Scalable Synthesis of Ultrathin Polyimide Covalent Organic Framework Nanosheets for High-Performance Lithium-Sulfur Batteries.

Development of new porous materials as hosts to suppress the dissolution and shuttle of lithium polysulfides is beneficial for constructing highly efficient lithium-sulfur batteries (LSBs). Although 2D covalent organic frameworks (COFs) as host materials exhibit promising potential for LSBs, their performance is still not satisfactory. Herein, we develop polyimide COFs (PI-COF) with a well-defined lamellar structure, which can be exfoliated into ultrathin (∼1.2 nm) 2D polyimide nanosheets (PI-CONs) with a large size (∼6 µm) and large quantity (40 mg/batch). Explored as new sulfur host materials for LSBs, PI-COF and PI-CONs deliver high capacities (1330 and 1205 mA h g-1 at 0.1 C, respectively), excellent rate capabilities (620 and 503 mA h g-1 at 4 C, respectively), and superior cycling stability (96% capacity retention at 0.2 C for PI-CONs) by virtue of the synergy of robust conjugated porous frameworks and strong oxygen-lithium interactions, surpassing the vast majority of organic/polymeric lithium-sulfur battery cathodes ever reported. Our finding demonstrates that ultrathin 2D COF nanosheets with carbonyl groups could be promising host materials for LSBs with excellent electrochemical performance.

Selective and rapid extraction of trace amount of gold from complex liquids with silver(I)-organic frameworks.

The design of adsorbents for rapid, selective extraction of ultra-trace amounts of gold from complex liquids is desirable from both an environmental and economical point of view. However, the development of such materials remains challenging. Herein, we report the fabrication of two vinylene-linked two-dimensional silver(I)-organic frameworks prepared via Knoevenagel condensation. This material enables selective sensing of gold with a low limit of detection of 60 ppb, as well as selective uptake of ultra-trace gold from complex aqueous mixtures including distilled water with 15 competing metal ions, leaching solution of electronic waste (e-waste), wastewater, and seawater. The present adsorbent delivers a gold adsorption capacity of 954 mg g-1, excellent selectivity and reusability, and can rapidly and selectively extract ultra-trace gold from seawater down to ~20 ppb (94% removal in 10 minutes). In addition, the purity of recovered gold from e-waste reaches 23.8 Karat (99.17% pure).

[Construction and expression of hTNF-alpha fusion protein mediated by MMP1].

This paper is aimed to present a research on fusion protein of human tumor necrosis factor-alpha (hTNF-alpha), matrix metalloproteinase 1 (MMP1), and foldon sequence using the methord of gene engineering. We transformed the recombinant plasmid, which contains the DNA sequences of hTNF-alpha, MMP1, and foldon sequence, into Rosetta2, and successfully induced the fusion protein to express under given conditions by isopropyl beta-D-1-Thiogalactopyranoside (IPTG). Then we purified the expression product through a glutathione S-transferase (GST) resin and collected the interested protein. This research may lay the groundwork for scientific research and clinical application.

Acid-triggered interlayer sliding of two-dimensional copper(i)-organic frameworks: more metal sites for catalysis.

The interlay sliding of two-dimensional (2D) metal-organic and covalent-organic frameworks (MOFs and COFs) affects not only the layout features of the structures, but also the functional output of the materials. However, the control of interlay stacking is the major hurdle that needs to be overcome to construct new functional layer materials. Herein, we report the preparation of a pair of isostructural 2D copper(i) organic frameworks with an eclipsed AA stacking structure, namely JNM-3-AA, and a staggered ABC stacking topology, denoted JNM-3-ABC, by combining the chemistry of MOFs and COFs. The variation of interlayer stacking largely influences their functionality, including porosity (BET surface areas of 695.61 and 34.22 m2 g-1 for JNM-3-AA and JNM-3-ABC, respectively), chemical stability, and catalytic activities (less than 10% or ∼86% yield using JNM-3-AA or JNM-3-ABC as catalysts for click reaction, respectively). More interestingly, the structure transformation from JNM-3-ABC to JNM-3-AA is readily achieved by simple addition of trifluoroacetic acid accompanied by the extension of porosities from BET surface areas of 34.22 to 441.22 m2 g-1, resulting in in situ acceleration of the adoption rate (removal efficiency increases from ∼10 to 99.9%), which is rarely observed in 2D MOFs and COFs.

[Long non-coding RNA and cervical cancer].

Long non-coding RNAs (lncRNAs) are members of RNA that are structurally similar to mRNA. They cannot encode proteins because they do not have a conserved open reading frame. LncRNAs were once regarded as abnormalities or noises or without any biological function after gene transcription. With the further development of research, it has been found that it can participate in normal or abnormal biological processes as an important regulator. LncRNAs are closely related to the development of nervous system function, metabolic disorders and tumors. LncRNAs abnormally expressed in cervical cancer participate in the regulation of various biological processes of cervical cancer by inhibiting or promoting tumors. This article reviews the recent reports on the abnormal regulation, molecular regulation mechanism and potential clinical application of lncRNAs in cervical cancer.

