216 research outputs found

    Beyond society's desire for a slowed‐down temporal experience: Toward a nomological network of individuals' need‐for deceleration

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    This study expands on past deceleration and slow consumption research by introducing and validating a measure of need-for-deceleration, an individual's motivational ability to engage in activities aimed at slowing down the perceived fast passage of time. Following initial scale development, two studies establish construct validity by placing need-for-deceleration into a nomological network. Results indicate that the measure correlated with, but was distinct from, variables involving negative affective states, such as state anxiety and neuroticism. Need-for-deceleration scores were not related to materialism, but negatively correlated with self-efficacy, life satisfaction, work-life balance, and conscientiousness. Correlations were positive with need-for-uniqueness, future time orientation, and susceptibility to normative influence. Need-for-deceleration was also associated with regulatory focus (positively with prevention, and negatively with promotion focus). To explore criterion validity, a third study establishes associations between need-for-deceleration and consumer lifestyle variables. Developing and validating the scale can help researching and managing products relating to the consumption of time, wellness, mindfulness, and simplicity

    Modulation of the NF-κB Pathway by Bordetella pertussis Filamentous Hemagglutinin

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    Background Filamentous hemagglutinin (FHA) is a cell-associated and secreted adhesin produced by Bordetella pertussis with pro-apoptotic and pro-inflammatory activity in host cells. Given the importance of the NF-κB transcription factor family in these host cell responses, we examined the effect of FHA on NF-κB activation in macrophages and bronchial epithelial cells, both of which are relevant cell types during natural infection. Methodology/Principal Findings Exposure to FHA of primary human monocytes and transformed U-937 macrophages, but not BEAS-2B epithelial cells, resulted in early activation of the NF-κB pathway, as manifested by the degradation of cytosolic IκBα, by NF-κB DNA binding, and by the subsequent secretion of NF-κB-regulated inflammatory cytokines. However, exposure of macrophages and human monocytes to FHA for two hours or more resulted in the accumulation of cytosolic IκBα, and the failure of TNF-α to activate NF-κB. Proteasome activity was attenuated following exposure of cells to FHA for 2 hours, as was the nuclear translocation of RelA in BEAS-2B cells. Conclusions These results reveal a complex temporal dynamic, and suggest that despite short term effects to the contrary, longer exposures of host cells to this secreted adhesin may block NF-κB activation, and perhaps lead to a compromised immune response to this bacterial pathogen

    The crystal structure of the TetR family transcriptional repressor SimR bound to DNA and the role of a flexible N-terminal extension in minor groove binding

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    SimR, a TetR-family transcriptional regulator (TFR), controls the export of simocyclinone, a potent DNA gyrase inhibitor made by Streptomyces antibioticus. Simocyclinone is exported by a specific efflux pump, SimX and the transcription of simX is repressed by SimR, which binds to two operators in the simR-simX intergenic region. The DNA-binding domain of SimR has a classical helix-turn-helix motif, but it also carries an arginine-rich N-terminal extension. Previous structural studies showed that the N-terminal extension is disordered in the absence of DNA. Here, we show that the N-terminal extension is sensitive to protease cleavage, but becomes protease resistant upon binding DNA. We demonstrate by deletion analysis that the extension contributes to DNA binding, and describe the crystal structure of SimR bound to its operator sequence, revealing that the N-terminal extension binds in the minor groove. In addition, SimR makes a number of sequence-specific contacts to the major groove via its helix-turn-helix motif. Bioinformatic analysis shows that an N-terminal extension rich in positively charged residues is a feature of the majority of TFRs. Comparison of the SimR–DNA and SimR–simocyclinone complexes reveals that the conformational changes associated with ligand-mediated derepression result primarily from rigid-body rotation of the subunits about the dimer interface

    The economics of debt clearing mechanisms

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    We examine the evolution of decentralized clearinghouse mechanisms from the 13th to the 18th century; in particular, we explore the clearing of non- or limitedtradable debts like bills of exchange. We construct a theoretical model of these clearinghouse mechanisms, similar to the models in the theoretical matching literature, and show that specific decentralized multilateral clearing algorithms known as rescontre, skontrieren or virement des parties used by merchants were efficient in specific historical contexts. We can explain both the evolutionary self-organizing emergence of late medieval and early modern fairs, and its robustness during the 17th and 18th century

    Immune Evasion by Yersinia enterocolitica: Differential Targeting of Dendritic Cell Subpopulations In Vivo

