Deciphering the formation of granules by n-DAMO and Anammox microorganisms.

Nitrate/nitrite-dependent anaerobic methane oxidation (n-DAMO) process is a promising wastewater treatment technology, but the slow microbial growth rate greatly hinders its practical application. Although high-level nitrogen removal and excellent biomass accumulation have been achieved in n-DAMO granule process, the formation mechanism of n-DAMO granules remains unresolved. To elucidate the role of functional microbes in granulation, this study attempted to cultivate granules dominated by n-DAMO microorganisms and granules coupling n-DAMO with anaerobic ammonium oxidation (Anammox). After long-term operation, dense granules were developed in the two systems where both n-DAMO archaea and n-DAMO bacteria were enriched, whereas granulation did not occur in the other system dominated by n-DAMO bacteria. Extracellular polymeric substances (EPS) measurement indicated the critical role of EPS production in the granulation of n-DAMO process. Metagenomic and metatranscriptomic analyses revealed that n-DAMO archaea and Anammox bacteria were active in EPS biosynthesis, while n-DAMO bacteria were inactive. Consequently, more EPS were produced in the systems containing n-DAMO archaea and Anammox bacteria, leading to the successful development of n-DAMO granules. Furthermore, EPS biosynthesis in n-DAMO systems is potentially regulated by acyl-homoserine lactones and c-di-GMP. These findings not only provide new insights into the mechanism of granule formation in n-DAMO systems, but also hint at potential strategies for management of the granule-based n-DAMO process.

Anaerobic ammonium oxidation coupled with sulfate reduction links nitrogen with sulfur cycle.

Sulfate-dependent ammonium oxidation (Sulfammox) is a critical process linking nitrogen and sulfur cycles. However, the metabolic pathway of microbes driven Sulfammox is still in suspense. The study demonstrated that ammonium was not consumed with sulfate as the sole electron acceptor during long-term enrichment, probably due to inhibition from sulfide accumulation, while ammonium was removed at âˆ¼ 10 mg N/L/d with sulfate and nitrate as electron acceptors. Ammonium and sulfate were converted into nitrogen gas, sulfide, and elemental sulfur. Sulfammox was mainly performed by Candidatus Brocadia sapporoensis and Candidatus Brocadia fulgida, both of which encoded ammonium oxidation pathway and dissimilatory sulfate reduction pathway. Not sulfide-driven autotrophic denitrifiers but Candidatus Kuenenia stuttgartiensis converted nitrate to nitrite with sulfide. The results of this study reveal the specialized metabolism of Sulfammox bacteria (Candidatus Brocadia sapporoensis and Candidatus Brocadia fulgida) and provide insight into microbial relationships during the nitrogen and sulfur cycles.

Deep insights into the biofilm formation mechanism and nitrogen-transformation network in a nitrate-dependent anaerobic methane oxidation biofilm.

Nitrate/nitrite-dependent anaerobic methane oxidation (n-DAMO) process offers a promising solution for simultaneously achieving methane emissions reduction and efficient nitrogen removal in wastewater treatment. Although nitrogen removal at a practical rate has been achieved by n-DAMO biofilm process, the mechanisms of biofilm formation and nitrogen transformation remain to be elucidated. In this study, n-DAMO biofilms were successfully developed in the membrane aerated moving bed biofilm reactor (MAMBBR) and removed nitrate at a rate of 159 mg NO3--N L-1 d-1. The obvious increase in the content of extracellular polymeric substances (EPS) indicated that EPS production was important for biofilm development. n-DAMO microorganisms dominated the microbial community, and n-DAMO bacteria were the most abundant microorganisms. However, the expression of biosynthesis genes for proteins and polysaccharides encoded by n-DAMO archaea was significantly more active compared to other microorganisms, suggesting the central role of n-DAMO archaea in EPS production and biofilm formation. In addition to nitrate reduction, n-DAMO archaea were revealed to actively express dissimilatory nitrate reduction to ammonium and nitrogen fixation. The produced ammonium was putatively converted to dinitrogen gas through the joint function of n-DAMO archaea and n-DAMO bacteria. This study revealed the biofilm formation mechanism and nitrogen-transformation network in n-DAMO biofilm systems, shedding new light on promoting the application of n-DAMO process.

