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Acetaminophen (APAP) overdose is the most common driver of drug-induced liver injury (DILI) worldwide, and the gut microbiome plays a crucial role in this process. In this study, we estimated the effect of Bifidobacterium longum R0175 on APAP-induced liver injury in mice and discovered that B. longum R0175 alleviated liver injury by diminishing inflammation, reducing oxidative stress levels, inhibiting hepatocyte death and improving APAP-induced microbiome dysbiosis. Further studies revealed that the antioxidative effects of B. longum R0175 were primarily due to activation of the Nrf2 pathway, which was supported by the Nrf2 pathway inhibitor ML385 counteracting these ameliorative effects. B. longum R0175 modified intestinal metabolites, especially the key metabolite sedanolide, which could activate the Nrf2 pathway and contribute to the protective effects against APAP-induced liver injury. Moreover, we found that sedanolide exhibited close interrelationships with specific microbial taxa, indicating that this factor may be derived from gut microbes. In conclusion, our work demonstrated that B. longum R0175 could reduce oxidative damage, inflammation and hepatocyte death by activating the Nrf2 pathway. Importantly, we identified the microbiota-derived metabolite sedanolide, which was first discovered in the mouse intestine, as a key agonist of the Nrf2 pathway and primary effector of B. longum R0175 in APAP challenge. These findings provide new perspectives for APAP overdose therapy and demonstrate the enormous potential of B. longum R0175 in alleviating acute liver injury. [Display omitted] • B. longum R0175 alleviated APAP-induced liver injury by diminishing inflammation, oxidative stress levels and hepatocyte death. • B. longum R0175 modified key metabolite sedanolide which could activate the Nrf2 pathway and exert protective effects. • Sedanolide was identified as a microbiota-derived metabolite for its correlation with specific microbes. [ABSTRACT FROM AUTHOR]

Rivers play a significant role in the global nitrous oxide (N 2 O) budget. However, the microbial sources and sinks of N 2 O in river systems are not well understood or quantified, resulting in the prolonged neglect of nitrification. This study investigated the isotopic signatures of N 2 O, thereby quantifying the microbial source of N 2 O production and the degree of N 2 O reduction in the Yellow River. Although denitrification has long been considered to be the dominant pathway of N 2 O production in rivers, our findings indicated that denitrification only accounted for 18.3% (8.2%–43.0%) of the total contribution to N 2 O production in the Yellow River, with 50.2%–80.2% being concurrently reduced. The denitrification contribution to N 2 O production (R2 = 0.44, p < 0.01) and N 2 O reduction degree (R2 = 0.70, p < 0.01) were positively related to the dissolved organic carbon (DOC) content. Similar to urban rivers and eutrophic lakes, denitrification was the primary process responsible for N 2 O production (43.0%) in certain reaches with high organic content (DOC = 5.29 mg/L). Nevertheless, the denitrification activity was generally constrained by the availability of electron donors (average DOC = 2.51 mg/L) throughout the Yellow River basin. Consequently, nitrification emerged as the primary contributor in the well-oxygenated Yellow River. Additionally, our findings further distinguished the respective contribution of ammonia-oxidizing bacteria (AOB) and archaea (AOA) to N 2 O emissions. Although AOB dominated the N 2 O production in the Yellow River, the AOA specie abundance (AOA/(AOA + AOB)) contributed up to 32.6%, which resulted in 25.6% of the total nitrifier-produced N 2 O, suggesting a significant occurrence of AOA in the oligotrophic Yellow River. Overall, this study provided a non-invasive approach for quantifying the microbial sources and sinks to N 2 O emissions, and demonstrated the substantial role of nitrification in the large oligotrophic rivers. [Display omitted] • Nitrification was the primary contributor to N 2 O in the well-oxygenated Yellow River. • DOC content determined the denitrification activity and N 2 O reduction degree. • Denitrification was generally constrained by electron donors in the Yellow River. • 50.2%–80.2% N 2 O was reduced to N 2 in the Yellow River. The quantification of the microbial sources to N 2 O emissions highlights the important role of nitrification to N 2 O emission in large rivers. [ABSTRACT FROM AUTHOR]

