MTOR signaling is essential for the development of thymic epithelial cells and the induction of central immune tolerance

Thymic epithelial cells (TECs) are critical for the establishment and maintenance of appropriate microenvironment for the positive and negative selection of thymocytes and the induction of central immune tolerance. Yet, little about the molecular regulatory network on TEC development and function is understood. Here, we demonstrate that MTOR (mechanistic target of rapamycin [serine/threonine kinase]) is essential for proper development and functional maturation of TECs. Pharmacological inhibition of MTOR activity by rapamycin (RPM) causes severe thymic atrophy and reduction of TECs. TEC-specific deletion of Mtor causes the severe reduction of mTECs, the blockage of thymocyte differentiation and output, the reduced generation of thymic regulatory T (Treg) cells and the impaired expression of tissue-restricted antigens (TRAs) including Fabp2, Ins1, Tff3 and Chrna1 molecules. Importantly, specific deletion of Mtor in TECs causes autoimmune diseases characterized by enhanced tissue immune cell infiltration and the presence of autoreactive antibodies. Mechanistically, Mtor deletion causes overdegradation of CTNNB1/Beta-Catenin due to excessive autophagy and the attenuation of WNT (wingless-type MMTV integration site family) signaling in TECs. Selective inhibition of autophagy significantly rescued the poor mTEC development caused by Mtor deficiency. Altogether, MTOR is essential for TEC development and maturation by regulating proliferation and WNT signaling activity through autophagy. The present study also implies that long-term usage of RPM might increase the risk of autoimmunity by impairing TEC maturation and function.     

两种骨丢失动物模型骨质,甲状旁腺激素和降钙素的变化比较

本文观察了模拟失重１４天、２１天大鼠和卵巢切除（ＯＶＸ）３０天、６０天大鼠第６胸椎（Ｔ６）、第３腰椎（Ｌ３）和股骨干骨量、骨生物力学特性,血ＰＴＨ和ＣＴ变化特点。实验结果显示,悬吊１４天大鼠Ｔ６和Ｌ３矿盐密度显著增加,２１天Ｔ６矿盐密度显著增加,但Ｌ３矿盐密度显著降低。ＯＶＸ大鼠Ｔ６矿盐密度无变化,但Ｌ３矿盐密度显著降低。悬吊１４天、２１天大鼠股骨干近侧１／３段矿盐含量显著降低,ＯＶＸ６０天大鼠股骨干近侧１／３段矿盐含量显著降低。悬吊大鼠骨力学特性降低较ＯＶＸ大鼠严重。悬吊大鼠血ＰＴＨ无变化,但ＣＴ显著增加,ＯＶＸ大鼠ＰＴＨ、ＣＴ显著降低。实验结果提示,模拟失重大鼠有骨矿盐再分布现象发生,ＯＶＸ大鼠无此现象。悬吊模拟失重大鼠骨质量的降低较ＯＶＸ大鼠严重。在两个动物模型中,皮质骨和松质骨均受影响。     

Gastrodin Attenuates Cognitive Deficits Induced by 3,3′-Iminodipropionitrile

3,3′-Iminodipropionitrile (IDPN), one of the nitrile derivatives, can induce persistent neurotoxicity, and therefore cause dyskinesia and cognitive impairments. Gastrodin, a main bioactive ingredient of Gastrodia elata Blume, is shown to greatly improve cognitive function. The aim of this study was to further determine whether administration of gastrodin can ameliorate IDPN-induced cognitive deficits in the Morris water maze (MWM) and novel object recognition (NOR) task, and to explore the underlying mechanisms. Results showed that exposure to IDPN (100 mg/kg/day, for 8 days) significantly impaired spatial and object recognition memory and that repeated treatment with gastrodin (150 mg/kg/day, for 6 weeks) could effectively alleviate the IDPN-induced cognitive impairments as indicated by increased spatial memory and discrimination ratio in the MWM and NOR tests. Gastrodin treatment also reverted IDPN-induced decreases of γ-aminobutyric acid (GABA) levels and increases of a2 GABA_A receptor protein expression in the prefrontal cortex and hippocampus of IDPN-treated rats. These results suggest that gastrodin treatment may provide a novel pharmacological strategy for IDPN-induced cognitive deficits, which was mediated, at least in part, by normalizing the GABAergic system.

