Gene expression changes associated with cytotoxicity identified using cDNA arrays

In order to investigate gene expression changes associated with cytotoxicity, we used cDNA arrays to monitor the expression of over 5,000 genes in response to toxic stress in the HepG2 liver cell line. Cells were treated with cytotoxic doses of acetaminophen, caffeine or thioacetamide for nine time points ranging from 1 to 24 h. Samples of mRNA from each time point were used to prepare radiolabeled cDNA, which was hybridized to nylon-membrane-based cDNA arrays. High-stringency washes were applied to reduce cross-hybridization. Analysis of spot intensities revealed that each compound led to approximately 150-250 gene expression changes that were sustained over at least three adjacent time points. The affected genes could be classified into clusters based on their temporal patterns of differential expression. A common set of 44 genes showed similar expression changes in response to all three compounds. Of these changes, 90% could be confirmed by quantitative RT-PCR analysis. The results indicate that detailed array-based time-course studies, coupled with a sensitive and highly specific confirmation assay, provide a powerful means of identifying cytotoxicity-associated gene expression changes. Electronic Publication     

双管基因枪介导的基因瞬时表达技术在拟南芥中的应用

基因瞬时表达是植物中研究目标基因功能的常用手段。在模式植物拟南芥(Arabidopsis thaliana)中, 相比原生质体和农杆菌介导的基因异源表达技术, 利用粒子轰击进行基因瞬时表达一直鲜有报道。其主要原因是拟南芥叶型相对较小、基因枪操作相对烦琐以及基因表达效率差异较大。该研究通过优化双管基因枪系统, 在营养生长旺盛的拟南芥莲座叶中实现GFP和GUS基因高效表达。同时, 通过GUS报告基因明确了坏死诱导因子BAX、Avh238和ATR13/Rpp13激发拟南芥细胞坏死的表型。但在本氏烟(Nicotiana benthamiana)中明显诱导细胞坏死的Avrblb1/RB基因对, 在拟南芥中却丧失了诱导细胞坏死的活性。由于双管基因枪系统每次轰击时设置平行对照, 可有效降低转化实验中的样本变异度, 为拟南芥及其突变体研究中准确评价基因功能和高通量筛选目标基因提供新的技术参考。     

Synthesis and antiviral properties of novel indole-based thiosemicarbazides and 4-thiazolidinones

A novel series of indolylthiosemicarbazides (6a–6g) and their cyclization products, 4-thiazolidinones (7a–7g), have been designed, synthesized and evaluated, in vitro, for their antiviral activity against a wide range of DNA and RNA viruses. Compounds 6a, 6b, 6c and 6d exhibited notable antiviral activity against Coxsackie B4 virus, at EC₅₀ values ranging from 0.4 to 2.1 μg/mL. The selectivity index (ratio of cytotoxic to antivirally effective concentration) values of these compounds were between 9 and 56. Besides, 6b, 6c and 6d also inhibited the replication of two other RNA viruses, Sindbis virus and respiratory syncytial virus, although these EC₅₀ values were higher compared to those noted for Coxsackie B4 virus. The SAR analysis indicated that keeping the free thiosemicarbazide moiety is crucial to obtain this antiviral activity, since the cyclization products (7a–7g) did not produce any antiviral effect.     

The Cap-Snatching SFTSV Endonuclease Domain Is an Antiviral Target

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