AuPt Nanodonuts as a Novel Coreaction Accelerator and Luminophore for a Label-free Electrochemiluminescence Aptasensor.

Novel and effective coreaction accelerators are of great importance in electrochemiluminescence (ECL) systems. In this work, novel AuPt nanodonuts, i.e., SnS2 quantum dots (QDs)/Cys-AuPt heterogeneous nanorings (NRs), serve as both a highly effective coreaction accelerator and the luminophore in a label-free ECL aptasensor. The novel AuPt nanodonuts were formed by decorating SnS2 QDs onto AuPt NR surfaces, which would promote the production of more coreactant intermediate in the SnS2 QDs/K2S2O8 system. As a result, the ECL performance was greatly improved. Meanwhile, l-cysteine (l-Cys) played an important role in the combination between AuPt NRs and SnS2 QDs, and the nanodonuts served as the matrix to load numerous lincomycin (Lin) aptamers. Under optimal conditions, the ECL aptasensor exhibited ultrasensitive detection of Lin from 1 fg/mL to 0.1 pg/mL with a limit of detection (LOD) of 0.7 fg/mL (1.72 fM).

Integration of transcriptomics and proteomics to elucidate inhibitory effect and mechanism of rosmarinic acid from Perilla frutescens (L.) Britt. in treating Trichophyton mentagrophytes.

BACKGROUND: Dermatophyte caused by Trichophyton mentagrophytes is a global disease with a growing prevalence that is difficult to cure. Perilla frutescens (L.) Britt. is an edible and medicinal plant. Ancient books of Traditional Chinese Medicine and modern pharmacological studies have shown that it has potential anti-fungi activity. This is the first study to explore the inhibitory effects of compounds from P. frutescens on Trichophyton mentagrophytes and its mechanism of action coupled with the antifungal activity in vitro from network pharmacology, transcriptomics and proteomics. METHODS: Five most potential inhibitory compounds against fungi in P. frutescens was screened with network pharmacology. The antifungal activity of the candidates was detected by a broth microdilution method. Through in vitro antifungal assays screening the compound with efficacy, transcriptomics and proteomics were performed to investigate the pharmacological mechanisms of the effective compound against Trichophyton mentagrophytes. Furthermore, the real-time polymerase chain reaction (PCR) was applied to verify the expression of genes. RESULTS: The top five potential antifungal compounds in P. frutescens screened by network pharmacology are: progesterone, luteolin, apigenin, ursolic acid and rosmarinic acid. In vitro antifungal assays showed that rosmarinic acid had a favorable inhibitory effect on fungi. The transcriptomic findings exhibited that the differentially expressed genes of fungus after rosmarinic acid intervention were mainly enriched in the carbon metabolism pathway, while the proteomic findings suggested that rosmarinic acid could inhibit the average growth of Trichophyton mentagrophytes by interfering with the expression of enolase in the glycolysis pathway. Comparison of real-time PCR and transcriptomics results showed that the trends of gene expression in glycolytic, carbon metabolism and glutathione metabolic pathways were identical. The binding modes and interactions between rosmarinic acid and enolase were preliminary explored by molecular docking analysis. CONCLUSION: The key findings of the present study manifested that rosmarinic acid, a medicinal compound extracted from P. frutescens, had pharmacological activity in inhibiting the growth of Trichophyton mentagrophytes by affecting its enolase expression to reduce metabolism. Rosmarinic acid is expected to be an efficacious product for prevention and treatment of dermatophytes.

The role of autophagy in the treatment of colon cancer by chlorin e6 photodynamic therapy combined with oxaliplatin.

