Effect of Different Edible Trichosanthes Germplasm on Its Seed Oil to Enhance Antioxidant and Anti-Aging Activity in Caenorhabditis elegans.

The seeds of various Trichosanthes L. plants have been frequently used as snacks instead of for traditional medicinal purposes in China. However, there is still a need to identify the species based on seeds from Trichosanthes germplasm for the potential biological activities of their seed oil. In this study, 18 edible Trichosanthes germplasm from three species were identified and distinguished at a species level using a combination of seed morphological and microscopic characteristics and nrDNA-ITS sequences. Seed oil from the edible Trichosanthes germplasm significantly enhanced oxidative stress tolerance, extended lifespan, delayed aging, and improved healthspan in Caenorhabditis elegans. The antioxidant activity of the seed oil exhibits a significant positive correlation with its total unsaturated fatty acid content among the 18 edible Trichosanthes germplasm, suggesting a genetic basis for this trait. The biological activities of seed oil varied among species, with T. kirilowii Maxim. and T. rosthornii Harms showing stronger effects than T. laceribractea Hayata.

Targeting IRG1 reverses the immunosuppressive function of tumor-associated macrophages and enhances cancer immunotherapy.

Immune-responsive gene 1 (IRG1) encodes aconitate decarboxylase (ACOD1) that catalyzes the production of itaconic acids (ITAs). The anti-inflammatory function of IRG1/ITA has been established in multiple pathogen models, but very little is known in cancer. Here, we show that IRG1 is expressed in tumor-associated macrophages (TAMs) in both human and mouse tumors. Mechanistically, tumor cells induce Irg1 expression in macrophages by activating NF-κB pathway, and ITA produced by ACOD1 inhibits TET DNA dioxygenases to dampen the expression of inflammatory genes and the infiltration of CD8+ T cells into tumor sites. Deletion of Irg1 in mice suppresses the growth of multiple tumor types and enhances the efficacy of anti-PD-(L)1 immunotherapy. Our study provides a proof of concept that ACOD1 is a potential target for immune-oncology drugs and IRG1-deficient macrophages represent a potent cell therapy strategy for cancer treatment even in pancreatic tumors that are resistant to T cell-based immunotherapy.

[Clinical application of targeted sealing with high viscosity bone cement and secondary injection of low viscosity bone cement in vertebroplasty].

OBJECTIVE: To observe the clinical efficacy of targeted sealing with high viscosity bone cement and secondary injection of low viscosity bone cement in the treatment of OVCFs patients with the fracture lines involved vertebral body margin. METHODS: The elderly patients who underwent vertebroplasty for osteoporotic vertebral compression fractures from January 2019 to September 2021 were selected as the screening objects. Through relevant standards and further CT examination, 56 patients with fracture lines involving the anterior wall or upper and lower endplates of the vertebral body were selected for the study. There were 21 males and 35 females, aged from 67 to 89 years old with an average of (76.58±9.68) years. All 56 patients underwent secondary injection of bone cement during operation. Only a small amount of high viscosity cement was targeted to seal the edge of the vertebral body for the first time, and low viscosity cement was injected to the vertebral bodies during second bolus with well-distributed. The operation time, bone cement volume and bone cement leakage were recorded, and the pain relief was evaluated by visual analogue scale (VAS). RESULTS: All patients were followed up for more than 3 months and the surgeries were successfully complete. The operation time was (50.41±10.30) min and the bone cement volume was (3.64±1.29) ml. The preoperative VAS was (7.21±2.41) points, which decreased significantly to (2.81±0.97) points 3 days after operation(P<0.05). Among the 56 patients, 2 cases(3.57%) had bone cement leakage, 1 case leaked to the paravertebral vein, and 1 case slightly bulged to the paravertebral through the crack when plugging the vertebral crack. Both patients had no obvious clinical symptoms. CONCLUSION: In vertebroplasty surgery, targeted sealing of high viscosity bone cement and secondary injection of low viscosity bone cement can reduce intraoperative bone cement leakage and improve the safety of operation.

