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1.
J Hazard Mater ; : 121727, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31796366

RESUMO

Bisphenol A (BPA), a widely distributed organic compound, is toxic to animals and plants. Here we show the mechanism of BPA detoxification by melatonin (MEL) in tomato, which is otherwise poorly understood in plants. BPA treatment decreased the quantum yield of photosystem II (Fv/Fm) and increased the membrane lipid peroxidation and reactive oxygen species (ROS) accumulation dose-dependently, whereas exogenous MEL alleviated the BPA effects on Fv/Fm, lipid peroxidation, ROS accumulation and BPA uptake. Furthermore, BPA elevated the glutathione (GSH) content, activities of glutathione S-transferase (GST), and glutathione reductase (GR), and the transcript levels of GSH1, GR1, GST1 and MEL biosynthesis genes (COMT, T5H, and SNAT), whereas BPA + MEL showed even a more profound induction. Silencing GSH1, GR1 and GST1 genes compromised the BPA detoxification potential of tomato plants as revealed by an increased level of ROS, lipid peroxidation and BPA uptake, and a decreased Fv/Fm and GST activity; these changes were alleviated by MEL application. Under in vitro conditions, BPA was glutathionylated by GSH, which was further catalyzed by GST to cysteine and N-acetylcysteine conjugates. These findings suggest a crucial role for MEL in BPA detoxification via GSH and GST, and can be useful to reduce BPA residue for food safety.

2.
BMC Cardiovasc Disord ; 19(1): 273, 2019 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-31783792

RESUMO

BACKGROUND: The interventional treatment of chronic total occlusion (CTO) with stent fracture as well as severe calcification was extremely difficult and no effective technique has been reported. CASE PRESENTATION: A 50-year-old woman was hospitalized for angina, angiography revealed triple vessel disease, CTO accompanied with stent fracture in right coronary artery (RCA). Treatment using conventional coronary intervention was expected to be difficult. Therefore, we performed RASER technique, which was a combination of excimer laser coronary atherectomy (ELCA) with rotational atherectomy (RA), followed by the deployment of drug-eluting stents. Intravascular ultrasound (IVUS) revealed well attachment of the stents, the patient was discharged 3 days after the procedure and no recurrent chest discomfort was reported in a follow-up time of 10 months. CONCLUSION: This case report provided a first report of RASER technique in the treatment of CTO with stent fracture and severe calcification.

3.
Aging (Albany NY) ; 112019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31796647

RESUMO

This study aimed to construct immune-related predictors to identify responders to anti-PD1 therapy of melanoma through CIBERSORT algorithm. Using the least absolute shrinkage and selection operator (LASSO) logistic regression, we constructed an immunoscore consisting of 8 immune subsets to predict the anti-PD1 response. This score achieved an overall accuracy of AUC = 0.77, 0.80 and 0.73 in the training cohort, validation cohort and on-anti-PD1 cohort, respectively. Patients with high immunoscores had significantly higher objective response rates (ORRs) than did those with low immunoscores (ORR: 53.8% vs 17.7%, P < 0.001 for entire pre-anti-PD1 cohort; 42.1% vs 15.1%, P = 0.022 for on-anti-PD1 cohort; 66.7% vs 16.7%, P = 0.038 for neoadjuvant anti-PD1 cohort). Prolonged survival trends were observed in high-immunoscore group (1-year PFS: 42.4% vs 14.3%, P = 0.059; 3-year OS: 41.5% vs 31.6%, P = 0.057). Furthermore, we found that high-immunoscore group exhibited higher fractions of tumor-infiltrating lymphocytes and an increased IFN-γ response. Analysis of the results of the GSEA indicated a significant enrichment of antitumor immunity pathways in the high-immunoscore group. Therefore, this study indicated that we constructed a robust immunoscore model to predict the anti-PD1 response of metastatic melanoma and the neoadjuvant anti-PD1 response of resectable melanoma.

