994 research outputs found
THE INFLUENCE OF THE CONSTRUCTION OF RED CULTURE IN UNIVERSITY LIBRARY ON COLLEGE STUDENTS’ READING ANXIETY
The Analysis of the Difficult Points on Developing E-Commerce of the Western Region in China
From 1999, China started to the project of “Development of Western Region of China” and many preferential policies were issued by the central government. However, after almost 5 years, compared with eastern region, the development of infrastructure is still relatively lower. As to the development of E-commerce, the most typical phenomenon is unbalance which means that the eastern region is much faster than the western because of territorial and economic factors. So it is necessary to get a whole picture and get a clear understanding of problems of current situation of E-commerce in west part of China in order to accelerate it. In this article, the difficult points of E-commerce development in west region are discussed, such as the law issue, infrastructure, information service providers and talents people and some strategies will be given finally based on the current situation of E-commerce in west part of China
Molecular Basis and Consequences of the Cytochrome c-tRNA Interaction.
The intrinsic apoptosis pathway occurs through the release of mitochondrial cytochrome c to the cytosol, where it promotes activation of the caspase family of proteases. The observation that tRNA binds to cytochrome c revealed a previously unexpected mode of apoptotic regulation. However, the molecular characteristics of this interaction, and its impact on each interaction partner, are not well understood. Using a novel fluorescence assay, we show here that cytochrome c binds to tRNA with an affinity comparable with other tRNA-protein binding interactions and with a molecular ratio of ∼3:1. Cytochrome c recognizes the tertiary structural features of tRNA, particularly in the core region. This binding is independent of the charging state of tRNA but is regulated by the redox state of cytochrome c. Compared with reduced cytochrome c, oxidized cytochrome c binds to tRNA with a weaker affinity, which correlates with its stronger pro-apoptotic activity. tRNA binding both facilitates cytochrome c reduction and inhibits the peroxidase activity of cytochrome c, which is involved in its release from mitochondria. Together, these findings provide new insights into the cytochrome c-tRNA interaction and apoptotic regulation
Doxorubicin resistance in breast cancer xenografts and cell lines can be counterweighted by microRNA-140-3p, through PD-L1 suppression
Background. Doxorubicin, a first-line chemotherapeutic drug for breast cancer, kills cancer cells by inducing DNA-crosslinking damage. Dysregulated micro-RNA (miRNA) is associated with the drug resistance of tumors. However, little is known about the effect of miRNA-140-3p on DOX resistance of breast cancer. Methods. The miRNA microarray was used to sequence the transcripts of DOX-chemoresistant breast cancer tissues and DOX-chemosensitive tissues. Then, the breast cancer tissue chip in the GEO database was also analyzed to screen the target gene. Flow cytometry, in situ hybridisation (ISH), immunohistochemistry (IHC), Western blot, cell proliferation assay, real-time PCR analyses (qRT-PCR), and pull-down assay were used to explore the effects of miRNA-140-3p and programmed death ligand-1 (PD-L1) on the chemoresistance of DOX-resistant breast cancer cells treated with DOX. In vivo, the DOX-resistant breast cancer cell lines treated with miRNA-140-3p overexpression were injected subcutaneously into mice to construct breast cancer subcutaneous xenograft tumor models. Results. Based on miRNA microarray, GEO database, and bioinformatics analysis, it was found that miRNA-140-3p and PD-L1 are the core molecules in the DOX resistance regulatory network in breast cancer, and lower miRNA-140-3p and higher PD-L1 expression levels were observed in DOX-resistant breast cancer tissues and cells. IHC results showed that compared with breast cancer tissues with high miRNA-140-3p expression, PD-L1 protein expression levels in breast cancer tissues with low miRNA-140-3p were significantly higher (P<0.01). Moreover, compared with DOX-sensitive tissues, the levels of PD-L1 protein expression in DOX-resistant tissues were significantly higher (P<0.01). In in vitro and in vivo experiments, the introduction of miRNA-140-3p decreased PD-L1 expression. Mechanically, we found that the MCF7/DOX and HS598T/DOX cells pretreated with miRNA140-3p inhibitor or exosomes containing PD-L1 have higher stemness and lower apoptosis rate, which can be abrogated by co-treating cells with anti-PD-L1 antibody or miRNA-140-3p mimic. Conclusions. MiRNA-140-3p can suppress PD-L1 expression in breast cancer cell-derived exosomes, thereby attenuating the chemoresistance induced by DOX in breast cancer
Soil bacterial community characteristics and influencing factors in different types of farmland shelterbelts in the Alaer reclamation area
To investigate the effects of various types of farmland shelterbelts on soil quality and soil bacterial community diversity, this study focused on soil samples from four different shelterbelt types in the Alaer reclamation area, including Populus euphratica Oliv.- Populus tomentosa Carrière (PP), Elaeagnus angustifolia L.- Populus euphratica Oliv. (EP), Populus alba var. pyramidalis Bunge (P), and Salix babylonica L. (S). We analyzed their physical, chemical, biological properties as well as the differences in bacterial community structure, and explored the influencing factors on soil microbial community characteristics through microbial correlation network analysis. The results showed that: (1) There were significant differences in soil properties among the four types of farmland shelterbelts (p < 0.05), with P soils exhibiting the highest levels of organic matter, total nitrogen, and total phosphorus contents. (2) The Alpha diversity indices of soil bacteria showed significant differences among the four types of farmland shelterbelts (p < 0.05), with the P soils displayed the highest Chao1 and Shannon indices. (3) There were differences in the composition and abundance of dominant soil bacterial communities among different farmland shelterbelts, notably, the abundances of Verrucomicrobia, Acidobacteria, and Planctomycetes were significantly higher in P soils compared to the other three types. (4) The complexity of the correlation network between microbial species and environmental factors was highest in EP soils, soil microbial biomass nitrogen and available phosphorus were the main influencing factors. These findings indicated that different types of farmland shelterbelts had significant impacts on soil properties and soil bacterial communities. Soil bacterial communities were regulated by soil properties, their changes reflected a combined effect of soil characteristics and tree species