Different types of diabetes mellitus and risk of thyroid cancer: A meta-analysis of cohort studies.

Objective: Sex-specific thyroid cancer risk exists in patients diagnosed with diabetes mellitus (DM). However, thyroid cancer risk in different types of DM is still unclear. This meta-analysis aims to identify the real correlation between different types of DM and thyroid cancer risk in both sexes. Methods: Studies were identified by an electronic search of PubMed, EMBASE, and Cochrane Library on 16 January 2022. A random-effects model was used to estimate the relative risks (RRs). The Cochran's Q and I2 statistics were computed to detect heterogeneity between studies. Results: In comparison with non-DM counterparts, patients with DM had a 1.32-fold higher risk of thyroid cancer (95% CI, 1.22-1.44) with 1.26-fold (95% CI, 1.12-1.41) in men and 1.36-fold (95% CI, 1.22-1.52) in women, respectively. Subgroup analysis by the type of DM showed that the RR of thyroid cancer in patients with type 2 diabetes was 1.34 (95% CI, 1.17-1.53) in the study population with 1.32 (95% CI, 1.12-1.54) in men and 1.37 (95% CI, 1.12-1.68) in women, respectively; the RR of thyroid cancer was 1.30 (95% CI, 1.17-1.43) in patients with gestational diabetes; the risk of thyroid cancer in patients with type 1 diabetes was 1.51-fold in women but not in men. Although there were some heterogeneities, it did not affect the above results of this study. Conclusion: This study indicates that, compared with non-DM individuals, patients with any type of DM have an elevated thyroid cancer risk. This positive correlation between type 2 diabetes and thyroid cancer risk exists in both men and women. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/, CRD42022304028.

Retraction notice to "Ginsenoside Rg3 inhibits growth and epithelial-mesenchymal transition of human oral squamous carcinoma cells by down-regulating miR-221" [Eur. J. Pharmacol. 853 (2019) 353-363].

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. Given the comments regarding this article https://pubpeer.com/publications/917A4D8593F06C8E5ADC7AA0A30136, particularly regarding the background of the Western Blots from Figure 2B, the journal requested the authors to provide the raw data. However, the authors were not able to fulfil this request and therefore the Editor-in-Chief decided to retract the article.

Prognostic Factors for Excellent Response to Initial Therapy in Patients With Papillary Thyroid Cancer From a Prospective Multicenter Study.

Prognostic factors for excellent response (ER) to initial therapy in patients with papillary thyroid cancer (PTC) have not been determined. In this study, we investigated the response to initial therapy in PTC patients and independent prognostic factors for ER in a prospective multicenter study in China. A total of 506 PTC patients from nine centers in China were enrolled in this study, all of whom underwent total or near total thyroidectomy with lymph node dissection and subsequent radioiodine therapy. Univariate and multivariable logistic regression analyses were carried out to determine the independent prognostic factors for ER. The optimal cutoff value of the number of metastatic lymph nodes for predicting ER was determined by the receiver operating characteristic curve. A total of 139 patients (27.5%) achieved ER after initial therapy. Extrathyroidal extension, the number of metastatic lymph nodes, and preablative-stimulated thyroglobulin (Ps-Tg) were independent risk factors for ER for the entire population. In a subgroup analysis, extrathyroidal extension and Ps-Tg were independent risk factors for ER in pathological N1a patients, while the number of metastatic lymph nodes and Ps-Tg were independent risk factors for ER in pathological N1b patients. The appropriate cutoff values of the number of metastatic lymph nodes in predicting ER were 5 and 13 for the entire population and pathological N1b PTC patients, respectively. PTC patients with more metastatic lymph nodes were more likely to fail to achieve ER. Extrathyroidal extension, the number of metastatic lymph nodes, and Ps-Tg were important prognostic factors for ER after initial therapy in PTC patients.

Sec-O-Glucosylhamaudol Inhibits RANKL-Induced Osteoclastogenesis by Repressing 5-LO and AKT/GSK3ß Signaling.

