S. R. Gevorkiantz,Forest Biometrician     

Rudolf PO 《Science (New York, N.Y.)》1958,128(3338):1557

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5-HT4(a) receptors avert opioid-induced breathing depression without loss of analgesia     

Manzke T  Guenther U  Ponimaskin EG  Haller M  Dutschmann M  Schwarzacher S  Richter DW 《Science (New York, N.Y.)》2003,301(5630):226-229

Opiates are widely used analgesics in anesthesiology, but they have serious adverse effects such as depression of breathing. This is caused by direct inhibition of rhythm-generating respiratory neurons in the Pre-Boetzinger complex (PBC) of the brainstem. We report that serotonin 4(a) [5-HT4(a)] receptors are strongly expressed in respiratory PBC neurons and that their selective activation protects spontaneous respiratory activity. Treatment of rats with a 5-HT4 receptor-specific agonist overcame fentanyl-induced respiratory depression and reestablished stable respiratory rhythm without loss of fentanyl's analgesic effect. These findings imply the prospect of a fine-tuned recovery from opioid-induced respiratory depression, through adjustment of intracellular adenosine 3',5'-monophosphate levels through the convergent signaling pathways in neurons.  相似文献   

Induction of tumors in mice by genomic hypomethylation   总被引：1，自引：0，他引：1  

Gaudet F  Hodgson JG  Eden A  Jackson-Grusby L  Dausman J  Gray JW  Leonhardt H  Jaenisch R 《Science (New York, N.Y.)》2003,300(5618):489-492

Genome-wide DNA hypomethylation occurs in many human cancers, but whether this epigenetic change is a cause or consequence of tumorigenesis has been unclear. To explore this phenomenon, we generated mice carrying a hypomorphic DNA methyltransferase 1 (Dnmt1) allele, which reduces Dnmt1 expression to 10% of wild-type levels and results in substantial genome-wide hypomethylation in all tissues. The mutant mice were runted at birth, and at 4 to 8 months of age they developed aggressive T cell lymphomas that displayed a high frequency of chromosome 15 trisomy. These results indicate that DNA hypomethylation plays a causal role in tumor formation, possibly by promoting chromosomal instability.  相似文献   

Eppendorf essay winner. Deconstructing C. elegans sensory mechanotransduction     

Goodman MB 《Science (New York, N.Y.)》2004,306(5695):427-428

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Effects of basal debris on glacier flow   总被引：1，自引：0，他引：1  

Iverson NR  Cohen D  Hooyer TS  Fischer UH  Jackson M  Moore PL  Lappegard G  Kohler J 《Science (New York, N.Y.)》2003,301(5629):81-84

Glacier movement is resisted partially by debris, either within glaciers or under glaciers in water-saturated layers. In experiments beneath a thick, sliding glacier, ice containing 2 to 11% debris exerted shear traction of 60 to 200 kilopascals on a smooth rock bed, comparable to the total shear traction beneath glaciers and contrary to the usual assumption that debris-bed friction is negligible. Imposed pore-water pressure that was 60 to 100% of the normal stress in a subglacial debris layer reduced shear traction on the debris sufficiently to halt its deformation and cause slip of ice over the debris. Slip resistance was thus less than debris shearing resistance.  相似文献   

Seawater sulfur isotope fluctuations in the Cretaceous     

Paytan A  Kastner M  Campbell D  Thiemens MH 《Science (New York, N.Y.)》2004,304(5677):1663-1665

The exogenic sulfur cycle is tightly coupled with the carbon and oxygen cycles, and therefore a central component of Earth's biogeochemistry. Here we present a high-resolution record of the sulfur isotopic composition of seawater sulfate for the Cretaceous. The general enrichment of isotopically light sulfur that prevailed during the Cretaceous may have been due to increased volcanic and hydrothermal activity. Two excursions toward isotopically lighter sulfur represent periods of lower rates of pyrite burial, implying a shift in the location of organic carbon burial to terrestrial or open-ocean settings. The concurrent changes in seawater sulfur and inorganic carbon isotopic compositions imply short-term variability in atmospheric oxygen partial pressure.  相似文献   

