5’核苷酸酶碱性磷酸酶双重染色法在毛细淋巴管研究中的应用

本文应用5’-N-ALP双重染色法观察了裸鼠皮肤及人胃癌组织内淋巴管的形态和细微分布.在光镜下毛细淋巴管、淋巴管呈5’-N强阳性反应,管壁显示明显的棕色或深棕色,而毛细血管、血管的ALP呈强阳性,管壁呈明显的蓝色.据此可用组化方法将毛细淋巴管和毛细血管区别开来.本法能显示呈褐色的毛细淋巴管,特别是呈实性条索状的毛细淋巴管,因而双重染色比HE染色更能客观、准确地显示毛细淋巴管的分布.     

Li–Ti Cation Mixing Enhanced Structural and Performance Stability of Li‐Rich Layered Oxide

Li‐rich layered metal oxides are one type of the most promising cathode materials in lithium‐ion batteries but suffer from severe voltage decay during cycling because of the continuous transition metal (TM) migration into the Li layers. A Li‐rich layered metal oxide Li_1.2Ti_0.26Ni_0.18Co_0.18Mn_0.18O₂ (LTR) is hereby designed, in which some of the Ti⁴⁺ cations are intrinsically present in the Li layers. The native Li–Ti cation mixing structure enhances the tolerance for structural distortion and inhibits the migration of the TM ions in the TMO₂ slabs during (de)lithiation. Consequently, LTR exhibits a remarkable cycling stability of 97% capacity retention after 182 cycles, and the average discharge potential drops only 90 mV in 100 cycles. In‐depth studies by electron energy loss spectroscopy and aberration‐corrected scanning transmission electron microscopy demonstrate the Li–Ti mixing structure. The charge compensation mechanism is uncovered with X‐ray absorption spectroscopy and explained with the density function theory calculations. These results show the superiority of introducing transition metal ions into the Li layers in reinforcing the structural stability of the Li‐rich layered metal oxides. These findings shed light on a possible path to the development of Li‐rich materials with better potential retention and a longer lifespan.     

脑肿瘤干细胞

脑肿瘤尤其是恶性脑胶质瘤,由于生长及复发快,预后极差,所以找到胶质瘤复发的根源,提高胶质瘤病人的存活率,已成为国内外的肿瘤生物学工作者和临床医学工作者亟待解决的难题。近年来肿瘤干细胞概念的提出及脑肿瘤干细胞的分离及鉴定,为脑肿瘤的研究提供了新的切入点,同时可成为肿瘤治疗新的靶标,为根治脑肿瘤带来了光明的前景。简要综述了脑肿瘤干细胞无限增殖、自我更新、多分化潜能的生物学特性,脑肿瘤干细胞的起源以及与脑肿瘤相关机制方面的研究进展,从而为今后脑肿瘤早期诊断、治疗以及以此为靶标的药物开发提供新的思路和方向。     

黄芪对镉致大鼠睾丸支持细胞超微结构及波形蛋白、E-钙粘蛋白表达改变的保护作用

目的 探讨黄芪对镉致大鼠睾丸支持细胞损伤的保护作用.方法 21只成年雄性SD大鼠随机分成镉组(0.1％氯化镉腹腔内注射,1mg/Kg体重/天,5天/周,处理后1、2、3、4周取材)、镉加黄芪组(注射氯化镉的同时注射黄芪,10g/Kg体重/天,5天/周,处理后2、4周取材)和对照组(腹腔内注射等量生理盐水).睾丸取材作光镜、免疫组织化学染色和图像分析及超微结构观察.结果 光镜H.E染色对照组支持细胞核不规则,染色浅,核仁明显,镉处理后胞浆内有空泡形成,镉加黄芪组支持细胞未见明显改变.对照组波形蛋白阳性产物在支持细胞靠近基室腔的胞浆中表达,E-钙粘蛋白阳性产物则主要定位于生精上皮近腔室的支持细胞和部分生精细胞胞浆中.镉处理后支持细胞胞浆中波形蛋白和E-钙粘蛋白阳性产物表达的平均光密度值均明显降低(P＜0.05),镉加黄芪组阳性产物表达虽较对照组减弱但明显高于相应镉组(P＜0.05).镉处理组支持细胞胞质特化区和紧密连接破坏,镉加黄芪组支持细胞超微病变较相应镉组为轻.结论 镉降低大鼠睾丸支持细胞波形蛋白和E-钙粘蛋白的表达并造成支持细胞的超微结构损伤,黄芪具有较好的保护效果.     