Robot comprehensive performance optimization is a high dimensional non-convex problem, which is of great significance in the practice of robotic intelligent manufacturing. Existing methods still face many challenges in performance evaluation, local optima, and planning efficiency. In this paper, a novel method based on accelerated gradient descent and directed-mutagenesis genetic algorithm (AGD-DGA) is proposed for efficient robotic motion planning and comprehensive performance optimization. Firstly, the time, energy consumption, and impact (T-E-I) are taken as the optimization objectives. In particular, the power loss sub-model is constructed, which is rarely considered in the previous research on motion optimization, and it is combined with the driving power sub-model to improve the evaluation accuracy. Next, a novel directed-mutagenesis genetic algorithm (DGA) is proposed to address the local optima problem. Compared with existing methods based on random sampling, the DGA further improves the success rate and efficiency by updating the probability model based on the adaptive Gaussian process. Moreover, a hierarchical weight updating mechanism is established to overcome the impact of additional performance indicators on the success rate of collision-free path planning. To improve planning efficiency, an incremental optimization mechanism and an adaptive fine-tuning strategy for population size are proposed to reduce unnecessary sampling, evaluation, and sorting. The simulation and experimental results in different scenarios demonstrate that the proposed AGD-DGA achieves better results than most of the mainstream algorithms in terms of optimization efficiency, success rate, and motion performance. In addition, it is also verified that the modified energy consumption model can achieve an average evaluation accuracy of more than 90% while maintaining the calculation efficiency. [ABSTRACT FROM AUTHOR]

Nitrate pollution in fresh water is becoming increasingly serious. In this study, the effects of temperature and graphene oxide materials on the potential functions of denitrification communities in lake sediments were investigated by metagenome. The addition of graphene oxide significantly affected the abundance of denitrification genes such as Nap , Nos , and enhanced the contribution of Pseudomonas , making low temperature and material addition conducive to the denitrification process. Module network implied that low temperature increased the centrality of denitrification in community functions. At low temperatures, graphene oxide enhanced community anabolism by stimulation organic carbon consumption and regulating the gene abundance in the citric acid cycle and the semi-phosphorylation Entner-Doudoroff, thus possibly stimulating extracellular polymeric substances (EPS) synthesis and secretion. In addition, graphene oxide may also regulate the transfer of reducing electrons from NADH to denitrifying enzymes by affecting the gene abundances of complex I and complex IV. [Display omitted] • Graphene oxide led to an increase in the proportion of denitrification genes at 8 °C. • Graphene oxide enhanced community anabolism at 8 °C. • Graphene oxide stimulated EPS synthesis and secretion at 8 °C. • Graphene oxide regulated the transfer of electrons to denitrifying enzymes. [ABSTRACT FROM AUTHOR]

Abstract The combined effects of aging and low temperature, long time heating (LTLT) on meat toughness were investigated. Pork loins were heated at 53 or 58 °C for up to 20 h, and shear force values, cooking loss, moisture content, collagen solubility, electrophoresis of myofibrillar proteins were determined. Structural changes in perimysium were also observed by light microscopy and scanning electron microscopy (SEM). Results showed that aging and LTLT cooking independently affected meat toughness, and higher temperature or longer time were required to decrease toughness of one-day aged meat to the same level as in 10-day aged meat. Collagen solubilization is suggested as the main reason for the tenderization effect of LTLT. Myofibrillar proteolysis might not occur during LTLT cooking, and will not be contributing to meat tenderness. [ABSTRACT FROM AUTHOR]

