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。     

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。     

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.     

节肢动物内共生细菌研究进展

节肢动物门是动物界最大的门,占整个动物种数的80%,全世界约有120万现存种。节肢动物在生长发育过程中会感染多种微生物,这些微生物会与其形成协同进化和互利共生的关系。内共生细菌是一类广泛分布于节肢动物体内的共生微生物,能够进行垂直传播和水平传播,对宿主的生长发育、生殖代谢、适应性、免疫功能和进化等诸多方面均具有重要的作用。目前,随着现代分子生物学理论和技术的发展,节肢动物内共生细菌相关研究主要集中在对其宿主的生殖调控功能、与其宿主、宿主寄主植物以及其宿主体内微生物和宿主天敌间互作关系等方面。因此,利用内共生细菌对昆虫种群动态的生殖调控功能,阻断热带蚊虫带来的疾病或植物病害的传播并对宿主昆虫进行种群压制或种群替换,可达到防控害虫的目的。本文从节肢动物内共生细菌的传播方式、对其宿主生物学效应以及内共生细菌与其宿主、宿主寄主植物、宿主天敌和宿主体内微生物互作关系等多方面进行概述,并对内共生细菌今后研究方向进行展望,以期为生物进化、物种形成和种群压制提供参考。     

体内生物膜研究进展

生物膜是指由黏附于生命体或非生命体表面的微生物和其胞外聚合物所构成的复杂、多维的空间结构,在自然界中普遍存在。微生物在人类体内许多部位均可形成生物膜结构,如肺、心脏瓣膜、泌尿生殖道、肝胆系统、耳、鼻、皮肤等。越来越多的感染性疾病患者或动物模型体内均可检测出生物膜,如囊性纤维化肺炎、慢性中耳炎、细菌性心内膜炎、皮肤外伤后慢性感染、慢性鼻窦炎等。生物膜的形成与感染性疾病的关系及其在疾病的发生、发展、转归过程中的作用成为近年来研究的热点。目前体内生物膜检测技术主要有扫描电镜、激光共聚焦显微镜、荧光原位杂交技术等。就临床常见感染性疾病与生物膜的关系及体内生物膜检测方法展开综述。     

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.     

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.     

Fibromodulin gene is expressed in human epidermal keratinocytes in culture and in human epidermis in vivo

Fibromodulin is a small leucine-rich proteoglycan that has a central role in the maintenance of collagen fibrils structure, and in regulation of TGF-β biological activity. Although, it is mainly found in cartilage and tendon, little is known regarding the expression of the fibromodulin gene in other cell types. By RT-PCR, real time PCR and immunohistochemistry, we describe the expression of the fibromodulin gene and the presence of the protein in human epidermal keratinocytes (HEK), both in culture and in normal human epidermis. Our results show, for the first time, that fibromodulin gene is constantly expressed in HEK during culture time. Immunostaining showed that fibromodulin is located intracytoplasmically in basal and stratified keratinocytes of the growing colonies, confluent cultures, and epidermis in vivo. The expression and intracellular localization of fibromodulin in HEK is a new finding and opens new possible biological roles for the SLRP family.     

