Capsaicin mitigates ventilator-induced lung injury by suppressing ferroptosis and maintaining mitochondrial redox homeostasis through SIRT3-dependent mechanisms.

BACKGROUND: Ventilator-induced lung injury (VILI) is one of the severe complications in the clinic concerning mechanical ventilation (MV). Capsaicin (CAP) has anti-inflammatory and inhibitory effects on oxidative stress, which is a significant element causing cellular ferroptosis. Nevertheless, the specific role and potential mechanistic pathways through which CAP modulates ferroptosis in VILI remain elusive. METHODS: VILI was established in vivo, and the pulmonary epithelial cell injury model induced by circulation stretching (CS) was established in vitro. Both mice and cells were pretreated with CAP. Transmission electron microscopy, ELISA, Western blot, immunofluorescence, RT-PCR, fluorescent probes, and other experimental methods were used to clarify the relationship between iron death and VILI in alveolar epithelial cells, and whether capsaicin alleviates VILI by inhibiting iron death and its specific mechanism. RESULTS: Ferroptosis was involved in VILI by utilizing in vivo models. CAP inhibited ferroptosis and alleviated VILI's lung damage and inflammation, and this protective effect of CAP was dependent on maintaining mitochondrial redox system through SITR3 signaling. In the CS-caused lung epithelial cell injury models, CAP reduced pathological CS-caused ferroptosis and cell injury. Knockdown SIRT3 reversed the role of CAP on the maintaining mitochondria dysfunction under pathological CS and eliminated its subsequent advantageous impacts for ferroptosis against overstretching cells. CONCLUSION: The outcomes showed that CAP alleviated ferroptosis in VILI via improving the activity of SITR3 to suppressing mitochondrial oxidative damage and maintaining mitochondrial redox homeostasis, illustrating its possibility as a novel therapeutic goal for VILI.

Role of PI3K/AKT signaling pathway involved in self-renewing and maintaining biological properties of chicken primordial germ cells.

Avian primordial germ cells (PGCs) are important culture cells for the production of transgenic chickens and preservation of the genetic resources of endangered species; however, culturing these cells in vitro proves challenging. Although the proliferation of chicken PGCs is dependent on insulin, the underlying molecular mechanisms remain unclear. In the present study, we explored the expression of the PI3K/AKT signaling pathway in PGCs, investigated its effects on PGC self-renewal and biological properties, and identified the underlying mechanisms. Our findings indicated that although supplementation with the PI3K/AKT activator IGF-1 failed to promote proliferation under the assessed culture conditions, the PI3K/AKT inhibitor LY294002 resulted in retarded cell proliferation and reduced expression of germ cell-related markers. We further demonstrated that inhibition of PI3K/AKT regulates the cell cycle and promotes apoptosis in PGCs by activating the expression of BAX and inhibiting that of Bcl-2. These findings indicated that the PI3K/AKT pathway is required for cell renewal, apoptosis, and maintenance of the reproductive potential in chicken PGCs. This study aimed to provide a theoretical basis for the optimization and improvement of a culture system for chicken PGCs and provide insights into the self-renewal of vertebrate PGCs as well as potential evolutionary changes in this unique cell population.

Evaluating extractable work of quantum batteries via entropic uncertainty relations.

In this study, we investigate the effectiveness of entropic uncertainty relations (EURs) in discerning the energy variation in quantum batteries (QBs) modelled by battery-charger field in the presence of bosonic and fermionic reservoirs. Our results suggest that the extractable works (exergy and ergotropy) have versatile characteristics in different scenarios, resulting in a complex relationship between tightness and extractable work. It is worth noting that the tightness of the lower bound of entropic uncertainty can be a good indicator for energy conversion efficiency in charging QBs. Furthermore, we disclose how the EUR including uncertainty and lower bound contributes to energy conversion efficiency in the QB system. It is believed that these findings will be beneficial for better understanding the role of quantum uncertainty in evaluating quantum battery performance.

High-intensity interval training improves hypothalamic inflammation by suppressing HIF-1α signaling in microglia of male C57BL/6J mice.

