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51.
M K Sykes R N Arnot J Jastrzebski J M Gibbs J Obdrzalek J B Hurtig 《Journal of applied physiology》1975,39(1):103-108
A double-lumen tube was inserted into the trachea of dogs anesthetized with intravenous pentobarbital (30-40 mg/kg). Blood flow/unit lung volume in each lung was measured with 133Xe. Both lungs were initially ventilated with oxygen and measurements of pulmonary blood flow, CO2 output, cardiac output, and blood gases were made. When nitrogen was administered to one lung blood flow was diverted to the opposite lung. The diversion of flow was reduced by the inhalation of 1% trichloroethylene but returned after withdrawal of the anesthetic. There were no significant changes in cardiac output. Changes in CO2 output and arterial Po2 were compatible with the xenon results. It is concluded that trichloroethylene may increase arterial hypoxemia by reducing vasoconstriction in hypoxic areas of lung. 相似文献
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Detection of a β-Lactamase Markedly Active Against Carbenicillin in a Strain of Pseudomonas aeruginosa 下载免费PDF全文
Examination of the substrate profile of a number of beta-lactamases synthesized by strains of Pseudomonas aeruginosa has shown the presence of at least two distinct types of enzyme, one of which is more active against carbenicillin than against benzyl penicillin. 相似文献
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Brian Huntley Judy R. M. Allen Yvonne C. Collingham Thomas Hickler Adrian M. Lister Joy Singarayer Anthony J. Stuart Martin T. Sykes Paul J. Valdes 《PloS one》2013,8(4)
Whereas fossil evidence indicates extensive treeless vegetation and diverse grazing megafauna in Europe and northern Asia during the last glacial, experiments combining vegetation models and climate models have to-date simulated widespread persistence of trees. Resolving this conflict is key to understanding both last glacial ecosystems and extinction of most of the mega-herbivores. Using a dynamic vegetation model (DVM) we explored the implications of the differing climatic conditions generated by a general circulation model (GCM) in “normal” and “hosing” experiments. Whilst the former approximate interstadial conditions, the latter, designed to mimic Heinrich Events, approximate stadial conditions. The “hosing” experiments gave simulated European vegetation much closer in composition to that inferred from fossil evidence than did the “normal” experiments. Given the short duration of interstadials, and the rate at which forest cover expanded during the late-glacial and early Holocene, our results demonstrate the importance of millennial variability in determining the character of last glacial ecosystems. 相似文献
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Knockdown of a laccase in Populus deltoides confers altered cell wall chemistry and increased sugar release 总被引:1,自引:0,他引:1 下载免费PDF全文
Anthony C. Bryan Sara Jawdy Lee Gunter Erica Gjersing Robert Sykes Maud A. W. Hinchee Kimberly A. Winkeler Cassandra M. Collins Nancy Engle Timothy J. Tschaplinski Xiaohan Yang Gerald A. Tuskan Wellington Muchero Jin‐Gui Chen 《Plant biotechnology journal》2016,14(10):2010-2020
Plant laccases are thought to function in the oxidation of monolignols which leads to higher order lignin formation. Only a hand‐full of laccases in plants have been functionally evaluated, and as such little is known about the breadth of their impact on cell wall chemistry or structure. Here, we describe a previously uncharacterized laccase from Populus, encoded by locus Potri.008G064000, whose reduced expression resulted in transgenic Populus trees with changes in syringyl/guaiacyl ratios as well as altered sugar release phenotypes. These phenotypes are consistent with plant biomass exhibiting reduced recalcitrance. Interestingly, the transgene effect on recalcitrance is dependent on a mild pretreatment prior to chemical extraction of sugars. Metabolite profiling suggests the transgene modulates phenolics that are associated with the cell wall structure. We propose that this particular laccase has a range of functions related to oxidation of phenolics and conjugation of flavonoids that interact with lignin in the cell wall. 相似文献
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Jianing Fu Julien Zuber Mercedes Martinez Brittany Shonts Aleksandar Obradovic Hui Wang Sai-ping Lau Amy Xia Elizabeth E. Waffarn Kristjana Frangaj Thomas M. Savage Michael T. Simpson Suxiao Yang Xinzheng V. Guo Michelle Miron Takashi Senda Kortney Rogers Adeeb Rahman Megan Sykes 《Cell Stem Cell》2019,24(2):227-239.e8
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Actin filament dynamics at the cell membrane are important for cell-matrix and cell-cell adhesions and the protrusion of the leading edge. Since actin filaments must be connected to the cell membrane to exert forces but must also detach from the membrane to allow it to move and evolve, the balance between actin filament tethering and detachment at adhesion sites and the leading edge is key for cell shape changes and motility. How this fine tuning is performed in cells remains an open question, but possible candidates are the Drosophila enabled/vasodilator-stimulated phosphoprotein (Ena/VASP) family of proteins, which localize to dynamic actin structures in the cell. Here we study VASP-mediated actin-related proteins 2/3 (Arp2/3) complex-dependent actin dynamics using a substrate that mimics the fluid properties of the cell membrane: an oil-water interface. We show evidence that polymerization activators undergo diffusion and convection on the fluid surface, due to continual attachment and detachment to the actin network. These dynamics are enhanced in the presence of VASP, and we observe cycles of catastrophic detachment of the actin network from the surface, resulting in stop-and-go motion. These results point to a role for VASP in the modulation of filament anchoring, with implications for actin dynamics at cell adhesions and at the leading edge of the cell. 相似文献
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