147 research outputs found

    Trade, investment and tax cooperation: tax competition.

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    The world is facing a new round of international tax competition that may result in a ruinous race to the bottom, undermining the fiscal capacity of states to respond to global challenges and to implement the Agenda 2030. G20 leaders must take action to strengthen multilateral and cooperative approaches to taxation, curtail harmful tax competition and protect their own tax base as well as that of developing countries.Seventh Framework Programme (FP7)758671Grenzen van fiscale soevereinitei

    The bacterial stressosome:a modular system that has been adapted to control secondary messenger signaling

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    SummaryThe stressosome complex regulates downstream effectors in response to environmental signals. In Bacillus subtilis, it activates the alternative sigma factor σB, leading to the upregulation of the general stress regulon. Herein, we characterize a stressosome-regulated biochemical pathway in Moorella thermoacetica. We show that the presumed sensor, MtR, and the scaffold, MtS, form a pseudo-icosahedral structure like that observed in B. subtilis. The N-terminal domain of MtR is structurally homologous to B. subtilis RsbR, despite low sequence identity. The affinity of the switch kinase, MtT, for MtS decreases following MtS phosphorylation and not because of structural reorganization. Dephosphorylation of MtS by the PP2C type phosphatase MtX permits the switch kinase to rebind the stressosome to reset the response. We also show that MtT regulates cyclic di-GMP biosynthesis through inhibition of a GG(D/E)EF-type diguanylate cyclase, demonstrating that secondary messenger levels are regulated by the stressosome

    Blue and Red Light Modulates SigB-Dependent Gene Transcription, Swimming Motility and Invasiveness in Listeria monocytogenes

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    Background: In a number of gram-positive bacteria, including Listeria, the general stress response is regulated by the alternative sigma factor B (SigB). Common stressors which lead to the activation of SigB and the SigB-dependent regulon are high osmolarity, acid and several more. Recently is has been shown that also blue and red light activates SigB in Bacillus subtilis. Methodology/Principal Findings: By qRT-PCR we analyzed the transcriptional response of the pathogen L. monocytogenes to blue and red light in wild type bacteria and in isogenic deletion mutants for the putative blue-light receptor Lmo0799 and the stress sigma factor SigB. It was found that both blue (455 nm) and red (625 nm) light induced the transcription of sigB and SigB-dependent genes, this induction was completely abolished in the SigB mutant. The blue-light effect was largely dependent on Lmo0799, proving that this protein is a genuine blue-light receptor. The deletion of lmo0799 enhanced the red-light effect, the underlying mechanism as well as that of SigB activation by red light remains unknown. Blue light led to an increased transcription of the internalin A/B genes and of bacterial invasiveness for Caco-2 enterocytes. Exposure to blue light also strongly inhibited swimming motility of the bacteria in a Lmo0799- and SigB-dependent manner, red light had no effect there. Conclusions/Significance: Our data established that visible, in particular blue light is an important environmental signal with an impact on gene expression and physiology of the non-phototrophic bacterium L. monocytogenes. In natural environments these effects will result in sometimes random but potentially also cyclic fluctuations of gene activity, depending on the light conditions prevailing in the respective habitat

    A Novel Signaling Network Essential for Regulating Pseudomonas aeruginosa Biofilm Development

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    The important human pathogen Pseudomonas aeruginosa has been linked to numerous biofilm-related chronic infections. Here, we demonstrate that biofilm formation following the transition to the surface attached lifestyle is regulated by three previously undescribed two-component systems: BfiSR (PA4196-4197) harboring an RpoD-like domain, an OmpR-like BfmSR (PA4101-4102), and MifSR (PA5511-5512) belonging to the family of NtrC-like transcriptional regulators. These two-component systems become sequentially phosphorylated during biofilm formation. Inactivation of bfiS, bfmR, and mifR arrested biofilm formation at the transition to the irreversible attachment, maturation-1 and -2 stages, respectively, as indicated by analyses of biofilm architecture, and protein and phosphoprotein patterns. Moreover, discontinuation of bfiS, bfmR, and mifR expression in established biofilms resulted in the collapse of biofilms to an earlier developmental stage, indicating a requirement for these regulatory systems for the development and maintenance of normal biofilm architecture. Interestingly, inactivation did not affect planktonic growth, motility, polysaccharide production, or initial attachment. Further, we demonstrate the interdependency of this two-component systems network with GacS (PA0928), which was found to play a dual role in biofilm formation. This work describes a novel signal transduction network regulating committed biofilm developmental steps following attachment, in which phosphorelays and two sigma factor-dependent response regulators appear to be key components of the regulatory machinery that coordinates gene expression during P. aeruginosa biofilm development in response to environmental cues

    Semi-Autonomous Revenue Authorities in Sub-Saharan Africa: Silver Bullet or White Elephant

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    A major component of tax administration reform in sub-Saharan Africa for the last 30 years has been the creation of semi-autonomous revenue authorities (SARAs). The effects of their creation on revenue performance have been much debated, although there are only a few quantitative studies. The core argument of this paper is that existing research suggesting diverse and contradictory outcomes has not taken account of trends in revenue performance in the years before the establishment of SARAs. Allowing for this revenue history our analysis based on 46 countries over the period 1980-2015 provides no robust evidence that SARAs induce an increase in revenue performance. This does not imply that SARAs may not provide benefits for tax collection, but they do not demonstrably increase (or decrease) revenue collected
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