104 research outputs found
Synchronous seasonality in the gut microbiota of wild mouse populations
The gut microbiome performs many important functions in mammalian hosts, with community composition shaping its functional role. However, the factors that drive individual microbiota variation in wild animals and to what extent these are predictable or idiosyncratic across populations remains poorly understood. Here, we use a multi-population dataset from a common rodent species (the wood mouse, Apodemus sylvaticus), to test whether a consistent âcoreâ gut microbiota is identifiable in this species, and to what extent the predictors of microbiota variation are consistent across populations. Between 2014 and 2018 we used capture-mark-recapture and 16S rRNA profiling to intensively monitor two wild wood mouse populations and their gut microbiota, as well as characterising the microbiota from a laboratory-housed colony of the same species. Although the microbiota was broadly similar at high taxonomic levels, the two wild populations did not share a single bacterial amplicon sequence variant (ASV), despite being only 50km apart. Meanwhile, the laboratory-housed colony shared many ASVs with one of the wild populations from which it is thought to have been founded decades ago. Despite not sharing any ASVs, the two wild populations shared a phylogenetically more similar microbiota than either did with the colony, and the factors predicting compositional variation in each wild population were remarkably similar. We identified a strong and consistent pattern of seasonal microbiota restructuring that occurred at both sites, in all years, and within individual mice. While the microbiota was highly individualised, some seasonal convergence occurred in late winter/early spring. These findings reveal highly repeatable seasonal gut microbiota dynamics in multiple populations of this species, despite different taxa being involved. This provides a platform for future work to understand the drivers and functional implications of such predictable seasonal microbiome restructuring, including whether it might provide the host with adaptive seasonal phenotypic plasticity
Abordagem por CompetĂȘncias no CurrĂculo Escolar em Cabo Verde: Desfazendo EquĂvocos para uma Mudança Significativa nas PolĂticas e PrĂĄxis Educacionais
A abordagem curricular por competĂȘncias, enquanto fenĂłmeno recente no discurso educativo em Cabo Verde, corre o risco de nĂŁo passar de mero modismo, sem se traduzir numa inovação efectiva ao nĂvel das prĂĄxis educacionais, se nĂŁo for correctamente compreendida pelos diversos actores envolvidos na obra educativa e, em particular, nos processos de deliberação, gestĂŁo e realização dos currĂculos escolares. O presente artigo procura esclarecer alguns equĂvocos que em Cabo Verde, como em outras latitudes, acompanham a defesa da pedagogia por competĂȘncias. Assim, importa elucidar que a abordagem curricular por competĂȘncias vem aprofundar, entre outras, as abordagens por conteĂșdos e por objectivos e nĂŁo, pura e simplesmente, substituĂ-las, por serem, alegadamente, tradicionais. Outrossim, no contexto da educação escolar, as competĂȘncias nĂŁo devem ser encaradas numa perspectiva redutora, focalizada na transferibilidade de conhecimentos para o mercado de trabalho, mas, fundamentalmente, no sentido da mobilização do conhecimento escolar para a resolução dos problemas nos diversos contextos ou situaçÔes da vida, que nĂŁo se esgota no mercado
Cross-Reactivity of Herpesvirus-Specific CD8 T Cell Lines Toward Allogeneic Class I MHC Molecules
Although association between persistent viral infection and allograft rejection is well characterized, few examples of T-cell cross-reactivity between self-MHC/viral and allogeneic HLA molecules have been documented so far. We appraised in this study the alloreactivity of CD8 T cell lines specific for immunodominant epitopes from human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV). CD8 T cell lines were generated after sorting with immunomagnetic beads coated with either pp65495â503/A*0201, BMLF1259â267/A*0201, or BZLF154â64/B*3501 multimeric complexes. Alloreactivity of the CD8 T cell lines against allogeneic class I MHC alleles was assessed by screening of (i) TNF-α production against COS-7 cells transfected with as many as 39 individual HLA class I-encoding cDNA, and (ii) cytotoxicity activity toward a large panel of HLA-typed EBV-transformed B lymphoblastoid cell lines. We identified several cross-reactive pp65/A*0201-specific T cell lines toward allogeneic HLA-A*3001, A*3101, or A*3201. Moreover, we described here cross-recognition of HLA-Cw*0602 by BZLF1/B*3501-specific T cells. It is noteworthy that these alloreactive CD8 T cell lines showed efficient recognition of endothelial cells expressing the relevant HLA class I allele, with high level TNF-α production and cytotoxicity activity. Taken together, our data support the notion that herpes virus-specific T cells recognizing allo-HLA alleles may promote solid organ rejection
Beyond the water column: aquatic hyphomycetes outside their preferred habitat
