ABSTRACT
Many behaviors require the coordinated actions of somatic and autonomic functions. However, the underlying mechanisms remain elusive. By opto-stimulating different populations of descending spinal projecting neurons (SPNs) in anesthetized mice, we show that stimulation of excitatory SPNs in the rostral ventromedial medulla (rVMM) resulted in a simultaneous increase in somatomotor and sympathetic activities. Conversely, opto-stimulation of rVMM inhibitory SPNs decreased both activities. Anatomically, these SPNs innervate both sympathetic preganglionic neurons and motor-related regions in the spinal cord. Fiber-photometry recording indicated that the activities of rVMM SPNs correlate with different levels of muscle and sympathetic tone during distinct arousal states. Inhibiting rVMM excitatory SPNs reduced basal muscle and sympathetic tone, impairing locomotion initiation and high-speed performance. In contrast, silencing the inhibitory population abolished muscle atonia and sympathetic hypoactivity during rapid eye movement (REM) sleep. Together, these results identify rVMM SPNs as descending spinal projecting pathways controlling the tone of both the somatomotor and sympathetic systems.
Subject(s)
Medulla Oblongata , Spinal Cord , Sympathetic Nervous System , Animals , Male , Mice , Locomotion/physiology , Medulla Oblongata/physiology , Mice, Inbred C57BL , Motor Neurons/physiology , Neurons/physiology , Sleep, REM/physiology , Spinal Cord/physiology , Sympathetic Nervous System/physiology , Behavior, Animal , Cell Count , Muscle, SkeletalABSTRACT
The brain controls nearly all bodily functions via spinal projecting neurons (SPNs) that carry command signals from the brain to the spinal cord. However, a comprehensive molecular characterization of brain-wide SPNs is still lacking. Here we transcriptionally profiled a total of 65,002 SPNs, identified 76 region-specific SPN types, and mapped these types into a companion atlas of the whole mouse brain1. This taxonomy reveals a three-component organization of SPNs: (1) molecularly homogeneous excitatory SPNs from the cortex, red nucleus and cerebellum with somatotopic spinal terminations suitable for point-to-point communication; (2) heterogeneous populations in the reticular formation with broad spinal termination patterns, suitable for relaying commands related to the activities of the entire spinal cord; and (3) modulatory neurons expressing slow-acting neurotransmitters and/or neuropeptides in the hypothalamus, midbrain and reticular formation for 'gain setting' of brain-spinal signals. In addition, this atlas revealed a LIM homeobox transcription factor code that parcellates the reticulospinal neurons into five molecularly distinct and spatially segregated populations. Finally, we found transcriptional signatures of a subset of SPNs with large soma size and correlated these with fast-firing electrophysiological properties. Together, this study establishes a comprehensive taxonomy of brain-wide SPNs and provides insight into the functional organization of SPNs in mediating brain control of bodily functions.
Subject(s)
Brain , Gene Expression Profiling , Neural Pathways , Neurons , Spinal Cord , Animals , Mice , Hypothalamus , Neurons/metabolism , Neuropeptides , Spinal Cord/cytology , Spinal Cord/metabolism , Brain/cytology , Brain/metabolism , Neurotransmitter Agents , Mesencephalon/cytology , Reticular Formation/cytology , Electrophysiology , Cerebellum/cytology , Cerebral Cortex/cytologyABSTRACT
BACKGROUND: Data from trials investigating the effects and risks of endovascular thrombectomy for the treatment of stroke due to basilar-artery occlusion are limited. METHODS: We conducted a multicenter, prospective, randomized, controlled trial of endovascular thrombectomy for basilar-artery occlusion at 36 centers in China. Patients were assigned, in a 2:1 ratio, within 12 hours after the estimated time of basilar-artery occlusion to receive endovascular thrombectomy or best medical care (control). The primary outcome was good functional status, defined as a score of 0 to 3 on the modified Rankin scale (range, 0 [no symptoms] to 6 [death]), at 90 days. Secondary outcomes included a modified Rankin scale score of 0 to 2, distribution across the modified Rankin scale score categories, and quality of life. Safety outcomes included symptomatic intracranial hemorrhage at 24 to 72 hours, 90-day mortality, and procedural complications. RESULTS: Of the 507 patients who underwent screening, 340 were in the intention-to-treat population, with 226 assigned to the thrombectomy group and 114 to the control group. Intravenous thrombolysis was used in 31% of the patients in the thrombectomy group and in 34% of those in the control group. Good functional status at 90 days occurred in 104 patients (46%) in the thrombectomy group and in 26 (23%) in the control group (adjusted rate ratio, 2.06; 95% confidence interval [CI], 1.46 to 2.91, P<0.001). Symptomatic intracranial hemorrhage occurred in 12 patients (5%) in the thrombectomy group and in none in the control group. Results for the secondary clinical and imaging outcomes were generally in the same direction as those for the primary outcome. Mortality at 90 days was 37% in the thrombectomy group and 55% in the control group (adjusted risk ratio, 0.66; 95% CI, 0.52 to 0.82). Procedural complications occurred in 14% of the patients in the thrombectomy group, including one death due to arterial perforation. CONCLUSIONS: In a trial involving Chinese patients with basilar-artery occlusion, approximately one third of whom received intravenous thrombolysis, endovascular thrombectomy within 12 hours after stroke onset led to better functional outcomes at 90 days than best medical care but was associated with procedural complications and intracerebral hemorrhage. (Funded by the Program for Innovative Research Team of the First Affiliated Hospital of USTC and others; ATTENTION ClinicalTrials.gov number, NCT04751708.).
