[Health Risk Assessment of Heavy Metals in Soils of a City in Guangdong Province Based on Source Oriented and Monte Carlo Models].

Taking a city in Guangdong Province as the research area, the concentration and spatial distribution characteristics of heavy metals in the surface soil were studied to clarify the situation of soil heavy metal pollution and priority control factors, providing basic data for the prevention and control of soil heavy metal pollution in the city. The content characteristics of heavy metals in 221 soil samples in the city were analyzed, and the potential health risk assessment and source analysis were carried out through the Monte Carlo model, the potential health risk assessment (HRA) model, and the PMF receptor model. It was found that heavy metals ω(As), ω(Hg), ω(Cd), ω(Pb), ω(Cr), ω(Cu), ω(Ni), and ω(Zn) in the soil of the city were 18.16, 0.43, 1.46, 68.57, 98.34, 64.19, 26.53, and 257.32 mg·kg-1, respectively, with a moderate to high degree of variation. Except for Ni concentration, the soil concentrations of other heavy metal elements exceeded the background values of soil in Guangdong Province to a certain extent, and the concentrations of Cd and Zn exceeded the national secondary standards, resulting in severe heavy metal pollution; the main sources of heavy metals were industrial sources, and natural parent materials, lead battery manufacturing, transportation, artificial cultivation, and pesticide and fertilizer inputs also had an undeniable impact on the accumulation of heavy metals in the soil. Heavy metals in the soil had a certain degree of tolerable carcinogenic health risk for both children and adults, whereas non-carcinogenic risks could be ignored. The potential health risk of children was greater than that of adults, and the main exposure route was through oral intake. The input sources of pesticides and fertilizers and As should be the main controlling factors for the health risks of heavy metals in the city's soil, followed by mixed sources and Cr. There were differences in the spatial distribution characteristics and relative pollution levels of heavy metals, and it is necessary to deepen zoning monitoring and control, strengthen soil pollution prevention and control, and reduce human input of heavy metals in soil.

[Prokaryotic Expression and Bioinformatic Analysis of Rv3432c From Mycobacterium tuberculosis]. / ç»“æ ¸åˆ†æžæ†èŒRv3432cè›‹ç™½çš„åŽŸæ ¸è¡¨è¾¾ä¸Žç”Ÿç‰©ä¿¡æ¯å­¦åˆ†æž.

Objective: To express the protein enconded by the Rv3432c gene of Mycobacterium tuberculosis (M.tb) in vitro by prokaryotic expression, to analyze the structure of the Rv3432c protein by using bioinformatics software, and to explore for new drug targets against M.tb. Methods: The Rv3432c gene was amplified by PCR using the genomic DNA of the inactivated M.tb strain H37Rv as the template and a recombinant plasmid was constructed with the expression vector pET-28a. The expression products were analyzed by SDS-PAGE and purified using affinity chromatography. The biological properties of Rv3432c were analyzed with Protparam, the Pfam online tool, SOMPA, Protscale, TMHMM Signalp 6.0, NetPhos3.1, SUMOsp 2.0, and SWISS-MODEL. Results: pET-28a-Rv3432c recombinant plasmid sequencing results were fully consistent with those of the target gene. SDS-PAGE analysis showed that the fusion protein existed in the form of a soluble protein with a relative molecular mass of about 55×103, which matched the expected size. ProtParam analysis showed that the Rv3432c protein was hydrophilic (showing a GRAVY value of －0.079). Rv3432c was a protein with no transmembrane structural domains or signal peptide. The secondary structure of Rv3432c mainly consisted of random coils (39.78%) and α-helix (39.57%) and was relatively loosely structured. Conclusion: We successfully constructed a prokaryotic expression plasmid of the Rv3432c protein and analyzed its structure using bioinformatics, laying the foundation for further research on the role of Rv3432c in the pathogenesis and progression of tuberculosis as well as the identification of new drug targets against M.tb.

[A new nor-neolignan compound identified from Itea yunnanensis].