Repeated bouts of high-intensity interval training (HIIT) induce an improvement in metabolism via plasticity of melanocortin circuits and attenuated hypothalamic inflammation. HIF-1α, which plays a vital role in hypothalamus-mediated regulation of peripheral metabolism, is enhanced in the hypothalamus by HIIT. This study aimed to investigate the effects of HIIT on hypothalamic HIF-1α expression and peripheral metabolism in obese mice and the underlying molecular mechanisms. By using a high-fat diet (HFD)-induced obesity mouse model, we determined the effect of HIIT on energy balance and the expression of the hypothalamic appetite-regulating neuropeptides, POMC and NPY. Moreover, hypothalamic HIF-1α signaling and its downstream glycolytic enzymes were explored after HIIT intervention. The state of microglia and microglial NF-κB signaling in the hypothalamus were also examined in vivo. In vitro by using an adenovirus carrying shRNA-HIF1ß, we explored the impact of HIF-1 signaling on glycolysis and NF-κB inflammatory signaling in BV2 cells. Food intake was suppressed and whole-body metabolism was improved in exercised DIO mice, accompanied by changes in the expression of POMC and NPY. Moreover, total and microglial HIF-1α signaling were obviously attenuated in the hypothalamus, consistent with the decreased levels of glycolytic enzymes. Both HFD-induced microglial activation and hypothalamic NF-κB signaling were significantly suppressed following HIIT in vivo. In BV2 cells, after HIF-1 complex knockdown, glycolysis and NF-κB inflammatory signaling were significantly attenuated. The data indicate that HIIT improves peripheral metabolism probably via attenuated HFD-induced microglial activation and microglial NF-κB signaling in the hypothalamus, which could be mediated by suppressed microglial HIF-1α signaling.

The cross-sectional correlation between the oxidative balance score and cardiometabolic risk factors and its potential correlation with longitudinal mortality in patients with cardiometabolic risk factors.

BACKGROUND: This study analyzes the correlation between oxidative balance score (OBS), cardiometabolic risk factors (CMRFs), and mortality in individuals with CMRFs. METHODS: Data were chosen from the National Health and Nutrition Examination Survey. The survey-weighted multivariable logistic regression models were implemented to explore the relationship between OBS and the risk of CMRFs. Then, Cox proportional hazard models were employed to estimate the impact of OBS on mortality in individuals with CMRFs. RESULTS: Following multivariate adjustment, the subjects in the highest quartile exhibited a 46% reduction in the risk of CMRFs, a 33% reduction in the risk of diabetes, a 31% reduction in the risk of hypertension, and a 36% reduction in the risk of hyperlipidemia, compared with those in the lowest quartile. Furthermore, each 1-unit increase in OBS was remarkably negatively correlated with the prevalence of CMRFs, diabetes, hypertension, and hyperlipidemia. The correlation between OBS and CMFRs was found to be mediated by serum γ-glutamyltransferase (GGT) and white blood cells (WBC), and the mediation effect of GGT levels and WBC, accounting for 6.90% and 11.51%, respectively. Lastly, the multivariate Cox regression model revealed that elevated OBS, irrespective of whether it was treated as a categorical or continuous variable, exhibited a significant association with decreased mortality from all causes, cardiovascular disease, and cancer. CONCLUSIONS: An increased OBS might reflect a lower risk of CMRFs and a favorable prognosis for individuals with CMRFs. Moreover, WBC and GGT may play a potential mediating role between OBS and CMRFs.

UPLC-ESI-MS/MS-based widely targeted metabolomics reveals differences in metabolite composition among four Ganoderma species.

The Chinese name "Lingzhi" refers to Ganoderma genus, which are increasingly used in the food and medical industries. Ganoderma species are often used interchangeably since the differences in their composition are not known. To find compositional metabolite differences among Ganoderma species, we conducted a widely targeted metabolomics analysis of four commonly used edible and medicinal Ganoderma species based on ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometry. Through pairwise comparisons, we identified 575-764 significant differential metabolites among the species, most of which exhibited large fold differences. We screened and analyzed the composition and functionality of the advantageous metabolites in each species. Ganoderma lingzhi advantageous metabolites were mostly related to amino acids and derivatives, as well as terpenes, G. sinense to terpenes, and G. leucocontextum and G. tsugae to nucleotides and derivatives, alkaloids, and lipids. Network pharmacological analysis showed that SRC, GAPDH, TNF, and AKT1 were the key targets of high-degree advantage metabolites among the four Ganoderma species. Analysis of Gene Ontology and Kyoto Encyclopedia of Genes and Genomes demonstrated that the advantage metabolites in the four Ganoderma species may regulate and participate in signaling pathways associated with diverse cancers, Alzheimer's disease, and diabetes. Our findings contribute to more targeted development of Ganoderma products in the food and medical industries.

