| 1. |
- Fraser, Thomas William Kenneth, et al.
(författare)
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Increased reactivity and monoamine dysregulation following stress in triploid Atlantic salmon (Salmo salar)
- 2015
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Ingår i: Comparative Biochemistry and Physiology A. - : Elsevier BV. - 1095-6433 .- 1531-4332. ; 185, s. 125-131
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Tidskriftsartikel (refereegranskat)abstract
- Artificial triploid salmonids are sterile and therefore commercially bred to prevent genetic interactions between wild and domestic fish strains. The full biological effects of having an extra chromosome set are largely unknown, but triploids are considered to be more sensitive to sub-optimal environmental conditions and to be stressed by the presence of diploid conspecifics. Brain serotonergic and dopaminergic activity are known to regulate the stress response in vertebrates, but monoamine systems in diploid and triploid fish have yet to be compared. Here we study monoamine neurochemistry in the telencephalon and brain stem of juvenile diploid and triploid Atlantic salmon (Salmo salar) in response to stress (unstressed vs stressed individuals) and holding (separate- vs mixed-ploidy) conditions. Both diploids and triploids showed an increase in serotonergic activity following stress, but the increase was significantly greater in the telencephalon of triploids compared to diploids. Furthermore, while telencephalic dopaminergic activity was significantly increased in diploids following stress, there was no response in triploids. Holding conditions had a significant effect on dopaminergic activity in the brain stem of diploids only, with lower values in mixed- compared to separate-ploidy conditions. These results suggest artificially produced triploids experience increased reactivity and monoaminergic dysregulation following stress that may impede their welfare and performance.
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| 2. |
- Nordenfelt, Pontus, et al.
(författare)
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Different Requirements for Early and Late Phases of Azurophilic Granule-Phagosome Fusion
- 2009
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Ingår i: TRAFFIC. - : Wiley. - 1398-9219 .- 1600-0854. ; 10:12, s. 1881-1893
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Tidskriftsartikel (refereegranskat)abstract
- Phagocytosis and killing of microorganisms are complex processes that involve tightly regulated membrane traffic events. Because many signaling molecules associate with membrane rafts and because these structures can be found on azurophilic granules, we decided to investigate raft recruitment and the signaling requirements for azurophilic granule secretion during phagosome maturation. At the site of phagocytosis of immunoglobulin G-opsonized prey in human neutrophils, we found that early secretion of azurophilic granules was both raft- and calcium-dependent. Subsequently, rafts at the phagocytic site were internalized with the prey. At the fully formed phagosome, the fusion of azurophilic granules was no longer dependent on rafts or calcium. These findings were found to be true also when using Streptococcus pyogenes bacteria as prey, and depletion of calcium affected the kinetics of bacterial intracellular survival. These findings suggest that the mechanisms for delivery of azurophilic content to nascent and sealed phagosomes, respectively, differ in their dependence on calcium and membrane rafts.
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| 3. |
- Abreu, Murilo S., et al.
(författare)
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Monoaminergic levels at the forebrain and diencephalon signal for the occurrence of mutualistic and conspecific engagement in client reef fish
- 2018
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Social interactions are commonly found among fish as in mammals and birds. While most animals interact socially with conspecifics some however are also frequently and repeatedly observed to interact with other species (i.e. mutualistic interactions). This is the case of the (so-called) fish clients that seek to be cleaned by other fish (the cleaners). Clients face an interesting challenge: they raise enough motivation to suspend their daily activities as to selectively visit and engage in interactions with cleaners. Here we aimed, for the first time, to investigate the region-specific brain monoaminergic level differences arising from individual client fish when facing a cleaner (interspecific context) compared to those introduced to another conspecific (socio-conspecific context). We show that monoaminergic activity differences occurring at two main brain regions, the diencephalon and the forebrain, are associated with fish clients' social and mutualistic activities. Our results are the first demonstration that monoaminergic mechanisms underlie client fish mutualistic engagement with cleanerfish. These pathways should function as a pre-requisite for cleaning to occur, providing to clients the cognitive and physiological tools to seek to be cleaned.
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| 4. |
- Backstroem, Tobias, et al.
