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1.
Bioresour Technol ; 371: 128645, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36681349

RESUMO

The lack of anammox seeds is regarded as the bottleneck of anammox-based processes. Although the interactions in anammox consortia have attracted increasing attention, little is known about the influence of inoculated sludge populations on the growth of anammox bacteria. In this study, four sludge of distinct communities mixed with anammox sludge (the relative abundance of Ca. Kuenenia was 1.96 %) were used as the seeds, respectively for the start-up of anammox processes. Notably, all these mixed microbial communities tend to form a similar microbial community, defined as the anammox core, containing anammox-bacteria (22.9 ± 5.9 %), ammonia-oxidizing-bacteria (0.8 ± 0.7 %), nitrite-oxidizing-bacteria (0.2 ± 0.2 %), Chloroflexi-bacteria (0.7 ± 0.4 %), and heterotrophic-denitrification-bacteria (0.3 ± 0.2 %). It also elucidated that the communities of Nitrosomonas-dominated sludge were the closest to the anammox core, and achieved the highest nitrogen-removal rate of 0.73 kg-N m-3 d-1. This study sheds light on the solution to the shortage of anammox seeds in the full-scale wastewater treatment application.


Assuntos
Microbiota , Esgotos , Esgotos/microbiologia , Oxidação Anaeróbia da Amônia , Reatores Biológicos/microbiologia , Oxirredução , Bactérias , Nitrogênio , Desnitrificação
2.
Int J Biol Macromol ; 2022 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-36455823

RESUMO

Open poly(3-hydroxybutyrate) (PHB) fermentation is of great potential, and batch PHB synthesis with piperazine as the nitrogen switch has been realized. However, it is vital to explore the feasibility of continuous PHB fermentation with piperazine-contained wastewater remediation collaboratively. Here, an aerobic membrane bioreactor was constructed for consecutive PHB synthesis. The removal efficiency of piperazine decreased from 100 % to 82.6 % after three cycles, meanwhile, the PHB concentration was 0.39 g·L-1, 0.18 g·L-1, and undetected for each cycle. Microbial community analysis showed that Proteobacteria, Actinobacteriota, and Bacteroidota were the main contaminating microbes. Furthermore, three metagenome-assembled genomes related to Flavobacterium collumnare, Herbaspirillum aquaticum, and Microbacterium enclense were identified as the dominant contaminating strains. These microbes obtained nitrogenous substrates transformed by Paracoccus sp. TOH, such as amino acids and dissolved organic matter, as nutrient for accumulation. This study verified the practicability of coupling continuous PHB synthesis with industrial wastewater treatment and revealed the derivation mechanism of contaminating species, which could provide a reference for the targeted nitrogen release gene knockout of functional PHB fermentation chassis.

3.
ACS Omega ; 7(42): 38084-38093, 2022 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-36312435

RESUMO

A highly chemoselective reaction between α,ß-unsaturated trifluoromethyl ketones with azaarenes under metal-free conditions was carried out, affording a range of valuable azaarene-equipped CF3-tertiary alcohols in moderate to excellent yields (up to 95% yield) with good tolerance of functional groups, and their structures were confirmed by NMR, HRMS, and X-ray diffraction for validation. This method features simple reaction conditions (only solvent), high atom- and step-economy, and broad substrate scope. Moreover, most of the target products exhibited promising fungicidal activities, and compound 3al exhibited 91.65% fungicidal activity against R. solani, with an EC50 value of 0.18 mg/mL.