Evidence for Nitrous Oxide Emissions by Nitrite-Dependent Anaerobic Methane Oxidizing Bacteria.

Nitrite-dependent anaerobic methane oxidizing (n-DAMO) bacteria generally convert nitrite to dinitrogen and bypass the nitrous oxide (N2O) formation step. However, N2O is often detected in n-DAMO bacteria dominated cultures and it remains an open question as to the microbial origin of N2O in these enrichments. Using a stable nitrite consuming microbial community enriched for n-DAMO bacteria, we demonstrated that N2O production was coupled to methane oxidation and the higher initial nitrite concentrations led to increased quantities of N2O being formed. Moreover, continuous exposure of the enrichment culture to about 5 mg of N L-1 nitrite resulted in constant N2O being produced (12.5% of nitrite was reduced to N2O). Metatranscriptomic analyses revealed that nitrite reductase (nirS) and nitric oxide reductase (norZ) transcripts from n-DAMO bacteria increased in response to nitrite exposure. No other bacteria significantly expressed nor genes under these conditions, suggesting n-DAMO bacteria are responsible for N2O being produced. In a 35-day bioreactor experiment, N2O produced by the n-DAMO bacteria accumulated when nitrite was in excess; this was found to be up to 3.2% of the nitrogen that resulted from nitrite removal. Together, these results suggested that excess nitrite is an important driver of N2O production by n-DAMO bacteria. To this end, proper monitoring and control of nitrite levels in wastewater treatment plants would be effective strategies for mitigating N2O emissions to the atmosphere.

Fecal calprotectin as an indicator in risk stratification of pouchitis following ileal pouch-anal anastomosis for ulcerative colitis.

BACKGROUND: Pouchitis is the most common complication following restorative proctocolectomy and ileal pouch-anal anastomosis (IPAA) for ulcerative colitis (UC). Fecal calprotectin (FC) is a noninvasive indicator of the intestinal inflammatory status. This study was conducted to evaluate the clinical value of the FC concentration for the diagnosis and risk assessment of pouchitis. PATIENTS AND METHODS: This retrospective study involved patients who underwent IPAA for UC at Tianjin Medical University General Hospital from January 2015 to January 2019. The patients were categorized into pouchitis and non-pouchitis groups based on their Pouchitis Disease Activity Index (PDAI) score. Laboratory indicators, including the FC concentration, were collected from both groups. RESULTS: Sixty-six patients with UC after IPAA were included in the study and divided into the non-pouchitis group (n = 40) and pouchitis group (n = 26). The correlation coefficient between the FC concentration and the PDAI score was 0.651 (p < 0.001). Receiver operating characteristic analysis showed that the FC cut-off value for predicting pouchitis was 579.60 µg/g (area under the curve, 0.938). The patients were then divided into three subgroups according to their PDAI score (0-2, 3-6, and ≥7), and significant differences in the FC concentration were found among the three subgroups. The best FC cut-off value for predicting a high risk of pouchitis (PDAI score of 3-6) was 143.25 µg/g (area under the curve, 0.876). CONCLUSIONS: FC is a useful biomarker in patients with pouchitis. Patients are advised to regularly undergo FC measurement to monitor for pouchitis. An FC concentration in the range of 143.25-579.60 µg/g is predictive of a high risk for pouchitis, and further examination and preventive treatment are necessary in such patients.KEY MESSAGESFecal calprotectin can be used to quantify pouch inflammation.Fecal calprotectin can be used to predict a high risk of pouchitis.

Reactivated biofilm coupling n-DAMO with anammox achieved high-rate nitrogen removal in membrane aerated moving bed biofilm reactor.

