Structural polymorphism of human telomere G-quadruplex induced by a pyridyl carboxamide molecule

In this work, we described a kinetically slow (hour-scale) but thermodynamically favored G-quadruplex conversion induced by a pyridyl carboxamide molecule. This slow transition was observed through CD spectra and gels, and its final stable parallel conformation was identified by 2-aminopurine experiments. Kinetic experiments indicated that this slow process was a first-order reaction, implying it was a unimolecular conversion. Quite distinctly from other reported ligand-driven G-quadruplex conformation alteration, this slow conversion reveals a novel insight into G-quadruplex polymorphism, in accordance with the behavior of human telomere G-quadruplex in a molecular crowding environment in K(+) solution, further enriching the known structural polymorphism of human telomere DNA and providing new consideration for drug design based on G-quadruplexes.     

Methylation effects on the microdomain structures of phosphatidylethanolamine monolayers.

Increasing methylation of the headgroup in DPPE results in an increase of minimum area per molecule in highly compressed monolayers at the air-water interface. The shape of solid domains, as observed by epifluorescence microscopy, also exhibits marked changes upon increasing headgroup methylation. Branching domains are observed in DPPE and DP(Me)PE, whereas U-shaped or round domains are observed in DP(Me)2PE and DPPC under our experimental conditions. The domain shape is determined more by the headgroup methylatin than by the corresponding shift in critical temperatures, as shown by the study of PCs of different acyl chain moieties. In mixed lipid monolayers, PC (phosphatidylcholine) and PE (phosphatidylethanolamine) do not mix ideally, as indicated by the non-linear variation of the average area per molecule with composition, and by distinct domain shapes in LE/LC (liquid expanded/liquid condensed) coexisting phases representing PE-enriched or PC-enriched domains in those mixed monolayers.     

竹叶菜的组织培养研究

竹叶菜为百合科鹿药属一种多年生草本植物,因做菜口感好,且营养丰富、药用价值高而成为深受人们喜爱的一种野生蔬菜.有关竹叶菜及其同属的组织培养研究均未见报道.本文以竹叶菜的顶芽为外植体,通过器官发生途径,初步探索了竹叶菜的组织培养技术,结果表明:芽诱导的合适培养基为:MS +6-BA 1.5 +NAA 0.05+0.6％琼脂+3％蔗糖;芽继代培养的合适培养基为:MS+6-BA 1.2 +NAA 0.05 +0.6％琼脂+3％蔗糖;无菌小苗生根的合适培养基为:MS+ IAA 1.5+ NAA 0.2+ 0.6％琼脂+3％蔗糖.为竹叶菜今后较大规模地栽培或生产提供种苗及技术贮备,为实现竹叶菜资源的可持续性开发利用奠定了基础.     

诺如病毒GII.6 P粒子原核表达与纯化

原核表达的诺如病毒(Noroviruses,NoV)衣壳蛋白亚基P粒子与No V有相同的抗原类型,可以代替NoV在体外进行结合,这对于研究该病毒与宿主和环境载体结合的相关机理有重大意义。本研究成功构建GII.6 P粒子基因表达载体,并对原核表达体系中诱导剂浓度、诱导温度及诱导时间进行优化。结果表明表达载体在22℃、2×10~(-4)mol/L IPTG诱导22 h后表达量最高。随后,在亲和层析的基础上结合阴离子交换以及凝胶过滤层析对表达产物进行纯化,最终获得高纯度GII.6 P粒子。     

硝尔库勒湖可培养放线菌多样性及其功能酶和抗细菌活性

【目的】认识和了解硝尔库勒湖可培养放线菌的多样性、功能酶和抗细菌活性特点,为今后的开发和利用奠定基础。【方法】应用可培养技术和基于16S r RNA基因序列的系统发育分析硝尔库勒盐湖沉积物中放线菌的多样性。常规方法检测样品成分因子,并筛选了嗜盐放线菌的蛋白酶、淀粉酶和酯酶活性;抑菌圈法检测放线菌新种的抗细菌活性。【结果】分离获得了51个OTUs,分属于24个不同的属,其中15个OTUs代表了放线菌新种;链霉菌属是优势菌属,占全部分离菌株数量的16.25%。硝尔库勒湖放线菌类群数量一定程度上受样品成分因子的协同影响。代表新种的菌株展示了良好的功能酶活性和抗细菌活性,其中代表链霉菌新种的菌株XHU5011不仅具有多种酶活性,而且具有强大的抗金黄葡萄球菌、耻垢分枝杆菌和荧光假单胞菌的能力,具有很好的开发潜能。【结论】硝尔库勒盐湖中存在丰富的可培养放线菌多样性,潜藏着大量的放线菌新资源,并且具有很好的功能酶和天然产物挖掘潜力。     

