Design and synthesis of Hsp90 inhibitors: Exploring the SAR of Sansalvamide A derivatives

Utilizing the structure–activity relationship we have developed during the synthesis of the first two generations and mechanism of action studies that point to the interaction of these molecules with the key oncogenic protein Hsp90, we report here the design of 32 new Sansalvamide A derivatives and their synthesis. Our new structures, designed from previously reported potent compounds, were tested for cytotoxicity on the HCT116 colon cancer cell line, and their binding to the biological target was analyzed using computational studies involving blind docking of derivatives using Autodock. Further, we show new evidence that our molecules bind directly to Hsp90 and modulate Hsp90’s binding with client proteins. Finally, we demonstrate that we have integrated good ADME properties into a new derivative.     

蛋白质复合体非变性凝胶电泳技术及其应用新进展

非变性凝胶电泳技术是研究蛋白质复合体的强有力工具。重点介绍了蓝绿温和非变性凝胶电泳(BN-PAGE)技术的原理和特点,比较了由BN-PAGE衍生的蓝色温和琼脂糖凝胶电泳、清澈温和非变性凝胶电泳(CN-PAGE)和高分辨清澈温和非变性凝胶电泳(HrCN-PAGE)技术的差异和适用范围,并概括地介绍了这些技术在植物蛋白质复合体研究中应用的新进展。     

PCR-SSCP的效果分析

PCR-SSCP是一种以PCR为基础的单链构象多态性分析技术,是DNA已知突变的检测或未知变异分析中常用和实用的技术之一。影响SSCP试验效果的因素有很多,本研究主要对凝胶浓度和是否添加甘油两个因素进行分析与探讨。结果表明,凝胶浓度12%和添加甘油终浓度10%的条件下可以得到满意的结果。     

21例人流术后节育器嵌顿致滞留或残留于宫内取出的临床分析

目的探讨带器妊娠行人工流产术后节育器嵌顿致滞留或残留于宫内患者取出节育器的效果。方法回顾性分析2006年2月～2009年12月期间在永康市计划生育指导站21例患者的临床资料。结果21例在B超引导下,均成功取出。结论对放置IUD的妇女要定期复查,对放置IUD避孕失败的妇女,明确宫腔内是否有IUD,做到早发现,早诊断,及时正确地处理。     

TWO SPECIFIC CAUSES OF CELL MORTALITY IN FREEZE‐THAW CYCLE OF YOUNG THALLI OF PORPHYRA YEZOENSIS (BANGIALES,RHODOPHYTA)1

Porphyra yezoensis Ueda is an important marine aquaculture crop with single‐layered gametophytic thalli. In this work, the influences of thallus dehydration level, cold‐preservation (freezing) time, and thawing temperature on the photosynthetic recovery of young P. yezoensis thalli were investigated employing an imaging pulse‐amplitude‐modulation (PAM) fluorometer. The results showed that after 40 d of frozen storage when performing thallus thawing under 10°C, the water content of the thalli showed obvious effects on the photosynthetic recovery of the frozen thalli. The thalli with absolute water content (AWC) of 10%–40% manifested obvious superiority compared to the thalli with other AWCs, while the thalli thawed at 20°C showed very high survival rate (93.10%) and no obvious correlation between thallus AWCs and thallus viabilities. These results indicated that inappropriate thallus water content contributed to the cell damage during the freeze‐thaw cycle and that proper thawing temperature is very crucial. Therefore, AWC between 10% and 40% is the suitable thallus water content range for frozen storage, and the thawing process should be as short as possible. However, it is also shown that for short‐term cold storage the Porphyra thallus water content also showed no obvious effect on the photosynthetic recovery of the thalli, and the survival rate was extremely high (100%). These results indicated that freezing time is also a paramount contributor of the cell damage during the freeze‐thaw cycle. Therefore, the frozen nets should be used as soon as time permits.     

