氨基酸转运载体的研究进展

氨基酸转运载体是介导氨基酸跨膜转运的膜蛋白,在医学、营养等生命科学领域有着重要的研究意义。本文就氨基酸转运载体家族成员及组织分布,生物学特征、生理功能和影响因素等方面进行了综述。     

不同施镁水平对烤烟干物质积累及烟碱含量的影响

[目的]研究不同施镁水平对烟草生育期干物质积累及烟碱含量的影响。[方法]试验共设4个处理：不施镁肥（对照）;低镁处理（150kg/hm2）;中镁处理（300kg/hm2）;高镁处理（450kg/hm2）,其中镁用量为MgSO4.7H2O肥料量。[结果]不同生育期烟草叶片内镁含量均随着施镁量的增加而提高。在旺长期和成熟期,随着施镁量增加,叶片积累的干物质量越多。随着施镁水平的增加,烟叶中烟碱含量逐步下降,其中对下部叶片烟碱含量影响较小,对中部叶片烟碱影响居中,对上部叶片烟碱影响最大。[结论]该研究为烟叶生产上合理施肥、改善烟株营养状况、提高烟叶的产量和品质提供了科学依据。     

牛阴离子交换蛋白1和生电碳酸氢钠协同转运蛋白亲水结构域的克隆·表达和纯化

[目的]表达和纯化牛阴离子交换蛋白1（AEl）和生电碳酸氢钠协同转运蛋白（NBCel）的亲水结构域。[方法]根据AE1和NBCel的亲水结构域设计引物,通过PCR扩增牛AE1和NBCel的亲水结构域,通过原核表达系统,以E．coli BL2l（DE3）为表达宿主,经IPTG诱导,表达重组的牛AE1和NBCel的亲水结构域融合蛋白,并采用金属螯合层析法对目的蛋白进行纯化。15％SDS—PAGE分析目的蛋白的表达、分布和纯度。[结果]PCR扩增了牛AE1和NBCel的亲水结构域;IPTG诱导后,成功的表达了目的蛋白;目的蛋白主要存在大肠杆菌的胞浆中,可以被较好的纯化。[结论]牛AE1和NBCel的亲水结构域蛋白的表达为制备抗体和研究膜载体蛋白的调节机理提供了条件。     

板栗脂质转运蛋白基因的克隆及表达

利用RACE技术从板栗短雄花序突变体中扩增得到660bp的板栗脂质转运蛋白(lipid transfer protein,LTP)cDNA片段。该cDNA编码118个氨基酸,具有8个位置保守的半胱氨酸(C)残基及26个氨基酸的信号肽,它与棉花、草莓脂质转运蛋白氨基酸序列相似性为63%,基因序列已提交数据库(GenBank),其登录号分别为FJ490676(基因)和ACL01093(蛋白)。荧光定量分析表明板栗短雄花序突变体较正常雄花序的脂质转运蛋白表达量更高。将板栗脂质转运蛋白基因插入到硫氧还蛋白融合表达载体pET32a(+)中,构建了板栗的原核表达载体pET-LTP,在大肠杆菌菌株Rosetta-gamiTM2(DE3)中,IPTG诱导5h大量表达约为30ku的融合蛋白,通过Ni2+-chelating sepharose fast flow柱纯化的融合蛋白具有抑制板栗镰刀菌属病原真菌孢子萌发的功能。     

水稻盐胁迫应答的分子机制

水稻是一种对盐胁迫中度敏感的作物,它的耐盐性反应是个复杂的过程,包括对外界盐信号的感知和传递、特异转录因子的激活和下游胁迫应答基因的表达。综述了负责维持和重建离子平衡的Na+转运蛋白、转录调控因子和渗透调节基因的功能。它们的作用结果,或通过将盐离子隔离进液泡,或排出体外,或在胞质中积累大量渗透调节物质,最终使得植株表现耐盐性。     

陇中半干旱区集雨限灌对马铃薯干物质积累和产量的影响

研究了大田条件下集雨有限补偿灌溉对旱区马铃薯干物质积累分配和产量的影响。结果表明:进行有限补充灌溉对旱作马铃薯有显著的增产效果,其经济系数也得到相应提高,与对照(不灌水)相比,补灌处理产量增幅在3.91%~21.21%之间,苗期补灌45 mm与90 mm对马铃薯产量的补偿效应显著;补灌马铃薯干物质积累量与对照相比无显著差异,但花后干物质的分配运转,苗期补灌处理比对照移动量大,转换率高,有利于花后薯块营养物质的积累;薯块膨大期补灌45 mm和90 mm,在干物质积累和花后干物质转化方面均低于对照,增产效果也并不显著。     

Tillage and Poultry Manure Effects on Soil Physical Properties,Nutrient Status,Growth, Dry Matter and Grain Yield of Sorghum

