Search

• SAAE inhibited the growth and adhesion of H. pylori. • SAAE alleviated the H. pylori OMVs induced inflammation responses. • SAAE counteracted the H. pylori OMVs caused anomalous regulation of AIFM2 and IGFBP3. • SAAE combated the H. pylori OMVs triggered cell autophagy. The aqueous extract of the dried buds of Syzygium aromaticum (SAAE) have the potential to alleviate Helicobacter pylori infection, but the specific molecular mechanism has not been fully elucidated. This study aimed to investigate the underlying mechanisms of SAAE on H. pylori pathogenicity. The inhibitory kinetics and anti- H. pylori adhesive capacity assays were conducted to examine the effects of SAAE on the growth and adhesive capability of H. pylori. The H. pylori outer membrane vesicles (OMVs) were purified from the culture supernatant through high-speed centrifugation, filtration, and two rounds of ultracentrifugation. Their characteristics and protein composition were then identified using transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and qualitative proteomics study. Subsequently, the effect of SAAE on the pathogenicity of H. pylori OMVs was investigated using the Griess reagent assay, enzyme-linked immunosorbent assay (ELISA), quantitative proteomics study, TEM, and western blotting assay. SAAE exhibited inhibitory effects on H. pylori growth and adhesion. The isolated H. pylori OMVs showed particle size of 27–242 nm and Zeta potential of −9.67 ± 0.53 mV. A total of 599 proteins were identified in the OMVs. Proteomics study indicated that the differential expressed proteins induced by OMVs with or without SAAE commonly enriched in P53 and autophagy pathways. Besides, SAAE counteracted the increased production of pro-inflammatory cytokines and attenuated the induction of cell autophagy caused by H. pylori OMVs. Furthermore, SAAE normalized the abnormal regulation of downstream targets (AIFM2 and IGFBP3) in the P53 signaling pathway caused by H. pylori OMVs. SAAE can inhibit the growth and adhesion of H. pylori , reduce the inflammation and autophagy induced by H. pylori OMVs, and combated the abnormal regulation of P53 signaling pathway caused by H. pylori OMVs. These findings may help elucidate the mechanisms through which SAAE reduces the pathogenicity of H. pylori. [Display omitted] [ABSTRACT FROM AUTHOR]

Highlights • Aggressive pigs were separated from the herd and extracted continuously. • Head and 4 kink points of pigs were located and used as feature points. • Kinetic energy model was built by analysing motion of these 5 feature points. • Kinetic energy difference between adjacent frames was used to recognise aggression. • The proposed algorithm has higher accuracy, sensitivity, specificity and precision. Abstract The aim of this study is to build a kinetic energy model to recognise aggressive behaviours in pigs. Pig mixing experiments were performed 10 times. In each experiment, 7 pigs from 3 pens were mixed and then videos of the first 3 h after mixing and the 3 h after 24 h were selected as experimental data. A 30 h data of 5 groups of pigs were used as training set and a 30 h data of another 5 groups of pigs as test set. Firstly, according to connected area and adhesion index, aggressive pigs were separated from the herd and then key frame sequences with aggression were extracted. Secondly, head and 4 kink points of pigs were selected as feature points. By analysing motion of these points, kinetic energy of 2 aggressive pigs was calculated and kinetic energy difference between adjacent frames was selected as features. Finally, these features were trained by using hierarchical clustering to obtain the thresholds of high and medium aggression. These thresholds were used to design the rule of aggression recognition. By using the proposed algorithm, high aggression could be recognised with an accuracy of 95.8%, a sensitivity of 92.8%, specificity of 96.7% and precision of 90.2%, and medium aggression could be recognised with an accuracy of 92.3%, a sensitivity of 92.6%, specificity of 91.9% and precision of 93.0%. The results indicate that this algorithm can be used to recognise aggressive behaviours of pigs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Syzygium aromaticum aqueous extract (AE) enhanced innate immunity by inducing macrophages M1 polarization. • AE inhibited the Nrf2/HO-1 signal while activated the TLR4/Myd88 mediated NF-κB and MAPK pathways in macrophages. • AE alleviated Helicobacter pylori infection-related inflammation. Previous studies suggested that Syzygium aromaticum dried buds (S. aromaticum), which is an edible and medicinal herb, possess potential effect on innate immunity and Helicobacter pylori (H. pylori) infection-related inflammation, but the specific action and especially the molecular mechanism have not been well elucidated. The objective of this work was to further explore the effects of Syzygium aromaticum aqueous extract (AE) on innate immunity and H. pylori related-inflammation, especially the potential molecular mechanisms involved. In order to accomplish this, analyses of the phagocytic rate, NO content, ROS level, as well as ELISA, RT-qPCR, and Western blotting et al. assays were carried out. Results indicated that AE increased phagocytic rate, ROS, and cytokine expression levels, meanwhile activated TLR4/MyD88 mediated NF-κB and MAPK pathways and decreased Nrf2/HO-1 signaling. AE also prevented the release of pro-inflammatory substances made by H. pylori -infected RAW 264.7 and GES-1 cells. All things considered, it was shown that AE's ability to boost innate immunity involves inducing macrophage M1 polarization by increasing TLR4/MyD88-mediated NF-κB and MAPK pathways and blocking Nrf2/HO-1 signaling. Additionally, by lowering the production of pro-inflammatory molecules, AE can lessen the inflammation brought on by H. pylori. Considering that S. aromaticum is an edible herbal medicine with immune-enhancing activity and good safety, it deserves further study and utilization for treating diseases including H. pylori infection-related disorders. [ABSTRACT FROM AUTHOR]