Construction of the POT1 promoter report gene vector, and the effect and underlying mechanism of the POT1 promoter in regulating telomerase and telomere length.

By using human genomic DNA as a template to clone protection of telomere 1 (POT1) promoter gene segments and construct the POT1 promoter luciferase report gene vector (pGL3-Control-POT1-promoter), the association between POT1, and the regulation of telomerase and telomere length was investigated. In the present study, two recombinant luciferase report gene vectors were constructed, which included different regions of the POT1 promoter. The plasmids were transformed into DH5α and the positive clones were obtained. The two plasmids termed as pGL3-Control-POT1-promoter-1 and pGL3-Control-POT1-promoter-2, were confirmed using restriction enzyme analysis and sequencing. They were separately and transiently transfected into four types of human tumor cells (A549, H460, HepG2 and HeLa). The transcriptional activities of the POT1 promoter were verified using the dual-luciferase assay. The relative expression of POT1 and human telomerase reverse transcriptase (hTERT), and telomere length were analyzed using quantitative polymerase chain reaction in the four types of non-transfected tumor cells. Using SPSS software, correlations between POT1 promoter activity, and POT1 expression, hTERT expression and telomere length were analyzed. Two POT1 promoter fragments (POT1-promoter-1 and -2) were successfully constructed into the pGL3-Control luciferase report gene vector. POT1-promoter-1 exhibited significantly stronger transcription activity compared with POT1-promoter-2. The results of the partial correlation and linear regression analyses were similar: POT1 promoter activity was identified to be significantly and positively correlated with POT1 expression and telomere length (partial correlation coefficients, both P<0.05; linear regression, both P<0.01). However, POT1 promoter activity and hTERT expression were significantly negatively correlated (both P<0.05). The results obtained in the present study suggest that the POT1 promoter influences telomere length. Furthermore, these data indicated that POT1 promoter activity and POT1, as well as telomere length, may be a useful biomarker for tumor detection and future patient prognosis.

Intron-specific shRNA-mediated downregulation of survivin and promotion of apoptosis in HeLa cells.

Overexpression of the survivin gene contributes to tumorigenesis; it has been recognized as an important target for cancer therapy. In the present study, survivin expression was suppressed using recombinant plasmid mediated short hairpin RNAs (shRNAs) that were constructed to target exonic or intronic sequences of the survivin gene. In addition, a negative control shRNA was constructed. HeLa cells were transfected with specific shRNA constructs and the blocking efficiency of each shRNA was assessed at the mRNA and protein levels; and the five shRNA constructs with higher blocking efficiency were selected. Cell apoptosis was assessed by flow cytometry (FCM) following Annexin V-fluorescein isothiocyanate/propidium iodide double staining. Hoechst staining was used to detect the morphological diversity of the nuclei in apoptotic cells. The results demonstrated that survivin expression was effectively reduced by the transfection of shRNAs in HeLa cells. In addition, the apoptotic rates of the shRNA-treated groups were significantly increased compared with the negative control group according to the FCM results. The nuclei of HeLa cells exhibited apoptotic characteristics in the shRNA-treated groups as identified by Hoechst staining. Survivin-targeting shRNAs effectively downregulated the expression of the gene and markedly increased the apoptotic rate of HeLa cells. Data from the present study also indicated that the intron-specific shRNA demonstrate a high efficiency of inhibition of survivin expression and were able to induce cell apoptosis of HeLa cells through RNAi, potentially providing novel target sites for tumor therapy. In conclusion, the present study suggests that intron-specific blocking of survivin by RNAi may provide a tool for anticancer therapy.

Construction and characterization of a transmembrane eukaryotic expression vector based on the membrane domain structure of TNF-α.

The aim of the present study was to construct a fast-acting, eukaryotic expression vector in eukaryotic cells based on transmembrane-tumor necrosis factor­α (TM­TNF­α) structure. Two types of recombinant eukaryotic expression vectors were constructed, pcDNA3.1-TM-enterokinase-TNF­α and pcDNA3.1­TM­Factor Xa­TNF­α, according to the TNF­α transmembrane segments. Following the generation of these vectors, mouse embryonic 3T3 fibroblasts were transfected and reverse transcription­polymerase chain reaction and western blotting analyses were used to analyze mTNF­α mRNA and protein expression levels, respectively, in total cellular protein extracts and extracellular fluid. The biological activity of TNF-α in the extracellular fluid was then measured using an MTT assay. The vectors were successfully constructed, and mRNA and fusion proteins were detected in the 3T3 cells. Among the fusion proteins, the one observed in pcDNA3.1-TM-FactorXa-TNF-α-transfected 3T3 cells remained as a transmembrane protein. In addition, treatment of L929 cells with TNF­α derived extracellular fluid samples from pcDNA3.1­TM­FactorXa­TNF­α­transfected 3T3 cells was associated with a dose­dependent reduction in in cell­specific activity. The results indicate that proteins expressed using pcDNA3.1­TM­FactorXa­TNF­α vectors form transmembrane proteins. In addition, the results indicate that, only when coupled with FactorXa activity, the extracellular region of TM­TNF­α forms s­TNF­α, and the controlled expression of the fusion protein is initiated.

