Exploring the effective compounds and potential mechanisms of Shengxian Decoction against coronary heart disease by UPLC-Q-TOF/MS and network pharmacology analysis.

As a well-known classical Chinese medicine prescription, Shengxian Decoction (SXD) has been applied for a century to treat cardiovascular diseases, especially coronary heart disease (CHD), but the potentially effective compounds and underlying mechanisms remain unclear. With ultra-performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF/MS) and network pharmacology analysis, the potential effective compounds of SXD and their pharmacological mechanisms against CHD were identified and revealed. 57 effective compounds with favorable pharmacokinetic characteristics and biological activities were screened through UPLC-Q-TOF/MS analysis, database and literature mining, interacting with 96 CHD-related targets to support potential synergistic therapeutic actions. Systematic analysis of the PPI network and microarray data further revealed six core targets, including TNF, IL-1ß, IL-6, TP53, VEGFA and PTGS2, which were mainly involved in fluid shear stress and atherosclerosis, lipid and atherosclerosis, PI3K-Akt signaling pathway et al. Moreover, the proposed contribution indexes of effective compounds indicated these compounds, including isoferulic acid, quercetin, calycosin, ferulic acid, kaempferol, calycosin 7-O-glycoside, formononetin, astragaloside IV and saikosaponin D, as the core compounds of SXD. The molecular docking results confirmed that those core compound-target pairs exhibited strong binding energy. Furthermore, we validated that SXD significantly alleviated myocardial tissue injury in CHD rats and reversed H/R-induced decreases in H9c2 cell viability by attenuating the production of TNF, IL-6 and IL-1ß, and reducing cardiomyocyte apoptosis via down-regulating the TP53, caspase3 and cytochrome C mRNA expression levels as well as caspase3, caspase9 and cytochrome C protein expression levels according to RT-qPCR and Western blot results. Our findings explained the pharmacological mechanisms underlying the effectiveness of SXD in the treatment of CHD, and laid a foundation for future basic and clinical research of SXD.

The identification of metabolites from gut microbiota in coronary heart disease via network pharmacology.

Although the gut microbial metabolites exhibit potential effects on coronary heart disease (CHD), the underlying mechanism remains unclear. In this study, the active gut microbial metabolites acting on CHD and their potential mechanisms of action were explored through a network pharmacological approach. We collected a total of 208 metabolites from the gutMgene database and 726 overlapping targets from the similarity ensemble approach (SEA) and SwissTargetPrediction (STP) database, and ultimately identified 610 targets relevant to CHD. In conjunction with the gutMGene database, we identified 12 key targets. The targets of exogenous substances were removed, and 10 core targets involved in CHD were eventually retained. The microbiota-metabolites-targets-signalling pathways network analysis revealed that C-type lectin receptor signalling pathway, Lachnospiraceae, Escherichia, mitogen-activated protein kinase 1, prostaglandin-endoperoxidase synthase 2, phenylacetylglutamine and alcoholic acid are notable components of CHD and play important roles in the development of CHD. The results of molecular docking experiments demonstrated that AKT1-glycocholic acid and PTGS2-phenylacetylglutamine complexes may act on C-type lectin receptor signalling pathways. In this study, the key substances and potential mechanisms of gut microbial metabolites were analysed via network pharmacological methods, and a scientific basis and comprehensive idea were provided for the effects of gut microbial metabolites on CHD.

Differential regulation of hair cell actin cytoskeleton mediated by SRF and MRTFB.

The MRTF-SRF pathway has been extensively studied for its crucial role in driving the expression of a large number of genes involved in actin cytoskeleton of various cell types. However, the specific contribution of MRTF-SRF in hair cells remains unknown. In this study, we showed that hair cell-specific deletion of Srf or Mrtfb, but not Mrtfa, leads to similar defects in the development of stereocilia dimensions and the maintenance of cuticular plate integrity. We used fluorescence-activated cell sorting-based hair cell RNA-Seq analysis to investigate the mechanistic underpinnings of the changes observed in Srf and Mrtfb mutants, respectively. Interestingly, the transcriptome analysis revealed distinct profiles of genes regulated by Srf and Mrtfb, suggesting different transcriptional regulation mechanisms of actin cytoskeleton activities mediated by Srf and Mrtfb. Exogenous delivery of calponin 2 using Adeno-associated virus transduction in Srf mutants partially rescued the impairments of stereocilia dimensions and the F-actin intensity of cuticular plate, suggesting the involvement of Cnn2, as an Srf downstream target, in regulating the hair bundle morphology and cuticular plate actin cytoskeleton organization. Our study uncovers, for the first time, the unexpected differential transcriptional regulation of actin cytoskeleton mediated by Srf and Mrtfb in hair cells, and also demonstrates the critical role of SRF-CNN2 in modulating actin dynamics of the stereocilia and cuticular plate, providing new insights into the molecular mechanism underlying hair cell development and maintenance.