Various separation methods in combination with spectral data analysis, X-ray single crystal diffraction analysis, and litera-ture data comparison were employed to clarify the chemical constituents of Itea yunnanensis. Seven compounds were obtained from I. yunnanensis, which were identified as(S)-3-[1-(4-hydroxyphenyl)propane-2-yl]-4-methoxybenzoate methyl ester(1), iteafuranal B(2), syringaresinol(3), dihydrokaempferol(4), trimethoxybenzene(5), eicosane(6), and nonacosane(7), respectively. Among them, compound 1 was a new nor-neolignan compound named iteanorneoligan A, and the rest of the compounds were identified from I. yunnanensis for the first time. The anti-hepatocellular carcinoma effect of the compound was evaluated based on Sk-hep-1 cells model via MTT assay, and compound 2 showed a significant inhibitory effect on the proliferation of Sk-hep-1 cells with an IC_(50) of 9.4 µmol·L~(-1). The antioxidant capacity was determined via DPPH, ABTS~(·+), and O■ radical scavenging ability, and compound 1 exhibited a significant ABTS~(·+) radical scavenging effect with an IC_(50) of 0.178 mg·mL~(-1).

[Pollution Characteristics and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Soils of Guangzhou].

In order to comprehensively study the pollution characteristics of polycyclic aromatic hydrocarbons （PAHs） in soils of Guangzhou， 222 topsoil samples were collected and analyzed. The ecological risk of soil PAHs pollution was evaluated using the effect interval low/median method （ERL/ERM） and the （BaP） toxicity equivalent method， and the health risk of soil PAHs pollution was evaluated using the lifelong cancer risk increment model. The source of PAHs was analyzed using the characteristic compound ratio method and PMF model. The results indicated that： the content of surface soil （∑16PAHs） in Guangzhou was 38-11 115 µg·kg-1， with an average of 526 µg·kg-1， and 16 types of polycyclic aromatic hydrocarbon monomers showed strong variation. There was a certain degree of ecological risk of PAHs in Guangzhou， and there was already a significant ecological risk of PAHs pollution in individual sampling points， which were generally in a state of mild pollution. Based on the results of the health risk assessment， the contribution rates of total cancer risk in both adults and children were presented as follows： skin contact > ingestion of soil > respiratory intake. The health risk of children was greater than that of adults， and the overall health risk was within an acceptable range. Source analysis showed that the main sources of soil PAHs in Guangzhou were coal （37.1%）； diesel （32%）； coking （17.3%）； and mixed sources of traffic emissions， biomass combustion， and petrochemical product volatilization （13.6%）. The overall source of soil PAHs belonged to mixed sources. The research results have enriched our understanding of the pollution status of PAHs in the surface soil of Guangzhou and are helpful in promoting soil pollution prevention and control actions.

HLA-DQB1*05 subtypes and not DRB1*10:01 mediates risk in anti-IgLON5 disease.

Anti-IgLON5 disease is a rare and likely underdiagnosed subtype of autoimmune encephalitis. The disease displays a heterogeneous phenotype that includes sleep, movement, and bulbar-associated dysfunction. Presence of IgLON5-antibodies in CSF/serum, together with a strong association with HLA-DRB1*10:01∼DQB1*05:01, support an autoimmune basis. In this study, a multicentric HLA study of 87 anti-IgLON5 patients revealed a stronger association with HLA-DQ than HLA-DR. Specifically, we identified a predisposing rank-wise association with HLA-DQA1*01:05∼DQB1*05:01, HLA-DQA1*01:01∼DQB1*05:01 and HLA-DQA1*01:04∼DQB1*05:03 in 85% of patients. HLA sequences and binding cores for these three DQ heterodimers were similar, unlike those of linked DRB1 alleles, supporting a causal link to HLA-DQ. This association was further reflected in an increasingly later age of onset across each genotype group, with a delay of up to 11 years, while HLA-DQ-dosage dependent effects were also suggested by reduced risk in the presence of non-predisposing DQ1 alleles. The functional relevance of the observed HLA-DQ molecules was studied with competition binding assays. These proof-of-concept experiments revealed preferential binding of IgLON5 in a post-translationally modified, but not native, state to all three risk-associated HLA-DQ receptors. Further, a deamidated peptide from the Ig2-domain of IgLON5 activated T cells in two patients, compared to one control carrying HLA-DQA1*01:05∼DQB1*05:01. Taken together, these data support a HLA-DQ-mediated T cell response to IgLON5 as a potentially key step in the initiation of autoimmunity in this disease.

Diabetes mellitus and Alzheimer's disease: Vacuolar adenosine triphosphatase as a potential link.

