Mulberry Leaf Compounds and Gut Microbiota in Alzheimer's Disease and Diabetes: A Study Using Network Pharmacology, Molecular Dynamics Simulation, and Cellular Assays.

Recently, studies have reported a correlation that individuals with diabetes show an increased risk of developing Alzheimer's disease (AD). Mulberry leaves, serving as both a traditional medicinal herb and a food source, exhibit significant hypoglycemic and antioxidative properties. The flavonoid compounds in mulberry leaf offer therapeutic effects for relieving diabetic symptoms and providing neuroprotection. However, the mechanisms of this effect have not been fully elucidated. This investigation aimed to investigate the combined effects of specific mulberry leaf flavonoids (kaempferol, quercetin, rhamnocitrin, tetramethoxyluteolin, and norartocarpetin) on both type 2 diabetes mellitus (T2DM) and AD. Additionally, the role of the gut microbiota in these two diseases' treatment was studied. Using network pharmacology, we investigated the potential mechanisms of flavonoids in mulberry leaves, combined with gut microbiota, in combating AD and T2DM. In addition, we identified protein tyrosine phosphatase 1B (PTP1B) as a key target for kaempferol in these two diseases. Molecular docking and molecular dynamics simulations showed that kaempferol has the potential to inhibit PTP1B for indirect treatment of AD, which was proven by measuring the IC50 of kaempferol (279.23 µM). The cell experiment also confirmed the dose-dependent effect of kaempferol on the phosphorylation of total cellular protein in HepG2 cells. This research supports the concept of food-medicine homology and broadens the range of medical treatments for diabetes and AD, highlighting the prospect of integrating traditional herbal remedies with modern medical research.

A Novel Synthesized Cyclohexane-Hydroxytyrosol Derivative Suppresses Ovarian Cancer Cell Growth Through Inducing Reactive Oxidative Species and Blocking Autophagic Flux.

Aims: Drug resistance in ovarian cancer (OC) cells often leads to recurrence, metastasis, and high mortality rates among OC patients. Hydroxytyrosol (HT) has been reported to inhibit the proliferation of ovarian and other types of cancer cells. Here we synthesized a novel cyclohexane-hydroxytyrosol derivative (Chx-HT) for enhanced anticaner efficacy. We examined the growth-suppressing effect of Chx-HT on OC cells in vitro and in a xenograft mouse model and investigated the underlying mechanism. Results: We demonstrated that Chx-HT inhibits proliferation, promotes apoptosis, and remodels glucose and lipid metabolism by reducing fatty acid ß-oxidation while increasing glycolysis, de novo fatty acid synthesis (FAS), and lipid droplet (LD) accumulation, impairs mitochondrial respiration, and induces oxidative stress both in vitro and in vivo. In addition, Chx-HT blocks autophagic flux by obstructing the maturation of lysosomal cathepsins in the late stage, but also activates autophagy through the p-AMPK/p-mTOR/p-ULK1 pathway in response to energy deficit. Innovation and Conclusion: Reactive oxidative species (ROS) play a critical role in mediating the effects of Chx-HT on proliferation, apoptosis, autophagy, tricarboxylic acid (TCA) cycle, fatty acid ß-oxidation, and mitochondrial respiration, and the autophagic activation underlies the effects of Chx-HT on glycolysis, de novo FAS, and LD accumulation in OC cells. Cotreating OC cells with Chx-HT and autophagic inhibitor or glycolytic inhibitor results in an additive inhibition of proliferation. Our study indicates that Chx-HT stands for a promising OC therapeutic by ROS and autophagy blockade-mediated metabolic remodeling.

An approach to rapidly identify the gender of the pigeon by using cross-priming amplification with immune-chromatographic strip.

