Microbial response and recovery strategy of the anammox process under ciprofloxacin stress from pure strain and consortia perspectives.

Ciprofloxacin (CIP) poses a high risk of resistance development in water environments. Therefore, comprehensive effects and recovery strategies of CIP in anaerobic ammonia oxidation (anammox) process were systematically elucidated from consortia and pure strains perspectives. The anammox consortia was not significantly affected by the stress of 10 mg L-1 CIP, while the higher concentration (20 mg L-1) of CIP caused a dramatic reduction in the nitrogen removal performance of anammox system. Simultaneously, the abundances of dominant functional bacteria and corresponding genes also significantly decreased. Such inhibition could not be mitigated by the recovery strategy of adding hydrazine and hydroxylamine. Reducing nitrogen load rate from 5.1 to 1.4 kg N m-3 d-1 promoted the restoration of three reactors. In addition, the robustness and recovery of anammox systems was evaluated using starvation and shock strategies. Simultaneously, antibiotic resistance genes and key metabolic pathways of anammox consortia were upregulated, such as carbohydrate and energy metabolisms. In addition, 11 pure stains were isolated from the anammox system and identified through phylogenetic analysis, 40 % of which showed multidrug resistance, especially Pseudomonas. These findings provide deep insights into the responding mechanism of anammox consortia to CIP stress and promote the application of anammox process for treating wastewater containing antibiotics.

Mitigating the detrimental effects of salt stress on anammox process: A comparison between glycine betaine and mannitol.

The use of seawater to alleviate water shortages causes an increase of salinity in municipal pipe networks, posing challenges for biological wastewater treatment. The impacts of two compatible solutes on the anammox process under salt stress (20 g L-1) were compared here at the genetic and microbial levels. The findings revealed that both 0.3 mM glycine betaine (GB) and mannitol (MA) could alleviate the salt stress on anammox process, with GB exhibiting a better effect. Specifically, the addition of GB recovered the nitrogen removal efficiency (NRE) from 40 % to >80 % within 13 days. The addition of MA caused the reduction of the absolute abundance of hdh and hzsA, implying that 0.6 mM was not the optimal concentration. Moreover, salt stress induced an increase in the absolute abundance of nitrification functional genes and a decrease in the abundance of denitrification functional genes. Notably, compared with the initial level, the abundance of Candidatus Kuenenia increased by 7.1 % and 4.3 % after adding GB and MA, respectively. According to the network analysis, two compatible solutes promoted the bacterial interactions in anammox systems, which promoted the nitrogen circulation and further the nitrogen removal performance. This work provides a feasible strategy to relieve the salt stress on anammox process and then facilitates its application for treating saline wastewater.

Removal of extracellular deoxyribonucleic acid increases the permeability and mass transfer of anammox granular sludge with different sizes.

As a key component of extracellular polymeric substances (EPS), extracellular deoxyribonucleic acid (eDNA) acts as a bridge in maintaining the structural stability of granular sludge. However, its ability of carrying antibiotic resistance genes (ARGs) promotes the gene horizontal transfer, raising a high risk for human health. In this study, a series of batch tests were performed to elucidate the response of anammox granular sludge (AnGS) with different sizes (S-AnGS with diameters lower than 0.9 mm and L-AnGS with diameters of 0.9-2 mm) to the removal of eDNA and corresponding mechanism. The results showed that the highest bioactivity of S-AnGS and L-AnGS was achieved by adding DNase I, and the absolute abundance of hzsA in the systems also increased. The dominant microorganism in each sludge was Candidatus Kuenenia, which maintained a higher relative abundance of 24% in S-AnGS. Settling experiments demonstrated that the permeability of AnGS was positively correlated with the addition of DNase I. The permeability index of granular sludge, Г, rose by 58.54% in S-AnGS and 11.79% in L-AnGS. The absence of eDNA is conducive to the increase in the permeability and porosity of AnGS. Similarity in the functional genes and microbial communities of intracellular and extracellular DNA implied the occurrence of gene transmembrane transfer. The findings enrich our knowledge of eDNA in anammox granules and provide a guidance for the specific control of gene transfer through reducing eDNA.

Long non-coding RNA ELFN1-AS1-mediated ZBTB16 inhibition augments the progression of gastric cancer by activating the PI3K/AKT axis.

