705 research outputs found

    PLoS. Biol.

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    Certain bacterial adhesins appear to promote a pathogen's extracellular lifestyle rather than its entry into host cells. However, little is known about the stimuli elicited upon such pathogen host-cell interactions. Here, we report that type IV pili (Tfp)-producing Neisseria gonorrhoeae (P(+)GC) induces an immediate recruitment of caveolin-1 (Cav1) in the host cell, which subsequently prevents bacterial internalization by triggering cytoskeletal rearrangements via downstream phosphotyrosine signaling. A broad and unbiased analysis of potential interaction partners for tyrosine-phosphorylated Cav1 revealed a direct interaction with the Rho-family guanine nucleotide exchange factor Vav2. Both Vav2 and its substrate, the small GTPase RhoA, were found to play a direct role in the Cav1-mediated prevention of bacterial uptake. Our findings, which have been extended to enteropathogenic Escherichia coli, highlight how Tfp-producing bacteria avoid host cell uptake. Further, our data establish a mechanistic link between Cav1 phosphorylation and pathogen-induced cytoskeleton reorganization and advance our understanding of caveolin function

    Protein Microarray On-Demand: A Novel Protein Microarray System

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    We describe a novel, simple and low-cost protein microarray strategy wherein the microarrays are generated by printing expression ready plasmid DNAs onto slides that can be converted into protein arrays on-demand. The printed expression plasmids serve dual purposes as they not only direct the synthesis of the protein of interest; they also serve to capture the newly synthesized proteins through a high affinity DNA-protein interaction. To accomplish this we have exploited the high-affinity binding (āˆ¼3ā€“7Ɨ10 āˆ’13 M) of E. coli Tus protein to Ter, a 20 bp DNA sequence involved in the regulation of E. coli DNA replication. In our system, each protein of interest is synthesized as a Tus fusion protein and each expression construct directing the protein synthesis contains embedded Ter DNA sequence. The embedded Ter sequence functions as a capture reagent for the newly synthesized Tus fusion protein. This ā€œall DNAā€ microarray can be converted to a protein microarray on-demand without need for any additional capture reagent.

    Repositioning of special schools within a specialist, personalised educational marketplace - the need for a representative principle

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    This paper considers how notions of inclusive education as defined in the United Nations Educational, Scientific and Cultural Organization (UNESCO) Salamanca Agreement (1994) have become dissipated, and can be developed and reframed to encourage their progress. It analyses the discourse within a range of academic, legal and media texts, exploring how this dissipation has taken place within the UK. Using data from 78 specialist school websites it contextualises this change in the use of the terms and ideas of inclusion with the rise of two other constructs, the 'specialist school' and 'personalisation'. It identifies the need for a precisely defined representative principle to theorise the type of school which inclusion aims to achieve, which cannot be subsumed by segregated providers. It suggests that this principle should not focus on the individual, but draw upon a liberal/democratic view of social justice, underlining inclusive education's role in removing social barriers that prevent equity, access and participation for all

    Ethical leadership in an age of evaluation: implications for wholeā€”school well-being

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    The evaluation and inspection of many public services, including education, has become increasingly common in most countries in the developed world (McNamara & Oā€™Hara, 2004; MacBeath & McGlynn, 2002). There are various reasons why this may be the case. It can be argued that it is, on the one hand, part of the movement towards low trust policies derived from the ideology of neo-liberalism which seeks to apply the values of the market to the public sector. On the other hand, it can be argued that increased evaluation is a necessary and defensible component of democratic accountability, responsibility and transparency (Oā€™Neill, 2002). The research reported here sets out to explore the idea of a personal vision or core of ethics as being central to educational leadership, through in-depth interviews with a number of school leaders. The chapter begins by briefly placing educational leadership in the modern context, characterised by the paradox of apparently greater decentralisation of responsibility to schools being in fact coupled with a further centralisation of actual power and greatly increased surveillance of performance (Neave, 1998). Relevant developments internationally, and then specifically in the context of Ireland, are described. It is suggested that in Ireland the modern educational context may indeed be creating difficult ethical and moral dilemmas for leaders to face. To see if this is so in practice, five in-depth interviews with school principals are reported. The evidence arising from these interviews indicates that school leaders do feel guided by a strong moral or ethical compass

