不同生长期罗汉果蛋白组图谱比较研究

目的:分析、比较30d和60d两个不同时期罗汉果蛋白质组图谱,寻找与罗汉果发育、成熟及罗汉果甜甙生成密切相关基因,为罗汉果的开发和品种改良提供基础。方法:采用双向电泳(2-DE)技术构建30d和60d罗汉果蛋白质组图谱,应用Im-ageMaster 2D图像分析软件对所得蛋白质组图谱进行分析。结果:30d和60d两个不同时期罗汉果蛋白质组图谱有明显差别,与30d罗汉果蛋白组图谱比较,随果实发育、成熟,60d罗汉果有29个新的蛋白产生,30个蛋白消失,16个蛋白表达3倍升高和15个蛋白表达50%下调。结论:罗汉果生长、发育和成熟的不同阶段受特定基因的表达调控。     

不同生长周期的罗汉果鲜果中甜甙V和总黄酮含量变化规律研究

通过使用HPLC法对不同生长周期的罗汉果鲜果中罗汉果甜甙V和总黄酮的含量进行测定,总结出罗汉果中罗汉果甜甙V和总黄酮含量的变化规律,并对二者进行比较研究,结果表明坐果50d后,罗汉果甜甙Ⅴ的增加比较快,80d后,罗汉果甜甙Ⅴ的含量趋于稳定;随着生长周期的增加,罗汉果总黄酮的含量增加,40～50d中增长最快,坐果约50d后达到最高值,从60d开始总黄酮的含量迅速下降到20d水平,然后趋于稳定。     

桂北地区不同品种、不同产地鲜罗汉果中总甙、甙V含量测定

分别采用紫外分光光度比色法(UV-vis)和高效液相色谱法(HPLC)测定了不同产地,不同品种罗汉果中的总甙和甙V的含量。测定结果表明:同一品种不同产地罗汉果中总甙含量、甙V成分变化不大,不同品种的总甙、甜味成分V均有明显差别。     

不同产地罗汉果总皂苷、甜苷V和硒含量及指纹图谱研究

对不同产地同一品种收获期罗汉果总皂苷、甜苷V和硒的含量进行比较,了解罗汉果的品质特点与产地的相关性,科学指导种植区域的生产规划,明确不同区域罗汉果的品质特点和开发等直接关系到罗汉果深加工产业的质量与发展。采用香草醛-浓硫酸试剂分光光度比色法分别测量各罗汉果果实样品中总皂苷的含量,采用高效液相色谱法测量甜苷V的含量,采用氢化物原子荧光光谱法测量其中硒的含量,并对各指标进行方差分析和差异显著性的多重比较。结果表明,各样品总皂苷含量在2.42%~3.34%之间,甜苷V含量在0.68%~1.41%之间,硒含量在5.634~41.462μg/kg之间;来源于不同产地的罗汉果样品,其总皂苷含量差异并不显著,但甜苷V和硒含量分别表现出显著差异;广西、湖南和四川,罗汉果果实总皂苷和甜苷V含量均可达到药典指标要求。因此,罗汉果具有较广的种植区域,但不同产地甜苷V含量差异相对显著,暗示果实甜苷V的转化效率或成熟度具有一定差异,宜根据产地及年度气候条件适当调整收获期,以满足不同加工利用的需要。     

HPLC法测定不同生长期罗汉果甙ⅡE、Ⅲ、Ⅴ的含量

采用HPLC法测定同一产地不同生长期罗汉果中罗汉果甙ⅡE、Ⅲ、Ⅴ的含量。结果表明,在生长初期罗汉果中主要含具有苦味的甙Ⅱ及无味的甙Ⅲ,随着生长期的增加,苦味甙ⅡE、无味甙III含量逐渐减少,甜甙Ⅴ在50d时开始出现,并随生长期增加,到80d后含量达到最高。     

Analysis of glycyrrhizic acid and liquiritin in liquorice root with microwave-assisted micellar extraction and pre-concentration

The feasibility of employing a non-ionic surfactant (Triton X-100) as an alternative and effective solvent for the microwave-assisted extraction of glycyrrhizic acid and liquiritin from liquorice root has been demonstrated. When compared with commonly used solvents, 5% Triton X-100 yielded higher extraction efficiency than aqueous solutions of ethanol or methanol. Under optimal conditions, i.e. 5% Triton X-100 (v/v) and microwave-assisted extraction for 3-5 min at 100 degrees C, the percentage extraction of active ingredients reached the highest value. The pre-concentration factor for the glycyrrhizic acid and liquiritin was about 13, and the cloud-point extraction recoveries for the two ingredients were 98.4 and 96.1%, respectively. The results showed that the coupling of microwave-assisted extraction and cloud-point extraction could be employed as a new and effective approach for the rapid extraction and pre-concentration of pharmacologically active ingredients from liquorice root without disturbing the subsequent chromatographic analysis.     

