环状RNA在肝细胞癌中的作用及机制

肝细胞癌（hepatocellular carcinoma,HCC）治疗困难、预后很差,是肿瘤相关死亡中的第4大癌症,严重危害人类生命健康,但其具体发病机制却仍未完全阐明。因此,探索能调控肝细胞癌发生发展,作为肝细胞癌的诊断标志物或能预测患者预后的关键分子仍十分必要。环状RNA是前体mRNA通过反向剪接产生的由3′, 5′ 磷酸二酯键首尾连接形成的共价闭合环状结构,主要有外显子circRNA（exonic circRNA,ecircRNA）、环状内含子RNA（circular intronic RNA,ciRNA）及外显子 内含子circRNA（exon-intron circRNA,EIciRNA）三大类。由于环状RNA具有普遍性、高度保守性和稳定性,其可以参与多种癌症的发生发展过程,并且可作为肿瘤的早期诊断标志物及预后因子,因此,这是一类新型且非常有潜力应用于临床诊治各阶段的分子。近年来,有大量关于环状RNA与肝细胞癌的研究。这些研究表明,环状RNA在肝细胞癌发生发展进程中发挥的作用十分重要,并且其机制多样。因此,本文主要关注环状RNA在肝细胞癌中的最新进展,总结不同环状RNA分子对于肝细胞癌细胞恶性表型、肿瘤干细胞及肿瘤微环境中免疫细胞的作用,以及其在肝细胞癌临床转移、分期、诊断、预后等各阶段中发挥的功能及其具体作用机制。此外,本文还提出了目前研究中存在的一些问题和不足,以期为未来的研究提供一些新的思路及策略。     

长非编码RNA PVT1与消化系统肿瘤

长非编码RNA（long non-coding RNAs, lncRNAs）在肿瘤发生、发展进程中承担重要角色,是近年来的研究热点之一。大量研究表明,浆细胞瘤变异易位基因1（plasmacytoma variant translocation 1, PVT1）可通过多种分子机制参与调控消化系统肿瘤的增殖凋亡、迁移侵袭、细胞自噬、血管生成、多药耐药及肿瘤代谢等过程,从而发挥致癌作用。本文主要就PVT1在消化系统肿瘤中的表达水平变化,及其与临床病理特征和预后的关系,以及PVT1对消化系统肿瘤的致癌作用机制和多药耐药机制等研究进展作一综述。     

应用酶联免疫吸附试验检测马铃薯卷叶病毒

以辣根过氧化物酶标记马铃薯卷叶病毒抗体,采用双抗体夹心ELISA方法鉴定了马铃薯和洋酸浆的茎、叶、根及马铃薯块茎中的马铃薯卷叶病毒(Potato Leafroll Virus,PLRV),结果表明,对提纯的PLRV可测出的最低浓度为25ng/ml,当包被抗体浓度为40μg/ml、酶标记抗体稀释度为1/120时,可测出马铃薯茎、叶和根汁液中的PLRV,感染PLRV的洋酸浆茎、叶和根汁液的消光值,均比无病对照者高二倍以上,虽然感染PLRV的马铃薯休眠块茎维管束组织汁液的消光值高于无病毒对照,且脐部维管束组织消光值高于顶端,但测定打破休眠的感病块茎顶端维管束组织的阳性结果更为可靠和明显。     

鄱阳湖水生植被

本文列出了鄱阳湖98种水生维管束植物的名录,叙述了水生植被的分布。鄱阳湖水生植被面积为2262平方公里,占全湖总面积的80．8％。湖中植被呈不规则环带状分布,并可划分为湿生、挺水、浮叶和沉水4个植物带,9个主要植物群丛。并研究了鄱阳湖水生植被的演变及发展趋势和湖水位的季节性变化对植被的影响。     

亚洲高海拔锄足蟾属间分类研究(Amphibia:Pelobatidae)

