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Increasing density is an effective way to enhance wheat (Triticum aestivum L.) yield under limited cultivated areas. However, the physiological mechanisms underlying the reduction in grain weight when density increased are still unclear. Three field experiments were conducted during the 2014–2019 growing seasons to explore the physiological mechanisms by which polyamines affect grain weight formation. The results showed that when wheat planting density exceeded 450 × 104 seedlings ha−1 and 525 × 104 seedlings ha−1, wheat yield tended to decrease. Compared to moderate density (DM, 450 × 104 seedlings ha−1), the filling rate of inferior grains was reduced before 25 days after anthesis (DAA) and the active filling period was shortened by 6.4%–7.4% under high density (DH, 600 × 104 seedlings ha−1), resulting in a loss of 1000‐grain weight by 5.4%–8.1%. DH significantly reduced sucrose and starch content in inferior grains at the filling stage. Meanwhile, DH inhibited the activity of key enzymes involved in polyamine synthesis [SAMDC (EC 4.1.1.50) and SpdSy (EC 2.5.1.16)] and induced the activity of ethylene (ETH) precursor synthase, resulting in a significant decrease in endogenous spermidine (Spd) content in inferior grains, but a significant increase in ETH release rate. Post‐flowering application of exogenous Spd increased the accumulation of sucrose and starch in the inferior grains and positively regulated the filling and grain weight of the inferior grains, whereas exogenous ETH had a negative effect. Overall, Spd may affect wheat grain weight at high planting density by promoting the synthesis of sucrose and starch in inferior grains. [ABSTRACT FROM AUTHOR]

Lung cancer is the leading global cause of cancer‐related death, however, resistance to chemotherapy drugs remains a huge barrier to effective treatment. The elevated recruitment of myeloid derived suppressor cells (MDSCs) to tumour after chemotherapy has been linked to resistance of chemotherapy drugs. Nevertheless, the specific mechanism remains unclear. oxPAPC is a bioactive principal component of minimally modified low‐density lipoproteins and regulates inflammatory response. In this work, we found that cisplatin, oxaliplatin and ADM all increased oxPAPC release in tumour. Treating macrophages with oxPAPC in vitro stimulated the secretion of MCP‐1 and LTB4, which strongly induced monocytes and neutrophils chemotaxis, respectively. Injection of oxPAPC in vivo significantly upregulated the percentage of MDSCs in tumour microenvironment (TME) of wild‐type LL2 tumour‐bearing mice, but not CCL2−/− mice and LTB4R−/− mice. Critically, oxPAPC acted as a pro‐tumor factor in LL2 tumour model. Indeed, cisplatin increased oxPAPC level in tumour tissues of WT mice, CCL2−/− and LTB4R−/− mice, but caused increased infiltration of Ly6Chigh monocytes and neutrophils only in WT LL2‐bearing mice. Collectively, our work demonstrates cisplatin treatment induces an overproduction of oxPAPC and thus recruits MDSCs infiltration to promote the tumour growth through the MCP‐1/CCL2 and LTB4/LTB4R pathways, which may restrict the effect of multiple chemotherapy. This provides evidence for a potential strategy to enhance the efficacy of multiple chemotherapeutic drugs in the treatment of lung cancer by targeting oxPAPC. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to infer the allocation of belowground net primary productivity (BNPP) to sequential soil depths down to 2 m across the globe at a 1 km resolution and assess underlying environmental drivers. Location: Global. Time Period: Contemporary (1932–2017). Major Taxa Studied: Terrestrial plants. Methods: Global datasets including field net primary production (NPP, i.e., the difference between plant assimilated and respired carbon) from 725 soil profiles, root biomass and its depth distribution from 559 soil profiles were compiled and used to infer the depth distribution of BNPP across the globe and digitally map depth‐resolved BNPP globally at 1 km resolution. Drivers of the depth distribution of BNPP were evaluated using machine learning‐based models. Results: Global average BNPP allocated to the 0–20 cm soil layer is estimated to be 1.1 Mg C ha−1 yr−1, accounting for ~60% of total BNPP. Across the globe, the depth distribution of BNPP varies largely, and more BNPP is allocated to deeper layers in hotter and drier regions. Edaphic, climatic and topographic properties (in order of importance) explain >80% of such variability; and the direction and magnitude of the influence of individual properties are soil depth‐ and biome‐dependent. Main Conclusions: The findings suggest that mean annual temperature and precipitation are the two most important factors regulating BNPP across the globe. Soil properties such as soil actual evaporation and total nitrogen also play a vital role in regulating the depth distribution of BNPP. The maps of BNPP provide global benchmarks of depth‐resolved BNPP for the prediction of whole‐profile soil carbon dynamics across biomes. [ABSTRACT FROM AUTHOR]

