Intravital microscopy: Imaging host–parasite interactions in the brain

Intravital fluorescence microscopy (IVM) is a powerful technique for imaging multiple organs, including the brain of living mice and rats. It enables the direct visualisation of cells in situ providing a real‐life view of biological processes that in vitro systems cannot. In addition, to the technological advances in microscopy over the last decade, there have been supporting innovations in data storage and analytical packages that enable the visualisation and analysis of large data sets. Here, we review the advantages and limitations of techniques predominantly used for brain IVM, including thinned skull windows, open skull cortical windows, and a miniaturised optical system based on microendoscopic probes that can be inserted into deep tissues. Further, we explore the relevance of these techniques for the field of parasitology. Several protozoan infections are associated with neurological symptoms including Plasmodium spp., Toxoplasma spp., and Trypanosoma spp. IVM has led to crucial findings on these parasite species, which are discussed in detail in this review.     

儿童乙型流感病毒感染特点及防治的研究进展

乙型流感病毒是引起流行性感冒(简称流感)发生和流行的主要病原体之一,近年来流感高发的季节感染率呈上升趋势,儿童是乙型流感病毒感染的易感、高危群体。乙型流感病毒虽然抗原变异性较弱,但仍可引起暴发流行,严重威胁患儿的健康,因此对于儿童乙型流感病毒感染的防治至关重要。本文综合近年来国内外相关文献,从流行病学特征、临床表现、实验室检查、乙型流感病毒感染的药物治疗、免疫疗法等角度出发对乙型流感病毒感染特点及治疗进展予以综述,对乙型流感病毒进行长期有效的监测,了解儿童乙型流感病毒的感染特点,为儿童乙型流感的预防及临床诊断与防治提供理论参考。     

两种同域分布蹄蝠在开阔度不同的环境中回声定位声波的可塑性

在广西桂林研究了同域分布的大蹄蝠(Hipposideros armiger)和中蹄蝠(H.larvatus)在不同开阔度环境中回声定位声波信号的变化。用超声波仪录制自由悬挂和分别释放于人工"大棚"和"小棚"内飞行的蝙蝠的回声定位声波,使用超声分析软件分析声脉冲时程、主频率及声脉冲间隔,通过重复测量方差分析比较不同状态下的声波参数。结果表明:中蹄蝠声波的主频在悬挂状态下最高,小棚内飞行时次之,大棚内飞行最低;两种蹄蝠声波的脉冲时程和脉冲间隔在悬挂状态下最长,大棚内飞行次之,小棚内飞行最低。总之,这两种蹄蝠的回声定位声波能够随所处状态的变化而变化,可根据生境的复杂度调节声讯号,具有明显的声波可塑性。     

水生态空间红线概念、划定方法及实证研究

我国面临着多方面、复杂的水生态问题:洪涝、干旱、水质污染、水生生境丧失以及人水关系日益疏远等等。解决这些问题,不能依赖单一目标的灰色工程方法,而必须从维护和保育水生态系统的完整性出发,来系统地解决问题。为此,如何定义一个相对完整的水生态系统的边界、划定维护其安全和健康的底线,即水生态空间红线,是用生态方法综合解决水问题的基础性的工作。研究提出了以保护水生态系统的综合生态服务为核心的水生态空间红线概念;提出了以水生态安全格局构建为基础的水生态空间红线划定方法和"水生态问题分析-水生态过程模拟和评价-水生态安全等级划分-水生态安全格局判定-水生态空间红线的划定"技术流程,分别划定水资源供给保护、水文调节保护、水生命支持和水文化保护四种类型的水生态保护空间红线,在此基础上,整合为综合的水生态空间红线,它呈现为对水生态过程具有关键意义的点、线、面和空间联系所构成的空间格局,并以雁栖湖流域为例进行了实证研究。     

两种高危型HPV假病毒的构建及其在血清中和抗体测定中的应用

目的 构建人乳头瘤病毒(human papillomavirus, HPV)16型(HPV16)和18型(HPV18)假病毒,探索优化假病毒制备的条件,并利用制备的假病毒评价HPV疫苗血清抗体的中和活性。方法 将优化后的HPV16和HPV18 L1、L2和EGFP基因片段分别插入pcDNA3.1+载体中,通过多质粒共转染293FT细胞制备假病毒。对转染试剂、多质粒共转染比例、转染时间和细胞裂解时间进行摸索优化,通过测定假病毒的滴度,确定假病毒制备的最佳条件。收获的假病毒用30%的碘克沙醇作为介质进行超速离心纯化,纯化后的假病毒用于电镜观察。利用假病毒中和试验对制备的原核表达复性蛋白HPV16 L1免疫血清以及HPV16和HPV18病毒样颗粒(virus-like particles, VLP)免疫血清进行中和活性评价。结果 成功构建了假病毒,并确定了假病毒制备的最佳条件:pL1∶pL2∶pEGFP等3种质粒共转染比例为1∶0.1∶0.5,总量为4μg;转染时间为72 h,细胞裂解时间为24 h时获得的假病毒滴度最高。透射电镜观察结果显示,HPV16和HPV18假病毒颗粒基本呈规则圆形,形态上与天然病毒颗粒相似。中和试验结果显示,当用原核表达复性蛋白HPV16 L1免疫血清中和HPV16假病毒时,并不能抑制假病毒的感染活性;但HPV16和18 VLP免疫血清能明显的抑制HPV16和HPV18假病毒的感染活性。结论 成功构建并制备了2种高危型HPV假病毒,并可用于中和试验评价HPV疫苗血清抗体的中和活性。     

