Genome-centric metagenomes unveiling the hidden resistome in an anchialine cave.

BACKGROUND: Antibiotic resistance is a critical global concern, posing significant challenges to human health and medical treatments. Studying antibiotic resistance genes (ARGs) is essential not only in clinical settings but also in diverse environmental contexts. However, ARGs in unique environments such as anchialine caves, which connect both fresh and marine water, remain largely unexplored despite their intriguing ecological characteristics. RESULTS: We present the first study that comprehensively explores the occurrence and distribution of ARGs and mobile genetic elements (MGEs) within an anchialine cave. Utilizing metagenomic sequencing we uncovered a wide array of ARGs with the bacitracin resistance gene, bacA and multidrug resistance genes, being the most dominant. The cave's microbial community and associated resistome were significantly influenced by the salinity gradient. The discovery of novel ß-lactamase variants revealed the cave's potential as a reservoir for previously undetected resistance genes. ARGs in the cave demonstrated horizontal transfer potential via plasmids, unveiling ecological implications. CONCLUSIONS: These findings highlight the need for further exploration of the resistome in unique environments like anchialine caves. The interconnected dynamics of ARGs and MGEs within anchialine caves offer valuable insights into potential reservoirs and mechanisms of antibiotic resistance in natural ecosystems. This study not only advances our fundamental understanding but also highlights the need for a comprehensive approach to address antibiotic resistance in diverse ecological settings.

Carbohydrate response element-binding protein (ChREBP) mediates decreased SNAP25 expression in islets from diabetic Goto-Kakizaki (GK) rats.

SNAP25 plays an essential role in the glucose-stimulated insulin secretion (GSIS) of pancreatic ß-cells. Carbohydrate response element-binding protein (ChREBP) is an important transcription factor in ß-cells and, in this study, we aimed to explore whether ChREBP regulates SNAP25 expression in ß-cells. We show that diabetic Goto-Kakizaki (GK) rats exhibited impaired insulin secretion and hyperglycemia, along with decreased SNAP25 expression and ChREBP phosphorylation in islets. SNAP25 knockdown decreased GSIS in ß-cells, while SNAP25 overexpression increased GSIS in ß-cells. Activation or overexpression of ChREBP led to reduced SNAP25 expression and subsequent suppression of GSIS. Conversely, ChREBP knockdown mitigated the reduction in SNAP25 expression caused by high glucose. Mechanistically, the activation of ChREBP by high glucose increased its occupancy and decreased the level of H3K4me3 at the Snap25 promoter. Our findings reveal the novel regulatory mechanisms of SNAP25 expression in ß-cells and suggest that SNAP25 may be involved in the regulation of ß-cell secretory function controlled by ChREBP.

Unnoticed antimicrobial resistance risk in Tibetan cities unveiled by sewage metagenomic surveillance: Compared to the eastern Chinese cities.

Sewage surveillance is a cost-effective tool for assessing antimicrobial resistance (AMR) in urban populations. However, research on sewage AMR in remote areas is still limited. Here, we used shotgun metagenomic sequencing to profile antibiotic resistance genes (ARGs) and ARG-carrying pathogens (APs) across 15 cities in Tibetan Plateau (TP) and the major cities in eastern China. Notable regional disparities in sewage ARG composition were found, with a significantly higher ARG abundance in TP (2.97 copies/cell). A total of 542 and 545 APs were identified in sewage from TP and the East, respectively, while more than 40 % carried mobile genetic elements (MGEs). Moreover, 65 MGEs-carrying APs were identified as World Health Organization (WHO) priority-like bacterial and fungal pathogens. Notably, a fungal zoonotic pathogen, Enterocytozoon bieneusi, was found for the first time to carry a nitroimidazole resistance gene (nimJ). Although distinct in AP compositions, the relative abundances of APs were comparable in these two regions. Furthermore, sewage in TP was found to be comparable to the cities in eastern China in terms of ARG mobility and AMR risks. These findings provide insights into ARGs and APs distribution in Chinese sewage and stress the importance of AMR surveillance and management strategies in remote regions.

