控释尿素对春小麦硝酸还原酶活性和叶绿素含量的影响

[目的]研究控释尿素对春小麦不同生育期硝酸还原酶活性和叶绿素含量的影响。[方法]采用盆栽试验,以自制的3种控释尿素（CRU1、CRU2和CRU3）和普通尿素为氮源处理,测定了各处理小麦不同生育期的硝酸还原酶活性和叶绿素含量。[结果]控释尿素能提高春小麦各生育期的硝酸还原酶活性,其中CRU3对硝酸还原酶活性影响显著;控释尿素提高了植株各生育期的叶绿素含量。[结论]CRU3为小麦品种克98R-813的最佳氮源。     

棉花GhDHAR3基因克隆、功能序列分析及烟草的遗传转化

对棉花EST数据库进行同源搜索、比对和序列拼接,经RT-PCR从陆地棉纤维组织中扩增得到脱氢抗坏血酸还原酶基因GhDHAR3的cDNA,其开放阅读框为792 bp,编码由263个氨基酸组成的蛋白质.同源性比对分析显示GhDHAR3蛋白具有较高的保守性,进化树分析表明其与拟南芥AtDHAR3亲缘关系较近.利用软件进行蛋白...     

The ultrastructure of low temperature stimulated rubber-producing cortical parenchyma in guayule

The low temperatures of the Chihuahuan Desert stimulate rubber biosynthesis in guayule plants, primarily by promoting rubber-producing cortical parenchyma cells and inducing the activity of enzymes in the pathway of rubber biosynthesis. Further progress in increasing rubber production in guayule requires a better understanding of the ultrastructure of the organelles in the rubber producing cortical parenchyma. The objective of this study was to investigate the ultrastructure of the organelles in the rubber producing cortical parenchyma. The electron photomicrographs show that the rubber-producing cortical parenchyma, in contrast to mature cortical parenchyma in stems not exposed to the low temperatures, contain a high population of rubber particles, an abundant number of mitochondria, chloroplasts, a well-structured nucleus, rough endoplasmic reticulum and Golgi apparati. The double membrane nucleus is important in the low temperature induction of rubber-forming enzymes: rubber transferase and 3-hydroxy-3-methylglutaryl coenzyme A reductase. Photographic enlargements of the population of mitochondria show well-developed inner membrane folding that functions in ATP production to support the energy requirements of rubber biosynthesis. Electron photomicrographs show dividing chloroplasts that increase the number of plastids in the rubber-producing parenchyma. The well-structured grana and stroma lamellae may produce energy for the stroma production of carbon precursors of rubber. Photographic enlargements show a cortical parenchyma with an active Golgi apparatus, producing an abundant number of vesicles. Features of this electron photomicrograph is the fusion of a Golgi vesicle with a rubber particle, suggesting the transport of Golgi-processed glycolipids and glycoproteins to the rubber particles, and the rubber particles extending into the central cytosol still attached to the RER indicating an earlier origin of the rubber particle from the RER. The electron photomicrographs of the ultrastructure of rubber-producing cortical parenchyma in guayule stems support the conclusion that these cells contain an abundant number of organelles relating to the low temperature stimulated rubber synthesis.     

白花泡桐羟基肉桂酰辅酶A还原酶mRNA全序列克隆及序列分析

经过对其他物种CCR mRNA序列的对比分析后,设计保守区兼并引物,首先用RT-PCR方法得到229 bp CCR mRNA部分序列,之后通过RACE(Rapid Amplification of cDNA Ends)方法,成功克隆得到包括5'UTR和3'UTR在内的CCR全部mRNA序列,并进行了分析,所得CCRmRNA全序列共1 243个碱基,CDS共999个碱基(103-1 101),编码氨基酸332,和其他多个物种的CCR序列比对结果显示相似度均在80%以上。此序列成功克隆之前,尚未见到白花泡桐木质素代谢关键酶基因的报道,这对丰富白花泡桐基因资源、有针对性的进行白花泡桐品质或材质改良有巨大的意义。     

茶树花青素还原酶基因在大肠杆菌中的表达及优化

茶树花青素还原酶是催化非酯型儿茶素EC和EGC合成的关键酶。采用RT-PCR技术,获得了茶树花青素还原酶基因的开放阅读框,它编码含337个氨基酸的蛋白质,推测分子量为37kD,等电点为6.54;成功地将该基因重组到表达载体pET32a(+)上,并在大肠杆菌rosetta中进行原核表达;优化了原核表达中诱导时间、诱导温度、IPTG浓度、氨苄青霉素浓度,纯化出目的蛋白。HPLC检测表明,目的蛋白具有ANR酶活性。     

New isoflavonolignan with quinone reductase inducing activity from Alhagi pseudalhagi (M.B.)

