盐地碱蓬过氧化氢酶基因的克隆及盐胁迫下的表达分析

过氧化氢酶是清除H2O2的重要酶类.从400 mmol/L NaCl处理的盐地碱蓬(Suaeda salsa(L.)Pall)地上部分的cDNA文库中克隆了两个编码过氧化氢酶的cDNA(Sscat1和Sscat2),其中Sscat1(1.7kb)是一个全长cDNA克隆,编码一个492个氨基酸的开放阅读框架,而Sscat2(1.1kb)是一个cDNA片段.据编码Sscat1 3＇端的287个氨基酸的cDNA序列与Sscat2的cDNA序列进行的BLAST同源性分析表明,Sscat1和Sscat2在核苷酸水平的一致性为71.9%,在氨基酸水平上的一致性为75%.Southem杂交表明,Sscat1在盐地碱蓬基因组中为多拷贝基因,Sscat2则为一个单拷贝基因.Northern杂交结果表明在盐胁迫条件下Sscat1和Sscat2的表达存在差异:400 mmol/L NaCl处理48h的盐地碱蓬根中的Sscat1和Sscat2 mRNA水平比对照显著提高,但是在叶中仅Sscatl受盐诱导表达.不同盐处理时间下的表达分析也证实,在盐地碱蓬叶中仅Sscat1受盐诱导表达.这说明Sscat1和Sscat2在盐地碱蓬中是差异调控的.生理分析表明过氧化氢酶的活性在盐胁迫条件下显著提高.     

盐地碱蓬(Suaeda salsa)APX 基因的克隆及盐胁迫下的表达

从盐地碱蓬 (Suaedasalsa)中克隆了抗坏血酸过氧化物酶 (ascorbateperoxidase ,APX)的全长cDNA(SsAPX) ,基因注册号为AY0 34 893。SsAPX全长 1.1kb ,推导的氨基酸序列长为 2 5 0个氨基酸残基。BLAST同源性分析表明 ,该cDNA与已报告的菠菜(Spinaciaoleracea)细胞质抗坏血酸过氧化物酶基因同源性最高 ,在核苷酸水平上一致性为 87% ,在氨基酸水平上一致性为 89%。Southern杂交表明APX基因在盐地碱蓬基因组中只有 1个拷贝。盐 (NaCl 40 0mmol/L)处理不同时间后的Northern杂交分析表明盐地碱蓬中SsAPX基因在盐胁迫下表达量增加 ,而且在盐胁迫下抗坏血酸过氧化物酶的活性也显著地增加 ,说明该基因受盐诱导。推测抗坏血酸过氧化物酶可能在保护盐地碱蓬免受氧化损伤的过程中起到一定作用     

盐地碱蓬GST基因的克隆、序列分析及其表达特征

从盐地碱蓬 (Suaedasalsa)幼苗的cDNA文库中克隆到一个 0 .9kb的全长cDNA ,同源性分析表明该全长cDNA与已报告的大豆 (Glycinemax)GST基因相应序列的同源性达 5 5 % ,可能编码由 2 35个氨基酸组成的谷胱甘肽转移酶 (glutathioneS transferase ,GST)。Southern杂交结果证明GST基因在碱蓬基因组中可能有至少两个以上的拷贝 ;Northern杂交结果表明 ,4 0 0mmol/L的NaCl处理 4 8h ,幼叶中GSTmRNA的表达量是对照的 2～ 3倍 ,说明碱蓬中GST基因受盐诱导     

硫腺苷甲硫氨酸合成酶基因的克隆及其在盐胁迫条件下的不同表达

硫腺苷甲硫氨酸作为甲基供体在转甲基反应中起到重要作用.为了解硫腺苷甲硫氨酸在盐地碱蓬(Suaedasalsa (L.)Pall)耐盐中的作用,我们对可能编码硫腺苷甲硫氨酸合成酶的基因(SsSAMS2)进行了分析.该基因在经400 mmol/L NaCl处理的盐地碱蓬地上部分的λ-Zap cDNA文库中克隆到,其插入片段全长1 531 bp,包含一个395个氨基酸的开放阅读框架,该基因推断的分子量约为43 kD.SsSAMS2与长春花(Catharanthus roseus)的SAMS2在氨基酸水平上的一致性为93%.Southern杂交显示,SsSAMS2在盐地碱蓬基因组中可能是两个拷贝.Northern分析显示硫腺苷甲硫氨酸合成酶基因受NaCl等胁迫的正调控.酶活性检测表明,NaCl胁迫条件下该酶活性增强.     