Abstract In this study, the spatial and seasonal bacterioplankton community dynamics were investigated in the main channel of the Middle Route of the South-to-North Water Diversion Project (MRP) using Illumina HiSeq sequencing. Water samples were collected in spring and summer from south to north at eight water quality monitoring stations, respectively. The results showed that seasonal changes had a more pronounced effect on the bacterioplankton community compositions (BCCs) than spatial variation. The diversity analysis results indicated that samples of summer have more operational taxonomic units (OTUs), higher richness and diversity than those in spring. The main phyla, Proteobacteria , Actinobacteria , Bacteroidetes , Cyanobacteria and Chloroflexi , displayed significant differences (P < 0.05) between spring and summer in the main channel. The Redundancy analysis (RDA) targeting all samples indicated that specific conductivity (SPC), dissolved oxygen (DO), pH and temperature (T) might be key factors in driving BCCs, while trophic status showed no significant correlation (P > 0.05). The present study provides important insights into the potential ecological roles of specific taxa in the new artificial ecosystem and it offers reference for studies on ecosystem succession of other giant interbasin water diversion project in the world. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Adding an external source under low C/N can significantly improve nitrogen removal efficiency. • N transformation processes were coupled at the functional genes level. • The vertical distribution of the microbial community in CWs was a remarkable discrepancy. • Adding rice husk as a carbon source could be conducive to the complete nitrification process. Abstract The effect of adding rice husk as an electron donor on the genetic and metabolic diversity of denitrifying communities in a long-term flooded constructed wetland (D1) was compared with the control group without external carbon source addition (D2). The underlying molecular mechanisms responsible for nitrate removal were quantified under different nitrate loading rates. The results showed that D1 achieved higher and more stable removal efficiencies for NO 3 −-N (90–97%) and total nitrogen (73–87%) under different nitrate loading rates, which were approximately 10 times higher than those of D2. This corresponded with much higher absolute abundances of bacterial and nitrogen functional genes in D1 than D2. Additionally, the vertical distribution of microbial communities in D1 and D2 showed significant differences. This pattern suggested that adding rice husk in flooded CWs had beneficial effects on the denitrifying community. Quantitative response relationships and network analysis indicated that denitrification was the dominant nitrogen removal pathway. Moreover, the present study indicated that using rice husk as an external carbon source could be conducive to completing the nitrification process, which was first confirmed at the molecular level. The present study indicated that using rice husk as an external carbon source can significantly enhance denitrification rates and thus improve nitrogen removal in CWs for wastewater treatment process. [ABSTRACT FROM AUTHOR]

The dominance of different nitrate-reducing pathways determines nitrogen cycling patterns. Denitrification (DNF) has been widely studied, but assimilatory nitrate reduction (ANR) and dissimilatory nitrate reduction to ammonium (DNRA) have received much less attention. Their ecological patterns and responsible microbes are poorly understood. Here, we studied the structure and function succession of the three functional groups in the middle route of the South-to-North Water Diversion Project, which is a 1230 km canal spanning 8 degrees of latitude. The results reflected a nitrogen-removing pattern dominated by DNF in the summer and a nitrogen-retaining pattern dominated by ANR and DNRA in the winter. Stenotrophomonas , a typical denitrifier, was the keystone species in the summer and contributed to N 2 O production. Clostridium , a genus able to conduct ANR and DNRA, was the keystone species in the winter. Notably, a significant zonation pattern was discovered. According to the community structure, the system could be separated into two biogeographic zones, and the Yellow River (about latitude 35°N) is an important cut-off line. This bacterial biogeography followed different water characteristics and ecological processes. ANR was found to be an important process and seasonally transformed its habitat from the northern zone to the southern zone. DNRA bacteria were acclimated to the northern zone and favored at this region in both seasons. The generation of N 2 O, a strong greenhouse gas, also exhibited this zonation pattern. This is the first study to consider assimilatory and dissimilatory nitrate reducers together at a molecular level, and provides new insights into the underlying patterns of a nitrate-reducing bacterioplankton community. [ABSTRACT FROM AUTHOR]

