Mechanisms of anammox granular sludge reactor effluent as biostimulant: Shaping microenvironment for anammox metabolism.

Effluent from anammox granular sludge (AnGS) bioreactor contains microbes and microbial products. This study explored mechanisms of utilizing AnGS-effluent as biostimulant for anammox process enhancement. Compared with no AnGS-effluent supplemented control reactor, 5.0 and 1.3 times higher ammonium nitrogen and total inorganic nitrogen removal rates, respectively were obtained with continuous AnGS-effluent supplementation after 98 days' operation. Anammox bacteria from Candidatus Brocadia accounted for 0.1 % (DNA level) and 1.3 %-1.5 % (RNA level) in control reactor, and 2.9 % (DNA level) and 54.5 %-55.4 % (RNA level) in the AnGS-effluent-fed reactor. Influent microbial immigration evaluation showed that bacterial immigration via AnGS-effluent supplementation was not the main contributor to active anammox community development. Amino acids biosynthesis, B-vitamins and coenzymes metabolism related pathways were facilitated by AnGS-effluent supplementation. AnGS-effluent supplementation aided anammox metabolic activity by shaping microenvironment and microbial interactions. This study provides insights into enhancing anammox bacterial metabolism with AnGS-effluent microbial products as biostimulant.

Potential Role of the Anammoxosome in the Adaptation of Anammox Bacteria to Salinity Stress.

The underlying adaptative mechanisms of anammox bacteria to salt stress are still unclear. The potential role of the anammoxosome in modulating material and energy metabolism in response to salinity stress was investigated in this study. The results showed that anammox bacteria increased membrane fluidity and decreased mechanical properties by shortening the ladderane fatty acid chain length of anammoxosome in response to salinity shock, which led to the breakdown of the proton motive force driving ATP synthesis and retarded energy metabolism activity. Afterward, the fatty acid chain length and membrane properties were recovered to enhance the energy metabolic activity. The relative transmission electron microscopy (TEM) area proportion of anammoxosome decreased from 55.9 to 38.9% under salinity stress. The 3D imaging of the anammox bacteria based on Synchrotron soft X-ray tomography showed that the reduction in the relative volume proportion of the anammoxosome and the concave surfaces was induced by salinity stress, which led to the lower energy expenditure of the material transportation and provided more binding sites for enzymes. Therefore, anammox bacteria can modulate nitrogen and energy metabolism by changing the membrane properties and morphology of the anammoxosome in response to salinity stress. This study broadens the response mechanism of anammox bacteria to salinity stress.

Biosynthetic potential of uncultured anammox community bacteria revealed through multi-omics analysis.

Microbial secondary metabolites (SMs) and their derivatives have been widely used in medicine, agriculture, and energy. Growing needs for renewable energy and the challenges posed by antibiotic resistance, cancer, and pesticides emphasize the crucial hunt for new SMs. Anaerobic ammonium-oxidation (anammox) systems harbor many uncultured or underexplored bacteria, representing potential resources for discovering novel SMs. Leveraging HiFi long-read metagenomic sequencing, 1,040 biosynthetic gene clusters (BGCs) were unearthed from the anammox microbiome with 58% being complete and showcasing rich diversity. Most of them showed distant relations to known BGCs, implying novelty. Members of the underexplored lineages (Chloroflexota and Planctomycetota) and Proteobacteria contained lots of BGCs, showcasing substantial biosynthetic potential. Metaproteomic results indicated that Planctomycetota members harbored the most active BGCs, particularly those involved in producing potential biofuel-ladderane. Overall, these findings underscore that anammox microbiomes could serve as valuable resources for mining novel BGCs and discovering new SMs for practical application.

Transcription factor DIVARICATA1 positively modulates seed germination in response to salinity stress.

