Histone Lactylation Boosts Reparative Gene Activation Post-Myocardial Infarction.

BACKGROUND: Inflammation resolution and cardiac repair initiation after myocardial infarction (MI) require timely activation of reparative signals. Histone lactylation confers macrophage homeostatic gene expression signatures via transcriptional regulation. However, the role of histone lactylation in the repair response post-MI remains unclear. We aimed to investigate whether histone lactylation induces reparative gene expression in monocytes early and remotely post-MI. METHODS: Single-cell transcriptome data indicated that reparative genes were activated early and remotely in bone marrow and circulating monocytes before cardiac recruitment. Western blotting and immunofluorescence staining revealed increases in histone lactylation levels, including the previously identified histone H3K18 lactylation in monocyte-macrophages early post-MI. Through joint CUT&Tag and RNA-sequencing analyses, we identified Lrg1, Vegf-a, and IL-10 as histone H3K18 lactylation target genes. The increased modification and expression levels of these target genes post-MI were verified by chromatin immunoprecipitation-qPCR and reverse transcription-qPCR. RESULTS: We demonstrated that histone lactylation regulates the anti-inflammatory and pro-angiogenic dual activities of monocyte-macrophages by facilitating reparative gene transcription and confirmed that histone lactylation favors a reparative environment and improves cardiac function post-MI. Furthermore, we explored the potential positive role of monocyte histone lactylation in reperfused MI. Mechanistically, we provided new evidence that monocytes undergo metabolic reprogramming in the early stage of MI and demonstrated that dysregulated glycolysis and MCT1 (monocarboxylate transporter 1)-mediated lactate transport promote histone lactylation. Finally, we revealed the catalytic effect of IL (interleukin)-1ß-dependent GCN5 (general control non-depressible 5) recruitment on histone H3K18 lactylation and elucidated its potential role as an upstream regulatory element in the regulation of monocyte histone lactylation and downstream reparative gene expression post-MI. CONCLUSIONS: Histone lactylation promotes early remote activation of the reparative transcriptional response in monocytes, which is essential for the establishment of immune homeostasis and timely activation of the cardiac repair process post-MI.

Water-Soluble Polysaccharides Extracted from Pueraria lobata Delay Aging of Caenorhabditis elegans under Heat Stress.

Pueraria lobata is a perennial legume, commonly used as a food source in China. The polysaccharides extracted from P. lobata have demonstrated various biological activities. However their anti-aging effects and the underline mechanisms are largely unknown. In this study, water-soluble polysaccharides (WSPS) from P. lobata were extracted and demonstrated antioxidant activity against DPPH radicals and hydroxyl radicals in vitro. Using nematode Caenorhabditis elegans as a model, we found that WSPS remarkably prolonged the survival, increased growth and locomotion under heat stress. To investigate the possible mechanism, the levels of reactive oxygen species (ROS) and lipid peroxidation product malondialdehyde (MDA) were determined. WSPS significantly decreased ROS and MDA levels which is consistent with increased activity of superoxide dismutase (SOD). Meanwhile, WSPS upregulated the expression of stress resistance genes sod-1, sod-5, hsf-1, hsp-12.6, hsp-16.2, skn-1 and gst-4. Together, these results suggest that the anti-aging activity of WSPS under heat stress was mediated most likely by activation of the target genes of heat-shock transcription factor (HSF)-1 and skinhead (SKN)-1, and thus inducing endogenous ROS scavenging response.

Circular RNA circSnx5 Controls Immunogenicity of Dendritic Cells through the miR-544/SOCS1 Axis and PU.1 Activity Regulation.

Dendritic cells (DCs) can orchestrate either immunogenic or tolerogenic responses to relay information on the functional state. Emerging studies indicate that circular RNAs (circRNAs) are involved in immunity; however, it remains unclear whether they govern DC development and function at the transcriptional level. In this study, we identified a central role for a novel circRNA, circSnx5, in modulating DC-driven immunity and tolerance. Ectopic circSnx5 suppresses DC activation and promotes the development of tolerogenic functions of DCs, while circSnx5 knockdown promotes their activation and inflammatory phenotype. Mechanistically, circSnx5 can act as a miR-544 sponge to attenuate miRNA-mediated target depression on suppressor of cytokine signaling 1 (SOCS1) and inhibit nuclear translocation of PU.1, regulating DC activation and function. Furthermore, the main splicing factors (SFs) were identified in DCs, of which heterogeneous nuclear ribonucleoprotein (hnRNP) C was essential for circSnx5 generation. Moreover, our data demonstrated that vaccination with circSnx5-conditioned DCs prolonged cardiac allograft survival in mice and alleviated experimental autoimmune myocarditis. Taken together, our results revealed circSnx5 as a key modulator to fine-tune DC function, suggesting that circSnx5 may serve as a potential therapeutic avenue for immune-related diseases.