盐地碱蓬叶片液泡膜H+-ATPase B亚基的克隆及盐胁迫下表达分析

植物液泡膜H -ATPase在建立跨液泡膜质子梯度、促进液泡Na 区域化、提高植物耐盐性方面发挥着重要作用.本实验从盐生植物盐地碱蓬(Suaeda salsa L.)cDNA文库分离到碱蓬叶片液泡膜H -ATPase B亚基cDNA克隆.测序表明该基因长达1 974 bp,开放阅读框有1 470 bp编码489个氨基酸,含有一个保守的ATP结合位点,其蛋白分子量约为54.29 kD.Northem及Western印迹表明盐地碱蓬液泡膜H -ATPase B亚基表达明显受NaCl胁迫诱导,并且在NaCl胁迫下,B亚基在转录及翻译水平上与液泡膜H -ATPase c亚基存在协同作用.盐胁迫下,盐地碱蓬液泡H -ATPase B亚基与c亚基的协同表达增加了液泡H -ATPase的数量,从而提高了液泡H -ATPase活性,为碱蓬叶片液泡Na 区域化提供了动力,最终提高了碱蓬植株的耐盐性.     

盐胁迫下盐地碱蓬叶片液泡膜H+-ATPase H 亚基的克隆与表达分析

利用EST随机挑取克隆测序的方法从盐地碱蓬叶片cDNA文库中分离得到了盐地碱蓬V-H -ATPase H亚基cDNA序列,并进行了H、c亚基基因表达及V-H -ATPase活性分析.结果表明,H亚基基因全长1 969 bp,包括100 bp的5′-非编码区和471 bp的3′-非编码区.开放阅读框为1 398 bp,编码465个氨基酸残基,分子量约52.8 kD.N orthern杂交分析表明盐胁迫明显诱导了H亚基表达,而且盐胁迫下H、c亚基及V-H -ATPase活性存在协同作用.这些结果表明盐胁迫下H和c亚基基因上调及V-H -ATPase活性的增加为N a 区隔化到液泡中提供了质子驱动力.     

硫腺苷甲硫氨酸合成酶基因的克隆及其在盐胁迫条件下的不同表达

硫腺苷甲硫氨酸作为甲基供体在转甲基反应中起到重要作用。为了解硫腺苷甲硫氨酸在盐地碱蓬(Suaeda salsa (L.) Pall)耐盐中的作用,我们对可能编码硫腺苷甲硫氨酸合成酶的基因(SsSAMS2)进行了分析.该基因在经400mmol/L NaCl处理的盐地碱蓬地上部分的λ-Zap cDNA文库中克隆到,其播入片段全长1531bp,包含一个395个氨基酸的开放阅读框架,该基因推断的分子量约为43kD.SsSAMS2与长春花(Catharanthus roseus)的SAMS2在氨基酸水平上的一致性为93%.Southern杂交显示,SsSAMS2在盐地碱蓬基因组中可能是两个拷贝.Northern分析显示硫腺苷甲硫氨酸合成酶基因受NaCl等胁迫的正调控.酶活性检测表明,NaCl胁迫条件下该酶活性增强.     

盐地碱蓬叶片液泡膜H^＋—ATPase B亚基的克隆及盐胁迫下表达分析

植物液泡膜H^ -ATPase在建立跨液泡膜质子梯度、促进液泡Na^ 区域化、提高植物耐盐性方面发挥着重要作用。本实验从盐生植物盐地碱蓬(Suaeda salsa L.)cDNA文库分离到碱蓬叶片液泡膜H^ -ATPase B亚基cDNA克隆。测序表明该基因长达1974bp,开放阅读框有1470bp编码489个氨基酸,含有一个保守的ATP结合位点,其蛋白分子量约为54．29kD。Northern及Western印迹表明盐地碱蓬液泡膜H^ -ATPase B亚基表达明显受NaCl胁迫诱导,并且在NaCl胁迫下,B亚基在转录及翻译水平上与液泡膜H^ -ATPase c亚基存在协同作用。盐胁迫下,盐地碱蓬液泡H^ -ATPase B亚基与c亚基的协同表达增加了液泡H^ -ATPase的数量,从而提高了液泡H^ -ATPase活性,为碱蓬叶片液泡Na^ 区域化提供了动力,最终提高了碱蓬植株的耐盐性。     

