抗稻瘟病新基因pi-hit-1的克隆与功能研究

采用差异显示法(DD-PCR)寻找易感稻瘟病的突变品系与野生型对照品系中的差异表达基因。结果发现与野生型对照相比,Rubisco小亚基、pi-hit．1(AF450251)和pi-hit-2(AF448491)基因在易感稻瘟病的突变品系中高表达,pi-hit-1和pi-hit-2是功能未知的新基因。进一步采用电子克隆和RT-PCR方法克隆了pi-hit-1基因的全长eDNA(AF514859),该基因编码的蛋白质属于ATP依赖的Clp蛋白酶家族。分析pi-hit-1基因的组织特异性表达发现,此基因在叶片组织特异表达。进一步设计接种诱导实验研究pi-hit-1基因表达与水稻稻瘟病易感性的关系。在易感稻瘟病的突变品系中pi-hit-1受稻瘟病菌诱导,接种后其表达量明显升高,而野生型对照品系pi-hit-1基因表达在接种前后无明显变化。比较易感稻瘟病的突变品系与对照品系pi-hit-1基因序列差异发现,稻瘟病敏感品系中pi-hit-1基因第一外显子发生缺失突变使pi-hit-1蛋白功能缺失,导致突变品系易感稻瘟病。这些实验结果提示野生型pi-hit-1是稻瘟病抗性基因。     

用农杆菌真空渗透法在烟草中瞬时表达人酸性成纤维细胞生长因子

利用农杆菌真空渗透法在烟草中瞬时表达了人酸性成纤维细胞生长因子(haFGF)基因,并对影响表达量的几个因素进行了研究.结果表明,在真空渗透后4天,外源基因获得最高水平的表达,烟草Nicotiana benthamiana(N.b)的表达量明显低于烟草N.H(转基因沉默抑制子Hc-pro的N.b植株).pM390-haFGF、pM390-haFGF/KDEL、pM390-SP/haFGF/KDEL三种表达框架被用来表达人酸性成纤维细胞生长因子,结果表明框架pM390-haFGF/KDEL的表达效果最好,受伤叶片和Valentine的培养方法要比完整叶片和Kapila的培养方法的表达量高.     

基于cDNA微阵列技术对激活蛋白处理水稻后信号传导及防卫反应相关基因的研究

为探讨激活蛋白对植物抗病防虫作用的机理,应用水稻10368条非冗余序列标签(ESTs)所制备的cDNA微阵列及荧光信号Cy3、Cy5杂交体系,对激活蛋白处理水稻后信号传导及防卫反应相关基因进行了研究,并利用半定量RT-PCR方法验证了相关基因的表达.结果表明:激活蛋白处理水稻后1～5d内,诱导了NPR1和bZIP等信号传导相关基因的上调表达,同时对APX、GST、CHS及PR1a等防卫基因的表达也有促进作用.激活蛋白诱导水稻启动了水杨酸介导的系统获得抗性(systemic acquired resistance, SAR)反应.     

激发子诱导植物基因表达研究进展

介绍了基因诱导表达调控的研究方法，并概述了与ABA，乙烯，真菌激发子诱导表达相关的顺式作用元件（G-box,GT-1结合位点，GCC－blox,W-box)，以及与这些顺式作用元件相互作用的转录因子（GBFS，GT－1，EREBPS，WRKY）。同时对植物基因诱导表达调控的分子机制作了综述。     

热诱导FLP重组酶删除转基因烟草外源基因

利用热激启动子Hsp18.2、FLP重组酶基因及其专一识别位点构建了重组酶删除系统的植物表达载体转化烟草.热激处理后转基因植株中FLP重组酶表达并识别两个同向loxP-frt重组酶识别位点,使两位点间的DNA插入片段(包含kn1、gus、nptⅡ基因)从转基因烟草基因组中删除,由kn1基因引起的转基因烟草特殊表型及gus基因产生的蓝色表型消失.     

hsa-miR-197在子宫肌瘤中的表达及生物信息学特征分析

应用实时定量聚合酶链式反应(PCR)技术检测子宫肌瘤组织中的hsa-miR-197表达水平,并与配对正常子宫肌细胞对比。通过miRbase、UCSC、NCBI等在线数据库获取并分析hsa-miR-197序列保守性及其基因组特征。选择miRanda、MirTarget2及TargetScan三个在线数据库预测hsa-miR-197的靶基因并取交集以便后续分析。通过基因本体(GO)功能注释、GO富集分析和信号转导通路富集分析初步阐明,hsamiR-197靶基因参与调控的细胞功能与信号通路。hsa-miR-197的功能较广泛,参与肿瘤发生的多种生物学过程,提示hsa-miR-197可能与子宫肌瘤的发病机制密切相关。     

