Practical gram-scale synthesis of bicyclol metabolites M2 and M3.

Bicyclol, an innovative hepatoprotective drug, was approved by the Chinese National Medical Products Administration (NMPA) in 2001 to treat Hepatitis B and drug-induced liver injury. Two active metabolites of bicyclol have been identified as M2 and M3. To evaluate the impact on drug safety and efficacy of possible drug-drug interactions (DDIs) associated with these metabolites, a sufficient quantity of these metabolites is required. Herein, we report a concise novel route for the synthesis of M2 and M3 using the Suzuki-Miyaura coupling as the key step. Furthermore, we complete the gram-scale syntheses of M2 and M3.

A new PEDV strain CH/HLJJS/2022 can challenge current detection methods and vaccines.

BACKGROUND: Porcine epidemic diarrhea virus (PEDV) variant strains cause great economic losses to the global swine industry. However, vaccines do not provide sufficient protection against currently circulating strains due to viral mutations. This study traced the molecular characteristics of the most recent isolates in China and aimed to provide a basis for the prevention and treatment of PEDV. METHODS: We obtained samples from a Chinese diarrheal swine farm in 2022. Reverse transcription polymerase chain reaction and immunofluorescence were used to determine the etiology, and the full-length PEDV genome was sequenced. Nucleotide similarity was calculated using MEGA to construct a phylogenetic tree and DNASTAR. Mutant amino acids were aligned using DNAMAN and modeled by SWISS-MODEL, Phyre2 and FirstGlance in JMOL for protein tertiary structure simulation. Additionally, TMHMM was used for protein function prediction. RESULTS: A PEDV virulent strain CH/HLJJS/2022 was successfully isolated in China. A genome-wide based phylogenetic analysis suggests that it belongs to the GII subtype, and 96.1-98.9% homology existed in the whole genomes of other strains. For the first time, simultaneous mutations of four amino acids were found in the highly conserved membrane (M) and nucleocapsid (N) proteins, as well as eight amino acid mutations that differed from the vast majority of strains in the spike (S) protein. Three of the mutations alter the S-protein spatial structure. In addition, typing markers exist during strain evolution, but isolates are using the fusion of specific amino acids from multiple variant strains to add additional features, as also demonstrated by protein alignments and 3D models of numerous subtype strains. CONCLUSION: The newly isolated prevalent strain CH/HLJJS/2022 belonged to the GII subtype, and thirteen mutations different from other strains were found, including mutations in the highly conserved m and N proteins, and in the S1° and COE neutralizing epitopes of the S protein. PEDV is breaking through original cognitions and moving on a more complex path. Surveillance for PEDV now and in the future and improvements derived from mutant strain vaccines are highly warranted.

Correlation analysis of coronary artery tortuosity and calcification score.

BACKGROUND: Coronary artery tortuosity (CAT) is regarded as a variation of vascular anatomy, and its relationship with coronary artery calcification (CAC) score is still not well clarified. Studying the correlation between coronary artery calcification scores and CAT to determine specific prevention and intervention populations seems to have more meaningful. METHODS: The study is a cross-sectional retrospective study, including 1280 patients. CAT is defined as the presence of at least three consecutive curvatures of more than 45°measured during systole or diastole of a major epicardial coronary artery. Multivariable regression analysis was used to adjust the clinical parameters directly affecting CAT. RESULTS: Of these individuals, 445 (35%) were evaluated having CAT, of which females are higher than males (59.1% vs. 40.9%). Moderate CAC score (101-400) (odds ratio (OR) 1.49, 95% confidence interval [95%CI] 1.05-2.10, P = 0.025) revealed significantly associated with CAT on univariable analysis. However, multivariable analysis after adjusting for confounding factors only indicated that CAT was positively correlated with female (OR 1.68, 95%CI 1.30-2.17, P < 0.001), hypertension (OR 1.35, 95% CI 1.04-1.75, P = 0.024), and age (OR 1.02, 95% CI 1.01-1.03, P = 0.001), while was negatively associated with body mass index (BMI) 24-27.9(OR 0.76, 95% CI 0.58-1.00, P = 0.044), and BMI > 28 (OR 0.46, 95% CI 0.31-0.68, P < 0.001). Further analysis stratified by gender showed that compared with non-CAT, CAT was significantly linked with moderate CAC score (OR 1.79, 95% CI 1.00-3.20, P = 0.048), hypertension (OR 1.54, 95% CI 1.07-2.22, P = 0.021), and high-density lipoprotein (HDL) (OR 1.86, 95% CI 1.07-3.24, P = 0.028), while was negatively related to BMI > 28 (OR 0.51, 95% CI 0.31-0.84, P = 0.008) in female patients. CONCLUSIONS: CAT is more likely to be found in females, connected with hypertension, age, and BMI. No significant correlation is found between the presence of tortuosity and calcium score or diameter stenosis on multivariable analysis. Whereas the CAT is associated with moderate CAC score in correlation analysis when women are selected as the main group.