Selenium Stimulates Cadmium Detoxification in Caenorhabditis elegans through Thiols-Mediated Nanoparticles Formation and Secretion.

Antagonism between heavy metal and selenium (Se) could significantly affect their biotoxicity, but little is known about the mechanisms underlying such microbial-mediated antagonistic processes as well as the formed products. In this work, we examined the cadmium (Cd)-Se interactions and their fates in Caenorhabditis elegans through in vivo and in vitro analysis and elucidated the machinery of Se-stimulated Cd detoxification. Although the Se introduction induced up to 3-fold higher bioaccumulation of Cd in C. elegans than the Cd-only group, the nematode viability remained at a similar level to the Cd-only group. The relatively lower level of reactive oxygen species in the Se & Cd group confirms a significantly enhanced Cd detoxification by Se. The Cd-Se interaction, mediated by multiple thiols, including glutathione and phytochelatin, resulted in the formation of less toxic cadmium selenide (CdSe)/cadmium sulfide (CdS) nanoparticles. The CdSe/CdS nanoparticles were mainly distributed in the pharynx and intestine of the nematodes, and continuously excreted from the body, which also benefitted the C. elegans survival. Our findings shed new light on the microbial-mediated Cd-Se interactions and may facilitate an improved understanding and control of Cd biotoxicity in complicated coexposure environments.

Morphology-dependent antimicrobial activity of Cu/CuxO nanoparticles.

Cu/CuxO nanoparticles (NPs) with different morphologies have been synthesized with glucose as a reducing agent. The X-ray diffraction and Scanning electron microscopy imaging show that the Cu/CuxO NPs have fine crystalline peaks with homogeneous polyhedral, flower-like, and thumbtack-like morphologies. Their antimicrobial activities were evaluated on inactivation of Escherichia coli using a fluorescence-based live/dead staining method. Dissolution of copper ions from these NPs was determined. Results demonstrated a significant growth inhibition for these NPs with different morphologies, and the flower-like Cu/CuxO NPs were the most effective form, where more copper ions were dissolved into the culture media. Surface free energy calculations based on first-principle density functional theory show that different crystal facets of the copper NPs have diverse surface energy, indicating the highest reactivity of the flower-like NPs, which is consistent with the results from the dissolution study and antimicrobial activity test. Together, these results suggest that the difference between the surface free energy may be a cause for their morphology-dependent antimicrobial activity.

Application of a weak magnetic field to improve microbial fuel cell performance.

Microbial fuel cells (MFCs) have emerged as a promising technology for wastewater treatment with concomitant energy production but the performance is usually limited by low microbial activities. This has spurred intensive research interest for microbial enhancement. This study demonstrated an interesting stimulation effect of a static magnetic field (MF) on sludge-inoculated MFCs and explored into the mechanisms. The implementation of a 100-mT MF accelerated the reactor startup and led to increased electricity generation. Under the MF exposure, the activation loss of the MFC was decreased, but there was no increased secretion of redox mediators. Thus, the MF effect was mainly due to enhanced bioelectrochemical activities of anodic microorganisms, which are likely attributed to the oxidative stress and magnetohydrodynamic effects under an MF exposure. This work implies that weak MF may be applied as a simple and effective approach to stimulate microbial activities for various bioelectrochemical energy production and decontamination applications.

Light-driven microbial dissimilatory electron transfer to hematite.

The ability of dissimilatory metal-reducing microorganisms (DMRM) to conduct extracellular electron transfer with conductive cellular components grants them great potential for bioenergy and environmental applications. Crystalline Fe(III) oxide, a type of widespread electron acceptor for DMRM in nature, can be excited by light for photocatalysis and microbial culture-mediated photocurrent production. However, the feasibility of direct electron transfer from living cells to light-excited Fe(III) oxides has not been well documented and the cellular physiology in this process has not been clarified. To resolve these problems, an electrochemical system composed of Geobacter sulfurreducens and hematite (α-Fe2O3) was constructed, and direct electron transfer from G. sulfurreducens cells to the light-excited α-Fe2O3 in the absence of soluble electron shuttles was observed. Further studies evidenced the efficient excitation of α-Fe2O3 and the dependence of photocurrent production on the biocatalytic activity. Light-induced electron transfer on the cell-α-Fe2O3 interface correlated linearly with the rates of microbial respiration and substrate consumption. In addition, the G. sulfurreducens cells were found to survive on light-excited α-Fe2O3. These results prove a direct mechanism behind the DMRM respiration driven by photo-induced charge separation in semiconductive acceptors and also imply new opportunities to design photo-bioelectronic devices with living cells as a catalyst.