    Discrete logic modelling as a means to link protein signalling networks with functional analysis of mammalian signal transduction

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    Large-scale protein signalling networks are useful for exploring complex biochemical pathways but do not reveal how pathways respond to specific stimuli. Such specificity is critical for understanding disease and designing drugs. Here we describe a computational approachā€”implemented in the free CNO softwareā€”for turning signalling networks into logical models and calibrating the models against experimental data. When a literature-derived network of 82 proteins covering the immediate-early responses of human cells to seven cytokines was modelled, we found that training against experimental data dramatically increased predictive power, despite the crudeness of Boolean approximations, while significantly reducing the number of interactions. Thus, many interactions in literature-derived networks do not appear to be functional in the liver cells from which we collected our data. At the same time, CNO identified several new interactions that improved the match of model to data. Although missing from the starting network, these interactions have literature support. Our approach, therefore, represents a means to generate predictive, cell-type-specific models of mammalian signalling from generic protein signalling networks

    The influence of distributed leadership on teachers' organizational commitment: a multilevel approach

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    In the present study the effects of a cooperative leadership team, distributed leadership, participative decision-making, and context variables on teachers' organizational commitment are investigated. Multilevel analyses on data from 1522 teachers indicated that 9% of the variance in teachers' organizational commitment is attributable to differences between schools. The analyses revealed that especially the presence of a cooperative leadership team and the amount of leadership support played a significantly positive key role in predicting teachers' organizational commitment. Also, participative decision-making and distribution of the supportive leadership function had a significant positive impact on teachers' organizational commitment. In contrast, distribution of the supervisory leadership function and teachers' job experience had a significant negative impact

    The relation between school leadership from a distributed perspective and teachers' organizational commitment: examining the source of the leadership function

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    Purpose: In this study the relationship between school leadership and teachersā€™ organizational commitment is examined by taking into account a distributed leadership perspective. The relation between teachersā€™ organizational commitment and contextual variables of teachersā€™ perceptions of the quality and the source of the supportive and supervisory leadership function, participative decision making, and cooperation within the leadership team are examined. Research Design: A survey was set up involving 1,522 teachers from 46 large secondary schools in Flanders (Belgium). Because the data in the present study have an inherent hierarchical structure, that is, teachers are nested into schools, hierarchical linear modeling techniques are applied. Findings: The analyses reveal that 9% of the variance in teachersā€™ organizational commitment is attributable to differences between schools. Teachersā€™ organizational commitment is mainly related to quality of the supportive leadership, cooperation within the leadership team, and participative decision making. Who performed the supportive leadership function plays only a marginally significant positive role. The quality of the supervisory leadership function and the role of the leadership team members in this function were not significantly related to teachersā€™ organizational commitment. Conclusions: The implications of the findings are that to promote teachersā€™ organizational commitment teachers should feel supported by their leadership team and that this leadership team should be characterized by group cohesion, role clarity, and goal orientedness. Recommendations for further research are provided

    From External Evaluation, to School Self-evaluation, to Peer Review

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    Most modern systems of school education around the world now have highly developed evaluation processes. Following quickly in the wake of external evaluation policies have followed calls for schools to develop their own capacities for self-review. An OECD report (2013) describes a number of ways in which developing school evaluation capacity should be a priority for school improvement. Among the reportā€™s suggestions are promoting peer learning among schools (pp. 469ā€“470). This chapter describes the research on external evaluation, internal evaluation and the relationship between these two. It then moves on to define and describes peer review and chart its growth. The accountability dimension of peer review is also explored. Finally the existing evidence on peer review is presented from the vocational and schools sectors to show key findings so far, and key conditions for effective peer review are described
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