Untangling the increasing elevation of cropland in China from 1980 to 2020

The redistribution of cropland to areas of higher elevation in China has long affected agricultural development and could seriously threaten national food security.However,there is currently little research reported on this phenomenon,which may limit the improvement of cropland protection policies.To fill this gap,we analyzed the spatiotemporal characteristics and driving mechanisms of increased cropland elevation in China during the period 1980-2020.The average cropland elevation in China increased by 17.38 m from 1980 to 2020.The gravity center of the cropland area and average cropland elevation in China moved to the northwest by 81.00 km and 51.47 km,respectively.The amount of newly added cropland in eastern China was less than that in occupied regions;however,the average elevation of newly added cropland was greater than that of occupied cropland,though the opposite phenomenon was observed in western China.Slope,temperature,land-use intensity,population,economic density,and distance to main roads were the main factors affecting the redistribution of cropland to areas of higher elevation.The effects of these major driving factors exhibited significant spatial and temporal variations in China.This study has important implications for improving existing cropland protection policies and developing more effective cropland management systems in China.

Emerging role of protein modification in inflammatory bowel disease

The onset of inflammatory bowel disease(IBD)involves many factors,including environmental parameters,microorganisms,and the immune system.Although research on IBD continues to expand,the specific pathogenesis mechanism is still unclear.Protein modification refers to chemical modification after protein biosynthesis,also known as post-translational modification(PTM),which causes changes in the properties and functions of proteins.Since proteins can be modified in different ways,such as acetylation,methylation,and phosphorylation,the functions of proteins in different modified states will also be different.Transitions between different states of protein or changes in modification sites can regulate protein properties and functions.Such modifications like neddylation,sumoylation,glycosylation,and acetylation can activate or inhibit various signaling pathways(e.g.,nuclear factor-κB(NF-κB),extracellular signal-regulated kinase(ERK),and protein kinase B(AKT))by changing the intestinal flora,regulating immune cells,modulating the release of cytokines such as interleukin-1β(IL-1β),tumor necrosis factor-α(TNF-α),and interferon-γ(IFN-γ),and ultimately leading to the maintenance of the stability of the intestinal epithelial barrier.In this review,we focus on the current understanding of PTM and describe its regulatory role in the pathogenesis of IBD.