4.
Org Biomol Chem ; 20(44): 8747-8755, 2022 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-36314252

RESUMO

A novel approach for converting N-substituted acetylpyrroles and primary alcohols into N-substituted pyrrolyl chalcones in air with the assistance of t-BuOK is reported, and several prominent flavor and bioactive molecules were obtained. The process entails oxidizing the alcohols to the corresponding aldehydes, and t-BuOK is crucial to the effective production of CC bonds by aldol condensation. Gas chromatography-mass spectrometry-olfactometry (GC-MS-O) was used to examine the odor properties of pyrrolyl chalcones, which are usually different from those of the associated acetylpyrroles and alcohols. The biological evaluation assay showed that the products (E)-3-(3-fluorophenyl)-1-(1-methyl-1H-pyrrol-2-yl)prop-2-en-1-one (3j), (E)-1-(1-ethyl-1H-pyrrol-2-yl)-3-phenylprop-2-en-1-one (4a), (E)-3-(4-bromophenyl)-1-(1-ethyl-1H-pyrrol-2-yl)prop-2-en-1-one (4e), (E)-3-(4-chlorophenyl)-1-(1-ethyl-1H-pyrrol-2-yl)prop-2-en-1-one (4f) and (E)-1-(1-ethyl-1H-pyrrol-2-yl)-3-(4-fluorophenyl)prop-2-en-1-one (4g) exhibited excellent inhibitory activity against R. solani with EC50 values from 0.0107 to 0.0134 mg mL-1. Molecular docking of 3j with SDH (succinate dehydrogenase) was performed to reveal the binding modes in the active pocket and analyze the interactions between the molecules and the SDH protein. Meanwhile, they have good thermal stability according to the results of thermogravimetry (TG) analysis.


Assuntos
Chalcona , Chalconas , Chalconas/química , Simulação de Acoplamento Molecular , Odorantes , Álcoois
5.
Water Res ; 226: 119269, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36279615

RESUMO

Biological nitrogen removal (BNR) is one of the most important environmental concerns in the field of wastewater treatment. The conventional BNR process based on heterotrophic nitrogen removal (HeNR) is suffering from several limitations, including external carbon source dependence, excessive sludge production, and greenhouse gas emissions. Through the mediation of autotrophic nitrogen removal (AuNR), mixed/mixotrophic nitrogen removal (MixNR) offers a viable solution to the optimization of the BNR process. Here, the recent advance and characteristics of MixNR process guided by sulfur-driven autotrophic denitrification (SDAD) and anammox are summarized in this review. Additionally, we discuss the functional microorganisms in different MixNR systems, shedding light on metabolic mechanisms and microbial interactions. The significance of MixNR for carbon reduction in the BNR process has also been noted. The knowledge gaps and the future research directions that may facilitate the practical application of the MixNR process are highlighted. Overall, the prospect of the MixNR process is attractive, and this review will provide guidance for the future implementation of MixNR process as well as deciphering the microbially metabolic mechanisms.


Assuntos
Nitrogênio , Desnitrificação , Reatores Biológicos , Oxirredução , Processos Autotróficos , Carbono , Nitratos/metabolismo
6.
J Environ Manage ; 324: 116262, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36183528

RESUMO

The engineering applications of mainstream anaerobic ammonium oxidation (anammox) have raised increasing attention due to its energy-efficient, however, the organics-mediated microbial dynamics and mixotrophic metabolisms in anammox consortia under micro-aerobic conditions are still elusive. Here, the response of the anammox process to sodium acetate and glucose at a C/N ratio ranging from 0 to 0.5 was investigated under micro-aerobic conditions, respectively. Results showed that the additional glucose could promote the nitrogen removal efficiency (NRE) and nitrogen removal rate (NRR) of anammox processes at a low C/N ratio (0.3), representing 84.00% and 0.53 N kg·m-3·d-1. The introduced organics could regulate the diversity of the microbial community and simplify the microbial relationship in anammox consortia. Anammox could not benefit from the introduced sodium acetate, while glucose could effectively enhance the anammox activity and microbial interactions in anammox consortia. Glucose might also stimulate the mixotrophic mechanism of Ca. Kuenenia, further promotes the proliferation of anammox sludge under micro-aerobic conditions. This study reveals that glucose could positively mediate microbial interactions and mixotrophic metabolism in anammox consortia under micro-aerobic conditions, which raises a new horizon for the proliferation of anammox sludge for mainstream engineering applications.