[Display omitted] • Iron-based denitrification improved nitrogen removal at low C/N ratio in freshwaters. • Microbially mediated denitrification dominated rather than chemodenitrification. • Five fast-growing microbes accounted for over 99% of the community. • Amino acids and vitamins needed by an organism could be satisfied by another member. • The two-partner relationships increased community stability without limiting activity. Iron-dependent denitrification is a safe and promising technology for nitrogen removal in freshwaters. However, the understanding of microbial physiology and interactions during the process was limited. Denitrifying systems inoculated with freshwater samples were operated with and without iron(II) at a low C/N ratio for 54 days. Iron addition improved nitrogen removal. Batch experiments confirmed that microbially mediated reaction rather than abiotic reaction dominated during the process. Metagenomics recovered genomes of the five most abundant microorganisms, which accounted for over 99% of the community in every triplicate of the iron-based system. Based on codon usage bias, all of them were fast-growing organisms. The total abundance of fast-growing organisms was 38% higher in the system with iron than in the system without iron. Notably, the most abundant organism Diaphorobacter did not have enzymes for asparagine and aspartate biosynthesis, whereas Rhodanobacter could not produce serine and cobalamin. Algoriphagus and Areminomonas lost synthesis enzymes for more amino acids and vitamins. However, they could always obtain these growth-required substances from another microorganism in the community. The two-partner relationship minimized the limitation on microbial reproduction and increased community stability. Our results indicated that iron addition improved nitrogen removal by supplying electron donors, promoting microbial growth, and building up syntrophic interactions among microorganisms with timely communications. The findings provided new insights into the process, with implications for freshwater remediation. [ABSTRACT FROM AUTHOR]

• A novel three-term conjugate-like descent SMO algorithm is proposed. • Four new and simpler conjugation parameters are provided for the conjugate SMO algorithm. • Reduces the number of iterations of SMO and conjugate SMO algorithms and shortens the training time of the SVM model. Support vector machine (SVM) is an important class of methods in pattern recognition, and the sequential minimal optimization (SMO) algorithm is one of the most popular methods for training SVM at present. Based on the conjugate sequential minimal optimization algorithm (CSMO), we propose a novel three-term conjugate-like sequential minimal optimization algorithm (TCSMO) for classification and regression tasks. Compared with the CSMO, although the three-term conjugate-like SMO slightly increases the amount of arithmetic operations in each iteration, it significantly reduces the number of iterations required to converge to the specified accuracy and shortens the training time of the SVM. Additionally, we give a convergence proof of the three-term conjugate-like SMO algorithm and four new conjugate parameters. Numerical experiments show that the three-term conjugate-like SMO algorithm performs better numerically in both classification and regression tasks. [ABSTRACT FROM AUTHOR]

Friction modifier (FM) is a newly developed third medium to control the service performance of wheel/rail. The wheel/rail performance is influenced by the wheel/rail contact conditions and FM application parameters. Therefore, the effects of FM application parameter and the wheel/rail contact parameters on the adhesion and damage behaviors of wheel and rail materials should be explored. In this study, the influences of application amount of FM, the wheel/rail contact stress and the creepage on the adhesion and damage behaviors were studied using a twin-disc machine. Results indicated that the increase in contact stress would reduce the wheel/rail minimum adhesion coefficient and effective holding time of FM. The increase in the creepage would increase the adhesion coefficient and reduce the holding time. Under the wheel/rail contact stresses of 800 and 1100 MPa, the application of FM could reduce wheel/rail wear and damage. But under 1500 MPa, FM could cause serious rail surface damages. Moreover, the surface crack propagation process of rail mainly included three stages: initial stage, transition stage and rapid propagation stage. The "oil wedge effect" was the main mechanism for aggravating the surface damages of rail under 1500 MPa. • Wheel/rail adhesion coefficient is reduced with the increase in FM application amount and contact stress, and the decrease in creep rate. • The minimum adhesion coefficient has a negative relationship with the holding time. • Under 800 and 1100 MPa, the application of FM could alleviate the wheel and rail wear and damages. • Under 1500 MPa, FM will cause serious surface damages to the rail with initial cracks. [ABSTRACT FROM AUTHOR]