A ONE‐SHOT SOLUTION TO BACTERIAL AND FUNGAL CONTAMINATION IN THE GREEN ALGA CHLAMYDOMONAS REINHARDTII CULTURE BY USING AN ANTIBIOTIC COCKTAIL1

Keeping sterile stocks or cultures of microalgae is fundamental to microalgae biotechnology as well as basic scientific research. However, contamination by bacteria and/or fungi in microalgae cultures or stocks is often a problem. Here, we have developed a strategy for reducing or eliminating bacterial and fungal contamination by using a cocktail of antibiotics. Chlamydomonas reinhardtii P. A. Dang., a widely used unicellular green alga, has been used as a testing organism. A combination of ampicillin, cefotaxime, and carbendazim removed or reduced contamination by three different bacteria and two different fungi tested. A step‐by‐step procedure is provided, which is simple, economical, and effective.     

Structural Evidence of Glycoprotein Assembly in Cellular Membrane Compartments prior to Alphavirus Budding

Membrane glycoproteins of alphavirus play a critical role in the assembly and budding of progeny virions. However, knowledge regarding transport of viral glycoproteins to the plasma membrane is obscure. In this study, we investigated the role of cytopathic vacuole type II (CPV-II) through in situ electron tomography of alphavirus-infected cells. The results revealed that CPV-II contains viral glycoproteins arranged in helical tubular arrays resembling the basic organization of glycoprotein trimers on the envelope of the mature virions. The location of CPV-II adjacent to the site of viral budding suggests a model for the transport of structural components to the site of budding. Thus, the structural characteristics of CPV-II can be used in evaluating the design of a packaging cell line for replicon production.Semliki Forest virus (SFV) is an enveloped alphavirus belonging to the family Togaviridae. This T=4 icosahedral virus particle is approximately 70 nm in diameter (30) and consists of 240 copies of E1/E2 glycoprotein dimers (3, 8, 24). The glycoproteins are anchored in a host-derived lipid envelope that encloses a nucleocapsid, made of a matching number of capsid proteins and a positive single-stranded RNA molecule. After entry of the virus via receptor-mediated endocytosis, a low-pH-induced fusion of the viral envelope with the endosomal membrane delivers the nucleocapsid into the cytoplasm, where the replication events of SFV occur (8, 19, 30). Replication of the viral genome and subsequent translation into structural and nonstructural proteins followed by assembly of the structural proteins and genome (7) lead to budding of progeny virions at the plasma membrane (18, 20). The synthesis of viral proteins shuts off host cell macromolecule synthesis, which allows for efficient intracellular replication of progeny virus (7). The expression of viral proteins leads to the formation of cytopathic vacuolar compartments as the result of the reorganization of cellular membrane in the cytoplasm of an infected cell (1, 7, 14).Early studies using electron microscopy (EM) have characterized the cytopathic vacuoles (CPVs) in SFV-infected cells (6, 13, 14) and identified two types of CPV, namely, CPV type I (CPV-I) and CPV-II. It was found that CPV-I is derived from modified endosomes and lysosomes (18), while CPV-II is derived from the trans-Golgi network (TGN) (10, 11). Significantly, the TGN and CPV-II vesicles are the major membrane compartments marked with E1/E2 glycoproteins (9, 11, 12). Inhibition by monensin results in the accumulation of E1/E2 glycoproteins in the TGN (12, 26), thereby indicating the origin of CPV-II. While CPV-II is identified as the predominant vacuolar structure at the late stage of SFV infection, the exact function of this particular cytopathic vacuole is less well characterized than that of CPV-I (2, 18), although previous observations have pointed to the involvement of CPV-II in budding, because an associated loss of viral budding was observed when CPV-II was absent (9, 36).In this study, we characterized the structure and composition of CPV-II in SFV-infected cells in situ with the aid of electron tomography and immuno-electron microscopy after physical fixation of SFV-infected cells by high-pressure freezing and freeze substitution (21, 22, 33). The results revealed a helical array of E1/E2 glycoproteins within CPV-II and indicate that CPV-II plays an important role in intracellular transport of glycoproteins prior to SFV budding.