| 1. |
- Bergström, Kristofer, et al.
(author)
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Exceptional longevity in northern peripheral populations of Wels catfish (Siluris glanis)
- 2022
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In: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 12:1
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Journal article (peer-reviewed)abstract
- Studies of life-history variation across a species range are crucial for ecological understanding and successful conservation. Here, we examined the growth and age of Wels catfish (Silurus glanis) in Sweden, which represent the northernmost populations in Europe. A total of 1183 individuals were captured, marked and released between 2006 and 2020. Mark-recapture data from 162 individuals (size range: 13-195 cm) were used to estimate von Bertalanffy growth curve parameters which revealed very slow growth rates compared to catfish within the core distribution area (central Europe). The fitted von Bertalanffy growth curve predicted a 150 cm catfish to be around 40 years old, while the largest recaptured individual (length 195 cm) was estimated to be 70 (95% CI 50-112) years old. This was substantially older than the previously documented maximum age of a catfish. The weight at length relationships in these northern peripheral populations were similar to those documented for catfish in central Europe indicating that resources did not constrain growth. This indicates that the slow growth and exceptional high age in the northern catfish populations are the result of lower temperatures and/or local adaptations.
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| 2. |
- Bergström, Kristofer, et al.
(author)
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Seasonal and Daily Movement Patterns by Wels Catfish (Silurus glanis) at the Northern Fringe of Its Distribution Range
- 2024
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In: Fishes. - : MDPI. - 2410-3888. ; 9:7
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Journal article (peer-reviewed)abstract
- Fish behavior often varies across a species' distribution range. Documenting how behaviors vary at fringes in comparison to core habitats is key to understanding the impact of environmental variation and the evolution of local adaptations. Here, we studied the behavior of Wels catfish (Silurus glanis) in Lake M & ouml;ckeln, Sweden, which represent a European northern fringe population. Adult individuals (101-195 cm, N = 55) were caught and externally marked with data storage tags (DSTs). Fifteen DSTs were recovered a year after tagging, of which 11 tags contained long-term high-resolution behavioral data on the use of vertical (depth) and thermal habitats. This showed that the catfish already became active in late winter (<5 degrees C) and displayed nocturnal activity primarily during summer and late autumn. The latter included a transition from the bottom to the surface layer at dusk, continuous and high activity close to the surface during the night, and then descent back to deeper water at dawn. During the daytime, the catfish were mainly inactive in the bottom layer. These behaviors contrast with what is documented in conspecifics from the core distribution area, perhaps reflecting adaptive strategies to cope with lower temperatures and shorter summers.
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| 3. |
- Engstedt, Olof, 1980-, et al.
(author)
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Annual spawning migration of anadromous pike (Esox lucius L.) in streams entering the Baltic Sea
-
Other publication (other academic/artistic)abstract
- The movement of pike (n = 3415) was investigated in four streams entering the Baltic Sea in the Kalmar Sound region, Sweden. Migration patterns were monitored during spawning in three of the streams and during the whole year in the forth stream using passive integrated transponders and outer tags. The study was conducted yearly between 2006 and 2010. Mature pike returned (22 – 45%) to the same streams year after year and some fish returned to the same regions of the streams. No incidence of fish visiting another stream than the one where they were marked was recorded and no fish missed the spawning season to return the next year. These results indicated that the reason for fish not returning was due to mortality. The proportions of returning fish indicated homing and the spawning ground fidelity (stream) was high. Return rates were influenced by size of fish, sex and stream identity. We also investigated if sex, size or individual behaviour influenced timing of arrival, departure or duration of stay in freshwater. Diurnal activity was examined in one year in each stream suggesting activity peaks in the morning and evening. The results show that pike in the Baltic Sea are anadromous and that the migration behavior is likely to create barriers for gene flow. The separation in populations by spawning are similar to salmonid species and the management of pike in the Baltic Sea must consider this process in strategies and plans of fishing.
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| 4. |
- Engstedt, Olof, 1980-, et al.
(author)
-
Experimental validation of Sr uptake in juvenile pike (Esox Lucius L.) otoliths – from water and food.
-
Other publication (other academic/artistic)abstract
- Strontium (Sr) or Sr:Ca ratios in otoliths have been widely used in the last decade to describe migration histories of fish between fresh and marine waters. However, reference experimental studies on particular species and waters are necessary to confirm the underlying assumption and evaluate the usefulness of this tool for field data. We conducted an experiment with the aim to answer these questions for anadromous pike (Esox lucius L.) in the Baltic Sea. Juvenile pike were reared in successively increasing salinities (10 steps from 0 to 7 ‰) for 110 days, and then in constant maximum salinity (7 ‰) for an additional 50 days. Pikes in the experiment were divided into two food treatments, given prey fish from brackish environments (7 ‰) and fish from freshwater lakes. Sr:Ca in pike otoliths were positively related to Sr in water (i.e salinity) in both treatments, suggesting that Sr:Ca ratios may be used to describe migration histories between rivers and the Baltic Sea. A significant difference in Sr.Ca ratios was found between the food treatments, showing that differences in diet may contribute to variation in otolith Sr:Ca, at least for pike in the Baltic Sea. Maximum Sr:Ca values for pike given marine food corresponded with field collected fish from the Baltic Sea.
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| 5. |
- Engstedt, Olof, 1980-, et al.
(author)
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Strontium (Sr) uptake from water and food in otoliths of juvenile pike (Esox lucius L.)
- 2012
-
In: Journal of Experimental Marine Biology and Ecology. - : Elsevier. - 0022-0981 .- 1879-1697. ; 418-419, s. 69-74
-
Journal article (peer-reviewed)abstract
- The strontium (Sr) or Sr:Ca ratio in otoliths has been widely used in the last decade to describe the migration histories of fish between fresh and marine waters. However, reference experimental studies of particular species and waters are necessary to confirm the underlying assumptions and evaluate the applicability of this tool to field data. Laboratory experiments indicated that juvenile, anadromous pike (Esox lucius L) from the Baltic Sea reared in successively increasing salinities (from 0 to 7 parts per thousand) for 110 d accumulated Sr in their otoliths according to a positive relationship with waterborne Sr. When the pike were given prey fish from brackish (7 parts per thousand) environments, the otolith Sr:Ca ratio increased more than in fish given prey from freshwater lakes. Pike held at constant salinity (7 parts per thousand) and given prey fish from the same salinity environment had an Sr:Ca ratio of 6.9 x 10(-3). The ratio decreased successively for fish given prey from freshwater (4.4 x 10(-3)) or kept in freshwater and given food from brackish water (3.1 x 10(-3)). Fish exposed to freshwater and given prey fish from freshwater displayed no increase in Sr:Ca ratio (1.6 x 10(-3)). The experiments demonstrated that the Sr:Ca ratio may be used to describe the migration history of pike between rivers and the Baltic Sea. The maximum Sr:Ca value for pike given marine-origin food corresponded to those of fish collected from the Baltic Sea.
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| 6. |
- Hall, Marcus, et al.
(author)
-
Reproductive homing and fine-scaled genetic structuring of anadromous Baltic Sea perch (Perca fluviatilis)
- 2022
-
In: Fisheries Management and Ecology. - : John Wiley & Sons. - 0969-997X .- 1365-2400. ; 29:5, s. 586-596
-
Journal article (peer-reviewed)abstract
- To investigate the population dynamics of anadromous Baltic Sea perch Perca fluviatilis (Linnaeus), we studied the migratory behaviour (arrival to spawning location) and population structure (genetic structure and differentiation) of three closely located (<50 km) populations. Spawning migration lasted for 32-80 days, and passive integrated transponder tag (PIT-tag) data indicated that anadromous perch displayed reproductive homing. Populations were differentiated, despite low levels of gene flow (3%-5%), and differentiation increased with increasing geographic distance. This fine-scaled spatial structuring was likely, at least partly, explained by homing behaviour. Analyses of temporal within-stream substructuring yielded inconclusive results, so further studies are required to evaluate this. Taken together, our findings highlight the potential for fine-scaled genetic structuring in anadromous perch and indicate that multiple mechanisms, such as isolation by distance, homing, and reproductive timing could contribute to this pattern. This illustrates the importance of considering cryptic barriers to accurately identify reproductive units, and points to the need for local management of anadromous perch.