Rational Design of PARP1/c-Met Dual Inhibitors for Overcoming PARP1 Inhibitor Resistance Induced by c-Met Overexpression.

The emergence of resistance to PARP1 inhibitors poses a current therapeutic challenge, necessitating the development of novel strategies to overcome this obstacle. The present study describes the design and synthesis of a series of small molecules that target both PARP1 and c-Met. Among them, compound 16 is identified as a highly potent dual inhibitor, exhibiting excellent inhibitory activities against PARP1 (IC50 = 3.3 nM) and c-Met (IC50 = 32.2 nM), as well as demonstrating good antiproliferative effects on HR-proficient cancer cell lines and those resistant to PARP1 inhibitors. Importantly, compound 16 demonstrates superior antitumor potency compared to the PARP1 inhibitor Olaparib and the c-Met inhibitor Crizotinib, either alone or in combination, in MDA-MB-231 and HCT116OR xenograft models. These findings highlight the potential of PARP1/c-Met dual inhibitors for expanding the indications of PARP1 inhibitors and overcoming tumor cells' resistance to them.

Clinical and molecular characteristics of RNF43 mutations as promising prognostic biomarkers in colorectal cancer.

Background: Transmembrane E3 ubiquitin ligase (RNF43) mutations are present in approximately 6-18% of colorectal cancers (CRC) and could enhance Wnt/ß-catenin signaling, which is emerging as a promising therapeutic target. This study aims to investigate the clinical and molecular characteristics and potential heterogeneity of RNF43-mutant CRC. Methods: A total of 78 patients with RNF43-mutant CRC were enrolled from July 2013 to November 2022. Demographic data, clinical characteristics, treatment regimens used, and survival outcomes were collected and analyzed. Results: Our study uncovered that patients with RNF43 mutations in the N-terminal domain (NTD; n = 50) exhibited shorter overall survival (OS; median months, 50.80 versus not reached; p = 0.043) compared to those in the C-terminal domain (CTD; n = 17). Most RNF43 mutations in NTD had positive primary lymph node status, low tumor mutation burden (TMB-L), and correlated with proficient mismatch repair (pMMR)/microsatellite stable (MSS) status. By contrast, RNF43 mutations in CTD were significantly enriched in deficient MMR (dMMR)/microsatellite instability (MSI-H) tumors with high TMB (TMB-H). N-terminal RNF43-mutated tumors harbored a hotspot variant (RNF43 R117fs), which independently predicted a significantly worse outcome in pMMR/MSS CRC with a median OS of 18.9 months. Patients with RNF43 mutations and the BRAF V600E alterations demonstrated sensitivity to BRAF/EGFR inhibitors. Moreover, we observed that pMMR/MSS patients with RNF43 R117fs mutation had a higher incidence of stage IV, ⩾2 metastatic sites, low TMB, and none of them received PD-1/PD-L1 inhibitor therapy. Conclusion: Our findings provide the first evidence that RNF43 mutations in NTD and the R117fs variant correlate with a poorer prognosis in CRC patients, providing strategies for Wnt-targeted therapy to improve clinical efficacy.

DCLK1 and its oncogenic functions: A promising therapeutic target for cancers.

Doublecortin-like kinase 1 (DCLK1), a significant constituent of the protein kinase superfamily and the doublecortin family, has been recognized as a prooncogenic factor that exhibits a strong association with the malignant progression and clinical prognosis of various cancers. DCLK1 serves as a stem cell marker that governs tumorigenesis, tumor cell reprogramming, and epithelial-mesenchymal transition. Multiple studies have indicated the capable of DCLK1 in regulating the DNA damage response and facilitating DNA damage repair. Additionally, DCLK1 is involved in the regulation of the immune microenvironment and the promotion of tumor immune evasion. Recently, DCLK1 has emerged as a promising therapeutic target for a multitude of cancers. Several small-molecule inhibitors of DCLK1 have been identified. Nevertheless, the biological roles of DCLK1 are mainly ambiguous, particularly with the disparities between its α- and ß-form transcripts in the malignant progression of cancers, which impedes the development of more precisely targeted drugs. This article focuses on tumor stem cells, tumor epithelial-mesenchymal transition, the DNA damage response, and the tumor microenvironment to provide a comprehensive overview of the association between DCLK1 and tumor malignant progression, address unsolved questions and current challenges, and project future directions for targeting DCLK1 for the diagnosis and treatment of cancers.

