Search

Climate change mitigation and carbon neutrality are current hot topics. Forests, urban green spaces, and wetland ecosystems are recognized as important carbon sinks. The Yangtze River Delta region in Eastern China, which plays a pivotal role in China's economic and social development, is rich in such carbon-sink resources. There is, however, a lack of regional carbon data. The investigation of carbon storage and carbon densities of forest, urban green space, and wetland ecosystems is, therefore, of great importance. In this study, the forest resource management map (including wetland) and green space system planning map of Changzhou city, combined with a field investigation and laboratory experimental analysis, were used to estimate the carbon storages and carbon densities of the forest, urban green space, and wetland ecosystems in Changzhou city. The average carbon density and carbon storage in Changzhou were 83.34 ± 4.91 Mg C ha−1 and 11.30 ± 0.67 Tg C, respectively, of which soil accounted for 74%, plants accounted for 25%, and litter accounted for less than 1%. The forest ecosystem contributed the most to the carbon pool (72%), with the green space ecosystem and the wetland ecosystem each accounting for 14% of the carbon pools. Clearly, the forest, green space, and wetland ecosystems in Changzhou city have a large carbon storage capacity. This study is of significance as it provides data on the carbon sink functions of forest, green space, and wetland ecosystems at the provincial and national regional scales. [ABSTRACT FROM AUTHOR]

With the comprehensive emissions of fossil fuel combustion and transportation waste gas, the concentrations of nitrogen oxides (NOX) in the environmental atmosphere increase significantly, leading to nitric acid rain (NAR) pollution. However, the effects of NAR on soil enzyme activities and soil microbial metabolism are unclear. In this study, the Quercus acutissima Carruth. forest in the Yangtze River Delta of China was selected as the experimental subject, and was exposed to the simulated spraying of NAR with pH values of 2.5, 3.5, and 4.5 to study the response of the forest soil enzyme activities and soil microbial metabolism to NAR. The results showed that compared to the non-NAR treatment, the activities of β-1,4-glucosidase (BG), L-leucine aminopeptidase (LAP), and β-1,4-N-acetylglucosidase (NAG) decreased by 56.48%–42.24%, 44.57%–38.20%, and 56.13%–48.11% under the AR2.5 and AR3.5 treatments, respectively. Moreover, there was no significant change in the Vector Length (VL) under different gradients of NAR. The Vector Angle (VA) increased with the decrease of the pH value and reached the maximum value with the AR2.5 treatment, indicating that the strong acid type NAR had a greater phosphorus-limiting effect on the soil microorganisms. The RDA analysis results showed that the dissolved organic carbon (DOC) was a significant factor affecting the soil enzyme activity and stoichiometric ratio, with interpretation rates of 40.2%. In conclusion, we believe that in the restoration of acidified soil, attention should be paid to the regulation of soil pH, reducing scour. [ABSTRACT FROM AUTHOR]

Soil labile organic carbon sensitively reflects subtle changes in the soil carbon pool and is an important aspect of forest soil carbon pool research. However, little is known regarding soil labile organic carbon storage and its dynamic changes during the development of Quercus acutissima Carruth. forests. Consequently, we investigated the dynamic changes in soil organic carbon and its labile organic carbon fraction stocks at soil depths of 0–10 cm, 10–20 cm, and 20–40 cm along a 17-year-old, 26-year-old, and 65-year-old chronosequence in Quercus acutissima forests. We found that stand age significantly impacted particulate organic carbon (POC), light fraction organic carbon (LFOC), and soil organic carbon (SOC). The POC, LFOC, and SOC contents at different soil depths exhibited an increasing trend with stand age, which could be described by simple linear regression. However, there was no noteworthy difference in the soil water-soluble organic carbon (WSOC) content between different stand ages. Moreover, the 17-year-old, stand had higher POC, LFOC, and WSOC to SOC ratios. Soil nutrients significantly affected organic carbon and fractions, which revealed that POC, LFOC, WSOC, and SOC were remarkably positively correlated with alkaline hydrolysis nitrogen (AN) and available phosphorus (AP) (p < 0.05). Furthermore, WSOC, POC, LFOC, and SOC were significantly positively correlated with available potassium (AK) (p < 0.05). POC, LFOC, and SOC storage in the 0–40 cm soil layer increased with stand development, while WSOC storage decreased at 65a. In addition, LFOC stocks accounted for the highest proportion of organic carbon stocks. Our results indicated that the development of Quercus acutissima forests was a process of carbon sink; however, the soil organic carbon activity was high, and the soil structure was unstable during the early development stage. [ABSTRACT FROM AUTHOR]

