4,768 research outputs found

    Segregation of a microsporidian parasite during host cell mitosis

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    We investigated the segregation of an intracellular microsporidian parasite during host cell division. A time-course experiment was carried out to examine the distribution of parasites relative to host chromosomal DNA via light and electron microscopy. Fluorescent light microscopy and EM studies showed that the parasite lay in the perinuclear zone of the host cell during interphase and segregated to daughter cells at mitosis. At metaphase, the parasite was frequently closely associated with host microtubules and mitochondria. Electron-dense bridges were observed between the parasites and the host microtubules and also between host mitochondria and microtubules. The study suggests that both the parasite and the host cell organelles segregate in association with spindle microtubules

    Cellular distribution of a feminizing microsporidian parasite: a strategy for transovarial transmission

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    The cellular distribution of a vertically transmitted, feminizing microsporidian was followed in its host Gammarus duebeni. In adult females the parasite was restricted to gonadal tissue, in particular primary and secondary follicle cells. Spores were diplokaryotic with a thin spore wall and a short polar filament, characteristics typical of ‘early’ spores involved in autoinfection. The diplokaryotic life-cycle, absence of spore groupings and of a pansporoblast membrane typify the genus Nosema. However, the unusual globular polaroplast of the spore and restriction of this stage to host ovarian tissue have not previously been described in Nosema. Sporogony occurred only in follicle cells adjacent to developing oocytes and was in synchrony with the process of vitellogenesis. Oocytes were infected after formation of intracellular connections with follicle cells but harboured only vegetative stages of the parasite. Parasites were associated with the perinuclear cytoplasm and, in developing embryos, segregated to daughter cells along the axis of the spindle. In juvenile animals there was no evidence of pathology linked with feminization and the parasite was found at low density in cells under the cuticle. The parasite is highly adapted to transovarial transmission with an efficient mechanism of oocyte infection and no evidence of pathology

    ‘Conflict versus Congruence’: A qualitative study exploring the experience of gender dysphoria for adults with autism spectrum disorder

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    An emergent evidence base indicates a higher prevalence of autism exists amongst people attending gender identity clinics. This qualitative study explored adults’ with autism experiences of coming to understand and address their gender dysphoria (GD). Data were collected and analysed using Grounded Theory. Ten adults with autism and GD undertook semi-structured interviews. A tentative theoretical framework of common processes involved in understanding and addressing GD for individuals with autism was developed. The experience is captured in the core category—Conflict versus Congruence. A key finding was the impact of autism as a barrier but sometimes a protective factor in participants’ understanding and addressing GD. Participants appeared to achieve greater personal congruence and wellbeing upon transition. Nevertheless, conflicts remained as they navigated the social world with a continuing fear of hostility and sense of difference due to having two stigmatised identities

    Tandem mirror with axisymmetric central cell ion

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    Liquid rhizobial inoculants for lentil and field pea

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    Non-Peer ReviewedThe traditional peat legume inoculants are viewed by western Canadian farmers as being difficult to apply. Accordingly, more "user-friendly" inoculants are being developed to ensure more wide-spread inoculation of legumes. A liquid inoculant developed by LiphaTech was evaluated as a carrier for Rhizobium leguminosarum strains 99A1 for lentil and 128C56G for pea. These two strains survived at titres exceeding log 8.0 per mL for ten months at 5°C and there was no loss of viability during shipping and handling. The Prairie Agricultural Machine Institute (PAMI) determined that the liquid inoculant gave a very flowable and uniform coverage of the seeds when applied through a grain auger and various types of seeding equipment. Liquid inoculant for pea and lentil resulted in yields equal or better than those observed for the traditional peat-based inoculant

    Improved Quantitative Plant Proteomics via the Combination of Targeted and Untargeted Data Acquisition.

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    Quantitative proteomics strategies - which are playing important roles in the expanding field of plant molecular systems biology - are traditionally designated as either hypothesis driven or non-hypothesis driven. Many of these strategies aim to select individual peptide ions for tandem mass spectrometry (MS/MS), and to do this mixed hypothesis driven and non-hypothesis driven approaches are theoretically simple to implement. In-depth investigations into the efficacies of such approaches have, however, yet to be described. In this study, using combined samples of unlabeled and metabolically (15)N-labeled Arabidopsis thaliana proteins, we investigate the mixed use of targeted data acquisition (TDA) and data dependent acquisition (DDA) - referred to as TDA/DDA - to facilitate both hypothesis driven and non-hypothesis driven quantitative data collection in individual LC-MS/MS experiments. To investigate TDA/DDA for hypothesis driven data collection, 7 miRNA target proteins of differing size and abundance were targeted using inclusion lists comprised of 1558 m/z values, using 3 different TDA/DDA experimental designs. In samples in which targeted peptide ions were of particularly low abundance (i.e., predominantly only marginally above mass analyser detection limits), TDA/DDA produced statistically significant increases in the number of targeted peptides identified (230 ± 8 versus 80 ± 3 for DDA; p = 1.1 × 10(-3)) and quantified (35 ± 3 versus 21 ± 2 for DDA; p = 0.038) per experiment relative to the use of DDA only. These expected improvements in hypothesis driven data collection were observed alongside unexpected improvements in non-hypothesis driven data collection. Untargeted peptide ions with m/z values matching those in inclusion lists were repeatedly identified and quantified across technical replicate TDA/DDA experiments, resulting in significant increases in the percentages of proteins repeatedly quantified in TDA/DDA experiments only relative to DDA experiments only (33.0 ± 2.6% versus 8.0 ± 2.7%, respectively; p = 0.011). These results were observed together with uncompromised broad-scale MS/MS data collection in TDA/DDA experiments relative to DDA experiments. Using our observations we provide guidelines for TDA/DDA method design for quantitative plant proteomics studies, and suggest that TDA/DDA is a broadly underutilized proteomics data acquisition strategy

