Characterization of D-fructose transport by rat kidney brush-border membrane vesicles: changes in hypertensive rats

D-fructose transport was characterized in renal brush-border membrane vesicles (BBMVs) from both spontaneously hypertensive rats (SHR) and normotensive genetic control Wistar-Kyoto (WKY) rats. Kinetic studies indicated that the maximal rate (Vmax) of D-fructose transport was significantly lower in SHR compared with WKY rats. No differences were observed in the Michaelis constant (Km) or the diffusion constant (Kd) between the two groups of animals. D-fructose inhibited its own transport, whereas the presence of D-glucose, D-galactose, phlorizin, and cytochalasin B did not inhibit the transport of D-fructose in either animal group. To explain the reduction in D-fructose transport in SHR, the density of the D-fructose transporter, GLUT5, was analyzed by Western blot. GLUT5 levels were lower in SHR, a reduction similar to that of the Vmax. Thus, there appears to be a high-affinity, low-capacity, GLUT5-type fructose carrier in the apical membranes of rat kidney cortex, and the decrease in the Vmax of D-fructose transport in renal BBMVs from hypertensive rats correlates well with a reduction in the expression of GLUT5 protein.     

Tracking apex marine predator movements in a dynamic ocean

Pelagic marine predators face unprecedented challenges and uncertain futures. Overexploitation and climate variability impact the abundance and distribution of top predators in ocean ecosystems. Improved understanding of ecological patterns, evolutionary constraints and ecosystem function is critical for preventing extinctions, loss of biodiversity and disruption of ecosystem services. Recent advances in electronic tagging techniques have provided the capacity to observe the movements and long-distance migrations of animals in relation to ocean processes across a range of ecological scales. Tagging of Pacific Predators, a field programme of the Census of Marine Life, deployed 4,306 tags on 23 species in the North Pacific Ocean, resulting in a tracking data set of unprecedented scale and species diversity that covers 265,386 tracking days from 2000 to 2009. Here we report migration pathways, link ocean features to multispecies hotspots and illustrate niche partitioning within and among congener guilds. Our results indicate that the California Current large marine ecosystem and the North Pacific transition zone attract and retain a diverse assemblage of marine vertebrates. Within the California Current large marine ecosystem, several predator guilds seasonally undertake north-south migrations that may be driven by oceanic processes, species-specific thermal tolerances and shifts in prey distributions. We identify critical habitats across multinational boundaries and show that top predators exploit their environment in predictable ways, providing the foundation for spatial management of large marine ecosystems.     

Morphology and Thermal Behavior of Polypropylene/Easily Hydrodegraded Polyester Blend Fibers

Ultrafine polypropylene fibers are prepared frompolypropylene/easily hydro - degraded polyester (PP/EHDPET) blend fibers, in which file EHDPET compo-nent is degradable by treating with NaOH - H_2O solu-tion. We investigated the morphology of PP/EHDPETblend fibers before and after stretching and alkalinehydrolysis. Then thermal behavior of the blend has alsobeen studied.     

Decreased monosaccharide transport in renal brush-border membrane vesicles of spontaneously hypertensive rats

Na(+)-dependent D-glucose and D-galactose transport were studied in brush-border membrane vesicles (BBMVs) from kidney cortex isolated from both spontaneously hypertensive rats (SHR) and their normotensive genetic control Wistar-Kyoto (WKY) rats. Initial rates and accumulation ratios of Na(+)-dependent D-glucose and D-galactose transport were significantly lower in SHR compared with WKY, the observed decreases being similar for both substrates. To explain the reduction in sugar transport by renal BBMVs, the density of Na(+)-dependent sugar cotransporters was studied in BBMVs from kidney cortex isolated from SHR and WKY rats. Phlorizin-specific binding and Western blot analysis indicated a reduction in the density of the cotransporters in SHR relative to WKY rats. This reduction was similar to those found for the initial rates and accumulation ratios for D-glucose and D-galactose in SHR. Na+ uptake, studied using 22Na+, was significantly increased in SHR, so the observed reduction in sugar transport could be due to disruption of the Na+ gradient between renal BBMVs in SHR. Furthermore, a significant decrease in the activity of Na(+)-K(+)-ATPase was observed in SHR. In conclusion, changes in the density of the Na(+)-dependent sugar cotransporter and in the Na+ gradient across the brush-border membranes might be involved in the observed reduction in sugar transport by renal BBMVs from SHR.