As a promising technology, the combination of nitrate/nitrite-dependent anaerobic methane oxidation (n-DAMO) with Anammox offers a solution to achieve effective and sustainable wastewater treatment. However, this sustainable process faces challenges to accumulate sufficient biomass for reaching practical nitrogen removal performance. This study developed an innovative membrane aerated moving bed biofilm reactor (MAMBBR), which supported sufficient methane supply and excellent biofilm attachment, for cultivating biofilms coupling n-DAMO with Anammox. Biofilms were developed rapidly on the polyurethane foam with the supply of ammonium and nitrate, achieving the bioreactor performance of 275 g N m-3 d-1 within 102 days. After the preservation at -20 °C for 8 months, the biofilm was successfully reactivated and achieved 315 g N m-3 d-1 after 188 days. After reactivation, MAMBBR was applied to treat synthetic sidestream wastewater. Up to 99.9% of total nitrogen was removed with the bioreactor performance of 4.0 kg N m-3 d-1. Microbial community analysis and mass balance calculation demonstrated that n-DAMO microorganisms and Anammox bacteria collectively contributed to nitrogen removal in MAMBBR. The MAMBBR developed in this study provides an ideal system of integrating n-DAMO with Anammox for sustainable wastewater treatment.

Design, fabrication, and testing of an all-metal ultra-compact telescope.

The design, fabrication, and testing of an all-metal four-mirror telescope for high-resolution remote sensing is presented in this paper. The system works in the visible (VIS) band and is designed with a focal length of 1406 mm, an aperture of 200 mm, and a full field of view (FOV) of 1.32°. The mechanical structure is designed to realize the snap-together alignment. The primary mirror (M1) and tertiary mirror (M3) are designed as a co-substrate element to simplify the fabrication and alignment. The telescope's weight is 3.5 kg, and the volume is just φ230×220mm3. Metallic mirrors are fabricated with single-point diamond turning, and post-polishing is used to correct the mirror's surface form deviation and remove turning tool marks effectively. After polishing, the RMS value of the mirror surface form deviation of the final mirror can reach 0.02λ at λ=632.8nm, and the surface roughness Ra value is about 1.83 nm. Benefiting from the all-metal mechanical design, the alignment process of the telescope is fast and accurate. The interferometric wavefront, modulation transfer function, and focal length of the telescope are measured, and the results demonstrated that it achieves the near-diffraction-limited imaging performance.

Mainstream Nitrogen and Dissolved Methane Removal through Coupling n-DAMO with Anammox in Granular Sludge at Low Temperature.

Mainstream anaerobic wastewater treatment has received increasing attention for the recovery of methane-rich biogas from biodegradable organics, but subsequent mainstream nitrogen and dissolved methane removal at low temperatures remains a critical challenge in practical applications. In this study, granular sludge coupling n-DAMO with Anammox was employed for mainstream nitrogen removal, and the dissolved methane removal potential of granular sludge at low temperatures was investigated. A stable nitrogen removal rate (0.94 kg N m-3 d-1 at 20 °C) was achieved with a high-level effluent quality (<3.0 mg TN L-1) in a lab-scale membrane granular sludge reactor (MGSR). With decreasing temperature, the nitrogen removal rate dropped to 0.55 kg N m-3 d-1 at 10 °C, while the effluent concentration remained <1.0 mg TN L-1. The granular sludge with an average diameter of 1.8 mm proved to retain sufficient biomass (27 g VSS L-1), which enabled n-DAMO and Anammox activity at a hydraulic retention time as low as 2.16 h even at 10 °C. 16S rRNA gene sequencing and scanning electron microscopy revealed a stable community composition and compact structure of granular sludge during long-term operation. Energy recovery could be maximized by recovering most of the dissolved methane in mainstream anaerobic effluent, as only a small amount of dissolved methane was capable of supporting denitrifying methanotrophs in granular sludge, which enabled high-level nitrogen removal.

A review of quorum sensing improving partial nitritation-anammox process: Functions, mechanisms and prospects.