Long non-coding RNA ELFN1 antisense RNA 1 (ELFN1-AS1) has been reported as a cancer driver in many human malignancies. This study was conducted to investigate the function of ELFN1-AS1 in gastric cancer (GC) and its mechanism of action. Bioinformatics analysis revealed increased expression of ELFN1-AS1 in GC, and abundant expression of ELFN1-AS1 was observed in the acquired GC cell lines. Knockdown of ELFN1-AS1 in GC cells weakened cell proliferation, invasion, migration, and resistance to apoptosis. ELFN1-AS1 was mainly localized in the nuclei of GC cells. ELFN1-AS1 recruited DNA methyltransferases to the promoter region of ZBTB16 and induced transcriptional repression of ZBTB16 through methylation modification. Furthermore, downregulation of ZBTB16 activated the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway and restored the proliferation and invasiveness of GC cells. In vivo, downregulation of ELFN1-AS1 reduced the growth rate of xenograft tumors in mice. In summary, this study demonstrates that ELFN1-AS1 recruits DNA methyltransferases to the promoter region of ZBTB16 to induce its transcriptional repression, which further augments the development of GC by activating the PI3K/AKT signaling pathway.

Intracellular and extracellular protective mechanisms of the anammox consortia against exogenous sulfadimidine.

Antibiotics and antibiotic resistance genes (ARGs) have been recognized as emerging high-risk pollutants for human and animal health. This study systematically investigated the comprehensive effects of a typical antibiotic (sulfadimidine, SDM) in livestock and poultry breeding wastewater on the anammox process, with the aim of elucidating the intracellular and extracellular protective mechanisms of the anammox consortia to the antibiotic stress. Results revealed that the high-concentration SDM significantly reduced the specific anammox activity (SAA) by 37.8%. Changes in the abundance of Candidatus Kuenenia showed a similar trend with that of SAA, while other nitrogen-related microorganisms (e.g., Nitrosomonas and Nitrospira) contributed to the nitrogen removal especially during the inhibitory period. Resistance of the anammox consortia to SDM mainly depended on the protection of ARGs and EPS. Network analysis revealed the host range of eARGs was relatively larger than that of iARGs, and intI1 was closely associated with representative denitrifiers. In addition, metaproteomic analysis and molecular docking results indicated that abundant proteins in EPS could detain SDM in the extracellular matrix through forming complex via hydrogen bond. These findings provide a guidance for the stable operation of anammox process and ARGs transfer controlling.

How anammox process resists the multi-antibiotic stress: Resistance gene accumulation and microbial community evolution.

The effects of multiple antibiotics on the anaerobic ammonia oxidation (anammox) process were investigated. The resistance of the anammox system to high-concentration antibiotics was also demonstrated through gradual acclimation experiments. Inhibition of the anammox process (R1) occurred when the concentrations of erythromycin (ERY), sulfamethoxazole (SMX) and tetracycline (TC) were 0.1, 5.0 and 0.1 mg L-1, respectively. The nitrogen removal efficiency (NRE) of R1 was reduced from 97.2% to 60.7% within 12 days and then recovered to 88.9 ± 9.5% when the nitrogen loading declined from 4.52 ± 0.69 to 2.11 ± 0.58 kg N m-3 d-1. Even when the concentrations of ERY, SMX and TC were as high as 1.0, 15.0 and 1.0 mg L-1, respectively, R1 maintained stable operation. The increases in the abundance of antibiotic resistance genes (ARGs) and in extracellular polymeric substances (EPS) content showed that the anammox process alleviated stress from multiple antibiotics mainly by producing ARGs and secreting EPS. The molecular docking simulation results illustrated the potential binding sites between ammonium transporter and different antibiotics. The upregulation of functional gene expression and the stable abundance of Candidatus Kuenenia in R1 compared with that in the control suggested that the R1 reactor generally maintained more stable long-term operation. This work provides a new understanding of the application of the anammox process to treat wastewater containing multiple antibiotics.

Inhibition of wastewater pollutants on the anammox process: A review.

The anaerobic ammonium oxidation (anammox) process has been recognized as an efficient nitrogen removal technology. However, anammox bacteria are susceptible to surrounding environments and different pollutants, which limits the extensive application of the anammox process worldwide. Numerous researchers investigate the effects of various pollutants on the anammox process or bacteria, and related findings have also been reviewed with the focused on their inhibitory effects on process performance and microbial community. This review systemically summarized the recent advances in the inhibition, mechanism and recovery process of traditional and emerging pollutants on the anammox process over a decade, such as organics, metals, antibiotics, nanoparticles, etc. Generally, low-concentration pollutants exhibited a promotion on the anammox activity, while high-concentration pollutants showed inhibitory effects. The inhibitory threshold concentration of different pollutants varied. The combined effects of multipollutant also attracts more attentions, including synergistic, antagonistic and independent effects. Additionally, remaining problems and research needs are further proposed. This review provides a foundation for future research on the inhibition in anammox process, and promotes the proper operation of anammox processes treating different types of wastewaters.