Seed germination is a critical checkpoint for plant growth under unfavorable environmental conditions. In Arabidopsis (Arabidopsis thaliana), the abscisic acid (ABA) and gibberellic acid (GA) signaling pathways play important roles in modulating seed germination. However, the molecular links between salinity stress and ABA/GA signaling are not well understood. Herein, we showed that the expression of DIVARICATA1 (DIV1), which encodes a MYB-like transcription factor, was induced by GA and repressed by ABA, salinity, and osmotic stress in germinating seeds. DIV1 positively regulated seed germination in response to salinity stress by directly regulating the expression of DELAY OF GERMINATION 1-LIKE 3 (DOGL3) and GA-STIMULATED ARABIDOPSIS 4 (GASA4) and indirectly regulating the expression of several germination-associated genes. Moreover, NUCLEAR FACTOR-YC9 (NF-YC9) directly repressed the expression of DIV1 in germinating seeds in response to salinity stress. These results help reveal the function of the NF-YC9-DIV1 module and provide insights into the regulation of ABA and GA signaling in response to salinity stress during seed germination in Arabidopsis.

The recovery potential and utilization pathway of chemical energy from wastewater pollutants during wastewater treatment in China.

Research on the potential for chemical energy recovery and the optimization of recovery pathways in different regions of China is still lacking. This study aimed to address this gap by evaluating the potential and optimize the utilization pathways for chemical energy recovery in various regions of China for achieving sustainable wastewater treatment. The results showed that the eastern and northeastern regions of China exhibited higher chemical energy levels under the existing operating conditions. Key factors affecting chemical energy recovery included chemical oxygen demand removal (ΔCOD), treatment scale, and specific energy consumption (µ) of wastewater treatment plants (WWTPs). Furthermore, the average improvement in the chemical energy recovery rate with an optimized utilization pathway was approximately 40% in the WWTPs. The use of the net-zero energy consumption (NZE) model proved effective in improving the chemical energy recovery potential, with an average reduction of greenhouse gas (GHG) emissions reaching next to 95% in the investigated WWTPs.

Optimized strategy among diet, exercise, and pharmacological interventions for nonalcoholic fatty liver disease: A network meta-analysis of randomized controlled trials.

BACKGROUND: Emerging treatment methods, including exercise, diet, and drugs, for nonalcoholic fatty liver disease have been proposed. However, the differences in their efficacy have not been determined. We aimed to compare the effects of these treatments excluding surgery via a systematic review and network meta-analysis of randomized controlled trials. DATA SOURCE: The data sources included PubMed, Embase, Web of Science and Cochrane up to February 1st, 2023. The endpoints consisted of body mass index (BMI), serum markers of metabolism and liver injury markers, liver fat content, and stiffness. RESULTS: A total of 174 studies with 10,183 patients were included in this meta-analysis. In terms of improving BMI, Pan-agonist of peroxisome proliferator-activated receptors (PPAR) is the best treatment with the highest SUCRA (surface under the cumulative ranking) of 84.8% (mean = -3.40, 95% CI -5.55, -1.24) by the comparative effectiveness ranking. GLP-1 (glucagon-like peptide-1) has the best effect in improving the liver fat content based on the MRI-PDFF, steatosis score (SUCRA 99.7%, mean = -2.19, 95% CI -2.90, -1.48) and ballooning score (SUCRA 61.2%, mean = -0.82, 95% CI -4.46, 2.83). CONCLUSIONS: Pan-agonist of PPAR was the most efficacious regimen in lowering BMIs, whereas GLP-1R agonists achieved the highest efficacy of steatosis improvement in this network meta-analysis.

The symptoms and interval of Omicron SARS-CoV-2 reinfection among healthcare workers in a hospital of Southern China: a cross-sectional study.