Low-intensity pulsed ultrasound protects from inflammatory dilated cardiomyopathy through inciting extracellular vesicles.

AIMS: CD4+ T cells are activated during inflammatory dilated cardiomyopathy (iDCM) development to induce immunogenic responses that damage the myocardium. Low-intensity pulsed ultrasound (LIPUS), a novel physiotherapy for cardiovascular diseases, has recently been shown to modulate inflammatory responses. However, its efficacy in iDCM remains unknown. Here, we investigated whether LIPUS could improve the severity of iDCM by orchestrating immune responses and explored its therapeutic mechanisms. METHODS AND RESULTS: In iDCM mice, LIPUS treatment reduced cardiac remodelling and dysfunction. Additionally, CD4+ T cell inflammatory responses were suppressed. LIPUS increased Treg cells while decreasing Th17 cells. LIPUS mechanically stimulates endothelial cells, resulting in increased secretion of extracellular vesicles (EVs), which are taken up by CD4+ T cells and alter their differentiation and metabolic patterns. Moreover, EVs selectively loaded with microRNA (miR)-99a are responsible for the therapeutic effects of LIPUS. The hnRNPA2B1 translocation from the nucleus to the cytoplasm and binding to caveolin-1 and miR-99a confirmed the upstream mechanism of miR-99a transport. This complex is loaded into EVs and taken up by CD4+ T cells, which further suppress mTOR and TRIB2 expression to modulate cellular differentiation. CONCLUSION: Our findings revealed that LIPUS uses an EV-dependent molecular mechanism to protect against iDCM progression. Therefore, LIPUS is a promising new treatment option for iDCM.

Tailor-made Au@Ag core-shell nanoparticle 2D arrays on protein-coated graphene oxide with assembly enhanced antibacterial activity.

Water-dispersible two-dimensional (2D) assemblies of Au@Ag core-shell nanoparticles are obtained through a highly selective electroless silver deposition on pre-assembled gold nanoparticles on bovine serum albumin (BSA)-coated graphene oxide (BSA-GO). While neither BSA-GO nor AuNP-decorated BSA-GO shows any antibacterial ability, the silver-coated GO@Au nanosheets (namely GO@Au@Ag) exhibit an enhanced antibacterial activity against Gram-negative Escherichia coli (E. coli) bacteria, superior to unassembled Au@Ag nanoparticles and even ionic Ag. Such an improvement may be attributed to the increased local concentration of silver nanoparticles around a bacterium and a polyvalent interaction with the bacterial surface. In addition, the colloidal stability of this novel nano-antimicrobial against the formation of random nanoparticle aggregates guarantees a minimized activity loss of the Au@Ag nanoparticles. The antibacterial efficacy of GO@Au@Ag is less sensitive to the existence of Cl⁻, in comparison with silver ions, providing another advantage for wound dressing applications. Our research unambiguously reveals a strong and very specific interaction between the GO@Au@Ag nanoassembly and E. coli, which could be an important clue toward a rational design, synthesis and assembly of innovative and highly active antibacterial nanomaterials.

Essential roles of p53 and MAPK cascades in microcystin-LR-induced germline apoptosis in Caenorhabditis elegans.

Hepatotoxin microcystin-LR (MC-LR) can induce apoptosis in a variety of cells. However, the underlying pathways of MC-LR-induced apoptosis have not been well elucidated yet. To find out the roles of underlying pathways in apoptosis signaling in response to MC-LR, germ cell corpses were scored in Caenorhabditis elegans N2 wild type and strains carrying mutated alleles homologous to their mammalian counterparts. We found that exposure to MC-LR at 1.0 µg/L significantly increased germline apoptosis in N2. Germline apoptosis was absent at all doses in ced-3 and ced-4 loss-of-function strains. MC-LR-induced apoptosis was blocked in Bcl-2 gain-of-function strain ced-9(n1950), whereas it showed a slight increase in BH3-only protein EGL-1 mutated strain. The null mutation of cep-1, which is the homologue of p53 tumor suppressor gene, significantly inhibited MC-LR-induced cell death, and checkpoint proteins HUS-1 and CLK-2 exerted proapoptotic effects. Apoptosis in loss-of-function members of ERK, JNK, and p38 MAPK signaling pathways reduced significantly under MC-LR exposure, and members of MAPKK subgroup JKK-1, MEK-1, and SEK-1 worked cooperatively. Our results show that the caspase protein CED-3 and Apaf-1 protein CED-4 were absolutely required for the apoptotic processes, and that the p53/CEP-1 and MAPKs cascades played essential roles in modulating MC-LR-induced germline apoptosis in C. elegans.

