高温对小麦叶绿体核糖体和叶绿体蛋白质生物合成的影响

本实验用蔗糖密度梯度离心分离小麦叶片的核糖体,用 SDS-聚丙烯酰胺凝胶电泳分离叶绿体蛋白质。对在高温和常温条件下生长的小麦分析比较表明:在34℃高温下,小麦叶片能正常地形成细胞质的80S 核糖体,而影响了叶绿体的70S 核糖体的形成,从而使由叶绿体基因组控制的蛋白质的生物合成受阻。由 SDS-凝胶电泳分析表明:高温处理的小麦,其叶绿体蛋白质的电泳条带少于常温下生长的小麦。在这些消失的多肽中,主要是叶绿体基因组的翻译产物,如二磷酸核酮糖羧化酶大亚基。由于叶绿体内这些具有光合生理功能的蛋白质的合成受阻,从而导致小麦叶片光合强度的降低。     

He-Ne激光对增强UV-B辐射小麦幼苗叶绿体的影响

对“晋麦8号”小麦幼苗分别采用5 mW·mm^-2 He-Ne激光辐照、10.08 kJ·m^-2·d^-1增强UV-B辐射及二者组合进行处理,研究各处理组小麦幼苗叶绿体膜透性、叶绿体蛋白质含量以及叶绿体偶联因子CF-1的ATP酶活性、希尔反应的活性变化。结果表明：UV-B辐射后小麦幼苗叶绿体膜透性增加,叶绿体蛋白质含量有一定的下降,而ATP酶活性、希尔反应的活性均受到抑制。经过He-Ne激光辐照可使叶绿体膜透性降低、叶绿体蛋白质含量有一定的升高,同时ATP酶活性、希尔反应的活性也受到部分激活。这些变化说明增强UV-B辐射引起小麦幼苗叶绿体损伤,而一定剂量的He-Ne激光辐照可部分修复增强UV-B对小麦幼苗光合系统的损伤。     

The Supramolecular Architecture in Chloroplast Thylakoid Membranes of Warigal Wheat

Thylakoid membranes of chloroplast from first leaf and flag leaf of wheat Warigal were examined by freeze-fracture and rotary shadowing etectron microscopy. The shape, size, density and size distribution of freeze-fracture partieles of their four faces were measured and plotted as three-dimensional histograms by a Hewlett-packard 9874 A digitizer with a HP 9845 B Computer and HP 9872 C plotter. When comparisons were made among different fracture faces and between the corresponding faces of the first leaf and the flag leaf, we found that the supramolecular architecture on the four fracture faces of the flag leaf differs from that on the corresponding faces of the chloroplast thytakoid membranes of the first leaf. The most significant difference was that the EFs particles contain the photosystem Ⅱ reaction centres associated with LHCP and the PFs particles were mostly light-harvesting complex. There was a 15% increase in EFs particle density, a 22% increase in PFs particle density and a 28% increase in EFu particle density. The large PFu particles contained the photosystem Ⅰ reaction centre and the flag lcaves contained 5% more than the first leaves. In addition, the stacking of thylakoid membranes in the flag leaf was 5% more than those in the first leaf.Thus, it provides theoretical basis for the fact that the flag leaf has higher photosynthetic rate.     

Proteomic Analysis of High Temperature Stress-Responsive Proteins in Chrysanthemum Leaves

Chrysanthemum is one of the most important ornamental flowers in the world, and temperature has a significant influence on its field production. In the present study, differentially expressed proteins were investigated in the leaves of Dendranthema grandiflorum ‘Jinba’ under high temperature stress using label-free quantitative proteomics techniques. The expressed proteins were comparatively identified and analyzed. A total of 1,463 heat-related, differentially expressed proteins were successfully identified by Liquid Chromatography-tandem Mass Spectrometry (LC-MS/MS), and 1,463 heat-related, differentially expressed proteins were successfully identified by mass spectrometry after a high temperature treatment. Among these, 701 proteins were upregulated and 762 proteins were downregulated. The in-depth bioinformatics analysis of these differentially expressed proteins revealed that these were involved in energy metabolism pathways, protein metabolism, and heat shock. In the present study, the investigators determined the changes in the levels of some proteins, and their expression at the protein and molecular levels in chrysanthemum to help reveal the mechanism of heat resistance in chrysanthemum. Furthermore, the present study elucidated some of the proteins correlated to heat resistance in chrysanthemum, and their expression changes at the protein and molecular levels to help reveal the mechanism of heat resistance in this flower species. These results provide a theoretical basis for the selection of new heat resistant varieties of chrysanthemum in the field.     

