Antioxidative Activities of Oxindole-3-acetic Acid Derivatives from Supersweet Corn Powder

The components contributing to the antioxidative activity of supersweet corn powder (SSCP), which is commonly used in corn soup and snacks in Japan, were clarified and the effects investigated. 7-(O-β-Glucosyloxy)oxindole-3-acetic acid (GOA) was found to be the component most strongly contributing to the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity of the 80% ethanol extract of SSCP, and the presence of its aglycone, 7-hydroxy-oxindole-3-acetic acid (HOA) was confirmed. GOA and HOA respectively contributed 35.1% and 10.5% to the DPPH radical-scavenging activity of the 80% ethanol extract of SSCP. Mice orally administered with HOA at doses of both 500 and 1500 mg/kg showed a significantly lower (p<0.05) level of thiobarbituric acid reactive substances (TBARS) in the plasma than the vehicle-treated control. These results suggest that GOA and HOA were at least partly involved in the antioxidative activity of SSCP in vitro and that HOA might have possessed antioxidative activity in vivo.     

小麦地方品种淀粉颗粒结合蛋白及淀粉含量差异研究

淀粉颗粒结合蛋白包含了多种淀粉生物合成的关键酶,对作物淀粉品质有重要影响。本研究利用1D-SDS-PAGE,分离了74份四川、西藏及云南毗邻地区小麦的淀粉颗粒结合蛋白,对突变材料进行了分子标记检测,对总淀粉和直链淀粉含量差异进行了比较。发现供试材料中,在分子量57～130 kDa区域共有9种不同的蛋白条带。其中,2个条带可能为新的淀粉颗粒结合蛋白;存在12份Wx-B1缺失的自然突变体和3份稀有的SGP-B1缺失突变体;筛选到直链淀粉含量超过30%的材料2份,直链淀粉含量为15%左右的材料10份。这些材料为小麦淀粉品质改良及淀粉生化合成机理研究提供了基础。     

硫营养对小麦籽粒淀粉合成及相关酶活性的影响

在田间条件下,研究了施硫对小麦籽粒淀粉合成及相关酶活性的影响.结果表明:在0～20 cm土层土壤有效硫含量为5.84 mg/kg的地块上施硫不仅提高了小麦籽粒中蔗糖的含量,而且催化蔗糖降解代谢的蔗糖合成酶(SS)活性提高,利于籽粒蔗糖的降解.施硫显著提高了灌浆期间籽粒可溶性淀粉合成酶(SSS)活性,并使腺苷二磷酸葡萄糖焦磷酸化酶(ADPGPPase)和束缚态淀粉合成酶(GBSS)活性在灌浆中、后期维持在较高水平,对直链和支链淀粉的合成都起促进作用, 使总淀粉积累增加,千粒重提高,产量增加.     

冬小麦籽粒淀粉合成相关酶活性的日变化

蔗糖向淀粉的转化是决定小麦籽粒产量的重要因素.田间条件下研究了两个小麦(Triticum aestivum L.)品种"鲁麦22"和"鲁麦14"籽粒淀粉合成相关酶:蔗糖合酶(sucrose synthase,SS)、腺苷二磷酸葡萄糖焦磷酸化酶(ADP-glucose pyrophosphorylase,ADPGPPase)、可溶性淀粉合酶(soluble starch synthase,SSS)、束缚态淀粉合酶(starch granule-bound synthase,GBSS)的活性以及籽粒ATP含量的日变化.结果表明,上述酶活性呈现明显的昼夜变化特征,酶活性一般在白天较低,而在夜间呈现较高活性,而籽粒ATP含量趋势相反.相关分析表明,白天较低的酶活性可能与气温超过其适宜温度有关.对籽粒淀粉合成相关酶活性日变化的可能因子进行了讨论.     

