耐辐射异常球菌dlp基因缺失突变株构建及其生物学功能研究

耐辐射异常球菌(Deinococcus radiodurans,DR)因其具有对非生物胁迫超强的抵抗能力而备受关注。旨在了解该菌亲水蛋白Dlp在细胞耐受非生物胁迫中的作用,采用融合PCR和基因同源重组技术,获得了dlp基因缺失突变株Δdlp,对野生型DR及突变株Δdlp进行非生物胁迫。结果表明,dlp的缺失导致DR细胞对高盐和氧化胁迫敏感。体外检测氧化胁迫条件下Dlp蛋白对苹果酸脱氢酶(MDH)和乳酸脱氢酶(LDH)活性的保护,结果显示,Dlp蛋白的加入能缓解氧化胁迫条件下MDH、LDH酶活性的损失。由此表明,亲水蛋白Dlp增强了耐辐射异常球菌对非生物胁迫的抗性,并能以类似分子伴侣的形式保护胁迫条件下酶的活性。     

核黄素参与水稻非生物胁迫响应的分析

为探究核黄素在水稻非生物胁迫响应中的作用,以粳稻Kitaake和籼稻T98B为试验材料,考察了核黄素对2种材料的盐、高温、渗透、碱和氧化胁迫响应的影响,重点测定了盐和高温胁迫下水稻体内核黄素合成基因的表达和相关生理指标。结果表明,(1)施加外源核黄素有效提高了2种水稻材料的盐和高温胁迫耐受性,降低了渗透胁迫耐受性,而其氧化和碱胁迫耐受性不受影响。(2)逆境胁迫均不同程度地促进了核黄素在2种水稻材料中的积累,尤其在盐和高温胁迫下促进效果最明显。(3)盐和高温胁迫均诱导了核黄素合成酶基因的表达,促进了核黄素的生物合成,改善了水稻的胁迫耐受性。研究表明,非生物逆境胁迫能促进核黄素在水稻体内的合成和积累,外源核黄素也能明显提高水稻对盐和高温胁迫的耐受性,但却降低了其对渗透胁迫的耐受性。     

铁蛋白DrfE对耐辐射异常球菌抗氧化酶活性的影响

为研究耐辐射异常球菌(Deinococcus radiodurans)中drf E编码的铁蛋白Drf E的功能,通过基因回补试验构建drf E基因的回补菌株(pdrf E∷Δ),对野生型WT、突变株Δdrf E及回补菌株pdrf E∷Δ进行不同浓度H_2O_2和Na Cl胁迫,分别测定野生型WT、突变株Δdrf E和回补菌株pdrf E∷Δ体内Fe2+含量及抗氧化酶类活性。结果显示,drf E基因缺失导致菌株对氧化和盐胁迫敏感,该基因的回补能够恢复菌株对氧化和盐胁迫的抗性。drf E基因缺失导致耐辐射异常球菌体内Fe2+浓度由232μmol/L增加至293μmol/L;80 mmol/L H_2O_2处理30 min后,突变株Δdrf E的CAT活性下降32.74%,SOD下降41.3%。以上结果表明Drf E蛋白可能参与耐辐射异常球菌铁代谢途径,并且在细胞抗氧化体系中发挥重要作用。     

基因芯片技术分析转SlNAC10基因拟南芥非生物胁迫相关差异表达基因

NAC(NAM、ATAF1/2和CUC2)转录因子是植物特有的转录调控因子,在植物的器官建成、生长发育以及抵御非生物胁迫等方面发挥着至关重要的作用。该文利用基因芯片技术筛选转Sl NAC10基因拟南芥和野生型拟南芥非生物胁迫抗性相关差异表达基因,并通过实时荧光定量PCR对部分差异表达基因进行验证。芯片结果显示,差异表达2倍以上的基因有4 054个,其中与非生物胁迫相关基因有15个,与非生物胁迫相关的转录因子基因有14个,这些基因参与应答渗透胁迫、响应高盐、冷、热、高光强等胁迫。对差异表达2倍以上的基因进行GO(Gene Ontology)分析和KEGG(Kyoto Encyclopedia of Genes and Genomes)分析,发现这些基因在非生物胁迫相关的13个注释中富集,涉及相关代谢途径96个,其中包括植物激素信号转导、精氨酸和脯氨酸代谢、吲哚生物碱合成、谷胱甘肽代谢等。以上结果表明,SlNAC10可直接或间接调控多种下游基因的表达,提高植物抵御非生物胁迫的能力。     

