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The activation of cyclic GMP‐AMP (cGAMP) synthase (cGAS) and its adaptor, stimulator of interferon genes (STING), is known to reprogram the immunosuppressive tumor microenvironment for promoting antitumor immunity. To enhance the efficiency of cGAS‐STING pathway activation, macrophage‐selective uptake, and programmable cytosolic release are crucial for the delivery of STING agonists. However, existing polymer‐ or lipid‐based delivery systems encounter difficulty in integrating multiple functions meanwhile maintaining precise control and simple procedures. Herein, inspired by cGAS being a natural DNA sensor, a modularized DNA nanodevice agonist (DNDA) is designed that enable macrophage‐selective uptake and programmable activation of the cGAS‐STING pathway through precise self‐assembly. The resulting DNA nanodevice acts as both a nanocarrier and agonist. Upon local administration, it demonstrates the ability of macrophage‐selective uptake, endosomal escape, and cytosolic release of the cGAS‐recognizing DNA segment, leading to robust activation of the cGAS‐STING pathway and enhanced antitumor efficacy. Moreover, DNDA elicits a synergistic therapeutic effect when combined with immune checkpoint blockade. The study broadens the application of DNA nanotechnology as an immune stimulator for cGAS‐STING activation. [ABSTRACT FROM AUTHOR]

Dark carbon fixation (DCF), through which chemoautotrophs convert inorganic carbon to organic carbon, is recognized as a vital process of global carbon biogeochemical cycle. However, little is known about the response of DCF processes in estuarine and coastal waters to global warming. Using radiocarbon labelling method, the effects of temperature on the activity of chemoautotrophs were investigated in benthic water of the Yangtze estuarine and coastal areas. A dome‐shaped thermal response pattern was observed for DCF rates (i.e., reduced rates at lower or higher temperatures), with the optimum temperature (Topt) varying from about 21.9 to 32.0°C. Offshore sites showed lower Topt values and were more vulnerable to global warming compared with nearshore sites. Based on temperature seasonality of the study area, it was estimated that warming would accelerate DCF rate in winter and spring but inhibit DCF activity in summer and fall. However, at an annual scale, warming showed an overall promoting effect on DCF rates. Metagenomic analysis revealed that the dominant chemoautotrophic carbon fixation pathways in the nearshore area were Calvin‐Benson‐Bassham (CBB) cycle, while the offshore sites were co‐dominated by CBB and 3‐hydroxypropionate/4‐hydroxybutyrate cycles, which may explain the differential temperature response of DCF along the estuarine and coastal gradients. Our findings highlight the importance of incorporating DCF thermal response into biogeochemical models to accurately estimate the carbon sink potential of estuarine and coastal ecosystems in the context of global warming. [ABSTRACT FROM AUTHOR]

Hydroxylamine (NH2OH) is an important intermediate of nitrification and can contribute to nitrous oxide (N2O) production through abiotic and biotic pathways. NH2OH concentrations and associated biogeochemical controls in estuarine water and sediments remain poorly understood. Here, we investigated spatial and seasonal variability of NH2OH concentrations in water and sediments and determined the correlation between NH2OH and N2O in the Min River Estuary off southeast China. NH2OH concentrations in water and sediments ranged from 0.22 to 140 nmol N L−1 and from 0.17 to 9.22 μmol N kg−1, respectively. High differences in NH2OH concentrations between sediments and water could drive diffusion of NH2OH from sediments to water. NH2OH concentrations were significantly higher in warm than in cold seasons, suggesting that NH2OH production is highly dependent on temperature. Upper estuary (urban section) showed higher NH2OH concentrations in water and sediments, followed by lower and middle estuary. Temperature, dissolved oxygen, and pH were the major factors driving spatial and seasonal variability in NH2OH concentrations. Water dissolved N2O concentrations and air‐water N2O fluxes varied between 1.52 and 55.9 nmol N L−1 and between −57.7 and 78.7 nmol N m−2 h−1, respectively, with switches from net sinks in spring to net sources of N2O emissions in other seasons. Although N2O concentrations and fluxes were linearly correlated with water NH2OH concentrations, the contribution of NH2OH to N2O production could not be addressed. Therefore, the dynamics of NH2OH concentrations are a useful tool to assess potential production and consumption pathways of N2O in estuarine and coastal ecosystems. Plain Language Summary: Hydroxylamine (NH2OH) can produce nitrous oxide (N2O) through abiotic and biological processes in estuarine and coastal environments. This study investigated seasonal and spatial variability of NH2OH concentrations in water and sediments and determined the correlation between N2O and NH2OH concentrations in the Min River Estuary off southeast China. NH2OH concentrations in water and sediments varied significantly across the seasons and along this estuary, with higher concentrations in warm seasons and in upper estuary. High temperature could cause low dissolved oxygen and low pH that stimulate nitrification to produce more NH2OH and NO2−, which increased NH2OH oxidation and nitrifier‐denitrification to yield more N2O. N2O concentrations and fluxes were significantly related to NH2OH concentrations, suggesting that NH2OH could be a relevant source of N2O emissions. This study shows the effect of NH2OH production in the emissions of N2O, providing insights which can be used to better constrain the projections on future emissions of this gas in estuarine environments. Key Points: Hydroxylamine concentrations in water and sediments were significantly higher in warm than in cold seasonsAmmonium and temperature were the major drivers of spatiotemporal variability in hydroxylamine concentrationsHydroxylamine and nitrous oxide concentrations in water and sediments were strongly correlated [ABSTRACT FROM AUTHOR]