Subject(s)
Arterial Occlusive Diseases , Basilar Artery , Endovascular Procedures , Stroke , Thrombectomy , Humans , Administration, Intravenous , Arterial Occlusive Diseases/complications , Arterial Occlusive Diseases/drug therapy , Arterial Occlusive Diseases/mortality , Arterial Occlusive Diseases/surgery , Basilar Artery/drug effects , Basilar Artery/surgery , Brain Ischemia/drug therapy , Brain Ischemia/etiology , Brain Ischemia/surgery , Endovascular Procedures/adverse effects , Endovascular Procedures/methods , Fibrinolytic Agents/administration & dosage , Fibrinolytic Agents/adverse effects , Fibrinolytic Agents/therapeutic use , Intracranial Hemorrhages/chemically induced , Intracranial Hemorrhages/etiology , Prospective Studies , Quality of Life , Stroke/drug therapy , Stroke/etiology , Stroke/mortality , Stroke/surgery , Thrombectomy/adverse effects , Thrombectomy/methods , Thrombolytic Therapy/adverse effects , Thrombolytic Therapy/methods , Treatment Outcome , Recovery of FunctionABSTRACT
Cholecystokinin (CCK) enables excitatory circuit long-term potentiation (LTP). Here, we investigated its involvement in the enhancement of inhibitory synapses. Activation of GABA neurons suppressed neuronal responses in the neocortex to a forthcoming auditory stimulus in mice of both sexes. High-frequency laser stimulation (HFLS) of GABAergic neurons potentiated this suppression. HFLS of CCK interneurons could induce the LTP of their inhibition toward pyramidal neurons. This potentiation was abolished in CCK knock-out mice but intact in mice with both CCK1R and 2R knockout of both sexes. Next, we combined bioinformatics analysis, multiple unbiased cell-based assays, and histology examinations to identify a novel CCK receptor, GPR173. We propose GPR173 as CCK3R, which mediates the relationship between cortical CCK interneuron signaling and inhibitory LTP in the mice of either sex. Thus, GPR173 might represent a promising therapeutic target for brain disorders related to excitation and inhibition imbalance in the cortex.SIGNIFICANCE STATEMENT CCK, the most abundant and widely distributed neuropeptide in the CNS, colocalizes with many neurotransmitters and modulators. GABA is one of the important inhibitory neurotransmitters, and much evidence shows that CCK may be involved in modulating GABA signaling in many brain areas. However, the role of CCK-GABA neurons in the cortical microcircuits is still unclear. We identified a novel CCK receptor, GPR173, localized in the CCK-GABA synapses and mediated the enhancement of the GABA inhibition effect, which might represent a promising therapeutic target for brain disorders related to excitation and inhibition imbalance in the cortex.
