植食性昆虫唾液效应子和激发子的研究进展

植食性昆虫与寄主植物通过协同进化形成了复杂的防御和反防御机制。本文系统综述了昆虫唾液效应子和激发子在植物与昆虫互作中的作用及机理。昆虫取食中释放的唾液激发子被植物识别而激活植物早期免疫反应,昆虫也能从口腔分泌效应子到植物体内抑制免疫;抗性植物则利用抗性(R)蛋白识别昆虫无毒效应子,启动效应子诱导的免疫反应,而昆虫又进化出多种方式来躲避植物R蛋白的识别。总之,在这场军备竞赛中,昆虫的唾液成分决定着昆虫能否取食成功。取食过程中,咀嚼式口器害虫分泌大量酶类到植物体内,而刺吸式害虫则分泌胶状和水样唾液到植物中,它们都利用激发子和效应子去调控植物的免疫防御反应。分析现已报道的昆虫效应子发现其作用机制各有不同,具体表现为影响植物早期防御信号,调控植物激素通路及其他通路,或靶向小分子RNA通路。本文还综述了昆虫激发子的最新进展,揭示激发子可以通过诱导释放植物次生代谢物以及调控激素水平、Ca²⁺内流和活性氧爆发增强植物抗性。最后对昆虫效应子的分泌特性、寄主特异性和多功能性作了分析,并对无毒效应子及其对应的植物R基因,以及激发子的模式识别受体的研究进行了展望。     

植食性昆虫利用唾液腺适应寄主植物防御机制研究进展

植食性昆虫与寄主植物在长期协同进化的历程中,两者逐渐演化出丰富多样的防御与反防御机制,其中在植食性昆虫适应植物防御的过程中,唾液腺分泌物起到关键性的作用。本研究从宏观与微观两个层面,揭示植食性昆虫如何利用唾液腺以适应寄主植物防御的作用机理。回顾了昆虫唾液腺分泌物通过干预植物气孔的动态变化、适应植物细胞壁、降解植物防御性化合物等方式调控寄主植物防御的研究进展,探讨了昆虫唾液效应因子以干扰植物早期免疫信号通路、调节植物激素信号通路、与植物免疫蛋白互作等形式应对植物防御反应的内在分子机制。同时,本文依据CRISPR/Cas9、植物介导的RNAi、纳米材料介导的RNAi等新技术的发展,对基于昆虫效应因子开发的虫害防控技术的发展空间进行分析,以期为作物抗性的提高以及害虫综合治理能力的提升提供理论依据与实践指导。     

寄主植物与刺吸式昆虫互作防御的研究进展

寄主植物与昆虫在长期协同进化中形成了复杂的防御和反防御机制。本文系统综述了寄主植物与刺吸式昆虫互作防御的过程与机制。刺吸式昆虫利用特化的口针,吸食寄主植物组织汁液时,植物通过细胞膜表面或细胞内受体感知昆虫取食信号,并经过丝裂原活化蛋白激酶(mitogen-activated protein kinase, MAPK)信号通路、植物激素信号通路、钙离子信号通路、转录因子调控、Rop/Rac GTPase信号通路、活性氧(reactive oxygen species, ROS)通路等信号转导通路激活植物免疫。为了阻止害虫进一步取食,寄主植物形成了增强的物理屏障,并诱导产生次生代谢物、抗营养酶类、抗消化酶类和胼胝质沉积及释放挥发物等多种防御机制。在与寄主植物“博弈”的过程中,刺吸式昆虫往往会利用其取食时分泌的唾液成分,靶向植物靶标蛋白,通过破坏宿主植物的物理屏障,或抑制宿主植物的抗性信号转导,或抑制宿主次生代谢物的毒害作用,或通过跨界RNA和水平基因转移等方式抑制植物的防御反应,从而达到继续取食为害的目的。此外,基于植物与病原菌互作模式,结合寄主植物与刺吸式昆虫互作研究进展,总结了寄主植物...     