(författare)
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Social effects on AVT and CRF systems
- 2021
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Ingår i: Fish Physiology & Biochemistry. - : Springer Nature. - 0920-1742 .- 1573-5168. ; 47:6, s. 1699-1709
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Tidskriftsartikel (refereegranskat)abstract
- Stress and aggression have negative effects on fish welfare and productivity in aquaculture. Thus, research to understand aggression and stress in farmed fish is required. The neuropeptides arginine-vasotocin (AVT) and corticotropin-releasing factor (CRF) are involved in the control of stress and aggression. Therefore, we investigated the effect of agonistic interactions on the gene expression of AVT, CRF and their receptors in juvenile rainbow trout (Oncorhynchus mykiss). The social interactions lead to a clear dominant-subordinate relationship with dominant fish feeding more and being more aggressive. Subordinate fish had an upregulation of the AVT receptor (AVT-R), an upregulation of CRF mRNA levels, and higher plasma cortisol levels. The attenuating effect of AVT on aggression in rainbow trout is proposed to be mediated by AVT-R, and the attenuating effect of the CRF system is proposed to be mediated by CRF.
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| 5. |
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| 6. |
- Backström, Tobias, et al.
(författare)
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Stress effects on AVT and CRF systems in two strains of rainbow trout (Oncorhynchus mykiss) divergent in stress responsiveness
- 2011
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Ingår i: Hormones and Behavior. - : Elsevier BV. - 0018-506X .- 1095-6867. ; 59:1, s. 180-186
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Tidskriftsartikel (refereegranskat)abstract
- The aim for this study was to examine whether the F4 generation of two strains of rainbow trout divergent in their plasma cortisol response to confinement stress (HR: high responder or LR: low responder) would also differ in stress-induced effects on forebrain concentrations of mRNA for corticotropin-releasing factor (CRF). arginine vasotocin (AVT). CRF receptor type 1 (CRF-R1). CRF receptor type 2 (CRF-R2) and AVT receptor (AVT-R). In addition, plasma cortisol concentrations, brainstem levels of monoamines and monoamine metabolites, and behaviour during confinement were monitored. The results confirm that HR and LR trout differ in their cortisol response to confinement and show that fish of these strains also differ in their behavioural response to confinement. The HR trout displayed significantly higher locomotor activity while in confinement than LR trout. Moreover, following 180 min of confinement HR fish showed significantly higher forebrain concentrations of CRF mRNA than LR fish. Also, when subjected to 30 min of confinement HR fish showed significantly lower CRF-R2 mRNA concentrations than LR fish, whereas there were no differences in CRF-R1. AVT or AVT-R mRNA expression between LR and HR fish either at 30 or 180 min of confinement. Differences in the expression of CRF and CRF-R2 mRNA may be related to the divergence in stress coping displayed by these rainbow trout strains.
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| 7. |
- Behere, Anish, 1993-, et al.
(författare)
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Visualization of early oligomeric α‐synuclein pathology and its impact on the dopaminergic system in the (Thy‐1)‐h[A30P]α‐syn transgenic mouse model
- 2021
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Ingår i: Journal of Neuroscience Research. - : John Wiley & Sons. - 0360-4012 .- 1097-4547. ; 99:10, s. 2525-2539
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Tidskriftsartikel (refereegranskat)abstract
- Aggregation of alpha-synuclein (alpha-syn) into Lewy bodies and Lewy neurites is a pathological hallmark in the Parkinson ' s disease (PD) brain. The formation of alpha-syn oligomers is believed to be an early pathogenic event and the A30P mutation in the gene encoding alpha-syn, causing familial PD, has been shown to cause an accelerated oligomerization. Due to the problem of preserving antigen conformation on tissue surfaces, alpha-syn oligomers are difficult to detect ex vivo using conventional immunohistochemistry with oligomer-selective antibodies. Herein, we have instead employed the previously reported alpha-syn oligomer proximity ligation assay (ASO-PLA), along with a wide variety of biochemical assays, to discern the pathological progression of alpha-syn oligomers and their impact on the dopaminergic system in male and female (Thy-1)-h[A30P]alpha-syn transgenic (A30P-tg) mice. Our results reveal a previously undetected abundance of alpha-syn oligomers in midbrain of young mice, whereas phosphorylated (pS129) and proteinase k-resistant alpha-syn species were observed to a larger extent in aged mice. Although we did not detect loss of dopaminergic neurons in A30P-tg mice, a dysregulation in the monoaminergic system was recorded in older mice. Taken together, ASO-PLA should be a useful method for the detection of early changes in alpha-syn aggregation on brain tissue, from experimental mouse models in addition to post mortem PD cases.
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| 8. |
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| 9. |
- Cocco, Arianna, et al.