Anti-obesity and Gut Microbiota Modulation Effect of Astragalus Polysaccharides Combined with Berberine on High-Fat Diet-Fed Obese Mice.

OBJECTIVE: To investigate whether astragalus polysaccharides (APS) combined with berberine (BBR) can reduce high-fat diet (HFD)-induced obesity in mice. METHODS: Except for normal mice, 32 HFD-induced obese mice were randomized into HFD, APS (1,000 mg/kg APS), BBR (200 mg/kg BBR), and APS plus BBR (1,000 mg/kg APS plus 200 mg/kg BBR) groups, respectively. After 6-week treatment (once daily by gavage), the obesity phenotype and pharmacodynamic effects were evaluated by histopathological examination of epididymal fat, liver, and colon using hematoxylin-eosin staining and serum biochemical analyses by an automated chemistry analyzer. The feces were collected at the 12 th week, and taxonomic and functional profiles of gut microbiota were analyzed by 16S ribosomal ribonucleic acid (16S rRNA) sequencing. RESULTS: Compared with HFD group, the average body weight of APS plus BBR group was decreased (P<0.01), accompanied with the reduced fat accumulation, enhanced colonic integrity, insulin sensitivity and glucose homeostasis (P<0.05 or P<0.01). Importantly, APS combined with BBR treatment was more effective than APS or BBR alone in improving HFD-induced insulin resistance (P<0.05 or P<0.01). 16S rRNA sequence-based analysis of fecal samples demonstrated that APS combined with BBR treatment exhibited a better impact on HFD-induced gut microbiota dysbiosis, exclusively via the enriched abundances of Bacteroides, which corresponded to the large increase of predicted bacterial genes involved in carbohydrate metabolism. CONCLUSION: APS combined with BBR may synergistically reduce obesity and modulate the gut microbiota in HFD-fed mice.

CST1 promotes the proliferation and migration of PDGF-BB-treated airway smooth muscle cells via the PI3K/AKT signaling pathway.

Typically, airway remodeling caused by migration and proliferation of airway smooth muscle cells (ASMCs) plays a crucial role in the pathophysiological characteristics of asthma development. Cystatin 1 (CST1), a protein-coding gene referred to as Cystatin SN, is highly expressed in asthma patients. However, the role of CST1 and related molecular mechanisms in the development of asthma remains to be explored. This study aims to investigate the role of CST1 in asthma progression and present related molecular mechanisms. To explore these aspects, human ASMCs with platelet-derived growth factor BB (PDGF-BB) are initially stimulated and applied as a cellular model of asthma. Further, CST1 is knocked down with small interfering ribose nucleic acid (siRNA) overexpressed with plasmids. Then, 5-ethynyl-2'-deoxyuridine (EdU) and Cell Count Kit (CCK)-8 assays are applied to assess the cell proliferation rates. Further, Transwell and Western blot analyses for migration of cells and expression of MMP1 and MMP9 proteins are assessed, respectively. Under PDGF-BB stimulation, human ASMCs showed an increased CST1 expression, enhanced proliferation, and migration abilities, as well as up-regulated PI3K/AKT signaling pathway. Further, knockdown or overexpression of CST1 presented the declined or enhanced proliferation, migration, and up-regulation of the PI3K/AKT signaling pathway of human ASMCs. Inhibiting PI3K/AKT signaling pathway displayed the reduced migration and proliferation of human ASMCs. In summary, these findings indicated that CST1 played an essential role in the progression of asthma by activating the PI3K/AKT signaling pathway and promoting the migration and proliferation abilities of human ASMCs treated with PDGF-BB.

New Alloy of an Al-Chalcogen System: AlSe Surface Alloys on Al(111).

