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Eukaryotic translation initiation factors have long been recognized for their critical roles in governing the translation of coding RNAs into peptides/proteins. However, whether they harbor functional activities at the post-translational level remains poorly understood. Here, we demonstrate that eIF3f1 (eukaryotic translation initiation factor 3 subunit f1), which encodes an archetypal deubiquitinase, is essential for the antimicrobial innate immune defense of Drosophila melanogaster. Our in vitro and in vivo evidence indicate that the immunological function of eIF3f1 is dependent on the N-terminal JAMM (JAB1/MPN/Mov34 metalloenzymes) domain. Mechanistically, eIF3f1 physically associates with dTak1 (Drosophila TGF-beta activating kinase 1), a key regulator of the IMD (immune deficiency) signaling pathway, and mediates the turnover of dTak1 by specifically restricting its K48-linked ubiquitination. Collectively, these results provide compelling insight into a noncanonical molecular function of a translation initiation factor that controls the post-translational modification of a target protein.
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Proteínas de Drosophila , Drosophila , Animais , Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Proteínas de Drosophila/metabolismo , Imunidade Inata , Fatores de Iniciação de Peptídeos , Transdução de SinaisRESUMO
As the negative repercussions of environmental devastation, such as air quality decline and air pollution, become more apparent, environmental consciousness is growing across the world, forcing nations to take steps to mitigate the damage. China pledged to achieve air quality improvement goal to combat global environment issue, yet the spatial-temporal differentiation and its driving factors of environment-meteorology-economic index for air quality are not fully analysed. To promote regional collaborative control of air pollution and achieve sustainable urban development, spatial and temporal different and its driving factors of air quality in Shandong Province during 2013-2020. Results revealed that concentrations of sulfur dioxide (SO2), nitrogen dioxide (NO2), particulate matter 2.5 (PM2.5), particulate matter 10 (PM10), and carbon monoxide (CO-95per) exhibited decreasing trend (SO2 concentrations decreasing 84â¯% and CO-95per concentrations decreasing 90â¯%). Air quality was improved from inland areas to coastal areas. Pollutant indicators of SO2, NO2, PM10, PM2.5, and CO-95per demonstrated significant positive correlation (P < 0.05). Air temperature and precipitation are significantly negatively correlated with concentrations of SO2, NO2, PM10, PM2.5, and CO-95per but significantly positively correlated with ozone (O3-8â¯h). SO2, NO2, PM2.5, PM10, CO-95per, and proportion of days with heavy pollution are strongly positively correlated with proportion of secondary industry but strongly negatively correlated with proportion of tertiary industry and volume of household waste. Except for O3-8â¯h, pollutant index of Provincial Capital Economic Circle (PCEC) and Southern Shandong Economic Circle (SSEC) has significant negative correlation (P < 0.05) with regional gross domestic product and investment in environmental protection; however, investment in environmental protection of Eastern Shandong Economic Circle (ESEC) has no significant correlation with air pollution index. There was significant negative correlation between vegetable sowing area and SSEC pollutant index. The relationship between pollution emission and investment in environmental protection has shifted from high pollution-low investment to low pollution-low investment in PCEC, ESEC and SSEC, and the inflection point was in 2020 for PCEC, 2019 for ESEC, and 2020 for SSEC. Those results provide empirical evidence and theoretical support for the improvement of regional air quality, aiming to achieve high-quality development. According to these findings, it has been found that meteorological elements, pollutant emission, socio-economic factors and agricultural data affect air quality. Those results could provide meaningful and significant supporting for synergistic regulation of diverse pollutants.