BACKGROUND: Photodynamic therapy is a tumour treatment method. Its mechanism mainly induces apoptosis, autophagy, and other ways to cause cell death. Therefore, this study aims to evaluate the therapeutic effect of chlorine e6 photodynamic therapy (Ce6-PDT) combined with oxaliplatin (L-OHP) in colon cancer and to investigate the role of autophagy in L-OHP treatment and Ce6-PDT combined with L-OHP in colon cancer. METHODS: CCK-8 assay, Scratch wound healing assay, and Western Blot (WB) were used to identify drug-resistant colon cancer cell line SW620/L-OHP. Annexin V/FITC assay, laser confocal double immunofluorescence staining method and WB were employed to investigate the apoptosis and autophagy changes in Ce6-PDT combined with L-OHP. RESULTS: Drug resistance cells SW620/L-OHP were developed under the continuous multi-generation of L-OHP treatment, and the expression of ATP-binding cassette subfamily B member 1 (ABCB1) and ATG5 proteins were increased. The results of immunofluorescence showed that LC3B accumulated in SW620 cells and SW620/L-OHP cells under the treatment of L-OHP. The WB results indicated that LC3B and ATG5 protein expression was increasing in SW620 cells and SW620/L-OHP cells. Inhibition of L-OHP-induced autophagy reduces SW620 cells and SW620/L-OHP cells' viability while increasing apoptosis and the Pro Caspase-3 protein expression. The combination of Ce6-PDT and L-OHP decreased the cell viability, the cell migration ability, the Bcl-2 protein expression, and increased the apoptosis rate, Pro Caspase-3 protein expression in SW620 cells. CONCLUSIONS: L-OHP can cause SW620 cells drug resistance. Autophagy plays a protective role in the L-OHP treatment of SW620 cells and SW620/L-OHP cells, and inhibition of autophagy can increase the efficacy of L-OHP. Ce6-PDT combined with L-OHP can further improve the tumor's therapeutic effect, and autophagy inhibition can improve the efficacy of combined therapy.

Novel Dual-Signal Electrochemiluminescence Aptasensor Involving the Resonance Energy Transform System for Kanamycin Detection.

Based on luminol-capped Pt-tipped Au bimetallic nanorods (NRs) (L-Au-Pt NRs) as the anode emitter and SnS2 quantum dots (QDs) hybrid Eu metal organic frameworks (MOFs) (SnS2 QDs@Eu MOFs) as the cathode emitter, a dual-signal electrochemiluminescence (ECL) platform was designed for the ultrasensitive and highly selective detection of kanamycin (KAN). Using a dual-signal output mode, the ratiometric ECL aptasensor largely eliminates false-positives or false-negatives by self-calibration in the KAN assay process. To stimulate the resonance energy transform (RET) system, the KAN aptamer and complementary DNA are introduced for conjugation between the donor and acceptor. With the specific recognition of target KAN by its aptamer, L-Au-Pt NRs-apt partially peels off from the electrode surface. Eventually, the RET system is removed, leading to an increasing cathode signal and a decreasing anode signal. In view of this phenomenon, the ratiometric aptasensor can quantify KAN from 1 pM to 10 nM with a low detection limit of 0.32 pM. This dual-signal ECL aptasensor exhibits great practical potential in environmental monitoring and food safety.

Plasmon-Enhanced Electrochemiluminescence of PTP-Decorated Eu MOF-Based Pt-Tipped Au Bimetallic Nanorods for the Lincomycin Assay.

Plasmonic bimetal nanostructures can be employed to amplify electrochemiluminescence (ECL) signals. In this work, a high-performance ECL platform was constructed using a europium metal-organic framework (MOF) as a luminophore and Au-Pt bimetallic nanorods (NRs) as a plasma source. Due to the SPR effect of Au-Pt NRs, the aptasensor exhibits 2.6-fold ECL intensity compared to that of pure polyaniline (PANI)-decorated perylene tetracarboxylic dianhydride (PTCA)/Eu MOF. Moreover, decoration with PTP greatly enhances the conductivity and stability of Eu MOF, resulting in sizeable plasmon-enhanced electrochemical luminescence. The as-designed plasmon-enhanced ECL aptasensor displayed highly sensitive detection for lincomycin (Lin). The as-proposed aptasensor could quantify Lin from 0.1 mg/mL to 0.1 ng/mL with a limit of detection (LOD) of 0.026 ng/mL.

A Novel Metabolite as a Hapten to Prepare Monoclonal Antibodies for Rapid Screening of Quinoxaline Drug Residues.

Quinoxalines (Qx) are chemically synthesized antibacterial drugs with strong antibacterial and growth-promoting effects. Qx is heavily abused by farmers, resulting in large residues in animal-derived foods, which pose a serious threat to human health. Desoxyquinoxalines (DQx), which have the highest residue levels, have been identified as the major toxicant and have become a new generation of residue markers. In this study, we prepared monoclonal antibodies (mAb) based on a new generation metabolite (desoxymequindox, DMEQ) and establish an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) for the rapid determination of Qx residues in food. The mAb exhibited high sensitivity with half maximal inhibitory concentration (IC50) and a linear range of 2.84 µg/L and 0.8-12.8 µg/L, respectively. Additionally, the cross-reactivity (CR) of the mAb showed that it recognized multiple DQx to varying levels. The limits of detection (LOD), limits of quantification (LOQ), and recoveries for the ic-ELISA assay of pork, swine liver, swine kidney, chicken, and chicken liver were 0.48-0.58 µg/kg, 0.61-0.90 µg/kg, and 73.7-107.8%, respectively, and the coefficients of variation (CV) were less than 11%. The results of the ic-ELISA showed a good correlation with LC-MS/MS in animal-derived foods. This suggests that this analytical method can be used for the rapid screening of QX residues.