Aquatic hyphomycetes have adapted to running waters by their uncommon conidial shape, which facilitates dispersal as well as adherence to plant substrata. However, they have been early and regularly reported to occur in a variety of environments other than their preferred habitat (e.g., in lentic freshwaters, brackish and marine environments, in terrestrial niches such as stream banks, dew, canopy waters and tree holes). In addition, several aquatic hyphomycetes have adapted to a mutualistic lifestyle which may involve plant defence, as endophytes in leaves, gymnosperm needles, orchids and terrestrial roots. There are several lines of evidence suggesting that aquatic hyphomycetes survive under terrestrial conditions due to their sexual states. Although exhibiting higher diversity in pristine streams, aquatic hyphomycetes can survive environmental stress, e.g., pollution or river intermittency. They also inhabit ground and hyporheic waters, where they appear to be subjected to both physical and physiological selection. Appropriate methods including molecular ones should provide a more comprehensive view of the occurrence and ecological roles of aquatic hyphomycetes outside their preferred habitat
Prevalence of chronic HCV infection in EU/EEA countries in 2019 using multiparameter evidence synthesis
Publisher Copyright: © 2023 The Author(s)Background: Epidemiological data are crucial to monitoring progress towards the 2030 Hepatitis C Virus (HCV) elimination targets. Our aim was to estimate the prevalence of chronic HCV infection (cHCV) in the European Union (EU)/European Economic Area (EEA) countries in 2019. Methods: Multi-parameter evidence synthesis (MPES) was used to produce national estimates of cHCV defined as: Ï = ÏrecÏrec + ÏexÏex + ÏnonÏnon; Ïrec, Ïex, and Ïnon represent cHCV prevalence among recent people who inject drugs (PWID), ex-PWID, and non-PWID, respectively, while Ïrec, Ïex, and Ïnon represent the proportions of these groups in the population. Information sources included the European Centre for Disease Prevention and Control (ECDC) national operational contact points (NCPs) and prevalence database, the European Monitoring Centre for Drugs and Drug Addiction databases, and the published literature. Findings: The cHCV prevalence in 29 of 30 EU/EEA countries in 2019 was 0.50% [95% Credible Interval (CrI): 0.46%, 0.55%]. The highest cHCV prevalence was observed in the eastern EU/EEA (0.88%; 95% CrI: 0.81%, 0.94%). At least 35.76% (95% CrI: 33.07%, 38.60%) of the overall cHCV prevalence in EU/EEA countries was associated with injecting drugs. Interpretation: Using MPES and collaborating with ECDC NCPs, we estimated the prevalence of cHCV in the EU/EEA to be low. Some areas experience higher cHCV prevalence while a third of prevalent cHCV infections was attributed to PWID. Further efforts are needed to scale up prevention measures and the diagnosis and treatment of infected individuals, especially in the east of the EU/EEA and among PWID. Funding: ECDC.Peer reviewe
Time to Switch to Second-line Antiretroviral Therapy in Children With Human Immunodeficiency Virus in Europe and Thailand.
Background: Data on durability of first-line antiretroviral therapy (ART) in children with human immunodeficiency virus (HIV) are limited. We assessed time to switch to second-line therapy in 16 European countries and Thailand. Methods: Children aged <18 years initiating combination ART (â„2 nucleoside reverse transcriptase inhibitors [NRTIs] plus nonnucleoside reverse transcriptase inhibitor [NNRTI] or boosted protease inhibitor [PI]) were included. Switch to second-line was defined as (i) change across drug class (PI to NNRTI or vice versa) or within PI class plus change of â„1 NRTI; (ii) change from single to dual PI; or (iii) addition of a new drug class. Cumulative incidence of switch was calculated with death and loss to follow-up as competing risks. Results: Of 3668 children included, median age at ART initiation was 6.1 (interquartile range (IQR), 1.7-10.5) years. Initial regimens were 32% PI based, 34% nevirapine (NVP) based, and 33% efavirenz based. Median duration of follow-up was 5.4 (IQR, 2.9-8.3) years. Cumulative incidence of switch at 5 years was 21% (95% confidence interval, 20%-23%), with significant regional variations. Median time to switch was 30 (IQR, 16-58) months; two-thirds of switches were related to treatment failure. In multivariable analysis, older age, severe immunosuppression and higher viral load (VL) at ART start, and NVP-based initial regimens were associated with increased risk of switch. Conclusions: One in 5 children switched to a second-line regimen by 5 years of ART, with two-thirds failure related. Advanced HIV, older age, and NVP-based regimens were associated with increased risk of switch
The dynamics of wild woodland rodents
This thesis investigates the variation of life history traits within species, how they underpin population dynamics in woodland rodent populations and how they are effected by interactions between species. We ask how do life history traits differ between populations of the same species in similar habitats? We then go on to ask how two different species living in sympatry differ and the possible effects of interactions. We used data collected against three populations of Columbian ground squirrels (Urocitellus columbianus) in Canada and two species of woodland rodents from a site in the UK. Integral Projection Models or IPMs were used to compare the three populations of Columbain ground squirrels and identify differences between them. By using a form of perturbation analysis on the IPMs it was possible to identify the driving demographic and trait transition functions for the differences between the three populations. We then looked at interactions between wood mice (Apodemus sylvaticus) and the bank vole (Myodes glareolus) in the UK, and the possible effect on trapping bias. As data was limited for the two UK species, we could not construct a full IPM, but instead looked at the