• The potential conflict identification of production-living-ecological space uses POI to extract human-oriented factors. • Construct a multi-scale evaluation system integrating suitability and carrying capacity. • The result of incorporating human-oriented factors into the evaluation can more accurately reflect the actual situation. • The urban center area with large proportion of green space also has high ecological suitability. • Spatial conflicts mostly gather at the edge of urban expansion. The rapid urbanization in China has exacerbated the conflicts among production space, living space, and ecological space (PLES). Balancing economic development with ecological protection on limited land resources presents a pivotal challenge in the urbanization process. Mountainous urban agglomerations, with their complex terrain and limited development space, intensify PLES conflicts. Exploring potential PLES conflicts in these areas is crucial for optimizing spatial layout, coordinating human-land relationships, and promoting high-quality regional development. It is also a significant and challenging area in current research. Using the Central Yunnan Urban Agglomeration (CYUA) as a case study, this study integrated grid and administrative scales, incorporating human-oriented factors. A comprehensive evaluation system for mountain urban agglomerations, including suitability evaluation and spatial carrying capacity assessment, had been established. The conflict recognition matrix was used to identify potential PLES conflicts within the urban agglomeration. The results indicated that the PLES in the CYUA predominantly exhibited moderate levels of suitability. Production space suitability was higher in the southeast and lower in the northwest, living space suitability displayed a distinct strip-like distribution. Ecological space suitability was concentrated in the northeast and northwest, with lower suitability observed in the south. Apart from lake areas, approximately 71.92% of land in the CYUA faced potential conflicts regarding land use, primarily general spatial conflicts accounting for 49.79% of the total area. Intense conflict zones covered the smallest area, representing only 0.04% of the study area. The occurrence of potential spatial conflicts in this region was heavily influenced by both natural environmental factors and human activities. Suitable land areas were notably concentrated in regions with high human activity levels, favorable natural environments, and single land use functions. Conflicts were particularly concentrated in transition zones between human production and living spaces and ecological areas. The findings of this study offer valuable insights for guiding urban planning and management strategies not only for the CYUA but also for other mountainous urban agglomerations facing similar challenges. [ABSTRACT FROM AUTHOR]

