34 research outputs found

    Twitchy, the Drosophila orthologue of the ciliary gating protein FBF1/dyf-19, is required for coordinated locomotion and male fertility

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    Primary cilia are compartmentalised from the rest of the cell by a ciliary gate comprising transition fibres and a transition zone. The ciliary gate allows the selective import and export of molecules such as transmembrane receptors and transport proteins. These are required for the assembly of the cilium, its function as a sensory and signalling centre and to maintain its distinctive composition. Certain motile cilia can also form within the cytosol as exemplified by human and Drosophila sperm. The role of transition fibre proteins has not been well described in the cytoplasmic cilia. Drosophila have both compartmentalised primary cilia, in sensory neurons, and sperm flagella that form within the cytosol. Here, we describe phenotypes for twitchy the Drosophila orthologue of a transition fibre protein, mammalian FBF1/C. elegans dyf-19. Loss-of-function mutants in twitchy are adult lethal and display a severely uncoordinated phenotype. Twitchy flies are too uncoordinated to mate but RNAi-mediated loss of twitchy specifically within the male germline results in coordinated but infertile adults. Examination of sperm from twitchy RNAi-knockdown flies shows that the flagellar axoneme forms, elongates and is post-translationally modified by polyglycylation but the production of motile sperm is impaired. These results indicate that twitchy is required for the function of both sensory cilia that are compartmentalised from the rest of the cell and sperm flagella that are formed within the cytosol of the cell. Twitchy is therefore likely to function as part of a molecular gate in sensory neurons but may have a distinct function in sperm cells.ISSN:2046-639

    Amino acid availability acts as a metabolic rheostat to determine the magnitude of ILC2 responses

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    Group 2 innate lymphoid cells (ILC2) are functionally poised, tissue-resident lymphocytes that respond rapidly to damage and infection at mucosal barrier sites. ILC2 reside within complex microenvironments where they are subject to cues from both the diet and invading pathogens—including helminths. Emerging evidence suggests ILC2 are acutely sensitive not only to canonical activating signals but also perturbations in nutrient availability. In the context of helminth infection, we identify amino acid availability as a nutritional cue in regulating ILC2 responses. ILC2 are found to be uniquely preprimed to import amino acids via the large neutral amino acid transporters Slc7a5 and Slc7a8. Cell-intrinsic deletion of these transporters individually impaired ILC2 expansion, while concurrent loss of both transporters markedly impaired the proliferative and cytokine-producing capacity of ILC2. Mechanistically, amino acid uptake determined the magnitude of ILC2 responses in part via tuning of mTOR. These findings implicate essential amino acids as a metabolic requisite for optimal ILC2 responses within mucosal barrier tissues

    First-year Results of Broadband Spectroscopy of the Brightest Fermi-GBM Gamma-Ray Bursts

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    We present here our results of the temporal and spectral analysis of a sample of 52 bright and hard gamma-ray bursts (GRBs) observed with the Fermi Gamma-ray Burst Monitor (GBM) during its first year of operation (July 2008-July 2009). Our sample was selected from a total of 253 GBM GRBs based on each event peak count rate measured between 0.2 and 40MeV. The final sample comprised 34 long and 18 short GRBs. These numbers show that the GBM sample contains a much larger fraction of short GRBs, than the CGRO/BATSE data set, which we explain as the result of our (different) selection criteria and the improved GBM trigger algorithms, which favor collection of short, bright GRBs over BATSE. A first by-product of our selection methodology is the determination of a detection threshold from the GBM data alone, above which GRBs most likely will be detected in the MeV/GeV range with the Large Area Telescope (LAT) onboard Fermi. This predictor will be very useful for future multiwavelength GRB follow ups with ground and space based observatories. Further we have estimated the burst durations up to 10MeV and for the first time expanded the duration-energy relationship in the GRB light curves to high energies. We confirm that GRB durations decline with energy as a power law with index approximately -0.4, as was found earlier with the BATSE data and we also notice evidence of a possible cutoff or break at higher energies. Finally, we performed time-integrated spectral analysis of all 52 bursts and compared their spectral parameters with those obtained with the larger data sample of the BATSE data. We find that the two parameter data sets are similar and confirm that short GRBs are in general harder than longer ones.Comment: 40 pages, 11 figures, 3 tables, Submitted to Ap

    The Fermi GBM Gamma-Ray Burst Spectral Catalog: Four Years Of Data

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    In this catalog we present the updated set of spectral analyses of GRBs detected by the Fermi Gamma-Ray Burst Monitor (GBM) during its first four years of operation. It contains two types of spectra, time-integrated spectral fits and spectral fits at the brightest time bin, from 943 triggered GRBs. Four different spectral models were fitted to the data, resulting in a compendium of more than 7500 spectra. The analysis was performed similarly, but not identically to Goldstein et al. 2012. All 487 GRBs from the first two years have been re-fitted using the same methodology as that of the 456 GRBs in years three and four. We describe, in detail, our procedure and criteria for the analysis, and present the results in the form of parameter distributions both for the observer-frame and rest-frame quantities. The data files containing the complete results are available from the High-Energy Astrophysics Science Archive Research Center (HEASARC).Comment: Accepted for publication in ApJ

    Group 2 innate lymphoid cells are detrimental to the control of infection with Francisella tularensis

