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This study evaluated the effects of Inonotus obliquus polysaccharides (IOs) on diabetes and other underlying mechanisms related to inflammatory factors and oxidative stress in a mouse model of streptozotocin (STZ)-induced diabetes. Four weeks administration of metformin (120 mg/kg) and IO1-4 (50%-80% alcohol precipitation), or IO5 (total 80% alcohol precipitation) at doses of 50 mg/kg reverses the abnormal changes of bodyweights and fasting blood glucose levels of diabetic mice. IOs significantly increased the insulin and pyruvate kinase levels in serum, and improved the synthesis of glycogen, especially for IO5. IOs restored the disturbed serum levels of superoxide dismutase, catalase, glutathione peroxidase, and malondialdehyde. The down-regulation of interleukin-2 receptor, matrix metalloproteinase-9, and the enhancement of interleukin-2 in serum of diabetic mice were significantly attenuated by IOs. Histologic and morphology examinations showed that IOs repaired the damage on kidney tissues, inhibited inflammatory infiltrate and extracellular matrix deposit injuries in diabetic mice. Compared with untreated diabetic mice, IOs decreased the expression of phosphor-NF-κB in the kidneys. These results show that IOs treatment attenuated diabetic and renal injure in STZ-induced diabetic mice, possibly through the modulation of oxidative stress and inflammatory factors. These results provide valuable evidences to support the use of I. obliquus as a hypoglycemic functional food and/or medicine.

By exploiting the flexoelectric effect, piezoelectric composites, in which none of the individual components is piezoelectric, can be designed. Here, the flexoelectric piezoelectric composite was designed and fabricated using polyvinylidene fluoride (PVDF). Although the flexoelectric response of PVDF is much lower than that of ferroelectric ceramics, which are normally utilized to fabricate the piezoelectric composites because of their high flexoelectric response, a relatively high apparent piezoelectric response (>11 pC N−1), is obtained in the polymer-based composite because of its low elastic modulus. Our results demonstrate that polymers can be used to fabricate composites with good piezoelectric response and mechanical reliability. [ABSTRACT FROM AUTHOR]

Chemical examination of the green alga Cladophora fascicularis resulted in the isolation and characterization of a new porphyrin derivative, porphyrinolactone (1), along with five known phaeophytins 2-6 and fourteen sterols and cycloartanes. The structure of 1 was determined on the basis of spectroscopic analyses and by comparison of its NMR data with those of known phaeophytins. Compounds 1-6 displayed moderate inhibition of tumor necrosis factor alpha (TNF-α) induced nuclear factor-κB (NF-κB) activation, while 2 and 4 displayed potential inhibitory activity toward proteasome chymotripsin-like activation. The primary structure-activity relationship was also discussed.

We explored the role of light-saturated (carbon-limited) photosynthesis on δ13C of turtlegrass (Thalassia testudinum Banks ex König) populations from the clear, blue waters of the Great Bahama Bank and the turbid, green waters of Florida Bay using field observations and radiative transfer models. Consistent with numerous previous observations, leaf δ13C decreased significantly with water depth in both regions. However the δ13C for Bahamas turtlegrass was 3‰ heavier than that for Florida Bay turtlegrass at equivalent depths, and broadband irradiance explained even less of the δ13C variations than depth. Instead, leaf δ13C showed a stronger relationship to the fraction of the day that photosynthesis of the intact plant canopy was carbon-limited. When the Bahamas and Florida Bay δ13C values were related to the fraction of the day that photosynthesis was carbon-limited, the variations in leaf δ13C observed for Florida and Bahamas populations collapsed into a single relationship that explained 65% of the variation in leaf δ13C. Consequently, turtlegrass from the Bahamas was isotopically heavier than Florida Bay populations growing at equivalent depths because they were more carbon-limited ( = light-saturated) for a larger fraction of the day. The ability to predict turtlegrass δ13C from the daily period of carbon-limited photosynthesis provides a mechanistic link to fundamental relationships between light and photosynthesis that can transcend geographic differences in depth and water-column optical properties, and may permit leaf δ13C to provide a robust indicator of recent photosynthetic performance and plant survival in response to changing environmental conditions. [ABSTRACT FROM AUTHOR]

To assess the impact of ocean acidification on the carbonate chemistry of the shelf waters off the southeastern United States (South Atlantic Bight [SAB]), we measured carbonate mineral saturation states from January 2005 to May 2006. The findings reveal that aragonite (ζ arag: 2.6-4.0) and calcite (ζcal: 4.1-6.0) saturation states were considerably higher than those recently reported along the West Coast of North America. Different water mass age between the Atlantic and Pacific Oceans during global ocean circulation is the primary reason for the higher carbonate mineral saturation states in the SAB than along the West Coast. The contrasting water temperatures in the two coasts contribute to such differences. Both upwelling and freshwater discharge also play important roles in controlling saturation state. Carbonate mineral saturation in the surface water of the West Coast is strongly controlled by the upwelling of high-salinity, low-temperature, low-oxygen, and low-pH deep water. In comparison, saturation states in the surface water of the SAB coast are rarely affected by upwelling. Instead, they are strongly influenced by the input of low-saturation-state water from rivers. Continued increases of atmospheric CO2 under the Intergovernmental Panel on Climate Change B1 emission scenario will decrease the carbonate mineral saturation states by up to 40% by the end of this century, and aragonite will approach undersaturation near the coast. [ABSTRACT FROM AUTHOR]

In this study we estimate sediment carbonate dissolution rates for sandy sea grass sediments on the Bahamas Bank using an inverse pore-water advection/diffusion/reaction model constrained by field observations. This model accounts for sea grass O2 input to these sediments, and also parameterizes pore-water advection through these permeable sediments as a nonlocal exchange process. The resulting rates of carbonate dissolution are positively correlated with sea grass density, and are comparable with previous rate estimates for Florida Bay sediments. In contrast, the advective uptake of O2 by these sediments decreased with increasing sea grass density. This suggests that the competing interplay between bottom-water flow, near-seabed pressure gradients, and the presence of a sea grass canopy is important in controlling this type of sediment oxygen uptake. When the carbonate dissolution rates estimated here are examined in the context of carbonate budgets for shallow-water carbonate platforms systems, they suggest that carbonate dissolution may be a significant loss term in these budgets. Sea grass-mediated carbonate dissolution may also exert a negative feedback on rising atmospheric CO2, although the magnitude of this effect remains to be quantified. [ABSTRACT FROM AUTHOR]

It has been predicted that the Arctic Ocean will sequester much greater amounts of carbon dioxide (CO2) from the atmosphere as a result of sea ice melt and increasing primary productivity. However, this prediction was made on the basis of observations from either highly productive ocean margins or ice-covered basins before the recent major ice retreat. We report here a high-resolution survey of sea-surface CO2 concentration across the Canada Basin, showing a great increase relative to earlier observations. Rapid CO2 invasion from the atmosphere and low biological CO2 drawdown are the main ' causes for the higher CO2, which also acts as a barrier to further CO2 invasion. Contrary to the current view, we predict that the Arctic Ocean basin will not become a large atmospheric CO2 sink under ice-free conditions. [ABSTRACT FROM AUTHOR]