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Neuron-glia adhesion is inhibited by antibodies to neural determinants 总被引:10,自引:0,他引:10
Suspensions of embryonic chick neuronal cells adhered to monolayers of glial cells, but few neurons bound to control monolayers of fibroblastic cells from meninges or skin. Neuronal cell-glial cell adhesion was inhibited by prior incubation of the neurons with Fab' fragments of antibodies to neuronal membranes. In contrast, antibodies to the neural cell adhesion molecule (N-CAM) did not inhibit the binding. These results suggest that a specific adhesive mechanism between neurons and glial cells exists and that it is mediated by CAM's that differ from those so far identified. 相似文献
84.
Pyrimidine nucleotide synthesis: regulatory control during transformation of lymphocytes in vitro 总被引:9,自引:0,他引:9
Z J Lucas 《Science (New York, N.Y.)》1967,156(779):1237-1240
The incorporation of uridine into RNA in lymphocytes undergoing transformation induced by phytohemagglutinin parallels its incorporation into the intratcellular pool of acid-soluble nucleotides and coincides with a 20-fold increase in the specific activity of uridine kinase. This increase is dependent upon synthesis of both RNA and protein and is subject to both repression and end-product inhibition by cytidine. 相似文献
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86.
Lucas MS 《Science (New York, N.Y.)》1929,70(1820):482-483
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88.
Lucas GB 《Science (New York, N.Y.)》1980,210(4466):147-153
An epidemic of blue mold of tobacco unexpectedly attacked crops in the United States and Canada in 1979, causing an estimated loss of almost a quarter billion dollars. The disease, caused by a fungus, apparently started in Cuba where half the crop was destroyed in 1979 and 90 percent in 1980. Control of blue mold is difficult and expensive. Resistant cultivars become susceptible within a few years. A therapeutic fungicide, metalaxyl, gives efficient control, but resistant strains of the fungus may soon appear. Blue mold is an international problem that will require the collaboration of scientists, governments, and Industries for an adequate solution. 相似文献
89.
Morin S Savarino J Frey MM Yan N Bekki S Bottenheim JW Martins JM 《Science (New York, N.Y.)》2008,322(5902):730-732
Atmospheric nitrogen oxides (NOx =NO+ NO2) play a pivotal role in the cycling of reactive nitrogen (ultimately deposited as nitrate) and the oxidative capacity of the atmosphere. Combined measurements of nitrogen and oxygen stable isotope ratios of nitrate collected in the Arctic atmosphere were used to infer the origin and fate of NOx and nitrate on a seasonal basis. In spring, photochemically driven emissions of reactive nitrogen from the snowpack into the atmosphere make local oxidation of NOx by bromine oxide the major contributor to the nitrate budget. The comprehensive isotopic composition of nitrate provides strong constraints on the relative importance of the key atmospheric oxidants in the present atmosphere, with the potential for extension into the past using ice cores. 相似文献
90.
Armbrust EV Berges JA Bowler C Green BR Martinez D Putnam NH Zhou S Allen AE Apt KE Bechner M Brzezinski MA Chaal BK Chiovitti A Davis AK Demarest MS Detter JC Glavina T Goodstein D Hadi MZ Hellsten U Hildebrand M Jenkins BD Jurka J Kapitonov VV Kröger N Lau WW Lane TW Larimer FW Lippmeier JC Lucas S Medina M Montsant A Obornik M Parker MS Palenik B Pazour GJ Richardson PM Rynearson TA Saito MA Schwartz DC Thamatrakoln K Valentin K Vardi A Wilkerson FP Rokhsar DS 《Science (New York, N.Y.)》2004,306(5693):79-86
Diatoms are unicellular algae with plastids acquired by secondary endosymbiosis. They are responsible for approximately 20% of global carbon fixation. We report the 34 million-base pair draft nuclear genome of the marine diatom Thalassiosira pseudonana and its 129 thousand-base pair plastid and 44 thousand-base pair mitochondrial genomes. Sequence and optical restriction mapping revealed 24 diploid nuclear chromosomes. We identified novel genes for silicic acid transport and formation of silica-based cell walls, high-affinity iron uptake, biosynthetic enzymes for several types of polyunsaturated fatty acids, use of a range of nitrogenous compounds, and a complete urea cycle, all attributes that allow diatoms to prosper in aquatic environments. 相似文献