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91.
Summary Red algae have the highest known selectivity factor (Srel) for CO2 over O2 of ribulose bisphosphate carboxylase-oxygenase (RUBISCO). This allows the prediction that a red alga relying on diffusive supply of CO2 to RUBISCO from air-equilibrated solution should have less O2 inhibition of photosynthesis than would an otherwise similar non-red alga with a lower Srel of RUBISCO. Furthermore, RUBISCO shows an increased Srel values at low temperatures. The prediction that O 2inhibition of photosynthesis should be small for marine red algae relying on diffusive CO2 entry growing in the North Sea with an annual temperature range of 4–16°C was tested in O2 electrode experiments at 12°C. Phycodrys rubens and Plocamium cartilagineum, which rely on diffusive CO2 entry showed, as predicted, only a small inhibition at lower inorganic C concentrations. Palmaria palmata, which has a CO2 concentrating mechanism, had the expected negligible O 2 inhibition of photosynthesis at any inorganic C concentration except (non-significantly) for saturating inorganic C. 相似文献
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Yoshitaka Uchida Timothy J. Clough Francis M. Kelliher John E. Hunt Robert R. Sherlock 《Plant and Soil》2011,345(1-2):171-186
Grazing ruminants urinate and deposit N onto pastoral soils at rates up to 1,000 kg ha?1, with most of this deposited N present as urea. In urine patches, nitrous oxide (N2O) emissions can increase markedly. Soil derived CO2 fluxes can also increase due to priming effects.While N2O fluxes are affected by temperature, no studies have examined the interaction of pasture plants, urine and temperature on N2O fluxes and the associated CO2 fluxes. We postulated the response of N2O emissions to bovine urine application would be affected by plants and temperature. Dairy cattle urine was collected, labelled with 15N, and applied at 590 kg N ha?1 to a sub-tropical soil,with and without pasture plants at 11°, 19°, and 23°C. Over the experimental period (28 days), 0.2% (11°C with plants) to 2.2% (23°C with plants) of the applied N was emitted as N2O. At 11°C, plants had no effect on cumulative N2O-N fluxes, whereas at 23°C, the presence of plants significantly increased the flux, suggesting plant-derived C supply affected the N2O producing microbes. In contrast, a significant urine application effect on the cumulative CO2 flux was not affected by varying temperature from 11?C23°C or by growing plants in the soil. This study has shown that plants and their responses to temperature affect N2O emissions from ruminant urine deposition. The results have significant implications for forecasting and understanding the effect of elevated soil temperatures on N2O emissions and CO2 fluxes from grazed pasture systems. 相似文献
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Ion Beam Aperture Array Lithography was applied to top-down fabrication of large dense (10(8)-10(9) particles/cm(2)) arrays of uniform micron-scale particles at rates hundreds of times faster than electron beam lithography. In this process, a large array of helium ion beamlets is formed when a stencil mask containing an array of circular openings is illuminated by a broad beam of energetic (5-8 keV) ions, and is used to write arrays of specific repetitive patterns. A commercial 5-micrometer metal mesh was used as a stencil mask; the mesh size was adjusted by shrinking the stencil openings using conformal sputter-deposition of copper. Thermal evaporation from multiple sources was utilized to form magnetic particles of varied size and thickness, including alternating layers of gold and permalloy. Evaporation of permalloy layers in the presence of a magnetic field allowed creation of particles with uniform magnetic properties and pre-determined magnetization direction. The magnetic properties of the resulting particles were characterized by Vibrating Sample Magnetometry. Since the orientation of the particles on the substrate before release into suspension is known, the orientation-dependent magnetic properties of the particles could be determined. 相似文献
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Elissavet Nikolaou Ino Agrafioti Michael Stumpf Janet Quinn Ian Stansfield Alistair JP Brown 《BMC evolutionary biology》2009,9(1):44
Background
Microbes must sense environmental stresses, transduce these signals and mount protective responses to survive in hostile environments. In this study we have tested the hypothesis that fungal stress signalling pathways have evolved rapidly in a niche-specific fashion that is independent of phylogeny. To test this hypothesis we have compared the conservation of stress signalling molecules in diverse fungal species with their stress resistance. These fungi, which include ascomycetes, basidiomycetes and microsporidia, occupy highly divergent niches from saline environments to plant or mammalian hosts. 相似文献99.
Georgia Tsagkogeorga Xavier Turon Russell R Hopcroft Marie-Ka Tilak Tamar Feldstein Noa Shenkar Yossi Loya Dorothée Huchon Emmanuel JP Douzery Frédéric Delsuc 《BMC evolutionary biology》2009,9(1):187-16
Background
Tunicates have been recently revealed to be the closest living relatives of vertebrates. Yet, with more than 2500 described species, details of their evolutionary history are still obscure. From a molecular point of view, tunicate phylogenetic relationships have been mostly studied based on analyses of 18S rRNA sequences, which indicate several major clades at odds with the traditional class-level arrangements. Nonetheless, substantial uncertainty remains about the phylogenetic relationships and taxonomic status of key groups such as the Aplousobranchia, Appendicularia, and Thaliacea. 相似文献100.
GMDD: a database of GMO detection methods 总被引:1,自引:0,他引:1
Wei Dong Litao Yang Kailin Shen Banghyun Kim Gijs A Kleter Hans JP Marvin Rong Guo Wanqi Liang Dabing Zhang 《BMC bioinformatics》2008,9(1):260