温度胁迫对茶淡黄刺蛾四种保护酶活力和总抗氧化力的影响

【目的】温度适应性是决定昆虫分布和扩散的重要因素。为探索茶淡黄刺蛾Darna trima(Moore)对温度胁迫的耐受性,本研究测定了温度胁迫对4种抗氧化酶的活力和总抗氧化能力的影响。【方法】分别将茶淡黄刺蛾老熟幼虫置于﹣5、0、5、26(对照)、35、37.5、40℃下处理2、4、6 h,测定其体内超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、谷胱甘肽巯基转移酶(GST)和总抗氧化能力(T-AOC)的活力变化。【结果】茶淡黄刺蛾的4种抗氧化酶的活力和总抗氧化能力在不同温度和时间之间均存在显著变化,但不同指标对温度胁迫具有不同的响应模式。低温胁迫尤其是﹣5℃对各指标影响最为显著,而高温胁迫影响较小。【结论】SOD、CAT、POD、GST和T-AOC在茶淡黄刺蛾应对温度胁迫中具有重要作用,本研究可为判断茶淡黄刺蛾在茶区的分布范围提供一定的理论依据。     

甜菜碱对NaCl胁迫下小麦细胞保护酶活性的影响

本文以小麦为材料,研究甜菜碱对ＮａＣｌ胁迫下小麦幼苗细胞保护酶系统的影响。结果表明,外源甜菜碱能够提高ＮａＣｌ胁迫下小麦幼苗超氧化物歧化酶、过氧化物酶等细胞保护酶的活性,抑制过氧化作用产物丙二醛的积累,降低叶片质膜透性和盐害对细胞膜的伤害。所有这些变化都有利于提高ＮａＣｌ胁迫下小麦幼苗细胞膜的稳定性、完整性和对ＮａＣｌ胁迫的适应性     

共聚焦激光扫描显微镜活体观察动脉粥样硬化家兔模型大脑皮质血管内血液缘流厚度的改变

目的:探讨在兔脑皮层动脉粥样硬化时血管内缘流厚度的变化。方法:用共聚焦激光扫描显微镜比较家兔脑皮质动脉内缘流厚度在正常、粥样硬化病理状态下的不同。结果:在血管直径为74.87±3.26μm的血管中血液缘流厚度在病理状态下随血管的舒张、收缩而发生改变;而在血管直径为94.33±2.84μm的缘流厚度在血管收缩时发生改变。结论:动脉粥样硬化的家兔模型中血液缘流厚度随血液的流变性质改变而改变。     

Stability of domain 4 of the anthrax toxin protective antigen and the effect of the VWA domain of CMG2 on stability

The major immunogenic component of the current anthrax vaccine, anthrax vaccine adsorbed (AVA) is protective antigen (PA). We have shown recently that the thermodynamic stability of PA can be significantly improved by binding to the Von‐Willebrand factor A (VWA) domain of capillary morphogenesis protein 2 (CMG2), and improvements in thermodynamic stability may improve storage and long‐term stability of PA for use as a vaccine. In order to understand the origin of this increase in stability, we have isolated the receptor binding domain of PA, domain 4 (D4), and have studied the effect of the addition of CMG2 on thermodynamic stability. We are able to determine a binding affinity between D4 and CMG2 (～300 nM), which is significantly weaker than that between full‐length PA and CMG2 (170–300 pM). Unlike full‐length PA, we observe very little change in stability of D4 on binding to CMG2, using either fluorescence or ¹⁹F‐NMR experiments. Because in previous experiments we could observe a stabilization of both domain 4 and domain 2, the mechanism of stabilization of PA by CMG2 is likely to involve a mutual stabilization of these two domains.     

短期和长期运动预适应对力竭大鼠心肌损伤的保护作用

目的：研究短期和长期运动预适应对心肌细胞凋亡保护中发挥的作用及机制。方法：48只雄性SD大鼠随机分为对照组（C）、力竭组（E）、短期运动预适应组（S-EP）、长期运动预适应组（L-EP）。短期和长期运动预适应分别进行3 d和3周的反复间歇游泳训练方案。光镜下观察心肌细胞的结构改变;ELISA方法检测血清中缺血修饰白蛋白（IMA）、磷酸肌酸同工酶（CK-MB）含量;实时荧光定量PCR和Western blot方法检测心肌组织中TNF-α、Caspase-8、Caspase-3基因和蛋白表达;采用DNA原位末端标记（TUNEL）法观察心肌细胞的凋亡情况。结果：与C组相比,E组心肌细胞损伤严重,血清IMA、CK-MB含量及心肌组织中TNF-α、Caspase-8、Caspase-3 mRNA和蛋白表达升高（P<0.05）;与E组相比,S-EP组血清CK-MB及心肌TNF-α、Caspase-8mRNA明显降低（P<0.05）,而蛋白表达无统计学差异,血清IMA及Caspase-3 mRNA和蛋白均下降不明显,无统计学意义（P>0.05）,L-EP组血清IMA、CK-MB含量及心肌TNF-α、Caspase-8、Caspase-3 mRNA及蛋白明显降低,有统计学意义（P<0.05）;与S-EP组相比,L-EP组血清IMA、CK-MB含量及TNF-α、Caspase-8、Caspase-3 mRNA和蛋白明显下降,有统计学意义（P<0.05）。E组心肌细胞凋亡明显,S-EP组和L-EP组均能抑制凋亡,且L-EP组与S-EP组相比心肌凋亡明显减少。结论：短期和长期运动预适应均可减轻力竭后的心肌损伤,但短期运动预适应并未改变Caspase蛋白酶的表达,长期运动预适应明显抑制Caspase-8、3 mRNA表达,减少蛋白合成,从而发挥心肌保护效应,故长期运动预适应在抑制心肌细胞凋亡方面较短期运动预适应更强。     