Most birds are monomorphic species and breeds, which makes it difficult to determine their gender by appearances, especially the pigeon is a farm animal with economic interest in meat production, ornamentals, sports, and experimental animals. Until now, the available methods for determining the gender of pigeons have mainly consisted of endoscopy, laparoscopy, karyotyping, polymerase chain reaction (PCR), and other similar techniques. Nonetheless, these methods have notable limitations, such as high expenses, invasiveness, and time-consuming procedures, which hinder their practicality for efficiently determining the gender of pigeons. Therefore, an easy, accurate, sensitive, on-site, affordable, and applicable rapid identification of the gender of the pigeon is widely needed for the owner of the pigeon. The purpose of this study was to develop and evaluate the efficacy of Cross-priming amplification (CPA) combined with an immune-chromatographic strip (CPA-strip) for gender identification of the pigeon. The methodology was optimized through various experimental trials. Subsequently, ten samples collected from pigeons were subjected to analysis using the optimized CPA-strip assay, and the results indicated that all female samples were accurately detected. In contrast, the blood samples collected from chickens and ducks were negative when tested with the CPA-strip assay. In conclusion, our study demonstrates the successful establishment of an immune-chromatographic CPA-strip assay for the on-site gender determination of pigeons with high accuracy.

Batch normalization followed by merging is powerful for phenotype prediction integrating multiple heterogeneous studies.

Heterogeneity in different genomic studies compromises the performance of machine learning models in cross-study phenotype predictions. Overcoming heterogeneity when incorporating different studies in terms of phenotype prediction is a challenging and critical step for developing machine learning algorithms with reproducible prediction performance on independent datasets. We investigated the best approaches to integrate different studies of the same type of omics data under a variety of different heterogeneities. We developed a comprehensive workflow to simulate a variety of different types of heterogeneity and evaluate the performances of different integration methods together with batch normalization by using ComBat. We also demonstrated the results through realistic applications on six colorectal cancer (CRC) metagenomic studies and six tuberculosis (TB) gene expression studies, respectively. We showed that heterogeneity in different genomic studies can markedly negatively impact the machine learning classifier's reproducibility. ComBat normalization improved the prediction performance of machine learning classifier when heterogeneous populations are present, and could successfully remove batch effects within the same population. We also showed that the machine learning classifier's prediction accuracy can be markedly decreased as the underlying disease model became more different in training and test populations. Comparing different merging and integration methods, we found that merging and integration methods can outperform each other in different scenarios. In the realistic applications, we observed that the prediction accuracy improved when applying ComBat normalization with merging or integration methods in both CRC and TB studies. We illustrated that batch normalization is essential for mitigating both population differences of different studies and batch effects. We also showed that both merging strategy and integration methods can achieve good performances when combined with batch normalization. In addition, we explored the potential of boosting phenotype prediction performance by rank aggregation methods and showed that rank aggregation methods had similar performance as other ensemble learning approaches.

Molecular Dynamics Simulations Combined with Markov Model to Explore the Effect of Allosteric Inhibitor Binding on Bromodomain-Containing Protein 4.

Bromodomain-Containing Protein 4 (BRD4) can play an important role in gene transcriptional regulation of tumor development and survival by participating in histone modification epigenetic mechanism. Although it has been reported that novel allosteric inhibitors such as ZL0590 have a high affinity with target protein BRD4 and good efficacy, their inhibitory mechanism has not been studied further. The aim of this study was to reveal the inhibition mechanism of allosteric inhibitor ZL0590 on Free-BRD4 and BRD4 binding MS436 (orthosteric inhibitor) by molecular dynamics simulation combined with a Markov model. Our results showed that BRD4-ZL0590 led to α-helices formation of 100-105 compared with Free-BRD4; the combination of MS436 caused residues 30-40 and 95-105 to form α-helices, while the combination of allosteric inhibitors untangled the α-helices formed by the MS436. The results of Markov flux analysis showed that the binding process of inhibitors mainly involved changes in the degree of α-helices at ZA loop. The binding of ZL0590 reduced the distance between ZA loop and BC loop, blocked the conformation at the active site, and inhibited the binding of MS436. After the allosteric inhibitor binding, the MS436 that could normally penetrate into the interior of the pocket was floating on the edge of the active pocket and did not continue to penetrate into the active pocket as expected. In summary, we provide a theoretical basis for the inhibition mechanism of ZL0590 against BRD4, which can be used as a reference for improving the development of drug targets for cancer therapy.