Globally, the incidence of diabetes mellitus (DM) and Alzheimer's disease (AD) is increasing year by year, causing a huge economic and social burden, and their pathogenesis and aetiology have been proven to have a certain correlation. In recent years, more and more studies have shown that vacuolar adenosine triphosphatases (v-ATPases) in eukaryotes, which are biomolecules regulating lysosomal acidification and glycolipid metabolism, play a key role in DM and AD. This article describes the role of v-ATPase in DM and AD, including its role in glycolysis, insulin secretion and insulin resistance (IR), as well as its relationship with lysosomal acidification, autophagy and ß-amyloid (Aß). In DM, v-ATPase is involved in the regulation of glucose metabolism and IR. v-ATPase is closely related to glycolysis. On the one hand, v-ATPase affects the rate of glycolysis by affecting the secretion of insulin and changing the activities of key glycolytic enzymes hexokinase (HK) and phosphofructokinase 1 (PFK-1). On the other hand, glucose is the main regulator of this enzyme, and the assembly and activity of v-ATPase depend on glucose, and glucose depletion will lead to its decomposition and inactivation. In addition, v-ATPase can also regulate free fatty acids, thereby improving IR. In AD, v-ATPase can not only improve the abnormal brain energy metabolism by affecting lysosomal acidification and autophagy but also change the deposition of Aß by affecting the production and degradation of Aß. Therefore, v-ATPase may be the bridge between DM and AD.

Enterovirus 71 leads to abnormal mitochondrial dynamics in human neuroblastoma SK-N-SH cells.

EV71, a significant pathogen causing hand-foot-mouth disease, is associated with severe neurological complications such as brain stem encephalitis, aseptic meningitis, and acute flaccid paralysis. While the role of mitochondrial dynamics in regulating the replication of numerous viruses is recognized, its specific involvement in EV71 remains unclear. This study aimed to elucidate the role of mitochondrial dynamics in human neuroblastoma SK-N-SH cells during EV71 infection. Utilizing laser confocal microscopy and transmission electron microscopy, we observed that EV71 infection induced mitochondrial elongation and damage to cristae structures, concurrently accelerating mitochondrial movement. Furthermore, we identified the reduction in the expression of dynamin-related protein 1 (Drp1) and optic atrophy protein 1 (Opa1) and the increased expression of Mitofusion 2 (Mfn2) upon EV71 infection. Notably, EV71 directly stimulated the generation of mitochondrial reactive oxygen species (ROS), leading to a decline in mitochondrial membrane potential and ATP levels. Remarkably, the application of melatonin, a potent mitochondrial protector, inhibited EV71 replication by restoring Drp1 expression. These findings collectively indicate that EV71 induces alterations in mitochondrial morphology and dynamics within SK-N-SH cells, potentially impairing mitochondrial function and contributing to nervous system dysfunction. The restoration of proper mitochondrial dynamics may hold promise as a prospective approach to counteract EV71 infection.

A Europium Metal-Organic Framework and Its Polymer Composite Membrane as Switch-Off Fluorescence Sensors for Antibiotic Detection in Lake Water.

The detection of antibiotic residues is of great significance in monitoring their overuse in healthcare, livestock and poultry farming, and agricultural production. Herein, EuCl3 and 4,4'-dicarboxyl-diphenoxyethene (H2DPOE) ionothermally reacted in 1-methyl-3-butylimidazolium chloride to give a europium metal-organic framework (Eu-DPOE). Eu-DPOE shows different fluorescence quenching rates for sensing eight antibiotics under different excitation wavelengths. Eu-DPOE displays a fast response, high selectivity, and sensitivity in antibiotic detection by fluorescence quenching. Eu-DPOE can sensitively detect TCs (tetracyclines), NOR (norfloxacin), NFT (furazolidone), ODZ (ornidazole), SDZ (sulfadiazine), and CHL (chloramphenicol) with limits of detection below 0.5 µmol/L. It provides a convenient and rapid tool for sensing antibiotics in aqueous solution. The detection mechanism is a competition absorption between DPOE2- and antibiotics with the supports from powder X-ray diffraction (PXRD), UV-vis spectra, and fluorescence lifetime. With a composite membrane of poly(vinylidene fluoride) (PVDF) matrix loading Eu-DPOE (Eu-DPOE@PVDF), Eu-DPOE@PVDF exhibits a visual fluorescence response to NOR under a 254 nm UV lamp and NFT and CTC under 365 nm. Eu-DPOE@PVDF is applied in the quantitative detection of CTC, NOR, and NFT in lake water with recovery rates ranging from 88.37 to 113.8%. Totally, fluorescence-quenched Eu-DPOE@PVDF exhibits a fast response, high selectivity, and sensitivity in sensing CTC, NOR, and NFT.

[Clinical observation of virtual reality technology combined with isokinetic strength training for patients after anterior cruciate ligament reconstruction].

