Centromeric DNA characterization in the model grass Brachypodium distachyon provides insights on the evolution of the genus

Brachypodium distachyon is a well‐established model monocot plant, and its small and compact genome has been used as an accurate reference for the much larger and often polyploid genomes of cereals such as Avena sativa (oats), Hordeum vulgare (barley) and Triticum aestivum (wheat). Centromeres are indispensable functional units of chromosomes and they play a core role in genome polyploidization events during evolution. As the Brachypodium genus contains about 20 species that differ significantly in terms of their basic chromosome numbers, genome size, ploidy levels and life strategies, studying their centromeres may provide important insight into the structure and evolution of the genome in this interesting and important genus. In this study, we isolated the centromeric DNA of the B. distachyon reference line Bd21 and characterized its composition via the chromatin immunoprecipitation of the nucleosomes that contain the centromere‐specific histone CENH3. We revealed that the centromeres of Bd21 have the features of typical multicellular eukaryotic centromeres. Strikingly, these centromeres contain relatively few centromeric satellite DNAs; in particular, the centromere of chromosome 5 (Bd5) consists of only ~40 kb. Moreover, the centromeric retrotransposons in B. distachyon (CRBds) are evolutionarily young. These transposable elements are located both within and adjacent to the CENH3 binding domains, and have similar compositions. Moreover, based on the presence of CRBds in the centromeres, the species in this study can be grouped into two distinct lineages. This may provide new evidence regarding the phylogenetic relationships within the Brachypodium genus.     

Synthesis and antibacterial evaluation of novel 11-O-aralkylcarbamoyl-3-O-descladinosylclarithromycin derivatives

A series of novel 11-O-aralkylcarbamoyl-3-O-descladinosylclarithromycin derivatives were designed, synthesized and evaluated for their in vitro antibacterial activity. The results showed that the majority of the target compounds displayed potent activity against erythromycin-susceptible S. pyogenes, erythromycin-resistant S. pneumoniae A22072 expressing the mef gene and S. pneumoniae AB11 expressing the mef and erm genes. Besides, most of the target compounds exhibited moderate activity against erythromycin-susceptible S. aureus ATCC25923 and B. subtilis ATCC9372. In particular, compounds 11a, 11b, 11c, 11e, 11f and 11h were found to exert favorable antibacterial activity against erythromycin-susceptible S. pyogenes with the MIC values of 0.015–0.125?μg/mL. Furthermore, compounds 10e, 11a, 11b and 11c showed superior activity against erythromycin-resistant S. pneumoniae A22072 with the MIC values of 0.25–0.5?μg/mL. Additionally, compound 11c was the most effective against all the erythromycin-resistant S. pneumoniae strains (A22072, B1 and AB11), exhibiting 8-, 8- and 32-fold more potent activity than clarithromycin, respectively.     

The role of β‐adrenergic receptors and p38MAPK signaling pathways in physiological processes of cardiosphere‐derived cells

The effects of β adrenergic receptors (β‐ARs) and p38 mitogen‐activated protein kinases (MAPK) pathways on cardiosphere‐derived cells (CDCs) are largely unknown. This study aimed to investigate the roles of β‐ARs and p38MAPK pathways on the proliferation, apoptosis, and differentiation capacity of CDCs. The CDCs were treated with β1‐AR blocker (Met group), β2‐AR antagonist (ICI group), and p38MAPK inhibitor (SB group), non‐selective β‐AR blocker (PRO group), and β‐AR agonist (ISO group). The viability, apoptotic rate and differentiation status of CDCs were determined by MST‐1 assay, flow cytometery, and Western blot, respectively. The CDCs viability significantly reduced in ICI group (all P < 0.05), and SB group had a significant high viability after 48 h treatment (P < 0.05). Compared with control group, all treated groups had a low apoptotic rate. After treatment for 72 h, ISO treatment elevated the expression of Nkx2.5, and could partially or fully attenuate the inhibitory effects of β‐AR antagonists and/or p38MAPK inhibitor. A similar overall trend of protein expression levels among all groups could be observed between protein pairs of cTnT and β1‐AR as well as c‐Kit and β2‐AR, respectively. These results suggested that β‐ARs and p38MAPK signaling pathways play crucial roles in the proliferation and differentiation of CDCs. Our findings should be helpful for better understanding the molecular mechanism underlying the physiological processes of CDCs.     

A Network Meta‐Analysis of Short and Long‐Term Efficacy of Targeted Therapy With Single or Double‐Drug Regimens in the Treatment of Stage III/IV Malignant Melanoma Based on 16 Randomized Controlled Trials

For the treatment of stage III/IV malignant melanoma (MM), a network meta‐analysis (NMA) was conducted to compare the short and long‐term efficacy of targeted therapy with single or double‐drug regimens. All conducted randomized controlled trials (RCTs) searched from PubMed and Cochrane Library were included in the study for direct and indirect comparison for MM. The odds ratio (OR) and surface under the cumulative ranking curves (SUCRA) value of the targeted therapy with single or double‐drug regimens for treatment of stage III/IV MM were also analyzed. To group the treatments according to their similarity with regards to both outcomes, cluster analyses were performed. Ultimately, 16 RCTs were incorporated for this NMA. The NMA revealed that the overall response rate (ORR) values of single‐drug regimens (Vemurafenib [Vem], Dabrafenib [Dab], and Nivolumab [Niv]) were higher than those of Dacarbazine (Dac). Also the ORR values of double‐drug regimens (Dab + Trametinib [Dab + Tra], Niv + Ipilimumab [Niv + Ipi], and Vem + Cobimetinib [Vem + Cob]) were moderately higher than those of Dac. The results of the SUCRA showed that short‐term efficacy of single‐drug regimens (Vem and Dab) were better, while the short‐term efficacy of double‐drug regimens (Dab + Tra and Vem + Cob) were relatively better. It was determined that Vem, Dab, and Niv might be the best choice in evaluating the treatment of stage III/IV MM among different single‐drug targeted therapy regimens, while Dab + Tra, Niv + Ipi, and Vem + Cob might have better short‐term efficacy among different double‐drug targeted therapy regimens. J. Cell. Biochem. 119: 640–649, 2018. © 2017 Wiley Periodicals, Inc.