The importance of dissolved organic matter (DOM) and methanogenic community to methane (CH4) production in estuarine benthic sediments remains poorly understood. Here, we determined CH4 production rate, DOM molecule, and methanogenic community in benthic sediments of Min River Estuary. CH4 production rates in freshwater and saline sediments varied between 0.28 and 0.56 μg CH4 m−2 h−1, and between 0.17 and 0.27 μg CH4 m−2 h−1, respectively. CH4 production rates in freshwater sediments were increased by 36%–66% under saline incubation, compared to freshwater incubation, indicating that elevated salinity can stimulate CH4 production. The δ13C‐CH4 decreased and fractionation factor between δ13C‐CO2 and δ13C‐CH4 increased from high‐ to low‐OM sediments, suggesting a shift of CH4 production from acetoclastic to hydrogenotrophic pathways. A decrease in labile fractions and an increase in recalcitrance fractions of DOM were accompanied by the decrease in CH4 production. The Methanoregula, Methanocellales, Methanosarcina, and Methanosaeta were the predominant methanogenic communities in mediating CH4 production. The differences in DOM molecules and methanogenic archaea taxa could drive the distinct CH4 production rates in estuarine benthic sediments. These results suggest that DOM quantity and molecules and methanogenic archaea can substantially affect CH4 production, which have broader implications for global CH4 estimates under the ongoing eutrophication in estuarine and coastal ecosystems. Plain Language Summary: Dissolved organic matter (DOM) is important to methane (CH4) production in benthic sediments via mediating DOM structure and methanogenic archaea. This study determined CH4 production rates, DOM molecules and methanogenic communities in estuarine benthic sediments spanning the gradient of OM contents. The results indicated that the increases in labile fractions of DOM and elevated salinity could trigger benthic CH4 production. Interestingly, methanogenic archaea abundance decreased strongly under the decline of DOM quantity, and was significantly higher in freshwater than in saline sediments. Aceticlastic methanogenesis dominated CH4 production in benthic sediments with more labile fractions of DOM, whereas the recalcitrant fractions with high aromaticity and molecular size contributed dominantly to hydrogenotrophic methanogenesis. These findings highlight the crucial role of DOM molecule and quantity in driving methanogenesis pathways and methanogenic archaea communities in estuarine benthic sediments and underline that eutrophication may accelerate carbon outgassing and global climate warming in the Anthropocene. Key Points: High labile fractions of dissolved organic matter (DOM) favored acetoclastic pathway of methane productionInterspecies co‐occurrence network structure of methanogens was more complex in saline than in freshwater sedimentsDOM quantity and molecule composition drove distinct methanogens taxa and methane production [ABSTRACT FROM AUTHOR]