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Insufficient carbon source has become the main limiting factor for efficient nitrogen removal in wastewater treatment. In this study, an intermittently-aerated activated sludge system with iron-chitosan (Fe-CS) beads addition was proposed for nitrogen removal from low C/N wastewater. By adding Fe-CS beads, partial nitrification-denitrification (PND) process and significant enrichment of Paracoccus (with ability of iron reduction/ammonium oxidation/aerobic denitrification) were observed in the reactor. The accumulation rate of NO2--N reached 81.9 %, and the total nitrogen removal efficiency was improved to 93.9 % by shortening the aeration time. The higher activity of ammonium oxidizing bacteria and inhibited activity of nitrite-oxidizing bacteria in Fe-CS assisted system mediated the occurrence of PND. In contrast, the traditional nitrification and denitrification process occurred in the control group. The high-throughput sequencing analysis and metagenomic results confirmed that the addition of Fe-CS induced 77.8 % and 54.9 % enrichment of Paracoccus in sludge and Fe-CS beads, respectively, while almost no enrichment was observed in control group. Furthermore, with the addition of Fe-CS beads, the expression of genes related to outer membrane porin, cytochrome c, and TCA was strengthened, thereby enhancing the electron transport of Fe(â ¡) (electron donor) and Fe(â ¢) (electron acceptor) with pollutants in the periplasm. This study provides new insights into the direct enrichment of iron-reducing bacteria and its PND performance induced by the Fe-CS bead addition. It therefore offers an appealing strategy for low C/N wastewater treatment.
Assuntos
Compostos de Amônio , Quitosana , Paracoccus , Nitrificação , Esgotos , Desnitrificação , Quitosana/metabolismo , Ferro , Paracoccus/metabolismo , Reatores Biológicos/microbiologia , Bactérias/metabolismo , Compostos de Amônio/metabolismo , Oxirredução , Nitrogênio/metabolismoRESUMO
Aspirin, also known as acetylsalicylic acid, is widely consumed as a pain reliever and an anti-inflammatory as well as anti-platelet agent. Recently, our studies using the animal model of Drosophila demonstrated that the dietary supplementation of aspirin renovates age-onset intestinal dysfunction and delays organismal aging. Nevertheless, it remains probable that aspirin plays functional roles in other biological activities, for instance antiviral defense reactions. Intriguingly, we observed that the replications of several types of viruses were drastically antagonized in Drosophila macrophage-like S2 cells with the addition of aspirin. Further in vivo experimental approaches illustrate that adult flies consuming aspirin harbor higher resistances to viral infections with respect to flies without aspirin treatment. Mechanistically, aspirin positively contributes to the Drosophila antiviral defense largely through mediating the STING (stimulator of interferon genes) but not the IMD (immune deficiency) signaling pathway. Collectively, our studies uncover a novel biological function of aspirin in modulating Drosophila antiviral immunity and provide theoretical bases for exploring new antiviral treatments in clinical trials.
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Drosophila , Viroses , Animais , Aspirina/farmacologia , Aspirina/metabolismo , Imunidade Inata , Antivirais/metabolismo , Suplementos Nutricionais , Drosophila melanogaster/metabolismoRESUMO
BACKGROUND: Sodium dehydroacetate (DHA-S) is a common food additive, which can combine with serum proteins in the plasma, but the interaction mechanism between DHA-S and human serum albumin (HSA) is unclear. In this study, multiple spectroscopy techniques, isothermal titration calorimetry (ITC), molecular docking and esterase activity test were employed to investigate the interaction mechanism of DHA-S and HSA. RESULTS: A DHA-S-HSA complex was formed and the structure of HSA were altered by DHA-S. Since DHA-S changed the tight structure of the hydrophobic subdomain IIA where tryptophan (Trp) was placed, the hydrophobicity of the microenvironment of HSA was enhanced. With the addition of DHA-S, the skeleton structure of HSA became loose and the solvent shell on the HSA surface was destroyed. DHA-S altered the secondary structure of HSA, resulting in the decreased α-helix and increased ß-sheet contents. The interaction was exothermic and spontaneous driven by van der Waals and hydrogen bonding. DHA-S inhibited the esterase activity of HSA. Molecular docking demonstrated that the binding site of DHA-S on HSA located at the cavity of subdomains IIA and IIIA, but the amino acids related to esterase activity of HSA were not in the binding pocket, indicating that the mechanism by which DHA-S inhibited HSA esterase activity was the change in protein structure. CONCLUSION: This study illustrated that DHA-S interacted with HSA and the structure and function of HSA were affected by DHA-S. This research could help to understand the toxicity of DHA-S and provide basic data for safe use of food additives. © 2021 Society of Chemical Industry.