MHC class I diversity predicts non-random mating in Chinese alligators (Alligator sinensis).

The major histocompatibility complex (MHC) has several important roles in kin recognition, pathogen resistance and mate selection. Research in fish, birds and mammals has suggested that individuals optimise MHC diversity, and therefore offspring fitness, when choosing mates. In reptiles, however, it is unclear whether female mate choice is based on genome-wide genetic characteristics such as microsatellite DNA loci, particular functional-trait loci (e.g., MHC) or both, and MHC's effects on mate choice remain relatively understudied. Herein, we used 13 microsatellite loci and two MHC class I loci to investigate female mate choice of Chinese alligators (Alligator sinensis) in the semi-natural condition. We also determined correlations between the MHC genotype of breeding males and male reproductive success. We found that MHC-heterozygous males harbour a greater reproductive success, which probably is the reason that these males are more preferred by the females than MHC-homozygous males. Furthermore, the MHC class I amino-acid distance and functional distance of true mating pairs were higher compared with those of randomly sampled pairs. Analysis of microsatellites revealed that, despite mate choice, females did not completely avoid inbreeding. These findings are the first evidence of MHC-associated mate choice in Chinese alligators, suggesting that females may adopt different mating strategies after assessing the MHC characteristics of potential mates.

[Pain assessment of biological conduit small gap tubulization in rat sciatic nerve multilation model].

OBJECTIVE: To explore the pain sensation recovery discipline of 2 mm small gap biological conduit tubulization and epineurial neurorrhaphy in rat sciatic nerve multilation model. METHODS: Based on the rat sciatic nerve multilation model, 2 mm small gap biological conduit tubulization and epineurial neurorrhaphy were applied and the 50% paw withdrawal threshold was observed after 2, 4, 5, 6, 8 and 12 weeks. The data were analyzed by two-way ANOVA and chi-square criterion. RESULTS: Obvious hyperalgesia was observed in week 2 in both experimental group and control group, and 50% paw withdrawal threshold was improved significantly even to 15 g. The 50% paw withdrawal threshold began to decline week 4 and the 50% paw withdrawal threshold of small gap tubulization group was obviously lower than that of control group, which may imply that the pain sensation recovery of small gap tubulization group was earlier than that of control group. The 50% paw withdrawal threshold of small gap tubulization group began to increase to the plateau period [week 5: (12.70 ± 5.64) g; week 6: (12.20 ± 3.26) g; week 8: (12.31 ± 4.19) g; week 12: (13.95 ± 2.58) g]. The 50% paw withdrawal threshold of control group declined gradually [week 5: (10.47 ± 7.02) g; week 6: (9.42 ± 6.86) g; week 8: (8.50 ± 7.15) g; week 12: (8.06 ± 5.93) g]. The difference was statistical significant between small gap tubulization group and control group in 12th week. CONCLUSION: Compared with the traditional epineurial neurorrhaphy for peripheral nerve multilation, 2 mm small gap biological conduit tubulization can improve the 50% paw withdrawal threshold during peripheral nerve regeneration process and reduce the pain incidence.

Association of lipoprotein(a) with left ventricular hypertrophy in patients with new-onset acute myocardial infarction: A large cross-sectional study.