SH2D4A inhibits esophageal squamous cell carcinoma progression through FAK/PI3K/AKT signaling pathway.

Esophageal squamous cell carcinoma (ESCC), one of the most common malignant tumors, is now afflicting approximately 80% of patients diagnosed with esophageal cancers. The therapeutic effect and prognosis of ESCC remain inadequate due to the unusual early symptoms and rapid malignant progression. SH2 Domain containing 4 A (SH2D4A) is downregulated in malignancies and is closely associated with tumor progression. However, neither the biological functions nor the fundamental mechanisms of SH2D4A on ESCC are known. In this study, it was found that SH2D4A is downregulated in ESCC tissues and cell lines. Incorporating immunohistochemistry and clinicopathological findings, we determined that decreased SH2D4A expression was substantially associated with adverse clinical outcomes. Overexpression of SH2D4A inhibited cell proliferation and migration, whereas suppressing SH2D4A has the opposite effect. SH2D4A mechanistically inhibited cells from proliferating and migrating through the FAK/PI3K/AKT signaling pathway. Furthermore, the results of xenograft tumor growth confirmed the preceding findings. In conclusion, our findings reveal that SH2D4A is a gene which can serve as a cancer suppressor in ESCC and may inhibits the ESCC progression by interfering with the FAK/PI3K/AKT signaling pathway. SH2D4A could act as a target for diagnostic or therapeutic purpose in ESCC.

Efficacy and safety of injection of hyaluronic acid filler VYC-20L in facial rejuvenation / 中华医学美学美容杂志

Objective:To explore the efficacy and safety of hyaluronic acid filler VYC-20L for full-face lifting in aesthetic seeking patients.Methods:Between November 2020 and November 2021, a total of 216 aesthetic seeking patients were enrolled in Shanghai Chingho Outpatient Department, World Path Clinic International, Qihe Medical Beauty Hospital and Qinhuangdao Qiaozhi Beauty Hospital, including 37 males and 179 females, aged 25-67 (41.42±10.93) years. According to the needs and requirements, the novel injection technique of " ROYGBbP-rainbow lifting method" was used to inject hyaluronic acid filler VYC-20L. The global aesthetic improvement scale (GAIS) and the treatment satisfaction questionnaires were scored and evaluated before the injection, and at follow-up visits 1, 6, and 12 months after the injection. Any adverse reaction or adverse events presenting or reported by the patients post-injection were recorded.Results:At 1 month, 6 months and 12 months after the injection, about 203 (94.0%), 208 (96.3%) and 205 (94.9%) of the aesthetic seeking patients rated their full-face appearance as " excellently improved" or " much improved" on the GAIS, respectively. And 12 months after the injection, the overall facial satisfaction scores and appearance recognition scores of all aesthetic seeking patients were all significantly higher than those before injection ( P<0.01). 197 (91.2%), 198 (91.7%) and 198 (91.7%) of the aesthetic seeking patients were " very satisfied" or " relatively satisfied" with the treatment at 1 month, 6 months and 12 months, respectively. Treatment site responses most frequently reported were tenderness, bruising, topical swelling and skin redness. Most of the symptoms were moderate or mild feeling, lasting for no more than two weeks. Conclusions:The application of hyaluronic acid filler VYC-20L is safe and effective for full-face lifting in aesthetic seeking patients, which can significantly improve facial sagging and rejuvenate the face. The effect of improvements can last for 12 months.

Effect of Proinflammatory S100A9 Protein on Migration and Proliferation of Microglial Cells.