Metal chalcogenides are a promising material for novel physical research and nanoelectronic device applications. Here, we systematically investigate the crystal structure and electronic properties of AlSe alloys on Al(111) using scanning tunneling microscopy, angle-resolved photoelectron spectrometry, and first-principle calculations. We reveal that the AlSe surface alloy possesses a closed-packed atomic structure. The AlSe surface alloy comprises two atomic sublayers (Se sublayer and Al sublayer) with a height difference of 1.16 Å. Our results indicate that the AlSe alloy hosts two hole-like bands, which are mainly derived from the in-plane orbital of AlSe (p x and p y ). These two bands located at about -2.22 ±0.01 eV around the Gamma point, far below the Fermi level, distinguished from other metal chalcogenides and binary alloys. AlSe alloys have the advantages of large-scale atomic flat terraces and a wide band gap, appropriate to serve as an interface layer for two-dimensional materials. Meanwhile, our results provide implications for related Al-chalcogen interfaces.

Methodology of network pharmacology for research on Chinese herbal medicine against COVID-19: A review.

Traditional Chinese medicine, as a complementary and alternative medicine, has been practiced for thousands of years in China and possesses remarkable clinical efficacy. Thus, systematic analysis and examination of the mechanistic links between Chinese herbal medicine (CHM) and the complex human body can benefit contemporary understandings by carrying out qualitative and quantitative analysis. With increasing attention, the approach of network pharmacology has begun to unveil the mystery of CHM by constructing the heterogeneous network relationship of "herb-compound-target-pathway," which corresponds to the holistic mechanisms of CHM. By integrating computational techniques into network pharmacology, the efficiency and accuracy of active compound screening and target fishing have been improved at an unprecedented pace. This review dissects the core innovations to the network pharmacology approach that were developed in the years since 2015 and highlights how this tool has been applied to understanding the coronavirus disease 2019 and refining the clinical use of CHM to combat it.

Intensive vs non-intensive statin pretreatment before percutaneous coronary intervention in Chinese patients: A meta-analysis of randomized controlled trials.

BACKGROUND: The results of intensive statin pretreatment before percutaneous coronary intervention (PCI) is inconsistent between Chinese and Western populations, and there are no corresponding meta-analyses involving hard clinical endpoints in the available published literature. AIM: To evaluate the efficacy and safety of high-dose statin loading before PCI in Chinese patients through a meta-analysis. METHODS: Relevant studies were identified by searching the electronic databases of PubMed, Embase and Cochrane's Library to December 2019. The outcomes included an assessment of major adverse cardiovascular event (MACE), non-fatal myocardial infarction (MI), cardiac death, target vessel revascularization (TVR), myalgia /myasthenia and abnormal alanine aminotransferase (ALT) in all enrolled patients. Random effect model and fixed effect model were applied to combine the data, which were further analyzed by χ 2 test and I 2 test. The main outcomes were then analyzed through the use of relative risks (RR) and its 95% confidence interval (95%CI). RESULTS: Eleven studies involving 3123 individuals were included. Compared with patients receiving placebo or no statin treatment before surgery, intensive statin treatment was associated with a clear reduction of risk of MACE (RR = 0.44, 95%CI: 0.31-0.61, P < 0.00001). However, compared with the patients receiving moderate-intensity statin before surgery, no advantage to intensive statin treatment was seen (RR = 1.04, 95%CI: 0.82-1.31, P = 0.74). In addition, no significant difference was observed between intensive statin therapy and non-intensive statin therapy on the incidence of TVR (RR = 0.43, 95%CI: 0.18-1.02, P = 0.06) , myalgia /myasthenia (RR = 1.35, 95%CI: 0.30-5.95, P = 0.69) and abnormal alanine aminotransferase (RR = 1.47, 95%CI: 0.54-4.02, P = 0.45) except non-fatal MI (RR = 0.54, 95%CI: 0.33-0.88, P = 0.01). CONCLUSION: Compared with placebo or no statin pretreatment, intensive statin before PCI displayed reduced incidence of MACE. However, there was no significant benefit between high and moderate-intensity statin. In addition, no significant difference was observed between intensive statin therapy and non-intensive statin therapy on the incidence of TVR, myalgia/myasthenia and abnormal alanine aminotransferase except non-fatal MI.

The relationship between activity level and cognitive function in Chinese community-dwelling elderly.