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| 7. |
- Nordahl, Oscar, et al.
(author)
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Genetic differentiation between and within ecotypes of pike (Esox lucius) in the Baltic Sea
- 2019
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In: Aquatic conservation. - : John Wiley & Sons. - 1052-7613 .- 1099-0755. ; 29:11, s. 1923-1935
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Journal article (peer-reviewed)abstract
- Aquatic systems often lack physical boundaries for gene flow, but ecological and behavioural barriers can form surprisingly fine spatial scale genetic patterns that challenge traditional, large scale management. To detect fine spatial scale structures, understand sources of intraspecific diversity, and design appropriate management plans requires identification of reproductively isolated units. This study reports on genetic differentiation in pike (Esox lucius) within a coastal area stretching 55 km from south to north in the central Baltic Sea. Pike is here an economically and ecologically important top predator that has declined in abundance. However, population structures have mostly been studied on large spatial scales, and without considering the potential for genetic divergence between the sympatric anadromous fresh water and the resident brackish water spawning ecotypes. To this end, 487 individuals from the east coast of Sweden and the island of oland, representing sympatric anadromous and resident spawning individuals, categorized to ecotype based on spawning location or otolith microchemistry, were genotyped for 10 microsatellites and used to test for divergence between ecotypes. Furthermore, divergence between regions (island/mainland), neighbouring spawning locations (n = 13) and isolation by distance within and between regions were evaluated for the anadromous ecotype. The results revealed strong genetic differences between regions, between spawning locations separated by as little as 5 km and the first evidence of genetic differentiation between resident and anadromous ecotypes; despite a high dispersal capacity of pike and a high connectivity within the study area. The signatures of isolation by distance indicated that connectivity among populations differed between regions, probably reflecting availability of spawning habitats. To safeguard against the challenges and uncertainties associated with environmental change, adaptive conservation management should aim to promote high intra-population functional genetic diversity without compromising the continued integrity and coexistence of the different ecotypes and of locally adapted sub-populations.
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| 8. |
- Nordahl, Oscar, et al.
(author)
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Sun-basking fish benefit from body temperatures that are higher than ambient water
- 2018
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In: Proceedings of the Royal Society of London. Biological Sciences. - London : The Royal Society. - 0962-8452 .- 1471-2954. ; 285:1879
-
Journal article (peer-reviewed)abstract
- In terrestrial environments, cold-blooded animals can attain higher bodytemperatures by sun basking, and thereby potentially benefit from broaderniches, improved performance and higher fitness. The higher heat capacityand thermal conductivity of water compared with air have been universallyassumed to render heat gain from sun basking impossible for aquaticectotherms, such that their opportunities to behaviourally regulate body temperatureare largely limited to choosing warmer or colder habitats. Here wechallenge this paradigm. Using physical modelswe first showthat submergedobjects exposed to natural sunlight attain temperatures in excess of ambientwater. We next demonstrate that free-ranging carp (Cyprinus carpio) canincrease their body temperature during aquatic sun basking close to thesurface. The temperature excess gained by basking was larger in dark thanin pale individuals, increased with behavioural boldness, and was associatedwith faster growth. Overall, our results establish aquatic sun basking as a novelecologically significant mechanism for thermoregulation in fish. The discoveryof this previously overlooked process has practical implications for aquaculture,offers alternative explanations for behavioural and phenotypicadaptations, will spur future research in fish ecology, and calls for modificationsof models concerning climate change impacts on biodiversity inmarine and freshwater environments.
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| 9. |
- Nordahl, Oscar, et al.
(author)
-
Vertical movements of coastal pike (Esox lucius) : on the role of sun basking
- 2020
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In: Ecology of Freshwater Fish. - : John Wiley & Sons. - 0906-6691 .- 1600-0633. ; 29:1, s. 18-30
-
Journal article (peer-reviewed)abstract
- Knowledge of patterns and drivers of the spatiotemporal distribution of top predatory fish is key to understand ecological dynamics and to successful management. Here, we integrated field and laboratory approaches to study vertical movements of pike (Esox lucius) in relation to season, light regimes and body temperature. We tagged pike from the Baltic Sea with data storage tags during spawning migration and retrieved them during migration the following years to obtain high‐resolution data from full year of movements. The results showed seasonal and diel patterns of activity and body temperature that conformed to distinct patterns of crepuscular activity and diel vertical migrations. The latter manifested as two different patterns, either a stationary phase in the surface water during day followed by night‐time in deeper water or vice versa. The occurrence of these two behaviours varied among individuals and within individuals among seasons. Diel vertical migration has previously not been described for this shallow‐dwelling species, but was a common and consistent behaviour among individuals in this study. We suggest that the function of the daytime surface behaviour in pike is to increase body temperature through sun basking. This thermoregulatory role of surfacing was supported by the laboratory study where individuals sought the surface layer, exposed themselves to infrared light and thereby attained body temperatures in excess of ambient water. These results support sun basking as a mechanism for heat gain and further suggest that access to sunlight in the surface layer could be an important driver of vertical migrations.
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| 10. |
- Tibblin, Petter, et al.
(author)
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Effects of salinity on growth and mortality of migratory and resident forms of Eurasian perch in the Baltic Sea
- 2012
-
In: Ecology of Freshwater Fish. - : Wiley. - 0906-6691 .- 1600-0633. ; 21:2, s. 200-206
-
Journal article (peer-reviewed)abstract
- In the coastal areas of the Baltic Sea, there are two forms of perch (Perca fluviatilis). One of the forms is migratory and spawns instreams entering the Baltic Sea. The other form is resident and spawns in brackish water. Both forms utilise the coastal habitat for foraging. We examined the spawning success of the two forms in fresh and brackish water (7 parts per thousand, equal to salinity in thesouth Baltic Sea). The experiments showed that hatching success was equally high in freshwater and in brackish water despite female origin. The survival of yellow-sac and free swimming fry was significantly reduced in brackish water, which was independent if the fish wasof migratory or brackish resident origin. Further, growth rate of perch fry was severely reduced in brackish water. The results indicate thatperch has not developed any tolerance to brackish water in the young life stages. The migratory life strategy of perch can thus be explained by higher survival of fry in freshwater.
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| 11. |
- Berggren, Hanna
(author)
-
Consequences of Environmental Variation for Fish and Their Skin Associated Microbial Communities
- 2021
-
Doctoral thesis (other academic/artistic)abstract
- Environmental conditions that vary in space and time influence the distribution, abundance, diversity and evolution of individuals, populations, species and communities. This thesis explores how environmental variation affects diversity at different levels of biological organization, and across a wide range of spatiotemporal scales, by studying fish and their associated microbiomes. The specific aims were to investigate i) effects of coarse- and fine-scale environmental variation for the performance of fish populations and individuals, and ii) ecological drivers impacting the structure and dynamics of microbial communities associated with fish hosts.For the first aim, I studied effects of environmental variation both within and between local habitats, by comparing populations of spawning migrating pike and monitor sun-basking behaviour of carp individuals. Results revealed that natal spawning site fidelity can promote evolution of local adaptations and population differentiation on relatively fine spatial scales in relation to the species dispersal capacity. I also demonstrated that fish can actively thermo-regulate and attain body temperatures in excess of the surrounding water by sun-basking, and that this translates into faster growth. Homing and sun-basking behaviour thus are important drivers of phenotypic diversity among and within populations and can also - as it turned out - influence the microbial communities associated with fish skin.For the second aim, I used a mixture of observational and experimental approaches to characterize and identify sources of variation in microbial communities associated with fish skin of perch, roach and carp. An important finding was that fish skin microbiomes are highly dynamic biodiversity hotspots. Results further suggested that variation in the assembly, composition, spatial structure, and temporal shifts of these microbiomes are influenced by stochastic events in combination with ecological filtering imposed by environment and host phenotype, most notably behaviour. A key conclusion that emerges from this thesis is that diversity at one level of biological organisation seems to support and increase diversity at a higher hierarchical level of organisation. My thesis thus adds to the knowledge, and contribute new understanding and insight into, how environmental heterogeneity and the complex interplay between different species and hierarchical levels generate and maintain biodiversity.
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| 12. |
- Berggren, Hanna, et al.