Distinct influences of altitude on microbiome and antibiotic resistome assembly in a glacial river ecosystem of Mount Everest.

The profound influences of altitude on aquatic microbiome were well documented. However, differences in the responses of different life domains (bacteria, microeukaryotes, viruses) and antibiotics resistance genes (ARGs) in glacier river ecosystems to altitude remain unknown. Here, we employed shotgun metagenomic and amplicon sequencing to characterize the altitudinal variations of microbiome and ARGs in the Rongbu River, Mount Everest. Our results indicated the relative influences of stochastic processes on microbiome and ARGs assembly in water and sediment were in the following order: microeukaryotes < ARGs < viruses < bacteria. Moreover, distinct assembly patterns of the microbiome and ARGs were found in response to differences in altitude, the latter of which shift from deterministic to stochastic processes with increasing differences in altitude. Partial least squares path modeling revealed that mobile genetic elements (MGEs) and viral ß-diversity were the major factors influencing the ARG abundances. Taken together, our work revealed that altitude-caused environmental changes led to significant changes in the composition and assembly processes of the microbiome and ARGs, while ARGs had a unique response pattern to altitude. Our findings provide novel insights into the impacts of altitude on the biogeographic distribution of microbiome and ARGs, and the associated driving forces in glacier river ecosystems.

Temperature-driven shifts in bacterioplankton biodiversity: Implications for cold-preferred species in warming Tibetan proglacial lakes.

Recent climate warming and associated glacier retreat have dramatically changed the environmental conditions and microbial inhabitants of proglacial lakes. However, our understanding of the effects of climate warming and glacial influence on microbial biodiversity in these lakes remain relatively limited. Here, we studied bacterioplankton communities in 22 proglacial lakes on the Tibetan Plateau, spanning a range of nearly 7 °C in mean annual temperature (MAT), and examined the effects of climate and glaciers on their biodiversity by a space-to-time substitution. MAT emerged as the primary environmental driver of bacterioplankton biodiversity compared to glacial influence, increasing species richness and decreasing ß-diversity. We identified 576 low-MAT (cold-preferred) species and 2,088 high-MAT (warm-preferred) species, and found that low-MAT species are less environmentally adapted, with their numbers declining as temperature increased. These results advance our understanding of temperature-driven bacterioplankton dynamics by disentangling the contrasting responses and adaptations of cold-preferred and warm-preferred species. Our findings highlight the vulnerability of cold-specialist taxa and the potential biodiversity losses associated with climate warming in the rapidly changing proglacial lakes.

Are workers also vulnerable to the impact of ambient air pollution? Insight from a large-scale ventilatory exam.

It remains unclear how ambient air pollution may affect the prevalence of obstructive ventilatory dysfunction (OVD) among workers. We aim to assess the association of a comprehensive set of ambient air pollutants with OVD prevalence in workers and to explore the potential interactive effects of the occupational factors. This is a population-based cross-sectional study among 305,022 participants from the Guangdong Province, China. Mixed-effects models were used to obtain differences in the OVD risk associated with a 10 µg/m3 increase in ambient air pollution. We found that for each 10 µg/m3 increase in PM2.5, PM10, PM coarse, O3, and NO2 concentrations, the odds ratio (OR) for OVD in workers is 1.324 (95 % confidence interval (CI), 1.282-1.367), 1.292 (95 % CI, 1.268-1.315),1.666 (95 % CI, 1.614-1.719), 1.153 (95 % CI, 1.142-1.165), and 1.023 (95 % CI, 1.012-1.033). We observed that young participants (18-38 years old), women, participants with longer years of service (>48 months), participants working in large enterprises, professional skills workers, and production and manufacturing workers have higher estimated effects. In addition, we also found that workers exposed to high temperatures have higher estimated effects under air pollutants exposure, while workers exposed to noise have higher estimated effects under PM2.5, PM10, NO2, and O3 exposure. Workers exposed to dust have a lower risk of developing OVD under exposure to ambient air pollutants compared to those not exposed. Our results indicate that ambient air pollution increases the risk of OVD in workers. Moreover, air pollutants exhibit a greater estimated effect among workers exposed to high temperatures or noise. Our research findings highlight the importance of fully considering the impact of ambient air pollution on protecting the respiratory health of workers.