Theoretical Investigation of 2D Layered Materials as Protective Films for Lithium and Sodium Metal Anodes

Rechargeable batteries based on lithium (sodium) metal anodes have been attracting increasing attention due to their high capacity and energy density, but the implementation of lithium (sodium) metal anode still faces many challenges, such as low Coulombic efficiency and dendrites growth. Layered materials have been used experimentally as protective films (PFs) to address these issues. In this work, the authors explore using first‐principles computations the key factors that determine the properties and feasibility of various 2D layered PFs, including the defect pattern, crystalline structure, bond length, and metal proximity effect, and perform the simulations on both aspects of Li⁺ (Na⁺) ion diffusion property and mechanical stability. It is found that the introduction of defect, the increase in bond length, and the proximity effect by metal can accelerate the transfer of Li⁺ (Na⁺) ion and improve the ionic conductivity, but all of them make negative influences on the stiffness of materials against the suppression of dendrite growth and weaken both critical strains and critical stress. The results provide new insight into the interaction mechanism between Li⁺ (Na⁺) ions and PF materials at the atomic level and shed light onto exploring a variety of layered PF materials in metal anode battery systems.     

文县疣螈资源现状、威胁因素及保护对策

文县疣螈Tylototriton wenxianensis分布在文县、平武、青川、阆中、奉节和雷山,但只有文县、青川、平武3县相连成片,为岷山栖息地,面积约1800km2,数量约30000条。文县疣螈对海拔1000～1400m的潮湿陆地森林或泥底的水域环境选择较强,以森林或林缘地带积水不深、植被良好、基底多泥的小水塘为繁殖发育场所。文县疣螈面临茶园扩张、薪柴、干旱和分布区狭窄的威胁。调整茶叶发展战略,加强林地保护,推动茶叶集约化加工,研制并推广小型节能炒茶炉,人工增建小泥塘,保护和扩大最适栖息地,资助社区保护组织是缓解这些威胁的有效对策。     

虫酰肼及其衍生物0593对家蚕的毒性及作用机理

为明确虫酰肼衍生物0593对家蚕Bombyx mori的毒性,本研究采用食下毒叶法测定了虫酰肼及其衍生物0593对家蚕的毒性,观察了亚致死浓度下对家蚕生长发育的影响,并测定了虫酰肼及其衍生物0593对家蚕幼虫体内保护酶的影响,对虫酰肼0593的作用机理进行了初步探索。结果表明：虫酰肼及其衍生物0593对2龄家蚕96 h的LC₅₀值分别为1.2863和0.3364 mg·L^-1,属高毒级药剂;虫酰肼及其衍生物0593在亚致死剂量下对家蚕的生长发育有明显的不利性,可使幼虫历期缩短0.5～2 d;处理组眠期体重、全茧量、蛹重和化蛹率与对照相比均显著降低;对4龄幼虫体内多酚氧化酶和几丁质酶也有较明显影响,虫酰肼及其衍生物0593处理家蚕,处理后6 h对体内多酚氧化酶有明显激活作用,12 h后表现出显著的抑制作用;虫酰肼及其衍生物0593对家蚕体内几丁质酶均有激活作用。0593对保护酶的影响较虫酰肼明显。结果提示虫酰肼及其衍生物0593对家蚕毒性高,对其生长发育和保护酶类均有不利性,不适合在桑园及其周边农田使用。     

Ca2+对铬胁迫下木麻黄种子萌发的生态效应

研究不同浓度Ca2 + 对铬胁迫下木麻黄种子萌发的影响。结果表明 ,在 10mgCr3 + ·L-1或 10 0mgCr3 + ·L-1胁迫下 ,木麻黄种子萌发及幼苗生长发育受到抑制 ,较高浓度的Cr3 +显示更大的毒性效应 ;在加入适量Ca2 + 处理后 ,植物虽仍处在铬胁迫下 ,但脯氨酸、O-2 、MDA含量以及POD、CAT活性有所下降 ,SOD活性上升 ,缓解了铬对种子萌发的抑制和幼苗生长发育的影响。Ca2 + 表现出对铬胁迫下木麻黄种子萌发和幼苗膜保护酶活性有积极的调控作用 ,且可调节脯氨酸应激反应的灵敏程度 ,降低活性氧的产生速率和膜脂过氧化程度 ,但Ca2 + 处理需要适当的浓度 ,浓度过高会产生负效应。Ca2 + 调控的最适浓度为 0 0 1～ 1mmol·L-1。     

The 3MRA Risk Assessment Framework—A Flexible Approach for Performing Multimedia,Multipathway, and Multireceptor Risk Assessments Under Uncertainty

A flexible framework for conducting nationwide multimedia, multipathway and multireceptor risk assessments (3MRA) under uncertainty was developed to estimate protective chemical concentration limits in a source area. The framework consists of two components: risk assessment and uncertainty analysis. The risk component utilizes linked source, fate/transport, exposure and risk assessment models to estimate the risk exposures for the receptors of concern. Both human and ecological receptors are included in the risk assessment framework. The flexibility of the framework is based on its ability to address problems varying in spatial scales from site-specific to regional and even national levels; and its ability to accommodate varying types of source, fate/transport, exposure and risk assessment models. The uncertainty component of the 3MRA framework is based on a two-stage Monte Carlo methodology. It allows the calculation of uncertainty in risk estimates, and the incorporation of the effects of uncertainty on the determination of regulatory concentration limits as a function of variability and uncertainty in input data, as well as potential errors in fate and transport and risk and exposure models. The framework can be adapted to handle a wide range of multimedia risk assessment problems. Two examples are presented to illustrate its use, and to demonstrate how regulatory decisions can be structured to incorporate the uncertainty in risk estimates.