(author)
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Effects of environmental translocation and host characteristics on skin microbiomes of sun-basking fish
- 2023
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In: Proceedings of the Royal Society of London. Biological Sciences. - : Royal Society. - 0962-8452 .- 1471-2954. ; 290:2013
-
Journal article (peer-reviewed)abstract
- Variation in the composition of skin-associated microbiomes has been attributed to host species, geographical location and habitat, but the role of intraspecific phenotypic variation among host individuals remains elusive. We explored if and how host environment and different phenotypic traits were associated with microbiome composition. We conducted repeated sampling of dorsal and ventral skin microbiomes of carp individuals (Cyprinus carpio) before and after translocation from laboratory conditions to a semi-natural environment. Both alpha and beta diversity of skin-associated microbiomes increased substantially within and among individuals following translocation, particularly on dorsal body sites. The variation in microbiome composition among hosts was significantly associated with body site, sun-basking, habitat switch and growth, but not temperature gain while basking, sex, personality nor colour morph. We suggest that the overall increase in the alpha and beta diversity estimates among hosts were induced by individuals expressing greater variation in behaviours and thus exposure to potential colonizers in the pond environment compared with the laboratory. Our results exemplify how biological diversity at one level of organization (phenotypic variation among and within fish host individuals) together with the external environment impacts biological diversity at a higher hierarchical level of organization (richness and composition of fish-associated microbial communities).
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| 13. |
- Berggren, Hanna, et al.
(author)
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Fish skin microbiomes are highly variable among individuals and populations but not within individuals
- 2022
-
In: Frontiers in Microbiology. - : Frontiers Media S.A.. - 1664-302X. ; 12
-
Journal article (peer-reviewed)abstract
- Fish skin-associated microbial communities are highly variable among populations and species and can impact host fitness. Still, the sources of variation in microbiome composition, and particularly how they vary among and within host individuals, have rarely been investigated. To tackle this issue, we explored patterns of variation in fish skin microbiomes across different spatial scales. We conducted replicate sampling of dorsal and ventral body sites of perch (Perca fluviatilis) from two populations and characterized the variation of fish skin-associated microbial communities with 16S rRNA gene metabarcoding. Results showed a high similarity of microbiome samples taken from the left and right side of the same fish individuals, suggesting that fish skin microbiomes can be reliably assessed and characterized even using a single sample from a specific body site. The microbiome composition of fish skin differed markedly from the bacterioplankton communities in the surrounding water and was highly variable among individuals. No ASV was present in all samples, and the most prevalent phyla, Actinobacteria, Bacteroidetes, and Proteobacteria, varied in relative abundance among fish hosts. Microbiome composition was both individual- and population specific, with most of the variation explained by individual host. At the individual level, we found no diversification in microbiome composition between dorsal and ventral body sites, but the degree of intra-individual heterogeneity varied among individuals. To identify how genetic and phenotypic characteristics of fish hosts impact the rate and nature of intra-individual temporal dynamics of the skin microbiome, and thereby contribute to the host-specific patterns documented here, remains an important task for future research.
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| 14. |
- Bernes, Claes, et al.
(author)
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What is the influence on water quality in temperate eutrophic lakes of a reduction of planktivorous and benthivorous fish? : A systematic review protocol
- 2013
-
In: Environmental Evidence. - : BioMed Central (BMC). - 2047-2382. ; 2:1
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Research review (peer-reviewed)abstract
- Background: In lakes that have become eutrophic due to sewage discharges or nutrient runoff from land, problems such as algal blooms and oxygen deficiency often persist even when nutrient supplies have been reduced. One reason is that phosphorus stored in the sediments can exchange with the water. There are indications that the high abundance of phytoplankton, turbid water and lack of submerged vegetation seen in many eutrophic lakes may represent a semi-stable state. For that reason, a shift back to more natural clear-water conditions could be difficult to achieve. In some cases, though, temporary mitigation of eutrophication-related problems has been accomplished through biomanipulation: stocks of zooplanktivorous fish have been reduced by intensive fishing, leading to increased populations of phytoplankton-feeding zooplankton. Moreover, reduction of benthivorous fish may result in lower phosphorus fluxes from the sediments. An alternative to reducing the dominance of planktivores and benthivores by fishing is to stock lakes with piscivorous fish. These two approaches have often been used in combination. The implementation of the EU Water Framework Directive has recently led to more stringent demands for measures against eutrophication, and a systematic review could clarify whether biomanipulation is efficient as a measure of that kind. Methods: The review will examine primary field studies of how large-scale biomanipulation has affected water quality and community structure in eutrophic lakes or reservoirs in temperate regions. Such studies can be based on comparison between conditions before and after manipulation, on comparison between treated and nontreated water bodies, or both. Relevant outcomes include Secchi depth, concentrations of oxygen, nutrients, suspended solids and chlorophyll, abundance and composition of phytoplankton, zooplankton and fish, and coverage of submerged macrophytes.
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| 15. |
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| 16. |
- De Rosa, Maria, et al.
(author)
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Design, synthesis and in vitro biological evaluation of oligopeptides targeting E. coli type I signal peptidase (LepB)
- 2017
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In: Bioorganic & Medicinal Chemistry. - : Elsevier BV. - 0968-0896 .- 1464-3391. ; 25:3, s. 897-911
-
Journal article (peer-reviewed)abstract
- Type I signal peptidases are potential targets for the development of new antibacterial agents. Here we report finding potent inhibitors of E. coli type I signal peptidase (LepB), by optimizing a previously reported hit compound, decanoyl-PTANA-CHO, through modifications at the N- and C-termini. Good improvements of inhibitory potency were obtained, with IC50s in the low nanomolar range. The best inhibitors also showed good antimicrobial activity, with MICs in the low μg/mL range for several bacterial species. The selection of resistant mutants provided strong support for LepB as the target of these compounds. The cytotoxicity and hemolytic profiles of these compounds are not optimal but the finding that minor structural changes cause the large effects on these properties suggests that there is potential for optimization in future studies.
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| 17. |
- Engstedt, Olof, et al.
(author)
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Assessment of natal origin of pike (Esox lucius) in the Baltic Sea using Sr:Ca in otoliths
- 2010
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In: Environmental Biology Of Fishes. - : Springer Science and Business Media LLC. - 0378-1909 .- 1573-5133. ; 89:3-4, s. 547-555
-
Conference paper (peer-reviewed)abstract
- Spawning habitat of pike (Esox lucius) in the Baltic Sea include brackish water bays, brooks and rivers. Elevated salinity concentrations are one of several stressors that might increase the use and importance of freshwater habitats for spawning. In the Baltic Sea, one of the largest brackish seas in the world, freshwater species like pike, perch (Perca fluviatilis), whitefish (Coregonus sp), bream (Abramis brama), ide (Leuciscus idus), roach (Rutilus rutilus) and burbot (Lola iota) all undertake spawning migrations to freshwater. However, over the last decades populations densities of these species have declined, and recruitment failure has been argued to be at least part of the problem. The importance of brooks and rivers as spawning areas for these species have not been quantified and set in relation to spawning success in brackish bays. In this study, we collected 175 adult pike (Esox lucius) on their foraging grounds in the sea. Fish were collected in two regions on the Baltic coast, more than 600 km apart. Subsequently we determined their origin (freshwater or marine) using otolith chemistry. Sagittal otoliths were analysed for strontium using the PIXE-method. The results show that 80 of the 175 pike were recruited in freshwater, and several of the larger specimens showed reoccurring migration behaviour. Data show that freshwater is an important recruitment habitat for Baltic Sea pike, suggesting that habitat improvements in rivers entering the Baltic Sea might significantly contribute to population restoration.
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| 18. |
- Engstedt, Olof, 1980-, et al.
(author)
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Elemental fingerprinting in otoliths reveals natal homing of anadromous Baltic Sea pike (Esox lucius L.)
