175 research outputs found

    Drosophila Ovarian Stem Cell Establishment is Regulated by Nuclear Hormone Receptor ftz-f1

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    Stem cells are a fundamental underpinning of tissue biology. Loss of the self-renewing function of stem cells leads to conditions such as infertility and tissue wasting. Stem cells integrate a variety of signals to maintain their fate and proliferative capacity. Although intrinsic and local cues are well studied, less is known about how extrinsic signals, such as hormones, affect stem cell fate and function. The highly characterized Drosophila melanogaster steroid hormone ecdysone regulates germline stem cell (GSC) proliferation and self-renewal, as well as oogenesis and metamorphosis. Though many genes, including nuclear hormone receptor ftz transcription factor 1 (ftz-f1), are thought to be targets of ecdysone signaling, it is unclear how these targets impact GSC fate and function. To explore the role of ftz-f1 in ovarian stem cells, we used the UAS-GAL4 system and RNA interference (RNAi) to reduce ftz-f1 function specifically in germ cells or surrounding somatic cells. We demonstrate that ftz-f1 is intrinsically required for the establishment of the proper number of GSCs during development. Reduced ftz-f1 function in germ cells leads to a significant decrease in average number of GSCs. During larval stages, ftz-f1 depleted ovaries contain a number of PGCs located significantly further away from the terminal filament stacks. Our results also suggest that ftz-f1 is required in ovarian somatic cells during development for proper movement of germ cells out of the germarium in adult stages. Taken together, we suggest ftz-f1 function during juvenile stages is critical for the establishment of GSCs and development of their progeny

    Learning from our Multi-Stage Collaborative Autoethnography

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    This article is a reflection on eight, then seven, now five women’s collaborative efforts to explore the development of our own leader identities. While each of us conducts research on women and leadership, we are a diverse group of women: we were born in three different countries (United States, Paraguay, and New Zealand) and currently live in three different countries (United States, Canada, and New Zealand). We are of diverse races, sexual orientations, and generations; we have leadership experiences in a variety of disciplines and industries; and we vary in the priority we place on this study. In this paper, we review our experiences conducting research during the first three plus years of our collaborative autoethnographic study and share what we learned from those experiences. We address previously published considerations for developing collaborative autoethnographies including: the number of participants involved; the extent of involvement of the participants and the level of collaboration during the study; the collaborative approaches used in the study; and the approaches to writing. We add a reflection on our leadership practices throughout the study and on the confidentiality challenges that emerged. We also discuss how our division of the study into multiple life stages and multiple projects within the life stages has influenced our experiences and how the challenges resulting from the long duration of our study have influenced our productivity and are expected to influence our future plans. Our lessons learned should prove useful as other autoethnographic research groups begin their own research processes

    Business process modelling and visualisation to support e-government decision making: Business/IS alignment

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    © 2017 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/978-3-319-57487-5_4.Alignment between business and information systems plays a vital role in the formation of dependent relationships between different departments in a government organization and the process of alignment can be improved by developing an information system (IS) according to the stakeholders’ expectations. However, establishing strong alignment in the context of the eGovernment environment can be difficult. It is widely accepted that business processes in the government environment plays a pivotal role in capturing the details of IS requirements. This paper presents a method of business process modelling through UML which can help to visualise and capture the IS requirements for the system development. A series of UML models have been developed and discussed. A case study on patient visits to a healthcare clinic in the context of eGovernment has been used to validate the models

    C5 deficiency and C5a or C5aR blockade protects against cerebral malaria

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    Experimental infection of mice with Plasmodium berghei ANKA (PbA) provides a powerful model to define genetic determinants that regulate the development of cerebral malaria (CM). Based on the hypothesis that excessive activation of the complement system may confer susceptibility to CM, we investigated the role of C5/C5a in the development of CM. We show a spectrum of susceptibility to PbA in a panel of inbred mice; all CM-susceptible mice examined were found to be C5 sufficient, whereas all C5-deficient strains were resistant to CM. Transfer of the C5-defective allele from an A/J (CM resistant) onto a C57BL/6 (CM-susceptible) genetic background in a congenic strain conferred increased resistance to CM; conversely, transfer of the C5-sufficient allele from the C57BL/6 onto the A/J background recapitulated the CM-susceptible phenotype. The role of C5 was further explored in B10.D2 mice, which are identical for all loci other than C5. C5-deficient B10.D2 mice were protected from CM, whereas C5-sufficient B10.D2 mice were susceptible. Antibody blockade of C5a or C5a receptor (C5aR) rescued susceptible mice from CM. In vitro studies showed that C5a-potentiated cytokine secretion induced by the malaria product P. falciparum glycosylphosphatidylinositol and C5aR blockade abrogated these amplified responses. These data provide evidence implicating C5/C5a in the pathogenesis of CM