Resistance genes and extracellular proteins relieve antibiotic stress on the anammox process.

The anaerobic ammonium oxidation (anammox) process is regarded as a promising approach to treat antibiotic-containing wastewater. Therefore, it is urgent to elucidate the effects of various antibiotics on the anammox process. Moreover, the mechanism of extracellular polymeric substance (EPS) as protective barriers to relieve antibiotic stress remain unclear. Therefore, the single and combined effects of erythromycin (ETC) and sulfamethoxazole (SMZ), and interactions between EPS and antibiotics were investigated in this study. Based on a 228-day continuous flow experiment, high concentrations of ETC and SMZ had significant inhibitory effects on the nitrogen removal performance of the anammox process, with the abundances of corresponding antibiotic resistance genes (ARGs) increasing. In addition, the combined inhibitory effect of the two antibiotics on the anammox process was more significant and longer-lasting than that of the single. However, the anammox process was able to quickly recover from deterioration. The tolerance of anammox granules to the stress of low-concentration antibiotics was probably attributed to the increase in ARGs and secretion of EPS. Molecular docking simulation results showed that proteins in EPS could directly bind with SMZ and ETC at the sites of GLU-307, HYS-191, ASP-318 and THR-32, respectively. These findings improved our understanding of various antibiotic effects on the anammox process and the interaction mechanism between antibiotics and proteins in EPS.

Comparison of the dynamic responses of different anammox granules to copper nanoparticle stress: Antibiotic exposure history made a difference.

Two types of anaerobic ammonium oxidation (anammox) seed sludge were selected to evaluate their responses to copper nanoparticles (CuNPs) exposure. Antibiotic-exposed anammox granules (R1) were more likely to be inhibited by 5.0 mg L-1 CuNPs than the normal anammox granules (C1). The nitrogen removal efficiency (NRE) of C1 decreased by 9.00% after two weeks of exposure to CuNPs, whereas that of R1 decreased by 20.32%. Simultaneously, the abundance of Candidatus. Kuenenia decreased by 27.65% and 36.02% in C1 and R1 under CuNPs stress conditions, respectively. Generally, R1 was more susceptible to CuNPs than C1. The correlation analysis indicated that the horizontal transfer of antibiotic resistance genes and copA triggered by intI1 facilitated the generation of multiresistance in the anammox process. Moreover, the potential multiresistance mechanism of anammox bacteria was hypothesized based on previous results. The results will generate new ideas for the treatment of complex wastewater using the anammox process.

Response of anammox granules to the simultaneous exposure to macrolide and aminoglycoside antibiotics: Linking performance to mechanism.

Antibiotic pollution is becoming increasingly severe due to its extensive use. The potential application of the anaerobic ammonium oxidation (anammox) process in the treatment of wastewater containing antibiotics has attracted much attention. As common antibiotics, spiramycin (SPM) and streptomycin (STM) are widely used to treat human and animal diseases. However, their combined effects on the anammox process remain unknown. Therefore, this study systematically evaluated the response of the anammox process to both antibiotics. The half maximal inhibitory concentrations of SPM and STM were determined. The continuous-flow anammox system could adapt to SPM and STM at low concentrations, while antibiotics at high concentrations exhibited inhibitory effects. When the concentrations reached 5 mg L-1 SPM and 50 mg L-1 STM, the nitrogen removal efficiency dramatically decreased and then rapidly recovered within 8 days. Correspondingly, the abundances of dominant bacteria and genes also changed with antibiotic concentrations. In general, the anammox process showed a stable performance and a high resistance to SPM and STM, suggesting that acclimatization by elevating the concentrations was beneficial for the anammox process to obtain resistance to different antibiotics with high concentrations. This study provides guidance for the stable operation of anammox-based biological treatment of antibiotics containing wastewater.

Role of miR-155-5p expression and its involvement in apoptosis-related factors in thyroid follicular carcinoma.