冬小麦籽粒淀粉合成相关酶活性的日变化

蔗糖向淀粉的转化是决定小麦籽粒产量的重要因素。田间条件下研究了两个小麦(TriticumaestivumL.)品种“鲁麦22”和“鲁麦14”籽粒淀粉合成相关酶:蔗糖合酶(sucrosesynthase,SS)、腺苷二磷酸葡萄糖焦磷酸化酶(ADP-glucosepyrophosphorylase,ADPGPPase)、可溶性淀粉合酶(solublestarchsynthase,SSS)、束缚态淀粉合酶(starchgranule-boundsynthase,GBSS)的活性以及籽粒ATP含量的日变化。结果表明,上述酶活性呈现明显的昼夜变化特征,酶活性一般在白天较低,而在夜间呈现较高活性,而籽粒ATP含量趋势相反。相关分析表明,白天较低的酶活性可能与气温超过其适宜温度有关。对籽粒淀粉合成相关酶活性日变化的可能因子进行了讨论。     

渗透胁迫下小麦根系渗透调节与根冠淀粉水解的研究

用不同浓度的PEG—600对抗旱性不同的小麦幼苗进行渗透胁迫处理,研究了小麦幼苗根系的淀粉酶活性、可溶性糖含量、渗透势、渗透调节能力和根冠淀粉的水解状况。结果表明,随着渗透胁迫程度的加重,抗旱性强的小麦品种昌乐5号和北农2号根系渗透势和饱和渗透势的降低程度大于抗旱性弱的小麦品种鲁麦5号和921842,并且抗旱性强的小麦品种根系的渗透调节能力大于抗旱性弱的小麦品种。随着渗透胁迫程度的加重．各品种小麦根冠淀粉粒均有不同程度的减少。而抗旱性强的品种根冠淀粉粒的减少程度小于抗旱性弱的品种;抗旱性强的小麦品种根系淀粉酶活性显著高于抗旱性弱的小麦品种,但是,随着渗透胁迫程度的加重,抗旱性弱的品种淀粉酶活性增加的幅度远高于抗旱性强的品种。可溶性糖含量的变化趋势与淀粉酶活性的变化趋势一致．即渗透胁迫下根冠淀粉水解程度大的小麦品种,可溶性糖的含量高。但根冠淀粉水解在根系的渗透调节以及在小麦适应水分胁迫中的作用还有待于进一步探讨。     

小麦蛋白质和淀粉含量与籽粒发育过程中内源激素含量的关系

研究粒重差异较小、蛋白质和淀粉含量差异大的小麦品种‘川麦107’和‘川麦36’籽粒发育过程中激素含量变化与籽粒蛋白质和淀粉积累之间关系的结果表明,‘川麦36’蛋白质含量一直高于‘川麦107’的,而其淀粉含量一直低于‘川麦107’;‘川麦36’籽粒中ZR初始含量和IAA峰值高些,开花后5~20d籽粒中ZR含量与蛋白质含量呈显著正相关,IAA峰值与此期的蛋白质积累速率跃变相对应。两品种籽粒中GA峰值与蛋白质含量的低谷相对应,开花后5~30d的籽粒中GA含量与淀粉含量呈极显著正相关,而‘川麦107’籽粒中GA含量较高。     

花后土壤水分状况对小麦籽粒淀粉和蛋白质积累关键调控酶活性的影响

在温室盆栽条件下,以2个不同蛋白质含量的冬小麦(Triticum aestivum L．)品种皖麦38和扬麦9为材料,研究了花后第4天开始的土壤干旱(SRWC=45％～50％)和渍水对籽粒蛋白质和淀粉积累关键调控酶活性的影响。小麦叶片和籽粒的测定结果均表明,小麦源库器官中籽粒蛋白质和淀粉积累的关键调控酶活性变化趋势在2个品种间基本一致。与对照(SRWC=75％～80％)相比,干旱和渍水均明显降低了花后旗叶中蔗糖含量和磷酸蔗糖合成酶(SPS)活性,而氨基酸含量和谷氨酰胺合成酶(GS)活性略有下降。干旱和渍水均降低了籽粒库蔗糖合成酶(SS)和结合态淀粉合成酶(GBSS)活性,可溶性淀粉合成酶(SSS)活性降低尤甚。其中干旱处理下SS的下降比渍水更为明显。与对照相比,渍水明显降低了籽粒谷丙转氨酶(GPT)和GS活性,而干旱的影响较小。相关性分析结果表明籽粒淀粉产量和含量与SPS,SSS和GBSS活性的关系比与SS活性的关系更为密切,籽粒蛋白质产量和含量与叶中GS和籽粒中GPT活性的关系比与籽粒中GS关系活性更为密切。这些结果表明小麦源库器官中调控籽粒蛋白质和淀粉积累的关键酶活性变化是花后不同水分状况影响籽粒淀粉和蛋白质特性的重要因素。     