Subject(s)
GABA Agents , Receptors, Cholecystokinin , Male , Female , Mice , Animals , GABA Agents/pharmacology , Pyramidal Cells/physiology , Synapses/physiology , GABAergic Neurons/physiology , Mice, Knockout , Interneurons , Cholecystokinin , gamma-Aminobutyric Acid/physiology , Long-Term Potentiation/physiology , Receptors, G-Protein-Coupled/geneticsABSTRACT
The cortical distribution and functional role of cholecystokinin (CCK) are largely unknown. Here, a CCK receptor antagonist challenge paradigm was developed to assess functional connectivity and neuronal responses. Structural-functional magnetic resonance imaging and calcium imaging were undertaken in environmental enrichment (EE) and standard environment (SE) groups (naïve adult male mice, n = 59, C57BL/B6J, P = 60). Functional connectivity network-based statistics and pseudo-demarcation Voronoi tessellations to cluster calcium signals were used to derive region of interest metrics based on calcium transients, firing rate, and location. The CCK challenge elicited robust changes to structural-functional networks, decreased neuronal calcium transients, and max firing rate (5 s) of dorsal hippocampus in SE mice. However, the functional changes were not observed in EE mice, while the decreased neuronal calcium transients and max firing rate (5 s) were similar to SE mice. Decreased gray matter alterations were observed in multiple brain regions in the SE group due to CCK challenge, while no effect was observed in the EE group. The networks most affected by CCK challenge in SE included within isocortex, isocortex to olfactory, isocortex to striatum, olfactory to midbrain, and olfactory to thalamus. The EE group did not experience network changes in functional connectivity due to CCK challenge. Interestingly, calcium imaging revealed a significant decrease in transients and max firing rate (5 s) in the dorsal CA1 hippocampus subregion after CCK challenge in EE. Overall, CCK receptor antagonists affected brain-wide structural-functional connectivity within the isocortex, in addition to eliciting decreased neuronal calcium transients and max firing rate (5 s) in CA1 of the hippocampus. Future studies should investigate the CCK functional networks and how these processes affect isocortex modulation. Significance Statement Cholecystokinin is a neuropeptide predominately found in the gastrointestinal system. Albeit abundantly expressed in neurons, the role and distribution of cholecystokinin are largely unknown. Here, we demonstrate cholecystokinin affects brain-wide structural-functional networks within the isocortex. In the hippocampus, the cholecystokinin receptor antagonist challenge decreases neuronal calcium transients and max firing rate (5 s) in CA1. We further demonstrate that mice in environmental enrichment do not experience functional network changes to the CCK receptor antagonist challenge. Environmental enrichment may afford protection to the alterations observed in control mice due to CCK. Our results suggest that cholecystokinin is distributed throughout the brain, interacts in the isocortex, and demonstrates an unexpected functional network stability for enriched mice.
Subject(s)
Cholecystokinin , Connectome , Mice , Male , Animals , Receptors, Cholecystokinin , Calcium , Mice, Inbred C57BL , HippocampusABSTRACT
Zoogloea sp. MFQ7 achieved excellent denitrification of 91.71% at ferrous to manganous ratio (Fe/Mn) of 3:7, pH of 6.5, nitrate concentration of 25 mg L-1 and carbon to nitrogen ratio of 1.5. As the Fe/Mn ratio increasd, the efficiency of nitrate removal gradually decreased, indicating that strain MFQ7 had a higher affinity for Mn2+ than Fe2+. In situ generated biogenic Fe-Mn oxides (BFMO) contained many iron-manganese oxides (MnO2, Mn3O4, FeO(OH), Fe2O3, and Fe3O4) as well as reactive functional groups, which play an significant part in tetracycline (TC) and cadmium (Cd2+) adsorption. The adsorption of TC and Cd2+ by BFMO can better fit the pseudo-second-order and Langmuir models. In addition, multiple characterization results of before and after adsorption indicated that the removal mechanism of BFMO on TC and Cd2+ was probably surface complexation adsorption and redox reactions.
