203 research outputs found

    Evolutionary genetic aspects of host association in generalist ectoparasites

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    Despite the use of the host for dispersal by most parasite species, the extremely loose relationship typical between highly mobile hosts and generalist ectoparasites may lead to very different gene flow patterns between the two, leading in turn to different spatial genetic structure, and potentially different demographic history. I examined how similar gene flow patterns are between Cimex adjunctus, a generalist ectoparasite of bats present throughout North America, and two of its key bat hosts. I first analyzed the continent-scale genetic structure and demographic history of C. adjunctus and compared it to that of two of its hosts, the little brown myotis and the big brown bat, using microsatellite and mitochondrial data. Second, I compared spatial genetic structure of C. adjunctus with Cimex lectularius, or common bed bug, which associates with a broader range of host species. Third, I compared the effect of land cover on spatial genetic structure of C. adjunctus and of the big brown bat in the Great Lakes region. My results support the emerging hypothesis that generalist ectoparasites and their highly mobile hosts display weak, but positive, correlation in spatial genetic structure and demographic history. Generalist parasites associate with different hosts, which are, in some cases, evolutionarily divergent from each other. In such cases, it is not clear how hosts may affect adaptive genetic variation in the parasites. In the Cimex genus, parasite species associate with a range of hosts, including bats, humans, and swallows. I examined how hosts affect adaptive genetic variation in these generalist ectoparasites. I analyzed variation at two salivary protein genes, one coding for an apyrase and the other for a nitrophorin, in 10 species of Cimex. These proteins affect the way parasites feed on their hosts, by preventing clotting and vasoconstriction, and may experience selection depending on host ecology or physiology. I also analyzed allelic divergence at the same two genes in a single species, C. adjunctus, associated with several bat species in North America. My results suggest selection and adaptation to the host at genes coding for salivary proteins of blood-feeding ectoparasites across the Cimex genus, and also within C. adjunctus

    Structure génétique et potentiel de propagation de la rage chez deux mésocarnivores vecteurs le raton laveur(Procyon lotor) et la moufette rayée(Mephitis mephitis)

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    Mon premier objectif spĂ©cifique Ă©tait de dĂ©terminer le niveau de structure gĂ©nĂ©tique et les Ă©lĂ©ments du paysage du Sud du QuĂ©bec qui sont susceptibles d'affecter cette structure gĂ©nĂ©tique chez les moufettes rayĂ©es. J'ai aussi Ă©valuĂ© s'il existe des effets spĂ©cifiques au sexe en comparant la structure gĂ©nĂ©tique entre les mĂąles et les femelles. Pour ce faire, j'ai genotypĂ© Ă  9 loci microsatellites 289 individus capturĂ©s dans les rĂ©gions de la MontĂ©rĂ©gie et de l'Estrie, au QuĂ©bec. Mes rĂ©sultats montrent que la prĂ©sence des riviĂšres Ă  fort dĂ©bit et possiblement aussi des autoroutes provoquent une augmentation de la structure gĂ©nĂ©tique surtout chez les femelles de cette espĂšce. Ces rĂ©sultats suggĂšrent aussi que les mĂąles de la moufette rayĂ©e seraient potentiellement des vecteurs plus actifs dans la propagation de la variante de la rage du raton laveur que les femelles, puisqu'ils ne semblent pas limitĂ©s autant que les femelles par les Ă©lĂ©ments du paysage. Finalement, puisque les mĂąles ne semblent que trĂšs peu limitĂ©s par les barriĂšres potentielles du paysage, celles-ci ne peuvent pas ĂȘtre utilisĂ©es pour contrĂŽler efficacement la propagation de la maladie.Mon deuxiĂšme objectif spĂ©cifique Ă©tait de dĂ©terminer s'il existe une diffĂ©rence de diversitĂ© et/ou de structure gĂ©nĂ©tique entre des ratons laveurs testĂ©s positifs et des ratons laveurs testĂ©s nĂ©gatifs pour la rage. Une telle diffĂ©rence serait un indice d'un comportement de dĂ©placement diffĂ©rent entre ces deux groupes. Ceci peut entre autres me permettre de vĂ©rifier la validitĂ© des rĂ©sultats obtenus en Ă©tudiant des individus sains d'une espĂšce vectrice de la maladie pour tenter d'infĂ©rer le patron de propagation de la rage du raton laveur. Mes rĂ©sultats montrent que la structure gĂ©nĂ©tique ne diffĂšre pas entre les ratons laveurs sains et les ratons laveurs rabiques, indiquant un comportement de dĂ©placement probablement similaire entre les deux groupes. Donc, les Ă©lĂ©ments du paysage auraient possiblement un effet similaire sur les ratons laveurs rabiques et sains. Les Ă©tudes sur la structure gĂ©nĂ©tique chez des ratons laveurs sains pourraient donc fort probablement nous informer sur les couloirs de propagation potentiels de la rage du raton laveur. Ensuite, j'ai tentĂ© de dĂ©terminer si la diversitĂ© gĂ©nĂ©tique pouvait influencer l'infection par la rage en comparant la diversitĂ© gĂ©nĂ©tique Ă  diffĂ©rents loci entre les animaux rabiques et sains. Une diffĂ©rence de diversitĂ© gĂ©nĂ©tique entre les deux groupes pourrait indiquer un plus grand taux d'immigration provenant de populations adjacentes chez un des groupes. Par ailleurs, une grande diversitĂ© gĂ©nĂ©tique pourrait ĂȘtre un Ă©lĂ©ment pouvant potentiellement limiter la propagation de la rage du raton laveur. Or, mes rĂ©sultats ne supportent pas que la diversitĂ© gĂ©nĂ©tique puisse influencer la probabilitĂ© d'un individu d'ĂȘtre infectĂ© par la rage.--RĂ©sumĂ© abrĂ©gĂ© par UMI