In the boron dilution process, the volume control tank in the Chemical and Volume Control System of nuclear power plants has a retention effect on the demineralized water which is injected into the tank as a horizontal positively buoyant jet. The fluid retention hinders the boron concentration in the reactor coolant system from reaching the target value, eventually destabilizing the reactor power. Minimizing retention is consequently essential. However, there are few studies on fluid retention. The current study focuses on studying the fluid retention in the tank with a horizontal positively buoyant jet. An experimentally validated numerical model was used to simulate the flow and mixing inside the tank. A retention coefficient was introduced to compare fluid retention quantitatively. The effects of the operating conditions and tank configuration (inlet flow rate, concentration difference, and nozzle diameter) on fluid retention were studied in the non-stratified and stratified patterns. The results show that the effect of these parameters on fluid retention is negligible in the non-stratified pattern. However, in the stratified pattern, the increase of the inlet flow rate or the decrease of the concentration difference/nozzle diameter leads to the shorter delay stage and weaker fluid retention in the decline stage. Furthermore, the effect of the stratification Richardson number ( R i S F ) on the fluid retention of the tank with fixed geometric parameters is analyzed. The retention coefficient at the characteristic time always increases as the R i S F increases. Meanwhile, the coefficient increases very slowly in the non-stratified pattern. In the stratified pattern, it rises rapidly first and then slowly. Thus, a smaller R i S F is not necessary to reduce fluid retention when the mixing pattern is already the non-stratified pattern in practice. A criterion for pattern transition between stratified and non-stratified is proposed for practical purposes. • The fluid retention of the horizontal positively buoyant jet tank is analyzed. • Effects of operating conditions and tank configuration on the retention are studied. • Fluid retention is intensified as the stratification Richardson number increases. • A criterion is proposed to determine the mixing pattern for practical purposes. [ABSTRACT FROM AUTHOR]

Recent studies suggest that microRNA (miRNA) plays important roles in the control of immune response and tolerance. We previously found that the expression level of antimicrobial peptide gene Drosomycin ( Drs ) is decreased in miR-964 overexpressing flies. Here, we further verified that miR-964 deficiency leads to hyper-activation of Drs . In addition, we employed three widely-used bioinformatic algorithms to screen potential miR-964 targets. Finally, we identified that miR-964 modulates Toll signaling pathway, at least in part, by repressing the expression of Drs . Taken together, our study identifies miR-964 as a modulator of Toll signaling and enriches the repertoire of immune-modulating miRNAs in Drosophila . [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) are endogenous small non-coding RNAs that participate in diverse biological processes via regulating expressions of target genes at post-transcriptional level. Amphioxus, as modern survivor of an ancient chordate lineage, is a model organism for comparative genomics study. However, miRNAs involved in regulating immune responses in Branchiostoma belcheri are largely unclear. Here, we systematically investigated the microRNAs (miRNAs) involved in regulating immune responses in the cephalochordate amphioxus ( Branchiostoma belcheri ) through next-generation deep sequencing of amphioxus samples infected with Vibrio parahemolyticus . We identified 198 novel amphioxus miRNAs, consisting of 12 conserved miRNAs, 33 candidate star miRNAs and 153 potential amphioxus-specific-miRNAs. Using microarray profiling, 14 miRNAs were differentially expressed post infection, suggesting they are immune-related miRNAs. Eight miRNAs ( bbe-miR-92a-3p , bbe-miR-92c-3p , bbe-miR-210-5p, bbe-miR-22-3p , bbe-miR-1∼bbe-miR-133 and bbe-miR-217∼bbe-miR-216 clusters) were significantly increased at 12 h post-infection, while bbe-miR-2072-5p was downregulated at 6 h and 12 h. Three miRNAs, bbe-miR-1-3p , bbe-miR-22-3p and bbe-miR-92a-3p , were confirmed to be involved in immune responses to infection by qRT-PCR. Our findings further clarify important regulatory roles of miRNAs in the innate immune response to bacterial infection in amphioxus. [ABSTRACT FROM AUTHOR]

