人泛素结合酶UbcH5c活性突变体的构建·纯化以及催化活性研究

[目的]构建人泛素结合酶UbcH5c的活性位点突变体S22R和F62A,同时分析这2种突变体蛋白与野生型蛋白在泛素化反应中的活性差异。[方法]通过点突变(Site-Directed Mutagenesis)的方法构建2种突变体质粒,利用0.5 mmol/L IPTG分别诱导2种突变体蛋白在大肠杆菌中进行表达;将菌体超声破碎后,依次利用阳离子交换层析法对UbcH5c突变蛋白进行分离纯化,最后利用体外泛素化酶促反应结合蛋白免疫印迹杂交的方法分析野生型UbcH5c与其活性突变体UbcH5c S22R和UbcH5c F62A在泛素化修饰上的差异。[结果]人泛素结合酶UbcH5c的2个突变体蛋白S22R、F62A的泛素化修饰程度明显弱于野生型蛋白。[结论]突变体S22R和F62A突变均不同程度的改变了人泛素结合酶UbcH5c与泛素分子之间的结合活性,即2个突变的位点中第62位苯丙氨酸残基及第22位丝氨酸残基均是UbcH5c结合泛素的关键位点,而且后者对于UbcH5c结合泛素活性的影响更大。     

天然植物色素的应用研究

天然色素因其无毒无害的特性逐渐被诸多领域所应用。为进一步推进天然色素的开发和利用,该文对天然植物色素在食品加工、医疗保健、化妆品研发以及染发剂等诸多方面的应用加以详细阐述,比较天然植物色素与合成色素的差别,并对未来的色素生产市场的展望,以期使天然色素的应用满足市场需求。     

1个新的玉米半透明皱缩胚乳突变体的遗传分析及基因定位

【目的】解析半透明皱缩玉米胚乳形成机制.【方法】以纯合玉米突变体M-E-479为供试材料,通过对M-E-479籽粒进行表型鉴定、遗传分析、主要成分测定及扫描电镜观察,构建定位群体,利用图位克隆技术对突变基因进行遗传定位.【结果和结论】M-E-479突变体胚乳中脂肪含量增加,蛋白质和淀粉含量下降,淀粉粒的大小、形状、排列空间发生改变;用F2群体将突变基因定位在10号染色体SSR标记bnlg1074与umc1506之间,两标记的遗传距离约为3.6 cM,两标记的物理距离约为2.2 Mb.可见M-E-479是一个新的玉米半透明皱缩胚乳突变体,突变性状是由隐性单基因控制.     

优质水稻黄华占雄性不育突变体的筛选及初步分析

利用EMS(甲磺酸乙酯)处理优质水稻品种黄华占种子,经过田间筛选和对M1、M2代连续的遗传分析得到317份独立的、能够稳定遗传的、由单隐性核基因控制的雄性不育突变材料.通过对花器官形态观察及花粉染色分析,初步将这些突变体材料分为6类,其中花粉发育突变体在不同的花粉发育时期出现异常.这些突变材料为深入研究水稻雄性不育分子机制及开展分子设计育种提供充足的材料.98个无粉型雄性不育突变体用于雄性不育基因TDR的测序分析,其中3个突变体在3个不同的位置上出现单碱基突变.     

普洱茶发酵阶段色泽的变化及其与品质的关系

为阐明普洱茶不同发酵阶段色泽变化及其与普洱茶品质的关系,研究了恒温恒湿与恒温非恒湿条件下,接种外源优势菌（酿酒酵母）与未接种外源优势菌的云南普洱茶在不同发酵阶段的感官品质、汤色的定量分析及茶色素含量的变化。结果表明：明度指数L及明度指数差ΔL与感官指标汤色的评分呈正相关;色品指数a、b及色差值Δa、Δb与汤色感官评分、滋味评分和品质总评分均呈正相关;不同发酵阶段样的ΔL、Δb的值逐渐减小,而Δa的值逐渐增大,这与其茶红素和茶黄素的值逐渐减小和茶褐素的值不断增大是一致的。普洱茶发酵阶段色泽的量化分析可作为普洱茶品质评价的重要指标,在自动化恒温恒湿条件下发酵普洱茶,有利于实现普洱茶清洁化加工和提高普洱茶品质的稳定性。     