Soil organic carbon (SOC) transformation is susceptible to tillage practices. Conservation tillage is known to optimize soil structure, improve microbial community diversity and increase SOC storage. However, how soil aggregate distribution and microbial community structure and function within aggregates affect SOC transformation under long‐term conservation tillage remains unclear. In this study, SOC mineralization dynamics were studied in situ and under laboratory conditions to examine the mechanisms by which C functional genes within soil aggregates of different sizes (i.e., mega‐, macro‐, and micro‐aggregates) influence SOC mineralization under long‐term tillage (i.e., zero, chisel, and plow tillage) in a dryland. The results indicated that in the winter wheat and summer maize rotation cropping system, SOC‐derived CO2‐C emissions were 143.99 and 133.29 g CO2‐C m−2 h−1 lower under chisel and zero tillage than that under plow tillage, respectively. Moreover, after 180 days of laboratory incubation, SOC mineralization in micro‐ and macro‐aggregates was 1.98 and 1.63 mg CO2‐C g−1 d−1 higher than that in mega‐aggregates, respectively. The aggregate‐associated differential modules of bacterial co‐occurring networks may be directly governed by bacterial community diversity and composition, which might play critical roles in driving SOC mineralization in response to different tillage intensities. Moreover, aggregate‐associated functional genes involved in labile and recalcitrant C compositions, which were determined by shotgun metagenomic sequencing, were associated with SOC mineralization and were significantly affected by the legacy effect of tillage intensity and aggregate size. Particularly, partial least squares path modeling revealed that genes involved in simple sugar metabolism exerted significantly positive effects on SOC mineralization, except for the effects of tillage intensity and aggregate size. Overall, this study showed that decreased abundances of labile C decomposition‐related functional genes within aggregates and community composition changes, as elucidated by the differences in bacterial network modules, under conservation tillage inhibit SOC mineralization. These findings may help in the development of adaptive soil tillage strategies for reducing carbon emissions in agroecosystems. [ABSTRACT FROM AUTHOR]

The microbial priming effect—the decomposition of soil organic carbon (SOC) induced by plant inputs—has long been considered an important driver of SOC dynamics, yet we have limited understanding about the direction, intensity, and drivers of priming across ecosystem types and biomes. This gap hinders our ability to predict how shifts in litter inputs under global change can affect climate feedbacks. Here, we synthesized 18,919 observations of CO2 effluxes in 802 soils across the globe to test the relative effects (i.e., log response ratio [RR]) of litter additions on native SOC decomposition and identified the dominant environmental drivers in natural ecosystems and agricultural lands. Globally, litter additions enhanced native SOC decomposition (RR = 0.35, 95% CI: 0.32–0.38), with greater priming effects occurring with decreasing latitude and more in agricultural soils (RR = 0.43) than in uncultivated soils (RR = 0.28). In natural ecosystems, soil pH and microbial community composition (e.g., bacteria: fungi ratio) were the best predictors of priming, with greater effects occurring in acidic, bacteria‐dominated sandy soils. In contrast, the substrate properties of plant litter and soils were the most important drivers of priming in agricultural systems since soils with high C:N ratios and those receiving large inputs of low‐quality litter had the highest priming effects. Collectively, our results suggest that, though different factors may control priming effects, the ubiquitous nature of priming means that alterations of litter quality and quantity owing to global changes will likely have consequences for global C cycling and climate forcing. [ABSTRACT FROM AUTHOR]