Antitumor effect and mechanism of action of a tumor-targeting recombinant human tumor necrosis factor-α fusion protein mediated by urokinase.

The aim of this study was to investigate the effect of the tumor­targeting recombinant human tumor necrosis factor (rhTNF)­α fusion protein mediated by urokinase on Sl80 tumor­bearing mice, as well as to explore its mechanisms of action. Furthermore, the study aimed to observe the effect of the protein on liver and kidney function. rhTNF­α fusion protein prokaryotic expression vectors were constructed using genetic engineering techniques, and were introduced into Escherichia coli. Expression of the fusion protein was induced, and it was then separated and purified in order to determine its cytotoxic activity on L929 cells. Kunming mice were randomly divided into four groups after being inoculated with S180 tumor cells. The groups were then injected with saline (control group, group S), or saline with 0.1 µg/ml fusion protein (low dose group, group L), 0.2 µg/ml fusion protein (middle dose group, group M) or 0.3 µg/ml (high dose group, group H). The mice were sacrificed after 12 days and liver [mg/kg; (liver weight/body weight) x 1,000] and kidney [mg/kg; (kidney weight/body weight) x 1,000] indices, tumor weight, the percentage reduction in mean tumor size, and the levels of alanine transaminase (ALT), albumin (ALB), creatinine (Cr) and blood urea nitrogen (BUN) in each group of mice were determined. In addition, the levels of urokinase­type plasminogen activator (uPA), the expression of bcl­2, bax and vascular endothelial growth factor (VEGF), and the percentage of apoptotic cells were measured with an enzyme­linked immunosorbent assay, streptavidin­biotin complex of immunohistochemistry and terminal deoxynucleotidyl transferase­mediated dUTP nick end labeling, respectively. The fusion protein significantly inhibited the growth of S180 tumor cells in vivo in a dose­dependent manner. With an increase in the dose of fusion protein, ALT, uPA, bcl­2 and VEGF levels decreased, and ALB levels increased. However, liver and kidney indices and bax expression were not significantly altered. Cr and BUN levels did not change significantly in the low and middle dose groups, but did increase in the high dose group. Compared with the control group, the percentage of apoptotic cells in the high­dose group was significantly higher. In conclusion, the fusion protein significantly inhibited S180 tumor growth in a mouse model, possibly by reducing the levels of uPA, bcl­2 and VEGF. There was a mildly toxic effect on the kidneys with the high dose, but a protective effect in the liver.

Matrix metalloproteinase-mediation of tumor targeting human recombinant tumor necrosis factor-α fusion protein.

The aim of the present study was to use genetic engineering in order to establish an efficient tumor necrosis factor (TNF)-α fusion protein with low toxicity, which may be used to target tumors. Four types of matrix metalloproteinase (MMP)-mediated tumor targeting human recombinant TNF-α (rhTNF-α) fusion protein vectors were constructed. These were subsequently introduced into Escherichia coli. rhTNF-α fusion protein with a glutathione S-transferase (GST)-tag was purified using GST resin affinity chromatography, and GST-tags were digested using factor Xa. The cytotoxic effects of the fusion protein on L929 cells were determined using MTT assays. At a concentration of 1 pM, the GST-tagged fusion protein exerted no cytotoxic effects on the cells, compared with the negative control cells (P=0.975>0.05). However, at a concentration of 1000 pM, the deblocking fusion protein exerted greater cytotoxic effects on L929 cells, compared with positive control cells (P<0.05). Treatment with the fusion protein also induced cell apoptosis in the nasopharyngeal cancer cell line, CNE-2Z, which secretes high levels of MMP-1. In conclusion, the results of the present study suggested that MMP-mediated rhTNF-α fusion protein induces CNE-2Z cells apoptosis. rhTNF-α exhibits high efficacy and tumor cell targeting capability, with low toxicity effects on healthy cells.

Targeting antitumor effect of rhTNF-α fusion protein mediated by matrix metalloproteinase-2.

