藏区金腰种质资源调查与分析

金腰属植物因富含黄酮醇类化合物而具有显著的药效,通过对我国西藏、云南、四川、青海以及甘肃5个省(自治区)进行金腰属植物种质资源的科学考察,共收集到19种(含2变种)145份野生种质资源。此外四川省发现金腰新分布2种,分别为秦岭金腰(Chrysosplenium biondianum Engl.)、陕甘金腰(Chrysosplenium qinlingense Z.P.Jien&J.T.Pan),均为中国特有种;甘肃省发现金腰新分布3种,分别为毛金腰(Chrysosplenium pilosum Maxim.)、绵毛金腰(Chrysosplenium lanuginosum Hook.f.&Thomson)和蜕叶金腰(Chrysosplenium henryi Franch.),凭证标本存于中南民族大学植物标本馆(HSN)。金腰属植物作为传统藏药长期以来被用于治疗各种疾病,如长梗金腰(Chrysosplenium axillare Maxim.)的75%乙醇提取物具抗炎症、抗流感病毒活性,从灰花金腰(Chrysosplenium grayanum Maxim.)与裸茎金腰(Chrysosplenium nudicaule Bunge)提取的五环三萜对肿瘤细胞有较强抑制效果。本调查丰富了野生藏药金腰属植物种质资源,为深入研究金腰属植物的分类与药理活性提供了基础。     

基于计算流体力学数值模拟的城市绿地温湿效应及室外热舒适评价研究进展

近年来随着计算机与各学科领域交叉研究的发展,计算流体力学数值模拟方法在城市环境的微气候研究方面得到较多应用,为研究绿地在有限面积内更有效地实现其降温效应提供了新的思路。回顾计算流体力学（CFD）数值模拟方法在不同尺度的城市绿地温湿效应及室外热舒适度评价研究中的应用,在此基础上,总结目前存在的问题及不足,对未来该领域的研究方向提出3点展望,以期为未来城市绿地微气候研究提供参考：1）多平台与尺度扩展研究;2）微气候特征指标的综合交叉分析;3）高适配度模拟模型的及时更新。     

覆膜支架腔内修复术与药物保守治疗对Stanford B型主动脉夹层动脉瘤患者肝肾功能、炎性因子以及预后的影响

目的:比较覆膜支架腔内修复术与药物保守治疗对Standford B型主动脉夹层动脉瘤的疗效及对患者肝肾功能、炎性因子及预后的影响。方法:选择2012年1月～2014年8月我院收治的Standford B型主动脉夹层动脉瘤患者68例,按照随机数字表法分为对照组与研究组,各34例。对照组入院后采取药物保守治疗,研究组应用覆膜支架腔内修复术治疗。观察两组住院期间死亡率、再次手术或介入率以及治疗前、治疗2周后肝肾功能、血清炎性因子变化。所有患者随访36个月,比较两组患者预后情况。结果:研究组再次手术或介入率为2.94%,低于对照组的22.58%(P0.05)。治疗2周后,研究组丙氨酸转氨酶(ALT)、天门冬氨酸氨基转移酶(AST)、尿素氮(BUN)、肌酐(Cr)、胱抑素C、肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)、γ-干扰素(INF-γ)、C反应蛋白(CRP)水平较治疗前降低(P0.05),且研究组低于对照组(P0.05)。两组患者均随访36个月,随访12个月时两组患者生存率分别为100.00%和80.65%,随访36个月时两组患者生存率分别为91.18%和29.03%,经Log Rank分析显示,两组生存率比较差异有统计学意义(P0.05)。结论:覆膜支架腔内修复术治疗Standford B型主动脉夹层动脉瘤的疗效确切,能够改善患者肝肾功能,降低炎症反应,患者近中期随访生存率较高,其效果优于保守治疗。     