How the partitioning between dissimilatory nitrate reduction to ammonium (DNRA) and N2 production responds to hypoxia in seasonally hypoxic estuaries has not been well understood. In this study, 15N tracer incubations were used to investigate benthic denitrification, anammox and DNRA rates for three years (2016–2018) across seasonally hypoxic areas off the Changjiang Estuary. Dissolved oxygen contents in bottom water were significantly lower in July than in February/March. Concentrations of NH4+ and NOx– in bottom water throughout the sampling sites did not vary between seasons. Rates of benthic denitrification (0.45–6.55 nmol N g−1 h−1), anammox (0.02–0.30 nmol N g−1 h−1) and DNRA (0.06–0.59 nmol N g−1 h−1) varied largely along the estuary. Denitrification, anammox and DNRA rates did not vary significantly between inshore and offshore sites. However, denitrification rates were significantly lower and DNRA rates were significantly higher in consistently than transiently hypoxic sites. Anammox rates were slightly lower in consistently than transiently hypoxic sites. Ratios of DNRA to N2 production were in a range of 0.015–0.53, and were significantly higher in consistently than transiently hypoxic sites, but did not vary significantly between inshore and offshore sites. The lower temperature sensitivity of denitrification and anammox compared to their Q10 values further indicated that hypoxia may inhibit N2 production. These results suggest that high incidence hypoxia can decrease denitrification and anammox rates but increase DNRA rates with important implications on N retention versus removal, thereby exacerbating eutrophication and hypoxia in estuarine and coastal environments. Plain Language Summary: This study investigated benthic denitrification, anammox and dissimilatory nitrate reduction to ammonium (DNRA) rates for three years (2016–2018) across the consistently and transiently hypoxic areas off the Changjiang Estuary. Denitrification rates were significantly lower, whereas DNRA rates were significantly higher in consistently than transiently hypoxic sites. Anammox rates were slightly lower in consistently than transiently hypoxic sites. The ratios of DNRA to N2 production (including denitrification and anammox) were significantly higher in consistently than transiently hypoxic sites, but did not vary significantly between inshore and offshore sites. Therefore, it is concluded that high incidence hypoxia can decrease N2 production but facilitate nitrogen retention, which may further exacerbate eutrophication and hypoxia in estuarine and coastal environments. Key Points: Denitrification dominated over anammox and dissimilatory nitrate reduction to ammonium (DNRA) throughout the sampling seasons and sitesDenitrification and anammox rates were lower, whereas DNRA rates were higher in consistently than transiently hypoxic sitesHigh incidence hypoxia favored N recycling rather than N removal off the Changjiang Estuary [ABSTRACT FROM AUTHOR]

Background: Alterations in body compositions are related to poor outcomes and the presence of complications in cirrhosis. However, no predictive tools combining all these anthropometric parameters are applicable in the clinical setting. We aimed to clarify the potential utility of body compositions and develop a nomogram incorporating any independent factor for prognosticating long-term mortality in cirrhosis.Methods: A total of 414 patients were randomized into primary (n = 274) and validation (n = 140) cohorts. X-tile was performed to identify optimal cut points for stratifying participants. Multivariate Cox regression was performed, and nomogram incorporating body compositions were generated. The utility of developed models was evaluated by Harrell concordance index (C-index), calibration curve, and decision curve analysis (DCA).Results: Stratifying by X-tilederived cut points, low skeletal muscle index (myopenia), high intramuscular adipose tissue content (myosteatosis), and the ratio of high visceral to subcutaneous adipose tissue area (adiposity) was independently associated with 3-year mortality. A sex-stratified nomogram incorporating anthropometric indices and clinical factors resulted in moderate discriminative accuracy, with a C-index of 0.787 (95% CI, 0.736-0.838) and 0.789 (95% CI, 0.727-0.851) in males and females, respectively. The calibration curve showed predictive survival corresponding optimally with the actual outcomes. Our models were feasible in the clinical settings based on DCA. Similar results were observed in the validation cohort. Additionally, participants could be classified into 3 distinct risk groups by the nomogram.Conclusions: Our proposed nomogram embedding body compositions rendered an individualized predictive tool for long-term mortality in cirrhosis. [ABSTRACT FROM AUTHOR]