The impacts of increasing nitrogen (N) deposition on forest ecosystems, including on carbon (C) sequestration, largely depend on the extent to which forests are N-limited and so whether and where deposited N is retained within the ecosystem. The 15 N tracer method can provide excellent insight into the ecosystem fates of N, but while it has been extensively used in temperate forests it has yet to be sufficiently employed in tropical forests, which are often thought not to be N-limited. Here, we used stable isotope 15 NH 4 + and 15 NO 3 − tracers applied as solutions to the forest floor to examine the fates of different forms of N in a tropical montane primary forest with low background atmospheric N deposition (6 kg N ha −1  yr −1 ) in China. We found that a substantial amount of 15 N was assimilated by plants over time and significantly more 15 N was recovered following 15 NO 3 − addition than following 15 NH 4 + addition: 7% and 16% of 15 N were recovered three months after the respective 15 NH 4 + and 15 NO 3 − tracer additions and 11% and 29% respectively after one year. In contrast to plants, the organic layer was only an important short-term sink for deposited N: while 21% and 12% of the 15 N from 15 NH 4 + and 15 NO 3 − additions were accumulated in the organic layer after three months, more than half of the retained 15 N was lost after one year. Mineral soil was the largest sink for deposited N, and the 15 N retained in soil was relatively stable over time for both N forms, with 39% and 32% of the initial 15 N input recovered after one year for 15 NH 4 + and 15 NO 3 − tracer additions, respectively. Overall, the total ecosystem 15 N recovery one year after the 15 NH 4 + and 15 NO 3 − tracer additions was large (60% and 66% respectively), and not significantly different from total recovery after three months, suggesting that a large proportion of deposited N could be retained in the longer term. Based on the measured fate of 15 N one year after labeling and the C:N ratios of different plant components, this tropical forest’s carbon sequestration efficiency is calculated to be 17 kg C per kg N added, comparable to the values reported for temperate and boreal forests in Europe and North America and indicating substantial N limitation of this tropical forest. Our results suggest that anthropogenic N input in moderate levels may contribute to enhance C sequestration in some tropical forests, without significant long-term loss of N to the environment. [ABSTRACT FROM AUTHOR]

The biogenesis of chitin, a major structural polysaccharide found in the cuticle and peritrophic matrix, is crucial for insect growth and development. Chitin synthase, a membrane-integral β-glycosyltransferase, has been identified as the core of the chitin biogenesis machinery. However, a yet unknown number of auxiliary proteins appear to assist in chitin biosynthesis, whose precise function remains elusive. Here, we identified a sarco/endoplasmic reticulum Ca2+-ATPase (SERCA), in the fruit fly Drosophila melanogaster , as a chitin biogenesis-associated protein. The physical interaction between Dm SERCA and epidermal chitin synthase (Krotzkopf verkehrt, Kkv) was demonstrated and analyzed using split-ubiquitin membrane yeast two-hybrid, bimolecular fluorescent complementation, pull-down, and immunoprecipitation assays. The interaction involves N-terminal regions (aa 48–81 and aa 247–33) and C-terminal regions (aa 743–783 and aa 824–859) of Dm SERCA and two N-terminal regions (aa 121–179 and aa 369–539) of Kkv, all of which are predicted be transmembrane helices. While tissue-specific knock-down of DmSERCA in the epidermis caused larval and pupal lethality, the knock-down of DmSERCA in wings resulted in smaller and crinkled wings, a significant decrease in chitin deposition, and the loss of chitin lamellar structure. Although Dm SERCA is well-known for its role in muscular contraction, this study reveals a novel role in chitin synthesis, contributing to our knowledge on the machinery of chitin biogenesis. [Display omitted] • Epidermal chitin synthase-interacting candidates are identified by TAP-MS in fly. • Sarco/endoplasmic reticulum Ca2+-ATPase interacts with epidermal chitin synthase. • The Dm SERCA-Kkv interaction involves several predicted transmembrane helices. • Dm SERCA functions in cuticle chitin biosynthesis. [ABSTRACT FROM AUTHOR]

