Light-Driven Electron Uptake from Nonfermentative Organic Matter to Expedite Nitrogen Dissimilation by Chemolithotrophic Anammox Consortia.

Nonphotosynthetic microorganisms are typically unable to directly utilize light energy, but light might change the metabolic pathway of these bacteria indirectly by forming intermediates such as reactive oxygen species (ROS). This work investigated the role of light on nitrogen conversion by anaerobic ammonium oxidation (anammox) consortia. The results showed that high intensity light (>20000 lx) caused ca. 50% inhibition of anammox activity, and total ROS reached 167% at 60,000 lx. Surprisingly, 200 lx light was found to induce unexpected promotion of the nitrogen conversion rate, and ultraviolet light (<420 nm) was identified as the main contributor. Metagenomic and metatranscriptomic analyses revealed that the gene encoding cytochrome c peroxidase was highly expressed only under 200 lx light. 15N isotope tracing, gene abundance quantification, and external H2O2 addition experiments showed that photoinduced trace H2O2 triggered cytochrome c peroxidase expression to take up electrons from extracellular nonfermentative organics to synthesize NADH and ATP, thereby expediting nitrogen dissimulation of anammox consortia. External supplying reduced humic acid into a low-intensity light exposure system would result in a maximal 1.7-fold increase in the nitrogen conversion rate. These interesting findings may provide insight into the niche differentiation and widespread nature of anammox bacteria in natural ecotopes.

Molecular Insight into the Binding Property and Mechanism of Sulfamethoxazole to Extracellular Proteins of Anammox Sludge.

Antibiotics are widely found in nitrogen-containing wastewater, which may affect the operation stability of anaerobic ammonium oxidation (anammox)-based biological treatment systems. Extracellular polymeric substances (EPSs) of anammox sludge play a pivotal role in combining with antibiotics; however, the exact role and how the structure of the leading component of EPSs (i.e., extracellular proteins) changes under antibiotic stress remain to be elucidated. Here, the interaction between sulfamethoxazole and the extracellular proteins of anammox sludge was investigated via multiple spectra and molecular simulation. Results showed that sulfamethoxazole statically quenched the fluorescent components of EPSs, and the quenching constant of the aromatic proteins was the largest, with a value of 1.73 × 104 M-1. The overall binding was an enthalpy-driven process, with ΔH = -75.15 kJ mol-1, ΔS = -0.175 kJ mol-1 K-1, and ΔG = -21.10 kJ mol-1 at 35 °C. The O-P-O and C═O groups responded first under the disturbance of sulfamethoxazole. Excessive sulfamethoxazole (20 mg L-1) would decrease the ratio of α-helix/(ß-sheet + random coil) of extracellular proteins, resulting in a loose structure. Molecular docking and dynamic simulation revealed that extracellular proteins would provide abundant sites to bind with sulfamethoxazole, through hydrogen bond and Pi-Akyl hydrophobic interaction forces. Once sulfamethoxazole penetrates into the cell surface and combines with the transmembrane ammonium transport domain, it may inhibit the NH4+ transport. Our findings enhance the understanding on the interaction of extracellular proteins and sulfamethoxazole, which may be valuable for deciphering the response property of anammox sludge under the antibiotic stress.

Anammox Granules Acclimatized to Mainstream Conditions Can Achieve a Volumetric Nitrogen Removal Rate Comparable to Sidestream Systems.

The implementation of mainstream anammox has gained increasing attention. In this study, the feasibility of using sidestream anammox granules to start up mainstream reactors was investigated by comparing two switching strategies. A maximum nitrogen removal potential of 3.6 ± 0.2 kg N m-3 d-1 was obtained for the reactor after direct switching to mainstream conditions (70 mg TN L-1, 15 °C). Nevertheless, the reactor preacclimatized to 25 °C (Ma) exhibited a higher nitrogen removal potential of 7.0 ± 0.3 kg N m-3 d-1 at 15 °C, which is the highest volumetric nitrogen removal rate of mainstream anammox reactors to date. Candidatus Kuenenia stuttgartiensis was identified as the dominant anammox bacterium, and its relative abundance in two reactors remained stable throughout the whole operation (200 days). Moreover, with the aid of acclimatization, the activation energy was reduced and the specific growth rate became higher. These results indicated that the physiological evolution of the dominant anammox bacterium instead of interspecies selection was the main reason for the high potential during the switch to mainstream conditions. Therefore, using sidestream anammox granules as seed sludge to start up mainstream reactors was demonstrated to be feasible, and a switching strategy of acclimatization at 25 °C was recommended.