Triglyceride Uptake in Muscles in Rats

Exogenous lipid is assimilated with different priorities in adipose tissue regions and varies in the fasting and fed conditions. The quantitative role of uptake of lipid in muscle has not been evaluated. In order to examine the uptake in other than adipose tissues, U¹⁴C-oleic acid in sesame oil was administered orally to conscious rats, and lipid label measured after different times in serum, heart, liver, mesenteric, retroperitoneal, inguinal and epididymal fat pads, as well as in red and white parts of gastrocnemius, extensor digitorum longus and soleus muscles. Lipid uptake in total adipose tissue was calculated from dissected adipose tissues plus lipids extracted from the eviscerated, skinned carcass. Lipid uptake in total muscle tissue was estimated from label in dissected muscles plus that in the carcass, assuming similar intracellular lipid contents and radioactivity as that averaged from dissected muscles. Lipid uptake in the liver was calculated from directly extracted lipid. Four hours after lipid administration to fed rats lipid radioactivity in heart and serum was minimal and had essentially disappeared at 8 hours. Liver label declined rapidly from peak values at or before 4 hours. Adipose tissue radioactivity increased gradually up to 16 hours and then decreased. Label in muscles was highest at 4 hours in the red gastrocnemius, and then decreased, while the other muscles showed a constant radioactivity over the observation period (24 hours). Radioactivity expressed per unit muscle mass seemed to be proportional to the oxidative capacity of muscles. In comparisons between fed and fasted rats at 16 hours, when adipose tissue label peaked, liver, individual muscles and carcass did not show any significant differences while adipose tissue label was fivefold higher in fed than fasted rats. The distribution of total measured lipid radioactivity between total adipose tissue, total muscle tissue and liver in fed rats at this time-point was 76. 8, 14. 4 and 8. 8% respectively, and in the fasted state 26. 4, 51. 6 and 22. 0%. These estimations suggest that lipid uptake in the fed state is dominated by adipose tissue, while in the fasted state the lipid uptake is higher in muscles than adipose tissues. It was concluded that uptake of absorbed, exogenous triglyceride in muscle is of significance, particularly in the fasted state. This lipid has a half life of several days. It is suggested that this lipid is oxidized in situ, contributing with a hidden fraction to lipid energy needs, or partially transferred to adipose tissue. Lipid uptake in muscle probably constitutes a significant fraction of assimilated exogenous lipid, particularly in the fasting state.     

茧蜂滞育的研究进展

滞育现象在多种茧蜂类天敌昆虫中存在, 通过调控茧蜂滞育, 可达到延长产品货架期、延长防控作用时间、提高产品的抗逆性和繁殖力的目标, 对茧蜂的扩繁和应用具有重要意义。本文通过总结1910年以来的2 545篇国内外滞育文献, 统计得出有明确滞育诱导或滞育解除报道的茧蜂有37种, 分属7亚科16属, 其中对滞育特征有详细描述的有23种。茧蜂大多以预蛹进入滞育, 其次为幼虫滞育, 少数为成虫滞育, 其滞育敏感阶段因种不同而异。滞育持续期相对较长, 大多可维持数月, 最长的可达14个月。光周期、温度和寄主是影响茧蜂滞育的主要因子, 湿度、亲代和寄主植物也可在一定程度上影响滞育进程。目前, 茧蜂滞育的研究仅限于生物学观察阶段, 对茧蜂滞育的生理学特征、激素调控和分子调控等尚未有研究报道, 有许多问题有待进一步探讨。     

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.     

2021年中国植物科学重要研究进展

2021年中国植物科学家在国际综合性学术期刊及植物科学主流期刊发表的论文数量相比2020年显著增加, 在雌雄细胞识别与受精、干细胞命运决定、菌根共生、光合膜蛋白复合体、氮磷养分利用、先天免疫、作物从头驯化与基因组设计等方面取得了重要研究进展,“异源四倍体野生稻快速从头驯化”入选2021年度“中国生命科学十大进展”。该文总结了2021年度我国植物科学研究取得的成绩, 简要介绍了30项重要进展, 以帮助读者了解我国植物科学的发展态势, 思考如何更好地将植物科学研究与国家重大需求有效衔接。     