Subject(s)
Cadmium , Ferric Compounds , Oxides , Oxides/chemistry , Nitrates , Manganese Compounds/chemistry , Denitrification , Tetracycline , Anti-Bacterial Agents , Organic Chemicals , AdsorptionABSTRACT
In this experiment, the prepared tea biochar-cellulose@LDH material (TB-CL@LDH) was combined with mycelium pellets to form the composite mycelial pellets (CMP), then assembled and immobilized with strains Pseudomonas sp. Y1 and Cupriavidus sp. ZY7 to construct a bioreactor. At the best operating parameters, the initial concentrations of phosphate (PO43--P), ammonia nitrogen (NH4+-N), chemical oxygen demand (COD), zinc (Zn2+), and phenol were 22.3, 25.0, 763.8, 1.0, and 1.0 mg L-1, the corresponding removal efficiencies were 80.4, 87.0, 83.4, 91.8, and 96.6%, respectively. Various characterization analyses demonstrated that the strain Y1 used the additional carbon source produced by the strain ZY7 degradation of cellulose to enhance the removal of composite pollutants and clarified the principle of Zn2+ and PO43--P removal by adsorption, co-precipitation and biomineralization. Pseudomonas and Cupriavidus were the dominant genera according to the high-throughput sequencing. As shown by KEGG results, nitrification and denitrification genes were affected by phenol. The study offers prospects for the simultaneous removal of complex pollutants consisting of NH4+-N, PO43--P, Zn2+, and phenol.
Subject(s)
Ammonia , Bioreactors , Cellulose , Mycelium , Phenol , Phosphates , Zinc , Bioreactors/microbiology , Cellulose/chemistry , Cellulose/metabolism , Mycelium/metabolism , Phosphates/metabolism , Ammonia/metabolism , Nitrogen/metabolism , Biodegradation, Environmental , Pseudomonas/metabolism , Cupriavidus/metabolism , Cupriavidus/genetics , Water Pollutants, Chemical/analysis , CharcoalABSTRACT
The issue of combined pollution in oligotrophic water has garnered increasing attention in recent years. To enhance the pollutant removal efficiency in oligotrophic water, the system containing Zoogloea sp. FY6 was constructed using polyester fiber wrapped sugarcane biochar and construction waste iron (PWSI), and the denitrification test of simulated water and actual oligotrophic water was carried out for 35 days. The experimental findings from the systems indicated that the removal efficiencies of nitrate (NO3--N), total nitrogen (TN), chemical oxygen demand (COD), and total phosphorus (TP) in simulated water were 88.61%, 85.23%, 94.28%, and 98.90%, respectively. The removal efficiencies of actual oligotrophic water were 83.06%, 81.39%, 81.66%, and 97.82%, respectively. Furthermore, the high-throughput sequencing data demonstrated that strain FY6 was successfully loaded onto the biological carrier. According to functional gene predictions derived from the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, the introduction of PWSI enhanced intracellular iron cycling and nitrogen metabolism.
Subject(s)
Charcoal , Iron , Nitrogen , Phosphorus , Water Pollutants, Chemical , Phosphorus/analysis , Nitrogen/analysis , Nitrogen/metabolism , Charcoal/chemistry , Iron/chemistry , Water Pollutants, Chemical/analysis , Waste Disposal, Fluid/methodsABSTRACT
An Acinetobacter calcoaceticus strain HM12 capable of heterotrophic nitrification-aerobic denitrification (HN-AD) under nutrient-poor conditions was isolated, with an ammonia nitrogen (NH4+-N) removal efficiency of 98.53%. It can also remove heavy metals by microbial induced calcium precipitation (MICP) with a Ca2+ removal efficiency of 75.91%. Optimal conditions for HN-AD and mineralization of the strain were determined by kinetic analysis (pH = 7, C/N = 2.0, Ca2+ = 70.0 mg L-1, NH4+-N = 5.0 mg L-1). Growth curves and nitrogen balance elucidated nitrogen degradation pathways capable of converting NH4+-N to gaseous nitrogen. The analysis of the bioprecipitation showed that Zn2+ and Cd2+ were removed by the MICP process through co-precipitation and adsorption (maximum removal efficiencies of 93.39% and 80.70%, respectively), mainly ZnCO3, CdCO3, ZnHPO4, Zn3(PO4)2 and Cd3(PO4)2. Strain HM12 produces humic and fulvic acids to counteract the toxicity of pollutants, as well as aromatic proteins to increase extracellular polymers (EPS) and promote the biomineralization process. This study provides a experimental evidence for the simultaneous removal of multiple pollutants from nutrient-poor waters.