The median survival time of lower grade glioma (LGG) tumors spans a wide range of 2–10 years and is highly dependent on the molecular characteristics and tumor location. Currently, there is no prognostic predictor for these tumors based on autophagy‐related (ATG) genes. A prognostic risk score model based on the most significant seven ATG genes was established for LGG. These seven genes, including GRID2, FOXO1, MYC, PTK6, IKBKE, BIRC5, and TP73, have been screened as potentially therapeutic targets. The Kaplan–Meier survival curve analyses validated that patients with high or low risk scores had significantly different overall survival. Following the multivariate Cox regression and area under the ROC curve (AUC) analysis, a final prognostic model based on age, World Health Organization grade, 1p19q‐codeletion status, and ATG risk score was performed as an independent prognostic indicator (training set: p = 4.09E−05, AUC = 0.901; validation set‐1: p =.00069, AUC = 0.808; validation set‐2: p =.0376, AUC = 0.830). Subsequently, a prognostic nomogram was constructed for individualized survival prediction. The calibration plots showed excellent predict efficiency between probability and actual overall survival. In this study, we provided several potential biomarkers for further developing potentially therapeutic targets of LGG. We also established a prognostic model and nomogram to improve the clinical glioma management and assist individualized survival prediction. [ABSTRACT FROM AUTHOR]

Aim: It is well known that the use of proton pump inhibitor (PPI) is widespread in patients with liver cirrhosis. PPI counteracts H2 receptor inhibitor (H2RA) with its strong acid suppression effect. However, there is always a concern that PPI use may increase spontaneous bacteria peritonitis (SBP) development in cirrhotic patients. We aimed to investigate the association between acid suppression therapy (i.e. PPI or H2RA) and SBP through meta‐analysis. Methods: We searched PubMed, Medline, Web of Science, Cochrane library, and Embase for relevant studies published up to April 2019. Pooled OR and 95% CI were calculated by a random‐effects model. Funnel plots and Egger's tests were performed for the evaluation of publication bias. Non‐parametric "trim‐and‐fill" tests were conducted for sensitivity analysis. Results: A total of 20 original articles including 9566 cirrhotic patients were analyzed. The overall meta‐analysis highlighted that PPI use was associated with the risk of SBP (pooled OR 1.77, 95% CI 1.49–2.11). The conclusion was irrespective of study methods, whereas the result was inconsistent only in South America. However, the conclusion might not be stable enough and should be extrapolated with caution. Unlike PPI, we found H2RA was not associated with SBP (pooled OR 1.06, 95% CI 0.75–1.48). Conclusions: In conclusion, PPI use, but not H2RA, will increase the incidence of SBP in cirrhotic patients. In addition, H2RA might be beneficial for patients who require long‐term acid suppression therapy. [ABSTRACT FROM AUTHOR]

Seismic performance is of paramount importance for structures in regions with high seismic risk. Engineered cementitious composite (ECC) exhibits tensile strain hardening behavior and excellent crack dispersion capacity, as well as good workability. The application of ECC material may be a feasible way to improve the seismic behavior of engineering structures. This paper presents a comprehensive review of experimental and simulation studies concerning seismic behavior of reinforced ECC members and reinforced concrete/ECC composite members. The review is mainly focused on design programs for structural members and their seismic response behavior. The effectiveness of the application of ECC for seismic improvement is discussed. Several design recommendations are provided, based on comparison of the related studies. [ABSTRACT FROM AUTHOR]

Bonding between rebar and steel fiber reinforced concrete (SFRC) has a major effect on reinforced SFRC members exposed to chloride environments where both steel fiber and reinforcement are subjected to corrosion damage. This paper presents an experimental study of the effect of corrosion on the bond behavior of reinforcement and SFRC. The test parameters include corrosion ratio, fiber fraction, and cover thickness‐rebar diameter ratio (c/d). Failure patterns, bond‐slip curves, and bond strength were compared. Increasing fiber fraction and c/d ratio enhanced bond strength and residual bond strength through improved confinement by the surrounding SFRC. With increasing corrosion, bond strength at first retained its initial strength or increased slightly and then reduced at corrosion ratios beyond 6–8.88%. A bond strength model is proposed which considers the combined effect of corrosion ratio, fiber fraction, and c/d ratio. [ABSTRACT FROM AUTHOR]

