Summary The regeneration potential of mesenchymal stem cells (MSCs) diminishes with advanced age and this diminished potential is associated with changes in cellular functions. This study compared MSCs isolated from the bone marrow of rhesus monkeys (rBMSCs) in three age groups: young (< 5 years), middle (8–10 years), and old (> 12 years). The effects of aging on stem cell properties and indicators of stem cell fitness such as proliferation, differentiation, circadian rhythms, stress response proteins, miRNA expression, and global histone modifications in rBMSCs were analyzed. rBMSCs demonstrated decreased capacities for proliferation and differentiation as a function of age. The production of heat shock protein 70 (HSP70) and heat shock factor 1 (HSF1) were also reduced with increasing age. The level of a core circadian protein, Rev-erb α, was significantly increased in rBMSCs from old animals. Furthermore, analysis of miRNA expression profiles revealed an up-regulation of mir-766 and mir-558 and a down-regulation of mir-let-7f, mir-125b, mir-222, mir-199-3p, mir-23a, and mir-221 in old rBMSCs compare to young rBMSCs. However, there were no significant age-related changes in the global histone modification profiles of the four histone core proteins: H2A, H2B, H3, and H4 on rBMSCs. These changes represent novel insights into the aging process and could have implications regarding the potential for autologous stem cells therapy in older patients.

The first example of luminescent monosubstituted polyacetylenes (mono‐PAs) is presented, based on a contracted cis‐cisoid polyene backbone. It has an excellent circularly polarized luminescence (CPL) performance with a high dissymmetric factor (up to the order of 10−1). The luminescence stems from the helical cis‐cisoid PA backbone, which is tightly fixed by the strong intramolecular hydrogen bonds, thereby reversing the energy order of excited states and enabling an emissive energy dissipation. CPL switches are facilely achieved by the solvent and temperature through reversible conformational transition. By taking advantages of fast response and high sensitivity, the thin film of mono‐PAs could be used as a CPL‐based probe for quantitative detection of trifluoroacetic acid with a wider linear dynamic range than those of photoluminescence and circular dichroism. This work opens a new avenue to develop novel smart CPL materials through modulating conformational transition.

Two kinds of ZnO@polymer core-shell nanoparticles were prepared through polymerization initiated by the inherent free radicals on the ZnO surface. The as-prepared quantum dots exhibited intense blue fluorescence. They were used as raw materials to synthesize blue-emitting ZnO@polymer core-shell microspheres which were very stable, even in aqueous solutions of strong acids or alkalis. These microspheres, as stable aqueous suspensions, showed moderate quantum yields, and their self-assembly behavior and biomedical application could be expected. Recently, we polymerized MMA on specially pretreatedZnO nanocrystal surfaces at 60 uC with neither irradiation nor

Early steps of gene expression are a composite of promoter recognition, promoter activation, RNA synthesis and RNA processing, and it is known that SUMOylation, a post-translational modification, is involved in transcription regulation. We previously found that SUMO-1 marks chromatin at the proximal promoter regions of some of the most active housekeeping genes during interphase in human cells, but the SUMOylated targets on the chromatin remained unclear. In this study, we found that SUMO-1 marks the promoters of ribosomal protein genes via modification of the Scaffold Associated Factor B (SAFB) protein, and the SUMOylated SAFB stimulated both the binding of RNA polymerase to promoters and pre-mRNA splicing. Depletion of SAFB decreased RNA polymerase II binding to promoters and nuclear processing of the mRNA, though mRNA stability was not affected. This study reveals an unexpected role of SUMO-1 and SAFB in the stimulatory coupling of promoter binding, transcription initiation and RNA processing.