Highlights: [•] We evaluated nitrogen (N) dynamics in an urban constructed wetland under base-flow and storm-flow. [•] N concentrations were reduced under base-flow in all sampling years and all seasons except winter. [•] Over the 4-year sampling period, 38% of the N entering the wetland during base-flow was removed. [•] N was removed in 2 of the 7 storm events sampled and overall N-export was 34% greater than the input. [•] N retention and export in urban constructed wetlands are highly dependent on hydrologic discharge. [ABSTRACT FROM AUTHOR]

Chitin is an aminopolysaccharide present in insects as a major structural component of the cuticle. However, current knowledge on the chitin biosynthetic machinery, especially its constituents and mechanism, is limited. Using three independent binding assays, including co-immunoprecipitation, split-ubiquitin membrane yeast two-hybrid assay, and pull-down assay, we demonstrate that choline transporter-like protein 2 (Ctl2) interacts with krotzkopf verkehrt (kkv) in Drosophila melanogaster. The global knockdown of Ctl2 by RNA interference (RNAi) induced lethality at the larval stage. Tissue-specific RNAi to silence Ctl2 in the tracheal system and in the epidermis of the flies resulted in lethality at the first larval instar. The knockdown of Ctl2 in wings led to shrunken wings containing accumulated fluid. Calcofluor White staining demonstrated reduced chitin content in the first longitudinal vein of Ctl2 knockdown wings. The pro-cuticle, which was thinner compared to wildtype, exhibited a reduced number of chitin laminar layers. Phylogenetic analyses revealed orthologues of Ctl2 in different insect orders with highly conserved domains. Our findings provide new insights into cuticle formation, wherein Ctl2 plays an important role as a chitin-synthase interacting protein. [Display omitted] • Choline transporter-like protein 2 interacts with chitin synthase 1. • Ctl2 is necessary for chitin synthesis in chitin-containing organs. • Multiple motifs in Ctl2 are involved in the interaction to N-terminal region of kkv. • Putative orthologues of Ctl2 are found in different insect orders. • The gene expression pattern of Ctl2 during development is similar to that of kkv. [ABSTRACT FROM AUTHOR]

Abstract: Constructed wetlands are increasingly being used to treat wastewater, yet most remediation studies only focus on single pollutants (e.g. nitrogen [N] or phosphorus [P]) or pollutant classes (e.g. nutrients). For wetland remediation to be useful in urban systems, where storm generated wastewater often contains many different pollutant types (e.g. nutrients and metals), wetlands must be able to both tolerate and remediate these pollutant cocktails. Since plants are often integral to this treatment ability, the objective of our study was to evaluate the growth of three common wetland plants (Glyceria grandis, Typha latifolia and Sagittaria latifolia) treated with single and multi-pollutant wastewater types. We planted six replicate blocks within the research greenhouse at Binghamton University located in Binghamton, NY, USA. Each block contained 12 five-gallon pots filled with homogenized wetland sediment collected from a natural wetland on campus. Four pots were planted with G. grandis, four with T. latifolia and four with S. latifolia. Plants from each of the three species were assigned with one of four treatment solutions (dionized water [control], nitrate [NO3 −], metal mixture [Zn, Cu, Pb, Cd], or nitrate and metal mixture), and watered weekly for a total of seven weeks. Effluent was collected weekly and analyzed to determine weekly NO3–N efflux. At peak standing biomass, all roots and shoots were harvested to determine total aboveground and belowground biomass and N and P accumulation. Sediment was also collected to determine net N mineralization rates. We found that the NO3 − treatment, metal treatment and the combined NO3 − and metal treatment had no negative effect on plant growth and nutrient (N and P) content. However, G. grandis produced a greater amount of aboveground biomass (33.09±0.72g) and had a greater amount of N (450.9±25.3mg) in the aboveground biomass than T. latifolia (22.25±1.54g; 300.0±21.8mg) and S. latifolia (24.30±1.53g; 297.1±21.3mg). While S. latifolia sequestered a greater amount of P (181.6±11.1mg) than G. grandis (127.6±8.6mg) and T. latifolia (97.1±8.9mg). In addition, efflux NO3–N was substantially reduced by both plants and sediment, but plant presence caused a significantly greater NO3–N reduction than sediment alone. These findings indicate that wetland plants can grow well under single and multi-pollutant conditions, like those commonly found in urban systems, and that optimal ecosystem function would more likely occur in systems with multiple plant species assemblages. [Copyright &y& Elsevier]