Background & Aims: An elevated neutrophil‐to‐lymphocyte ratio (NLR) has received attention as a prognostic surrogate across chronic liver diseases. However, an exact threshold has not been fully elucidated. Methods: A total number of 589 patients with cirrhosis (LC) were included. The value of NLR was calculated and its optimal cut‐off was initially determined by X‐tile program. Independent predictors of 90‐day mortality were identified with Cox regression model. The Kaplan‐Meier method was used to generate survival curves. To reduce influences of selection bias and possible confounders, a 1:2 propensity score matching (PSM) was performed. Results: The X‐tile indicated that the difference in survival was most significant for NLR more than 8.9. Serum NLR > 8.9 was an independent indicator in the entire cohort and PSM subset (HR 4.268, 95% CI 2.211‐8.238, P < .001; HR 4.209, 95% CI 1.448‐12.238, P = .008 respectively). Subgroup analysis showed that NLR > 8.9 was an independent risk factor of 90‐day mortality regardless of age, gender, CTP or MELD score. Conclusions: The value of NLR more than 8.9 is a feasible cut‐off across clinical settings among applicable population. The adding of NLR to other conventional predictive systems has the potential to provide incremental value without extra economic cost. [ABSTRACT FROM AUTHOR]

Self‐compacting concrete (SCC) is a cementitious composite which serves complex formworks without mechanical vibrations with superior deformability and high resistance to segregation. Besides, the recycled aggregate concrete (RAC) is also developing rapidly and along with the ever‐increasing sustainable demand for infrastructure. The combination of the fibers, RAC, and SCC may create advantages for the construction industry. In this study, the polypropylene (PP) fiber at 0.1, 0.15, 0.2, and 0.25% volume fractions and steel fibers at 0.25, 0.5, 0.75, and 1% volume fractions are introduced into fiber‐reinforced recycled aggregate self‐compacting concrete (FR‐RASCC). Both fresh property and hardened mechanical performance, comprising compressive and tensile strengths and modulus of elasticity are analyzed. The fibers validate the optimal 0.1% volume fraction for PP fiber and 0.75% volume fraction for steel fiber. In addition, the results are proved to enhance the mechanical properties and reduce cracking despite the negative impact on the fresh property. Moreover, the experimental outcomes are compared with previous researches to establish the linear model, demonstrating the relationship between fiber fraction and the mechanical properties. [ABSTRACT FROM AUTHOR]

Sympathetic hyperactivity occurs in a subgroup of patients after traumatic brain injury (TBI). The rostral ventrolateral medulla (RVLM) is a key region for the activity of sympathetic nervous system. Oxidative stress in the RVLM is proved to be responsible for the increased level of sympathetic activity in animal models of hypertension and heart failure. In this study, we investigated whether oxidative stress in the RVLM contributed to the development of sympathetic hyperactivity after TBI in rats. Model of diffuse axonal injury was induced using Sprague‐Dawley rats, and level of mean arterial pressure (MAP) and plasma Norepinephrine (NE) was measured to evaluate the sympathetic activity. For the assessment of oxidative stress, expression of reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD) in the RVLM was determined. Microinjection of Tempol into the RVLM was performed to determine the effect of oxidative stress on sympathetic hyperactivity. According to the results, TBI led to elevated MAP and plasma NE in rats. It also induced a significantly increased level of ROS, MDA production and decreased level of SOD in the RVLM. The sympathetic activity, ROS, and MDA in the RVLM decreased significantly after microinjection of Tempol. Therefore, the present results suggested that oxidative stress in the RVLM was involved in the development of sympathetic hyperactivity following TBI. [ABSTRACT FROM AUTHOR]