Fine particulate matter exposure disturbs autophagy, redox balance and mitochondrial homeostasis via JNK activation to inhibit proliferation and promote EMT in human alveolar epithelial A549 cells.

Epidemiologic studies have demonstrated a direct correlation between fine particulate matter (FPM) exposure and the high risk of respiratory diseases. FPM can penetrate deep into the lung and deposit in the alveoli with breath, where it directly interacts with alveolar epithelial cell (APC). However, we know little about the effects nor mechanisms of FPM on APC. Here, using human APC A549 cells, we found that FPM resulted in blockade of autophagic flux, redox imbalance and oxidative stress, mitochondrial fragmentation, increased mitophagy and impaired mitochondrial respiration. Further we showed that activation of JNK signaling (c-Jun N-terminal kinase) and excessive ROS (reactive oxygen species) release contribute to these adverse effects, with the former being upstream of the latter. More importantly, we found that scavenging ROS or inhibiting JNK activation could restore those effects as well as ameliorate FPM-induced inhibition of cell proliferation, and epithelial-mesenchymal transformation (EMT) in A549 cells. Taken together, our findings indicate that FPM leads to toxicity in alveolar type II cells via JNK activation, and JNK-targeting or antioxidant strategies might be beneficial for prevention or treatment of FPM-related pulmonary diseases.

α-Ketoglutarate Attenuates Hyperlipidemia-Induced Endothelial Damage by Activating the Erk-Nrf2 Signaling Pathway to Inhibit Oxidative Stress and Mitochondrial Dysfunction.

Aims: α-Ketoglutarate (AKG) is an intermediate of the tricarboxylic acid cycle and a key hub linking amino acid metabolism and glucose oxidation. Previous studies have shown that AKG improved cardiovascular diseases such as myocardial infarction and myocardial hypertrophy through antioxidant and lipid-lowering characteristics. However, its protective effect and mechanism on endothelial injury caused by hyperlipidemia have not been elucidated yet. In this study, we tested whether AKG possesses protective effects on hyperlipidemia-induced endothelial injury and studied the mechanism. Results: AKG administration both in vivo, and in vitro significantly suppressed the hyperlipidemia-induced endothelial damage, regulated ET-1 and nitric oxide levels, and reduced the inflammatory factor interleukin-6 and matrix metallopeptidase-1 by inhibiting oxidative stress and mitochondrial dysfunction. The protective effects were achieved by the mechanism of activating the Nrf2 phase II system through the ERK signaling pathway. Innovation: These results reveal the role of the AKG-ERK-Nrf2 signaling pathway in the prevention of hyperlipidemia-induced endothelial damage, and suggest that AKG, as a mitochondria-targeting nutrient, is a potential drug for the treatment of endothelial damage in hyperlipidemia. Conclusion: AKG ameliorated the hyperlipidemia-induced endothelial damage and inflammatory response by inhibiting oxidative stress and mitochondrial dysfunction. Antioxid. Redox Signal. 39, 777-793.

Hydrogen Protection Boosts the Bioactivity of Chrysanthemum morifolium Extract in Preventing Palmitate-Induced Endothelial Dysfunction by Restoring MFN2 and Alleviating Oxidative Stress in HAEC Cells.