Sec-O-glucosylhamaudol (SOG), an active flavonoid compound derived from the root of Saposhnikovia divaricata (Turcz. ex Ledeb.) Schischk., exhibits analgesic, anti-inflammatory, and high 5-lipoxygenase (5-LO) inhibitory effects. However, its effect on osteoclastogenesis was unclear. We demonstrated that SOG markedly attenuated RANKL-induced osteoclast formation, F-actin ring formation, and mineral resorption by reducing the induction of key transcription factors NFATc1, c-Fos, and their target genes such as TRAP, CTSK, and DC-STAMP during osteoclastogenesis. Western blotting showed that SOG significantly inhibited the phosphorylation of AKT and GSK3ß at the middle-late stage of osteoclastogenesis without altering calcineurin catalytic subunit protein phosphatase-2ß-Aα expression. Moreover, GSK3ß inhibitor SB415286 partially reversed SOG-induced inhibition of osteoclastogenesis, suggesting that SOG inhibits RANKL-induced osteoclastogenesis by activating GSK3ß, at least in part. 5-LO gene silencing by small interfering RNA in mouse bone marrow macrophages markedly reduced RANKL-induced osteoclastogenesis by inhibiting NFATc1. However, it did not affect the phosphorylation of AKT or GSK3ß, indicating that SOG exerts its inhibitory effects on osteoclastogenesis by suppressing both the independent 5-LO pathway and AKT-mediated GSK3ß inactivation. In support of this, SOG significantly improved bone destruction in a lipopolysaccharide-induced mouse model of bone loss. Taken together, these results suggest a potential therapeutic effect for SOG on osteoclast-related bone lysis disease.

Outcomes from the Use of Perioperative Extracorporeal Membrane Oxygenation in Patients Undergoing Thoracic Surgery: An 8-Year Single-Center Experience.

BACKGROUND Extracorporeal membrane oxygenation (ECMO) plays an important role in thoracic surgery. This retrospective study from a single center aimed to evaluate patient outcomes from the use of perioperative ECMO in 22 patients undergoing thoracic surgery during an 8-year period. MATERIAL AND METHODS Data were collected retrospectively from 22 patients who received ECMO (veno-arterial and veno-venous ECMO) as perioperative treatment during general thoracic surgery from January 2012 to October 2020. Patients required ECMO due to perioperative cardiopulmonary resuscitation (CPR) (2 cases), perioperative pulmonary embolism (PE) (2 cases), lung transplant (4 cases), undergoing complicated thoracic surgery (5 cases), postoperative acute respiratory distress syndrome (ARDS) (6 cases), and thoracic trauma (3 cases). RESULTS Veno-arterial ECMO was used for circulatory support in 13 cases and veno-venous ECMO was used for respiratory support in 9 cases. The average ECMO support time was 71.6±42.4 h. Twenty patients (90.9%) were successfully decannulated and 17 (77.2%) survived to discharge. Complications included severe hemorrhage (3/22 patients, 13.6%), sepsis (3/22, 13.6%), and destruction of blood cells (1/22, 4.5%). There were no significant differences in survival rates between patients receiving pre- or postoperative ECMO (P=0.135) or between veno-venous ECMO (V-V ECMO) and veno-arterial ECMO (V-A ECMO) (P=0.550). CONCLUSIONS The findings from this small retrospective study from a single center showed that perioperative ECMO improved cardiac and respiratory function in patients undergoing thoracic surgery. Optimal results require surgeons to have an understanding of the indications and ability to control the complications of ECMO.

An 8-arylselenium BODIPY fluorescent probe for rapid and sensitive discrimination of biothiols in living cells.

By introducing 8-arylselenium as the active group, a BODIPY fluorescent probe ASeBD was constructed for rapid and sensitive detection and dual-channel discrimination of GSH and Cys/Hcy in solution and in living cells, and its mechanism was demonstrated.