Background: The potential role of circFNDC3B in regulating oral tongue squamous cell carcinoma development (OTSCC) remains unknown. Methods: The level of circFNDC3B in OTSCC tissues or cell lines was measured and its function in vitro and in vivo was analyzed. Interactions among circFNDC3B, miR‐1322, and MED1 were verified by luciferase reporter and RNA pull‐down assays. Results: The level of circFNDC3B in tissues or cell lines of OTSCC was higher than that in control groups. siRNA‐mediated circFNDC3B inhibition resulted in weakened proliferation, migration, and invasion, which was reversed by miR‐1322. Overexpression of MED1 in OTSCC cells partially reversed the tumor suppression functions of si‐circFNDC3B or miR‐1322 mimics in vitro. circFNDC3B overexpression dramatically promoted tumor growth in vivo. circFNDC3B directly bound with miR‐1322 and consequently promoted the MED1 expression in OTSCC cells. Conclusions: The circFNDC3B/miR‐1322/MED1 axis participates in OTSCC progression, which may provide novel therapeutic targets for OTSCC. [ABSTRACT FROM AUTHOR]

Aim: Fresh carbon (C) inputs to the soil can have important consequences for the decomposition rates of soil organic matter (priming effect), thereby impacting the delicate global C balance at the soil–atmosphere interface. Yet, the environmental factors that control soil priming effect intensity remain poorly understood at a global scale. Location: Global. Time period: 1980–2020. Major taxa studied: Soil priming effect intensity. Methods: We conducted a global dataset of CO2 effluxes in 711 pairwise soils with 13C or 14C simple C sources inputs and without C inputs from incubation experiments in which isotope‐labelled C was used to quantify fresh C‐induced rather than exudate‐induced priming. Results: Soil priming effect intensity is predominantly positive. Soil texture and C content were identified as the most important factors associated with priming effects, with sandy soils from tropical and mid‐latitudes supporting the highest soil priming effect intensity, and soils with greater C content and fine textures from high latitudes maintaining the lowest soil priming effects. The negative association between C content and soil priming effect intensity was also indirectly driven by changing mean annual temperature, net primary productivity, and fungi : bacteria ratio. Using this information, we generated a global map of soil priming effect intensity, and found that the priming was lower at high latitudes and higher at lower latitudes. Main conclusions: Global patterns of soil priming effect intensity can be predicted using environmental data, with soil texture and C content playing a predominant role in explaining in priming effects. These effects were also indirectly driven by climate, vegetation and soil microbial properties. We present the first global atlas of soil priming effect intensity and advance our knowledge on the potential mechanisms underlying soil priming effect intensity, which are integral to improving the climate change and soil C dynamics components of Earth System models. [ABSTRACT FROM AUTHOR]

Single infrared (IR) image super‐resolution methods can help to reduce the cost and difficulty in manufacturing IR sensors for the imaging system. However, the deep learning‐based image SR methods need to build a complex network and thus consume a lot of computational power, which limits the application of SR technology on devices with low computing resources in practice. To solve this problem, the authors present a lightweight multi‐path feature fusion network (MFFN) for the single infrared (IR) image SR. A multi‐path feature fusion block (MFFB) is developed to extract and fuse multiple and discriminative features in a recursive feedback way. Specifically, the multiple features are refined via the linear feature extraction branch, shared‐source residual feature extraction branch, and channel attention branch in MFFB. Finally, the authors reconstruct the high‐resolution IR images from the low‐resolution counterpart based on the refined multiple features. The experimental results demonstrate that MFFN achieves high‐quality single infrared image SR and shows superiority over previous methods for several scale factors (e.g. ×2, ×3, and ×4). MFFN has potential applications in the mobile infrared imaging system. [ABSTRACT FROM AUTHOR]

