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Chronic inflammation promotes pancreatic β-cell decompensation to insulin resistance because of local accumulation of supraphysiologic interleukin 1β (IL-1β) levels. However, the underlying molecular mechanisms remain elusive. We show that miR-503-5p is exclusively upregulated in islets from humans with type 2 diabetes and diabetic rodents because of its promoter hypomethylation and increased local IL-1β levels. β-Cell–specific miR-503 transgenic mice display mild or severe diabetes in a time- and expression-dependent manner. By contrast, deletion of the miR-503 cluster protects mice from high-fat diet–induced insulin resistance and glucose intolerance. Mechanistically, miR-503-5p represses c-Jun N-terminal kinase–interacting protein 2 (JIP2) translation to activate mitogen-activated protein kinase signaling cascades, thus inhibiting glucose-stimulated insulin secretion (GSIS) and compensatory β-cell proliferation. In addition, β-cell miR-503-5p is packaged in nanovesicles to dampen insulin signaling transduction in liver and adipose tissues by targeting insulin receptors. Notably, specifically blocking the miR-503 cluster in β-cells effectively remits aging-associated diabetes through recovery of GSIS capacity and insulin sensitivity. Our findings demonstrate that β-cell miR-503-5p is required for the development of insulin resistance and β-cell decompensation, providing a potential therapeutic target against diabetes. Article Highlights: Promoter hypomethylation during natural aging permits miR-503-5p overexpression in islets under inflammation conditions, conserving from rodents to humans. Impaired β-cells release nanovesicular miR-503-5p to accumulate in liver and adipose tissue, leading to their insulin resistance via the miR-503-5p/insulin receptor/phosphorylated AKT axis. Accumulated miR-503-5p in β-cells impairs glucose-stimulated insulin secretion via the JIP2-coordinated mitogen-activated protein kinase signaling cascades. Specific blockage of β-cell miR-503-5p improves β-cell function and glucose tolerance in aging mice. [ABSTRACT FROM AUTHOR]

Identifying saline soils is of great importance for protecting land resources and for the sustainable development of agriculture. Total soil salinity (TSS) is the most commonly used indicator for determining soil salinization, but the application of soil geochemical data is rarely reported. In general, there is a significant relationship between TSS and the content of soil-soluble Na, which can be estimated by the difference between the bulk-soil Na2O content and its background value. In this study, the partial least squares regression (PLSR) method was employed to calculate the Na2O background value via a regression model between Na2O and SiO2, Al2O3, TFe2O3, Cr, Nb, and P in a 1:250,000 scale regional geochemical data set of soils in Jilin Province, NE China. We defined δNa as the difference between the bulk-soil Na2O value and the regression background value, which can be used as a geochemical indicator to identify saline soils. One hundred and five samples with known TSS contents in the study area were selected to test the capability of the indicator δNa. The result shows that the identification accuracy can be up to 75%, indicating that the indicator can provide a new means for saline soil identification. [ABSTRACT FROM AUTHOR]

Abstract: Soil organic carbon changes monitoring is of importance to identify sources or sinks of atmospheric CO2. Multi-period soil organic carbon (SOC) data in Da''an region, Jilin Province in Northeast China, were obtained by National Soil Survey, the National Multi-Purpose Regional Geochemical Survey (NMPRGS) project. Loss or gain of SOC was estimated during 1984–2004. Results show the clear trend of carbon loss from soil to the atmosphere in the period, with a smaller SOC decrease rate in 2004–2008 than the rate in 1984–2004. The NMPRGS project has been carried out since 1999 by collecting topsoil samples (0–20cm) with an average density of one sample per 1km2 and one composite sample per 4km2 for analyses. An area of 1,650,000km2 has been covered by the survey up to 2010 in China. Based on the large amount of SOC data, a new project has been launched to study the loss and gain of soil organic carbon across China, which will provide the basic information to improve the land use management and agricultural operations in the country. [Copyright &y& Elsevier]

A systematic geochemical lake sediment survey has been carried out in major freshwater lakes in China. Surface lake sediment (0–20 cm) at a density of 1 sample/4 km 2 and deep lake sediment (150–180 cm) at a density of 1 sample/16 km 2 were collected and analyzed with standard procedures. This overview provides a current ecological risk assessment for toxic metal contamination (As, Cd, Cr, Cu. Hg, Ni, Pb, and Zn) in the surface sediments of major freshwater lakes in China. Lake sediment in China poses a moderate ecological risk on a nationwide basis using a potential ecological risk index (PERI). Mercury ranked as presenting the greatest ecological risk, followed by Cd, As, Pb, Cu, Ni, Cr, and Zn. Liangzi Lake was classified as having high ecological risk; Dalonghu Lake, Dianchi Lake, Dongting Lake, Fuxian Lake, and Qilu Lake as having moderate ecological risk; while the other surveyed lakes were classified as having low ecological risk. Uncertainties of risk assessment are also discussed by considering geochemical background, the eco-toxicity of metals and the sensitivities of local benthic communities. These comprehensive findings have provided valuable information for improvement of lake management and pollution prevention and control in China. [ABSTRACT FROM AUTHOR]