Search

Arctium lappa, commonly called burdock, has a long medicinal and edible history. It has recently gained increasing attention because of its economic value. In this study, we obtained the complete chloroplast genome of A. lappa by Illumina Hiseq. The complete chloroplast genome of A. lappa is a typical circular structure with 152 708 bp in length. The GC content in the whole chloroplast genome of A. lappa is 37.7%. A total of 37 tRNA genes, 8 rRNA genes, and 87 protein-coding genes were successfully annotated. And the chloroplast genome contains 113 unique genes, 19 of which are duplicated in the inverted repeat. The distribution of 39 simple sequence repeats was analysed, and most of them are in the large single-copy (LSC) sequence. An inversion comprising 16 genes was found in the LSC region, which is 26 283 bp long. We performed multiple sequence alignments using 72 common protein-coding genes of 29 species and constructed a Maximum Parsimony (MP) tree. The MP phylogenetic result shows that A. lappa grouped together with Carthamus tinctorius, Centaurea diffusa, and Saussurea involucrata. The chloroplast genome of A. lappa is a valuable resource for further studies in Asteraceae. Key words: Arctium lappa, chloroplast genome, molecular structure, phylogenetic relationship. L'Arctium lappa, ou grande bardane, est connue depuis longtemps comme plante medicinale et comestible. Elle a recemment suscite une attention croissante en raison de sa valeur economique. Dans cette etude, les auteurs ont decode le genome chloroplastique complet de l'A lappa par sequencage Illumina Hiseq. Le genome chloroplastique complet de l A. lappa presente une structure circulaire typique comprenant 152 708 pb. Le contenu en GC est de 37,7 %. Au total, 37 genes d'ARNt, 8 genes d'ARNr et 87 genes codant pour des proteines ont ete annotes. Le genome chloroplastique compte 113 genes uniques, dont 19 sont dupliques au sein de la region inversee repetee. La distribution de 39 microsatellites a ete analysee et la plupart se trouvent au sein de la grande region a simple copie (LSC). Une inversion comprenant 16 genes et mesurant 26 283 pb a ete detectee au sein de la region LSC. Les auteurs ont realise des alignements multiples sur 72 genes communs codant pour des proteines chez 29 especes et produit un arbre phylogenetique par une approche de parcimonie maximale (MP). Le resultat de cette analyse phylogenetique a montre que l'A. lappa appartenait au meme groupe que le Carthamus tinctorius, le Centaurea diffusa et le Saussurea involucrata. Le genome chloroplastique de l'A. lappa constitue une ressource utile pour de futures etudes chez les Asteraceae. [Traduit par la Redaction] Mots-cles : Arctium lappa, genome chloroplastique, structure moleculaire, relation phylogenetique., Introduction Arctium lappa, a biennial herb of Asteraceae, is commonly known as a medicinal plant in many parts of the world, and it has been used as a therapeutic plant [...]

Yttria-stabilized zirconia (YSZ, Y2O3-ZrO2) ceramic with titanium dioxide nanoparticle (nanoTiO2) is prepared using conventional pressureless and two-step sintering (TSS) methods. The microstructure, phase composition, and mechanical properties of TSS-TiO2-ZrO2-Y2O3 nanocomposite ceramics are compared to those of the ceramics sintered using conventional sintering. The effect of TSS and nanoparticles on the sintering densification of the YSZ ceramics is investigated. X-ray diffractometry revealed that nanoTiO2 destabilizes c-ZrO2 and stabilizes t-ZrO2 in the YSZ. In addition, TSS is more conducive for grain refinement and sintering densification of the TiO2-ZrO2-Y2O3 nanocomposite ceramics; the average grain size of the samples decreased from 1.446 (conventional sintering) to 0.492 μm (TSS). Meanwhile, the relative density and sintering shrinkage of the TSS-1450 sample reached the maximum (98.23% and 22.92%, respectively) at a nanoTiO2 fraction of 7 wt%. The maximum microhardness and bending strength of the TSS-1450 ceramic matrix with 7-wt% nanoTiO2 were 1823 HV and 505 MPa, respectively. The nanoparticles distributed in the grain boundary induce the crack to the matrix, which induces the transgranular fracture, and nanoTiO2 improves the densification and mechanical properties of YSZ ceramics more than titanium dioxide microparticles. [ABSTRACT FROM AUTHOR]

Small-conductance [Ca.sup.2+]-activated [K.sup.+] channels (SK channels, [K.sub.Ca], channels) have been reported in excitable cells, where they aid in integrating changes in intracellular [Ca.sup.2+] with membrane potential. We recently reported for the first time the functional existence of SK2 ([K.sub.Ca]2.2) channels in human and mouse cardiac myocytes. Here, we report cloning of SK1 ([K.sub.Ca]2.1) and SK3 ([K.sub.Ca]2.3) channels from mouse atria and ventricles using RT-PCR. Full-length transcripts and their variants were detected for both SK1 and SK3 channels. Variants of mouse SK1 channel (mSK1) differ mainly in the COOH-terminal structure, affecting a portion of the sixth transmembrane segment (S6) and the calmodulin binding domain (CaMBD). Mouse SK3 channel (mSK3) differs not only in the number of polyglutamine repeats in the N[H.sub.2] terminus but also in the intervening sequences between the polyglutamine repeats. Full-length cardiac mSK1 and mSK3 show 99 and 91% nucleotide identity with those of mouse colon SK1 and SK3, respectively. Quantification of SK1, SK2, and SK3 transcripts between atria and ventricles was performed using real-time quantitative RT-PCR from single, isolated cardiomyocytes. SKI transcript was found to be more abundant in atria compared with ventricles, similar to the previously reported finding for SK2 channel. In contrast, SK3 showed similar levels of expression in atria and ventricles. Together, our data are the first to indicate the presence of the three different isoforms of SK channels in heart and the differential expression of SK1 and SK2 in mouse atria and ventricles. Because of the marked differential expression of SK channel isoforms in heart, specific ligands for [Ca.sup.2+]-activated [K.sup.+] currents may offer a unique therapeutic opportunity to modify atrial cells without interfering with ventricular myocytes. calcium-activated potassium current; mouse cardiac myocyte