玉米淀粉分支酶基因的克隆与RNAi表达载体的构建

利用网络数据库http://jura.wi.mit.edu/bioc/siRNAext/,确定玉米淀粉分支酶SBEⅡb的部分基因序列作为RNAi的目标序列,通过RT-PCR方法从玉米自交系‘综31’中分别成功克隆出了玉米淀粉分支酶sbeⅡb基因的部分序列及其启动子序列,从大肠杆菌中成功克隆了木糖异构酶基因xylA作为筛选标记,构建了含有35S驱动的木糖异构酶基因和sbeⅡb启动子驱动的含有sbeⅡb目标序列的反向重复序列的表达载体pBAC413,并对玉米自交系实施转化。经PCR检测转基因玉米再生植株,初步判定目的序列已经成功整合到玉米再生植株的基因组中。     

糯玉米胚乳淀粉粒粒度分布形成的酶学机理

以7个糯玉米品种为材料,测定其籽粒发育过程中淀粉粒粒度分布及淀粉合成相关酶活性的变化,分析两者之间的关系。结果表明,随着籽粒发育,糯玉米淀粉粒平均粒径逐渐增大,可溶性淀粉合成酶(SSS)和淀粉分支酶(SBE)活性呈单峰曲线变化。籽粒发育前期,小淀粉粒(≤7.4μm)所占体积较大;随着籽粒发育,小淀粉粒所占体积减少,大淀粉粒(>7.4μm)所占体积增多;籽粒发育后期,大淀粉粒所占体积较大。相关分析表明, SSS和SBE活性与大淀粉粒体积增大速率和平均粒径增大速率均呈显著或极显著正相关。因此, SSS和SBE是影响糯玉米胚乳淀粉粒粒度分布形成的主要酶, SSS和SBE活性越高,淀粉粒平均粒径越大,大淀粉粒所占体积越多。     

茶叶多糖的糖醛酸含量测定及抗氧化活性研究

采用高效液相色谱法对三个产地茶叶多糖的糖醛酸含量进行了测定,该方法具有操作简便、样品无需预处理等特点,稳定性、重现性较好,回收率高,适合于茶叶多糖糖醛酸含量的测定。结果表明不同产地茶叶多糖的糖醛酸含量有明显差异。本文同时研究了不同产地茶叶多糖对超氧自由基和DPPH自由基的清除作用,以评价其抗氧化活性。结果发现不同产地茶叶多糖的抗氧化活性与其糖醛酸含量呈正相关,糖醛酸含量越高,其抗氧化能力越强。     

Selective Staining of Protein and Starch in Wheat Flour and its Products

The main constituents of wheat flour and many wheat flour products are wheat protein (gluten) and starch granules. The specific staining of the protein present was effected by 10 min in 0.1% aqueous ponceau 2R (C.I. No. 16150) acidified with 3—4 drops of 1 N H₂SO₄ per 50 ml of staining solution, followed by rinsing in 2 changes of distilled water, dehydrating, clearing and mounting in a resinous medium in the normal way. Staining of starch was as follows: sections or flour smears were brought to water, treated for 10 min in a protein-blocking reagent (Taninol ADR—Imperial Chemical Industries—used in 1% aqueous solution) rinsed, then stained for 3 mins in 0.5% aqueous chlorazol violet R (C.I. No. 32445) or for 10 min in either 0.5% aqueous chlorazol violet N (C.I. No. 22570), or chlorazol black E (C.I. No. 30235). Staining was followed by thorough rinsing, normal dehydration and clearing and mounting in a medium of R.I. about 1.49 to enhance visibility of unstained starch grains. The methods are applicable to flour smears, cryostat and wax sections.     

