Self-assembling amphiphilic poly(propargyl methacrylate) grafted DNA copolymers into multi-strand helices.

DNA was covalently grafted onto poly(propargyl methacrylate) (PPMA) via "click" chemistry to synthesize the amphiphilic polymer brush. The PPMA-g-DNA brush could assemble into a primary structure of a nanofiber, which can be compactly spun into a multiple-strand helix in micron-length. The brush could also self-assemble with DNA labelled gold nanoparticles.

Diagnostic and prognostic significance of serum miR-145-5p expression in glioblastoma.

MicroRNA-145-5p downregulation has been shown to play important roles in the oncogenesis and progression of many cancer types including glioblastoma (GBM). However, the potential role of serum miR-145-5p in the diagnosis and prognosis of glioblastoma (GBM) remains poorly known. This study was designed to explore the clinical significance of serum miR-145-5p in patients with GBM. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was carried out to measure the serum levels of miR-145-5p in 117 GBM patients, 52 grade I/II glioma patients and 50 healthy volunteers. The associations between serum miR-145-5p level and the clinical variables as well as prognosis were analyzed. The bioinformatic analysis of the downstream targets of miR-145-5p was also performed. Compared to grade I/II glioma patients and healthy controls, serum miR-145-5p levels were significantly decreased in GBM patients. In addition, the receiver operating characteristic (ROC) analysis demonstrated that serum miR-145-5p might be a reliable diagnostic marker of GBM with an AUC of 0.895, combing with 84.6% sensitivity and 78.0% specificity. Low serum miR-145-5p level had significant correlation with aggressive clinicopathological parameters. Moreover, the Kaplan-Meier curve revealed that patients in the high serum miR-145-5p group survived significantly longer than those in the low serum miR-145-5p group. Multivariate analysis confirmed that serum miR-145-5p expression was an independent prognostic indicator for overall survival. The bioinformatic analysis revealed that many downstream genes and pathways that miR-145-5p regulated were closely associated with the initiation and development of cancer. Taken together, decreased serum miR-145-5p is a promising diagnostic and prognostic biomarker for GBM.

Detecting the oligomeric state of Escherichia coli MutS from its geometric architecture observed by an atomic force microscope at a single molecular level.

Atomic force microscopy (AFM), which provides true 3D surface topography, can also be used to determine the geometric parameters of proteins quantitatively at a single molecular level. In this paper, two different kinds of Escherichia coli MutS (MutS) protein were observed using AFM, and the geometric parameters of the proteins such as height, perimeter, area, and volume were measured. On the basis of these measurements, the molecular weight, association constant, oligomeric state, and orientation of MutS proteins on a mica surface were deduced. The oligomerization mechanism of MutS was analyzed in detail, and the results show that two different kinds of interactions between MutS protein may be involved in oligomerization. Our results also show that AFM imaging is an accurate method for analyzing the geometric structures of a single protein quantitatively at a single-molecule level.