Detecting chimeric 5''''l3''''UTRs with cross-chromosomal splicing by bioinformatics

The 5'/3' UTRs of mRNA are crucial in transla-tional regulation, and several serious diseases are believed tobe associated with abnormal splicing of these parts of themRNA sequence. In this work a novel method which usessequence alignment database searching for detecting chi-meric 5'3' UTRs with cross-chromosomal splicing is reported.Eight highly credible instances of cross-chromosomal splic-ing have been found using this method, representing addi-tional confirmation of the existence of cross-chromosomalsplicing events provided by bioinformatics tools. Since noconserved motif has been found in any of the eight instances,and at the same time current prediction algorithms produceonly trivial secondary structures at the "splicing sites", it isnot possible to identify any specific signal leading to thesplicing.     

圆褐固氮菌荚膜染色法改进的研究

本文报导了圆褐固氮菌荚膜染色的一种新方法。此法简单快速、重复性好、对比清晰:且取材容易、标本易于保存。     

Sumoylation regulates diverse biological processes

Ten years after its discovery, the small ubiquitin-like protein modifier (SUMO) has emerged as a key regulator of proteins. While early studies indicated that sumoylation takes place mainly in the nucleus, an increasing number of non-nuclear substrates have recently been identified, suggesting a wider stage for sumoylation in the cell. Unlike ubiquitylation, which primarily targets a substrate for degradation, sumoylation regulates a substrate’s functions mainly by altering the intracellular localization, protein-protein interactions or other types of post-translational modifications. These changes in turn affect gene expression, genomic and chromosomal stability and integrity, and signal transduction. Sumoylation is counter-balanced by desumoylation, and well-balanced sumoylation is essential for normal cellular behaviors. Loss of the balance has been associated with a number of diseases. This paper reviews recent progress in the study of SUMO pathways, substrates, and cellular functions and highlights important findings that have accelerated advances in this study field and link sumoylation to human diseases. Received 19 March 2007; received after version 16 July 2007; accepted 1 August 2007     

Molecular genetics of RecQ helicase disorders

The RecQ helicases belong to the Superfamily II group of DNA helicases, and are defined by amino acid motifs that show sequence similarity to the catalytic domain of Escherichia coli RecQ. RecQ helicases have crucial roles in the maintenance of genome stability. In humans, there are five RecQ helicases and deficiencies in three of them cause genetic disorders characterised by cancer predisposition, premature aging and/or developmental abnormalities. RecQ helicase-deficient cells exhibit aberrant genetic recombination and/or DNA replication, which result in chromosomal instability and a decreased potential for proliferation. Here, we review the current knowledge of the molecular genetics of RecQ helicases, focusing on the human RecQ helicase disorders and mouse models of these conditions. Received 9 March 2007; received after revision 26 April 2007; accepted 2 May 2007     

胶质芽孢杆菌荚膜染色方法的比较与改进

荚膜是细菌的重要附属物,细菌有无荚膜以及荚膜物质厚度和化学组成是其重要特征之一.染色和观察荚膜形态是微生物研究中的基本技能,但荚膜的低折光性与亲和染料能力差等特性,使其不易着色,制作一张好的荚膜染色玻片需要正确的染色方法和一定的熟练程度.胶质芽孢杆菌(Bacillus mucilaginosus)以其肥厚荚膜为显著特征,该菌的许多有益特性都与其产生肥厚荚膜有密切关系.本文以该菌为试验对象,尝试采用7种负染方法对荚膜进行染色.结果表明:7种染色方法中,墨汁染色法和刚果红盐酸染色法简便快速且效果较好;对刚果红盐酸染色法进行了改进,使染色效果更为理想,该方法值得推广.     

白木香染色体制片方法的研究

为获得清晰的染色体图像,应用改良去壁低渗法对白木香茎尖的染色体标本制备进行了探讨,并比较了2种不同预处理方法制片的效果以及不同的预处理时间对细胞中期分裂相的影响．结果表明,选取早上9点钟左右的茎尖,用w=0．1％的秋水仙素溶液预处理2h后固定24h,再用w=2％的纤维素酶和埘：0．5％的果胶酶混合酶液于37℃下进行2h的酶解,低渗后制备染色体标本,能获得分散良好、清晰的染色体图像．首次确定了白木香的染色体数目（2n）为16条．     

十二烷基硫酸钠-聚丙烯酰胺凝胶电泳的实验教学改进

在本科生物化学实验教学中,为减少有机溶剂的使用,同时缩短实验时间,作者对SDS-PAGE的脱色过程进行改进,使用0.5mol/L NaC l代替含挥发性有机溶剂做脱色液,取得了良好的实验效果。     

大鼠DAI特殊染色观察及NF-κB的表达

为了分析大鼠弥漫性轴索损伤(DAI)后病理学变化及核因子-κB(NF-κB)的表达,探讨了NF-κB在弥漫性轴索损伤中的作用,构建了大鼠DAI动物模型.运用Glees-Marsland染色法和Weil氏染色法观察伤后不同时间段的病理学改变,并运用免疫组化SABC法观察NF-κB的表达.实验结果表明,大鼠弥漫性轴索损伤后1h即可观察到部分轴索肿胀、断裂,髓鞘水肿、分层等现象,24h可见典型轴索收缩球形成,髓鞘崩解呈筛网状改变,72h轴索断裂数量、范围及髓鞘筛网状改变达到高峰;伤后1h,脑组织内可见NF-κB阳性细胞,伤后3h阳性细胞数增多,伤后24h达到高峰,持续到72h,伤后7d,仍可见阳性细胞表达,但数量减少.对照组细胞核未见阳性表达.大鼠弥漫性轴索损伤后NF-κB表达增加,可能与轴索继发性损伤有关.     

细胞石蜡包埋切片技术的应用

目的:研究使用蛋清甘油作为支撑物的石蜡包埋制片技术用于基于细胞的形态学检测的可行性.方法:针对人胃癌BGC-823培养细胞、临床送检宫颈TCT检查细胞、胃癌标本残碎细胞液等细胞学材料,运用蛋清甘油作为支撑物进行石蜡包埋制片,进行HE染色及免疫细胞化学染色,并将染色效果与细胞爬片、细胞甩片及细胞涂片染色效果进行对照分析....     

鸡早期胚染色体畸变及其微核研究

研究了“星杂２８８”和“京白９０４”两品种种鸡，提出了各种染色体畸变类型的百分率，并对产生机制进行了初步探讨，雏鸡骨髓细胞的观察，得出了两品种鸡微核的自然发生率分别是２．７４％和２．９８％。