Catalytic Chemiluminescence Polymer Dots for Ultrasensitive In Vivo Imaging of Intrinsic Reactive Oxygen Species in Mice

Chemiluminescence (CL) is a promising bioimaging method due to no interferences of light source and autofluorescence. However, compared to fluorescent emission, most CL reactions show short emission time and wavelength and weak emission intensity, which limit their applications in in vivo imaging. Here, we report mimic-enzyme catalytic CL polymer dots (hemin-Pdots) consisting of hemin and fluorescent conjugated polymer based on chemiluminescence resonance energy transfer. Hemin-Pdots show about 700× enhanced CL and over 10 h light emission in the presence of CL substrates and H₂O₂. These properties are mainly due to high-catalytic activity of hemin-Pdots and slow-diffusion-controlled heterogeneous reaction. Hemin-Pdots also possess excellent biocompatibility, good stability, emission wavelength redshift, and ultrasensitive response to reactive oxygen species (ROS), and they were successfully used for real-time imaging ROS levels in the peritoneal cavity and normal and tumor tissues of mice. Hemin-Pdots as new CL probes have wide applications in bioassays, bioimaging, and photodynamic therapy

Additional file 1 of A comparative study to determine the association of gut microbiome with schizophrenia in Zhejiang, China

Additional file 1: Figure S1. (A) Rarefaction curve analysis of archaeal 16S rRNA gene clone libraries. (B) Rank abundance curves of archaeal 16S rRNA gene clone libraries. Sample color codes are presented in the legend. Figure S2. Microbial composition and abundance at phylum level (A) and genus level (B) for gut microbiota in SZ (Case) and NC (Control) groups. The bars represent the average relative abundance of each genera, having significant differences between the two groups, with 95% confidence interval distribution and p value shown on their right

In Situ Monitoring of p53 Protein and MDM2 Protein Interaction in Single Living Cells Using Single-Molecule Fluorescence Spectroscopy

Protein–protein interactions play a central role in signal transduction, transcription regulations, enzymatic activity, and protein synthesis. The p53 protein is a key transcription factor, and its activity is precisely regulated by the p53–MDM2 interaction. Although the p53–MDM2 interaction has been studied, it is still not clear how p53 structures and external factors influence the p53–MDM2 interaction in living cells. Here, we developed a direct method for monitoring the p53–MDM2 interaction in single living cells using single-molecule fluorescence cross-correlation spectroscopy with a microfluidic chip. First, we labeled p53 and MDM2 proteins with enhanced green fluorescent protein (EGFP) and mCherry, respectively, using lentivirus infection. We then designed various mutants covering the three main domains of p53 (tetramerization, transactivation, and DNA-binding domains) and systematically studied effects of p53 protein primary, secondary, and quaternary structures on p53–MDM2 binding affinity in single living cells. We found that p53 dimers and tetramers can bind to MDM2, that the binding affinity of p53 tetramers is higher than that of p53 dimers, and that the affinity is closely correlated to the helicity of the p53 transactivation domain. The hot-spot mutation R175H in the DNA-binding domain reduced the binding of p53 to MDM2. Finally, we studied effects of inhibitors on p53–MDM2 interactions and dissociation dynamics of p53–MDM2 complexes in single living cells. We found that inhibitors Nutlin 3α and MI773 efficiently inhibited the p53–MDM2 interaction, but RITA did not work in living cells. This study provides a direct way for quantifying the relationship between protein structure and protein–protein interactions and evaluation of inhibitors in living cells