药用霍山石斛原球茎的液体悬浮培养

目的:考察霍山石斛原球茎在液体培养中增殖、水溶性多糖与总生物碱积累的特征。方法:在霍山石斛试管苗茎段原球茎诱导与继代培养的基础上,进行原球茎的液体悬浮培养,分析原球茎生长动态,用比色法测定水溶性多糖与总生物碱的含量。结果:霍山石斛茎段在NAA或NAA与KT组合的MS培养基上可诱导出原球茎,MS基本培养基最适合原球茎继代培养增殖;原球茎在液体悬浮培养中最大比生长速率0.044·d^-1,倍增时间15.8 d,最适生长周期为4周,水溶性多糖和总生物碱含量分别是3.75％和0.0261％。结论:霍山石斛原球茎液体培养生长良好,具有目的化学成分的合成能力,为发酵培养开发霍山石斛资源提供可能。     

怀槐愈伤组织形成与异黄酮积累

目的 :考察怀槐愈伤组织形成与总异黄酮积累的关系。方法 :不同培养基诱导怀槐子叶和下胚轴产生愈伤组织 ,紫外分光光度术测定愈伤组织中总异黄酮并含量。结果 :NAA /BA及含 2 ,4-D组合有利子叶愈伤组织的诱导 ;MS ,N6 ,B5培养基适宜子叶形成愈伤组织 ,而SH较适宜下胚轴产生愈伤组织。愈伤组织具有异黄酮合成能力 ,含有NAA激素组合诱导的子叶愈伤组织总异黄酮含量较高 ,而 2 ,4-D/BA组合诱导的下胚轴愈伤组织总异黄酮含量较高 ,高浓度 2 ,4-D/KT组合抑制子叶和下胚轴愈伤组织积累异黄酮。愈伤组织根据发育的形态特征可分为 4种类型 ,以黄色、疏松、颗粒状的Ⅱ型愈伤组织中总异黄酮含量最高。结论 :培养基与激素组合影响愈伤组织的形成及发育形态特征 ,并反映在愈伤组织异黄酮合成差异上 ,获得的黄色、疏松颗粒状愈伤组织为后续的细胞液体悬浮培养及异黄酮合成代谢的调控研究奠定了基础。     

根癌农杆菌对云南红豆杉原生质体的转化

本文介绍了根癌农杆菌T-DNA对云南红豆杉原生质体的转化,分析了转化系的紫杉醇合成能力。实验以生长20 d的云南红豆杉幼茎诱导的淡黄色愈伤组织为材料,经酶解可分离出大量有活力的原生质体。在由B5无机盐、KM有机成分、3.0 mg/L 2,4-D、0.1mg/L KT和0.45 mol/L果糖组成的培养基中培养1周后,原生质体再生细胞持续分裂形成细胞团。根癌农杆菌对原生质体的转化能力与原生质体生长状态及菌株相关。虽然刚分离的或已再生细胞壁的原生质体不能被根癌农杆菌转化,但由10个以上细胞组成的原生质体克隆和根癌农杆菌B6S3菌株共培养后可实现T-DNA转化,高压纸电泳检测转化系具有冠瘿碱的合成,转化率约为5％。HPLC证实转化系具有合成紫杉醇的能力,但不同转化系中紫杉醇含量变异很大,最高含量为0.076％,是对照愈伤组织的6倍,表明T-DNA的插入改变了培养细胞对紫杉醇的合成。获得的高产转化系细胞生长比对照低,但继代培养中其生长和紫杉醇积累基本保持稳定。尽管转化系合成紫杉醇能力远未达到商业化生产的要求,但研究通过T-DNA对原生质体的转化而实现插入诱变,可以为分离高产紫杉醇优良细胞系提供单细胞筛选系统。     

千层塔内生真菌分离鉴定的初步研究

目的从治疗老年痴呆药用植物千层塔中分离内生真菌，并进行初步鉴定。方法用PDA平板培养基分离菌株，对照真菌鉴定手册，根据菌株的菌落形态、大小、颜色、生长速率、质地、生长培养基颜色变化以及菌丝体和孢子的形态特征进行鉴定。结果从千层塔的茎中分离出4株内生真菌，分别属于顶孢霉属、单轴霉属、酵母和青霉属。结论首次从千层塔中分离和鉴定出4株内生真菌。     