Have anthropogenic factors mitigated or intensified soil erosion over the past three decades in South China?

As a form of land degradation, soil erosion directly threatens the sustainability of natural resources and the environment. The impacts of humans on soil erosion are profound and complex, especially in the areas with frequent human activities. Moreover, the great variability of human activities at the spatial and time scales precludes a comprehensive understanding of how humans affect regional erosion. This study evaluated soil erosion by water from 1985 to 2015 occurring in South China, which is densely populated and has been intensively exploited, based on the Chinese Soil Loss Equation (CSLE) and multisource data including remote sensing images, meteorological station information and geographic data. A quantitative method combining traceability thinking and residual trend approach was employed to distinguish the relative contributions of climate change and human activities. The results showed that the average amount of soil erosion exhibited a significant decreasing trend from 1985 to 2015, which was consistent with the national water census data and previous studies. Anthropogenic factors played a more vital role than natural variables in the evolution of soil erosion, the multiyear average contribution of which was 63.90%. The area in which anthropogenic factors alleviated soil erosion covered approximately 83.70% of the study area. These results indicate that soil and water conservation practices have made outstanding contributions to the reduction of soil erosion in South China. However, the impacts of the expansion of building land and the development of plantations on aggravating soil erosion cannot be ignored. For future soil erosion control, we observed the diminishing marginal effect of investments in soil and water conservation, and a higher governance potential in the severely eroded regions, which made the severely eroded poor land a primary for comprehensive ecological management. This study aims to provide valuable insights for decision makers in South China to better understand the impacts of humans on the evolution of soil erosion and could provide scientific support for reducing regional soil loss and enhancing the sustainable development of the ecological environment.

Inhibition of autophagy enhances apoptosis induced by Ce6-photodynamic therapy in human colon cancer cells.

OBJECTIVE: To evaluate the therapeutic effect of Chlorin e6 photodynamic therapy (Ce6-PDT) in human colorectal cancer cells and investigate the role of autophagy in Ce6-PDT. METHODS: SW480 cells underwent Ce6-PDT with and without pretreatment with the autophagy inhibitor 3-methyladenine (3MA). Cell viability was assessed using 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Apoptosis was evaluated using an Annexin V assay, using a rhodamine 123 (RH123) assay to evaluate mitochondrial membrane potential (MMP), and by measuring Caspase-3 and Bcl-2 protein expression using western blotting. Autophagy was evaluated by directly visualizing acridine orange-stained acidic vesicular organelles (AVOs) using fluorescent microscopy and by measuring LC3Ⅰ/Ⅱand Atg5 expression using western blotting. RESULTS: Ce6-PDT decreased SW480 viability in a dose-dependent manner. Ce6-PDT induced apoptosis in SW480 cells via the mitochondrial apoptosis pathway as indicated by decreased mitochondrial membrane potential, increased Annexin V staining, and increased Caspase-3 expression. Ce6-PDT was also shown to induce autophagy as demonstrated by increased acridine-orange stained AVOs as well as increased expression of the autophagy-associated proteins Atg5. Inhibition of autophagy with 3MA potentiated SW480 cell response to Ce6-PDT and increased the rate of apoptosis in the treated cells. CONCLUSIONS: Ce6-PDT induces autophagy and apoptosis of SW480 cells in a dose-dependent manner. Inhibition of autophagy increases the apoptosis induced by Ce6-PDT. Modulation of autophagy may be a potential therapeutic target for colon cancer cells treated with Ce6-PDT.

Effects of jasplakinolide on cytotoxicity, cytoskeleton and apoptosis in two different colon cancer cell lines treated with m-THPC-PDT.