Titanium alloy is an important metal material with excellent specific strength, which is widely used in aerospace field, nuclear industry, chemical medicine, and military industry. In order to investigate the connection conditions of TC4 titanium alloy and 316L stainless steel at different temperatures, the braze welding measurement with Ti57Zr13Cu21Ni9 filler metal was conducted in vacuum. The microstructure, morphology and phase of the joint were characterized by SEM (scanning electron microscope), EDS (Energy Dispersive Spectrometer) and XRD (X-ray diffraction), respectively. Microhardness and shear strength of the joint at room temperature and the bonding mechanism of TC4 and 316L were also investigated. The obtained results revealed that the main phases in the diffusion layer were Ti-based solid solution and Ti-Fe (TiFe and TiFe2) intermetallic compoundsands (IMCs) the center of the braze was mainly composed of Ti-Fe IMCs, (Ti, Zr)2(Ni, Cu), Ti-based solid solution. Additionally, the increase of brazing temperature firstly increased and then decreased the average shear strength with the maximum value of 133.9 MPa at 960 °C. [ABSTRACT FROM AUTHOR]

Vacuum brazing of TC4 titanium alloy and 316L stainless steel was conducted using Ag70.5Cu27.5Ti2 filler metal, the effects of microstructure and mechanical properties of brazing temperature on interface were investigated, and the bonding mechanism of brazed joint was also established. The results show that the filler metal and the base metal on both sides were completely diffused and bonded well. The microstructure of brazed joint interface is as follows: TC4 titanium alloy/diffusion layer(α-Ti + Ti2Cu)/reaction layer (including TiCu and Ti2Cu)/joint center area/TiFe layer/316L stainless steel. When the holding time lasted for 15 min, the shear strength of brazed joint first increased and then decreased as the brazing temperature rose. When the brazing temperature upped to 870 °C, the maximum of shear strength reached 190 MPa, and then the fracture occurred in the center of the brazed joint. The hardness of the joints gradually increased as the temperature rose, and the mean value reached maximum of 323 HV at 930 °C. [ABSTRACT FROM AUTHOR]

Abstract Background Cancers arise through an evolutionary process in which cell populations are subjected to selection; however, to date, the process of bladder cancer, which is one of the most common cancers in the world, remains unknown at a single-cell level. Results We carried out single-cell exome sequencing of 66 individual tumor cells from a muscle-invasive bladder transitional cell carcinoma (TCC). Analyses of the somatic mutant allele frequency spectrum and clonal structure revealed that the tumor cells were derived from a single ancestral cell, but that subsequent evolution occurred, leading to two distinct tumor cell subpopulations. By analyzing recurrently mutant genes in an additional cohort of 99 TCC tumors, we identified genes that might play roles in the maintenance of the ancestral clone and in the muscle-invasive capability of subclones of this bladder cancer, respectively. Conclusions This work provides a new approach of investigating the genetic details of bladder tumoral changes at the single-cell level and a new method for assessing bladder cancer evolution at a cell-population level.

Abstract Background Earlier studies have reported the production of histamine in colorectal cancers (CRCs). The effect of histamine is largely determined locally by the histamine receptor expression pattern. Recent evidence suggests that the expression level of histamine receptor H4 (HRH4) is abnormal in colorectal cancer tissues. However, the role of HRH4 in CRC progression and its clinical relevance is not well understood. The aim of this study is to evaluate the clinical and molecular phenotypes of colorectal tumors with abnormal HRH4 expression. Methods Immunoblotting, real-time PCR, immunofluorescence and immunohistochemistry assays were adopted to examine HRH4 expression in case-matched CRC samples (n = 107) and adjacent normal tissues (ANTs). To assess the functions of HRH4 in CRC cells, we established stable HRH4-transfected colorectal cells and examined cell proliferation, colony formation, cell cycle and apoptosis in these cells. Results The protein levels of HRH4 were reduced in most of the human CRC samples regardless of grade or Dukes classification. mRNA levels of HRH4 were also reduced in both early-stage and advanced CRC samples. In vitro studies showed that HRH4 over-expression caused growth arrest and induced expression of cell cycle proteins in CRC cells upon exposure to histamine through a cAMP -dependent pathway. Furthermore, HRH4 stimulation promoted the 5-Fu-induced cell apoptosis in HRH4-positive colorectal cells. Conclusion The results from the current study supported previous findings of HRH4 abnormalities in CRCs. Expression levels of HRH4 could influence the histamine-mediated growth regulation in CRC cells. These findings suggested a potential role of abnormal HRH4 expression in the progression of CRCs and provided some new clues for the application of HRH4-specific agonist or antagonist in the molecular therapy of CRCs.