Review in vitro-induced flowering in bamboos

Summary The majority of bamboos (Graminae) are arborescent and perennial. The erect stems (culms) of woody bamboos are useful for a wide variety of purposes. Most bamboos flower only once at the end of very long vegetative growth phases and die afterwards. Flowering in bamboos is thought to be under genetic control, occurring somewhat like an alarm clock, going off at a preset time. The nature of this genetic clock and any interaction between the ‘internal clock’ and the environment are not yet known. Because of this ‘peculiar’ flowering behavior, bamboo seeds are available only at very long intervals. Obtaining concurrent flowering in two or more species (or varieties) in space and time is difficult, making perennial seed propagation and genetic improvement by breeding nearly impossible. Besides, this peculiar flowering behavior of bamboos is also believed to have brought the giant pandas to the verge of extinction. One of the spectacular developments in the area of bamboo genetic improvement has been the precocious in vitro induction of flowering. By this method it has been possible to rapidly accelerate the reproductive development (within 3–6 mo. versus 30–60 yr in nature). This has opened the possibility of perennial seed propagation and hybridization. In vitro induction of flowering can be obtained by diverse methods which show some similarities and differences. Induction of flowering is possible in cultures derived from both juvenile and mature explants. The proportion of seedlings induced to flower is possibly influenced by genotypic variation, though the role of methods used cannot be ruled out. A cytokinin or a shift in the auxin-cytokinin equilibrium is believed to bring about in vitro induction of flowering. The pH of the media also has an influence. Induction of flowering and rhizogenesis is considered to be an antagonistic phenomenon in vitro. A comparison between in vitro and in vivo flowering in Bambusa arundinacea has shown that though smaller, in vitro-induced florets are comparable to normal florets. There is reduced pollen fertility and some impairment in pollen wall development. Biochemical studies on the in vitro-induced flowering in bamboos have shown (1) selective expression of esterase and peroxidase isozymes during transition of nonembryogenic calluses to embryogenic calluses, somatic embryo development, germination and subsequent flowering of somatic embryo derived shoots, and (2) minimal peroxidase activity before rhizogenesis and induction of flowering in vitro. There are reports of published and comparable methods having failed to induce flowering in vitro.     

2016年中国植物科学若干领域重要研究进展

2016年中国植物科学持续稳步发展, 表现在中国植物科学家在国际主流高影响力学术期刊发表文章的数量稳中有升, 中国植物科学领域的期刊逆风出行, 进入研究性期刊世界前三甲行列。中国科学家在植物学诸多领域取得了丰硕的成果。水稻(Oryza sativa)产量性状杂种优势的分子遗传机制解析入选2016年中国科学十大进展; 植物受精过程中雌雄配子体信号识别机制的研究和独脚金内酯的受体感知机制入选2016年生命科学十大进展。我国植物科学, 特别是以水稻为代表的作物研究在国际学术界已占有一席之地。例如, 在水稻组学(如基因组和转录组等)资源和技术平台的建立、重测序的开发及功能基因的克隆和调控网络的解析方面取得了系列重要成果(如揭示了独脚金内酯信号转导的“去抑制化激活”机制、从分子水平上阐释了水稻籼粳杂种不育和广亲和性基因S5的作用机理及发现了控制水稻耐冷的基因组位点), 已经引领世界水稻乃至作物科学研究。该文对2016年中国本土植物科学若干领域取得的重要研究进展进行了概括性评述, 旨在全面追踪当前中国植物科学领域的发展前沿和研究热点, 与读者共享我国科学家所取得的杰出成就。     

昆虫microRNA的研究进展

MicroRNA (miRNA)是20世纪90年代发现的一类由内源基因编码的长度约21~24 nt的非编码单链RNA分子, 广泛存在于真核生物中, 对基因的转录后调控起着非常重要的作用。本文简要介绍了miRNA的产生与调控机制, 同时从昆虫miRNA的发现鉴定、 靶基因预测与功能验证, 昆虫miRNA的序列特征与进化, 果蝇和非果蝇类昆虫miRNA生物学功能以及供昆虫miRNA研究的网络平台等方面对昆虫miRNA的最新进展进行了综述, 旨在为进一步研究昆虫miRNA提供借鉴和参考。对昆虫miRNA的研究表明其参与调控细胞分化、 增殖及凋亡、 胚胎发育、 器官发生、 形态构建、 生理代谢、 环境协调、 行为认知、 免疫防御等几乎所有的生物过程。因此, 深入研究其生物功能、 调控网络和开发应用等可能成为今后一段时间昆虫miRNA研究的重要内容。