盐地碱蓬(Suaeda salsa)中SsINPS基因的分子克隆及表达特性分析

肌醇 1 磷酸 (I 1 P)合成酶 (EC5 .5 .1 .4,INPS)是肌醇生物合成中的关键酶 ,催化葡萄糖 6 磷酸 (G 6 P)到I 1 P的反应。从该实验室已构建的NaCl40 0mmol/L处理的盐地碱蓬 (Suaedasal sa)cDNA文库中克隆了肌醇 1 磷酸合成酶的全长cDNA (S .salsamyo inositol 1 phosphatesynthase,SsINPS) ,基因注册号为AF43 3 879。SsINPS全长约 1 986bp ,含有开放式阅读框架 1 5 3 0bp ,3′和 5′的非翻译区分别为 1 3 9bp和 3 1 7bp ;推导的氨基酸序列全长 5 1 0个氨基酸残基 ,分子量约为 5 6 .7kD ,pI值为 5 .3 5。BLAST同源性分析表明 ,该cDNA与已报告的冰叶日中花 (Mesembryanthemumcrys tallinum)的INPS基因同源性最高 ,其中 ,核苷酸水平的同源性为 91 % ,氨基酸水平上的同源性为84%。以SsINPS全长cDNA为探针进行的South ern杂交结果表明 ,SsINPS基因在盐地碱蓬基因组中只有一个拷贝 ;Northern结果表明 ,在盐处理(40 0mmol/L的NaCl)下 ,SsINPS在叶中的表达量有显著的增加。从而说明SsINPS在盐胁迫下是上升调节的     

盐地碱蓬延伸因子(SsEF-1α)的克隆与表达分析

从盐胁迫下的盐地碱蓬(Suaeda salsa)的cDNA文库中获得了一个延伸因子(SsEF-1α)的cDNA片段。以此片段为探针,对其在不同胁迫处理下的盐地碱蓬中表达利用Northern杂交进行分析,结果表明,不同盐浓度处理、同一盐浓度不同时间处理下及双氧水刺激条件下延伸因子在碱蓬叶中的表达量先呈现减少然后增加的趋势;聚乙二醇(PEG)及低温诱导下均呈现上升趋势。由此可见该基因在盐、氧化、高渗和低温胁迫条件下产生一定的反应。     

Role for dopamine in malonate-induced damage in vivo in striatum and in vitro in mesencephalic cultures

Defects in mitochondrial energy metabolism have been implicated in the pathology of several neurodegenerative disorders. In addition, the reactive metabolites generated from the metabolism and oxidation of the neurotransmitter dopamine (DA) are thought to contribute to the damage to neurons of the basal ganglia. We have previously demonstrated that infusions of the metabolic inhibitor malonate into the striata of mice or rats produce degeneration of DA nerve terminals. In the present studies, we demonstrate that an intrastriatal infusion of malonate induces a substantial increase in DA efflux in awake, behaving mice as measured by in vivo microdialysis. Furthermore, pretreatment of mice with tetrabenazine (TBZ) or the TBZ analogue Ro 4-1284 (Ro-4), compounds that reversibly inhibit the vesicular storage of DA, attenuates the malonate-induced DA efflux as well as the damage to DA nerve terminals. Consistent with these findings, the damage to both DA and GABA neurons in mesencephalic cultures by malonate exposure was attenuated by pretreatment with TBZ or Ro-4. Treatment with these compounds did not affect the formation of free radicals or the inhibition of oxidative phosphorylation resulting from malonate exposure alone. Our data suggest that DA plays an important role in the neurotoxicity produced by malonate. These findings provide direct evidence that inhibition of succinate dehydrogenase causes an increase in extracellular DA levels and indicate that bioenergetic defects may contribute to the pathogenesis of chronic neurodegenerative diseases through a mechanism involving DA.     