BACKGROUND: The association of lipoprotein(a) [Lp(a)] with echocardiography-estimated left ventricular hypertrophy (LVH) in high-risk population remains uncertain, so we assessed the association between Lp(a) with echocardiography-derived LVH in patients with new-onset acute myocardial infarction (AMI). METHODS: In this large, single-center, cross-sectional observational study, we enrolled 2,096 patients with new-onset AMI. Lp(a) was used as the independent variable and LVH was used as the dependent variable. Logistic regression, subgroup and sensitivity analysis were performed to test the association of Lp(a) with LVH. RESULTS: The concentration of Lp(a) was higher in LVH group compared with the non-LVH group (P < 0.001). Multivariate logistic regression analysis showed that higher Lp(a) was strongly associated with higher risk of LVH, independently of traditional cardiovascular risk factors (Fully adjusted model, Q4 vs Q1, OR: 1.941, 95% CI: 1.343-2.803, P < 0.001). Subgroup analysis showed that the association of Lp(a) with LVH persisted in the subgroups of age (<60 and ≥60 years), sex (male and female), smoking (yes and no), diabetes (yes), hypertension (yes), hyperlipidemia (yes), and chronic kidney diseases (yes and no). Further sensitivity analysis indicated that Lp(a) remained significantly associated with LVH after further adjusting for high-sensitivity C-reactive protein or excluding patients with estimated glomerular filtration rate < 30 ml/min/1.73 m2 or dividing Lp(a) into multiple dichotomous variables. CONCLUSION: Lp(a) was closely associated with LVH in patients with new-onset AMI.

Efficacy and safety of daratumumab in the treatment of relapsed/refractory multiple myeloma: A meta-analysis of randomized controlled trials.

BACKGROUND: Daratumumab as a monoclonal antibody has shown promising results in the treatment of relapsed/refractory multiple myeloma (RRMM). However, the efficacy and safety of daratumumab-based regimens compared to control regimens have not been fully established. METHODS: The search was conducted using electronic databases (PubMed, Web of Science, Embase, and Cochrane Central Register of Controlled Trials databases) up to December 2022. We conducted a meta-analysis of randomized controlled trials that evaluated the efficacy and safety of daratumumab in the treatment of RRMM. Data were extracted from eligible studies and were presented as hazard ratio or risk ratio (RR) with 95% confidence interval (CI). RESULTS: A total of 5 randomized controlled trials comprising 2003 patients were included in this meta-analysis. The results showed that daratumumab-based regimens significantly improved progression-free survival compared to control regimens (hazard ratio = 0.44, 95% CI 0.32-0.60, P < .00001). Additionally, daratumumab-based regimens significantly improved overall response rate compared to control regimens (RR = 1.25, 95% CI 1.16-1.36, P < .00001). the rate of minimal residual disease was also significantly higher in the daratumumab-based regimens (RR = 6.10, 95% CI 4.09-9.11, P < .00001). However, there was an increased risk of pneumonia, upper respiratory tract infections, and diarrhea in the daratumumab-based regimens. CONCLUSION: Our results suggest that daratumumab-based regimens are effective in the treatment of RRMM, improving progression-free survival, minimal residual disease, and overall response rate. However, there is an increased risk of pneumonia, upper respiratory tract infections, and diarrhea. Further studies are needed to determine the long-term safety and efficacy of daratumumab in the treatment of multiple myeloma.

Association of lipoprotein(a) with all-cause and cause-specific mortality: A prospective cohort study.

BACKGROUND: A growing number of studies have demonstrated a causal association between lipoprotein(a) [Lp(a)] and atherosclerotic cardiovascular diseases (ASCVDs), but its association with all-cause and cause-specific mortality remains unclear. Therefore, this study aimed to explore the association of Lp(a) with all-cause and cause-specific mortality. METHODS: This prospective cohort study included 8,525 participants from the third National Health and Nutrition Examination Survey. Lp(a) was considered an exposure variable, all-cause and cause-specific mortality were used as outcome variables, and all participants were followed from the interview date until death or December 31, 2015. COX proportional hazards regression models, stratified analysis, sensitivity analysis, restricted cubic spline plots and Kaplan-Meier survival curves were used to analyze the association of Lp(a) with all-cause and cause-specific mortality. RESULTS: After adjusting for traditional cardiovascular risk factors, Lp(a) remained strongly associated with all-cause and CVDs-related mortality (P for trend = 0.007 and < 0.001). Subgroup analyses showed that higher Lp(a) remained associated with higher risk of all-cause mortality in those > 60 years of age, with a BMI < 30 kg/m2, and without diabetes, whereas the association between Lp(a) and CVDs-related mortality remained stable in participants ≤ 60 years of age, male, with a BMI < 30 kg/m2, with hypertension, without diabetes, or without CVDs (P < 0.05). In sensitivity analyses, we found that the association of Lp(a) with all-cause and CVDs-related mortality remained robust after excluding individuals who died within one year of follow-up (P for trend = 0.041 and 0.002). CONCLUSIONS: Lp(a) was associated with the risk of all-cause and CVDs-related mortality.