Reduction in antimicrobial resistance in a watershed after closure of livestock farms.

Natural environments play a crucial role in transmission of antimicrobial resistance (AMR). Development of methods to manage antibiotic resistance genes (ARGs) in natural environments are usually limited to the laboratory or field scale, partially due to the complex dynamics of transmission between different environmental compartments. Here, we conducted a nine-year longitudinal profiling of ARGs at a watershed scale, and provide evidence that restrictions on livestock farms near water bodies significantly reduced riverine ARG abundance. Substantial reductions were revealed in the relative abundance of genes conferring resistance to aminoglycosides (42%), MLSB (36%), multidrug (55%), tetracyclines (53%), and other gene categories (59%). Additionally, improvements in water quality were observed, with distinct changes in concentrations of dissolved reactive phosphorus, ammonium, nitrite, pH, and dissolved oxygen. Antibiotic residues and other pharmaceuticals and personal care products (PPCPs) maintain at a similarly low level. Microbial source tracking demonstrates a significant decrease in swine fecal indicators, while human fecal pollution remains unchanged. These results suggest that the reduction in ARGs was due to a substantial reduction in input of antibiotic resistant bacteria and genes from animal excreta. Our findings highlight the watershed as a living laboratory for understanding the dynamics of AMR, and for evaluating the efficacy of environmental regulations, with implications for reducing environmental risks associated with AMR on a global scale.

A Facile Strategy for Constructing High-Performance Polymer Electrolytes via Anion Modification and Click Chemistry for Rechargeable Magnesium Batteries.

Polymer electrolytes play a crucial role in advancing rechargeable magnesium batteries (RMBs) owing to their exceptional characteristics, including high flexibility, superior interface compatibility, broad electrochemical stability window, and enhanced safety features. Despite these advantages, research in this domain remains nascent, plagued by single preparation approaches and challenges associated with the compatibility between polymer electrolytes and Mg metal anode. In this study, we present a novel synthesis strategy to fabricate a glycerol α,α'-diallyl ether-3,6-dioxa-1,8-octanedithiol-based composite gel polymer electrolyte supported by glass fiber substrate (GDT@GF CGPE) through anion modification and thiol-ene click chemistry polymerization. The developed route exhibits novelty and high efficiency, leading to the production of GDT@GF CGPEs featuring exceptional mechanical properties, heightened ionic conductivity, elevated Mg2+ transference number, and commendable compatibility with Mg anode. The assembled modified Mo6S8||GDT@GF||Mg cells exhibit outstanding performance across a wide temperature range and address critical safety concerns, showcasing the potential for applications under extreme conditions. Our innovative preparation strategy offers a promising avenue for the advancement of polymer electrolytes in high-performance rechargeable magnesium batteries, while also opens up possibilities for future large-scale applications and the development of flexible electronic devices.

Commercial reverse osmosis point-of-use systems in Egypt failed to purify tap water.

This study addresses the heightened global reliance on point-of-use (PoU) systems driven by water quality concerns, ageing infrastructure, and urbanization. While widely used in Egypt, there is a lack of comprehensive evaluation of these systems. We assessed 10 reverse osmosis point-of-use systems, examining physicochemical, bacteriological, and protozoological aspects of tap water (inlets) and filtered water (outlets), adhering to standard methods for the examination of water and wastewater. Results showed significant reductions in total dissolved solids across most systems, with a decrease from 210 ± 23.6 mg/L in tap water to 21 ± 2.8 mg/L in filtered water for PoU-10. Ammonia nitrogen levels in tap water decreased from 0.05 ± 0.04 to 2.28 ± 1.47 mg/L to 0.02 ± 0.04 to 0.69 ± 0.64 mg/L in filtered water. Despite this, bacterial indicators showed no significant changes, with some systems even increasing coliform levels. Protozoological analysis identified prevalent Acanthamoeba (42.5%), less frequent Naegleria (2.5%), Vermamoeba vermiformis (5%), and potentially pathogenic Acanthamoeba genotypes. Elevated bacterial indicators in filtered water of point-of-use systems, combined with essential mineral removal, indicate non-compliance with water quality standards, posing a public health concern. Further research on the long-term health implications of these filtration systems is essential.

