Role of comammox bacteria in granular bioreactor for nitrogen removal via partial nitritation/anammox.

In this study, two bioprocess models were first constructed with the newly-discovered comammox process described as one-step and two-step nitrification and evaluated against relevant experimental data. The validated models were then applied to reveal the potential effect of comammox bacteria on the granular bioreactor particularly suitable for undertaking partial nitritation/anammox (PN/A) under different operating conditions of bulk dissolved oxygen (DO) and influent NH4+. The results showed although comammox bacteria-based PN/A could achieve > 80.0 % total nitrogen (TN) removal over a relatively wider range of bulk DO and influent NH4+ (i.e., 0.25-0.40 g-O2/m3 and 470-870 g-N/m3, respectively) without significant nitrous oxide (N2O) production (< 0.1 %), the bulk DO should be finely controlled based on the influent NH4+ to avoid the undesired full nitrification by comammox bacteria. Comparatively, conventional ammonium-oxidizing bacteria (AOB)-based PN/A not only required higher bulk DO to achieve > 80.0 % TN removal but also suffered from 1.7 %∼2.8 % N2O production.

A Novel Sustainable and Self-Sufficient Biotechnological Strategy for Directly Transforming Sewage Sludge into High-Value Liquid Biochemicals.

Sewage sludge, as a carbon-rich byproduct of wastewater treatment, holds significant untapped potential as a renewable resource. Upcycling this troublesome waste stream represents great promise in addressing global escalating energy demands through its wide practice of biochemical recovery concurrently. Here, we propose a biotechnological concept to gain value-added liquid bioproducts from sewage sludge in a self-sufficient manner by directly transforming sludge into medium-chain fatty acids (MCFAs). Our findings suggest that yeast, a cheap and readily available commercial powder, would involve ethanol-type fermentation in chain elongation to achieve abundant MCFA production from sewage sludge using electron donors (i.e., ethanol) and acceptors (i.e., short-chain fatty acids) produced in situ. The enhanced abundance and transcriptional activity of genes related to key enzymes, such as butyryl-CoA dehydrogenase and alcohol dehydrogenase, affirm the robust capacity for the self-sustained production of MCFAs. This is indicative of an effective metabolic network established between yeast and anaerobic microorganisms within this innovative sludge fermentation framework. Furthermore, life cycle assessment and techno-economic analysis evidence the sustainability and economic competitiveness of this biotechnological strategy. Overall, this work provides insights into sewage sludge upgrading independent of additional carbon input, which can be applied in existing anaerobic sludge fermentation infrastructure as well as to develop new applications in a diverse range of industries.

Mixotrophic denitrification of waste activated sludge fermentation liquid as an alternative carbon source for nitrogen removal: Reducing N2O emissions and costs.

Heterotrophic-sulfur autotrophic denitrification (HAD) has been proposed to be a prospective nitrogen removal process. In this work, the potential of fermentation liquid (FL) from waste-activated sludge (WAS) as the electron donor for denitrification in the HAD system was explored and compared with other conventional carbon sources. Results showed that when FL was used as a carbon source, over 99% of NO3--N was removed and its removal rate exceeded 14.00 mg N/g MLSS/h, which was significantly higher than that of methanol and propionic acid. The produced sulfate was below the limit value and the emission of N2O was low (1.38% of the NO3--N). Microbial community analysis showed that autotrophic denitrifiers were predominated in the HAD system, in which Thiobacillus (16.4%) was the dominant genus. The economic analysis showed the cost of the FL was 0.062 €/m3, which was 30% lower than that in the group dosed with methanol. Our results demonstrated the FL was a promising carbon source for the HAD system, which could reduce carbon emission and cost, and offer a creative approach for waste-activated sludge resource reuse.

Removal and assessment of cadmium contamination based on the toxic responds of a soil ciliate Colpoda sp.