• A novel posture mapping method is proposed in to avoid the incorrect mapping. • The kinematics solution for SRS 7-DOF robot with posture constraints is derived. • The structure transformation method is modified to reduce the loss of workspace. • An explicit posture mapping and teleoperation framework is proposed. In most industrial robot applications, on-site robot operation is required. However, this is not feasible for certain harsh operating conditions, such as high temperatures and intense radiation. In such instances, teleoperation based on machine vision can be applied, and adding posture constraints helps control the robot to complete more complex tasks. The general idea is to use quadratic programming or other optimization methods to solve the problem. In order to improve accuracy and ensure real-time performance, a real-time explicit mapping and teleoperation control (REMTC) is proposed. Based on the principle of "included angle minimization" (IAM), the incorrect mapping problem which might be caused by the traditional method is solved. In addition, considering that the analytical inverse solution algorithm is not as universal as the general optimization framework, an improved structure transformation method is proposed, so that the algorithm can be applied to both Spherical- Revolute-Spherical (SRS) and non-SRS robots. Finally, the experiment verifies the effectiveness of the algorithm in real-time performance, accuracy and reliability. [ABSTRACT FROM AUTHOR]

Drosophila have served as a model for research on innate immunity for decades. However, knowledge of the post-transcriptional regulation of immune gene expression by microRNAs (miRNAs) remains rudimentary. In the present study, using small RNA-seq and bioinformatics analysis, we identified 67 differentially expressed miRNAs in Drosophila infected with Escherichia coli compared to injured flies at three time-points. Furthermore, we found that 21 of these miRNAs were potentially involved in the regulation of Imd pathway-related genes. Strikingly, based on UAS-miRNAs line screening and Dual-luciferase assay, we identified that miR-9a and miR-981 could both negatively regulate Drosophila antibacterial defenses and decrease the level of the antibacterial peptide, Diptericin. Taken together, these data support the involvement of miRNAs in the regulation of the Drosophila Imd pathway. [ABSTRACT FROM AUTHOR]

Although innate immunity mediated by Toll signaling has been extensively studied in Drosophila melanogaster , the role of miRNAs in regulating the Toll-mediated immune response remains largely unknown. In this study, following Gram-positive bacterial challenge, we identified 93 differentially expressed miRNAs via genome-wide miRNA screening. These miRNAs were regarded as immune response related (IRR). Eight miRNAs were confirmed to be involved in the Toll-mediated immune response upon Gram-positive bacterial infection through genetic screening of 41 UAS-miRNA lines covering 60 miRNAs of the 93 IRR miRNAs. Interestingly, four out of these eight miRNAs, miR-310, miR-311, miR-312 and miR-313, are clustered miRNAs and belong to the miR-310 family. These miR-310 family members were shown to target and regulate the expression of Drosomycin, an antimicrobial peptide produced by Toll signaling. Taken together, our study implies important regulatory roles of miRNAs in the Toll-mediated innate immune response of Drosophila upon Gram-positive bacterial infection. [ABSTRACT FROM AUTHOR]