-
Other publication (other academic/artistic)abstract
- Northern pike (Esox lucius) inhabit the coastal areas of the Baltic Sea. A large part of the fishes show anadromous behaviour and spawn in streams and rivers but spend most of the time foraging in the sea. We examined spawning migration in four streams in the southwest part of the Baltic, situated within a radius of 50 km. Using juvenile pike in the streams as references, otolith analysis by microPIXE revealed unique elemental patterns (Sr, Zn, Br, Co and Mn) for the juveniles in each of the four different streams. The strontium signal in the otolith of the juveniles was used as an indicator of freshwater origin and the time spent in the stream (size of juveniles). Adult marked pike in their migrating spawning phase were caught in each of the streams and otoliths were analysed. Defining earlier freshwater origin by the Sr signal from the otolith core to the increase in Sr when the fish as juvenile pike migrated to the sea, element composition was determined. A principal component analysis showed that the elemental fingerprint during the freshwater phase several years back was similar for adult fish and juveniles inhabiting the stream today. The results indicated native homing of the adults to a specific stream, a process further corroborated by results from electronic marking (Pit-tags) with the return of adult individuals over several consecutive years. We interpret the results as evidence that pike in the Baltic Sea consists of several sub-populations and are developed by homing to specific spawning streams. The results of the study may have implications for fishery management as pike in the Baltic Sea cannot be seen as homogenous “stock“, but instead consists of different, unique populations similar to the pattern demonstrated in salmon (Salmo salar).
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| 19. |
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| 20. |
- Flink, Henrik, et al.
(author)
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Examining the effects of authentic C&R on the reproductive potential of Northern pike
- 2021
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In: Fisheries Research. - : Elsevier. - 0165-7836 .- 1872-6763. ; 243
-
Journal article (peer-reviewed)abstract
- The practice within recreational fisheries to release captured fish back to the wild, known as catch-and-release (C&R), is an increasingly important strategy to protect fish stocks from overexploitation. However, C&R is a stressor and since animal reproduction is particularly sensitive to stress there is reason to suspect that such a practice induces sublethal fitness consequences. Here, we investigated whether and how C&R fishing influenced the reproductive potential in an anadromous population of Northern pike (Esox lucius). First, female pike were exposed to authentic C&R using rod-and-reel fishing in a coastal foraging habitat prior to the spawning period. Next, we observed the migration to the freshwater spawning habitat and compared both the timing of arrival and maturity stage between C&R-treated and control individuals. Finally, to evaluate effects on the quality and viability of eggs we stripped captured control and recaptured C&R-treated females, measured egg dry mass to assess nutrient content, conducted artificial fertilisations and incubated eggs in a controlled laboratory experiment. We found no evidence of C&R causing alterations in either arrival time, maturity stage, or the quality and viability of fertilised eggs. In combination, our results suggest that long-term effects of C&R-induced stress on key reproductive traits of pike, if any, are minor.
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| 21. |
- Fridolfsson, Emil, et al.
(author)
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Förstudie kring hållbar vattenförsörjning i södra Sverige
- 2021
-
Reports (pop. science, debate, etc.)abstract
- Dricksvatten är vårt viktigaste livsmedel men detta rena vatten används även för bevattningsändamål, i vårt avloppssystem och inom industrin. Våra samlade vattenresurser ger dessutom ekosystemtjänster i form av fiske, rekreationsvärde m.m. (Bergek m. fl., 2017). Trots att Sverige är ett mycket vattenrikt land sett ur ett internationellt perspektiv har vattenbrist uppstått i flera delar av landet under senare år. Vidare förväntas pågående och kommande klimatförändringar, befolkningstillväxt och urbanisering påverka vattenkvaliteten negativt samt öka konkurrensen om vatten ytterligare (IPCC, 2014; SMHI, 2020a). Med ökad konkurrens uppstår dessutom målkonflikter mellan olika viktiga samhällsfunktioner. Det finns således ett stort behov av tvärsektoriell forskning samt policyutveckling för att säkerställa en hållbar framtida vattenförsörjning.Denna rapport syftar till att sammanställa kunskapsläget vad gäller förutsättningarna för en hållbar vattenförsörjning i Kronobergs län. Först beskrivs tillgång och uttag av dricksvatten i Kronoberg i jämförelse med Kalmar och Skåne län samt förutsättningarna för god framtida vattenkvalitet med Bolmen som exempel. Därefter fokuserar vi på de målkonflikter som kan förväntas uppstå kring dricksvattnet och diskuterar slutligen de kunskapsluckor samt det behov av tvärsektoriell forskning och samhällsutveckling som behövs för en hållbar vattenförsörjning.
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| 22. |
- Glise, Lars, 1988, et al.
(author)
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Disturbed Laminar Blood Flow Causes Impaired Fibrinolysis and Endothelial Fibrin Deposition In Vivo
- 2019
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In: Thrombosis and Haemostasis. - : Georg Thieme Verlag KG. - 0340-6245 .- 2567-689X. ; 119:2, s. 223-233
-
Journal article (peer-reviewed)abstract
- Endothelial expression of tissue-type plasminogen activator (t-PA) is crucial for maintaining an adequate endogenous fibrinolysis. It is unknown how endothelial t-PA expression and fibrinolysis are affected by blood flow in vivo. In this study, we investigated the impact of different blood flow profiles on endothelial t-PA expression and fibrinolysis in the arterial vasculature. Induction of disturbed laminar blood flow (D-flow) in the mouse carotid artery potently reduced endothelial t-PA messenger ribonucleic acid and protein expression, and caused fibrin deposition. En face immunohistochemistry demonstrated that arterial areas naturally exposed to D-flow had markedly lower endothelial t-PA levels than areas with sustained laminar blood flow (S-flow), and displayed pronounced fibrin deposition despite an intact endothelium. In t-PA and plasminogen-deficient mice, fibrin deposition did not extend into S-flow areas, indicating that areas of D-flow and S-flow differ, not only in fibrinolytic capacity, but also in coagulation. Furthermore, plasminogen accumulation was found at D-flow areas, and infusion of recombinant t-PA activated fibrinolysis and significantly reduced the fibrin deposits. In conclusion, D-flow potently impairs the fibrinolytic capacity and causes endothelial fibrin deposition in vivo. Our data also indicate that t-PA is the limiting factor for efficient fibrinolysis at the thrombosis-prone D-flow areas in the arterial vasculature.
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| 23. |
- Hall, Marcus, et al.
(author)
-
Intra-population variation in reproductive timing covaries with thermal plasticity of offspring performance in perch Perca fluviatilis
- 2021
-
In: Journal of Animal Ecology. - : John Wiley & Sons. - 0021-8790 .- 1365-2656.
-
Journal article (peer-reviewed)abstract
- Life history theory posits that organisms should time their reproduction to coincide with environmental conditions that maximize their fitness. Population-level comparisons have contributed important insights on the adaptive value of reproductive timing and its association to environmental variation. Yet, despite its central role to ecology and evolution, the causes and consequences of variation in reproductive timing among individuals within populations are poorly understood in vertebrates other than birds.Using a combination of observational field studies and a split-brood experiment, we investigated whether differences in breeding time were associated with changes in hatching success, reproductive allocation and reaction norms linking offspring performance to temperature within an anadromous Baltic Sea population of perch Perca fluviatilis.Field observations revealed substantial variation in reproductive timing, with the breeding period lasting almost 2 months and occurring in temperatures ranging from 10 to 21°C. The hatching success of perch decreased as the reproductive season progressed. At the same time, the reproductive allocation strategy changed over the season, late breeders (the offspring of which were introduced into a high resource environment and increased predation pressure) produced more and smaller eggs that resulted in smaller larvae, compared with early breeders.The split-brood experiment in which eggs were incubated in different temperatures (10, 12, 15, 18°C) showed that differences in reproductive timing were associated with a change in the shape of the reaction norm linking offspring performance to water temperature indicative of adaptive phenotypic plasticity, with the offspring of early breeders performing best in low temperatures and the offspring of late breeders performing best in high temperatures.The seasonal changes in reproductive traits and the shape of the thermal performance suggest time-dependent adaptive differences among individuals within the population. Management actions aimed at preserving and restoring variation in the timing of reproductive events will thus likely also influence variation in associated life history traits and thermal performance curves, which could safeguard populations against environmental challenges and changes associated with exploitation and global warming.
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| 24. |
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| 25. |
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| 26. |
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| 27. |
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| 28. |
- Jensen, Axel, et al.