Cholestasis is caused by intrahepatic retention of excessive toxic bile acids and ultimately results in hepatic failure. Da-Chai-Hu-Tang (DCHT) has been used in China to treat liver and gallbladder diseases for over 1800 years. Here, we demonstrated that DCHT treatment prevented acute intrahepatic cholestasis with liver injury in response to α-naphthylisothiocyanate (ANIT) not to bile duct ligation (BDL) induced-extrahepatic cholestasis. ANIT (80 mg/kg) increased serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), direct bilirubin (DBiL), total bilirubin (TBiL), and total bile acids (TBA) which was attenuated by DCHT treatment in a dose-dependent manner. DCHT treatment at high dose of 1.875 g/kg restored bile acid homeostasis, as evidenced by the recovery of the transcription of genes implicated in bile acid biosynthesis, uptake and efflux. DCHT treatment (1.875 g/kg) reversed ANIT-evoked disordered glutathione homeostasis (as determined by GSH/GSSG ratio) and increased in the mRNA levels for Il6 , Il1b and Tnfa associated with liver inflammation. Using network pharmacology-based approaches, we identified 22 putative targets involved in DCHT treatment for intrahepatic cholestasis not extrahepatic cholestasis. In addition, as evidenced by dual-luciferase reporter assays, compounds from DCHT with high affinity of PPARα increased luciferase levels from a PPARα-driven reporter. PPARα agonist fenofibrate was able to mimic the cytoprotective effect of DCHT on intrahepatic cholestasis, which was abolished by the PPARα antagonist GW6471. KEGG enrichment and western blot analyses showed that signaling axes of JNK/IL-6/NF-κB/STAT3 related to PPARα might be the principal pathway DCHT affects intrahepatic cholestasis. Taken together, the present study provides compelling evidence that DCHT is a promising formula against acute intrahepatic cholestasis with hepatotoxicity which works via PPARα activation. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is an aggressive malignancy with increasing mortality in China. Angiogenesis is crucial for tumor formation, development and metastasis in HCC. Previous studies indicated that high expression levels of elongation factor 2 kinase (eEF2K), a protein kinase that negatively regulates the elongation stage of translation, were associated with poor prognosis of HCC. Here, we show that pharmacological inhibition or knockdown of eEF2K in highly metastatic liver cancer cells inhibits their colony forming and migratory capacities, as well as reducing their invasiveness. Importantly, knocking down eEF2K by lentiviral directed shRNA prevented tumor growth and angiogenesis of HCC in mice. Silencing of eEF2K in endothelial cells (HUVECs) led to a reduction in vascularization, evidenced by a decrease in capillary‐like structures in the matrigel. Notably, knocking down eEF2K reduced the expression of angiogenesis‐related growth factors in liver cancer cells and the expression of growth factor receptors on HUVECs, and thus restricted signaling crosstalk that promotes angiogenesis between HCC cells and endothelial cells. We also showed that silencing of eEF2K effectively reduced protein levels of SP1/KLF5 transcription factors and hence decreased the levels of bound SP1/KLF5 to the VEGF promoter, resulted in a decrease in VEGF mRNA expression. Knocking down eEF2K also led to a striking decrease in the phosphorylation of PI3K/Akt and STAT3, indicating inactivation of these tumorigenic pathways. Taken together, our data suggest that eEF2K contributes to angiogenesis and tumor progression in HCC via SP1/KLF5‐mediated VEGF expression, as well as the subsequent stimulation of PI3K/Akt and STAT3 signaling. What's new? Eukaryotic elongation factor 2 kinase (eEF2K) represses protein synthesis by preventing ribosomes from moving along the mRNA strand. Recent work has associated eEF2K with tumor cell migration and invasion. These authors show how eEF2K promotes angiogenesis and tumor progression in hepatocellular cancer (HCC). Knocking down eEF2K in metastatic liver cancer cells reduced the cells' invasiveness. Cells without eEF2K had less SP1/KLF5 transcription factors, which reduced the amount of VEGF mRNA in the cell. The cells also showed less activity in the PI3K/Akt and STAT pathways. Reducing eEF2K expression in mice, they found, prevented HCC tumor growth and angiogenesis. [ABSTRACT FROM AUTHOR]

The Yellow River Economic Belt (YREB) performs an essential function in the low-carbon development of China as an important ecological protection barrier, and it is of great importance to identify its spatio-temporal heterogeneity and key influencing factors. In this study, we propose a comprehensively empirical framework to conduct this issue. The STIRPAT model was applied to determine the influencing factors of carbon emissions in the YREB from 2006 to 2019. The results show that the carbon emissions in the YREB had significant clustering characteristics in the spatial auto-correlation analysis. In addition, the estimation results of the spatial panel analysis demonstrate that the carbon emissions showed a distinct spatial lag effect and temporal lag effect. Moreover, the three traditional factors including population, affluence, technology are identified as the key influencing factors of carbon emissions in the YREB of China. Furthermore, the spatio-temporal heterogeneity is illustrated vividly by employing the GTWR-STIRPAT model. Finally, policy implications are provided to respond to the demand for low-carbon development.