Partial nitritation-anammox (PNA) is a promising and energy-efficient process for the sustainable nitrogen removal. However, its wide applications are still limited by the long start-up period and instability of long-term operation. Quorum sensing (QS), as a way of cell-to-cell communication generally regulating various microbial behaviors, has been increasingly investigated in PNA process, because QS may substantially manipulate the metabolism of microorganisms and overcome the limitations of PNA process. This critical review provides a comprehensive analysis of QS in PNA systems, and identifies the challenges and opportunities for the optimization of PNA process based on QS. The analysis is grouped based on the configurations of PNA process, including partial nitritation, anammox and single-stage PNA systems. QS is confirmed to regulate various properties of PNA systems, including microbial activity, microbial growth rate, microbial aggregation, microbial interactions and the robustness under adverse conditions. Major challenges in the mechanisms of QS, such as QS circuits, target genes and the response to environmental inputs, are identified. Potential applications of QS, such as short-term addition of certain acyl-homoserine lactones (AHLs) or substances containing AHLs, transient unfavorable conditions to stimulate the secretion of AHLs, are also proposed. This review focuses on the theoretical and practical cognation for QS in PNA systems, and serves as a stepping stone for further QS-based strategies to enhance nitrogen removal through PNA process.

Adenoid cystic carcinoma of the gastroesophageal junction: A case report.

RATIONALE: Adenoid cystic carcinoma (ACC) rarely occurs in the digestive tract, particularly in the gastroesophageal junction. PATIENT CONCERNS: A 44-year-old male vomiting blood was admitted to our hospital. Endoscopic ultrasound showed a 2.2 × 3.0 cm submucosal tumor in the gastroesophageal junction. DIAGNOSIS: According to the histopathological examination, the tumor was composed predominantly of ductal epithelial and myoepithelial cells. Immunohistochemical staining revealed that the tumor expressed cytokeratin, cluster of differentiation 117, p63, and calponin. Based on these findings, ACC was diagnosed. INTERVENTIONS: Endoscopic submucosal dissection (ESD) was performed to remove the tumor. As the margins of the ESD specimen were positive, the patient underwent total gastrectomy with D2 lymphadenectomy. Finally, neither residual tumor nor lymphatic metastasis was detected in the surgical specimens. OUTCOMES: No sign of recurrence has been detected during 36 months of follow-up as of October 2018. LESSONS: ESD may be an alternative treatment for cardial ACC invading the submucosa.

Solitary fibrous tumor of small bowel mesentery with postoperative bowel obstruction: a case report and review of literature.

Solitary fibrous tumor (SFT) which is an extremely rare clinical entity has been reported infrequently. Most commonly it is distinguished into pleural and extrapleural forms, with same morphological resemblance. There has been many literatures reported regarding extrapleural form of SFT but few cases of SFT originating from small bowel mesentery have been reported till now. We here report one case of SFT of small bowel mesentery with some eventful postoperative bowel obstruction and literature review.

[The effect of pro-angiogenic factors and their receptors on angiogenesis in hepatocellular carcinoma].

OBJECTIVE: To explore the effect of pro-angiogenic factors and their receptors on angiogenesis in hepatocellular carcinoma. METHODS: Expression of VEGF/KDR and Angiopoietins/Tie2 was detected by RT-PCR and Western blot in 15 cases with hepatocellular carcinoma, 15 tumor adjacent tissues (<1 cm, >5 cm), 8 cirrhotic liver, and 4 normal liver. Immunohistochemistry (IHC) was used to detect CD34 expression, and the relationship between neovascular density and angiogenesis was analyzed. RESULTS: The expression levels of VEGF and Ang2 were significantly higher in hepacellular carcinoma group than those in the other groups (P < 0.01), and so did the expression of CD34. The expressions of KDR and Ang1/Tie2 showed no significant difference in all groups, but they indeed increased to various levels in tumor and tumor adjacent tissues as compared with those in cirrhosis and normal liver. CONCLUSION: VEGF/KDR and Angiopoietins/Tie2 may be the crucial signal pathways in the development of hepatocellular carcinoma.

Suppressing progress of pancreatitis through selective inhibition of NF-KappaB activation by using NAC.