Assuntos
Compostos de Amônio , Esgotos , Compostos de Amônio/metabolismo , Reatores Biológicos , Acetato de Sódio , Oxirredução , Nitrogênio/metabolismo , Anaerobiose , Glucose , Desnitrificação
7.
Bioresour Technol ; 363: 127939, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36100183

RESUMO

The expensive carbon matrix is a bottleneck restricting the industrialization of polyhydroxyalkanoates (PHAs). Volatile fatty acids (VFAs) derived from waste activated sludge via anaerobic fermentation might be alternative carbon matters for PHAs synthesis. In this study, the effect of enzymes on VFAs yields and the feasibility of the produced VFAs for PHAs fermentation by Paracoccus sp. TOH were investigated. The optimum cumulative VFAs concentration reached 4076.6 mg-COD·L-1 in the lysozyme treatment system. Correspondingly, the highest poly(3-hydroxybuturate-co-3-hydroxyvalerate) (PHBV) concentration (119.1 mg·L-1) containing 20.3 mol% 3-hydroxyvalerate was obtained. It proved that Paracoccus sp. TOH possesses the capability for PHBV accumulation. The functional hydrolytic-acidogenic microorganisms, such as Clostridium sensu stricto and Bacteroides sp. were accumulated. The functional genes encoding hydrolysis, carbohydrates metabolism, VFAs generation were enriched. This study offered a possible strategy for VFAs production and verified the feasibility of sludge hydrolysate as a high-quality carbon substrate for PHAs fermentation.


Assuntos
Paracoccus , Poli-Hidroxialcanoatos , Carboidratos/química , Carbono , Ácidos Graxos Voláteis/metabolismo , Fermentação , Concentração de Íons de Hidrogênio , Muramidase/metabolismo , Paracoccus/metabolismo , Ácidos Pentanoicos , Poli-Hidroxialcanoatos/metabolismo , Esgotos/química
8.
Environ Res ; 215(Pt 1): 114318, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36116498

RESUMO

The feasibility of anammox-based processes for nitrogen-contained wastewater treatment has been verified with different anammox bacteria, however, the ecological niche of anammox bacteria under mainstream conditions is still elusive. In this study, six sludge samples collected from different habitats were utilized to culture anammox bacteria under mainstream conditions, and two distinct anammox genera (Ca. Kuenenia and Ca. Brocadia) with a relative abundance of 6.31% (C1) and 3.09% (C3), respectively, were identified. Notably, the microbial dynamics revealed that anammox bacteria (AMX), ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB), Chloroflexi bacteria (CFX), and heterotrophic denitrification bacteria (HDB) were the core members in anammox consortia. However, Ca. Kuenenia and Ca. Brocadia occupied different ecological niches in anammox consortia. The dissolved oxygen and microbial structures of the anammox-continuous stirred tank reactor systems were the main factors to affect their niche differentiation. Meanwhile, comammox might exist in the systems and occupy the ecological niche of AOB in nitrogen cycling. The network analysis suggested that Ignavibacterium could be the associated bacteria in Ca. Kuenenia-dominated consortia, while Ca. Nitrotoga was that in the Ca. Brocadia-dominated consortia. Our findings reveal a valuable reference for the observation of distinct anammox genera under mainstream conditions, which provides theoretical guidance for the engineering application of mainstream anammox-based processes.


Assuntos
Compostos de Amônio , Betaproteobacteria , Amônia , Oxidação Anaeróbia da Amônia , Bactérias , Reatores Biológicos/microbiologia , Ecossistema , Nitritos , Nitrogênio , Oxirredução , Oxigênio , Esgotos
9.
Sci Rep ; 12(1): 15249, 2022 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-36085164