肺脏超声对新生儿呼吸窘迫综合征的诊断价值及肺超声评分的评估价值分析

目的:探讨肺脏超声对新生儿呼吸窘迫综合征(NRDS)的诊断价值,并分析肺超声评分的临床应用价值。方法:本研究选择2017年5月至2018年5月于我院确诊的NRDS患儿45例作为观察组,选择同期于我院就诊的非肺病患儿45例作为对照组,所有患儿均行肺脏超声检查。分析NRDS患儿肺脏超声特征性征象,比较肺脏超声对两组患儿各种征象的检出率,分析肺脏超声对NRDS的诊断价值,比较两组肺超声评分。结果:NRDS患儿全部存在肺实质征象,超声下肺组织回声呈肝样伴支气管充气征,轻度的NRDS患儿于肺脏超声下表现为局灶性的肺实质,且支气管充气征不明显;重度的NRDS患儿于肺脏超声下表现为肺实质范围的进一步扩大,且支气管充气征随病情的加重而愈发明显。观察组肺实质、胸膜线异常、A线消失、弥漫性肺水肿、支气管充气征等征象的检出率显著高于对照组(P0.05),两组B线存在征象的检出率比较无统计学差异(P0.05)。肺实质、胸膜线异常和A线消失三种特征征象同时存在时对NRDS诊断的灵敏度和特异性均为100.00%,肺实质、胸膜线异常和支气管充气征三种特征征象同时存在时对NRDS诊断的灵敏度为80.00%,特异性为100.00%。观察组双肺、左肺、右肺、双侧肺、双肺底肺超声评分均高于对照组(P0.05)。结论:肺脏超声对NRDS的诊断价值较高,且肺超声评分可以评估NRDS患儿的病情严重程度,有助于指导患儿的治疗。     

Covalent vs. Non‐Covalent Inhibition: Tackling Drug Resistance in EGFR – A Thorough Dynamic Perspective

A persistent challenge in the treatment of non‐small cell lung cancer (NSCLC) with EGFR is the emergence of drug‐resistant caused by somatic mutations. The EGFR L858R/T790 M double mutant (EGFR^DM) was found to be the most alarming variant. Despite the development of a wide range of inhibitors, none of them could inhibit EGFR^DM effectively. Recently, 11h and 45a , have been found to be potent inhibitors against EGFR^DM through two distinctive mechanisms, non‐covalent and covalent binding, respectively. However, the structural and dynamic implications of the two modes of inhibitions remain unexplored. Herein, two molecular dynamics simulation protocols, coupled with free‐energy calculations, were applied to gain insight into the atomistic nature of each binding mode. The comparative analysis confirmed that there is a significant difference in the binding free energy between 11h and 45a (ΔΔG_bind=?21.17 kcal/mol). The main binding force that governs the binding of both inhibitors is vdW, with a higher contribution for 45a . Two residues ARG841 and THR854 were found to have curtailed role in the binding of 45a to EGFR^DM by stabilizing its flexible alcohol chain. The 45a binding to EGFR^DM induces structural rearrangement in the active site to allow easier accessibility of 45a to target residue CYS797. The findings of this work can substantially shed light on new strategies for developing novel classes of covalent and non‐covalent inhibitors with increased specificity and potency.     

Proto-dolomite formation in microbial consortia dominated by Halomonas strains

Extremophiles - Microbes can be found in hypersaline environments forming diverse populations with complex ecological interactions. Microbes in such environments were found to be involved in the...     

Nanocomposite scaffold seeded with mesenchymal stem cells for bone repair

The mechanical property of bone tissue scaffolds is one of the most important aspects in bone tissue engineering that has remained problematic. In our previous study, we fabricated a three‐dimensional scaffold from nano‐hydroxyapatite/gelatin (nHA/Gel) and investigated its efficiency in promoting bone regeneration both in vitro and in vivo. In the present study, the effect of adding silicon carbide (SiC) on the mechanical and biological behaviors of the nHA/Gel/SiC and bone regeneration in vivo were determined. nHA and SiC were synthesized and characterized by the X‐ray diffraction pattern and transmission electron microscope image. Layer solvent casting, freeze drying, and lamination techniques were applied to prepare these scaffolds. Then, the biocompatibility and cell adhesion behavior of the synthesized nHA/Gel/SiC scaffolds were investigated. For in vivo studies, rats were categorized into three groups: blank defect, blank scaffold, and rat bone marrow mesenchymal stem cells (rBM‐MSCs)/scaffold. After 1, 4, and 12 weeks post‐injury, the rats were sacrificed and the calvaria were harvested. Sections with a thickness of 5 µm thickness were prepared and stained with hematoxylin–eosin and Masson's Trichrome, and immunohistochemistry was performed. Our results showed that SiC effectively increased the mechanical properties of the nHA/Gel/SiC scaffold. No significant differences were observed in biocompatibility, cell adhesion, and cytotoxicity of the nHA/Gel/SiC in comparison with the nHA/Gel nanocomposite. Based on histological and immunohistochemical studies, both osteogenesis and collagenization were significantly higher in the rBM‐MSCs/scaffold group, quantitatively and qualitatively. The present study strongly suggests the potential of SiC as an alternative strategy to improve the mechanical and biological properties of bone tissue engineering scaffolds, and shows that the pre‐seeded nHA/Gel/SiC scaffold with rBM‐MSCs improves osteogenesis in the engineered bone implant.     