Response of soil microorganisms to As-produced and functionalized single-wall carbon nanotubes (SWNTs).

The use of single-wall carbon nanotubes (SWNTs) in manufacturing and biomedical applications is increasing at a rapid rate; however data on the effects of a potential environmental release of the materials remain sparse. In this study, soils with either low or high organic matter contents as well as pure cultures of E. coli are challenged with either raw as-produced SWNTs (AP-SWNTs) or SWNTs functionalized with either polyethyleneglycol (PEG-SWNTs) or m-polyaminobenzene sulfonic acid (PABS-SWNTs). To mimic chronic exposure, the soil systems were challenged weekly for six weeks; microbial activities and community structures for both the prokaryote and eukaryote community were evaluated. Results show that repeated applications of AP-SWNTs can affect microbial community structures and induce minor changes in soil metabolic activity in the low organic matter systems. Toxicity of the three types of SWNTs was also assessed in liquid cultures using a bioluminescent E. coli-O157:H7 strain. Although decreases in light were detected in all treated samples, low light recovery following glucose addition in AP-SWNTs treatment and light absorption property of SWNTs particles suggest that AP-SWNTs suppressed metabolic activity of the E. coli, whereas the two functionalized SWNTs are less toxic. The metals released from the raw forms of SWNTs would not play a role in the effects seen in soil or the pure culture. We suggest that sorption to soil organic matter plays a controlling role in the soil microbiological responses to these nanomaterials.

Nutrient removal and energy production in a urine treatment process using magnesium ammonium phosphate precipitation and a microbial fuel cell technique.

Urine pretreatment has attracted increasing interest as it is able to relieve the nitrogen and phosphorus overloading problems in municipal wastewater treatment plants. In this study, an integrated process, which combines magnesium ammonium phosphate (MAP) precipitation with a microbial fuel cell (MFC), is proposed for the recovery of a slow-release fertilizer and electricity from urine. In such a two-step process, both nitrogen and phosphorus are recovered through the MAP process, and organic matters in the urine are converted into electricity in the MFCs. With this integrated process, when the phosphorus recovery is maximized without a dose of PO(4)(3-)-P in the MAP precipitation process, removal efficiencies for PO(4)(3)-P and NH(4)(+)-N of 94.6% and 28.6%, respectively, were achieved with a chemical oxygen demand (COD) of 64.9% accompanied by a power output of 2.6 W m(-3). Whereas removal efficiencies for PO(4)(3)-P and NH(4)(+)-N of 42.6% and 40%, respectively, and a COD of 62.4% and power density of 0.9 W m(-3) were obtained if simultaneous recovery of phosphorus and nitrogen was required through dosing with 620 mg L(-1) of PO(4)(3-)-P in the MAP process. This work provides a new sustainable approach for the efficient and cost-effective treatment of urine with the recovery of energy and resources.

Extracellular vesicle-packaged mitochondrial disturbing miRNA exacerbates cardiac injury during acute myocardial infarction.

Mounting evidence suggests that extracellular vesicles (EVs) are effective communicators in biological signalling in cardiac physiology and pathology. However, the role of EVs in cardiac injury, particularly in ischemic myocardial scenarios, has not been fully elucidated. Here, we report that acute myocardial infarction (AMI)-induced EVs can impair cardiomyocyte survival and exacerbate cardiac injury. EV-encapsulated miR-503, which is enriched during the early phase of AMI, is a critical molecule that mediates myocardial injury. Functional studies revealed that miR-503 promoted cardiomyocyte death by directly binding to peroxisome proliferator-activated receptor gamma coactivator-1ß (PGC-1ß) and a mitochondrial deacetylase, sirtuin 3 (SIRT3), thereby triggering mitochondrial metabolic dysfunction and cardiomyocyte death. Mechanistically, we identified endothelial cells as the primary source of miR-503 in EVs after AMI. Hypoxia induced rapid H3K4 methylation of the promoter of the methyltransferase-like 3 gene (METTL3) and resulted in its overexpression. METTL3 overexpression evokes N6-methyladenosine (m6 A)-dependent miR-503 biogenesis in endothelial cells. In summary, this study highlights a novel endogenous mechanism wherein EVs aggravate myocardial injury during the onset of AMI via endothelial cell-secreted miR-503 shuttling.