Programmed cell death in atherosclerosis and vascular calcification.

The concept of cell death has been expanded beyond apoptosis and necrosis to additional forms, including necroptosis, pyroptosis, autophagy, and ferroptosis. These cell death modalities play a critical role in all aspects of life, which are noteworthy for their diverse roles in diseases. Atherosclerosis (AS) and vascular calcification (VC) are major causes for the high morbidity and mortality of cardiovascular disease. Despite considerable advances in understanding the signaling pathways associated with AS and VC, the exact molecular basis remains obscure. In the article, we review the molecular mechanisms that mediate cell death and its implications for AS and VC. A better understanding of the mechanisms underlying cell death in AS and VC may drive the development of promising therapeutic strategies.

PRL-3 and MMP9 Expression and Epithelial-Mesenchymal Transition Markers in Circulating Tumor Cells From Patients With Colorectal Cancer: Potential Value in Clinical Practice.

Objective: To evaluate the clinical correlation of epithelial-mesenchymal transition (EMT) with PRL-3 and MMP9 expression in the circulating tumor cells (CTCs) of patients with colorectal cancer (CRC). Materials and Methods: Between January 2016 and December 2018, the EMT phenotype-based subsets of CTCs and the expression levels of PRL-3 and MMP9 in CTCs were identified, and their clinical values in 172 patients were evaluated. The CTCs were isolated, classified, and counted using the CanPatrol™ CTC filtration system. The CTC subsets (epithelial cells, mesenchymal cells and biphenotypic cells), as well as PRL-3 and MMP9 expression, were detected by RNA in situ hybridization. Results: CTCs were detected in 93.0% (160/172) of the included patients with CRC. Positive PRL-3 and MMP9 expression in CTC and M-CTC was found in 75.0% (102/136) and 80.8% (97/120) of the patients, respectively. The proportion of patients with positive PRL-3 and MMP9 expression in M-CTC was significantly associated with distant metastasis (p<0.05). The patients with ≥6 CTCs tended to show poorer progression-free survival (PFS) and overall survival (OS) rates (p=0.016, 0.02, respectively), and the patients with ≥3 M-CTC also showed poor PFS (p=0.0013). Additionally, the patients with positive PRL-3 and MMP9 expression in CTCs had significantly poorer PFS (p=0.0024) and OS (p=0.095) than the patients with negative PRL-3 and MMP9 expression. Multivariate Cox analysis uncovered that positive PRL-3 and MMP9 expression in CTCs may be an independent prognostic factor for worse PFS. Conclusion: EMT phenotypes and CTC numbers can be used as prognostic indicators for metastasis and survival in patients with CRC, and the combination of PRL-3 and MMP9 expression in CTCs is a promising clinical marker for patients with CRC.

Intra-Articular Biomechanical Changes of the Meniscus and Ligaments During Stance Phase of Gait Circle after Different Anterior Cruciate Ligament Reconstruction Surgical Procedures: A Finite Element Analysis.

OBJECTIVE: The debate on the superiority of single- or double-bundle for anterior cruciate ligament reconstruction has not ceased. The comparative studies on intra-articular biomechanics after different surgical reconstructions are rare. This study is to evaluate the biomechanical stress distribution intra-knee after single- and double-bundle anterior cruciate ligament reconstruction by three-dimensional finite element analysis, and to observe the change of stress concentration under the condition of vertical gradient loads. METHODS: In this study, magnetic resonance imaging data were extracted from patients and healthy controls for biomechanical analysis. Patients included in the three models were matched in age and sex. The strength and distribution of induced stresses were analyzed in two frequently used procedures, anatomical single-bundle anterior cruciate ligament reconstruction and anatomical double-bundle anterior cruciate ligament reconstruction, using femoral-graft-tibial system under different loads, to mimic a post-operation mechanical motion. The three-dimensional finite-element models for normal ligament and two surgical methods were applied. A vertical force simulating daily walking was performed on the models to assess the interfacial stresses and displacements of intra-articular tissues and ligaments. The evaluation results mainly included the stress of each part of ligament and meniscus. The stress values of different parts of three models were extracted and compared. RESULTS: The stress of ligament/graft at femoral side of three finite-element models was significantly higher than at tibial side, while the highest level was observed in single-bundle reconstruction finite-element model. With the increase of force, the maximum stress in the medial (7.1-7.1 MPa) and lateral (4.9-7.4 MPa) meniscus of single-bundle reconstruction finite-element model shifted from the anterior horn to the central area (p = 0.0161, 0.0479, respectively). The stress was shown to be at a lower level at femoral side and posterior cruciate ligament of intra-knee in two reconstruction finite-element models than that in normal finite-element models, while presented higher level at the tibial side than normal knee (p = 0.3528). The displacement of the femoral side and intra-knee areas in reconstruction finite-element models was greater than that in normal finite-element model (p = 0.0855). CONCLUSION: Compared with the single-bundle technique, the graft of double-bundle anterior cruciate ligament reconstruction has better stress dissipation effect and can prevent postoperative meniscus tear more effectively.