To study the relationship between daily activity level and cognitive function in community-dwelling elderly. We collected demographic features, cognitive function, activity level and self-rating depression scale scores in 53 community-dwelling olderly aged 60 years or above. The activity level and moderate-to-vigorous physical activity (MVPA) time were assessed by using the accelerometer for 7 consecutive days. We compared activity level, MVPA time and depression scores between cognitive impaired and normal groups. Cognitive functions were compared in groups with different MVPA level, and the correlation between cognitive function and MVPA time was analysed. Of the 53 subjects, 27 had varying degrees of cognitive impairment. Individuals with cognitive impairment shown significantly shorter MVPA time and higher depression score compared to the cognitive normal group (P < 0.05). After controlling for confounding factors (age, BMI), MVPA time was associated with cognitive function (r = 0.358, P = 0.009). The memory factor score correlated with MVPA time (r = 0.357, P = 0.012) and mean activity level (r = 0.287, P = 0.046). Moderate-to-vigorous physical activity in the elderly was positively related to their cognitive function. Strengthening daily activities may beneficial for the elderly to maintain better cognitive function.

Network Pharmacology-Based Dissection of the Active Ingredients and Protective Mechanism of the Salvia Miltiorrhiza and Panax Notoginseng Herb Pair against Insulin Resistance.

The Salvia miltiorrhiza and Panax notoginseng herb pair (DQ) has been widely utilized in traditional Chinese medicine for the longevity and for preventing and treating cardio-cerebrovascular diseases. Often associated with cardio-cerebrovascular diseases are comorbidities such as insulin resistance. However, the protective mechanisms of DQ against insulin resistance remain not well understood. Through network pharmacology analysis, a total of 94 candidate active compounds selected from DQ (61 from S. miltiorrhiza Bunge and 33 from P. notoginseng (Burk.) F. H. Chen) interacted with 52 corresponding insulin resistance-related targets, which mainly involved insulin resistance and the AMPK signaling pathway. Furthermore, the contribution index calculation results indicated 25 compounds as the principal components of this herb pair against insulin resistance. Among them, ginsenoside F2, protocatechuic acid, and salvianolic acid B were selected and validated to promote glucose consumption through activating AMPK phosphorylation and upregulating GLUT4 in insulin-resistant cell model (HepG2/IR) cells. These findings indicated that DQ has the potential for repositioning in the treatment of insulin resistance mainly through the AMPK signaling pathway.

[Research progress on processing history evolution as well as effect on chemical compositions and traditional pharmacological effects of Rhei Radix et Rhizoma].

Rhei Radix et Rhizoma(RRR) is a commonly used traditional Chinese medicine, with extensive pharmacological effects and clinical applications. This paper summarized processing history evolution of RRR and its effect on chemical compositions and pharmacological effects, and provided feasible insights for further studies on the chemical compositions and pharmacological effects of RRR before and after processing. Relevant information demonstrated that RRR has a long history of processing and various methods. At pre-sent, Chinese Pharmacopoeia mainly records four processing methods: cleaning(raw RRR), wine processing(RRR stir-fried with wine), steaming processing(RRR wine steaming), fried charcoal(RRR charring). RRR has a good effect in clearing heat effect, hemostatic effect and blood promoting effect, and its main chemical components are anthraquinone/anthrones, stilbene, phenylbutanone, chromogens, flavonoids and tannin compounds. This paper reviewed the history evolution of RRR and its effect on chemical composition and pharmacological changes, and put forward further study ideas, with the aim to provide a basic reference for processing mechanism, effective material basis and clinical application of RRR.

Quantitative evaluation of Danqi tablet by ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry integrated with bioassay.

Danqi tablet composed of the dried roots of Salvia miltiorrhiza and Panax notoginseng is a well-known Chinese patent medicine commonly used for the treatment of cardio-cerebrovascular diseases such as coronary heart disease and myocardial ischemia. Numerous chemical constituents belonging to S. miltiorrhiza and P. notoginseng were detectable in Danqi tablet. Here, we established and validated a rapid and sensitive ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry method for simultaneous quantification of 23 components in Danqi tablet and then successfully applied to assay 12 batches of samples from ten manufacturers. Our results demonstrated that the contents of 23 components in 12 batches of Danqi tablets varied significantly and their quality indeed existed differently based on the principal component analysis. According to the quantitative data and the loading plot of principal component analysis, five abundant compounds in Danqi tablet were selected as characteristic chemical markers possibly responsible for the quality assessment. Among them, salvianolic acid B and ginsenoside Rg1 were further chosen to be combined at 2:5 ratio to evaluate the anti-thrombotic activity on phenylhydrazine-induced zebrafish heart thrombosis model. Expectedly, this component combination increased the heart red blood cells intensity compared with the model group and the median effective concentration was 123.4 µg/mL, suggestive of its well anti-thrombotic effect. This study contributed to the quantitative evaluation of Danqi tablet and indicated the combination of salvianolic acid B and ginsenoside Rg1 may be capable of reflecting the effect of Danqi tablet, thereby providing a reference for further investigations on the improvement of quality control and clinical application of Danqi tablet.

