Solution structure of the N‐terminal domain of DC‐UbP/UBTD2 and its interaction with ubiquitin

DC‐UbP/UBTD2 is a ubiquitin (Ub) domain‐containing protein first identified from dendritic cells, and is implicated in ubiquitination pathway. The solution structure and backbone dynamics of the C‐terminal Ub‐like (UbL) domain were elucidated in our previous work. To further understand the biological function of DC‐UbP, we then solved the solution structure of the N‐terminal domain of DC‐UbP (DC‐UbP_N) and studied its Ub binding properties by NMR techniques. The results show that DC‐UbP_N holds a novel structural fold and acts as a Ub‐binding domain (UBD) but with low affinity. This implies that the DC‐UbP protein, composing of a combination of both UbL and UBD domains, might play an important role in regulating protein ubiquitination and delivery of ubiquitinated substrates in eukaryotic cells.     

Human pDCs Are Superior to cDC2s in Attracting Cytolytic Lymphocytes in Melanoma Patients Receiving DC Vaccination

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藤椒精油对腐败解淀粉芽孢杆菌DY1a生物被膜的抑制作用

【背景】芽孢杆菌是豆制品的重要腐败菌,在气液界面形成生物膜,对产品生产带来持续污染。【目的】探讨藤椒精油(Zanthoxylum armatum DC.essential oil,ZA-EO)对腐败解淀粉芽孢杆菌DY1a菌体及生物被膜的抑制作用与机制。【方法】采用气相色谱-质谱(gas chromatography-mass spectrometer,GC-MS)分析藤椒精油主要成分与相对含量,通过二倍稀释法测定藤椒精油对菌株的最低抑菌浓度(minimum inhibitory concentration,MIC)和最低杀菌浓度(minimum bactericidal concentration,MBC),并分析精油对腐败菌胞外蛋白酶活性、腐败菌生物被膜形成抑制及成熟生物被膜的清除作用,采用扫描电镜结合三维光学显微镜分析生物被膜形貌结构变化,测定生物被膜胞外聚合物(extracellular polymeric substance,EPS)多糖与蛋白质含量变化;并通过细菌运动能力、细胞黏附及自聚集能力、细胞表面疏水性和Zeta电位来初步探讨藤椒精油对生物被膜的抑制机理。【结果】藤椒精...     

艾纳香内生真菌Diaporthe sp.次生代谢产物

【目的】从艾纳香内生菌J1中获得活性次生代谢产物。【方法】对菌株J1进行ITS序列分子鉴定,综合运用多种色谱技术对其发酵产物进行分离纯化,结合波谱学技术对其进行结构表征。【结果】经构建系统进化树,鉴定菌株J1为Diaporthe sp.,从该菌株大米培养基中分离得到7个单体化合物,经鉴定分别为Dicerandrol A (1)、Dicerandrol B (2)、4,6-dihydroxy-1H-isoindole1,3(2H)-dione (3)、Cytochalasin H (4)、Cytochalasin J (5)、4,6-dihydroxy-2,3-dihydro-1H-isoindol-1-one (6)、Cerebroside C (7)。所有化合物均为首次从该菌中分得,化合物1对枯草芽孢杆菌Bacillus subtilis KCTC 1021具有非常强的抑制活性,MIC值为0.125μg/mL。【结论】Diaporthe sp.富含抑菌活性化合物,具有开发成微生物源农药潜力。     

药用植物富贵菜的研究现状与展望

富贵菜(Gynura divaricata DC.)是中国民间传统的药食兼用型多年生草本植物资源,具有清热、凉血、止痛、调节免疫、降血糖和抗肿瘤的功效。对富贵菜国内外研究进展进行了综述,内容涉及植物学特性、生态学特性、营养与保健、采后保鲜、栽培繁殖病虫害防治、功能化学成分及药理作用研究等方面。并在对其所存在的问题进行初步讨论的基础上,提出在加强种植资源遗传多样性研究与保护的同时,开展现在育种技术和栽培技术的研究,结合新兴生物技术和药理研究,开展富贵菜资源的综合运用。     

HLA-Ig Based Artificial Antigen Presenting Cells for Efficient ex vivo Expansion of Human CTL

CTL with optimal effector function play critical roles in mediating protection against various intracellular infections and cancer. However, individuals may exhibit suppressive immune microenvironment and, in contrast to activating CTL, their autologous antigen presenting cells may tend to tolerize or anergize antigen specific CTL. As a result, although still in the experimental phase, CTL-based adoptive immunotherapy has evolved to become a promising treatment for various diseases such as cancer and virus infections. In initial experiments ex vivo expanded CMV (cytomegalovirus) specific CTL have been used for treatment of CMV infection in immunocompromised allogeneic bone marrow transplant patients. While it is common to have life-threatening CMV viremia in these patients, none of the patients receiving expanded CTL develop CMV related illness, implying the anti-CMV immunity is established by the adoptively transferred CTL¹. Promising results have also been observed for melanoma and may be extended to other types of cancer². While there are many ways to ex vivo stimulate and expand human CTL, current approaches are restricted by the cost and technical limitations. For example, the current gold standard is based on the use of autologous DC. This requires each patient to donate a significant number of leukocytes and is also very expensive and laborious. Moreover, detailed in vitro characterization of DC expanded CTL has revealed that these have only suboptimal effector function ³. Here we present a highly efficient aAPC based system for ex vivo expansion of human CMV specific CTL for adoptive immunotherapy (Figure 1). The aAPC were made by coupling cell sized magnetic beads with human HLA-A2-Ig dimer and anti-CD28mAb⁴. Once aAPC are made, they can be loaded with various peptides of interest, and remain functional for months. In this report, aAPC were loaded with a dominant peptide from CMV, pp65 (NLVPMVATV). After culturing purified human CD8⁺ CTL from a healthy donor with aAPC for one week, CMV specific CTL can be increased dramatically in specificity up to 98% (Figure 2) and amplified more than 10,000 fold. If more CMV-specific CTL are required, further expansion can be easily achieved by repetitive stimulation with aAPC. Phenotypic and functional characterization shows these expanded cells have an effector-memory phenotype and make significant amounts of both TNFα and IFNγ (Figure 3).     