Subject(s)
Acinetobacter calcoaceticus , Environmental Pollutants , Metals, Heavy , Ammonia , Denitrification , Acinetobacter calcoaceticus/metabolism , Calcium/metabolism , Nitrites/metabolism , Kinetics , Cadmium , Aerobiosis , Nitrification , Nitrogen/analysis , Heterotrophic Processes , NutrientsABSTRACT
With the enhancement of environmental governance regulations, the discharge requirements for reverse osmosis wastewater have become increasingly stringent. This study proposes an innovative approach utilizing heterotrophic nitrification and aerobic denitrification (HNAD)-based biomineralization technology, combined with coconut palm silk loaded biochar, to offer a novel solution for resource-efficient and eco-friendly treatment of reverse osmosis wastewater. Zobellella denitrificans sp. LX16 were loaded onto modified coir silk and showed removal efficiencies of up to 97.38, 94.58, 86.24, and 100% for NH4+-N (65 mg L-1), COD (900 mg L-1), Ca2+ (180 mg L-1), and Cd2+ (25 mg L-1). Analysis of the metabolites of microorganisms reveals that coconut palm silk loaded with deciduous biochar (BCPS) not only exerts a protective effect on microorganisms, but also enhances their growth, metabolism, and electron transfer capabilities. Characterization of precipitation phenomena elucidated the mechanism of Cd2+ removal via ion exchange, precipitation, and adsorption. Employing high-throughput and KEGG functional analyses has confirmed the biota environmental response strategies and the identification of key genes like HNAD.
Subject(s)
Ammonia , Biofilms , Bioreactors , Cadmium , Calcium , Nitrogen , Cadmium/metabolism , Calcium/metabolism , Ammonia/metabolism , Nitrogen/metabolism , Wastewater/chemistry , Denitrification , Charcoal/chemistry , Waste Disposal, Fluid/methodsABSTRACT
BACKGROUND: The authors compare the effectiveness and safety of endovascular treatment (EVT) versus best medical management (BMM) in strokes attributable to acute basilar artery occlusion (BAO). METHODS: The present analysis was based on the ongoing, prospective, multicenter ATTENTION (Endovascular Treatment for Acute Basilar Artery Occlusion) trial registry in China. Our analytic sample comprised 2134 patients recruited at 48 sites between 2017 and 2021 and included 462 patients who received BMM and 1672 patients who received EVT. We performed an inversed probability of treatment weighting analysis. Qualifying patients had to present within 24 hours of estimated BAO. The primary clinical outcome was favorable functional outcome (modified Rankin Scale score, 0-3) at 90 days. We also performed a sensitivity analysis with the propensity score matching-based and the instrumental variable-based analysis. RESULTS: In our primary analysis using the inversed probability of treatment weighting-based analysis, there was a significantly higher rate of favorable outcome at 90 days among EVT patients compared with BMM-treated patients (adjusted relative risk, 1.42 [95% CI, 1.19-1.65]; absolute risk difference, 11.8% [95% CI, 6.9-16.7]). The mortality was significantly lower (adjusted relative risk, 0.78 [95% CI, 0.69-0.88]; absolute risk difference, -10.3% [95% CI, -15.8 to -4.9]) in patients undergoing EVT. Results were generally consistent across the secondary end points. Similar associations were seen in the propensity score matching-based and instrumental variable-based analysis. CONCLUSIONS: In this real-world study, EVT was associated with significantly better functional outcomes and survival at 90 days. Well-designed randomized studies comparing EVT with BMM in the acute BAO are needed. REGISTRATION: URL: www.chictr.org.cn; Unique identifier: ChiCTR2000041117.
Subject(s)
Arterial Occlusive Diseases , Endovascular Procedures , Stroke , Arterial Occlusive Diseases/therapy , Basilar Artery , Endovascular Procedures/adverse effects , Endovascular Procedures/methods , Humans , Prospective Studies , Registries , Thrombectomy/methods , Treatment OutcomeABSTRACT
Based on the current situation of complex pollution caused in surface water by oligotrophic condition and heavy metal release from river and lake bottom sediments. This study aimed to achieve the simultaneous removal of nitrate, phosphorus, Zn2+ and Pb2+ through microbial approach. At nitrate concentration of 4.82 mg L-1, carbon to nitrogen ratio of 1.5, pH of 6.0, and Fe2+ concentration of 5.0 mg L-1, the nitrate removal efficiency of Zoogloea sp. FY-6 reached 95.17%. The addition of pollutants under these conditions resulted in 88.76% removal of total phosphorus at 18 h, and 85.46 and 78.59% removal of Zn2+ and Pb2+ respectively, and there was competition for adsorption between Zn2+ and Pb2+. Extracellular polymers and fluorescence excitation-emission substrates confirmed that Fe2+ reduced heavy metal toxicity through promoting bacterial production of secretions and promotes denitrification as a carbon source. Meanwhile, contaminant removal curves and Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy demonstrated the synchronous removal of Zn2+ and Pb2+ mainly through biological action and the formation of nanoscale iron oxides. Biological-iron precipitation also provided adsorption sites for phosphorus. This research provides the theoretical foundation for applying microorganisms to restore oligotrophic source water (rivers and lakes) containing complex pollutants.
