55 research outputs found

    A cardinal role for cathepsin D in co-ordinating the host-mediated apoptosis of macrophages and killing of pneumococci

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    The bactericidal function of macrophages against pneumococci is enhanced by their apoptotic demise, which is controlled by the anti-apoptotic protein Mcl-1. Here, we show that lysosomal membrane permeabilization (LMP) and cytosolic translocation of activated cathepsin D occur prior to activation of a mitochondrial pathway of macrophage apoptosis. Pharmacological inhibition or knockout of cathepsin D during pneumococcal infection blocked macrophage apoptosis. As a result of cathepsin D activation, Mcl-1 interacted with its ubiquitin ligase Mule and expression declined. Inhibition of cathepsin D had no effect on early bacterial killing but inhibited the late phase of apoptosis-associated killing of pneumococci in vitro. Mice bearing a cathepsin D-/- hematopoietic system demonstrated reduced macrophage apoptosis in vivo, with decreased clearance of pneumococci and enhanced recruitment of neutrophils to control pulmonary infection. These findings establish an unexpected role for a cathepsin D-mediated lysosomal pathway of apoptosis in pulmonary host defense and underscore the importance of apoptosis-associated microbial killing to macrophage function

    Potential effects of oilseed rape expressing oryzacystatin-1 (OC-1) and of purified insecticidal proteins on larvae of the solitary bee Osmia bicornis

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    Despite their importance as pollinators in crops and wild plants, solitary bees have not previously been included in non-target testing of insect-resistant transgenic crop plants. Larvae of many solitary bees feed almost exclusively on pollen and thus could be highly exposed to transgene products expressed in the pollen. The potential effects of pollen from oilseed rape expressing the cysteine protease inhibitor oryzacystatin-1 (OC-1) were investigated on larvae of the solitary bee Osmia bicornis (= O. rufa). Furthermore, recombinant OC-1 (rOC-1), the Bt toxin Cry1Ab and the snowdrop lectin Galanthus nivalis agglutinin (GNA) were evaluated for effects on the life history parameters of this important pollinator. Pollen provisions from transgenic OC-1 oilseed rape did not affect overall development. Similarly, high doses of rOC-1 and Cry1Ab as well as a low dose of GNA failed to cause any significant effects. However, a high dose of GNA (0.1%) in the larval diet resulted in significantly increased development time and reduced efficiency in conversion of pollen food into larval body weight. Our results suggest that OC-1 and Cry1Ab expressing transgenic crops would pose a negligible risk for O. bicornis larvae, whereas GNA expressing plants could cause detrimental effects, but only if bees were exposed to high levels of the protein. The described bioassay with bee brood is not only suitable for early tier non-target tests of transgenic plants, but also has broader applicability to other crop protection products

    Pediatric primary intramedullary spinal cord glioblastoma

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    Spinal cord tumors in pediatric patients are rare, representing less than 1% of all central nervous system tumors. Two cases of pediatric primary intramedullary spinal cord glioblastoma at ages 14 and 8 years are reported. Both patients presented with rapid onset paraparesis and quadraparesis. Magnetic resonance imaging in both showed heterogeneously enhancing solitary mass lesions localized to lower cervical and upper thoracic spinal cord parenchyma. Histopathologic diagnosis was glioblastoma. Case #1 had a small cell component (primitive neuroectodermal tumor-like areas), higher Ki67, and p53 labeling indices, and a relatively stable karyotype with only minimal single copy losses involving regions: Chr8;pter-30480019, Chr16;pter-29754532, Chr16;56160245–88668979, and Chr19;32848902-qter on retrospective comparative genomic hybridization using formalin-fixed, paraffin-embedded samples. Case #2 had relatively bland histomorphology and negligible p53 immunoreactivity. Both underwent multimodal therapy including gross total resection, postoperative radiation and chemotherapy. However, there was no significant improvement in neurological deficits, and overall survival in both cases was 14 months.This report highlights the broad histological spectrum and poor overall survival despite multi modality therapy. The finding of relatively unique genotypic abnormalities resembling pediatric embryonal tumors in one case may highlight the value of genome-wide profiling in development of effective therapy. The differences in management with intracranial and low-grade spinal cord gliomas and current management issues are discussed

    Pollen Competition as a Reproductive Isolation Barrier Represses Transgene Flow between Compatible and Co-Flowering Citrus Genotypes

