反义酸性转化酶基因低温贮藏马铃薯块茎还原糖和淀粉含量的影响

对2个含有酸性转化酶(AcInv)反义基因的转基因马铃薯品系及对照品种进行低温贮藏(4℃)及室温还暖处理.随低温贮藏时间的延长,供试材料均表现出还原糖含量升高,总淀粉含量下降的趋势.低温处理40 d时,"Ac转Atlantic"和"Ac转甘农薯2号"的还原糖含量比未转基因品种低23%和18%.总淀粉含量分别比未处理前下降约1.0%和1.3%,支链淀粉含量分别下降约1.4%和1.7%,淀粉直/支比明显低于对照,分别为0.29和0.38.块茎的石蜡切片显示,转基因块茎中深蓝色淀粉颗粒明显少于未转基因对照.另外,对低温贮藏的块茎室温还暖后,2个转基因品系的还原糖含量仍低于对照品种.实验结果证明反义AcInv基因对低温贮藏下块茎还原糖和淀粉含量具有下向调节作用.     

利用ihpRNA介导的基因沉默培育抗冷糖化马铃薯

为培育抗冷糖化的转基因马铃薯材料,克隆了368 bp的马铃薯酸性转化酶(AcInv)基因3′端非翻译区(3′UTR)和281 bp的马铃薯VP1-ABI3-like protein基因的第一内含子,构建了内含子连接的马铃薯AcInv基因3′UTR的发夹型RNA(ihpRNA)载体pBIV;采用微束激光穿刺技术转化马铃薯品种,得到了149个转基因株系,其中139个转基因株系在低温贮藏35 d时块茎还原糖含量低于亲本材料。RT-PCR分析表明还原糖含量降低的转基因植株中检测不到AcInv基因mRNA的积累。本研究结果表明以3′UTR作为RNAi载体的干涉片段可以有效地抑制靶标基因mRNA的积累,通过对AcInv沉默可获得抗低温糖化的马铃薯育种材料。     

串番茄与普通番茄果实贮藏期间几种与果实品质相关指标的变化比较

随着贮藏时间的延长,串番茄果实硬度、果肉硬度和有机酸含量均下降,糖酸比升高,风味由酸变甜,但这些指标的变化幅度均小于普通番茄。贮藏前、中期,两种番茄果实的还原糖含量变化较一致;贮藏末期,普通番茄的还原糖含量急剧下降,而串番茄则略有回升。不同品种番茄果实中维生素C（Vc）含量变化差异较大,均呈先升高后下降的趋势。普通番茄及串番茄品种‘ST03’的Vc含量变化幅度较小,而串番茄品种‘ST02’和‘ST04’变化幅度较大。     

利用烟草蔗糖酶同系抑制物异位表达防止低温引起的马铃薯块茎甜化

Nature Biotechnology1999年17卷7期报道:为防止马铃薯块茎在贮藏期间发芽常利用可延长休眠的化学制剂处理块茎,或将块茎贮藏于低温.但低温贮藏常使块茎内的淀粉裂解转化为可溶糖--己糖.这种现象称为"低温诱发的马铃薯块茎甜化".己糖与自由氨基酸发生的反应,可给马铃薯块茎的加工品质带来负面的影响.     

