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The Ethiopian Bush-crow Zavattariornis stresemanni is an endangered, co-operatively breeding southern Ethiopian endemic with a remarkably restricted range (c. 6 000 km2). The species’ range was recently found to be almost perfectly predicted by an envelope of cooler, drier and more seasonal climate than surrounding areas, but the proximate determinants of this range restriction remain unclear. We assessed whether specialisation in diet or foraging may restrict the range of the species by conducting foraging watches to determine prey composition, augmented by observations of opportunistic foraging techniques, and by comparing our results to previously published information on diet. Prey composition comprised a range of arthropods, such as insect larvae (62.7%), beetles (Coleoptera) (15.6%), and grasshoppers and crickets (Orthoptera) (11.8%). Prey was primarily obtained by pecks above ground (74.2%) but also frequently dug up (23.8%). Prey capture was most successful during pecks and we also found chicks were preferentially fed larger prey items over smaller ones by adults. We documented opportunistic behaviours such as nest-raiding and ox-pecking. Diet and foraging are varied and unspecialised, and therefore do not appear to explain the restricted range of the Ethiopian Bush-crow.  相似文献   
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Mutations of Cu/Zn superoxide dismutase 1 (SOD1), a metalloenzyme catalyzing the conversion of superoxide anion to hydrogen peroxide (H(2)O(2)), are linked to motor neuron degeneration. Transgenic mouse strains overexpressing wild-type human SOD1 (Tg-SOD1) were shown to have mitochondrial swelling, vacuolization, or learning and memory deficits and are widely used for biochemical, genetic, and cognitive studies; this, along with the advent of advanced proteomic methods, made us investigate protein expression in hippocampus. Hippocampal tissues of wild-type, hemizygous, and homozygous Tg-SOD1 mice were isolated and used for two-dimensional gel electrophoresis with subsequent matrix-assisted laser desorption/ionization-time of flight identification. We identified several synaptosomal, neuronal, antioxidant, and mitochondrial proteins in hippocampus, and expression levels of syntaxin-binding protein 1, N-ethylmaleimide-sensitive factor, synaptosomal-associated protein 25, dynamin-1, neurofilament triplet L protein, neurofilament triplet M protein, neuronal tropomodulin, and neuronal protein 25 were significantly decreased in Tg-SOD1. None of the antioxidant proteins were altered except mouse SOD1. Mitochondrial ATP synthase alpha/beta chain and elongation factor Tu were aberrant in Tg-SOD1. We conclude that derangement of neuronal and mitochondrial proteins may indicate synaptosomal and neuronal loss in Tg-SOD1 hippocampus, already reported in morphological terms. This observation is of relevance to understanding brain deficits in Down syndrome, as SOD1 is encoded on chromosome 21.  相似文献   
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红腹锦鸡肺的组织结构与微血管构筑   总被引:2,自引:0,他引:2  
为了了解红腹锦鸡(Chroysolophus pictus)肺的微细结构和微血管构筑特征,为呼吸生物学研究提供形态学依据,用组织学方法和微血管铸型技术在光镜和扫描电镜下观察研究了红腹锦鸡肺的组织结构与微血管构筑情况。结果表明,红腹锦鸡肺主要由各级支气管构成,从三级支气管上呈辅射状分出许多呼吸毛细管(微气管),并相互吻合成网状,呼吸毛细管外面包围有丰富的毛细血管;红腹锦鸡肺毛细血管垂直围绕在各微气管外,并相互吻合成密集的立体微血管网;毛细血管管径4.5~7.0μm,微气管直径11~50μm。并对肺微血管构筑情况与呼吸效率的关系作了探讨。  相似文献   
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Premature ageing, one of the characteristics of Down syndrome (DS), may involve oxidative stress and impairment of proteasome activity. Transgenic mice overexpressing the human copper/zinc superoxide dismutase (SOD1) gene are one of the first murine models for DS and it has been shown that SOD1 overexpression might be either deleterious or beneficial. Here, we show a reduction in proteasome activities in the cortex of SOD1 transgenic mice and an associated increase in the content of oxidized SOD1 protein. As we demonstrate that in vitro oxidized SOD can inhibit purified proteasome peptidase activities, modified SOD1 might be partially responsible for proteasome inhibition shown in SOD1 transgenic mice.  相似文献   
