重力矢量对骨细胞自噬影响的初探

自噬是细胞降解自身成分并重新利用具有多种生理功能的过程,许多原因会导致细胞自噬。模拟微重力会引起细胞自噬增强,但对单一重力矢量对自噬作用的影响研究较少。本研究选择力学敏感骨细胞MLO-Y4,应用激光共聚焦显微镜和透射电镜观察细胞自噬,通过改变细胞培养基底取向方法,比较重力矢量与饥饿对骨细胞自噬作用的影响。结果表明,饥饿可以诱导正置与倒置组细胞发生明显自噬,重力矢量或者说单纯改变培养基底取向并不能诱导MLO-Y4细胞自噬的发生。     

自噬在PDT治疗中的作用及其机制研究进展

自噬是真核生物进化过程中高度保守的分解代谢和循环再利用的过程,在维持细胞状态、内环境稳态,尤其是在细胞营养不足、氧化损伤等不利环境时起着重要作用.近来研究发现自噬参与了光动力疗法的作用过程,其机制较为复杂,而且不同程度的自噬对光动力疗法杀伤效应的影响截然不同.光动力疗法是利用特定波长的光照激活光敏剂分子,通过能量转换促...     

自噬小体膜来源的形态学分析

目的:从形态学角度探寻自噬小体形成过程中的膜来源及自噬小体的超微结构特征.方法:应用透射电镜技术整理分析本中心收到的用于自噬研究的细胞标本,对自噬发生不同阶段及疑似自噬小体结构的图片进行分析.结果:在细胞内发现众多自噬小体结构,内质网、线粒体、细胞核和高尔基体均可形成类似自噬小体结构.结论:细胞内多种膜结构可能都是自噬小体的膜来源.     

纳米金棒诱导A549细胞产生自噬的机制研究

纳米金棒(AuNRs)具有众多独特的属性,已广泛运用于生物医学领域,但其是否具有潜在的生物危害尚有争议.作者运用了激光扫描共聚焦显微镜技术、western blotting技术和其他分子生物学方法从细胞氧化应激的角度探讨了AuNRs诱导A549细胞产生自噬的分子机制.研究结果表明,4μg·mL-1的AuNRs处理6 h能够诱导A549细胞自噬标志蛋白LC3-Ⅱ表达增加,LC3蛋白从细胞核转移至细胞质并形成自噬小泡.进一步研究发现,AuNRs能够降低A549细胞线粒体膜电位、ATP含量、UCP2蛋白表达水平以及细胞抗氧化能力并导致活性氧蓄积,后者可能最终引起细胞产生自噬.而10 mmol·L-1抗氧化剂NAC能够逆转上述线粒体及细胞功能的改变,并抑制自噬的发生.这一研究为深入认识其生物危害及可能机制提供了有力的实验证据.     

eATP在植物生长发育及逆境胁迫中的作用

5'-三磷酸腺苷(ATP)是生物体各种生命活动所需能量的直接来源.研究表明,ATP在植物细胞线粒体、叶绿体等细胞器中合成后,可以被转运到胞外.胞外ATP(extracellular ATP,eATP)作为一种信号分子,在植物生长发育、逆境胁迫等多种生理过程中发挥重要功能.2014年,植物细胞中发现了第一个ATP受体,为阐明植物细胞eATP信号传导过程奠定了基础.本文中,作者将对植物生长发育及胁迫响应过程中产生的eATP及其功能进行总结,对eATP的发现、释放、识别、调控与信号传导、检测方法等进行论述,并对eATP在植物中的研究提出展望.     

内分泌细胞溶酶体的超微结构研究

用电镜细胞化学方法研究内分泌细胞溶酶体的结构与功能。研究结果表明，所有内分泌细胞都存在丰富的溶酶体，分泌自噬作用普通存在于分泌肽类激素的细胞中，自体吞噬活动跃是分泌类固醇素细胞的重要特点。溶酶体通过分泌自噬和自体吞噬分别在两类内分泌细胞中参与激素分泌的调节。     

