Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 7 de 7
Filter
Add more filters










Database
Language
Publication year range
1.
Nanomaterials (Basel) ; 14(8)2024 Apr 19.
Article in English | MEDLINE | ID: mdl-38668210

ABSTRACT

In this study, we synthesized a transition metal sulfide (TMS) with a spinel structure, i.e., MnIn2S4 (MIS), using a two-step hydrothermal and sintering process. In the context of lithium-ion battery (LIB) applications, ternary TMSs are being considered as interesting options for anode materials. This consideration arises from their notable attributes, including high theoretical capacity, excellent cycle stability, and cost-effectiveness. However, dramatic volume changes result in the electrochemical performance being severely limited, so we introduced single-walled carbon nanotubes (SWCNTs) and prepared an MIS/SWCNT composite to enhance the structural stability and electronic conductivity. The synthesized MIS/SWCNT composite exhibits better cycle performance than bare MIS. Undergoing 100 cycles, MIS only yields a reversible capacity of 117 mAh/g at 0.1 A/g. However, the MIS/SWCNT composite exhibits a reversible capacity as high as 536 mAh/g after 100 cycles. Moreover, the MIS/SWCNT composite shows a better rate capability. The current density increases with cycling, and the SWCNT composite exhibits high reversible capacities of 232 and 102 mAh/g at 2 A/g and 5 A/g, respectively. Under the same conditions, pristine MIS can only deliver reversible capacities of 21 and 4 mAh/g. The results indicate that MIS/SWCNT composites are promising anode materials for LIBs.

2.
Int J Anal Chem ; 2022: 5834525, 2022.
Article in English | MEDLINE | ID: mdl-36458111

ABSTRACT

Citrus reticulata "Chachi" (CRC) leaves contain abundant flavonoids, indicating that they possess good nutritional/pharmacological research and development potential. This study aims to explore chemical antioxidant quality markers based on the spectrum-effect relationship and quality control strategy of CRC leaves. The ultrahigh performance liquid chromatography (UPLC) system was used to establish chromatographic fingerprints of Citrus reticulata "Chachi" leaves. Simultaneously, they were evaluated by using similarity analysis (SA), hierarchical cluster analysis (HCA), and principal component analysis (PCA). Afterwards, the DPPH assay was adopted to study the antioxidant effects. The spectrum-effect relationship between UPLC fingerprints and DPPH radical-scavenging activities was studied with grey relational analysis (GRA). Analysis results indicated that there were twenty-one common peaks of fourteen batches of CRC leaves which were from different regions of Guangdong province, and their similarities ranged from 0.648 to 0.997. HCA results showed that fourteen batches of samples of CRC leaves could be divided into six classes at Euclidean distance of 5. The results from GRA showed that tangeretin and hesperidin were the main flavonoids responsible for the antioxidant activity in CRC leaves. In conclusion, this research established a chromatographic analysis method suitable for CRC leaves and demonstrated that chromatographic fingerprints analysis combined with the antioxidant activity could be used to evaluate the material basis of CRC leaves and may provide a reference to establish a quality standard.

3.
BMC Genomics ; 13: 619, 2012 Nov 14.
Article in English | MEDLINE | ID: mdl-23151021

ABSTRACT

BACKGROUND: Triple-negative breast cancers (BC) represent a heterogeneous subtype of BCs, generally associated with an aggressive clinical course and where targeted therapies are currently limited. Target validation studies for all BC subtypes have largely employed established BC cell lines, which have proven to be effective tools for drug discovery. RESULTS: Given the lines of evidence suggesting that BC cell lines are effective tools for drug discovery, we assessed the similarities between triple-negative BCs and cell lines, to identify in vitro representatives, modelling the diversity within this BC subtype. 25 BC cell lines, enriched for those lacking ER, PR and HER2 expression, were subjected to transcriptomic, genomic and epigenomic profiling analyses and comparisons were made to existing knowledge of corresponding perturbations in triple-negative BCs. Transcriptional analysis segregated ER-negative BC cell lines into three groups, displaying distinctive abundances for genes involved in epithelial-mesenchymal transition, apocrine and high-grade carcinomas. DNA copy number aberrations of triple-negative BCs were well represented in cell lines and genes with coordinately altered gene expression showed similar patterns in tumours and cell lines. Methylation events in triple-negative BCs were mostly retained in epigenomes of cell lines. Combined methylation and gene expression analyses revealed a subset of genes characteristic of the Claudin-low BC subtype, exhibiting epigenetic-regulated gene expression in BC cell lines and tumours, suggesting that methylation patterns are likely to underpin subtype-specificity. CONCLUSION: Here, we provide a comprehensive analysis of triple-negative BC features on several molecular levels in BC cell lines, thereby creating an in-depth resource to access the suitability of individual lines as experimental models for studying BC tumour biology, biomarkers and possible therapeutic targets in the context of preclinical target validation.


