Biogeographic Distribution Patterns of Bacteria in Typical Chinese Forest Soils

Microbes are widely distributed in soils and play a very important role in nutrient cycling and ecosystem services. To understand the biogeographic distribution of forest soil bacteria, we collected 115 soil samples in typical forest ecosystems across eastern China to investigate their bacterial community compositions using Illumina MiSeq high throughput sequencing based on 16S rRNA. We obtained 4,667,656 sequences totally and more than 70% of these sequences were classified into five dominant groups, i.e. Actinobacteria, Acidobacteria, Alphaproteobacteria, Verrucomicrobia and Planctomycetes (relative abundance > 5%). The bacterial diversity showed a parabola shape along latitude and the maximum diversity appeared at latitudes between 33.50°N and 40°N, an area characterized by warm-temperate zones and moderate temperature, neutral soil pH and high substrate availability (soil C and N) from dominant deciduous broad-leaved forests. Pairwise dissimilarity matrix in bacterial community composition showed that bacterial community structure had regional similarity and the latitude of 30°N could be used as the dividing line between southern and northern forest soils. Soil properties and climate conditions (MAT and MAP) greatly accounted for the differences in the soil bacterial structure. Among all soil parameters determined, soil pH predominantly affected the diversity and composition of the bacterial community, and soil pH = 5 probably could be used as a threshold below which soil bacterial diversity might decline and soil bacterial community structure might change significantly. Moreover, soil exchangeable cations, especially Ca2+ (ECa2+) and some other soil variables were also closely related to bacterial community structure. The selected environmental variables (21.11%) explained more of the bacterial community variation than geographic distance (15.88%), indicating that the edaphic properties and environmental factors played a more important role than geographic dispersal limitation in determining the bacterial community structure in Chinese forest soils

Spatiotemporal Analysis of AIDS Incidence and Its Influencing Factors on the Chinese Mainland, 2005–2017

Acquired Immune Deficiency Syndrome (AIDS) has become one of the most severe public health issues and nowadays around 38 million people are living with the human immunodeficiency virus (HIV). Ensuring healthy lives and promoting well-being is one of 17 United Nations Sustainable Development Goals. Here, we used the Markov chain matrix and geospatial clustering to comprehensively quantify the trends of the AIDS epidemic at the provincial administrate level in the mainland of China from 2005 to 2017. The Geographically Weighted Regression (GWR) model was further adopted to explore four groups of potential influencing factors (i.e., economy, traffic and transportation, medical care, and education) of the AIDS incidence rate in 2017 and their spatially distributed patterns. Results showed that the AIDS prevalence in southeastern China had been dominant and become prevalent in the past decade. The AIDS intensity level had been increasing between 2008 and 2011 but been gradually decreasing afterward. The analysis of the Markov chain matrix indicated that the AIDS epidemic has been generally in control on the Chinese mainland. The economic development was closely related to the rate of AIDS incidence on the Chinese mainland. The GWR result further suggested that medical care and the education effects on AIDS incidence rate can vary with different regions, but significant conclusions cannot be directly demonstrated. Our findings contribute an analytical framework of understanding AIDS epidemic trends and spatial variability of potential underlying factors throughout a complex extent to customize scientific prevention

A unified geometric rule for designing nanomagnetism in graphene

Based on the underlying graphene lattice symmetry and an itinerant magnetism model on a bipartite lattice, we propose a unifi ed geometric rule for designing graphene-based magnetic nanostructures: spins are parallel (ferromagnetic (FM)) on all zigzag edges which are at angles of 0° and 120° to each other, and antiparallel (antiferromagnetic (AF)) at angles of 60° and 180°. The rule is found to be consistent with all the systems that have been studied so far. Applying the rule, we predict several novel graphene-based magnetic nanostructures: 0-D FM nanodots with the highest possible magnetic moments, 1-D FM nanoribbons, and 2-D magnetic superlattices

Effects of poly-γ-glutamic acid (γ-PGA) on soil nitrogen and carbon leaching and CO2 fluxes in a sandy clay loam soil