    Healthcare professionals’ views on patient-centered care in hospitals

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    Background: Patient-centered care (PCC) is a main determinant of care quality. Research has shown that PCC is a multi-dimensional concept, and organizations that provide PCC well report better patient and organizational outcomes. However, little is known about the relative importance of PCC dimensions. The aim of this study was therefore to investigate the relative importance of the eight dimensions of PCC according to hospital-based healthcare professionals, and examine whether their viewpoints are determined by context. Methods: Thirty-four healthcare professionals (16 from the geriatrics department, 15 from a surgical intensive care unit, 3 quality employees) working at a large teaching hospital in New York City were interviewed using Q methodology. Participants were asked to rank 35 statements representing eight dimensions of PCC extracted from the literature: patient preferences, physical comfort, coordination of care, emotional support, acce

    Identification of the Plasmodium berghei resistance locus 9 linked to survival on chromosome 9

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    Background: One of the main causes of mortality from severe malaria in Plasmodium falciparum infections is cerebral malaria (CM). An important host genetic component determines the susceptibility of an individual to develop CM or to clear the infection and become semi-immune. As such, the identification of genetic loci associated with susceptibility or resistance may serve to modulate disease severity. Methodology The Plasmodium berghei mouse model for experimental cerebral malaria (ECM) reproduces several disease symptoms seen in human CM, and two different phenotypes, a susceptible (FVB/NJ) and a resistant mouse strain (DBA/2J), were examined. Results: FVB/NJ mice died from infection within ten days, whereas DBA/2J mice showed a gender bias: males survived on average nineteen days and females either died early with signs of ECM or survived for up to three weeks. A comparison of brain pathology between FVB/NJ and DBA/2J showed no major differences with regard to brain haemorrhages or the number of parasites and CD3+ cells in the microvasculature. However, significant differences were found in the peripheral blood of infected mice: For example resistant DBA/2J mice had significantly higher numbers of circulating basophils than did FVB/NJ mice on day seven. Analysis of the F2 offspring from a cross of DBA/2J and FVB/NJ mice mapped the genetic locus of the underlying survival trait to chromosome 9 with a Lod score of 4.9. This locus overlaps with two previously identified resistance loci (char1 and pymr) from a blood stage malaria model. Conclusions: Survival best distinguishes malaria infections between FVB/NJ and DBA/2J mice. The importance of char1 and pymr on chromosome 9 in malaria resistance to P. berghei was confirmed. In addition there was an association of basophil numbers with survival

    Petri Net computational modelling of Langerhans cell Interferon Regulatory Factor Network predicts their role in T cell activation

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    Langerhans cells (LCs) are able to orchestrate adaptive immune responses in the skin by interpreting the microenvironmental context in which they encounter foreign substances, but the regulatory basis for this has not been established. Utilising systems immunology approaches combining in silico modelling of a reconstructed gene regulatory network (GRN) with in vitro validation of the predictions, we sought to determine the mechanisms of regulation of immune responses in human primary LCs. The key role of Interferon regulatory factors (IRFs) as controllers of the human Langerhans cell response to epidermal cytokines was revealed by whole transcriptome analysis. Applying Boolean logic we assembled a Petri net-based model of the IRF-GRN which provides molecular pathway predictions for the induction of different transcriptional programmes in LCs. In silico simulations performed after model parameterisation with transcription factor expression values predicted that human LC activation of antigen-specific CD8 T cells would be differentially regulated by epidermal cytokine induction of specific IRF-controlled pathways. This was confirmed by in vitro measurement of IFN-g production by activated T cells. As a proof of concept, this approach shows that stochastic modelling of a specific immune networks renders transcriptome data valuable for the prediction of functional outcomes of immune responses

    Genome Wide Analysis of Inbred Mouse Lines Identifies a Locus Containing Ppar-γ as Contributing to Enhanced Malaria Survival

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    The genetic background of a patient determines in part if a person develops a mild form of malaria and recovers, or develops a severe form and dies. We have used a mouse model to detect genes involved in the resistance or susceptibility to Plasmodium berghei malaria infection. To this end we first characterized 32 different mouse strains infected with P. berghei and identified survival as the best trait to discriminate between the strains. We found a locus on chromosome 6 by linking the survival phenotypes of the mouse strains to their genetic variations using genome wide analyses such as haplotype associated mapping and the efficient mixed-model for association. This new locus involved in malaria resistance contains only two genes and confirms the importance of Ppar-γ in malaria infection
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