小麦黄色素合成途径中Psy 基因的克隆及分子特性小麦黄色素合成途径中Psy 基因的克隆及分子特性

对普通小麦( Ttiticum aestivum) 黄色素(YP) 合成途径中的首要限速酶———八氢番茄红素合成酶(Psy) 基因进行克隆和测序, 并和玉米Psy 基因进行序列比对。结果表明, 在高和低YP 含量小麦品种中均扩增出一条长1 192 bp 的Psy 基因片段, 该片段包含一条可编码78 个氨基酸的小麦Psy 基因的外显子, 与玉米Psy 基因第4 外显子的核苷酸序列同源率为80 . 74% , 同源区域内有47 个SNPs , 但仅11 个SNPs 导致氨基酸编码序列的改变, 二者氨基酸序列的同源率达85 . 89% , 推测Psy 基因在不同物种中的表达具有较高的保守性。BLAST 聚类分析表明, 禾谷类植物Psy 基因的分类与物种的亲缘关系存在明显的相关性,小麦Psy 基因在系统进化中比禾谷类其他植物更为高级。     

Effect of ethanol on hepatic ribosomal proteins and mRNA

Levels of RNA, mRNA and separation of ribosomal proteins from control and ethanol treated rat liver, showed no change in total RNA content, but poly(A⁺)mRNA was reduced significantly in ethanolic rats. Ribosomal proteins S2, S3a, S3b, S4, L3, L4, L4a, L10a and L15 were found substantially reduced in experimental rat livers. This study suggests decrease in poly(A⁺) mRNA coupled with loss of ribosomal proteins must be responsible for decreased protein synthesis in chronic alcoholism.     

小麦加工品质相关贮藏蛋白、基因及其遗传改良研究进展

随着小麦以及相关近缘种属基因组测序的完成,各类分子生物学技术应用于小麦品质相关蛋白基因的研究越来越多,新蛋白和新基因的发现为小麦品质遗传改良提供了更大的研究空间。本文简要概述了传统贮藏蛋白的研究现状,着重介绍了目前新发现的与小麦加工品质相关的贮藏蛋白和基因的研究进展,从遗传改良的角度上提出目前存在的问题及发展方向,以期为我国小麦品质研究提供有价值的理论参考,促进品质研究更好的应用于小麦育种的实践。     

Wheat Lysin-Motif-Containing Proteins Characterization and Gene Expression Patterns under Abiotic and Biotic Stress

Lysin motif (LysM)-containing proteins (LYPs) are important pattern recognition receptors in plants. However, the evolutionary history and characteristics of LYP genes remain largely unclear in wheat. In this study, 62 LYPs were identified at genome wide in wheat. Based on phylogenetic and domain analysis, wheat LYPs were classified into 6 subgroups (group LysMe, LysMn, LYP, LYK, LysMFbox). Syntenic analysis showed the evolution of LYP genes in wheat. RNA-seq data showed that 22 genes were not expressed at any tissue or stress stimulation period. Some LYP and LYK genes were tissue- or stage- specific. The majority of TaLYK5s, TaLYK6s, TaLYP2s and TaLysMns genes were induced under chitin, flg22 and fungal treatment. qRT-PCR analysis showed that 4 genes were upregulated during Puccinia triticina infection with a peak at 18 h post inoculation. Our findings suggested that wheat LYPs may have specific roles in response to fungal infection and provided insights into the function and characteristics of wheat LYP genes.     

叶绿体J蛋白研究进展

J蛋白是广泛存在于细胞内的一种分子伴侣。它作为Hsp70的辅伴侣分子有着广泛而复杂的生物学功能。本文概述了J蛋白的相关概念、结构、种类、分布及其作用机制,并重点讨论了其在叶绿体内的功能。最后对有关J蛋白研究中需要解决的问题做了展望。     

IAA对小麦胚芽鞘质膜蛋白磷酸化的影响

磷酸化／ 脱磷酸化机制是众多信号转导过程中的重要环节,很多信号物质被细胞受体识别后引发蛋白激酶和蛋白磷酸酶活性变化,通过磷酸化／ 脱磷酸化进一步调节多种酶活性而产生各种生理效应。在对生长素ＩＡＡ 的信号转导的研究中,发现ＩＡＡ 处理的小麦胚芽鞘质膜蛋白中蛋白激酶的活性和蛋白磷酸化程度都发生改变,并找到两种受到调节的蛋白激酶。钙离子通道抑制剂ＬａＣｌ３ 阻断了ＩＡＡ 的这种作用,表明Ｃａ２＋参与了ＩＡＡ的信号转导过程。     