Two HSP90 genes in mandarin fish Siniperca chuatsi: identification, characterization and their specific expression profiles during embryogenesis and under stresses.

HSP90 plays important roles in multiple cellular stress responses. Here, two cytoplasmic HSP90 isoforms, ScHSP90α and ScHSP90ß, were identified from Siniperca chuatsi. Their cDNA and gDNA structures, amino acid sequence features, and sequence identities and phylogenetic analysis with other species were described. Their expression profiles during embryonic development in different tissues and under stressful conditions were analyzed using real-time quantitative PCR. During embryogenesis, transcripts of both genes were detected at low levels during the early developmental stages and were up-regulated from appearance of myomere for ScHSP90a and closure of blastopore for ScHSP90ß. ScHSP90α showed a tissue-specific variation with high expression in ovary and brain under non-stressed conditions, while ScHSP90ß was ubiquitously highly expressed in different tissues. Acute heat shock resulted in a strong up-regulation of ScHSP90α in heart, liver, and head kidney, while it only weakly induced ScHSP90ß in these tissues. ScHSP90α was also markedly induced in liver in a time-dependent manner under hypoxia, while the expression of ScHSP90ß was not affected by hypoxia. Additionally, Aeromonas hydrophila infection markedly augmented ScHSP90α in head kidney and spleen and mildly up-regulated ScHSP90ß in spleen, while suppressing ScHSP90ß in head kidney. These results suggest that ScHSP90α and ScHSP90ß are differently involved in embryogenesis and under different environmental conditions including high temperature, hypoxia, and bacterial infection. This study will benefit to further clarify the roles of fish HSP90 isoforms in embryogenesis and under stressful conditions and contribute to further study on enhancing stress tolerance and disease resistance of mandarin fish.

Quorum sensing mediated response mechanism of anammox consortia to anionic surfactant: Molecular simulation and molecular evidence.

The widespread use of surfactants raise challenges to biological wastewater treatment. Anaerobic ammonium oxidation (anammox) process has the potential to treat wastewater containing anionic surfactants, but the response of anammox consortia at the molecular level under long-term exposure is unclear. Using high-throughput sequencing and gene quantification, combined with molecular docking, the effect of sodium dodecyl sulfonate (SDS) on anammox consortia were investigated. Levels of reactive oxygen species (ROS) might be lower than the threshold of oxidative damage, while the increase of lactate dehydrogenase (LDH) represented the cell membrane damage. Decreased abundance of functional genes (hdh, hzsA and nirS) indicated the decrease of the anammox bacterial abundance. Trace amounts of N-acyl homoserine lactone (AHL, C6-HSL, C8-HSL and C12-HSL) contained in influent could induce endogenous quorum sensing (QS), which could regulate the correlation between functional bacteria to optimize the microbial community and strengthen the resistance of anammox consortia to SDS. In addition, the proliferation of disinfectant resistance genes might increase the environmental pathogenicity of sewage discharge. This work highlights the potential response mechanism of anammox consortium to surfactants and provides a universal microbial-friendly bioenhancement strategy based on QS.

Orthodontic-surgical treatment for severe skeletal class II malocclusion with vertical maxillary excess and four premolars extraction: A case report.