昆虫取食诱导的植物防御反应

植物被昆虫取食后可产生直接防御或间接防御。直接防御通过增加有毒的次生代谢产物或防御蛋白对昆虫生理代谢产生不利的影响,但对植物的消耗较大。间接防御通过释放挥发性化合物吸引天敌昆虫,并以此控制植食性昆虫。特异性的昆虫激发子(insect specific elicitors)能够诱导挥发性化合物的释放。多种信号途径参与昆虫取食诱导的植物防御反应,它们之间的相互作用协同或拮抗。了解昆虫取食诱导的植物防御反应,对于害虫综合治理策略的完善具有重要的意义。     

植物与植食性昆虫相互作用的分子机制

在长期的协同进化中,植物建立起应对昆虫取食为害的精密而又复杂的防御机制,植物转录组调控中防御应答基因的表达及防御物质的合成因不同的昆虫取食方式而异。一般来说,咀嚼式口器昆虫取食时造成大面积组织伤害,可诱导植物产生伤害反应;而刺吸式口器昆虫因其特殊的口针取食,诱导植物激活病原体相关的防御途径。不同的防御途径激活不同的识别机制和信号途径。本文从信号识别和转导上综述了不同食性的昆虫取食植物时所引发的防御反应,分析了昆虫-植物相互作用关系的分子机制。     

韧皮部取食昆虫诱导的植物防御反应

刺吸式昆虫与寄主植物之间具有特殊的生物互作关系。本文对刺吸式昆虫取食韧皮部诱导的植物防御反应类型、 防御物质变化、 信号途径以及植物反应转录组学研究等方面进行综述。韧皮部取食昆虫取食诱导的植物防御反应机制主要包括： (1)改变自身的营养状况; (2)产生有毒的次生化合物; (3)产生防御蛋白。防御反应与植物水杨酸、 茉莉酸、 乙烯等信号分子密切相关。研究表明, 刺吸式昆虫取食诱导的植物防御反应主要引发以水杨酸为主的信号途径, 但相关分子互作机制还有待明确。日益丰富的基因组资源和不断发展的分子生物学技术为揭示植物防御反应中信号分子的作用机制、 找出植物内生抗性的特异因子以及阐明诱导防御机制奠定了基础。了解刺吸式昆虫取食诱导的植物防御反应, 为深入理解植物-昆虫间协同进化关系提供了依据, 为害虫治理和抗虫植物的培育提供了新的思路。     

蚜虫诱导的植物免疫反应

在植物与昆虫长期的互作过程中,植物建立起一系列精密而又复杂的防御机制以应对昆虫取食为害,并且能够识别不同取食类型昆虫的效应因子作出不同的防御应答。最近研究揭示了许多植物与蚜虫之间相互抗争的分子机制,这不仅包括植物激素介导的诱导防御途径、植物先天免疫系统和基于gene-for-gene的R抗性识别和作用机制,而且还包括蚜虫在取食过程中分泌的唾液成分,它有助于蚜虫取食韧皮部组织,抑制植物病原相关分子模式激活的免疫反应(Pathogen-associated molecular patterns triggered immunity,PTI)防御,以及被植物核苷酸结合位点区-亮氨酸重复序列区(NBS-LRR)膜受体识别激活效应因子免疫反应(ETI)防御等方面。本文综述了蚜虫诱导的植物防御途径、蚜虫诱导的植物免疫反应、蚜虫效应因子的鉴定与功能分析三方面的最近研究进展,提出了未来发展的研究方向。这些基于病原微生物提出的"zig-zag"模型为进一步理解植物先天免疫、诱导防御系统和蚜虫唾液腺组分的互作提供新理论支撑,为揭示了植物与蚜虫抗性互作的分子机制及有效安全地防治害虫提供了新思路。     