Subject(s)
Environmental Pollutants , Metals, Heavy , Iron/chemistry , Zinc , Lead , Phosphorus , Nitrates , Denitrification , Ecosystem , Metals, Heavy/chemistry , Carbon , Water , NitrogenABSTRACT
Composite pollutants are prevalent in wastewater, whereas, the simultaneous accomplishment of efficient nitrogen removal and resources recovery remains a challenge. In this study, a bioreactor was constructed to contain Pseudomonas sp. Y1 using polyester fiber wrapped with shell powder and iron carbon spheres, achieving ammonia nitrogen (NH4+-N) removal, phosphate (PO43--P) recovery, and nickel (Ni2+) immobilization. The optimal performance of bioreactor was average removal efficiencies of NH4+-N, PO43--P, calcium (Ca2+), and Ni2+ as 82.42, 96.67, 76.13, and 98.29% at a hydraulic retention time (HRT) of 6 h, pH of 7.0, and influent Ca2+ and Ni2+ concentrations of 100.0 and 3.0 mg L-1, respectively. The bioreactor could remove PO43--P, Ca2+, and Ni2+ by biomineralization, co-precipitation, adsorption, and lattice substitution. Moreover, microbial community analysis suggested that Pseudomonas was the predominant genus and had possessed tolerance to Ni2+ toxicity in wastewater. This study presented an effective method to synchronously remove NH4+-N, recover PO43--P, and fix heavy metals through microbially induced carbonate precipitation (MICP) and heterotrophic nitrification and aerobic denitrification (HNAD) technology.
Subject(s)
Ammonia , Wastewater , Phosphates , Denitrification , Nickel , Powders , Iron , Carbon , Nitrogen/metabolism , Bioreactors , AerobiosisABSTRACT
There is an urgent demand to investigate mechanisms for the improvement of denitrification in carbon-deficient environment, which will effectively reduce the eutrophication in water bodies polluted by nitrate. In this study, denitrifying bacterium Comamonas sp. YSF15 was used to explore the differences in different carbon source concentrations, with the complete genome, metabolomics, and other detecting methods. Results showed that strain YSF15 was able to achieve efficient denitrification, with complete pathways for denitrification and central carbon metabolism. The carbon deficiency prompted the bacteria to use extracellular amino acid-like metabolites initially, to alleviate inhibition and maintain bioactivity, which also facilitated glycogen storage. The biogenic inhibitors (tautomycin, navitoclax, and glufosinate) at extremely low level potentially favored the competitiveness and intraspecific utilization of extracellular polysaccharides (PS). Optimal solutions for bioaggregation in carbon-deficient condition are achieved by regulating the hydrophobicity, and hydrogen bond in extracellular metabolites. The strategy contributes to the maintenance of bioactivity and adaptation to carbon deficiency. Overall, this study provides a new perspective on understanding the denitrification strategies in carbon-deficient environment, and helps to improve the nitrate removal in low-carbon wastewater treatment.
