502 research outputs found

    The Porphyromonas gingivalis hemagglutinins HagB and HagC are major mediators of adhesion and biofilm formation

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    Porphyromonas gingivalis is a bacterium associated with chronic periodontitis that possesses a family of genes encoding hemagglutinins required for heme acquisition. In this study we generated ΔhagB and ΔhagC mutants in strain W83 and demonstrate that both hagB and hagC are required for adherence to oral epithelial cells. Unexpectedly, a double ΔhagB/ΔhagC mutant had less severe adherence defects than either of the single mutants, but was found to exhibit increased expression of the gingipain-encoding genes rgpA and kgp, suggesting that a ΔhagB/ΔhagC mutant is only viable in populations of cells that exhibit increased expression of genes involved in heme acquisition. Disruption of hagB in the fimbriated strain ATCC33277 demonstrated that HagB is also required for stable attachment of fimbriated bacteria to oral epithelial cells. Mutants of hagC were also found to form defective single and multi-species biofilms that had reduced biomass relative to biofilms formed by the wild-type strain. This study highlights the hitherto unappreciated importance of these genes in oral colonization and biofilm formation

    Parameter Estimation for Gravitational-wave Bursts with the BayesWave Pipeline

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    We provide a comprehensive multi-aspect study of the performance of a pipeline used by the LIGO-Virgo Collaboration for estimating parameters of gravitational-wave bursts. We add simulated signals with four different morphologies (sine-Gaussians (SGs), Gaussians, white-noise bursts, and binary black hole signals) to simulated noise samples representing noise of the two Advanced LIGO detectors during their first observing run. We recover them with the BayesWave (BW) pipeline to study its accuracy in sky localization, waveform reconstruction, and estimation of model-independent waveform parameters. BW localizes sources with a level of accuracy comparable for all four morphologies, with the median separation of actual and estimated sky locations ranging from 25 degrees. 1 to 30 degrees. 3. This is a reasonable accuracy in the two-detector case, and is comparable to accuracies of other localization methods studied previously. As BW reconstructs generic transient signals with SG wavelets, it is unsurprising that BW performs best in reconstructing SG and Gaussian waveforms. The BW accuracy in waveform reconstruction increases steeply with the network signal-to-noise ratio (S/N-net), reaching a 85% and 95% match between the reconstructed and actual waveform below S/N-net approximate to 20 and S/N-net approximate to 50, respectively, for all morphologies. The BW accuracy in estimating central moments of waveforms is only limited by statistical errors in the frequency domain, and is also affected by systematic errors in the time domain as BW cannot reconstruct low-amplitude parts of signals that are overwhelmed by noise. The figures of merit we introduce can be used in future characterizations of parameter estimation pipelines

    In Vitro Effect of Porphyromonas gingivalis Methionine Gamma Lyase on Biofilm Composition and Oral Inflammatory Response

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    Methanethiol (methyl mercaptan) is an important contributor to oral malodour and periodontal tissue destruction. Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum are key oral microbial species that produce methanethiol via methionine gamma lyase (mgl) activity. The aim of this study was to compare an mgl knockout strain of P. gingivalis with its wild type using a 10-species biofilm co-culture model with oral keratinocytes and its effect on biofilm composition and inflammatory cytokine production. A P. gingivalis mgl knockout strain was constructed using insertion mutagenesis from wild type W50 with gas chromatographic head space analysis confirming lack of methanethiol production. 10-species biofilms consisting of Streptococcus mitis, Streptococcus oralis, Streptococcus intermedius, Fusobacterium nucleatum ssp polymorphum, Fusobacterium nucleatum ssp vincentii, Veillonella dispar, Actinomyces naeslundii, Prevotella intermedia and Aggregatibacter actinomycetemcomitans with either the wild type or mutant P. gingivalis were grown on Thermanox cover slips and used to stimulate oral keratinocytes (OKF6-TERT2), under anaerobic conditions for 4 and 24 hours. Biofilms were analysed by quantitative PCR with SYBR Green for changes in microbial ecology. Keratinocyte culture supernatants were analysed using a multiplex bead immunoassay for cytokines. Significant population differences were observed between mutant and wild type biofilms; V. dispar proportions increased (p<0.001), whilst A. naeslundii (p<0.01) and Streptococcus spp. (p<0.05) decreased in mutant biofilms. Keratinocytes produced less IL-8, IL-6 and IL-1α when stimulated with the mutant biofilms compared to wild type. Lack of mgl in P. gingivalis has been shown to affect microbial ecology in vitro, giving rise to a markedly different biofilm composition, with a more pro-inflammatory cytokine response from the keratinocytes observed. A possible role for methanethiol in biofilm formation and cytokine response with subsequent effects on oral malodor and periodontitis is suggested

    Bayesian inference for compact binary coalescences with BILBY:Validation and application to the first LIGO-Virgo gravitational-wave transient catalogue

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    Gravitational waves provide a unique tool for observational astronomy. While the first LIGO–Virgo catalogue of gravitational-wave transients (GWTC-1) contains eleven signals from black hole and neutron star binaries, the number of observations is increasing rapidly as detector sensitivity improves. To extract information from the observed signals, it is imperative to have fast, flexible, and scalable inference techniques. In a previous paper, we introduced BILBY: a modular and user-friendly Bayesian inference library adapted to address the needs of gravitational-wave inference. In this work, we demonstrate that BILBY produces reliable results for simulated gravitational-wave signals from compact binary mergers, and verify that it accurately reproduces results reported for the eleven GWTC-1 signals. Additionally, we provide configuration and output files for all analyses to allow for easy reproduction, modification, and future use. This work establishes that BILBY is primed and ready to analyse the rapidly growing population of compact binary coalescence gravitational-wave signals

