黑鲷ELO基因编码蛋白结构与功能的生物信息学分析

黑鲷是一种抗逆性强的海水经济鱼类,但在长江以北无法在室外自然越冬,每年进行室内越冬又耗时耗力。为了培育黑鲷耐低温品系,探究黑鲷低温耐受的分子机制,研究了黑鲷脂肪酸延长酶（fatty acid elongase,ELO）基因编码蛋白的结构和功能。首先,运用DNAman 8软件对黑鲷、金头鲷、鱖鱼、斜带石斑鱼、鲤鱼等5种鱼类的ELO蛋白进行氨基酸序列比对,分析其同源性和进化关系;随后,利用生物信息学工具对黑鲷ELO蛋白的理化性质、亚细胞定位、信号肽、跨膜区、剪切位点、蛋白磷酸化、糖基化、二级结构、结构域、分子功能及蛋白质相互作用等进行分析,并进行同源建模与三维结构预测。氨基酸序列比对结果显示,黑鲷与其他鱼类之间序列的同源性较高,在所分析的5种鱼类中,黑鲷与金头鲷亲缘关系最近,与鲤科鱼类亲缘关系最远。生物信息学分析结果表明,ELO蛋白为碱性、小分子、稳定、非分泌型亲水蛋白质,亚细胞定位于细胞质、细胞核和线粒体;该蛋白质中存在22个剪切位点、19个磷酸化位点和 9个赖氨酸糖化作用位点,没有糖基化位点和信号肽;其包含多种二级结构,其中以α-螺旋为主,存在1个结构域及7个跨膜区域;ELO蛋白与其他10个蛋白质可能存在直接的相互作用关系,有可能影响雌激素合成。通过对黑鲷ELO基因编码蛋白结构与功能的生物信息学分析,初步判定其与低温耐受相关。研究结果为黑鲷耐低温品系选育提供了基础理论依据。     

不同来源家蝇幼虫蛋白粉的水解与抗氧化性

本研究比较不同来源、不同酶解物浓度的家蝇幼虫蛋白及其抗氧化活性。以来自猪粪源和鸡粪源家蝇幼虫为原料制备蛋白粉,用胰蛋白酶水解蛋白粉制备水解产物,以·OH和O_2~-·清除率为指标评价两种蛋白酶解物的抗氧化活性。结果显示,家蝇幼虫蛋白水解物在4 h达水解度最高值,其水解物的·OH清除率在5 h达到最大为59.02%,其水解物的O_2~-·清除率在4 h达到最大为73.24%;随着两种水解物浓度增加,其抗氧化效果越强,当猪粪源和鸡粪源家蝇幼虫酶解物浓度为10 mg/mL时,两者O_2~-·清除率达到最大分别为70%和80%;·OH清除率分别为45%和52%。由此可见,家蝇幼虫酶水解物对超氧阴离子、羟自由基均有清除能力,鸡粪源家蝇幼虫酶解物优于猪粪源。     

悬铃木方翅网蝽发生为害调查与防治

悬铃木方翅网蝽是一种外来入侵害虫,该虫近几年在石家庄发生普遍,为害严重.调查了悬铃木方翅网蝽在石家地区的寄主植物、为害特点和发生规律,观察描述了其形态特征、生活史和生活习性,测试分析了树冠喷施不同药剂对悬铃木方翅网蝽的防效.     

纳米硒对岢岚绒山羊妊娠母羊及胎儿抗氧化性、硒蛋白表达及生长发育的影响

为研究纳米硒对岢岚绒山羊妊娠母羊及胎儿抗氧化能力、硒蛋白表达和生长发育的影响。选择体重相近的岢岚妊娠绒山羊80只,随机分为2组,分别喂以基础日粮和添加0.5mg/kg DM纳米硒的饲粮,实验期110d。结果表明:日粮中纳米硒的添加极显著(P<0.01)地提高了母羊及胎儿血清中GSH-Px、SOD的活性;极显著(P<0.01)提高了母羊及胎儿肝、胎盘组织中GSH-Px、SOD的活性;极显著(P<0.01)降低了母羊及胎儿血清与胎盘组织中MDA的浓度。在日粮中添加纳米硒后,母羊及胎儿肝、肾组织中cGPx1 mRNA的表达显著提高(P<0.05);胎盘组织中的cGPx、SeP、Trx1 mRNA的表达极显著提高(P<0.01)。妊娠母羊的基础日粮中加入纳米硒,极显著(P<0.01)提高了妊娠母羊及胎儿血清、肝、胎盘组织中IGF-1的含量和IGF-1mRNA表达量,显著增加了胎盘、胎儿及胎儿肝、肾组织的重量(P<0.05)。日粮中添加0.5mg/kg DM纳米硒,增强了妊娠母羊及胎儿的抗氧化能力,提高了IGF-1、cGPx1、SeP和Trx1 mRNA的表达量,进一步促进了胎儿的生长发育。     

