An improved method for extraction of sorghum polymeric protein complexes

A method for fractionating sorghum proteins using extraction solvents and techniques designed to obtain polymeric protein structures (especially disulfide linked) was developed. Extraction and separation conditions were optimized in terms of completeness of protein extraction, sample stability, and analytical resolution. After pre-extraction of albumins and globulins, a 3-step sequential procedure involving no reducing agents was applied to ground whole sorghum flour. The three fractions obtained represented proportionally different protein polymer contents and molecular weight distribution as evidenced by comparative size exclusion chromatography. Protein composition also varied among the extracts with differences in kafirin composition and non-kafirin proteins detected in the fractions by RP-HPLC and SDS-PAGE analysis. The ability to quantify and further characterize sorghum polymeric protein complexes will be useful for additional studies linking protein structures with functionality and digestibility and variations for these properties within diverse sorghum germplasm.     

紫茉莉茎提取物及其萃取物对菜粉蝶幼虫的生物活性

用饲喂法、叶片夹毒法、叶磲法测定了紫茉莉茎的3种极性溶剂(石油醚、氯仿和乙醇)提取物及萃取物对菜粉蝶幼虫的毒杀活性、胃毒作用、非选择性拒食活性.结果表明,紫茉莉茎氯仿提取物的毒杀与拒食效果最好,处理第5天后的校正死亡率为89.20%.取食第3天与第5天的拒食率分别为96.80%与99.67%;也测定了紫茉莉茎氯仿提取物(简称MSCE)各萃取物(正己烷、氟仿和水萃取物)对4龄菜粉蝶幼虫的生物活性.结果表明,MSCE的正己烷萃取物第5天与第7天的毒杀效果最好,其校正死亡率分别为79.80%与78.90%;其对4龄菜粉蝶幼虫的胃毒作用明显的强于其他各萃取物.     

Transgenic sorghum with suppressed synthesis of kafirin subclasses: Effects on flour and dough rheological characteristics

Arising from work showing that conventionally bred high protein digestibility sorghum types have improved flour and dough functionality, the flour and dough properties of transgenic biofortified sorghum lines with increased protein digestibility and high lysine content (TG-HD) resulting from suppressed synthesis of several kafirin subclasses, especially the cysteine-rich γ-kafirin, were studied. TG-HD sorghums had higher flour water solubility at 30 °C (p < 0.05) and much higher paste viscosity (41% higher) than their null controls (NC). TG-HD doughs were twice as strong as their NC and dynamic rheological analysis indicated that the TG doughs were somewhat more elastic up to 90 °C. CLSM of doughs and pastes indicated that TG-HD had a less compact endosperm protein matrix surround the starch compared to their NC. The improved flour and dough functional properties of the TG-HD sorghums seem to be caused by reduced endosperm compactness resulting from suppression of synthesis of several kafirin subclasses which modifies protein body and protein matrix structure, and to improved protein-starch interaction through hydrogen bonding specifically caused by reduction in the level of the hydrophobic γ-kafirin. The improved flour functionality of these transgenic biofortified sorghums can increase their commercial utility by complementing their improved nutritional quality.     

烟草蛋白研究进展

从烟草中提取烟草蛋白,是解决目前动物蛋白紧缺问题的有效途径之一。介绍了烟草蛋白的组成与特性,分析了烟叶作为蛋白来源的潜力,综述了国内外烟草蛋白分离纯化技术的研究进展,讨论了影响烟草蛋白制备的主要因素,并对烟草蛋白的开发利用进行了展望。     

红蓼种子萃取物对黏虫的作用机理

测定了红蓼种子乙酸乙酯萃取物对黏虫5龄幼虫体内5种酶活性的影响,结果表明,红蓼种子乙酸乙酯萃取物对黏虫幼虫体内Na+-K+-ATP酶的活性具有一定的抑制作用,而对其他几种酶活性没有明显作用。     

数字图像估测棉花光合有效辐射吸收比例

研究利用数字图像技术估测棉花光合有效辐射吸收比例的方法,以期为棉花生长状况的动态监测提供依据。2013-2014年设置不同株行距配置试验,在棉花关键生育时期通过数码相机、线性光量子传感器分别测定棉花覆盖度和光合有效辐射吸收比例。结果表明,不同配置方式下,fCover和fAPAR的季节变化规律基本一致,生育后期由于非绿色器官的增多致使低估fCover;fCover与fIPAR和fAPAR呈线性的极显著正相关,与LAI和干物质呈指数的极显著正相关;综合分析2a数据,建立图像覆盖度估测fAPAR的模型(R2=0.895,SE=0.076);根据独立试验数据对估测模型进行检验的结果显示,模型的决定系数(R2=0.964)较高且预测误差(RMSE=0.058)较小。因此,图像覆盖度是一种简便、快捷、有效地估测棉花光合有效辐射吸收比例的方法。     

三江平原典型湿地土壤腐殖质的剖面分布及其组成特征

以三江平原腹地挠力河、别拉洪河、浓江河流域自然沼泽湿地为研究对象,研究了典型湿地土壤腐殖质的剖面分布及其组成特征,并探讨了土壤腐殖质与植被类型及土壤全氮含量的关系。三江平原典型湿地土壤草根层和泥炭层中胡敏酸(HA)和富里酸(FA)的累计含量在整个剖面总量中的比例均大于70%,各组分相对含量分别高于35%总有机碳和23%总有机碳,其剖面分布与土壤有机碳(SOC)的变化趋势一致,由表层向下层逐渐减少。除小叶章湿地土壤草根层HA/FA值为0.97外,三江平原典型湿地土壤HA/FA均大于1,其剖面均值为1.4~2.5,表明三江平原湿地为胡敏酸型土壤.腐殖质各组份含量及其HA/FA值因植被类型而异,而与土壤全氮含量呈显著线性相关(p<0.05)。     

不同类型菜田和农田土壤磷素状况研究

以西北地区有代表性的灌淤土为供试土壤,研究不同类型菜田(露地菜田和蔬菜保护地)及农田土壤的P素状况,以及蔬菜保护地土壤P素的空间分布特性。结果表明,露地菜田、蔬菜保护地土壤全P、无机P、有机P、Olsen-P的平均含量是一般农田土壤的1.43~8.30倍,土壤Olsen-P占全P的比率显著高于一般农田。蔬菜保护地土壤各形态P素主要积累在0~30cm土层,并随土层深度的增加各形态P素的含量逐渐降低,各土层Olsen-P、Ca2-P、Ca8-P、Al-P含量降低幅度明显高于Fe-P、O-P、Ca10-P。     

Incorporation of 14CO2 and 15NH4 into amino acids of the two subunits of fraction 1 protein in spinach leaves

In the investigation of nitrogen metabolism in plants, it is important to deal with proteins, which are the end-products of nitrogen metabolism.