不同年代小麦品种旗叶的光合特性及抗氧化酶活性研究

以不同时期在黄淮冬麦区推广并具有一定代表性的5个小麦品种碧蚂1号、丰产3号、小偃6号、小偃54和小偃81为材料,研究了品种更替过程中小麦旗叶的光合特性以及抗氧化酶活性的变化.结果表明,各小麦品种旗叶净光合速率均于开花后10 d左右达到最大值后下降,并在开花灌浆期有显著差异,且近期品种始终高于早期品种.随着灌浆进程推进,各小麦品种旗叶叶绿素含量、可溶性蛋白质含量、抗氧化酶活性呈现出与净光合速率基本一致的变化趋势(其中过氧化氢酶活性为下降趋势),而丙二醛含量持续升高,但近期小麦品种始终低于早期品种且差异达到极显著水平(P<0.01).研究发现,近期育成小麦品种的旗叶在生育后期具有相对较高的光合速率,可能与其叶绿素和可溶性蛋白含量下降速率较缓、抗氧化酶活性较高、膜脂过氧化程度较轻有关.     

The Role of Starch in the Gravitropic Response of the Lentil Root

It is well accepted that the amyloplasts of the cap are responsible for gravisensing in primary roots. However, roots with starch-depleted plastids are able to respond to gravistimulus, but their curvature is slower than that of roots containing amyloplasts. The goal of our experiment was to analyse the effects of natural variations of statolith starch in the gravitropic response of lentil roots to a stimulation in the horizontal position. In lentil seedlings grown in the vertical position for 26 h, the volume of the amyloplasts in the statocytes differed between individual roots. The amount of starch in the cap was determined parallel to the rate of gravitropic curvature. There was no statistical correlation between the intensity of the gravitropic response and the starch content in the statocytes. Lentil roots were treated with gibberellic acid (GA₃) at 32°C in order to reduce the volume of starch in the statoliths. There was 53% less starch in the cap of GA₃treated roots as compared to the cap of control roots. But there was no relationship between starch content in the cap and the responsiveness of the root to a gravistimulus, except when the amount of starch was small.     

食用豆类种质资源粗蛋白及粗淀粉含量的评价

对"十五"期间收集、整理并存入国家种质库的1696份食用豆类种质资源的主要品质性状进行了鉴定评价.结果表明,9种食用豆类种质资源的粗蛋白、粗淀粉平均含量分别为24.93%、45.11%,不同食用豆类种质资源中各品质性状变异程度不同,其中菜豆和鹰嘴豆的粗蛋白和豇豆的粗淀粉含量变异最大.不同来源的食用豆类种质资源品质性状比较结果表明,国内绿豆种质资源粗蛋白含量明显优于国外种质资源.通过鉴定筛选出一批品质性状优良的食用豆类种质,并对使用的评价标准进行了讨论.     

施氮量和花后土壤含水量对强筋小麦籽粒淀粉合成及品质的影响

以强筋小麦品种'济麦20'为材料,在防雨池栽培条件下研究了施氮量和花后土壤含水量对强筋小麦籽粒淀粉合成及其品质的影响,以明确强筋小麦获得高产优质的花后适宜土壤含水量及施氮量.结果表明:在同一施氮量下,适宜的花后土壤含水量(60%～70%)籽粒游离态淀粉合成酶(SSS)和束缚态淀粉合成酶(GBSS)活性在籽粒发育过程中一直最高,有利于直链淀粉、支链淀粉的积累和支链淀粉/直链淀粉比的提高,提高峰值粘度、低谷粘度、最终粘度和衰减值;花后土壤含水量过高(80%～90%)或过低(40%～50%)均导致籽粒SSS和GBSS活性降低,从而使直链淀粉、支链淀粉的积累量降低,减小支链淀粉/直链淀粉比,使峰值粘度、低谷粘度、最终粘度降低.(2)在同一土壤含水量下,增施氮肥不利于灌浆前期SSS和GBSS活性和直链淀粉、支链淀粉积累量的提高,并且随着土壤含水量增加增施氮肥该趋势加重;适量增施氮肥能提高支链淀粉/直链淀粉比和峰值粘度、低谷粘度、最终粘度,过多或过少施氮则降低支/直比和峰值粘度、低谷粘度、最终粘度.研究认为,在本试验条件下,适量增施氮肥(纯氮225 kg/hm2)或适宜的花后土壤含水量(60%～70%)可促进强筋小麦籽粒淀粉的合成,有效改善其淀粉品质.     

