通过睾丸内注射转染外源DNA在小鼠精子的表达

为研究睾丸内注射外源DNA法生产转基因小鼠(Mus musculus)的可行性,并探讨注射DNA的最佳浓度。将环形的质粒DNA pEGFP-N1与脂质体混合制备DNA-脂质体复合物,按DNA浓度不同分为0.08μg/μl、0.12μg/μl和0.24μg/μl3组,分别注射入成年SPF级昆明小鼠睾丸内,同时设空白对照;每组处理公鼠2只,注射5d后每只与3只成年母鼠同笼,20d后在荧光显微镜下检测公鼠附睾精子,并制作睾丸石蜡切片,检测绿色荧光蛋白(GFP)的表达;PCR法检测各组后代阳性率。结果显示,3组小鼠附睾荧光精子比例分别为9.09%、47.06%和27.78%。3组小鼠的睾丸石蜡切片中均可看到不同强度的GFP表达。后代经PCR检测阳性率分别为17.26%、47.61%和22.11%。本实验证实了睾丸注射法能使外源DNA整合进入精子基因组,并能在自身和后代中得到表达,本研究中外源DNA注射浓度以0.12μg/μl效果为最佳。     

睾丸注射法制备携带山羊H-FABP基因的转基因小鼠

为探究睾丸注射法制备转基因动物的可能性,文章将携带有山羊心脏型脂肪酸结合蛋白(H-FABP)和绿色荧光蛋白标签的重组载体经脂质体包裹后随机打点注射小鼠睾丸。对实验小鼠进行睾丸切片、精子荧光检测以及精子DNA检测,证实外源基因在亲代小鼠体内成功表达。睾丸注射后小鼠与正常母鼠交配产生的F1代,以及F1代自交产生的F2代在不同水平均可检测到外源基因的成功表达,阳性率分别为4%和30.23%。研究结果说明睾丸注射是一种制备转基因动物行之有效的方法,且外源基因可以稳定遗传。该方法的完善和成熟对于动物转基因以及动物性状改良和育种具有理论和实践意义。     

睾丸内注射pEGFP-N1体内转染精子并在山羊早期胚胎成功表达

目的探讨睾丸内注射法pEGFP-N1在精细胞的整合和在早期胚胎中表达.方法选择4头本地山羊,双侧睾丸注射不同剂量质粒DNA pEGFP-N1,注射后PCR和Southern杂交检测pEGEP-N1在精子中的整合.结果pEGFP-N1整合到精子基因组中,转染效率最高发生在注射后第40天,转染阳性率最高为81%;绿色荧光蛋白在精子及其体外受精的部分胚胎中表达,胚胎阳性率最高的达66.7%.结论通过睾丸内注射pEGFP-N1能整合进入精子基因组,并能通过体外受精在山羊早期胚胎中表达;睾丸内注射法可能是一种可行、简单并利于推广的制备转基因山羊的方法.     

体内系统转基因新方法

建立了一种全新而高效的制备转基因动物新方法.无需外科手术,将含有绿色荧光蛋白的重组质粒直接多次多点反复注射到雄性ICR小鼠的睾丸内.几周后,上述雄性动物与自然发情的雌性交配,制备转基因动物.经PCR检测、DNA印迹,实验结果表明:F1代小鼠转基因阳性率为41%.经DNA印迹证明:外源基因已经整合到子代转基因动物的基因组内并能遗传给后代.将F1代阳性鼠与正常ICR鼠交配,产生F2代转基因鼠,F2代转基因阳性率37%.上述实验结果表明,建立的体内系统转基因方法简便、高效,适用于大规模制备转基因动物,特别适用于一些大型家畜.     

小鼠睾丸注射不同转染试剂和注射方法对外源基因表达的影响

为探讨不同转染试剂(LipofectamineTM LTXPLUSTM、Lipofectamine2000和纳米化聚酰胺-胺型树枝状聚合物(PAMAM-D))和睾丸注射方法 (睾丸网注射、曲精细管注射和间质注射)对转基因小鼠生产效率的影响,将pEGFP-C1质粒分别与不同转染试剂混合后,按照不同的注射方法注入小鼠睾丸内,30 d后检测小鼠精子密度、活力、精子阳性率以及配种后仔鼠转基因阳性率。结果 3种转染试剂对小鼠繁殖性能影响由小到大依次为LipofectamineTM LTXPLUSTM、Lipofectamine 2000和PAMAM-D。转染后LipofectamineTM LTXPLUSTM、Lipofectamine 2000和PAMAM-D组精子的GFP阳性率分别为35.65%±0.69%、12.86%±0.35%和10.04%±0.20%。配种后仔鼠的PCR阳性率分别为29.17%、13.70%和5.88%。3种不同注射方法对小鼠睾丸都造成损伤,由小到大依次为睾丸网注射、曲精细管注射和睾丸间质注射,三者的阳性精子比例分别为35.13%±1.727%、15.13%±1.457%和0%,配种后仔鼠的PCR阳性率分别为33.3%、12.5%和0%。结果表明,LipofectamineTM LTXPLUSTM和睾丸网注射对小鼠睾丸的损伤最小,并能获得较高的转染效率。     