BACKGROUND: Patient satisfaction with facial appearance at the end of orthodontic camouflage treatment is very important, especially for skeletal malocclusion. This case report highlights the importance of the treatment plan for a patient initially treated with four-premolar-extraction camouflage, despite indications for orthognathic surgery. CASE SUMMARY: A 23-year-old male sought treatment complaining about his unsatisfactory facial appearance. His maxillary first premolars and mandibular second premolars had been extracted, and a fixed appliance had been used to retract his anterior teeth for two years without improvement. He had a convex profile, a gummy smile, lip incompetence, inadequate maxillary incisor inclination, and almost a class I molar relationship. Cephalometric analysis showed severe skeletal class II malocclusion (A point-nasion-B point = 11.5°) with a retrognathic mandible (sella-nasion-B point = 75.9°), a protruded maxilla (sella-nasion-A point = 87.4°), and vertical maxillary excess (upper incisor to palatal plane = 33.2 mm). The excessive lingual inclination of the maxillary incisors (upper incisor to nasion-A point line = -5.5°) was due to previous treatment attempts to compensate for the skeletal class II malocclusion. The patient was successfully retreated with decompensating orthodontic treatment combined with orthognathic surgery. The maxillary incisors were repositioned and proclined in the alveolar bone, the overjet was increased, and a space was created for orthognathic surgery, including maxillary impaction, anterior maxillary back-setting, and bilateral sagittal split ramus osteotomy to correct his skeletal anteroposterior discrepancy. Gingival display was reduced, and lip competence was restored. In addition, the results remained stable after 2 years. The patient was satisfied with his new profile as well as with the functional malocclusion at the end of treatment. CONCLUSION: This case report provides orthodontists a good example of how to treat an adult with severe skeletal class II malocclusion with vertical maxillary excess after an unsatisfactory orthodontic camouflage treatment. Orthodontic and orthognathic treatment can significantly correct a patient's facial appearance.

Multi-disciplinary treatment of maxillofacial skeletal deformities by orthognathic surgery combined with periodontal phenotype modification: A case report.

BACKGROUND: Maxillofacial deformities are skeletal discrepancies that cause occlusal, functional, and esthetic problems, and are managed by multi-disciplinary treatment, including careful orthodontic, surgical, and periodontal evaluations. However, thin periodontal phenotype is often overlooked although it affects the therapeutic outcome. Gingival augmentation and periodontal accelerated osteogenic orthodontics (PAOO) can effectively modify the periodontal phenotype and improve treatment outcome. We describe the multi-disciplinary approaches used to manage a case of skeletal Class III malocclusion and facial asymmetry, with thin periodontal phenotype limiting the correction of deformity. CASE SUMMARY: A patient with facial asymmetry and weakness in chewing had been treated with orthodontic camouflage, but the treatment outcome was not satisfactory. After examination, gingiva augmentation and PAOO were performed to increase the volume of both the gingiva and the alveolar bone to allow further tooth movement. After orthodontic decompensation, double-jaw surgery was performed to reposition the maxilla-mandibular complex. Finally, implant placement and chin molding were performed to restore the dentition and to improve the skeletal profile. The appearance and function were significantly improved, and the periodontal tissue remained healthy and stable. CONCLUSION: In patients with dentofacial deformities and a thin periodontal phenotype, multi-disciplinary treatment that includes PAOO could be effective, and could improve both the quality and safety of orthodontic-orthognathic therapy.

Orthodontic-surgical treatment of an Angle Class II malocclusion patient with mandibular hypoplasia and missing maxillary first molars: A case report.

BACKGROUND: Adult patients presenting with Angle Class II division 1 malocclusions that have a strong skeletal etiology can be challenging for clinicians, particularly if accompanied by retrognathia of the mandible and a dolichofacial growth pattern. CASE SUMMARY: In this case report, we describe the successful orthodontic and surgical management of a 20-year-old woman with an Angle Class II malocclusion with a severe anteroposterior skeletal discrepancy characterized by mandibular deficiency. She had incompetent lips, dental and skeletal Class II malocclusion, high mandibular plane angle, mild mandibular crowding, and two missing maxillary first molars. The treatment plan comprised: (1) Extraction of two mandibular second premolars to decompensate and retract mandibular incisors; (2) pre-surgical alignment, leveling, and space closure of the teeth in both arches, and protraction of the second maxillary molars to close the maxillary space; (3) surgical treatment including a LeFort I osteotomy for maxillary retraction and rotation, a bilateral sagittal split osteotomy for mandibular advancement and rotation, and a genioplasty for correctting the skeletal deformities; and (4) post-surgical correction of the malocclusion. CONCLUSION: The patient's facial esthetics was significantly improved and a desirable occlusion was achieved after 16 mo treatment. Follow-up records after 2 years showed stable esthetics and function.

