272 research outputs found

    Identifying invertebrate invasions using morphological and molecular analyses: North American Daphnia ‘pulex’ in New Zealand fresh waters

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    We used a DNA barcoding approach to identify specimens of the Daphnia pulex complex occurring in New Zealand lakes, documenting the establishment of non-indigenous North American Daphnia 'pulex'. Morphological delineation of species in this complex is problematic due to a lack of good morphological traits to distinguish the species, as there is a relatively high degree of morphological stasis within the group through evolutionary time. Accordingly, genetic analyses were used to determine the specific identity and likely geographic origin of this species. Morphologically, individuals most closely resembled Daphnia pulicaria or Daphnia pulex sensu lato, which cannot be separated morphologically. Furthermore, each of these taxa comprises separate species in North America and Europe, despite carrying the same names. We identified individuals using a 658 bp nucleotide portion of the mitochondrial cytochrome c oxidase subunit 1 gene (COI) as North American Daphnia 'pulex', being distinct from European Daphnia pulex sensu stricto and D. pulicaria from Europe or North America. Cellulose allozyme electrophoresis was used to confirm that individuals were not hybrids with D. pulicaria. North American Daphnia 'pulex' in New Zealand were first recorded in New Zealand from South Island lakes that are popular for overseas recreational fishers, indicating a possible source of introduction for this species (e.g. on/in fishing gear). Our study provides an additional example of how genetic techniques can be used for the accurate identification of non-indigenous taxa, particularly when morphological species determination is not possible. The growth of global databases such as GenBank and Barcode of Life Datasystems (BOLD) will further enhance this identification capacity

    Viral Interactions with Host RNA Decay Pathways

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    Eukaryotes have evolved a wide variety of RNA decay pathways to maintain cellular homeostasis, carry out programs of gene expression, and respond to changing environmental conditions. Individual RNA turnover mechanisms can operate constitutively or under only particular cellular conditions; similarly, some target many RNAs, while others act with great specificity. It has become increasingly clear that there are extensive interactions between viruses and the host RNA decay machinery. Often, the cellular RNA decay machinery poses a threat to viral gene expression, but viruses can also manipulate RNA decay pathways to promote viral replication. This special issue focuses on how cellular RNA decay factors recognize and degrade viral RNAs and viral strategies to subvert or evade these pathways

    Clinical characteristics of patients with heart failure and preserved left ventricular systolic function: a descriptive cohort study and comparison with heart failure and reduced systolic function

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    At the time of starting this work, the syndrome of heart failure with preserved systolic function was a neglected area in clinical cardiovascular research. The aim of this study was to improve our understanding of this condition by investigating the prevalence of HF-PSF in a cohort of patients admitted to hospital with heart failure, examining their clinical characteristics and determining their prognosis. By comparing the detailed clinical characteristics of patients with HF-PSF to those of patients with reduced systolic function, this study has provided a number of important insights into this common syndrome. Patients with preserved systolic function heart failure tend to be older, and are more likely to have a history of hypertension. These findings have now become well established in the HF-PSF literature. In relation to comorbidity, I specifically examined the prevalence of chronic obstructive pulmonary disease (COPD) in the subset of my study patients with HF-PSF, with a view to determining if they may have been misdiagnosed. On the contrary, while few patients had both a normal BNP and abnormal PFTs, a significant number of those patients with HF-PSF who had previously received a clinical diagnosis of COPD, actually had normal spirometry but an elevated BNP. This rather suggests that they may have been misdiagnosed with COPD, when in fact, they were suffering from HF-PSF. The importance of the interplay between COPD and HF is increasingly recognised, and these results serve to underline the need for further study in this area. In addition to the idea that HF-PSF was merely misdiagnosis, until recently conventional expectations were that HF-PSF would produce a mild version of the clinical syndrome. However, in this study I found that patients with HF-PSF did indeed display markers of severe and complicated heart failure. The majority were classified as Killip IIA or greater on admission to hospital, and the majority had moderate renal dysfunction. This suggestion that HF-PSF is not a benign condition is borne out by the mortality data from this study. All-cause mortality in the HF-PSF group, although lower than that for heart failure with reduced systolic function, was significant, with a case fatality rate of 37% after three years. This high mortality rate underscores the need for effective treatments for patients with HF-PSF

    Senescence as the main driver of iodide release from a diverse range of marine phytoplankton

