Light sheet microscopes: Novel imaging toolbox for visualizing life’s processes

Capturing dynamic processes in live samples is a nontrivial task in biological imaging. Although fluorescence provides high specificity and contrast compared to other light microscopy techniques, the photophysical principles of this method can have a harmful effect on the sample. Current advances in light sheet microscopy have created a novel imaging toolbox that allows for rapid acquisition of high-resolution fluorescent images with minimal perturbation of the processes of interest. Each unique design has its own advantages and limitations. In this review, we describe several cutting edge light sheet microscopes and their optimal applications.     

Spectrum of Cav1.4 dysfunction in congenital stationary night blindness type 2

Defective retinal synaptic transmission in patients affected with congenital stationary night blindness type 2 (CSNB2) can result from different dysfunction phenotypes in Cav1.4 L-type calcium channels. Here we investigated two prototypical Cav1.4 variants from either end of the functional spectrum. Using whole-cell and single-channel patch-clamp techniques, we provide analysis of the biophysical characteristics of the point mutation L860P and the C-terminal truncating mutation R1827X. L860P showed a typical loss-of-function phenotype attributed to a reduced number of functional channels expressed at the plasma membrane as implied by gating current and non-stationary noise analyses. This phenotype can be rationalized, because the inserted proline is predicted to break an amphipatic helix close to the transmembrane segment IIIS1 and thus to reduce channel stability and promote misfolding. In fact, L860P was subject to an increased turnover. In contrast, R1827X displayed an apparent gain-of-function phenotype, i.e., due to a hyperpolarizing shift of the IV-curve and increased single-channel activity. However, truncation also resulted in the loss of functional C-terminal modulation and thus unmasked calcium-dependent inactivation. Thus R1827X failed to support continuous calcium influx. Current inactivation curtails the dynamic range of photoreceptors (e.g., when adapting to variation in illumination). Taken together, the analysis of two representative mutations that occur in CSNB2 patients revealed fundamental differences in the underlying defect. These may explain subtle variations in the clinical manifestation and must be taken into account, if channel function is to be restored by pharmacochaperones or related approaches.     

荷叶离褶伞生物学特性研究

荷叶离褶伞菌丝生长的温度范围是5~35℃,最适温度25℃;子实体分化的温度范围13~22℃,最适温度19℃;0~3℃的温差有利于子实体的分化,温差大于9℃子实体不能形成;孢子萌发的温度范围是10~25℃,最适温度20℃;菌丝能在pH4~11范围内生长,最适pH4~5;菌丝和孢子的致死温度分别是45℃30min和50℃15min。能利用淀粉、蔗糖、葡萄糖、果糖、玉米粉、乳糖和甘露糖作碳源,但蔗糖和葡萄糖为碳源生长势强,果糖生长势弱;甘氨酸、蛋白胨、硫酸铵、黄豆粉、硝酸铵、谷氨酸和麦麸均可作为氮源,在麦麸上生长速度快,长势旺盛;硫酸铵、硝酸铵和谷氨酸虽能作为氮源,但长势很弱;能在C/N15/1~50/1的范围内生长,C/N为50/1时生长速度最快。在完全黑暗的条件下不能形成子实体,连续光照和12h光暗交替两种处理都可形成子实体,且两种处理间差异不显著。     

营养液酸碱度及光照强度对魔芋生长的影响

研究了pH3~10的不同营养液酸碱度在不同光照强度下对魔芋的生长状况及软腐病的发生率的影响。结果表明:魔芋最适宜的营养液环境为pH6~8,光照应控制在7000 Lux以下。在实际栽培中,应根据不同的光照强度适当调节营养液的酸碱度,以控制病害的发生。     