The chloroplast gene encoding ribosomal protein S4 in Chlamydomonas reinhardtii spans an inverted repeat — unique sequence junction and can be mutated to suppress a streptomycin dependence mutation in ribosomal protein S12

The ribosomal protein gene rps4 was cloned and sequenced from the chloroplast genome of Chlamydomonas reinhardtii. The N-terminal 213 amino acid residues of the S4 protein are encoded in the single-copy region (SCR) of the genome, while the C-terminal 44 amino acid residues are encoded in the inverted repeat (IR). The deduced 257 amino acid sequence of C. reinhardtii S4 is considerably longer (by 51–59 residues) than S4 proteins of other photosynthetic species and Escherichia coli, due to the presence of two internal insertions and a C-terminal extension. A short conserved C-terminal motif found in all other S4 proteins examined is missing from the C. reinhardtii protein. In E. coli, mutations in the S4 protein suppress the streptomycin-dependent (sd) phenotype of mutations in the S12 protein. Because we have been unable to identify similar S4 mutations among suppressors of an sd mutation in C. reinhardtii S12 obtained using UV mutagenesis, we made site-directed mutations [Arg₆₈ (CGT) to Len (CTG and CTT)] in the wild-type rps4 gene equivalent to an E. coli Gln₅₃ to Len ribosomal ambiguity mutation (ram), which suppresses the sd phenotype and decreases translational accuracy. These mutants were tested for their ability to transform the sd S 12 mutation of C. reinhardtii to streptomycin independence. The streptomycin-independent isolates obtained by biolistic transformation all possessed the original sd mutation in rps12, but none had the expected donor Leu₆₈ mutations in rps4. Instead, six of 15 contained a Gln₇₃ (CAA) to Pro (CCA) mutation five amino acids downstream from the predicted mutant codon, irrespective of rps4 donor DNA. Two others contained six- and ten-amino acid, in-frame insertions at S4 positions 90 and 92 that appear to have been induced by the biolistic process itself. Eight streptomycin-independent isolates analyzed had wild-type rps4 genes and may possess mutations identical to previously isolated suppressors of sd that define at least two additional chloroplast loci. Cloned rps4 genes from streptomycin-independent isolates containing the Gln₇₃ to Pro mutation and the 6-amino acid insertion in r-protein S4 transform the sd strain to streptomycin independence.     

两个拟南芥未知功能蛋白的亚细胞定位研究

蛋白质的亚细胞定位对于深入了解该蛋白质所行使的生理功能具有重要意义。经生物信息学预测,两个拟南芥未知功能基因At4g16410与Atl gI8060编码蛋白含有叶绿体定位信息。我们分别克隆了这两个基因5’端长199bp与220bp的DNA片段,与绿色荧光蛋白（GFP）基因构建重组表达载体pMON530-cTP1-GFP与pMON530-cTP2-GFP,经农杆菌介导转化拟南芥。两种转基因植株经激光共聚焦显微镜观察,GFP荧光仅在叶绿体中观察到,表明所克隆的两段DNA序列编码的多肽能够将At4gl6410与Atlgl8060编码蛋白质引导进入叶绿体,确定这两个蛋白质均为叶绿体蛋白质。     

Structure and Photosynthetic Characteristics of Awns of Wheat and Barley

The surface and the cross section of awns of wheat and barley were examined by scanning electron microscopy,ultrastructure of cells were observed under a transmisson electron microscope and the photosynthetic rates were measured with an oxygen, electrode and infra-red CO2 analyser. The main results were as follows :The cross section of wheat awn appeared to be acutely trianglular whereas that of barley awn was obtusely triangular. There were rows of stomota on either side of epidermis in both wheat and barley awns. Under the stomatic band there were green tissues. The green cells in the awn were differentiated from the parenchyma cells . The mature green cells possessed papillae which were rich in chloroplasts and mitochondria. The tamella system in chloroplasts was well developed and contained many starch grains. There were three vascular bundles in each awn. The sheath cells near the green tissues contained chloroplasts. The photosynthate in the green cells might pass through the sheath cells and companion cells to sieve elements. The highest photosynthetic rate of the awn was seen at the flowering stage ,reaching about 20 μmol CO2·m-2·s-1. The light compensation point was 70—80 μE·m-2· s-1. The light saturation point was about 1500 μE·m-2·s-1. The CO2 compensation point was 50—60 ppm and the CO2 saturation point was about 900ppm . The photosynthetic rate and stomatal conductance were easily effected by CO2 concentration, light intensity and the duration of illumination . There was a positive correlation between the photosynthetic rate and the chloro-phyll content in the awns. The CO2-releasing rate in photorespiration of awn was about 4–5 μmol CO2·m-2·s-1.     