Hydraulic failure and tree dieback are associated with high wood density in a temperate forest under extreme drought

Catastrophic hydraulic failure will likely be an important mechanism contributing to large‐scale tree dieback caused by increased frequency and intensity of droughts under global climate change. To compare the susceptibility of 22 temperate deciduous tree and shrub species to hydraulic failure during a record drought in the southeastern USA, we quantified leaf desiccation, native embolism, wood density, stomatal conductance and predawn and midday leaf water potential at four sites with varying drought intensities. At the two driest sites, there was widespread leaf wilting and desiccation, and most species exhibited predawn leaf water potentials of ≤3 MPa and >60% loss of xylem conductivity in branches. Although species with high wood density were more resistant to cavitation, they had higher levels of native embolism and greater canopy dieback than species with low wood density. This unexpected result can be explained by the failure of species with dense wood to avert a decline in water potential to dangerous levels during the drought. Leaf water potential was negatively correlated with wood density, and the relationship was strongest under conditions of severe water deficit. Species with low wood density avoided catastrophic embolism by relying on an avoidance strategy that involves partial drought deciduousness, higher sensitivity of stomata to leaf water potential and perhaps greater rooting depth. These species therefore maintained water potential at levels that ensured a greater margin of safety against embolism. These differences among species may mediate rapid shifts in species composition of temperate forests if droughts intensify due to climate change.     

Reduced N cycling in response to elevated CO2, warming,and drought in a Danish heathland: Synthesizing results of the CLIMAITE project after two years of treatments

Field‐scale experiments simulating realistic future climate scenarios are important tools for investigating the effects of current and future climate changes on ecosystem functioning and biogeochemical cycling. We exposed a seminatural Danish heathland ecosystem to elevated atmospheric carbon dioxide (CO₂), warming, and extended summer drought in all combinations. Here, we report on the short‐term responses of the nitrogen (N) cycle after 2 years of treatments. Elevated CO₂ significantly affected aboveground stoichiometry by increasing the carbon to nitrogen (C/N) ratios in the leaves of both co‐dominant species (Calluna vulgaris and Deschampsia flexuosa), as well as the C/N ratios of Calluna flowers and by reducing the N concentration of Deschampsia litter. Belowground, elevated CO₂ had only minor effects, whereas warming increased N turnover, as indicated by increased rates of microbial NH₄⁺ consumption, gross mineralization, potential nitrification, denitrification and N₂O emissions. Drought reduced belowground gross N mineralization and decreased fauna N mass and fauna N mineralization. Leaching was unaffected by treatments but was significantly higher across all treatments in the second year than in the much drier first year indicating that ecosystem N loss is highly sensitive to changes and variability in amount and timing of precipitation. Interactions between treatments were common and although some synergistic effects were observed, antagonism dominated the interactive responses in treatment combinations, i.e. responses were smaller in combinations than in single treatments. Nonetheless, increased C/N ratios of photosynthetic tissue in response to elevated CO₂, as well as drought‐induced decreases in litter N production and fauna N mineralization prevailed in the full treatment combination. Overall, the simulated future climate scenario therefore lead to reduced N turnover, which could act to reduce the potential growth response of plants to elevated atmospheric CO₂ concentration.     