Effects of different serum-free culture systems on the biological function of hUC-MSCs
Objective To evaluate the effects of three different serum-free culture systems on the biological function of human umbilical cord mesenchymal stem cells (hUC-MSC) cultured in vitro. Methods Three strains of umbilical cord tissues were obtained,divided into 3 experimental groups and cultured to the 3rd generation (P3) in three different serum-free culture systems (Group A: serum-free culture system synthesized by pure chemical components,group B: serum-free culture system consisting of platelet lysate+basic culture medium,group C: serum-free culture system consisting of fibrinogen coating+recombinant human protein). The cell proliferation,cell phenotype,three-line differentiation and immunomodulatory function were compared. Results All the cells in three groups were long and flat fusiform,adherent to the wall and uniform in size. The proliferation curve trend was similar,and the proliferation ability of P2 and P3 generations in groups A and B was better than that in group C (both P <0.05). The cells in three experimental groups all met the requirements of the International Stem Cell Society for identification of hUC-MSC cell surface markers. The expression levels of CD29 and CD90 in P3 generations in groups A and B were higher than those in group C (all P < 0.05),and all three experimental groups had the ability of three-line differentiation. Compared with the control group,the proliferation rate of T lymphocytes in P3 generation and the proportion of cytokines secreted by Th1 and Th17 cell subsets were significantly decreased in the three experimental groups,and the proportion of regulatory T cells (CD4+ CD25+ FOXP3+) was significantly increased in the three experimental groups,but there was no statistical significance among three experimental groups (all P > 0.05).Conclusions The hUC-MSC in three groups can maintain basic biological characteristics and immunomodulatory activity. The proliferation ability and expression levels of cell surface markers in groups A and B are superior to those in group C
MicroRNA-200c overexpression inhibits tumorigenicity and metastasis of CD117+CD44+ ovarian cancer stem cells by regulating epithelial-mesenchymal transition
BACKGROUND: Cancer stem cells (CSCs) are believed to be ‘seed cell’ in cancer recurrence and metastasis. MicroRNAs (miRNAs) can play an important role in the progression of primary tumor towards metastasis by regulating the epithelial-mesenchymal transition (EMT). The goal of this study was to investigate the effect of miRNA-200c overexpression on the EMT, tumorigenicity and metastasis of epithelial ovarian cancer (EOC) CSCs. METHODS: The EOC CD117(+)CD44(+)CSCs were isolated from the human ovarian cancer cell line SKOV3 by using a magnetic-activated cell sorting system, and the lentivirus miR-200c transduced CSCs were then selected for the study. The assays of colony forming, wound healing, cellular migration in vitro and tumor progression in vivo were performed. RESULTS: The miR-200c expression was reduced in the CD117(+)CD44(+)CSCs compared with the non-CD117(+)CD44(+)CSCs. However, the stable overexpression of the miR-200c in the CD117(+)CD44(+)CSCs resulted in a significant down-regulation of ZEB-1 and the Vimentin expression, an upregulation of the E-cadherin expression as well as a decrease of colony forming, migratory and invasion in vitro. Importantly, the miR-200c overexpression significantly inhibited the CD117(+)CD44(+)CSCs xenograft growth and lung metastasis in vivo in nude mice by inhibition of the EMT. In addition, the down-regulation of ZEB-1 showed the same efficacy as the miR-200c overexpression in the CD117(+)CD44(+)CSCs. CONCLUSION: These findings from this study suggest that the miR-200c overexpression may be considered a critical approach for the EOC CD117(+)CD44(+)CSCs in clinical trials
Chinese medicine PaBing-II protects human iPSC-derived dopaminergic neurons from oxidative stress
BackgroundPaBing-II Formula (PB-II) is a traditional Chinese medicine for treating Parkinson’s disease (PD). However, owing to the complexity of PB-II and the difficulty in obtaining human dopaminergic neurons (DAn), the mechanism of action of PB-II in PD treatment remains unclear. The aim of this study was to investigate the mechanisms underlying the therapeutic benefits of PB-II in patients with PD.MethodshiPSCs derived DAn were treated with H2O2 to construct the DAn oxidative damage model. SwissTargetPrediction was employed to predict the potential targets of the main compounds in serum after PB-II treatment. Metascape was used to analyze the pathways. Sprague-Dawley rats were used to construct the 6-hydroxydopamine (6-OHDA)-induced PD model, and the duration of administration was four weeks. RNA sequencing was used for Transcriptome analysis to find the signal pathways related to neuronal damage. The associated inflammatory factors were detected by enzyme-linked immunosorbent assay (ELISA). We identified PB-II as an Nrf2 activator using antioxidant-responsive element luciferase assay in MDA-MB-231 cells.ResultsIn vitro experiments showed that the treatment of PB-II-treated serum increased the percentage of TH+ cells, decreased inflammation and the apoptosis, reduced cellular reactive oxygen species, and upregulated the expression of Nrf2 and its downstream genes. Pathway analysis of the RNA-seq data of samples before and after the treatment with PB-II-treated serum identified neuron-associated pathways. In vivo experiments demonstrated that PB-II treatment of PD rat model could activate the Nrf2 signaling pathway, protect the midbrain DAn, and improve the symptoms in PD rats.ConclusionPB-II significantly protects DAn from inflammation and oxidative stress via Nrf2 pathway activation. These findings elucidate the roles of PB-II in PD treatment and demonstrate the application of hiPSC-derived DAn in research of Chinese medicine
- …