Insights into fruit function from the proteome of the hypanthium.
ABSTRACT Apple (Malus×domestica Borkh.) was used as a model to studying essential biological processes occurring in mature fruit hypanthium, commonly referred to as the fruit flesh or pulp, a highly active tissue where numerous metabolic processes such as carbohydrate metabolism and signal transduction occur. To understand the complex biological processes occurring in the hypanthium, a proteomics approach was used to analyze the proteome from freshly harvested ripe apple fruits. A total of 290 well-resolved spots were detected using two-dimensional gel electrophoresis (2-DE). Out of these, 216 proteins were identified representing 116 non-redundant proteins using matrix-assisted laser-desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) and either the MASCOT or ProteinProspector engine for peptide mass fingerprinting (PMF) database searching. Identified proteins were classified into 13 major functional categories. Among these, the energy metabolism class was the most represented and included 50% of proteins homologous to Arabidopsis proteins that are involved in the response to biotic and abiotic stresses, suggesting a dual role for these proteins in addition to energy metabolism. We also identified dynein heavy chain in the hypanthium although this protein has been proposed as absent from angiosperms and thus suggest that the lack of dyneins in higher plants studied to date may not be a general characteristic to angiosperm genomic organisation. We therefore conclude that the detection and elucidation of the apple hypanthium proteome is an indispensable step towards the comprehension of fruit metabolism, the integration of genomic, proteomic and metabolomic data to agronomic trait information and thus fruit quality improvements.
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ABSTRACT: Effects of macroscopic residual stresses on fracture toughness of multilayered ceramic laminates were studied analytically and experimentally. Stress intensities for edge cracks in three-layer, single-edge-notch-bend (SENB) specimens with stepwise varying residual stresses in the absence of the crack and superimposed bending were calculated as a function of the crack length by the method of weight function. The selected weight function and the method of calculation were validated by calculating stress intensities for edge cracks in SENB specimens without the residual stresses and obtaining agreement with the stress-intensity equation recommended in ASTM Standard E-399. The stress-intensity calculations for the three-layer laminates with the macroscopic residual stresses were used to define an apparent fracture toughness. The theoretical predictions of the apparent fracture toughness were verified by experiments on three-layer SENB specimens of polycrystalline alumina with 15 vol% of unstabilized zirconia dispersed in the outer layers and 15 vol% of fully stabilized zirconia dispersed in the inner layer. A residual compression of ∼400 MPa developed in the outer layers by the constrained transformation of the unstabilized zirconia from the tetragonal to the monoclinic phase enhanced the apparent fracture toughness to values of 30 MPa.m1/2 in a system where the intrinsic fracture toughness was only 5 to 7 MPa.m1/2.Journal of the American Ceramic Society 01/1996; 79(1):79 - 87. · 2.11 Impact Factor
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ABSTRACT: Alpha-SiAlON ceramics with a refined self-reinforced microstructure, i.e., containing acicular grains with dimensions much smaller than those obtained in previous studies, embedded in a matrix consisting of submicrometer-sized isotropic grains, were prepared by applying a rapid one-step sintering procedure. To suppress the overabundant formation of α-SiAlON nuclei, a combination of stabilizing cations, Y + Yb, was used; to encourage formation of acicular α-SiAlON grains, a small amount of an extra liquid (∼3 vol%) was introduced; to avoid abnormal grain coarsening resulting from dynamic ripening, the final sintering temperature was set to just slightly above the minimum temperature threshold for activating grain growth (1700°C). The fully dense compacts obtained exhibited excellent thermal-shock resistance, and hardness and fracture toughness values of 20 GPa and 5.1 MPa·m1/2, respectively.Journal of the American Ceramic Society 12/2004; 85(11):2876 - 2878. · 2.11 Impact Factor
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ABSTRACT: Tape casting and hot-press sintering are used to fabricate an Al2O3/3Y-TZP laminated composite. The as-prepared material is deep drawn at high temperature to research its superplastic formability. It is found that the microstructure of the material sintered at 1550°C is fine and no significant residual porosity was detected from SEM observations at the interfaces between the two types of layers. The superplastic forming experiment shows that, when the strain rate is constant, temperature has a great influence on the superplasticity of the Al2O3/3Y-TZP laminated composite. A hat-like part with the greatest deform height is obtained at 1500°C. The processing will be less effective at higher or lower temperature.Journal of The European Ceramic Society - J EUR CERAM SOC. 01/2006; 26(3):253-257.