The "4 + 1" strategy fabrication of iron single-atom catalysts with selective high-valent iron-oxo species generation.

Single-atom catalysts (SACs) with atomic dispersion active sites have exhibited huge potentials in peroxymonosulfate (PMS)-based Fenton-like chemistry in water purification. However, four-N coordination metal (MN4) moieties often suffer from such problems as low selectivity and narrow workable pH. How to construct SACs in a controllable strategy with optimized electronic structures is of great challenge. Herein, an innovative strategy (i.e., the "4 + 1" fabrication) was devised to precisely modulate the first-shell coordinated microenvironment of FeN4 SAC using an additional N (SA-FeN5). This leads to almost 100% selective formation of high-valent iron-oxo [Fe(IV)═O] (steady-state concentration: 2.00 × 10-8 M) in the SA-FeN5/PMS system. In-depth theoretical calculations unveil that FeN5 configuration optimizes the electron distribution of monatomic Fe sites, which thus fosters PMS adsorption and reduces the energy barrier for Fe(IV)═O generation. SA-FeN5 was then attached to polyvinylidene difluoride membrane for a continuous flow device, showing long-term abatement of the microcontaminant. This work furnishes a general strategy for effective PMS activation and selective high-valent metal-oxo species generation by high N-coordination number regulation in SACs, which would provide guidance in the rational design of superior environmental catalysts for water purification.

MiR-340 suppresses the metastasis by targeting EphA3 in cervical cancer.

MicroRNAs (miRNAs) play key roles in cervical cancer metastasis progression. Accumulated evidences have revealed that miRNAs are related to the pathophysiological process. However, the role of miR-340 in cervical cancer and how it works is still not fully interpreted. Using qRT-PCR to examine the expression of miR-340 in cervical cancer tissues. Transwell migration and invasion experiments were used to detect the role of miR-340 in migration and invasion. Luciferase reporter assay, qRT-PCR, and Western blot were used to detect the relationship between miR-340 and EphA3. Using Transwell migration and invasion experiments to investigate the role of EphA3 on migration and invasion. Restoration expriments were also performed. Western blot was used to assay the influence of miR-340 and EphA3 on EMT. We found that miR-340 was downregulated in cervical cancer tissues compared with the normal tissues. Transwell migration and invasion experiments indicated that overexpression of miR-340 frequently inhibited the migration and invasion of cervical cancer cells. EphA3 is a target of miR-340, and ectopic expression of EphA3 can promote the migration and invasion of cervical cancer cells, whereas restoration of EphA3 in miR-340-overexpressing cervical cancer cells reversed the suppressive effects of miR-340. What's more, the process of migration and invasion which regulated by miR-340/EphA3 was depended on adjusting the EMT way. These findings indicate that miR-340 may act as an anti-tumor factor during the process of tumor metastasis through targeting EphA3, suggesting that miR-340 might be a potential new diagnostic and therapeutic molecule for the treatment of cervical cancer.

Selective electrophilic attack towards organic micropollutants with superior Fenton-like activity by biochar-supported cobalt single-atom catalyst.

The global shortage of freshwater and inadequate supply of clean water have necessitated the implementation of robust technologies for wastewater purification, and Fenton-like chemistry is a highly-promising approach. However, realizing the rapid Fenton-like chemistry for high-efficiency degradation of organic micropollutants (OMs) remains challenging. Herein, one novel system was constructed by a Co single-atom catalyst activating peroxymonosulfate (PMS), and the optimal system (SA-Co-NBC-0.2/PMS) achieved unprecedented catalytic performance towards a model OM [Iohexol (IOH)], i.e., almost 100% decay ratio in only 10 min (the observed rate constant: 0.444 min-1) with high electrophilic species 1O2 (singlet oxygen) generation. Theoretical calculations unveiled that Co-N4 sites preferred to adsorb the terminal-O of PMS (more negative adsorption energy than other O sites: -32.67 kcal/mol), promoting the oxidation of PMS to generate 1O2. Iodine (I)23 (0.1097), I24 (0.1154) and I25 (0.0898) on IOH with higher f- electrophilic values were thus identified as the main attack sites. Furthermore, 16S ribosomal RNA high-throughput sequencing and quantitative structure-activity relationship analysis illustrated the environmentally-benign property of the SA-Co-NBC-0.2 and the tapering ecological risk during IOH degradation process. Significantly, this work comprehensively checked the competence of the SA-Co-NBC-0.2/PMS system for organics abatement in practical wastewater.

A general way to realize the bi-directional promotion effects on the photocatalytic removal of heavy metals and organic pollutants in real water by a novel S-scheme heterojunction: Experimental investigations, QSAR and DFT calculations.

Heavy metals (HMs) often coexist with organic pollutants (OPs) in real surface water. Is it possible to find a general way that the removal of one from these two pollutants will promote the elimination of another pollutant? Herein, the bi-directional promotion effects (BPEs) on synchronous removal of Cr(VI) (i.e., hexavalent chromium) and OPs were achieved by a SnNb2O6/CuInS2 S-scheme heterojunction. Specifically, the apparent rate constants are 0.161 min-1 [(Cr(VI)] and 0.019 min-1 [Tetracycline hydrochloride (TCH)] in coexisting Cr(VI)/TCH system (which are 3.74 and 1.58 times, respectively, compared to the mono-pollutant system), indicating OPs indeed can act as hole scavengers (electron donors) to consume plenty of photoinduced holes and enable more photoexcited electrons to attend to Cr(VI) photoreduction. More significantly, OPs (i.e., TCH, atrazine and 4-chlorophenol) with different molecular structures possess different adiabatic ionization potentials (AIPs), in an inversely linear relationship with BPEs, i.e., the lower AIP value is, the higher electron-donating ability is, the better BPEs present. Finally, TCH and its degradation intermediates toxicity was forecasted via quantitative structure-activity relationship, demonstrating the toxicity decrease of TCH during the photocatalytic process. This work provides a general strategy for simultaneous removal of contaminants, contributing to wastewater purification.