Subject(s)
Comamonas , Wastewater , Nitrates/analysis , Comamonas/metabolism , Denitrification , Carbon/chemistry , Nitrogen/metabolism , Bacteria/metabolism , Bioreactors/microbiologyABSTRACT
The pollution problem of oxytetracycline (OTC) from wastewater becomes more serious, so an efficient, economical, and green adsorption material is urgently explored. In this study, the multilayer porous biochar (OBC) was prepared by coupling carbon nanotubes with iron oxide nanoparticles synthesized by Aquabacterium sp. XL4 to modify corncobs under medium temperature (600 °C) conditions. The adsorption capacity of OBC could reach 72.59 mg g-1 after preparation and operation parameters were optimized. In addition, various adsorption models suggested that OTC removal resulted from the combined effect of chemisorption, multilayer interaction, and disordered diffusion. Meanwhile, the OBC was fully characterized and exhibited a large specific surface area (237.51 m2 g-1), abundant functional groups, stable crystal structure, high graphitization, and mild magnetic properties (0.8 emu g-1). The OTC removal mechanisms mainly included electrostatic interactions, ligand exchange, π-π bonding reactions, hydrogen bonds, and complexation. pH and coexistence substance experiments revealed that the OBC possesses a wide pH adaptation range and excellent anti-interference ability. Finally, the safety and reusability of OBC were confirmed by repeated experiments. In summary, OBC as a biosynthetic material shows considerable potential for application in the field of purifying new pollution from wastewater.
Subject(s)
Nanotubes, Carbon , Oxytetracycline , Water Pollutants, Chemical , Oxytetracycline/chemistry , Wastewater , Adsorption , Magnetic Iron Oxide Nanoparticles , Water Pollutants, Chemical/analysis , KineticsABSTRACT
In recent years, under the condition of lack of carbon source, the presence of composite micro-pollutants make the removal of nitrate seriously damaged, and to find a suitable way to solve this problem is imminent. A fixed-biofilm carrier modified by mixing sponge iron (SI) and kapok fiber (KF) combined with strain Zoogloea sp. FY6 was constructed in this study to get a fixed-biofilm reactor with merit denitrification performance. By adjusting the operation parameters, it can be concluded that when the carbon to nitrogen (C/N) ratio was 1.5, the hydraulic retention time (HRT) was 6.0 h, and the pH was 6.0, the nitrate removal efficiency (NRE) of the fixed-biofilm reactor was up to 95.4% (2.95 mg L-1 h-1). In addition, the fixed-biofilm reactor constructed in this study can remove lead (Pb2+) and tetracycline (TC) excellently in the presence of SI and Zoogloea sp. FY6, and the denitrification performance can still maintain a high level under the influence of different concentrations of Pb2+ and TC. Furthermore, the addition of SI not only removes the compound pollutants, but also protects the toxicity of the pollutant inflow in the bioreactor, and the metabolic process of microorganisms in the bioreactor also removes some of the compound pollutants. The high-throughput data showed the abundance of strain Zoogloea sp. FY6 was still the highest value under the influence of various pollutants, and the metagenomic prediction showed that the fixed-biofilm reactor had perfect denitrification process and iron redox cycle benefits. This study provides a valuable reference for sustainable utilization of natural biological resources and reduction of material costs in wastewater treatment plants (WWTPs).
Subject(s)
Iron , Nitrates , Lead , Tetracycline , Anti-Bacterial Agents , Biofilms , Carbon , Biota , Bioreactors , NitrogenABSTRACT
The template method is an effective means to improve the specific surface area and porosity of biochar, but the synthesis of template agents and the way they are integrated with biomass materials still need further development. Therefore, the free Pseudomonas sp. Y1 was used to synthesize calcium-precipitated nanoparticles (CPN) on sludge as a fused template skeleton to enlarge the surface area of sludge biochar facilitating the adsorption of tetracycline (TC) in this work. The modified biochar (FBC) showed excellent specific surface area (448.55 m2 g-1) and porosity (0.0053 cm³ g-1), stable morphological structure, abundant active functional groups, and appreciable adsorption capacity (65.43 mg g-1) based on several characterization and adsorption experiments. Moreover, the adsorption model postulated that the removal of TC is mainly a chemisorption-based heat-trapping, disordered multilayer interaction. In detail, this process involved the joint contribution from electrostatic interactions, ligand exchange, hydrogen bonding, π-π bonding, complexation, and pore filling. Meanwhile, the adaptability and stability of FBC were examined by pH and coexisting substances. This template skeleton induced by microorganisms can provide new insight into the modification of biochar with the template method.