2018年中国植物科学若干领域重要研究进展

2018年中国植物科学继续呈现快速发展的态势, 我国科学家在国际植物科学主流学术刊物发表论文数量大幅增加, 取得了多项具有重要影响的成果。调控植物生长-代谢平衡实现可持续农业发展入选2018年度中国科学十大进展; 中国被子植物区系进化历史研究入选2018年度中国生命科学十大进展。以水稻为代表的农作物和果蔬等经济作物研究在国际上已呈现出明显的优势, 若干领域已从“追赶”状态跨越到“领跑”地位。该文对2018年中国科学家在植物科学若干领域取得的重要研究成果进行了概括性评述, 旨在全面追踪和报道当前中国植物科学领域的发展前沿和热点, 展示中国科学家所取得的杰出成就。     

2017年中国植物科学若干领域重要研究进展

2017年中国植物科学继续保持高速发展态势, 重大成果频出, 具体表现在中国植物学家在国际顶级学术期刊发表的文章数量平稳上升。中国植物科学领域的研究工作者成果精彩纷呈, 如新型广谱抗病机制的发现、水稻广谱抗病遗传基础及机制和疫霉菌诱发病害成灾机制研究等。2017年中国生命科学领域十大进展评选中, 有两项植物科学领域的研究成果入选。水稻生物学、进化与基因组学和激素生物学等领域学科发展突出。另外, 值得一提的是, 长期从事高等植物与代谢途径调控分子网络研究和水稻品种设计育种的李家洋院士的研究成果“水稻高产优质性状形成的分子机理及品种设计”荣获2017年国家自然科学一等奖。这一具有重大国际影响的开创性贡献标志着中国植物科学在该领域的国际科学前沿居于引领和卓越地位。该文对2017年中国本土科学家在植物科学若干领域取得的重要研究成果进行了系统梳理, 旨在全面追踪和报道当前中国植物科学领域发展的最新前沿动态, 与广大读者共同分享我国科学家所取得的辉煌成就。     

SSTR5 ablation in islet results in alterations in glucose homeostasis in mice

Somatostatin (SST) peptide is a potent inhibitor of insulin secretion and its effect is mediated via somatostatin receptor 5 (SSTR5) in the endocrine pancreas. To investigate the consequences of gene ablation of SSTR5 in the mouse pancreas, we have generated a mouse model in which the SSTR5 gene was specifically knocked down in the pancreatic beta cells (betaSSTR5Kd) using the Cre-lox system. Immunohistochemistry analysis showed that SSTR5 gene expression was absent in beta cells at three months of age. At the time of gene ablation, betaSSTR5Kd mice demonstrated glucose intolerance with lack of insulin response and significantly reduced serum insulin levels. Insulin tolerance test demonstrated a significant increase of insulin clearance in vivo at the same age. In vitro studies demonstrated an absence of response to SST-28 stimulation in the betaSSTR5Kd mouse islet, which was associated with a significantly reduced SST expression level in betaSSTR5Kd mice pancreata. In addition, betaSSTR5Kd mice had significantly reduced serum glucose levels and increased serum insulin levels at 12 months of age. Glucose tolerance test at an older age also indicated a persistently higher insulin level in betaSSTR5Kd mice. Further studies of betaSSTR5Kd mice had revealed elevated serum C-peptide levels at both 3 and 12 months of age, suggesting that these mice are capable of producing and releasing insulin to the periphery. These results support the hypothesis that SSTR5 plays a pivotal role in the regulation of insulin secretion in the mouse pancreas.     

2018年中国植物科学若干领域重要研究进展

2018年中国植物科学继续呈现快速发展的态势, 我国科学家在国际植物科学主流学术刊物发表论文数量大幅增加, 取得了多项具有重要影响的成果。调控植物生长-代谢平衡实现可持续农业发展入选2018年度中国科学十大进展; 中国被子植物区系进化历史研究入选2018年度中国生命科学十大进展。以水稻为代表的农作物和果蔬等经济作物研究在国际上已呈现出明显的优势, 若干领域已从“追赶”状态跨越到“领跑”地位。该文对2018年中国科学家在植物科学若干领域取得的重要研究成果进行了概括性评述, 旨在全面追踪和报道当前中国植物科学领域的发展前沿和热点, 展示中国科学家所取得的杰出成就。     

我国葫芦科植物离体培养研究进展

葫芦科植物包括多种瓜类蔬菜,对其进行离体培养研究具有重要的理论和实践意义.综述了国内在葫芦科植物器官培养、体细胞胚胎发生、花药培养、原生质体培养和体细胞杂交及离体遗传转化等方面取得的研究进展,并对葫芦科植物离体培养、遗传转化与育种的前景作了展望.     