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Esterases , Albumina Sérica Humana , Sítios de Ligação , Dicroísmo Circular , Esterases/metabolismo , Humanos , Ligação de Hidrogênio , Simulação de Acoplamento Molecular , Ligação Proteica , Pironas , Albumina Sérica Humana/química , Albumina Sérica Humana/metabolismo , Espectrometria de Fluorescência , TermodinâmicaRESUMO
During sediment remediation, adsorbent addition is an effective technology for the removal of contaminants but the cost is often high. In this study, a low-cost adsorbent, ceramsite, made from contaminated riverbed sediment was synthesized. The Fe-modified ceramsite (FMC) was used as adsorbent to remove arsenate from aqueous solutions and reduce the inorganic arsenic release from contaminated sediments. Kinetic studies showed that chemisorption mainly governed the adsorption process while batch studies yielded the theoretical adsorption capacity for arsenate of 10.63 mg/g at pH = 7 condition. Co-existing anions and pH have no significant impact on the adsorption process. In the regeneration studies, 91, 86, and 80% of the adsorption capacity were recovered in 3 cycles. In-situ remediation trials revealed that the addition of the adsorbent to sediment surface significantly reduced the release of inorganic arsenic into aqueous system, with a reduction efficiency of 86%. Furthermore, the species of the arsenic in the surface layer was significantly inactivated from an active state to a stable state. These findings highlight the application of the FMC as a facile and cost-effective adsorbent for containment of arsenic in solutions and sediments, demonstrating that they are highly applicable for practical cases.
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Arsênio , Poluentes Químicos da Água , Purificação da Água , Adsorção , Misturas Complexas , Concentração de Íons de Hidrogênio , CinéticaRESUMO
This study proposed a multi-criteria evaluation system for arable land resources by combining the soil integrated fertility index (IFI) with a soil cleanliness index (based on heavy metals and metalloid content). A total of 16 typical arable land units in Chongming District, China, were evaluated using the proposed evaluation system based on 104 collected soil samples in 16 towns. The comprehensive soil evaluation scores of arable lands in 16 towns were in the range of 90.7 to 99.2 with a mean of 96.2, indicating that the arable land in all 16 towns was at the level of excellent (≥ 90.0). Lower cleanliness indices had a significant impact on the final evaluation score. In comparison with single-index evaluation systems (i.e., the IFI or soil cleanliness index), the proposed multi-criteria system better reflects the quality of the soil. In the practice of arable land requisition and subsidy policy, the proposed multi-criteria evaluation system not only encourages farmers to preserve arable lands during farming but also helps agricultural authorities make effective and reliable management decisions.
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Agricultura , Monitoramento Ambiental , China , Metais Pesados/análise , SoloRESUMO
BACKGROUND Although many attempts have been made to advance the treatment of complex anal fistula, it continues to be a difficult surgical problem. This study aimed to describe the novel technique of video-assisted anal fistula treatment (VAAFT) and our preliminary experiences using VAAFT with patients with complex anal fistula. MATERIAL AND METHODS From May 2015 to May 2016, 52 patients with complex anal fistula were treated with VAAFT at Yangpu Hospital of Tongji University School of Medicine, and the clinical data of these patients were reviewed. RESULTS VAAFT was performed successfully in all 52 patients. The median operation time was 55 minutes. Internal openings were identified in all cases. 50 cases were closed with sutures, and 2 were closed with staplers. Complications included perianal sepsis in 3 cases and bleeding in another 3 cases. Complete healing without recurrence was achieved in 44 patients (84.6%) after 9 months of follow-up. No fecal incontinence was observed. Furthermore, a significant improvement in Gastrointestinal Quality of Life Index (GIQLI) score was observed from preoperative baseline (mean, 85.5) to 3-month follow-up (mean, 105.4; p<0.001), and this increase was maintained at 9-months follow-up (mean, 109.6; p<0.001). CONCLUSIONS VAAFT is a safe and minimally invasive technique for treating complex anal fistula with preservation of anal sphincter function.