OBJECTIVE: To explore application value and effectiveness of virtual reality technology combined with isokinetic muscle strength training in the rehabilitation of patients after anterior cruciate ligament (ACL) reconstruction surgery. METHODS: Forty patients who underwent ACL reconstruction surgery from December 2021 to January 2023 were selected and divided into control group and observation group according to treatment methods, 20 patients in each group. Control group was received routine rehabilitation training combined with isokinetic muscle strength training, including 15 males and 5 females, aged from 17 to 44 years old, with an average of (29.10±8.60) years old. Observation group was performed virtual reality technology combined with isokinetic muscle strength training, including 16 males and 4 females, aged from 17 to 45 years old with an average of (30.95±9.11) years old. Lysholm knee joint score, knee extension peak torque, and knee flexion peak torque between two groups at 12 (before training) and 16 weeks (after training) after surgery were compared. RESULTS: All patients were followed up for 1 to 6 months with an average of (3.30±1.42) months. There were no statistically significant difference in Lysholm knee joint score, peak knee extension peak torque, and peak knee flexion peak torque between two groups (P>0.05) before training. After training, Lysholm knee joint score, knee extension peak torque, and knee flexion peak torque of both groups were improved compared to before training (P<0.05);there were significant difference in Lysholm knee joint score, knee extension peak torque, and knee flexion peak torque between two groups(P<0.05). CONCLUSION: The application of virtual reality technology combined with isokinetic muscle strength training could promote recovery of knee joint function and enhance muscle strength in patients after ACL reconstruction surgery in further.

Two new 2-arylbenzo[b]furans from Itea indochinensis and their anti-hepatocellular carcinoma and anti-oxidant effects.

Two new 2-arylbenzo[b]furans (1-2) and ten known compounds (3-12) were identified from the 95% EtOH extract of the branches and leaves of Itea indochinensis for the first time. Their structures were determined mainly based on extensive analyses of UV, IR, 1D/2D NMR and HRMS spectra. The results of MTT assays demonstrated the anti-tumor potential of compound 1 with good selectivity, which displayed moderate inhibitory effects on proliferation of SK-hep-1 cells with IC50 value of 22.3 µM, while weak inhibitory effect on proliferation of HepG2 cells with an inhibition rate of 25% at 20 µM, and no obviously inhibitory effect on proliferation of A549 cells at 20 µM. In addition, compound 1 exhibited its significant scavenging capacity on ABTS·+ free radical with an IC50 value of 0.11 mg/mL, while weak scavenging effects on DPPH and O2·- radicals with scavenging ratios of 32.93% and 21.49% at 1 mg/mL, respectively.

FNIII14 Peptide-Enriched Membrane Nanocarrier to Disrupt Stromal Barriers through Reversing CAFs for Augmenting Drug Penetration in Tumors.

Given the key roles of cancer associated fibroblasts (CAFs) in shaping tumor stroma, this study shows a CAF-associated ITGB1-inactivating peptide-enriched membrane nanodelivery system (designated as PMNPs-D) to simultaneously target CAFs and tumor cells for boosted chemotherapy through promoted drug perfusion. In the structure of PMNPs-D, the PLGA-based inner core is loaded with the chemotherapeutic drug doxorubicin, and the outer surface is cloaked by hybrid biomembranes with the insertion of integrin ß1 (ITGB1) inhibiting peptide (i.e., FNIII14). After prolonged blood circulation and actively targeting in tumor sites, PMNPs-D can respond to CAF-overexpressed fibroblast activation protein-α (FAP-α) to trigger the release of FNIII14, which will bind to ITGB1 and inhibit CAFs' biological function in producing the stromal matrix, thereby loosening the condensed stromal structure and enhancing the permeability of nanotherapeutics in tumors. As a result, this tailor-designed nanosystem shows substantial tumor inhibition and metastasis retardation in aggressive adenoid cystic carcinoma (ACC) tumor-harboring mice.

Dual Pd-Acid Sites Confined in a Hierarchical Core-Shell Structure for Hydrogenation of Nitrobenzene.

A core-shell structured Pd@TS-1@meso-SiO2 catalyst with confined Pd nanometals has been fabricated by one-pot synthesis, impregnation method and sol-gel method. With the promotion of acid sites and protection of mesoporous silica shell, Pd@TS-1@meso-SiO2 shows higher activity than commercial comparison and higher stability than sample without mesoporous silica shell in the hydrogenation of nitrobenzene. The schematic illustration of the synergy effect is also proposed.

