Chemical characterization of a new sulfated polysaccharide from Gracilaria chouae and its activation effects on RAW264.7 macrophages

Preparation of a new resource food-arabinogalactan and its protective effect against enterotoxicity in IEC-6 cells by inhibiting endoplasmic reticulum stress

Plant polysaccharides can be used as bioactive natural polymers that provide health benefits, however high molecular weight neutral polysaccharides have not shown good bioactivity. In this study, high molecular weight neutral arabinogalactan was isolated and structurally characterized to investigate it antioxidant activity against IEC-6 cells. In this study, a neutral polysaccharide (AG-40-I-II) was obtained from the roots of Larix gmelinii (Rupr.) Kuzen. and purified using ethanol fractional precipitation and purification on a DEAE-52 cellulose column and a Superose 12 gel filtration column. The structural characteristics of AG-40-I-II was detected by chemical and spectroscopic methods. The results showed that the average molecular weight of AG-40-I-II was 18.6 kDa, the main chain was composed of →4)-β-D-Gal-(1, → 4, 6)-β-D-Gal-(1 and →4)-β- D-Glc-(1, the side chain is composed of T-β-L-Araf(1 → 6). The effect of AG-40-I-II on H2O2-induced IEC-6 cell injury was determined by MTT method. Besides, AG-40-I-II could reduce the level of MDA and increase SOD activity on IEC-6 cells, which could significantly inhibit the production of ROS. Importantly, AG-40-I-II inhibited the splicing of XBP1 by IRE1α through the ERS pathway and reduced the cell apoptosis induced by H2O2. In summary, the results of this study indicate that AG-40-I-II, as a natural source of plant polysaccharides, has good antioxidant activity, and is expected to become a safe plant source of natural antioxidants, which has great potential in biomedicine potential.

Multi-Scenario Simulation of Ecosystem Service Values in the Guanzhong Plain Urban Agglomeration, China

Rapid urbanization and human activities enhanced threats to the degradation of various ecosystem services in modern urban agglomerations. This study explored the response of ecosystem service values (ESVs) to land use changes and the trade-offs among various ESVs in urban agglomerations under different future development scenarios. The patch-general land use simulation (PLUS) model and ESV calculation method were used to simulate the ESVs of Guanzhong Plain Urban Agglomeration under the Business As Usual scenario (BAU), Ecological Conservation scenario (EC), and Economic Development scenario (ED) in 2030. Global and local Moran’s I were used to detect the spatial distribution pattern, and correlation analysis was used to measure trade-offs among ecosystem services. The results showed that: (1) The simulated result of land use in Guanzhong Plain Urban Agglomeration showed high accuracy compared to the actual observed result of the same period, with a Kappa coefficient of 0.912. From 2000 to 2030, land use changes were significant, with the rapid decrease in farmland and an increase in construction land. The area of woodland increased significantly under the EC scenario, and the area of construction land increased rapidly under the ED scenario. (2) The decline of total ESV was CNY 218 million from 2000 to 2020, and ESVs remained the downward trend in the BAU and ED scenarios compared to 2020, decreasing by CNY 156 million and CNY 4731 million, respectively. An increasing trend of ESV showed under the EC scenario, with a growth of CNY 849 million. (3) Significant spatial autocorrelation showed in Guanzhong Plain Urban Agglomeration, as the Global Moran’s I were all positive and the p-values were zero. The ESV grids mainly showed “High-High” clusters in the mountainous areas and “Low-Low” clusters in plain areas. Except for food production, a majority of ecosystem services exhibited positive synergistic relationships. In future planning and development, policymakers should focus on the coordinated development of the urbanization process and ecological preservation to build an ecological safety pattern.

Conflict Identification and Zoning Optimization of “Production-Living-Ecological” Space

With the acceleration of economic and social development and the increasing competition between multi-functional spaces, the coordination and stability of land space have been seriously affected. In order to simulate the conflict pattern of “production, living ecological” space and analyze its evolution characteristics, taking Qianjiang City as the research area and based on the current data of land use, the FLUS (Future Land Use Simulation) model and spatial conflict measurement model are used to calculate the change trend of “production, living ecological” spatial conflict in Qianjiang City in the past and in the future. The research results are of great significance for the scientific use of land space and the optimization of regional development patterns. The results show that: (1) From 2000 to 2020, the level of spatial conflict in Qianjiang City showed an upward trend, the proportion of medium and above conflict units gradually increased, and the conflict level in the study area gradually became dominated by strong conflict. (2) Due to the process of urbanization and the continuous growth of population and GDP (Gross Domestic Product), the construction land in Qianjiang City shows a rapid increase trend under three scenarios, and the cultivated land area shows a downward trend. (3) In 2035, under the three scenarios, the spatial conflict in Qianjiang City will be strengthened, mainly at the level of medium and above. (4) According to the change degree of conflict transformation, 15 change types are divided into five functional zones: ecological protection zone, ecological conservation zone, modern agriculture zone, urban–rural development coordination zone and urban optimization zone.

Assessment of Land Use Pattern and Landscape Ecological Risk in the Chengdu-Chongqing Economic Circle, Southwestern China

The Chengdu-Chongqing Economic Circle (CCEC) is becoming the fourth growth pole in China after the Yangtze River Delta Economic Circle (YRDEC); Guangdong, Hong Kong, and Macao Economic Circle (GBAEC); Beijing, Tianjin, and Hebei Economic Circle (BTHEC). The land use and landscape ecological management of the CCEC is critical to its social and economic development. Using ArcGIS modeling and Fragstats processing methods, we divided the CCEC into 5 km × 5 km ecological risk areas and constructed a landscape ecological risk index evaluation model to calculate the spatial and temporal dynamic changes in the urban expansion and landscape ecological risk over the last 20 years. The results show that the land use was mainly cultivated land, which exhibited a decreasing trend and was mainly converted to construction land and forest land. The change in the construction land exhibited a continuous expansion trend with the dual core in Chengdu-Chongqing. The average risk of 10,155 risk communities was about 0.16. The expansion of human activities increased the landscape ecological risk of the construction land, and the risk of the edge of the cultivated land was higher than the internal risk value. The ecological risk index values of 16 cities in the study area ranged from 0.02 to 0.28. The resistance of the landscape pattern to external disturbance was stronger than that in other regions of China. The landscape ecological risk is controllable overall. However, the higher level of economic development in Chengdu, Chongqing, and other mature cities poses a greater landscape ecological risk. The results of this research provide an important reference for promoting the optimization and construction of the land space in the CCEC, building ecological shelters, and preventing ecological risk in the upper reaches of the Yangtze River.