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Fístula Retal/cirurgia , Cirurgia Vídeoassistida/métodos , Adulto , Idoso , Canal Anal/cirurgia , China , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Duração da Cirurgia , Qualidade de Vida , Fístula Retal/terapia , Recidiva , Resultado do Tratamento , CicatrizaçãoRESUMO
BACKGROUND Systemic inflammatory response and nutritional status are important to the prognosis of patients with colorectal cancer (CRC). This study aimed to investigate the prognostic value of the combination of preoperative hemoglobin, lymphocyte, albumin, and neutrophil (HLAN) in patients with locally advanced CRC (LACRC). MATERIAL AND METHODS We performed a retrospective analysis in 536 LACRC patients undergoing radical surgery. The value of HLAN was defined as follow: HLAN=Hemoglobin (g/L)×Lymphocyte (/L)×Albumin (g/L)/Neutrophil (/L)/100. The X-tile program was used to determine the optimal cut-point of HLAN, and the prognostic value of HLAN for overall survival (OS) was evaluated with the Cox proportional hazard model. RESULTS The cut-point of HLAN was set at 19.5. Compared with the high-HLAN group, the low-HLAN group had a 1.50-fold (95% confidence interval 1.09-2.05) increased risk of death and a significantly lower OS rate (P<0.001). Furthermore, the risk stratification model based on HLAN (AUC=0.72) displayed better accuracy in OS prediction than the TNM system (AUC=0.61). CONCLUSIONS HLAN is a valuable prognostic marker for patients with LACRC.
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Biomarcadores Tumorais/sangue , Neoplasias Colorretais/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Hemoglobinas/metabolismo , Humanos , Estimativa de Kaplan-Meier , Linfócitos/patologia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias/métodos , Neutrófilos/patologia , Prognóstico , Estudos Retrospectivos , Albumina Sérica/metabolismo , Taxa de SobrevidaRESUMO
Polycyclic aromatic hydrocarbon (PAH) concentrations and fluxes were measured monthly in situ from rain events in an urban forest in the megapolitan city Guangzhou, China, to investigate impacts of forest canopy and soils on PAHs. Mean Σ9-PAH concentrations were 107.5, 101.6, 106.3, 107.1 and 42.4 ng L(-1) in precipitation, throughfall, seepage water at the 30 and 60 cm soil depth, and runoff, respectively, indicating a great decrease in the form of runoff. Meanwhile, annual fluxes of total PAHs decreased from precipitation (205.9 µg m(-2) year(-1)), to throughfall (156.3 µg m(-2) year(-1)), and to seepage water (65.3 µg m(-2) year(-1) at 30-cm soil depth and 7.5 µg m(-2) year(-1) at 60-cm soil depth), but increased in runoff (34.1 µg m(-2) year(-1)). When compared to precipitation, PAH fluxes decreased by 83.4% in runoff, with 29% contributed by forest canopy and 71% by soils. Soil biodegradation explained 18.2% of PAH reduction by the surface soil layer and 34.6% by the middle soil layer.
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Poluentes Atmosféricos/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Chuva/química , Poluentes Atmosféricos/metabolismo , Biodegradação Ambiental , China , Cidades , Florestas , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Microbiologia do SoloRESUMO
In this study, an anaerobic/intermittently-aerated moving bed biofilm reactor (AnIA-MBBR) was proposed to realize simultaneous nitrification and endogenous denitrifying phosphorus removal (SNEDPR) in treating low carbon-to-nitrogen (C/N) ratio wastewater. The effect of different intermittent aeration modes (short and long aeration) on nutrients' removal was investigated. With the C/N ratio around 3, the removal efficiencies of total nitrogen and phosphorus were 90% and 74%, 88% and 59%, respectively, for short aeration and long aeration. The different aeration time also altered the nutrients' degradation pathway, biofilm characteristics, microbial community, and functional metabolic pathways. The results confirmed the occurrence of aerobic denitrifiers, anoxic denitrifiers, phosphorus accumulating organisms, glycogen accumulating organisms in AnIA-MBBR systems and their synergistic performance induced the SNEDPR. These results indicated that the application of AnIA in MBBR systems was an effective strategy to achieve SNEDPR, providing better simultaneous removal performance of nitrogen and phosphorus from low C/N ratio wastewater.