海南地区种植不同菊芋品种的生长指标和糖分组成分析及适宜品种筛选

对种植于海南地区的不同菊芋(Helianthus tuberosus Linn.)品种的生长指标和糖分组成进行比较和分析,并筛选出适宜海南地区种植的菊芋品种。结果表明:随着时间的推移,6个菊芋品种的株高、茎粗、单株地上部干质量、单株根干质量及单株总干质量总体上呈逐渐升高的趋势,而根长的变化趋势各异。10月26日(成熟期),‘泰芋1号’(‘Taiyu No.1’)的株高和茎粗最高,‘南芋9号’(‘Nanyu No.9’)的根长以及块茎和茎干的产量、单株鲜质量和含水率最高,‘南芋1号’(‘Nanyu No.1’)的单株地上部干质量、单株块茎干质量及单株总干质量最高,‘青芋2号’(‘Qingyu No.2’)的单株根干质量最高。随着时间的推移,6个菊芋品种叶片中可溶性糖含量的变幅相对较小,而茎干中可溶性糖含量则总体上呈逐渐降低的趋势;6个菊芋品种叶片和茎干中还原糖含量的变化趋势各异。10月26日,‘南芋9号’叶片中可溶性糖含量最高,6个菊芋品种间叶片中还原糖含量差异不显著,‘泰芋1号’茎干中可溶性糖和还原糖含量最高;‘南芋1号’、‘南芋9号’、‘泰芋1号’和‘泰芋2号’(‘Taiyu No.2’)块茎中可溶性糖含量较高,‘青芋2号’、‘泰芋2号’和‘泰芋3号’(‘Taiyu No.3’)块茎中还原糖含量较高。随着时间的推移,‘南芋1号’、‘南芋9号’和‘青芋2号’叶片和茎干中果糖含量总体上呈逐渐升高的趋势,‘泰芋1号’、‘泰芋2号’和‘泰芋3号’叶片和茎干中果糖含量均呈先降低后升高的趋势;6个菊芋品种叶片中葡萄糖含量总体上呈逐渐升高的趋势,而茎干中葡萄糖含量总体上呈先降低后升高的趋势;6个菊芋品种叶片和茎干中蔗糖含量的变化趋势各异。总体上看,同一时期6个菊芋品种间叶片和茎干中蔗果三糖、蔗果四糖和蔗果五塘含量的差异均不显著。综合研究结果显示:适宜在海南地区种植的菊芋品种为‘南芋1号’和‘南芋9号’。     

木薯高、低粉品种贮藏根生长关键期的生理生化特性比较

通过研究木薯Manihot esculenta高粉和低粉品种贮藏根在发育关键期(形成–膨大期)主要生理生化性质的差异及其动态变化，为木薯栽培管理和育种改良提供理论基础。对高粉木薯品种‘辐选01’(FX01)和‘Kasetsart 50’(KU50)以及低粉品种‘华南124’(SC124)和‘9I’于种植后120、130、140、151和165 d五个时期分别取贮藏根样品，测定淀粉、可溶性糖、脱落酸(ABA)、保护酶、活性氧(ROS)、丙二醛(MDA)等生理生化指标并分析变化规律。结果表明，可溶性糖含量在贮藏根皮层中始终高于淀粉储藏区；高粉品种中总可溶性糖含量在贮藏根膨大期快速增加，且表现出较高的抗氧化酶活性和较低的ROS及MDA含量；ABA含量呈现出高粉品种比低粉品种低的趋势。木薯低粉和高粉品种中可溶性糖的分布与其转运后合成淀粉的规律相一致，高粉品种中淀粉的积累速率始终高于低粉品种，其较高的抗氧化酶活性和较低的ROS及MDA含量有利于木薯贮藏根中淀粉的积累。     

外引马铃薯块茎品质与贮藏时间的影响研究

分析10份外引马铃薯块茎在贮藏期间营养物质变化,以期为引种马铃薯后期的生产应用提供科学依据。结果表明：AGRICO-10、AGRICO-6、AGRICO-8这3个品种在长期贮藏时其淀粉含量较高。AGRICO-10、AGRICO-5、AGRICO-7这3个品种可溶性糖含量损失率较低,干物质含量较高,具有很高的长期贮藏价值。AGRICO-4、AGRICO-1在整个贮藏期间还原糖含量较低,建议用于马铃薯油炸类食品的生产,但二者由于贮藏期间淀粉损失率较高,因此不易贮藏。AGRICO-10、AGRICO-9、AGRICO-6这3个品种在贮藏期间蛋白质含量较高。     

