195 research outputs found

    Towards malaria elimination - a new thematic series

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    The launch of a new thematic series of Malaria Journal -- "Towards malaria elimination" -- creates the forum that allows carrying scientific evidence on how to achieve malaria elimination in specific endemic settings and conditions into the circles of scientists, public health specialists, national and global programme managers, funders and decision makers

    A mitochondrial mutator plasmid that causes senescence under dietary restricted conditions

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    BACKGROUND: Calorie or dietary restriction extends life span in a wide range of organisms including the filamentous fungus Podospora anserina. Under dietary restricted conditions, P. anserina isolates are several-fold longer lived. This is however not the case in isolates that carry one of the pAL2-1 homologous mitochondrial plasmids. RESULTS: We show that the pAL2-1 homologues act as 'insertional mutators' of the mitochondrial genome, which may explain their negative effect on life span extension. Sequencing revealed at least fourteen unique plasmid integration sites, of which twelve were located within the mitochondrial genome and two within copies of the plasmid itself. The plasmids were able to integrate in their entirety, via a non-homologous mode of recombination. Some of the integrated plasmid copies were truncated, which probably resulted from secondary, post-integrative, recombination processes. Integration sites were predominantly located within and surrounding the region containing the mitochondrial rDNA loci. CONCLUSION: We propose a model for the mechanism of integration, based on innate modes of mtDNA recombination, and discuss its possible link with the plasmid's negative effect on dietary restriction mediated life span extension

    Recurrent Die-Offs of Adult Coho Salmon Returning to Spawn in Puget Sound Lowland Urban Streams

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    Several Seattle-area streams in Puget Sound were the focus of habitat restoration projects in the 1990s. Post-project effectiveness monitoring surveys revealed anomalous behaviors among adult coho salmon returning to spawn in restored reaches. These included erratic surface swimming, gaping, fin splaying, and loss of orientation and equilibrium. Affected fish died within hours, and female carcasses generally showed high rates (>90%) of egg retention. Beginning in the fall of 2002, systematic spawner surveys were conducted to 1) assess the severity of the adult die-offs, 2) compare spawner mortality in urban vs. non-urban streams, and 3) identify water quality and spawner condition factors that might be associated with the recurrent fish kills. The forensic investigation focused on conventional water quality parameters (e.g., dissolved oxygen, temperature, ammonia), fish condition, pathogen exposure and disease status, and exposures to metals, polycyclic aromatic hydrocarbons, and current use pesticides. Daily surveys of a representative urban stream (Longfellow Creek) from 2002–2009 revealed premature spawner mortality rates that ranged from 60–100% of each fall run. The comparable rate in a non-urban stream was <1% (Fortson Creek, surveyed in 2002). Conventional water quality, pesticide exposure, disease, and spawner condition showed no relationship to the syndrome. Coho salmon did show evidence of exposure to metals and petroleum hydrocarbons, both of which commonly originate from motor vehicles in urban landscapes. The weight of evidence suggests that freshwater-transitional coho are particularly vulnerable to an as-yet unidentified toxic contaminant (or contaminant mixture) in urban runoff. Stormwater may therefore place important constraints on efforts to conserve and recover coho populations in urban and urbanizing watersheds throughout the western United States

    Glutathione pathway gene variation and risk of autism spectrum disorders

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    Despite evidence that autism is highly heritable with estimates of 15 or more genes involved, few studies have directly examined associations of multiple gene interactions. Since inability to effectively combat oxidative stress has been suggested as a mechanism of autism, we examined genetic variation 42 genes (308 single-nucleotide polymorphisms (SNPs)) related to glutathione, the most important antioxidant in the brain, for both marginal association and multi-gene interaction among 318 case–parent trios from The Autism Genetic Resource Exchange. Models of multi-SNP interactions were estimated using the trio Logic Regression method. A three-SNP joint effect was observed for genotype combinations of SNPs in glutaredoxin, glutaredoxin 3 (GLRX3), and cystathione gamma lyase (CTH); OR = 3.78, 95% CI: 2.36, 6.04. Marginal associations were observed for four genes including two involved in the three-way interaction: CTH, alcohol dehydrogenase 5, gamma-glutamylcysteine synthetase, catalytic subunit and GLRX3. These results suggest that variation in genes involved in counterbalancing oxidative stress may contribute to autism, though replication is necessary

    Autism-Associated Gene Expression in Peripheral Leucocytes Commonly Observed between Subjects with Autism and Healthy Women Having Autistic Children

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    Autism spectrum disorder (ASD) is a severe neuropsychiatric disorder which has complex pathobiology with profound influences of genetic factors in its development. Although the numerous autism susceptible genes were identified, the etiology of autism is not fully explained. Using DNA microarray, we examined gene expression profiling in peripheral blood from 21 individuals in each of the four groups; young adults with ASD, age- and gender-matched healthy subjects (ASD control), healthy mothers having children with ASD (asdMO), and asdMO control. There was no blood relationship between ASD and asdMO. Comparing the ASD group with control, 19 genes were found to be significantly changed. These genes were mainly involved in cell morphology, cellular assembly and organization, and nerve system development and function. In addition, the asdMO group possessed a unique gene expression signature shown as significant alterations of protein synthesis despite of their nonautistic diagnostic status. Moreover, an ASD-associated gene expression signature was commonly observed in both individuals with ASD and asdMO. This unique gene expression profiling detected in peripheral leukocytes from affected subjects with ASD and unaffected mothers having ASD children suggest that a genetic predisposition to ASD may be detectable even in peripheral cells. Altered expression of several autism candidate genes such as FMR-1 and MECP2, could be detected in leukocytes. Taken together, these findings suggest that the ASD-associated genes identified in leukocytes are informative to explore the genetic, epigenetic, and environmental background of ASD and might become potential tools to assess the crucial factors related to the clinical onset of the disorder