Bioremediation of cadmium (Cd) pollution, a recognized low-carbon green environmental protection technology, is significantly enhanced by the discovery of Cd-tolerant microorganisms and their underlying tolerance mechanisms. This study presents Colpoda sp., a soil ciliate with widespread distribution, as a novel bioindicator and bioremediator for Cd contamination. With a 24 h-LC50 of 5.39 mg l-1 and an IC50 of 24.85 µg l-1 in Cd-contaminated water, Colpoda sp. achieves a maximum bioaccumulation factor (BAF) of 3.58 and a Cd removal rate of 32.98 ± 0.74 % within 96 h. The toxic responses of Colpoda sp. to Cd stress were assessed through cytological observation with transmission electron microscopy (TEM), oxidative stress kinase activity, and analysis of Cd-metallothionein (Cd-MTs) and the cd-mt gene via qRT-PCR. The integrated biomarker response index version 2 (IBRv2) and structural equation models (SEM) were utilized to analyze key factors and mechanisms, revealing that the up-regulation of Cd-MTs and cd-mt expression, rather than the oxidative stress system, is the primary determinant of Cd accumulation and tolerance in Colpoda sp. The ciliate's ability to maintain growth under 24.85 µg l-1 Cd stress and its capacity to absorb and accumulate Cd particles from water into cells are pivotal for bioremediation. A new mathematical formula and regression equations based on Colpoda sp.'s response parameters have been established to evaluate environmental Cd removal levels and design remediation schemes for contaminated sites. These findings provide a novel bioremediation and monitoring pathway for Cd remobilization and accumulation in soil and water, potentially revolutionizing the governance of Cd pollution.

Effects of Psychological Stress on Multiple Sclerosis via HPA Axis-mediated Modulation of Natural Killer T Cell Activity.

The involvement of psychological stress and Natural Killer T (NKT) cells in the pathophysiology of multiple sclerosis has been identified in the progression of this disease. Psychological stress can impact disease occurrence, relapse, and severity through its effects on the Hypothalamic- Pituitary-Adrenal (HPA) axis and immune responses. NKT cells are believed to play a pivotal role in the pathogenesis of multiple sclerosis, with recent evidence suggesting their distinct functional alterations following activation of the HPA axis under conditions of psychological stress. This review summarizes the associations between psychological stress, NKT cells, and multiple sclerosis while discussing the potential mechanism for how NKT cells mediate the effects of psychological stress on this disease.

Synergistic Integration of Anammox and Endogenous Denitrification Processes for the Simultaneous Carbon, Nitrogen, and Phosphorus Removal.

The feasibility of a synergistic endogenous partial denitrification-phosphorus removal coupled anammox (SEPD-PR/A) system was investigated in a modified anaerobic baffled reactor (mABR) for synchronous carbon, nitrogen, and phosphorus removal. The mABR comprising four identical compartments (i.e., C1-C4) was inoculated with precultured denitrifying glycogen-accumulating organisms (DGAOs), denitrifying polyphosphate-accumulating organisms, and anammox bacteria. After 136 days of operation, the chemical oxygen demand (COD), total nitrogen, and phosphorus removal efficiencies reached 88.6 ± 1.0, 97.2 ± 1.5, and 89.1 ± 4.2%, respectively. Network-based analysis revealed that the biofilmed community demonstrated stable nutrient removal performance under oligotrophic conditions in C4. The metagenome-assembled genomes (MAGs) such as MAG106, MAG127, MAG52, and MAG37 annotated as denitrifying phosphorus-accumulating organisms (DPAOs) and MAG146 as a DGAO were dominated in C1 and C2 and contributed to 89.2% of COD consumption. MAG54 and MAG16 annotated as Candidatus_Brocadia (total relative abundance of 16.5% in C3 and 4.3% in C4) were responsible for 74.4% of the total nitrogen removal through the anammox-mediated pathway. Functional gene analysis based on metagenomic sequencing confirmed that different compartments of the mABR were capable of performing distinct functions with specific advantageous microbial groups, facilitating targeted nutrient removal. Additionally, under oligotrophic conditions, the activity of the anammox bacteria-related genes of hzs was higher compared to that of hdh. Thus, an innovative method for the treatment of low-strength municipal and nitrate-containing wastewaters without aeration was presented, mediated by an anammox process with less land area and excellent quality effluent.

Potential therapies for HCC involving targeting the ferroptosis pathway.