Differentiating Glioblastoma from Primary Central Nervous System Lymphoma: The Value of Shaping and Nonenhancing Peritumoral Hyperintense Gyral Lesion on FLAIR Imaging.

BACKGROUND: This study describes a distinct magnetic resonance imaging (MRI) feature, placing emphasis on fluid-attenuation inversion recovery (FLAIR) and contrast-enhanced T1-weighted (T1C) images for the preoperative differentiation of glioblastoma (GBM) from primary central nervous system lymphoma (PCNSL). METHODS: The preoperative MRI findings of 116 pathologically confirmed glioblastoma (n = 72) and PCNSL (n = 44) were retrospectively reviewed. Two neuroimaging specialists analyzed the MRIs, and image analysis was focused on the presence or absence of a shaping and nonenhancing peritumoral hyperintense gyral lesion on FLAIR imaging (SNEPGF, i.e., hyperintense lesion in a shaping and nonenhancing peritumoral gyral area on FLAIR imaging). The gyral area adjacent to and within 3 cm of the enhanced tumor was defined as the peritumoral gyrus region. The FLAIR hyperintensity lesion were termed as the signal intensity ratio ≥30% compared with contralateral normal gray matter. Then, the differential diagnostic efficacy of SNEFPG sign for GBM and PCNSL was analyzed. RESULTS: The SNEPGF sign was found in 33 GBM cases (33 of 72, 45.8%), and the FLAIR signal intensity and apparent diffusion coefficient value of these area were lower than the peritumoral edema area (P < 0.0001). In 44 PCNSL cases, no SNEPGF sign was found. A slightly higher FLAIR signal intensity was seen in 9 PCNSLs, but uniform and marked enhancement was seen in these areas. The sensitivity, specificity, positive predictive value, and negative predictive value of the differential diagnosis of GBM and PCNSL with SNEPGF sign were 45.8%, 100%, 100%, and 53.0%, respectively. CONCLUSIONS: The SNEPGF sign is effective in identifying GBM from PCNSL, especially with high specificity.

A Case Report of Sedation Strategy for a Patient With Coronavirus Disease 2019 Supported by Extracorporeal Membrane Oxygenation After Cesarean Section.

Pneumonia caused by coronavirus disease 2019 (COVID-19) is a highly contagious disease. Unfortunately, research on extracorporeal membrane oxygenation (ECMO) assisted treatments for patients with COVID-19 infection is limited. In this case study, a patient who was in late pregnancy (35+2 weeks of pregnancy) and suffering from severe COVID-19 was extremely irritable during ECMO-assisted treatment after she underwent a cesarean section. Her Richmond Agitation Sedation Scale (RASS) score reached +3. Nevertheless, the patient successfully was treated with a continuous single/combined application of propofol, midazolam, dexmedetomidine, hibernation mixture, and other drugs for several days (maintaining RASS -2 to -4) and provided with anti-infection, mechanical ventilation, nutritional support, fluid balance under hemodynamic monitoring, liver support, and other organ function support treatments. ECMO-assisted sedation strategy for patients was introduced and discussed in this case to provide a certain reference for the clinical diagnosis and treatment of such patients.

Extracorporeal Membrane Oxygenation-Combined Surgery for Hemoptysis Caused by a Mediastinal Hemangioma.

The diagnosis and treatment of massive hemoptysis remain challenging. We report a 28-year-old woman with refractory massive hemoptysis caused by a mediastinal hemangioma. Despite multiple bronchial artery embolizations and fiberoptic bronchoscopy treatments, effective control of the bleeding and clearing of the airway was not possible. Finally, with the support of venovenous extracorporeal membrane oxygenation, mediastinal hemangioma resection and right upper lobe sleeve resection were simultaneously performed. During the operation, many blood clots in the airway were removed. The airway bleeding was effectively controlled, and the patient recovered.

Agrimophol suppresses RANKL-mediated osteoclastogenesis through Blimp1-Bcl6 axis and prevents inflammatory bone loss in mice.

