Food mixing by generalist grasshoppers: Plant secondary compounds structure the pattern of feeding

Plant secondary compounds can prevent feeding by phytophagous insects or, if ingested, can be poisonous to them. Less attention has been paid to the additional effects they have on feeding behavior when they are only weakly deterrent or not deterrent at all. Experiments were carried out on the generalist grass-hopperSchistocerca americana. Individuals were presented either with two cakes of high-quality artificial food with a single deterrent compound added or with two cakes, each with a different added deterrent compound. The deterrents consisted of single plant secondary compounds that were either marginally or strongly deterrent. There were profound differences in feeding behavior between those individuals given identical and those given different cake types, including longer feeding bouts on single cakes when a choice of different cake types was available. The behavioral effects demonstrate that the presence of secondary compounds in one food can influence the patterns of feeding on other available foods and suggest that such chemicals could impact foraging activities in a complex manner.     

海洋药物的抗病毒研究

海洋由于其特殊的生态环境,包含着极其丰富的生物来源的天然产物。自本世纪七十年代以来,已经从海藻类、海绵类、海鞘类、海星类、腹足动物、棘皮动物、腔肠动物、软体动物、珊瑚及海洋微生物等海洋生物中分离出一系列有抗病毒作用的天然化合物,其中有些结构类型已成为抗病毒药物研究的导向化合物。基于现代分离和分析技术的发展、新的实验模型的建立和在病毒学方面分子生物学研究的进展,从海洋生物中寻找新的抗病毒药物已步入一个新的时代。     

消痰化瘀利窍中药组方对改善慢性间歇性低氧大鼠心肌纤维化的作用及其机制*

目的: 探讨转化生长因子-β(TGF-β)信号通路在消痰化瘀利窍中药组方(XC)对改善慢性间歇性低氧(CIH)大鼠心肌纤维化中的作用。方法: 40只SD 大鼠,随机分为常氧组(Normoxia)、常氧+中药干预组(TCMC)、慢性间歇性低氧模型组(CIH)、CIH +中药干预组(TCMC+CIH),每组10只。通过向舱内充入氮气,使舱内氧体积分数在90 s内从21%下降到9%,随后90 s再充氧气使舱内氧体积分数逐渐上升到21%为一循环建立CIH模型。CIH 与 TCMC+CIH 组大鼠置于CIH装置, Normoxia 和TCMC组大鼠置于正常氧舱。此外TCMC+CIH 与 TCMC 组大鼠于每日XC生药(24 g/kg)煎制灌胃,而 CIH 组与 Normoxia 组大鼠给予等体积生理盐水。造模结束后,天狼星红染色观察大鼠心肌间质内胶原沉积情况;Western blot 法检测大鼠心肌间质中 CollagenⅠ、Collagen Ⅲ、Fibronectin、TGF-β、p-Smad2、p-Smad3的蛋白表达水平。采用Q-PCR法检测基质金属蛋白酶2(MMP-2)和基质金属蛋白酶抑制因子 2 (TIMP-2) 的 mRNA表达水平。结果: 与正常组比较,CIH大鼠心肌组织出现明显胶原的沉积,CollagenⅠ、Collagen Ⅲ和Fibronectin蛋白表达明显增多(P均＜0.01),TGF-β、p-Smad2、p-Smad3蛋白表达水平也明显增高(P均＜0.01);CIH大鼠心肌组织TIMP-2 mRNA上调导致MMP-2 mRNA明显减少(P均＜0.01)。给予XC干预后,CIH大鼠心肌组织胶原沉积明显减少,CollagenⅠ、Collagen Ⅲ和Fibronectin蛋白表达明显降低(P＜0.05,P＜ 0.01,P＜0.05);CIH大鼠心肌组织中TGF-β、p-Smad2、p-Smad3蛋白表达水平明显降低(P＜0.01,P＜0.05,P＜ 0.01)。心肌组织中TIMP-2明显基因减少致MMP-2增多(P均＜0.05)。 结论: 消痰化瘀利窍中药组方可抑制CIH大鼠心肌纤维化的形成,进而改善CIH大鼠心肌功能。其机制与该中药组方下调TGF-β/ Smad2/3信号通路及下调TIMP-2mRNA有关。     

