Real-time imaging of the dynamics of secretory granules in growth cones

Secretory granules containing a hybrid protein consisting of the regulated secretory protein tissue plasminogen activator and an enhanced form of green fluorescent protein were tracked at high spatial resolution in growth cones of differentiated PC12 cells. Tracking shows that granules, unlike synaptic vesicles, generally are mobile in growth cones. Quantitative analysis of trajectories generated by granules revealed two dominant modes of motion: diffusive and directed. Diffusive motion was observed primarily in central and peripheral parts of growth cones, where most granules diffused two to four orders of magnitude more slowly than comparably sized spheres in dilute solution. Directed motion was observed primarily in proximal parts of growth cones, where a subset of granules underwent rapid, directed motion at average speeds comparable to those observed for granules in neurites. This high-resolution view of the dynamics of secretory granules in growth cones provides insight into granule organization and release at nerve terminals. In particular, the mobility of granules suggests that granules, unlike synaptic vesicles, are not tethered stably to cytoskeletal structures in nerve terminals. Moreover, the slow diffusive nature of this mobility suggests that secretory responses involving centrally distributed granules in growth cones will occur slowly, on a time scale of minutes or longer.     

Use of a crude extract or purified antigen from first‐instar cattle grubs,Hypoderma lineatum,for the detection of anti‐Hypoderma antibodies in free‐ranging cervids from southern Spain

During the 2003–2005 hunting seasons, a total of 120 Cervidae, including 39 red deer (Cervus elaphus hispanicus) and 81 fallow deer (Dama dama), were examined for subcutaneous myiasis. Animals were shot from January to June in southern Spain. Specific antibodies against Hypodermatinae (Diptera: Oestridae) were detected by indirect enzyme‐linked immunosorbent assay (iELISA) using a crude larval extract (CLE) and a purified antigen [hypodermin C (HC)] obtained from first instars of Hypoderma lineatum (De Villers) (Diptera: Oestridae). Hypoderma actaeon Brauer was the only species detected in this study, which represents the first confirmation of this species in fallow deer from Spain. The overall prevalence of animals presenting subcutaneous larvae (14.2%) was considerably lower than the prevalences determined by iELISA with CLE (43.3%) and HC (40.0%). Red deer showed a higher prevalence of Hypoderma than fallow deer. The concordance between larval examination during the hunting season and iELISA using both antigens was low, whereas the concordance between the CLE and HC ELISAs was good. Larval antigens obtained from H. lineatum constitute a good tool for the diagnosis of H. actaeon in Cervidae, especially when the hunting season does not coincide with the maximum presence of larvae on the back.     

The Dutch N-cascade in the European perspective

The Netherlands is "well known" for its nitrogen problems; it has one of the highest reactive nitrogen (Nr) emission densities in the world. It is a small country at the delta of several large European rivers. Ever since the industrial revolution, there has been a growing excess of nutrients and related emissions into the atmosphere (ammonia, nitrogen oxides and nitrous oxide) and into groundwater and surface water (nitrate), leading to a large range of cascading environmental impacts. Vehicular traffic, sewage and animal husbandry are the main sources of oxidized and reduced forms of Nr. This paper provides an overview of the origin and fate of nitrogen in the Netherlands, the various reported impacts of nitrogen, the Dutch and European policies to reduce nitrogen emissions and related impacts. In addition, ways are presented to go forward to potentially solve the problems in a European perspective. Solutions include the improvement of nitrogen efficiencies in different systems, technological options and education.     

肠内营养对乳腺癌术后化疗患者肠道菌群及生活质量的影响

目的研究肠内营养对乳腺癌术后化疗患者肠道菌群、生活质量、营养指标水平的影响。方法选取2012年7月至2018年1月于我院进行乳腺癌术后化疗的91例女性乳腺癌患者为研究对象,根据是否进行肠内营养将患者分为肠内营养组和对照组,观察化疗前后2组患者肠道菌群、生活质量、营养指标水平的变化及不良反应发生情况。结果治疗前2组患者肠道菌群、生活质量、营养指标水平差异无统计学意义(均P0.05)。治疗后,肠内营养组患者肠道双歧杆菌数量为(6.7±0.5)lg CFU/g、乳杆菌数量为(8.5±0.4)lg CFU/g,均显著高于治疗前,同时显著高于对照组(均P0.05)。治疗后肠内营养组患者出现反酸、腹胀、便秘等胃肠道不良反应的比例与对照组比较差异无统计学意义(均P0.05)。治疗后两组患者总体健康、认知功能、情绪功能、角色功能、社会功能、活力、躯体疼痛、躯体功能评分显著高于治疗前(均P0.05),且肠内营养组患者生活质量各指标的评分显著高于对照组(均P0.05)。治疗后肠内营养组患者血清总蛋白(TB)、血清清蛋白(ALB)、血清前清蛋白(PA)、转铁蛋白(TF)水平均显著高于对照组(均P0.05)。结论肠内营养可预防乳腺癌术后化疗患者肠道菌群的紊乱及营养不良的发生,安全有效,有助于提高乳腺癌患者的生活质量。     