     

基于地形的牲畜空间利用特征及干扰评价——以王朗国家级自然保护区为例

地形是栖息地的基本要素, 从地形评价动物的空间利用特征能够掌握动物的分布规律并进行预测。为掌握保护区内牲畜的空间利用特征, 并评价它们对主要保护动物的潜在影响, 我们于2018年5-11月调查了王朗国家级自然保护区内牛和马的分布, 并结合红外相机监测结果及历史监测数据进行了分析和评价。结果表明: (1)虽然两种牲畜均偏好低海拔、低坡度、光照良好(半阳坡、阳坡)、距水源近的栖息地, 但它们在地形利用上存在显著差异; (2)牲畜活动最频繁的三条沟分别是竹根岔右一支沟、竹根岔正沟和大窝凼洋洞沟, 且呈现不同的干扰特征; (3)基于监测数据, 羚牛(Budorcas taxicolor tibetana)可能是保护区内最易受牛马活动威胁的保护动物。红外相机监测结果显示, 羚牛沿海拔分布现状可能是回避牲畜密集区域的结果。基于本研究, 我们建议: (1)保护区重点关注竹根岔(右一支沟、正沟、白沙沟)、大窝凼(洋洞沟、外侧坡)两个核心区的牲畜活动情况, 并尽快针对放牧采取措施。例如, 持续监测重点干扰区域牲畜的种群数量和空间分布趋势。(2)严格限制牲畜继续向高海拔栖息地入侵。(3)管控放牧投盐等干扰的发生频率。(4)加强执法力度, 防止牲畜对保护区带来的干扰持续和扩大, 威胁物种安全。     

A new sub-sampling method for analysis of air samples collected with the Andersen single-stage sampler

A protocol for bioaerosol collection was developed that provides not only accurate predictions of fungal concentration, but also improves species recovery. Random transfer of a subset of 50 of the 400 impaction points from Andersen single-stage bioaerosol sampling plates results in subcultures that are accurate predictors of fungal concentration (CFU/m³), when compared to duplicate untouched Andersen plates. A linear regression model was developed to estimate CFU/m³ from the colonies counted on the Random-50 plates. The random transfer to five plates (“Random-50” plates), allows large numbers of fungi to be recovered and identified, including slow-growing fungi that otherwise would be masked by fast-growing fungi.     

High-level expression and purification of soluble recombinant FGF21 protein by SUMO fusion in <Emphasis Type="Italic">Escherichia coli</Emphasis>

Background  

Fibroblast growth factor 21 (FGF21) is a promising drug candidate to combat metabolic diseases. However, high-level expression and purification of recombinant FGF21 (rFGF21) in Escherichia coli (E. coli) is difficult because rFGF21 forms inclusion bodies in the bacteria making it difficult to purify and obtain high concentrations of bioactive rFGF21. To overcome this problem, we fused the FGF21 with SUMO (Small ubiquitin-related modifier) by polymerase chain reaction (PCR), and expressed the fused gene in E. coli BL21(DE3).     

Plasma pharmacokinetics and tissue distribution study of physalin D in rats by ultra-pressure liquid chromatography with tandem mass spectrometry

Physalin D is an important constituent of some traditional Chinese medicines, and has several known bioactivities. An UPLC-MS/MS method for the determination of physalin D in rat plasma and tissues was developed and the pharmacokinetic and tissue distribution characteristics of physalin D after intravenous administrations were investigated. The bio-samples were prepared by a simple protein precipitation, and the separation of physalin D was achieved on a UPLC HSS T3 column with a mobile phase consisting of methanol/acetonitrile (70:30, v/v) and water (containing 0.1% formic acid and 10 mM ammonium acetate) at a flow rate of 0.3 mL/min. The MS/MS detection was carried out by monitoring the fragmentation of m/z 544.9→508.8 for physalin D and m/z 286.7→152.8 for luteolin (internal standard; IS) on a triple-quadrupole mass spectrometer. The total run time was only 3.6 min. The analyte showed good linearity over a wide concentration range (R(2)>0.995) and its lower limit of quantification was 2 ng/mL. The pharmacokinetic study found that physalin D was distributed and eliminated rapidly in rats (t(1/2)<10 min). Tissue distribution showed the highest level was observed in kidney, then in liver, but no physalin D was detected in brain, which indicated that kidney was the major distribution tissue for physalin D in rats and that physalin D does not cross the blood-brain barrier.     