Self-excreted mediator from <Emphasis Type="Italic">Escherichia coli</Emphasis> K-12 for electron transfer to carbon electrodes

Escherichia coli K-12 was cultured under anaerobic conditions to form biofilm on carbon fiber electrodes in glucose-containing medium. The anodic current increased with the development of the biofilm and depended on the glucose concentration. Cyclic voltammetric results support the presence of a redox compound(s) excreted from E. coli cells in the biofilm. The compound remained in the film under conditions of continuous flow and gave a couple of oxidation and reduction waves, which may be assigned to a menaquinone-like compound based on the mid-point potential (−0.22 V vs Ag|AgCl at pH 7.1) and its pH dependence. The catalytic current started to increase around the anodic peak potential of the redox compound and also increased by the permeabilization of the E. coli cell membranes with ethylenediamine tetraacetic acid-treatment. The results indicate that the E. coli-excreted redox compound works as a mediator for the electron transfer from the E. coli cells to the electrode as the final electron acceptor. The activity of the redox compound in the E. coli-biofilm as a mediator with some mobility was also verified for diaphorase-catalyzed electrochemical oxidation of NADH.     

Spectroscopic description of an unusual protonated ferryl species in the catalase from <Emphasis Type="Italic">Proteus mirabilis</Emphasis> and density functional theory calculations on related models. Consequences for the ferryl protonation state in catalase,peroxidase and chloroperoxidase

The catalase from Proteus mirabilis peroxide-resistant bacteria is one of the most efficient heme-containing catalases. It forms a relatively stable compound II. We were able to prepare samples of compound II from P. mirabilis catalase enriched in ⁵⁷Fe and to study them by spectroscopic methods. Two different forms of compound II, namely, low-pH compound II (LpH II) and high-pH compound II (HpH II), have been characterized by Mössbauer, extended X-ray absorption fine structure (EXAFS) and UV-vis absorption spectroscopies. The proportions of the two forms are pH-dependent and the pH conversion between HpH II and LpH II is irreversible. Considering (1) the Mössbauer parameters evaluated for four related models by density functional theory methods, (2) the existence of two different Fe–O_ferryl bond lengths (1.80 and 1.66 Å) compatible with our EXAFS data and (3) the pH dependence of the α band to β band intensity ratio in the absorption spectra, we attribute the LpH II compound to a protonated ferryl Fe^IV–OH complex (Fe–O approximately 1.80 Å), whereas the HpH II compound corresponds to the classic ferryl Fe^IV=O complex (Fe=O approximately 1.66 Å). The large quadrupole splitting value of LpH II (measured 2.29 mm s^?1 vs. computed 2.15 mm s^?1) compared with that of HpH II (measured 1.47 mm s^?1 vs. computed 1.46 mm s^?1) reflects the protonation of the ferryl group. The relevancy and involvement of such (Fe^IV=O/Fe^IV–OH) species in the reactivity of catalase, peroxidase and chloroperoxidase are discussed.     

Preparation, crystal structure and magnetic property of a binuclear oxalate-bridged iron(III) compound: Fe2(C2O4)Cl4(DMF)4 (DMF = dimethylformamide)

An oxalato-bridged binuclear iron(III) compound, Fe₂(C₂O₄)Cl₄(DMF)₄ (DMF = dimethylformamide), was obtained by electrocrystallization for three weeks at 3.4 V and it displays a strong antiferromagnetic interaction of J = −6.74(4) cm⁻¹.     