The response of anaerobic ammonium oxidation process to bisphenol-A: Linking reactor performance to microbial community and functional gene.

As a typical endocrine disruptor, bisphenol A (BPA) has been widely detected in various water bodies. Although the influence of BPA on traditional biological treatment system has been investigated, it is not clear whether it has potential impact on anaerobic ammonium oxidation (anammox) process. The short- and long-term influences of BPA on reactor operational performance, sludge characteristics and microbial community were investigated in this study. Results revealed that 1 and 3 mg L-1 BPA exhibited a limited adverse impact on granular sludge reactor performance. However, exposure of sludge under 10 mg L-1 BPA would cause an obvious inhibition on nitrogen removal rate from 10.3 ± 0.2 to 7.6 ± 0.4 kg N m-3 d-1. BPA would affect granular sludge metabolic substance excretion and lead to effluent dissolved organic content increase. Both the microbial community and redundancy analysis showed that BPA exhibited a negative influence on Ca. Kuenenia but a positive correlation with SBR1031. Low BPA concentration appeared a limited impact on functional genes while 10 mg L-1 BPA would cause decline of hzsA and hdh abundances. The results of this work might be valuable for in-depth understanding the potential influence of endocrine disruptor on anammox sludge.

Response of the mainstream anammox process to the biodegradable carbon sources in the granule-based systems: The difference in self-stratification of the microbial community.

The inevitable introduction of biodegradable carbon sources (such as monosaccharides and volatile fatty acids) originating from pretreatment units might affect the performance of the mainstream anaerobic ammonium oxidation (anammox) process. Two model carbon sources (glucose and acetate) were selected to investigate their effects on granule-based anammox systems under mainstream conditions (70 mg total nitrogen (TN) L-1, 15 °C). At a nitrogen loading rate of 2.87 ± 0.80 kg N m-3 d-1, a satisfactory effluent quality (TN < 10 mg L-1) was achieved in the presence of glucose or acetate at a chemical oxygen demand (COD/N) ratio of 0.5. The contribution of anammox to nitrogen removal decreased with increasing COD/N ratio to 1.0 because the expression of anammox functional genes was inhibited, whereas the expression of denitrifying functional genes was promoted. However, the nitrogen removal efficiency of the two considered reactors was maintained above 80 %. Self-stratification of the microbial community along the reactor height facilitated a functional balance through the retention of anammox bacteria in granules but resulted in washout of denitrifying bacteria in flocs under a high-flow pattern. These findings highlighted the advantages of granule-based systems in the mainstream anammox process due to their inherent biomass self-segregation property and the need for the development of targeted biomass retention strategies.

Molecular spectroscopy and docking simulation revealed the binding mechanism of phenol onto anammox sludge extracellular polymeric substances.

The rapid development of chemical industry has induced to the large amount of phenolic wastewater production. When the promising anaerobic ammonium oxidation (anammox) was employed to treat the industrial wastewater, phenolic compounds would possibly inhibit the microbial performance. Extracellular polymeric substances (EPSs) play an essential role in protecting cells from being intoxicated by phenolic compound while the distinct mechanism remains elusive. In this work, the interaction of phenol with anammox sludge EPSs and transmembrane ammonium transport (Amt) domain was explored at molecular level by using spectral method and molecular docking simulation. It was found that phenol statically quenched the fluorescent components of EPSs and the protein component dominated the interaction between EPSs and phenol. The overall interaction was an entropy-driven process with hydrophobic interaction as the main driving force, and the CO vibration responded preferentially. As phenol continued to penetrate into the cell surface, there were hydrogen bond, hydrophobic interaction force and π-π base-stacking forces between the Amt domain and phenol. The interaction between phenol and amino acid residues of the Amt domain would interfere the NH4+ transport and further affect the activity of anammox sludge. This work is beneficial for in-depth understanding the role of EPSs in protecting anammox sludge from inhibiting by phenolic pollutants.

