| 1. |
- Ammunét, Tea
(författare)
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Consequences of asymmetric competition between resident and invasive defoliators: A novel empirically based modelling approach
- 2014
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Ingår i: Theoretical Population Biology. - : Elsevier BV. - 0040-5809 .- 1096-0325. ; 92, s. 107-117
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Tidskriftsartikel (refereegranskat)abstract
- Invasive species can have profound effects on a resident community via indirect interactions among community members. While long periodic cycles in population dynamics can make the experimental observation of the indirect effects difficult, modelling the possible effects on an evolutionary tithe scale may provide the much needed information on the potential threats of the invasive species on the ecosystem. Using empirical data from a recent invasion in northernmost Fennoscandia, we applied adaptive dynamics theory and modelled the long term consequences of the invasion by the winter moth into the resident community. Specifically, we investigated the outcome of the observed short-term asymmetric preferences of generalist predators and specialist parasitoids on the long term population dynamics of the invasive winter moth and resident autumnal moth sharing these natural enemies. Our results indicate that coexistence after the invasion is possible. However, the outcome of the indirect interaction on the population dynamics of the moth species was variable and the dynamics might not be persistent on an evolutionary time scale. In addition, the indirect interactions between the two moth species via shared natural enemies were able to cause asynchrony in the population cycles corresponding to field observations from previous sympatric outbreak areas. Therefore, the invasion may cause drastic changes in the resident community, for example by prolonging outbreak periods of birch-feeding moths, increasing the average population densities of the moths or, alternatively, leading to extinction of the resident moth species or to equilibrium densities of the two, formerly cyclic, herbivores. (c) 2014 Elsevier Inc. All rights reserved.
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| 2. |
- Ammunét, Tea, et al.
(författare)
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Enkla åtgärder kan rädda hästkastanjen
- 2013
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Ingår i: Svampar och insekter : Rapport från Future Forests 2009-2012. ; :2013:5, s. 20-21
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Bokkapitel (populärvet., debatt m.m.)
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| 3. |
- Ammunét, Tea
(författare)
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Invading and resident defoliators in a changing climate: cold tolerance and predictions concerning extreme winter cold as a range-limiting factor
- 2012
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Ingår i: Ecological Entomology. - : Wiley. - 0307-6946 .- 1365-2311. ; 37, s. 212-220
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Tidskriftsartikel (refereegranskat)abstract
- 1. Winter temperatures in northern latitudes are predicted to increase markedly as a result of ongoing climate change, thus making the invasion of new insect defoliators possible. The establishment of new outbreak pest species may have major effects on northern ecosystems that are particularly sensitive to disturbances. 2. Effects of winter minimum temperatures under field and laboratory conditions were examined and limitations by minimum temperatures on future range expansion were investigated for invasive [Operophtera brumata (Lepidoptera: Geometridae)] and potentially invasive [Agriopis aurantiaria (Lepidoptera: Geometridae)] birch-feeding forest pests. The results for the studied invasive and potentially invasive moths were compared with the parameters of the resident moth species Epirrita autumnata (Lepidoptera: Geometridae). 3. The results showed tolerated critical temperatures of the invader (O. brumata) and the resident (E. autumnata) were more similar (differing only by 1 degrees C), whereas the potential invader (A. aurantiaria) was much less tolerant of cold temperatures. Although describing different stages of overwintering, results were consistent between laboratory and field studies except for those at one field location, at which other abiotic conditions are suggested to have significant influence on moth egg survival. 4. Based on the present results and expected changes in winter temperatures over the next 30 years, the range expansion of an established invasive species may be predicted. No limitations were found regarding the possible future invasion of a new pest species to northern Fennoscandia. The importance of studying a species' whole overwintering period is highlighted and further studies devoted to the effects of other abiotic factors in addition to the effects of temperature are suggested.
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| 4. |
- Ammunét, Tea, et al.
