高等植物叶片中的硝酸还原酶活性稳定因子

从小麦、油菜、浮萍、番茄、烟草的叶片中分离得到NR-SF。不同植物材料中NR及NR-SF能起交叉反应;不同NR-SF影响NR酶动力学性质相同;不同NR-SF的凝胶电泳谱带显示蛋白和糖蛋白性质。NR-SF广泛存在于植物细胞中。     

在高浓度1,4-丁二醇中酶促合成去B链C端六肽胰岛素

用含80％1,4-丁二醇的混合溶剂,以胰蛋白酶酶促,由去八肽胰岛素(DOI)合成了去六肽胰岛素(DHI),总产率为35％。1,4-丁二醇的溶解性能好,在浓度高达80—90％时不明显抑制酶活力,DOI的氨基无需保护,溶液中无高聚物或沉淀形成。     

Lobula plate and ocellar interneurons converge onto a cluster of descending neurons leading to neck and leg motor neuropil in Calliphora erythrocephala

Summary In the fly, Calliphora erythrocephala, a cluster of three Y-shaped descending neurons (DNOVS 1–3) receives ocellar interneuron and vertical cell (VS4–9) terminals. Synaptic connections to one of them (DNOVS 1) are described. In addition, three types of small lobula plate vertical cell (sVS) and one type of contralateral horizontal neuron (Hc) terminate at DNOVS 1, as do two forms of ascending neurons derived from thoracic ganglia. A contralateral neuron, with terminals in the opposite lobula plate, arises at the DNOVS cluster and is thought to provide heterolateral interaction between the VS4–9 output of one side to the VS4–9 dendrites of the other. DNOVS 2 and 3 extend through pro-, meso-, and metathoracic ganglia, branching ipsilaterally within their tract and into the inner margin of leg motor neuropil of each ganglion. DNOVS 1 terminates as a stubby ending in the dorsal prothoracic ganglion onto the main dendritic trunks of neck muscle motor neurons. Convergence of VS and ocellar interneurons to DNOVS 1 comprises a second pathway from the visual system to the neck motor, the other being carried by motor neurons arising in the brain. Their significance for saccadic head movement and the stabilization of the retinal image is discussed.     

Myocardial S-adenosylhomocysteine hydrolase is important for adenosine production during normoxia

(1) The coronary vasodilator adenosine can be formed in the heart by breakdown of AMP or S-adenosylhomocysteine (SAdoHcy). The purpose of this study was to get insight into the relative importance of these routes of adenosine formation in both the normoxic and the ischemic heart. (2) A novel HPLC method was used to determine myocardial adenosine and SAdoHcy. Accumulation of SAdoHcy was induced in isolated rat hearts by perfusion with L-homocysteine thiolactone or L-homocysteine. The release of adenosine, inosine, hypoxanthine, xanthine and uric acid was determined. Additional in vitro experiments were performed to determine the kinteic parameters of S-adenosylhomocysteine hydrolase. (3) During normoxia the thiolactone caused a concentration-dependent increase in SAdoHcy. At 2000 μM of the thiolactone an SAdoHcy accumulation of 0.49 nmol/min per g wet weight was found during normoxia. L-Homocysteine (200 μM) caused an increased of 0.37 and 4.17 nmol SAdony/soc per g wet weight during normaxia and ischemia, respectively. (4) The adenosine concentration in ischemic hearts was significantly lower when homocysteine was infused (6.2 vs. 115 nmol/g; P < 0.05). Purine release was increased 4-fold during ischemia. (5) The K_m for hydrolysis of SAdoHcy was about 12 μM. At in vitro conditions favoring near-maximal SAdoHcy synthesis (72 μM adenosine, 1.8 mM homocysteine), the synthesis rate in homogenates was 10 nmol/min per g wet weight. (6) From the combined in vitro and perfusion studies, we comclude that S-adenosylhomocysteine hydrolase can contribute significantly to adenosine production in normoxic rat heart, but not during ischemia.     

miR-145通过靶向吞噬和细胞活力蛋白1抑制乳腺癌细胞侵袭

吞噬和细胞活力蛋白1（engulfment and cell motility protein 1,ELMO1）可以促进多种癌细胞的侵袭和转移,但ELMO1的表达是否受miRNA的调控鲜有研究。本研究旨在探讨miR-145与ELMO1表达的相关性,以及miR-145通过结合ELMO1的mRNA对乳腺癌侵袭的影响。通过TargetScan (http://www.targetscan.org/)靶基因预测软件预测与ELMO1的3′UTR结合的miR-145。荧光素酶结果证实两者互补结合。Transwell侵袭结果显示,miR-145组和siELMO1+miR-145组MDA-231乳腺癌细胞穿膜数较对照组分别降低40%（P＜0.05）和79%（P＜0.05）。siELMO1+miR-145组和siELMO1组细胞穿膜数则无显著差异（P>0.05）。结果提示,miR-145通过与ELMO1的mRNA结合抑制细胞侵袭。qRT-PCR显示,低侵袭的MCF-7乳腺癌细胞miR-145的表达量较高侵袭的MDA-435细胞高80%（P＜0.05）,较MDA-231乳腺癌细胞高75%（P＜0.05）,即miR-145与癌细胞侵袭能力呈负相关。Western印迹结果表明,miR-145组ELMO1表达量低于阴性对照组,miR-145 抑制组ELMO1表达量高于抑制剂NC组（P＜0.05）,证明miR-145抑制ELMO1的表达。qRT-PCR显示,过表达miR-145后ELMO1 mRNA含量与对照组无显著差异（P>0.05）。结果提示,miR-145对ELMO1的调控作用通过抑制其翻译实现。F-肌动蛋白聚合实验表明,miR-145组和阴性对照组于20 s和60 s时F-肌动蛋白聚合结果存在明显区别（P＜0.05）。Western 印迹结果表明,miR-145组活化的Rac1表达量较阴性对照组降低60%（P<0.05）,抑制剂NC组活化的Rac1较miR-145 抑制组降低55%（P<0.05）;miR-145组磷酸化的整合素β1较对照组于15 min时降低42%（P<0.05）,于30 min时降低31%（P<0.05）。由此得出的miR-145过表达显著促进乳腺癌细胞F-肌动蛋白聚合、Rac1活化和整合素β1磷酸化结论。综上所述,miR-145通过靶向ELMO1的 mRNA抑制ELMO1翻译,从而抑制乳腺癌的侵袭。     