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    CD4+ T cells are essential for the control of Yersinia enterocolitica (Ye) infection in mice. Ye can inhibit dendritic cell (DC) antigen uptake and degradation, maturation and subsequently T-cell activation in vitro. Here we investigated the effects of Ye infection on splenic DCs and T-cell proliferation in an experimental mouse infection model. We found that OVA-specific CD4+ T cells had a reduced potential to proliferate when stimulated with OVA after infection with Ye compared to control mice. Additionally, proliferation of OVA-specific CD4+ T cells was markedly reduced when cultured with splenic CD8α+ DCs from Ye infected mice in the presence of OVA. In contrast, T-cell proliferation was not impaired in cultures with CD4+ or CD4−CD8α− DCs isolated from Ye infected mice. However, OVA uptake and degradation as well as cytokine production were impaired in CD8α+ DCs, but not in CD4+ and CD4−CD8α− DCs after Ye infection. Pathogenicity factors (Yops) from Ye were most frequently injected into CD8α+ DCs, resulting in less MHC class II and CD86 expression than on non-injected CD8α+ DCs. Three days post infection with Ye the number of splenic CD8α+ and CD4+ DCs was reduced by 50% and 90%, respectively. The decreased number of DC subsets, which was dependent on TLR4 and TRIF signaling, was the result of a faster proliferation and suppressed de novo DC generation. Together, we show that Ye infection negatively regulates the stimulatory capacity of some but not all splenic DC subpopulations in vivo. This leads to differential antigen uptake and degradation, cytokine production, cell loss, and cell death rates in various DC subpopulations. The data suggest that these effects might be caused directly by injection of Yops into DCs and indirectly by affecting the homeostasis of CD4+ and CD8α+ DCs. These events may contribute to reduced T-cell proliferation and immune evasion of Ye

    Analysis of Tp53 Codon 72 Polymorphisms, Tp53 Mutations, and HPV Infection in Cutaneous Squamous Cell Carcinomas

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    Non-melanoma skin cancers are one of the most common human malignancies accounting for 2-3% of tumors in the US and represent a significant health burden. Epidemiology studies have implicated Tp53 mutations triggered by UV exposure, and human papilloma virus (HPV) infection to be significant causes of non-melanoma skin cancer. However, the relationship between Tp53 and cutaneous HPV infection is not well understood in skin cancers. In this study we assessed the association of HPV infection and Tp53 polymorphisms and mutations in lesional specimens with squamous cell carcinomas.We studied 55 cases of histologically confirmed cutaneous squamous cell carcinoma and 41 controls for the presence of HPV infection and Tp53 genotype (mutations and polymorphism).We found an increased number of Tp53 mutations in the squamous cell carcinoma samples compared with perilesional or control samples. There was increased frequency of homozygous Tp53-72R polymorphism in cases with squamous cell carcinomas, while the Tp53-72P allele (Tp53-72R/P and Tp53-72P/P) was more frequent in normal control samples. Carcinoma samples positive for HPV showed a decreased frequency of Tp53 mutations compared to those without HPV infection. In addition, carcinoma samples with a Tp53-72P allele showed an increased incidence of Tp53 mutations in comparison carcinomas samples homozygous for Tp53-72R.These studies suggest there are two separate pathways (HPV infection and Tp53 mutation) leading to cutaneous squamous cell carcinomas stratified by the Tp53 codon-72 polymorphism. The presence of a Tp53-72P allele is protective against cutaneous squamous cell carcinoma, and carcinoma specimens with Tp53-72P are more likely to have Tp53 mutations. In contrast Tp53-72R is a significant risk factor for cutaneous squamous cell carcinoma and is frequently associated with HPV infection instead of Tp53 mutations. Heterozygosity for Tp53-72R/P is protective against squamous cell carcinomas, possibly reflecting a requirement for both HPV infection and Tp53 mutations

    Genome engineering for improved recombinant protein expression in Escherichia coli

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    Stoichiometric gene-to-reaction associations enhance model-driven analysis performance: Metabolic response to chronic exposure to Aldrin in prostate cancer

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    [Background] Genome-scale metabolic models (GSMM) integrating transcriptomics have been widely used to study cancer metabolism. This integration is achieved through logical rules that describe the association between genes, proteins, and reactions (GPRs). However, current gene-to-reaction formulation lacks the stoichiometry describing the transcript copies necessary to generate an active catalytic unit, which limits our understanding of how genes modulate metabolism. The present work introduces a new state-of-the-art GPR formulation that considers the stoichiometry of the transcripts (S-GPR). As case of concept, this novel gene-to-reaction formulation was applied to investigate the metabolic effects of the chronic exposure to Aldrin, an endocrine disruptor, on DU145 prostate cancer cells. To this aim we integrated the transcriptomic data from Aldrin-exposed and non-exposed DU145 cells through S-GPR or GPR into a human GSMM by applying different constraint-based-methods.[Results] Our study revealed a significant improvement of metabolite consumption/production predictions when S-GPRs are implemented. Furthermore, our computational analysis unveiled important alterations in carnitine shuttle and prostaglandine biosynthesis in Aldrin-exposed DU145 cells that is supported by bibliographic evidences of enhanced malignant phenotype.[Conclusions] The method developed in this work enables a more accurate integration of gene expression data into model-driven methods. Thus, the presented approach is conceptually new and paves the way for more in-depth studies of aberrant cancer metabolism and other diseases with strong metabolic component with important environmental and clinical implications.The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007–2013) / ERC Grant Agreement n. 320737 and from the Novo Nordisk Foundation (NNF10CC1016517 and NNF14OC0009473). MC is funded by ICREA Academia programme-2015 (Icrea Fundation), AGAUR-Generalitat de Catalunya (2017SGR-1033), MINECO European Commission FEDER funds (SAF2017-89673-R) and Instituto de Salud Carlos III (CIBEREHD CB17/04/00023).Peer reviewe
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