The effects of different tillage systems and poultry manure on soil physical properties, performance and nutrients in sorghum were studied for three years at Owo, southwest Nigeria. There was factorial combinations of herbicide-based zero tillage （ZT）, manual clearing （MC）, disc ploughing （P）, ploughing plus harrowing （P＋H） and ploughing plus double harrowing （P＋2H）, and two rates of poultry manure at 0 and 7.5 Mg ha^-1. Herbicide-based zero tillage and manual clearing reduced soil temperature and conserved more water than mechanized tillage techniques. Poultry manure reduced soil bulk density and temperature and increased soil water and porosity. There was a percentage decrease of leaf N, P, K, Ca and Mg concentrations, plant height, leaf area, stem girth, root dry weight, dry matter and grain yield in ascending order for herbicide-based zero tillage, manual clearing, ploughing, ploughing plus harrowing and ploughing plus double harrowing while percentage increases were recorded in a descending order for all the various combinations of tillage with poultry manure in that order. Poultry manure in combination with tillage increased dry matter and grain yield by 33.1 and 39.5%, respectively in comparison with tillage only. The manure-zero tillage methods increased dry matter and grain yield by 8% and 15%, respectively when compared with manure-mechanized tillage methods. Zero tillage or manual clearing in combination with 7.5 Mg ha^-1 poultry manure was most suitable for sorghum cultivation.     

银杏GGPPS转运肽与GFP融合基因表达载体的构建（摘要）

[目的]构建银杏GGPPS转运肽与GFP融合基因表达载体。[方法]以银杏为材料,采用DNA重组技术克隆GGPPS基因质体转运肽（TP）序列,并将其与高效植物表达载体p1304＋连接形成融合表达载体（p1304＋-TP）;冻融法转化根瘤农杆菌EHA105,构建工程菌（EHA105-p1304＋-TP）。[结果]成功构建了银杏GGPPS转运肽与GFP融合基因表达载体及农杆菌工程菌。[结论]为进一步研究TP转运肽的亚细胞定位奠定基础,有助于阐明银杏内酯前体生物合成关键步骤的分子机理,同时为银杏内酯的代谢工程研究提供重要依据。     

Effect of Nutrient Type on Chemical Composition and Dry Matter Partitioning of Cassava （Manihot esculenta Crantz）

The objective of our study was to determine the effects of four types of fertilisers enrichments （manure potassic （K）, phosphatic （P）, phosphatic and potassic （PK） and nitrogenized, phosphated and potassic （NPK）） on chemical composition and dry matter in cassava （Manihot esculenta） organs （clone 1171） during harvest period. The pots experiment was laid out in randomised complete bloc design with five treatments and four replications. Water, nitrogen, potassium, phosphorus, sodium, total proteins and total lipids contents of the leaves, shoots and tubers were determined. After 9 months growing period, results showed that fertilizer types enriched with K, PK and NPK significantly increased the organic compounds contents of the leaves （P〈0.05）. Furthermore, fertilizers with high phosphorus content significantly increased the lipid contents of the leaves （25%）. Fertilizers enriched with NPK positively influenced the biomass partitioning in Manihot esculenta. Application of fertilizers enriched with NPK led to higher levels of total proteins in the leaves and tubers （70 mg g DM^-1 and 30 mg g DM^-1 respectively） compared to control （17 mg g DM^-1 and 9 mg g DM^-1 respectively）. These results help to demonstrate the value of these fertilizers enrichment to improve the chemical composition and dry matter partitioning of cassava.     

Dynamic Simulating to the Accumulation and Distribution of Dry Matter for Black Walnut （Juglans hindsii） Seedlings

It is very important to study eco-physiological processes of plants and to determine quantitative relations between accumulation, distribution of dry matter and environmental factors for regionalization, standardization and precision agriculture. Meanwhile, global changes, e.g., atmospheric CO2 concentration rising, global warming, and climate abnormity, have been effecting on agricultural productivity. This study provides a theoretical basis for predicting productive potentials and development trends in different agricultural regions. One-year-old black walnut （Juglans hindsii） seedlings were employed as subjects for setting up the dynamic models of dry matter accumulation and distribution, based on mechanistic models of photosynthesis, matter conservation and concentration gradient. Under optimum conditions of soil moisture and mineral nutrient, during the period of the canopy construction, the dry matter accumulation of the canopy conformed to logistic curves; but the accumulation of both total biornass and dry matter of stem-root could be divided into two phases： the first phase was exponential increase, the second was linear increase. The total biomass, dry matter of canopy and stem-root all presented a fluctuant increase, which was affected by the environmental factors. Ratio of daily increase of dry matter in the canopy and the steem-root （dWJdWs） was changeable along with growth periods and environmental factors. At the initial stage of the canopy forming, dW/dWs was larger, about 3.2 on average, which indicated that the photosynthetic product was mainly used to develop leaves; in the midterm, it was about 1.9, which indicated that the distribution of dry matter in the canopy and in the stem-root was relatively balanced; when the plant tended to stop growing, dWl/dWs decreased linearly, and the main distribution of dry matter moved to the roots.