肿瘤坏死因子受体超家族成员在免疫系统和疾病中的研究

肿瘤坏死因子受体超家族 (tumor necrosis factor receptor superfamily, TNFRSF) 是细胞因子受体的一个蛋白质超家族,其显著特征是通过细胞外富含半胱氨酸结构域结合肿瘤坏死因子(tumor necrosis factor,TNF)。肿瘤坏死因子受体(tumor necrosis factor receptors,TNFRs)是古老的细胞因子,TNFRs同源基因最早可追溯到节肢动物果蝇中。TNFRs在炎症反应、细胞凋亡、淋巴细胞稳态和组织发育中发挥重要的作用,TNFRs最主要的功能是与免疫系统相关。鉴于其在免疫系统中发挥重要的作用,肿瘤坏死因子受体家族成员已成为治疗糖尿病、动脉粥样硬化、骨质疏松、自身免疫性疾病、移植排斥反应和癌症等人类疾病的靶点。随着科学技术发展,关于TNFRs的功能有了新的进展,在无脊椎动物和低等脊椎动物中已经有大量报道。在本篇综述中,主要总结了在高等哺乳动物中发现的29种TNFR成员的相关报道,包括8种死亡受体和21种非死亡受体,主要涉及在免疫系统以及与疾病相关领域的研究。大多数研究处于基础实验阶段,少数走向临床研究的案例取得的临床效果并不理想,靶向设计针对自身免疫性疾病、炎症和肿瘤疾病的治疗方案需要更深入的理解TNFRs功能。本文旨在对TNFRs成员发挥的功能有进一步的认识。     

Effects of fructose on human fibroblast metabolism: the application of DNA measurements as a basis for interpretation

Summary A fluorometric procedure for measuring DNA was used to study growth and metabolic responses of eight cell strains of human foreskin fibroblasts. In preliminary studies this procedure gave more precise specific activity changes inN-acetyl-β-d-glucosaminidase (NAG) than did a protein activity basis, when changes in this enzyme's specific activity were investigated as a function of experimental cell manipulation. When fibroblast growth in eight cell strains was compared in 134 mM d-fructose vs. 13.4 mM glucose-supplemented minimum essential media, a significant increase in cellular DNA (50%) and protein (45%) occurred over an 11-d period. No significant differences in media pH change, lactate production, or carbohydrate uptake occurred on a DNA basis when cell metabolism was compared over the last 24 h of culture in the two media. Cells grown in fructose-containing media tended to show a reduction in NAG specific activity when compared with those grown in glucose-containing media.     

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。     

苯胺嘧啶衍生物X-9通过下调整合素β1表达抑制肝细胞癌迁移侵袭

整合素在许多肿瘤细胞中高表达,并且参与肿瘤细胞的侵袭转移。在肝细胞癌中,整合素β1被报导高表达,并促进肿瘤细胞的侵袭。目前,对于整合素的表达调控癌细胞机制以及干预其表达进而抑制肿瘤细胞转移的研究较少。本研究探讨利用小分子化合物抑制整合素表达来抑制肿瘤细胞迁移和侵袭的可能。首先,对临床肝癌细胞患者癌组织和癌旁组织中的整合素β1的表达进行检测,发现其在癌组织中的表达显著高于癌旁组织（P<0.05）。对TCGA肿瘤数据库的生物信息学分析结果同样显示,整合素β1的高表达与肝癌的分期（P=0.019）和预后（P=0.013）相关。通过筛选发现,苯胺嘧啶衍生物X09可以抑制肝癌细胞中整合素β1的mRNA和蛋白质的表达（P<0.01）。细胞划痕愈合实验和细胞穿孔实验结果显示,苯胺嘧啶衍生物X-9能够抑制肝癌细胞的迁移和侵袭（P<0.01）。进一步的研究证实,在肝癌细胞中外源表达整合素β1可以逆转X-9对肝癌细胞迁移和侵袭的抑制;而在敲低整合素β1的细胞中,X-9对细胞的迁移和侵袭的抑制被消除。因此,鉴定出苯胺嘧啶衍生物X-9可以通过下调整合素β1表达,进而抑制肝癌细胞的迁移和侵袭。