Impacts of Nile Tilapia (Oreochromis niloticus) exposed to microplastics in bioflocs system.

Microplastics (MPs) are abundant in aquaculture water, including in bioflocs aquaculture systems. Compared with other aquaculture systems, biofloc technology systems have the richest microbes and are beneficial to cultivated organisms. Therefore, this study provides a comprehensive assessment of the potential effects of MPs on aquaculture organisms in bioflocs systems. Here, Nile Tilapia (Oreochromis niloticus) were exposed to MPs (polystyrene; 32-40 µm diameter) with 0, 80 items/L (30 µg/L), and 800 items/L (300 µg/L) for 28 days in a bioflocs aquaculture system. The results showed that the MPs generally had no apparent effect on water quality, tilapia growth, or digestive enzyme activity. However, MPs accumulated the most in the liver (5.65 ± 0.74 µg/mg) and significantly increased the hepato-somatic index of tilapia and reduced the crude protein and lipid of tilapia muscle (p < 0.05). The levels of the antioxidant enzymes catalase and glutathione S-transferase increased significantly in response to MPs (p < 0.05). In contrast, MPs did not affect the content of glutathione, glutathione peroxidase, oxidized glutathione, and malondialdehyde, or the enzyme activity of Na+/K+-ATPase. Moreover, using an improved integrated biomarker response index, growth performance was found to be less responsive to MPs than to oxidative stress and digestive activity. Exposure to MPs did not significantly influence the microbial communities of the bioflocs and tilapia guts (p < 0.05). These results suggest that MPs barely affected tilapia in the bioflocs system. This study contributes to the evaluation of the ecological risk of MPs in aquaculture systems and a better understanding of the integrated response of cultivated vertebrates to MPs in biofloc technology systems.

Immunostimulant Hydrogel-Guided Tumor Microenvironment Reprogramming to Efficiently Potentiate Macrophage-Mediated Cellular Phagocytosis for Systemic Cancer Immunotherapy.

Macrophage-mediated cellular phagocytosis (MMCP) plays a critical role in conducting antitumor immunotherapy but is usually impaired by the intrinsic phagocytosis evading ability of tumor cells and the immunosuppressive tumor microenvironment (TME). Herein, a MMCP-boosting hydrogel (TCCaGM) was elaborately engineered by encapsulating granulocyte-macrophage colony-stimulating factor (GM-CSF) and a therapeutic nanoplatform (TCCaN) that preloaded with the tunicamycin (Tuni) and catalase (CAT) with the assistance of CaCO3 nanoparticles (NPs). Strikingly, the hypoxic/acidic TME was efficiently alleviated by the engineered hydrogel, "eat me" signal calreticulin (CRT) was upregulated, while the "don't eat me" signal CD47 was downregulated on tumor cells, and the infiltrated DCs were recruited and activated, all of which contributed to boosting the macrophage-mediated phagocytosis and initiating tumor-specific CD8+ T cells responses. Meanwhile, the remodeled TME was beneficial to accelerate the polarization of tumor-associated macrophages (TAMs) to the antitumoral M1-like phenotype, further heightening tumoricidal immunity. With the combination of PD-1 antibody (αPD-1), the designed hydrogel significantly heightened systemic antitumor immune responses and long-term immunological effects to control the development of primary and distant tumors as well as suppress tumor metastasis and recurrence, which established an optimal strategy for high-performance antitumor immunotherapy.

Multiancestry analysis of the HLA locus in Alzheimer's and Parkinson's diseases uncovers a shared adaptive immune response mediated by HLA-DRB1*04 subtypes.

Across multiancestry groups, we analyzed Human Leukocyte Antigen (HLA) associations in over 176,000 individuals with Parkinson's disease (PD) and Alzheimer's disease (AD) versus controls. We demonstrate that the two diseases share the same protective association at the HLA locus. HLA-specific fine-mapping showed that hierarchical protective effects of HLA-DRB1*04 subtypes best accounted for the association, strongest with HLA-DRB1*04:04 and HLA-DRB1*04:07, and intermediary with HLA-DRB1*04:01 and HLA-DRB1*04:03. The same signal was associated with decreased neurofibrillary tangles in postmortem brains and was associated with reduced tau levels in cerebrospinal fluid and to a lower extent with increased Aß42. Protective HLA-DRB1*04 subtypes strongly bound the aggregation-prone tau PHF6 sequence, however only when acetylated at a lysine (K311), a common posttranslational modification central to tau aggregation. An HLA-DRB1*04-mediated adaptive immune response decreases PD and AD risks, potentially by acting against tau, offering the possibility of therapeutic avenues.