Crystal structure of yeast V1‐ATPase in the autoinhibited state

Vacuolar ATPases (V‐ATPases) are essential proton pumps that acidify the lumen of subcellular organelles in all eukaryotic cells and the extracellular space in some tissues. V‐ATPase activity is regulated by a unique mechanism referred to as reversible disassembly, wherein the soluble catalytic sector, V₁, is released from the membrane and its MgATPase activity silenced. The crystal structure of yeast V₁ presented here shows that activity silencing involves a large conformational change of subunit H, with its C‐terminal domain rotating ~150° from a position near the membrane in holo V‐ATPase to a position at the bottom of V₁ near an open catalytic site. Together with biochemical data, the structure supports a mechanistic model wherein subunit H inhibits ATPase activity by stabilizing an open catalytic site that results in tight binding of inhibitory ADP at another site.     

Characterisation of Phenolics in Flor‐Essence®—a Compound Herbal product and its Contributing Herbs

Introduction – Commercially available herbal mixture FE, a proprietary natural health product manufactured by Flora Manufacturing and Distributing Ltd (Flora), is a unique North American traditional herbal product. FE is a chemically complex mixture of eight herbs and has not been subjected to phytochemical analysis. Objective – To develop analytical methods to undertake detailed phytochemical analyses of FE, and its eight contributing herbs, including burdock (Arctium lappa L.), sheep sorrel (Rumex acetosella L.), Turkish rhubarb (Rheum palmatum L.), slippery elm Muhl. (Ulmus rubra), watercress (Nasturtium officinale R. Br.), red clover (Trifolium pratense L.), blessed thistle (Cnicus benedictus L.) and kelp (Laminaria digitata Lmx.). Methodology – The identification was undertaken by a combination of reversed phase high performance liquid chromatography–diode array detection–atmospheric pressure chemical ionisation–mass selective detection (RP‐HPLC‐DAD‐APCI‐MSD) analysis and phenolics metabolomic library matching. Results – New separation methods facilitated the identification of 43 markers in the individual herbs which constitute FE. Sixteen markers could be identified in FE originating from four contributing herbs including four caffeoyl quinic acids, three dicaffeoyl quinic acids and two caffeic acid derivatives from A. lappa, luteolin‐7‐O‐glucoside, luteolin, five apigenin glycosides and apigenin from R. acetocella and N. officinale and sissostrin from T. pretense. A validated method for quantitative determination of three markers is reported with good intraday, interday and interoperator repeatability using a reliable alcohol based extraction technique. Conclusion – FE and its contributing herbs predominantly contain phenolics. This methodology can be applied to further develop full‐scale validation of this product. Copyright © 2009 John Wiley & Sons, Ltd.     

Unifying Charge Generation,Recombination, and Extraction in Low‐Offset Non‐Fullerene Acceptor Organic Solar Cells

Even though significant breakthroughs with over 18% power conversion efficiencies (PCEs) in polymer:non‐fullerene acceptor (NFA) bulk heterojunction organic solar cells (OSCs) have been achieved, not many studies have focused on acquiring a comprehensive understanding of the underlying mechanisms governing these systems. This is because it can be challenging to delineate device photophysics in polymer:NFA blends comprehensively, and even more complicated to trace the origins of the differences in device photophysics to the subtle differences in energetics and morphology. Here, a systematic study of a series of polymer:NFA blends is conducted to unify and correlate the cumulative effects of i) voltage losses, ii) charge generation efficiencies, iii) non‐geminate recombination and extraction dynamics, and iv) nuanced morphological differences with device performances. Most importantly, a deconvolution of the major loss processes in polymer:NFA blends and their connections to the complex BHJ morphology and energetics are established. An extension to advanced morphological techniques, such as solid‐state NMR (for atomic level insights on the local ordering and donor:acceptor π? π interactions) and resonant soft X‐ray scattering (for donor and acceptor interfacial area and domain spacings), provide detailed insights on how efficient charge generation, transport, and extraction processes can outweigh increased voltage losses to yield high PCEs.     

Nonparametric One‐way Analysis of Variance of Replicated Bivariate Spatial Point Patterns

A common problem in neuropathological studies is to assess the spatial patterning of cells on tissue sections and to compare spatial patterning between disorder groups. For a single cell type, the cell positions constitute a univariate point process and interest focuses on the degree of spatial aggregation. For two different cell types, the cell positions constitute a bivariate point process and the degree of spatial interaction between the cell types is of interest. We discuss the problem of analysing univariate and bivariate spatial point patterns in the one‐way design where cell patterns have been obtained for groups of subjects. A bootstrapping procedure to perform a nonparametric one‐way analysis of variance of the spatial aggregation of a univariate point process has been suggested by Diggle, Lange and Bene? (1991). We extend their replication‐based approach to allow the comparison of the spatial interaction of two cell types between groups, to include planned comparisons (contrasts) and to assess whole groups against complete spatial randomness and spatial independence. We also accommodate several replicate tissue sections per subject. An advantage of our approach is that it can be applied when processes are not stationary, a common problem in brain tissue sections since neurons are arranged in cortical layers. We illustrate our methods by applying them to a neuropathological study to investigate abnormalities in the functional relationship between neurons and astrocytes in HIV associated dementia. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Analysis of sesquiterpene lactones in Eupatorium lindleyanum by HPLC‐PDA‐ESI‐MS/MS