Integration of a microbial fuel cell with activated sludge process for energy-saving wastewater treatment: taking a sequencing batch reactor as an example.

In the research and application of microbial fuel cell (MFC), how to incorporate MFCs into current wastewater infrastructure is an importance issue. Here, we report a novel strategy of integrating an MFC into a sequencing batch reactor (SBR) to test the energy production and the chemical oxygen demand (COD) removal. The membrane-less biocathode MFC is integrated with the SBR to recover energy from the aeration in the form of electricity and thus reduce the SBR operation costs. In a lab-scale integrated SBR-MFC system, the maximum power production of the MFC was 2.34 W/m(3) for one typical cycle and the current density reached up to 14 A/m(3) . As a result, the MFC contributed to the 18.7% COD consumption of the integrated system and also recovered energy from the aeration tank with a volume fraction of only 12% of the SBR. Our strategy provides a feasible and effective energy-saving and -recovering solution to upgrade the existing activated sludge processes.

Enhanced reductive degradation of methyl orange in a microbial fuel cell through cathode modification with redox mediators.

A model azo dye, methyl orange (MO), was reduced through in situ utilization of the electrons derived from the anaerobic conversion of organics in a microbial fuel cell (MFC). The MO reduction process could be described by a pseudo first-order kinetic model with a rate constant of 1.29 day(-1). Electrochemical impedance spectroscopic analysis shows that the cathode had a high polarization resistance, which could decrease the reaction rate and limit the electron transfer. To improve the MO reduction efficiency, the cathode was modified with redox mediators to enhance the electron transfer. After modification with thionine, the polarization resistance significantly decreased by over 50%. As a consequence, the MO decolorization rate increased by over 20%, and the power density was enhanced by over three times. Compared with thionine, anthraquinone-2, 6-disulfonate modified cathode has less positive effect on the MFC performance. These results indicate that the electrode modification with thionine is a useful approach to accelerate the electrochemical reactions. This work provides useful information about the key factors limiting the azo dye reduction in the MFC and how to improve such a process.

Electricity generation from mixed volatile fatty acids using microbial fuel cells.

Fermentative hydrogen production, as a process for clean energy recovery from organic wastewater, is limited by its low hydrogen yield due to incomplete conversion of substrates, with most of the fermentation products being volatile fatty acids (VFAs). Thus, further recovery of the energy from VFAs is expected. In this work, microbial fuel cell (MFC) was applied to recover energy in the form of electricity from mixed VFAs of acetate, propionate, and butyrate. Response surface methodology was adopted to investigate the relative contribution and possible interactions of the three components of VFAs. A stable electricity generation was demonstrated in MFCs after the enrichment of electrochemically active bacteria. Analysis showed that power density was more sensitive to the composition of mixed VFAs than coulombic efficiency. The electricity generation could mainly be attributed to the portion of acetate and propionate. However, the two components showed an antagonistic effect when propionate exceeded 19%, causing a decrease in coulombic efficiency. Butyrate was found to exert a negative impact on both power density and coulombic efficiency. Denaturing gradient gel electrophoresis profiles revealed the enrichment of electrochemically active bacteria from the inoculum sludge. Proteobacteria (Beta-, Delta-) and Bacteroidetes were predominant in all VFA-fed MFCs. Shifts in bacterial community structures were observed when different compositions of VFA mixtures were used as the electron donor. The overall electron recovery efficiency may be increased from 15.7% to 27.4% if fermentative hydrogen production and MFC processes are integrated.

Isolation and characterization of a chlorate-reducing bacterium Ochrobactrum anthropi XM-1.