Alzheimer's disease (AD) is a multifactorial disease affecting aging population worldwide. Neuroinflammation became a focus of research as one of the major pathologic processes relating to the disease onset and progression. Proinflammatory S100A9 is the central culprit in the amyloid-neuroinflammatory cascade implicated in AD and other neurodegenerative diseases. We studied the effect of S100A9 on microglial BV-2 cell proliferation and migration. The responses of BV-2 cells to S100A9 stimulation were monitored in real-time using live cell microscopy, transcriptome sequencing, immunofluorescence staining, western blot analysis, and ELISA. We observed that a low dose of S100A9 promotes migration and proliferation of BV-2 cells. However, acute inflammatory condition (i.e., high S100A9 doses) causes diminished cell viability; it is uncovered that S100A9 activates TLR-4 and TLR-7 signaling pathways, leading to TNF-α and IL-6 expression, which affect BV-2 cell migration and proliferation in a concentration-dependent manner. Interestingly, the effects of S100A9 are not only inhibited by TNF-α and IL-6 antibodies. The addition of amyloid-ß (Aß) 1-40 peptide resumes the capacities of BV-2 cells to the level of low S100A9 concentrations. Based on these results, we conclude that in contrast to the beneficial effects of low S100A9 dose, high S100A9 concentration leads to impaired mobility and proliferation of immune cells, reflecting neurotoxicity at acute inflammatory conditions. However, the formation of Aß plaques may be a natural mechanism that rescues cells from the proinflammatory and cytotoxic effects of S100A9, especially considering that inflammation is one of the primary causes of AD.

Effects of Insulin on Proliferation, Apoptosis, and Ferroptosis in Primordial Germ Cells via PI3K-AKT-mTOR Signaling Pathway.

Primordial germ cells (PGCs) are essential for the genetic modification, resource conservation, and recovery of endangered breeds in chickens and need to remain viable and proliferative in vitro. Therefore, there is an urgent need to elucidate the functions of the influencing factors and their regulatory mechanisms. In this study, PGCs collected from Rugao yellow chicken embryonic eggs at Day 5.5 were cultured in media containing 0, 5, 10, 20, 50, and 100 µg/mL insulin. The results showed that insulin regulates cell proliferation in PGCs in a dose-dependent way, with an optimal dose of 10 µg/mL. Insulin mediates the mRNA expression of cell cycle-, apoptosis-, and ferroptosis-related genes. Insulin at 50 µg/mL and 100 µg/mL slowed down the proliferation with elevated ion content and GSH/oxidized glutathione (GSSG) in PGCs compared to 10 µg/mL. In addition, insulin activates the PI3K/AKT/mTOR pathway dose dependently. Collectively, this study demonstrates that insulin reduces apoptosis and ferroptosis and enhances cell proliferation in a dose-dependent manner via the PI3K-AKT-mTOR signaling pathway in PGCs, providing a new addition to the theory of the regulatory role of the growth and proliferation of PGC in vitro cultures.

Design, synthesis and biological evaluation of novel DCLK1 inhibitor containing purine skeleton for the treatment of pancreatic cancer.

Pancreatic cancer is a highly lethal form of malignancy that continues to pose a significant and unresolved health challenge. Doublecortin-like kinase 1 (DCLK1), a serine/threonine kinase, is found to be overexpressed in pancreatic cancer and holds promise as a potential therapeutic target for this disease. However, few potent inhibitors have been reported currently. Herein, a series of novel purine, pyrrolo [2,3-d]pyrimidine, and pyrazolo [3,4-d] pyrimidine derivatives were designed, synthesized, and evaluated their biological activities in vitro. Among them, compound I-5 stood out as the most potent compound with strong inhibitory activity against DCLK1 (IC50 = 171.3 nM) and remarkable antiproliferative effects on SW1990 cell lines (IC50 = 0.6 µM). Notably, I-5 exhibited higher in vivo antitumor potency (Tumor growth inhibition value (TGI): 68.6 %) than DCLK1-IN-1 (TGI: 24.82 %) in the SW1990 xenograft model. The preliminary mechanism study demonstrated that I-5 not only inhibited SW1990 cell invasion and migration, but also decreased the expression of prominin-1 (CD133) and cluster of differentiation 44 (CD44), which are considered as differentiation markers for SW1990 stem cells. All the results indicated that I-5, a novel DCLK1 inhibitor, shows promise for further investigation in the treatment of pancreatic cancer.

Association of Magnesium Depletion Score With Cardiovascular Disease and Its Association With Longitudinal Mortality in Patients With Cardiovascular Disease.

