切断海马伞对大鼠硬性脑挫伤后运动行为恢复的影响

硬性挫伤运动皮层诱发大鼠偏瘫及其随后的行为代偿是研究中枢神经可塑性的一个理想模型。本工作观察了切断海马伞对脑挫伤后行为恢复的影响。结果表明：与对照组相比,(1)切断海马伞—穹隆通路明显延缓了大鼠运动平衡能力的恢复;(2)切断海马伞—穹隆通路后,银杏类黄酮(FGb)失去了促进脑挫伤后运动平衡能力恢复的作用;(3)原位杂交显示,脑损伤后海马DG(齿状回)和CA3区中生长相关蛋白(GAP—43)mRNA的水平明显提高;(4)FGb促进脑损伤后海马DG和CA3区中的GAP—43mRNA水平的上调。这些信息提示,海马参与脑硬性挫伤后的运动代偿,FGb促进脑损伤后的运动行为的恢复可能与海马相关[动物学报49(2)：211-217,2003]。     

豆突眼长蝽发育起点温度和有效积温的研究

在恒温条件下 ,观察了不同温度对豆突眼长蝽ChauliopsfallaxScott生长发育的影响 ,用直接最优法和直线回归法分析数据 ,结果表明直接最优法能较好地反应实际情况。卵、1～ 5龄若虫和整个若虫期的发育起点温度分别为 7 98℃ ,7 1 6℃ ,6 5 3℃ ,8 81℃ ,6 75℃ ,8 2 7℃和 7 5 0℃ ,有效积温分别为85 8,60 8,5 2 0 ,71 4,1 0 1 5 ,66 3和 3 5 3 0日·度 ,发育速率最大时的温度分别为 3 4 84℃ ,3 4 48℃ ,3 4 1 6℃ ,3 4 1 2℃ ,3 4 75℃ ,3 5 1 1℃和 3 3 65℃。     

白蜡虫碱性磷酸酶功能基团的研究

白蜡ricerus pela雌成虫经匀浆,正丁醇抽提,硫酸铵分段盐析,SephadexG-150凝胶过滤等步骤,得到比活力为136.65U/mg蛋白酶制品,用苯甲基磺酰氟、N-溴代琥珀酰亚胺、三硝基苯磺酸、二巯基苏糖醇、对氯汞苯甲酸、琥珀酸酐、溴乙酸、碘乙酸等化学修饰剂在一定条件下选择修饰白蜡虫碱性磷酸酶的几种氨基酸残基,并测定酶活力变化。结果表明：苯甲基磺酰氟、N-溴代琥珀酰亚胺、三硝基苯磺酸、琥珀酸酐、二巯基苏糖醇的修饰能显著抑制酶的活力,活力的降低与修饰剂的浓度有关,氯汞苯甲酸、溴乙酸、碘乙酸的修饰对酶的抑制作用影响较小。初步认为：丝氨酸、赖氨酸和色氨酸残基是白蜡虫碱性磷酸酶的必需功能基团,部分二硫键也是酶的催化功能所必需的。     

外源甜菜碱对干旱胁迫下小麦幼苗膜脂过氧化作用的影响

用PEG4000溶液对小麦（Triticum aestivum L.heimang)幼苗进行胁迫处理和加入外源甜菜碱（Betaine)作同样处理,6、12、18和24h测定生理变化。结果表明,与对照相比,外源甜菜碱导致小麦幼苗叶片含水量下降,相对膜透性增大,MDA含量升高,SOD和POD活性先降后增,同时脯氨酸大量积累。说明外源甜菜碱对小麦幼苗受伤害程度有明显加深作用。     

SiO2‐Enhanced Structural Stability and Strong Adhesion with a New Binder of Konjac Glucomannan Enables Stable Cycling of Silicon Anodes for Lithium‐Ion Batteries

Silicon‐based anodes with high theoretical capacity have intriguing potential applications for next‐generation high‐energy lithium‐ion batteries, but suffer from huge volumetric change that causes pulverization of electrodes. Rational design and construction of effective electrode structures combined with versatile binders remain a significant challenge. Here, a unique natural binder of konjac glucomannan (KGM) is developed and an amorphous protective layer of SiO₂ is fabricated on the surface of Si nanoparticles (Si@SiO₂) to enhance the adhesion. Benefiting from a plethora of hydroxyl groups, the KGM binder with inherently high adhesion and superior mechanical properties provides abundant contact sites to active materials. Molecular mechanics simulations and experimental results demonstrate that the enhanced adhesion between KGM and Si@SiO₂ can bond the particles tightly to form a robust electrode. In addition to bridging KGM molecules, the SiO₂‐functionalized surface may serve as a buffer layer to alleviate the stresses of Si nanoparticles resulting from the volume change. The as‐fabricated KGM/Si@SiO₂ electrode exhibits outstanding structural stability upon long‐term cycles. A highly reversible capacity of 1278 mAh g^?1 can be achieved over 1000 cycles at a current density of 2 A g^?1, and the capacity decay is as small as 0.056% per cycle.     