Dioxins are stable, ubiquitous, persistent, and halogenated environmental pollutants that have recently garnered increasing attention. This study constructed a microcosmic system to simulate the real breeding conditions of the Chinese mitten crab (Eriocheir sinensis) to evaluate the impact of environmental dioxins on these aquaculture animals. Histological observation and detection of antioxidant enzyme activities revealed that dioxin exposure for different durations substantially damaged the hepatopancreas of Chinese mitten crabs, increasing the enzymatic activities of total superoxide dismutase (T-SOD) and catalase (CAT) but decreasing that of malondialdehyde (MDA). We also obtained the gene expression profiles of the hepatopancreas corresponding to different periods of dioxin exposure using RNA-seq technology. Compared with the control group, 2999 and 941 differentially expressed genes (DEGs) corresponding to different periods of dioxin exposure were identified in the hepatopancreas. Enrichment analysis indicated that some pathways, such as those governing carbohydrate metabolism, fatty acid metabolism, and immune disease, also responded to dioxin exposure. Subsequently, we selectively analyzed DEGs involved in oxidoreductase activity, carbohydrate metabolic processes, and other processes, identifying that increased expression of Hsp70 , Ldh , and Trx1 and decreased expression of Lgbp , Bgal1 , and Acsbg2 were potentially caused by sensitivity to environmental dioxin exposure. Therefore, we contend that, although crabs exposed to unfavorable environmental pollutants, such as dioxin, may adapt via antioxidant and immune response modulation. However, continued dioxin exposure would disrupt such homeostatic restorative capabilities. Thus, this study may provide new insights into the toxicological effects exerted by dioxin on aquatic organisms, such as E. sinensis, as well as the mechanisms underlying such toxicity. • Dioxin exposure for different durations substantially damaged the hepatopancreas of E. sinensis. • The abnormal expression of Hsp70 , Ldh , Trx , Lgbp , Bgal1 and Acsbg2 significantly correlated with long-term dioxin exposure. • E. sinensis might adapt to long-term dioxin-exposed by regulating antioxidant and immune responses. [ABSTRACT FROM AUTHOR]

• A link between substrates, performance, isotopes and functional microbes was built. • δ18O was another indicator to discern carbon sources in addition to site preference. • Glucose led to the least N 2 O production due to the lowest abundance of NorB. • Glucose produced N 2 O with the highest site preference due to Thiobacillus -type cNorB. • Cellobiose led to the lowest δ18O due to cNorB and qNorB carried by Alicycliphilus. Denitrification is one of the major sources of N 2 O in freshwaters. Diverse forms of organic compounds act as the electron donors for microbial denitrification. However, the influences of carbon sources on N 2 O production, N 2 O reduction, isotope fractionation and functional microbes during denitrification were largely unknown. In this study, five forms of carbon sources (i.e. acetate, citrate, glucose, cellobiose and leucine) were used to enrich denitrifiers in freshwater sediments. N 2 O conversion in the enrichments was investigated by a combination of inhibition technique, natural stable isotope method and metagenomics. Acetylene was effective in inhibiting N 2 O reduction without influencing the isotopic characteristics during N 2 O production. Glucose led to the least N 2 O production and reduction, in accordance with the lowest abundance of both NO and N 2 O reductases in this enrichment. δ18O and site preference value (SP, =δ15Nα-δ15Nβ) of N 2 O were sensitive to discriminate the five carbon sources, except when comparing acetate and leucine. Isotopic values of N 2 O were not significantly different in these two enrichments due to the similarity of NO reductases - Pseudomonas -type cNorB. Specifically, the enrichment with cellobiose produced N 2 O with the lowest δ18O values (39.4‰±1.1‰), due to Alicycliphilus with both cNorB and qNorB. The enrichment with glucose led to the highest SP values (8.9‰±8.6‰), caused by Thiobacillus -type cNorB. Our results demonstrated the link between carbon sources, N 2 O production and reduction, isotopic signatures, microbial populations and enzymes during denitrification in freshwaters. [Display omitted] [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of oxygen concentrations in modified atmosphere packaging (MAP) on pork color and protein oxidation under refrigerated storage. Pork steaks were vacuum packaged or MAP packed with different levels of oxygen (40%, 60% and 80%), and stored for 14 days at 4 °C. After storage, the instrumental color, purge loss, cooking loss and shear fore were measured, and levels of protein oxidation in both the sarcoplasmic and myofibrillar proteins were quantified separately by the determination of carbonyl contents, thiol contents, loss of specific amino acid residues, and formation of α-aminoadipic semialdehyde. Results suggested that 40% of oxygen in MAP was sufficient to obtain highest redness, and higher oxygen levels showed little improvement but led to further protein carbonylation and meat toughening. Meanwhile, the sarcoplasmic proteins seemed to be more vulnerable to protein oxidation than the myofibrillar proteins. In particular, the formation of α-aminoadipic semialdehyde might contribute little to the carbonylation of both protein fractions, and possible reasons were discussed. [ABSTRACT FROM AUTHOR]