人miR-34a靶基因的生物信息学分析及载体构建

目的对人miR-34a(hsa-miR-34a)下游靶基因进行预测,并构建含自噬相关基因靶结合序列的GFP报告基因载体。方法使用TargetScan Release 5.1和RNA22软件分析hsa-miR-34a可能的靶基因,并利用Gominer软件对靶基因功能进行分析。根据预测结果,合成含自噬相关基因hsa-miR-34a靶序列的寡核苷酸,以pEGFPC2为载体构建系列质粒,并检测各载体的真核表达情况。结果预测结果显示hsa-miR-34a共有2904个下游靶基因,功能涵盖生物过程、细胞组分、分子功能三大类,其中与自噬作用直接相关的靶基因有beclin 1和sestrin 2。构建含beclin 1和sestrin 2作用位点的GFP载体共5个,质粒转染Hela细胞后在荧光显微镜下可见绿色荧光。结论成功构建hsa-miR-34a下游自噬相关基因靶位点序列GFP报告基因载体,为进一步研究hsa-miR-34a对自噬的调控作用奠定基础。     

植物细胞分离的扫描电镜制样技术

植物细胞分离制样技术,原是应用于光学显微镜的细胞学的研究,我们将该技术中的固定、氧化、水解和分离程序与扫描电镜植物组织块常规制样方法中的脱水、临界点干燥程序相结合,形成了一种扫描电镜植物细胞分离制样方法,该方法的应用不仅使分离细胞的研究由光镜扩展至扫描电镜而且与扫描电镜植物组织块的常规方法等在细胞形态学研究方面可从互为对照和补充。     

显微镜在植物细胞程序性死亡中的应用——从个体到群体

显微镜是生命科学研究中不可缺少的手段和工具。不论是电镜还是新兴起的激光共聚焦等显微技术的应用，都对生命科学的研究和发展起到了相当大的促进作用。突出的例子是动物细胞程序性死亡（或称细胞凋亡）的概念首先是在形态学详细研究的基础上提出来的。和动物细胞类似，植物细胞程序性死亡（PCD：programmed cell death）发生在生长发育的各个阶段，从受精的胚珠到植物的老化以及在其生长过程中对各种病原微生物的抵抗，PCD在维持内环境，自我平衡以及抵抗或防御性反应中起着至关重要的作用。随着各种仪器和技术手段的更新和发展，用细胞生物学手段观察细胞死亡过程及其信号传导途径成为可能。     

原子力显微术应用于单细胞水平肿瘤研究的进展

肿瘤现已严重威胁人类的生命健康.过去十年间在细胞生物力学方面的研究进展表明肿瘤的发生发展过程中总伴随着细胞表面超微形貌和机械特性的变化,为肿瘤研究带来了新的认识,有助于发展新型免标记临床疾病诊断技术.原子力显微镜(AFM)以其纳米级空间分辨率,溶液环境下对活体细胞、组织等生物样本进行成像、测量的独特优势,成为肿瘤细胞生物力学研究的重要工具.本文综述了AFM在肿瘤细胞机械特性测量,超微形貌成像,及分子识别方面的研究进展,对其面临的困难和挑战进行了讨论,并对其应用前景进行了展望.     

The Systems Reliability Service and Its Generic Techniques

The formation of the Systems Reliability Service (SRS) is discussed against a background of historical reliability development. This background extends to nearly twenty years ago when various methods of carrying out safety assessments of nuclear plant and systems were being formulated. The early deterministic methods relying to a great extent on subjective judgement have been developed into more generalised techniques involving probabilistic concepts. Subsequently, reliability assessments were extended to cover not just safety but also availability aspects. Earlier developed theoretical foundation gave rise to reliability technology. In order to apply this technology successfully, it has been found necessary to organise under one management multi-disciplinary groups covering computation and analysis, project assessment, research and development, and a wide ranging reliability data bank. The basic operation of the data bank is discussed as well as general applications of SRS techniques. These techniques, although developed primarily for nuclear plants, have also been found useful in their applications to non-nuclear plants and to systems in general.     

Optically activated vibrations in a micromachined silica structure

A microminiature bridge of silicon dioxide, fabricated using anisotropic etch techniques on a silicon substrate, has been set into mechanical vibration by direct interaction with a low-power laser beam. The displacement sensitivity and frequency response of the optomechanical interaction have been characterised using optical interferometry. The implications of the results for the development of radically new optical sensors are discussed.     

Wireless Networking for Monitoring and Control System of a Steel Plant

The wired networks have been traditionally used in monitoring and control of industrial plants. The trend is changing with the fast development of wireless technologies, which are challenging the wired technologies. This paper concerns with the issues related to the design of wireless network for monitoring and control of an industrial plant. In particular, measurements were conducted inside a steel plant to characterize the radio propagation environment and make a choice on a suitable technology. The channel impulse response (CIR) is measured at 1.8?GHz and from the collected data a number of link parameters are extracted. The measured CIR is also used to simulate performance of a number of data transmission formats. Finally, a number of wireless technologies are evaluated to determine their suitability to the characterized environment.     