BACKGROUND: The prevalence and distinction between first Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and reinfection with the Omicron variant among healthcare workers (HCWs) remain unclear. METHODS: A cross-sectional study was conducted at a hospital in Southern China. The study included 262 HCWs who were infected with SARS-CoV-2 between April and June 2023, with 101 cases of first infection and 161 ones of reinfection. Student's t-test, Analysis of Variance (ANOVA), and Mann-Whitney U tests were used based on the distribution of quantitative variables. Pearson's chi-square and Fisher's exact tests were used based on the expected frequencies of categorical variables. RESULTS: The reinfection rate among HCWs was 11.5% (161/1406). The majority of the infected HCWs were female (212/262, 80.9%, first infection vs. reinfection: 76.2% vs. 83.9%). The nursing staff, had the highest percentage of SARS-CoV-2 infection (42.0%), especially of its reinfection (47.8%). Out of the 262 infected individuals, 257 had received SARS-CoV-2 vaccination, primarily inactivated vaccines (243/257, 91.1%). The first infection group, which received four doses (24, 23.8%), was significantly higher than that in the reinfection group (6, 3.7%) (P < 0.001). The proportion of asymptomatic infections among HCWs in the two groups was 1.0% and 1.2%. The main symptoms during the first infection and reinfection were fever (83.2% and 50.9%) and sore throat (78.2% and 77.0%). There were significant differences in the prevalence of fever (83.2% vs. 50.9%), rhinorrhea (45.5% vs. 60.9%) and myalgia (56.4% vs. 37.9%) between the first infection and reinfection (P < 0.05). The average interval for SARS-CoV-2 reinfection was 149.9 (range: 114-182, SD = 11.9) days. Notably, physicians had the shortest average interval of 142.8 (8.8) days, while management and administrative staff had the longest average interval of 153.8 (13.5) days. CONCLUSIONS: Although the symptoms of HCWs during reinfection with SARS-CoV-2 were milder, the high reinfection rate and short interval between infections indicate the need to enhance monitoring and protective measures for HCWs during the epidemic.

New insights into functional divergence and adaptive evolution of uncultured bacteria in anammox community by complete genome-centric analysis.

Anaerobic ammonium-oxidation (anammox) bacteria play a crucial role in global nitrogen cycling and wastewater nitrogen removal, but they share symbiotic relationships with various other microorganisms. Functional divergence and adaptive evolution of uncultured bacteria in anammox community remain underexplored. Although shotgun metagenomics based on short reads has been widely used in anammox research, metagenome-assembled genomes (MAGs) are often discontinuous and highly contaminated, which limits in-depth analyses of anammox communities. Here, for the first time, we performed Pacific Biosciences high-fidelity (HiFi) long-read sequencing on the anammox granule sludge sample from a lab-scale bioreactor, and obtained 30 accurate and complete metagenome-assembled genomes (cMAGs). These cMAGs were obtained by selecting high-quality circular contigs from initial assemblies of long reads generated by HiFi sequencing, eliminating the need for Illumina short reads, binning, and reassembly. One new anammox species affiliated with Candidatus Jettenia and three species affiliated with novel families were found in this anammox community. cMAG-centric analysis revealed functional divergence in general and nitrogen metabolism among the anammox community members, and they might adopt a cross-feeding strategy in organic matter, cofactors, and vitamins. Furthermore, we identified 63 mobile genetic elements (MGEs) and 50 putative horizontal gene transfer (HGT) events within these cMAGs. The results suggest that HGT events and MGEs related to phage and integration or excision, particularly transposons containing tnpA in anammox bacteria, might play important roles in the adaptive evolution of this anammox community. The cMAGs generated in the present study could be used to establish of a comprehensive database for anammox bacteria and associated microorganisms. These findings highlight the advantages of HiFi sequencing for the studies of complex mixed cultures and advance the understanding of anammox communities.

L-shaped association between the GA/HbA1c ratio and all-cause mortality in U.S. adults with NAFLD: a cross-sectional study from the NHANES 1999-2004.