Inorganic quantum dots - anammox consortia hybrid for stable nitrogen elimination under high-intensity solar-simulated irradiation.

External stimulus such as light irradiation is able to deteriorate intracellular redox homeostasis and induce photooxidative damage to non-photogenic bacteria. Exploiting effective strategies to help bacteria resisting infaust stress is meaningful for achieving a stable operation of biological treatment system. In this work, selenium-doped carbon quantum dots (Se-CQDs) were blended into anaerobic ammonia oxidation (anammox) bacteria and an inorganic nanoparticle-microbe hybrid was successfully fabricated to evaluate its nitrogen removal performance under solar-simulated irradiation. It was found that the specific anammox activity decreased by 29.7 ± 5.2% and reactive oxygen species (ROS) content increased by 134.8 ± 4.1% under 50,000 lux light. Sludge activity could be completely recovered under the optimum dosage of 0.42 mL·(g volatile suspended solid) -1 Se-CQDs. Hydroxyl radical (·OH) and superoxide anion radical (·O2-) were identified as the leading ROS inducing lipid peroxidation and antioxidase function detriment. Also, the structure of ladderane lipids located on anammoxosome was destroyed by ROS and functional genes abundances declined accordingly. Although cell surface coated Se-CQDs could absorb ultraviolet light and partially mitigated the photoinhibition, the direct scavenging of ROS by intracellular Se-CQDs primarily contributed to the cellular redox homeostasis, antioxidase activity recovery and sludge activity improvement. The findings of this work provide in-depth understanding the metabolic response mechanism of anammox consortia to light irradiation and might be valuable for a more stable and sustainable nitrogen removal technology, i.e., algal-bacterial symbiotic system, development.

Coagulants put phosphate-accumulating organisms at a competitive disadvantage with glycogen-accumulating organisms in enhanced biological phosphorus removal system.

Enhanced biological phosphorus removal (EBPR) process is susceptible to the changed operation condition, which results in an unstable treatment performance. In this work, long-term effect of coagulants addition, aluminum salt for the reactor R1 and iron salt for the reactor R2, on EBPR systems was comprehensively evaluated. Results showed that during the initial 30 days' coagulant addition, effluent chemical oxygen demand and phosphorus can be reduced below 25 and 0.5 mg·L-1, respectively. Further supply of metal salts would stimulate microbial extracellular polymeric substance excretion and induce reactive oxygen species accumulation, which destroyed the cell membrane integrity and deteriorated the phosphorus removal performance. Moreover, coagulants would decrease the relative abundance of Candidatus Accumulibacter while increase the relative abundance of Candidatus Competibacter, leading phosphors accumulating organisms in a disadvantage position. The results of this work might be valuable for the operation of chemical assisted biological phosphorus removal bioreactor.

A review on characterizing the metabolite property of anammox sludge by spectroscopy.

As one of the most promising autotrophic biological nitrogen removal technology, anaerobic ammonia oxidation (anammox) has gained intense attention for the past decades and several full-scale facilities have been implemented worldwide. However, anammox bacteria are easily affected by disturbed external environmental factors, which commonly leads to the fluctuations in reactor performance. The response of anammox sludge to external stress results in changes in components and structural characteristics of intracellular and extracellular polymer substances. Real-time and convenient spectral analysis of anammox sludge metabolites can give early warning of performance deterioration under external stresses, which is of great significance to the stable operation of bioreactor. This review summarized the research progress on characterizing the intracellular and extracellular metabolites of anammox sludge through spectroscopic techniques. The correlation between anammox sludge activity and its key metabolites was analyzed. Also, the limitations and future prospects of applying spectral analytical techniques for anammox bioreactor monitoring were discussed and outlooked. This review may provide valuable information for both scientific study and engineering application of anammox based nitrogen removal technology.