本文比较研究了高海拔锄足蟾类29种成体和蝌蚪的外形,25种的骨骼,8种的核型和带型,9种的眼晶体薄层凝胶等电聚焦电泳图谱等性状,并结合地理分布、生态环境及习性等因素综合而较全面地对中国锄足蟾科Pelobatidae的齿突蟾属Scutiger,猫眼蟾属Aelurophryne和齿蟾属Oreo-lalax三个类群的属间分类问题进行了探讨。研究表明:齿蟾属Oreolalax应为有效属,不宜作为齿突蟾属Scutiger的亚属;猫眼蟾属Aelurophryne与齿突蟾属Scutiger应同归一属,前者应为后者之亚属。     

猪尾猴疟原虫（P.inui）广西株配子体感染性变化规律的实验研究

用P.inui广西株经蚊传和血传接种4只猴子,让大劣按蚊每6小时吸血感染1次,连续数周,以蚊胃感染情况判断配子体的感染性。结果发现:本虫株配子体发育成熟的需72n+K小时;配子体生理寿命约12小时;配子体的感染性具有每隔2天,在后半夜出现高峰的周期性变化;血中大环状体百分比高峰与蚊媒感染高峰一致。     

Time-Dependent Increase in Protein Phosphorylation Following One-Trial Enhancement in Hermissenda

Abstract: One-trial conditioning of the nudibranch mollusk Hermissenda produces short- and long-term changes in excitability (enhancement) of identified sensory neurons. To investigate the biochemical mechanisms underlying this example of plasticity, we have examined changes in protein phosphorylation at different times following the in vitro conditioning trial. Changes in the incorporation of ³²PO₄ into proteins were determined using two-dimensional polyacrylamide gel electrophoresis, autoradiography, and densitometry. Conditioning resulted in increases in levels of several phosphoproteins, five of which, ranging in apparent molecular mass from 22 to 55 kDa, were chosen for analysis. The increased phosphorylation of the 46- and 55-kDa phosphoproteins detected 2 h postconditioning was significantly greater than the level of phosphorylation detected in an unpaired control group, indicating that long-term enhancement is pairing specific. Statistically significant increases in phosphorylation as compared with the control group that received only light were detected immediately after conditioning (5 min) for the 55-, 46-, and 22-kDa phosphoproteins, at 1 h for the 55- and 46-kDa phosphoproteins, and at 2 h for the 55-, 46-, and 22-kDa phosphoproteins. The 46- and 55-kDa phosphoproteins are putative structural proteins, and the 22-kDa phosphoprotein is proposed to be a protein kinase C substrate previously identified in Hermissenda following multitrial classical conditioning. Time-dependent increases in protein phosphorylation may contribute to the induction and maintenance of different memory stages expressed in sensory neurons after one-trial conditioning.     

A SPOROPHYTE CELL WALL PROTEIN OF THE RED ALGA PORPHYRA PURPUREA (RHODOPHYTA) IS A NOVEL MEMBER OF THE CHYMOTRYPSIN FAMILY OF SERINE PROTEASES1

A complementary DNA (cDNA) clone from a Porphyra purpurea (Roth) C. Agardh sporophyte-specific subtracted cDNA library was found to encode a protein similar to serine proteases of the chymotrypsin class. The encoded protein contains a typical signal peptide and is particularly similar to chymotrypsins in the regions surrounding the active site residues and the activation site where cleavage of the propeptide occurs. In addition, the six cysteine residues characteristic of chymotrypsins are conserved. However, two of the three residues of the active site His/Asp/Ser charge relay triad have been replaced, indicating that the protein is unlikely to have peptidase activity. Northern hybridization confirmed that this cDNA is derived from an abundant, sporophyte-specific messenger RNA (mRNA). The presence of signal peptide on the encoded protein and the abundance of its mRNA suggested that this protein might be localized in the cell wall. Consequently, sporophyte cell walls were isolated and a major protein having a molecular weight similar to that estimated for the encoded protein was purified. N-terminal sequence analysis indicated that this cell wall protein is identical to that encoded by the cDNA with the amino terminus of the mature protein beginning at the activation site. This cell wall structural protein appears to have evolved from a chymotrypsin-like progenitor but has been adapted to bind cell wall proteins and/or polysaccharides rather than to cleave proteins.