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    Background/Objective: Despite potential benefits granted by genetically modified (GM) fruit trees, their release and commercialization raises concerns about their potential environmental impact, and the transfer via pollen of transgenes to cross-compatible cultivars is deemed to be the greatest source for environmental exposure. Information compiled from field trials on GM trees is essential to propose measures to minimize the transgene dispersal. We have conducted a field trial of seven consecutive years to investigate the maximum frequency of pollen-mediated crop-to-crop transgene flow in a citrus orchard, and its relation to the genetic, phenological and environmental factors involved. Methodology/Principal Findings: Three different citrus genotypes carrying the uidA (GUS) tracer marker gene (pollen donors) and a non-GM self-incompatible contiguous citrus genotype (recipient) were used in conditions allowing natural entomophilous pollination to occur. The examination of 603 to 2990 seeds per year showed unexpectedly low frequencies (0.17-2.86%) of transgene flow. Paternity analyses of the progeny of subsets of recipient plants using 10 microsatellite (SSR) loci demonstrated a higher mating competence of trees from another non-GM pollen source population that greatly limited the mating chance of the contiguous cross-compatible and flowering-synchronized transgenic pollen source. This mating superiority could be explained by a much higher pollen competition capacity of the non-GM genotypes, as was confirmed through mixed-hand pollinations. Conclusions/Significance: Pollen competition strongly contributed to transgene confinement. Based on this finding, suitable isolation measures are proposed for the first time to prevent transgene outflow between contiguous plantings of citrus types that may be extendible to other entomophilous transgenic fruit tree species. (Résumé d'auteur

    Climate simulations for 1880-2003 with GISS modelE

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    We carry out climate simulations for 1880-2003 with GISS modelE driven by ten measured or estimated climate forcings. An ensemble of climate model runs is carried out for each forcing acting individually and for all forcing mechanisms acting together. We compare side-by-side simulated climate change for each forcing, all forcings, observations, unforced variability among model ensemble members, and, if available, observed variability. Discrepancies between observations and simulations with all forcings are due to model deficiencies, inaccurate or incomplete forcings, and imperfect observations. Although there are notable discrepancies between model and observations, the fidelity is sufficient to encourage use of the model for simulations of future climate change. By using a fixed well-documented model and accurately defining the 1880-2003 forcings, we aim to provide a benchmark against which the effect of improvements in the model, climate forcings, and observations can be tested. Principal model deficiencies include unrealistically weak tropical El Nino-like variability and a poor distribution of sea ice, with too much sea ice in the Northern Hemisphere and too little in the Southern Hemisphere. The greatest uncertainties in the forcings are the temporal and spatial variations of anthropogenic aerosols and their indirect effects on clouds.Comment: 44 pages; 19 figures; Final text accepted by Climate Dynamic

    Alzheimer's Disease susceptibility genes APOE and TOMM40, and hippocampal volumes in the Lothian birth cohort 1936

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    The APOE Δ and TOMM40 rs10524523 (‘523’) variable length poly-T repeat gene loci have been significantly and independently associated with Alzheimer’s disease (AD) related phenotypes such as age of clinical onset. Hippocampal atrophy has been significantly associated with memory impairment, a characteristic of AD. The current study aimed to test for independent effects of APOE Δ and TOMM40 ‘523’ genotypes on hippocampal volumes as assessed by brain structural MRI in a relatively large sample of community-dwelling older adults. As part of a longitudinal study of cognitive ageing, participants in the Lothian Birth Cohort 1936 underwent genotyping for APOE Δ2/Δ3/Δ4 status and TOMM40 ‘523’ poly-T repeat length, and detailed structural brain MRI at a mean age of 72.7 years (standard deviation = 0.7, N range = 624 to 636). No significant effects of APOE Δ or TOMM40 523 genotype were found on hippocampal volumes when analysed raw, or when adjusted for either intracranial or total brain tissue volumes. In summary, in a large community-dwelling sample of older adults, we found no effects of APOE Δ or TOMM40 523 genotypes on hippocampal volumes. This is discrepant with some previous reports of significant association between APOE and left/right hippocampal volumes, and instead echoes other reports that found no association. Previous significant findings may partly reflect type 1 error. Future studies should carefully consider: 1) their specific techniques in adjusting for brain size; 2) assessing more detailed sub-divisions of the hippocampal formation; and 3) testing whether significant APOE-hippocampal associations are independent of generalised brain atrophy

    Methylphenidate use among students living in junior on-campus residences of the University of the Free State

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    Background: The use of methylphenidate as cognitive enhancer is a growing trend among students at tertiary institutions globally. This study aimed to determine the prevalence of methylphenidate use and co-use with alcohol among on-campus residence students of the University of the Free State (UFS). Methods: For this cross-sectional study, 10 junior residences were randomly selected and 1 761 anonymous questionnaires handed out for all students living in these residences during 2015. Data were collected on demographics, use of methylphenidate and co-use of methylphenidate with alcohol. Results: In total, 585 questionnaires (response rate 33.2%) were received and analysed. Sixty-six (11.3%) participants reported past-year use of methylphenidate. While only 18 (27.3%) of past-year users were diagnosed with ADHD, 44 (66.7%) obtained their supply through doctors’ prescriptions, 21 (31.8%) from friends without payment, and 4 (6.1%) bought it from illegal sources. Of the past-year users, 24.2% had used methylphenidate before consuming alcohol. Conclusion: Off-label prescribing, diversion of prescriptions and illegal trade in methylphenidate occur among students at the UFS. The frequent co-use of methylphenidate and alcohol may indicate a lack of information on the effects of the medication, rather than deliberate misuse. (Full text of the research articles are available online at www.medpharm.tandfonline.com/ojfp) S Afr Fam Pract 2017; DOI: 10.1080/20786190.2017.129269
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