Dissimilatory nitrate/nitrite reduction processes play an important role in controlling nitrogen loading in river environments. However, the relative importance of climatic temperature regime and biogeochemical controls to dissimilatory nitrate/nitrite reduction processes remains unclear. We used nitrogen isotope tracer approach to investigate geographical variabilities of denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA) in river sediments from temperate to tropical climates of China. Denitrification, anammox, and DNRA varied greatly across the climatic gradient, with potential rates of 1.47–25.7, 0.54–3.4, and 0.15–7.17 nmol N g−1 h−1, respectively. Mean measured rates throughout the sampling sites were 9.73 nmol N g−1 h−1 for denitrification, 1.29 nmol N g−1 h−1 for anammox, and 1.61 nmol N g−1 h−1 for DNRA. Denitrification and DNRA rates increased significantly from temperate to tropical climates, while no significantly spatial difference was observed for anammox rates along the climatic gradient. Mean annual temperature, total organic carbon, dissolved organic carbon, pH, NH4+, NO3–, C/N, Fe2+, and functional genes were the crucial factors affecting denitrification, anammox, and DNRA. High dissolved organic carbon and NO3– availability determined nitrogen removal capacity in river sediments. Mean annual temperature was the most important factor explaining the geographical variances of denitrification and DNRA, while the critical predictor of anammox variance was sediment pH along the climatic gradient. Our results highlight that biogeochemical controls and climatic temperature regime are important coregulators affecting the geographical variabilities of dissimilatory nitrate/nitrite reduction processes in river sediments at the continental‐scale variation. Key Points: Denitrification and DNRA rates increased from temperate to tropical climatesDenitrification, anammox, and DNRA rates correlated with sediment characteristicsTemperature explained mostly variances of denitrification and DNRA, and sediment variables were the critical predictors of anammox variance [ABSTRACT FROM AUTHOR]

Restoring ecosystems has been a key strategy to combat land degradation and reverse losses in biodiversity. Because interactions between communities above and below the ground drive key ecosystem processes, they can profoundly influence ecological succession trajectories. However, relatively little empirical information is available for plant–microbial diversity linkages during ecological restoration. Here, using the Illumina platform for bacterial and fungal sequencing, we investigated linkages between soil microbial and plant diversity across a 30‐year chronosequence of restored grasslands on the Loess Plateau in Northwestern China. The results showed that plant, bacterial, and fungal species richness all increased with increased years of grassland restoration, during which their community compositions shifted among six different habitats. The microbial community assembly data were integrated into a co‐occurrence network analysis, revealing greater network complexity in the late restoration stage (25 and 30 years). The alpha and beta diversities of both the bacterial and fungal communities were significantly and positively correlated with plant communities. Bacterial community composition was governed primarily by soil edaphic factors and deterministic processes, whereas fungal community composition was structured mainly by plant community composition and both deterministic and stochastic processes. This evidence strongly suggests that different ecological processes shaped bacterial and fungal communities during ecological restoration of the grasslands. Our results provide insight into the aboveground–belowground associations of restored habitats, which may have implications for ecological restoration practices and biodiversity maintenance in arid and semiarid grassland ecosystems. [ABSTRACT FROM AUTHOR]

Ammonia oxidation, the first and rate‐limiting step in nitrification, plays a critical role in the nitrogen cycle. However, the links between the dynamics of ammonia‐oxidizing communities and ecosystem processes along the estuarine salinity gradient remain uncertain. In this study, we examined the diversity, abundance, and community structure of ammonia‐oxidizing prokaryotes, and the potential nitrification rates along the Yangtze estuarine salinity gradient. Phylogenetic analysis showed that the predominant ammonia‐oxidizing bacteria (AOB) and ammonia‐oxidizing archaea (AOA) fell within the Nitrosospira and Nitrosopumilus clusters, respectively. The AOB amoA gene abundance (4.67 × 105 to 3.90 × 107 copies per gram of dry sediment) outnumbered AOA (5.14 × 104 to 8.88 × 106 copies per gram of dry sediment). The potential nitrification rates varied between 0.13 and 0.63 μg N·g−1·day−1 and related only to AOA amoA gene abundance. Salinity had significant effects on AOA amoA gene abundance, nitrification rates, and the community structure of ammonia‐oxidizing prokaryotes. Principal coordinate analysis showed that the AOB amoA gene clones derived from the middle‐ and high‐salinity regions behaved as a cohesive group, while all the low‐salinity clone libraries were grouped together. Moreover, the distribution of AOA communities showed a distinct salinity differentiation. Overall, this study improves the understanding of the dynamic shifts in ammonia‐oxidizing microorganisms in the Yangtze Estuary. Key Points: Significant shifts in ammonia‐oxidizing community structure were found along the salinity gradientBoth of AOA amoA gene abundance and potential nitrification rates were significantly and negatively correlated with salinityPotential nitrification rates were significantly related to AOA amoA gene abundance, but not with AOB [ABSTRACT FROM AUTHOR]