Hybridization between diploid Centaurea pseudophrygia and tetraploid C. jacea (Asteraceae): the role of mixed pollination,unreduced gametes,and mentor effects

We studied hybridization between the diploid Centaurea pseudophrygia and the tetraploid C. jacea by performing crossing experiments and screening natural populations using flow cytometry. The experiments confirm that the studied species exhibit strong reproductive isolation. Interspecific hybrids were formed at a low frequency, including triploids (originating from reduced gametes) and tetraploids (involving unreduced gametes of the diploids). In contrast, hybrids were almost absent among seeds and adult plants of natural mixed populations and among the offspring from experimental pollinations with a mixture of pollen of both ploidy levels. We found that mixed pollination is an important mechanism for preventing hybridization between plants of different ploidy levels and sustaining the reproduction of the tetraploids. A mentor effect (induced selfing in the presence of pollen of different ploidy levels) was observed in both diploids and tetraploids, reinforcing the reproductive isolation between cytotypes. Higher ploidy levels (pentaploid, hexaploid) involving unreduced gametes of the tetraploid species were identified. Notably, pentaploids were discovered for the first time in Centaurea sect. Jacea. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104 , 93–106.     

马卵母细胞体外成熟的初步研究

采用抽吸法和切割法两种采卵方法收集马卵母细胞,显示采用切割法的卵母细胞回收率为83%,高于抽吸法的回收率46.5%(P＜0.05),在卵母细胞的成熟上,使用M199和DMEM/F12两种培养液为基础液的成熟体系,紧凑型(Cp)COCs和扩展型(Ex)COCs在以M199为基础液和以DMEM/F12为基础液的培养液中的卵母细胞成熟率分别为41.7%和64.7%、46.7%和66.7%,差异不显著(P＞0.05).两种培养体系中成熟的Cp COCs采用Ionomycin与6-DMAP和CHX联合激活,在以M199和以DMEM/F12为基础液的培养液中成熟的卵母细胞的卵裂率分别为45%和57.1%,差异不明显(P＞0.05).     

黑素皮质素受体-4的研究进展

黑素皮质素受体 4 (MC4R)是人类中枢神经系统中参与调节肥胖症发生的重要因素 ,可调节动物的体重和采食量。自MC4R基因克隆以来 ,学者们对MC4R的结构 ,生理功能 ,调控 ,作用机制及其基因突变与体重的关系等方面进行了大量的研究。     

运用稳定同位素技术分析大宁河主要鱼类营养层级

运用氮稳定同位素技术分析了大宁河静水水域和流水河段主要鱼类的氮稳定同位素比值和营养层级,并对静水水域不同水文时期相同鱼类的营养层级进行了比较研究。结果表明, 颗粒有机物(POM)氮稳定性同位素变化幅度较大, 并存在季节差异。大宁河下游静水水域鱼类15N 值范围为4.5417.51, 营养级处于1.513.88, 平均营养层级为2.49;上游流水水域鱼类的15N 值范围为2.2510.81, 营养层级范围为1.494.01, 平均营养层级为2.87。大宁河上游鱼类的平均营养层级大于下游静水水域, 可能是由于上游底栖生物丰富, 鱼类倾向摄食适口性更高的动物性食物而导致。大宁河下游静水水域汛期的鱼类营养层级较非汛期的值显著降低, 可能是因为汛期的水文扰动影响鱼类摄食中间捕食者, 以及水位的降低导致鱼类食物竞争增加迫使其摄食低营养水平的食物。重复基准生物采样建立精确充足的基线值以及确定合适的富集度,是提高营养层级评估准确性的重要手段。       

利手、优势足及扣手的遗传方式初探

采用Slater区分单基因和多基因遗传的计算模式及Smith无偏分析方法对21个家系资料的分析表明：利手、优势足、扣手特征均为常染色体单基因显性遗传,R型为显性性状。虽然环境因素对这类特征的表现也有一定的影响,但遗传因素仍起主要作用。 Abstract:The data of 21 families were analyzed by the method of Slater's calculating model to differentiate between single-gene and multi-gene heredity and by the method of non-deviation analysis.The results showed that the hereditary mode of handedness or preferential foot or hand-clasping is the dominant heredity of single gene of autosome,and the right type of all of them is the dominant character.In a way,although environmental factors affected the phenotypes of these characters,hereditary factors were also the decisive ones.     

利手、优势足及扣手的遗传方式初探

采用Slater区分单基因和多基因遗传的计算模式及Smith无偏分析方法对21个家系资料的分析表明：利手、优势足、扣手特征均为常染色体单基因显性遗传,R型为显性性状。虽然环境因素对这类特征的表现也有一定的影响,但影响因素仍起主要作用。