茶树NAC转录因子基因CsNAC79和CsNAC9鉴定及其对非生物胁迫的响应

【目的】鉴定茶树NAC转录因子基因CsNAC79和CsNAC9,并分析它们在干旱、盐、高温、低温、外施ABA和外施GA₃胁迫下的表达模式,为进一步解析CsNAC79和CsNAC9转录因子的生物学功能提供参考。【方法】以茶树‘龙井43’为材料,用RT-PCR扩增NAC转录因子家族基因CsNAC79和CsNAC9,并进行生物信息学分析;用qRT-PCR检测CsNAC79和CsNAC9在茶树6种非生物胁迫下的相对表达量。【结果】(1)CsNAC79和CsNAC9分别编码409个和282个氨基酸,且分别在15—150氨基酸位点、11—134氨基酸位点含有NAC家族成员典型的NAM保守结构域。(2)CsNAC79蛋白与中华猕猴桃、柿、洋蓟亲缘关系较近,CsNAC9蛋白与桃、荔枝、榴莲亲缘关系较近;2个NAC转录因子均是亲水性蛋白,皆不含信号肽和跨膜结构;CsNAC79和CsNAC9的启动子区域都含有非生物胁迫响应元件;蛋白质空间结构分析显示,CsNAC79和CsNAC9蛋白主要是由不规则卷曲和α-螺旋组成。(3)表达分析表明：CsNAC79和CsNAC9基因在6种不同非生物...     

甘菊木质素调控转录因子ClSND1-like的克隆与表达分析

为了探索纤维特异表达的NAC类转录因子SND1(secondary wall-associated NAC domain protein1,SND1)在甘菊(Chrysanthemum lavandulifolium)生长发育及非生物胁迫中的作用,该研究从甘菊中克隆了ClSND1-like基因,并对其进行生物信息学、亚细胞定位及表达模式分析。结果发现:(1)ClSND1-like基因的编码区全长1185 bp,共计编码394个氨基酸,是一个不稳定的亲水性蛋白,与除虫菊基因亲缘关系较近。(2)亚细胞定位结果表明,ClSND1-like基因在叶中不表达,在茎的导管壁上特异表达,属于木质素特异表达基因。(3)实时荧光定量PCR结果发现,ClSND1-like基因在茎中表达量最高,在根和叶中表达量极低,且随着茎秆的老化,表达量逐渐升高;在渗透胁迫和盐胁迫中表达量均显著提高。研究推测,ClSND1-like基因与甘菊木质素形成相关,并参与调控植物生长及盐和渗透胁迫。该结果为ClSND1-like基因在甘菊生长和非生物胁迫抗性中的研究奠定了基础,也为菊属植物的生长及抗性研究提供了新思路。     

水稻OsRPL36A基因的表达特性研究

【目的】核糖体蛋白（ribosomal protein,RP）是参与蛋白质合成及基因表达调控的一种重要因子,在植物生长发育和胁迫响应过程中具有重要的作用。研究在水稻中克隆了1个核糖体蛋白家族基因OsRPL36A,并对其生物学功能进行初步研究,为后续OsRPL36A基因功能研究提供理论依据和研究方向。【方法】利用生物信息学技术分析OsRPL36A基因结构、顺式作用元件和演化过程;同时利用实时荧光定量PCR（quantitative real-time PCR,qRT-PCR）技术分析OsRPL36A的组织表达特异性、节律表达模式、及其对不同激素和非生物胁迫的响应情况。【结果】（1）OsRPL36A的编码区全长为297 bp,共编码98个氨基酸,属于核糖体蛋白L36超基因家族。（2）OsRPL36A的启动子区包含3个节律表达相关元件、10个光响应元件、14个激素响应元件和27个环境胁迫响应元件。（3）OsRPL36A在叶片中的表达量相对高于其他组织;具有典型的节律表达模式;且受IAA、高温、低温和渗透胁迫等诱导表达。【结论】OsRPL36A在叶中高表达,具有典型节律表达模式,对IAA显著响应,可能参与热激、低温、盐害和渗透胁迫响应。     