Ecological and evolutionary processes involved in shaping microbial habitat generalists and specialists in urban park ecosystems.

Microbiomes are integral to ecological health and human well-being; however, their ecological and evolutionary drivers have not been systematically investigated, especially in urban park ecosystems. As microbes have different levels of tolerance to environmental changes and habitat preferences, they can be categorized into habitat generalists and specialists. Here, we explored the ecological and evolutionary characteristics of both prokaryotic and microeukaryotic habitat generalists and specialists from six urban parks across five habitat types, including moss, soil, tree hole, water, and sediment. Our results revealed that different ecological and evolutionary processes maintained and regulated microbial diversity in urban park ecosystems. Under ecological perspective, community assembly of microbial communities was mainly driven by stochastic processes; however, deterministic processes were higher for habitat specialists than generalists. Microbial interactions were highly dynamic among habitats, and habitat specialists played key roles as module hubs in intradomain networks. In aquatic interdomain networks, microeukaryotic habitat specialists and prokaryotic habitat specialists played crucial roles as module hubs and connectors, respectively. Furthermore, analyzing evolutionary characteristics, our results revealed that habitat specialists had a much higher diversification potential than generalists, while generalists showed shorter phylogenetic branch lengths as well as larger genomes than specialists. This study broadens our understanding of the ecological and evolutionary features of microbial habitat generalists and specialists in urban park ecosystems across multi-habitat. IMPORTANCE: Urban parks, as an important urban greenspace, play essential roles in ecosystem services and are important hotspots for microbes. Microbial diversity is driven by different ecological and evolutionary processes, while little is currently known about the distinct roles of ecological and evolutionary features in shaping microbial diversity in urban park ecosystems. We explored the ecological and evolutionary characteristics of prokaryotic and microeukaryotic habitat generalists and specialists in urban park ecosystems based on a representative set of different habitats. We found that different ecological and evolutionary drivers jointly maintained and regulated microbial diversity in urban park microbiomes through analyzing the community assembly process, ecological roles in hierarchical interaction, and species diversification potential. These findings significantly advance our understanding regarding the mechanisms governing microbial diversity in urban park ecosystems.

A hybrid system for Nickel ions removal from synthesized wastewater using adsorption assisted with electrocoagulation.

The presence of heavy metal ions in water environments has raised significant concerns, necessitating practical solutions for their complete removal. In this study, a combination of adsorption and electrocoagulation (ADS + EC) techniques was introduced as an efficient approach for removing high concentrations of nickel ions (Ni2+) from aqueous solutions, employing low-cost sunflower seed shell biochar (SSSB). The combined techniques demonstrated superior removal efficiency compared to individual methods. The synthesized SSSB was characterized using SEM, FT-IR, XRD, N2-adsorption-desorption isotherms, XPS, and TEM. Batch processes were optimized by investigating pH, adsorbent dosage, initial nickel concentration, electrode effects, and current density. An aluminum (Al) electrode electrocoagulated particles and removed residual Ni2+ after adsorption. Kinetic and isotherm models examined Ni2+ adsorption and electrocoagulation coupling with SSSB-based adsorbent. The results indicated that the kinetic data fit well with a pseudo-second-order model, while the experimental equilibrium adsorption data conformed to a Langmuir isotherm under optimized conditions. The maximum adsorption capacity of the activated sunflower seed shell was determined to be 44.247 mg.g-1. The highest nickel ion removal efficiency of 99.98% was observed at initial pH values of 6.0 for ADS and 4.0 for ADS/EC; initial Ni2+ concentrations of 30.0 mg/L and 1.5 g/L of SSSB; initial current densities of 0.59 mA/cm2 and 1.32 kWh/m3 were also found to be optimal. The mechanisms involved in the removal of Ni2+ from wastewater were also examined in this research. These findings suggest that the adsorption-assisted electrocoagulation technique has a remarkable capacity for the cost-effective removal of heavy metals from various wastewater sources.