    Les effets de la ProximitĂ© sur l’exĂ©cution des politiques publiques : l'exemple d'un Centre de Lutte contre le Cancer (CLCC)

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    Les principes du nouveau management public infusent progressivement le secteur hospitalier, un secteur marquĂ© par de profondes transformations. La maniĂšre dont s'expriment les politiques publiques dans ces Ă©tablissements permet de mettre en Ă©vidence des injonctions paradoxales que les acteurs Ɠuvrant en leur sein tentent de concilier. La mobilisation de la grille de la proximitĂ© apporte une lecture originale des maniĂšres dont les politiques publiques sont exĂ©cutĂ©es pour notamment faire face Ă  ces nouveaux dĂ©fis. Les dimensions de la proximitĂ© sont utilisĂ©es ici pour Ă©tudier la confiance entre les acteurs, le contrĂŽle organisationnel et la lĂ©gitimitĂ© des politiques publiques. La recherche porte sur l'Ă©tude du cas d'un Centre de Lutte Contre le Cancer (CLCC). Cette Ă©tude croise des donnĂ©es secondaires (comptes rendus de rĂ©union, prĂ©sentation du plan stratĂ©gique du Centre, organigramme, rapports de gestion) et des entretiens semi-directifs auprĂšs de personnels des quatre catĂ©gories les plus reprĂ©sentatives du personnel hospitalier (dirigeants, mĂ©decins, personnels de soin, personnel des fonctions support).The principles of the new public management are gradually infusing the hospital sector, a sector marked by deep transformations. The way in which public policies are expressed in these institutions makes it possible to highlight paradoxical injunctions that the actors working with try to reconcile. The mobilization of the proximity grid provides an original reading of the ways in which public policies are implemented in order to face these new challenges. The dimensions of proximity are used here to study trust between actors, organizational control and the legitimacy of public policies. The research focuses on the case study of a French Comprehensive cancer Center (FCCC). This study collates secondary data (meeting reports, presentation of the Center’s strategic plan, organization chart, and management reports) and semi-structured interviews with staff of the four most representative categories of hospital employees (managers, doctors, care, support staff)