(författare)
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Northern geometrids and climate change: from abiotic factors to trophic interactions
- 2015
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Ingår i: Climate change and insect pests. - 9781780643786 ; 7, s. 235-247
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Bokkapitel (refereegranskat)abstract
- The subarctic mountain birch forests have been periodically disturbed by geometrid moth outbreaks since at least the mid-19th century. The effects of these disturbances can be seen from landscape-level dieback of the birch forest to local-level changes in soil processes. Recent research efforts have demonstrated that the geometrid moth-birch forest system is undergoing changes that could be linked to the ongoing climate warming. Milder winter and spring temperatures influence winter survival and outbreak ranges of the moths, and are also alleviating range expansions and the spread of new species to the area. Moreover, phenology matching with the host plant may be altered. The outcome appears to be intensified outbreaks and a potential for altered species interactions and dynamics with ecosystem-wide consequences.This chapter will first introduce the prevailing dynamics of the mountain birch-geometrid system and the reported ecosystem effects of geometrid outbreaks. Second, the chapter summarizes observations of ongoing abiotic changes in the area and presents the potential known and unknown effects on the study species. Finally, the chapter discusses the future scenarios for this northern ecosystem and the possibility of major ecosystem changes.
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| 5. |
- Andrabi, Syed Bilal Ahmad, et al.
(författare)
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Long noncoding RNA LIRIL2R modulates FOXP3 levels and suppressive function of human CD4+ regulatory T cells by regulating IL2RA
- 2024
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences (PNAS). - 0027-8424 .- 1091-6490. ; 121:23
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Tidskriftsartikel (refereegranskat)abstract
- Regulatory T cells (Tregs) are central in controlling immune responses, and dysregulation of their function can lead to autoimmune disorders or cancer. Despite extensive studies on Tregs, the basis of epigenetic regulation of human Treg development and function is incompletely understood. Long intergenic noncoding RNAs (lincRNA)s are important for shaping and maintaining the epigenetic landscape in different cell types. In this study, we identified a gene on the chromosome 6p25.3 locus, encoding a lincRNA, that was up-regulated during early differentiation of human Tregs. The lincRNA regulated the expression of interleukin-2 receptor alpha (IL2RA), and we named it the lincRNA regulator of IL2RA (LIRIL2R). Through transcriptomics, epigenomics, and proteomics analysis of LIRIL2R-deficient Tregs, coupled with global profiling of LIRIL2R binding sites using chromatin isolation by RNA purification, followed by sequencing, we identified IL2RA as a target of LIRIL2R. This nuclear lincRNA binds upstream of the IL2RA locus and regulates its epigenetic landscape and transcription. CRISPR-mediated deletion of the LIRIL2R-bound region at the IL2RA locus resulted in reduced IL2RA expression. Notably, LIRIL2R deficiency led to reduced expression of Treg-signature genes (e.g., FOXP3, CTLA4, and PDCD1), upregulation of genes associated with effector T cells (e.g., SATB1 and GATA3), and loss of Treg-mediated suppression.
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| 6. |
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| 7. |
- Hugoson, Eric, et al.
(författare)
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Host Adaptation in Legionellales Is 1.9 Ga, Coincident with Eukaryogenesis
- 2022
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Ingår i: Molecular biology and evolution. - : Oxford University Press (OUP). - 0737-4038 .- 1537-1719. ; 39:3
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Tidskriftsartikel (refereegranskat)abstract
- Bacteria adapting to living in a host cell caused the most salient events in the evolution of eukaryotes, namely the seminal fusion with an archaeon, and the emergence of both mitochondrion and chloroplast. A bacterial clade that may hold the key to understanding these events is the deep-branching gammaproteobacterial order Legionellales—containing among others Coxiella and Legionella—of which all known members grow inside eukaryotic cells. Here, by analyzing 35 novel Legionellales genomes mainly acquired through metagenomics, we show that this group is much more diverse than previously thought, and that key host-adaptation events took place very early in its evolution. Crucial virulence factors like the Type IVB secretion (Dot/Icm) system and two shared effector proteins were gained in the last Legionellales common ancestor (LLCA). Many metabolic gene families were lost in LLCA and its immediate descendants, including functions directly and indirectly related to molybdenum metabolism. On the other hand, genome sizes increased in the ancestors of the Legionella genus. We estimate that LLCA lived approximately 1.89 Ga, probably predating the last eukaryotic common ancestor by approximately 0.4–1.0 Gy. These elements strongly indicate that host adaptation arose only once in Legionellales, and that these bacteria were using advanced molecular machinery to exploit and manipulate host cells early in eukaryogenesis.
