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IntroductionSoil microbes are central in governing soil multifunctionality and driving ecological processes. Despite biochar application has been reported to enhance soil biodiversity, its impacts on soil multifunctionality and the relationships between soil taxonomic biodiversity and ecosystem functioning remain controversial in paddy soil.MethodsHerein, we characterized the biodiversity information on soil communities, including bacteria, fungi, protists, and nematodes, and tested their effects on twelve ecosystem metrics (including functions related to enzyme activities, nutrient provisioning, and element cycling) in biochar-amended paddy soil.ResultsThe biochar amendment augmented soil multifunctionality by 20.1 and 35.7% in the early stage, while the effects were diminished in the late stage. Moreover, the soil microbial diversity and core modules were significantly correlated with soil multifunctionality.DiscussionOur analysis revealed that not just soil microbial diversity, but specifically the biodiversity within the identified microbial modules, had a more pronounced impact on ecosystem functions. These modules, comprising diverse microbial taxa, especially protists, played key roles in driving ecosystem functioning in biochar-amended paddy soils. This highlights the importance of understanding the structure and interactions within microbial communities to fully comprehend the impact of biochar on soil ecosystem functioning in the agricultural ecosystem.

IntroductionAmmonia oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB) have been proven to be key microorganisms driving the ammonia oxidation process. However, under different fertilization practices, there is a lack of research on the impact of interaction between predators and AOA or AOB on nitrogen cycling at the multi-trophic level.MethodsIn this study, a network-oriented microscopic culture experiment was established based on four different long-term fertilization practices soils. We used the nitrification inhibitors 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxide-3-oxyl (PTIO) and 3, 4-Dimethylpyrazole phosphate (DMPP) inhibited AOA and AOB, respectively, to explore the impact of interaction between protists and AOA or AOB on nitrogen transformation.ResultsThe results showed that long-term nitrogen application promoted the potential nitrification rate (PNR) and nitrous oxide (N2O) emission, and significantly increased the gene abundance of AOB, but had no obvious effect on AOA gene abundance. DMPP significantly reduced N2O emission and PNR, while PTIO had no obvious effect on them. Accordingly, in the multi-trophic microbial network, Cercozoa and Proteobacteria were identified as keystone taxa of protists and AOB, respectively, and were significantly positively correlated with N2O, PNR and nitrate nitrogen. However, Nitrososphaerota archaeon as the keystone species of AOA, had an obvious negative linkage to these indicators. The structural equation model (SEM) showed that AOA and AOB may be competitors to each other. Protists may promote AOB diversity through direct trophic interaction with AOA.ConclusionThe interaction pattern between protists and ammonia-oxidizing microorganisms significantly affects potential nitrification rate and N2O emission, which has important implications for soil nitrogen cycle.

Stable soil organic carbon (SOC) formation in coastal saline soils is important to improve arable land quality and mitigate greenhouse gas emissions. However, how microbial life-history strategies and metabolic traits regulate SOC turnover in coastal saline soils remains unknown. Here, we investigated the effects of microbial life history strategy tradeoffs on microbial carbon use efficiency (CUE) and microbial-derived SOC formation using metagenomic sequencing technology in different salinity soils. The results showed that high-salinity is detrimental to microbial CUE and microbial-derived SOC formation. Moreover, the regulation of nutrients stoichiometry could not mitigate adverse effects of salt stress on microbial CUE, which indicated that microbial-derived SOC formation is independent of stoichiometry in high-salinity soil. Low-salinity soil is dominated by a high growth yield (Y) strategy, such as higher microbial biomass carbon and metabolic traits which are related to amino acid metabolism, carbohydrate metabolism, and cell processes. However, high-salinity soil is dominated by stress tolerance (S) (e.g., higher metabolic functions of homologous recombination, base excision repair, biofilm formation, extracellular polysaccharide biosynthesis, and osmolytes production) and resource acquisition (A) strategies (e.g., higher alkaline phosphatase activity, transporters, and flagellar assembly). These trade-offs of strategies implied that resource reallocation took place. The high-salinity soil microbes diverted investments away from growth yield to microbial survival and resource capture, thereby decreasing biomass turnover efficiency and impeding microbial-derived SOC formation. Moreover, altering the stoichiometry in low-salinity soil caused more investment in the A-strategy, such as the production of more β-glucosidase and β-N-acetyl-glucosaminidase, and increasing bacterial chemotaxis, which thereby reduced microbial-derived SOC formation. Our research reveals that shift the microbial community from S- and A- strategies to the Y-strategy is important to increase the microbial CUE, and thus enhance SOC turnover in coastal saline soils.