Introduction – The aerial part Eupatorium lindleyanum is commonly used as an antipyretic and detoxicant clinically in traditional Chinese medicine. Our previous research showed that germacrane sesquiterpene lactones were its main active constituents, so the development of rapid and accurate methods for the identification of the sesquiterpene lactones is of great significance. Objective – To develop an HPLC‐PDA‐ESI‐MS/MS method capable for simple and rapid analysis of germacrane sesquiterpene lactones in the aerial part E. lindleyanum. Methodology – High‐performance liquid chromatography‐photodiode array detection‐electrospray ionization‐tandem mass spectrometry was used to analyze germacrane sesquiterpene lactones of Eupatorium lindleyanum. The fragmentation behavior of germacrane sesquiterpene lactones in a Micromass Q/TOF Mass Spectrometer was discussed, and 9 germacrane sesquiterpene lactones were identified by comparison of their characteristic data of HPLC and MS analyses with those obtained from reference compounds. Results – The investigated germacrane sesquiterpene lactones were identified as eupalinolides C (1), 3β‐acetoxy‐8β‐(4′‐hydroxy‐tigloyloxy)‐14‐hydroxy‐costunolide (2), eupalinolides A (3), eupalinolides B (4), eupalinolides E (5), 3β‐acetoxy‐8β‐(4′‐oxo‐tigloyloxy)‐14‐hydroxy‐heliangolide (6), 3β‐acetoxy‐8β‐(4′‐oxo‐ tigloyloxy)‐14‐hydroxy‐costunolide (7), hiyodorilactone B (8), and 3β‐acetoxy‐8β‐(4′‐hydroxy‐tigloyloxy)‐ costunolide (9). Compounds 6, 7 and 9 were reported for the first time. Conclusion – HPLC‐PDA‐ESI‐MS/MS provides a new powerful approach to identify germacrane sesquiterpene lactones in E. lindleyanum rapidly and accurately. Copyright © 2009 John Wiley & Sons, Ltd.     

Nanoflake‐Assembled Hierarchical Na3V2(PO4)3/C Microflowers: Superior Li Storage Performance and Insertion/Extraction Mechanism

Na₃V₂(PO₄)₃ (NVP) has excellent electrochemical stability and fast ion diffusion coefficient due to the 3D Na⁺ ion superionic conductor framework, which make it an attractive cathode material for lithium ion batteries (LIBs). However, the electrochemical performance of NVP needs to be further improved for applications in electric vehicles and hybrid electric vehicles. Here, nanoflake‐assembled hierarchical NVP/C microflowers are synthesized using a facile method. The structure of as‐synthesized materials enhances the electrochemical performance by improving the electron conductivity, increasing electrode–electrolyte contact area, and shortening the diffusion distance. The as‐synthesized material exhibits a high capacity (230 mAh g^?1), excellent cycling stability (83.6% of the initial capacity is retained after 5000 cycles), and remarkable rate performance (91 C) in hybrid LIBs. Meanwhile, the hybrid LIBs with the structure of NVP || 1 m LiPF₆/EC (ethylene carbonate) + DMC (dimethyl carbonate) || NVP and Li₄Ti₅O₁₂ || 1 m LiPF₆/EC + DMC || NVP are assembled and display capacities of 79 and 73 mAh g^?1, respectively. The insertion/extraction mechanism of NVP is systematically investigated, based on in situ X‐ray diffraction. The superior electrochemical performance, the design of hybrid LIBs, and the insertion/extraction mechanism investigation will have profound implications for developing safe and stable, high‐energy, and high‐power LIBs.     

NaCa0.6V6O16·3H2O as an Ultra‐Stable Cathode for Zn‐Ion Batteries: The Roles of Pre‐Inserted Dual‐Cations and Structural Water in V3O8 Layer

Rechargeable aqueous batteries with Zn²⁺ as a working‐ion are promising candidates for grid‐scale energy storage because of their intrinsic safety, low‐cost, and high energy‐intensity. However, suitable cathode materials with excellent Zn²⁺‐storage cyclability must be found in order for Zinc‐ion batteries (ZIBs) to find practical applications. Herein, NaCa_0.6V₆O₁₆·3H₂O (NaCaVO) barnesite nanobelts are reported as an ultra‐stable ZIB cathode material. The original capacity reaches 347 mAh g^?1 at 0.1 A g^?1, and the capacity retention rate is 94% after 2000 cycles at 2 A g^?1 and 83% after 10 000 cycles at 5 A g^?1, respectively. Through a combined theoretical and experimental approach, it is discovered that the unique V₃O₈ layered structure in NaCaVO is energetically favorable for Zn²⁺ diffusion and the structural water situated between V₃O₈ layers promotes a fast charge‐transfer and bulk migration of Zn²⁺ by enlarging gallery spacing and providing more Zn‐ion storage sites. It is also found that Na⁺ and Ca²⁺ alternately suited in V₃O₈ layers are the essential stabilizers for the layered structure, which play a crucial role in retaining long‐term cycling stability.