    Uncovering spatial variation in maternal healthcare service use at subnational level in Jimma zone, Ethiopia

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    Re-directing resources to vulnerable sub-groups and locations is necessary to ensure equitable progress in maternal health. Analysis of disaggregated national data suggest uneven access to essential maternal healthcare services. Of major concern are women who are the most vulnerable and in need of healthcare services, being least likely to access them. Mapping of core maternal healthcare service-use indicators can serve as a decision-making tool. This analysis focuses on services across the continuum of maternal healthcare: antenatal care, maternity waiting home use, delivery care at health facilities, and postnatal care, in three rural woredas in Jimma Zone, Ethiopia.Global Affairs Canada (GAC)Canadian Institutes of Health Research (CIHR

    Arbovirus vectors of epidemiological concern in the Americas: A scoping review of entomological studies on Zika, dengue and chikungunya virus vectors

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    Background Three arthropod-borne viruses (arboviruses) causing human disease have been the focus of a large number of studies in the Americas since 2013 due to their global spread and epidemiological impacts: Zika, dengue, and chikungunya viruses. A large proportion of infections by these viruses are asymptomatic. However, all three viruses are associated with moderate to severe health consequences in a small proportion of cases. Two mosquito species, Aedes aegypti and Aedes albopictus, are among the worldÂŽs most prominent arboviral vectors, and are known vectors for all three viruses in the Americas. Objectives This review summarizes the state of the entomological literature surrounding the mosquito vectors of Zika, dengue and chikungunya viruses and factors affecting virus transmission. The rationale of the review was to identify and characterize entomological studies that have been conducted in the Americas since the introduction of chikungunya virus in 2013, encompassing a period of arbovirus co-circulation, and guide future research based on identified knowledge gaps. Methods The preliminary search for this review was conducted on PubMed (National Library of Health, Bethesda, MD, United States). The search included the terms ÂŽzikaÂŽ OR ÂŽdengueÂŽ OR ÂŽchikungunyaÂŽ AND ÂŽvectorÂŽ OR ÂŽAedes aegyptiÂŽ OR ÂŽAedes albopictusÂŽ. The search was conducted on March 1st of 2018, and included all studies since January 1st of 2013. Results A total of 96 studies were included in the scoping review after initial screening and subsequent exclusion of out-of-scope studies, secondary data publications, and studies unavailable in English language. Key findings We observed a steady increase in number of publications, from 2013 to 2018, with half of all studies published from January 2017 to March 2018. Interestingly, information on Zika virus vector species composition was abundant, but sparse on Zika virus transmission dynamics. Few studies examined natural infection rates of Zika virus, vertical transmission, or co-infection with other viruses. This is in contrast to the wealth of research available on natural infection and co-infection for dengue and chikungunya viruses, although vertical transmission research was sparse for all three viruses.Fil: Jones, Reilly. University of Toronto; CanadĂĄFil: Kulkarni, Manisha A.. University of Ottawa; CanadĂĄFil: Davidson, Thomas M.V.. University of Toronto; CanadĂĄFil: Sander, Beate. Public Health Ontario; CanadĂĄFil: GonzĂĄlez, Camila. Universidad de Los Andes; VenezuelaFil: Wu, Jianhong. York University ; CanadĂĄFil: Miretti, Marcos Mateo. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Nordeste. Instituto de BiologĂ­a Subtropical. Instituto de BiologĂ­a Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de BiologĂ­a Subtropical. Instituto de BiologĂ­a Subtropical - Nodo Posadas; ArgentinaFil: Espinel, Mauricio. Universidad Laica Elroy Alfaro de ManabĂ­; EcuadorFil: Cevallos Viteri, Varsovia Enid. Instituto Nacional de Salud PĂșblica; EcuadorFil: Cevallos, Varsovia. Instituto Nacional de Salud PĂșblica; EcuadorFil: Talbot, Benoit. University of Ottawa; Canad