Marine benthic nitrogen (N) cycling may vary widely across space and seasons; it is thus needed to make high‐resolution estimations of these important ecosystem processes with a reasonable number of variables. In this study, we determined the benthic denitrification and anammox potentials in two basins, the Bohai Sea and the North Yellow Sea of China in May and November, and evaluated models in predicting these functions with environmental factors and/or microbial gene‐based functional traits. We found that denitrification generally dominated the N loss (54–98%), and that the denitrification rate varied greatly between basins and seasons. The anammox rate was generally higher in the Bohai Sea than in the North Yellow Sea in both seasons, and it made a greater contribution in November (22%) than in May (16%). Among the measured environmental factors, chlorophyll a in bottom waters and sedimentary organic carbon content were the most influential for predicting denitrification and anammox rates, respectively. On the other hand, the alpha diversities and gene abundances of involved bacteria were poorly correlated with the function potentials, indicating that these functional traits could not well explain the functions alone. Upon the incorporation of two gene copy number ratios [nosZ/(nirS + nirK) and nirK/bacterial 16S rRNA genes] into the environmental factor‐parameterized models, however, we found that the predictive powers of the regression models for total N loss, denitrification and anammox rates, and contributions of anammox increased substantially, indicating that taking microbial functional traits into account could make estimations of these N‐cycling functions in coastal ecosystems more accurate. Key Points: Benthic N2 productions via denitrification and anammox varied greatly across seasons and at a basin‐wide scaleBottom water chlorophyll a and sediment organic carbon were the main environmental factors underlying the biogeography of benthic N lossAdding proper functional traits into models improved the predictability for benthic denitrification and anammox functions [ABSTRACT FROM AUTHOR]

Abstract: Nitrogen fixation is a microbial‐mediated process converting atmospheric dinitrogen gas to biologically available ammonia or other molecules, and it plays an important role in regulating nitrogen budgets in coastal marine ecosystems. In this study, nitrogen fixation in the intertidal sediments of the Yangtze Estuary was investigated using nitrogen isotope tracing technique. The abundance of nitrogen fixation functional gene (nifH) was also quantified. The measured rates of sediment nitrogen fixation ranged from 0.37 to 7.91 nmol N g−1 hr−1, while the abundance of nifH gene varied from 2.28 × 106 to 1.28 × 108 copies g−1 in the study area. The benthic nitrogen fixation was correlated closely to the abundance of nifH gene and was affected significantly by salinity, pH, and availability of sediment organic carbon and ammonium. It is estimated that sediment nitrogen fixation contributed approximately 9.3% of the total terrigenous inorganic nitrogen transported annually into the Yangtze estuarine and coastal environment. This result implies that the occurrence of benthic nitrogen fixation acts as an important internal source of reactive nitrogen and to some extent exacerbates nitrogen pollution in this aquatic ecosystem. [ABSTRACT FROM AUTHOR]

Global reactive nitrogen (N) has increased dramatically in coastal marine ecosystems over the past decades and caused numerous eco-environmental problems. Coastal marine sediment plays a critical role in N losses via denitrification and anaerobic ammonium oxidation (anammox) and release of nitrous oxide (N2O). However, both the magnitude and contributions of denitrification, anammox, and N2O production in sediments still remain unclear, causing uncertainty in defining the N budget for coastal marine ecosystems. Here potential rates of N losses, and their contributions and controlling factors, were investigated in surface sediments during six cruises from 429 sites of the East China Sea. The potential rates of denitrification, anammox, and N2O production varied both spatially and seasonally, but the contribution of anammmox to total N2 production (%anammox) and N2O:N2 ratio only varied spatially. Both organic carbon and nitrate (NO3−) were important factors controlling N losses, N2O:N2 ratio, and %anammox. Our results also showed that marine organic carbon induced by eutrophication plays an important role in stimulating reactive N removal and increasing N2O production in warm seasons. The sediment N loss caused by denitrification, anammox, and N2O production in the study area were estimated at 2.2 × 106 t N yr−1, 4.6 × 105 t N yr−1, and 8 × 103 t N yr−1, respectively. Although sediments remove large quantities of reactive N, they act as an important source of N2O in this region influenced by NO3−-laden rivers. [ABSTRACT FROM AUTHOR]

