植物体内的黄酮类化合物代谢及其调控研究进展

针对黄酮类化合物的生物合成、贮存、转运途径、代谢调控因子、合成关键酶及其基因调控等方面的研究现状与进展进行了总结和分析.植物体内黄酮类化合物具有增强植物抗逆性和化学防御功能,在植物的生态适应过程中发挥着积极作用.其种类及含量受植物本身的遗传因素以及环境中生物和非生物因子的影响,可以通过选择或培育合适的种类、改变其遗传特性及环境条件等,调控植物体内黄酮类化合物含量.但关于调控黄酮类化合物的信号分子及其调控途径、各转录因子及蛋白质的调控机理尚未明确,调控黄酮类化合物生物合成的功能基因组或蛋白质组学等领域的研究还有待进一步深入.     

调控植物类黄酮生物合成的转录因子研究进展

植物色泽表型的差异取决于体内色素种类、含量、色素分布及表皮细胞形态等多方面的内在因素。笔者从调控类黄酮色素合成途径的转录因子入手,结合国外该研究领域中取得的成果,对调控类黄酮生物合成的转录因子的类型、表达特性、功能和进化研究进行总结和分析,探讨其在花色选育中的应用前景。     

植物八氢番茄红素合成酶基因研究进展

类胡萝卜素与植物的生长发育和光合作用密切相关,对作物品质贡献显著.八氢番茄红素合成酶(phytoene synthase, PSY)是植物体内类胡萝卜素合成通路的端口酶和限速酶,其表达丰度和活性高低直接调控植物体内类胡萝卜素的含量.植物PSY基因的功能受到其自身遗传学、类胡萝卜素合成通路基因及代谢物、各种外界非生物环境等等各种因素的调控.充分认识PSY基因的功能特性和调控机制,并对其进行合理的设计改造可能是未来提高植物体内类胡萝卜素含量的重要途径.作者对不同植物中PSY基因的功能及调控机制的相关研究进展做以综述,以期为植物体内类胡萝卜素积累的遗传调控研究提供理论依据.     

猕猴桃AsA生物合成途径及调控机制研究进展

抗坏血酸(AsA)在植物生长发育及果实品质形成方面扮演重要角色,对人体健康也具有重要作用.猕猴桃果实中富含AsA,是研究植物AsA代谢与调控的宝贵材料.目前对于AsA生物合成已经有一定的了解,植物中公认的AsA生物合成途径有4种,其中对主要合成途径L-半乳糖途径研究比较透彻,其他3条途径仍有未证实的酶反应和相关基因,AsA代谢及调控机理也有待深入研究.综合国内外AsA研究现状,主要从猕猴桃中AsA积累的差异、AsA的生物合成及其相关基因与调控酶进行阐述,以期为今后通过植物生物合成途径提高AsA含量提供理论依据,为猕猴桃种质创新与品种改良奠定基础.     

植物代谢组学技术研究进展

 代谢组学对生物体或细胞中全部小分子代谢物进行定性、定量分析, 是继基因组学、蛋白组学之后又一门新兴的组学技术。植物代谢物在种类、含量、生理功能方面极具多样性, 因此植物代谢组学在代谢组学的研究中占据重要地位。植物代谢物是植物生理状态在代谢水平的反映, 从整体上研究植物代谢物的变化及其调控将为解析植物生长发育及其与环境因子的互作奠定基础。植物代谢组学已经被广泛的应用于代谢物积累模式及其遗传基础研究、代谢相关基因的鉴定及途径解析方面, 成为现代植物生物学研究中的热点领域之一。本文综述植物代谢组学分析技术的基本组成、发展状况及植物代谢组学应用于现代植物生物学研究的现状和趋势。     

真菌绿原酸的生物合成途径解析及调控策略

绿原酸具有抗氧化、抗炎、抗菌、抗病毒等生物学功能。为提高真菌中绿原酸的生物合成量,实现真菌的提质增效,本文综合分析植物与真菌绿原酸的生物合成过程及其异同,绘制了绿原酸的生物合成途径;比较目前提高绿原酸合成量的方法,发现逆环境胁迫是积累绿原酸的关键。在培养真菌的过程中,可通过UV-B处理、增加光照强度、适当的光照时长、蓝光照射、低温胁迫、干旱胁迫等物理处理来调控其生长代谢,或者施加外源激素或转录因子刺激绿原酸生物合成途径中关键调节酶的过量表达,如苯丙氨酸解氨酶(PAL)、4-香豆酰辅酶A连接酶(4CL)、莽草酸/奎宁酸羟基肉桂酰基转移酶(HCT)及羟基化肉桂酰转移酶(C3H)等,这些酶的过表达可增加绿原酸生物合成途径的流通量,进而提高真菌中绿原酸的含量。     