4.
Mol Med Rep ; 2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31789407

RESUMO

Rearrangement of the mixed lineage leukemia (MLL; also known as lysine methyltransferase 2A) gene is a recurrent genomic aberration in acute myeloid leukemia (AML). MLLT3, super elongation complex subunit (AF9) is one of the most common MLL fusion partners in AML. The present study aimed to explore the aberrant expression of genes associated with the MLL­AF9 translocation and identified potential new targets for the therapy of AML with MLL­AF9 translocation. The transcriptomic and epigenetic datasets were downloaded from National Center of Biotechnology Information Gene Expression Omnibus (GEO) database. Differentially expressed genes were obtained from two independent datasets (GSE68643 and GSE73457). Gene Ontology biological process and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis was performed using the Database for Annotation, Visualization and Integrated Discovery. MLL­AF9­associated chromatin immunoprecipitation sequencing (ChIP­Seq) data was analyzed and identified binding sites for MLL­AF9 and wild type MLL (MLL WT). The ChIP­Seq of histone modification data was downloaded from the GEO database, including histone 3 lysine 4 trimethylation (H3K4me3), histone 3 lysine 79 dimethylation (H3K79me2) and histone 3 lysine 27 acetylation (H3K27ac), was used for comparing histone modification marks between the MLL­AF9 leukemia cells and normal hematopoietic cells at MLL­AF9 and MLL WT binding sites. The differentially expressed genes with the same trend in H3K79me2, H3K27ac and H3K4me3 alteration were identified as potential MLL­AF9 direct target genes. Upon validation using RNA­Seq data from the Therapeutically Applicable Research to Generate Effective Treatments AML project, eight potential direct target genes of MLL­AF9 were identified and further confirmed in MLL­AF9 mouse model using reverse transcription­quantitative polymerase chain reaction. These genes may have a critical role in AML with MLL­AF9 translocation.

5.
BMC Neurol ; 19(1): 291, 2019 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-31735164

RESUMO

BACKGROUND: Mutations of cyclooxygenase gene (COX gene) may increase the susceptibility of ischemic stroke. We investigated five variants (rs5788, rs1330344, rs3842788, rs20417, and rs689466) of two COX genes in order to explaining the association between these polymorphisms and we also investigated the association between these variants and ischemic stroke risk to determine whether gene-gene interaction between these genes increases the susceptibility of ischemic stroke or its subtypes. METHODS: A total of 1981 study subjects (1078 cases and 903 control subjects) were recruited. The interaction of multiple factors was investigated using Multifactor Dimensionality Reduction. The additive effect of single nucleotide polymorphisms on ischemic stroke or its subtypes were analyzed by multiple factor logistic regression. RESULTS: At COX-1(rs1330344), AA genotype carriers had a lower susceptibility of ischemic stroke (OR = 0.657, 95%CI = 0.437-0.988, P = 0.044), and A allele carriers had a lower susceptibility of ischemic stroke (OR = 0.812, 95%CI = 0.657-0.978, P = 0.029). At COX-1(rs3842788), AA genotype carriers had a higher susceptibility of ischemic stroke (OR = 5.203, 95% CI = 1.519-5.159, P = 0.016). At COX-2 (rs689466), AA genotype carriers had a higher susceptibility of large-artery atherosclerosis (OR = 1.404, 95% CI = 1.019-1.934, P = 0.038). COX-1(rs1330344, rs3842788) and COX-2 rs689466 interacted in SVO, but had no additive effect with ischemic stroke and other subtypes. CONCLUSIONS: At rs1330344, AA genotype may reduce the susceptibility of ischemic stroke. At rs3842788, AA genotype may increase the susceptibility of ischemic stroke. At rs689466, AA genotype may increase the susceptibility of large-artery atherosclerosis (LAA). COX - 1(rs1330344, rs3842788) and COX-2 rs689466 interacted in small vessel occlusion (SVO), but had no additive effect with ischemic stroke and other subtypes.

