库克诺你果汁提取物体外清除自由基及抗氧化活性研究

本文对诺你果汁多糖、乙醇溶出物和乙酸乙酯萃取物体外对超氧阴离子(O2·)、羟自由基(·OH)、DPPH和脂质过氧化(LPO)的抑制作用进行了研究。超氧阴离子(O2·)由邻苯三酚自氧化产生;羟自由基(·OH)由Fenton反应产生;利用Fe2 诱发卵黄脂蛋白产生丙二醛(MDA),TBA法测定。所有测定均为分光光度法。结果表明,与已知抗氧化剂L抗坏血酸相比,乙醇溶出物和乙酸乙酯萃取物均有明显的捕捉自由基和抗氧化能力,而多糖捕捉自由基和抗氧化能力很低,且对O2·没有抑制作用,反而会增加其生成速度。     

Host range, purification and some properties of a new ilarvirus from Humulus japonicus

In 1986, during routine quarantine testing, an apparently undescribed virus was isolated from two of 21 plants of Humulus japonicus grown from seed imported into the UK from Beijing, Peoples Republic of China. The virus, for which we propose the name humulus japonicus virus (HJV), was transmitted mechanically to a wide range of herbaceous plants. No symptoms were seen in virus-infected H. japonicus plants. HJV infected, but did not become systemic, in the cultivated hop (Humulus lupulus) under our conditions although it has been detected serologically in both species of Humulus growing near Beijing. The virus was transmitted through seed of Chenopodium quinoa and was also associated externally with pollen of that species, but no pollen-transmission tests were conducted. HJV was easily purified. Virus particles comprised a single polypeptide (mol. wt c. 26 350) and four RNA molecules (mol. wts 1.31, 1.05, 0.75 and 0.39×10⁶). The three larger mol. wt RNAs were not infective in the absence of the smallest RNA. The particles were quasi-isometric and variable in size. Purified preparations of particles formed four bands in sucrose density gradients but (after fixing with formaldehyde) only a single band (with a density of 1.364 g/ml) in caesium chloride isopycnic gradients. These properties are similar to those of ilarviruses, and HJV was very distantly related serologically to prunus necrotic ringspot ilarvirus. We suggest, therefore, that HJV be regarded as a new member of the ilarvirus group. All known infected plants of H. japonicus at the site of introduction have been destroyed and the virus has probably been eliminated from there. Testing is continuing to confirm this.     

Spatial organization of the North Island Brown Kiwi Apteryx australis mantelli: sex, pairing status and territoriality

In Waitangi State Forest, 51 North Island Brown Kiwi Apteryx australis mantelli were tagged with radio transmitters and observed for an average of 2.3 months. All females and the majority of males were paired and maintained territories of 6.7 and 5.5 ha, respectively. Territories overlapped widely between partners but only narrowly with those of paired neighbours. Unpaired males had territories of 12.8 ha and extensively overlapped those of paired males. Territories were maintained by long distance calls and rare aggressive encounters. Males were more territorial than females. Within pairs, males called 1.5 times more often than females and initiated most pair calls. 60% of female calls were responses to their mates. Observers could often induce aggressive behaviour (calling, fast approach) in male kiwi (by playback, for example) but hardly ever in females. Kiwi territoriality cannot be explained by the distribution and availability of food and shelter sites, but seems to serve mainly a reproductive function.     

Comparative vegetative anatomy and systematics of the Oncidiinae (Maxillarieae, Orchidaceae)

Subtribe Oncidiinae comprises a vegetatively heterogeneous assemblage of species that has persistently been incapable of organization. Anatomy was considered to be a possible means to resolve the perplexity of relationships amongst the constituent taxa. The consistent occurrence of a foliar hypodermis, homogeneous mesophyll, conical silica bodies in stegmata, and ubiquitous fibre bundles in leaves provides a matrix for linking the taxa, as do the parenchymatous pith and O-thickened endodermal cell walls in roots. However, the strict consensus of the 40 genera studied was completely unresolved, suggesting that vegetative characters alone are insufficient to assess the relationships amongst these taxa, a conclusion also reached for the remainder of Maxillarieae.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 91–107.     

The Southern Bluefin Tuna Arbitral Tribunal Did Get It Right: A Commentary and Reply to the Article by David A. Colson and Dr. Peggy Hoyle

This contribution is a reply to and a commentary on the article by David A. Colson and Dr. Peggy Hoyle, "Satisfying the Procedural Prerequisites to the Compulsory Dispute Settlement Mechanisms of the 1982 Law of the Sea Convention: Did the Southern Bluefin Tuna Tribunal Get It Right?" 34(1) Ocean Development & International Law 59-82 (2003). Colson and Hoyle took the view that Southern Bluefin Tuna Tribunal did not reach the correct answer. The author's survey of the Southern Bluefin Tuna and the Mox Plant cases, in light of the doctrine of procedural and substantive parallelism between the umbrella UN Law of the Sea Convention and its numerous implementing special treaties covered by Articles 281-282, leads her to conclude that the Southern Bluefin Tuna Arbitral Tribunal did get it right.­     