Evaluation of protocols used in 2-d electrophoresis for proteome analysis of young rice caryopsis

In order to obtain a high-resolution electrophorogram of rice young panicle proteome, we evaluated various protocols commonly used in two-dimensional (2D) polyacrylamide gel electrophoresis (PAGE) of proteins, including gel staining protocol, pH range of immobilized pH gradient (IPG) strips and sample loading quantity. Results showed that a silver staining protocol using sensitized solution containing glacial acetic acid, sodium acetate and sodium thiosulfate (reported by Heukeshoven and Dernick in 1988) and a Coomassie Brilliant Blue staining method using solution containing G-250, ammonium sulfate and phosphoric acid (reported by Pink et al in 2010) demonstrated the superior staining effect. In addition, we also showed that higher resolution was achieved when IPG gel strip with pH range of 5-8 was used, compared to that with pH range of 4-7. Finally, the optimal loading quantity was determined as 130 μg using the 17 cm-long nonlinear IPG strip with pH 5-8 in combination with the silver nitrate staining protocol. The evaluated results would be helpful in proteome analysis of young rice caryopsis.     

Dianyuea gen. nov. (Salicaceae: Scyphostegioideae) from southwestern China

Dianyuea C. Shang, S. Liao & Z. X. Zhang, a new monotypic genus of Salicaceae based on Flacourtia turbinata H. J. Dong & H. Peng, is described and illustrated. Morphologically, Dianyuea differs from Flacourtia Comm. ex L'Hér. by having six connate stamens, basal placentation and lobed seed appendages. All those features indicate that Dianyuea is allied with Scyphostegia Stapf. A molecular phylogenetic analysis using plastid trnL‐F, matK, and rbcL sequence data for representatives of 16 genera in Salicaceae s.l. shows that Dianyuea is sister to Scyphostegia. The new combination Dianyuea turbinata (H. J. Dong & H. Peng) C. Shang, S. Liao & Z. X. Zhang is proposed.     

Domain III from class II fusion proteins functions as a dominant-negative inhibitor of virus membrane fusion

Alphaviruses and flaviviruses infect cells through low pH-dependent membrane fusion reactions mediated by their structurally similar viral fusion proteins. During fusion, these class II viral fusion proteins trimerize and refold to form hairpin-like structures, with the domain III and stem regions folded back toward the target membrane-inserted fusion peptides. We demonstrate that exogenous domain III can function as a dominant-negative inhibitor of alphavirus and flavivirus membrane fusion and infection. Domain III binds stably to the fusion protein, thus preventing the foldback reaction and blocking the lipid mixing step of fusion. Our data reveal the existence of a relatively long-lived core trimer intermediate with which domain III interacts to initiate membrane fusion. These novel inhibitors of the class II fusion proteins show cross-inhibition within the virus genus and suggest that the domain III-core trimer interaction can serve as a new target for the development of antiviral reagents.     

Tenascin-R distinct domains modulate migration of neural stem/progenitor cells in vitro

Extracellular matrix (ECM) molecules constitute a "niche" that modulates the migration, proliferation, and differentiation of neural stem/progenitor cells (NSPCs). The glycoprotein Tenascin-R (TN-R) is an ECM molecule, comprising multiple domains. Either the whole TN-R molecule or its distinct domains has been demonstrated to play a very important role in the developing central nervous system. However, little is known about the effect of the TN-R domain on NSPCs, especially NSPC migration. In the present study, we first show that both TN-R domains epidermal growth factor-like repeat (EGFL) and fibronectin type III (FN)6-8 can inhibit the NSPCs migration from neurospheres in vitro. Furthermore, both the EGFL and FN6-8 domains affect the distribution of neurons generated from neurospheres, indicating that EGFL and FN6-8 domains inhibit the motility of neurons generated from neurospheres. These results suggest that TN-R has an inhibitory effect on NSPCs migration.     

高质量甘蔗基因组DNA的简便快速提取方法研究

甘蔗是世界上重要的糖料作物和能源作物。目前,甘蔗分子生物学研究已成为甘蔗研究的热点之一。基因组DNA的提取是进行甘蔗分子生物学研究的基础。本研究设计含一系列SDS浓度的提取液,同时设加液氮和不加液氮研磨的对比试验,提取甘蔗不同部位叶片的基因组DNA并进行产量和纯度检测以及分子生物学分析。结果表明,所有提取液提取的甘蔗基因组DNA纯度均很高,A260/A280在1.8-2.0之间,A260/A230大于2,但提取液I(0.75%SDS)提取的甘蔗基因组DNA产量较低;加液氮与否对甘蔗基因组DNA的提取产量和纯度没有影响;以提取的甘蔗基因组DNA为模板,分别用一对扩增SPS(蔗糖磷酸合成酶)基因部分片段的引物和一对ISSR引物进行PCR扩增,所有DNA均能扩增出预期的条带;用不同的限制性内切酶对所提取的甘蔗基因组DNA进行酶切,所有DNA样品均能完全酶切。本研究得出最佳甘蔗基因组DNA提取方法如下:磨碎甘蔗叶片后,加DNA提取液(SDS:1.5%;Tris:100 mM;EDTA:20 mM;NaCl:500 mM)于65℃裂解30 min,经酚∶氯仿和氯仿各抽提一次,可获得高产量高质量的甘蔗基因组DNA,能满足后续分子生物学研究的要求。