Thymic stromal cell clone with nursing activity supports the growth and differentiation of murine CD4+8+ thymocytes in vitro

Thymic stromal cell clone, TNC-R3.1 cell, was established from spontaneous AKR/J mouse thymoma. TNC-R3.1 cell, which has the similar properties to thymic nurse cells, formed a unique complex with normal thymocyte subpopulations. Flow cytometry analysis demonstrated that CD4+8+ and CD4-8- immature thymocytes preferentially interacted with TNC-R3.1 stromal cell clone. CD4+8+ thymocytes, which interacted with TNC-R3.1 stromal cell clone, contained a higher proportion of large size and cycling T cells than did noninteracting CD4+8+ thymocytes. As is generally accepted, CD4+8+ thymocytes did not respond to any stimulation such as IL-2, anti-CD3 mAb (2C11), or IL-2 plus 2C11. However, culture of isolated CD4+8+ thymocytes on TNC-R3.1 stromal cell monolayer in the presence of suboptimal dose of IL-2 induced a significant cell growth. Moreover, the addition of 2C11 and IL-2 into this coculture system resulted in a dramatic increase of the proliferative response of thymocytes. Flow cytometry analysis showed the proliferating cells on TNC-R3.1, which originated from CD4+8+ thymocytes, were mostly TCR-alpha beta+ CD3+CD4-8+ T cells. These results provide in vitro evidence that CD4+8+ thymocytes are at an intermediate stage of T cell maturation and TNC-R3.1 stromal cell clone induces the growth and differentiation of CD4+8+ thymocytes into CD4-8+ T cells.     

Removal of selectable marker gene from fibroblast cells in transgenic cloned cattle by transient expression of Cre recombinase and subsequent effects on recloned embryo development

Introduction of selectable marker genes to transgenic animals could create an inconvenience to further research and may exaggerate public concerns regarding biological safety. The objective of the current study was to excise loxP flanked neo^R in transgenic cloned cattle by transient expression of Cre recombinase. Green fluorescent protein gene (GFP) was incorporated to monitor Cre expression; therefore, Cre-expressed cells could be selected indirectly by fluorescence-activated cell sorting (FACS). The neo^R was removed and Cre expressed transiently in GFP-positive colonies; excision of neo^R was confirmed by single-blastocyst PCR in recloned blastocysts, with neo^R-free fibroblast cells as donors. There was no difference (P > 0.05) in rates of cleavage (76.0% vs. 68.8%) or blastocyst formation (56.6% vs. 52.9%) between recloned embryos with neo^R-free or neo^R-included donors. The differential staining of recloned blastocysts were similar (P >0.05) in terms of total cell number (124 vs. 122) and the ratio of ICM (Inner Cell Mass) to the total cell number (38.1% vs. 38.2%). Furthermore, pregnancy and calving rates were not different (P > 0.05) from those of the control. In conclusion, we successfully excised neo^R from transgenic cloned cattle; the manipulation did not affect the developmental competence of recloned preimplantation embryos. This approach should benefit bioreactor and transgenic research in livestock.     

Ginsenoside Rd Attenuates Myocardial Ischemia/Reperfusion Injury via Akt/GSK-3β Signaling and Inhibition of the Mitochondria-Dependent Apoptotic Pathway

Evidence suggests Ginsenoside Rd (GSRd), a biologically active extract from the medical plant Panax Ginseng, exerts antioxidant effect, decreasing reactive oxygen species (ROS) formation. Current study determined the effect of GSRd on myocardial ischemia/reperfusion (MI/R) injury (a pathological condition where ROS production is significantly increased) and investigated the underlying mechanisms. The current study utilized an in vivo rat model of MI/R injury and an in vitro neonatal rat cardiomyocyte (NRC) model of simulated ischemia/reperfusion (SI/R) injury. Infarct size was measured by Evans blue/TTC double staining. NRC injury was determined by MTT and lactate dehydrogenase (LDH) leakage assay. ROS accumulation and apoptosis were assessed by flow cytometry. Mitochondrial membrane potential (MMP) was determined by 5, 5′, 6, 6′-tetrachloro-1, 1′, 3, 3′-tetrathylbenzimidazol carbocyanine iodide (JC-1). Cytosolic translocation of mitochondrial cytochrome c and expression of caspase-9, caspase-3, Bcl-2 family proteins, and phosphorylated Akt and GSK-3β were determined by western blot. Pretreatment with GSRd (50 mg/kg) significantly augmented rat cardiac function, as evidenced by increased left ventricular ejection fraction (LVEF) and ±dP/dt. GSRd reduced myocardial infarct size, apoptotic cell death, and blood creatine kinase/lactate dehydrogenase levels after MI/R. In NRCs, GSRd (10 µM) inhibited SI/R-induced ROS generation (P<0.01), decreased cellular apoptosis, stabilized the mitochondrial membrane potential (MMP), and attenuated cytosolic translocation of mitochondrial cytochrome c. GSRd inhibited activation of caspase-9 and caspase-3, increased the phosphorylated Akt and GSK-3β, and increased the Bcl-2/Bax ratio. Together, these data demonstrate GSRd mediated cardioprotective effect against MI/R–induced apoptosis via a mitochondrial-dependent apoptotic pathway.     