    The case for morphophonological intervention: Evidence from a Greek-speaking child with speech difficulties

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    Intervention with children with speech and language difficulties has been proven beneficial compared with no treatment yet, knowing what type of intervention to provide remains a challenge. Studies of English-speaking children indicate that intervention targeting the production of morphological targets may have a positive effect on phonological aspects and vice versa. However, studies have not reported on generalization effects to untreated morphemes and little is yet known about morphological intervention in the context of a highly inflected language. The purpose of the current intervention case study was to investigate the effect of intervention in relation to phonological and morphological targets in Greek, a language characterized by complex inflectional morphology. A single subject research design was used with pre- and post-intervention assessment carried out. The participant was a four-year-old Greek-speaking boy with speech difficulties. The production of /s/, a phoneme used in multiple phonological and morphological contexts was targeted with alternating focus of intervention between phonological and morphological targets. Assessment took place at two levels: macro-assessment to monitor broad changes in speech; micro-assessment to measure therapy-specific changes in the production of treated targets and generalization to untreated targets and control items. There were four phases of intervention with a total of 24 hours of therapy. Significant improvement in performance accuracy was found between assessment scores immediately pre- and post-intervention. Intervention targeting the production of a phoneme in the word stem was not sufficient to accomplish the accurate production of morphemes requiring the same phoneme; intervention directly targeting morphemes was successful. Within-domain generalization was observed in both domains. Improved naming accuracy was observed post-intervention that was maintained at follow-up. The present study supports the case for morphophonological intervention. Morphological elements should be addressed in a comprehensive intervention for speech sound disorders

    The Regulatory Gift: Politics, regulation and governance

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    Abstract: This article introduces the β€˜regulatory gift’ as a conceptual framework for understanding a particular form of government-led deregulation that is presented as central to the public interest. Contra to theories of regulatory capture, government corruption, β€˜insider’ personal interest or profit-seeking theories of regulation, the regulatory gift describes reform which is overtly designed by Government to reduce or reorient regulators’ functions to the advantage of the regulated and in line with market objectives on a potentially macro (rather than industry-specific) scale. As a conceptual framework, the regulatory gift is intended to be applicable across regulated sectors of democratic states and in this article the empirical sections evidence the practice of regulatory gifting in contemporary UK politics. Specifically, this article analyses the UK Public Bodies Act (2011), affecting some 900 regulatory public bodies and its correlative legislation, the Regulator’s Code (2014), the Deregulation Act (2015) and the Enterprise Bill (2016). The article concludes that whilst the regulatory gift may, in some cases, be aligned with the public interest - delivering on cost reduction, enhancing efficiency and stimulating innovation - this will not always be the case. As the case study of the regulatory body, the UK Human Fertilisation and Embryology Authority (HFEA) demonstrates, despite the explicit claims made by legislators, the regulatory gift has the potential to significantly undermine the public interest

    Ab Initio Identification of Novel Regulatory Elements in the Genome of Trypanosoma brucei by Bayesian Inference on Sequence Segmentation

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    Background: The rapid increase in the availability of genome information has created considerable demand for both comparative and ab initio predictive bioinformatic analyses. The biology laid bare in the genomes of many organisms is often novel, presenting new challenges for bioinformatic interrogation. A paradigm for this is the collected genomes of the kinetoplastid parasites, a group which includes Trypanosoma brucei the causative agent of human African trypanosomiasis. These genomes, though outwardly simple in organisation and gene content, have historically challenged many theories for gene expression regulation in eukaryotes. Methodology/Principle Findings: Here we utilise a Bayesian approach to identify local changes in nucleotide composition in the genome of T. brucei. We show that there are several elements which are found at the starts and ends of multicopy gene arrays and that there are compositional elements that are common to all intergenic regions. We also show that there is a composition-inversion element that occurs at the position of the trans-splice site. Conclusions/Significance: The nature of the elements discovered reinforces the hypothesis that context dependant RN

    Mre11-Rad50 Promotes Rapid Repair of DNA Damage in the Polyploid Archaeon Haloferax volcanii by Restraining Homologous Recombination

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    Polyploidy is frequent in nature and is a hallmark of cancer cells, but little is known about the strategy of DNA repair in polyploid organisms. We have studied DNA repair in the polyploid archaeon Haloferax volcanii, which contains up to 20 genome copies. We have focused on the role of Mre11 and Rad50 proteins, which are found in all domains of life and which form a complex that binds to and coordinates the repair of DNA double-strand breaks (DSBs). Surprisingly, mre11 rad50 mutants are more resistant to DNA damage than the wild-type. However, wild-type cells recover faster from DNA damage, and pulsed-field gel electrophoresis shows that DNA double-strand breaks are repaired more slowly in mre11 rad50 mutants. Using a plasmid repair assay, we show that wild-type and mre11 rad50 cells use different strategies of DSB repair. In the wild-type, Mre11-Rad50 appears to prevent the repair of DSBs by homologous recombination (HR), allowing microhomology-mediated end-joining to act as the primary repair pathway. However, genetic analysis of recombination-defective radA mutants suggests that DNA repair in wild-type cells ultimately requires HR, therefore Mre11-Rad50 merely delays this mode of repair. In polyploid organisms, DSB repair by HR is potentially hazardous, since each DNA end will have multiple partners. We show that in the polyploid archaeon H. volcanii the repair of DSBs by HR is restrained by Mre11-Rad50. The unrestrained use of HR in mre11 rad50 mutants enhances cell survival but leads to slow recovery from DNA damage, presumably due to difficulties in the resolution of DNA repair intermediates. Our results suggest that recombination might be similarly repressed in other polyploid organisms and at repetitive sequences in haploid and diploid species
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