Subject(s)
Nanoparticles , Water Pollutants, Chemical , Calcium , Water , Sewage , Anti-Bacterial Agents , Tetracycline/chemistry , Charcoal/chemistry , Skeleton/chemistry , Adsorption , Water Pollutants, Chemical/analysis , KineticsABSTRACT
The composite mycelium pellet (CMP) was coupled with Pseudomonas sp. Y1 (CMP-Y1) to remove phenol and ammonia nitrogen (NH4+-N). The CMP was formed by the self-assembly of fungal mycelium with sponge iron (SIO), gallic acid (GA), and oxalic acid. The results showed that CMP with abundant pore size and successful internal loading of sponge iron containing iron nanoparticles. CMP could induce GA redox cycle to form Fenton-like reaction and thus achieve efficient phenol removal (93.32%, 24 h). Meanwhile, the removal efficiencies of phenol, NH4+-N, and chemical oxygen demand (COD) using CMP-Y1 at 12 h were 93.71, 92.40, and 89.00%, respectively. The increase in the electron transfer activity of strain Y1 by the addition of CMP could facilitate the nitrogen removal processes. In addition, high-throughput sequencing results indicated the abundance of antioxidant and repair genes was increased, which might be a strategy of strain Y1 to cope with oxidative stress. This strategy provided the possibility for the practical application of the combination of advanced oxidation and biological treatment, and offered new insights into the symbiotic system of fungi and bacteria.
Subject(s)
Ammonia , Phenol , Phenols , Quinones , Oxidation-Reduction , Bacteria , Gallic Acid , Iron , MyceliumABSTRACT
Microbially induced calcium precipitation (MICP) driven by denitrification has attracted extensive attention due to its application potential in nitrate removal from calcium-rich groundwater. However, little research has been conducted on this technique at the molecular level. Here, Pseudomonas WZ39 was used to explore the molecular mechanisms of nitrate-dependent MICP and the effects of Ca2+ on bacterial transcriptional regulation and metabolic response. The results exhibited that appropriate Ca2+ concentration (4.5 mM) can promote denitrification and the production of ATP, EPSs, and SMPs. Genome-wide analysis showed that the nitrate-dependent MICP was accomplished through heterotrophic denitrification and CO2 capture. During this process, EPS biosynthesis and Ca2+ signaling regulation were involved in the nucleation template supply and Ca2+ homeostasis balance. Untargeted transcriptome- and metabolome-association analyses revealed that the addition of Ca2+ triggered the significant up-regulation in several key pathways, such as transmembrane transporter and channel activities, amino acid metabolism, fatty acid biosynthesis, and carbon metabolism, which played a momentous role in the mineral nucleation and energy provision. The detailed information provided novel insights for understanding the active control of bacteria on MICP, and has great significance for deepening the cognition of groundwater remediation using nitrate-dependent MICP technique.
Subject(s)
Calcium Carbonate , Calcium , Calcium/metabolism , Calcium Carbonate/chemistry , Nitrates , Denitrification , Bacteria/metabolism , Chemical PrecipitationABSTRACT
Environmental enrichment induces widespread neuronal changes, but the initiation of the cascade is unknown. We ascertained the critical period of divergence between environmental enriched (EE) and standard environment (SE) mice using continuous infrared (IR) videography, functional magnetic resonance imaging (fMRI), and neuron level calcium imaging. Naïve adult male mice (n = 285, C57BL/6J, postnatal day 60) were divided into SE and EE groups. We assessed the linear time-series of motion activity using a novel structural break test which examined the dataset for change in circadian and day-by-day motion activity. fMRI was used to map brain-wide response using a functional connectome analysis pipeline. Awake calcium imaging was performed on the dorsal CA1 pyramidal layer. We found the preeminent behavioral feature in EE was a forward shift in the circadian rhythm, prolongation of activity in the dark photoperiod, and overall decreased motion activity. The crepuscular period of dusk was seen as the critical period of divergence between EE and SE mice. The functional processes at dusk in EE included increased functional connectivity in the visual cortex, motor cortex, retrosplenial granular cortex, and cingulate cortex using seed-based analysis. Network based statistics found a modulated functional connectome in EE concentrated in two hubs: the hippocampal formation and isocortical network. These hubs experienced a higher node degree and significant enhanced edge connectivity. Calcium imaging revealed increased spikes per second and maximum firing rate in the dorsal CA1 pyramidal layer, in addition to location (anterior-posterior and medial-lateral) effect size differences between EE and SE. The emergence of functional-neuronal changes due to enrichment consisted of enhanced hippocampal-isocortex functional connectivity and CA1 neuronal increased spiking linked to a circadian shift during the dusk period. Future studies should explore the molecular consequences of enrichment inducing shifts in the circadian period.