Background Dietary magnesium and serum magnesium play an important part in cardiovascular disease (CVD). However, the association between magnesium depletion score (MDS) and CVD development and prognosis remains unclear. This analysis examines the cross-sectional relationship between MDS and CVD, and the longitudinal association between MDS and all-cause and CVD mortality in individuals with CVD. Methods and Results In all, 42 711 individuals were selected from the National Health and Nutrition Examination Survey, including 5015 subjects with CVD. The association between MDS and total and individual CVDs was examined using the survey-weighted multiple logistic regression analysis. Among 5011 patients with CVD, 2285 and 927 participants were recorded with all-cause and CVD deaths, respectively. We applied survey-weighted Cox proportional hazards regression analyses to investigate the impact of MDS on the mortality of individuals with CVD. The CVD group had higher MDS levels than the non-CVD groups. After controlling all confounding factors, individuals with MDS of 2 and ≥3 had higher odds of total CVD and specific CVD than those with MDS of 0. Besides, each 1-unit increase in MDS was strongly related to the risk of total CVD and specific CVD. The relationship between MDS and total CVD was stable and significant in all subgroups. The fully adjusted Cox regression model indicated that high MDS, irrespective of MDS as a categorical or continuous variable, was significantly associated with an elevated risk of all-cause and CVD deaths. Conclusions MDS is a vital risk factor for the prevalence and mortality of individuals with CVD.

Anti-reflux effects of a novel esophagogastric asymmetric anastomosis technique after laparoscopic proximal gastrectomy.

BACKGROUND: Reflux esophagitis is a common postoperative complication of proximal gastrectomy. There is an urgent need for a safer method of performing esophageal-gastric anastomosis that reduces the risk of reflux after proximal gastrectomy. We hypothesize that a novel technique termed esophagogastric asymmetric anastomosis (EGAA) can prevent postoperative reflux in a safe and feasible manner. AIM: To observe a novel method of EGAA to prevent postoperative reflux. METHODS: Initially, we employed a thermal stress computer to simulate and analyze gastric peristalsis at the site of an esophagogastric asymmetric anastomosis. This was done in order to better understand the anti-reflux function and mechanism. Next, we performed digestive tract reconstruction using the EGAA technique in 13 patients who had undergone laparoscopic proximal gastrectomy. Post-surgery, we monitored the structure and function of the reconstruction through imaging exams and gastroscopy. Finally, the patients were followed up to assess the efficacy of the anti-reflux effects. RESULTS: Our simulation experiments have demonstrated that the clockwise contraction caused by gastric peristalsis and the expansion of the gastric fundus caused by the increase of intragastric pressure could significantly tighten the anastomotic stoma, providing a means to prevent the reverse flow of gastric fluids. Thirteen patients with esophagogastric junction tumors underwent laparoscopic proximal gastrectomy, with a mean operation time of 304.2 ± 44.3 min. After the operation, the upper gastroenterography in supine/low head positions showed that eight patients exhibited no gastroesophageal reflux, three had mild reflux, and two had obvious reflux. The abdominal computed tomography examination showed a valve-like structure at the anastomosis. During follow-up, gastroscopy revealed a closed valve-like form at the anastomosis site without stenosis or signs of reflux esophagitis in 11 patients. Only two patients showed gastroesophageal reflux symptoms and mild reflux esophagitis and were treated with proton pump inhibitor therapy. CONCLUSION: EGAA is a feasible and safe surgical method, with an excellent anti-reflux effect after proximal gastrectomy.

Decoupling the simultaneous effects of NO2-, pH and free nitrous acid on N2O and NO production from enriched nitrifying activated sludge.

In the pursuit of energy and carbon neutrality, nitrogen removal technologies have been developed featuring nitrite (NO2-) accumulation. However, high NO2- accumulations are often associated with stimulated greenhouse gas (i.e., nitrous oxide, N2O) emissions. Furthermore, the coexistence of free nitrous acid (FNA) formed by NO2- and proton (pH) makes the consequence of NO2- accumulation on N2O emissions complicated. The concurrent three factors, NO2-, pH and FNA may play different roles on N2O and nitric oxide (NO) emissions simultaneously, which has not been systematically studied. This study aims to decouple the effects of NO2- (0-200 mg N/L), pH (6.5-8) and FNA (0-0.15 mg N/L) on the N2O and NO production rates and the production pathways by ammonia oxidizing bacteria (AOB), with the use of a series of precisely executed batch tests and isotope site-preference analysis. Results suggested the dominant factors affecting the N2O production rate were NO2- and FNA concentrations, while pH alone played a relatively insignificant role. The most influential factor shifted from NO2- to FNA as FNA concentrations increased from 0 to 0.15 mg N/L. At concentrations below 0.0045 mg HNO2-N/L, nitrite rather than FNA played a significant role stimulating N2O production at elevated nitrite concentrations. The inhibition effect of FNA emerged with further increase of FNA between 0.0045-0.015 mg HNO2-N/L, weakening the promoting effect of increased nitrite. While at concentrations above 0.015 mg HNO2-N/L, FNA inhibited N2O production especially from nitrifier denitrification pathway with the level of inhibition linearly correlated with the FNA concentration. pH and the nitrite concentration regulated the production pathways, with elevated pH promoting the nitrifier nitrification pathway, while elevated NO2- concentrations promoting the nitrifier denitrification pathway. In contrast to N2O, NO emission was less susceptible to FNA at concentrations up to 0.015 mg N/L but was stimulated by increasing NO2- concentrations. This study, for the first time, distinguished the effects of pH, NO2- and FNA on N2O and NO production, thereby providing support to the design and operation of novel nitrogen removal systems with NO2- accumulation.

