Comparison of the conformational and nutritional changes of deamidated wheat gliadin by citric acid and hydrochloric acid

Deamidated wheat gliadins were prepared using hydrochloric acid (HCl) and citric acid (HDWG and CADWG), respectively. Their secondary structure, protein molecular interaction, thermal properties and nutritional changes were compared by Fourier transform infrared spectroscopy (FTIR), Raman spectrum, atomic force microscopy (AFM), differential scanning calorimetry (DSC), and amino acid analysis, respectively. Secondary structures and molecular vibration model showed slight difference between HDWG and CADWG, but significant difference between control gliadin and deamidated wheat gliadins. HDWG and CADWG had different shapes on the mica surface that the former showed some extent of linear aggregates and fibrils while the latter mainly exhibited globular aggregates. This result was further supported by thermal characteristics that CADWG had higher denaturation temperature than control gliadin and HDWG. Citric acid deamidation could increase the Lysine content and better maintain the total essential amino acids of in vitro digests of gliadin compared with HCl.     

拟鹅观草属植物的醇溶蛋白研究

利用酸性聚丙烯酰胺凝胶电泳 (A -PAGE)对小麦族拟鹅观草属 2 2份材料和鹅观草属 5份材料进行醇溶蛋白遗传分析 ,结果表明 :① 2 7份材料共分离出 2 6条带纹 ,多态性高达 10 0 % ;②拟鹅观草属植物具有较丰富的醇溶蛋白多态性 ,其种间和种内不同居群间均存在明显的醇溶蛋白遗传变异 ,且种间变异大于种内变异 ,醇溶蛋白图谱可以作为鉴定拟鹅观草属植物的指纹图谱 ;③醇溶蛋白图谱的聚类结果与形态学、细胞学和RAPD研究结果基本一致 ,表明醇溶蛋白资料可以运用于拟鹅观草属植物种间、种内遗传差异及系统关系研究。     

小麦抗赤霉病突变体的选育及其变异研究

利用辐射与离体培养,细胞筛选相结合的方法进行抗病突变体的筛选,选育出４个抗赤霉病的突变体,经多年田间接种鉴定和考察,突变体的抗病能力较亲本提高１～２级,株高,穗长和小穗数等主要农艺性状也发生了变异。突变体与其亲本相比,醇溶蛋白电泳和过氧化物同工酶酶谱带数,谱带强度和谱带位置都有差异,超氧化物歧化酶的活性分析表明,在毒素作用下,突变体的酶活性比亲本高８．６１％～２４．１４％,突变体具有较高的超氧化物     

小麦骨干亲本碧蚂4号及其衍生品种的醇溶蛋白组成分析

为了揭示小麦骨干亲本醇溶蛋白组成的遗传演化规律,利用酸性聚丙烯酰胺凝胶电泳(A-PAGE)技术,对骨干亲本碧蚂4号衍生系谱共98个品种(系)的醇溶蛋白组成进行分析。结果表明,碧蚂4号有16条醇溶蛋白谱带,与系谱涉及的中间亲本相比,碧蚂4号的Gli64.5(β区)是其特有条带,遗传到衍生后代品种(系)的频率达到11.3%;碧蚂4号在α区的Gli81.7和Gli74.3、β区的Gli66.9和Gli62.2、γ区的Gli56.7和Gli47.7以及ω区的Gli18.9和Gli16.7共8条带均在系谱4个世代呈现高频率遗传趋势,频率为59.0%~100.0%,进一步分析发现,碧蚂4号衍生品种(系)系谱中涉及的多数中间亲本与碧蚂4号具有相同迁移率的谱带,表明育种过程中这些谱带被不断地补充进来;γ区的Gli52.3和ω区的Gli33.0、Gli30.0、Gli28.1、Gli20.9均只在碧蚂4号衍生的个别世代品种(系)中占主导地位,这可能与不同时期育种目标的变化有关。以上分析说明,育种选择对醇溶蛋白演变起到非常重要的作用。     

山羊草属植物醇溶蛋白的遗传多样性分析

利用APAGE技术对山羊草属中6个物种30份材料的醇溶蛋白进行了分析,共出现14种醇溶蛋白APAGE谱带类型和67条相对迁移率不同的谱带,其中,每份材料可分离出10~22条带,所有67条谱带均具有多态性。同一物种内的谱带类型为1~4种,种间没有出现相同的带型。种内各材料间谱带类型可完全相同,带型间的最大相似系数为0.941,而种间最大相似系数则为0.606。     