OBJECTIVE: It is currently unclear whether there is a relationship between the ratio of glycated albumin to hemoglobin A1c (GA/HbA1c) and mortality in individuals diagnosed with nonalcoholic fatty liver disease (NAFLD). The primary objective of the study was to investigate the relationship between the GA/HbA1c ratio and all-cause mortality in adults with NAFLD in the U.S. METHODS: The investigation included a total of 5,295 individuals aged ≥ 18 years who were diagnosed with NAFLD, these individuals were selected from the National Health and Nutrition Examination Survey conducted between 1999 and 2004. To evaluate the outcomes of death, the researchers relied on National Death Index (NDI) records up to December 31, 2019. To better understand the nonlinear relationship between the GA/HbA1c ratio and mortality among individuals with NAFLD, this study employed both subgroup and sensitivity analyses. Furthermore, Cox proportional hazards models and two-part Cox proportional hazards model were utilized. RESULTS: The study included a total of 5,295 adult patients with NAFLD in the U.S. During a median follow-up period of 16.9 years, there were 1,471 recorded deaths, including 419 cardiovascular deaths. After accounting for various factors, a higher GA/HbA1c ratio exhibited a positive and nonlinear association with an increased risk of all-cause mortality in patients with NAFLD. Furthermore, the study revealed an L-shaped relationship between the GA/HbA1c ratio and all-cause mortality, with the inflection point occurring at a GA/HbA1c ratio of 2.21. When the GA/HbA1c ratio exceeded 2.21, each 1-unit increase in the ratio was associated with a 33% increase in the adjusted hazard ratio (HR 1.33; 95% CI 1.14, 1.60) for all-cause mortality. CONCLUSIONS: A nonlinear correlation between the ratio of GA to HbA1c and all-cause mortality was observed in U.S. adults with NAFLD. In addition, an elevated GA/HbA1c ratio was linked to an increased risk of all-cause mortality in these patients.

Motility behavior and physiological response mechanisms of aerobic denitrifier, Enterobacter cloacae strain HNR under high salt stress: Insights from individual cells to populations.

The motility behaviors at the individual-cell level and the collective physiological responsive behaviors of aerobic denitrifier, Enterobacter cloacae strain HNR under high salt stress were investigated. The results revealed that as salinity increased, electron transport activity and adenosine triphosphate content decreased from 15.75 µg O2/g/min and 593.51 mM/L to 3.27 µg O2/g/min and 5.34 mM/L, respectively, at 40 g/L, leading to a reduction in the rotation velocity and vibration amplitude of strain HNR. High salinity stress (40 g/L) down-regulated genes involved in ABC transporters (amino acids, sugars, metal ions, and inorganic ions) and activated the biofilm-related motility regulation mechanism in strain HNR, resulting in a further decrease in flagellar motility capacity and an increase in extracellular polymeric substances secretion (4.08 mg/g cell of PS and 40.03 mg/g cell of PN at 40 g/L). These responses facilitated biofilm formation and proved effective in countering elevated salt stress in strain HNR. Moreover, the genetic diversity associated with biofilm-related motility regulation in strain HNR enhanced the adaptability and stability of the strain HNR populations to salinity stress. This study enables a deeper understanding of the response mechanism of aerobic denitrifiers to high salt stress.

Characterization of SARS-CoV-2-specific humoral immunity and associated factors in the healthy population post-vaccination.