As the most important natural antioxidants in plant extracts, polyphenols demonstrate versatile bioactivities and are susceptible to oxidation. The commonly used ultrasonic extraction often causes oxidation reactions involving the formation of free radicals. To minimize the oxidation effects during the ultrasonic extraction process, we designed a hydrogen (H2)-protected ultrasonic extraction method and used it in Chrysanthemum morifolium extraction. Hydrogen-protected extraction improved the total antioxidant capacity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and polyphenol content of Chrysanthemum morifolium water extract (CME) compared with air and nitrogen (N2) conditions. We further investigated the protective effects and mechanisms of CME on palmitate (PA)-induced endothelial dysfunction in human aorta endothelial cells (HAECs). We found that hydrogen-protected CME (H2-CME) best-prevented impairment in nitric oxide (NO) production, endothelial NO synthase (eNOS) protein level, oxidative stress, and mitochondrial dysfunction. In addition, H2-CME prevented PA-induced endothelial dysfunction by restoring mitofusin-2 (MFN2) levels and maintaining redox balance.

Computer-Aided Screening and Revealing Action Mechanism of Green Tea Polyphenols Intervention in Alzheimer's Disease.

The accumulation of cross-ß-sheet amyloid fibrils is a hallmark of the neurodegenerative process of Alzheimer's disease (AD). Although it has been reported that green tea substances such as epicatechin (EC), epicatechin-3-gallate (ECG), epigallocatechin (EGC) and epigallocatechin-3-gallate (EGCG) could alleviate the symptoms of AD and other neurodegenerative diseases, the pharmacological mechanism remains largely unexplored. This study aimed to reveal the underlying mechanism of EC, ECG, EGC and EGCG in AD using a computer-aided screening strategy. Our results showed that the four tea polyphenols interfered with the signaling pathways of AD via calcium signaling channels, neurodegeneration-multiple disease signal pathways and others. We also identified the key residues of the interaction between VEGFA and the four active components, which included Glu64 and Phe36. Overall, we have provided valuable insights into the molecular mechanism of tea polyphenols, which could be used as a reference to improve therapeutic strategies against AD.

Efficient Orange Emission in Mn2+-Doped Cs3Cd2Cl7 Perovskites with Excellent Stability.

Low-dimensional metal halides are attractive for applications in photodetectors, solid-state lighting, and solar cells, but poor stability is an obstacle that must be overcome in commercial applications. Herein, we successfully synthesized a Ruddlesden-Popper (RP)-phased perovskite Mn2+:Cs3Cd2Cl7 with high photoluminescence quantum yield (PLQY) and outstanding thermal and environmental stability by a solvothermal method. The pristine sample Cs3Cd2Cl7 exhibits a weak cyan broad emission centered at 510 nm with a low PLQY of ∼4%. Once Mn2+ ions are introduced into the host lattice, a bright orange emission peaking at 580 nm with a high PLQY of ∼74% was achieved, which is attributed to the efficient energy transfer from the host to Mn2+ ions and thus results in the 4T1 → 6A1 radiation transition of Mn2+ ions. The photoluminescence (PL) intensity and environmental stability of Mn2+:Cs3Cd2Cl7 can be further improved through A-site Rb alloying. Finally, an orange LED with outstanding color stability was fabricated on the basis of the Mn2+:Cs3Cd2Cl7. Our work successfully elucidates that dopant plays an integral role in tailoring optical properties.

A new LDH based sustained-release carbon source filter media to achieve advanced denitrogenation of low C/N wastewater at low temperature.

Advanced denitrogenation of wastewater is now facing major challenges brought by low C/N ratio and low temperature. The development of sustained-release materials with good and stable carbon release properties was an effective countermeasure. FeNi-Layered double-metal hydroxides (LDH)- sodium carboxymethyl cellulose (CMC) filter media and its potential use in heterotrophic and sulfur-based mixotrophic denitrification biological filter (DNBF), was firstly reported. It demonstrated stable structure and good carbon release performance with a mass transfer coefficient (K) of 4.40 mg·L-1·s-1. When the influent NO3--N of 50 mg/L with the C/N ratio of 3 at 10 °C, the maximum nitrogen loading rate of 0.22 kg·N/(m3·d) and effluent TN close to 5 mg/L (nitrogen removal of almost 90 %) could be achieved. The slowly released carbon source and the leached iron increased the abundance of denitrifying bacteria and functional genes, and the augmentation of Sulfuritalea and the secretion of biofilm protein stimulated by sulfur also played a synergistic role. This study provided a new potentially effective strategy to enhance advanced denitrification of wastewater of low C/N wastewater at low temperature.