BACKGROUND: Ridge–furrow mulching farming systems (RFMs) aim to increase field productivity and improve water use efficiency. To explore environment‐friendly and efficient farming systems is a central aspect of rainfed wheat field management in Kenya where rainfall utilization is at a low level. We introduced RFMs (including plastic film and grass straw mulching) to semiarid Kenya to evaluate the effects on field productivity, rainwater utilization, soil quality and economic profitability using old and modern wheat cultivars from 2012 to 2013. RESULTS: Across the cultivars, the RFMs increased grain yield, aboveground biomass and water use efficiency by 74–163%, 36–104% and 89–273%, respectively, compared with conventional flat planting (control). RFMs significantly shortened the vegetative period while prolonging the reproductive period. The net economic output under RFMs was 74–165% higher than that of the control. Grass straw mulching achieved the highest economic output to input ratio, almost 45% higher than plastic film mulching, despite the former harvested only 82% of the maximum field productivity of the latter. Compared with the control, grass straw mulching promoted the contents of soil organic carbon, total nitrogen and C:N ratio by 14%, 8% and 5%, respectively, while obviously decreased values of these parameters were observed under plastic mulching. CONCLUSIONS: Through reducing soil water loss, and improving rainwater use efficiency and soil quality, ridge–furrow grass straw mulching would be a sustainable option for boosting field productivity and thus ensuring local food security in rainfed agricultural areas of Kenya. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Farming practices that integrate plastic film mulching and nitrogen (N) fertilization have been extensively used to enhance crop productivity. However, the interactive effects of mulching and N application on soil microbial properties and crop yields have received little attention. A 2‐year field experiment was carried out in the Loess Plateau to investigate the independent and combined effects of plastic mulch and N application rate on the soil microbial population, enzymatic activity and grain yield. From 2016 to 2017, two mulching patterns (i.e., plastic mulching and no mulching) were exposed to five different N application rates (0 (N0), 80 (N80), 160 (N160), 200 (N200) and 240 (N240) kg N ha−1). N application significantly affected the soil microbial community composition, as suggested by significant increases in soil total bacteria, cellulose‐decomposing bacteria and the bacterial‐to‐fungal ratio with N rates. In contrast, the mulching pattern significantly affected soil extracellular enzyme production. Furthermore, there were significant effects of mulching, N application and their interaction on grain yield. The highest grain yield (11,728 kg N ha−1 in 2016 and 12,350 kg N ha−1 in 2017) in both growing seasons was consistently obtained under plastic mulching with a N level of 200 kg N ha−1. Our study showed that plastic mulching significantly affected extracellular enzyme production, and N fertilizer application significantly affected the composition of the soil microbial community. Highlights: Independent and coupled effects of mulching and N application on soil biological properties and grain performance were explored.N application significantly influenced soil microbial community composition.Mulching pattern rather than N application independently and significantly affected soil extracellular enzyme productionThe combined application of plastic mulching with 200 kg N ha−1 should be seem as an optimum crop production pattern in this area. [ABSTRACT FROM AUTHOR]

Influenced by natural fractures, fracture networks may be created when hydraulic fractures propagate in naturally fractured reservoirs. Simulating fracture network propagation is crucial to fracture design. In this paper, a two‐dimensional mathematical model for the direct simulation of fracture network propagation that considers fluid filtration and reservoir fluid flow is developed, and a simulation method is proposed based on the coupled flow idea of natural fractures and matrices in dual‐porosity media. The model uses dynamic coordinates to represent the extended hydraulic fracture network and static coordinates to describe natural fractures that have not been activated. The activation of natural fractures by a hydraulic fracture is determined according to the hydraulic fracture propagation scenario after an intersection with natural fractures. The geometric shape and size of the network fracture are obtained by changing the size of the simulated area and solving the mass balance, fracture width, and reservoir fluid flow equations numerically in a coupled manner. After validating the new model, a parameter sensitivity analysis is conducted to study the effects of injected fluid volume, fracture height, fracture spacing, elastic modulus, horizontal principal stress difference, pumping rate, and fracturing fluid viscosity on the fracture network shape, fracture network size, average fracture width, and fracture‐reservoir contact area. The numerical results indicate that the model can be directly used to simulate the propagation of fracture networks. The volume of injected fluid is the most critical factor affecting the fracture network size. Increasing the fluid viscosity and injection rate can increase the width of the fracture network and the average width of a secondary fracture. However, the total contact area of the reservoir and fracture will decrease, and the reservoir‐fracture contact area and fracture network size will increase with a decrease in the horizontal stress difference and increase in elastic modulus. Decreasing a fracture's height can significantly increase the size of the fracture network and reservoir‐fracture contact area. [ABSTRACT FROM AUTHOR]