Ginsenoside Rg1 ameliorates blood–brain barrier disruption and traumatic brain injury via attenuating macrophages derived exosomes miR-21 release

During the traumatic brain injury (TBI), improved expression of circulatory miR-21 serves as a diagnostic feature. Low levels of exosome-miR-21 in the brain can effectively improve neuroinflammation and blood–brain barrier (BBB) permeability, reduce nerve apoptosis, restore neural function and ameliorate TBI. We evaluated the role of macrophage derived exosomes-miR-21 (M-Exos-miR-21) in disrupting BBB, deteriorating TBI, and Rg1 interventions. IL-1β-induced macrophages (IIM)-Exos-miR-21 can activate NF-κB signaling pathway and induce the expressions of MMP-1, -3 and -9 and downregulate the levels of tight junction proteins (TJPs) deteriorating the BBB. Rg1 reduced miR-21-5p content in IIM-Exos (RIIM-Exos). The interaction of NMIIA–HSP90 controlled the release of Exos-miR-21, this interaction was restricted by Rg1. Rg1 could inhibit the Exos-miR-21 release in peripheral blood flow to brain, enhancing TIMP3 protein expression, MMPs proteolysis, and restricting TJPs degradation thus protected the BBB integrity. Conclusively, Rg1 can improve the cerebrovascular endothelial injury and hold the therapeutic potential against TBI disease.     

N-doped carbon dots from phenol derivatives for excellent colour rendering WLEDs

To achieve competitive fluorescence carbon dots (CDs), studies on regulating fluorescence of CDs under controlled, comparable conditions are in great demand. Herein, by changing the functional groups and nitrogenous existence forms in the precursors, three efficient yellow-green emissive N-doped CDs which have the same fluorescence peak wavelength but different photoluminescence quantum yields were realized through a facile hydrothermal method. The as-prepared CDs exhibit not only excited-independent emissions but also similar surface states. The best-performing CDs among the three products exhibits photoluminescence quantum yields of up to 24.4% in water and 53.3% in ethanol, abundant surface functional groups and its high N-doping degree would be the reason for its excellent performances. By washing and reduction processes, the emission evolution of the CDs was studied linking the changes of surface states. The fluorescence can certainly be attributed to the surface of the carbon dots, and the surface states control the photoluminescence features. Serving as a yellow-green colour conversion layer, the best CDs in the three products was used to fabricate a white light-emitting diode. The white light-emitting diode shows an excellent colour rendering index up to 93.3, suggesting broad application prospects of the CDs in lighting and display fields.

Yellow-green photoluminescence carbon dots with different quantum yields were realized and used to fabricate white LEDs.     

Genome characterization of a GII.6 norovirus strain identified in China

Noroviruses (NoVs) are the primary cause of non-bacterial acute gastroenteritis worldwide. Most NoV infections are caused by GII.4, but GII.6 is also an important genotype with a long-term persistence in human populations. In this study, the complete genome sequence of a NoV strain GZ2010-L96 isolated in China was identified and analyzed phylogenetically. The viral genome comprised 7550 nucleotides, and its phylogenetic analysis revealed that the strain belonged to GII.6 genotype. All reported GII.6 NoV capsid protein sequences were also collected for comparative analysis, and GZ2010-L96 was clustered into GII.6-b with other 8 strains. Meanwhile, it was found that 53 spots on viral capsid showed subcluster specificity according to multiple alignments. Moreover, homologous modeling of GZ2010-L96 based on comparison with GII.4 VA387 strain showed a different antigen distribution pattern. In summary, the genome of the GII.6 strain GZ2010-L96 detected in China was extensively characterized, and phylogenetic analyses of GII.6 NoVs based on the capsid proteins may reveal a different evolution process from the predominant genotype GII.4.