Phase-Selective Solution Synthesis of Cd-Based Perovskite Derivatives and Their Structure/Emission Modulation.

The rich phase structures of perovskite derivatives have attracted extensive attention and can be applied in the fields of optoelectronics due to their high emission efficiency and tunable emission. Herein, we explored a phase-selective solution synthetic route to obtain different Cd-based perovskite derivatives. First, the pristine tetragonal Cs7Cd3Br13 was obtained by a solvothermal method, and its photoluminescence quantum yield (PLQY) was boosted from 8.28% to 57.62% after appropriate Sb3+ doping. Furthermore, halogen substitution was adopted to modify Sb:Cs7Cd3Br13 and produced a series of Cd-based perovskite derivatives with different crystal structures and tunable emission from cyan to orange (517-625 nm). The mechanisms behind such experimental phenomena were further investigated and discussed on the basis of material characterization and theoretical computation. This study presented an effective strategy to synthesize bright Cd-based perovskite derivatives with different structures and modulated emission, and it also provided insights to understand the structure/emission modulation via halogen substitution.

Increasing prediction performance of colorectal cancer disease status using random forests classification based on metagenomic shotgun sequencing data.

Dysfunction of microbial communities in various human body sites has been shown to be associated with a variety of diseases raising the possibility of predicting diseases based on metagenomic samples. Although many studies have investigated this problem, there are no consensus on the optimal approaches for predicting disease status based on metagenomic samples. Using six human gut metagenomic datasets consisting of large numbers of colorectal cancer patients and healthy controls from different countries, we investigated different software packages for extracting relative abundances of known microbial genomes and for integrating mapping and assembly approaches to obtain the relative abundance profiles of both known and novel genomes. The random forests (RF) classification algorithm was then used to predict colorectal cancer status based on the microbial relative abundance profiles. Based on within data cross-validation and cross-dataset prediction, we show that the RF prediction performance using the microbial relative abundance profiles estimated by Centrifuge is generally higher than that using the microbial relative abundance profiles estimated by MetaPhlAn2 and Bracken. We also develop a novel method to integrate the relative abundance profiles of both known and novel microbial organisms to further increase the prediction performance for colorectal cancer from metagenomes.

Component Engineering to Tailor the Structure and Optical Properties of Sb-Doped Indium-Based Halides.

Controlling the structure of halide perovskites through component engineering, and thus revealing the changes in luminescence properties caused by the conversion of crystal structure, is of great significance. Herein, we report a controllable synthetic strategy of three-dimensional (3D) Cs2KInCl6 and zero-dimensional (0D) (Cs/K)2InCl5(H2O) halide perovskites by changing the Cs/K feed ratio. 3D Cs2KInCl6 double perovskites are obtained at the Cs/K feed ratio of 1:1, while 0D (Cs/K)2InCl5(H2O) perovskites are formed at the Cs/K feed ratio of 2:1. Further, a reversible crystal structure transformation between 3D Cs2KInCl6 double perovskites and 0D (Cs/K)2InCl5(H2O) perovskites can be achieved by subsequent addition of metal-salt precursors. In addition, the emission efficiency of two perovskite structures can be greatly boosted by breaking the forbidden transition through Sb doping, and as a result, a novel green/yellow reversible emission switch is generated. Meanwhile, the relationship between perovskite structure and luminescence mechanism has been systematically revealed. These environmentally stable halide perovskites have great potential to be applied in optoelectronic devices.

Amylin deposition activates HIF1α and 6-phosphofructo-2-kinase/fructose-2, 6-biphosphatase 3 (PFKFB3) signaling in failing hearts of non-human primates.