Drug repurposing for COVID-19: could vitamin C combined with glycyrrhizic acid be at play by the findings of Li et al.'s database-based network pharmacology analysis?

The outbreak and pandemic of SARS-CoV-2 in 2019 has caused a severe public health burden and will challenge global health for the future. The discovery and mechanistic investigation of drugs against Coronavirus disease 2019 (COVID-19) is in deadly demand. The paper published by Li and colleagues proposed the hypothesis that vitamin C combined with glycyrrhizic acid in treating COVID-19 and its mechanistic investigation was performed by a database-based network pharmacology. In this letter, we present critical comments on the limitations and insufficiencies involved, from both the perspective of network pharmacology and current evidence on COVID-19.

Therapeutic Potential of Hydroxysafflor Yellow A on Cardio-Cerebrovascular Diseases.

The incidence rate of cardio-cerebrovascular diseases (CCVDs) is increasing worldwide, causing an increasingly serious public health burden. The pursuit of new promising treatment options is thus becoming a pressing issue. Hydroxysafflor yellow A (HSYA) is one of the main active quinochalcone C-glycosides in the florets of Carthamus tinctorius L., a medical and edible dual-purpose plant. HSYA has attracted much interest for its pharmacological actions in treating and/or managing CCVDs, such as myocardial and cerebral ischemia, hypertension, atherosclerosis, vascular dementia, and traumatic brain injury, in massive preclinical studies. In this review, we briefly summarized the mode and mechanism of action of HSYA on CCVDs based on these preclinical studies. The therapeutic effects of HSYA against CCVDs were presumed to reside mostly in its antioxidant, anti-inflammatory, and neuroprotective roles by acting on complex signaling pathways.

Gut microbiota modulation with traditional Chinese medicine: A system biology-driven approach.

With the development of system biology, traditional Chinese medicine (TCM) is drawing more and more attention nowadays. However, there are still many enigmas behind this ancient medical system because of the arcane theory and complex mechanism of actions. In recent decades, advancements in genome sequencing technologies, bioinformatics and culturomics have led to the groundbreaking characterization of the gut microbiota, a 'forgotten organ', and its role in host health and disease. Notably, gut microbiota has been emerging as a new avenue to understanding TCM. In this review, we will focus on the structure, composition, functionality and metabolites of gut microbiota affected by TCM so as to conversely understand its theory and mechanisms. We will also discuss the potential areas of gut microbiota for exploring Chinese material medica waste, Chinese marine material medica, add-on therapy and personalized precise medication of TCM. The review will conclude with future perspectives and challenges of gut microbiota in TCM intervention.

Berberine treatment-emergent mild diarrhea associated with gut microbiota dysbiosis.

Berberine (BBR) is a non-prescription drug to treat various bacteria-associated diarrheas. However, BBR has also been reported to cause diarrhea in clinic, with underlying mechanisms poorly understood. Because altered gut microbial ecology is a potential basis for diarrhea, this study was conducted to investigate the impact of BBR on gut microbiota of treatment-emergent diarrhea. BBR treatment (200 mg/kg, i.g.) in normal rats exhibited no significant changes in serum biochemical parameters but mild diarrhea occurred, accompanied with the decreased gastrointestinal transit time and increased fecal moisture, suggestive of the local effects of BBR in the intestine. Colon histology revealed the decreased abundance of mucus-filled goblet cells in BBR group. Although BBR-treated rats had the enlarged cecum with watery caecal digesta, short-chain fatty acids concentration was significantly lower than control group. Additionally, BBR caused gut microbiota dysbiosis by evaluating the decreased observed species number and Shannon index. BBR increased the relative abundances of families Porphyromonadaceae and Prevotellaceae as well as genera Parabacteroides, Prevotellaceae_UCG-001 and Prevotellaceae_NK3B31_group. Spearman's correlation analysis revealed family Prevotellaceae and genus Prevotellaceae_UCG-001 as the most prominent drivers of the BBR treatment-emergent diarrhea, correlating positively with fecal moisture but negatively with gastrointestinal transit time. This study therefore demonstrated that the treatment-emergent mild diarrhea of BBR was most likely due to the dysbiosis of the gut microbiota.