抗乙肝病毒表面抗原PreS1(20-47)的单链抗体在转基因烟草根分泌物中的初步表达

为探索利用植物根分泌表达重组蛋白的可行性，构建了含有抗乙肝病毒表面抗原PreS1(20—47)单链抗体(ScFv)基因的表达载体。该ScFv基因转化烟草后在烟草根部细胞的细胞质和内质网中获得表达。实验结果表明，5’端融合ER导向信号肽的重组ScFv可通过根分泌表达。     

根据基因表达谱与基因功能模块研究大鼠抑郁症发病的分子机制

用Willner法构造大鼠抑郁症模型,由基因芯片检测8例模型和8例正常大鼠的基因表达谱,识别差异表达基因,寻找差异表达基因功能模块并构建基因表达相关网络,研究大鼠抑郁症模型的分子病理机制.在基因本体(GO)功能体系中寻找显著富集差异表达基因的疾病相关功能模块,提取疾病相关功能模块中的基因构造表达相关网络.从中选择显著多地与其它基因共表达的基因定义为HUB基因,并进一步研究其与疾病的关系.筛选得到207个差异表达基因及13个差异表达基因功能模块,主要涉及神经肽激素活性、信号传导通路、核糖体生成以及蛋白质转运与降解.在共表达相关网络中进一步识别了4个差异表达的HUB基因.利用基因功能模块和表达相关网络研究疾病机制的结果显示,抑郁症的发病可能涉及单胺递质的释放、信号传导以及神经肽激素调节等通路协同作用.     

转拟南芥AtNHX1基因促进烟草对钾吸收的研究

提取拟南芥总RNA,反转录合成Na /H 逆向转运蛋白基因AtNHX1,构建了植物高效表达载体,用叶盘法将其导入烟草,经筛选获得了抗卡那霉素和GUS染色阳性的转化子38株.应用荧光定量PCR方法对转化材料部分含AtNHX1基因的烟草内源钾通道基因、烟草K 转运蛋白基因和烟草焦磷酸酶基因的转录水平进行了分析.结果表明:在转化烟草中可以检测到AtNHX1基因mRNA,与未转化材料相比,烟草钾离子转运蛋白基因NtHAK1的转录降低,H -ATPase基因NHA1转录增加,钾通道基因NKT转录无显著变化,T1代转化烟叶中K 含量显著增加,Na 、Ca2 无显著变化,烟叶中总糖含量降低,证明了编码拟南芥AtNHX1基因与植物的K 吸收有关.     

cAMP信号通路在5-羟色胺诱导硬壳蛤卵母细胞成熟过程中的作用

采用体外药物诱导的方法,研究了5-羟色胺(5-HT)诱导的硬壳蛤(Mercenaria mercenaria) 卵母细胞成熟过程中 cAMP 信号通路的作用.结果表明,浓度为0.01～100μM的5-HT 均能够显著地诱导硬壳蛤卵母细胞的成熟,处理 60min 时生发泡破裂(GVBD)发生率均可达到 70% 左右.不同浓度 5-tHT 的诱导作用表现出时间依赖性,但未表现出浓度依赖效应.咖啡因、茶碱和 3- 异丁基-1-甲基黄嘌呤(IBMX)可以单独抑制卵母细胞的自发成熟,但效果不显著.10mM的咖啡因和茶碱以及 5mM 的 IBMX 能够显著地抑制 5-HT的诱导效果.1mM 的 IBMX 对 5-HT 的诱导效果影响不显著,1mM的咖啡因和茶碱能够促进 5-HT 的诱导作用,但差异不显著.研究结果表明,cAMP 信号通路参与了 5-HT 诱导的硬壳蛤卵母细胞的成熟过程,并且 cAMP 浓度的升高会抑制其成熟,cAMP 信号通路在硬壳蛤卵母细胞的成熟过程中可能起着负调控的作用.     