OBJECTIVES: To investigate factors that may influence humoral immunity post-vaccination with a COVID-19-inactivated vaccine (SC2IV). METHODS: A total of 1596 healthy individuals from the Seventh Affiliated Hospital, Sun Yat-sen University (1217) and Shenzhen Baotian Hospital (379) were enrolled in this study among which 694 and 218 participants were vaccinated with two-dose SC2IV, respectively. Physical examination indices were recorded. The levels of neutralizing antibody (NA), Spike IgG, receptor-binding domain (RBD) IgG, RBD IgG + IgM + IgA, and nucleocapsid IgG of SARS-CoV-2 were measured by a non-virus ELISA kit. Multiple statistical analyses were carried out to identify factors that influence humoral immunity post-vaccination. RESULTS: The two-dosage vaccination could induce NA in more than 90 % of recipients. The NA has the strongest correlation with anti-RBD IgG. Age is the most important independent index that affects the NA level, while basophil count, creatine kinase-MB, mean corpuscular hemoglobin, the ratio of albumin to urine creatinine, and thyroglobulin antibody have relatively minor contributions. Indices that affect the NA level were different between males and females. Antibodies targeting other epitopes of SARS-CoV-2 were detected in recipients without anti-RBD. CONCLUSIONS: The factors identified in association with the NA level post-vaccination may help to evaluate the protective effect, risk of re-infection, the severity of symptoms, and prognosis for vaccine recipients in clinical.

Antibiotic prophylaxis after 48 h postoperatively are not associated with decreased surgical site infections and other healthcare associated infections in pancreatic surgery patients: a retrospective cohort study.

BACKGROUND: It is controversial whether antibiotic should be used prophylactically 48 h after pancreatic surgery. Hence, the association of antibiotic prophylaxis (AP) after 48 h postoperatively with the incidence of surgical site infections (SSIs) and other healthcare-associated infections (HAIs) in patients receiving pancreatic surgery was evaluated. METHODS: A retrospective cohort analysis was performed on 1073 patients who underwent pancreatic surgery. These patients were categorized into the non-AP after 48 h postoperatively group (n = 963) and the AP after 48 h postoperatively group (n = 110) based on whether or not they obtained AP from 48 h to 30 days after surgery. Outcomes included SSIs and other HAIs. RESULTS: The incidence of SSIs in the non-AP after 48 h postoperatively group (98/963, 10.2%) was notably lower than that in the AP after 48 h postoperatively group (22/110, 20.0%) (P = 0.002). Other HAIs incidence was not significantly different between the non-AP after 48 h postoperatively group (77/963, 8.0%) and the AP after 48 h postoperatively group (11/110, 10.0%) (P = 0.468). Multiple regression analysis demonstrated that AP after 48 h postoperatively was a risk factor for SSIs (OR = 2.14, 95% CI 1.28-3.59) but not for other HAIs (OR = 1.24, 95% CI 0.63-2.42) after adjustment for age, gender, and diabetes. Subsequent to adjustment for all confounding factors, AP after 48 h postoperatively was not a influence factor for SSIs (OR = 2.13, 95% CI 0.76-5.99) and other HAIs (OR = 3.69, 95% CI 0.99-13.81). CONCLUSIONS: AP after 48 h postoperatively following pancreatic surgery was not associated with the lower morbidity rate of SSIs and other HAIs. Nonetheless, this study may facilitate further development of strategies towards standardization of the duration of AP management of pancreatic surgery.

Fate of iron nanoparticles in anammox system: Dissolution, migration and transformation.

Iron nanoparticles (FeNPs) are commonly used in various industrial processes, leading to their release into the environment and eventual entrance into wastewater treatment plants (WWTPs). FeNPs undergo dissolution, migration, and transformation in WWTPs, which can potentially affect the stable operation of anaerobic ammonia oxidation (anammox) systems and may be discharged with wastewater or biomass. To better understand the fate of FeNPs in anammox systems, exposure experiments were conducted using anammox granular sludges (AnGS) and FeNPs. Results demonstrated that FeNPs released Fe2+ upon contact with water, with a portion being bound to functional groups in extracellular polymeric substances (EPS) and the rest entering the bacteria to form highly absorbable substances. A significant amount of FeNPs was observed to cover the surface of AnGS or aggregate and deposit at the bottom of the reactor, eventually converting into Fe3O4 and stably existing within the anammox system. The findings of this study clarify the fate of FeNPs in anammox systems and provide important insights into the stable operation of anammox systems under FeNPs exposure.