6.
Biomacromolecules ; 2019 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-31710481

RESUMO

Simultaneous production and functionalization of cellulose nanofibrils (CNFs) for heavy metal ion removal is an economical and promising solution to expedite their use in water treatment. In this work, carboxymethylated CNFs (CMCNFs) with a carboxylate content up to 2.7 mmol/g are prepared by a combination of carboxymethylation and homogenization, which show diameters of 3.40-3.53 nm and lengths of 1210.6-383.3 nm. The effect of experimental conditions (including pH, carboxylate content, contact time, initial Cu2+ concentration) on the removal performance of CMCNFs for Cu2+ is investigated in detail. Adsorption performances of CMCNFs present a record high equilibrium Cu2+ removal capacity of 115.3 mg/g at pH 5.0. Additionally, the underlying mechanism for the removal of Cu2+ ions was uncovered by coupling the fitting results based on pseudo-second-order kinetic and Langmuir isotherm models with various characterizations such as scanning electron microscopy, energy dispersive spectroscopy (EDS), EDS mapping, X-ray photoelectron spectroscopy, atomic force microscopy, and powder X-ray diffraction. Finally, the potential application of CMCNF-2.7 with high carboxylate content in converting copper-contaminated water into drinking water was demonstrated. CMCNFs provide a new selection for the design of novel nanocellulose-based materials for water treatments.

7.
Artigo em Inglês | MEDLINE | ID: mdl-31670672

RESUMO

Learning an effective distance measurement between sample pairs plays an important role in visual analysis, where the training procedure largely relies on hard negative samples. However, hard negative samples usually account for the tiny minority in the training set, which may fail to fully describe the data distribution close to the decision boundary. In this paper, we present a deep adversarial metric learning (DAML) framework to generate synthetic hard negatives from the original negative samples, which is widely applicable to existing supervised deep metric learning algorithms. Different from existing sampling strategies which simply ignore numerous easy negatives, our DAML aim to exploit them by generating synthetic hard negatives adversarial to the learned metric as complements. We simultaneously train the feature embedding and hard negative generator in an adversarial manner, so that adequate and targeted synthetic hard negatives are created to learn more precise distance metrics. As a single transformation may not be powerful enough to describe the global input space under the attack of the hard negative generator, we further propose a deep adversarial multi-metric learning (DAMML) method by learning multiple local transformations for more complete description. We simultaneously exploit the collaborative and competitive relationships among multiple metrics, where the metrics display unity against the generator for effective distance measurement as well as compete for more training data through a metric discriminator to avoid overlapping. Extensive experimental results on five benchmark datasets show that our DAML and DAMML effectively boost the performance of existing deep metric learning approaches through adversarial learning.

8.
J Inherit Metab Dis ; 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31774565

RESUMO

Classic Galactosaemia is a genetic disorder, characterised by galactose intolerance in newborns. It occurs due to recessive mutations in the galactose-1-phosphate uridylyltransferase (GALT) gene. One of the main alterations caused by GALT deficiency is the accumulation of galactose 1-phosphate (Gal-1P) in cells. Studies have suggested that Gal-1P exerts cellular toxicity, possibly by inhibiting cellular metabolism. However, the exact significance of Gal-1P in disease pathogenesis remains unclear. In this study, we tested the hypothesis that Gal-1P inhibits cellular glucose utilization by competing with substrates in the glycolytic pathway. We also investigated the metabolism of both galactose and glucose in GALT-expressing HEK293T and 143B cells to identify critical reactions steps contributing to the metabolic toxicity of galactose. Notably, we found that galactose-treated HEK293T and 143B cells, which express endogenous GALT, accumulate markedly high intracellular Gal-1P concentrations. Despite very high intracellular Gal-1P concentrations, no inhibition of cellular glucose uptake and no significant changes in the intracellular concentrations of glycolytic metabolites were observed. This indicates that Gal-1P does not exert an inhibitory effect on glycolysis in cells and rules out one potential hypothesis for cellular Gal-1P toxicity. We also investigated the mechanism responsible for the observed Gal-1P accumulation. Our results suggest that Gal-1P accumulation is a result of both low GALT activity and the absence of product inhibition by Gal-1P on galactokinase (GALK1), the enzyme responsible for phosphorylating galactose to Gal-1P. These findings provide a better understanding of the disease mechanisms underlying Classic Galactoaemia. This article is protected by copyright. All rights reserved.