A Gram-negative chlorate-reducing bacterial strain XM-1 was isolated. The 16S rRNA gene sequence identified the isolate as Ochrobactrum anthropi XM-1, which was the first strain of genus Ochrobactrum reported having the ability to reduce chlorate. The optimum growth temperature and pH for strain XM-1 to reduce chlorate was found to be 30 °C and 5.0-7.5, respectively, under anaerobic condition. Strain XM-1 could tolerate high chlorate concentration (200 mM), and utilize a variety of carbohydrates (glucose, L-arabinose, D-fructose, sucrose), glycerin and sodium citrate as electron donors. In addition, oxygen and nitrate could be used as electron acceptors, but perchlorate could not be reduced. Enzyme activities related to chlorate reducing were characterized in cell extracts. Activities of chlorate reductase and chlorite dismutase could be detected in XM-1 cells grown under both aerobic and anaerobic conditions, implying the two enzymes were constitutively expressed. This work suggests a high potential of applying Ochrobactrum anthropi XM-1 for remediation of chlorate contamination.

Toxic effects of prolonged exposure to [C14mim]Br on Caenorhabditis elegans.

Ionic liquids (ILs) are gradually concerned due to their potential environmental and health risks. In this work, the chronic effects of imidazolium-based ILs, using [C14mim]Br as a representative, were evaluated using model animal Caenorhabditis elegans. Our results show that prolonged exposure (72 h) of ILs to the nematodes at concentrations of 5 and 10 mg/L induced adverse effects on the growth, locomotive behaviors and development. To explore the toxicity mechanism, lipofuscin content, ROS level and the expressions of five superoxide dismutase (SOD) genes were determined after the prolonged exposure. The lipofuscin content, ROS level and expressions of SOD genes did not show significant changes except that the expression of sod-5 was reduced by 2.7-fold following the treatment of 10 mg/L of [C14mim]Br. These results suggest that oxidative stress may not be responsible for the adverse physiological effects induced by relatively low concentrations of imidazolium-based ILs. We further determined the gene expressions of phase I detoxification enzyme cytochrome P450 (CYP), phase II detoxification enzyme UDP-glucuronosyltransferase (UGT) and ATP-binding cassette (ABC) transporter P-glycoprotein (PGP). The results demonstrate that CYP, UGT and PGP may be involved in the detoxification of ILs. Our findings will aid in understanding the mechanisms of both toxicity and detoxification of imidazolium-based ILs in animals.

Effective flocculation of Microcystis aeruginosa with simultaneous nutrient precipitation from hydrolyzed human urine.

Mechanical harvest of massive harmful algal blooms is an effective measure for bloom mitigation. Yet subsequent processing of the resulting water from algae water separation after the harvesting becomes a new problem since individual algal cells or small algal aggregates are still present in the water. Here, we proposed a novel approach for effectively flocculating the cyanobacteria Microcystis aeruginosa with a removal efficiency of 97% in 6 h using hydrolyzed urine. Nitrogen and phosphorus were simultaneously reclaimed through struvite formation. The addition of Mg2+ promoted the flocculation efficiency and nutrient removal as well as the yield of struvite. Ca2+ could enhance the flocculation efficiency by forming calcium phosphate. During the flocculation process, no significant damage in algal cells was observed. This study provides a novel and sustainable potential for subsequent processing of the resulting water after algae water separation with simultaneous nutrient precipitation and reducing nutrient loads to wastewater treatment plants.

Augmentation of acyl homoserine lactones-producing and -quenching bacterium into activated sludge for its granulation.

Quorum sensing (QS), especially acyl homoserine lactone (AHL)-mediated QS, in activated sludge arouses great interests because of its vital role in the formation of biofilm and aerobic granules (AG). Although QS is reported to be largely related to the properties of activated sludge, it is not economically feasible to tune QS in an activated sludge reactor through dosing pure AHL or AHL hydrolase. A more reasonable way to tune QS is to augment reactors with AHL-producing or -quenching bacteria. In this work, the impacts of continuous dose of AHL-producing or -quenching strains on the activated sludge during its granulation process were explored. Augmentation of AHL-producing or -quenching strains resulted in up- or down-regulation of the AHL concentration in the reactors. Granulation of activated sludge was also accomplished in all reactors, but the granules showed negligible or slight differences in the physicochemical properties of sludge, such as nutrients removal, biomass concentration, extracellular polymeric substances, and zeta potential. Interestingly, a smaller granule size was observed for both the reactor augmented with either an AHL-quenching strain or an AHL-producing strain, suggesting that the AHL augmentation suppressed the biofilm development. Pyrosequencing analysis reveals that the granules cultured in the reactors varied widely in bacterial community structure, indicating that the AHL augmentation had a greater impact on the bacterial community structure, rather than on the physicochemical properties of activated sludge. These results demonstrate that the role of QS in the biofilm formation in complex wastewater treatment bioreactors should be re-evaluated.