WHAT IS KNOWN AND OBJECTIVE: Thyroid follicular carcinoma is a malignant tumor from thyroid follicular epithelium, which is prone to involve capsular and vascular invasion. The present study was conducted in order to detect the expression of microRNA-155-5p (miR-155-5p) in thyroid follicular carcinoma with an attempt to analyze its involvement in apoptosis-related factors. METHODS: Forty-five patients with thyroid follicular carcinoma made up the observation group and 45 patients with thyroid follicular adenoma were included into the control group. Tissues of thyroid follicular carcinoma and thyroid follicular adenoma were obtained from the patients, and analysed for expression of miR-155-5p by real-time fluorescence quantitative PCR (qPCR). The expression of cysteine-containing aspartic acid protein hydrolase-3 (Caspase-3) in thyroid follicular carcinoma was detected with the use of Western Blot analyses. Immunohistochemical method was used to detect the expression of B-cell lymphoma protein-2 (Bcl-2) in thyroid follicular carcinoma. RESULTS: There was significant difference in the expression of miR-155-5p between the two groups (Observation vs Control: 1.46 ± 0.42 vs 0.98 ± 0.33 P < .05). The expression of miR-155-5p was significantly different in the maximum diameter of tumor, vascular invasion and neural invasion (maximum diameter of tumor <4 cm vs ≥4 cm: 1.36 ± 0.40 vs 1.68 ± 0.32, vascular invasion N vs Y: 1.35 ± 0.42 vs 1.69 ± 0.39, Neural invasion N vs Y: 1.35 ± 0.38 vs 1.70 ± 0.31 P < .05). However, there was no significant difference in the expression of miR-155-5p in terms of different gender, age and group with or without lymph node metastasis (P > .05). Based on survival analysis, patients with high expression of miR-155-5p experienced short survival time (median survival time was 45 months, P < .05). There was a negative correlation between miR-155-5p and Caspase-3 (r = -.50, P < .05). In addition, positive correlation was observed between miR-155-5p and Bcl-2 (r = .55, P < .05). WHAT IS NEW AND CONCLUSION: There was increased expression of miR-155-5p in thyroid follicular carcinoma. The abnormal expression of miR-155-5p may be an independent prognostic factor for thyroid follicular carcinoma associated with cell apoptosis.

Deciphering the microbial community and functional genes response of anammox sludge to sulfide stress.

Sulfide has attracted increasing attention due to its odor nuisance, toxicity and corrosion. Although variations in the nitrogen removal performance of anammox under sulfide stress have been reported previously, understanding the microorganisms at the molecular level is of greater significance. This study first deciphered the microbial community and functional gene response of anammox sludge to sulfide stress. Results showed that 20 mg L-1 sulfide could reduce specific anammox activity by 61.7%. The protein-like substances within extracellular polymeric substances were quenched at the end of the experiment. Moreover, the relative abundance of Candidatus Kuenenia significantly decreased from 28.7% to 6.4% while Thiobacillus increased from 0 to 7.2% due to sulfide stress. Furthermore, the abundances of functional genes (hzsA, hdh, nirK and nirS) significantly decreased when the sulfide concentration reached 20 mg L-1. These findings provide a further theoretical basis for the anammox process for nitrogen removal from wastewater containing sulfide.

Identification of CD200+ colorectal cancer stem cells and their gene expression profile.

CD200 is a cell surface glycoprotein that has been implicated in a variety of human cancer cells. It has been proposed as a cancer stem cell (CSC) marker in colon cancer and is closely related to tumor immunosuppression. However, there is little functional data supporting its role as a true CSC marker, and the mechanism by which CD200 contributes to colorectal cancer has not been elucidated. In the present study, CD200+ and CD200- COLO 205 colorectal cancer cells were sorted out by flow cytometry, and colonosphere formation and Transwell migration assays were performed. Affymetrix Human U133 Plus2.0 arrays were used to screen the gene expression profiles of CD200+ and CD200- colorectal cancer cells. The results suggest that there are differentially expressed genes between the two subpopulations, including several important genes that function in cell proliferation, metastasis, apoptosis and the immune response. Pathway analysis revealed that the Wnt, MAPK and calcium signaling pathways were differentially expressed between CD200+ and CD200- cells. Moreover, several key genes upregulated in CD200+ cells were also highly overexpressed in CD44+CD133+ colorectal stem cells compared to the CD44-CD133- fraction of the same cell line. In the present study, we showed for the first time a correlation between CD200 expression and the Wnt signaling pathway in colon cancer cells.