9.
Int Immunopharmacol ; : 106026, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31759863

RESUMO

Diet is one of the factors contributing to symptom of Helicobacter pylori (H. pylori) infection. Trimethylamine N-oxide (TMAO), a diet-related microbial metabolite, is associated with inflammatory and metabolic diseases. The aim of this study is to investigate the effects of TMAO intake on inflammation and gut microbiota composition in H. pylori-infected mice via 16S rRNA sequencing and biochemical analyses. The in vitro experiments showed that TMAO not only increased the expression of growth- and metabolism-associated genes and the urease activity of H. pylori, but increased the production of virulence factors. Moreover, TMAO intake increased the production of inflammatory markers and reduced the richness and diversity of the gut microbiota in H. pylori-infected mice. Further analysis showed that TMAO increased the relative abundance of Escherichia_Shigella in H. pylori-infected mice, which had positive correlation with the levels of LPS, CRP, and CXCL1. Collectively, our results suggest that TMAO may aggravate H. pylori-induced inflammation by increasing the viability and virulence of H. pylori and may aggravate inflammation in association with the gut microbiota in H. pylori-infected mice. This study may provide a novel insight into the mechanism for the effect of diet-derived metabolites such as TMAO on H. pylori-induced disease development.

10.
Inorg Chem ; 2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31762286

RESUMO

Visible-light driven photoreactions using metal-organic frameworks (MOFs) as catalysts are promising with regard to their environmental friendly features such as the use of renewable and sustainable energy of visible light and potential catalyst recyclability. To develop potential heterogeneous photocatalysts, a family of three copper(II) coordination polymers bearing different Cu-O assemblies have been synthesized with the ligand 4,4'-disulfo-[1,1'-biphenyl]-2,2'-dicarboxylate acid (H4DSDC), namely, {[Cu7(DSDC)2(OH)6(H2O)10]·xH2O}n (1), {[Cu4(DSDC)(4,4'-bpy)2(OH)4]·2H2O}n (2), and {Cu2(DSDC)(phen)2(H2O)2}n (3) (4,4'-bpy = 4,4'-bipyridine and phen = 1,10-phenanthroline). Complex 1 represents a metal-organic framework featuring a NbO type topology constructed from the infinite linkage of heptanuclear [Cu7(µ3-OH)6(H2O)10]8+ clusters by deprotonated DSDC4- ligands, comprising one-dimensional hexagonal channels of a diameter around 11 Å that are filled with water molecules. The infinite waving {[Cu2(OH)2]2+}n ladderlike chains in complex 2 are bridged by DSDC4- and 4,4'-bpy ligands into a three-dimensional framework. A two-dimensional layered structure is formed in complex 3 due to the existence of terminal phenanthroline ligands. All of the coordination polymers 1-3 are able to catalyze the visible-light driven oxidation of alcohols at mild conditions using hydrogen peroxide as an oxidant, in which complex 1 demonstrates satisfactory efficiency. Significantly for this photoreaction catalyzed by 1, the extent of oxidation over aryl primary alcohols is fully controllable with time-resolved product selectivity, giving either corresponding aldehydes or carboxylate acids in good yields. It is also remarkable that the photocatalyst could be recovered almost quantitatively on completion of the catalytic cycle without any structure change, and could be recycled for catalytic use for at least five cycles with constant efficiency. This photocatalyst with time-resolved selectivity for different products may provide new insight into the design and development of novel catalytic systems.

