Livestock grazing activities potentially alter ecosystem carbon (C) and nitrogen (N) cycles in grassland ecosystems. Despite the fact that numerous individual studies and a few meta-analyses had been conducted, how grazing, especially its intensity, affects belowground C and N cycling in grasslands remains unclear. In this study, we performed a comprehensive meta-analysis of 115 published studies to examine the responses of 19 variables associated with belowground C and N cycling to livestock grazing in global grasslands. Our results showed that, on average, grazing significantly decreased belowground C and N pools in grassland ecosystems, with the largest decreases in microbial biomass C and N (21.62% and 24.40%, respectively). In contrast, belowground fluxes, including soil respiration, soil net N mineralization and soil N nitrification increased by 4.25%, 34.67% and 25.87%, respectively, in grazed grasslands compared to ungrazed ones. More importantly, grazing intensity significantly affected the magnitude (even direction) of changes in the majority of the assessed belowground C and N pools and fluxes, and C : N ratio as well as soil moisture. Specifically,light grazing contributed to soil C and N sequestration whereas moderate and heavy grazing significantly increased C and N losses. In addition, soil depth, livestock type and climatic conditions influenced the responses of selected variables to livestock grazing to some degree. Our findings highlight the importance of the effects of grazing intensity on belowground C and N cycling, which may need to be incorporated into regional and global models for predicting effects of human disturbance on global grasslands and assessing the climate-biosphere feedbacks.

Curcumin is extensively used as a spice and pigment and has anticarcinogenic effects that could be linked to its antioxidant properties. However, some studies suggest that this natural compound possesses both pro- and antioxidative effects. In this study, we found that curcumin induced DNA damage to both the mitochondrial and nuclear genomes in human hepatoma G2 cells. Using quantitative polymerase chain reaction and immunocytochemistry staining of 8-hydroxydeoxyguanosine, we demonstrated that curcumin induced dose-dependent damage in both the mitochondrial and nuclear genomes and that the mitochondrial damage was more extensive. Nuclear DNA fragments were also evident in comet assays. The mechanism underlies the elevated level of reactive oxygen species and lipid peroxidation generated by curcumin. The lack of DNA damage at low doses suggested that low levels of curcumin does not induce DNA damage and may play an antioxidant role in carcinogenesis. But at high doses, we found that curcumin imposed oxidative stress and damaged DNA. These data reinforce the hypothesis that curcumin plays a conflicting dual role in carcinogenesis. Also, the extensive mitochondrial DNA damage might be an initial event triggering curcumin-induced cell death.

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Biochar has been increasingly recommended for world agriculture, but the effects on microbial activities in agricultural soils has not yet thoroughly assessed. In this study, using a meta-analysis of experiment data retrieved from literature published up to March 1, 2015, changes were examined in microbial biomass and soil respiration in agricultural soils with biochar addition. Microbial responses to biochar addition were quantified in soil respiration quotient (RQ), microbial quotient (MQ) and metabolic quotient (qCO 2) and their differences were evaluated between with and without biochar addition, and among groups of biochar production conditions and experiment conditions. There was an overall increase by 25% in soil microbial biomass carbon (SMBC) and nitrogen (SMBN) but a decrease by 13% in qCO 2 , under biochar compared to the control. Whereas, microbial biomass carbon was increased by 26% but total soil CO 2 production unchanged, across all short term experiments up to 6 months following a single biochar addition. A significant reduction (by <20%) in qCO 2 was found under crop residue and manure biochars in term of feedstock, and biochars pyrolyzed at high temperature over 500℃ in term of pyrolysis temperature. Whereas, the reduction was great (by over 30%) both in clay soils and in neutral soils but moderate (by 15%) in soil organic carbon (SOC) depleted soils, respectively in terms of soil texture, reaction and SOC level. Thus, soil conditions exerted great impacts on microbial metabolic quotient changes compared to biochar conditions. Nevertheless, microbial responses to biochar addition to agricultural soils were much uncertain with respect to both biochar and experiment conditions. Long term field experiments are still deserved to monitor soil microbial processes as long as 3 sustainable soil managements are concerned with biochar technology in agriculture.

Background: Statin has been widely used to treat hyperlipidemia because of its high potency in decreasing cholesterol levels. The present study aimed to examine the lipid-lowering effect of rosuvastatin and the composition, diversity and species abundance of gut microbiome in association with rosuvastatin efficacy. Trial registration: ChiCTR-ORC-17013212 at the First Affiliated Hospital of Dalian Medical University, November 2, 2017.Results: Totally 64 patients with hyperlipidemia were treated with 10 mg/day of rosuvastatin for 4–8 weeks. Blood lipid indicators triglycerides (TG), total cholesterol (TC), high density lipoprotein (HDL), low-density lipoprotein cholesterol (LDL-C) were measured before and after the treatment. Stool samples were collected right after the treatment. Following total DNA extraction and PCR amplification of 16S rRNA gene, Illumina sequencing was performed for gut microbiome identification, classification and characterization. All the patients showed a significant blood lipid reduction after the treatment. The patients were grouped according to parallel manner design. Group I had 33 patients whose blood lipid levels dropped to the normal levels from week 4, with 58.5% reduction in LDL-C and 26.6% reduction in TC. Group II had 31 patients whose blood lipid levels were still above the normal levels after 8 weeks therapy, but with 41.9% reduction in LDL-C and 31.2% reduction in TC. Based on Operational Taxonomic Unit data, Alpha-diversity by Shannon Index was different between the two groups, and beta-diversity by Principle Component Analysis exhibited separated patterns of the two groups. The differences were also observed in the relative-abundance at phylum, family, and genus levels of the two groups. Linear discriminate analysis illustrated that the abundance of 29 taxa was higher in group I, while the abundance of other 13 taxa was higher in group II. Phyla Firmicutes and Fusobacteria had negative correlation to LDL-C level, but Cyanobacteria and Lentisphaerae had a positive correlation to LDL-C level. Moreover, gender and age were also found somehow correlated to microbial community composition.Conclusion: Rosuvastatin therapy had different blood lipid-lowering effect on hyperlipidemia. The gut microbiota exhibited variation in community composition, diversity and taxa in association to rosuvastatin hypolipidemic effect. These results indicate that modulation of gut microflora, especially the negative/positive correlated species might strengthen statin efficacy in statin-inadequate patients.