Maintaining Rice Production while Mitigating Methane and Nitrous Oxide Emissions from Paddy Fields in China: Evaluating Tradeoffs by Using Coupled Agricultural Systems Models

China is the largest rice producing and consuming country in the world, accounting for more than 25% of global production and consumption. Rice cultivation is also one of the main sources of anthropogenic methane (CH4) and nitrous oxide (N2O) emissions. The challenge of maintaining food security while reducing greenhouse gas emissions is an important tradeoff issue for both scientists and policy makers. A systematical evaluation of tradeoffs requires attention across spatial scales and over time in order to characterize the complex interactions across agricultural systems components. We couple three well-known models that capture different key agricultural processes in order to improve the tradeoff analysis. These models are the DNDC biogeochemical model of soil denitrification-decomposition processes, the DSSAT crop growth and development model for decision support and agro-technology analysis, and the regional AEZ crop productivity assessment tool based on agro-ecological analysis. The calibration of eco-physiological parameters and model evaluation used the phenology and management records of 1981-2010 at nine agro-meteorological stations spanning the major rice producing regions of China. The eco-physiological parameters were calibrated with the GLUE optimization algorithms of DSSAT and then converted to the counterparts of DNDC. The upscaling of DNDC was carried out within each cropping zone as classified by AEZ. The emissions of CH4 and N2O associated with rice production under different management scenarios were simulated with the DNDC at each site and also each 1010 km grid-cell across each cropping zone. Our results indicate that it is feasible to maintain rice yields while reducing CH4 and N2O emissions through careful management changes. Our simulations indicated that a reduction of fertilizer applications by 5-35% and the introduction of midseason drainage across the nine study sites resulted in reduced CH4 emission by 17-40% and N2O emission by 12-60%, without negative consequences on rice yield

Acetylbritannilactone Modulates Vascular Endothelial Growth Factor Signaling and Regulates Angiogenesis in Endothelial Cells.

The present study was conducted to determine the effects of 1-O-acetylbritannilactone (ABL), a compound extracted from Inula britannica L., on vascular endothelial growth factor (VEGF) signaling and angiogenesis in endothelial cells (ECs). We showed that ABL promotes VEGF-induced cell proliferation, growth, migration, and tube formation in cultured human ECs. Furthermore, the modulatory effect of ABL on VEGF-induced Akt, MAPK p42/44, and p38 phosphorylation, as well as on upstream VEGFR-2 phosphorylation, were associated with VEGF-dependent Matrigel angiogenesis in vivo. In addition, animals treated with ABL (26 mg/kg/day) recovered blood flow significantly earlier than control animals, suggesting that ABL affects ischemia-mediated angiogenesis and arteriogenesis in vivo. Finally, we demonstrated that ABL strongly reduced the levels of VEGFR-2 on the cell surface, enhanced VEGFR-2 endocytosis, which consistent with inhibited VE-cadherin, a negative regulator of VEGF signaling associated with VEGFR-2 complex formation, but did not alter VE-cadherin or VEGFR-2 expression in ECs. Our results suggest that ABL may serve as a novel therapeutic intervention for various cardiovascular diseases, including chronic ischemia, by regulating VEGF signaling and modulating angiogenesis

Evaluation of division-arrested cells for cell-based high-throughput screening and profiling.

Just-in-time cell supply for cell-based high-throughput screening (HTS) is frequently problematic. In addition to scheduling and logistical issues, quality issues and variability due to passage effect, cell cycle, or confluency contribute to day-to-day signal variability in the course of cell-based HTS campaigns. Cell division-arrest and cryopreservation technologies permit the use of cells as assay-ready reagents for HTS and other cell-based profiling and structure-activity studies. In this report, the authors compare division-arrested and dividing cells in 2 assay types that are dependent on movement of proteins within or through cell membranes: a receptor tyrosine kinase assay involving A431 cells responsive to epidermal growth factor, and a secretion reporter assay, which measures secretion of a reporter gene, secreted alkaline phosphatase. In both assays, dividing and division-arrested cells yielded similar basal and maximal signals at a given cell density. Similar IC50s were obtained for reference inhibitors in each assay, type in both dividing and division-arrested cells. In addition, for the secretion reporter assay, when comparing IC50s obtained from 44 compounds randomly chosen from a primary screening hit list, the rank order of potency obtained from dividing cells and division-arrested cells was essentially identical. Furthermore, the results show that, under certain assay conditions, data generated using division-arrested cells are less variable than those generated using dividing cells. In summary, the results suggest that, in many cases, division-arrested cells can substitute for dividing cells and offer certain advantages for cell-based assays

A spatial-temporal continuous dataset of the transpiration to evapotranspiration ratio in China from 1981–2015