Colorectal cancer (CRC) is a common malignant tumor, and metastasis is one of the most important challenges in the treatment of CRC. Photodynamic therapy (PDT) is a novel and non-invasive treatment that influence cytoskeleton and to reduce cancer metastases. In addition, cytoskeleton is related to cancer metastases. Two isogenic colorectal cancer cell lines SW480 and SW620 were used in the present study, we found that m-THPC mediated PDT changed the cytotoxicity, apoptosis and cytoskeleton in both cell lines. Interestingly, the expression of intermediate filaments protein cytokeratin18 were different in the two cell lines. In order to further confirm the relationship between cytoskeleton and cell migration, we combined with microfilament stabilizer jasplakinolide (JASP) to observe the effects of microfilaments on cell migration, cytotoxicity and apoptosis. Taken together, these findings suggest that m-THPC-PDT could induce cytoplasmic cytoskeleton destruction in both types of cells, especially on microfilaments and microtubules. Moreover, in SW480 cells, microtubules may participate in the apoptosis process induced by m-THPC-PDT, while microfilaments may participate in the process of m-THPC-PDT inhibiting cell migration. But in SW620 cells, only microfilaments may be involved in m-THPC-PDT induced apoptosis and inhibition of cell migration.

Photodynamic effect of chlorin e6 on cytoskeleton protein of human colon cancer SW480 cells.

BACKGROUND: Photodynamic therapy (PDT) is based on photochemical and photobiological reactions mediated by photosensitizers to achieve a killing effect on diseased cells. It is used in the treatment of malignant tumors, precancerous lesions and infections. OBJECTIVE: In order to provide theoretical data for further study of the mechanism of PDT for colorectal cancer, SW480 cells were treated with Ce6-PDT and effect of photodynamic therapy (Ce6-PDT) on cytoskeleton and E-cadherin protein were observed. METHODS: The survival of SW480 cells was detected by MTT assay. The morphological changes of SW480 cells after Ce6-PDT were observed by scanning electron microscope (ESM). The migration ability was determined by wound healing assay. The distribution of F-actin in the cytoplasm was observed with confocal laser scanning microscope. Western blot analysis was used to detect the expression of cytoskeleton proteins in SW480 cells after Ce6-PDT. RESULTS: Compared with the control group, there was significant difference in cell viability of cells treated with Ce6-PDT (F = 78753.78, P < 0.05). The pseudopodia almost disappeared and cellular atrophy was clearly visible in the cells of Ce6-PDT group. The migration ability of cells treated with Ce6-PDT for 48 h was significantly lower than the control group (F = 11.794, P<0.001). The result of Western blot analysis showed that the expression of F-actin, α-tubulin, ß-tubulin and Vimentin in the cells treated with Ce6-PDT were significantly higher than that in the control group (F = 22.251,8.109, 5.840, 4.685 and 18.754, P < 0.05). The expression of E-cadherin in cells of Ce6-PDT group was significantly higher than that in control group (F = 30.882, P < 0.001). Perhaps Ce6-PDT inhibits the proliferation and migration of colon cancer SW480 cells by enhancing the expression of E-cadherin, causing the disappearance of cell pseudopodia and the destruction of cytoskeleton. CONCLUSIONS: The destruction of cytoskeleton might be one of the reasons for the inhibition of cell proliferation and migration by Ce6-PDT.

Downregulation of Rac1/PAK1/LIMK1/cofilin signaling pathway in colon cancer SW620 cells treated with Chlorin e6 photodynamic therapy.

BACKGROUND: Colorectal cancer is one of the most common gastrointestinal malignancies. Photodynamic therapy (PDT) is a novel and non-invasive treatment for tumors as PDT features small trauma, good applicability, andaccurate targeting. PDT may also be a potential treatment for colon cancer as itmay may induce suppressive effects on metastatic potential.. However, the molecular mechanism of the Chlorin e6 Photodynamic therapy (Ce6-PDT) inhibiting the migration of human colon cancer SW620 cells remains unclear. METHODS: Scratch wound healing assay, scanning electron microscope, MTT, immunofluorescence and laser confocal technique were used to investigate the suppressive effects of Ce6-PDT on the SW620 cells migration, pseudopodia, viability and the actin cytoskeleton. The effect of Ce6-PDT on actin-Filaments and signaling molecules of the Rac1/PAK1/LIMK1/cofilin signaling pathway in SW620 cells were examined by western blot analysis. RNA interference (RNAi) technology was used to establish siRNA-Rac1/SW620 cells. The combined effects of Ce6-PDT and RNAi on colon cancer SW620 cells was investigated by the same technology and methods mentioned above to clarify the signal transduction effect of Rac1/PAK1/LIMK1/cofilin signaling pathway in Ce6-PDT caused inhibition of SW620 cell migration. RESULTS: The healing and migration rate of the SW620 cells was significantly reduced and the cell pseudopodia were reduced or disappeared by Ce6-PDT. The Immunofluorescence and western blot analysis results showed that Ce6-PDT destroy microfilament's original structure and significantly downregulated F-actin protein expression. The Rac1/PAK1/LIMK1/cofilin signaling pathway was downregulated by Ce6-PDT. Furthermore, the RNAi significantly strengthened the effect of Ce6-PDT on colon cancer SW620 cells migration. CONCLUSIONS: Actin cytoskeleton and protrusions of SW620 cells correlate with its migration ability. Ce6-PDT suppresses SW620 cells migration by downregulating the Rac1/PAK1/LIMK1/cofilin signaling pathway, and its suppressive effect was enhanced by knocking down Rac1 gene expression.