我国葫芦科植物离体培养研究进展

葫芦科植物包括多种瓜类蔬菜,对其进行离体培养研究具有重要的理论和实践意义。综述了国内在葫芦科植物器官培养、体细胞胚胎发生、花药培养、原生质体培养和体细胞杂交及离体遗传转化等方面取得的研究进展,并对葫芦科植物离体培养、遗传转化与育种的前景作了展望。     

Changes in aquatic vegetation in Rhine floodplain streams in Alsace in relation to disturbance

Abstract. Changes are described in aquatic vegetation in oligotrophic, groundwater-fed Rhine floodplain streams in Alsace (eastern France), resulting from disturbance. Disturbance factors include changes in nutrients, either permanent ones - effluent from a waste water treatment plant or trout hatcheries - or periodic ones: flooding. Regular inputs of high levels of phosphate and ammonia modified the macrophyte vegetation in these streams. The floristic composition, which was characteristic of oligotrophic waters upstream of the eutrophicated sector, changed to that of a eutrophic situation as originally found downstream. Periodic disturbance by floods which normally occur once a year, irregularly eutrophicates the small streams, causing the development of a mixture of eutrophic and oligotrophic species. Six macrophyte communities are distinguished, indicating different trophic levels. The aquatic vegetation is adapted to the variations of phosphate and ammonia levels. Hence, aquatic macrophytes can be used as bio-indicators of fluctuations in water nutrient levels in relation to the type of disturbance.     

Morphine-potentiated platelet aggregation in in vitro and platelet plug formation in in vivo experiments

The detailed mechanisms underlying morphine-signaling pathways in platelets remain obscure. Therefore, we systematically examined the influence of morphine on washed human platelets. In this study, washed human platelet suspensions were used for in vitro studies. Furthermore, platelet thrombus formation induced by irradiation of mesenteric venules with filtered light in mice pretreated with fluorescein sodium was used for an in vivo thrombotic study. Morphine concentration dependently (0.6, 1, and 5 microM) potentiated platelet aggregation and the ATP release reaction stimulated by agonists (i.e., collagen and U46619) in washed human platelets. Yohimbine (0.1 microM), a specific alpha(2)-adrenoceptor antagonist, markedly abolished the potentiation of morphine in platelet aggregation stimulated by agonists. Morphine also potentiated phosphoinositide breakdown and intracellular Ca(2+) mobilization in human platelets stimulated by collagen (1 microg/ml). Moreover, morphine (0.6-5 microM) markedly inhibited prostaglandin E(1) (10 microM)-induced cyclic AMP formation in human platelets, while yohimbine (0.1 microM) significantly reversed the inhibition of cyclic AMP by morphine (0.6 and 1 microM) in this study. The thrombin-evoked increase in pH(i) was markedly potentiated in the presence of morphine (1 and 5 microM). Morphine (2 and 5 mg/g) significantly shortened the time require to induce platelet plug formation in mesenteric venules. We concluded that morphine may exert its potentiation in platelet aggregation by binding to alpha(2)-adrenoceptors in human platelets, with a resulting inhibition of adenylate cyclase, thereby reducing intracellular cyclic AMP formation followed by increased activation of phospholipase C and the Na(+)/H(+) exchanger. This leads to increased intracellular Ca(2+) mobilization, and finally potentiation of platelet aggregation and of the ATP release reaction.     

Progress in glial cell studies in some laboratories in China

Glial cells in the central nervous system(CNS) consist of a heterogeneous population of cell types,each characterized by distinct morphological features,physiological properties,and specific markers.In contrast to the previous view that glial cells were passive elements in the brain,accumulating evidence suggests that glial cells are active participants in various brain functions and brain disorders.This review summarizes recent progress of glial cell studies from several groups in China,ranging from studie...