Extracellular polymeric substances excreted by anammox sludge act as a barrier for As(III) invasion: Binding property and interaction mechanism.

The arsenic in livestock wastewater would induce adverse impact on the biological treatment technology such as anaerobic ammonium oxidation (anammox) process. Extracellular polymeric substances (EPS) play an important role in resisting such toxicity. Unfortunately, the role of EPS in protecting anammox from As(III) and the mechanisms underlying the protection still remains unclear. This work comprehensively evaluated the acute toxicity of arsenic on anammox sludge and investigated the binding property and interaction mechanism. The results revealed that the half maximal inhibitory concentration (IC50) of As(III) on anammox sludge was estimated to be 408 mg L-1, which decreased to 41.97 mg L-1 when EPS was exfoliated. Complexation and hydrophobic interactions were the leading forces in preventing arsenic invasion. Protein was the main component that complexes with As(III), and O-H, -NH, -CO were binding sites. The response sequence of organic component in EPS to As(III) was ordered as hydrocarbons-proteins-polysaccharides-aliphatic amines.

Advances and challenges of mainstream nitrogen removal from municipal wastewater with anammox-based processes.

Anaerobic ammonium oxidation (anammox) is a novel process of deammonification that exhibits superior ecological and economic potential compared to that of traditional heterotrophic processes. Although this process has been successfully implemented in treating high-strength nitrogen-contaminated wastewater, it still faces many challenges in treating mainstream municipal wastewater. This review aims to provide an overview of the status and challenges of mainstream anammox-based processes. The different configurations and crucial factors are discussed in this review. Finally, the future needs for feasible application are stated. PRACTITIONER POINTS: Factors restricting mainstream application of anammox-based processes are reviewed. Control strategies for selecting and maintaining anammox bacteria are discussed. Recent advances in nitrite production via partial nitrification or denitrification are summarized. Future needs for the feasible application of anammox-based nitrogen removal technology for mainstream municipal wastewater treatment are outlined.

Polyphenol-metal network derived nanocomposite to catalyze peroxymonosulfate decomposition for dye degradation.

Persulfate based advanced oxidation process is a promising technology for refractory contaminants removal. Cobalt is considered as the most efficient metal in catalyzing peroxymonosulfate decomposition. Although different cobalt based nanomaterials have been developed, easy aggregation and metal ion leaching during catalytic reaction would result in its deficiency. To address the above issue, in this work, carbon supported Co/CoO core-shell nanocomposite was in-situ fabricated by using polyphenol-metal coordinate as precursor. Results indicated that cobalt nanoparticle with size of 10 nm was successfully prepared and well dispersed within the carbon matrix. By using as-prepared material as catalyst, 50 mg/L orange II was completely removed under the condition of 0.2 g/L peroxymonosulfate, 0.05 g/L catalyst, pH = 4.0-10.0. Both sulfate and hydroxyl radicals were formed during peroxymonosulfate decomposition, while sulfate radical dominated the pollutant removal. Mechanism study revealed that the cobalt was the key site for catalyzing peroxymonosulfate decomposition. This work might provide valuable information in designing and fabricating metal anchored carbon composite catalyst for efficiently and cost-effectively activate peroxymonosulfate.

Resistance of anammox granular sludge to copper nanoparticles and oxytetracycline and restoration of performance.