RESUMO

There has been no validated tool to assess workplace infection control towards SARS-Cov-2 in non-healthcare industries. In this first year survey during 07/2020-04/2021, 6684 workers were recruited from varied non-healthcare settings of Hong Kong, Nanjing and Wuhan of China and responded standard questionnaires containing information of prevention measures and policies implemented by companies and personal preventive behaviour towards infection control. All participants were randomly stratified into two sub-samples as training and validation sample. Workplace safety index towards SARS-Cov-2 (WSI-SC2) was developed and validated using exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). We identified 14 manifest variables in WSI-SC2, with three sub-indices named "Workplace infection control measures and prevention", "Company occupational safety and health management and commitment" and "Worker's personal preventive behavior and awareness towards infectious control". WSI-SC2 obtained a good internal consistency reliability (Cronbach's alpha coefficients ranged: 0.76-0.91), good composite reliability (composite reliability ranged: 0.70-0.95) and satisfactory fit of the model (GFI = 0.95; SRMR = 0.05; RMSEA = 0.07). We further performed stratified analysis according to cities, and the index remained stable. Workers with higher scores of WSI-SC2 were more likely to uptake COVID-19 test. This multi-city large study developed a novel and validated tool that could horizontally measure the workplace safety towards SARS-Cov-2 in non-healthcare workers.


Assuntos
COVID-19 , SARS-CoV-2 , COVID-19/epidemiologia , COVID-19/prevenção & controle , China/epidemiologia , Cidades , Hong Kong/epidemiologia , Humanos , Reprodutibilidade dos Testes , Local de Trabalho
10.
Chemosphere ; 307(Pt 4): 136151, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36028122

RESUMO

As a by-product of industry, waste iron scraps (WIS) are low-cost and widely available, which was potential for the development of iron-assisted anammox. In this study, the feasibility of adding WIS to enhance the nitrogen removal of the anammox process (also called WIS-assisted anammox) was demonstrated. Results indicated that the WIS-assisted anammox reactors performed a 15-35% higher nitrogen removal efficiency than that of the control. Compared to the sludge from the control, the sludge from the WIS-assisted anammox reactors had a higher iron content (78-113 g kg-1 SS) and a better specific anammox activity (10.8-15.5 mg N g-1 VSS h-1). The enhanced growth of the anammox bacteria (related to Ca. Kuenenia stuttgartiensis with 99% similarity) in the WIS-assisted anammox reactors was also confirmed by high-throughput sequencing and qPCR. Furthermore, the functional genes predicted by PICRUSt2 revealed a higher level of hydroxylamine oxidoreductase (hao)-like proteins expression of the biomass from the WIS-assisted anammox reactors, implying that the hydroxylamine-related anammox pathway was promoted. Additionally, the observation of cytoplasmic nitrate reductase (narG), copper-containing nitrite reductase (nirK), and nitric oxide reductase (norB) suggested that the introduction of WIS might promote the denitrification ability. This was correlated to the lower ΔNO3-/ΔNH4+ ratio observed in these WIS-assisted anammox reactors. Overall, the WIS-assisted anammox offers a sustainable nitrogen removal process for wastewater treatment with waste iron recycling.


Assuntos
Desnitrificação , Esgotos , Oxidação Anaeróbia da Amônia , Reatores Biológicos/microbiologia , Cobre , Hidroxilaminas , Ferro , Nitrito Redutases/metabolismo , Nitrogênio/metabolismo , Oxirredução , Esgotos/microbiologia
11.
Bioresour Technol ; 362: 127857, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36037841

RESUMO

In this study, the microbial diversity of size-fractionated anammox sludge in a well-mixed system and their contribution to nitrogen transformation were investigated. Results showed that small granules (0.2-1.0 mm) contributed to the major part of the nitrogen removal rate (56 %) due to its largest mixed liquor volatile suspended solids (1240 ± 80 mg·L-1). However, large granules (>1.0 mm) possessed the highest relative abundances of Ca. Kuenenia stuttgartiensis and specific anammox activity, representing 49.34 % and 24.45 ± 0.01 mg-N·g-1-mixed liquor volatile suspended solids·h-1, respectively. The microbial diversity decreased as the increase of granular size, resulting in microbial community shifting to a simpler model. Metagenomic analysis showed that fine sludge might be the potential major for NO/N2O production in the mature well-mixed system under inorganic conditions. This study provides guidance for the evaluation of nitrogen contribution by anammox size-fractionated sludge and the inhibition of the potential NO/N2O emission in anammox processes.


