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121.
Zusammenfassung Die Permeabilitätsverhältnisse der Blut-Hirn-Schranke nach spezifischer Hemmung der 5-Nucleosid-Phosphatase wurden mittels Fluoreszenzmikroskopie studiert und eine Permeabilitätserhöhung nach Injektion von Nickelchlorid gefunden: Trypanblau kann dabei ins Gehirn penetrieren, was dafür spricht, dass die 5-Nucleosid-Phosphatase bei der Regulation der Kapillarpermeabilität eine bedeutende Rolle spielt. 相似文献
122.
Moreira MC Klur S Watanabe M Németh AH Le Ber I Moniz JC Tranchant C Aubourg P Tazir M Schöls L Pandolfo M Schulz JB Pouget J Calvas P Shizuka-Ikeda M Shoji M Tanaka M Izatt L Shaw CE M'Zahem A Dunne E Bomont P Benhassine T Bouslam N Stevanin G Brice A Guimarães J Mendonça P Barbot C Coutinho P Sequeiros J Dürr A Warter JM Koenig M 《Nature genetics》2004,36(3):225-227
Ataxia-ocular apraxia 2 (AOA2) was recently identified as a new autosomal recessive ataxia. We have now identified causative mutations in 15 families, which allows us to clinically define this entity by onset between 10 and 22 years, cerebellar atrophy, axonal sensorimotor neuropathy, oculomotor apraxia and elevated alpha-fetoprotein (AFP). Ten of the fifteen mutations cause premature termination of a large DEAxQ-box helicase, the human ortholog of yeast Sen1p, involved in RNA maturation and termination. 相似文献
123.
Irobi J Van Impe K Seeman P Jordanova A Dierick I Verpoorten N Michalik A De Vriendt E Jacobs A Van Gerwen V Vennekens K Mazanec R Tournev I Hilton-Jones D Talbot K Kremensky I Van Den Bosch L Robberecht W Van Vandekerckhove J Van Broeckhoven C Gettemans J De Jonghe P Timmerman V 《Nature genetics》2004,36(6):597-601
Distal hereditary motor neuropathies are pure motor disorders of the peripheral nervous system resulting in severe atrophy and wasting of distal limb muscles. In two pedigrees with distal hereditary motor neuropathy type II linked to chromosome 12q24.3, we identified the same mutation (K141N) in small heat-shock 22-kDa protein 8 (encoded by HSPB8; also called HSP22). We found a second mutation (K141E) in two smaller families. Both mutations target the same amino acid, which is essential to the structural and functional integrity of the small heat-shock protein alphaA-crystallin. This positively charged residue, when mutated in other small heat-shock proteins, results in various human disorders. Coimmunoprecipitation experiments showed greater binding of both HSPB8 mutants to the interacting partner HSPB1. Expression of mutant HSPB8 in cultured cells promoted formation of intracellular aggregates. Our findings provide further evidence that mutations in heat-shock proteins have an important role in neurodegenerative disorders. 相似文献
124.
The wild chimpanzees in Gombe National Park, Tanzania, fish for termites with flexible tools that they make out of vegetation, inserting them into the termite mound and then extracting and eating the termites that cling to the tool. Tools may be used in different ways by different chimpanzee communities according to the local chimpanzee culture. Here we describe the results of a four-year longitudinal field study in which we investigated how this cultural behaviour is learned by the community's offspring. We find that there are distinct sex-based differences, akin to those found in human children, in the way in which young chimpanzees develop their termite-fishing skills. 相似文献
125.
Protein coats deform flat lipid membranes into buds and capture membrane proteins to form transport vesicles. The assembly/disassembly cycle of the COPI coat on Golgi membranes is coupled to the GTP/GDP cycle of the small G protein Arf1. At the heart of this coupling is the specific interaction of membrane-bound Arf1-GTP with coatomer, a complex of seven proteins that forms the building unit of the COPI coat. Although COPI coat disassembly requires the catalysis of GTP hydrolysis in Arf1 by a specific GTPase-activating protein (ArfGAP1), the precise timing of this reaction during COPI vesicle formation is not known. Using time-resolved assays for COPI dynamics on liposomes of controlled size, we show that the rate of ArfGAP1-catalysed GTP hydrolysis in Arf1 and the rate of COPI disassembly increase over two orders of magnitude as the curvature of the lipid bilayer increases and approaches that of a typical transport vesicle. This leads to a model for COPI dynamics in which GTP hydrolysis in Arf1 is organized temporally and spatially according to the changes in lipid packing induced by the coat. 相似文献
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127.
Seung-Jae Lee In Hwan Lee Jeong Hun Park So-Jung Gwak Jong-Won Rhie Dong-Woo Cho Tae Jo Ko Dong Sung Kim 《科学通报(英文版)》2009,54(19):3608-3612
We developed a hybrid scaffold and a bioreactor for cartilage regeneration. The hybrid scaffold was developed as combination of two components: a biodegradable framework and hydrogel-containing chondrocytes. We performed the MTT cell proliferation assay to compare the proliferation and viability of chondrocytes on three types of scaffolds: an aiginate gel, the hybrid scaffold, and an alginate sponge. Cells were encapsulated in 2% agarose gel. The bioreactor consisted of a circulation system and a compression system. We performed dynamic cell culture on these agarose gels in the bioreactor for 3 days. 相似文献
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129.
Daniela Aparecida Savariz Bôlla Fernando Carvalho Jairo José Zocche Alexandre Bianco João Antônio de Bittencourt Vitto Raphael dos Santos 《Journal of Natural History》2017,51(47-48):2947-2953
Bats (Chiroptera), one of the most diverse groups in terms of taxonomy, morphology and ecology, are known for their nocturnal behaviour of flight and feeding. Although there is no consensus on the evolution of nocturnality in bats, many authors mention risk of predation, overheating, competition and mobbing by non-competitor species as arguments to justify nocturnal instead of daytime flight in bats. Herein we describe the first records of three genera of phyllostomid bats flying, foraging and drinking water during daytime in the Brazilian Amazon. All taxa were recorded drinking water, and some Phyllostomus sp. individuals were recorded foraging on termites, alongside birds. Risk of dehydration and overheating in roosts, as well as low competition in daytime, may explain the emergence of phyllostomid bats before sunset. 相似文献
130.
Forecasting the US Term Structure of Interest Rates Using Nonparametric Functional Data Analysis
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In this paper we consider a novel procedure to forecasting the US zero coupon bond yields for a continuum of maturities by using the methodology of nonparametric functional data analysis (NP‐FDA). We interpret the US yields as curves since the term structure of interest rates defines a relation between the yield of a bond and its maturity. Within the NP‐FDA approach, each curve is viewed as a functional random variable and the dynamics present in the sample are modeled without imposing any parametric structure. In order to evaluate forecast the performance of the proposed estimator, we consider forecast horizons h = 1,3,6,12… months and the results are compared with widely known benchmark models. Our estimates with NP‐FDA present predictive performance superior to its competitors in many situations considered, especially for short‐term maturities. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献