Liver cancer ranks as the third leading cause of cancer-related mortality worldwide, predominantly in the form of hepatocellular carcinoma (HCC). Conventional detection and treatment approaches have proven inadequate for addressing the elevated incidence and mortality rates associated with HCC. However, a significant body of research suggests that combating HCC through the induction of ferroptosis is possible. Ferroptosis is a regulated cell death process characterized by elevated levels of reactive oxygen species (ROS) and lipid peroxide accumulation, both of which are dependent on iron levels. In recent years, there has been an increasing focus on investigating ferroptosis, revealing its potential as an inhibitory mechanism against various diseases, including tumors. Therefore, ferroptosis induction holds great promise for treating multiple types of cancers, including HCC. This article provides a review of the key mechanisms involved in ferroptosis and explores the potential application of multiple targets and pathways associated with ferroptosis in HCC treatment to improve therapeutic outcomes.

LARP4B promotes hepatocellular carcinoma progression and impairs sorafenib efficacy by activating SPINK1-mediated EGFR pathway.

La-related proteins (LARPs) regulate gene expression by binding to RNAs and exhibit critical effects on disease progression, including tumors. However, the role of LARP4B and its underlying mechanisms in the progression of hepatocellular carcinoma (HCC) remain largely unclear. In this study, we found that LARP4B expression is upregulated and correlates with poor prognosis in patients with HCC. Gain- and loss-of-function assays showed that LARP4B promotes stemness, proliferation, metastasis, and angiogenesis in vitro and in vivo. Furthermore, LARP4B inhibition enhances the antitumor effects of sorafenib and blocks the metastasis-enhancing effects of low sorafenib concentrations in HCC. Mechanistically, LARP4B expression is upregulated by METTL3-mediated N6-methyladenosine (m6A)-IGF2BP3-dependent modification in HCC. RNA- and RNA immunoprecipitation (RIP)- sequencing uncovered that LARP4B upregulates SPINK1 by binding to SPINK1 mRNA via the La motif and maintaining mRNA stability. LARP4B activates the SPINK1-mediated EGFR signaling pathway, which supports stemness, progression and sorafenib resistance in HCC. Additionally, a positive feedback loop with the LARP4B/SPINK1/p-AKT/C/EBP-ß axis is responsible for the sorafenib-therapeutic benefit of LARP4B depletion. Overall, this study demonstrated that LARP4B facilitates HCC progression, and LARP4B inhibition provides benefits to sorafenib treatment in HCC, suggesting that LARP4B might be a potential therapeutic target for HCC.

Impact of hydrogen sulfide on anammox and nitrate/nitrite-dependent anaerobic methane oxidation coupled technologies.

The coupling between anammox and nitrate/nitrite-dependent anaerobic methane oxidation (n-DAMO) has been considered a sustainable technology for nitrogen removal from sidestream wastewater and can be implemented in both membrane biofilm reactor (MBfR) and granular bioreactor. However, the potential influence of the accompanying hydrogen sulfide (H2S) in the anaerobic digestion (AD)-related methane-containing mixture on anammox/n-DAMO remains unknown. To fill this gap, this work first constructed a model incorporating the C/N/S-related bioprocesses and evaluated/calibrated/validated the model using experimental data. The model was then used to explore the impact of H2S on the MBfR and granular bioreactor designed to perform anammox/n-DAMO at practical levels (i.e., 0∼5% (v/v) and 0∼40 g/S m3, respectively). The simulation results indicated that H2S in inflow gas did not significantly affect the total nitrogen (TN) removal of the MBfR under all operational conditions studied in this work, thus lifting the concern about applying AD-produced biogas to power up anammox/n-DAMO in the MBfR. However, the presence of H2S in the influent would either compromise the treatment performance of the granular bioreactor at a relatively high influent NH4+-N/NO2--N ratio (e.g., >1.0) or lead to increased energy demand associated with TN removal at a relatively low influent NH4+-N/NO2--N ratio (e.g., <0.7). Such a negative effect of the influent H2S could not be attenuated by regulating the hydraulic residence time and should therefore be avoided when applying the granular bioreactor to perform anammox/n-DAMO in practice.

Green synthesis of Fe3O4@ceramsite from sludge improving anaerobic digestion performance of waste activated sludge.