    Identification of Melatonin-Regulated Genes in the Ovine Pituitary Pars Tuberalis, a Target Site for Seasonal Hormone Control

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    The pars tuberalis (PT) of the pituitary gland expresses a high density of melatonin (MEL) receptors and is believed to regulate seasonal physiology by decoding changes in nocturnal melatonin secretion. Circadian clock genes are known to be expressed in the PT in response to the decline (Per1) and onset (Cry1) of MEL secretion, but to date little is known of other molecular changes in this key MEL target site. To identify transcriptional pathways that may be involved in the diurnal and photoperiod-transduction mechanism, we performed a whole genome transcriptome analysis using PT RNA isolated from sheep culled at three time points over the 24-h cycle under either long or short photoperiods. Our results reveal 153 transcripts where expression differs between photoperiods at the light-dark transition and 54 transcripts where expression level was more globally altered by photoperiod (all time points combined). Cry1 induction at night was associated with up-regulation of genes coding for NeuroD1 (neurogenic differentiation factor 1), Pbef / Nampt (nicotinamide phosphoribosyltransferase) , Hif1α (hypoxia-inducible factor-1α), and Kcnq5 (K channel) and down-regulation of RorÎČ, a key clock gene regulator. Using in situ hybridization, we confirmed day-night differences in expression for Pbef / Nampt, NeuroD1, and RorÎČ in the PT. Treatment of sheep with MEL increased PT expression for Cry1, Pbef / Nampt, NeuroD1, and Hif1α, but not Kcnq5. Our data thus reveal a cluster of Cry1-associated genes that are acutely responsive to MEL and novel transcriptional pathways involved in MEL action in the PT

    Combining genotype, phenotype and environment to infer potential candidate genes: An example using the Loblolly pine (Pinus taeda)

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    Population genomic analyses can be an important tool in understanding local adaptation. Identification of potential adaptive loci in such analyses is usually based on the survey of a large genomic dataset in combination with environmental variables. Phenotypic data are less commonly incorporated into such studies, although combining a genome scan analysis with a phenotypic trait analysis can greatly improve the insights obtained from each analysis individually. Here, we aimed to identify loci potentially involved in adaptation to climate in 283 Loblolly pine (Pinus taeda) samples from throughout the species’ range in the southeastern United States. We analyzed associations between phenotypic, molecular and environmental variables from a published dataset of 3,082 SNP loci and published datasets containing three categories of phenotypic traits (gene expression, metabolites, and whole-plant traits). We found only six SNP loci that displayed potential signals of local adaptation. Five of the six identified SNPs are linked to gene expression traits for lignin development, and one is linked with whole-plant traits. We subsequently compared the six candidate genes with environmental variables and found a high correlation in only three of them (R2 > 0.2). Our study highlights the need for a combination of genotypes, phenotypes, and environmental variables, and for an appropriate sampling scheme and study design, to improve confidence in the identification of potential candidate genes

    Genome analysis of the necrotrophic fungal pathogens Sclerotinia sclerotiorum and Botrytis cinerea

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    Sclerotinia sclerotiorum and Botrytis cinerea are closely related necrotrophic plant pathogenic fungi notable for their wide host ranges and environmental persistence. These attributes have made these species models for understanding the complexity of necrotrophic, broad host-range pathogenicity. Despite their similarities, the two species differ in mating behaviour and the ability to produce asexual spores. We have sequenced the genomes of one strain of S. sclerotiorum and two strains of B. cinerea. The comparative analysis of these genomes relative to one another and to other sequenced fungal genomes is provided here. Their 38–39 Mb genomes include 11,860–14,270 predicted genes, which share 83% amino acid identity on average between the two species. We have mapped the S. sclerotiorum assembly to 16 chromosomes and found large-scale co-linearity with the B. cinerea genomes. Seven percent of the S. sclerotiorum genome comprises transposable elements compared t

    Genomic analysis of the necrotrophic fungal pathogens Sclerotinia sclerotiorum and Botrytis cinerea

