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Thöne CC de Ugarte Postigo A Fryer CL Page KL Gorosabel J Aloy MA Perley DA Kouveliotou C Janka HT Mimica P Racusin JL Krimm H Cummings J Oates SR Holland ST Siegel MH De Pasquale M Sonbas E Im M Park WK Kann DA Guziy S García LH Llorente A Bundy K Choi C Jeong H Korhonen H Kubànek P Lim J Moskvitin A Muñoz-Darias T Pak S Parrish I 《Nature》2011,480(7375):72-74
Long γ-ray bursts (GRBs) are the most dramatic examples of massive stellar deaths, often associated with supernovae. They release ultra-relativistic jets, which produce non-thermal emission through synchrotron radiation as they interact with the surrounding medium. Here we report observations of the unusual GRB 101225A. Its γ-ray emission was exceptionally long-lived and was followed by a bright X-ray transient with a hot thermal component and an unusual optical counterpart. During the first 10 days, the optical emission evolved as an expanding, cooling black body, after which an additional component, consistent with a faint supernova, emerged. We estimate its redshift to be z = 0.33 by fitting the spectral-energy distribution and light curve of the optical emission with a GRB-supernova template. Deep optical observations may have revealed a faint, unresolved host galaxy. Our proposed progenitor is a merger of a helium star with a neutron star that underwent a common envelope phase, expelling its hydrogen envelope. The resulting explosion created a GRB-like jet which became thermalized by interacting with the dense, previously ejected material, thus creating the observed black body, until finally the emission from the supernova dominated. An alternative explanation is a minor body falling onto a neutron star in the Galaxy. 相似文献
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Leptin stimulates fatty-acid oxidation by activating AMP-activated protein kinase. 总被引:107,自引:0,他引:107
Yasuhiko Minokoshi Young-Bum Kim Odile D Peroni Lee G D Fryer Corinna Müller David Carling Barbara B Kahn 《Nature》2002,415(6869):339-343
Leptin is a hormone secreted by adipocytes that plays a pivotal role in regulating food intake, energy expenditure and neuroendocrine function. Leptin stimulates the oxidation of fatty acids and the uptake of glucose, and prevents the accumulation of lipids in nonadipose tissues, which can lead to functional impairments known as "lipotoxicity". The signalling pathways that mediate the metabolic effects of leptin remain undefined. The 5'-AMP-activated protein kinase (AMPK) potently stimulates fatty-acid oxidation in muscle by inhibiting the activity of acetyl coenzyme A carboxylase (ACC). AMPK is a heterotrimeric enzyme that is conserved from yeast to humans and functions as a 'fuel gauge' to monitor the status of cellular energy. Here we show that leptin selectively stimulates phosphorylation and activation of the alpha2 catalytic subunit of AMPK (alpha2 AMPK) in skeletal muscle, thus establishing a previously unknown signalling pathway for leptin. Early activation of AMPK occurs by leptin acting directly on muscle, whereas later activation depends on leptin functioning through the hypothalamic-sympathetic nervous system axis. In parallel with its activation of AMPK, leptin suppresses the activity of ACC, thereby stimulating the oxidation of fatty acids in muscle. Blocking AMPK activation inhibits the phosphorylation of ACC stimulated by leptin. Our data identify AMPK as a principal mediator of the effects of leptin on fatty-acid metabolism in muscle. 相似文献
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Non-random x-inactivation in the female mule 总被引:2,自引:0,他引:2
J L Hamerton F Giannelli F Collins J Hallett A Fryer V M McGuire R V Short 《Nature》1969,222(5200):1277-1278
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Paternal origin of new mutations in von Recklinghausen neurofibromatosis 总被引:19,自引:0,他引:19
D Jadayel P Fain M Upadhyaya M A Ponder S M Huson J Carey A Fryer C G Mathew D F Barker B A Ponder 《Nature》1990,343(6258):558-559
Von Recklinghausen neurofibromatosis (NF-1) is a common autosomal dominant disorder. The estimated new mutation rate (1 x 10(-4] is one of the highest for a human disorder. Here we report that in 12 of 14 families we have analysed, the new mutation is of paternal origin. This result is similar to that recently obtained for retinoblastoma. In other genetic disorders that show a bias towards paternal origin of new mutations, there is a marked increase in the incidence of mutations with paternal age, consistent with the mutations arising from replication errors in mitosis of spermatogonial stem cells. In retinoblastoma and NF-1, however, such paternal age effects are slight or absent. The mechanism or timing of germline mutation could therefore be different in the two cases. 相似文献
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Bowman AB Lam YC Jafar-Nejad P Chen HK Richman R Samaco RC Fryer JD Kahle JJ Orr HT Zoghbi HY 《Nature genetics》2007,39(3):373-379
Spinocerebellar ataxia type 1 (SCA1) is a dominantly inherited neurodegenerative disease caused by expansion of a glutamine tract in ataxin-1 (ATXN1). SCA1 pathogenesis studies support a model in which the expanded glutamine tract causes toxicity by modulating the normal activities of ATXN1. To explore native interactions that modify the toxicity of ATXN1, we generated a targeted duplication of the mouse ataxin-1-like (Atxn1l, also known as Boat) locus, a highly conserved paralog of SCA1, and tested the role of this protein in SCA1 pathology. Using a knock-in mouse model of SCA1 that recapitulates the selective neurodegeneration seen in affected individuals, we found that elevated Atxn1l levels suppress neuropathology by displacing mutant Atxn1 from its native complex with Capicua (CIC). Our results provide genetic evidence that the selective neuropathology of SCA1 arises from modulation of a core functional activity of ATXN1, and they underscore the importance of studying the paralogs of genes mutated in neurodegenerative diseases to gain insight into mechanisms of pathogenesis. 相似文献
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Van Houdt JK Nowakowska BA Sousa SB van Schaik BD Seuntjens E Avonce N Sifrim A Abdul-Rahman OA van den Boogaard MJ Bottani A Castori M Cormier-Daire V Deardorff MA Filges I Fryer A Fryns JP Gana S Garavelli L Gillessen-Kaesbach G Hall BD Horn D Huylebroeck D Klapecki J Krajewska-Walasek M Kuechler A Lines MA Maas S Macdermot KD McKee S Magee A de Man SA Moreau Y Morice-Picard F Obersztyn E Pilch J Rosser E Shannon N Stolte-Dijkstra I Van Dijck P Vilain C Vogels A Wakeling E Wieczorek D 《Nature genetics》2012,44(4):445-9, S1
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Bicknell LS Bongers EM Leitch A Brown S Schoots J Harley ME Aftimos S Al-Aama JY Bober M Brown PA van Bokhoven H Dean J Edrees AY Feingold M Fryer A Hoefsloot LH Kau N Knoers NV Mackenzie J Opitz JM Sarda P Ross A Temple IK Toutain A Wise CA Wright M Jackson AP 《Nature genetics》2011,43(4):356-359
Meier-Gorlin syndrome (ear, patella and short-stature syndrome) is an autosomal recessive primordial dwarfism syndrome characterized by absent or hypoplastic patellae and markedly small ears1?3. Both pre- and post-natal growth are impaired in this disorder, and although microcephaly is often evident, intellect is usually normal in this syndrome. We report here that individuals with this disorder show marked locus heterogeneity, and we identify mutations in five separate genes: ORC1, ORC4, ORC6, CDT1 and CDC6. All of these genes encode components of the pre-replication complex, implicating defects in replication licensing as the cause of a genetic syndrome with distinct developmental abnormalities. 相似文献
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