Excessive activity of osteoclasts causes many bone-related diseases, such as rheumatoid arthritis and osteoporosis. Agrimophol (AGR), a phenolic compound, originated from Agrimonia pilosa Ledeb. In prior studies, AGR is reported to possess schistosomicidal and mycobactericidal activities. However, no reports covered its anti-osteoclastogenesis characteristic. In this study, we found that AGR inhibited RANKL-induced osteoclastogenesis, bone-resorption, F-actin ring formation, and the mRNA expression of osteoclast-associated genes such as CTSK, TRAP, MMP-9, and ATP6v0d2 in vitro. In addition, AGR suppressed RANKL-induced expression of c-Fos and NFATc1. However, AGR treatment did not affect NF-κB activation and MAPKs phosphorylation in RANKL-stimulated BMMs, which implicated that AGR might not influence the initial expression of NFATc1 mediated by NF-κB and MAPKs signaling. Our results further indicated that AGR did not alter phosphorylation levels of GSK3ß and the expression of calcineurin, which implicated that AGR treatment might not interfere with phosphorylation and de-phosphorylation of NFATc1 mediated by GSK3ß and calcineurin, respectively. B-lymphocyte-induced maturation protein-1 (Blimp1), which was regarded as a transcriptional repressor of negative regulators of osteoclastogenesis, was markedly attenuated in the presence of AGR, leading to the enhanced expression of B-cell lymphoma 6 (Bcl-6). Meanwhile, Blimp1 knockdown in BMMs by siRNA strongly enhanced the expression of Bcl6 and reduced NFATc1 induction by RANKL. These findings suggested that AGR inhibited RANKL-induced osteoclast differentiation through Blimp1-Bcl-6 signaling mediated modulation of NFATc1 and its target genes. Consistent with these in vitro results, AGR exhibited a protective influence in an in vivo mouse model of LPS-induced bone loss by suppressing excessive osteoclast activity and attenuating LPS-induced bone destruction. Hence, these results identified that AGR could be considered as a potential therapeutic agent against bone lysis disease.

Tetrahydropyrimidines, ZL-5015 Alleviated Lipopolysaccharide (LPS)-Induced Acute Pneumonia in Rats by Activating the NRF-2/HO-1 Pathway.

BACKGROUND Acute pneumonia is a severe inflammatory disease of the respiratory system. Drugs used to treat acute pneumonia often have strong side effects. Recent studies have shown that tetrahydropyrimidines, ZL-5015 has anti-inflammatory and antitumor effects. However, whether ZL-5015 can relieve symptoms of acute pneumonia is unclear. MATERIAL AND METHODS In this study, we used lipo-polysaccharide (LPS) to stimulate SD rats to simulate conditions of acute pneumonia. Diverse doses of ZL-5015 were used for treatment of these rats. After the rates were sacrificed, serum, lung tissue, and bronchoalveolar lavage fluid were collected for the next study. Hematoxylin-eosin (H&E) staining then was used to detect pathologic changes in lung tissues. Enzyme-linked immunosorbent assay was performed to assess levels of inflammatory factors in serum. Commercial kits were used to assess levels of reactive oxygen species (ROS) in bronchoalveolar lavage fluid. RESULTS Treatment of ZL-5015 relieved stenosis of the alveolar space and pulmonary edema. Furthermore, levels of inflammatory factors (TNF-alpha, IL-1ß and IL-18) in the lung tissues and serum were downregulated after treatment with ZL-5015. Production of ROS also was suppressed after application of ZL-5015. Moreover, inhibition of expression of NRF-2 and HO-1 was relieved after treatment with ZL-5015. The therapeutic effect of ZL-5015 showed a dose-response relationship. CONCLUSIONS ZL-5015 alleviated LPS-induced inflammatory injury and oxidative damage by activating the NRF-2/HO-1 pathway.

Highly efficient replacement of traditional intumescent flame retardants in polypropylene by manganese ions doped melamine phytate nanosheets.