The prognostic and immunological role of FKBP1A in an integrated muti-omics cancers analysis, especially lung cancer.

BACKGROUND AND AIM: FKBP1A, a gene encoding the FK506-binding protein 1A, has emerged as a significant player in cancer progression and prognosis. This study aimed to comprehensively investigate the multifaceted role of FKBP1A in cancer, focusing on its differential expression patterns, prognostic implications, genetic alterations, and associations with the tumor microenvironment. METHODS AND RESULTS: Using large-scale datasets, including GTEx, TCGA, HPA, and cBioPortal, we analyzed FKBP1A expression across normal tissues and various cancer types. Our findings revealed that FKBP1A exhibited aberrant upregulation in most human cancers, making it a potential biomarker for malignancy. Moreover, FKBP1A expression correlated with poor overall survival, disease-specific survival, disease-free interval, and progression-free interval in several cancers, indicating its prognostic significance. Genetic alteration analysis showed that FKBP1A gene amplification was prevalent, particularly in ovarian cancer. Furthermore, FKBP1A expression was associated with tumor mutational burden and microsatellite instability, highlighting its potential involvement in tumor-immune response. Notably, FKBP1A expression positively correlated with stromal and immune cell scores, suggesting its role in shaping the tumor microenvironment. Additionally, according to the functional enrichment analysis, experimental validation in lung adenocarcinoma confirmed the role of FKBP1A through the regulation of EGFR signaling by apoptosis, which is consistent with drug sensitivity analysis to some extent. CONCLUSION: In conclusion, FKBP1A exhibits differential expression in cancer, serves as a prognostic indicator, undergoes genetic alterations, and influences the tumor-immune microenvironment. These findings shed light on the multifaceted role of FKBP1A in cancer development and progression, suggesting its potential as a therapeutic target and guidance of clinical drugs selection, and provide valuable insights into patient prognosis for interventions based on pharmaceuticals.

Effect of food-to-microorganisms ratio on aerobic granular sludge settleability: Microbial community, potential roles and sequential responses of extracellular proteins and polysaccharides.

The food-to-microorganism ratio (F/M) is an important parameter in wastewater biotreatment that significantly affects the granulation and settleability of aerobic granular sludge (AGS). Hence, understanding the long-term effects and internal mechanisms of F/M on AGS settling performance is essential. This study investigated the relationship between F/M and the sludge volume index (SVI) within a range of 0.23-2.50 kgCOD/(kgMLVSS·d). Thiothrix and Candidatus_Competibacter were identified as two dominant bacterial genera influencing AGS settling performance. With F/M increased from 0.27 kgCOD/(kgMLVSS·d) to 1.53 kgCOD/(kgMLVSS·d), the abundance of Thiothrix significantly increased from 0.20% to 27.02%, and the hydrophobicity of extracellular proteins (PN) decreased, which collectively reduced AGS settling performance. However, under high-F/M conditions, the gel-like polysaccharides (PS) effectively retained the granular biomass by binding to the highly abundant Thiothrix (53.65%). The progressive increment in biomass led to a concomitant reduction in F/M, resulting in the recovery of AGS settleability. In addition, two-dimensional correlation infrared spectroscopy analysis revealed the preferential responses of PN and PS to the increase and decrease of F/M, and the content and characteristics of PN and PS played important roles in granular settling. The study provides insight into the microbial composition and the potential role of extracellular polymer substances in the AGS sedimentation behavior, offering valuable theoretical support for stable AGS operation.

Body composition and risk of liver cancer: a population-based prospective cohort study on gender difference.

