127 research outputs found

    Effects of Elevated CO2 and N Addition on Growth and N2 Fixation of a Legume Subshrub (Caragana microphylla Lam.) in Temperate Grassland in China

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    It is well demonstrated that the responses of plants to elevated atmospheric CO2 concentration are species-specific and dependent on environmental conditions. We investigated the responses of a subshrub legume species, Caragana microphylla Lam., to elevated CO2 and nitrogen (N) addition using open-top chambers in a semiarid temperate grassland in northern China for three years. Measured variables include leaf photosynthetic rate, shoot biomass, root biomass, symbiotic nitrogenase activity, and leaf N content. Symbiotic nitrogenase activity was determined by the C2H2 reduction method. Elevated CO2 enhanced photosynthesis and shoot biomass by 83% and 25%, respectively, and the enhancement of shoot biomass was significant only at a high N concentration. In addition, the photosynthetic capacity of C. microphylla did not show down-regulation under elevated CO2. Elevated CO2 had no significant effect on root biomass, symbiotic nitrogenase activity and leaf N content. Under elevated CO2, N addition stimulated photosynthesis and shoot biomass. By contrast, N addition strongly inhibited symbiotic nitrogenase activity and slightly increased leaf N content of C. microphylla under both CO2 levels, and had no significant effect on root biomass. The effect of elevated CO2 and N addition on C. microphylla did not show interannual variation, except for the effect of N addition on leaf N content. These results indicate that shoot growth of C. microphylla is more sensitive to elevated CO2 than is root growth. The stimulation of shoot growth of C. microphylla under elevated CO2 or N addition is not associated with changes in N2-fixation. Additionally, elevated CO2 and N addition interacted to affect shoot growth of C. microphylla with a stimulatory effect occurring only under combination of these two factors

    The Ubiquitin Peptidase UCHL1 Induces G0/G1 Cell Cycle Arrest and Apoptosis Through Stabilizing p53 and Is Frequently Silenced in Breast Cancer

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    Background: Breast cancer (BrCa) is a complex disease driven by aberrant gene alterations and environmental factors. Recent studies reveal that abnormal epigenetic gene regulation also plays an important role in its pathogenesis. Ubiquitin carboxyl- terminal esterase L1 (UCHL1) is a tumor suppressor silenced by promoter methylation in multiple cancers, but its role and alterations in breast tumorigenesis remain unclear. Methodology/Principal Findings: We found that UCHL1 was frequently downregulated or silenced in breast cancer cell lines and tumor tissues, but readily expressed in normal breast tissues and mammary epithelial cells. Promoter methylation of UCHL1 was detected in 9 of 10 breast cancer cell lines (90%) and 53 of 66 (80%) primary tumors, but rarely in normal breast tissues, which was statistically correlated with advanced clinical stage and progesterone receptor status. Pharmacologic demethylation reactivated UCHL1 expression along with concomitant promoter demethylation. Ectopic expression of UCHL1 significantly suppressed the colony formation and proliferation of breast tumor cells, through inducing G0/G1 cell cycle arrest and apoptosis. Subcellular localization study showed that UCHL1 increased cytoplasmic abundance of p53. We further found that UCHL1 induced p53 accumulation and reduced MDM2 protein level, and subsequently upregulated the expression of p21, as well as cleavage of caspase3 and PARP, but not in catalytic mutant UCHL1 C90Sexpressed cells

    Pan-cancer analysis of whole genomes

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    Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

    Two luminescent 2D layered copper(I)-olefin coordination polymers with high thermal stability

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    The solvothermal reactions of 3-pyridylacrylic acid (3-HPYA) and 2-pyridylacrylic acid (2-HPYA) with Cu(CH 3CN) 4BF 4 yield two novel highly stable copper-(I)-olefin coordination polymers, [(3-PYA)Cu(I)]n (1) and {[(2-PYA)Cu(I)]·(H 2O)}n (2), respectively. Both polymers display 2D layered structures and yellow fluorescent emission in the solid state.link_to_subscribed_fulltex

    Total pancreatectomy compared with pancreaticoduodenectomy: a systematic review and meta-analysis

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    Du-Jiang Yang,1,* Jun-Jie Xiong,1,* Xue-Ting Liu,2 Jiao Li,3 Kanagarathna Mudiyanselage Dhanushka Layanthi Siriwardena,4 Wei-Ming Hu11Department of Pancreatic Surgery, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, People’s Republic of China; 2Department of Gastrointestinal Surgery, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, People’s Republic of China; 3Department of Emergency, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, People’s Republic of China; 4West China School of Medicine, Sichuan University, Chengdu 610041, Sichuan Province, People’s Republic of China *These authors contributed equally to this work  Aim: To assess whether total pancreatectomy (TP) is as feasible, safe, and efficacious as pancreaticoduodenectomy (PD).Materials and Methods: Major databases, including PubMed, EMBASE, Science Citation Index Expanded, Scopus and the Cochrane Library, were searched for studies comparing TP and PD between January 1943 and June 2018. The meta-analysis only included studies that were conducted after 2000. The primary outcomes were morbidity and mortality. Pooled odds ratios (ORs), weighted mean differences (WMDs) or hazard ratios (HRs) with 95 percent confidence intervals (CIs) were calculated using fixed effects or random effects models. The methodological quality of the included studies was evaluated by the Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool.Results: In total, 45 studies were included in this systematic review, and 5 non-randomized comparative studies with 786 patients (TP: 270, PD: 516) were included in the meta-analysis. There were no differences in terms of mortality (OR: 1.44, 95% CI: 0.66–3.16; P=0.36), hospital stay (WMD: −0.60, 95% CI: −1.78–0.59; P=0.32) and rates of reoperation (OR: 1.12; 95% CI: 0.55–2.31; P=0.75) between the two groups. In addition, morbidity was not significantly different between the two groups (OR: 1.41, 95% CI: 1.01–1.97; P=0.05); however, the results showed that the TP group tended to have more complications than the PD group. Furthermore, the operation time (WMD: 29.56, 95% CI: 8.23–50.89; P=0.007) was longer in the TP group. Blood loss (WMD: 339.96, 95% CI: 117.74–562.18; P=0.003) and blood transfusion (OR: 4.86, 95% CI: 1.93–12.29; P=0.0008) were more common in the TP group than in the PD group. There were no differences in the long-term survival rates between the two groups.Conclusion: This systematic review and meta-analysis suggested that TP may not be as feasible and safe as PD. However, TP and PD may have the same efficacy.Keywords: total pancreatectomy, pancreaticoduodenectomy, morbidity, mortality, meta-analysi
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