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Nitrificação , Purificação da Água , Águas Residuárias , Desnitrificação , Eliminação de Resíduos Líquidos/métodos , Esgotos , Fósforo/metabolismo , Nitrogênio/metabolismo , Carbono/metabolismo , Biofilmes , Anaerobiose , Reatores BiológicosRESUMO
Pharmaceuticals, which are closely linked to human activities, have attracted global attention. This study investigated the occurrence characteristics of 20 pharmaceuticals in surface water of the Yangtze Estuary and adjacent sea. A total of 14 targeted pharmaceuticals were detected in both spring and summer sampling campaigns. The mean concentrations of sulfonamides and non-sulfonamides were 36.60 ± 19.43 ng·L-1 and 50.02 ± 41.07 ng·L-1, respectively. As for non-antibiotics, their concentrations were in the range of 24.34 ± 916.8 ng·L-1 with caffeine accounting for 6.17 ~ 86.70% (average percentage of 42.22%). Meanwhile, spatial distribution patterns showed similarities between antibiotics and non-antibiotics, with high levels occurring near the upper estuary, aquaculture areas, wastewater treatment plants, and the maximum turbidity zone. This phenomenon could be related to the sources of pharmaceuticals and the physicochemical properties of water bodies. Obviously, the first three areas are highly impacted by human activities or serve as important sources of terrestrial contaminants entering the East China Sea. The last area retains high amounts of suspended particles which may exert strong trapping effects on hydrophobic chemicals. Principal component analysis revealed the presence of three potential sources for pharmaceuticals in the Yangtze Estuary, with a relatively high percentage originating from incompletely treated municipal sewage. As for the temporal trend, pharmaceutical contamination was found to be higher in spring compared to summer, potentially due to variations in pharmaceutical consumption patterns, local rainfalls, and water temperatures. These findings provide fundamental data support for implementing appropriate local management strategies for pharmaceutical usages.
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Conventional thyroid-disrupting chemicals (TDCs) such as polybrominated diphenyl ethers, polychlorinated biphenyls, and bisphenols perturb animal's thyroid endocrine system by mimicking the action of endogenous thyroid hormones (THs), since they share a similar backbone structure of coupled benzene rings with THs. 1-methyl-3-octylimidazolium bromide ([C8mim]Br), a commonly used ionic liquid (IL), has no structural similarity to THs. Whether it interferes with thyroid function and how its mode of action differs from conventional TDCs is largely unknown. Herein, zebrafish embryo-larvae experiments (in vivo), GH3 cell line studies (in vitro), and molecular simulation analyses (in silico) were carried out to explore the effect of [C8mim]Br on thyroid homeostasis and its underlying mechanism. Molecular docking results suggested that [C8mim]+ likely bound to retinoid X receptors (RXRs), which may compromise the formation of TH receptor/RXR heterodimers. This then perturbed the negative regulation of thyroid-stimulating hormone ß (tshß) transcription by T3 in GH3 cell line. The resulting enhancement of tshß expression further caused hyperthyroidism and developmental toxicity in larval zebrafish. These findings provided a crucial aspect of the ecological risks of ILs, and presented a new insight into the thyroid-disrupting mechanisms for emerging pollutants that do not have structural similarity to THs.
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Glândula Tireoide , Poluentes Químicos da Água , Animais , Peixe-Zebra/metabolismo , Simulação de Acoplamento Molecular , Poluentes Químicos da Água/toxicidade , Sistema Endócrino , Hormônios Tireóideos/metabolismo , LarvaRESUMO
Microplastics (MPs) undergo physical, chemical, and biological aging in the environment, leading to changes in their physicochemical properties, affecting migration characteristics and toxicity. Oxidative stress effects induced by MPs in vivo have been extensively studied, but the toxicity difference between virgin and aged MPs and the interactions between antioxidant enzymes and MPs in vitro have not been reported yet. This study investigated the structural and functional changes of catalase (CAT) induced by virgin and aged PVC-MPs. It was shown that light irradiation aged the PVC-MPs, and the aging mechanism was photooxidation, resulting in a rough surface and appearing holes and pits. Because of the changes in physicochemical properties, aged MPs had more binding sites than virgin MPs. Fluorescence and synchronous fluorescence spectra results suggested that MPs quenched the endogenous fluorescence of CAT and interacted with tryptophane and tyrosine residues. The virgin MPs had no significant effect on the skeleton of CAT, while the skeleton and the polypeptide chains of CAT became loosened and unfolded after binding with the aged MPs. Moreover, the interactions of CAT with virgin/aged MPs increased the α-helix and decreased the ß-sheet contents, destroyed the solvent shell, and resulted in a dispersion of CAT. Due to the large size, MPs cannot enter the interior of CAT and have no effects on the heme groups and activity of CAT. The interaction mechanism between MPs and CAT may be that MPs adsorb CAT to form the protein corona, and aged MPs had more binding sites. This study is the first comprehensive investigation of the effect of aging on the interaction between MPs and biomacromolecules and highlights the potential negative effects of MPs on antioxidant enzymes.