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| 8. |
- Kalsoom Khan, Faheema, et al.
(författare)
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Naming the untouchable - environmental sequences and niche partitioning as taxonomical evidence in fungi
- 2020
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Ingår i: IMA Fungus. - : BMC. - 2210-6340 .- 2210-6359. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Due to their submerged and cryptic lifestyle, the vast majority of fungal species are difficult to observe and describe morphologically, and many remain known to science only from sequences detected in environmental samples. The lack of practices to delimit and name most fungal species is a staggering limitation to communication and interpretation of ecology and evolution in kingdom Fungi. Here, we use environmental sequence data as taxonomical evidence and combine phylogenetic and ecological data to generate and test species hypotheses in the class Archaeorhizomycetes (Taphrinomycotina, Ascomycota). Based on environmental amplicon sequencing from a well-studied Swedish pine forest podzol soil, we generate 68 distinct species hypotheses of Archaeorhizomycetes, of which two correspond to the only described species in the class. Nine of the species hypotheses represent 78% of the sequenced Archaeorhizomycetes community, and are supported by long read data that form the backbone for delimiting species hypothesis based on phylogenetic branch lengths. Soil fungal communities are shaped by environmental filtering and competitive exclusion so that closely related species are less likely to co-occur in a niche if adaptive traits are evolutionarily conserved. In soil profiles, distinct vertical horizons represent a testable niche dimension, and we found significantly differential distribution across samples for a well-supported pair of sister species hypotheses. Based on the combination of phylogenetic and ecological evidence, we identify two novel species for which we provide molecular diagnostics and propose names. While environmental sequences cannot be automatically translated to species, they can be used to generate phylogenetically distinct species hypotheses that can be further tested using sequences as ecological evidence. We conclude that in the case of abundantly and frequently observed species, environmental sequences can support species recognition in the absences of physical specimens, while rare taxa remain uncaptured at our sampling and sequencing intensity.
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| 9. |
- Klapwijk, Maartje, et al.
(författare)
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Invasiva arter i en föränderlig värld
- 2013
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Ingår i: Svampar och insekter Rapport från Future Forests 2009-2012. ; :2013:5, s. 12-13
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Bokkapitel (populärvet., debatt m.m.)
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| 10. |
- Lehmann, Philipp, et al.
(författare)
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Complex responses of global insect pests to climate warming
- 2020
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Ingår i: Frontiers in Ecology and the Environment. - : Wiley. - 1540-9295 .- 1540-9309. ; 18:3, s. 141-150
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Forskningsöversikt (refereegranskat)abstract
- Although it is well known that insects are sensitive to temperature, how they will be affected by ongoing global warming remains uncertain because these responses are multifaceted and ecologically complex. We reviewed the effects of climate warming on 31 globally important phytophagous (plant-eating) insect pests to determine whether general trends in their responses to warming were detectable. We included four response categories (range expansion, life history, population dynamics, and trophic interactions) in this assessment. For the majority of these species, we identified at least one response to warming that affects the severity of the threat they pose as pests. Among these insect species, 41% showed responses expected to lead to increased pest damage, whereas only 4% exhibited responses consistent with reduced effects; notably, most of these species (55%) demonstrated mixed responses. This means that the severity of a given insect pest may both increase and decrease with ongoing climate warming. Overall, our analysis indicated that anticipating the effects of climate warming on phytophagous insect pests is far from straightforward. Rather, efforts to mitigate the undesirable effects of warming on insect pests must include a better understanding of how individual species will respond, and the complex ecological mechanisms underlying their responses.
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