18 research outputs found

    Loss of susceptibility as a novel breeding strategy for durable and broad-spectrum resistance

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    Recent studies on plant immunity have suggested that a pathogen should suppress induced plant defense in order to infect a plant species, which otherwise would have been a nonhost to the pathogen. For this purpose, pathogens exploit effector molecules to interfere with different layers of plant defense responses. In this review, we summarize the latest findings on plant factors that are activated by pathogen effectors to suppress plant immunity. By looking from a different point of view into host and nonhost resistance, we propose a novel breeding strategy: disabling plant disease susceptibility genes (S-genes) to achieve durable and broad-spectrum resistance

    Estimation of the Pressure Drop Required for Lymph Flow through Initial Lymphatic Networks

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    Background: Lymphatic function is critical for maintaining interstitial fluid balance and is linked to multiple pathological conditions. While smooth muscle contractile mechanisms responsible for fluid flow through collecting lymphatic vessels are well studied, how fluid flows into and through initial lymphatic networks remains poorly understood. The objective of this study was to estimate the pressure difference needed for flow through an intact initial lymphatic network. Methods and Results: Pressure drops were computed for real and theoretical networks with varying branch orders using a segmental Poiseuille flow model. Vessel geometries per branch order were based on measurements from adult Wistar rat mesenteric initial lymphatic networks. For computational predications based on real network geometries and combinations of low or high output velocities (2 mm/s, 4 mm/s) and viscosities (1 cp, 1.5 cp), pressure drops were estimated to range 0.31–2.57 mmHg. The anatomical data for the real networks were also used to create a set of theoretical networks in order to identify possible minimum and maximum pressure drops. The pressure difference range for the theoretical networks was 0.16–3.16 mmHg. Conclusions: The results support the possibility for suction pressures generated from cyclic smooth muscle contractions of upstream collecting lymphatics being sufficient for fluid flow through an initial lymphatic network

    Cell proliferation along vascular islands during microvascular network growth

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    <p>Abstract</p> <p>Background</p> <p>Observations in our laboratory provide evidence of vascular islands, defined as disconnected endothelial cell segments, in the adult microcirculation. The objective of this study was to determine if vascular islands are involved in angiogenesis during microvascular network growth.</p> <p>Results</p> <p>Mesenteric tissues, which allow visualization of entire microvascular networks at a single cell level, were harvested from unstimulated adult male Wistar rats and Wistar rats 3 and 10 days post angiogenesis stimulation by mast cell degranulation with compound 48/80. Tissues were immunolabeled for PECAM and BRDU. Identification of vessel lumens via injection of FITC-dextran confirmed that endothelial cell segments were disconnected from nearby patent networks. Stimulated networks displayed increases in vascular area, length density, and capillary sprouting. On day 3, the percentage of islands with at least one BRDU-positive cell increased compared to the unstimulated level and was equal to the percentage of capillary sprouts with at least one BRDU-positive cell. At day 10, the number of vascular islands per vascular area dramatically decreased compared to unstimulated and day 3 levels.</p> <p>Conclusions</p> <p>These results show that vascular islands have the ability to proliferate and suggest that they are able to incorporate into the microcirculation during the initial stages of microvascular network growth.</p

    Thermal properties of big bluestem as affected by ecotype and planting location along the precipitation gradient of the Great Plains.

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    The objective of this research was to study the effect of ecotype and planting location on thermal properties of big bluestem. Three big bluestem ecotypes (CKS, EKS, ILL) and a cultivar (KAW) were harvested in 2010 from four locations (Colby, Hays, and Manhattan, KS; and Carbondale, IL) and were evaluated for their specific heat, thermal conductivity, thermal stability, HHV (high heating value), and proximate contents. All populations revealed a large variation in specific heat (2.35-2.62 kJ/kg/K), thermal conductivity (77.85-99.06 x 10³ W/m/K), thermogravimetric analysis as weight loss during the heating process (71-73%), and HHV (17.64-18.67 MJ/kg). Specific heat of the big bluestem was significantly affected by planting location, ecotype, and interaction between location and ecotype. Planting location had stronger influence on specific heat than ecotype. Specific heat increased as temperature increased, and a linear correlation model for specific heat prediction was developed as a function of temperature. Ecotype, planting location, and the interaction of ecotype and planting location did not have a significant effect on thermal conductivity; however, density and particle size showed a completely opposite relationship on thermal conductivity. Both planting location and ecotype significantly affected HHV. Among all environmental factors, potential evapotranspiration had the most significant effect on thermal properties
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