G-quadruplex inducer/stabilizer pyridostatin targets SUB1 to promote cytotoxicity of a transplatinum complex

Pyridostatin (PDS) is a well-known G-quadruplex (G4) inducer and stabilizer, yet its target genes have remained unclear. Herein, applying MS proteomics strategy, we revealed PDS significantly downregulated 22 proteins but upregulated 16 proteins in HeLa cancer cells, of which the genes both contain a number of G4 potential sequences, implying that PDS regulation on gene expression is far more complicated than inducing/stabilizing G4 structures. The PDS-downregulated proteins consequently upregulated 6 proteins to activate cyclin and cell cycle regulation, suggesting that PDS itself is not a potential anticancer agent, at least toward HeLa cancer cells. Importantly, SUB1, which encodes human positive cofactor and DNA lesion sensor PC4, was downregulated by 4.76-fold. Further studies demonstrated that the downregulation of PC4 dramatically promoted the cytotoxicity of trans-[PtCl₂(NH₃)(thiazole)] (trans-PtTz) toward HeLa cells to a similar level of cisplatin, contributable to retarding the repair of 1,3-trans-PtTz crosslinked DNA lesion mediated by PC4. These findings not only provide new insights into better understanding on the biological functions of PDS but also implicate a strategy for the rational design of novel multi-targeting platinum anticancer drugs via conjugation of PDS as a ligand to the coordination scaffold of transplatin for battling drug resistance to cisplatin.     

The role of ubiquitination and deubiquitination in tumor invasion and metastasis

Ubiquitination is vital for multiple cellular processes via dynamic modulation of proteins related to cell growth, proliferation, and survival. Of the ubiquitination system components, E3 ubiquitin ligases and deubiquitinases have the most prominent roles in modulating tumor metastasis. This review will briefly summarize the observations and underlying mechanisms of multiple E3 ubiquitin ligases and deubiquitinases to regulate tumor metastasis. Further, we will discuss the relationship and importance between ubiquitination components and tumor progression.     

Rapid Identification of Probiotic Lactobacillus Biosurfactant Proteins by ProteinChip Tandem Mass Spectrometry Tryptic Peptide Sequencing

A novel ProteinChip-interfaced tandem mass spectrometer was employed to identify collagen binding proteins from biosurfactant produced by Lactobacillus fermentum RC-14. On-chip tryptic digestion of the captured collagen binding proteins resulted in rapid sequence identification of five novel tryptic peptide sequences via collision-induced dissociation tandem mass spectrometry.     

HPV16(新疆株)E6在Pichia pastoris酵母中的分泌表达

目的：利用酵母Pichia pastoris真核蛋白表达在系统,表达HPV16（新疆株）E6（HPV16 XJ E6）蛋白。方法：根据HPV16 XJ E6基因序列设计引物,并分别在5′引物和3′引物中引入了EcorRI和XbaI酶切位点,经PCR扩增后与pMD18-T载体相连,再将HPV16 XJ E6从载体上切下并克隆至穿棱质粒pGAPZαA上,获得的重组穿棱质粒pGAPZαA-E6经线性化后,采用LiCl法将重组穿棱质粒转入酵母细胞内,Zeocin^ 筛选鉴定,经小瓶发酵后,取上清作SDSPAGE检测,结果：HPV16 XJ E6成功地在酵母真核表达系统获得表达,表达产物的分子量为20kD,为深入研究HPV16 XJ E6蛋白功能奠定了理论基础。     

60Co-r射线辐照对几种植物提取物有效成份的影响

以贯叶连翘,银杏,枳实,红车轴草,当归,灵芝,茶提取物为研究对象,采用^60Co-r辐照新技术,研究了10kGy辐照剂量对它们有效成份的影响。结果表明：辐照对贯叶连翘,银杏,枳实,红车轴草,当归,灵芝几种提取物的有效成份无明显影响;辐照后绿茶提取物中儿茶素含量较对照下降5．29％,普洱茶提取物中茶多酚含量较对照增加9．45％。     

Terbium ion binding to Limuluspolyphemus hemocyanin

Terbium ion binds to calcium-free $\text{Limulus}$ hemocyanin at pH 7.0 and 8.9, and promotes the aggregation of hemocyanin subunits, a phenomenon associated with calcium binding. An excitation maximum for the bound terbium at 293 nm and the results of treating the hemocyanin with N-bromosuccinimide indicate that energy transfer from tryptophan to the bound terbium is responsible for the enhancement of terbium fluorescence. At pH 8.9, addition of calcium to hemocyanin containing bound terbium results in only a partial loss of terbium fluorescence, suggesting heterogeneity in the terbium binding sites. Titration of hemocyanin with terbium also indicates multiple binding sites.     

日本大萝卜引种栽培研究

本文报道日本大萝卜引种栽培的试验结果,并为推广这一蔬菜新品种提供了有效的栽培技术措施。     

脂肪酶在微乳液和微乳液凝胶中催化辛酸辛醇的酯化反应

脂肪酶在合成反应中具有很高的区域选择性和立体选择性 ,已广泛用于食品工业和药物工业[1,2 ] ,在有机介质中的脂肪酶催化反应已有较多研究[3 ,4 ] 。微乳液一般由表面活性剂、助表面活性剂、油和水等组份组成 ,它是一种热力学稳定、光学透明、宏观均匀而微观不均匀的体系 ,能提供酶催化所需要的巨大油 /水界面[5] 。而将脂肪酶增溶于油包水(Ｗ /Ｏ)微乳液中的纳米级“水池”中 ,可使酶以分子水平分散[6] ,图 1(ａ) ,从而可用来模拟细胞微环境中的反应。油包水微乳液中的酶可通过加入明胶而制成固定化酶 ,含明胶的微乳液凝胶 (ＭＢＧｓ)最早…     

Effect of the thymus on the capability of stromal progenitor cells for intracellular repair of radiation damage

Cells-precursors of haemopoietic microenvironment, as well as osteogenic cells-precursors, indicated with heterotopic transplantation of mouse bone marrow, can repair sublethal radiation damages. Thymectomy of the bone-marrow donors does not influence this capacity of the stromal precursors.