[Change of early serum TNF-alpha and IL-6 levels in acute cerebral infarction and its significances].

OBJECTIVE: To investigate the change of early serum TNF-alpha and IL-6 levels in acute cerebral infarction and its significances. METHODS: Serum TNF-alpha and IL-6 levels in 30 health subjects and 35 patients with acute cerebral infarction (ACI) within 6 hours of onset were measured by enzyme linked immunosorbent assay (ELISA); neurological deficits scores (NDS) in all cases were determined, and Spearman test was used for correlation. RESULTS: The serum levels of TNF-alpha and IL-6 in ACI group were markedly higher than those in health subjects and there was a positive correlation of TNF-alpha and IL-6 levels with 6 h NDS (rs=0.89 and 0.93, P<0.001) and with NDS progression (rs=0.90 and 0.91, P<0.001). Early serum TNF-alpha and IL-6 levels in progressive cerebral infarction (PCI) group were evidently higher than those in stable cerebral infarction (SCI)[(49.56+/-12.12) pg/L compared with (24.30+/-7.4) ng/L and (39.76+/-7.88) ng/L compared with (20.78+/-6.28) ng/L, respectively, P<0.01)]. CONCLUSION: The early serum levels of TNF-alpha and IL-6 in ACI markedly increase and are closely correlated with disease severity; which may be of value in PCI risk evaluation.

Metagenomics Reveals Seasonal Functional Adaptation of the Gut Microbiome to Host Feeding and Fasting in the Chinese Alligator.

As a natural hibernator, the Chinese alligator (Alligator sinensis) is an ideal and intriguing model to investigate changes in microbial community structure and function caused by hibernation. In this study, we used 16S rRNA profiling and metagenomic analysis to compare the composition, diversity, and functional capacity in the gut microbiome of hibernating vs. active Chinese alligators. Our results show that gut microbial communities undergo seasonal restructuring in response to seasonal cycles of feeding and fasting in the Chinese alligator, but this animal harbors a core gut microbial community primarily dominated by Proteobacteria, Fusobacteria, Bacteroidetes, and Firmicutes across the gut regions. During hibernation, there is an increase in the abundance of bacterial taxa (e.g., the genus Bacteroides) that can degrade host mucin glycans, which allows adaptation to winter fasting. This is accompanied by the enrichment of mucin oligosaccharide-degrading enzyme and carbohydrate-active enzyme families. In contrast, during the active phase (feeding), active Chinese alligators exhibit a carnivore gut microbiome dominated by Fusobacteria, and there is an increase in the relative abundance of bacteria (e.g., Cetobacterium somerae) with known proteolytic and amino acids-fermentating functions that improve host protein-rich food digestion efficiency. In addition, seasonal variations in the expression of ß-defensins play a protective role in intestinal immunity. These findings provide insights into the functional adaptations of host-gut microbe symbioses to seasonal dietary shifts to maintain gut homeostasis and health, especially in extreme physiological states.

Elevated levels of interleukin-1ß, interleukin-6, tumor necrosis factor-α and vascular endothelial growth factor in patients with knee articular cartilage injury.