The intumescent flame retardant (IFR) with ammonium polyphosphate (APP) as the main component has many defects in practical applications, more than that, APP can be traced to non-renewable phosphate rock resources. For the foregoing reasons, the melamine phytate supramolecular nanosheet flame retardant incorporating manganese ion (PAMA-Mn) was successfully prepared with a facile and environmental friendly hydrothermal procedure based on renewable bio-based material phytic acid (PA). The flame retardant polypropylene composite (PPI) with 13.5 wt% APP and 4.5 wt% pentaerythritol (PER) failed to the UL-94 test, and its limiting oxygen index (LOI) value was only 26.5%. After 33 wt% of APP was replaced by PAMA-Mn, the PPMn33 incorporating only 18 wt% flame retardant additives passed the UL-94 V-0 rating, and its LOI value was increased to 31.9%. Compared with PP, pHRR and pSPR values of PPMn33 were reduced by 56% and 23%, respectively. The fire retardant mechanism of PPMn33 was thoroughly discussed via a variety of characterization methods. It was found that the peak of the Gram-Schmidt curve of PPMn33 was drastically reduced by 49% relative to that of PPI, indicating a remarkably decrease of combustible volatile products owing to the incorporation of PAMA-Mn, thereby rapidly reducing the fire hazard risk.

The Zscan4-Tet2 Transcription Nexus Regulates Metabolic Rewiring and Enhances Proteostasis to Promote Reprogramming.

Evolutionarily conserved SCAN (named after SRE-ZBP, CTfin51, AW-1, and Number 18 cDNA)-domain-containing zinc finger transcription factors (ZSCAN) have been found in both mouse and human genomes. Zscan4 is transiently expressed during zygotic genome activation (ZGA) in preimplantation embryos and induced pluripotent stem cell (iPSC) reprogramming. However, little is known about the mechanism of Zscan4 underlying these processes of cell fate control. Here, we show that Zscan4f, a representative of ZSCAN proteins, is able to recruit Tet2 through its SCAN domain. The Zscan4f-Tet2 interaction promotes DNA demethylation and regulates the expression of target genes, particularly those encoding glycolytic enzymes and proteasome subunits. Zscan4f regulates metabolic rewiring, enhances proteasome function, and ultimately promotes iPSC generation. These results identify Zscan4f as an important partner of Tet2 in regulating target genes and promoting iPSC generation and suggest a possible and common mechanism shared by SCAN family transcription factors to recruit ten-eleven translocation (TET) DNA dioxygenases to regulate diverse cellular processes, including reprogramming.

Vascular Complications of Lower Limb Ischemia in Patients with Femoral Venoarterial Extracorporeal Membrane Oxygenation.

BACKGROUND: Lower limb ischemia in patients with extracorporeal membrane oxygenation (ECMO) via femoral artery catheterization negatively affects patient mortality and survivors' quality of life [Gulkarov 2020]. In this study, ECMO was established via femoral artery catheterization. This study aimed to identify the risk factors of lower limb ischemia to provide sufficient evidence for its prevention. METHODS: All patients with venoarterial (VA) ECMO via femoral artery catheterization in Zhongshan People's Hospital from January 2008 to November 2019 retrospectively were analyzed. Patients' general information and ECMO-related information were obtained, and the main outcome variables were survival and discharge and intubation-related adverse events (limb ischemia and incision bleeding). Logistic regression analysis was used to determine the independent risk factors of limb ischemia in patients with VA ECMO. RESULTS: A total of 179 (98 [54.7%] men and 81 [45.3%] women) eligible patients were included in this study. Moreover, a total of 90 patients (48.9%) had low cardiac output, 41 (22.3%) had acute myocardial infarction, and 33 (17.9%) had fulminant myocarditis. Eighty-six (48.04%) patients survived to hospital discharge, 36 (20.11%) had limb ischemia, and 42 (23.46%) had incision bleeding. Furthermore, the ECMO-assisted time was 114.23 ± 67.88 hours. There was no significant difference in age, sex, and Sequential Organ Failure Assessment score between the limb ischemia group and the non-limb ischemia group. Multivariate logistic regression analysis showed that peripheral artery disease (odds ratio, 27.12; 95% confidence interval, 5.614-130.96) was an independent risk factor of limb ischemia in patients with ECMO. CONCLUSION: Limb ischemia is a common complication in patients with VA ECMO, and peripheral artery disease is an independent risk factor of limb ischemia in patients with VA ECMO via femoral artery catheterization.

