Structure of the human CLC-7/Ostm1 complex reveals a novel state

CLC-7 functions as a Cl?/H+ exchanger in lysosomes. Defects in CLC-7 and its β-subunit, Ostm1, result in osteopetrosis and neurodegeneration. Here, we present the cryogenic electron microscopy (cryo-EM) structure of the human CLC-7/Ostm1 complex (HsCLC-7/Ostm1) at a resolution of 3.6 ?. Our structure reveals a new state of the CLC-7/Ostm1 heterotetramer, in which the cytoplasmic domain of CLC-7 is absent, likely due to high flexibility. The disordered cytoplasmic domain is probably not able to restrain CLC-7 subunits and thus allow their relative movements. The movements result in an approximately half smaller interface between the CLC-7 transmembrane domains than that in a previously reported CLC-7/Ostm1 structure with a well-folded cytoplasmic domain. Key interactions involving multiple osteopetrosis-related residues are affected by the interface change.     

电子束熔化成形与锻造Ti6Al4V合金的腐蚀行为对比研究

本工作采用电化学工作站研究了电子束熔化技术（EBM）成形TC4样品和传统锻造TC4在3.5wt% NaCl溶液中的电化学腐蚀行为. 结果表明EBM成形TC4样品的非平衡微观结构使其与传统锻造的TC4相比,表现出不同的耐腐蚀性. EBM成形TC4样品与锻件TC4相比,EBM成形样品不同平面存在耐蚀性差异,而且EBM水平面大于锻件,EBM垂直面小于锻件. EBM成形TC4样品垂直面出现的腐蚀性能的各向异性主要是β柱状晶导致的. 在腐蚀的过程中,点蚀优先发生在α晶界,因为晶界能量较高,形成多孔的钝化层. 本项工作有助于丰富增材制造制备TC4合金在航空钛合金领域的腐蚀性能研究.     

基于PiggyBac转座系统的低溢漏诱导型Tet-On过表达体系的建立及应用

为避免诱导基因稳定表达的Tet-On诱导表达系统溢漏表达,实现简便且高效的外源基因稳定诱导表达, 本研究拟在Tet-On调控的转录水平基础上,将基于稳定配体Shield-1的不稳定结构域FK506结合蛋白引入目的基因的N端,从蛋白水平控制其本底表达水平.为验证该系统的效果,本研究以荧光蛋白TdTomato为报告基因,经流式分析结果证明优化后的体系较原体系的溢漏表达在蛋白水平上降低7倍左右.将该系统应用于基于小鼠胚胎干细胞的体外牙向分化模型,在诱导因子Dox和稳定配体Shield-1的协同作用下,诱导表达牙齿发育相关转录因子Hand2提高了牙向分化诱导的完成度.     

3—己烯—1—醇及其酯类的合成和香气研究

介绍了叶醇(cis-3-己烯-1-醇)及其异构体的实用合成路线。由顺反混合(或全反式)3-己烯-1-醇制备了一系列羧酸酯,研究了这些化合物的结构与香气的关系,从中发现一些有实用价值的新香料。     

苯甲酰三氟丙酮与稀土配合物的合成及性质研究

本文合成了苯甲酰三氟丙酮（Ｌ）和三苯基氧膦（ＴＰＰＯ）、联吡啶（Ｂｉｐｙ）、邻菲罗啉（ｐｈｅｎ）、四甲基氢化铵（ＮＭｅ４ＯＨ）与稀土Ｙ、Ｌａ、Ｅｕ、Ｔｂ离子的混合型配合物。测定配合物的Ｈ１ＮＭＲ谱及质谱,并对测定结果进行了分析。     

含双二苯基膦戊烷铜(Ⅰ)配合物的合成与性质

室温,氮气氛下,铜（Ⅱ）盐和双二苯基膦戊烷（ｄｐｐｐ５）在溶液中通过还原取代反应合成了８种铜（Ⅰ）配合物（１．［Ｃｕ（ｄｐｐｐ５）］２（ＢＦ４）２,２．［Ｃｕ２（ｄｐｐｐ５）２（Ｃ８Ｈ３Ｏ２ＳＦ３）２］,３．［Ｃｕ２（ｄｐｐｐ５）３］（ＣＣｌ３ＣＯＯ）２,４．［ＣｕＢｒ（ｄｐｐｐ５）］２,５．［Ｃｕ２（ｄｐｐｐ５）Ｃｌ２］,６．［Ｃｕ２（ｄｐｐｐ５）３］（ＣＨ３ＣＯＯ）２,７．［Ｃｕ（ｄｐｐｐ５）（ＮＯ３）］,８．［Ｃｕ２（ｄｐｐｐ５）３］（ＣｌＯ４）２）。通过元素分析、红外光谱、热重、摩尔电导测定对其进行表征,表明这是一种行之有效的有机膦配合物的合成方法。     

阳离子交换树脂催化合成1—萘乙酸甲酯的研究

本文研究了用强酸性阳离子交换树脂作催化剂,１—萘乙酸和甲醇直接酯化合成１—萘乙酸甲酯的反应。考察了催化剂用量,反应物料配比,反应时间等因素对产率的影响,通过正交实验,找到了较佳反应条件：当催化剂用量为反应液的３％,醇酸摩尔比为２０～３０,在回流温度下反应４小时,酯的收率＞９２％,纯度＞９９％。该法工艺简单,操作方便,无三废污染,适合工业化生产。     

1,6—二磷酸果糖制备研究：Ⅰ.菌种的筛选及培养条件

介绍了１,６－二磷酸果糖产生菌的筛选和最佳培养条件的确定,在所筛选的菌种中９５１８、９５１９号菌株均具较高的产１,６－二磷酸果糖酶系活力。其最佳培养条件为：培养温度２８℃,ｐＨ６．５。     

Preparation and optical properties of solid solution semiconductor (Zn x Cd1−x S) doped silica glasses

Semiconductor(Zn_xCd_1−x S) doped silica glasses were prepared by Sol-Gel process andin situ growth technique. The structure of the materials was characterized by X-ray diffraction technique, the particle size of semiconductor crystallites from X-ray patterns was estimated less than 10 nm. From absorption spectra, it is obtained that the absorption edges shifted to short wavelength direction when Zn contents increased, and the absorption edge can be adjusted from 2.46 eV to 2.96 eV by controlling Zn contents. The third-order nonlinear optical susceptibility was studied at 532 nm with 8 ns pulse laser by degenerate four wave mixing (DFWM) technique.     

Signal transduction pathways mediated by colony stimulating factor-1 receptor

Colony-stimulating factor-1 (CSF-1), which is necessary for cell proliferation and differentiation, regulates both immediate and delayed early responses throughout G1 phase. The binding of CSF-1 to its receptor (CSF-1R) triggers phosphorylation of the receptor and its intrinsic tyrosine kinase. The activated receptor binds directly to cytoplasmic effector proteins, which induce multiple-signal transduction pathways. CSF-1 can induce the c-myc gene expression via Ras and Ets-related proteins. The expression of c-fos/jun family genes is also targeted following the activation of Ras. CSF-1R activates STAT1 and STAT3 to participate in signaling, but JAKs do not appear to contribute to signaling by CSF-1R. CSF-1R activates PI3-kinase, and PI3-ki can interact with downstream proteins by the MAPKK-related pathway independent of Ras/Raf. PC-PLC can enforce signaling in response to CSF-1. Furthermore, the turnover and dephosphorylation by the phosphatase SHPTP1 of CSF-1R are the major mechanism in the negative regulation of signaling by CSF-1R