中国东部沿海水仙归化群体的遗传多样性

为揭示我国东部归化水仙(Narcissus tazetta var. chinensis)的群体遗传多样性,利用2个叶绿体基因mat K和trn H-psb A片段对采自沪、浙、闽的5个代表群体的49株水仙进行了评估。结果表明,双基因联合序列的总长为1443bp,共定义6个单倍型,各归化群体的遗传多样性水平为DLSYPTDNJD=ZZCMD。AMOVA分析表明,群体内变异为遗传变异的主要来源(91.98%),群体间的遗传分化较低(Fst=0.080 22)。群体物种水平上的谱系结构不显著(Nst=0.020Gst=0.031;P0.05)。Mantel检验表明水仙群体间的遗传距离与地理距离呈显著的线性相关(r=0.929,P=0.02 0.05)。中性检验和错配分布分析结果均暗示水仙群体背离了快速扩张模型的假设。单倍型分布的中介网络图结合系统发育NJ树均将所有群体划分为2大分支。因此,我国东部沿海水仙归化群体整体遗传多样性水平较低,各群体间遗传分化较弱,遗传变异主要来自群体内,物种近期未经历扩张事件,可能是基因流受海岛隔离、自身生物学特征、生境异质性与及人为干扰的综合作用影响。     

microRNA在结核分枝杆菌抗细胞自噬作用中的研究进展

结核分枝杆菌(Mycobacteria tuberculosis,MTB)是结核病的致病菌,其感染机体后能在细胞内长期生存并在合适的条件下引发疾病.非氧依赖性杀伤是巨噬细胞清除MTB的重要途径,主要表现为细胞内吞体和溶酶体融合,利用细胞自噬作用清除内部细菌.相应的,MTB可利用多种方式顽强抵抗细胞自噬作用,与细胞共存从而逃避宿主免疫杀伤作用. MicroRNA(miRNA)是一种内源性非编码单链小RNA分子,其能在转录后水平沉默相关基因表达,是介导MTB与炎性细胞许多反应的重要分子.近期研究发现,MTB能够通过诱导巨噬细胞特异表达一些miRNA分子并靶向自噬相关基因,阻碍自噬发生、发展,从而实现MTB的抗细胞自噬作用.本文就miRNA在MTB抗细胞自噬中的作用及机制的研究进展作一综述.     

人二氢乳清酸脱氢酶蛋白的表达、纯化及其与新型抑制剂的晶体结构

人二氢乳清酸脱氢酶（human dihydroorotate dehydrogenase, hDHODH）是催化嘧啶从头合成途径的一个关键酶。近年来,多种研究表明,抑制该酶可缓解类风湿性关节炎的症状。但该酶的抑制剂甚少,寻找该酶的高效抑制剂具有重要意义。本研究利用PCR技术扩增hDHODH基因,构建重组质粒pET-19b-hDHODH,并在大肠杆菌(Escherichia coli, E.coli ) BL21(DE3)中表达,获得可溶性蛋白质。用Ni2+-NTA亲和层析柱对蛋白质进行纯化,获得较高（90%）纯度的hDHODH蛋白,将蛋白质与抑制剂3-(5-乙硫基)-1H-1, 2, 4-三氮唑-3-)苯甲酸和底物DHO混合孵育。用Hampton试剂盒初筛晶体并用棋盘法进行优化,获得晶形完美、衍射能力很强的hDHODH蛋白复合物单晶。用X射线衍射晶体,用CCP4、Coot软件解析结构,获得hDHODH蛋白复合物晶体结构。从解析的结构中可以看出,抑制剂与蛋白质的吻合度非常高,且抑制剂通过亲水的羧基端与蛋白质356位和147位的酪氨酸形成氢键网络。抑制剂的5元环与蛋白质359位的亮氨酸和360位的苏氨酸相互作用,使抑制剂与蛋白质牢固结合。该复合物晶体结构的顺利解析,将为开发新型特异性抗类风湿性关节炎药物提供重要基础。