Abstract: Dissolved inorganic nitrogen (DIN) (as ammonium nitrate) was applied monthly onto the forest floor of one old-growth forest (>400 years old, at levels of 50, 100 and 150kgNha−1 yr−1) and two young forests (both about 70 years old, at levels of 50 and 100kgNha−1 yr−1) over 3 years (2004–2006), to investigate how nitrogen (N) input influenced N leaching output, and if there were differences in N retention between the old-growth and the young forests in the subtropical monsoon region of southern China. The ambient throughfall inputs were 23–27kgNha−1 yr−1 in the young forests and 29–35kgNha−1 yr−1 in the old-growth forest. In the control plots without experimental N addition, a net N retention was observed in the young forests (on average 6–11kgNha−1 yr−1), but a net N loss occurred in the old-growth forest (−13kgNha−1 yr−1). Experimental N addition immediately increased DIN leaching in all three forests, with 25–66% of added N leached over the 3-year experiment. At the lowest level of N addition (50kgNha−1 yr−1), the percentage N loss was higher in the old-growth forest (66% of added N) than in the two young forests (38% and 26%). However, at higher levels of N addition (100 and 150kgNha−1 yr−1), the old-growth forest exhibited similar N losses (25–43%) to those in the young forests (28–43%). These results indicate that N retention is largely determined by the forest successional stages and the levels of N addition. Compared to most temperate forests studied in Europe and North America, N leaching loss in these seasonal monsoon subtropical forests occurred mainly in the rainy growing season, with measured N loss in leaching substantially higher under both ambient deposition and experimental N additions. [Copyright &y& Elsevier]

Nitric oxide (NO) plays a critical role in atmospheric chemistry and also is a precursor of nitrate, which affects particle matter formation and nitrogen deposition. Agricultural soil has been recognized as a main source of atmospheric NO. However, quantifying the NO fluxes emitted from croplands remains a challenge and in situ long-term measurements of NO are still limited. In this study, we used an automated sampling system to measure NO fluxes with a high temporal resolution over two years (April 2017 to March 2019) from a rainfed maize field in the Northeast China. The cumulative annual NO emissions were 8.9 and 2.3 kg N ha−1 in year 1 (April 2017 to March 2018) and year 2 (April 2018 to March 2019), respectively. These interannual differences were largely related to different weather conditions encountered. In year 1, a month-long drought before and after the seeding and fertilizing reduced plant N uptake and dramatically increased soil N concentration. The following moderate rainfalls promoted large amount of NO emissions, which remained high until late September. The NO fluxes in both years showed clearer seasonal patterns, being highest after fertilizer application in summer, and lowest in winter. The seasonal patterns of NO fluxes were mainly controlled by soil available N concentrations and soil temperatures. The contribution of NO fluxes during the spring freeze-thaw in both years was no more than 0.2% of the annual NO budget, indicating that the freeze-thaw effect on agricultural NO emissions was minimal. In addition, with high-resolution monitoring, we found that soil not only act as a NO source but also a sink. Long-term and high-resolution measurements help us better understand the diurnal, seasonal, and annual dynamics of NO emissions, build more accurate models and better estimate global NO budget and develop more effective policy responses to global climate change. [Display omitted] • Soil NO flux was measured in a maize field with an automatic method over 2 years. • Annual NO emissions were 8.9 and 2.3 kg N ha−1 in year 1 and 2, respectively. • Intensified drought caused NO as an important pathway in rainfed agriculture N loss. • The NO emissions during freeze-thaw period contributed <0.2% to annual NO loss. [ABSTRACT FROM AUTHOR]