Hyperamylinemia induces amylin aggregation and toxicity in the pancreas and contributes to the development of type-2 diabetes (T2D). Cardiac amylin deposition in patients with obesity and T2D was found to accelerate heart dysfunction. Non-human primates (NHPs) have similar genetic, metabolic, and cardiovascular processes as humans. However, the underlying mechanisms of cardiac amylin in NHPs, particularly related to the hypoxia inducible factor (HIF)1α and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) signaling pathways, are unknown. Here, we demonstrate that in NHPs, amylin deposition in heart failure (HF) contributes to cardiac dysfunction via activation of HIF1α and PFKFB3 signaling. This was confirmed in two in vitro cardiomyocyte models. Furthermore, alterations of intracellular Ca2+, reactive oxygen species, mitochondrial function, and lactate levels were observed in amylin-treated cells. Our study demonstrates a pathological role for amylin in the activation of HIF1α and PFKFB3 signaling in NHPs with HF, establishing amylin as a promising target for heart disease patients.

Simultaneous nitrogen removal and toxicity reduction of synthetic municipal wastewater by micro-electrolysis and sulfur-based denitrification biofilter.

Simultaneous nitrogen removal and toxicity reduction are critical for safe reuse of wastewater, but research in this area is limited. In this study, micro-electrolysis and sulfur-based denitrification biofilters (DNBFs) were applied for simultaneous nitrogen removal and toxicity reduction for municipal wastewater. When COD was 250 ± 1 mg/L, NO3--N was 50 ± 1 mg/L, total nitrogen (TN) of effluent was below 5 mg/L with the nitrogen load of 0.149 kg N/(m3·d) in all the reactors, while the effect of electrolysis on TN removal was not obvious. Micro-electrolysis promoted toxicity reduction by 8.7-17.4% only in sulfur-based DNBFs, and it also increased biofilm PN/PS by 7.56-43.46% and enhanced Cloacibacterium's abundance responsible for toxicity reduction (p < 0.05). Introduction of sulfur resulted in the contribution of sulfur-based autotrophic denitrification up to 21.48% and Sulfurimonas mainly contributed to toxicity reduction (p < 0.05).

Does electrolysis facilitate simultaneous nitrogen removal and toxicity reduction of low C/N dyeing wastewater by sulfur-based denitrification biofilter?

The concern about wastewater effluent toxicity has motivated the innovation of enhancement technologies on sulfur-based denitrification biofilter in recent years. Electrolysis is a common technology to reduce or remove toxic pollutants. However, the effect of electrolysis on simultaneous total nitrogen (TN) removal and toxicity reduction in sulfur-based denitrification biofilter has not been reported yet. Herein, for the first time, this study investigated the synergistic effects of electrolysis-induced TN removal and toxicity reduction of secondary effluent of dyeing wastewater containing 20 µg/L of nonylphenol (NP), at different carbon to nitrogen ratios (C/N) in several sulfur-based denitrification biofilters. All of the biofilters achieved the denitrification rate of 300.15 g∙N/m3∙d during the stabilization period at C/N = 5. The CSAHD (ceramisite and sulfur as filters) biofilter had highest TN removal rate to achieve the denitrification rate of 257.46 g∙N/m3·d at C/N = 2. Siderite and dolomite both facilitated TN removal efficiency by 9.3%-12.6% under low C/N ratio and acted as the buffer agent in biofilters. Toxicity characteristic leaching procedure (TCLP) test showed that the amount of leached heavy metals was lower than the concentration limit standard of USEPA. Electrolysis did not promote the removal of TN, however, it could reduce NP concentration and increase the biotoxicity relative inhibition rate of effluent by 12.5%-167%, and affect the functional microbial community structure. Our work clarified some misunderstandings about the application of electrolysis-based strengthening technology and enlightened the future development of simultaneous TN removal and toxicity reduction of dyeing wastewater.