Enhanced cytotoxicity and apoptosis through inhibiting autophagy in metastatic potential colon cancer SW620 cells treated with Chlorin e6 photodynamic therapy.

Photodynamic therapy (PDT) is a novel and non-invasive treatment that induces apoptosis and autophagy. Autophagy could play a pro-survival role, thus inhibiting autophagic activity might be a promising method to enhance the effectiveness of PDT for tumors. In the present study, photosensitizer Chlorin e6 (Ce6) was found to mainly locate in endoplasmic reticulum, and to a lesser extent in mitochondria and lysosome. Chlorin e6 photodynamic therapy (Ce6-PDT) could kill human colon cancer SW620 cells by inducing apoptotic cell death, and autophagy also induced by Ce6-PDT in colon cancer cells. More importantly, autophagy played a pro-survival role. Its inhibition enhanced Ce6-PDT-associated apoptotic cell death because cells pretreated with the typical autophagy inhibitor 3-methyladenine exhibited higher cytotoxicity and apoptotic cell death.

Aqueous norfloxacin sonocatalytic degradation with multilayer flower-like ZnO in the presence of peroxydisulfate.

Multilayer ZnO nanoflowers were synthesized through a simple precipitation method and characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) and nitrogen absorption-desorption techniques. The FE-SEM images show the integrated morphology of an individual flower-like ZnO nanostructure, which is made of nano-platelets with uniform thickness (20-30nm). The average pore size and Brunauer-Emmet-Teller (BET) surface area of the as-synthesized ZnO were 27.25nm and 13.53m2/g. The sonocatalytic ability of the prepared samples was evaluated through norfloxacin (NF) degradation in an aqueous system using ultrasound (US) irradiation. To improve degradation efficiency, peroxydisulfate (Na2S2O8) was introduced to develop a US/ZnO/peroxydisulfate system, which exhibited an excellent synergistic effect. The effects of ZnO dosage, Na2S2O8 concentration, pH, and initial NF concentration were studied to determine the performances of the US/ZnO/peroxydisulfate process. Corresponding results showed that NF degradation rate increased with the increase of ZnO dosage but decreased with the increase of initial NF concentration. Under the optimal Na2S2O8 concentration of 0.1gL-1 at pH 9, the best degradation efficiency can be achieved. Moreover, based on the scavenging experiment results and literatures, NF degradation through US/ZnO/peroxydisulfate system is majorly induced by OH and SO4- radicals.

Removal of aqueous oxalic acid by heterogeneous catalytic ozonation with MnOx/sewage sludge-derived activated carbon as catalysts.

MnOx/sewage sludge-derived activated carbon (MnOx/SAC) was prepared as catalysts to improve the performance of aqueous oxalic acid degradation by ozonation. The results indicated that MnOx/SAC had excellent catalytic activity in mineralization of oxalic acid during heterogeneous catalytic ozonation process. MnOx/SAC with a manganese load of 30% exhibited the strongest catalytic activity under the condition of solution pH3.5, which enhanced the oxalic acid removal from 10.3% to 92.2% in 60min compared with that treated by ozone alone. Increase of catalyst dosage and aqueous ozone concentration was advantageous for oxalic acid removal from water. On the basis of catalyst characterization analysis and the observation of inhibitory effect induced by higher pH, less catalyst dosage as well as the presence of hydroxyl radical scavenger, it was deduced that the reaction mechanism involved both hydroxyl radicals attack and surface reactions.