Anaerobic digestion (AD) is a promising technique for waste management, which can achieve sludge stabilization and energy recovery. This study successfully prepared Fe3O4@ceramsite from WAS and applied it as an additive in sludge digestion, aiming to improve the conversion of organics to biomethane efficiency. Results showed that after adding the Fe3O4@ceramsite, the methane production was enhanced by 34.7% compared with the control group (88.0 ± 0.1 mL/g VS). Further mechanisms investigation revealed that Fe3O4@ceramsite enhanced digesta stability by strong buffering capacity, improved sludge conductivity, and promoted Fe (III) reduction. Moreover, Fe3O4@ceramsite has a larger surface area and better porous structure, which also facilitated AD performance. Microbial community analysis showed that some functional anaerobes related to AD such as Spirochaeta and Smithella were enriched with Fe3O4@ceramsite treatment. Potential syntrophic metabolisms between syntrophic bacteria (Syntrophomonas, associated with DIET) and methanogens were also detected in the Fe3O4@ceramsite treatment AD system.

Work Function-Guided Electrocatalyst Design.

The development of high-performance electrocatalysts for energy conversion reactions is crucial for advancing global energy sustainability. The design of catalysts based on their electronic properties (e.g., work function) has gained significant attention recently. Although numerous reviews on electrocatalysis have been provided, no such reports on work function-guided electrocatalyst design are available. Herein, a comprehensive summary of the latest advancements in work function-guided electrocatalyst design for diverse electrochemical energy applications is provided. This includes the development of work function-based catalytic activity descriptors, and the design of both monolithic and heterostructural catalysts. The measurement of work function is first discussed and the applications of work function-based catalytic activity descriptors for various reactions are fully analyzed. Subsequently, the work function-regulated material-electrolyte interfacial electron transfer (IET) is employed for monolithic catalyst design, and methods for regulating the work function and optimizing the catalytic performance of catalysts are discussed. In addition, key strategies for tuning the work function-governed material-material IET in heterostructural catalyst design are examined. Finally, perspectives on work function determination, work function-based activity descriptors, and catalyst design are put forward to guide future research. This work paves the way to the work function-guided rational design of efficient electrocatalysts for sustainable energy applications.

Single Crystal and Pentatwinned Gold Nanorods Result in Chiral Nanocrystals with Reverse Handedness.

Handedness is an essential attribute of chiral nanocrystals, having a major influence on their properties. During chemical growth, the handedness of nanocrystals is usually tuned by selecting the corresponding enantiomer of chiral molecules involved in asymmetric growth, often known as chiral inducers. We report that, even using the same chiral inducer enantiomer, the handedness of chiral gold nanocrystals can be reversed by using Au nanorod seeds with either single crystalline or pentatwinned structure. This effect holds for chiral growth induced both by amino acids and by chiral micelles. Although it was challenging to discern the morphological handedness for L-cystine-directed particles, even using electron tomography, both cases showed circular dichroism bands of opposite sign, with nearly mirrored chiroptical signatures for chiral micelle-directed growth, along with quasi-helical wrinkles of inverted handedness. These results expand the chiral growth toolbox with an effect that might be exploited to yield a host of interesting morphologies with tunable optical properties.

Efficient electrosynthesis of HO2- from air for sulfide control in sewers.

Electrochemically in-situ generation of oxygen and caustic soda is promising for sulfide management while suffers from scaling, poor inactivating capacity, hydrogen release and ammonia escape. In this study, the four-compartment electrochemical cell efficiently captured oxygen molecules from the air chamber to produce HO2- without generating toxic by-products. Meanwhile, the catalyst layer surface of PTFE/CB-GDE maintained a relatively balanced gas-liquid micro-environment, enabling the formation of enduring solid-liquid-gas interfaces for efficient HO2- electrosynthesis. A dramatic increase in HO2- generation rate from 453.3 mg L-1 h-1 to 575.4 mg L-1 h-1 was attained by advancement in operation parameters design (flow channels, electrolyte types, flow rates and circulation types). Stability testing resulted in the HO2- generation rate over 15 g L-1 and the current efficiency (CE) exceeding 85%, indicating a robust stable operational capacity. Furthermore, after 120 mg L-1 HO2- treatment, an increase of 11.1% in necrotic and apoptotic cells in the sewer biofilm was observed, higher than that achieved with the addition of NaOH, H2O2 method. The in-situ electrosynthesis strategy for HO2- represents a significance toward the practical implementation of sulfide abatement in sewers, holding the potential to treat various sulfide-containing wastewater.