A novel start-up strategy for mixotrophic denitrification biofilters by rhamnolipid and its performance on denitrification of low C/N wastewater.

A novel start-up strategy for sulfur-based mixotrophic denitrification biofilters (mDNBFs) by rhamnolipid was investigated for the first time. Rhamnolipid with gradient concentrations (0-120 mg/L) was added into five lab-scale mDNBFs. Results showed that rhamnolipid could promote biomass yield and nitrogen removal rate (NRR) by 71.7% and 68.7%, respectively, while its effect on EPS and adhesion force was concentration-dependent. The spatial distribution characteristics of microbial communities demonstrated the enrichment of main heterotrophic denitrifying bacteria outcompeted that of the autotrophs, with a more pronounced difference in high concentration rhamnolipid-treated mDNBFs. Furthermore, highest abundance of napA, narG, nirK and nosZ genes was observed in 80 mg/L rhamnolipid-treated mDNBF. Interfacial processes including solubilizing effect and hydration repulse and variations of organics were discussed to explicate the underlying mechanism. The study enlightened that an appropriate concentration (∼80 mg/L) of rhamnolipid may be a good solution for accelerating biofilm formation and enriching denitrifying bacteria to promote denitrification performance of mDNBFs treating low C/N wastewater.

Undesirable effects of exogenous N-acyl homoserine lactones on moving bed biofilm reactor treating medium-strength synthetic wastewater.

Exogenous AHLs are gradually reported to facilitate biofilm growth, however, whether they play a universal role in promoting biofilm formation and pollutants removal remains to be investigated. The pollutant removal, biofilm properties, microbial community and the distribution of AHLs were investigated in three lab-scale MBBRs by continuous dosing 100 nM N-Hexanoyl-L-homoserine lactone (C6-HSL) and N-Octanoyl-L-homoserine lactone (C8-HSL) in synthetic wastewater under normal nutrition (40 mg/L NH4+-N with C/N = 20). Results showed that adding AHLs didn't affect organics removal and exogenous C6-HSL even significantly suppressed NH4+-N removal by 0.44-20.29% after 16 days (p < 0.05). The introduction of AHLs both facilitated biofilm growth and extracellular polymeric substances secretion while suppressed ATP production especially during the stable operation period, with 48.96% by C6-HSL (p < 0.05) and 27.25% by C8-HSL, respectively. Exogenous AHLs inhibited the proliferation of Chryseobacterium, resulting in improvement in biofilm growth and it probably mediated ATP synthesis through regulating the release of 3OHC12-HSL in aqueous phase. Organics removal and biofilm growth were mainly attributed to the combined actions of multitudinous AHLs in biofilm phase rather than that in aqueous phase. The counterintuitive conclusions obtained in this study highlighted the importance of legitimately applying exogenous AHLs to accelerate biofilm formation and the start-up of MBBR in wastewater treatment.

Enhanced biofilm formation and denitrification in biofilters for advanced nitrogen removal by rhamnolipid addition.

Denitrification biofilters (DNBFs) are widely used in advanced nitrogen removal of wastewater with low C/N and effective biofilm formation is critical to their long-term operation. Hereby the influence of rhamnolipid addition in DNBFs was investigated for the first time. Gradient concentrations (0, 20, 40, 80, 120 mg/L) of rhamnolipid were applied to investigate nitrogen removal, biofilm properties and microbial community of lab-scale DNBFs. A significant increase of nitrogen removal was observed in rhamnolipid-treated DNBFs (p < 0.05). Total solid (TS), extracellular polymeric substances (EPS) and adhesion force of biofilms in DNBF with 120 mg/L rhamnolipid reached the maximum, which were 2.17, 2.15 and 3.36 times of those in the control, respectively. Moreover, rhamnolipid exhibited an improvement in abundance of Simplicispira and Gemmatimonas which were responsible for enhanced biofilm formation and denitrification. The results suggested that rhamnolipid addition can be a novel strategy to improve the start-up and denitrification performance of DNBFs.