The aim of this study was to examine the tumor therapy, targeting effects and side effects of tumor-targeting rhTNF-α fusion protein mediated by matrix metalloproteinase-2 in an animal model in order to provide experimental data for future development of drugs. The median lethal dose (LD50) was obtained from acute toxicity experiments. The A549 lung cancer xenograft model was established, and then randomly divided into the saline, standard substance, and low-, middle- and high-dose fusion protein experiment groups. Each group was administered drugs for 18 days. The length and width of the xenografts were measured every three days, after which the xenograft growth curve was drawn. The mice were sacrificed in each group following treatment and the tumor volume and weight were measured. The targeting, effectiveness and toxicity of the transformed fusion protein, and pathological changes of tumor and organ tissues were examined by hematoxylin and eosin (H&E) staining. Additionally, biochemical markers were used to detect damage of various organs after protein processing. Cell apoptosis and angiogenesis were determined using terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling (TUNEL) testing and immunohistochemistry, respectively, in different dose groups. Tumor growth was markedly retarded in the high-dose experimental and standard hTNF-α groups with antitumor rates of 85.91 and 72.25%, respectively, as compared with the control group. Furthermore, the tumor tissue showed obvious apoptosis (the apoptotic index was 78.78 and 66.65%, respectively) and pathological changes in the high-dose experimental and standard hTNF-α groups. Tumor angiogenesis in each fusion protein group was inhibited (P<0.01) and the biochemical markers of various organs were greatly reduced in the high-dose experimental group (P<0.05). This finding indicated that slight toxic effects of fusion proteins were evident for the heart, liver and kidney. The reforming fusion protein can therefore target tumor tissues and efficiently kill tumor cells, with few side effects.

[Effects of polyporus polysaccharide on activity and mRNA expression of inducible nitric oxide synthase in peritoneal macrophages of mice].

OBJECTIVE: To study the mechanisms of the antitumor and immunoregulation functions of polyporus polysaccharide (PPS). METHODS: The production of nitric oxide (NO), the activity and mRNA expression of inducible nitric oxide synthase (iNOS) in peritoneal macrophages of mice administered with different dose of PPS were observed by Griess reaction, fluorimetry assay and RT-PCR, respectively. RESULTS: PPS could elevate the iNOS activity with dose-dependence and stimulate the iNOS mRNA expression of peritoneal macrophages in mice. CONCLUSION: The regulation of PPS on the production of NO in peritoneal macrophages of mice may occur at transcriptional level of iNOS. This indicates that the mechanism of PPS's antitumor and immunoregulation functions may be related to increasing NO output of macrophages through stimulating iNOS's denovo synthesis.

[Experimental study of immunostimulatory DNA sequence in conjunction with an allergen increasing allergic rhinitis in rats].

OBJECTIVE: To observe the suppressive effects of immunostimulatory DNA sequences (ISS) in conjunction with dermato phalloides farinae allergen (Df) on nasal cavity inflammation in rats of experimental allergic rhinitis (AR). METHOD: Thirty-two rats were divided into 4 groups: group ISS(A), group ISS+ Df (B), group Df (C) and group normal saline (D). Rats in groups A,B and C were sensitized and challenged with Df. Blood samples were obtained every week for six weeks, Df specific IgE was measured by ELISA. The nasal mucosa were studied pathologically. The levels of serum interferon gamma (IFN-gamma), IL-12, IL-4 and IL-5 were determined by ELISA. RESULT: The serum level of sIgE in group B was significantly lower than that in group C in six weeks, but that in group A was not significantly different to that in group C. The mean levels of serum IFN-gamma and IL-12 in A, B group were significantly higher than in C group (P < 0.01). But IL-4 and IL-5 level was much lower (P < 0.01). CONCLUSION: ISS+ Df have inhibited effectiveness on allergic nasal cavity inflammation in rats and its action time is 6 weeks.

[Human pot1 gene exon12 mutation screening in cultured human carcinoma cell strains (lines)].

OBJECTIVE: To screen the exon12 mutation of pot1 gene in cultured human carcinoma cell strains (lines). METHODS: The chromosomal DNA was extracted from 27 cultured carcinoma cell strains (lines). The exon 12 of pot1 gene was amplified by PCR, and the product was purified and screened. The screening results were compared with the data of GenBank and NCBI and the exon 12 mutations in cultured human carcinoma cell strains (lines) analyzed. RESULTS: The exon12 sequence of pot1 could be specifically amplified using the designed primers. Direct sequence analysis of the PCR products after purification showed that 4 of the 5 carcinoma cell lines of the female genital system such as Hela and HO8910-PM cells shared the same transition (G17722-->C) in exon12 of human pot1 gene resulting in a conversion of G1385-->C in the cDNA and amino acid change of Leu454-->Phe in the translated polypeptide. The rest of the 23 cell strains (lines) from different origins showed no such mutation. CONCLUSION: The exon12 (17,722 bp) is a mutant region specific for female genital system tumor.