High-Throughput Morphological Chirality Quantification of Twisted and Wrinkled Gold Nanorods.

Chirality in gold nanostructures offers an exciting opportunity to tune their differential optical response to left- and right-handed circularly polarized light, as well as their interactions with biomolecules and living matter. However, tuning and understanding such interactions demands quantification of the structural features that are responsible for the chiral behavior. Electron tomography (ET) enables structural characterization at the single-particle level and has been used to quantify the helicity of complex chiral nanorods. However, the technique is time-consuming and consequently lacks statistical value. To address this issue, we introduce herein a high-throughput methodology that combines images acquired by secondary electron-based electron beam-induced current (SEEBIC) with quantitative image analysis. As a result, the geometric chirality of hundreds of nanoparticles can be quantified in less than 1 h. When combining the drastic gain in data collection efficiency of SEEBIC with a limited number of ET data sets, a better understanding of how the chiral structure of individual chiral nanoparticles translates into the ensemble chiroptical response can be reached.

Reversible chirality inversion of an AuAgx-cysteine coordination polymer by pH change.

Responsive chiral systems have attracted considerable attention, given their potential for diverse applications in biology, optoelectronics, photonics, and related fields. Here we show the reversible chirality inversion of an AuAgx-cysteine (AuAgx-cys) coordination polymer (CP) by pH changes. The polymer can be obtained by mixing HAuCl4 and AgNO3 with L-cysteine (or D-cysteine) in appropriate proportions in H2O (or other surfactant solutions). Circular dichroism (CD) spectrum is used to record the strong optical activity of the AuAg0.06-L-cys enantiomer (denoted as L0.06), which can be switched to that of the corresponding D0.06 enantiomer by alkalization (final dispersion pH > 13) and can be switched back after neutralization (final dispersion pH <8). Multiple structural changes at different pH values (≈9.6, ≈13) are observed through UV-Vis and CD spectral measurements, as well as other controlled experiments. Exploration of the CP synthesis kinetics suggests that the covalent bond formation is rapid and then the conformation of the CP materials would continuously evolve. The reaction stoichiometry investigation shows that the formation of CP materials with chirality inversion behavior requires the balancing between different coordination and polymerization processes. This study provides insights into the potential of inorganic stereochemistry in developing promising functional materials.

Iron-containing nanominerals for sustainable phosphate management: A comprehensive review and future perspectives.

Adsorption, which is a quick and effective method for phosphate management, can effectively address the crisis of phosphorus mineral resources and control eutrophication. Phosphate management systems typically use iron-containing nanominerals (ICNs) with large surface areas and high activity, as well as modified ICNs (mICNs). This paper comprehensively reviews phosphate management by ICNs and mICNs in different water environments. mICNs have a higher affinity for phosphates than ICNs. Phosphate adsorption on ICNs and mICNs occurs through mechanisms such as surface complexation, surface precipitation, electrostatic ligand exchange, and electrostatic attraction. Ionic strength influences phosphate adsorption by changing the surface potential and isoelectric point of ICNs and mICNs. Anions exhibit inhibitory effects on ICNs and mICNs in phosphate adsorption, while cations display a promoting effect. More importantly, high concentrations and molecular weights of natural organic matter can inhibit phosphate adsorption by ICNs and mICNs. Sodium hydroxide has high regeneration capability for ICNs and mICNs. Compared to ICNs with high crystallinity, those with low crystallinity are less likely to desorb. ICNs and mICNs can effectively manage municipal wastewater, eutrophic seawater, and eutrophic lakes. Adsorption of ICNs and mICNs saturated with phosphate can be used as fertilizers in agricultural production. Notably, mICNs and ICNs have positive and negative effects on microorganisms and aquatic organisms in soil. Finally, this study introduces the following: trends and prospects of machine learning-guided mICN design, novel methods for modified ICNs, mICN regeneration, development of mICNs with high adsorption capacity and selectivity for phosphate, investigation of competing ions in different water environments by mICNs, and trends and prospects of in-depth research on the adsorption mechanism of phosphate by weakly crystalline ferrihydrite. This comprehensive review can provide novel insights into the research on high-performance mICNs for phosphate management in the future.