Cerebral aneurysm (CA) rupture is a major cause of subarachnoid hemorrhage with high morbidity and mortality. Using an animal model, we examined the potential of endothelial colony-forming cells (ECFCs) transfusion on vascular degeneration after CA induction and underlying mechanisms. CA was induced in the right anterior cerebral artery–olfactory artery (ACA/OA) bifurcations in Sprague–Dawley rats with or without ECFCs transfusion. The degeneration of internal elastic lamina (IEL), media thickness and CA size were evaluated. Expression of matrix metalloproteinase-2 and 9 (MMP-2 and 9), tissue inhibitor of metalloproteinase-1 (TIMP-1), macrophage chemoattractant protein-1 (MCP-1), vascular cell adhesion molecule-1 (VCAM-1), nuclear factor κB (NF-κB), endothelial nitric oxide synthase (eNOS), B-cell leukemia/lymphoma-2 (Bcl-2), and inducible nitric oxide synthase (iNOS) were analyzed by quantitative real-time polymerase chain reaction. The macrophages infiltration and apoptosis of smooth muscle cells (SMCs) were examined immunohistologically. Rats in CA+ECFCs transfusion group showed a notable reduction in IEL degeneration, media thinning and CA size compared with those in CA+saline group. ECFCs transfusion inhibited the MMP-driven wall destruction by downregulating MMP-2, MMP-9 expression and upregulating TIMP-1. ECFCs transfusion dramatically decreased VCAM-1 and NF-κB expression, increased eNOS expression and caused no change in MCP-1 expression, which was accompanied by reduced macrophages infiltration. Moreover, ECFCs transfusion reversed downregulation of Bcl-2 expression and upregulation of iNOS expression, and decreased SMCs apoptosis. Collectively, these findings suggest that ECFCs transfusion confers protection against degeneration of aneurysmal wall by inhibiting inflammatory cascades and SMCs apoptosis. [ABSTRACT FROM AUTHOR]

Microbial denitrification is a main source of nitrous oxide (N 2 O) emissions which have strong greenhouse effect and destroy stratospheric ozone. Though the importance of sulfide driven chemoautotrophic denitrification has been recognized, its contribution to N 2 O emissions in nature remains elusive. We built up long-term sulfide-added microcosms with sediments from two freshwater lakes. Chemistry analysis confirmed sulfide could drive nitrate respiration in long term. N 2 O accumulated to over 1.5% of nitrate load in both microcosms after long-term sulfide addition, which was up to 12.9 times higher than N 2 O accumulation without sulfide addition. Metagenomes were extracted and sequenced during microcosm incubations. 16 S rRNA genes of Thiobacillus and Defluviimonas were gradually enriched. The nitric oxide reductase with c-type cytochromes as electron donors (cNorB) increased in abundance, while the nitric oxide reductase receiving electrons from quinols (qNorB) decreased in abundance. cnorB genes similar to Thiobacillus were enriched in both microcosms. In parallel, enrichment was observed for enzymes involved in sulfur oxidation, which supplied electrons to nitrate respiration, and enzymes involved in Calvin Cycle, which sustained autotrophic cell growth, implying the coupling relationship between carbon, nitrogen and sulfur cycling processes. Our results suggested sulfur pollution considerably increased N 2 O emissions in natural environments. • N2O accumulation was up to 12.9 times higher after long-term sulfide input. • N2O production was associated more with c-type cytochrome nitric oxide reductases. • cnorB genes similar to Thiobacillus were enriched in both microcosms. • Sulfur oxidation supplied electrons to nitrate respiration. • Microbes sustained autotrophic growth through the Calvin cycle. [ABSTRACT FROM AUTHOR]