Chitin, the major structural polysaccharide in arthropods such as insects and mites, is a linear polymer of N -acetylglucosamine units. The growth and development of insects are intimately coupled with chitin biosynthesis. The membrane-bound β-glycosyltransferase chitin synthase is known to catalyze the key polymerization step of N -acetylglucosamine. However, the additional proteins that might assist chitin synthase during chitin biosynthesis are not well understood. Recently, fatty acid binding protein (Fabp) has been suggested as a candidate that interacts with the chitin synthase Krotzkopf verkehrt (Kkv) in Drosophila melanogaster. Here, using split-ubiquitin membrane yeast two-hybrid and pull-down assays, we have demonstrated that the Fabp-B splice variant physically interacts with Kkv in vitro. The global knockdown of Fabp in D. melanogaster using RNA interference (RNAi) induced lethality at the larval stage. Moreover, in tissue-specific RNAi experiments, silenced Fabp expression in the epidermis and tracheal system caused a lethal larval phenotype. Fabp knockdown in the wings resulted in an abnormal wing development and uneven cuticular surface. In addition to reducing the chitin content in the first longitudinal vein of wings, Fabp silencing also caused the loss of procuticle laminate structures. This study revealed that Fabp plays an important role in chitin synthesis and contributes to a comprehensive understanding of the complex insect chitin biosynthesis. [Display omitted] • Fatty acid binding protein associates with chitin biosynthesis in Drosophila melanogaster. • Whole-body knock down of fatty acid binding protein induced lethal larval phenotypes. • Wing-specific knockdown led to abnormal wing development with uneven surfaces. • Fatty acid binding protein suppression caused loss of pro-cuticle laminate structures. [ABSTRACT FROM AUTHOR]

Denitrification is a major process contributing to the removal of nitrogen (N) from ecosystems, but its rate is difficult to quantify. The natural abundance of isotopes can be used to identify the occurrence of denitrification and has recently been used to quantify denitrification rates at the ecosystem level. However, the technique requires an understanding of the isotopic enrichment factor associated with denitrification, which few studies have investigated in forest soils. Here, soils collected from two tropical and two temperate forests in China were incubated under anaerobic or aerobic laboratory conditions for two weeks to determine the N and oxygen (O) isotope enrichment factors during denitrification. We found that at room temperature (20 °C), NO 3 − was reduced at a rate of 0.17 to 0.35 μg N g −1 h −1 , accompanied by the isotope fractionation of N ( 15 ε ) and O ( 18 ε ) of 31‰ to 65‰ (48.3 ± 2.0‰ on average) and 11‰ to 39‰ (18.9 ± 1.7‰ on average), respectively. The N isotope effects were, unexpectedly, much higher than reported in the literature for heterotrophic denitrification (typically ranging from 5‰ to 30‰) and in other environmental settings (e.g., groundwater, marine sediments and agricultural soils). In addition, the ratios of Δδ 18 O:Δδ 15 N ranged from 0.28 to 0.60 (0.38 ± 0.02 on average), which were lower than the canonical ratios of 0.5 to 1 for denitrification reported in other terrestrial and freshwater systems. We suggest that the isotope effects of denitrification for soils may vary greatly among regions and soil types and that gaseous N losses may have been overestimated for terrestrial ecosystems in previous studies in which lower fractionation factors were applied. [ABSTRACT FROM AUTHOR]

Eight triflavonoids, selagintriflavonoids A-H, were isolated from whole herbs of Selaginella doederleinii . The structures of compounds selagintriflavonoids A-C consisted of three naringenin units, whereas those of selagintriflavonoids D-H consisted of apigenin and two naringenin moieties. The structures and absolute configurations of the compounds were determined based on NMR, HRESIMS, and experimental and calculated electronic circular dichroism (ECD) data. The ability of the compounds to inhibit β -secretase (BACE1) was also evaluated. All compounds exhibited BACE1 inhibition with IC 50 values ranging from 0.75 to 46.99 μ M. Selagintriflavonoid A exhibited the strongest inhibition (0.75 μ M) and is thus a promising compound for treating Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Five new carboxymethyl flavonoids named 5-carboxymethyl-3′, 4′, 7-trihydroxyflavone ( 1 ), (2 S )- 5-carboxymethyl-3′, 4′, 7-trihydroxyflavonone ( 2a ), (2 R )-5-carboxymethyl-3′, 4′, 7-trihydroxyflavonone ( 2b ), (2 S )-5-carboxymethyl-4′, 7-dihydroxyflavonone ( 3 ), 5- carbomethoxymethyl-4′, 7-dihydroxyflavone ( 4 ), and a new chromone named 5-carboxymethyl-7-hydroxychromone ( 5 ), together with two known compounds 5-carboxymethyl-4′-hydroxyflavone-7- O - β - d -glucopyranoside ( 6 ), 5-carboxymethyl-4′, 7-dihydroxyflavone ( 7 ) were isolated from Selaginella moellendorffii Hieron. Their structures including absolute configuration were elucidated by extensive spectroscopic methods and experimental electronic circular dichroism (ECD) spectra. What's worth mentioning is that a carboxymethyl substituent appeared at the C-5 position of all isolated compounds, only recently discovered in genus Selaginella . Compounds 2a and 2b were identified as a pair of chiral isomers; compound 5 was discovered as the first chromone comprising a carboxymethyl side chain. Furthermore, all compounds were evaluated for their antibacterial activities against various Gram-positives and Gram-negatives, and compared to the reference drugs amoxicillin and norfloxacin. As a result, compounds 3 and 4 exhibited as potent antimicrobial agents with a broad spectrum, and compound 5 appeared as the most promising one to combat Gram-positives. [ABSTRACT FROM AUTHOR]