[Partial Nitrification Fast Start-up and Stable Performance of 15℃ SBBR].

In this study, controlled C/N effects on fast start-up and stable performance of partial nitrification process at 15℃ in a Sequenced Batch Biofilm Reactor (SBBR) were investigated. The results showed that partial nitrification successfully fast initiated when C/N was 1.5 but failed when C/N was 0/3 during 60 cycles. Fluorescence in situ hybridization and confocal laser scanning microscope (FISH-CLSM) results showed that ammonia oxidizing bacteria (AOB) was found as the dominant bacteria population when C/N was 1.5. When C/N were 0/3, there were almost no existence of AOB and nitrite oxidative bacteria (NOB). Partial nitrification could be stably achieved without carbon source. However, the addition of an appropriate amount of carbon can effectively improve the nitrification performance, and it is better for the stable operation of partial nitrification. In this experiment, partial nitrification was successfully initiated at high dissolved oxygen (DO) (about 9 mg·L-1) conditions. The average DO was maintained at about 6.5 mg·L-1 during the stable operation, which successfully decoupled partial nitrification from low DO concentration. Excessive residual ammonium concentration in the reactors effectively repressed the growth of NOB and guaranteed the stable operation of partial nitrification. At 15℃, full nitritation was more suitable for sidestream wastewater, while mainstream wastewater was more suitable for partial nitritation.

[Achieving Partial Nitritation in a Continuous-flow Aerobic Granular Sludge Reactor at Different Temperatures Through Ratio Control].

Mature aerobic granular sludge (AGS) was inoculated in a continuous-flow reactor to treat low ammonia sewage, and the feasibility of achieving partial nitritation in a continuous-flow aerobic sludge system and the demand for R value (the ratio of dissolved oxygen and ammonia nitrogen) when partial nitritation is achieved at different temperatures (30, 20, and 10℃) were investigated. The control strategy was designed to maintain a constant ratio between dissolved oxygen (DO) and ammonia nitrogen (NH4+-N). The results revealed that stable nitritation in a continuous-flow aerobic sludge reactor could be achieved via ratio control, and the value of R were 0.50 (±0.05), 0.35 (±0.03), and 0.20 (±0.02) at the temperatures 30, 20, and 10℃, respectively, from which it can be concluded that stronger oxygen-limiting conditions were required when the temperature was lower. The experiment of fluorescence in situ hybridization (FISH) revealed that ammonia oxidizing bacteria (AOB) have a certain concentration, and the relative number of nitrite oxidizing bacteria (NOB) gradually reduced through the ratio control strategy. Based on the ratio control strategy and the characteristics of wastewater quality, full nitritation of high ammonia wastewater may be allowed; however, for low ammonia wastewater, only partial nitritation is recommended.

[Characteristics of Biofilm During the Transition Process of Complete Nitrification and Partial Nitrification].

The objective of the study was to investigate the change of biofilm characteristics when implementing the procedure of partial nitrification. A ratio control strategy (DO/NH4+-N) was taken to achieve partial nitrification, and biofilm samples were obtained at 10.27%, 52.12%, and 93.54% of the nitrite accumulation rate. The amount and spatial distribution of total bacteria, ammonia oxidizing bacteria (AOB), and nitrite oxidative bacteria (NOB) were observed by fluorescence in situ hybridization (FISH) and confocal laser scanning microscope (CLSM) through a three-dimensional excitation emission matrix (EEM) to observe the secretion and composition changes of extracellular polymer substances. Ratio control successfully enriched AOB and achieved partial nitrification under conditions when NOB was not completely washed. Heterotrophic bacteria and nitrifying bacteria coexist in the biofilm. The heterotrophic bacteria were in the outer layer, but nitrifying bacteria were distributed in the biofilm surface at 6-25 µm. During the process of short-range nitrification, the AOB/NOB value gradually increased, and the stable operation period was as high as 15.56. During the operation of the reactor, EPS and microbial flora changes are closely related. When microbial activity decreased, EPS secretion decreased. During the stable operation period of partial nitrification, NOB and other bacteria that are non-resistant to high nitrite nitrous acid declined, and the fluorescence intensity of aromatic protein-like bacteria decreased. However, the three-dimensional fluorescence spectra showed that the chemical composition of EPS was not obvious during the process of partial nitrification.