(författare)
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Characterization of the gamma-aminobutyric acid signaling system in the zebrafish (danio rerio hamilton) central nervous system by reverse transcription-quantitative polymerase chain reaction
- 2017
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Ingår i: Neuroscience. - : Elsevier BV. - 0306-4522 .- 1873-7544. ; 343, s. 300-321
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Tidskriftsartikel (refereegranskat)abstract
- In the vertebrate brain, inhibition is largely mediated by raminobutyric acid (GABA). This neurotransmitter comprises a signaling machinery of GABA(A), GABA(B) receptors, transporters, glutamate decarboxylases (gads) and 4-aminobutyrate aminotransferase (abat), and associated proteins. Chloride is intimately related to GABAA receptor conductance, GABA uptake, and GADs activity. The response of target neurons to GABA stimuli is shaped by chloride-cation co-transporters (CCCs), which strictly control Cl- gradient across plasma membranes. This research profiled the expression of forty genes involved in GABA signaling in the zebrafish (Danio rerio) brain, grouped brain regions and retinas. Primer pairs were developed for reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The mRNA levels of the zebrafish GABA system share similarities with that of mammals, and confirm previous studies in non-mammalian species. Proposed GABAA receptors are alpha(1)beta(2)gamma(2), alpha(1)beta(2)delta, alpha(2b)beta(3), alpha(2b)beta(3)delta, alpha(4)beta(2)gamma(2), alpha(4)beta(2)gamma, alpha(6b)beta(2)gamma(2) and alpha(6b)beta(2)delta. Regional brain differences were documented. Retinal hetero- or homomeric rho-composed GABAA receptors could exist, accompanying alpha(1)beta(y)gamma(2), alpha(1)beta(y)delta, alpha(6a)beta(y)gamma(2,) alpha(6a)beta(y)delta. Expression patterns of alpha(6a) and alpha(6b) were opposite, with the former being more abundant in retinas, the latter in brains. Given the stoichiometry alpha(6w)beta(y)gamma(z), alpha(6a-) or alpha(6b)-containing receptors likely have different regulatory mechanisms. Different gene isoforms could originate after the rounds of genome duplication during teleost evolution. This research depicts that one isoform is generally more abundantly expressed than the other. Such observations also apply to GABAB receptors, GABA transporters, GABA-related enzymes, CCCs and GABAA receptor associated proteins, whose presence further strengthens the proof of a GABA system in zebrafish.
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| 10. |
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| 11. |
- Cocco, Arianna, 1989-, et al.
(författare)
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Neural expression patterns and protein modeling of the GABAA receptor ζ subunit in the adult zebrafish (Danio rerio Hamilton, 1822)
- 2018
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Ingår i: Zebrafish. - 1545-8547 .- 1557-8542.
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Tidskriftsartikel (refereegranskat)abstract
- The zebrafish has a repertoire of twenty-six GABAA receptor subunits, including the paralogues π and ζ, homologous to the mammalian π. The brain mRNA levels of the π subunit are low, but the ζ gene is actively transcribed in D. rerio central nervous system and retinas. With a combined quantitative and qualitative gene expression profiling approach, this research characterized the distribution of the ζ transcript in the brain and eyes of the adult zebrafish. It was demonstrated that there are regional brain differences in the production of this transcript, with the stratum periventriculare of the tecta mesencephali having the highest mRNA levels for ζ. In the adult zebrafish retinas the bipolar cell layer presented staining for the ζ transcript. The three-dimensional structure of the ζ subunit of the GABAA receptor in zebrafish was also calculated in this study, with the human β3 as template. It presented four transmembrane α-helices and an amino-terminal β-loop framed into a disulfide bridge. It was therefore possible to place ζ in the superfamily of Cys-loop membrane proteins, to which GABAA receptor subunits belong. The current study presented a thorough characterization of a unique fish GABAA receptor subunit, which might have specific functions only typical of fish.
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| 12. |
- de Abreu, Murilo S., et al.
(författare)
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The variable monoaminergic outcomes of cleaner fish brains when facing different social and mutualistic contexts
- 2018
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Ingår i: PeerJ. - : PEERJ INC. - 2167-8359. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- The monoamines serotonin and dopamine are important neuromodulators present in the central nervous system, known to be active regulators of social behaviour in fish as in other vertebrates. Our aim was to investigate the region-specific brain monoaminergic differences arising when individual cleaners face a client (mutualistic context) compared to when they are introduced to another conspecific (conspecific context), and to understand the relevance of visual assessment compared to the impact of physical contact with any partner. We demonstrated that serotoninergic activity at the diencephalon responds mostly to the absence of physical contact with clients whereas cerebellar dopaminergic activity responds to actual cleaning engagement. We provide first insights on the brain's monoaminergic (region-specific) response variations, involved in the expression of cleaner fishes' mutualistic and conspecific behaviour. These results contribute to a better understanding of the monoaminergic activity in accordance to different socio-behavioural contexts.