Application of Extracorporeal Membrane Oxygenation in Patients with Scrub Typhus Complicated with Acute Respiratory Distress Syndrome.

A 68-year-old woman was diagnosed with scrub typhus and acute pneumonia. Acute respiratory distress syndrome (ARDS) occurred on day 4 after admission and was treated with extracorporeal membrane oxygenation (ECMO). After 7 days of ECMO assistance, her respiratory condition gradually improved, and ECMO was removed. On day 20 after admission, she was discharged without any sequelae. The results suggest that ECMO should be considered as early as possible for patients with ARDS caused by scrub typhus.

Precise preparation of WO3@SnO2 core shell nanosheets for efficient NH3 gas sensing.

Development of high-performance ammonia (NH3) sensor is imperative for monitoring NH3 in the living environment. In this work, to obtain a high performance NH3 gas sensor, structurally well-defined WO3@SnO2 core shell nanosheets with a controllable thickness of SnO2 shell layer have been employed as sensing materials. The prepared core shell nanosheets were used to obtain a miniaturized gas sensor based on micro-electro-mechanical system (MEMS). By tuning the thickness of SnO2 layer via atomic layer deposition, a series of WO3@SnO2 core-shell nanosheets with tunable sensing properties were realized. Particularly, the sensor base on the fabricated WO3@SnO2 nanosheets with 20-nm SnO2 shell layer demonstrated superior gas sensing performance with the highest response (1.55) and selectivity toward 15 ppm NH3 at 200 °C. This remarkable enhancement of NH3 sensing ability could be ascribed to the formation of unique WO3-SnO2 core-shell heterojunction structure. The detailed mechanism was elucidated by the heterojunction-depletion model with the help of specific band alignment.

Promoting bidirectional extracellular electron transfer of Shewanella oneidensis MR-1 for hexavalent chromium reduction via elevating intracellular cAMP level.

The bioreduction capacity of Cr(VI) by Shewanella is mainly governed by its bidirectional extracellular electron transfer (EET). However, the low bidirectional EET efficiency restricts its wider applications in remediation of the environments contaminated by Cr(VI). Cyclic adenosine 3',5'-monophosphate (cAMP) commonly exists in Shewanella strains and cAMP-cyclic adenosine 3',5'-monophosphate receptor protein (CRP) system regulates multiple bidirectional EET-related pathways. This inspires us to strengthen the bidirectional EET through elevating the intracellular cAMP level in Shewanella strains. In this study, an exogenous gene encoding adenylate cyclase from the soil bacterium Beggiatoa sp. PS is functionally expressed in Shewanella oneidensis MR-1 (the strain MR-1/pbPAC) and a MR-1 mutant lacking all endogenous adenylate cyclase encoding genes (the strain Δca/pbPAC). The engineered strains exhibit the enhanced bidirectional EET capacities in microbial electrochemical systems compared with their counterparts. Meanwhile, a three times more rapid reduction rate of Cr(VI) is achieved by the strain MR-1/pbPAC than the control in batch experiments. Furthermore, a higher Cr(VI) reduction efficiency is also achieved by the strain MR-1/pbPAC in the Cr(VI)-reducing biocathode experiments. Such a bidirectional enhancement is attributed to the improved production of cAMP-CRP complex, which upregulates the expression levels of the genes encoding the c-type cytochromes and flavins synthetic pathways. Specially, this strategy could be used as a broad-spectrum approach for the other Shewanella strains. Our results demonstrate that elevating the intracellular cAMP levels could be an efficient strategy to enhance the bidirectional EET of Shewanella strains and improve their pollutant transformation capacity.