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Microplásticos , Poluentes Químicos da Água , Microplásticos/toxicidade , Plásticos , Catalase , Antioxidantes , Estresse Oxidativo , Poluentes Químicos da Água/toxicidade , Poluentes Químicos da Água/análiseRESUMO
Microplastics are harmful pollutants that widely exist worldwide and pose a severe threat to all types of organisms. The effects of polystyrene microplastics (PS-MPs) on organisms have been extensively studied, but the interaction mechanism between PS-MPs and superoxide dismutase (SOD) at the molecular level has not been reported yet. Therefore, based on multiple spectroscopic methods and enzyme activity measurements, the molecular mechanism of the interaction between PS-MPs and SOD was investigated. The multispectral results showed that the protein skeleton and secondary structure of SOD were altered by PS-MPs, resulting in decreased α-helix and ß-sheet content. After PS-MPs exposure, fluorescence sensitization occurred, and micelles were formed, along with the enhanced hydrophobicity of aromatic amino acids in SOD. Moreover, the resonance light scattering (RLS) spectra result suggested that the PS-MPs and SOD combined to form a larger complex. Eventually, the activity of SOD was increased due to these structural changes, and the concentration of PS-MPs is positively correlated with SOD activity. This study can provide experimental support for studying the toxicological effects of PS-MPs.
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Poliestirenos , Poluentes Químicos da Água , Poliestirenos/metabolismo , Microplásticos , Plásticos , Superóxido Dismutase , Poluentes Químicos da Água/metabolismo , Análise EspectralRESUMO
Nanoplastics are emerging pollutants that pose a potential threat to the environment and organisms and are widely distributed in environmental samples and food chains. The accumulation of polystyrene nanoplastics (PS-NPs) in an organism can cause oxidative stress. Currently, toxicity studies of PS-NPs mainly focus on the individual and cellular levels, whereas few studies have been conducted on the molecular mechanisms of the interaction between PS-NPs and catalase (CAT). Based on this, CAT was chosen as the target receptor for molecular toxicity research to reveal the interaction mechanism at the molecular level between PS-NPs and CAT by using various spectroscopic means and enzyme activity detection methods. The results indicated that PS-NPs destroyed the secondary structure of CAT, causing its protein skeleton to loosen and unfold, increasing the content of α-helices, decreasing the content of ß-sheets, and exposing the position of the heme group. After exposure to PS-NPs, the internal fluorophore of CAT underwent fluorescence sensitization, resulting in a micelle-like structure, which enhanced the hydrophobicity of aromatic amino acids but did not change their polarity. In addition, the aggregation state of CAT was altered upon binding to PS-NPs, and the volume was further increased. Finally, these structural changes led to a gradual decrease in CAT activity. This study presents a comprehensive assessment of the toxicity of PS-NPs at the molecular level, which can provide more experimental support for the study of the biotoxicological efficacy of PS-NPs.
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Nanopartículas , Poluentes Químicos da Água , Poliestirenos/toxicidade , Poliestirenos/química , Microplásticos , Catalase , Estresse Oxidativo , Nanopartículas/química , Poluentes Químicos da Água/toxicidadeRESUMO
Decentralized wastewater pollution in rural areas has become a serious problem for the rural environment. In this study, a novel rotating self-aerated biofilm reactor was developed for decentralized wastewater treatment without any aeration equipment. After the long-term operation of 110 days, the removal efficiency reached to 96.06 % (COD), 98.06 % (NH4+-N), and 62.58 % (TN) in the last phase. Under high dissolved oxygen level, the simultaneous nitrification-denitrification (SND) maintained at a stable ratio of 62.53 % and the denitrification rates reached over 28.37 mg/L/h. With the organic loading rate increased, key nitrogen functional bacterial communities such as anoxic denitrifiers (Thiothrix, Flavobacterium, Pseudoxanthomonas, Aquimonas and Azoarcus) and aerobic denitrifiers (Hydrogenophaga, Zoogloea and Terrimonas) increased obviously. Overall, microbial analysis and nitrogen metabolism pathway indicated that an integration of SND process was achieved in this single reactor by the combined action of nitrification, denitrification and comammox without any aeration equipment.