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| 13. |
- Dimitriadou, S., et al.
(författare)
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Brain monoaminergic activity during predator inspection in female Trinidadian guppies (Poecilia reticulata)
- 2023
-
Ingår i: Behavioural Brain Research. - : Elsevier. - 0166-4328 .- 1872-7549. ; 436
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Tidskriftsartikel (refereegranskat)abstract
- To understand the processes underpinning social decision-making, we need to determine how internal states respond to information gathered from the social environment. Brain monoamine neurotransmitters are key in the appraisal of the social environment and can reflect the internal state underlying behavioural responses to social stimuli. Here we determined the effects of conspecific partner cooperativeness during predator inspection on brain monoamine metabolic activity in Trinidadian guppies (Poecilia reticulata). We quantified the concentration of dopamine, serotonin and their metabolites across brain sections sampled immediately after ostensibly expe-riencing cooperation or defection from social partners whilst inspecting a predator model, using a familiar object as a control condition. Our results indicate dopaminergic and serotonergic activity differs with the coopera-tiveness experienced; these different neurotransmission profiles are likely to affect the expression and regulation of downstream behaviours that ultimately contribute to the patterning of cooperative interactions among in-dividuals in a population.
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| 14. |
- Godino-Gimeno, Alejandra, et al.
(författare)
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Obesity Impairs Cognitive Function with No Effects on Anxiety-like Behaviour in Zebrafish
- 2023
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Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 24:15
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Tidskriftsartikel (refereegranskat)abstract
- Over the last decade, the zebrafish has emerged as an important model organism for behavioural studies and neurological disorders, as well as for the study of metabolic diseases. This makes zebrafish an alternative model for studying the effects of energy disruption and nutritional quality on a wide range of behavioural aspects. Here, we used the zebrafish model to study how obesity induced by overfeeding regulates emotional and cognitive processes. Two groups of fish (n = 24 per group) were fed at 2% (CTRL) and 8% (overfeeding-induced obesity, OIO) for 8 weeks and tested for anxiety-like behaviour using the novel tank diving test (NTDT). Fish were first tested using a short-term memory test (STM) and then trained for four days for a long-term memory test (LTM). At the end of the experiment, fish were euthanised for biometric sampling, total lipid content, and triglyceride analysis. In addition, brains (eight per treatment) were dissected for HPLC determination of monoamines. Overfeeding induced faster growth and obesity, as indicated by increased total lipid content. OIO had no effect on anxiety-like behaviour. Animals were then tested for cognitive function (learning and memory) using the aversive learning test in Zantiks AD units. Results show that both OIO and CTRL animals were able to associate the aversive stimulus with the conditioned stimulus (conditioned learning), but OIO impaired STM regardless of fish sex, revealing the effects of obesity on cognitive processes in zebrafish. Obese fish did not show a deficiency in monoaminergic transmission, as revealed by quantification of total brain levels of dopamine and serotonin and their metabolites. This provides a reliable protocol for assessing the effect of metabolic disease on cognitive and behavioural function, supporting zebrafish as a model for behavioural and cognitive neuroscience.
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| 15. |
- Höglund, Erik, et al.
(författare)
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Contrasting neurochemical and behavioral profiles reflects stress coping styles but not stress responsiveness in farmed gilthead seabream (Sparus aurata)
- 2020
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Ingår i: Physiology and Behavior. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0031-9384 .- 1873-507X. ; 214
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Tidskriftsartikel (refereegranskat)abstract
- In fish, as well as in other vertebrates, contrasting suites of physiological and behavioral traits, or coping styles, are often shown in response to stressors. However, the magnitude of the response (i.e. stress responsiveness) has been suggested to be independent of stress coping style. One central neurotransmitter that has been associated with both stress responsiveness and differences in stress coping styles is serotonin (5-hydroxytryptamine, 5-HT). In this study, we investigated to what extent stress responsiveness reflects differences in stress coping, and the potential involvement of the 5-HT system in mediating such differences in farmed Gilthead seabream. Initially, fish were classified as proactive or reactive based on their behavioural response to net restraint. Following 1.5 months, fish classified as proactive still showed a higher number of escape attempts and spent longer time escaping than those classified as reactive. These differences were reflected in a generally higher brain stem 5-HT concentration and a lower telencephalic 5-HT activity, i.e. the ratio of 5-hydroxyindoleacetic acid (5-HIAA) to 5-HT, in proactive fish. Independent of stress coping styles, stress responsiveness was reflected in elevated 5-HIAA concentrations and 5-HIAA/5-HT ratios in telencephalon and brain stem together with increased plasma cortisol concentrations at 0.5 and 2 h following the last net restraint. The current results show that 5-HT signaling can reflect different behavioural output to a challenge which are independent of neuroendocrine responses to stress and lend support to the hypothesis that stress coping styles can be independent of stress responsiveness.