Fate of contaminants of emerging concern in two wastewater treatment plants after retrofitting tertiary treatment for reduction of nitrogen discharge.

More and more previously designed wastewater treatment plants (WWTPs) are upgraded to tertiary treatment to meet the higher effluent discharge standards of conventional pollutants. Contaminants of emerging concern (CECs) can cause adverse effects on organisms and usually flow into WWTPs along with urban sewage. How the retrofitted WWTPs targeting conventional pollutants will influence the treatment efficiency of CECs is seldom discussed. This study investigates the removal of CECs in two full-scale newly retrofitted WWTPs (CD and JM WWTPs), containing high-efficiency sedimentation tank and denitrification deep bed filter for enhancing total nitrogen removal. The overall CEC removal efficiencies in the CD and JM WWTPs were 73.79 % and 93.63 %, respectively. Mass balance results indicated that CD WWTP and JM WWTP release a total of 36.89 and 88.58 g/d of CECs into the environment through effluent and excess sludge, respectively. Analysis of the concentration of CECs along the treatment process revealed most CECs were removed in the biological treatment units. The incorporation of newly constructed tertiary treatment proved beneficial for CEC removal and removed 2.93 % and 2.36 % CECs, corresponding to CEC removal of 2.92 and 27.49 g/d in the CD and JM WWTPs, respectively. The data of this study were further used to evaluate the suitability of the SimpleTreat model for simulating the fate of CECs in WWTPs. The predicted fraction of CECs discharged through the biological treatment effluent were generally within ten-fold difference from the measured results, highlighting its potential for estimating CEC removal in WWTPs.

GLP-1 signaling-regulated SNAP25 is involved in improved insulin secretion in diabetic GK rats after Roux-en-Y gastric bypass surgery.

BACKGROUND: Roux-en-Y gastric bypass surgery (RYGB) improves glucose-stimulated insulin secretion (GSIS) in type 2 diabetes (T2D) patients. SNAP25 plays an essential role in GSIS. Clinical studies indicate that enhanced GLP-1 signaling is an important contributor to the improved ß-cell function in T2D. We aimed to explore whether GLP-1-regulated SNAP25 is involved in the enhanced secretory function of ß-cells in diabetic Goto-Kakizaki (GK) rats after RYGB. METHODS AND RESULTS: RYGB or sham surgery was conducted in GK rats. mRNA and protein expression of SNAP25 was assessed by qPCR and Western blot, respectively. Occupancy of CREB and acetyltransferase CBP and acetylation of histone H3 (ACH3) at the Snap25 promoter were determined using ChIP assay. RYGB led to increased SNAP25 expression and CREB phosphorylation in islets from GK rats. Increased SNAP25 improved GSIS in ß-cells cultured in high glucose conditions. Consistent with increased plasma GLP-1 after RYGB, GLP-1R agonist exendin4 increased SNAP25 expression and CREB phosphorylation in ß-cells. Mechanistically, exendin4 promoted the recruitment of CREB and CBP, thereby increasing ACH3 at the Snap25 promoter. Consistently, inhibition of CBP attenuated the effect of exendin4 on SNAP25 expression. Furthermore, the knockdown of SNAP25 diminished the increase of GSIS potentiated by chronic GLP-1 culture in INS-1 832/13 cells. CONCLUSIONS: Our findings unravel the novel mechanisms of RYGB-enhanced SNAP25 expression in ß-cells, and SNAP25 may contribute to the improved ß-cell secretory function induced by RYGB.

Strategies of chemolithoautotrophs adapting to high temperature and extremely acidic conditions in a shallow hydrothermal ecosystem.