Vascular endothelial growth factor ( VEGF) is a secreted mitogen associated with angiogenesis. VEGF has long been thought to be a potent neurotrophic factor for the survival of spinal cord neurons. However, the role of VEGF in the regulation of ischemic brain injury remains unclear. In this study, rats were subjected to MCAO (middle cerebral artery occlusion) followed by intraperitoneal injection of VEGF165 (10 mg/kg) immediately after surgery and once daily until the day 10. The expression of target genes was assayed using qPCR, western blot and immunofluorescence to investigate the role of VEGF165 in regulating ischemic brain injury. We found that VEGF165 significantly inhibited MCAO-induced up-regulation of Scavenger receptor class A ( SR-A) on microglia in a VEGFR1-dependent manner. VEGF165 inhibited lipopolysaccharide (LPS)-induced expression of proinflammatory cytokines IL-1β, tumor necrosis factor alpha ( TNF-α) and iNOS in microglia. More importantly, the role of VEGF165 in inhibiting neuroinflammation is partially abolished by SR-A over-expression. SR-A further reduced the protective effect of VEGF165 in ischemic brain injury. These data suggest that VEGF165 suppresses neuroinflammation and ischemic brain injury by inhibiting SR-A expression, thus offering a new target for prevention of ischemic brain injury. [ABSTRACT FROM AUTHOR]

Dissimilatory nitrate reduction to ammonium (DNRA) plays an important role in regulating the fate of reactive nitrogen in estuarine and coastal ecosystems. In this work, intertidal sediments of the Yangtze Estuary were collected in January and August 2015. Potential rates of DNRA and associated functional gene were investigated with nitrogen isotope-tracing and molecular techniques. The measured DNRA rates ranged from 0.14 to 5.57 μmol 15N kg−1 h−1 in the intertidal sediments. DNRA rates were tightly related to abundance of nrfA gene ( p < 0.001), demonstrating that fermentation reaction may be the dominant pathway of DNRA in the study area. Redundancy analysis (RDA) showed a relationship between DNRA and organic matter and NO2−, suggesting that these substrates stimulated the metabolism of DNRA microorganisms. On the other hand, the correlation between abundances of nrfA gene and Fe2+ and sulfide in the RDA analysis implied that oxidation of both Fe2+ and sulfide can enhance fermentative DNRA by providing extra free energy. DNRA converted approximately 2.29 × 105 t of nitrate to ammonia annually in the sampling area of the Yangtze Estuary, and most of the converted ammonium was retained in the estuarine ecosystem. DNRA may further contribute to eutrophication in the Yangtze Estuary and also in the other hypereutrophic estuaries. [ABSTRACT FROM AUTHOR]

Melatonin functions as a crucial mediator of sterile neuroinflammation; however, the underlying mechanisms remain poorly understood. Dysfunctional mitochondria, a main source of reactive oxygen species, are impacted in inflammation activation. This study aimed to examine the effect of melatonin on inflammation via elimination of damaged mitochondria after controlled cortical impact, an in vivo model of traumatic brain injury ( TBI). Here, we demonstrated that inhibition of mitophagy, the selective degradation of damaged mitochondria by autophagy, markedly enhanced inflammation induced by TBI. Melatonin treatment activated mitophagy through the mTOR pathway, then to attenuate TBI-induced inflammation. Furthermore, treatment with melatonin significantly ameliorated neuronal death and behavioral deficits after TBI, while 3-methyladenine reversed this effect by inhibiting mitophagy. Taken together, these results highlight a role for melatonin in protecting against TBI-triggered immunopathology, which is accomplished by negatively regulating inflammation activation and IL-1 β secretion via the autophagy of damaged mitochondria. [ABSTRACT FROM AUTHOR]