Farmland surface soil mulching with plastic film is extensively used to enhance agricultural productivity in the Loess Plateau (LP). However, the effect of mulching on the key processes that dominate soil nitrogen dynamics is rarely assessed quantitatively. We quantified the responses of agroecosystem nitrogen cycling to plastic mulching using a comprehensive database drawn from mulching experiments in the LP. Our results indicated that through increasing the soil mineral and dissolved organic nitrogen concentrations, plastic mulching significantly enhanced the soil nitrogen availability by 36.6% at the regional scale, compared with traditional nonmulching. Mulching pattern, nitrogen application, and soil type were found to be the most significant drivers in determining nitrogen availability. Furthermore, nitrogen gaseous releases and hydrological leaching were significantly reduced by 7.0% and 9.4%, respectively, under plastic mulching, which led to an insignificant change in the soil total nitrogen pool. Nitrogen input level and soil organic carbon appeared to be the most important factors influencing soil nitrogen losses. Critically, along with increased root residue inputs to soil and improved water thermal conditions under mulching, soil microbial activity was increased significantly. This was indicated by enhanced microbial biomass nitrogen and soil nitrogen‐related extracellular enzyme activity and was driven by nitrogen input, mulching duration, and soil carbon status. We generalize that in the rain‐fed agroecosystems of the LP, plastic mulch will have little impact on nitrogen pool size, largely due to reduced gaseous and hydrological nitrogen losses and increased crop‐sourced nitrogen inputs, but will strongly stimulate microbial growth, metabolism, and activities, which consequently will speed up biogeochemical cycles of soil nutrients. [ABSTRACT FROM AUTHOR]

Poly‐γ‐glutamic acid (γ‐PGA) is an important multifunctional biopolymer with various applications, for which adenosine triphosphate (ATP) supply plays a vital role in biosynthesis. In this study, the enhancement of γ‐PGA production was attempted through various approaches of improving ATP supply in the engineered strains of Bacillus licheniformis. The first approach is to engineer respiration chain branches of B. licheniformis, elimination of cytochrome bd oxidase branch reduced the maintenance coefficient, leading to a 19.27% increase of γ‐PGA yield. The second approach is to introduce Vitreoscilla hemoglobin (VHB) into recombinant B. licheniformis, led to a 13.32% increase of γ‐PGA yield. In the third approach, the genes purB and adK in ATP‐biosynthetic pathway were respectively overexpressed, with the AdK overexpressed strain increased γ‐PGA yield by 14.69%. Our study also confirmed that the respiratory nitrate reductase, NarGHIJ, is responsible for the conversion of nitrate to nitrite, and assimilatory nitrate reductase NasBC is for conversion of nitrite to ammonia. Both NarGHIJ and NasBC were positively regulated by the two‐component system ResD–ResE, and overexpression of NarG, NasC, and ResD also improved the ATP supply and the consequent γ‐PGA yield. Based on the above individual methods, a method of combining the deletion of cydBC gene and overexpression of genes vgB, adK, and resD were used to enhance ATP content of the cells to 3.53 μmol/g of DCW, the mutant WX‐BCVAR with this enhancement produced 43.81 g/L of γ‐PGA, a 38.64% improvement compared to wild‐type strain WX‐02. Collectively, our results demonstrate that improving ATP content in B. licheniformis is an efficient strategy to improve γ‐PGA production. The respiratory chain is optimized to reduce metabolism coefficient, and the VHB and AdK are strengthened to improve ATP supply for enhanced γ‐PGA production. The roles of NarGHIJ, NasBC and ResD∼E are identified in the BFCNA medium during γ‐PGA production, and Strengthening of NarG, NasC and ResD improve the nitrate metabolism, ATP supply and γ‐PGA yield. The γ‐PGA yield produced by WX‐BCVAR is increased by 38.64% via improvement of ATP supply [ABSTRACT FROM AUTHOR]