A novel pro-apoptosis protein PNAS-4 from <Emphasis Type="Italic">Xenopus laevis</Emphasis>: Cloning,expression, purification,and polyclonal antibody production

Human PNAS-4 was identified as a novel pro-apoptotic protein in mammalian cells. Here we report the cloning, expression, purification, and antibody production of a PNAS-4 homolog (named xPNAS-4) from Xenopus laevis, an extensively used model organism in exploring gene functions during embryonic development. Recombinant histidine-tagged xPNAS-4 protein was expressed in Escherichia coli as insoluble inclusion bodies. The inclusion bodies were subsequently dissolved in 8 M urea and purified to near homogeneity by Ni2+ affinity chromatography. The resulting denatured protein was refolded by stepwise dilution of urea concentration via dialysis. This procedure yielded about 4 mg refolded protein per liter of E. coli culture with a purity of 95%. The purified protein was identified by liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry (LC-ESI-Q-TOF-MS) and used to raise anti-xPNAS-4 polyclonal antibodies that were suitable for detecting the expression of PNAS-4 in X. laevis embryos by Western blotting. The availability of recombinant protein and specific polyclonal antibodies will provide a valuable tool in studying apoptotic mechanisms of this protein. To our knowledge, this is the first report to demonstrate the presence of PNAS-4 in X. laevis.     

Studies on the Constituents of Aristolochia versicolar S. M. Hwang

Twenty-four constituents were isolated from the root of Aristolochia versicolar S. M. Hwang (collected from Guangxi province, China). Ten of them (two novel sesquiterpene lacrones and eight known compounds) were reported recently. This paper deals with the other eight compounds. From the petroleum ether extraction a sesquiterpene lactone, C15H20O2, mp. 94–95℃ [α]D36 –49˚ (C=1.8, EtOH), confirmed to be isoaristolactone, was obtained from plants for the first time. On the basis of spectral analysis (UV, IR, 1HNMR, 13CNMR, MS) and chemical reactions its structure was determined as B2. From the petroleum enter unsoluble sec- tion 6-methoxyaristolic acid methyl ester (D1), aristolic acid (D3), 6-methoxyaristolic acid (ari- stolinic acid) (D4f), 6-methoxyaristolochic acid methyl ester (D4y), aristolochic acid A(D5), β-sitosterol-D-glucoside (D10) and allantoin (C2) were isolated and identified. Dx, Ds, and Ds show ed antifertility activity in mice.     

Inhibition of PTEN Attenuates Endoplasmic Reticulum Stress and Apoptosis via Activation of PI3K/AKT Pathway in Alzheimer’s Disease

Amyloid plaques and neurofibrillary tangles are pathologic hallmarks of Alzheimer’s disease (AD). Endoplasmic reticulum (ER) stress has been implicated in the loss of neurons in AD. The phosphatase and tensin homolog deleted on chromosome ten (PTEN) plays an important role in regulating neuronal survival processes. However, the direct effects of the PTEN on ER stress and apoptosis in AD have not been elucidated. In this study, we demonstrate that the expression of PTEN and ER stress related proteins, GRP78 and CHOP, increased in APP/PS1 transgenic AD mice compared with WT mice. A PTEN inhibitor, dipotassium bisperoxo-(5-hydroxypyridine-2-carboxyl)-oxovanadate (bpv) could decrease apoptosis, induce AKT phosphorylation and inhibit the ER stress response proteins in hippocampus in APP/PS1 transgenic AD model mice. Furthermore, treatment with the specific PI3K inhibitor, LY294002, significantly blocked the anti-apoptotic effects of bpv in AD mice. The expression in GRP78, CHOP and apoptosis levels by bpv was reversed after PI3K inhibitor treatment. Taken together, our results indicate that the neuroprotective role of bpv involves the suppression of ER stress via the activation of the PI3K/AKT signalling pathways in APP/PS1 transgenic AD model mice.     

西双版纳地区降雨和食物资源可获得程度对犬蝠分娩时机的影响

繁殖是动物权衡不同自然选择压力和自身生理限制的结果。蝙蝠的繁殖受气候(温度、光周期和降雨量)和食物资源等非生物因素影响。本文通过野外调查犬蝠食物资源、设网捕捉和标志重捕的方法研究西双版纳地区降雨、食物资源可获得程度对犬蝠分娩时机的影响。研究发现,随着3 - 8 月降雨量逐渐增加(19.82 -41.13 kg/ m2 ),犬蝠取食的植物种类呈明显的增加趋势(4 - 9 种)。幼蝠捕捉量与植物资源可获得程度呈显著正相关关系(r = 0. 94,P = 0.01)。西双版纳犬蝠虽然具有一年两次动情和分娩的能力,但是绝大多数个体一年只分娩一次,且集中于3 -5 月。犬蝠分娩时机的选择使得幼蝠飞行学习和捕食时间与食物资源可获得程度高峰期相吻合,有利于提高幼体的生存适合度。     

即食型脱水蔬菜杀青、漂烫工艺初步研究

针对不同的即食型脱水蔬菜原料特性,进行前处理漂烫工艺研究。对蔬菜漂烫过程中营养成分的损失、酶活性的变化、褐变、护绿等多种因素进行综合考察,以获得了即食型脱水蔬菜漂烫最佳工艺参数。