国产色谱柱在复方氨基酸输液含量测定中的应用研究

运用两种国产色谱柱检测复方氨基酸注射液中各氨基酸的含量,分别建立了分离检测方法,优化了梯度洗脱的条件。在waters和agilent的高效液相仪上,两个厂家的色谱柱均显示出较好的分离效果。结果表明国产色谱柱能经济有效的达到质量控制的目的,可以推广使用。     

Pollen morphology of the tribes Naucleeae and Hymenodictyeae (Rubiaceae – Cinchonoideae) and its phylogenetic significance

The tribe Naucleeae has recently been recircumscribed on the basis of both morphological and molecular [ rbcL , trnT-F , internal transcribed spacer (ITS)] evidence, and has been found to be the sister group of the tribe Hymenodictyeae Razafim. & B. Bremer. In order to find pollen morphological support for this new classification, the pollen and orbicules of 65 species, representing 23 Naucleeae and the two Hymenodictyeae genera, were investigated by scanning electron and light microscopy. Naucleeae pollen is very small (< 20 µm) to small (20–30 µm) and its shape in equatorial view is suboblate to spheroidal or, more rarely, subprolate. Three compound apertures are present, each comprising a long and narrow ectocolpus, a circular to slightly lolongate mesoporus, and an often H-shaped endoaperture. The sexine ornamentation is perforate, rugulate, or (micro)reticulate, and supratectal elements are always absent. Apart from the variation in sexine ornamentation, the tribe is rather stenopalynous. The pollen of Hymenodictyeae is very similar to that of Naucleeae. The H-shaped endoapertures often observed probably form a synapomorphy for the clade comprising Naucleeae and Hymenodictyeae. Our pollen morphological observations are not in conflict with the widened delimitation of Naucleeae. Unambiguous pollen support for the recent subtribal or generic concepts of Naucleeae could not be found because of a lack of variation of pollen characters within the tribe. Orbicules are invariably present in the ten Naucleeae taxa investigated. They are spheroidal and smooth or irregularly folded.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 153 , 329–341.     

A Novel Optimization of Water-Soluble Compound Polysaccharides from Chinese Herbal Medicines by Quantitative Theory and Study on Its Characterization and Antioxidant Activities

The present study optimized the extraction characterization and antioxidant activities of water-soluble compound polysaccharides (CPs) from hawthorn, lotus leaf, Fagopyrum tataricum, semen cassiae, Lycium barbarum, and Poria cocos Chinese herbal medicines that have mass ratios of 4 : 2 : 2 : 1.5 : 1 : 1. The CPs yield equation was predicted using quantitative theory, to which a maximum CPs yield of 7.18±0.24 % under the following optimal extraction conditions: a water-to-raw material ratio of 30 mL/g, an extraction temperature of 65 °C, an extraction time of 45 min, and extraction mode ultrasonic-assistant extraction. CPs were consisted of Ara, Gal, Glc, Xyl, Man, GalA and GlcA in a molar ratio of 3.1 : 2.6 : 50.6 : 1.7 : 20.4 : 17.2 : 4.2. The HPGPC profiles and FT-IR spectra implied that CPs were heterogeneous acidic polysaccharides and possessed the β-d -pyranose configuration. Congo red test, CD spectrum and SEM revealed that CPs with three helix conformation showed a flocculent, granulous or sheet-like appearance. Furthermore, the relationships between antioxidant activity and concentration of CPs displayed significant positive correlation, and the scavenging abilities for DPPH, hydroxyl radical, ABTS, superoxide-anion radical and reducing power of CPs were 93.56±2.51 %, 84.03±1.69 %, 83.29±1.93 %, 37.49±1.93 % and 0.467±0.006 at a concentration of 4.0 mg/mL. Therefore, CPs could be applied as a potential natural antioxidant in pharmaceutical or functional food fields.     

中华蜜蜂气味结合蛋白AcerOBP14的表达及配体结合特性分析

[目的]气味结合蛋白(odorant binding proteins,OBPs)在昆虫寄主定位、产卵地选择等行为中发挥着重要作用,明确中华蜜蜂Apis cerana cerana AcerOBP14与配体的结合特性有助于阐明中华蜜蜂嗅觉识别的分子机制.[方法]通过qRT-PCR测定OBP14在20日龄中华蜜蜂成年工蜂...