Module walking using an SH3-like cell-wall-binding domain leads to a new GH184 family of muramidases.

Muramidases (also known as lysozymes) hydrolyse the peptidoglycan component of the bacterial cell wall and are found in many glycoside hydrolase (GH) families. Similar to other glycoside hydrolases, muramidases sometimes have noncatalytic domains that facilitate their interaction with the substrate. Here, the identification, characterization and X-ray structure of a novel fungal GH24 muramidase from Trichophaea saccata is first described, in which an SH3-like cell-wall-binding domain (CWBD) was identified by structure comparison in addition to its catalytic domain. Further, a complex between a triglycine peptide and the CWBD from T. saccata is presented that shows a possible anchor point of the peptidoglycan on the CWBD. A `domain-walking' approach, searching for other sequences with a domain of unknown function appended to the CWBD, was then used to identify a group of fungal muramidases that also contain homologous SH3-like cell-wall-binding modules, the catalytic domains of which define a new GH family. The properties of some representative members of this family are described as well as X-ray structures of the independent catalytic and SH3-like domains of the Kionochaeta sp., Thermothielavioides terrestris and Penicillium virgatum enzymes. This work confirms the power of the module-walking approach, extends the library of known GH families and adds a new noncatalytic module to the muramidase arsenal.

Insights on biological phosphorus removal with partial nitrification in single sludge system via sidestream free ammonia and free nitrous acid dosing.

The sidestream sludge treatment by free ammonium (FA)/free nitrous acid (FNA) dosing was frequently demonstrated to maintain the nitrite pathway for the partial nitrification (PN) process. Nevertheless, the inhibitory effect of FA and FNA would severely influence polyphosphate accumulating organisms (PAOs), destroying the microbe-based phosphorus (P) removal. Therefore, a strategic evaluation was proposed to successfully achieve biological P removal with a partial nitrification process in a single sludge system by sidestream FA and FNA dosing. Through the long-term operation of 500 days, excellent phosphorus, ammonium and total nitrogen removal performance were achieved at 97.5 ± 2.6 %, 99.1 ± 1.0 % and 75.5 ± 0.4 %, respectively. Stable partial nitrification with a nitrite accumulation ratio (NAR) of 94.1 ± 3.4 was attained. The batch tests also reported the robust aerobic phosphorus uptake based on FA and FNA adapted sludge after exposure of FA and FNA, respectively, suggesting the FA and FNA treatment strategy could potentially offer the opportunity for the selection of PAOs, which synchronously have the tolerance to FA and FNA. Microbial community analysis suggested that Accumulibacter, Tetrasphaera, and Comamonadaceae collectively contributed to the phosphorus removal in this system. Summarily, the proposed work presents a novel and feasible strategy to integrate enhanced biological phosphorus removal (EBPR) and short-cut nitrogen cycling and bring the combined mainstream phosphorus removal and partial nitrification process closer to practical application.

Efficient and robust chiral discrimination by invariant-based inverse engineering.

We propose an accurate and convenient method to achieve 100% discrimination of chiral molecules with Lewis-Riesenfeld invariance. By reversely designing the pulse scheme of handed resolution, we obtain the parameters of the three-level Hamiltonians to achieve this goal. For the same initial state, we can completely transfer its population to one energy level for left-handed molecules, while transferring it to another energy level for right-handed molecules. Moreover, this method can be further optimized when errors exist, and it shows that the optimal method is more robust against these errors than the counterdiabatic and original invariant-based shortcut schemes. This provides an effective, accurate, and robust method to distinguish the handedness of molecules.