11.
Gastrointest Endosc ; 2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31783029

RESUMO

BACKGROUND AND AIMS: The quality of bowel preparation is an important factor that can affect the effectiveness of a colonoscopy. Several tools, such as the Boston Bowel Preparation Scale (BBPS) and Ottawa Bowel Preparation Scale, have been developed to evaluate bowel preparation. However, understanding the differences between evaluation methods and consistently applying them can be challenging for endoscopists. There are also subjective biases and differences among endoscopists. Therefore, this study aimed to develop a novel, objective, and stable method for the assessment of bowel preparation through artificial intelligence. METHODS: We used a deep convolutional neural network to develop this novel system. First, we retrospectively collected colonoscopy images to train the system and then compared its performance with endoscopists via a human-machine contest. Then, we applied this model to colonoscopy videos and developed a system named ENDOANGEL to provide bowel preparation scores every 30 seconds and to show the cumulative ratio of frames for each score during the withdrawal phase of the colonoscopy. RESULTS: ENDOANGEL achieved 93.33% accuracy in the human-machine contest with 120 images, which was better than that of all endoscopists. Moreover, ENDOANGEL achieved 80.00% accuracy among 100 images with bubbles. In 20 colonoscopy videos, the accuracy was 89.04%, and ENDOANGEL continuously showed the accumulated percentage of the images for different BBPS scores during the withdrawal phase and prompted us for bowel preparation scores every 30 seconds. CONCLUSIONS: We provided a novel and more accurate evaluation method for bowel preparation and developed an objective and stable system-ENDOANGEL-that could be applied reliably and steadily in clinical settings.

12.
Food Chem ; : 125895, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31780220

RESUMO

Pile-fermentation is the most important process of producing ripened pu-erh tea. To study the chemical changes of tea leaves during pile-fermentation (PF), liquid chromatography coupled with tandem mass spectrometry (LC-MS) was used. Untargeted metabolomics analysis revealed that the first stage of PF is crucial in transforming the original secondary metabolites, whereas the contents of flavan-3-ols and gallic acid were decreased after long-term PF. Targeted metabolomics analysis indicated that the levels of puerins (N-ethyl-2-pyrrolidinone substituted gallocatechin and catechin) were significant increased after the first stage of PF, but after long-term PF the levels of flavonol glycosides, procyanidins and galloylated flavan-3-ols were significantly decreased. Accordingly, long-term PF also decreased the inhibition of α-amylase and α-glucosidase activities of the extracts. As a conclusion, pile-fermentation is an important step of changing the polyphenols and bioactivities of pu-erh tea.

13.
Analyst ; 2019 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-31781712

RESUMO

CD44 is a promising biomarker in the diagnosis and prognosis of malignancies. The serum CD44 level is closely related to disease progression and metastasis of malignancies. It is of great clinical significance for the detection of serum soluble CD44. In this study, a facile, label-free aptamer based electrochemical impedance sensor for serum CD44 has been proposed. The aptamer showing high affinity to CD44 was immobilized on the gold electrodes through Au-S interaction. The interaction between target CD44 and the immobilized aptamer will cause a complex structure change of the aptamer, which makes the diffusion of [Fe(CN)6]3-/4- toward the electrode surface easy, thus resulting in the decrease of the impedance of the system. The decreased degree of the impedance had a good linear relationship with the logarithm of the CD44 concentration in the range of 0.1-1000 ng mL-1 with a detection limit of 0.087 ng mL-1 (S/N = 3). The developed biosensor has been applied to detect CD44 in serum samples with satisfactory results.