Drivers of radial growth and carbon isotope discrimination of bur oak (Quercus macrocarpa Michx.) across continental gradients in precipitation,vapour pressure deficit and irradiance

Tree‐ring characteristics are commonly used to reconstruct climate variables, but divergence from the assumption of a single biophysical control may reduce the accuracy of these reconstructions. Here, we present data from bur oaks (Quercus macrocarpa Michx.) sampled within and beyond the current species bioclimatic envelope to identify the primary environmental controls on ring‐width indices (RWIs) and carbon stable isotope discrimination (Δ¹³C) in tree‐ring cellulose. Variation in Δ¹³C and RWI was more strongly related to leaf‐to‐air vapour pressure deficit (VPD) at the centre and western edge of the range compared with the northern and wettest regions. Among regions, Δ¹³C of tree‐ring cellulose was closely predicted by VPD and light responses of canopy‐level Δ¹³C estimated using a model driven by eddy flux and meteorological measurements (R² = 0.96, P = 0.003). RWI and Δ¹³C were positively correlated in the drier regions, while they were negatively correlated in the wettest region. The strength and direction of the correlations scaled with regional VPD or the ratio of precipitation to evapotranspiration. Therefore, the correlation strength between RWI and Δ¹³C may be used to infer past wetness or aridity from paleo wood by determining the degree to which carbon gain and growth have been more limited by moisture or light.     

2,3-BUTANEDIONE INACTIVATES THE [H]NITRENDIPINE BINDING SITES, WHEREAS DIETHYLPYROCARBONATE DOES NOT

The modification of [³H]nitrendipine binding sites in rabbit brain membranes with 2,3-butanedione and diethylpyrocarbonate was investigated. 2,3-Butanedione, an arginine-specific reagent, causes a dose- and time-dependent decrease in the number of [³H]nitrendipine binding sites without altering its dissociation constant. Scatchard analysis of the binding data shows that 50 mM 2,3-butanedione decreases the binding capacity of [³H]nitrendipine from a control value of 71 ± 6 fmol/mg of protein to 40 ± 3 fmol/mg of protein. Complete and selective protection against inactivation is provided by nifedipine. No decrease of [³H]nitrendipine binding occurs when membranes are pretreated with selective histidine reagent diethylpyrocarbonate. The results indicate that arginine but not histidine residue in

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-type calcium channel domain is critical for [³H]nitrendipine binding. Copyright © 1996 Elsevier Science Ltd     

Impact of elevated carbon dioxide on the rhizosphere communities of Carex arenaria and Festuca rubra

The increase in atmospheric carbon dioxide (CO₂) levels is predicted to stimulate plant carbon (C) fixation, potentially influencing the size, structure and function of micro- and mesofaunal communities inhabiting the rhizosphere. To assess the effects of increased atmospheric CO₂ on bacterial, fungal and nematode communities in the rhizosphere, Carex arenaria (a nonmycorrhizal plant species) and Festuca rubra (a mycorrhizal plant species) were grown in three dune soils under controlled soil temperature and moisture conditions, while subjecting the aboveground compartment to defined atmospheric conditions differing in CO₂ concentrations (350 and 700 μL L⁻¹). Real-time polymerase chain reaction (PCR) and PCR-denaturing gradient gel electrophoresis methods were used to examine effects on the size and structure of rhizosphere communities. Multivariate analysis of community profiles showed that bacteria were most affected by elevated CO₂, and fungi and nematodes to a lesser extent. The influence of elevated CO₂ was plant dependent, with the mycorrhizal plant ( F. rubra ) exerting a greater influence on bacterial and fungal communities. Biomarker data indicated that arbuscular mycorrhizal fungi (AMF) may play an important role in the observed soil community responses. Effects of elevated CO₂ were also soil dependent, with greater influence observed in the more organic-rich soils, which also supported higher levels of AMF colonization. These results indicate that responses of soil-borne communities to elevated CO₂ are different for bacteria, fungi and nematodes and dependent on the plant type and soil nutrient availability.     

Process‐Based Species Action Plans: an approach to conserve contemporary evolutionary processes that sustain diversity in taxonomically complex groups

Many endemic plant species belong to taxonomically complex groups. These endemics have often arisen as a consequence of recent and rapid evolutionary divergence facilitated by processes such as hybridization, polyploidy and/or breeding system transitions. The rapid and dynamic nature of divergence in taxonomically complex groups leads to problems in the implementation of traditional species‐based approaches for the conservation of the biodiversity that they contain. Firstly, the taxa of interest can be difficult to define and identify, leading to practical difficulties in implementing conservation measures. Secondly, a species‐based approach often fails to capture the complexity of diversity present in the taxonomically complex group. To accommodate these challenges, we have developed a Process‐Based Species Action Plan approach. This is designed to conserve the processes leading to the generation of biodiversity, rather than focusing on the preservation of individual named taxa. We illustrate the approach using a group of endemic tree species (Sorbus) on the Scottish island of Arran that have originated via a combination of multiple recent hybridization events and apomixis. The plan focuses on the optimization of habitat management to ensure the reproduction and regeneration of Sorbus in the zone in which these evolutionary processes operate, and to facilitate hybridization that will ensure the continued generation of diversity in this group. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 168 , 194–203.