IntroductionThe ecological environment of tidal flats often changes due to tidal erosion and sedimentation. The distribution of tidal flat surface sediment is a natural reflection of the changes in the external dynamic environment, the spatial and temporal distribution pattern is of great significance.MethodsIn this study, the output structure of traditional convolutional neural network is combined with BP neural network. Meanwhile, four phases of Sentinel-2 multispectral images were collected and combined with field data from the Doulonggang tidal flat in Jiangsu Province, China, to construct the sediment composition inversion model.ResultsThe inversion accuracy was higher than 80% compared with the measured results. According to the inversion result, from 2017 to 2022, the surface sediment particle size of the tidal flat in Jiangsu varied seasonally and was coarse in summer and fine in winter. Additionally, the sediment composition tended to coarsen, showing an interannual change trend of increasing sand content and decreasing clay and silt contents.DiscussionThe above change of the sedimentary environment of the tidal flat may be caused by the decrease of fine grained sediment deposition, the introduction of exotic vegetation, the global sea level rise and the influence of human activities.

Soil microbial use efficiency of straw carbon (C), which is the proportion of straw-C microbes assimilate into new biosynthetic material relative to C lost out of the system as CO2, is critical in increasing soil organic C (SOC) content, and hence maintaining soil fertility and productivity. However, the effect of chemical structures of the organic amendments (OAs) on the microbial use efficiency of straw-C remains unclear. The effect of the chemical structure of the OAs on microbial use efficiency of straw-C was elucidated by a combination of 13C-straw labeling with high-throughput sequencing and pyrolysis-GC/MS. We found a strong positive correlation between the microbial use efficiency of straw-C and the proportion of heterocyclic compounds (Hete_C). The microbial use efficiency of straw-C was highest in soil supplemented with Hete_C-dominant OAs, which significantly shifted microbial community structure toward fungal dominance. Specifically, fungal-to-bacterial ratio, fungal richness, and the relative abundance of Ascomycota were higher in soil with a higher proportion of Hete_C-dominant OAs. Together, our study suggests that OAs with high proportion of Hete_C promote the microbial use efficiency of straw-C by increasing the dominance of fungi in the soil microbial community in agroecosystems.

Efficient gas extraction technology is an important topic for low permeability and high gas outburst coal seam. Based on the engineering background of Hudi Coal Mine with the soft and hard coal seams and the existing hydraulic permeability enhancement technology, a new construction process to improve coal seam permeability was proposed to effectively reduce coal seam gas content and the risk of coal and gas outburst. In this measure, the roadway in floor was replaced with a directional main borehole, directional branch boreholes were used to replace crossing holes, and soft coal was mined along soft sub layers via the directional drilling machine and directional hydraulic jet. Main boreholes are drilled parallel to the seam in the coal seam floor, and branch boreholes are drilled through the floor and coal seam. The numerical simulation was used to study the permeability improvement effect of different mining diameters by the proposed measure. The result showed that, as the mining diameter increased from 2 m to 4 m, the average influence diameter of coal seam porosity increased from 15.44 m to 19.65 m, and the average influence diameter of the permeability increased from 15.75 m to 20.07 m, which is three times the influence range of the ordinary borehole. The application of the proposed measure and its supporting equipment was carried out under the special coal seam and gas conditions of Hudi Coal Mine. Results show that the soft coal was mined efficiently along the soft sub layer using the main borehole, branch boreholes, and directional hydraulic jet. Compared the traditional hydraulic flushing in the borehole with the ordinary drilling machine, the average speed of mining soft sub layers increased from 0.5 t/h to 3.6 t/h, the equivalent mining diameter of soft sub layers increased from 1.2 m to 7.6 m, and the average flow of gas extraction increased from 0.41 m3/d to 6.25 m3/d. The conclusions obtained in this study can provide a reference for coal mine gas extraction with similar coal seam conditions.