萌发马铃薯中PFP的初步研究

马铃薯块茎采收后,需要经过一段休眠期才能在适宜的条件下萌发。马铃薯块茎中干重的70—75％是淀粉。淀粉、蔗糖、还原糖,三者在休眠期保持一定的动态平衡。当块茎临近萌发时,蔗糖和还原糖的水平开始上升。其他物质,特别是氨基酸、蛋白质类,在萌发过程中含量增高。与之相对应的酶系统也日趋活跃。马铃薯块茎萌发过程是消耗并利用贮存物质,不断合成新物质,组建新组织和新器官过程。因此贮藏的淀粉一方面“燃烧”,提供能量;另一方面进行分解,提供合成新物质的     

PVY和PVS病毒复合侵染对马铃薯光合及营养品质的影响

以2个马铃薯高代品系为实验材料,研究马铃薯病毒Y(PVY)和S(PVS)复合侵染对马铃薯叶片SPAD值、最大净光合速率、表观量子效率、气孔导度、暗呼吸速率、蒸腾速率、光补偿点、胞间CO_2浓度和饱和光强等光合参数,以及马铃薯块茎产量、干物含量、淀粉含量、还原糖含量、粗蛋白含量等产量品质指标的影响。结果表明:(1)田间受到PVY和PVS病毒复合侵染后,马铃薯品系2010-11植株的叶片PVS病毒含量显著低于品系34-2植株,2010-11植株的叶片PVY病毒含量同样低于品系34-2植株,但差异不显著。(2)与对照相比,感病后马铃薯品系34-2和2010-11的平均单株产量分别显著降低48.54%和19.98%,淀粉含量分别降低8.06%和3.38%,但不显著;粗蛋白含量分别显著升高14.05%和29.17%;还原糖含量分别显著降低11.11%和14.29%;34-2干物量含量显著降低6.9%,2010-11干物质含量略降低0.66%。(3)两品系感病植株的光合参数SPAD值分别显著降低13.37%、20.10%;最大净光合速率分别显著降低32.48%和4.54%;其它光合参数变化没有规律性。研究发现,PVY和PVS病毒混合侵染使马铃薯植株叶片叶绿素含量显著降低,进而影响光合作用的正常进行;病毒侵染使块茎中还原糖和淀粉的积累显著受到抑制,但能够促进块茎中粗蛋白的含量显著提高。     

山药异淀粉酶基因克隆及其在淀粉代谢中的作用北大核心CSCD

为了明确异淀粉酶基因(ISA 3)在山药淀粉代谢中的作用,该研究以‘毕克齐’和‘大和长芋’山药为试验材料,测定了块茎中淀粉及组分含量和异淀粉酶活性等;采用RT-PCR技术克隆了ISA 3,并进行生物学分析及山药块茎不同膨大期和不同组织间ISA 3基因的表达等。结果表明:(1)山药‘大和长芋’的直链淀粉、支链淀粉和总淀粉含量均显著高于‘毕克齐’,且两品种的淀粉含量随生长发育的变化均呈先升高后降低的趋势,并均于种植后120 d时达到最高,但‘毕克齐’的异淀粉酶(ISA)活性在整个膨大期均高于‘大和长芋’。(2)成功克隆获得山药ISA 3开放阅读框长1584 bp,编码527个氨基酸;ISA3为亲水性蛋白。(3)不同品种块茎在膨大时期的ISA 3基因表达趋势不同,‘毕克齐’中呈先显著上调随后下调,而在‘大和长芋’中表达总体下调,且在山药的叶、茎和块茎中均有表达,存在明显的组织特异性。(4)ISA活性与山药淀粉及支链淀粉含量呈显著和极显著正相关关系,但ISA活性与ISA 3的表达量呈负相关关系。研究表明,异淀粉酶参与了山药块茎中淀粉的合成,且主要对支链淀粉的合成起关键作用,ISA 3基因的表达可能对异淀粉酶活性和淀粉的合成起负调控作用。     

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。     

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。     

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.     

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.     

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.