当年生高山姬鼠最大代谢率

用开放式呼吸仪测定了当年生和往年生高山姬鼠的冷诱导和运动诱导最大代谢率。当年生高山姬鼠的冷诱导最大代谢率为:(7.25±0.25)mLO2/(g.h),运动诱导最大代谢率为(9.22±0.27)mLO2/(g.h);当年生鼠冷诱导最大代谢率雌雄间无显著差异,运动诱导最大代谢率雌雄间差异显著。当年生高山姬鼠的冷诱导最大代谢率低于往年个体,运动诱导最大代谢率高于往年生个体。结果表明:当年生高山姬鼠忍受寒冷的能力低于往年个体,可能是对横断山地区年平均气温较低的自然环境的胁迫产生的适应;而雄性运动诱导最大代谢率大于雌性,可能是为了适应避免近亲繁殖和激烈竞争而在性成熟后从出生地向外扩散。     

黑腹绒鼠的代谢产热特征及其体温调节

为探讨东洋界华中区黑腹绒鼠的代谢产热特征及体温调节,本文采用封闭式流体压力呼吸仪对其代谢率、热传导和体温等热生物学指标进行了测定.结果显示:在环境温度为5～25℃的范围内,黑腹绒鼠的体温基本维持恒定,平均体温为36.5±0.1℃;热中性区为25～30℃;基础代谢率为2.99±0.09 ml O2/(g·h);环境温度(Ta)在5～25℃范围内,代谢率(MR)与Ta呈负相关,回归方程为:MR[ ml O2/(g·h)]= 6.56-0.16 Ta(℃),在此范围内,黑腹绒鼠的热传导率C最低,平均为0.26±0.01 ml O2/(g·h·℃).黑腹绒鼠的基本热生物学特征为:较高的BMR、热传导率和体温以及较宽的热中性区.     

中缅树鼩体温、代谢率和蒸发失水日节律

为研究中缅树鼩(Tupaia belangeri)体温、代谢率和蒸发失水的日节律变化,采用植入式体温计测定了中缅树鼩24 h的体温,以及24 h中4个时间段(05:00～07:00时、11:00～13:00时、17:00～19:00时和23:00～01:00时)热中性区(30℃)的静止代谢率(RMR)、非颤抖性产热(NST)和蒸发失水(EWL)。结果显示,中缅树鼩的体温具有日节律变化,最高值和最低值分别出现在11:00时和03:00时,各为(39.45±0.26)℃和(36.34±0.24)℃;静止代谢率、非颤抖性产热和蒸发失水在4个时间段都有显著差异,表现出显著的日节律变化,代谢率在23:00～01:00时最大,O2含量为(2.58±0.04)ml/(g.h),在11:00～13:00时最小,O2含量为(2.28±0.09)ml/(g.h);非颤抖性产热在05:00～07:00时最大,O2含量为(3.08±0.14)ml/(g.h),在11:00～13:00最小,O2含量为(2.69±0.63)ml/(g.h);蒸发失水在17:00～19:00时最大,失水量为(3.60±0.31)mg/(g.h)。结果表明,体温的日节律变化主要与环境温度的日节律变化和下午出窝取食活动性增强有关;当夜晚环境温度相对较低的时候,通过增强静止代谢率和非颤抖性产热来增加产热,而白天环境温度相对较高的时候,通过增强蒸发失水散热来调节体温。     