辣椒种质资源的红色素含量评价

以123份辣椒种质资源为材料,采用有机溶剂法测定其红色素含量及ASTA色值,用DPS数据分析软件进行聚类分析,对辣椒种质资源的红色素含量进行评估.123份辣椒种质资源中,红色素含量介于9.12～1.62 g/kg之间,平均红色素含量为5.05 g/kg,极差为7.5.ASTA色值介于336.43～59.6之间,平均ASTA色值为186.48,极差为276.83.采用类平均聚类法将123份辣椒种质资源按其红色素含量聚为5大类,分别为极高型、高型、普通型、低型、极低型.短指型、短羊角型、羊角型、线椒型、长线椒型等不同类型的辣椒在5个红色素含量类群中均有分布,推测辣椒红色素含量高低与辣椒类型没有相关性.     

Antioxidant Activity of Pigment Extracted from Green-Wheat-Bran

The anthocyanin pigment extracted from green-wheat-bran was studied to identify its antioxidant activity.The antioxidant activities of the pigment were evaluated by anti-lipid peroxidation,total antioxidant activity （TAA）,superoxide anion radical scavenging activity （SARSA）,active oxygen scavenging activity （AOSA）,and DPPH （1,1-diphenyl-2 picrylhydrazyl free radical） radical scavenging activity.The results showed that the pigment had higher antioxidant activity and TAA,SARSA,AOSA and DPPH.scavenging activities at a certain concentration than Vc （antiscorbutic vitamin,vitamin C）,and the capacity increased with the increase of pigment concentration.Its TAA was 51.06 U mL-1,1.73 times of Vc,and SARSA 18 025.21 U mL-1,2.26% higher than Vc,and AOSA 3 776.31 U mL-1,1.24 times of Vc.As to the DPPH.scavenging activity of the pigment,there was a trend that higher concentration performed higher activity significantly improved with the company of Vc.The pigment showed significant antioxidant activities evaluated by different assays.Results will provide a better understanding on antioxidant activity of green wheat and allow the screening or breeding of green wheat varieties with higher antioxidant activity for food processing.     

Cloning and Expression of Gene Responsible for High-Tillering Dwarf Phenotype in Indica Rice Mutant gsor23

High-tillering dwarf mutant gsor23 was generated from an indica rice variety Indica9 radiatied by γ-ray. Genetic analysis showed that this phenotype was controlled by one single recessive gene, which was mapped within a physical distance of 386 kb between two insertion-deletion (InDel) markers C1-WT2 and C1-WT4 on the long arm of chromosome 1. There is a known gene D10 within this region, the mutation of which causes high-tillering in rice. Sequence analysis of the D10 allele in gsor23 revealed that the base cytosine (C) at the 404^th position in the coding region was deleted, which would cause frameshift mutation after the 134^th amino acids. The mutation site and indica background of gsor23 were different from the previously reported japonica mutants d10-1 and d10-2. Therefore, gsor23 is a novel allelic mutant of D10 which encodes the carotenoid-cleaving dioxygenase 8 (CCD8), a key enzyme involved in the biosynthesis of the new plant hormone strigolactones (SLs). After treatment with GR24, a synthetic analogue of SLs, the high-tillering phenotype of gsor23 was restored to normal. Real-time RT-PCR analysis showed that D10 expression was high in roots, but low in leaves. Compared with the wild type Indica9, the expression of the SL biosynthesis gene D10 was upregulated, while genes likely involved in the SL signal transduction pathway such as D3 and D14 were down-regulated in the gsor23 mutant.     

不同浓度纤维素酶在双红葡萄酿酒中对颜色的影响

以‘双红’山葡萄为试材,通过用纤维素酶处理,对葡萄进行色素提取。结果表明:红色素最大吸收波长为530 nm。得出0.03 mol/L浓度的纤维素酶水溶液的色素提取效果最好,在料液比为1∶10,浸提温度40℃条件色素浸出率较高。颜色指标稳定后,0.03 mg/L的纤维素酶处理组L*值为26.9,透明度最低;a*值为18.6,红色色调最大;c*值为29.1,颜色最深;H*值为-53.6,红色色调最重。酿酒过程中以0.03 mg/L的纤维素酶处理组的全过程曲线波动最小,颜色最稳定。     

提取桔皮色素的研究（Ⅰ）

研究了从桔皮中有效提取桔皮色素的方法，提取率为１３．８％，讨论了温度、ｐＨ、光，热以及溶剂对色素的影响。