AsSlt2基因对茄链格孢细胞壁完整性的调控

【背景】由茄链格孢(Alternaria solani)引起的马铃薯早疫病被普遍认为是马铃薯生产上的第二大叶部病害,在马铃薯各产区普遍发生,给马铃薯生产造成了巨大的经济损失。【目的】明确AsSlt2基因对茄链格孢细胞壁完整性的影响。【方法】在含有刚果红、细胞壁降解酶和十二烷基硫酸钠(sodiumdodecylsulfate,SDS)等细胞壁胁迫的培养基上观察ΔAsSlt2缺失突变株的生长情况,计算相对生长抑制率;通过实时荧光定量PCR (RT-qPCR)方法检测ΔAsSlt2菌株中细胞壁合成相关基因的表达情况;进一步检测ΔAsSlt2细胞壁中几丁质的含量及胞外酶活性。【结果】ΔAsSlt2缺失突变株对SDS、刚果红、细胞壁降解酶等细胞壁胁迫的敏感性增强,在加入细胞壁降解酶后突变株原生质体释放量显著增多;ΔAsSlt2对外源氧胁迫更敏感,突变株胞外过氧化物酶和漆酶活性均显著降低;进一步研究发现,ΔAsSlt2细胞壁中几丁质含量减少,几丁质合成相关基因与漆酶合成相关基因的表达量均明显降低。【结论】AsSlt2基因在茄链格孢细胞壁的完整性及抵御外界胁迫方面发挥重要作用。     

粤蓝链霉菌榴菌素生物合成基因orf20的功能

【目的】在大肠杆菌中,转录因子SoxR作为胞内氧化还原感应器,参与抗氧化胁迫的全局性调控。粤蓝链霉菌榴菌素生物合成基因簇内存在一个类soxR基因orf20,但其生理功能仍不清楚。【方法】将orf20基因在大肠杆菌中进行表达,分析携带重组质粒的大肠杆菌对百草枯抗性的变化。同时通过修改后的PCR-targeting方法构建粤蓝链霉菌orf20删除的突变株,分析突变株的表型变化和对百草枯抗性水平的变化。【结果】重组ORF20在羧基端含有组氨酸标签,并在大肠杆菌中获得可溶性表达,携带重组质粒pET28b-orf20的大肠杆菌对百草枯的抗性水平显著提高。粤蓝链霉菌orf20删除突变株仍具有产孢能力,生长特性没有改变,对百草枯的抗性水平也没有变化,但榴菌素的产量大幅提高,是野生株的3.3倍。【结论】在大肠杆菌中,orf20基因的编码产物能够被百草枯激活,替代SoxR参与抗氧化胁迫的调控。在粤蓝链霉菌中,orf20基因不参与抗氧化胁迫,而对榴菌素的产生有负调控效应。     

基因芯片技术筛选转SlNAC1基因拟南芥差异表达基因

研究已表明植物特有的一些NAC(NAM,ATAF1/2,CUC2)转录因子可提高植物抗逆性,利用基因芯片技术筛选转SlNAC1基因拟南芥与野生型拟南芥间差异表达基因,能够为研究转基因拟南芥非生物胁迫抗性相关基因提供依据。结果显示,在转SlNAC1基因拟南芥43 604个基因中有3 046个差异表达2倍以上的基因。对差异表达5倍以上基因经过GO富集度统计学分析表明,细胞组分相关基因占33.05%;分子功能相关基因占33.95%;生物学过程相关基因占33.00%。对差异表达2倍以上基因进行KEGG信号通路分析,结果表明有2 431个基因涉及到88个不同的信号通路。通过筛选获得转基因拟南芥非生物胁迫抗性相关候选基因,为后续研究NAC转录因子的下游基因及其调控网络的构建提供方向和理论支撑。     

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.     

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。     

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。     

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.     

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.     

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...     

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.