小偃系列小麦品种的HMW-GS和醇溶蛋白分析

为探讨小偃系列小麦品种的品质相关性状的遗传基础,为小麦品质改良和品种选育提供参考。采用SDS-PAGE和A-PAGE技术对14个小偃系列小麦品种的高分子量谷蛋白亚基（HMW-GS）和醇溶蛋白进行了研究。结果表明：14份小偃系列小麦品种共出现了7种亚基和5种亚基组合类型。Glu-A1位点,1亚基是主要亚基,其频率达85．7％;G1u-B1位点,7＋9亚基是主要亚基。其频率为50％;Glu-D1位点,2＋12是主要亚基,其频率高达92．9％。1,7＋9,2＋12是主要的亚基组合类型,其频率为35．7％;小偃系列小麦品种整体品质得分较高,为7．21。14个小偃系列小麦品种共检测到19条醇溶蛋白带型。平均13．6条;其遗传距离（GD）在0．23-0．59之间,当遗传距离为0．50时,14个品种可聚为4个大类,来源相同的品种,遗传相似性大。可以聚在一起。小偃系列小麦品种的高分子量谷蛋白亚基和醇溶蛋白的遗传变异较小。遗传基础较狭窄。     

航天搭载小麦种子SP3代的遗传变异分析

为探讨航天搭载对小麦籽粒的诱变效应,给航天诱变育种提供理论支持,本研究利用酸性聚丙烯酰胺电泳和SRAP技术对航天搭载小麦品种白硬冬2号SP3 代种子的醇溶蛋白和基因组DNA进行了分析,结果表明航天诱变能够诱发醇溶蛋白和基因组DNA发生变异。在15个SP3代材料中,有8个材料的醇溶蛋白组成发生了变异,醇溶蛋白四个分区对航天诱变的敏感程度不同,以ω区最为敏感,产生的变异最多。利用25对SRAP引物对15个SP3代材料的基因组DNA变异进行了分析,共扩增出227条多态性条带,15个小麦航天诱变后代材料与对照间的遗传相似系数为0.821-0.937。     

青海燕麦农家品种的醇溶蛋白电泳分析(简报)

燕麦(Avena)是粮草兼用作物,适合在高海拔地区种植,是我国"老、少、边、穷"地区的特有作物.燕麦遗传资源的收集与鉴定工作对燕麦的遗传育种有重要意义.我国的燕麦遗传资源征集工作虽然起步较晚,但成效显著,已入编和待入编<中国燕麦品种资源目录>的燕麦种质资源数共有4 400～4 500份[1].     

Splitting nitrogen applications improves wheat storage protein composition under low N supply

For the baking quality of wheat flours, the composition and concentration of grain protein are crucial. It is common practice to use late nitrogen (N) application to increase grain protein concentration (GPC) and hence, improve baking quality. However, the use of N fertilizer—particularly shortly before harvest—involves environmental risks. With the suitability of GPC as a parameter for baking quality predictions being more and more questioned, there are further investigations needed considering not only the GPC but also the composition of grain protein. Gluten protein composition varies depending on genotype and environmental factors, such as weather conditions and fertilization rate. To examine whether the effect of a split N application varies under different amounts of total N supply, this study investigates the effects of split nitrogen application on grain protein concentration and composition of wheat (Triticum aestivum L. cv. JB Asano) at four different N fertilization levels (0.8; 1.0; 1.2, and 1.4 g N pot^?1) in a pot experiment. The GPC was affected by both, N fertilization level and split N application. In this experiment, the minimum GPC of 13%, which is required for class A wheat varieties, was only achieved when N supply was moderate (at least 1.2 g N per pot). Considering the storage protein composition, the split N application influenced the proportion of α‐/β‐gliadins and γ‐gliadins, the alterations being inconsistent. The ratio of high molecular weight (HMW) to low molecular weight (LMW) glutenin subunits was increased by the split N application only at the lowest N fertilization level. It is concluded that splitting N fertilization into three doses and hence applying one dose of N late in the season can still be a useful approach to improve GPC as well as protein composition – especially when the total N supply is low.     

Salt-Induced Disaggregation/Solubilization of Gliadin and Glutenin Proteins in Water

The effect of salt concentration used in preparing gluten, on the subsequent dissolution of gluten in water, was examined. Flour from a Canadian hard red spring wheat cultivar, Katepwa, was used to prepare glutens using three different solvents, i.e. distilled deionized water (DDW), 0·2% NaCl solution and 2% NaCl solution. The isolated wet glutens were extracted sequentially with DDW, providing four water soluble fractions and an insoluble residue. The amount of protein in each fraction was determined and respective compositions were assessed electrophoretically under reducing and non-reducing conditions. Surprisingly, DDW extracts of gluten prepared with 2% NaCl contained almost all the gliadins, except some ω-gliadin components, and most of the polymeric glutenin. For the gluten prepared with 0·2% NaCl, most of the gliadin, but only a small portion of glutenin, was extracted. For gluten prepared with DDW, only part of the gliadins and almost no glutenin was extractable with water. The DDW solubilities of gluten proteins prepared in DDW, 0·2% NaCl and 2% NaCl were 27, 52, and 85%, respectively, after four sequential extracts with DDW. The large increases in the solubility of gliadin and glutenin proteins in DDW when the gluten is prepared in salt solution (after removal of most of the salt) can be explained on the basis of a salt-induced conformational change of the proteins, which renders water a more effective solvent.