OBJECTIVE: To explore the characteristics of NF-KappaB activation in the progress of pancreatitis, the relationship with expression of TNF-alpha in the inflammatory reaction, and prevent the exacerbation of pancreatitis by using NAC. METHOD: Forty-eight rats were divided into three groups: therapy (group C), pancreatitis (group B) and control (group A). NAC served as the inhibitor of NF-KappaB activation. In the time intervals of 1.5, 3.0, 6.0, 12.0 hour, NF-KappaB activation was detected with flow cytometry (FCM) and the expression of TNF-alpha mRNA and protein with in situ hybridization (ISH) and enzyme-linked immuno-sorbent assay (ELISA) respectively. Meanwhile, the level of lipase and amylase in the serum was assayed and the pathological change was evaluated. RESULT: NF-KappaB activation in the pancreatitis group was higher than that in the control group (P<0.01), peaked at 3 hours, and was depressed by the inhibitor of NF-KappaB, NAC. The expression of TNF-alpha as well as the level of lipase and amylase in the serum also rose synchronously with activation of NF-KappaB. In contrast to group A, it was significantly different (P<0.01) in group B. After using NAC in group C, all of these values were decreased and the inflammatory reaction in the pancreas abated evidently. The pathology changes of the pancreas were shown to be alleviated in group C. CONCLUSION: First, NF-KappaB activity is intensively initiated in the course of pancreatitis and shown to have closely relationship with the release of cytokines. Second, use of NAC markedly depressed NF-KappaB activation. TNF-alpha expression is down regulated by cytokines. It is suggested that NAC probably acts as a useful agent for treatment of pancreatitis by indirectly inhibiting activation of NF-KappaB.

Expression of co-stimulator 4-1BB molecule in hepatocellular carcinoma and adjacent non-tumor liver tissue, and its possible role in tumor immunity.

AIM: To investigate the expression of 4-1BB molecule in hepatocellular carcinoma (HCC) and its adjacent tissues. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) was used to determine the gene expression of 4-1BB in hepatocarcinoma and its adjacent tissues, and peripheral blood mononuclear cells (PBMCs) from both HCC and health control groups. Flow cytometry was used to analyse the phenotypes of T cell subsets from the blood of HCC patients and healthy volunteers, and further to determine whether 4-1BB molecules were also expressed on the surface of CD4+ and CD8+ T cells. The localization of 4-1BB proteins on tumor infiltrating T cells was determined by direct immunofluorescence cytochemical staining and detected by confocal microscopy. RESULTS: 4-1BB mRNA, which was not detectable in normal liver, was found in 19 liver tissues adjacent to tumor edge (<1.0 cm). Low expression of 4-1BB mRNA was shown in 8 tumor tissues and 6 liver tissues located within 1 to 5 cm away from tumor edge. In PBMCs, 4-1BB mRNA was almost not detected. Percentage of CD4+, CD8+ and CD3+/CD25+ T cells, as well as ratio of CD4 to CD8 revealed no difference between groups (P>0.05, respectively), while a significant lower percentage of CD3+ T cell was found in HCC group as compared to healthy control group (P<0.05). However, 4-1BB molecules were almost not found on the surface of CD4+ and CD8+ T cells in HCC and healthy control group. Double-staining of 4-1BB+/CD4+ and 4-1BB+/CD8+ immunofluorescence on tumor infiltrating T cells was detected in 13 liver tissues adjacent to tumor edge (<1.0 cm) by confocal microscopy. CONCLUSION: Although HCC may escape from immune attack by weak immunogenicity or downregulated expression of MHC-1 molecules on the tumor cell surface, tumor infiltrating T cells can be activated via other costimulatory signal pathways to exert a limited antitumor effect on local microenvironment. The present study also implicates that modulating 4-1BB/4-1BBL costimulatory pathway may be an effective immunotherapy strategy to augment the host response.

The molecular mechanism underlying angiogenesis in hepatocellular carcinoma: the imbalance activation of signaling pathways.