(author)
-
Whole genome sequencing reveals high differentiation, low levels of genetic diversity and short runs of homozygosity among Swedish wels catfish
- 2021
-
In: Heredity. - : Nature Publishing Group. - 0018-067X .- 1365-2540. ; 127, s. 79-91
-
Journal article (peer-reviewed)abstract
- The use of genetic markers in the context of conservation is largely being outcompeted by whole-genome data. Comparative studies between the two are sparse, and the knowledge about potential effects of this methodology shift is limited. Here, we used whole-genome sequencing data to assess the genetic status of peripheral populations of the wels catfish (Silurus glanis), and discuss the results in light of a recent microsatellite study of the same populations. The Swedish populations of the wels catfish have suffered from severe declines during the last centuries and persists in only a few isolated water systems. Fragmented populations generally are at greater risk of extinction, for example due to loss of genetic diversity, and may thus require conservation actions. We sequenced individuals from the three remaining native populations (Baven, Eman, and Mockeln) and one reintroduced population of admixed origin (Helge a), and found that genetic diversity was highest in Eman but low overall, with strong differentiation among the populations. No signature of recent inbreeding was found, but a considerable number of short runs of homozygosity were present in all populations, likely linked to historically small population sizes and bottleneck events. Genetic substructure within any of the native populations was at best weak. Individuals from the admixed population Helge a shared most genetic ancestry with the Baven population (72%). Our results are largely in agreement with the microsatellite study, and stresses the need to protect these isolated populations at the northern edge of the distribution of the species.
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| 29. |
- Larsson, Bengt, et al.
(author)
-
Molecular oxygen in the rho Ophiuchi cloud
- 2007
-
In: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 466:3, s. 5-
-
Journal article (peer-reviewed)abstract
- Context: Molecular oxygen, O2, has been expected historically to be an abundant component of the chemical species in molecular clouds and, as such, an important coolant of the dense interstellar medium. However, a number of attempts from both ground and from space have failed to detect O2 emission.Aims: The work described here uses heterodyne spectroscopy from space to search for molecular oxygen in the interstellar medium. Methods: The Odin satellite carries a 1.1 m sub-millimeter dish and a dedicated 119 GHz receiver for the ground state line of O2. Starting in 2002, the star forming molecular cloud core ρ Oph A was observed with Odin for 34 days during several observing runs.Results: We detect a spectral line at v_LSR =+3.5 km s-1 with Δ v_FWHM=1.5 km s-1, parameters which are also common to other species associated with ρ Oph A. This feature is identified as the O2 (NJ = 11 - 1_0) transition at 118 750.343 MHz.Conclusions: The abundance of molecular oxygen, relative to H{2} , is 5 × 10-8 averaged over the Odin beam. This abundance is consistently lower than previously reported upper limits.Based on observations with Odin, a Swedish-led satellite project funded jointly by the Swedish National Space Board (SNSB), the Canadian Space Agency (CSA), the National Technology Agency of Finland (Tekes) and Centre National d'Étude Spatiale (CNES). The Swedish Space Corporation has been the industrial prime contractor and also is operating the satellite. Appendix A is only available in electronic form at http://www.aanda.org
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| 30. |
- Larsson, Gerry, et al.
(author)
-
A Comprehensive system for leader evaluation and development
- 2002
-
In: The Leadership & Organization Development Journal. - 0143-7739. ; 24:1, s. 16-25
-
Journal article (peer-reviewed)abstract
- The aim was to describe the development of a theoretical model for leader evaluation and development, an instrument based on this model, and a strategy for large scale implementation in the Swedish armed forces. The model rests on an interactional person by situation paradigm. It emphasises "developmental leadership", which is inspired by transformational and functionalistic leadership approaches. The developmental leadership questionnaire (DLQ) was operationalised from the model and refined through structural equation modelling. The model and the DLQ will be used for three purposes: yearly evaluation of all personnel in the Swedish armed forces; yearly planning dialogues between each employee and his or her nearest supervisor; and a tool for leadership training. The implementation strategy includes an initial course in developmental leadership for all colonels. This is followed by the selection and training of local trainers, who, in turn, initiate the comprehensive programme locally. The system should be fully implemented by 2005.
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| 31. |
- Larsson, Johanna, et al.
(author)
-
Bacterial contamination of suction catheter tips during aortic valve replacement surgery: a prospective observational cohort study.
- 2015
-
In: Patient safety in surgery. - : Springer Science and Business Media LLC. - 1754-9493. ; 9
-
Journal article (peer-reviewed)abstract
- Bacterial mediastinitis is a severe complication after open heart surgery. The infection causes prolonged hospitalization and an increased mortality risk. Observations from orthopaedic surgery showed that the suction catheter used during surgery is commonly contaminated with bacteria. The aim of this study was to describe the prevalence of suction catheter contamination in cardiac surgery and to study if suction time influences the contamination risk.
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| 32. |
- Larsson, Jörgen, 1954-, et al.
(author)
-
Bältesanvändning i Sverige 2013
- 2014
-
Reports (other academic/artistic)abstract
- VTI har observerat bilbältesanvändningen i ett antal syd- och mellansvenska städer sedan 1983. Observationerna år 2013 gjordes under sammanlagt ett tiotal dagar i augusti–september. Sammanlagt observerades drygt 58 400 personbilar, drygt 1 200 taxibilar samt cirka 8 700 övriga bilar, exempelvis lastbilar. Bilbältesanvändningen bland förare och framsätespassagerare i personbil har under hela observationsperioden 1983–2013 legat på en betydligt högre och jämnare nivå än bland baksätespassagerare. Redan i mätseriens början använde 84–86 procent av förare och framsätespassagerare bälte. År 2013 är nivåerna på 97–98 procent. När VTI:s mätserie började 1983 var bältesanvändningen bland vuxna i baksätet endast 10 procent. Den ökade i ett steg till 60 procent när lagen om bilbältesanvändning för vuxna i hela bilen trädde i kraft 1 juli 1986. Enligt de senaste observationerna är cirka 84 procent av alla vuxna baksätespassagerare bältade, vilket är lägre än nivån år 2012. I baksätet har barnen alltid haft en betydligt högre bältesanvändning än de vuxna, vilket gäller även 2013 då drygt 96 procent av barnen i baksätet var bältade. Bältesanvändningen bland barn i baksätet är således fortfarande i paritet med den bland förare och passagerare i framsätet. Från och med 1994 års observationer ingår också ett delprojekt där förarnas bältesanvändning kopplas till förarnas kön och ålder.
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| 33. |
- Larsson, Jörgen, 1954-, et al.
(author)
-
Bältesanvändning i Sverige 2014
- 2015
-
Reports (other academic/artistic)abstract
- VTI har observerat bilbältesanvändningen i ett antal syd- och mellansvenska städer sedan 1983. Bilbältesanvändningen för passagerare i både fram- och baksäte ökade fram till 2012, därefter har ökningen upphört. Bland yrkesförare har bältesanvändningen däremot ökat kontinuerligt. Observationerna år 2014 gjordes under ett tiotal dagar i augusti–september. Sammanlagt observerades drygt 57 200 personbilar, nästan 1 300 taxibilar samt cirka 9 700 övriga bilar, exempelvis lastbilar. Bilbältesanvändningen i framsätet av personbil ligger på 96-97 procent för 2014, vilket är en liten minskning jämfört med året innan. När VTI:s mätserie började 1983 var bältesanvändningen bland vuxna i baksätet endast 10 procent. Enligt de senaste observationerna är cirka 81 procent av alla vuxna baksätespassagerare bältade, vilket är tre procentenheter lägre än nivån år 2013.
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| 34. |
- Larsson, Jörgen, 1954-, et al.