睾丸注射法制备携带猪PID1基因的转基因兔

目的研究磷酸酪氨酸互作结构域1(PID1)基因与肌内脂肪含量的关系,探究睾丸注射法在转基因动物制备中的可行性。方法将携带猪PID1基因的重组质粒pIRES2-acGFP-PID1与转染试剂共孵育后,对新西兰兔进行了睾丸打点注射试验。对繁殖的F1代个体进行了活体荧光检测、PCR和western blotting检测,以及抽样屠宰进行肌内脂肪含量等检测;将F1代阳性个体互交,繁殖了F2代兔,对其进行了阳性率检测以及肌内脂肪含量检测。结果外源PID1基因和荧光蛋白基因在后代中均成功表达,其中,F1代阳性率为35.88%,F2代阳性率为34.33%;转基因阳性兔与阴性和空白对照兔相比,PID1蛋白表达水平有所增加,肌内脂肪含量有显著提高(P0.05)。结论 PID1基因与肌内脂肪沉积密切相关,同时,进一步证明了睾丸注射法可以用于制备转基因动物,且外源基因可以稳定遗传。     

绿色荧光蛋白基因在转基因小鼠体内的表达

建立绿色荧光蛋白（GFP）转基因小鼠,继而传代建系。采用显微注射法,将GFP基因注入FVB／NJ小鼠受精卵原核内,获得子代鼠。分娩后3周剪取仔鼠尾,提取基因组DNA,应用PCR、Southern印迹技术进行整合检测。结共用雌性小鼠200只,注射受精卵1586枚,移植卵数386枚,受体鼠32只,怀孕鼠4只,子代鼠18只,有4只为阳性：取2只首建鼠的胚胎,在荧光显微镜下观察GFP表达明显,表明初步获得了转绿色荧光蛋白基因小鼠,     

体内外精原干细胞介导大群生产转基因鸡

本研究以重组的绿色荧光蛋白基因为标记,采用公鸡睾丸内转染精原干细胞（spermatogonial stem cells,SSCs）和体外转染SSCs再移植的方法,探索家禽转基因新方法．同时比较了公鸡接受不同剂量外源基因的转基因效率．结果显示：（i）接受外源基因剂量分别为50,100,150和200μg／mL时,48h后睾丸细胞显示绿色荧光的比率分别为4．0％,8．7％,10．2％和13．6％,差异显著（P〈0．05）．睾丸内注射外源基因第25天后,随着时间的增长,精子表达绿色荧光的百分率逐渐提高,到第70天后表达率达到高峰,且趋于稳定,4个剂量组分别为12．7％,12．8％,15．9％和19．1％．差异显著（P〈0．05）;（ii）第70天的睾丸冰冻切片观察,曲精细管周边均有荧光表达;（iii）F1代中,56．2％（254／452）的胚盘表达绿色荧光．活鸡血样PCR检测56．5％（13／23）为阳性,Southern blot检测证明外源基因已整合到鸡基因组;F2代中,53．2％（275／517）的胚盘表达绿色荧光．活鸡血样PCR检测52．9％（9／17）为阳性;（iv）F,代和F2代鸡心、肝、肾和肌肉等组织冰冻切片观察和PCR检测,绿色荧光阳性率在50．0％～66．7％之间;（v）体外SSCs转染外源基因后移植,可在受体公鸡睾丸中生长发育,正常产生精子．后代中,12．5％（8／64）的胚盘表达绿色荧光,活鸡血样PCR检测11．1％（2／18）为阳性．结果证明精原干细胞介导转基因是一种简单、高效、可大群体生产转基因鸡的有效途径．     

PiggyBac在转基因小鼠制备中的应用

受精卵雄原核裸DNA注射是目前制备转基因小鼠的主要技术,而转基因表达成功率低是这种技术的主要缺点。piggyBac转座子系统已被报道用于制备转基因小鼠,但这一方法是否能够提高转基因的表达成功率尚不清楚。为此,我们利用毛色基因agouti为报告基因,采用piggyBac转座子系统以C57/BL6小鼠为背景进行转基因小鼠的制备。结果表明,将piggyBac转座酶cRNA和转基因载体进行受精卵雄原核共注射后,转基因阳性率为18.4%,转基因表达率为88.89%,显著高于单独进行转基因载体DNA受精卵雄原核注射法。同时,利用agouti基因作为报告基因,可根据毛色变化直接对表达阳性的转基因小鼠进行初步筛选,提高了筛选效率。     

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。     

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.     

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.     

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.     

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.