Protein Kinase Activity of in vitro Cultured Plant Cells in Relation to Growth and Starch Metabolism

Taking tetcyclacis, a norbornenodiazentine derivative, as an example, the influence of a growth retardant on the shoot growth of sunflower, soybean, and maize seedlings grown and treated in hydroculture was investigated. In detail, the reduction in the length of various shoot sections {epicotyl, 1st internode, leaf blade) caused by the retardant was studied. At low concentrations of the retardant (\lt10^-6 M) the shortening effects are substantially attributable to an influence on cell elongation, whereas cell division is inhibited as the concentration increases (τ10^-6 M). A comparison of the effects of tetcyclacis in cell suspension cultures of appropriate plant species showed that also in this system concentrations τ 10^-6 M inhibited cell division growth, i. e. there is comparability of plant/ cell culture regarding the retardant effect on cell division. In contrast to the intact plants, however, cell elongation appears to be of only subordinate importance for the growth of cell cultures, as it has been shown using parsley cell suspension cultures.It is discussed to what extent influencing the gibberellin or sterol biosynthesis by means of tetcyclacis provides an explanation for the concentration-dependent effect on the cell division and cell elongation processes.     

Evaluation of alternatives to expanded polystyrene beads for mosquito control

Expanded polystyrene (EPS) beads have been shown to be an effective tool for controlling immature stages of mosquitoes, as well as preventing oviposition by adults. Polystyrene does not biodegrade quickly, resulting in some concerns about its effect on the environment. A potential solution is the use of biodegradable materials that cover the surface of mosquito breeding sites in the same way as EPS beads. Two candidates are polylactic acid (PLA) beads and corn starch shreds. Larval mortality and adult emergence of Culex quinquefasciatus Say (Diptera: Culicidae) were monitored in bowls with each of four treatments: EPS beads, PLA beads, corn starch shreds and a control. The PLA beads were as effective as EPS beads at preventing mosquito emergence, whereas the shredded corn starch treatment resulted in significantly higher rates of emergence to the control. Similarly, EPS and PLA beads resulted in 100% mortality after 10 days, while there was low mortality of larvae in the corn starch (9%) and control treatments (20%). PLA beads provided similar levels of mortality and reduction in adult emergence as EPS beads. However, the production requirements of PLA beads may limit its use in field conditions.     

Degradation of Glucan Primers in the Absence of Starch Synthase 4 Disrupts Starch Granule Initiation in Arabidopsis

Arabidopsis leaf chloroplasts typically contain five to seven semicrystalline starch granules. It is not understood how the synthesis of each granule is initiated or how starch granule number is determined within each chloroplast. An Arabidopsis mutant lacking the glucosyl-transferase, STARCH SYNTHASE 4 (SS4) is impaired in its ability to initiate starch granules; its chloroplasts rarely contain more than one large granule, and the plants have a pale appearance and reduced growth. Here we report that the chloroplastic α-amylase AMY3, a starch-degrading enzyme, interferes with granule initiation in the ss4 mutant background. The amy3 single mutant is similar in phenotype to the wild type under normal growth conditions, with comparable numbers of starch granules per chloroplast. Interestingly, the ss4 mutant displays a pleiotropic reduction in the activity of AMY3. Remarkably, complete abolition of AMY3 (in the amy3 ss4 double mutant) increases the number of starch granules produced in each chloroplast, suppresses the pale phenotype of ss4, and nearly restores normal growth. The amy3 mutation also restores starch synthesis in the ss3 ss4 double mutant, which lacks STARCH SYNTHASE 3 (SS3) in addition to SS4. The ss3 ss4 line is unable to initiate any starch granules and is thus starchless. We suggest that SS4 plays a key role in granule initiation, allowing it to proceed in a way that avoids premature degradation of primers by starch hydrolases, such as AMY3.