Assuntos
Microbiota , Esgotos , Oxidação Anaeróbia da Amônia , Anaerobiose , Reatores Biológicos , Desnitrificação , Nitrogênio , Oxirredução
12.
J Ment Health ; 31(4): 585-596, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35786138

RESUMO

BACKGROUND: Many workers experienced income reduction during the coronavirus disease 2019 (COVID-19) pandemic, which may link to adverse mental health. AIMS: This study aimed to examine the association of current income and reduction in income during COVID-19 with anxiety and depression levels among non-healthcare workers. METHODS: This is a multi-city cross-sectional study. We used standardized questionnaires to collect information. We regrouped the current income and income reduction during COVID-19 according to the tertile and median value of each specific city. Depression, Anxiety and Stress Scales-21 item short version (DASS-21) was used to assess anxiety and depression levels. We performed multinomial logistic regression to examine the association of current and reduced income with anxiety and depression. Path models were developed to outline the potential modification/indirect effect of subsidies from government. RESULTS: Large income reduction and low current income were significantly associated with more anxiety/depression symptoms. Path analysis showed that government subsidies could not significantly alleviate the impact of reduced income on anxiety/depression. CONCLUSION: Our findings showed that large income reduction and low current income were independently associated with anxiety/depression, while these symptoms may not be ameliorated by one-off government funds. This study suggests the need for long-term policies (e.g. developing sustained economic growth policies) to mitigate negative impacts of the COVID-19.


Assuntos
COVID-19 , Pandemias , Ansiedade/epidemiologia , Ansiedade/psicologia , COVID-19/epidemiologia , Estudos Transversais , Depressão/epidemiologia , Depressão/psicologia , Pessoal de Saúde/psicologia , Humanos , SARS-CoV-2
13.
Org Biomol Chem ; 20(27): 5383-5386, 2022 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-35748786

RESUMO

A palladium-catalyzed synthesis of tetrasubstituted allenes from aryl bromides and aryl diazoacetates is developed. This transformation proceeded via an aryl to alkenyl 1,4-palladium migration/carbene insertion/ß-H elimination sequence under mild reaction conditions.


Assuntos
Alcadienos , Paládio , Catálise , Metano/análogos & derivados
14.
Org Lett ; 24(21): 3781-3785, 2022 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-35593884

RESUMO

1,4-Palladium migration has emerged as a reliable method for directed C-H functionalization. In contrast to coupling with carbon nucleophiles, limited examples with heteroatom nucleophiles have been reported. Herein we report a palladium-catalyzed intermolecular C(sp3)-H phosphorylation reaction via 1,4-palladium migration, which is often difficult because of the strong coordination of phosphorus reagents to palladium catalysts. Phosphorylation of C(sp3)-H bonds is accomplished in good reaction yields with excellent regioselectivity. The judicious selection of the phosphine ligand proved to be the key to the success of this cascade process.


Assuntos
Carbono , Paládio , Carbono/química , Catálise , Ligantes , Paládio/química , Fosforilação
15.
Bioresour Technol ; 357: 127344, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35605773

RESUMO

Media-supported biofilm is a powerful strategy for growth and enrichment of slow-growing microorganisms. In this study, a single-stage nitritation-anammox process treating low-strength wastewater was successfully started to investigate the biofilm development on porous polyurethane hydrogel carrier. Suspended biomass migration into the carrier and being entrapment by its internal interconnected micropores dominated the fast initial colonization stage. Both surface-attached growth and embedded growth of microbes occurred during the following accumulation stage. Fluorescence in situ hybridization analysis of mature biofilm indicated that ammonium-oxidizing bacteria located at the outer layers featured a surface-attached growth, while anammox microcolonies housed in the inner layers proliferated as an embedded-like growth. In this way, the growth rate of anammox bacteria (predominated by Candidatus Kuenenia) could be 0.079 d-1. The anammox potential of the biofilm reactor reached 1.65 ± 0.3 kg/m3/d within two months. This study provides novel insights into nitritation-anammox biofilm formation on the porous polyurethane hydrogel carrier.