Narcolepsy risk loci outline role of T cell autoimmunity and infectious triggers in narcolepsy.

Narcolepsy type 1 (NT1) is caused by a loss of hypocretin/orexin transmission. Risk factors include pandemic 2009 H1N1 influenza A infection and immunization with Pandemrix®. Here, we dissect disease mechanisms and interactions with environmental triggers in a multi-ethnic sample of 6,073 cases and 84,856 controls. We fine-mapped GWAS signals within HLA (DQ0602, DQB1*03:01 and DPB1*04:02) and discovered seven novel associations (CD207, NAB1, IKZF4-ERBB3, CTSC, DENND1B, SIRPG, PRF1). Significant signals at TRA and DQB1*06:02 loci were found in 245 vaccination-related cases, who also shared polygenic risk. T cell receptor associations in NT1 modulated TRAJ*24, TRAJ*28 and TRBV*4-2 chain-usage. Partitioned heritability and immune cell enrichment analyses found genetic signals to be driven by dendritic and helper T cells. Lastly comorbidity analysis using data from FinnGen, suggests shared effects between NT1 and other autoimmune diseases. NT1 genetic variants shape autoimmunity and response to environmental triggers, including influenza A infection and immunization with Pandemrix®.

Study on 2-arylbenzo[b]furans from Itea omeiensis and their fragmentation patterns with Q-Orbitrap mass spectrometry.

One new 2-arylbenzo[b]furan named iteafuranal F (1) as well as two known analogues (2-3) were isolated from the 95% EtOH extract of aerial parts of Itea omeiensis. Their chemical structures were constructed based on extensive analyses of UV, IR, 1D/2D NMR and HRMS spectra. Antioxidant assays revealed significant superoxide anion radical scavenging capacity of 1 with IC50 value of 0.66 mg/mL, which was comparable to the efficiency of positive control of luteolin. In addition, the preliminary MS fragmentation patterns in negative ion mode were established to distinguish 2-arylbenzo[b]furans with C-10 in different oxidation states: the characteristic loss of CO molecule [M-H-28]- was observed for 3-formyl-2-arylbenzo[b]furans, and the loss of CH2O fragment [M-H-30]- for 3-hydroxymethyl-2-arylbenzo[b]furans, and the loss of CO2 fragment [M-H-44]- for 2-arylbenzo[b]furan-3-carboxylic acids.

Microplastics inhibit biofloc formation and alter microbial community composition and nitrogen transformation function in aquaculture.

Biofloc technology, extensively used in intensive aquaculture systems, can prompt the formation of microbial aggregates. Microplastics (MPs) are detected abundantly in aquaculture waters. This study explored the effects of MPs on biofloc formation, microbial community composition and nitrogen transformation function in simulated biofloc aquaculture production systems. The formation process and settling performance of bioflocs were examined. High-throughput sequencing of 16S and 18S rRNA genes was used to investigate the microbial community compositions of bioflocs. Nitrogen dynamics were monitored and further explained from functional genes and microorganisms related to nitrogen transformation by metagenome sequencing. We found that the aggregates consisting of bioflocs and MPs were formed and the systems with MPs had relatively weak settling performance. No significant differences in bacterial diversity (p > 0.05) but significant differences in eukaryotic diversity (p < 0.05) were found between systems without and with MPs. Significant separations in the microbial communities of prokaryotes (p = 0.01) and eukaryotes (p = 0.01) between systems without and with MPs were observed. The peak concentration of nitrite nitrogen (NO2--N) in systems with MPs was lower than that in systems without MPs (pControl/MPs Low = 0.02 and pControl/MPs High = 0.03), probably due to the low abundance of hao and affiliated Alphaproteobacteria_bacterium_HGW-Alphaproteobacteria-1 and Alphaproteobacteria_bacterium, but the high abundance of nxrA and affiliated Alphaproteobacteria_bacterium_SYSU_XM001 and Hydrogenophaga_pseudoflava that related to nitrification. The low concentration of NO2--N in systems with MPs suggested that the presence of MPs might inhibit ammonia oxidation but promote nitrite oxidation by altering the microbial community structure and function. These results indicated that aggregates consisting of bioflocs and MPs could be formed in aquaculture water, and thus, inhibiting their settlement and altering nitrogen transformation function by affecting the microbial community composition.