The dataset contains transpiration (T), evapotranspiration (ET), and ratio of transpiration to evapotranspiration (T/ET) from a mode-data fusion method that integrates the Priestly-Taylor Jet Propulsion Laboratory (PT-JPL) model with multivariate observational datasets (transpiration and evapotranspiration). Two temporal resolutions (8-day and annual) are available, with a spatial resolution of 0.05° × 0.05°. T/ET values are unitless for both annual and daily scales, whereas those for transpiration and evapotranspiration have units of mm m-2 day-1 and mm-2 m-2 a-1 for daily and annual scales, respectively. For the annual and daily scale, T/ET values ranged from 0 to 1, and transpiration and evapotranspiration values were greater than zero. The pixels of no data were expressed as -9999. All data were stored in the Network Common Data Form (NetCDF) files. Data files with different temporal resolution were stored in separate directories, i.e., Annual and Daily. The naming convention for each type of data file was similar. For the annual scale, the naming convention is in accordance with the template Annual_VVVV.nc (e.g. Annual T_ET.nc), where VVVV represents the variable name. Each file contains 35 layers, which represent the annual variable for the period ranging from 1981 to 2015. For the daily scale, the naming convention follows the template Daily_VVVV_TTTT.nc (e.g. Daily_T_ET_1981.nc), where VVVV and TTTT represent the variable name and four-digit year. Each file contains 46 layers, and each layer represents the 8-day average evapotranspiration, transpiration, or T/ET

Estimating the grassland aboveground biomass in the Three-River Headwater Region of China using machine learning and Bayesian model averaging

Spatially and temporally explicit information on the biomass in terrestrial ecosystems is essential to better understand the carbon cycle and achieve vegetation resource conservation. As a climate-sensitive critical ecological function area, accurate monitoring of the spatiotemporal variation in the grassland aboveground biomass (AGB) is important in the Three-River Headwater Region (TRHR) of China. In this study, based on field observation, remote sensing, meteorological and topographical data, we estimated the grassland AGB in the TRHR and analyzed its spatiotemporal change and response to climatic factors. Four machine learning (ML) models (random forest (RF), cubist, artificial neural network and support vector machine models) were constructed and compared for AGB simulation purposes. The AGB results estimated with the four ML models were then applied in integrated analysis via Bayesian model averaging (BMA) to obtain more accurate and stable estimates. Our results demonstrated that the RF model performed better among the four ML models (testing dataset: correlation coefficient ( r ) = 0.84; root mean squared error = 76.99 g m ^−2 ), and BMA improved grassland AGB prediction based on the multimodel results. The spatial distribution of the grassland AGB in the TRHR was heterogeneous, with higher values in the southeast and lower values in the northwest. The interannual variation in the grassland AGB in most areas of the TRHR exhibited nonsignificant increasing trends from 2000 to 2018, and the sensitivity of the AGB to the annual precipitation was obviously modulated by regional water conditions. This study provides a more precise method for grassland AGB estimation, and these findings are expected to enable improved assessments to obtain a greater grassland AGB understanding

Effects of ABL on VEGF-induced HUVEC migration and tube formation.

<p>A-B) ABL increases VEGF-induced ECs transwell migration. The data represent the number of migrated cells per microscopic field in VEGF-treated cells vs. control cells. C-D) ABL increases VEGF-induced EC transwell migration. Confluent HUVECs in a monolayer were pretreated with ABL or vehicle for 2 h and wounded with a cell scraper. After 48 h of incubation at 37°C, the number of cells that migrated across the wound edge was counted in each field. E-F) ABL increases VEGF-induced EC tube formation. The images were visualized using a phase contrast microscope (10× magnification). The total tubule length from 10 non-overlapping fields was measured by tracing the tube-like structure. The values represent the mean ± SEM from 3 independent experiments (<i>n</i> = 3). Scale bar: 100 μm.</p

ABL inhibits VE-cadherin and VEGFR-2 complex formation in ECs.

<p>A) Total protein extract from HUVECs pretreated with ABL or vehicle for 2 h, VEGFR-2 immunoprecipitation followed by western blot analysis of VE-cadherin. B-D) Total mRNA was purified from HUVECs pretreated with ABL or vehicle for 2 h, and VE-cadherin (<i>Cdh5</i>) and VEGFR-2 (<i>Vegfr2</i>) mRNA expression were analyzed by quantitative RT-PCR (normalized to <i>Gapdh</i>). ABL did not change VE-cadherin (<i>Cdh5</i>) and VEGFR-2 (<i>Vegfr2</i>) mRNA (B) or protein levels (C-D) in endothelial cells. E-F) Cell surface proteins from ABL-treated HUVECs or vehicle controls were biotinylated, captured on streptavidin Dynabeads, and subjected to Western blotting. The data obtained from 3 independent experiments (<i>n</i> = 3).</p

Schematic representation of the ABL effect on VEGF signaling in ECs.

<p>ABL inhibits VEGFR-2 and VE-cadherin association, thus promoting VEGFR-2 internalization, following by VEGF-induced VEGFR-2 phosphorylation and downstream signaling.</p

ABL enhances VEGF signaling in endothelial cells.

<p>A) HUVECs were serum-starved overnight and pretreated with ABL or vehicle for 2 h, followed by exposure to VEGF-A (50 ng/mL) for various times as indicated. MAPK MAPK p44/42^{Thr202/Tyr204}, p38^{Thr180/Tyr182}, and Akt^Ser473 phosphorylation in the cell lysates were measured via western blot analysis. B-D) The quantitative analysis represents the ratio of phosphorylated/total MAPK MAPK p44/42, MAPK p38, and Akt from 3 independent experiments. E) VEGFR-2^Tyr1175 phosphorylation in the cell lysates was measured via western blot analysis. F) Quantitative analysis of the ratio of phosphorylated/total VEGFR-2 from three independent experiments (<i>n</i> = 3).</p