新疆冬春麦区小麦地方品种贮藏蛋白遗传多样性研究

采用SDS-聚丙烯酰胺凝胶电泳（SDS-PAGE）对236份新疆小麦地方品种的高分子量麦谷蛋白亚基（HMW-GS）的组成进行了分析。结果表明：Glu-Ⅰ位点共有19种等位基因,其中Glu-Al位点3种,Glu-Bl位点7种,Glu—D1住点9种;亚基null、7＋8、2＋12在各自的位点上出现频率最高,分别达到91．95％、85．17％、80．93％;亚基组成类型共有21种,主要为null／7＋8／2＋12,频率达70．34％;同时筛选出33份含有1、2^＊、13＋16、14＋15、5＋10、1．5＋10、174-18等优质亚基的材料,可作为优质基因源。利用酸性聚丙烯酰胺凝胶电泳（A-PAGE）对其中的65份地方品种进行醇溶蛋白多样性分析。结果表明：电泳出现64条迁移率不同的谱带,构成65种组合,其中ω区出现的谱带最多,达17条;其次是β和γ区各16条,α区出现的谱带数最少,为15条。从每条谱带在65份材料中出现的频率看,总的变异范围为1．54％～93．85％;α、β、γ和ω4个分区多样性指数（H1）分别为0．498、0．386、0．523和0．348,表明新疆麦区小麦地方品种贮藏蛋白位点存在丰富的遗传多样性。     

温度影响蛋白质结晶的研究现状

温度控制作为调控蛋白质结晶过程的手段,在结晶实验中被广泛采用。热历史效应作为蛋白质结晶实验中新的影响因素,已被越来越多的科学家所重视。控制温度可以改变蛋白质的溶解度,进一步改变溶液的过饱和度,从而影响结晶过程。我们简要总结了温度对蛋白质结晶的影响及应用温度技术控制蛋白质晶体生长的各种技术,为蛋白质结晶工作提供理论和实验依据。     

DNA-Binding Proteins and Structural Characteristics of Chloroplast Nucleoids

A comparative analysis of proteins from chloroplast nucleoids was performed in two higher-plant species (Pisum sativumL. andArabidopsis thalianaL.) and a green alga Chlamydomonas reinhardtiiDang. In the nucleoids of the higher plants and the alga, 26–27 proteins were detected with their mol wts ranging from 10 to more than 94 kD. In all the species tested, the distribution of nucleoid proteins by their mol wts was similar, especially between the predominant proteins with mol wts of 10 to 40 kD. Six DNA-binding proteins (12–18 kD) were detected in nucleoids fromCh. reinhardtiichloroplasts after in vivocovalent cross-linking between chloroplast DNA and proteins. Under an electron miscroscope, some regular structures resembling nucleosome-like particles of bacterial cells were revealed.     

Studies on the Biosynthesis of Intermediate Filament Proteins in the Rat CNS

Abstract: The biosynthesis of brain intermediate filament proteins [neurofilament proteins and glial fibrillary acidic protein (GFA)] was studied with cell-free systems containing either rat spinal cord polysomes (free polysomes or rough microsomes) and rabbit reticulocyte factors or wheat germ homogenate containing spinal cord messenger RNA. The products of translation were isoated by immunoaffinity chromatography and then analyzed by two-dimensional gel electrophoresis (2DGE) followed by fluorography. The free polysome population was found to synthesize two neurofilament proteins (MW 145K, p15.4, and MW 70K, pl 5.3) and three isomers of GFA (α, β, and γ) that differ in isoelectric point. Wheat germ homogenate containing messenger RNA extracted from free cord polysomes synthesized two proteins that comigrated with neurofilament protein standards at 145K 5.4 and 70K 5.3; these proteins were partially purified by neurofilament affinity chromatography. The wheat germ system also synthesized the α, β, and γ isomers of GFA as characterized by immunoaffinity chromatographic purification and comigration with standards in 2DGE analysis. Our data are consistent with the conclusion that synthesis of neurofilament proteins requires multiple messenger RNAs. Also, synthesis of intermediate filament proteins occurs in the free polysome population; detectable amounts of these proteins were not synthcsized by the rough microsomes.