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    Innate lymphoid cells (ILCs) are capable of rapid response to a wide variety of immune challenges, including various respiratory pathogens. Despite this, their role in the immune response against the lethal intracellular bacterium Francisella tularensis is not yet known. In this study, we demonstrate that infection of the airways with F. tularensis results in a significant reduction in lung type 2 ILCs (ILC2s) in mice. Conversely, the expansion of ILC2s via treatment with the cytokine IL-33, or by adoptive transfer of ILC2s, resulted in significantly enhanced bacterial burdens in the lung, liver, and spleen, suggesting that ILC2s may favor severe infection. Indeed, specific reduction of ILC2s in a transgenic mouse model results in a reduction in lung bacterial burden. Using an in vitro culture system, we show that IFN-γ from the live vaccine strain–infected lung reduces ILC2 numbers, suggesting that this cytokine in the lung environment is mechanistically important in reducing ILC2 numbers during infection. Finally, we show Ab-mediated blockade of IL-5, of which ILC2s are a major innate source, reduces bacterial burden postinfection, suggesting that IL-5 production by ILC2s may play a role in limiting protective immunity. Thus, overall, we highlight a negative role for ILC2s in the control of infection with F. tularensis. Our work therefore highlights the role of ILC2s in determining the severity of potentially fatal airway infections and raises the possibility of interventions targeting innate immunity during infection with F. tularensis to benefit the host

    MedlinePlus-based health information prescriptions: a comparison of email vs paper delivery

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    Background The internet can provide evidence-based patient education to overcome time constraints of busy ambulatory practices. Health information prescriptions (HIPs) can be effectively integrated into clinic workflow, but compliance to visit health information sites such as MedlinePlus is limited.Objective Compare the efficacy of paper (pHIP) and email (eHIP) links to deliver HIPs; evaluate patient satisfaction with the HIP process and MedlinePlus information; assess reasons for noncompliance to HIPs.Method Of 948 patients approached at two internal medicine clinics affiliated with an academic medical centre, 592 gave informed consent after meeting the inclusion criteria. In this randomised controlled trial, subjects were randomised to receive pHIP or eHIP for accessing an intermediate website that provided up to five MedlinePlus links for physician-selected HIP conditions. Patients accessing the intermediate website were surveyed by email to assess satisfaction with the health information. Survey non-responders were contacted by telephone to determine the reasons for no response.Results One hundred and eighty-one patients accessed the website, with significantly more ‘filling’ eHIP than pHIP (38% vs 23%; P < 0.001). Most (82%) survey respondents found the website information useful, with 77% favouring email for future HIPs delivery. Lack of time, forgot, lost instructions or changed mind were reasons given for not accessing the websites.Conclusions Delivery of MedlinePlus-based HIPs in clinic is more effective using email prescriptions than paper. Satisfaction with the HIP information was high, but overall response was low and deserves further investigation to improve compliance and related outcomes

    Early fibrinogen concentrate therapy for major haemorrhage in trauma (E-FIT 1): results from a UK multi-centre, randomised, double blind, placebo-controlled pilot trial.

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    BACKGROUND: There is increasing interest in the timely administration of concentrated sources of fibrinogen to patients with major traumatic bleeding. Following evaluation of early cryoprecipitate in the CRYOSTAT 1 trial, we explored the use of fibrinogen concentrate, which may have advantages of more rapid administration in acute haemorrhage. The aims of this pragmatic study were to assess the feasibility of fibrinogen concentrate administration within 45 minutes of hospital admission and to quantify efficacy in maintaining fibrinogen levels ≥ 2 g/L during active haemorrhage. METHODS: We conducted a blinded, randomised, placebo-controlled trial at five UK major trauma centres with adult trauma patients with active bleeding who required activation of the major haemorrhage protocol. Participants were randomised to standard major haemorrhage therapy plus 6 g of fibrinogen concentrate or placebo. RESULTS: Twenty-seven of 39 participants (69%; 95% CI, 52-83%) across both arms received the study intervention within 45 minutes of admission. There was some evidence of a difference in the proportion of participants with fibrinogen levels ≥ 2 g/L between arms (p = 0.10). Fibrinogen levels in the fibrinogen concentrate (FgC) arm rose by a mean of 0.9 g/L (SD, 0.5) compared with a reduction of 0.2 g/L (SD, 0.5) in the placebo arm and were significantly higher in the FgC arm (p < 0.0001) at 2 hours. Fibrinogen levels were not different at day 7. Transfusion use and thromboembolic events were similar between arms. All-cause mortality at 28 days was 35.5% (95% CI, 23.8-50.8%) overall, with no difference between arms. CONCLUSIONS: In this trial, early delivery of fibrinogen concentrate within 45 minutes of admission was not feasible. Although evidence points to a key role for fibrinogen in the treatment of major bleeding, researchers need to recognise the challenges of timely delivery in the emergency setting. Future studies must explore barriers to rapid fibrinogen therapy, focusing on methods to reduce time to randomisation, using 'off-the-shelf' fibrinogen therapies (such as extended shelf-life cryoprecipitate held in the emergency department or fibrinogen concentrates with very rapid reconstitution times) and limiting the need for coagulation test-based transfusion triggers. TRIAL REGISTRATION: ISRCTN67540073 . Registered on 5 August 2015

    Genetic linkage analysis in the age of whole-genome sequencing

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    For many years, linkage analysis was the primary tool used for the genetic mapping of Mendelian and complex traits with familial aggregation. Linkage analysis was largely supplanted by the wide adoption of genome-wide association studies (GWASs). However, with the recent increased use of whole-genome sequencing (WGS), linkage analysis is again emerging as an important and powerful analysis method for the identification of genes involved in disease aetiology, often in conjunction with WGS filtering approaches. Here, we review the principles of linkage analysis and provide practical guidelines for carrying out linkage studies using WGS data
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