Enhanced tolerance and remediation of anthracene by transgenic tobacco plants expressing a fungal glutathione transferase gene

Plants can be used for remediation of polyaromatic hydrocarbons, which are known to be a major concern for human health. Metabolism of xenobiotic compounds in plants occurs in three phases and glutathione transferases (GST) mediate phase II of xenobiotic transformation. Plants, although have GSTs, they are not very efficient for degradation of exogenous recalcitrant xenobiotics including polyaromatic hydrocarbons. Hence, heterologous expression of efficient GSTs in plants may improve their remediation and degradation potential of xenobiotics. In the present study, we investigated the potential of transgenic tobacco plants expressing a Trichoderma virens GST for tolerance, remediation and degradation of anthracene—a recalcitrant polyaromatic hydrocarbon. Transgenic plants with fungal GST showed enhanced tolerance to anthracene compared to control plants. Remediation of ¹⁴C uniformly labeled anthracene from solutions and soil by transgenic tobacco plants was higher compared to wild-type plants. Transgenic plants (T₀ and T₁) degraded anthracene to naphthalene derivatives, while no such degradation was observed in wild-type plants. The present work has shown that in planta expression of a fungal GST in tobacco imparted enhanced tolerance as well as higher remediation potential of anthracene compared to wild-type plants.     

表达harpin基因的大肠杆菌DH5（pCPP430）诱导植物抗病性的研究

用表达ｈａｒｐｉｎ基因的大肠杆菌ＤＨ５进行了诱导植物抗病性的研究，发现表达ｈａｒｐｉｎ基因的重组菌除可明显诱发烟草、番茄叶片的过敏反应外，对玉米、水稻叶片也可诱发过敏反应，反应比相应阳性对照病菌速度快，坏死斑也更典型。用ＤＨ５菌悬液喷雾或注射诱导后，番茄对早疫病、水稻对稻瘟病、玉米对大、小斑病、马铃薯对软腐病的抗性均有不同程度的提高，与水杨酸诱导的抗性效果相当或比其略高。     

阿司匹林表面印迹微球的制备与药物缓释性能评价

采用表面印迹技术,选取γ-氨丙基三甲氧基硅烷(APTS)和甲基丙烯酰氯修饰的硅胶为载体,以阿司匹林(Asp)为模板分子,丙烯酰胺(AM)为功能单体,乙二醇二甲基丙烯酸酯(EDGMA)为交联剂,在乙腈溶液中合成了阿司匹林表面分子印迹聚合物微球(MIPs)和非印迹聚合物微球(NIPs)。通过紫外、红外光谱、扫描电镜、透射电镜、热重分析以及吸附实验进行了表征并进行了药物扩散实验。结果表明,MIPs平衡吸附量可达164.40μmol/g,对苯甲酸(BA)和水杨酸(SA)的分离因子达到3.15和3.32,有很好的热稳定性和选择性吸附能力;MIPs持续释药时间是NIPs的2.6倍,有很好的缓释效果和应用价值。     

苏云金芽孢杆菌cry1Aa核心毒素基因转化烟草及其杀虫活性

将苏云金芽孢杆菌cry1Aa的C端编码区截短,获得编码N端609个氨基酸约1.8kb的核心毒素基因,将其构建到植物表达载体转化烟草,研究直接表达的活性ICP核心毒素被昆虫取食后的杀虫效果.T1代种子发芽的抗生素抗性分离和PCR检测证实cry1Aa核心毒素基因整合到了烟草基因组,Western 杂交检测表明转化烟草能够正常表达大小为75.6kD的核心毒素蛋白.生物测定结果表明,转化烟草对初孵棉铃虫平均有高于60%的致死率,对初孵甜菜夜蛾平均达到70%的致死率,最高致死率均可达到90%以上,并对昆虫的生长发育有明显的抑制作用.     

Thermal decomposition and kinetics studies on 1,4-dinitropiperazine (DNP)

DNP, a nitramine, has been studied with regard to the kinetics and mechanism of thermal decomposition, using thermogravimetry (TG), differential thermal analysis (DTA), infrared (IR) spectroscopy, and differential scanning calorimetry (DSC). The IR spectra of DNP have also been recorded and the kinetics of thermolysis has been followed by non-isothermal TG. The activation energy of the solid-state process was determined using Flynn-Wall-Ozawa method. The actual reaction mechanism obeyed nucleation and growth model, Avramie Erofeev function (n=1) with integral form Galpha=-ln(1-alpha) (alpha=0.10-0.65). Ea and A were determined to be 116.51 kJ/mol and 10(10.52) s(-1). The T/Jump FT-IR analysis showed that CH2O, NO2, and NO are produced in larger amounts than CO2 and HCN. The cleavage of the N-N and C-N bond appears to be the primary step in the thermolysis of DNP.     