Background: Chronic neck pain (CNP) is highly prevalent and complicated, associated with limited movement, and accompanied by shoulder pain and other clinical manifestations such as dizziness, anxiety, and insomnia. Brain structural and functional abnormalities often occur in patients with CNP. However, knowledge of the brain’s functional organization and temporal dynamics in CNP patients is limited. Dynamic functional connectivity density (dFCD) can reflect the ability of brain areas or voxels to integrate information, and could become neuroimaging markers for objectively reflecting pain to a certain extent. Therefore, this study compared the dFCD between CNP patients and healthy controls (HCs) and investigated potential associations of the abnormal density variability in dynamic functional connectivity with pain characteristics in CNP patients.Methods: Resting functional magnetic resonance imaging was performed for 89 CNP patients and 57 HCs. After preprocessing resting-state fMRI images by the Data Processing and Analysis of Brain Imaging toolbox, the sliding window method was applied to investigate dFCD changes in CNP patients and HCs using the DynamicBC toolbox. Then we quantified dFCD variability using their standard deviation. Based on the pain-associated factors collected from the case report form of CNP patients, the mean dFCD variability values of each dFCD from region of interest were extracted to calculate Pearson’s correlation coefficient to study the potential correlation between dFCD abnormal variability and pain.Results: Compared with HCs, the dFCD values of the anterior cingulate cortex, occipital lobe, temporal lobe, and cerebellum were statistically different in patients with CNP. Subsequent correlation analysis showed that the variable dFCD in the related brain region was correlative with the course of the disease and clinical symptoms, such as pain and depression, in patients with CNP.Conclusion: Dynamic functional alterations were observed in the brain regions of CNP patients, and the dFCD of these brain regions could become neuroimaging markers for objectively reflecting pain to a certain extent. This suggests that chronic pain may cause changes in pain processing and emotional feedback and highlights the link between dynamic neural communication in brain regions and disease conditions, deepening our understanding of chronic pain diseases, and guiding clinical practice.

Tributyltin oxide (TBTO), an organotin compound, has been demonstrated to have toxic effects on several cell types. Previous research has shown that TBTO impairs mouse denuded oocyte maturation. However, limited information is available on the effects of TBTO exposure on livestock reproductive systems, especially on porcine oocytes in the presence of dense cumulus cells. In the present research, we evaluated the effects of TBTO exposure on porcine oocyte maturation and the possible underlying mechanisms. Porcine cumulus-oocyte complexes were cultured in maturation medium with or without TBTO for 42 h. We found that TBTO exposure during oocyte maturation prevented polar body extrusion, inhibited cumulus expansion and impaired subsequent blastocyst formation after parthenogenetic activation. Further analysis revealed that TBTO exposure not only induced intracellular reactive oxygen species (ROS) accumulation but also caused a loss of mitochondrial membrane potential and reduced intracellular ATP generation. In addition, TBTO exposure impaired porcine oocyte quality by disrupting cellular iron homeostasis. Taken together, these results demonstrate that TBTO exposure impairs the porcine oocyte maturation process by inducing intracellular ROS accumulation, causing mitochondrial dysfunction, and disrupting cellular iron homeostasis, thus decreasing the quality and impairing the subsequent embryonic developmental competence of porcine oocytes.

Accumulating evidence indicates that ferroptosis is an iron-dependent form of regulated cell death. This type of iron-dependent programmed cell death is different from traditional forms of regulated cell death, such as apoptosis and autophagy. However, the role of ferroptosis in porcine oocyte maturation and the associated mechanism remain unclear. In the present research, we investigated the effects of ferric ammonium citrate (FAC), a specific ferroptosis inducer, on porcine oocyte meiotic maturation and quality and subsequent embryonic developmental competence. FAC treatment caused obvious accumulation of intracellular ferrous ions in porcine oocytes. At the end of the in vitro maturation (IVM) period, there was a significant decrease in the polar body (PB) extrusion rate and an increase in the percentage of abnormal oocytes in the FAC treatment groups, indicating that iron overload-induced ferroptosis may suppress the meiotic process during porcine oocyte maturation. We also found that after FAC treatment, the subsequent two-cell rate, four-cell rate and blastocyst formation rate were significantly decreased in porcine parthenogenetic activation (PA) embryos, indicating that iron overload-induced ferroptosis decreased porcine oocyte quality. Further analysis revealed that FAC treatment not only enhanced intracellular reactive oxygen species (ROS) generation, decreased intracellular free thiol levels and induced mitochondrial dysfunction but also triggered autophagy in porcine oocytes. Taken together, these findings suggest that iron overload-induced ferroptosis impairs porcine oocyte meiosis and decreases porcine oocyte quality, possibly by increasing oxidative stress, inducing mitochondrial dysfunction and triggering autophagy.