    On the Strong Coupling Limit of the Faddeev-Hopf Model

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    The variational calculus for the Faddeev-Hopf model on a general Riemannian domain, with general Kaehler target space, is studied in the strong coupling limit. In this limit, the model has key similarities with pure Yang-Mills theory, namely conformal invariance in dimension 4 and an infinite dimensional symmetry group. The first and second variation formulae are calculated and several examples of stable solutions are obtained. In particular, it is proved that all immersive solutions are stable. Topological lower energy bounds are found in dimensions 2 and 4. An explicit description of the spectral behaviour of the Hopf map S^3 -> S^2 is given, and a conjecture of Ward concerning the stability of this map in the full Faddeev-Hopf model is proved.Comment: 21 pages, 0 figure

    Discovering predictive variables when evolving cognitive models

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    A non-dominated sorting genetic algorithm is used to evolve models of learning from different theories for multiple tasks. Correlation analysis is performed to identify parameters which affect performance on specific tasks; these are the predictive variables. Mutation is biased so that changes to parameter values tend to preserve values within the population's current range. Experimental results show that optimal models are evolved, and also that uncovering predictive variables is beneficial in improving the rate of convergence

    Activity of commercial detergents against conidia and chlamydospores of fusarium oxysporum f. sp. vasinfectum

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    Current containment recommendations for limiting the spread of race 4 of Fusarium oxysporum f. sp. vasinfectum in California lack non-corrosive yet effective alternatives to bleach for sanitizing equipment used in farming operations. To find an equivalent to Farmcleanse, an Australian product recommended for disinfecting equipment contaminated with the Fusarium wilt pathogen, 26 cleansers and degreasers commercially available in the United States were tested for their ability to kill spores of race 4 of F. oxysporum f. sp. vasinfectum. All treatments were tested at 1:10 and 1:100 (v/v) aqueous dilutions against conidia and chlamydospores in suspension. All treatments were also tested against chlamydospores in soil at a 1:10 dilution. Treatments demonstrating strong anti-fungal activity against spore suspensions at a 1:100 dilution were tested against conidia and chlamydospores at increasing aqueous dilutions (up to 1:100,000). Six products (Clorox, Simple Green d Pro 3, Trewax Nature's Orange, Formula 409 Antibacterial All Purpose Cleaner, Formula 409 Orange Cleaner Degreaser, and Lysol Antibacterial Kitchen Cleaner Citrus Scent) were effective against conidia and chlamydospores at a 1:100 dilution. Two products (Simple Green d Pro 3, Trewax Nature's Orange) gave results similar to bleach at dilutions up to 1:1000 on both conidia and chlamydospores in suspension. Quaternary ammonium compounds were present in four of the six most effective products. None of the cleansers performed as well as bleach against chlamydospores in soil. These results reveal useful alternatives to bleach, but similarity in brand names of distinctly different products should benoted. The results also point to the importance of completely removing soil from equipment prior to spraying with anti-fungal cleansers. © The Cotton Foundation 2011

    Summary report on the geology of the proposed HS2 Route (3) in the Chesham and Amersham Constituency

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    This brief open-file report summarises the information available from the British Geological Survey (BGS), a component body of the Natural Environment Research Council (NERC), on the geology, hydrogeology and potential geological hazards of the proposed HS2 Route 3 within the Chesham and Amersham Constituency, and surrounding areas. The report summarises the geology and hydrogeology of the district and highlights geological and hydrogeological considerations that may need further investigation along the route. Further review and analysis of existing data and possible field investigation would be required to confirm details of the local geology. The report was requested by Mrs Cheryl Gillan MP following a meeting with Dr Martin Smith, Head of Geology & Landscapes programme, on Monday 16th May 2011 at the offices of the Secretary of State for Wales in Whitehall
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