Microbiology. A fifth pathway of carbon fixation     

Thauer RK 《Science (New York, N.Y.)》2007,318(5857):1732-1733

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High-throughput mapping of a dynamic signaling network in mammalian cells     

Barrios-Rodiles M  Brown KR  Ozdamar B  Bose R  Liu Z  Donovan RS  Shinjo F  Liu Y  Dembowy J  Taylor IW  Luga V  Przulj N  Robinson M  Suzuki H  Hayashizaki Y  Jurisica I  Wrana JL 《Science (New York, N.Y.)》2005,307(5715):1621-1625

Signaling pathways transmit information through protein interaction networks that are dynamically regulated by complex extracellular cues. We developed LUMIER (for luminescence-based mammalian interactome mapping), an automated high-throughput technology, to map protein-protein interaction networks systematically in mammalian cells and applied it to the transforming growth factor-beta (TGFbeta) pathway. Analysis using self-organizing maps and k-means clustering identified links of the TGFbeta pathway to the p21-activated kinase (PAK) network, to the polarity complex, and to Occludin, a structural component of tight junctions. We show that Occludin regulates TGFbeta type I receptor localization for efficient TGFbeta-dependent dissolution of tight junctions during epithelial-to-mesenchymal transitions.  相似文献   

The paradox of the conservation of an endangered fish species in a Mediterranean region under agricultural intensification     

J. Jesús Casas  Juan S. Sánchez-Oliver  Ana Sanz  Miriam Furné  Cristina Trenzado  Melchor Juan  Mariano Paracuellos  María D. Suárez  Francisca Fuentes  Irene Gallego  Carlos Gil  José J. Ramos-Miras 《Biological conservation》2011,(1):253-262

We studied the relative value of natural habitats, river and coastal wetlands, and artificial habitats, irrigation canal and ponds, for the conservation of an endangered fish, Iberian toothcarp, in its southernmost area of distribution, characterised by agricultural intensification. Our results show that the bulk of the population of the Iberian toothcarp is concentrated in irrigation ponds. Natural habitats sustained null or impoverished subpopulations, and individuals showed signs of low metabolic activity. This coincided with the relatively high habitat quality observed in ponds, particularly those with submerged aquatic vegetation, in contrast with the chronic eutrophication of the coastal lagoons. In spite of a generalised aggressive management in the irrigation system, featured by periodic vegetation clearance, desiccation and biocide treatment, the subpopulation of the Iberian toothcarp thrives in it probably thanks to adequate water quality and to an active path dynamics maintained by connectivity through the canal. Agro-environmental measures are discussed for the improvement of this species conservation in natural and artificial habitats.  相似文献   

Effect of aging on lees and of three different dry yeast derivative products on Verdejo white wine composition and sensorial characteristics     

Del Barrio-Galán R  Pérez-Magariño S  Ortega-Heras M  Williams P  Doco T 《Journal of agricultural and food chemistry》2011,59(23):12433-12442

A study was made of the effect of aging on lees and of three different commercial yeast derivative products of different composition and degree of purification on the phenolic compounds, color, proteins, polysaccharides, and sensorial characteristics of white wines. The results obtained showed that the lees and yeast derivative products can interact or adsorb some of the phenolic compounds present in wines, reducing their concentration. This reduction depends on the treatment applied, the phenolic compound analyzed, and the stage of vinification or aging process. The use of lees and yeast derivative products can reduce the color intensity and the browning of the wines immediately following treatment. The monosaccharide and polysaccharide content of yeast derivative products depends on the manufacturing process and degree of purification of the product, both of which have an influence on wine treatments. After 6 months in the bottle, both the aging on lees and the treatment with commercial yeast derivative products gave rise to wines with better sensorial characteristics than in the case of the control wines.  相似文献