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Jin-Chun Liu Andries A. Temme William K. Cornwell Richard S. P. van Logtestijn Rien Aerts Johannes H. C. Cornelissen 《Ecological Research》2016,31(2):213-227
Plant responses to carbon (C) and water availability are strongly connected. Thus, we can learn much about the responses of modern plants to rising atmospheric carbon dioxide (CO2) by studying their performance under a range of carbon and water availabilities, including very low CO2 as in past glacial periods. We hypothesized that, especially in shallow soils, the positive effects of high CO2 and the negative effects of low CO2 on growth response to drought are moderated by plant size-driven feedbacks through transpiration and soil water depletion. We grew two temperate annual C3 species, Avena sativa and Chenopodium album, in glacial (180 ppm), modern (400 ppm) and future (700 ppm) CO2 levels and five soil water regimes in climate chambers. In both species, low CO2 resulted in a much lower relative growth rate, biomass and total leaf area than at ambient CO2 with higher water availability, but this difference disappeared steadily towards severe drought conditions. Elevated CO2 increased relative growth rate, plant biomass and total leaf area of both species slightly compared with ambient CO2. These results were especially pronounced under drought. Our results support the hypothesis that, in annuals, plant size modulates the negative drought effect at low CO2. However, plant size-mediated effects of high CO2 on growth response to drought were inconclusive. Further experiments should reveal the interactive effects of CO2 and water regimes in environments closer to a field setting, both in shallow and in deep soils with unconstrained rooting, as well as in mixed communities. 相似文献
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Boot RG Verhoek M Donker-Koopman W Strijland A van Marle J Overkleeft HS Wennekes T Aerts JM 《The Journal of biological chemistry》2007,282(2):1305-1312
The primary catabolic pathway for glucosylceramide is catalyzed by the lysosomal enzyme glucocerebrosidase that is defective in Gaucher disease patients. A distinct non-lysosomal glucosylceramidase has been described but its identity remained enigmatic for years. We here report that the non-lysosomal glucosylceramidase is identical to the earlier described bile acid beta-glucosidase, being beta-glucosidase 2 (GBA2). Expressed GBA2 is identical to the native non-lysosomal glucosylceramidase in various enzymatic features such as substrate specificity and inhibitor sensitivity. Expression of GBA2 coincides with increased non-lysosomal glucosylceramidase activity, and GBA2-targeted RNA interference reduces endogenous non-lysosomal glucosylceramidase activity in cells. GBA2 is found to be located at or close to the cell surface, and its activity is linked to sphingomyelin generation. Hydrophobic deoxynojirimycins are extremely potent inhibitors for GBA2. In mice pharmacological inhibition of GBA2 activity is associated with impaired spermatogenesis, a phenomenon also very recently reported for GBA2 knock-out mice (Yildiz, Y., Matern, H., Thompson, B., Allegood, J. C., Warren, R. L., Ramirez, D. M., Hammer, R. E., Hamra, F. K., Matern, S., and Russell, D. W. (2006) J. Clin. Invest. 116, 2985-2994). In conclusion, GBA2 plays a role in cellular glucosylceramide metabolism. 相似文献
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Nishikawa K Biewener AA Aerts P Ahn AN Chiel HJ Daley MA Daniel TL Full RJ Hale ME Hedrick TL Lappin AK Nichols TR Quinn RD Satterlie RA Szymik B 《Integrative and comparative biology》2007,47(1):16-54
Neuromechanics seeks to understand how muscles, sense organs,motor pattern generators, and brain interact to produce coordinatedmovement, not only in complex terrain but also when confrontedwith unexpected perturbations. Applications of neuromechanicsinclude ameliorating human health problems (including prosthesisdesign and restoration of movement following brain or spinalcord injury), as well as the design, actuation and control ofmobile robots. In animals, coordinated movement emerges fromthe interplay among descending output from the central nervoussystem, sensory input from body and environment, muscle dynamics,and the emergent dynamics of the whole animal. The inevitablecoupling between neural information processing and the emergentmechanical behavior of animals is a central theme of neuromechanics.Fundamentally, motor control involves a series of transformationsof information, from brain and spinal cord to muscles to body,and back to brain. The control problem revolves around the specifictransfer functions that describe each transformation. The transferfunctions depend on the rules of organization and operationthat determine the dynamic behavior of each subsystem (i.e.,central processing, force generation, emergent dynamics, andsensory processing). In this review, we (1) consider the contributionsof muscles, (2) sensory processing, and (3) central networksto motor control, (4) provide examples to illustrate the interplayamong brain, muscles, sense organs and the environment in thecontrol of movement, and (5) describe advances in both roboticsand neuromechanics that have emerged from application of biologicalprinciples in robotic design. Taken together, these studiesdemonstrate that (1) intrinsic properties of muscle contributeto dynamic stability and control of movement, particularly immediatelyafter perturbations; (2) proprioceptive feedback reinforcesthese intrinsic self-stabilizing properties of muscle; (3) controlsystems must contend with inevitable time delays that can simplifyor complicate control; and (4) like most animals under a varietyof circumstances, some robots use a trial and error processto tune central feedforward control to emergent body dynamics. 相似文献
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Novel approaches for the qualitative and quantitative proteomics analysis by nanoscale LC-MS applied to the study of protein expression response in depleted and undepleted serum of Gaucher patients undergoing enzyme replacement therapy are presented. Particular emphasis is given to the method reproducibility of these LC-MS experiments without the use of isotopic labels. The level of chitotriosidase, an established Gaucher biomarker, was assessed by means of an absolute concentration determination technique for alternate scanning LC-MS generated data. Disease associated proteins, including fibrinogens, complement cascade proteins, and members of the high density lipoprotein serum content, were recognized by various clustering methods and sorting and intensity profile grouping of identified peptides. Condition-unique LC-MS protein signatures could be generated utilizing the measured serum protein concentrations and are presented for all investigated conditions. The clustering results of the study were also used as input for gene ontology searches to determine the correlation between the molecular functions of the identified peptides and proteins. 相似文献
19.