Assuntos
Compostos de Amônio , Amônia , Oxidação Anaeróbia da Amônia , Bactérias , Biofilmes , Reatores Biológicos/microbiologia , Desnitrificação , Hidrogéis , Hibridização in Situ Fluorescente , Nitrogênio , Oxirredução , Poliuretanos , Porosidade
16.
Chem Commun (Camb) ; 58(46): 6661-6664, 2022 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-35593262

RESUMO

A palladium-catalyzed intermolecular cross-coupling of unreactive C(sp3)-H bonds and azole C(sp2)-H bonds with bromide as a traceless directing group is described. The judicious selection of the bulky and electron-rich phosphine ligand is the key for the success of this cascade process. The protocol features a broad substrate scope, excellent regioselectivity, and good functional group tolerance.


Assuntos
Brometos , Paládio , Azóis , Catálise , Ligantes , Paládio/química
17.
Life (Basel) ; 12(4)2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35455081

RESUMO

Environmental factors affect plant metabolites, different climates, cultivation conditions, and biotic stresses and genotypes strongly affect their chemical composition and contents. Our aim is to examine the environmental and genetic interaction effects on tobacco metabolite composition. UPLC-QTOF MS/MS coupled with multivariate data analyses were applied for the metabolomics analysis of three tobacco cultivars from different planting regions in China. Principal component analysis (PCA) revealed that environmental factors have a greater effect on tobacco metabolism compared to genotypes. Twelve biomarkers were screened by orthogonal partial least squares discrimination analysis (OPLS-DA). Univariate analysis indicated that Malate, conjugated chlorogenic acid, chlorogenic acid, quercetin 3-rutinoside-7-glucoside, and unknown compound 5 were only influenced by environmental factors (independent of genotype). Quinate, neochlorogenic acid, and ouabagenin, taxezopidine K1, taxezopidine K2, and taxezopidine K3 in tobacco were influenced by the interaction of environmental factors and the genotype. Our results suggest that metabolomics based on UPLC-QTOF MS/MS could be used to analyze the ecological functions of biomarker metabolites and understand the mechanisms of plant adaption to the environment.

18.
Int J Biol Macromol ; 209(Pt A): 1457-1464, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35461873

RESUMO

Poly(3-hydroxybutyrate) (PHB), as a kind of bioplastics for sustainable development, can be synthesized by various microorganisms, however, the high cost of its microbial fermentation is a challenge for its large-scale application. In this study, piperazine degrading strain, Paracoccus sp. TOH, was developed as an excellent chassis for open PHB fermentation with piperazine as controlling element. Whole-genome analysis showed that TOH possesses multi-substrate metabolic pathways to synthesize PHB. Next, TOH could achieve a maximum PHB concentration of 2.42 g L-1, representing a yield of 0.36 g-PHB g-1-glycerol when C/N ratio was set as 60:1 with 10 g L-1 glycerol as substrate. Furthermore, TOH could even synthesize 0.39 g-PHB g-1-glycerol under non-sterile conditions when piperazine was fed with a suitable rate of 1 mg L-1 h-1. 16S rRNA gene sequencing analysis showed that microbial contamination could be effectively inhibited through the regulation of piperazine under non-sterile conditions and TOH dominated the microbial community with a relative abundance of 72.3% at the end of the operational period. This study offers an inspired open PHB fermentation system with piperazine as the control switch, which will realize the goal of efficient industrial biotechnology as well as industrial wastewater treatment.


Assuntos
Glicerol , Nitrogênio , Ácido 3-Hidroxibutírico , Fermentação , Glicerol/metabolismo , Hidroxibutiratos/metabolismo , Nitrogênio/metabolismo , Piperazina , Poliésteres/metabolismo , RNA Ribossômico 16S/metabolismo
19.
Chemosphere ; 294: 133831, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35120951