The human brain shows neuroplastic adaptations caused by motor skill training. Of note, there is little known about the plastic architecture of the whole-brain network in resting state. The purpose of the present study was to detect how motor training affected the density distribution of whole-brain resting-state functional connectivity (FC). Resting-state functional magnetic resonance imaging data was assessed based on a comparison of fast-ball student athletes (SA) and non-athlete healthy controls (NC). The voxel-wise data-driven graph theory approach, global functional connectivity density (gFCD) mapping, was applied. Results showed that the SA group exhibited significantly decreased gFCD in brain regions centered at the left triangular part of the inferior frontal gyrus (IFG), extending to the opercular part of the left IFG and middle frontal gyrus compared to the NC group. In addition, findings suggested the idea of an increased neural efficiency of athletes’ brain regions associated with attentional–motor modulation and executive control. Furthermore, behavioral results showed that in the SA group, faster executive control reaction time relates to smaller gFCD values in the left IFG. These findings suggested that the motor training would decrease the numbers of FC in IFG to accelerate the executive control with high attentional demands and enable SA to rapidly focus the attention to detect the intriguing target.

The effects of land use and fertilization regimes on soil denitrification potential (SDP) are often investigated, but less is known about the responses of SDP to different types of land use with different fertilization regimes in soils derived from the same parent material. We conducted a study using soil samples from 2 long-term (over 30 years) fertilization experiments to determine the difference in SDP between paddy soil and upland soil derived from the same quaternary red clay parent material. The results showed that the SDP in paddy soil was 6.82 times higher than the upland soil, which was due to the higher abundances of narG, nirS, and nirK genes and nirS-denitrifying bacteria (Bradyrhizobium, Cupriavidus, and Herbaspirillum) in paddy soil. Inorganic fertilization regimes did not significantly affect the SDP of upland soil over the control group, whereas SDP in the NPK and 2NPK treatments in paddy soil were reduced relative the control group by 26.48% and 75.65%, respectively. Compared with the control, the NPKOM treatment consistently yielded the highest SDP in both soils, with 2.47 times and 2.86 times higher for paddy soil and upland soil, respectively. The SDP of paddy soil was significantly correlated with narG and nirS genes mainly regulated by amorphous aluminum oxide, whereas the treatment effect on SDP for upland soil largely depended on differences in nirS-denitrifying bacteria at the genus level (Herbaspirillum, Sulfuritalea, and Cupriavidus) and species level, which were mainly controlled by soil pH. Partial least squares path models further demonstrated that the direct effects of functional genes on SDP were greatest for paddy soil, whereas nirS-denitrifying bacterial communities played a larger role in upland soil. The results presented herein represent a key step toward understanding the mechanisms that govern SDP under land use and long-term fertilization.

Potassium (K) distribution is horizontally heterogeneous under the conservation agriculture approach of no-till with strip fertilization. The root foraging strategy of wheat for K heterogeneity is poorly understood. In this study, WinRHIZO, microarray, Non-invasive Micro-test Technology (NMT) and a split-root system were performed to investigate root morphology, gene expression profiling and fluxes of K+ and O2 under K heterogeneity and homogeneity conditions. The split-root system was performed as follows: C. LK (both compartments had low K), C. NK (both compartments had normal K), Sp. LK (one compartment had low K) and Sp. NK (the other compartment had normal K). The ratio of total root length and root tips in Sp. NK was significantly higher than that in C. NK, while no significant differences were found between Sp. LK and C. LK. Differential expression genes in C. LK vs. C. NK had opposite responses in Sp. LK vs. C. LK and similar responses in Sp. NK vs. C. NK. Low-K responsive genes, such as peroxidases, mitochondrion, transcription factor activity, calcium ion binding, glutathione transferase and cellular respiration genes were found to be up-regulated in Sp. NK. However, methyltransferase activity, protein amino acid phosphorylation, potassium ion transport, and protein kinase activity genes were found to be down-regulated in Sp. LK. The up-regulated gene with function in respiration tended to increase K+ uptake through improving O2 influx on the root surface in Sp. NK, while the down-regulated genes with functions of K+ and O2 transport tended to reduce K+ uptake on the root surface in Sp. LK. To summarize, wheat roots tended to perform active-foraging strategies in Sp. NK and dormant-foraging strategies in Sp. LK through the following patterns: (1) root development in Sp. NK but not in Sp. LK; (2) low-K responsive genes, such as peroxidases, mitochondrion, transcription factor activity, calcium ion binding and respiration, were up-regulated in Sp. NK but not in Sp. LK; and (3) root K+ and O2 influxes increased in Sp. NK but not in Sp. LK. Our findings may better explain the optimal root foraging strategy for wheat grown with heterogeneous K distribution in the root zone.