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    The reaction between ozone and iodide at the sea surface is now known to be an important part of atmospheric ozone cycling, causing ozone deposition and the release of ozone-depleting reactive iodine to the atmosphere. The importance of this reaction is reflected by its inclusion in chemical transport models (CTMs). Such models depend on accurate sea surface iodide fields, but measurements are spatially and temporally limited. Hence, the ability to predict current and future sea surface iodide fields, i.e. sea surface iodide concentration on a narrow global grid, requires the development of process-based models. These models require a thorough understanding of the key processes that control sea surface iodide. The aim of this study was to explore if there are common features of iodate-to-iodide reduction amongst diverse marine phytoplankton in order to develop models that focus on sea surface iodine and iodine release to the troposphere. In order to achieve this, rates and patterns of changes in inorganic iodine speciation were determined in 10 phytoplankton cultures grown at ambient iodate concentrations. Where possible these data were analysed alongside results from previous studies. Iodate loss and some iodide production were observed in all cultures studied, confirming that this is a widespread feature amongst marine phytoplankton. We found no significant difference in log-phase, cell-normalised iodide production rates between key phytoplankton groups (diatoms, prymnesiophytes including coccolithophores and phaeocystales), suggesting that a phytoplankton functional type (PFT) approach would not be appropriate for building an ocean iodine cycling model. Iodate loss was greater than iodide formation in the majority of the cultures studied, indicating the presence of an as-yet-unidentified "missing iodine" fraction. Iodide yield at the end of the experiment was significantly greater in cultures that had reached a later senescence stage. This suggests that models should incorporate a lag between peak phytoplankton biomass and maximum iodide production and that cell mortality terms in biogeochemical models could be used to parameterise iodide production

    Does advance care planning in addition to usual care reduce hospitalisation for patients with advanced heart failure: A systematic review and narrative synthesis

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    BACKGROUND: People with advanced heart failure have repeated hospital admissions. Advance care planning can support patient preferences, but studies in people with heart failure have not been assessed.AIM: To evaluate the literature regarding advance care planning and hospitalisation in heart failure.DESIGN: Systematic review and narrative analysis.(PROSPEROCRD42017059190)DATA SOURCES: Electronic databases were searched (1990 to23.03.2017); MEDLINE(R), Cochrane Library, CINAHL, and Scopus. Four journals were hand searched. Two independent researchers screened against eligibility criteria. One reviewer extracted all data and a sample by a second. Quality was assessed by Cochrane Risk of Bias or the Critical Appraisal Skills Programme Tool for Cohort Studies.RESULTS: 8/1713 articles were included representing 14,357 participants from in/outpatient settings from five countries. Two randomised-controlled trials and one observational study assessed planning as part of a specialist palliative care intervention; one randomised-controlled trial assessed planning in addition to usual cardiology care; one randomised-controlled trial and one observational study assessed planning in an integrated cardiology-palliative care model; one observational study assessed evidence of planning (advance directive) as part of usual care, and one observational study was a secondary analysis of trial participants coded Do Not Attempt Cardiopulmonary Resuscitation. Advance care planning i) reduced hospitalisation(5/7 studies), ii) increased referral/use of palliative services (4/4 studies), iii) supported deaths in the patient-preferred place (2/2 studies).CONCLUSIONS:Advance care planning as part of a specialist palliative care careintervention reduces hospitalisation. Preliminary studies of planning integrated into generic care, accessing specialist palliative care support if needed, are promising

    Mental health workers’ attitudes toward individuals with a diagnosis of borderline personality disorder: a systematic literature review

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    The attitudes of mental health workers toward individuals with mental health conditions can impact the quality of care they provide. Negative attitudes among mental health workers seem particularly common in response to people diagnosed with borderline personality disorder (BPD). The current review aimed to identify and review the literature regarding mental health workers’ attitudes toward individuals diagnosed with BPD, specifically focusing on studies comparing workers’ attitudes toward BPD with attitudes toward other mental health diagnoses. The findings suggest that mental health workers have more negative attitudes toward individuals labeled as having BPD than toward individuals with other diagnoses, such as depression. This is likely due to factors associated with the label itself, in addition to workers’ perceptions of BPD symptoms and previous experiences of delivering treatment. The implications of these findings are considered, with a particular focus on how mental health services can effectively address negative attitudes toward BPD

    Palliative care needs in patients hospitalized with heart failure (PCHF) study: rationale and design

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    Abstract Aims The primary aim of this study is to provide data to inform the design of a randomized controlled clinical trial (RCT) of a palliative care (PC) intervention in heart failure (HF). We will identify an appropriate study population with a high prevalence of PC needs defined using quantifiable measures. We will also identify which components a specific and targeted PC intervention in HF should include and attempt to define the most relevant trial outcomes. Methods An unselected, prospective, near-consecutive, cohort of patients admitted to hospital with acute decompensated HF will be enrolled over a 2-year period. All potential participants will be screened using B-type natriuretic peptide and echocardiography, and all those enrolled will be extensively characterized in terms of their HF status, comorbidity, and PC needs. Quantitative assessment of PC needs will include evaluation of general and disease-specific quality of life, mood, symptom burden, caregiver burden, and end of life care. Inpatient assessments will be performed and after discharge outpatient assessments will be carried out every 4 months for up to 2.5 years. Participants will be followed up for a minimum of 1 year for hospital admissions, and place and cause of death. Methods for identifying patients with HF with PC needs will be evaluated, and estimates of healthcare utilisation performed. Conclusion By assessing the prevalence of these needs, describing how these needs change over time, and evaluating how best PC needs can be identified, we will provide the foundation for designing an RCT of a PC intervention in HF