The expression of Nanog protein and fibroblast growth factor-inducible molecule 14 in patients with non-small cell lung cancer and their relationship with pathological characteristics and prognosis.

BACKGROUND: This study aimed to explore the expression of Nanog and fibroblast growth factor-inducible molecule 14 (Fn14) in patients with non-small cell lung cancer (NSCLC), and to explore their relationship with pathological characteristics and prognosis. METHODS: The clinical data of 89 patients with NSCLC admitted to this hospital from March 2015 to January 2019 were analyzed. The expression of Nanog and Fn14 in NSCLC tissues and normal tissues (5 cm around the tumor tissue) were analyzed by immunohistochemical staining. The relationship between Nanog and Fn14 expression and the patients' pathological parameters was analyzed. Receiver operating characteristic curve (ROC) and Kaplan-Meier survival curves were drawn to analyze the influence of Nanog and Fn14 expression on prognosis, and logistic regression analysis was used to examine the related factors affecting the 2-year prognostic mortality of patients. RESULTS: The positive rates of Nanog and Fn14 in the observation group were significantly higher than those in the control group (P<0.05). The positive expression rates of Nanog and Fn14 were higher in patients with moderate/high differentiation, TNM stage III-IV, and lymph node metastasis (P<0.05). Among 89 patients with NSCLC, 25 patients died within 2 years of follow-up, with a survival rate of 71.91%. The mortality of patients with positive expression of Nanog and Fn14 was significantly higher than that of patients with negative expression (P<0.05). The median survival times of patients with negative and positive Nanog expression were (20.60±2.71) months and (18.03±2.11) months, respectively. The median survival times of patients with negative and positive Fn14 expression were (19.55±2.60) months and (15.65±2.14) months, respectively. The Kaplan-Meier survival curve showed that patients with both negative expression of Nanog and Fn14 had a longer survival time (P<0.05). Poor differentiation, TNM stage III-IV, lymph node metastasis, positive expression of Nanog, and positive expression of Fn14 were identified as risk factors affecting the prognostic mortality of patients with NSCLC (P<0.05). CONCLUSIONS: Nanog and Fnl4 are closely related to the occurrence, development, and prognosis of NSCLC. Detection of their expression levels can provide reliable information for the early diagnosis of patients with NSCLC.

Caspase-8 preferentially senses the apoptosis-inducing action of NG-18, a Gambogic acid derivative, in human leukemia HL-60 cells.

Gambogic acid (GA) is the major active ingredient of gamboge secreted from a Chinese traditional medicine Garcinia hanburryi possessing potent anti-tumor activity. N-(2-ethoxyethyl)gambogamide (NG-18), a derivative of GA, also efficiently inhibits proliferation of cultured human tumor cells. The inhibition effect of NG-18 is associated with its ability to induce apoptosis. In the present study, NG-18 markedly induced leukemia HL-60 cells apoptosis, and the extrinsic and intrinsic apoptosis pathways were activated almost at the same time. NG-18-induced tumor cell apoptosis was associated with up-regulation of pro-apoptotic Bcl-2 family member Bax, and downregulation of anti-apoptotic protein Bcl-2. The NG-18-induced apoptosis was blocked completely by a pan-caspase inhibitor Z-VAD-FMK, indicating that caspases were functionally and actively involved in this process. The specific inhibition of caspase-8 activity using Z-IETD-FMK significantly blocked NG-18-induced apoptosis. In contrast, inhibition of other initiator caspases, caspase-2 or -9, using Z-VDVAD-FMK or Z-LEHD-FMK respectively had no effect on NG-18-induced apoptosis. Altogether, our data demonstrated that NG-18-induced apoptosis was dependent on caspases and caspase-8 acted as a key executor in the event.

Three G.C base pairs required for the efficient aminoacylation of tRNATrp by tryptophanyl-tRNA synthetase from Bacillus subtilis.

Acceptor stem is an essential region in the recognition of tRNAs by their cognate aminoacyl-tRNA synthetase. In this study, a library containing 20 nt random region and tryptophanyl-tRNA synthetase (TrpRS) from Bacillus subtilis were used for in vitro selection to find a new structural feature in the tRNA(Trp) acceptor stem sequence that is required for B. subtilis TrpRS recognition. After three rounds of selection, the TrpRS binding RNAs dominate the RNA pool. The aptamers share a common structure of three G.C base pairs, which was also found in the acceptor stem of wild-type B. subtilis tRNA(Trp). A series of tRNA(Trp) variants was prepared by in vitro transcription, and their efficiencies of tryptophanylation (k(cat)/K(M)) were measured with the aid of TrpRS from B. subtilis. The mutants that possess the three G.C base pairs and G73 discriminator base exhibit almost the same aminoacylation efficiencies as B. subtilis tRNA(Trp), while the G73 discriminator base itself cannot confer efficient aminoacylation to the tRNA(Trp) molecule. Thus, these three base pairs (G2.C71, G3.C70, and G4.C69) in the B. subtilis tRNA(Trp) acceptor stem were established to be new identity elements, and their importance was between the previously characterized major element G73 and minor elements A1/U72 and G5/C68. The minimum set of identity elements that is required to confer efficient aminoacylation by B. subtilis TrpRS included G73, G2.C71, G3.C70, and G4.C69.