Bioassay-directed separation of the chloroform extracts from the air-dried aerial part of Alhagi pseudalhagi (M.B.) led to the isolation of a new isoflavonolignan (1), together with five known isoflavones (2–6) (Fig. 1). Their structures were identified on the basis of spectral analysis of NMR, MS, IR, UV and CD spectral evidences. The quinone reductase (QR) inducing activities of the extracts and compound 1 were evaluated and the new isoflavonolignan (1) exhibited moderate quinone reductase (QR) inducing activity for hepa lclc7 cells.     

欧美杨107木质素生物合成酶CCR基因的克隆及其鉴定

木质素作为草类饲料消化性的限制因子,直接影响饲料的利用率,而CCR是木质素生物合成关键酶之一。从正在分化的2a生欧美杨107次生木质部RT-PCR扩增出的基因片段,与pMD20-T载体连接,重组质粒经限制性内切酶酶切、特异引物PCR扩增和测序鉴定。结果表明该扩增片段长为961bp,含一个编码301氨基酸的完整开放阅读框,其核苷酸序列与Leple等发表的白杨杂种Populus trichocarpa CCR的cDNA序列(AJ224986)同源性达到98.2%,并且反向插入到pMD20-T载体,因此构建了CCR的反义大肠杆菌表达载体,为后续的基因操作打下基础。该基因序列已提交国际核苷酸序列库,登录号为AM921698。     

高铁肌红蛋白还原酶活力测定方法的优化

高铁肌红蛋白还原酶是和肉色相关的一类酶,它可以阻抗引起肉品褐变的高铁肌红蛋白的生成,从而延长肉品货架期。对高铁肌红蛋白还原酶活力的测定方法进行优化,结果表明,在测定高铁肌红蛋白还原酶活力的标准反应物中,酶粗提液的添加量为0.3mL,以牛心为材料,高铁肌红蛋白的添加量为0.1mL,以牛背最长肌为材料,高铁肌红蛋白的添加量为0.05mL,NADH的添加量均为0.2mL;测定酶反应的最适温度为25℃,保温时间为25min。在酶标准反应物中,只有NADH是必须的起始物质,以前报道过的电子传递体K4Fe(CN)6并非必须反应物质,但它和底物高铁肌红蛋白和EDTA都有增强酶活力的作用。     

不同氮浓度对广金钱草苗期生理特性的影响

采用田间试验的方式,设0mg/L,150mg/L,300mg/L,450mg/L和600mg/L5个N浓度处理,研究其对广金钱草苗期叶片气体交换、叶绿素(Chl)含量、可溶性蛋白(SP)含量和硝酸还原酶(NR)活性的影响.结果表明,随着N浓度的升高,广金钱草叶片净光合速率(Pn)和蒸腾速率(Tr)升高,而胞间CO2浓度(Ci)下降,Chl a、Chl b、Chl a b、SP含量以及NR活性也表现为升高.线性回归分析结果表明,Pn、Tr与Chl a、Chl b、Chl a b、SP含量、NR活性之间存在显著的正相关关系,而Ci与Chl a、Chl b、Chl a b、SP含量、NR活性之间则存在显著的负相关关系.因此,施N可以加强广金钱草的光合作用和氮代谢,促进其生长发育.     

氮肥不同比例分期施用对玉米硝酸还原酶活性的影响

对氮肥不同比例分期施用下的玉米叶片和根系中硝酸还原酶活性(NRA)的变化进行研究。结果表明：玉米叶片中硝酸还原酶活性在整个生育期内呈单峰曲线变化,根系中硝酸还原酶活性呈双峰曲线变化。在各生育时期,NRA随氮肥施入比例的不同而发生变化。在生育后期,9.5万株/hm²密度下的玉米叶片和根系中硝酸还原酶活性低于8.5万株/hm²,NRA与产量的相关性更显著。