54 research outputs found

    Deletion of the zinc transporter lipoprotein AdcAII causes hyperencapsulation of Streptococcus pneumoniae associated with distinct alleles of the Type I restriction modification system

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    The capsule is the dominant Streptococcus pneumoniae virulence factor, yet how variation in capsule thickness is regulated is poorly understood. Here, we describe an unexpected relationship between mutation of adcAII, which encodes a zinc uptake lipoprotein, and capsule thickness. Partial deletion of adcAII in three of five capsular serotypes frequently resulted in a mucoid phenotype that biochemical analysis and electron microscopy of the D39 adcAII mutants confirmed was caused by markedly increased capsule thickness. Compared to D39, the hyperencapsulated adcAII mutant strain was more resistant to complement-mediated neutrophil killing and was hypervirulent in mouse models of invasive infection. Transcriptome analysis of D39 and the adcAII mutant identified major differences in transcription of the Sp_0505-0508 locus, which encodes an SpnD39III (ST5556II) type I restrictionmodification system and allelic variation of which correlates with capsule thickness. A PCR assay demonstrated close linkage of the SpnD39IIIC and F alleles with the hyperencapsulated adcAII strains. However, transformation of adcAII with fixed SpnD39III alleles associated with normal capsule thickness did not revert the hyperencapsulated phenotype. Half of hyperencapsulated adcAII strains contained the same single nucleotide polymorphism in the capsule locus gene cps2E, which is required for the initiation of capsule synthesis. These results provide further evidence for the importance of the SpnD39III (ST5556II) type I restriction-modification system for modulating capsule thickness and identified an unexpected linkage between capsule thickness and mutation of adcAII. Further investigation will be needed to characterize how mutation of adcAII affects SpnD39III (ST5556II) allele dominance and results in the hyperencapsulated phenotype

    Concentration or representation : the struggle for popular sovereignty

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    There is a tension in the notion of popular sovereignty, and the notion of democracy associated with it, that is both older than our terms for these notions themselves and more fundamental than the apparently consensual way we tend to use them today. After a review of the competing conceptions of 'the people' that underlie two very different understandings of democracy, this article will defend what might be called a 'neo-Jacobin' commitment to popular sovereignty, understood as the formulation and imposition of a shared political will. A people's egalitarian capacity to concentrate both its collective intelligence and force, from this perspective, takes priority over concerns about how best to represent the full variety of positions and interests that differentiate and divide a community

    The visual and material dimensions of legitimacy:Accounting and the search for Socie-ties

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    We are grateful to the Fondation Audencia for the financial support provided for our archival research.The aim of this article is to contribute to the literature on legitimacy by investigating its material and visual dimensions. By drawing on studies on rhetoric as a means of composing visions of social order and on an historical analysis of accounts in three paradigmatic eras (Roman times, Renaissance and Modernity), it shows how symmetry in accounts constituted an aesthetic code which tied members of a community together in ‘socie-ties’. We investigate the rhetorical process of ratiocinatio and explore how the visual and material dimensions of accounts provided social actors with an opportunity to explore their positions and ties within a community. This process augmented social actors’ understanding of their current relations by reducing them to a series of entries into an account, thus allowing them to reflect on what it meant to be a legitimate member of a society.PostprintPeer reviewe

    Class dynamics of development: a methodological note

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    This article argues that class relations are constitutive of developmental processes and central to understanding inequality within and between countries. In doing so it illustrates and explains the diversity of the actually existing forms of class relations, and the ways in which they interplay with other social relations such as gender and ethnicity. This is part of a wider project to re- vitalise class analysis in the study of development problems and experiences
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