光学相控阵技术发展概述

截至目前,光学相控阵技术已经发展了70多年,针对不同的应用方向,发展出了液晶、MEMS、光波导、相干合成等多种器件和技术方案,在激光雷达、空间光通信、高亮度激光产生、合成孔径探测等应用领域获得了初步应用。光学相控阵技术通过对光束阵列中单元光束相位的控制,从而实现阵列光束等相面的重构或精密调控,具有系统体积质量小、响应速度快、光束质量好等优点。首先介绍了光学相控阵的工作原理,然后从激光发射和远距离成像两方面对几种主流相控阵技术的发展现状、应用方向及发展趋势进行了综述,最后给出了笔者的一些思考与建议。     

Tuning Magnetic Property and Autophagic Response for Self‐Assembled Ni–Co Alloy Nanocrystals

Induction of autophagy is a common response of cells upon exposure to nanomaterials and represents both a safety concern and an application niche for engineered nanomaterials. Herein, it is reported that the magnetic property and the autophagy‐inducing activity for Ni–Co alloy nanocrystal (NC) assemblies can be differentially “tuned” through altering the material composition. A series of Ni–Co alloy NC assemblies, composed of nanoparticles (NPs) with a size of about 30 nm, can be quickly synthesized under microwave irradiation in aqueous solution. A controllable self‐assembling effect is observed due to the strong magnetic moment of NPs and external magnetic field. Interestingly, the saturation magnetization (Ms) shows a ‘roller coaster’ effect with varying component molar ratio, while the autophagy‐inducing activity and toxicity of these alloy NCs presents an elevated tendency with the increase of nickel component. The autophagic response partly contributes to the observed cellular toxicity of the NC assemblies, as inhibition of autophagy partially but significantly reduces toxicity. Therefore, through tuning the composition of the alloy, optimal Ni–Co NCs satisfying the needs of different applications such as diagnostic imaging (maximum magnetization and low autophagic response) or magnetically‐directed cancer cell killing (maximum autophagic response and sufficient magnetization) may be designed and developed.     

Optical networks research at UCL

New dynamic optical switching technologies and adaptive transmission techniques will allow increased capacity and flexibility in future core and metro networks. The Optical Networks Group at UCL has carried out research focused on these areas, in collaboration with industry and other university research groups, for over a decade. In this paper, the technical challenges to be overcome in implementing dynamic, high-capacity networks are discussed, and recent results of the group’s work are presented. New network architectures based on wavelength-routing and optical burst switching have been proposed and analysed, and the experimental demonstration of burst switching using fast wavelength-tunable lasers is described. High-capacity dense wavelength division multiplexed transmission systems, using advanced regeneration and equalisation techniques, have been studied, both theoretically, and experimentally using a dynamically reconfigurable recirculating fibre loop. Research results on advanced optical signal formats, all-optical 3R regeneration at 40 Gbit/s channel rates, adaptive analogue and digital electronic processing techniques and optical finite impulse response equalisation are presented. Finally, the development of optical performance monitoring technology, a key component of future all-optical networks, is described. The paper concludes with a prediction of future trends in optical communications research.     

植物内皮层凯氏带及其在抗盐胁迫中的作用

内皮层凯氏带是植物根中水分和离子径向运输的屏障.由于内皮层凯氏带的精细结构及化学性质等方面的研究难度较大,因此多年来进展缓慢.随着显微技术和鉴定方法的不断改进,对凯氏带的结构和功能的研究得以深入,但对其发育、化学成分及与抗盐胁迫的关系方面的报道还不多见.本文就凯氏带的结构发育、化学组成以及其在抗盐胁迫中的作用进行了综述...     

Fileless cyberattacks: Analysis and classification

With cyberattack techniques on the rise, there have been increasing developments in the detection techniques that defend against such attacks. However, cyber attackers are now developing fileless malware to bypass existing detection techniques. To combat this trend, security vendors are publishing analysis reports to help manage and better understand fileless malware. However, only fragmentary analysis reports for specific fileless cyberattacks exist, and there have been no comprehensive analyses on the variety of fileless cyberattacks that can be encountered. In this study, we analyze 10 selected cyberattacks that have occurred over the past five years in which fileless techniques were utilized. We also propose a methodology for classification based on the attack techniques and characteristics used in fileless cyberattacks. Finally, we describe how the response time can be improved during a fileless attack using our quick and effective classification technique.