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    This is the final version of the article. Available from the publisher via the DOI in this record.Sclerotinia sclerotiorum and Botrytis cinerea are closely related necrotrophic plant pathogenic fungi notable for their wide host ranges and environmental persistence. These attributes have made these species models for understanding the complexity of necrotrophic, broad host-range pathogenicity. Despite their similarities, the two species differ in mating behaviour and the ability to produce asexual spores. We have sequenced the genomes of one strain of S. sclerotiorum and two strains of B. cinerea. The comparative analysis of these genomes relative to one another and to other sequenced fungal genomes is provided here. Their 38-39 Mb genomes include 11,860-14,270 predicted genes, which share 83% amino acid identity on average between the two species. We have mapped the S. sclerotiorum assembly to 16 chromosomes and found large-scale co-linearity with the B. cinerea genomes. Seven percent of the S. sclerotiorum genome comprises transposable elements compared to <1% of B. cinerea. The arsenal of genes associated with necrotrophic processes is similar between the species, including genes involved in plant cell wall degradation and oxalic acid production. Analysis of secondary metabolism gene clusters revealed an expansion in number and diversity of B. cinerea-specific secondary metabolites relative to S. sclerotiorum. The potential diversity in secondary metabolism might be involved in adaptation to specific ecological niches. Comparative genome analysis revealed the basis of differing sexual mating compatibility systems between S. sclerotiorum and B. cinerea. The organization of the mating-type loci differs, and their structures provide evidence for the evolution of heterothallism from homothallism. These data shed light on the evolutionary and mechanistic bases of the genetically complex traits of necrotrophic pathogenicity and sexual mating. This resource should facilitate the functional studies designed to better understand what makes these fungi such successful and persistent pathogens of agronomic crops.The Sclerotinia sclerotiorum genome project was supported by the USDA Cooperative State Research, Education and Extension Service (USDA-NRI 2004). Sclerotinia sclerotiorum ESTs were funded by a grant to JA Rollins from USDA specific cooperative agreement 58-5442-4-281. The genome sequence of Botrytis cinerea strain T4 was funded by Genoscope, CEA, France. M Viaud was funded by the “Projet INRA Jeune-Equipe”. PM Coutinho and B Henrissat were funded by the ANR to project E-Tricel (grant ANR-07-BIOE-006). The CAZy database is funded in part by GIS-IBiSA. DM Soanes and NJ Talbot were partly funded by the UK Biotechnology and Biological Sciences Research Council. KM Plummer was partially funded by the New Zealand Bio-Protection Research Centre, http://bioprotection.org.nz/. BJ Howlett and A Sexton were partially funded by the Australian Grains Research and Development Corporation, www.grdc.com.au. L Kohn was partially funded by NSERC Discovery Grant (Natural Sciences and Engineering Research Council of Canada) - Grant number 458078. M Dickman was supported by the NSF grant MCB-092391 and BARD grant US-4041-07C. O Yarden was supported by BARD grant US-4041-07C. EG Danchin obtained financial support from the European Commission (STREP FungWall grant, contract: LSHB - CT- 2004 - 511952). A Botrytis Genome Workshop (Kaiserslautern, Germany) was supported by a grant from the German Science Foundation (DFG; HA1486) to M Hahn

    Insulin in the nervous system and the mind: Functions in metabolism, memory, and mood

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    Background: Insulin, a pleotrophic hormone, has diverse effects in the body. Recent work has highlighted the important role of insulin's action in the nervous system on glucose and energy homeostasis, memory, and mood. Scope of review: Here we review experimental and clinical work that has broadened the understanding of insulin's diverse functions in the central and peripheral nervous systems, including glucose and body weight homeostasis, memory and mood, with particular emphasis on intranasal insulin. Major conclusions: Implications for the treatment of obesity, type 2 diabetes, dementia, and mood disorders are discussed in the context of brain insulin action. Intranasal insulin may have potential in the treatment of central nervous system-related metabolic disorders. Keywords: Insulin, Intranasal insulin, Memory, Metabolism, Moo
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