34 research outputs found

    The Valgent4 protocol:Robust analytical and clinical validation of 11 HPV assays with genotyping on cervical samples collected in SurePath medium

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    BACKGROUND: The VALidation of HPV GENoyping Tests (VALGENT) is an international initiative designed to validate HPV assays with genotyping capability. The VALGENT4 protocol differs from previous VALGENT installments as the sample collection medium is SurePath, and exclusively includes samples from women ≥30 years of age which is concordant with the majority of HPV primary screening guidelines. Here we present the protocol for the fourth installment of the VALGENT framework. OBJECTIVES: In VALGENT4 11 HPV assays will be evaluated using two comparator assays based on PCR with the GP5+/6+ primers. STUDY DESIGN: Overall, the VALGENT4 panel consists of 1,297 routine samples comprised of 998 unselected, consecutive samples, of which 51 samples had abnormal cytology with 13 women diagnosed with ≥CIN2, and 299 consecutive samples enriched for ≥ASCUS cytology (100 ASCUS, 100 LSIL, 99 HSIL) with 106 ≥CIN2 upon follow up. Manipulated and DNA extracted panel samples were characterized with respect to human beta globin (HBB) and overall DNA content and composition to quality assess the panel prior to distribution to the collaborating sites. RESULT: The relative cellularity (mean CT value of HBB from the Onclarity assay) on the 1,297 LBC samples (CT=24.8) was compared with 293 un-manipulated routine cytology screening samples (CT=23.8). Furthermore, the DNA extracted panel samples was characterized using the Exome iPLEX pro assay, which reports amplifiable copies on individual samples as well as copies of five different base pair lengths. Here the data showed a slightly lower number of amplifiable DNA copies (ratio: 0.7, p=<0.01)) in the VALGENT4 panel samples compared to routine extracted cervical DNA samples CONCLUSION: The present manuscript details the manipulation, processing and quality assessment of samples used in VALGENT-4. This methodological document may be of value for future international projects of HPV test validation

    Forest microclimates and climate change: importance, drivers and future research agenda

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    Forest microclimates contrast strongly with the climate outside forests. To fully understand and better predict how forests' biodiversity and functions relate to climate and climate change, microclimates need to be integrated into ecological research. Despite the potentially broad impact of microclimates on the response of forest ecosystems to global change, our understanding of how microclimates within and below tree canopies modulate biotic responses to global change at the species, community and ecosystem level is still limited. Here, we review how spatial and temporal variation in forest microclimates result from an interplay of forest features, local water balance, topography and landscape composition. We first stress and exemplify the importance of considering forest microclimates to understand variation in biodiversity and ecosystem functions across forest landscapes. Next, we explain how macroclimate warming (of the free atmosphere) can affect microclimates, and vice versa, via interactions with land-use changes across different biomes. Finally, we perform a priority ranking of future research avenues at the interface of microclimate ecology and global change biology, with a specific focus on three key themes: (1) disentangling the abiotic and biotic drivers and feedbacks of forest microclimates; (2) global and regional mapping and predictions of forest microclimates; and (3) the impacts of microclimate on forest biodiversity and ecosystem functioning in the face of climate change. The availability of microclimatic data will significantly increase in the coming decades, characterizing climate variability at unprecedented spatial and temporal scales relevant to biological processes in forests. This will revolutionize our understanding of the dynamics, drivers and implications of forest microclimates on biodiversity and ecological functions, and the impacts of global changes. In order to support the sustainable use of forests and to secure their biodiversity and ecosystem services for future generations, microclimates cannot be ignored.Peer reviewe

    Sex-related differences in aging rate are associated with sex chromosome system in amphibians

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    Sex-related differences in mortality are widespread in the animal kingdom. Although studies have shown that sex determination systems might drive lifespan evolution, sex chromosome influence on aging rates have not been investigated so far, likely due to an apparent lack of demographic data from clades including both XY (with heterogametic males) and ZW (heterogametic females) systems. Taking advantage of a unique collection of capture-recapture datasets in amphibians, a vertebrate group where XY and ZW systems have repeatedly evolved over the past 200 million years, we examined whether sex heterogamy can predict sex differences in aging rates and lifespans. We showed that the strength and direction of sex differences in aging rates (and not lifespan) differ between XY and ZW systems. Sex-specific variation in aging rates was moderate within each system, but aging rates tended to be consistently higher in the heterogametic sex. This led to small but detectable effects of sex chromosome system on sex differences in aging rates in our models. Although preliminary, our results suggest that exposed recessive deleterious mutations on the X/Z chromosome (the "unguarded X/Z effect") or repeat-rich Y/W chromosome (the "toxic Y/W effect") could accelerate aging in the heterogametic sex in some vertebrate clades.Peer reviewe

    The Dangers of Being a Small, Oligotrophic and Light Demanding Freshwater Plant across a Spatial and Historical Eutrophication Gradient in Southern Scandinavia

