then we provide the sufficent conditions which make that the zero solution of the hyperneutral type nonlinear time varying control systems is uniformly asymptotically stable by means of the Lyapunov equivalence decomposition method, and find the formulaes which can be used to estimate the bounds of the time delays and the nonlinear terms. Mong Peiyuan: born in 1950, Associate professor Supported by the Natural Science Foundation of Hubei Province Education Committee. Project code: 97A080     

基于边依赖平均驻留时间方法的采样系统镇定问题

该文研究了采样控制系统的镇定问题.首先,根据控制输入是否丢失将采样系统建模为切换时滞系统.采用可容许边依赖平均驻留时间方法设计切换信号,此切换信号由快速和慢速可容许边依赖平均驻留时间方法组成.应用多Lyapunov函数方法,得到了保证系统指数稳定的相关结论.最后,仿真结果验证了所得结果的有效性.     

专题报道Ⅰ：松材线虫病致病机理与病害防治（执行主编 叶建仁）专题编者按

松材线虫病是在我国发生最严重的毁灭性森林病害,已经在10多个省市区造成了严重的经济和生态损失。该病害原产地为北美洲,自20世纪初先后传入东亚的日本、中国和韩国等,给这些国家的松林带来了巨大的破坏。我国于1982年首次在南京发现松材线虫病,40年来病害一直在不断扩展蔓延。至2021年底,我国有19个省（自治区、直辖市）的728个县级行政区被划分为疫区,当年病死松树达到数千万株,防控形势异常严峻。本专题针对当前松材线虫病流行与防控中的一些热点和难点问题,围绕分子致病机理、疫源追溯和病害防治方法等方面开展研究,通过RNA干扰、基因重组和酵母转化实验明确松材线虫性别分化基因和热激转录因子在生长发育过程中和性别分化中具有的重要作用;以新一代测序技术、分子标记手段研究分析松材线虫在我国的种群分化情况,揭示不同线虫类群与地理区域间呈现的相关性;利用微生物培养、浸渍提取法和生理生化指标测定等方法,筛选并获得一系列对松材线虫具有明显拮抗作用的腐生线虫、松树内生细菌和植物提取物。本专题研究内容有助于深入解析松材线虫病在我国的传播蔓延规律,揭示松材线虫致病关键基因功能,提出病害防控的新方法,从而为更好地防控这一重大外来入侵物种引起的病害提供重要的理论和实践支撑。     

转录调节因子DEC1的研究进展

DEC1（Differentiated embryo-chondrocyte expressed gene1）是一个碱性螺旋一环一螺旋（bHLH）结构的转录因子,在软骨形成、神经发生、免疫应答、分子钟的调控、细胞分化、肿瘤的发生中起着重要的作用。DEC1还是一个缺氧调节基因,与肿瘤细胞在缺氧环境下存活密切相关,可调控肿瘤细胞生长、凋亡相关因子如缺氧诱导因子1α、转化生长因子-β、信号转导和转录激活因子、P53等的表达。DEC1还可通过调节同一家族的分子如DEC2的表达来调节细胞的功能。本文就其研究进展加以概述。