蚜虫诱导的植物免疫反应

在植物与昆虫长期的互作过程中,植物建立起一系列精密而又复杂的防御机制以应对昆虫取食为害,并且能够识别不同取食类型昆虫的效应因子作出不同的防御应答。最近研究揭示了许多植物与蚜虫之间相互抗争的分子机制,这不仅包括植物激素介导的诱导防御途径、植物先天免疫系统和基于gene-for-gene的R抗性识别和作用机制,而且还包括蚜虫在取食过程中分泌的唾液成分,它有助于蚜虫取食韧皮部组织,抑制植物病原相关分子模式激活的免疫反应(Pathogen-associated molecular patterns triggered immunity,PTI)防御,以及被植物核苷酸结合位点区-亮氨酸重复序列区(NBS-LRR)膜受体识别激活效应因子免疫反应(ETI)防御等方面。本文综述了蚜虫诱导的植物防御途径、蚜虫诱导的植物免疫反应、蚜虫效应因子的鉴定与功能分析三方面的最近研究进展,提出了未来发展的研究方向。这些基于病原微生物提出的"zig-zag"模型为进一步理解植物先天免疫、诱导防御系统和蚜虫唾液腺组分的互作提供新理论支撑,为揭示了植物与蚜虫抗性互作的分子机制及有效安全地防治害虫提供了新思路。     

虫害诱导植物间接防御反应的激发与信号转导途径

植物通过产生和释放挥发性物质增加植食性昆虫的天敌对其寄主或猎物的定位,减少植食性昆虫对植物的取食,从而达到间接防御的目的。植物对植食性昆虫所做出间接防御反应激发因子和信号转导途径的研究,对应用虫害诱导植物挥发物引诱害虫天敌,并进一步从植物、植食性昆虫及其天敌间三级营养关系,研究动植物协同进化机理和病虫害防治具有深远意义。本文根据国内外最新研究进展,对虫害诱导植物间接防御反应的激发因子,昆虫取食信号的转导途径及对植物间接防御相关基因的激活等方面进行了系统地综述。     

应用鸟枪法LC-MS/MS鉴定烟粉虱唾液蛋白

烟粉虱是一种刺吸式口器小型昆虫,每年对我国农业生产造成巨大危害。烟粉虱在取食植物时分泌多种唾液蛋白帮助其取食,同时唾液中的效应因子在调控植物防御反应过程中发挥重要作用。由于烟粉虱个体微小,唾液收集十分困难,有关其唾液蛋白的研究难以开展。本研究收集了3万头烟粉虱唾液,利用高精度Q-Exactive质谱,采用shotgun的方法首次鉴定了烟粉虱唾液中蛋白组分。应用双层膜收集装置收集到的烟粉虱唾液经浓缩等处理后其蛋白浓度约为1.698 g/L。唾液蛋白样品经胶内酶解、LC-MS/MS检测、序列分析,最终鉴定出42个烟粉虱唾液蛋白。功能分析表明烟粉虱唾液蛋白组分与蚜虫唾液蛋白组分具有一定的相似性,但多数蛋白为功能未知蛋白。通过质谱鉴定烟粉虱唾液蛋白组分为深入研究烟粉虱唾液蛋白的功能奠定了基础,有利于明确烟粉虱危害寄主植物的分子机制,为开发害虫防治新方法提供新思路。     

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.     

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。     

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。     

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。     

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.     

Apoptosis in experimental myocardial infarction in situ and in the perfused heart in vitro

We report the appearance of apoptotic cells in experimental myocardial infarction (rabbit heart) in in situ and in vitro preparations. Apoptosis was recognized by intravital staining with Hoechst 33342 (Ho342), by nick-end labeling (TUNEL) and by DNA laddering. A steady rise in the relative number of apoptotic cardiomyocytes (apoptotic index) was noted in in situ preparations. Apoptosis was first noted 6 h after the onset of ischemia with its highest value occurring after 72 h. Apoptotic nuclei were absent in remote areas of the left and right ventricles. Apoptotic nuclei within the infarcted area showed diminished intensity of Ho342 fluorescence. Three days after ischemia, a border zone adjacent to the infarcted area consisting of apoptotic macrophages was recognized. A novel finding was the appearance of apoptotic cardiomyocytes in the isolated perfused ischemic heart. Occurring as early as 50 min after the onset of ischemia, a high apoptotic index was present adjacent to the ligature placed around the coronary artery. This observation provides the opportunity to selectively examine factors leading to apoptosis in the ischemic heart under controlled experimental conditions.