Raf Brouns Robert Verkerk Tony Aerts Didier De Surgeloose Annick Wauters Simon Scharpé Peter P. De Deyn 《Neurochemical research》2010,35(9):1315-1322
Post-stroke inflammation may induce upregulation of the kynurenine (KYN) pathway for tryptophan (TRP) oxidation, resulting
in neuroprotective (kynurenic acid, KA) and neurotoxic metabolites (3-hydroxyanthranillic acid, 3-HAA). We investigated whether
activity of the kynurenine pathway in acute ischemic stroke is related to initial stroke severity, long-term stroke outcome
and the ischemia-induced inflammatory response. Plasma concentrations of TRP and its metabolites were measured in 149 stroke
patients at admission, at 24 h, at 72 h and at day 7 after stroke onset. We evaluated the relation between the KYN/TRP ratio,
the KA/3-HAA ratio and stroke severity, outcome and inflammatory parameters (C-reactive protein (CRP), erythrocyte sedimentation
rate (ESR) and neutrophil/lymphocyte ratio (NLR)). KYN/TRP but not KA/3-HAA correlated with the NIHSS score and with the infarct
volume. Patients with poor outcome had higher mean KYN/TRP ratios than patients with more favourable outcome. The KYN/TRP
ratio at admission correlated with CRP levels, ESR and NLR. The activity of the kynurenine pathway for tryptophan degradation
in acute ischemic stroke correlates with stroke severity and long-term stroke outcome. Tryptophan oxidation is related to
the stroke-induced inflammatory response. 相似文献
20.
Sylvia Toet Johannes H. C. Cornelissen Rien Aerts Richard S. P. van Logtestijn Miranda de Beus Rob Stoevelaar 《Plant Ecology》2006,182(1-2):27-40
We studied the effects of elevated CO2 (180–200 ppmv above ambient) on growth and chemistry of three moss species (Sphagnum palustre, S. recurvum and Polytrichum commune) in a lowland peatland in the Netherlands. Thereto, we conducted both a greenhouse experiment with both Sphagnum species and a field experiment with all three species using MiniFACE (Free Air CO2 Enrichment) technology during 3 years. The greenhouse experiment showed that Sphagnum growth was stimulated by elevated CO2 in the short term, but that in the longer term (≥1 year) growth was probably inhibited by low water tables and/or down-regulation
of photosynthesis. In the field experiment, we did not find significant changes in moss abundance in response to elevated
CO2, although CO2 enrichment appeared to reduce S. recurvum abundance. Both Sphagnum species showed stronger responses to spatial variation in hydrology than to increased atmospheric CO2 concentrations. Polytrichum was insensitive to changes in hydrology. Apart from the confounding effects of hydrology, the relative lack of growth response
of the moss species may also have been due to the relatively small increase in assimilated CO2 as achieved by the experimentally added CO2. We calculated that the added CO2 contributed at most 32% to the carbon assimilation of the mosses, while our estimates based on stable C isotope data even
suggest lower contributions for Sphagnum (24–27%). Chemical analyses of the mosses showed only small elevated CO2 effects on living tissue N concentration and C/N ratio of the mosses, but the C/N ratio of Polytrichum was substantially lower than those of the Sphagnum species. Continuing expansion of Polytrichum at the expense of Sphagnum could reduce the C sink function of this lowland Sphagnum peatland, and similar ones elsewhere, as litter decomposition rates would probably be enhanced. Such a reduction in sink
function would be driven mostly by increased atmospheric N deposition, water table regulation for agricultural purposes and
land management to preserve the early successional stage (mowing, tree and shrub removal), since these anthropogenic factors
will probably exert a greater control on competition between Polytrichum and Sphagnum than increased atmospheric CO2 concentrations. 相似文献