WDR4 promotes HCC pathogenesis through N7-methylguanosine by regulating and interacting with METTL1.

BACKGROUND: The N7-methylguanosine (m7G), a modification at defined internal positions within tRNAs and rRNAs, is correlated with tumor progression. Methyltransferase like 1 (METTL1)/ WD repeat domain 4 (WDR4) mediated tRNA m7G modification, which could alter many oncogenic mRNAs translation to promote progress of multiple cancer types. However, whether and how the internal mRNA m7G modification is involved in tumorigenesis remains unclear. METHODS: The immunohistochemistry assay was conducted to detect the expression of WDR4 and METTL1 in hepatocellular carcinoma (HCC) and the expression of both genes whether contributes to the prognosis of the survival rate of HCC patients. Then, CCK8, colony formation assays and tumor xenograft models were conducted to determine the effects of WDR4 on HCC cells in vitro and vivo. Besides, dot blot assay, m7G-MeRIP-seq and RNA-seq analysis were conducted to determine whether WDR4 contributes to m7G modification and underlying mechanism in HCC cells. Finally, rescue and CO-IP assay were conducted to explore whether WDR4 and METTL1 proteins form a complex in Huh7 cells. RESULTS: WDR4 modulates m7G modification at the internal sites of tumor-promoting mRNAs by forming the WDR4-METTL1 complex. WDR4 knockdown downregulated the expression of mRNA and protein levels of METTL1 gene and thus further modulate the formation of WDR4-METTL1 complex indirectly. METTL1 expression was markedly correlated with WDR4 expression in HCC tissues. HCC patients with high expression of both genes had a poor prognosis. CONCLUSIONS: WDR4 may contribute to HCC pathogenesis by interacting with and regulating the expression of METTL1 to synergistically modulate the m7G modification of target mRNAs in tumor cells.

Degradation of Chloroquine by Ammonia-Oxidizing Bacteria: Performance, Mechanisms, and Associated Impact on N2O Production.

Since the mass production and extensive use of chloroquine (CLQ) would lead to its inevitable discharge, wastewater treatment plants (WWTPs) might play a key role in the management of CLQ. Despite the reported functional versatility of ammonia-oxidizing bacteria (AOB) that mediate the first step for biological nitrogen removal at WWTP (i.e., partial nitrification), their potential capability to degrade CLQ remains to be discovered. Therefore, with the enriched partial nitrification sludge, a series of dedicated batch tests were performed in this study to verify the performance and mechanisms of CLQ biodegradation under the ammonium conditions of mainstream wastewater. The results showed that AOB could degrade CLQ in the presence of ammonium oxidation activity, but the capability was limited by the amount of partial nitrification sludge (∼1.1 mg/L at a mixed liquor volatile suspended solids concentration of 200 mg/L). CLQ and its biodegradation products were found to have no significant effect on the ammonium oxidation activity of AOB while the latter would promote N2O production through the AOB denitrification pathway, especially at relatively low DO levels (≤0.5 mg-O2/L). This study provided valuable insights into a more comprehensive assessment of the fate of CLQ in the context of wastewater treatment.

Sulfur-containing substances in sewers: Transformation, transportation, and remediation.

Sulfur-containing substances in sewers frequently incur unpleasant odors, corrosion-related economic loss, and potential human health concerns. These observations are principally attributed to microbial reactions, particularly the involvement of sulfate-reducing bacteria (SRB) in sulfur reduction process. As a multivalent element, sulfur engages in complex bioreactions in both aerobic and anaerobic environments. Organic sulfides are also present in sewage, and these compounds possess the potential to undergo transformation and volatilization. In this paper, a comprehensive review was conducted on the present status regarding sulfur transformation, transportation, and remediation in sewers, including both inorganic and organic sulfur components. The review extensively addressed reactions occurring in the liquid and gas phase, as well as examined detection methods for various types of sulfur compounds and factors affecting sulfur transformation. Current remediation measures based on corresponding mechanisms were presented. Additionally, the impacts of measures implemented in sewers on the subsequent wastewater treatment plants were also discussed, aiming to attain better management of the entire wastewater system. Finally, challenges and prospects related to the issue of sulfur-containing substances in sewers were proposed to facilitate improved management and development of the urban water system.