Background: Obesity is a common and highly convincing risk factor for many cancers, including liver cancer. Sex disparities in the body composition and regulatory mechanisms involved in energy homeostasis may contribute to the difference in the incidence of cancer. However, evidence on the gender-specific association between body composition and liver cancer incidence is limited. We performed this study to investigate the linear and non-linear associations of body composition with liver cancer risk by gender. Materials and methods: This prospective analysis included 4,75,659 participants free of cancer, based on the UK Biobank. We used Cox proportional hazard models to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) after adjusting for potential confounders. Restricted cubic spline was performed to investigate the potential non-linear associations. Results: During a median follow-up, 275 cases (174 male patients and 101 female patients) of liver cancer were identified. Male patients in the highest body fat percentage group are more likely to develop liver cancer (HR = 1.89, 95% CI: 1.17-3.03) compared with those in the lowest group. The one-unit increase of whole-body fat mass, arm fat mass, and trunk fat mass was associated with 1.03-, 1.14-, and 1.05-fold increased risk of liver cancer in male subjects, respectively. U-shaped associations of body composition with liver cancer risk were observed in the female subjects. Both high and low levels of whole-body fat-free mass, particularly in the arm and trunk, were associated with an increased risk of liver cancer. Conclusion: This study found a gender-specific association between body composition and liver cancer risk and provided evidence for individualized weight management for the prevention of liver cancer.

Potential role of quorum quenching activity of silver nanoparticles in controlling non-filamentous bulking within activated sludge process.

The effective prevention and control of non-filamentous bulking is a significant challenge. In this study, the underlying effect of quorum sensing (QS) on inducing non-filamentous bulking and the maintenance effect of silver nanoparticles (AgNPs) on sludge floc stability, aggregation and settleability based on the quorum quenching (QQ) activity during non-filamentous bulking were investigated. The results showed that the concentration of N-acyl homoserine lactone (AHL) increased significantly in the activated sludge system at a high organic load rate (OLR), triggering the AHL-mediated QS. Additionally, the triggered QS promoted exopolysaccharide secretion, reducing the surface charge and hydrophobicity of the sludge aggregates, and further deteriorating the settleability of the sludge aggregates. AgNPs, a quorum sensing inhibitor (QSI), inhibited the AHL-QS based on QQ activity under high OLR, which maintained the physicochemical properties of extracellular polymeric substances (EPS). AgNPs-QQ maintained the surface energy barrier and electrostatic barrier of sludge aggregates and the gel properties of exopolysaccharides, which is favorable for microbial aggregation. The appropriate concentrations of AgNPs (≤10 mg/L) had no negative effect on biological nutrient removal in the sequencing batch reactors (SBRs) at the high organic loading. Therefore, AgNPs effectively prevent and control non-filamentous bulking by their QQ activity in the activated sludge process. Thus, the present study provided new insights into controlling non-filamentous bulking during the activated sludge process.

Unraveling the structure and function of bacterioferritin in Candidatus Kuenenia stuttgartiensis: Iron storage sites maintain cellular iron homeostasis.

Anammox bacteria rely heavily on iron and have many iron storage sites. However, the biological significance of these iron storage sites has not been clearly defined. In this study, we explored the properties and location of iron storage sites to better understand their cellular function. To do this, the Candidatus Kuenenia stuttgartiensis iron storage protein, bacterioferritin (K.S Bfr), was successfully expressed and purified. In vitro, correctly assembled globulins were observed by transmission electron microscopy. The self-assembled K.S Bfr has active redox and can bind Fe2+ and mineralize it in the protein cavity. In vivo, engineered bacteria with K.S Bfr showed good adaptability to Fe2+, with a survival rate of 78.9% when exposed to 5 mM Fe2+, compared with only 66.0% for wild-type bacteria lacking K.S Bfr. A potential iron regulatory strategy similar to that of Anammox was identified in transcriptomic analysis of engineered bacteria. This system may be controlled by the iron uptake regulator Furto transport Fe2+ via FeoB and store excess Fe2+ in K.S Bfr to maintain cellular homeostasis. K.S Bfr has superior iron storage capacity both intracellularly and in vitro. The discovery of K.S Bfr reveals the storage location of iron-rich nanoparticles, increases our understanding of the adaptability of iron-dependent bacteria to Fe2+, and suggests possible iron regulation strategies in Anammox bacteria.