differences in growth rates of both species to determine what was the most important factors. Comparing the population level estimates from the IPMs for the Columbian ground squirrels, revealed significant differences between the populations. In particular the populations differed in growth rate (λ), generation length and R0. Perturbation analysis of the three IPMs revealed the adult survival function to be the major contributor to the differences between the three population. The inheritance function also had a large impact on the offspring estimates. For the two UK rodent species we found a large impact on the trapping bias due to interactions between the two species. With a significant increase in the chance of the same species being caught within a trap as previously caught. When analysing growth rates, we found that environmental factors only impacted growth for some groups, and we suggest that this may be due to the mitigation by the woodland of impacts of the environmental conditions. We did find that the density of a third species, the yellow necked mouse (Apodemus flavicollis), did have a large negative impact on growth rates on the other two species. In summary species population dynamics can very considerably between populations, even when the populations exist in potentially similar habitats. It is also possible for species living in sympatry to also have an impact on each otherâs population dynamics. Extreme care should then be taken when making comparisons between species based solely on single population data.</p
The dynamics of wild woodland rodents
This thesis investigates the variation of life history traits within species, how they underpin population dynamics in woodland rodent populations and how they are effected by interactions between species. We ask how do life history traits differ between populations of the same species in similar habitats? We then go on to ask how two different species living in sympatry differ and the possible effects of interactions. We used data collected against three populations of Columbian ground squirrels (Urocitellus columbianus) in Canada and two species of woodland rodents from a site in the UK. Integral Projection Models or IPMs were used to compare the three populations of Columbain ground squirrels and identify differences between them. By using a form of perturbation analysis on the IPMs it was possible to identify the driving demographic and trait transition functions for the differences between the three populations. We then looked at interactions between wood mice (Apodemus sylvaticus) and the bank vole (Myodes glareolus) in the UK, and the possible effect on trapping bias. As data was limited for the two UK species, we could not construct a full IPM, but instead looked at the differences in growth rates of both species to determine what was the most important factors.
Comparing the population level estimates from the IPMs for the Columbian ground squirrels, revealed significant differences between the populations. In particular the populations differed in growth rate (λ), generation length and R0. Perturbation analysis of the three IPMs revealed the adult survival function to be the major contributor to the differences between the three population. The inheritance function also had a large impact on the offspring estimates.
For the two UK rodent species we found a large impact on the trapping bias due to interactions between the two species. With a significant increase in the chance of the same species being caught within a trap as previously caught. When analysing growth rates, we found that environmental factors only impacted growth for some groups, and we suggest that this may be due to the mitigation by the woodland of impacts of the environmental conditions. We did find that the density of a third species, the yellow necked mouse (Apodemus flavicollis), did have a large negative impact on growth rates on the other two species.
In summary species population dynamics can very considerably between populations, even when the populations exist in potentially similar habitats. It is also possible for species living in sympatry to also have an impact on each otherĂąs population dynamics. Extreme care should then be taken when making comparisons between species based solely on single population data.</p
GIS dataset of high-resolution rebound surfaces and ice-free paleotopography of glaciated North America since the LGM based on the ICE-xG (VMy) models' predictions
The postglacial rebound is component of the glacial isostatic adjustment which causes the Earth's crust to rebound in regions formerly covered by or adjacent to ice sheets, and subside beneath ocean basins. In North America, the observed postglacial rebound is mainly the result of the Laurentide Ice Sheet deglaciation after it reached its maximum thickness and extent at the Last Glacial Maximum (26.5-19 ka). Global-scale numerical models of glacial isostatic adjustment faithfully reproduce past and current changes in postglacial rebound, but the integration their predictions in a geographic information system to facilitate high-resolution paleotopographic reconstructions remains challenging. We therefore present high-resolution raster datasets of land-deformation and ice-free paleotopography of glaciated North America for several time slices since the Last Glacial Maximum to support geological, paleoenvironmental and archeological studies
Effects of feeding quercetin and flavone on hepatic drug metabolizing enzymes of rat
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