Poly-γ-glutamic acid (γ-PGA) showed a significantly promotional-effect on plant production; however, little is known of the environmental footprint generated from the application of γ-PGA. A lab trial was conducted to study the effects of γ-PGA on soil nitrogen and carbon leaching loss and carbon dioxide (CO2) emission by amending 0, 0.0125, 0.025, 0.05, 0.1, 0.2, 0.4, 0.8 g γ-PGA kg-1 soil to the soil receiving 150 kg N ha-1 urea. Results showed that the cumulative loss of ammonium and nitrate decreased by 17.81%-29.31% and 8.27%-52.42% when the application rate of γ-PGA reached 0.1 g kg-1 soil. Cumulative total dissolved nitrogen loss was diminished by 7.16%-40.10% when the γ-PGA application rate was 0.2-0.8 g kg-1 soil. Cumulative loss of dissolved organic carbon was rarely affected by the γ-PGA, while cumulative CO2 flux was notably enhanced by 26.87%-180.70%. Soil total nitrogen (TN) and soil organic carbon (SOC) content varied with the different application rate of γ-PGA, soil TN increased by 6.34%-8.04% and SOC remained unchanged only when the γ-PGA application rate was 0.4-0.8 g kg-1 soil. In conclusion, the environmental protection perspective, not only the perspective of plant production, should be examined before considering the use of γ-PGA in an agroecosystem.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Ectomycorrhizal trees rely on nitrogen resorption less than arbuscular mycorrhizal trees globally

<p>Nitrogen (N) resorption is an important pathway of N conservation, contributing to a proportion of plant N requirement. However, whether the ratio of N resorption to N requirement would be affected by environmental factors, mycorrhizal types or atmospheric CO2 concentration remains unclear. Here, we conducted a meta-analysis on the impacts of environmental factors and mycorrhizal types on this ratio. We found this ratio in ectomycorrhizal (EM) trees decreased with mean annual precipitation (MAP), mean annual temperature (MAT), soil total N content (TN) and atmospheric CO2 concentration and was significantly lower than that in arbuscular mycorrhizal (AM) trees. An <i>in situ</i> 15N tracing experiment further confirmed this stronger reliance on N resorption for AM trees than EM trees. Our study suggests that AM and EM trees potentially have different strategies for alleviation of progressive N limitation, highlighting the necessity of incorporating plant mycorrhizal types into Earth System Models. </p&gt

PGAM5 expression levels in heart failure and protection ROS-induced oxidative stress and ferroptosis by Keap1/Nrf2

Objectives As a common and frequently occurring disease, heart failure has been paid more and more attention, but the mechanism of its occurrence and development is still unclear. This study investigated that PGAM5 expression levels in heart failure and its underlying mechanisms in vivo and in vitro. Methods The inhibition of PGAM5 mRNA expression levels in patients with heart failure was compared with the normal group. Results The serum of PGAM5 mRNA expression was negative correlation with collagen I and collagen III in patients with heart failure. PGAM5 mRNA and protein expression in the heart tissue of mice with heart failure were down-regulated at a time-dependent rate. The inhibition of PGAM5 presented heart failure in the model. PGAM5 reduced inflammation and inhibited ROS-induced oxidative stress in models of heart failure. PGAM5 reduced Ferroptosis in models of heart failure. PGAM5 regulated Keap1/Nrf2 signaling pathway. IP also showed that PGAM5 protein combined with the Keap1 protein. PGAM5 could increase Keap1 protein ubiquitination. Keap1 inhibition affected the effects of PGAM5 in model of heart failure. Conclusions We conclude that the protection of PGAM5 reduced ROS-induced oxidative stress and ferroptosis by the Keap1/Nrf2 signaling pathway in heart failure, suggesting that targeting this mechanism of PGAM5 may be a feasible strategy to treat heart failure

Ectomycorrhizal trees rely on nitrogen resorption less than arbuscular mycorrhizal trees globally

<p>Nitrogen (N) resorption is an important pathway of N conservation, contributing to a proportion of plant N requirement. However, whether the ratio of N resorption to N requirement would be affected by environmental factors, mycorrhizal types or atmospheric CO2 concentration remains unclear. Here, we conducted a meta-analysis on the impacts of environmental factors and mycorrhizal types on this ratio. We found this ratio in ectomycorrhizal (EM) trees decreased with mean annual precipitation (MAP), mean annual temperature (MAT), soil total N content (TN) and atmospheric CO2 concentration and was significantly lower than that in arbuscular mycorrhizal (AM) trees. An <i>in situ</i> 15N tracing experiment further confirmed this stronger reliance on N resorption for AM trees than EM trees. Our study suggests that AM and EM trees potentially have different strategies for alleviation of progressive N limitation, highlighting the necessity of incorporating plant mycorrhizal types into Earth System Models. </p&gt