(author)
-
Bältesanvändning i Sverige 2015
- 2016
-
Reports (other academic/artistic)abstract
- Detta notat redovisar resultatet av VTI:s årliga mätning av bilbältesanvändning som genomförts i ett antal syd- och mellansvenska städer sedan 1983. Redan i mätseriens början använde 84–86 procent av förare och framsätespassagerare bälte. År 2015 är nivåerna på 97–98 procent, en liten uppgång jämfört med föregående år. 1983 var bältesanvändningen bland vuxna i baksätet endast 10 procent.Enligt de senaste observationerna är 89 procent av alla vuxna baksätespassagerare bältade, vilket är den hittills högsta noteringen och en betydligt högre nivå än 2014. I baksätet har barnen alltid haft en betydligt högre bältesanvändning än de vuxna, vilket gäller även 2015 då 97 procent av barnen i baksätet var bältade. Detta är en uppgång jämfört med 2014, och bältesnyttjandet bland barn i baksätet är i paritet med den bland förare och passagerare i framsätet.En delstudie bland personbilsförarna visar att kvinnor genomgående har högre bältesanvändning än män. Dessutom gäller att bältesanvändningen ökar med ökad ålder, särskilt bland manliga personbilsförare. De yngsta (18–25 år) manliga personbilsförarna har den lägsta bältesanvändningen.
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| 35. |
- Larsson, Pia, 1978, et al.
(author)
-
Role of histone acetylation in the stimulatory effect of valproic acid on vascular endothelial tissue-type plasminogen activator expression
- 2012
-
In: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 7:2
-
Journal article (peer-reviewed)abstract
- AIMS: Stimulated release of tissue-type plasminogen activator (t-PA) is pivotal for an intravascular fibrinolytic response and protects the circulation from occluding thrombosis. Hence, an impaired t-PA production is associated with increased risk for atherothrombotic events. A pharmacological means to stimulate the production of this enzyme may thus be desirable. We investigated if the anti-epileptic drug valproic acid (VPA) is capable of enhancing t-PA expression in vitro in vascular endothelial cells, and further examined if its histone deacetylase (HDAC)-inhibitory activity is of importance for regulating t-PA expression. METHODS AND RESULTS: Human endothelial cells were exposed to valproic acid and t-PA mRNA and protein levels were quantified. Potential changes in histone acetylation status globally and at the t-PA promoter were examined by western blot and chromatin immunoprecipitation. Valproic acid dose-dependently stimulated t-PA mRNA and protein expression in endothelial cells reaching a 2-4-fold increase at clinically relevant concentrations and 10-fold increase at maximal concentrations. Transcription profiling analysis revealed that t-PA is selectively targeted by this agent. Augmented histone acetylation was detected at the t-PA transcription start site, and an attenuated VPA-response was observed with siRNA knock of HDAC3, HDAC5 and HDAC7. CONCLUSIONS: Valproic acid induces t-PA expression in cultured endothelial cells, and this is associated with increased histone acetylation at the t-PA promoter. Given the apparent potency of valproic acid in stimulating t-PA expression in vitro this substance may be a candidate for pharmacological modulation of endogenous fibrinolysis in man.
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| 36. |
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| 37. |
- Ljungqvist, Olle, 1954-, et al.
(author)
-
Food deprivation alters liver glycogen metabolism and endocrine responses to hemorrhage
- 1990
-
In: American Journal of Physiology. - : American Physiological Society. - 0002-9513 .- 2163-5773. ; 259:5 Part 1, s. E692-E698
-
Journal article (peer-reviewed)abstract
- Liver glycogen content, blood glucose, insulin, glucagon, and epinephrine were determined during 1 h hemorrhagic hypotension at 60 mmHg and 23 h thereafter in fed and two groups of 24-h food-deprived rats receiving either no infusion or 30% glucose intravenously during hemorrhage. Liver glycogen content was reduced by greater than 90% after 24-h food deprivation. Fed and food-deprived rats given glucose developed similar and substantial elevations of blood glucose during hemorrhage, whereas changes in blood glucose were modest in food-deprived rats given no infusion. In fed rats, liver glycogen was reduced by 60% during the 1-h bleed, but within 2 h after hemorrhage repletion of liver glycogen content commenced. By 6 h, approximately 75% of the glycogen lost during hemorrhage had been restored, and 23 h after hemorrhage liver glycogen content was six times greater compared with nonbled controls. Although glycogen levels increased after hemorrhage in food-deprived animals, the increase was negligible compared with that found in fed rats. Infusion of glucose during hemorrhage or adrenergic blockade after hemorrhage did not alter glycogen repletion in food-deprived rats. Posthemorrhage fed animals had high levels of insulin, glucagon, and epinephrine during hemorrhage, whereas insulin levels remained low in food-deprived rats despite exogenously induced hyperglycemia. It is concluded that rapid and substantial glycogen repletion can occur even immediately poststress. The conditions seem to be related to the nutritional state at the time of the insult.
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| 38. |
- Nilsson, Jonas, et al.
(author)
-
Wetlands for Northern Pike Recruitment and Nutrient Reduction
-
Other publication (other academic/artistic)abstract
- Wetlands are important ecosystems, harbouring biodiversity, capturing nutrients, and providing recruitment habitats for several fish species. The Baltic Sea, among the largest brackish, semi-enclosed seas in the world, is exposed to large amounts of nutrients as well as the overexploitation of several fish species. One measure to counteract eutrophication is to restore or build wetlands for nutrient catchment (phosphorus) or removal (nitrogen). To function optimally for nutrient removal, these wetlands should cover large areas, be shallow, and be covered by vegetation, creating zones of high microbial denitrification. Wetland environments are also suitable spawning and nursery areas for several fish species inhabiting the coastal zone of the Baltic Sea. Pike (Esox lucius) a predatory species that has decreased in abundance in recent decades, use wetlands as recruitment areas during their anadromous life cycle. After restoring wetlands near the coast and opening the waterways towards the sea, pike larval emigration increased from a few thousand to over a hundred thousand individuals. The habitat and food choice, growth and migration of larvae and juveniles were followed over time, revealing that 80–95% left the wetlands within one month (at a size <6 cm). An optimal wetland enriches nutrients and creates a high primary production base for zooplankton that are used as food for pike larvae. Wetlands near the sea can function both as nutrient traps and as recruitment areas for fish.
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| 39. |
- Nygren, Jonas, et al.
(author)
-
Preoperative gastric emptying : the effects of anxiety and carbohydrate administration
- 1995
-
In: Annals of Surgery. - : Lippincott Williams & Wilkins. - 0003-4932 .- 1528-1140. ; 222:6, s. 728-734
-
Journal article (peer-reviewed)abstract
- Background: Overnight fasting is routine before elective surgery. This may not be the optimal way to prepare for surgical stress, however, because intravenous carbohydrate supplementation instead of fasting has recently been shown to reduce postoperative insulin resistance. In the current study, gastric emptying of a carbohydrate-rich drink was investigated before elective surgery and in a control situation. Methods: Twelve patients scheduled for elective surgery were randomly given 400 mL of either a carbohydrate-rich drink (285 mOsm/kg, 12.0% carbohydrates, n = 6) or water 4 hours before being anesthetized. Gastric emptying was measured (gamma camera, 99Tcm). Each patient repeated the protocol postoperatively as a control. All values were presented as the mean ± SEM by means of a nonparametric statistical evaluation. Results: Despite the increased anxiety experienced by patients before surgery (p < 0.005), gastric emptying did not differ between the experimental and control situations. Initially, water emptied more rapidly than carbohydrate. However, after 90 minutes, the stomach was emptied regardless of the solution administered (3.2 ± 1.1% [mean ± SEM] remaining in the stomach in the carbohydrate group versus 2.3 ± 1.2% remaining in the stomach in the water group). Conclusions: Preoperative anxiety does not prolong gastric emptying. The stomach had been emptied 90 minutes after ingestion of both the carbohydrate-rich drink and water, thereby indicating the possibility of allowing an intake of iso-osmolar carbohydrate-rich fluids before surgery.
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| 40. |
- Ohlsson, Claes, 1965, et al.