横断山两种小型哺乳动物的蒸发失水与体温调节

在实验室条件下测定了大绒鼠和高山姬鼠在不同温度下的蒸发失水与能量代谢.结果表明:大绒鼠和高山姬鼠的热中性区分别为22.5～30℃和25～30℃;平均体温分别为36.12℃和36.17℃;大绒鼠和高山姬鼠的基础代谢率(BMR)分别为2.99±0.48 ml O2/g ·h和4.24±0.50 ml O2/g·h;大绒鼠和高山姬鼠的平均最小热传导(Cm)分别为0.26±0.038 ml O2/g·h·℃和0.32±0.034 ml O2/g·h·℃;大绒鼠和高山姬鼠的蒸发失水随着温度增高而增加,大绒鼠的蒸发失水在30 ℃达高峰值,为10.32 mg H2O/g·h,高山姬鼠在35℃达高峰值,为14.57mg H2O/g·h;大绒鼠和高山姬鼠的热散失占总产热的比率随着温度增高而增加,大绒鼠在30 ℃达到最大为34.6%,高山姬鼠在35℃达到最大为37.5%.这些结果很可能反映出横断山小型啮齿类动物的特征,即体温相对较低,代谢水平较高,热传导也较高,蒸发失水在总产热中占有重要的地位.     

大绒鼠和高山姬鼠的体温调节和产热特征

大绒鼠和高山姬鼠为横断山地区小型哺乳动物的代表。为探讨它们在该地区的生理生态适应特征,对其体温调节和产热特征进行了测定。代谢率采用封闭式流体压力呼吸计进行测定。结果表明:大绒鼠和高山姬鼠热中性区分别为25～32.5℃ 和25～30℃;平均体温分别为35.92 ±0.37℃和36.01±0.83℃,前者体温在20～27.5℃ 范围内维持恒定,后者体温在15～27.5℃范围内维持恒定;大绒鼠和高山姬鼠基础代谢率(BMR)分别为3.76±0.07 ml O₂/g.h和4.58±0.09 ml O₂/g.h;大绒鼠和高山姬鼠平均最小热传导(Cm) 分别为0.28±0.005 ml O₂/g.h ℃ 和0.32±0.009 ml O₂/g.h℃;热中性区内,大绒鼠和高山姬鼠的F值(RMR/ Kleiber 期望RMR)/(C/Bradley 期望C) 分别为0.88±0.05 和1.10±0.05。它们的产热特征和体温调节模式很可能反映了横断山地区小型啮齿动物的特征,即体温较低、维持体温稳定的环境温度范围较窄、BMR水平较高、热传导率高。高山姬鼠的体温、C值和BMR 都比大绒鼠的高,并且高山姬鼠维持体温稳定的环境温度范围比大绒鼠的宽,它们产热特征和体温调节模式的这些差异与其分类地位、生活习性和栖息生境等因素密切相关。     

高原鼠兔和根田鼠的最大代谢率

采用He-O2混合诱导方法测定了高原鼠兔（Ochotona curzoniae）和根田鼠（Microtus oeconomus）的最大代谢率（MMR）。高原鼠兔的最大代谢率在夏季和冬季分别为5．93（体重为118g）和6．33（体重为115．8g）mlO2/g.h,而根田鼠在夏季和冬季分别为12．70（体重为27．8g）和18．29（体重为17．5g）mlO2/g.h,并且根田鼠的最大代谢率的变化幅度大于高原鼠兔,存在种间差异。MMR季节变化的不显著性来源于动物环境温度在夏季较低,而在冬季为越冬亦采用行为调节等其它机制。栖于青藏高原的高原鼠兔和根田鼠同时受到低温和低氧的腔迫,而两者对最大代谢率作用相反,导致两种动物的最大代谢率与各自期望值相比差异不大。     

大绒鼠体温调节和产热特征

大绒鼠为横断山脉地区小型哺乳动物的典型代表; 其体温仅能在15～30℃范围内维持稳定; 在热中性区内, 最低静止代谢率为2.71±0.13 ml O₂/g.h, 为其体重预期值的203.2±10.13%; F-值 {(RMR/Me)/(Cm/ C'} 为0.99±0.05; 在 25℃的NSTmax为 5.18±0.19)ml O₂/g.h; BAT 重量为0.33±0.05 g, 为体重的0.84%, BAT细胞线粒体的产热活性较高;肝脏也具有较强的产热活性。大绒鼠的产热特征和体温调节模式很可能反映了横断山地区小型啮齿动物的特征。     