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    European freshwater habitats have experienced a severe loss of plant diversity, regionally and locally, over the last century or more. One important and well-established driver of change is eutrophication, which has increased with rising population density and agricultural intensification. However, reduced disturbance of lake margins may have played an additional key role. The geographical variation in water chemistry, which has set the scene for – and interacted with – anthropogenic impact, is much less well understood. We took advantage of some recently completed regional plant distribution surveys, relying on hundreds of skilled citizen scientists, and analyzed the hydrophyte richness to environment relations in five contiguous South-Scandinavian regions. For three of the regions, we also assessed changes to the freshwater flora over the latest 50–80 years. We found a considerable variation in background total phosphorus concentrations and alkalinity, both within and between regions. The prevalence of functional groups differed between regions in accordance with the environmental conditions and the species’ tolerance to turbid waters. Similarly, the historical changes within regions followed the same trend in correspondence to the altered environmental conditions over time. Small submerged species decreased relative to tall submerged and floating-leaved species along the regional and historical eutrophication gradients. These changes were accompanied by systematically greater relative abundance of species of higher phosphorus prevalence. We conclude that species traits in close correspondence with anthropogenic impacts are the main determinants of local, regional and historical changes of species distribution and occupancy, while pure biogeography plays a minor role. Conservation measures, such as re-oligotrophication and re-established disturbance regimes through grazing and water level fluctuations, may help reduce the tall reed vegetation, restore the former richness of the freshwater flora and safeguard red-listed species, although extended time delays are anticipated in nutrient-rich regions, in which species only survive at minute abundance in isolated refugia

    The Valgent4 protocol: Robust analytical and clinical validation of 11 HPV assays with genotyping on cervical samples collected in SurePath medium

    No full text
    Background The VALidation of HPV GENoyping Tests (VALGENT) is an international initiative designed to validate HPV assays with genotyping capability. The VALGENT4 protocol differs from previous VALGENT installments as the sample collection medium is SurePath, and exclusively includes samples from women ≥30 years of age which is concordant with the majority of HPV primary screening guidelines. Here we present the protocol for the fourth installment of the VALGENT framework. Objectives In VALGENT4 11 HPV assays will be evaluated using two comparator assays based on PCR with the GP5+/6+ primers. Study design Overall, the VALGENT4 panel consists of 1,297 routine samples comprised of 998 unselected, consecutive samples, of which 51 samples had abnormal cytology with 13 women diagnosed with ≥CIN2, and 299 consecutive samples enriched for ≥ASCUS cytology (100 ASCUS, 100 LSIL, 99 HSIL) with 106 ≥CIN2 upon follow up. Manipulated and DNA extracted panel samples were characterized with respect to human beta globin (HBB) and overall DNA content and composition to quality assess the panel prior to distribution to the collaborating sites. Result The relative cellularity (mean CT value of HBB from the Onclarity assay) on the 1,297 LBC samples (CT=24.8) was compared with 293 un-manipulated routine cytology screening samples (CT=23.8). Furthermore, the DNA extracted panel samples was characterized using the Exome iPLEX pro assay, which reports amplifiable copies on individual samples as well as copies of five different base pair lengths. Here the data showed a slightly lower number of amplifiable DNA copies (ratio: 0.7, p=<0.01)) in the VALGENT4 panel samples compared to routine extracted cervical DNA samples Conclusion The present manuscript details the manipulation, processing and quality assessment of samples used in VALGENT-4. This methodological document may be of value for future international projects of HPV test validation

    Data from: Genetic diversity and distribution patterns of diploid and polyploid hybrid water frog populations (Pelophylax esculentus complex) across Europe

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    Polyploidization is a rare yet sometimes successful way for animals to rapidly create geno- and phenotypes that may colonize new habitats and quickly adapt to environmental changes. In this study, we use water frogs of the Pelophylax esculentus complex, comprising two species (Pelophylax lessonae, genotype LL; Pelophylax ridibundus, RR) and various diploid (LR) and triploid (LLR, LRR) hybrid forms, summarized as P. esculentus, as a model for studying recent hybridization and polyploidization in the context of speciation. Specifically, we compared the geographic distribution and genetic diversity of diploid and triploid hybrids across Europe to understand their origin, maintenance and potential role in hybrid speciation. We found that different hybrid and parental genotypes are not evenly distributed across Europe. Rather, their genetic diversity is structured by latitude and longitude and the presence/absence of parental species but not of triploids. Highest genetic diversity was observed in central and eastern Europe, the lowest in the northwestern parts of Europe. This gradient can be explained by the decrease in genetic diversity during postglacial expansion from southeastern glacial refuge areas. Genealogical relationships calculated on the basis of microsatellite data clearly indicate that hybrids are of multiple origin and include a huge variety of parental genomes. Water frogs in mixed-ploidy populations without any parental species (i.e. all-hybrid populations) can be viewed as evolutionary units that may be on their way towards hybrid speciation. Maintenance of such all-hybrid populations requires a continuous exchange of genomes between diploids and triploids, but scenarios for alternative evolutionary trajectories are discussed

    New particle formation and growth from dimethyl sulfide oxidation by hydroxyl radicals

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    Abstract Dimethyl sulfide (DMS) is produced by plankton in oceans and constitutes the largest natural emission of sulfur to the atmosphere. In this work, we examine new particle formation from the primary pathway of oxidation of gas-phase DMS by OH radicals. We particularly focus on particle growth and mass yield as studied experimentally under dry conditions using the atmospheric simulation chamber AURA. Experimentally, we show that aerosol mass yields from oxidation of 50–200 ppb of DMS are low (2–7%) and that particle growth rates (8.2–24.4 nm/h) are comparable with ambient observations. An HR-ToF-AMS was calibrated using methanesulfonic acid (MSA) to account for fragments distributed across both the organic and sulfate fragmentation table. AMS-derived chemical compositions revealed that MSA was always more dominant than sulfate in the secondary aerosols formed. Modeling using the Aerosol Dynamics, gas- and particle-phase chemistry kinetic multilayer model for laboratory CHAMber studies (ADCHAM) indicates that the Master Chemical Mechanism gas-phase chemistry alone underestimates experimentally observed particle formation and that DMS multiphase and autoxidation chemistry is needed to explain observations. Based on quantum chemical calculations, we conclude that particle formation from DMS oxidation in the ambient atmosphere will most likely be driven by mixed sulfuric acid/MSA clusters clustering with both amines and ammonia
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