BACKGROUND: Active hydrothermal vents create extreme conditions characterized by high temperatures, low pH levels, and elevated concentrations of heavy metals and other trace elements. These conditions support unique ecosystems where chemolithoautotrophs serve as primary producers. The steep temperature and pH gradients from the vent mouth to its periphery provide a wide range of microhabitats for these specialized microorganisms. However, their metabolic functions, adaptations in response to these gradients, and coping mechanisms under extreme conditions remain areas of limited knowledge. In this study, we conducted temperature gradient incubations of hydrothermal fluids from moderate (pH = 5.6) and extremely (pH = 2.2) acidic vents. Combining the DNA-stable isotope probing technique and subsequent metagenomics, we identified active chemolithoautotrophs under different temperature and pH conditions and analyzed their specific metabolic mechanisms. RESULTS: We found that the carbon fixation activities of Nautiliales in vent fluids were significantly increased from 45 to 65 °C under moderately acidic condition, while their heat tolerance was reduced under extremely acidic conditions. In contrast, Campylobacterales actively fixed carbon under both moderately and extremely acidic conditions under 30 - 45 °C. Compared to Campylobacterales, Nautiliales were found to lack the Sox sulfur oxidation system and instead use NAD(H)-linked glutamate dehydrogenase to boost the reverse tricarboxylic acid (rTCA) cycle. Additionally, they exhibit a high genetic potential for high activity of cytochrome bd ubiquinol oxidase in oxygen respiration and hydrogen oxidation at high temperatures. In terms of high-temperature adaption, the rgy gene plays a critical role in Nautiliales by maintaining DNA stability at high temperature. Genes encoding proteins involved in proton export, including the membrane arm subunits of proton-pumping NADH: ubiquinone oxidoreductase, K+ accumulation, selective transport of charged molecules, permease regulation, and formation of the permeability barrier of bacterial outer membranes, play essential roles in enabling Campylobacterales to adapt to extremely acidic conditions. CONCLUSIONS: Our study provides in-depth insights into how high temperature and low pH impact the metabolic processes of energy and main elements in chemolithoautotrophs living in hydrothermal ecosystems, as well as the mechanisms they use to adapt to the extreme hydrothermal conditions. Video Abstract.

Gut microbiota related response of Oryzias melastigma to combined exposure of polystyrene microplastics and tetracycline.

The co-existence of microplastics (MPs) and antibiotics in the coastal environment poses a combined ecological risk. Single toxic effects of MPs or antibiotics on aquatic organisms have been verified, however, the exploration of their combined toxic effects remains limited. Here, foodborne polystyrene microplastics (PS-MPs, 10 µm, 0.1 % w/w in food) and waterborne tetracyclines (TC, 50 µg/L) were used to expose an estuarine fish Oryzias melastigma for four weeks. We found that the aqueous availability of TC was not significantly altered coexisting with MPs. The fish body weight gain was significantly slower in TC alone or combined groups than the control group, consistent with the lower lipid content in livers. The body length gain was significantly inhibited by the combined presence compared to the single exposure. Both exposures led to a shift of gut microbiota composition and diversity. TC and the combined group possessed similar gut microbiota which is distinct from PS-MPs and the control group. The Firmicutes/Bacteroidetes (F/B) ratio in the TC and combined groups were significantly lower compared to the control, while the PS-MPs group showed no significant impact. Metabolomic analysis of the fish liver confirmed the shift of metabolites in specific pathways after different exposures. More, a number of gut microbiota-related metabolites on lipid metabolism was perturbed, which were annotated in arachidonic acid metabolism and linoleic acid metabolism. In all, TC modulates bacterial composition in the fish gut and disturbs their liver metabolites via the gut-liver axis, which led to the slower growth of O. melastigma. More, the adverse impact was aggravated by the co-exposure to foodborne PS-MPs.

PacBio next-generation sequencing uncovers Apicomplexa diversity in different habitats.