RESUMO

Achieving mainstream nitritation with aerobic granules is attractive based on increasing evidence but generally treating artificial low-ammonium wastewater. Real municipal wastewater is much more complex in composition, the behavior of the nitritation granules would be different when treating real municipal wastewater. Herein, the response of nitritation granules to influent shift from artificial low-ammonium (35-40 mg/L) wastewater to anaerobically pre-treated municipal wastewater (MWWpre-treated) was investigated at low temperatures. Results showed that MWWpre-treated caused the outgrowth of filamentous bacteria on the granule surface and developed into finger-like structures, which in turn resulted in the decrease of the overall granular sludge settleability. Batch-tests and microbial analysis indicated the functional and microbial differentiation between the newly formed fluffy exterior and the original compact granule. The fluffy exterior was dominated by genus Flavobacterium (66.6%) and primarily functioned as COD removal, whereas the nitrifiers (mainly Nitrosomonas) were still located in the compact core and performed nitritation. Moreover, the heterotrophs-dominated fluffy exterior hindered the oxygen transfer towards nitrifiers located in the compact granule and thereby facilitated the stable NOB repression in the granule particularly at low temperatures (<10 °C). Finally, gradual recovery of the granular sludge morphology and settleability occurred after the influent reverted to synthetic low-ammonium wastewater. Overall, this work demonstrated that the feeding of MWWpre-treated only caused morphological changes of the nitritation granules, but its structural and functional stability could be maintained stably.


Assuntos
Compostos de Amônio , Reatores Biológicos/microbiologia , Nitritos , Nitrogênio/análise , Oxirredução , Esgotos/química , Temperatura
20.
Oxid Med Cell Longev ; 2022: 3644318, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35222795

RESUMO

Reduced testosterone level is a common feature of aging in men. Aging, as a risk factor for several neurodegenerative disorders, shows declined mitochondrial function and downregulated mitochondrial biogenesis and mitochondrial dynamics. Mitochondrial biogenesis and mitochondrial dynamics are crucial in maintaining proper mitochondrial function. Supplementation with testosterone is conducive to improving mitochondrial function of males during aging. Nuclear factor erythroid 2-related factor 2 (Nrf2), a regulator of redox homeostasis, is involved in the ameliorative effects of testosterone supplementation upon aging. To explore Nrf2 role in the effects of testosterone supplementation on mitochondrial function during aging, we studied the efficiency of testosterone supplementation in improving mitochondrial function of Nrf2 knockout- (KO-) aged male mice by analyzing the changes of mitochondrial biogenesis and mitochondrial dynamics. It was found that wild-type- (WT-) aged male mice showed low mitochondrial function and expression levels of PGC-1α, NRF-1\NRF-2, and TFAM regulating mitochondrial biogenesis, as well as Drp1, Mfn1, and OPA1 controlling mitochondrial dynamics in the substantia nigra (SN). Nrf2 KO aggravated the defects above in SN of aged male mice. Testosterone supplementation to WT-aged male mice significantly ameliorated mitochondrial function and upregulated mitochondrial biogenesis and mitochondrial dynamics, which were not shown in Nrf2 KO-aged male mice due to Nrf2 deficiency. Testosterone deficiency by gonadectomy (GDX) decreased mitochondrial function, downregulated mitochondrial biogenesis, and altered mitochondrial dynamics balance in young male mice. Supplementation with testosterone to Nrf2 KO-GDX mice only ameliorated the alterations above but did not reverse them to sham level. Nrf2 deficiency attenuated testosterone efficiency in ameliorating mitochondrial function in the SN of aged male mice through mitochondrial biogenesis and mitochondrial dynamics to some extent. Activation of Nrf2 might contribute to testosterone-upregulating mitochondrial biogenesis and mitochondrial dynamics in the SN during aging to produce efficient mitochondria for ATP production.


Assuntos
Envelhecimento/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Fator 2 Relacionado a NF-E2/deficiência , Substância Negra/efeitos dos fármacos , Testosterona/farmacologia , Envelhecimento/metabolismo , Animais , Suplementos Nutricionais , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos ICR , Camundongos Knockout , Mitocôndrias/metabolismo , Dinâmica Mitocondrial/efeitos dos fármacos , Biogênese de Organelas , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Substância Negra/metabolismo , Testosterona/administração & dosagem , Testosterona/deficiência , Caminhada
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