Subject(s)
Breast Neoplasms/genetics , Carcinoma/genetics , Cell Line, Tumor/metabolism , Gene Expression Regulation, Neoplastic , Genomics , Neoplasm Proteins/genetics , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Carcinoma/metabolism , Carcinoma/pathology , Cell Line, Tumor/cytology , Claudins/genetics , Claudins/metabolism , DNA Copy Number Variations , DNA Methylation , Drug Resistance, Neoplasm , Epigenesis, Genetic , Epithelial-Mesenchymal Transition , Female , Gene Expression , Gene Expression Profiling , Humans , Models, Biological , Neoplasm Proteins/metabolism , Receptor, ErbB-2/genetics , Receptor, ErbB-2/metabolism , Receptors, Estrogen/genetics , Receptors, Estrogen/metabolism , Receptors, Progesterone/genetics , Receptors, Progesterone/metabolism
4.
Cell Cycle ; 6(19): 2393-8, 2007 Oct 01.
Article in English | MEDLINE | ID: mdl-17938583

ABSTRACT

The timing of DNA replication generally correlates with transcription, gene density and sequence composition. How is the timing affected if a genomic region has a combination of features that individually correlate with either early or late replication? The major histocompatibility complex (MHC) class II region is an AT-rich isochore that would be expected to replicate late, but it also contains coordinately regulated genes that are highly expressed in antigen-presenting cells and are strongly inducible in other cell types. Using cytological and biochemical assays, we find that the entire MHC replicates within the first half of S-phase, and that the class II region replicates slightly later than the adjacent regions irrespective of gene expression. These data suggest that despite AT-richness, an early-to-middle replication time in the class II region is defined by an open chromatin conformation that allows rapid transcriptional activation as a defence against pathogens.


Subject(s)
DNA Replication Timing , Genes, MHC Class II , Histocompatibility Antigens Class II/metabolism , Interferon-gamma/metabolism , Animals , Cell Line, Tumor , Chromatin Assembly and Disassembly/genetics , Histocompatibility Antigens Class II/genetics , Transcription, Genetic
5.
J Cell Sci ; 120(Pt 18): 3262-70, 2007 Sep 15.
Article in English | MEDLINE | ID: mdl-17726060

ABSTRACT

Transcriptional activation of the major histocompatibility complex (MHC) by IFNgamma is a key step in cell-mediated immunity. At an early stage of IFNgamma induction, chromatin carrying the entire MHC locus loops out from the chromosome 6 territory. We show here that JAK/STAT signalling triggers this higher-order chromatin remodelling and the entire MHC locus becomes decondensed prior to transcriptional activation of the classical HLA class II genes. A single point mutation of STAT1 that prevents phosphorylation is sufficient to abolish chromatin remodelling, thus establishing a direct link between the JAK/STAT signalling pathway and human chromatin architecture. The onset of chromatin remodelling corresponds with the binding of activated STAT1 and the chromatin remodelling enzyme BRG1 at specific sites within the MHC, and is followed by RNA-polymerase recruitment and histone hyperacetylation. We propose that the higher-order chromatin remodelling of the MHC locus is an essential step to generate a transcriptionally permissive chromatin environment for subsequent activation of classical HLA genes.


Subject(s)
Antiviral Agents/pharmacology , Chromatin Assembly and Disassembly/physiology , Interferon-gamma/pharmacology , Major Histocompatibility Complex/physiology , Protein Processing, Post-Translational/physiology , STAT1 Transcription Factor/metabolism , Signal Transduction/physiology , Acetylation/drug effects , Cell Line, Tumor , Chromatin Assembly and Disassembly/drug effects , DNA Helicases/genetics , DNA Helicases/immunology , DNA Helicases/metabolism , Histones/genetics , Histones/immunology , Histones/metabolism , Humans , Immunity, Cellular/drug effects , Immunity, Cellular/physiology , Major Histocompatibility Complex/drug effects , Nuclear Proteins/genetics , Nuclear Proteins/immunology , Nuclear Proteins/metabolism , Phosphorylation/drug effects , Protein Processing, Post-Translational/drug effects , Quantitative Trait Loci/drug effects , Quantitative Trait Loci/physiology , STAT1 Transcription Factor/genetics , STAT1 Transcription Factor/immunology , Signal Transduction/drug effects , Transcription Factors/genetics , Transcription Factors/immunology , Transcription Factors/metabolism , Transcription, Genetic/drug effects , Transcription, Genetic/physiology
6.
Acta Biochim Biophys Sin (Shanghai) ; 37(1): 25-31, 2005 Jan.
Article in English | MEDLINE | ID: mdl-15645078

