Protective effects of ginsenoside Rg1 on intestinal ischemia/reperfusion injury-induced oxidative stress and apoptosis via activation of the Wnt/β-catenin pathway.

Ginsenoside Rg1 (Rg1) is one of the major bioactive ingredients in Panax ginseng, and it attenuates inflammation and apoptosis. The aims of our study were to explore the potential of Rg1 for the treatment of intestinal I/R injury and to determine whether the protective effects of Rg1 were exerted through the Wnt/β-catenin signaling pathway. In this study, Rg1 treatment ameliorated inflammatory factors, ROS and apoptosis that were induced by intestinal I/R injury. Cell viability was increased and cell apoptosis was decreased with Rg1 pretreatment following hypoxia/reoxygenation (H/R) in the in vitro study. Rg1 activated the Wnt/β-catenin signaling pathway in both the in vivo and in vitro models, and in the in vitro study, the activation was blocked by DKK1. Our study provides evidence that pretreatment with Rg1 significantly reduces ROS and apoptosis induced by intestinal I/R injury via activation of the Wnt/β-catenin pathway. Taken together, our results suggest that Rg1 could exert its therapeutic effects on intestinal I/R injury through the Wnt/β-catenin signaling pathway and provide a novel treatment modality for intestinal I/R injury

Responses of forest ecosystems to increasing N deposition in China: A critical review

China has been experiencing a rapid increase in nitrogen (N) deposition due to intensified anthropogenic N emissions since the late 1970s. By synthesizing experimental and observational data taken from literature, we reviewed the responses of China's forests to increasing N deposition over time, with a focus on soil biogeochemical properties and acidification, plant nutrient stoichiometry, understory biodiversity, forest growth, and carbon (C) sequestration. Nitrogen deposition generally increased soil N availability and soil N leaching and decreased soil pH in China's forests. Consequently, microbial biomass C and microbial biomass N were both decreased, especially in subtropical forests. Nitrogen deposition increased the leaf N concentration and phosphorus resorption efficiency, which might induce nutrient imbalances in the forest ecosystems. Although experimental N addition might not affect plant species richness in the overstorey, it did significantly alter species composition of understory plants. Increased N stimulated tree growth in temperate forests, but this effect was weak in subtropical and tropical forests. Soil respiration in temperate forests was non-linearly responsive to N additions, with an increase at dosages of 60 kg N ha(-1) yr(-1). However, it was consistently decreased by increased N inputs in subtropical and tropical forests. In light of future trends in the composition (e.g., reduced N vs. oxidized N) and the loads of N deposition in China, further research on the effects of N deposition on forest ecosystems will have critical implications for the management strategies of China's forests. (C) 2018 Elsevier Ltd. All rights reserved

Patterns and determinants of soil microbial residues from tropical to boreal forests

Soil carbon (C) stabilization has become an important topic in recent years in the context of global climate change. Increasing evidence suggests that microbial residues represent a significant fraction of persistent soil C pools. However, patterns and determinants of soil microbial residues across different biomes remain poorly understood. Here, by combining field investigations from tropical to boreal forests in eastern China with a meta-analysis across global forest biomes, we assessed how biotic and abiotic factors governed the geographic pattern of soil microbial residues indicated by amino sugars. We found that microbial residue concentrations in soils increased significantly from tropical to boreal forests in China and across the globe, which was mainly driven by temperature and soil nitrogen (N). Compared with bacterial residues, fungal residues preferentially accumulated at high latitudes. However, a significant negative relationship existed between soil C/N ratio and total residue-C/SOC in all examined forest soils, indicating a greater contribution of microbial residue-C to SOC in tropical forests than in boreal forests. These findings demonstrate that climate and soil play an important role in microbial-mediated soil C stabilization from boreal to tropical forests

Additional file 1: Table S1. of Low grade astrocytoma transformating primitive neuroectodermal tumour in an adult? A case report and review of literature

Summary of clinical and histological features of cases in the past decade. (DOC 151 kb