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Dysregulation of the Hepatocyte growth factor (HGF)/c-Met signaling axis upregulates diverse tumor cell functions, including cell proliferation, survival, scattering and motility, epithelial-to-mesenchymal transition (EMT), angiogenesis, invasion, and metastasis. (-)-Oleocanthal is a naturally occurring secoiridoid from extra-virgin olive oil, which showed antiproliferative and antimigratory activity against different cancer cell lines. The aim of this study was to characterize the intracellular mechanisms involved in mediating the anticancer effects of (-)-oleocanthal treatment and the potential involvement of c-Met receptor signaling components in breast cancer. Results showed that (-)-oleocanthal inhibits the growth of human breast cancer cell lines MDA-MB-231, MCF-7 and BT-474 while similar treatment doses were found to have no effect on normal human MCF10A cell growth. In addition, (-)-oleocanthal treatment caused a dose-dependent inhibition of HGF-induced cell migration, invasion and G1/S cell cycle progression in breast cancer cell lines. Moreover, (-)-oleocanthal treatment effects were found to be mediated via inhibition of HGF-induced c-Met activation and its downstream mitogenic signaling pathways. This growth inhibitory effect is associated with blockade of EMT and reduction in cellular motility. Further results from in vivo studies showed that (-)-oleocanthal treatment suppressed tumor cell growth in an orthotopic model of breast cancer in athymic nude mice. Collectively, the findings of this study suggest that (-)-oleocanthal is a promising dietary supplement lead with potential for therapeutic use to control malignancies with aberrant c-Met activity.  相似文献   
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用蛙胫前肌小束为材料,研究了提高胞外钾[K+]O对咖啡因挛缩的作用。[K+]O从2mmol/L提高到10或25mmol/L,由3mmol/L咖啡因引起的挛缩明显增强。以PKC/PC(PKC和PC分别为在高钾和正常钾条件下的咖啡因挛缩)表示的咖啡因挛缩增强,依赖[K+]O和高钾作用时间。随着10mmol/L[K+]O作用时间延长,直至10min,增强逐渐增加。但是,25mmol/L[K+]O作用1min时增强达到最大,然后下降到对照。PKC/PC变化时程不能用高钾引起的去极化解释,而与由相似[K+]O引起的胞浆自由钙变化时程相符。提示,至少在蛙骨骼肌,高钾引起的咖啡因挛缩增强主要是由胞浆自由钙升高引起的。  相似文献   
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Cu/Zn-superoxide dismutase 1 (SOD1), encoded on chromosome 21, is a key enzyme in metabolism of oxygen free radicals and oxidative stress. Transgenic mice overexpressing human SOD1 (Tg-hSOD1) are useful model for Down syndrome (trisomy 21) and familial amyotrophic lateral sclerosis (ALS). It was shown recently that Tg-hSOD1 mice develop a characteristic set of neurodegenerative changes in hippocampus and we therefore decided to study differential protein expression patterns, constructing a mouse hippocampal proteome map using two-dimensional electrophoresis (2-DE) with in-gel digestion of spots followed by matrix-assisted laser desorption/ionisation-time of flight (MALDI-TOF) identification and quantitatively compared protein profiles between non-transgenic mice, hemizygous and homozygous Tg-hSOD1 mice. In total 1056 spots were analysed, resulting in the identification of 445 polypeptides that were the products of 157 different genes. Among these a series of proteins involved in scaffolding, metabolism, signaling and other functions were deranged. Our findings suggest that overexpressed SOD1 directly or by generating reactive oxygen species may lead to aberrant protein expressional patterns that in turn may lead to or reflect neurodegeneration observed in this animal model.  相似文献   
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Rapid progress in genome research creates a wealth of information on the functional annotation of mammalian genome sequences. However, as we accumulate large amounts of scientific information we are facing problems of how to integrate and relate the data produced by various genomic approaches. Here, we propose the novel concept of an organ atlas where diverse data from expression maps to histological findings to mutant phenotypes can be queried, compared and visualized in the context of a three-dimensional reconstruction of the organ. We will seek proof of concept for the organ atlas by elucidating genetic pathways involved in development and pathophysiology of the kidney. Such a kidney atlas may provide a paradigm for a new systems-biology approach in functional genome research aimed at understanding the genetic bases of organ development, physiology and disease.Key Words: EuReGene, kidney, genome, development, pathophysiology, genetics  相似文献   
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