浙江西门岛海洋特别保护区大型底栖动物功能群特征及其与环境的关系

为研究浙江西门岛海洋特别保护区大型底栖动物功能群的变化规律及其与环境因子的关系,作者分别于2010年4月(春季)、11月(秋季),2011年8月(夏季)和2012年2月(冬季)进行了4个航次的大型底栖动物调查,共鉴定出大型底栖动物78种,根据其食性类型划分为浮游生物食者、植食者、肉食者、杂食者、碎屑食者5种功能群.各功能群平均密度从高到低依次为浮游生物食者＞肉食者＞植食者＞碎屑食者＞杂食者,平均生物量从高到低依次为浮游生物食者＞碎屑食者＞肉食者＞杂食者＞植食者.单因素方差分析结果表明,大型底栖动物各功能群的密度和生物量季节间均无显著性差异.典范对应分析结果表明,影响大型底栖动物功能群的主要环境因子包括温度、溶解氧、溶解态无机磷和表层沉积物的中值粒径,排序轴对功能群-环境关系的贡献率计算结果表明环境变量可以较好地解释功能群的变化情况.     

黄瓜雄花形成过程中心皮的发育

黄瓜(Cucumis sativus L.)为重要的经济作物,雌雄同株异花,是研究植物性别分化的经典材料。人们对黄瓜性别分化进行了广泛的研究。Astmon和Galun、任吉君和王艳对黄瓜性别分化的形态特征和器官发生进行了初步研究,表明黄瓜单性花分化和发育过程中经历了无性期、两性期和单性期,最终只有一种性别的性器官原基发育成有功能的性器官,从而形成单性花,而对单性花中未形成有功能器官的相反性别原基的研究报道甚少。我们对雄花发育过程进行了连续的形态学分析,并对不同时期雄花中的心皮进行了细胞计数和同工酶电泳分析,以期从性器官发育的角度探讨黄瓜性别表现的机理。     

土壤原生动物群落及其生态功能

土壤原生动物是土壤微生物区系的重要组成部分。在土壤生态系统中 ,由于微生物与微动物的生命活动及其相互作用 ,从而形成了土壤的物质循环和能量转化。土壤原生动物既参与了微生物所介导的物质转化和能量循环 ,又参与了动物对微生物的捕食作用。由于原生动物具有丰富的种类和多样性以及巨大的生物量 ,所以土壤原生动物的群落及其生态功能 ,已引起了人们的广泛关注 ,并且研究理论与方法日益深入。但我国在这方面的研究报道较少 ,本文拟从群落与生态功能方面的进展做一概述。1　土壤原生动物的群落特征土壤与淡水原生动物最早是由Ａｎｔｏｎ…     

蛋白质组学在去泛素化酶研究中的应用

泛素-蛋白酶体系统是细胞内蛋白质特异性降解的主要途径,参与并调控细胞周期、免疫应答、信号传递和DNA修复等真核生物体内几乎所有的生命活动。去泛素酶的存在使泛素化修饰成为可逆过程,保证了泛素系统及其相关生理过程的动态平衡,其表达紊乱也是诱发多种疾病的主要原因。对去泛素化酶进行系统、全面的研究是理解其作用机制并将其作为治疗药物靶点的前提。蛋白质组学技术的快速发展为系统深入研究去泛素化酶提供了条件,特别是在去泛素化酶的相互作用网络和底物特异性研究等方面发挥了独特的作用。因此,文中结合课题组研究工作,对去泛素化酶的分类及功能进行介绍并总结了蛋白质组学在去泛素化酶研究中的应用进展。