(author)
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Increased weight loading reduces body weight and body fat in obese subjects – A proof of concept randomized clinical trial
- 2020
-
In: EClinicalMedicine. - : Elsevier BV. - 2589-5370. ; 22
-
Journal article (peer-reviewed)abstract
- Background: Recently we provided evidence for a leptin-independent homeostatic regulation, the gravitostat, of body weight in rodents. The aim of the present translational proof of concept study was to test the gravitostat hypothesis in humans. Methods: We conducted a randomized controlled single center trial (ClinicalTrial.gov number, NCT03672903), to evaluate the efficacy of artificially increased weight loading on body weight in subjects with mild obesity (BMI 30–35 kg/m2). Subjects were either treated with a heavy (=high load; 11% of body weight) or light (=low load; 1% of body weight) weight vest for eight hours per day for three weeks. The primary outcome was change in body weight. Secondary outcomes included change in body fat mass and fat-free mass as measured using bioelectrical impedance analysis. Findings: In total 72 participants underwent randomization and 69 (36 high load and 33 low load) completed the study for the primary outcome. High load treatment resulted in a more pronounced relative body weight loss compared to low load treatment (mean difference -1.37%, 95% confidence interval (CI), -1.96 to -0.79; p = 1.5 × 10−5). High load treatment reduced fat mass (-4.04%, 95% CI, -6,53 to -1.55; p = 1.9 × 10−3) but not fat free mass (0.43%, 95% CI, -1.47 to 2.34; p = 0.65) compared to low load treatment. Interpretation: Increased weight loading reduces body weight and fat mass in obese subjects in a similar way as previously shown in obese rodents. These findings demonstrate that there is weight loading dependent homeostatic regulation of body weight, the gravitostat, also in humans. Funding: Funded by Jane and Dan Olsson (JADO) Foundation, the Torsten Söderberg Foundation, The Knut and Alice Wallenberg's Foundation and the Novo Nordisk Foundation. © 2020 The Author(s)
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| 41. |
- Pandey, Gaurav Kumar, et al.
(author)
-
The risk-associated long noncoding RNA NBAT-1 controls neuroblastoma progression by regulating cell proliferation and neuronal differentiation.
- 2014
-
In: Cancer Cell. - : Elsevier BV. - 1535-6108 .- 1878-3686. ; 26:5, s. 722-737
-
Journal article (peer-reviewed)abstract
- Neuroblastoma is an embryonal tumor of the sympathetic nervous system and the most common extracranial tumor of childhood. By sequencing transcriptomes of low- and high-risk neuroblastomas, we detected differentially expressed annotated and nonannotated long noncoding RNAs (lncRNAs). We identified a lncRNA neuroblastoma associated transcript-1 (NBAT-1) as a biomarker significantly predicting clinical outcome of neuroblastoma. CpG methylation and a high-risk neuroblastoma associated SNP on chromosome 6p22 functionally contribute to NBAT-1 differential expression. Loss of NBAT-1 increases cellular proliferation and invasion. It controls these processes via epigenetic silencing of target genes. NBAT-1 loss affects neuronal differentiation through activation of the neuronal-specific transcription factor NRSF/REST. Thus, loss of NBAT-1 contributes to aggressive neuroblastoma by increasing proliferation and impairing differentiation of neuronal precursors.
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| 42. |
- Rydin, Emil, et al.
(author)
-
Remediation of a eutrophic bay in the Baltic Sea
- 2017
-
In: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 51:8, s. 4559-4566
-
Journal article (peer-reviewed)abstract
- Eutrophication of coastal ecosystems is a global problem that often results in bottom water oxygen deficiency and in turn promotes sediment phosphorus (P) release (A). In order to increase sediment P retention, we injected dissolved aluminum into the anoxic sediment of a eutrophic semienclosed bay in the Baltic Sea, thereby inhibiting P recycling and further eutrophication (B). The P concentration in the bay remained at half, as did phytoplankton biomass (C), compared to pretreatment conditions and compared to the reference bay. Four years after treatment the water column transparency was increased, allowing submerged vegetation to penetrate deeper, and the habitat suitable for fish and benthic fauna had expanded (D). The lowered P concentration in the bay decreased the P export to the surrounding archipelago. This is the first full-scale marine remediation project using a geo-engineering method that demonstrates a quick recovery. For successful remediation in coastal areas, permanent binding of mobile P in anoxic sediments may be needed together with measures in the catchment area to obtain faster recovery of eutrophicated marine ecosystems.
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| 43. |
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| 44. |
- Sunde, Johanna, et al.
(author)
-
Adaptations of early development to local spawning temperature in anadromous populations of pike (Esox lucius)
- 2019
-
In: BMC Evolutionary Biology. - : BioMed Central. - 1471-2148. ; 19, s. 1-13
-
Journal article (peer-reviewed)abstract
- Background: In the wake of climate change many environments will be exposed to increased and more variable temperatures. Knowledge about how species and populations respond to altered temperature regimes is therefore important to improve projections of how ecosystems will be affected by global warming, and to aid management. We conducted a common garden, split-brood temperature gradient (4.5 degrees C, 9.7 degrees C and 12.3 degrees C) experiment to study the effects of temperature in two populations (10 families from each population) of anadromous pike (Esox lucius) that normally experience different temperatures during spawning. Four offspring performance measures (hatching success, day degrees until hatching, fry survival, and fry body length) were compared between populations and among families. Results: Temperature affected all performance measures in a population-specific manner. Low temperature had a positive effect on the Harfjarden population and a negative effect on the Lervik population. Further, the effects of temperature differed among families within populations. Conclusions: The population-specific responses to temperature indicate genetic differentiation in developmental plasticity between populations, and may reflect an adaptation to low temperature during early fry development in Harfjarden, where the stream leading up to the wetland dries out relatively early in the spring, forcing individuals to spawn early. The family-specific responses to temperature treatment indicate presence of genetic variation for developmental plasticity (G x E) within both populations. Protecting between- and within-population genetic variation for developmental plasticity and high temperature-related adaptive potential of early life history traits will be key to long-term viability and persistence in the face of continued climate change.
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| 45. |
- Sunde, Johanna, et al.
(author)
-
Drivers of neutral and adaptive differentiation in pike (Esox lucius) populations from contrasting environments
- 2022
-
In: Molecular Ecology. - : John Wiley & Sons. - 0962-1083 .- 1365-294X. ; 31:4, s. 1093-1110
-
Journal article (peer-reviewed)abstract
- Understanding how eco-evolutionary processes and environmental factors drive population differentiation and adaptation are key challenges in evolutionary biology of relevance for biodiversity protection. Differentiation requires at least partial reproductive separation, which may result from different modes of isolation such as geographic isolation (allopatry) or isolation by distance (IBD), resistance (IBR), and environment (IBE). Despite that multiple modes might jointly influence differentiation, studies that compare the relative contributions are scarce. Using RADseq, we analyse neutral and adaptive genetic diversity and structure in 11 pike (Esox lucius) populations from contrasting environments along a latitudinal gradient (54.9-63.6 degrees N), to investigate the relative effects of IBD, IBE and IBR, and to assess whether the effects differ between neutral and adaptive variation, or across structural levels. Patterns of neutral and adaptive variation differed, probably reflecting that they have been differently affected by stochastic and deterministic processes. The importance of the different modes of isolation differed between neutral and adaptive diversity, yet were consistent across structural levels. Neutral variation was influenced by interactions among all three modes of isolation, with IBR (seascape features) playing a central role, wheares adaptive variation was mainly influenced by IBE (environmental conditions). Taken together, this and previous studies suggest that it is common that multiple modes of isolation interactively shape patterns of genetic variation, and that their relative contributions differ among systems. To enable identification of general patterns and understand how various factors influence the relative contributions, it is important that several modes are simultaneously investigated in additional populations, species and environmental settings.
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| 46. |
- Sunde, Johanna, et al.
(author)
-
Sex-specific effects of outbreeding on offspring quality in pike (Esox lucius)
- 2018
-
In: Ecology and Evolution. - : WILEY. - 2045-7758. ; 8:21, s. 10448-10459
-
Journal article (peer-reviewed)abstract
- Intraspecific genetic admixture occurs when previously separated populations within a species start interbreeding, and it can have either positive, negative, or neutral effects on reproductive performance. As there currently is no reliable predictor for the outcome of admixture, an increased knowledge about admixture effects in different species and populations is important to increase the understanding about what determines the response to admixture. We tested for effects of admixture on F1 offspring quality in three subpopulations of pike (Esox lucius). Gametes were collected in the field, and eggs from each female were experimentally fertilized with milt from a male from each population (one "pure" and two "admixed" treatments). Three offspring quality measures (hatching success, fry survival, and fry length) were determined and compared between (a) pure and admixed population combinations and (b) the sex-specific treatments within each admixed population combination (based on the origin of the male and female, respectively). The results suggested that although there were no overall effects of admixture on offspring quality, the consequences for a given population combination could be sex-specific and thus differ depending on which of the parents originated from one or the other population. All offspring quality traits were influenced by both maternal ID and paternal ID. Sex- and individual-specific effects can have implications for dispersal behavior and gene flow between natural populations, and are important to consider in conservation efforts.