Although increasing evidences have emerged for responses of soil microorganisms to fertilizations, the knowledge regarding community assemblages that cause variations in composition is still lacking, as well as the possible feedback to soil fertility. Phylogenetic conservatism of species indicates their similar environmental preferences and/or function traits and phylogenetic signals further can infer community assemblages and influenced ecological processes. Here, we calculated the mean pairwise phylogenetic distance and nearest relative index, characterizing phylogenetic signal and the undergone ecological process to evaluate the community assembly of soil bacterial phylotypes in 20-year fertilized soils. The bacterial community assembly is structured by environmental filtering, regardless of fertilization regime. Soil phosphorous (P) availability imposes selection on community assemblage and influences their community turnover among fertilizations. When P nutrient lacks, the effect of environmental filtering becomes stronger, hence bacterial functional traits become more coherent; this process results into increased intraspecific interactions characterized by co-occurrence network analysis. In contrast, when P nutrient becomes abundant, the environmental selection is mitigated; function traits are evened. This process reduces intraspecific interactions and increases carbon sequestration efficiency, which is finally of great favor to the increases in soil fertility. This study has made the first attempt, at the bacterial level, to understand how fertilization affects agroecosystems. When more phylogenetic information on how nutrient cycling-related microbes respond to fertilization becomes available, the systematic knowledge will eventually provide guidance to optimal fertilization strategies.

Introduction: Ammonia oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB) have been proven to be key microorganisms driving the ammonia oxidation process. However, under different fertilization practices, there is a lack of research on the impact of interaction between predators and AOA or AOB on nitrogen cycling at the multi-trophic level. Methods: In this study, a network-oriented microscopic culture experiment was established based on four different long-term fertilization practices soils. We used the nitrification inhibitors 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxide-3-oxyl (PTIO) and 3, 4-Dimethylpyrazole phosphate (DMPP) inhibited AOA and AOB, respectively, to explore the impact of interaction between protists and AOA or AOB on nitrogen transformation. Results: The results showed that long-term nitrogen application promoted the potential nitrification rate (PNR) and nitrous oxide (N2O) emission, and significantly increased the gene abundance of AOB, but had no obvious effect on AOA gene abundance. DMPP significantly reduced N2O emission and PNR, while PTIO had no obvious effect on them. Accordingly, in the multi-trophic microbial network, Cercozoa and Proteobacteria were identified as keystone taxa of protists and AOB, respectively, and were significantly positively correlated with N2O, PNR and nitrate nitrogen. However, Nitrososphaerota archaeon as the keystone species of AOA, had an obvious negative linkage to these indicators. The structural equation model (SEM) showed that AOA and AOB may be competitors to each other. Protists may promote AOB diversity through direct trophic interaction with AOA. Conclusion: The interaction pattern between protists and ammonia-oxidizing microorganisms significantly affects potential nitrification rate and N2O emission, which has important implications for soil nitrogen cycle. [ABSTRACT FROM AUTHOR]

Fertilization has a large impact on the soil microbial communities, which play pivotal roles in soil biogeochemical cycling and ecological processes. While the effects of changes in nutrient availability due to fertilization on the soil microbial communities have received considerable attention, specific microbial taxa strongly influenced by long-term organic and inorganic fertilization, their potential effects and associations with soil nutrients remain unclear. Here, we use deep 16S amplicon sequencing to investigate bacterial community characteristics in a fluvo-aquic soil treated for 24 years with inorganic fertilizers and organics (manure and straw)-inorganic fertilizers, and uncover potential links between soil nutrient parameters and specific bacterial taxa. Our results showed that combined organic-inorganic fertilization increased soil organic carbon (SOC) and total nitrogen (TN) contents and altered bacterial community composition, while inorganic fertilization had little impact on soil nutrients and bacterial community composition. SOC and TN emerged as themajor determinants of community composition. The abundances of specific taxa, especially Arenimonas, Gemmatimonas, and an unclassified member of Xanthomonadaceae, were substantially increased by organic-inorganic amendments rather than inorganic amendments only. A co-occurrence based network analysis demonstrated that SOC and TN had strong positive associations with some taxa (Gemmatimonas and the members of Acidobacteria subgroup 6, Myxococcales, Betaproteobacteria, and Bacteroidetes), and Gemmatimonas, Flavobacterium, and an unclassified member of Verrucomicrobia were identified as the keystone taxa. These specific taxa identified above are implicated in the decomposition of complex organic matters and soil carbon, nitrogen, and phosphorus transformations. The present work strengthens our current understanding of the soil microbial community structure and functions under long-term fertilization management and provides certain theoretical support for selection of rational fertilization strategies. [ABSTRACT FROM AUTHOR]