BACKGROUND: Inflammatory cytokines play a vital role in the occurrence of osteoarticular injury and inflammation. Whether inflammation-associated factors interleukin-1ß (IL-1ß), IL-6, tumor necrosis factor-α (TNF-α) and vascular endothelial growth factor (VEGF) are involved in the pathogenesis of keen articular cartilage injury remains poorly understood. AIM: To measure the levels of inflammatory factors [IL-1ß, IL-6, TNF-α and VEGF] in patients with knee articular cartilage injury. METHODS: Fifty-five patients with knee articular cartilage injury were selected as patient groups, who were divided into three grades [mild (n = 20), moderate (n = 19) and severe (n = 16)] according to disease severity and X-ray examinations. Meanwhile, 30 healthy individuals who underwent physical examination were selected as the control group. The levels of IL-1ß, IL-6, TNF-α and VEGF were measured by ELISA and immunohistochemical staining. RESULTS: Compared with the control group, patient groups displayed significantly higher levels of IL-1ß, IL-6, TNF-α and VEGF, and the extent of increase was directly proportional to the severity of injury (P < 0.05). In addition, the number of cells with positive staining of IL-1ß, IL-6, TNF-α and VEGF in the synovial membrane were significantly increased, along with increased disease severity (P < 0.05). After treatment, the scores of visual analogue scale and the Western Ontario and McMaster University of Orthopaedic Index in patient groups were 2.26 ± 1.13 and 15.56 ± 7.12 points, respectively, which were significantly lower than those before treatment (6.98 ± 1.32 and 49.48 ± 8.96). Correlation analysis suggested that IL-1ß and TNF-α were positively correlated with VEGF. CONCLUSION: IL-1ß, IL-6, TNF-α and VEGF levels are increased in patients with knee articular cartilage injury, and are associated with the disease severity, indicating they might play an important role in the occurrence and development of knee articular cartilage injury. Furthermore, therapeutically targeting them might be a novel approach for the treatment of keen articular cartilage injury.

Study on physicochemical properties of ionic liquids based on alanine [Cnmim][Ala] (N=2,3,4,5,6).

According to Fukumoto's method, a new series of ionic liquids (ILs) based on alanine, [Cnmim][Ala] ( n=2,3,4,5,6), which comprise 1-alkyl-3-methylimidazolium cation ([Cnmim](+)) and alanine anions ([Ala] (-)), were prepared and characterized. In terms of standard addition method, the density and surface tension of amino acid ILs [Cnmim][Ala] (1-alkyl-3-methylimidazolium alpha-aminopropionic acid salt) were measured in the temperature range 293.15-343.15+/-0.05 K. The volume and surface properties of the ILs [Cnmim][Ala] were discussed. A new method of determining parachor of ionic compound was proposed and was applied to estimate the physicochemical properties of amino acid ionic liquids (AAILs): molecular volume, surface tension, molar enthalpy of vaporization, and thermal expansion coefficient. In comparison with Deetlefs's method of using neutral parachor contribution, the method proposed in this work makes smaller error in estimating properties of AAILs.

Enhanced nitrogen and phosphorus removal from domestic wastewater via algae-assisted sequencing batch biofilm reactor.

This study proposed a potential strategy for enhancement of nutrients removal from domestic wastewater by adding algae to sequencing batch biofilm reactor (SBBR) to form a novel algal-bacterial symbiosis (ABS) system. Results indicated that the algae-assisted SBBR increased the total nitrogen and phosphorus removal efficiencies from 38.5% to 65.8%, and from 31.9% to 89.3%, respectively. The carriers fixed at the top of the reactor were favorable for both formation of ABS system and algae enrichment. The chlorophyll-a increased to 3.59 mg/g at stable stage, which was 4.07 times higher than that in suspension. Moreover, the bio-carrier replacement and sludge discharge were independent, indicating that the sludge and algae retention time could be separated. The mechanisms analysis suggested that the enhanced nitrogen and phosphorus mainly attributed to the enrichment of both algae biomass and total biomass in biofilm. This study highlights the significance of developing ABS system for wastewater treatment.

Effect of aeration rate on performance and stability of algal-bacterial symbiosis system to treat domestic wastewater in sequencing batch reactors.

This study investigated aeration rate (0, 0.2, 0.4 and 1.0L/min) effects on algal-bacterial symbiosis (ABS) and conventional activated sludge (CAS) systems while treating domestic wastewater in sequencing batch reactors. Experiment results showed that ABS system performed better on NH4+-N, total nitrogen and total phosphorus removal than CAS system, especially under lower aeration rate condition (0.2Lair/min), with removal efficiencies improvements of 18.90%, 12.45% and 46.66%, respectively. The mechanism study demonstrated that a favorable aeration rate reduction (half of traditional value in CAS system) could enhance algae growth but weaken hydraulic shear force, which contributed to the interactions between algae and sludge flocs and further stability of ABS system. In addition, algae growth protected both ammonia and nitrite oxidizing bacteria from optical damage. It is expected that the present study would provide some new insights into ABS system and be helpful for development of low-energy demand wastewater treatment process.