壳聚糖微球分散体系的抑菌性研究

以乳化交联法制备的壳聚糖微米微球(CMs)为试验材料,研究其对金黄色葡萄球菌和大肠杆菌的抑菌行为,并对其浓度因素、粒径因素和抑菌机理做了探讨。结果表明CMs的抑菌作用随其浓度的增加和粒径的减小而增强。在浓度<0.7 mg/mL时,CMs对细菌的生长具有先抑制后促进的作用;当浓度≥0.7 mg/mL时对细菌有杀灭作用。CMs对两种细菌的最小抑菌浓度和最小杀菌浓度分别为0.8、1.4 mg/mL和1.0、1.8 mg/mL,表明壳聚糖微球对金黄色葡萄球菌和大肠杆菌均具有明显的抑制作用,且金黄色葡萄球菌对微球抑制作用的反应比大肠杆菌更敏感。扫描电子显微镜观察发现,细菌能迅速贴附在CMs表面,并且贴壁后的细菌发生了明显的形态变化,有的甚至完全被破坏。     

胆道肿瘤动物模型建立的研究现状

胆管癌是一种侵袭性很强的胆道恶性肿瘤,全世界的发病率和死亡率逐步增加。建立合适的胆管癌动物模型对胆管癌的早期诊断和治疗具有重要意义。本文就胆道肿瘤动物模型建立方法的现状进行综述。     

3种药赏两用植物对滨海盐碱土改良效应的比较

为比较种植药赏两用植物对滨海盐碱土的改良效应,采用实生栽培方法种植了薄荷(Mentha haplocalyxBriq.)、地榆(Sanguisorba officinalis L.)和枸杞(Lycium chinense Mill.)1年生植株,对不同土层的pH值以及可溶性盐和主要离子含量的变化进行了比较分析。结果表明:种植3种植物后,0～10、10～20和20～30 cm土层的pH值以及可溶性盐、K+、Na+、Ca2+、Mg2+、Cl-和SO42-含量均有不同程度的变化,且以0～10 cm土层的变化相对明显,并且各土层的离子组成也有所改变。种植3种植物后,0～10和10～20 cm土层的pH值以及0～10 cm土层的可溶性盐含量均低于对照,其中,地榆种植土壤pH值及枸杞种植土壤可溶性盐含量的降低效应最明显。种植3种植物后,各土层的Ca2+含量及10～20和20～30 cm土层的K+和Mg2+含量均极显著高于对照,各土层的Na+含量及0～10 cm土层的Cl-含量、10～20和20～30 cm土层的SO42-含量均极显著低于对照;不同土层的K+/Na+值均高于对照、(K++Na+)/(Ca2++Mg2+)值均低于对照、主要阳离子(Ca2+、K+和Mg2+)的交换量总和均明显增加。总体上,地榆和枸杞对土壤中K+及Ca2+和Mg2+含量、K+/Na+值、主要阳离子(Ca2+、K+和Mg2+)交换量总和的提高效应以及对Na+含量、(K++Na+)/(Ca2++Mg2+)值的降低作用均较强,而薄荷的作用均较弱。研究结果显示:供试的3种药赏两用植物对盐碱地均具有明显的改良作用,其中枸杞和地榆的改良效果较好。     

地锦粗提物对脾虚小鼠脏器指数和抗氧化能力的影响

目的探讨地锦粗提物对脾虚小鼠脏器指数和抗氧化能力的影响,为防治脾虚提供参考。方法 30只昆明小鼠随机分成3组,每组10只,即对照组、脾虚组和地锦组。脾虚组和地锦组采用泻下加劳倦方法,灌服大承气汤30 g/(kg.d),并负重游泳,对照组灌服生理盐水30 g/(kg.d),不游泳,持续60 d,然后灌胃60 d,地锦组灌胃地锦水醇浸出液30 g/(kg.d),脾虚组和对照组给予相当剂量的生理盐水。实验结束后取心、肝、脾、肺、肾,称重并计算脏器指数,测血浆过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)活力,测心、肝、脾、肺、肾中超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量。结果脾虚组心指数和肺指数极显著增加,左肾指数显著增加,地锦组心指数显著增加。地锦组的血浆CAT和GSH-Px活力显著高于脾虚组,地锦组肝和脾中的SOD活力显著高于脾虚组,地锦组脾、肺MDA含量显著低于脾虚组。结论地锦粗提物可降低脾虚小鼠的脏器指数,并可提高脾虚小鼠抗氧化能力。