ABSTRACT

The biological role of DNA1, a nanovirus-like component shown to be associated with the begomovirus/satellite complex, has not yet been identified. Here, we demonstrated that DNA1 of Tobacco curly shoot virus isolate Y35 (TbCSV-Y35) attenuated leaf-curling symptoms induced by TbCSV-Y35 or TbCSV-Y35 plus Y35 DNAbeta in the early stage of symptom development and induced leaf cluster at a later stage of symptom development in Nicotiana benthamiana plants. The leaf disc assay demonstrated that TbCSV-Y35 DNA1 replicated autonomously. Southern blot analysis revealed that TbCSV-Y35 DNA1 reduced viral DNA accumulation. Viral DNA accumulation was not reduced when plants were co-inoculated with TbCSV-Y35 DNAbeta, but the TbCSV-Y35 DNAbeta level was dramatically reduced in the presence of TbCSV-Y35 DNA1. To determine whether the interaction between TbCSV/satellite complex and DNA1 had isolate specificity, DNA1 of TbCSV isolate Y132 was cloned and sequenced. It was found to have 75% nucleotide sequence identity with TbCSV-Y35 DNA1. Infectivity tests showed that TbCSV-Y132 DNA1 had no effect on the symptoms induced by TbCSV-Y35 or TbCSV-Y35 and Y35 DNAbeta in N. benthamiana plants, although Y132 DNA1 could replicate in these plants.


Subject(s)
Geminiviridae/genetics , Nanovirus/genetics , Nicotiana/virology , Blotting, Southern , Cloning, Molecular , DNA/metabolism , DNA, Viral , Genes, Plant , Plant Viruses , Time Factors , Nicotiana/metabolism
7.
J Cell Biol ; 164(4): 515-26, 2004 Feb 16.
Article in English | MEDLINE | ID: mdl-14970191

ABSTRACT

The promyelocytic leukemia (PML) protein is aggregated into nuclear bodies that are associated with diverse nuclear processes. Here, we report that the distance between a locus and its nearest PML body correlates with the transcriptional activity and gene density around the locus. Genes on the active X chromosome are more significantly associated with PML bodies than their silenced homologues on the inactive X chromosome. We also found that a histone-encoding gene cluster, which is transcribed only in S-phase, is more strongly associated with PML bodies in S-phase than in G0/G1 phase of the cell cycle. However, visualization of specific RNA transcripts for several genes showed that PML bodies were not themselves sites of transcription for these genes. Furthermore, knock-down of PML bodies by RNA interference did not preferentially change the expression of genes closely associated with PML bodies. We propose that PML bodies form in nuclear compartments of high transcriptional activity, but they do not directly regulate transcription of genes in these compartments.


Subject(s)
Intranuclear Inclusion Bodies/metabolism , Neoplasm Proteins/metabolism , Nuclear Proteins/metabolism , Transcription Factors/metabolism , Transcription, Genetic , ATP-Binding Cassette Transporters , Cell Cycle/physiology , Cell Nucleus/metabolism , Cells, Cultured , Chromosomes, Human, X , Collagen Type I/genetics , Collagen Type I, alpha 1 Chain , Female , Fibroblasts/cytology , Fibroblasts/metabolism , Gene Expression Regulation , Histocompatibility Antigens Class I/genetics , Humans , In Situ Hybridization, Fluorescence , Male , Multigene Family , Neoplasm Proteins/genetics , Nuclear Proteins/genetics , Promyelocytic Leukemia Protein , RNA, Small Interfering/genetics , RNA, Small Interfering/metabolism , Regression Analysis , Transcription Factors/genetics , Tumor Suppressor Proteins
SELECTION OF CITATIONS
SEARCH DETAIL
...