植物类异戊二烯生物合成相关酶基因研究进展

类异戊二烯化合物是自然界广泛存在的一大类天然化合物,具有重要的生物学功能及经济价值．在植物体内,类异戊二烯化合物的生物合成主要有2条代谢途径：甲羟戊酸（MVA）途径和2-甲基-D-赤藓糖醇-4-磷酸（MEP）途径．综述了国内外对植物中这2条代谢途径中相关酶基因的功能、分离情况、表达特性,以及2条代谢途径之间中间产物的交换等方面的研究进展．     

松科植物萜类合成酶及其基因家族研究进展

萜类化合物是松科(Pinaceae)植物中重要的代谢物,它们与松科植物生长发育、信息传递、气候适应和化学防御等关系密切,在植物生理和生态等方面具有重要功能。松科植物萜类化合物还广泛应用在制药、生物燃料以及合成化学等工业领域,具有重要的经济价值。松科植物通过甲羟戊酸途径和甲基赤藓糖磷酸途径合成所有萜类物质合成所必需的5碳前体,并在异戊烯基转移酶家族、萜类合成酶家族作用下合成单萜、倍半萜和二萜等不同长度碳链的萜类分子骨架,并进一步在细胞色素P450酶家族的作用下发生甲基化、羟基化、过氧化、糖基化等酶促反应形成具有结构极为丰富的萜类化合物。和其他次生代谢过程类似,多种酶及其基因在萜烯化合物形成过程中起到了至关重要的作用,同时,萜类化合物结构多样性的形成也主要依赖于萜类合成酶及其基因。植物中已经发现了大量的萜类合成酶,由于大量植物基因组、转录组等组学数据的公布,不断有新的萜类合成酶被报道。笔者介绍了植物萜类化合物前体的合成途径及其关键酶基因、植物萜类合成酶的结构和类型,着重阐述松科植物萜类合成酶结构、功能以及相应基因家族鉴定和系统分类的研究进展,并针对松科植物萜类合成酶及其基因研究领域存在的研究树种偏少、松科植物萜烯类代谢可能存在的特异代谢路径重视程度不够、适用于针叶树种相关基因的功能研究平台搭建欠缺、多基因网络调控松科植物萜烯类合成机制研究未得到系统开展、产脂和抗逆相关的松科植物关键基因未得到挖掘与利用等相关问题提出了建议,以期为松科植物萜类生物合成机制解析及松科植物遗传改良提供参考。     

植物生长素生物合成的生物学功能

<正>生长素是调控植物生长发育最重要的植物激素之一。自从1880年达尔文发现生长素以来,植物生长素生物合成、极性运输及其信号转导被广泛深入研究。传统观点认为生长素生物合成主要在幼嫩的叶组织和茎尖分生组织。而最近几年的研究发现,在特定发育信号或环境信号诱导下,植物体的所有组织或器官均能快速有效地合成生长素。生长素合成对植物配子体发生、胚胎发育、器官发生和向性生长等过程中具有重要调控功能,因而成为目前植物生长素研究领域中的     

MarR家族蛋白Orf17在自溶链霉菌格尔德霉素生物合成中的调控作用

格尔德霉素是自溶链霉菌产生的具有极强抗肿瘤活性的活性物质,但格尔德霉素生物合成的具体调控机制还不清楚.为了深入解析自溶链霉菌中格尔德霉素生物合成的调控机制,对其合成途径中一个MarR家族调控蛋白Orf17的功能及其调控作用进行了研究. HPLC分析显示,敲除了orf17基因的突变株中格尔德霉素的产量相比野生型降低,表明Orf17对格尔德霉素的生物合成起到了正调控作用;RT-PCR检测表明,在orf17突变株中与格尔德霉素合成相关的基因almAI、almF、almM、almH、almRⅠ、almRⅡ和almRⅢ的表达下降,表明这些基因的表达直接或间接地受到了Orf17的调控.进一步从orf17突变株中分离纯化出3个相比野生型产量升高的化合物,经鉴定为洋橄榄叶素及其衍生物.综上所述,Orf17在格尔德霉素生物合成中起到正调控作用,而对洋橄榄叶素的生物合成可能起到负调控作用.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.