    First detection of hard X-ray photons in the soft X-ray transient Narrow-Line Seyfert 1 galaxy WPVS 007: The X-ray photon distribution observed by Swift

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    We report on the first detection of hard X-ray photons (E>2.5 keV) in the X-ray transient Narrow-Line Seyfert 1 galaxy WPVS 007 which was the AGN with the softest X-ray spectrum during the ROSAT All-Sky Survey. The AGN is clearly detected at a level of about 2 x 10^{-17} W m^{-2} in the observed 0.3-10.0 keV band by Swift in a 50 ks observation in 2007 September. For the first time since the ROSAT All-Sky Survey observation in 1990 it was possible to derive an X-ray photon distribution by adding together all Swift observations that have been performed so far (85.5 ks in total). This photon distribution is consistent with an X-ray spectrum of an AGN with a partial covering absorber with a column density in the order of ~ 1 x 10^{23} cm^{-2} and a covering fraction of about 90%. A comparison with the 2002 Chandra data suggests that WPVS 007 has become brighter by a factor of about 4. The Swift data also suggest that the absorber which is causing the current low-state may have started to disappear. This disappearance is indicated by a significant change in the hardness ratio from a very soft X-ray state during the 2005 October to 2007 January observations to a rather hard X-ray state in the 2007 September observations. In the UV, WPVS 007 seems to become fainter by up to 0.5 mag over the last two years. The optical to X-ray spectral slope derived from the spectral energy distribution is alpha-ox=2.5 which classifies WPVS 007 as an X-ray weak AGN. After correcting for reddening and X-ray absorption, alpha-ox becomes 1.9 and the luminosity in the Big-Blue-Bump is log LBBB=37.7 [W], which translates into an Eddington ratio L/LEdd ~ 1.0.Comment: Accepted for publication in the Astronomical Journal, scheduled for December 2008, 8 pages, 3 figures, 3 table

    PRMT7 regulates RNA-binding capacity and protein stability in Leishmania parasites

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    RNA binding proteins (RBPs) are the primary gene regulators in kinetoplastids as transcriptional control is nearly absent, making Leishmania an exceptional model for investigating methylation of non-histone substrates. Arginine methylation is an evolutionarily conserved protein modification catalyzed by Protein aRginine Methyl Transferases (PRMTs). The chromatin modifier PRMT7 is the only Type III PRMT found in higher eukaryotes and a restricted number of unicellular eukaryotes. In Leishmania major, PRMT7 is a cytoplasmic protein implicit in pathogenesis with unknown substrates. Using comparative methyl-SILAC proteomics for the first time in protozoa, we identified 40 putative targets, including 17 RBPs hypomethylated upon PRMT7 knockout. PRMT7 can modify Alba3 and RBP16 trans-regulators (mammalian RPP25 and YBX2 homologs, respectively) as direct substrates in vitro. The absence of PRMT7 levels in vivo selectively reduces Alba3 mRNA-binding capacity to specific target transcripts and can impact the relative stability of RBP16 in the cytoplasm. RNA immunoprecipitation analyses demonstrate PRMT7-dependent methylation promotes Alba3 association with select target transcripts and thus indirectly stabilizes mRNA of a known virulence factor, δ-amastin surface antigen. These results highlight a novel role for PRMT7-mediated arginine methylation of RBP substrates, suggesting a regulatory pathway controlling gene expression and virulence in Leishmania. This work introduces Leishmania PRMTs as epigenetic regulators of mRNA metabolism with mechanistic insight into the functional manipulation of RBPs by methylation

    The Rpd3-complex regulates expression of multiple cell surface recycling factors in yeast

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    Intracellular trafficking pathways control residency and bioactivity of integral membrane proteins at the cell surface. Upon internalisation, surface cargo proteins can be delivered back to the plasma membrane via endosomal recycling pathways. Recycling is thought to be controlled at the metabolic and transcriptional level, but such mechanisms are not fully understood. In yeast, recycling of surface proteins can be triggered by cargo deubiquitination and a series of molecular factors have been implicated in this trafficking. In this study, we follow up on the observation that many subunits of the Rpd3 lysine deacetylase complex are required for recycling. We validate ten Rpd3-complex subunits in recycling using two distinct assays and developed tools to quantify both. Fluorescently labelled Rpd3 localises to the nucleus and complements recycling defects, which we hypothesised were mediated by modulated expression of Rpd3 target gene(s). Bioinformatics implicated 32 candidates that function downstream of Rpd3, which were over-expressed and assessed for capacity to suppress recycling defects of rpd3∆ cells. This effort yielded three hits: Sit4, Dit1 and Ldb7, which were validated with a lipid dye recycling assay. Additionally, the essential phosphatidylinositol-4-kinase Pik1 was shown to have a role in recycling. We propose recycling is governed by Rpd3 at the transcriptional level via multiple downstream target genes
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