The phylum Apicomplexa comprises a large group of intracellular protozoan parasites. These microorganisms are known to infect a variety of vertebrate and invertebrate hosts, leading to significant medical and veterinary conditions such as toxoplasmosis, cryptosporidiosis, theileriosis, and eimeriosis. Despite their importance, comprehensive data on their diversity and distribution, especially in riverine environments, remain scant. To bridge this knowledge gap, we utilized next-generation high-throughput 18S rRNA amplicon sequencing powered by PacBio technology to explore the diversity and composition of the Apicomplexa taxa. Principal component analysis (PCA) and principal coordinate analysis (PCoA) indicated the habitat heterogeneity for the physicochemical parameters and the Apicomplexa community. These results were supported by PERMANOVA (P < 0.001), ANOSIM (P < 0.001), Cluster analysis, and Venn diagram. Dominant genera of Apicomplexa in inlet samples included Gregarina (38.54%), Cryptosporidium (32.29%), and Leidyana (11.90%). In contrast, outlet samples were dominated by Babesia, Cryptosporidium, and Theileria. While surface water samples revealed 16% and 8.33% relative abundance of Toxoplasma and Cryptosporidium, respectively. To our knowledge, the next-generation high throughput sequencing covered a wide range of parasites in Egypt for the first time, which could be useful for legislation of the standards for drinking water and wastewater reuse.

Anti-inflammatory protein TSG-6 secreted by BMSCs attenuates silica-induced acute pulmonary inflammation by inhibiting NLRP3 inflammasome signaling in macrophages.

Silicosis is a severe occupational lung disease caused by inhalation of silica particles. Unfortunately, there are currently limited treatment options available for silicosis. Recent advances have indicated that bone marrow mesenchymal stem cells (BMSCs) have a therapeutic effect on silicosis, but their efficacy and underlying mechanisms remain largely unknown. In this study, we focused on the early phase of silica-induced lung injury to investigate the therapeutic effect of BMSCs. Our findings demonstrated that BMSCs attenuated silica-induced acute pulmonary inflammation by inhibiting NLRP3 inflammasome pathways in lung macrophages. To further understand the mechanisms involved, we utilized RNA sequencing to analyze the transcriptomes of BMSCs co-cultured with silica-stimulated bone marrow-derived macrophages (BMDMs). The results clued tumor necrosis factor-stimulated gene 6 (TSG-6) might be a potentially key paracrine secretion factor released from BMSCs, which exerts a protective effect. Furthermore, the anti-inflammatory and inflammasome pathway inhibition effects of BMSCs were attenuated when TSG-6 expression was silenced, both in vivo and in vitro. Additionally, treatment with exogenous recombinant mouse TSG-6 (rmTSG-6) demonstrated similar effects to BMSCs in attenuating silica-induced inflammation. Overall, our findings suggested that BMSCs can regulate the activation of inflammasome in macrophages by secreting TSG-6, thereby protecting against silica-induced acute pulmonary inflammation both in vivo and in vitro.

Enforcing energy consumption promotes microbial extracellular respiration for xenobiotic bioconversion.

Extracellular electron transfer (EET) empowers electrogens to catalyse the bioconversion of a wide range of xenobiotics in the environment. Synthetic bioengineering has proven effective in promoting EET output. However, conventional strategies mainly focus on modifications of EET-related genes or pathways, which leads to a bottleneck due to the intricate nature of electrogenic metabolic properties and intricate pathway regulation that remain unelucidated. Herein, we propose a novel EET pathway-independent approach, from an energy manipulation perspective, to enhance microbial EET output. The Controlled Hydrolyzation of ATP to Enhance Extracellular Respiration (CHEER) strategy promotes energy utilization and persistently reduces the intracellular ATP level in Shewanella oneidensis, a representative electrogenic microbe. This approach leads to the accelerated consumption of carbon substrate, increased biomass accumulation and an expanded intracellular NADH pool. Both microbial electrolysis cell and microbial fuel cell tests exhibit that the CHEER strain substantially enhances EET capability. Analysis of transcriptome profiles reveals that the CHEER strain considerably bolsters biomass synthesis and metabolic activity. When applied to the bioconversion of model xenobiotics including methyl orange, Cr(VI) and U(VI), the CHEER strain consistently exhibits enhanced removal efficiencies. This work provides a new perspective and a feasible strategy to enhance microbial EET for efficient xenobiotic conversion.

Dissemination of antibiotic resistance genes from the Pearl River Estuary to adjacent coastal areas.