14.
Food Chem ; : 125819, 2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31732248

RESUMO

The well-known red color change plays a significant role in consumer acceptability of crustacean species. In this study, we described the purification of the red color-related protein named MjRCP75 from the shell of Marsupenaeus japonicus. It was a homogeneous monomer with molecular mass of 75 kDa and rich in α-helix conformation. The α-helix content decreased within the increasing of heating temperature and was transformed dominantly to ß types. Identification and structural analysis revealed that MjRCP75 belonged to hemocyanin family. The released pigment from heated MjRCP75 showed a λmax at 483 nm in acetone. MjRCP75 showed clearly antibacterial activity against Escherichia coli, Staphylococcus aureus, and Vibrio parahaemolyticus. These findings identify MjRCP75 as the red color-related protein in M. japonicus shell and reveal its involvement in antibacterial activities.

15.
Theriogenology ; 2019 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-31733931

RESUMO

The aim of this study was to investigate the effects of different oxygen (O2) concentrations on the growth of mouse spermatogonial stem cells (SSCs) and the possible mechanisms of cell proliferation in vitro. The SSCs from testicular cells were cultured in various O2 concentrations (1%, 2.5%, 5%, and 20% O2) for 7 days. Colonies of SSCs were identified morphologically and by immunofluorescence. The number of mouse SSC colonies and the area covered by them were measured. Cell cycle progression of the SSCs was analyzed to identify the state of cell proliferation. The effects of O2 concentrations on the levels of intracellular reactive oxygen species (ROS) and expression of ATP binding cassette subfamily G member 2 (ABCG2) were also analyzed in the SSCs. Following culturing for 7 days, the SSCs were treated with Ko143 (a specific inhibitor of ABCG2) for 1 h, and the ROS level and expression of bcl-2, bax, and p53 were analyzed. The results showed that mouse SSCs formed compact colonies and had unclear borders in different O2 concentrations for 7 days, and there were no major morphologic differences between the O2 treatment groups. The expression of the SSC marker, GFR α1 was studied in each O2 treatment group. The number and area of SSC colonies, and the number of GFR α1 positive cells were the highest in the 2.5% O2 treatment group. Compared with other O2 concentrations, the number of cells in G0 cycle was significantly higher, while the level of intracellular ROS was lower at 1% O2. Moreover, the intracellular ROS levels gradually increased with increasing O2 concentration from 1% to 20%. The expression of ABCG2 in the SSCs cultured at 2.5% O2 was higher than in the other O2 groups. Inhibition of ABCG2 increased intracellular ROS generation, and the expression of the pro-apoptotic genes bax and p53, and decreased the expression of the anti-apoptotic gene bcl-2. In conclusion, moderate to low O2 tension increases ABCG2 expression to maintain mild ROS levels, triggers the expression of the anti-apoptotic genes, suppresses the proapoptotic gene pathway, and further promotes the proliferation of mouse SSCs in vitro.

16.
Sci Data ; 6(1): 247, 2019 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-31672975

RESUMO

Surface soil moisture is a key variable in the exchange of water and energy between the land surface and the atmosphere, and critical to meteorology, hydrology, and ecology. The Tibetan Plateau (TP), known as "The third pole of the world" and "Asia's water towers", exerts huge influences on and sensitive to global climates. In this situation, longer time series of soil moisture can provide sufficient information to understand the role of the TP. This paper presents the first comprehensive dataset (2002-2015) of spatio-temporal continuous soil moisture at 0.25° resolution, based on satellite-based optical (i.e. MODIS) and microwave (ECV) products using a machine learning method named general regression neural network (GRNN). The dataset itself reveals significant information on the soil moisture and its changes over the TP, and can aid to understand the potential driven mechanisms for climate change over the TP.