长期强迫运动对大绒鼠体重、能量代谢和血清瘦素的影响

动物稳定体重的维持需要能量摄入和消耗之间的平衡。运动是影响动物能量平衡的重要因素之一。为了解运动对大绒鼠(Eothenomys miletus)的生理学效应,在室内条件下,测定了强迫运动训练(运用小鼠封闭跑台)8周后大绒鼠的体重、代谢率、摄入能、血清瘦素和身体组成的变化。结果显示,强迫运动训练8周对大绒鼠的体重无显著影响;大绒鼠的代谢率和摄入能均显著增加,训练8周后静止代谢率较对照组增加了29.9%,运动最大代谢率较对照组增加了10.7%;强迫运动训练8周组的身体脂肪重量比对照组降低了28.9%,血清瘦素水平比对照组下降了27.4%,对照组的瘦素与体脂含量具有明显的相关性,但运动组则不具有相关性;运动组的肝重量和消化道重量较对照组均显著增加;而体水重量则显著降低。这些结果表明,在强迫运动训练期间大绒鼠主要通过动员储存的脂肪、增加代谢率和食物摄入的方式来维持自身的体重及能量平衡。瘦素在长期强迫运动过程中对身体脂肪含量的变化具有调节作用。     

季节性模拟对大绒鼠能量代谢的影响

本实验主要阐明大绒鼠Eothenomys miletus在季节性模拟过程中体质量调节和能量代谢的变化。实验组大绒鼠在模拟夏季环境中(25℃,16L∶8D)驯化14 d后转入模拟冬季环境中(5℃,8L∶16D)驯化8 d,实验中每隔1 d测定大绒鼠的体质量、摄食量,每隔7 d测定其静止代谢率,实验结束后测定体脂含量和血清瘦素浓度。结果表明:季节性模拟条件下大绒鼠的体质量变化差异具有统计学意义(F=1.911,P0.05),22 d后实验组体质量比对照组下降12.54%;摄食量变化差异具有高度统计学意义(F=8.850,P0.01),22 d后实验组摄食量比对照组显著增加58.23%;静止代谢率变化差异具有高度统计学意义(F=9.969,P0.01),22 d后实验组比对照组显著增加82.22%;体脂含量和血清瘦素浓度呈显著正相关。以上实验结果表明:大绒鼠在模拟夏季转冬季的过程中主要通过降低体质量、增加摄食量和产热等来适应冷环境的胁迫。此外,瘦素有可能参与了大绒鼠在该环境下的体质量调节。     

笼养普通朱雀适应北方冬季气候的 体温调节特征

内温动物的能量代谢和体温调节表现出普遍的季节性适应,这对于动物的能量分配、存活和繁殖等具有积极意义。本研究中,利用陆生动物呼吸代谢测量系统,测定了在北方适应了3年(2018至2020年)的普通朱雀(Carpodacus erythrinus)冬季代谢产热特征,以期理解该物种对北方冬季气候的响应。结果发现,普通朱雀冬季基础代谢率(以单位时间耗氧量表示)为(6.5±0.3)ml/(g·h);热中性区为20～35℃,环境温度低于下临界温度时,代谢率随环境温度降低显著升高,环境温度高于上临界温度时,代谢率随环境温度升高显著增加。体温在环境温度为10～25℃时,保持相对稳定,为(42.9±0.15)℃;环境温度为5℃时体温降低,高于30℃时,体温升高。最小热传导(0.25±0.02)ml/(g·h·℃),热传导随环境温度上升显著增加。与已有关于普通朱雀的研究报道相比较,本结果表明,普通朱雀在冬季代谢产热增加,以维持较高体温;热中性区变宽,下临界温度下调,以节省体温调节的能量支出;体温维持较高水平以抵抗寒冷,当气温过低时,适当降低体温,以减少直接能量消耗。     

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.     

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.