• First long-term daily soil NO flux measurement with an automated system from a temperate forest in Northeast China. • Soil temperature explained 90–92% of the seasonal variation in NO emission, with a Q 10 of 3.67. • The optimum soil moisture for NO emission was 37% WFPS during the growing season. • Annual soil NO emission was 0.42±0.04 kg N ha−1, being 31% of the global forest average. • Soil NO emission during the non-growing season was only 7.7% of the annual flux. Nitric oxide (NO) is a highly reactive trace gas affecting atmospheric chemistry and air quality. Although forest soils have been recognized as an important source of atmospheric NO, there are large uncertainties in global forest soil NO emission inventories (ranged from 0.03 to 8.00 kg N ha−1, averaged 1.34 ± 0.28 kg N ha−1), partly due to the paucity of high-frequency monitoring from unmanaged forests. In this study, we used an automated sampling system to measure NO fluxes with a high temporal resolution over two years (daily measurements from January 2019 to December 2020) in a mixed forest in Northeast China. We found that the mean annual NO emission was 0.42 ± 0.04 kg N ha−1, being 31% of the global forest average. The contribution of NO emission during the growing season was 92% of the yearly NO flux. Soil temperature was the most important edaphic factor in regulating NO emission, explaining 90–92% of the seasonal variation. The apparent temperature sensitivity (Q 10) of NO flux was 3.67. In the growing season, NO emission was also influenced by soil moisture, with optimum soil moisture of 37% WFPS. By providing a detailed measurement of diurnal, seasonal, and annual dynamics of NO emissions and their environmental controls from forest soils, our data are useful to develop more accurate biogeochemical models that will improve upscaled global NO budgets. [ABSTRACT FROM AUTHOR]

Plant roots are the primary source of soil organic carbon (C) and critically support the growth and activities of microbes in the rhizosphere. Climate change factors may, however, modify root-microbial interactions and impact C dynamics in the rhizosphere. Yet, the direction and magnitude of interactive climate change effects, as well as the underlying mechanisms, remain unclear. Here we show evidence from a field experiment demonstrating that warming and precipitation changes strengthen root controls over litter decomposition in a semi-arid grassland. While warming and precipitation reduction suppressed microbial decomposition of root litter regardless of the root presence, precipitation increase stimulated litter decomposition only in the absence of roots, suggesting that plant competition for water constraints the activities of saprophytic microbes. Root presence increased microbial biomass but reduced microbial activities such as respiration, C cycling enzymes and litter decomposition, indicating that roots exert differential effects on microbes through altering C or water availability. In addition, nitrogen (N) input significantly reduced microbial biomass and microbial activities (respiration). Together, these results showed that alterations in soil moisture induced by climate change drivers critically modulate root controls over microbial decomposition in soil. Our findings suggest that warming-enhanced plant water utilization, combined with N-induced suppression of microbes, may provide a unique mechanism through which moderate increases in precipitation, warming and N input interactively suppress microbial decomposition, thereby facilitating short-term soil C sequestration in the arid and semi-arid grasslands. • Climate change effects on root decomposition were studied in a semi-arid grassland. • Soil moisture dominated microbial responses to climate change drivers. • Root presence shifts limitation to microbes from labile C to water availability. • Roots increase microbial biomass but suppress microbial decomposing activities. [ABSTRACT FROM AUTHOR]