OBJECTIVE: To explore the effect of two dominating signaling pathways, VEGF/KDR and angiopoietins/Tie2, on the formation of new blood vessel in hepatocellular carcinoma (HCC) growth and metastasis. METHODS: RT-PCR and Western blot were employed to evaluate the VEGF/KDR and angiopoietins/Tie2 expression in samples from 23 patients with HCC. Meanwhile, microvessel density (MVD) was determined as a marker of angiogenesis by counting CD34 positive cells with the method of immunohistochemistry. RESULTS: The two pathways were activated in all HCC samples. The expressions of vascular endothelial growth factor (VEGF) and angiopoietin-2 (Ang2) were significantly higher (P<0.05) in hepatocellular carcinoma tissues and the margin of the tumor than those in control groups, and so did CD34 positive cells. Although significant difference in the expression of kinase insert domain containing receptor (KDR) and Ang1/Tie2 was not observed in all groups, their distinct high levels were seen in hepatoma and its margin compared with normal and cirrhotic liver. VEGF and Ang2 expressions were seen up-regulated in HCC with vascular invasion and satellite lesion. CONCLUSIONS: The two signaling pathways, VEGF/KDR and angiopoietins/Tie2 are activated in the process of angiogenesis in HCC and modulate the formation of new blood vessels. The imparity of the two signaling pathways' activation is to benefit HCC metastasis. In the two pathways, VEGF and Ang2 may play an important role in the process of angiogenesis, and are necessary indicators for the prognosis and metastasis of HCC. This study provides another clue for the exploration of anti-angiogenic agents.

Expression of 4-1BB molecule on peripheral blood T cells in liver transplanted patients and its clinical implication.

OBJECTIVE: To investigate the gene expression of 4-1BB in peripheral blood mononuclear cells (PBMCs) and its possible significance in clinical liver transplantation. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) was used to determine the gene expression of 4-1BB in PBMCs from 22 patients receiving liver transplantation, 13 patients with primary liver carcinoma (PLC), and 12 healthy controls. To determine whether 4-1BB molecule is also expressed on the surface of CD4+ and CD8+ T cell, flow cytometry was used to analyse the phenotype of T cell subsets from the blood of liver transplantation patients. RESULTS: 4-1BB mRNA was detected in PBMCs from stable survivors after liver transplantation, but almost not detected in PBMCs from PLC patients and healthy controls. Meanwhile, 4-1BB was almost not expressed on the surface of CD4+ and CD8+T cells in healthy controls and PLC patients. A low level of 4-1BB expression, however, was found on the surface of CD4+ and CD8+ T cells from the stable survivors after liver transplantation. CONCLUSIONS: This study demonstrates that although patients are stable after liver transplantation, effector T-cells can also be activated through the signal of 4-1BB molecule and persistent immune response to grafts. Blockage of 4-1BB/4-1BBL pathway may benefitially reduce the clinical dosage of immunosuppressive agents and prolong the survival of grafts.

[The effect of activated nuclear factor-kappaB in pathogenesis of acute pancreatitis].

OBJECTIVE: To explore the effect of the activated NF-kappaB and the interaction between activated NF-kappaB and tumor necrosis factor (TNF)-alpha in the process of acute pancreatitis. METHODS: 64 Wistar rats were randomly divided into two groups of 32 rats: pancreatitis group (to be made pancreatitis models) and control group. 1.5, 3.0, 6.0, and 12.0 hours after the onset of experiment the amount of ascitic fluid was measured, blood was extracted from abdominal aorta, changes of pancreas was observed, pancreatic tissues were stained with HE, and flow cytometry (FCM) and enzyme linked immuno-sorbent assay (ELISA) were used to examine the content of TNF-alpha protein and activation of NF-kappaB (number of positive cells/50 micro l) in the pancreatic tissues. The contents of amylase and lipase in plasma were examined. The pathology of pancreatic tissue was graded. RESULTS: The levels of activated NF-kappaB and TNF-alpha protein in the pancreatic tissue were all significantly higher than those of the control group at any time point (all P < 0.05). The levels of activation of NF-kappaB of the pancreatitis group at any time point were significantly higher than those of the control group (all P < 0.01) and reached its maximum about 3.0 hours after the onset of experiment and then declined. The levels of plasma amylase and lipase were significantly higher in the pancreatic group than in the control group at any rime point. (all P < 0.01). In the pancreatic group severe edema and congestion were found at the 3.0 h time point and bleeding and necrosis were found at the 6.0-hour time point. CONCLUSION: Activated NF-kappaB as initial factor plays an important role in the pathogenesis of acute pancreatitis, activates a lot of inflammatory media, and induces cascading reaction of inflammation. TNF-alpha is a pivotal factor in pancreatitis pathogenesis, it cooperates with amylase and lipase to intensify the leisure in pancreatic tissue resulting bleeding and necrosis.