Non-filamentous sludge bulking induced by exopolysaccharide variation in structure and properties during aerobic granulation.

The forming mechanism of non-filamentous sludge bulking during aerobic granulation were investigated basing on three feeding strategies (R1 direct aeration after fast feeding, R2 anaerobic stirring after fast feeding and R3 anaerobic plug-flow slow feeding). Results showed that strong selection stress (shortening settling time) led to a sharp flocs washout and the subsequent increase of food to microorganisms (F/M) in R1 and R3 reactors, but not found in R2 due to the different strategies of feeding modes. With the increase of F/M, zeta potential and hydrophobicity of sludge surfaces significantly decreased and thus leading to an enhanced repulsive force and energy barriers for sludge aggregation. Particularly, when F/M exceeded 1.2 kgCOD/(kgMLSS·d), non-filamentous sludge bulking was ultimately triggered in R1 and R3. Further analysis showed that massive extracellular exopolysaccharide (PS) accumulated on the surfaces of non-filamentous bulking sludge due to the increased abundance of the microorganisms related to PS secretion during sludge bulking. In addition, significantly increased intracellular second messenger (c-di-GMP), a key substance regulating PS biosynthesis, was confirmed via its concentration determination as well as microbial function prediction analysis, which played a critical role in sludge bulking. Combing with the systematic detection from surface plasmon resonance system, rheometer and size-exclusion chromatography-multiangle laser light detection-refractive index system, higher molecular weight, compact conformation, higher viscosity and higher hydrophilicity was determined in sludge bulking PS relative to PS extracted from non-filamentous bulking sludge. Clearly, the changes of PS (content, structures and properties) driven by c-di-GMP are the dominant mechanism for the formation of non-filamentous sludge bulking during aerobic granulation. This work could provide theoretical support for successful start-up and application of aerobic granular sludge technology.

Associations of dietary antioxidant micronutrients with the prevalence of obesity in adults.

Background: Antioxidant micronutrients have a therapeutic potential for clinical treatment of obesity. NO research, however, has examined the connection between the complex level of dietary antioxidants and obesity. Materials and methods: We mainly aimed to investigate the relationship between a combination of antioxidants and obesity using the database of the national health and nutrition examination survey (NHANES). This cross-sectional study contains a survey of 41,021 people (≥18 years) in total ranging from 2005 to 2018. Multivariate logistic and weighted quantile sum (WQS) regression were performed to investigate the associations between these antioxidants, both individually and collectively, and the prevalence of obesity. The restricted cubic spline (RCS) regression was also utilized to analyze the linearity of these associations. Results: According to multivariate logistic models, we found that the levels of most antioxidants in the highest quartile were independently related to a lower prevalence of obesity, while a reverse result was observed in selenium (p for trend <0.05). The WQS index revealed that a total of the 11 antioxidants is negatively related to the prevalence of obesity and abdominal obesity (all p<0.001), and iron/vitamin C have the greatest weight in the negative associations between antioxidant complex and obesity, as well as abdominal obesity. In addition, the RCS regression showed that retinol, vitamin A, α-carotene, ß-carotene, ß-cryptoxanthin, vitamin C, iron, and copper all had a non-linear association with obesity. Threshold effect analysis demonstrated that the inflection points of retinol, vitamin A, α-carotene, ß-carotene, ß-cryptoxanthin, vitamin C, iron, and cooper were 235.57, 374.81, 58.89, 891.44, 30.70, 43,410.00, 11,240.00, and 990.00 µg/day, respectively. Conclusion: Our study found that a high level of a complex of 11 dietary antioxidants is related to a lower prevalence of obesity and abdominal obesity, among this inverse associations iron and vitamin C have the greatest weight.