马占相思夜间树干液流的分配及其对整树蒸腾估算的影响

采用Granier热消散探针测定了马占相思(Acacia mangium)的树干液流,结合Li-6400光合测定系统测定的夜间叶片气孔导度和蒸腾,将夜间液流区分为夜间树干水分补充和叶片气孔蒸腾。叶片的蒸腾作用微弱,因此,夜间液流主要用于补充贮水部位的水分亏缺。马占相思夜间水分补充量年内和年际的变化不明显,树形特征的差异是解释夜间水分补充量变化的重要因子,夜间水分补充量对于整树蒸腾量的贡献因季节和树木径级的不同而有明显变化,但对整树总蒸腾量计算造成的误差可以忽略。     

Herders' Perceptions, Practice, and Problems of Night Grazing in the Sahel: Case Studies from Niger

A survey was conducted from February to June of 1997 among livestock herders in two villages of Niger, Kodey and Toukounous, on their perceptions, practice, and problems of night grazing. Cattle and sheep were the species that were taken out for night grazing by the herders. Small herd size and labor constraints were mentioned as the principal reasons for not practicing night grazing. Major benefits of night grazing included good body condition, herd growth, increased milk production, prevention of diseases, and reduction in herd mortality. Insecurity, difficulty in staying awake at night, labor constraints, and damage to crops by animals were given as problems of night grazing. According to the herders, grazing time (duration) during the day and night was shorter in the wet season than in the dry season. In the wet season animals were herded (followed and closely supervised by herders), whereas in the dry season, animals were mostly left to range freely in both villages. In general, children herded the animals during the day, while adults were responsible for night-time herding. Herders' perceptions on night grazing as regards animal production parameters such as weight development, water consumption, fecal output and feeding behavior are consistent with available experimental results. Therefore, future technical research needs to recognize the constraints faced by herders and determine how to overcome them to improve technical and economic efficiency.     

An LCA study on sludge retreatment processes in Japan

The majority of night soil (human excrements) is source separated from other sewage water and treated at night soil treatment plants in Japan. Efforts have been made to achieve material recovery from this organic mass, together with other organic wastes such as kitchen wastes and manure, by expanding the functions at night soil treatment plants. These facilities with expanded function are called ‘sludge retreatment centers’, which are promoted by the Japanese Ministry of Health and Welfare. Potential environmental impacts of sludge retreatment using two presently available systems in Japan are analyzed for comparison. Systems compared are: 1) Mebius system, a high-speed fermentation process with methane gas recovery and compost production and 2) a comparable system with a basic composting process. The functional unit for this study is concurrent treatment of 40 t/d of kitchen waste, 40 m³/d of night soil, and 60 m³/d of private sewage treatment tank sludge. Impact assessment on Global Warming (IPCC 1996, 20 yrs.), Acidification Potential (De Leeuv — AP), Eutrophication Potential (De Leeuv- EP) and Resource Index (Fava/SETAC & Heijungs) all indicated that sludge retreatment with Mebius system provides a better environmental performance. The main reasons are: 1) production of power using recovered methane and 2) reduction of sludge volume by digestion, which leads to reduction of fuel required for sludge drying. The collection and treatment of night soil and kitchen wastes involves many economic and social factors. Therefore, more studies with different functional units on these systems should be made to obtain a more complete picture that can be used for decision-making processes. The results of this study can be used as a starting point.     

紫蓬山区三种鹭雏鸟的食物多样性比较

池鹭(Ａｒｄｅｏｌａｂａｃｃｈｕｓ)、白鹭(Ｅｇｒｅｔｔａｇａｒｚｅｔｔａ)和夜鹭(Ｎｙｃｔｉｃｏｒａｘｎｙｃｔｉｃｏｒａｘ)4～7月在紫蓬山区国家级森林公园集群繁殖[7]。有关三者的繁殖生态报道较多[6,10～12,23],但甚少较系统的研究雏鸟的食性,尚缺乏通过食性研究进行鹭类资源管理和生物多样性保护方面的探讨。笔者1996年4～7月在紫蓬山区国家级森林公园的圆通山对池鹭、白鹭和夜鹭雏鸟的食性进行了观察,整理报道如下。1　工作方法收集称量雏鸟吐出的食物[13],或逆向挤压嗉囊使其吐出食物,统计食物的种类、数量。食物量百分比、食物…