Geochemistry. Are volcanic gases serial killers?     

Scaillet B 《Science (New York, N.Y.)》2008,319(5870):1628-1629

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Endocannabinoid hydrolysis generates brain prostaglandins that promote neuroinflammation   总被引：2，自引：0，他引：2  

Nomura DK  Morrison BE  Blankman JL  Long JZ  Kinsey SG  Marcondes MC  Ward AM  Hahn YK  Lichtman AH  Conti B  Cravatt BF 《Science (New York, N.Y.)》2011,334(6057):809-813

Phospholipase A(2)(PLA(2)) enzymes are considered the primary source of arachidonic acid for cyclooxygenase (COX)-mediated biosynthesis of prostaglandins. Here, we show that a distinct pathway exists in brain, where monoacylglycerol lipase (MAGL) hydrolyzes the endocannabinoid 2-arachidonoylglycerol to generate a major arachidonate precursor pool for neuroinflammatory prostaglandins. MAGL-disrupted animals show neuroprotection in a parkinsonian mouse model. These animals are spared the hemorrhaging caused by COX inhibitors in the gut, where prostaglandins are instead regulated by cytosolic PLA(2). These findings identify MAGL as a distinct metabolic node that couples endocannabinoid to prostaglandin signaling networks in the nervous system and suggest that inhibition of this enzyme may be a new and potentially safer way to suppress the proinflammatory cascades that underlie neurodegenerative disorders.  相似文献   

Cerebellum shapes hippocampal spatial code     

Rochefort C  Arabo A  André M  Poucet B  Save E  Rondi-Reig L 《Science (New York, N.Y.)》2011,334(6054):385-389

Spatial representation is an active process that requires complex multimodal integration from a large interacting network of cortical and subcortical structures. We sought to determine the role of cerebellar protein kinase C (PKC)-dependent plasticity in spatial navigation by recording the activity of hippocampal place cells in transgenic L7PKCI mice with selective disruption of PKC-dependent plasticity at parallel fiber-Purkinje cell synapses. Place cell properties were exclusively impaired when L7PKCI mice had to rely on self-motion cues. The behavioral consequence of such a deficit is evidenced here by selectively impaired navigation capabilities during a path integration task. Together, these results suggest that cerebellar PKC-dependent mechanisms are involved in processing self-motion signals essential to the shaping of hippocampal spatial representation.  相似文献   

Preserved feedforward but impaired top-down processes in the vegetative state     

Boly M  Garrido MI  Gosseries O  Bruno MA  Boveroux P  Schnakers C  Massimini M  Litvak V  Laureys S  Friston K 《Science (New York, N.Y.)》2011,332(6031):858-862

Frontoparietal cortex is involved in the explicit processing (awareness) of stimuli. Frontoparietal activation has also been found in studies of subliminal stimulus processing. We hypothesized that an impairment of top-down processes, involved in recurrent neuronal message-passing and the generation of long-latency electrophysiological responses, might provide a more reliable correlate of consciousness in severely brain-damaged patients, than frontoparietal responses. We measured effective connectivity during a mismatch negativity paradigm and found that the only significant difference between patients in a vegetative state and controls was an impairment of backward connectivity from frontal to temporal cortices. This result emphasizes the importance of top-down projections in recurrent processing that involve high-order associative cortices for conscious perception.  相似文献   

Psychology. Happy people live longer     

Frey BS 《Science (New York, N.Y.)》2011,331(6017):542-543

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Molecular biology. Breaking the silence     

Owen-Hughes T  Bruno M 《Science (New York, N.Y.)》2004,303(5656):324-325

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Comment on "Status and trends of amphibian declines and extinctions worldwide"     

Pimenta BV  Haddad CF  Nascimento LB  Cruz CA  Pombal JP 《Science (New York, N.Y.)》2005,309(5743):1999; author reply 1999

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Cross-linking cellular prion protein triggers neuronal apoptosis in vivo     

Solforosi L  Criado JR  McGavern DB  Wirz S  Sánchez-Alavez M  Sugama S  DeGiorgio LA  Volpe BT  Wiseman E  Abalos G  Masliah E  Gilden D  Oldstone MB  Conti B  Williamson RA 《Science (New York, N.Y.)》2004,303(5663):1514-1516

Neuronal death is a prominent, but poorly understood, pathological hallmark of prion disease. Notably, in the absence of the cellular prion protein (PrPC), the disease-associated isoform, PrPSc, appears not to be intrinsically neurotoxic, suggesting that PrPC itself may participate directly in the prion neurodegenerative cascade. Here, cross-linking PrPC in vivo with specific monoclonal antibodies was found to trigger rapid and extensive apoptosis in hippocampal and cerebellar neurons. These findings suggest that PrPC functions in the control of neuronal survival and provides a model to explore whether cross-linking of PrPC by oligomeric PrPSc can promote neuronal loss during prion infection.  相似文献   

PAMELA measurements of cosmic-ray proton and helium spectra     

Adriani O  Barbarino GC  Bazilevskaya GA  Bellotti R  Boezio M  Bogomolov EA  Bonechi L  Bongi M  Bonvicini V  Borisov S  Bottai S  Bruno A  Cafagna F  Campana D  Carbone R  Carlson P  Casolino M  Castellini G  Consiglio L  De Pascale MP  De Santis C  De Simone N  Di Felice V  Galper AM  Gillard W  Grishantseva L  Jerse G  Karelin AV  Koldashov SV  Krutkov SY  Kvashnin AN  Leonov A  Malakhov V  Malvezzi V  Marcelli L  Mayorov AG  Menn W  Mikhailov VV  Mocchiutti E  Monaco A  Mori N  Nikonov N  Osteria G  Palma F  Papini P  Pearce M 《Science (New York, N.Y.)》2011,332(6025):69-72

Protons and helium nuclei are the most abundant components of the cosmic radiation. Precise measurements of their fluxes are needed to understand the acceleration and subsequent propagation of cosmic rays in our Galaxy. We report precision measurements of the proton and helium spectra in the rigidity range 1 gigavolt to 1.2 teravolts performed by the satellite-borne experiment PAMELA (payload for antimatter matter exploration and light-nuclei astrophysics). We find that the spectral shapes of these two species are different and cannot be described well by a single power law. These data challenge the current paradigm of cosmic-ray acceleration in supernova remnants followed by diffusive propagation in the Galaxy. More complex processes of acceleration and propagation of cosmic rays are required to explain the spectral structures observed in our data.  相似文献   

Two class III chitin synthases specifically localized in appressoria and haustoria of Puccinia graminis f. sp. tritici     

Katja Broeker  Sabine Fehser  Klaus B. Tenberge  Bruno M. Moerschbacher 《Physiological and Molecular Plant Pathology》2011,76(1):27-33

Rust fungi like Puccinia graminis f. sp. tritici are known to change their cell wall properties upon entering the plant tissue. Immunohistochemistry revealed the cellular localization of two class III chitin synthase isoforms in rust mycelia developing on and in the host plant. Isoform IIIa is restricted to fungal infection structures growing on the surface of the plant, such as germ tubes and, predominantly, appressoria. Isoform IIIb is found exclusively in haustoria developed inside the plant. Thus, the rust fungus uses at least two chitin synthase isoforms with specialized functions in the differentiation of infection structures during the biotrophic plant-pathogen-interaction.  相似文献