A simple, rapid and ultrasensitive colorimetric detection of protein using aptamer-Au nanoparticles (AuNPs) conjugates based on a dot-blot array has been developed, which was combined with the unique optical properties of AuNPs, enabling the visual detection of protein within minutes without any instrument.
Dynamic assembly/disassembly of signaling complexes are crucial for cellular functions. Specialized latency and activation chaperones control the biogenesis of protein phosphatase 2A (PP2A) holoenzymes that contain a common scaffold and catalytic subunits and a variable regulatory subunit. Here we show that the butterfly-shaped TIPRL (TOR signaling pathway regulator) makes highly integrative multibranching contacts with the PP2A catalytic subunit, selective for the unmethylated tail and perturbing/inactivating the phosphatase active site. TIPRL also makes unusual wobble contacts with the scaffold subunit, allowing TIPRL, but not the overlapping regulatory subunits, to tolerate disease-associated PP2A mutations, resulting in reduced holoenzyme assembly and enhanced inactivation of mutant PP2A. Strikingly, TIPRL and the latency chaperone, α4, coordinate to disassemble active holoenzymes into latent PP2A, strictly controlled by methylation. Our study reveals a mechanism for methylation-responsive inactivation and holoenzyme disassembly, illustrating the complexity of regulation/signaling, dynamic complex disassembly, and disease mutations in cancer and intellectual disability.
A significant increase (ca. 22-fold) in the electricity generation due to a Shewanella oneidensis MR-1 biofilm was observed in the presence of Fe(3)O(4)/Au nanocomposites.
Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease, affecting approximately one-quarter of the global population, and has become a world public health issue. NAFLD is a clinicopathological syndrome characterized by hepatic steatosis, excluding ethanol and other definite liver damage factors. Recent studies have shown that the development of NAFLD is associated with lipid accumulation, oxidative stress, endoplasmic reticulum stress, and lipotoxicity. A range of natural products have been reported as regulators of NAFLD in vivo and in vitro. This paper reviews the pathogenesis of NAFLD and some natural products that have been shown to have therapeutic effects on NAFLD. Our work shows that natural products can be a potential therapeutic option for NAFLD.
Thymopentin (TP5) triggers an immune response by contacting with T cells; however the molecular basis of how TP5 achieves this process remains incompletely understood. According to the main idea of immunomodulation, we suppose that it would be necessary for TP5 to form complex with human class II major histocompatibility complex DR molecules (HLA-DR) before TP5 interacts with T cells. The uptake of TP5 by EBV-transformed B cells expressing HLA-DR molecules and the histogram of fluorescence intensities were observed by using fluorescent- labeled TP5, testifying the direct binding of TP5 to HLA-DR. The binding specificity was confirmed by the inhibition with unlabeled TP5, suggesting the recognition of TP5 by HLA-DR. To confirm the interaction between TP5 and HLA-DR, the complex formation was predicted by using various modeling strategies including six groups of trials with different parameters, alanine substitutions of TP5, and the mutants of HLA-DR. The results demonstrated that TP5 and its alanine substitutions assumed distinct conformations when they bound to HLA-DR. The observation further showed that there was flexibility in how the peptide bound within the binding cleft. Also, the molecular analysis supplemented a newly important discovery to the effect of Val anchor on TP5 binding HLA-DR, and revealed the important effects of Glu11 and Asn62 on the recognition of TP5. These results demonstrated the capability of TP5 to associate with HLA-DR in living antigen presenting cells (APC), thereby providing a new and promising strategy to understand the immunomodulation mechanism induced by TP5 and to design potential immunoregulatory polypeptides.
Background: Gallic acid (GA) is a plant phenol isolated from water caltrop which is reported to have anti-inflammatory and anti-cancer effects. In this study, the antiproliferative effect of GA on human pancreatic cancer cell lines CFPAC-1 and MiaPaCa-2 as well as hepatocytes HL-7702 as normal cells was examined. Particularly, the mechanism of GA-induced apoptosis in MiaPaCa-2 cells in vitro was further studied. Methods: Cell viability was measured using SRB assay, and apoptosis was detected by Hoechst staining and annexin V-PI staining assays. Mitochondrial membrane potential was detected by rhodamine-123 staining. Flow cytometry analysis was employed to detect the apoptosis-related events. Results: GA inhibited the proliferation of CFPAC-1 and MiaPaCa-2 cells in a time- and dose-dependent manner, with IC50S of 102.3 ± 2.4 and 135.2 ± 0.6 µM at 48 h, respectively. GA treatment led to the increased proportion of cell apoptosis from 12.5 ± 0.72 to 78.3 ± 2.48% at the concentrations of 6.25 and 25.0 µg/ml, which was evidenced again by chromatins staining assay. Also, GA activated caspase-3, caspase-9, and reactive oxygen species, elevated Bax expression and [Ca2+]i and reduced mitochondrial membrane potential (ΔΨm) in MiaPaCa-2 cells. Remarkably, when compared with human normal cells HL-7702 (IC50 >100 µg/ml), GA showed selective toxicity for cancer cells. Conclusions: GA can function as a cancer-selective agent by inducing apoptosis in MiaPaCa-2 cells via the mitochondria-mediated pathways. To the best of our knowledge, GA should open up new opportunities for the therapy of pancreatic cancer.
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