四川王朗国家级自然保护区血雉的日活动节律

血雉Ithaginis cruentus是分布在青藏高原东部至喜马拉雅山脉的珍稀濒危雉类物种。本研究使用红外相机调查技术,于2014—2018年在四川王朗国家级自然保护区168个标准公里网格内布设调查位点283个,其中249个有效位点上总有效工作量为26 123相机日,共拍摄到血雉照片与视频合计8 907份(占鸡形目Galliformes总数的71.46%),独立探测922次(占鸡形目总数的70.11%),相对多度指数35.29。基于核密度函数绘制了血雉的日活动节律曲线,结果显示,血雉为严格的日行型动物,所有记录均发生在05∶50—19∶50;日活动曲线整体呈现单峰模式:活动强度在日出后快速增加,在09∶00—11∶00达到最高,之后强度逐渐降低,在18∶00后快速下降。在不同季节,血雉的日活动节律模式存在差异,繁殖期与非繁殖期的日活动节律模式差别较为明显。本研究基于可靠的调查手段和充足的数据量,分析了血雉的日活动模式,表明红外相机技术是动物行为研究的有效工具,为血雉及其他森林雉类行为生态的深入研究提供了基础资料与信息。     

王朗国家级自然保护区滑坡体兰科植物分布格局及其保护策略

滑坡体是大熊猫国家公园岷山片区中广泛存在的一种生境, 但其在生物多样性研究和保护中的作用却没有得到足够的重视。王朗国家级自然保护区的滑坡体具有丰富的兰科植物资源, 其中白沙沟滑坡体最为丰富。本文以白沙沟滑坡体为例, 探究岷山地区滑坡体生境中兰科植物的空间分布格局, 拟为王朗国家级自然保护区及周边区域的兰科植物保护提供指导。本研究设置4条样带共186个样方, 利用除趋势对应分析(DCA)和双向指示种分析(TWINSPAN)研究滑坡体兰科植物的空间分布格局, 同时对兰科植物做了种间关联和相关性分析。结果表明, 白沙沟滑坡体的草本群落受环境因素的影响, 物种间竞争较弱, 处于自然演替的初始阶段。郁闭度和水流冲刷对滑坡体兰科植物的分布具有重要影响。受郁闭度和水流干扰因素的影响, 滑坡体可分成滑坡体-林缘生境(类型1)、滑坡体生境(类型2)和高郁闭度滑坡体生境(类型3) 3种类型。兰科植物在类型1和类型3两种生境中产生了适应性分化。建议在一些兰科物种集中分布的区域设立保护点并进行监测。此外还应对其他不同时间、不同土壤基质形成的滑坡体进行详细的调查, 摸清王朗国家级自然保护区甚至岷山地区兰科植物分布的整体情况。     

Assessment of roles for calreticulin in the cross-presentation of soluble and bead-associated antigens

Antigen cross-presentation involves the uptake and processing of exogenously derived antigens and their assembly with major histocompatibility complex (MHC) class I molecules. Antigen presenting cells (APC) load peptides derived from the exogenous antigens onto MHC class I molecules for presentation to CD8 T cells. Calreticulin has been suggested to mediate and enhance antigen cross-presentation of soluble and cell-derived antigens. In this study, we examined roles for calreticulin in cross-presentation of ovalbumin using a number of models. Our findings indicate that calreticulin does not enhance in vitro cross-presentation of an ovalbumin-derived peptide, or of fused or bead-associated ovalbumin. Additionally, in vivo, calreticulin fusion or co-conjugation does not enhance the efficiency of CD8 T cell activation by soluble or bead-associated ovalbumin either in wild type mice or in mice lacking Toll-like receptor 4 (TLR4). Furthermore, we detect no significant differences in cross-presentation efficiencies of glycosylated vs. non-glycosylated forms of ovalbumin. Together, these results point to the redundancies in pathways for uptake of soluble and bead-associated antigens.