The spread of antibiotic resistance genes (ARGs) is a growing concern over the world's various environments. Coastal environments may receive pollutants from land runoffs via estuaries. However, the impact of ARG contamination from estuarine regions to coastal areas is rarely reported. This study used high-throughput quantitative PCR to examine the diversity and abundance of ARGs in Pearl River Estuary (PRE) and adjacent coastal areas. We found that the distribution of ARGs in seawater exhibited the distance-decay phenomenon from the estuary to coastal areas, while the sediment samples did not exhibit an obvious distribution pattern. The estuarine water was found to be the hotspot of ARGs, with 74 ARG species detected and absolute abundance being 5.93 × 105 copies per mL, on average, while less species and lower abundance of ARGs were detected in coastal waters. Ordination analysis showed that estuarine ARG communities were significantly different from coastal ARG communities for water samples. SourceTracker analysis revealed that ARGs from the estuarine environment contributed only a minor fraction of ARG contamination to downstream coastal areas (1.5%-7.4% for water samples, and 0.7-1.8% for sediment samples), indicating the strong dilution effect of seawater. Mantel tests, redundancy analysis and random forest model analysis identified salinity, nutrients, microbial community structure and mobile genetic elements (MGEs) as important factors influencing ARG distribution. Partial least squares-path model revealed that, among all environmental factors, MGEs directly affected the distribution of ARGs, while other factors indirectly contributed by affecting the MGEs assemblage. Our study provides insight into the dissemination of ARGs from the PRE to adjacent coastal areas.

Salipiger pentaromativorans sp. nov., a polycyclic aromatic hydrocarbon-degrading bacterium isolated from mangrove sediment.

Polycyclic aromatic hydrocarbons (PAHs) have been recognized as a potential health risk and are widespread in nature due to their intrinsic chemical stability and high recalcitrance to degradation. A taxonomic study was carried out on strain P9T, which was isolated from a PAH-degrading consortium, enriched from the mangrove sediment from Zhangzhou, PR China. The isolate was chemoheterotrophic, aerobic, Gram-stain-negative, short-rod shaped, and motile by one polar flagellum. Growth was observed at salinities from 0.5-6.0 % (optimum, 3 %), at pH 4-9 (optimum, pH 7) and at 10-41 °C (optimum, 25-30 °C). It did not synthesize bacteriochlorophyll a. Catalase and oxidase activities were positive. Acid was produced from starch, amygdalin, arbutin, cellobiose, d-fructose, maltose, d-mannitol, melezitose, melibiose, raffinose, d-ribose, sucrose, trehalose, d-xylose, aesculin ferric citrate, gentiobiose, glycogen, l-arabinose, l-rhamnose, methyl α-d-glucopyranoside, methyl ß-d-xylopyranoside, N-acetylglucosamine and salicin, and weakly positive for d-arabitol, d-galactose, lactose, turanose and glycerol. Phylogenetic analysis revealed that strain P9T fell within the clade comprising the type strains of Salipiger species and formed an independent cluster with Salipiger profundus, which was distinct from other members of the family Rhodobacteraceae. The 16S rRNA gene sequence comparisons showed that strain P9T was most closely related to Salipiger bermudensis HTCC 260T (96.7 %), and other species of the genus Salipiger (95.7-94.2 %). Strain P9T had the highest digital DNA-DNA hybridization value with S. profundus CGMCC 1.12377T (25.0 %) and the highest average nucleotide identity (ANIb and ANIm) values with S. profundus CGMCC 1.12377T(80.3 and 85.8 %, respectively). The sole respiratory quinone was quinone 10. The dominant fatty acids were C18 : 1 ω7c (61.4 %), C16 : 0 (17.5 %) and C19 : 0 ω8c cyclo (7.6 %). The G+C content of the chromosomal DNA was 65.8 mol%. In the polar lipid profile, phospholipid, phosphatidylglycerol, aminolipid, glycolipid and phosphatidylethanolamine were the major compounds. Based on the phenotypic and phylogenetic data, strain P9T represents a novel species of the genus Salipiger, for which the name Salipiger pentaromativorans sp. nov. is proposed. The type strain is P9T (=CCTCC AB 209290T=LMG 25701T=MCCC 1F01055T).