病原菌Pst DC3000侵染拟南芥导致自噬和光合作用的抑制

在病原菌侵染下,植物体是如何通过超敏反应限制病原菌扩增的,到目前为止还不清楚。最近的研究显示自噬起了必要的作用,可见,研究自噬和超敏反应的机制非常重要。本研究通过观察在非寄主病原菌突变体丁香假单胞菌番茄致病变种(Pseudomonas syringae pv.tomatoDC3000,Pst DC3000)的侵染下,拟南芥光合功能的变化及自噬现象出现的情况,以为进一步研究植物抗病机理提供实验基础。以野生型拟南芥为材料,采用光谱分析和叶绿素荧光成像分析手段,研究不同浓度的Pst DC3000侵染对拟南芥离体叶片光合功能的影响;以转基因野生型拟南芥(绿色荧光蛋白标记的自噬基因8a)幼根为材料,应用共聚焦显微镜,研究不同浓度的Pst DC3000诱导拟南芥自噬的情况。实验发现,OD600=0.2的Pst DC3000侵染,可显著诱导拟南芥叶片活性氧的积累和迸发,并会引起拟南芥叶片光合作用效率的下降。同时发现,该病原菌处理2 h,可导致拟南芥根中自噬小体的产生。用2',7'-二氯二氢荧光素二乙酯(2',7'-dichlorodihydrofluorescein diacetate,H2DCFDA)标记活性氧,检测了P...     

细叶百合LpPEX7基因克隆及盐胁迫下的表达特性分析

从细叶百合的鳞茎中克隆出过氧化物酶体生物合成蛋白基因（LpPEX7）,该基因ORF全长957 bp,编码318个氨基酸。LpPEX7蛋白序列包含6个WD40保守结构域,通过同源蛋白序列比对和进化树分析,发现LpPEX7与其他植物的PEX7蛋白具有较高的同源性。LpPEX7基因在细叶百合种子,叶片和鳞茎中的表达量比较高,在根和花中表达量比较低,在H₂O₂,NaCl,NaHCO₃不同逆境处理条件下,LpPEX7基因的表达量都发生了改变。在盐碱和氧化胁迫处理下,LpPEX7过表达拟南芥株系种子的萌发要早于野生型种子的萌发,这些研究结果表明LpPEX7基因与盐碱、氧化逆境有一定的应答关系,为细叶百合的耐盐碱性分子机理研究提供一个非常重要的候选基因。     

高通量测序分析重庆地区茅苍术根际丛枝菌根真菌多样性

【背景】丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)是土壤微生物区系中分布最广泛的一类菌根真菌,能与地球上90%的维管植物形成共生体,可通过调节植物的生理代谢过程增强植物的抗逆性。【目的】揭示重庆地区中药材茅苍术根际土壤中AMF的结构与组成,解析土壤因子对AMF类群的影响。【方法】以重庆地区茅苍术主产地彭水县、秀山县、石柱县、南川区和酉阳县2-3年生茅苍术根际土壤为材料,利用Illumina MiSeq 2500测序平台进行真菌扩增子测序,分析不同地点土壤的茅苍术根际AMF类群组成和多样性的差异。【结果】茅苍术的菌根侵染率均在50%以上,每10g风干土壤中孢子含量在50个以上,最高达到144个。根际土壤共检测到球囊菌门Glomeromycota的3纲4目8科9属AMF,包括Glomus、Claroideoglomus、Gigaspora、Paraglomus、Archaeospora、Ambispora、Acaulospora、Diversispora和Scutellospora,其中前6属为5个区县土样共有。球囊霉属(Glomus)相对丰度最高,达67%,为所有地区茅苍术根际样本中的优势类群。冗余度分析(redundancy analysis,RDA)表明,土壤pH对AMF群落组成影响最大。pH、有机质、碱解氮、速效钾与Shannon指数呈正相关,有效磷与之呈负相关;各土壤因子与Simpson指数的相关性则相反。5个土壤因子均与丰度(Chao1)指数呈负相关。另外,pH、有机质与均匀度(ACE)指数呈正相关;碱解氮、速效钾、有效磷与之呈负相关。【结论】茅苍术根际土壤中AMF资源丰富,土壤因子对AMF群落组成和丰度影响显著,是导致AMF群落结构地理分布格局差异的重要原因之一。