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| 47. |
- Sunde, Johanna, et al.
(author)
-
Variation in salinity tolerance between and within anadromous subpopulations of pike (Esox lucius)
- 2018
-
In: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 8
-
Journal article (peer-reviewed)abstract
- Environmental heterogeneity is a key determinant of genetic and phenotypic diversity. Stable andhomogenous environments tends to result in evolution of specialism and local adaptations, whiletemporally unpredictable environments may maintain a diversity of specialists, promote generaliststrategies, or favour diversified bet hedging strategies. We compared salinity tolerance between twoanadromous subpopulations of pike (Esox Lucius) that utilize freshwater spawning sites with differentsalinity regimes. Eggs from each population were artificially fertilized and incubated in a salinitygradient (0, 3, 5, 7, and 9 psu) using a split-brood design. Effects on embryonic development, hatchingsuccess, survival of larvae, and fry body length were compared between populations and families.The population naturally spawning in the stable freshwater habitat showed signs of specialization forfreshwater spawning. The population exposed to fluctuating selective pressure in a spawning area withoccasional brackish water intrusions tolerated higher salinities and displayed considerable variation inreaction norms. Genetic differences and plasticity of salinity tolerance may enable populations to copewith changes in salinity regimes associated with future climate change. That geographically adjacentsubpopulations can constitute separate units with different genetic characteristics must be consideredin management and conservation efforts to avoid potentially negative effects of genetic admixture onpopulation fitness and persistence.
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| 48. |
- Tibblin, Petter, et al.
(author)
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Higher abundance of adult pike in Baltic Sea coastal areas adjacent to restored wetlands compared to reference bays
- 2023
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In: Hydrobiologia. - : Springer. - 0018-8158 .- 1573-5117. ; 850, s. 2049-2060
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Journal article (peer-reviewed)abstract
- The abundance of pike, a keystone top-predator, have declined dramatically in the Baltic Sea since the 1990s likely owing to recruitment failure. It has been proposed that wetland restoration can aid the recovery of the pike stock by increasing the number of recruits produced by anadromous populations. Yet, no previous studies have addressed whether wetland restorations are associated with higher abundances of adult pike in the coastal habitat. To address this, we performed standardised rod-and-reel survey fishing in paired bays with and without wetlands across three coastal areas and 3 years. To estimate dispersal and the contribution of wetland pike to the coastal stock, we tagged captured pike with passive integrated responders (PIT) and employed PIT reader stations in wetland inlets. The results showed that pike abundances were on average 90% higher in bays with an adjacent wetland although the effect varied among areas. Moreover, PIT-data uncovered that wetland pike constituted a high proportion of the pike found in adjacent coastal habitats and that some wetland fish dispersed up to 10 km. These results support that wetland restoration is a valuable tool to aid the coastal pike stock and ultimately restore the function and services of the coastal ecosystem.
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| 49. |
- Wennberg, Birgitta, 1956-
(author)
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Keeping track of time : Daily time management, participation, and time-related interventions for children, adolescents, and young adults with neurodevelopmental disorders
- 2019
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Doctoral thesis (other academic/artistic)abstract
- The overall aim of this thesis was to investigate daily time management (DTM) and time-related interventions aiming to enhance participation in everyday activities among school-age children and young adults with neurodevelopmental disorders.In study I, experiences of participation when using time assistive devices (TADs) in daily activities were investigated from the perspective of young adults (aged 17–37) with intellectual disabilities (ID) (n = 9), using semi structured interviews. In studies II and IV, a new multimodal time-related intervention consisting of psychoeducation, compensation with TADs and time-skills training, was investigated in children aged 9–15 with attention-deficit/hyperactivity disorder (ADHD). Study II was a randomized controlled trial (RCT) with an intervention group (n = 19) and a control group (n = 19). The aim of study III was to describe DTM, time processing ability (TPA) and self-rated autonomy in children aged 9–15 with ADHD (n = 47), compared to children with ID (n = 47) and typically developing (TD) children (n = 47). In study IV, occupational performance and satisfaction were evaluated (n = 27). In studies II, III and IV, a source for data collection included assessment, proxy report and self-reports.Using TADs (study I) increased participation in activities in all areas of daily life: self-care, activities at work or school and leisure time activities. A feeling of having more control led to health benefits. Participants described participation restrictions related to attitudes from their social network towards participation and attitudes towards the use of TADs from the individuals themselves. Study II showed that the children in the intervention group increased their TPA significantly more compared to the control group, mostly in terms of time orientation. The parents in the intervention group rated their children’s DTM as significantly more improved compared to the parents of the children in the control group. However, according to the children themselves, there was no statistically significant improvement in their DTM. The psychoeducation for parents and school staff did not increase children’s TPA and DTM on its own. The majority of parents and children (study IV) rated the children’s occupational performance and satisfaction significantly higher at follow-up than at baseline. In general, children rated their occupational performance and satisfaction higher than their parents did. Most goals decided by the children and their parents involved daily routines and time orientation. Study III showed that children with ADHD and children with ID had significantly lower TPA, DTM and autonomy compared to TD children. Children with ADHD showed higher levels of self-rated autonomy compared to children with ID, but the reverse was found in DTM. However, there was significant diversity among children with ADHD and children with ID, which was not explained by age. Some children had difficulties at every level of TPA, while others were skilled at every level. The level of self-rated autonomy followed the level of TPA.In conclusion, this thesis revealed that children with ADHD and ID have the same overall pattern of TPA but may have a delayed TPA, which affects their DTM and autonomy, and thereby also influences their participation in daily activities. The results show that a multimodal time-related intervention using TADs and time-skills training could increase TPA and DTM in children with ADHD aged 9–15 years with time deficits. Experiences from young adults with ID also show increased participation in daily activities and health benefits using TADs. It is recommended that TPA and DTM should be measured to identify difficulties in TPA and DTM in children with ADHD and to offer tailored time-related interventions in addition to medication.
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| 50. |
- Whiss, Per A., 1966-, et al.
(author)
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Acute Effects of Nicotine Infusion on Platelets in Nicotine Users with Normal and Impaired Renal Function
- 2000
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In: Toxicology and Applied Pharmacology. - : Elsevier BV. - 0041-008X .- 1096-0333. ; 163:2, s. 95-104
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Journal article (peer-reviewed)abstract
- The role of platelets in cardiovascular disease associated with smoking is becoming more established, but the effects of nicotine on platelets are unclear. Nicotine therapy is used for smoking cessation in both health and disease. Consequently, the effects of nicotine on platelets are of particular significance in disorders such as renal disease, which is associated with defective platelet function, increased cardiovascular morbidity, and altered nicotine metabolism. Thus, the aim of the present study was to investigate the acute effects of nicotine infusion (NI) on platelets in seven healthy subjects (HS) and seven patients with renal failure (RF). All subjects were nicotine users and had refrained from using nicotine for 36 h before NI. Blood was collected before, immediately after, and 2 h after NI. The plasma concentrations of nicotine and its main metabolite cotinine were determined by gas chromatography. Platelet responsiveness was assessed by aggregometry and flow cytometry in whole blood (P-selectin surface expression, fibrinogen- and von Willebrand factor-binding), P-selectin expression in isolated platelets, and immunoassays of platelet release (β-thromboglobulin, platelet factor 4, and soluble P-selectin) and nitric oxide (NO) products. The plasma levels of cotinine, but not nicotine, were significantly higher in RF compared to HS at all time points. In both groups, collagen-induced platelet aggregation was restrained immediately after NI, when the plasma concentration of nicotine was maximal, and was restored after 2 h. Two hours after NI, activation-dependent P-selectin surface expression in isolated platelets increased in both groups. This increased platelet responsiveness occurred simultaneously with a significant increase of plasma cotinine and a decrease of NO products. Thus, the present study suggests that nicotine, directly or through some secondary mechanism or metabolite, only slightly potentiates some of the platelet responses. Renal failure appears not to influence the effects of nicotine on platelets.
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