Identification of crosstalk genes relating to ECM-receptor interaction genes in MASH and DN using bioinformatics and machine learning.

This study aimed to identify genes shared by metabolic dysfunction-associated fatty liver disease (MASH) and diabetic nephropathy (DN) and the effect of extracellular matrix (ECM) receptor interaction genes on them. Datasets with MASH and DN were downloaded from the Gene Expression Omnibus (GEO) database. Pearson's coefficients assessed the correlation between ECM-receptor interaction genes and cross talk genes. The coexpression network of co-expression pairs (CP) genes was integrated with its protein-protein interaction (PPI) network, and machine learning was employed to identify essential disease-representing genes. Finally, immuno-penetration analysis was performed on the MASH and DN gene datasets using the CIBERSORT algorithm to evaluate the plausibility of these genes in diseases. We found 19 key CP genes. Fos proto-oncogene (FOS), belonging to the IL-17 signalling pathway, showed greater centrality PPI network; Hyaluronan Mediated Motility Receptor (HMMR), belonging to ECM-receptor interaction genes, showed most critical in the co-expression network map of 19 CP genes; Forkhead Box C1 (FOXC1), like FOS, showed a high ability to predict disease in XGBoost analysis. Further immune infiltration showed a clear positive correlation between FOS/FOXC1 and mast cells that secrete IL-17 during inflammation. Combining the results of previous studies, we suggest a FOS/FOXC1/HMMR regulatory axis in MASH and DN may be associated with mast cells in the acting IL-17 signalling pathway. Extracellular HMMR may regulate the IL-17 pathway represented by FOS through the Mitogen-Activated Protein Kinase 1 (ERK) or PI3K-Akt-mTOR pathway. HMMR may serve as a signalling carrier between MASH and DN and could be targeted for therapeutic development.

Mechanism of biochar on nitrification and denitrification to N2O emissions based on isotope characteristic values.

To clarify the mechanism of biochar on nitrification and denitrification to N2O emissions in farmland soil, the effects of combined application of biochar and different nitrogen sources on the contributions of nitrification and denitrification to N2O emissions were studied using isotope characteristic values. The results showed that the soil N2O emissions from ammonium nitrogen fertilizer treatments were significantly higher than that from nitrate nitrogen fertilizer treatments. The biochar combined with ammonium nitrogen fertilizer reduced soil N2O emissions by 31.0%-30.8%, and biochar combined with nitrate nitrogen fertilizer reduced soil N2O emissions by 70.6%-63.0%. The isotope model showed that the application of ammonium nitrogen fertilizer was more favorable for soil nitrification in the early stage of the experiment (0-2 d), and more favorable for denitrification in the middle and later stages of the experiment (3-17 d). Application of nitrate nitrogen fertilizer enhanced the nitrification of soil nitrifying bacteria in the early and middle stages of the experiment (0-8 d), and the denitrification of soil denitrifying bacteria in the later stage of the experiment (9-17 d). The effects of biochar on N2O emissions were mainly in the middle and later stages of the experiment by promoting the nitrification of nitrifying bacteria and inhibiting denitrification of denitrifying bacteria, so as to reduce N2O emission in soil. These results may help to understand the mitigation mechanism of biochar on N2O emission in upland soil.

The contrasting effects of biochar and straw on N2O emissions in the maize season in intensively farmed soil.

This study evaluated the combined effects of biochar and straw on N2O flux and the community compositions of nitrifiers and denitrifiers in the maize season in an intensively farmed area in northern China. The experiment consisted of four treatments: (1) CK (only chemical fertilizer application); (2) C (biochar application); (3) SR (straw application to the field); and (4) C+SR (the application of both biochar and straw). The results indicated that during the maize growing season, N2O flux decreased by 30.3% in the C treatment and increased by 13.2% and 37.0% in the SR and C+SR treatments compared with CK, respectively. NO3--N, NH4+-N, and microbial biomass carbon (MBC) were the main soil factors affecting N2O flux, and they were positively correlated with NO3--N and negatively correlated with MBC in the C treatment and positively correlated with NH4+-N in the SR and C+SR treatments. Both biochar addition and straw return shifted the community compositions of nitrifiers and denitrifiers. N2O production was mainly reduced by promoting the ammonia-oxidizing bacteria (AOB) gene abundance and inhibiting the nirK gene abundance in the C treatment but promoted by inhibiting the AOB and nosZ gene abundances in the SR and C+SR treatments. Nitrosospira (AOB) and Rhizobium (nirK) were the main contributors among the treatments. NO3--N, NH4+-N, and MBC were the main soil factors affecting the denitrifier communities. The predominant species associated with the nirK, nirS, and nosZ genes were positively correlated with NO3--N and MBC and negatively correlated with NH4+-N. These results provide valuable information on the mechanism of N2O production and reduction in biochar- and straw-amended soil under field conditions.

[Effects of Biochar and Straw on Soil N2O Emission from a Wheat Maize Rotation System].

The effects of biochar and straw return on soil N2O emissions were studied in the winter wheat-summer maize rotation system of intensively farmed land in North China to provide a theoretical basis for N2O emission reduction and the efficient straw utilization. The experiment included the following four treatments:① Control (CK); ② Biochar application at a rate of 9.0 t·(hm2·a)-1 (C); ③ Straw return (SR); and ④ Straw return plus biochar application at a rate of 9.0 t·(hm2·a)-1 (C+SR). The results showed that in the wheat season, the CK treatment showed a slight decrease in soil N2O emission while the SR and C+SR treatments promoted soil N2O emission by 47.4% and 71.8%, respectively. In the maize-growing season, the CK treatment reduced soil N2O emission by 29.8% while the SR and C+SR treatments increased soil N2O emission by 13.4% and 35.8%, respectively. During the wheat-growing season, the soil water, NH4+-N, and MBN content were the main environmental factors affecting N2O emissions; during the maize-growing season, NO3--N, NH4+-N, and MBC content were the main environmental factors affecting emissions. Based on our results, the application of biochar to cropland is an effective option for mitigating greenhouse gas emissions, whereas direct straw return to fields might not be an effective strategy. More research is now needed to examine the effect of the return of straw of different maturity on N2O emissions.