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Desnitrificação , Nitrificação , Reatores Biológicos/microbiologia , Biofilmes , Nitrogênio/metabolismo , Eliminação de Resíduos LíquidosRESUMO
To achieve energy-efficient treatment of the rural wastewater with satisfying performance, a novel immersed rotating self-aerated biofilm reactor (iRSABR) was proposed in this study. The iRSABR system showed better biofilm renewal performance and higher microbial activity. The effect of different regulation strategies on the iRSABR system was investigated in this study. The 70% immersion ratio and 4 r/min rotation speed (stage III) exhibited the best performance, with a total nitrogen removal efficiency of 86% and a simultaneous nitrification-denitrification (SND) rate of 76%, along with the highest electron transport system activity. The nitrogen removal pathway revealed that the SND was achieved through autotrophic/heterotrophic nitrification and aerobic/anoxic denitrification. The regulation strategy in the iRSABR system established a synergistic microbial community with main functional bacteria of nitrification (Nitrosomonas), anoxic denitrification (Flavobacterium, Pseudoxanthomonas), and aerobic denitrification (Thauera). This study highlighted the feasibility and adaptability of the iRSABR system toward energy-efficient rural wastewater treatment.
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Desnitrificação , Nitrogênio , Nitrogênio/metabolismo , Reatores Biológicos , Nitrificação , BiofilmesRESUMO
Microplastics (MPs) can affect phytoplankton and its photosynthetic performance in many but often in negative ways. Phytoplankton is an important source of dissolved organic matter (DOM) in aquatic ecosystems, but the impact of MPs on the algal production of DOM is poorly known. We investigated the impacts of polyvinyl chloride MPs on the growth and DOM production by Chlamydomonas reinhardtii microalgae in a 28-day-long experiment. During the exponential growth phase of C. reinhardtii, MPs slightly affected algal growth and DOM production. At the end of experiment, MPs decreased the biomass of C. reinhardtii by 43 % in the treatment with MPs exposed to simulated solar radiation prior the experiment (light-aged) and more than in the treatment with virgin MPs. The light-aged MPs decreased algal DOM production by 38 % and modified the chemical composition of DOM. According to spectroscopic analyses, the light-aged MPs increased aromaticity, average molecular weight and fluorescence of DOM produced by C. reinhardtii. The elevated fluorescence was associated with humic-like components identified by a 5-component parallel factor analysis (PARAFAC) from the excitation-emission matrices. We conclude that although MPs can leach DOM to aquatic ecosystems, they potentially modify the aquatic DOM more by interfering with the algal production of DOM and changing the composition of produced DOM.
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Microalgas , Plásticos , Microplásticos , Matéria Orgânica Dissolvida , Ecossistema , Fitoplâncton , Espectrometria de Fluorescência/métodos , Substâncias Húmicas/análise , Análise FatorialRESUMO
Reclaimed water from municipal wastewater has great potential in mitigating the water resource crisis, while the inevitable residue of organic micropollutants (OMPs) challenges the safety of reclaimed water reuse. Limited information was available regarding the overall adverse effects of mixed OMPs in reclaimed water, especially the endocrine-disrupting effects on living organisms. Herein, chemical monitoring in two municipal wastewater treatment plants showed that 31 of 32 candidate OMPs including polycyclic aromatic hydrocarbons (PAHs), phenols, pharmaceuticals and personal care products (PPCPs) were detected in reclaimed water, with a concentration ranging from ng/L to µg/L. Then, based on the risk quotient value, phenol, bisphenol A, tetracycline, and carbamazepine were ranked as high ecological risks. Most PAHs and PPCPs were quantified as medium and low risks, respectively. More importantly, using aquatic vertebrate zebrafish as an in vivo model, the endocrine-disrupting potentials of OMP mixtures were comprehensively characterized. We found that a realistic exposure to reclaimed water induced estrogen-like endocrine disruption and hyperthyroidism in zebrafish, abnormal expression of genes along the hypothalamus-pituitary-thyroid (-gonad) axes, reproductive impairment, and transgenerational toxicity. Based on the chemical analyses, risk quotient calculations, and biotoxicity characterization, this study contributed to understanding the ecological risks of reclaimed water and developing the control standards for OMPs. In addition, application of the zebrafish model in this study also highlighted the significance of in vivo biotoxicity test in water quality evaluation.