25 research outputs found
Metapopulation dynamics and the influence of the killer system in a natural S. cerevisiae population
No full textParasite infection and the movement of the aquatic snail Potamopyrgus antipodarum along a depth cline
No full textAbstract Parasite species that use two or more host species during their life cycle depend on successful transmission between these species. These successive host species may have different habitat requirements. For example, one host species may be aquatic while the other is terrestrial. To overcome this complicating factor in transmission, a wide diversity of parasite species have adaptations that alter the habitat preference in one host species to facilitate transmission to the next host species. Two common trematode parasites in New Zealand, Atriophallophorus winterbourni and Notocotylus spp., both have a life cycle with two host species. The aquatic snail Potamopyrgus antipodarum is the intermediate host, from which the parasites require transmission to dabbling ducks or other waterfowl. Of these parasites, A. winterbourni is most frequently found in snails from the shallow‐water margin. This may indicate parasite‐induced movement of infected snails into the foraging habitat of dabbling ducks. To test whether the parasites manipulate the snails to move into shallow water, we stretched tubular mesh cages across depth‐specific ecological habitat zones in a lake. Both infected and healthy snails were released into the cages. After 11 days, significantly higher infection frequencies of A. winterbourni were retrieved from the shallowest end of the cages, while Notocotylus spp. frequencies did not vary with depth. The hypothesis that A. winterbourni induces its snail host to move into the shallow‐water habitat cannot be rejected based on the experimental results. Although further research is needed to address alternative explanations, the depth preference of infected snails may be due to a parasite adaptation that facilitates trophic transmission of parasites to dabbling ducks
Infection by dsRNA viruses is associated with enhanced sporulation efficiency in Saccharomyces cerevisiae
No full textISSN:2045-775
Armed violence and poverty in El Salvador: a mini case study for the Armed Violence and Poverty Initiative
No full textYesThis report on El Salvador is one of 13 case studies (all of the case studies can be found at www.bradford.ac.uk/cics). This research draws upon secondary data sources including existing research studies, reports and evaluations commissioned by operational agencies, and early warning and survey data where this has been available. These secondary sources have been complemented by interviews with government officers, aid policymakers and practitioners, researchers and members of the local population. The analysis and opinions expressed in this report are those of the author and do not necessarily represent the views or policy of DFID or the UK government
The interplay of past and current stress exposure on the water flea Daphnia magna
No full text1. Natural populations are exposed to multiple stressors, including both anthropogenic challenges such as xenobiotics and natural stressors associated with exposure to parasites and predators. While there is increasing concern and interest in the combined impact of current exposure to multiple stressors, little attention has been given to how past exposure to a stressor and its evolutionary response shapes the effects of current stressors. 2. Here, we performed a life‐table experiment using the water flea Daphnia magna to study combined effects of current exposure to the pesticide carbaryl, parasite spores and fish predation risk and how these effects depend upon past exposure to carbaryl using clones obtained from a previous carbaryl selection experiment. 3. The current exposure to all three treatments affected life‐history traits. Exposure to fish kairomones increased intrinsic population growth rate, while carbaryl and parasite exposure decreased this fitness measure. The three treatments interacted only in a few cases: carbaryl and fish kairomone exposure interacted in shaping intrinsic population growth rate and its component individual reproductive performance, yet the latter only in the animals not exposed to carbaryl stress in the past. 4. Our data revealed not only adaptive evolution of carbaryl resistance but also associated evolutionary costs in terms of reduced resistance to parasites, corroborating results of an earlier study. Importantly, both the evolutionary benefits and costs of past exposure to carbaryl stress were conditional on current environmental conditions, exposure to predation risk and parasites, respectively. 5. The emerging pattern showed that past stress interacted with current stress in shaping life history. Such evolution‐driven carry‐over effects across generations have been often ignored and may complicate the prediction of effects of current exposure to single and combined stressors even long after the past stress has disappeared.sponsorship: Carbaryl analyses were carried out in the laboratorium of Prof. Dr W. P. de Voogt [University of Amsterdam, Faculteit der Natuurwetenschappen, Wiskunde en Informatica - Instituut voor Biodiversiteit en Ecosystem Dynamica (IBED)]. Nico van Straalen, Karel Deschamphelaere, Dries Knapen, John Colbourne and two anonymous reviewers gave very valuable comments on earlier versions of this manuscript. MJ enjoyed a PhD fellowship of the IWT, Flanders. This research was financially supported by projects GOA/08/06 and PF/2010/07 of the K.U.Leuven Research Fund and project G.0229.09 of FWO, Flanders. (IWT, Flanders, K.U.Leuven Research Fund|GOA/08/06, K.U.Leuven Research Fund|PF/2010/07, FWO, Flanders|G.0229.09)status: Publishe
Building on 150 Years of Knowledge : The Freshwater Isopod Asellus aquaticus as an Integrative Eco-Evolutionary Model System
No full textInteractions between organisms and their environments are central to how biological diversity arises and how natural populations and ecosystems respond to environmental change. These interactions involve processes by which phenotypes are affected by or respond to external conditions (e.g., via phenotypic plasticity or natural selection) as well as processes by which organisms reciprocally interact with the environment (e.g., via eco-evolutionary feedbacks). Organism-environment interactions can be highly dynamic and operate on different hierarchical levels, from genes and phenotypes to populations, communities, and ecosystems. Therefore, the study of organism-environment interactions requires integrative approaches and model systems that are suitable for studies across different hierarchical levels. Here, we introduce the freshwater isopod Asellus aquaticus, a keystone species and an emerging invertebrate model system, as a prime candidate to address fundamental questions in ecology and evolution, and the interfaces therein. We review relevant fields of research that have used A. aquaticus and draft a set of specific scientific questions that can be answered using this species. Specifically, we propose that studies on A. aquaticus can help understanding (i) the influence of host-microbiome interactions on organismal and ecosystem function, (ii) the relevance of biotic interactions in ecosystem processes, and (iii) how ecological conditions and evolutionary forces facilitate phenotypic diversification
Author Correction: Comprehensive analysis of chromothripsis in 2,658 human cancers using whole-genome sequencing
No full textauthor correctio
Measurement of the effective B0s→K+K− lifetime
Get PDFA measurement of the effective lifetime is presented using approximately 37 pb−1 of data collected by LHCb during 2010. This quantity can be used to put constraints on contributions from processes beyond the Standard Model in the meson system and is determined by two complementary approaches as
τKK=1.440±0.096 (stat)±0.008 (syst)±0.003 (model) ps