17.
Mar Pollut Bull ; : 110681, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31699499

RESUMO

Denitrifying anaerobic methane oxidation (DAMO) and associated microbial diversity and abundance in the marsh sediments of Chongming eastern intertidal flat, the Yangtze Estuary, were investigated using carbon-isotope tracing and molecular techniques. Co-existence of nitrate-DAMO archaea and nitrite-DAMO bacteria was evidenced, with higher biodiversity of DAMO archaea than DAMO bacteria. Abundance of DAMO archaeal mcrA gene and DAMO bacterial pmoA gene ranged from 4.2 × 103 to 3.9 × 1010 copies g-1 and from 4.5 × 105 to 6.4 × 106 copies g-1, respectively. High DAMO potential was detected, ranging from 0.6 to 46.7 nmol 13CO2 g-1 day-1 for nitrate-DAMO and from 1.3 to 39.9 nmol 13CO2 g-1 day-1 for nitrite-DAMO. In addition to playing an important role as a CH4 sink, DAMO bacteria also removed a substantial amount of reactive nitrogen (29.4 nmol N g-1 day-1) from the intertidal sediments. Overall, these results indicate the importance of DAMO bioprocess as methane and nitrate sinks in intertidal marshes.

18.
Mol Biotechnol ; 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31749084

RESUMO

DNA cloning is the basic step for different fields of life science, and many efforts have been made to simplify this procedure. In this study, we report two general purpose plasmids (pGP), pGP-XB2E and pGP-B2E, for rapid and cost-effective construct of basic clones. The BciVI and XcmI cleavage sites are designed in pGP-XB2E to test plasmid linearization efficiency. The plasmid has better linearization efficiency by using BciVI which could almost completely digest 2 µg plasmid in 10 min with only one-tenth the recommended enzyme concentration. In order to further optimize the pGP-XB2E, a new plasmid, pGP-B2E, which removed XcmI cleavage site was designed. This vector is highly efficient for cloning PCR products up to 1812 bp, and the number of colonies was about five times that of pGP-XB2E. In addition to TA cloning, blunt-end PCR products with T ended in the primer could be positively linked to the T-vector pGP-B2E without A-tailing treatment (TB cloning). Moreover, as an entry vector, pGP-B2E was also compatible for gateway recombination reaction without frameshift mutations. In general, this vector provides a universal, quick, and cost-efficient method for basic molecular cloning.

19.
Nat Prod Res ; : 1-7, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31674840

RESUMO

A novel monoterpenoid indole alkaloid, melognine (1) possessing an unprecedented skeleton with a 6/6/5/5/6/6 hexatomic rearranged ring system was isolated from the stems of Melodinus fusiformis. The structure with absolute configuration of 1 was established by extensive spectroscopic analyses and quantum ECD calculations. Melognine showed significant cytotoxicity on human breast cancer BT549 cells with an IC50 value of 1.49 µM by MTT assay. Further mechanism of action study indicated that melognine demonstrated the ability to induce apoptosis by activation of caspase-3 and p53, and downregulation of Bcl-2 in BT549 cells.

20.
Anal Chem ; 2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31718153

RESUMO

MicroRNAs (miRNAs) play key roles in many serious diseases, such as cancer. As a consequence, miRNAs are of great interest as biomarkers in clinical diagnostics. Simple, fast, selective, and sensitive detection of miRNAs, however, is challenged by their short length, homogeneous sequence, susceptibility to degradation, and low abundance in human serum. Here, we present a new strategy for highly sensitive and selective detection of miRNA based on the formation of a plasmonic Au@Ag nanosnowman. When triggered by miRNA-21, bimetallic nanoparticles with an asymmetric Au@Ag head-body structure were formed with significant red shift of the localized surface plasmon resonance (LSPR) scattering wavelength and clear color change from green to red. When combined with exonuclease III (Exo III)-assisted target recycling and hybridization chain reaction (HCR) amplification strategy, the proposed bioassay showed excellent selectivity toward miRNA-21 with a proportional band from 1 fM to 100 pM and ultrahigh sensitivity with a limit of detection of 0.60 fM under dark-field microscopy. The proposed strategy is universal, which shows good application prospects in clinical analysis.

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