太空诱变玉米核不育材料花粉败育的细胞学观察(简报)

玉米是最早利用雄性不育系生产杂交种的作物之一。在玉米T型细胞质雄性不育杂交种遭受毁灭性病害侵袭之后,科学家认识到利用细胞质雄性不育制种存在潜在的遗传脆弱性,从此试图通过多种途径来创造新的雄性不育．并对雄性不育材料的遗传多样性进行研究。空间诱变育种是80年代于我国发展起来的新技术,在农作物品种改良和种质创新上已初见成效。[第一段]     

Changes in human skeletal muscle architecture and function induced by extended spaceflight

The aim of this study was to quantitatively describe the relationships between joint angles and muscle architecture (lengths (L_f) and angles (Θ_f) of fascicles) of human triceps surae [medial (MG) and lateral (LG) gastrocnemius and soleus (SOL) muscles] in vivo for three men-cosmonaut after long-duration spaceflight. Sagittal sonographs of MG, LG, SOL were taken at ankle was positioned at 15° (dorsiflexion), 0° (neutral position), +15°, and +30° (plantarflexion), with the knee at 90° at rest and after a long-duration spaceflight. At each position, longitudinal ultrasonic images of the MG and LG and SOL were obtained while the cosmonauts was relaxed from which fascicle lengths and angles with respect to the aponeuroses were determined. After space flight plantarflexor force declined significantly (26%; p < 0.001). The internal architecture of the GM, and LG, and SOL muscle was significantly altered. In the passive condition, L_f changed from 45, 53, and 39 mm (knee, 0°, ankle, −15°) to 26, 33, and 28 mm (knee, 90° ankle, 30°) for MG, LG, and SOL, respectively. Different lengths and angles of fascicles, and their changes by contraction, might be related to differences in force-producing capabilities of the muscles and elastic characteristics of tendons and aponeuroses. The three heads of the triceps surae muscle substantially differ in architecture, which probably reflects their functional roles. Differences in fiber length and pennation angle that were observed among the muscles and could be associated with differences in force production and in elastic properties of musculo-tendinous complex and aponeuroses.     

Immune dysfunction in patients with diabetes mellitus (DM)

Patients with diabetes mellitus (DM) have infections more often than those without DM. The course of the infections is also more complicated in this patient group. One of the possible causes of this increased prevalence of infections is defects in immunity. Besides some decreased cellular responses in vitro, no disturbances in adaptive immunity in diabetic patients have been described. Different disturbances (low complement factor 4, decreased cytokine response after stimulation) in humoral innate immunity have been described in diabetic patients. However, the clinical relevance of these findings is not clear. Concerning cellular innate immunity most studies show decreased functions (chemotaxis, phagocytosis, killing) of diabetic polymorphonuclear cells and diabetic monocytes/macrophages compared to cells of controls. In general, a better regulation of the DM leads to an improvement of these cellular functions. Furthermore, some microorganisms become more virulent in a high glucose environment. Another mechanism which can lead to the increased prevalence of infections in diabetic patients is an increased adherence of microorganisms to diabetic compared to nondiabetic cells. This has been described for Candida albicans. Possibly the carbohydrate composition of the receptor plays a role in this phenomenon.     

EVA dosimetry in manned spacecraft

Extra Vehicular Activity (EVA) will become a large part of the astronaut's work on board the International Space Station (ISS). It is already well known that long duration space missions inside a spacecraft lead to radiation doses which are high enough to be a significant health risk to the crew. The doses received during EVA, however, have not been quantified to the same degree. This paper reviews the space radiation environment and the current dose limits to critical organs. Results of preliminary radiation dosimetry experiments on the external surface of the BION series of satellites indicate that EVA doses will vary considerably due to a number of factors such as EVA suit shielding, temporal fluctuations and spacecraft orbit and shielding. It is concluded that measurement of doses to crew members who engage in EVA should be done on board the spacecraft. An experiment is described which will lead the way to implementing this plan on the ISS. It is expected that results of this experiment will help future crew mitigate the risks of ionising radiation in space.     

Accumulation of a tumor suppressor p53 protein in rat muscle during a space flight

We previously reported that the space environment consisting of microgravity and space radiation induced an increased level of p53 protein, a tumor suppressor gene product, in rat skin. Here, we report the increase of p53 protein in the muscles of rats that traveled into space. Rats were divided into three groups. The first group remained on earth (VC), and did not show any change in p53 protein level. The second group made a 14-day flight into space on the Second Spacelab Life Science (SLS-2) Mission (F). The third group was experimentally subjected to the same kinds of stress as those in the second group without making a space flight (SC). F and SC rats were sacrificed on day zero (F-0, SC-0) and day nine (F-9, SC-9) after return from space. F-0 rats showed a 1.5-fold increase in p53 protein level compared with that of SC-0 rats, whereas, F-9 rats showed a 1.35-fold increase in p53 protein compared with that of SC-9 rats. These results suggest that the accumulation of cellular p53 protein induced by space environments occurs not only in rat skin cells, but also in rat muscle cells.