植物激素影响蓝莓果实采后衰老进程研究进展

目的概述不同植物激素及生长调节剂作用机理,探讨其在采后蓝莓果实衰老过程中的作用,展望如何延长蓝莓果实的贮藏期。方法介绍植物激素乙烯、水杨酸(SA)、茉莉酸甲酯(MeJA)、脱落酸(ABA)及植物生长调节剂1-甲基环丙烯(1-MCP)的作用,及其对采后蓝莓果实衰老进程的影响和在保鲜领域的应用。结果由于蓝莓果实成熟于高温多雨的季节,且其果实含水率高、果皮薄,导致其贮藏性差,采后极易发生软化,最终衰老腐烂。近年来的研究表明除细胞壁降解酶类之外,内源激素含量也能调控果实的成熟及衰老,而施用不同植物激素及生长调节剂则是延缓果实衰老的有效措施。结论高浓度外源乙烯及脱落酸的施用会加速果实软化及衰老现象的发生,适当浓度的乙烯、1-MCP、SA、MeJA处理可以延缓果蔬采后衰老所带来的腐败变质进程。     

Role of Soil and Foliar-Applied Carbon Dots in Plant Iron Biofortification and Cadmium Mitigation by Triggering Opposite Iron Signaling in Roots

In China, iron (Fe) availability is low in most soils but cadmium (Cd) generally exceeds regulatory soil pollution limits. Thus, biofortification of Fe along with mitigation of Cd in edible plant parts is important for human nutrition and health. Carbon dots (CDs) are considered as potential nanomaterials for agricultural applications. Here, Salvia miltiorrhiza-derived CDs are an efficient modulator of Fe, manganese (Mn), zinc (Zn), and Cd accumulation in plants. CDs irrigation (1 mg mL⁻¹, performed every week starting at the jointing stage for 12 weeks) increased Fe content by 18% but mitigated Cd accumulation by 20% in wheat grains. This finding was associated with the Fe³⁺-mobilizing properties of CDs from the soil and root cell wall, as well as endocytosis-dependent internalization in roots. The resulting excess Fe signaling mitigated Cd uptake via inhibiting TaNRAMP5 expression. Foliar spraying of CDs enhanced Fe (44%), Mn (30%), and Zn (19%) content with an unchanged Cd accumulation in wheat grains. This result is attributed to CDs-enhanced light signaling, which triggered shoot-to-root Fe deficiency response. This study not only reveals the molecular mechanism underlying CDs modulation of Fe signaling in plants but also provides useful strategies for concurrent Fe biofortification and Cd mitigation in plant-based foods.     

Stability, antimicrobial activity, and cytotoxicity of poly(amidoamine) dendrimers on titanium substrates

In this article, we present the first report on the antibacterial activity and cytotoxicity of poly(amidoamine) (PAMAM) dendrimers immobilized on three types of titanium-based substrates with and without calcium phosphate coating. We show that the amino-terminated PAMAM dendrimers modified with various percentages (0-60%) of poly(ethylene glycol) (PEG) strongly adsorbed on the titanium-based substrates. The resultant dendrimer films effectively inhibited the colonization of the Gram-negative bacteria Pseudomonas aeruginosa (strain PAO1) and, to a lesser extent, the Gram-positive bacteria Staphylococcus aureus (SA). The antibacterial activity of the films was maintained even after storage of the samples in PBS for up to 30 days. In addition, the dendrimer films had a low cytotoxicity to human bone mesenchymal stem cells (hMSCs) and did not alter the osteoblast gene expression promoted by the calcium phosphate coating.     

In Planta Response of Arabidopsis to Photothermal Impact Mediated by Gold Nanoparticles

Biological responses to photothermal effects of gold nanoparticles (GNPs) have been demonstrated and employed for various applications in diverse systems except for one important class – plants. Here, the uptake of GNPs through Arabidopsis thaliana roots and translocation to leaves are reported. Successful plasmonic nanobubble generation and acoustic signal detection in planta is demonstrated. Furthermore, Arabidopsis leaves harboring GNPs and exposed to continuous laser or noncoherent light show elevated temperatures across the leaf surface and induced expression of heat‐shock regulated genes. Overall, these results demonstrate that Arabidopsis can readily take up GNPs through the roots and translocate the particles to leaf tissues. Once within leaves, GNPs can act as photothermal agents for on‐demand remote activation of localized biological processes in plants.