Effects of a dark-septate endophytic isolate LBF-2 on the medicinal plant <Emphasis Type="Italic">Lycium barbarum</Emphasis> L.

Dark septate endophytes (DSE) are ubiquitous root associated fungi; however, our understanding of their ecological function remains unclear. Here, we investigated the positive effect of a DSE fungus on its host plant Lycium barbarum L. A DSE isolate, LBF-2, isolated from the roots of L. barbarum, was inoculated onto the roots of plants, which were grown under greenhouse conditions for five weeks. The result of molecular analyses of internal transcribed spacer regions indicated that LBF-2 was 96% similar to Paraphoma chrysanthemicola. Melanized septate hyphae were observed in the root cortical cells of L. barbarum using a light microscope. Inoculation with LBF-2 increased the total biomass by 39.2% and also enhanced chlorophyll fluorescence. Inoculation increased the concentration of total chlorophyll by 22.8% and of chlorophyll a by 21.3%, relative to uninoculated controls. These data indicate that the LBF-2 isolate might be used to facilitate the cultivation of L. barbarum, which has medicinal applications.     

Design of high performance nanozymes: a single-atom strategy

<正>Nanozymes, nanomaterials with enzyme-like characteristics,are emerging as novel artificial enzymes (Gao et al., 2007;Manea et al., 2004; Yan, 2018). They are superior to natural enzymes in many ways, such as higher stability, lower cost in preparation, and better robustness toward harsh environments (Wei and Wang, 2013). Various nanomaterials (e.g.,     

干旱区不同地理种群骆驼刺元素组成及表面结构特征的对比研究

碳(C)、氮(N)、磷(P)元素在植物各器官中的组成,及植物表面结构差异是其对外界环境适应性的重要表征。以干旱区3个地理种群骆驼刺(塔里木盆地策勒种群,吐鄯托盆地托克逊种群,准噶尔盆地阜康种群)为研究对象,通过对植株各器官C,N,P元素组成的测定及表面形貌观测,对其在不同环境中的适应特性进行了比较研究。结果表明:(1)同一种群的骆驼刺,C元素在各器官中的分配没有显著规律;N元素在叶片中含量最高,茎中最低;策勒种群和阜康种群的P含量,叶片中最高,茎与刺中差异不显著;但托克逊种群茎中P含量显著高于其他部位。(2)3个地理种群的骆驼刺叶中元素组成相比,策勒种群C,N含量均最高,托克逊种群C,N含量最低;3个种群叶片的P含量,C∶N,C∶P,N∶P值均没有显著差异。刺中元素含量相比,C含量没有显著差异;N含量阜康种群策勒种群托克逊种群。茎中元素含量相比,N含量差异不显著,但托克逊种群茎中P含量为其他两个种群的2倍,可能与托克逊土壤中高浓度的全N,速效N,速效P有关。(3)托克逊种群表皮极厚,蜡质非常致密,各器官气孔密度均高于其他两个种群;策勒种群比阜康种群叶表皮增厚,蜡质致密,但叶片气孔密度却减小;策勒种群和阜康种群茎与刺的气孔密度差异不显著。研究表明,策勒种群骆驼刺最适应当地环境条件:其叶片具有最高的C,N含量,且表面结构没有明显的干旱胁迫特征。托克逊种群表现出明显的干旱适应特征:其表皮增厚,蜡质致密,气孔密度增大,叶片C,N含量最低。虽然托克逊种群茎中P含量显著高于其他地理种群,但3个地理种群骆驼刺叶片中C∶N,C∶P,N∶P比值保持恒定,C∶N=30.6±4.3,C∶P=357.4±49.9,N∶P=12.0±2.4,说明骆驼刺能够保持较高内稳性,这也可能是其在新疆各地广泛生存的重要原因。