Nanoparticles and antibiotics, the two most frequently detected emerging pollutants from different wastewater sources, are eventually discharged into wastewater treatment plants. In this study, the widely used materials CuNPs and oxytetracycline (OTC) were selected as target pollutants to investigate their joint effects on anaerobic ammonium oxidation (anammox). The results indicated that the environmental concentration slightly inhibited the performance of the reactors, while the performance rapidly deteriorated within a week under high-level combined shocks (5.0 mg L-1 CuNPs and 2.0 mg L-1 OTC). After the second shock (2.5 mg L-1 CuNPs and 2.0 mg L-1 OTC), the resistance of anammox bacteria was enhanced, with an elevated relative abundance of Candidatus Kuenenia and absolute abundance of hzsA, nirS, and hdh. Moreover, the extracellular polymeric substance (EPS) content and specific anammox activity (SAA) showed corresponding changes. Improved sludge resistance was observed with increasing CuNP and OTC doses, which accelerated the recovery of performance.

Determination of the response characteristics of anaerobic ammonium oxidation bioreactor disturbed by temperature change with the spectral fingerprint.

Anaerobic ammonium oxidation (anammox) bacteria are sensitive and susceptible to operating condition fluctuations that can lead to the instability of a bioreactor. Through multivariate spectral analysis, the dynamic changes of intracellular and extracellular metabolites of anammox sludge under the declined temperature stress were characterized. It was found that effluent fluorescence components were positively related to the bacterial activity, and the response of the protein-like substances to the temperature change was more sensitive than that of humic substances. Under the transient disturbance during temperature change from 35 to 15 °C, anammox system tended to considerably excrete extracellular polymeric substances to resist the low temperature inhibition. However, the long-term exposure of the sludge at 10 °C resulted in the considerably inhibition of sludge activity, granular disintegration and heterotrophic denitrification bacteria increase. The two-dimensional correlation analysis further revealed that the humic acid in extracellular polymeric substances was preferentially responded to the temperature change than protein. Anammox bacteria tended to increase the intracellular protein and electron transfer-related reactive substance excretion to counteract the low temperature inhibition. Herein, both the intra- and extra-cellular response characteristics of anammox sludge to temperature variation were successfully resolved via the combined spectra. This work provides a comprehensive understanding on the mechanism of anammox sludge to temperature variation and may be valuable for the development of bioreactor monitoring techniques.

A Transcriptome Analysis: Various Reasons of Adverse Pregnancy Outcomes Caused by Acute Toxoplasma gondii Infection.

BACKGROUND: Toxoplasma gondii (T. gondii) is an obligate intracellular parasite, which can affect the pregnancy outcomes in infected females by damaging the uterus, and the intrauterine environment as well as and the hypothalamus resulting in hormonal imbalance. However, the molecular mechanisms underlying the parasite-induced poor pregnancy outcomes and the key genes regulating these mechanisms remain unclear. Therefore, this study aimed to analyze the gene expression in the mouse's uterus following experimentally-induced acute infection with T. gondii RH strain. Three groups of female mice were intraperitoneally injected with tachyzoites as follow; 3 days before pregnancy (FBD6), after pregnancy (FAD6), and after implantation (FID8) as the experimental groups. Another corresponding three groups served as control, were injected with normal saline at the same time. Transcriptome analysis of the total RNA extracted from both infected and non-infected mouse uterus samples was performed using RNA sequencing (RNA-Seq). RESULTS: The three experimental groups (FBD6, FAD6, and FID8) had a total of 4,561, 2,345, and 2,997 differentially expressed genes (DEGs) compared to the controls. The significantly upregulated and downregulated DEGs were 2,571 and 1,990 genes in FBD6, 1,042 and 1,303 genes in FAD6 and 1,162 and 1,835 genes in FID8 group, respectively. The analysis of GO annotation, and KEGG pathway showed that DEGs were mainly involved in anatomical structure development, transport, cell differentiation, embryo development, hormone biosynthetic process, signal transduction, immune system process, phagosome, pathways in cancer, and cytokine-cytokine receptor interaction pathways. CONCLUSION: T. gondii infection can induce global transcriptomic changes in the uterus that may cause pregnancy hypertension, destruct the intrauterine environment, and hinder the normal development of placenta and embryo. Our results may help to understand the molecular mechanisms of the acute T. gondii infection, which could promote the development of new therapeutics or prophylactics for toxoplasmosis in pregnancy.