    Installing oncofertility programs for common cancers in optimum resource settings (Repro-Can-OPEN Study Part II): a committee opinion

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    The main objective of Repro-Can-OPEN Study Part 2 is to learn more about oncofertility practices in optimum resource settings to provide a roadmap to establish oncofertility best practice models. As an extrapolation for oncofertility best practice models in optimum resource settings, we surveyed 25 leading and well-resourced oncofertility centers and institutions from the USA, Europe, Australia, and Japan. The survey included questions on the availability and degree of utilization of fertility preservation options in case of childhood cancer, breast cancer, and blood cancer. All surveyed centers responded to all questions. Responses and their calculated oncofertility scores showed three major characteristics of oncofertility practice in optimum resource settings: (1) strong utilization of sperm freezing, egg freezing, embryo freezing, ovarian tissue freezing, gonadal shielding, and fractionation of chemo- and radiotherapy; (2) promising utilization of GnRH analogs, oophoropexy, testicular tissue freezing, and oocyte in vitro maturation (IVM); and (3) rare utilization of neoadjuvant cytoprotective pharmacotherapy, artificial ovary, in vitro spermatogenesis, and stem cell reproductive technology as they are still in preclinical or early clinical research settings. Proper technical and ethical concerns should be considered when offering advanced and experimental oncofertility options to patients. Our Repro-Can-OPEN Study Part 2 proposed installing specific oncofertility programs for common cancers in optimum resource settings as an extrapolation for best practice models. This will provide efficient oncofertility edification and modeling to oncofertility teams and related healthcare providers around the globe and help them offer the best care possible to their patients

    A View from the Past Into our Collective Future: The Oncofertility Consortium Vision Statement

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    Today, male and female adult and pediatric cancer patients, individuals transitioning between gender identities, and other individuals facing health extending but fertility limiting treatments can look forward to a fertile future. This is, in part, due to the work of members associated with the Oncofertility Consortium. The Oncofertility Consortium is an international, interdisciplinary initiative originally designed to explore the urgent unmet need associated with the reproductive future of cancer survivors. As the strategies for fertility management were invented, developed or applied, the individuals for who the program offered hope, similarly expanded. As a community of practice, Consortium participants share information in an open and rapid manner to addresses the complex health care and quality-of-life issues of cancer, transgender and other patients. To ensure that the organization remains contemporary to the needs of the community, the field designed a fully inclusive mechanism for strategic planning and here present the findings of this process. This interprofessional network of medical specialists, scientists, and scholars in the law, medical ethics, religious studies and other disciplines associated with human interventions, explore the relationships between health, disease, survivorship, treatment, gender and reproductive longevity. The goals are to continually integrate the best science in the service of the needs of patients and build a community of care that is ready for the challenges of the field in the future

    First measurement of the Hubble Constant from a Dark Standard Siren using the Dark Energy Survey Galaxies and the LIGO/Virgo Binary–Black-hole Merger GW170814

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    International audienceWe present a multi-messenger measurement of the Hubble constant H 0 using the binary–black-hole merger GW170814 as a standard siren, combined with a photometric redshift catalog from the Dark Energy Survey (DES). The luminosity distance is obtained from the gravitational wave signal detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO)/Virgo Collaboration (LVC) on 2017 August 14, and the redshift information is provided by the DES Year 3 data. Black hole mergers such as GW170814 are expected to lack bright electromagnetic emission to uniquely identify their host galaxies and build an object-by-object Hubble diagram. However, they are suitable for a statistical measurement, provided that a galaxy catalog of adequate depth and redshift completion is available. Here we present the first Hubble parameter measurement using a black hole merger. Our analysis results in , which is consistent with both SN Ia and cosmic microwave background measurements of the Hubble constant. The quoted 68% credible region comprises 60% of the uniform prior range [20, 140] km s−1 Mpc−1, and it depends on the assumed prior range. If we take a broader prior of [10, 220] km s−1 Mpc−1, we find (57% of the prior range). Although a weak constraint on the Hubble constant from a single event is expected using the dark siren method, a multifold increase in the LVC event rate is anticipated in the coming years and combinations of many sirens will lead to improved constraints on H 0

    Effects of Data Quality Vetoes on a Search for Compact Binary Coalescences in Advanced LIGO's First Observing Run

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    The first observing run of Advanced LIGO spanned 4 months, from September 12, 2015 to January 19, 2016, during which gravitational waves were directly detected from two binary black hole systems, namely GW150914 and GW151226. Confident detection of gravitational waves requires an understanding of instrumental transients and artifacts that can reduce the sensitivity of a search. Studies of the quality of the detector data yield insights into the cause of instrumental artifacts and data quality vetoes specific to a search are produced to mitigate the effects of problematic data. In this paper, the systematic removal of noisy data from analysis time is shown to improve the sensitivity of searches for compact binary coalescences. The output of the PyCBC pipeline, which is a python-based code package used to search for gravitational wave signals from compact binary coalescences, is used as a metric for improvement. GW150914 was a loud enough signal that removing noisy data did not improve its significance. However, the removal of data with excess noise decreased the false alarm rate of GW151226 by more than two orders of magnitude, from 1 in 770 years to less than 1 in 186000 years.Comment: 27 pages, 13 figures, published versio
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