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| 16. |
- Johansson, Sven, et al.
(författare)
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Active Control of Sound using the Actuator-Individual Normalized Filtered-X LMS Algorithm
- 2001
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Konferensbidrag (refereegranskat)abstract
- The control algorithm is a central part of an active noise control system. The computational power of the DSP hardware is limited, and therefore algorithms with high computational complexity allow fewer control sources and sensors to be used, often with reduced noise attenuation as a result. This paper presents results from practical experiments using an ANC system based on the actuator-individual normalized Filtered-X LMS algorithm. The algorithm combines low computational complexity with high performance. For that reason the algorithm is suitable for use in large multi-channel systems in order to reduce the computional power required by the control system.
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| 17. |
- Johansson, Sven, et al.
(författare)
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ACTIVE HEADSET FOR ENHANCED SPEECH INTELLIGIBILITY IN INTERCOM SYSTEMS
- 2001
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Konferensbidrag (refereegranskat)abstract
- Low frequency noise has a masking effect on speech, which significantly reduces the speech intelligibility. Usually, in order to overcome the masking effect the sound level of the communication signal is increased. Exposure to the communication system then causes hearing damage. A feasible approach is to reduce the low frequency noise by using active techniques combined with a method for reducing the noise in the intercom microphone signal. In order to achieve an efficient low frequency noise attenuation inside the headset an active hybrid headset is proposed, and in order to suppress the background noise in speech signals spectral subtraction is used. Improved low frequency noise attenuation enables lower communication levels and reduces the risk for hearing damage.
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| 18. |
- Koeck, Barbara, et al.
(författare)
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Angling selects against active and stress-resilient phenotypes in rainbow trout
- 2019
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Ingår i: Canadian Journal of Fisheries and Aquatic Sciences. - : Canadian Science Publishing. - 0706-652X .- 1205-7533. ; 76:2, s. 320-333
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Tidskriftsartikel (refereegranskat)abstract
- Selection induced by human harvest can lead to different patterns of phenotypic change than selection induced by natural predation and could be a major driving force of evolution of wild populations. The vulnerability of individuals to angling depends on the individual decision to ingest the bait, possibly mediated by their neuroendocrine response towards the associated stimulus. To investigate the mechanisms behind individual vulnerability to angling, we conducted angling experiments in replicated ponds and quantified individual behavioral traits and neuroendocrine stress responsiveness in two salmonid species, rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta). We discovered a phenotypic syndrome in rainbow trout, but not in brown trout, where lower serotonergic and dopaminergic brain activity and cortisol levels (i.e., lower stress responsiveness) in response to a standardized experimental stressor were associated with higher activity, forming a proactive phenotype that showed increased vulnerability to angling. Our results show that angling targets the most stress-resilient and active phenotypes of rainbow trout, supporting the suggestion that fishing-induced phenotypic selection may lead to an increased representation of stress-responsive and low-activity phenotypes in harvested populations.
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| 19. |
- Larsen, M. H., et al.
(författare)
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Effects of Emergence Time and Early Social Rearing Environment on Behaviour of Atlantic Salmon: Consequences for Juvenile Fitness and Smolt Migration
- 2015
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- Consistent individual differences in behaviour have been well documented in a variety of animal taxa, but surprisingly little is known about the fitness and life-history consequences of such individual variation. In wild salmonids, the timing of fry emergence from gravel spawning nests has been suggested to be coupled with individual behavioural traits. Here, we further investigate the link between timing of spawning nest emergence and behaviour of Atlantic salmon (Salmo salar), test effects of social rearing environment on behavioural traits in fish with different emergence times, and assess whether behavioural traits measured in the laboratory predict growth, survival, and migration status in the wild. Atlantic salmon fry were sorted with respect to emergence time from artificial spawning nest into three groups: early, intermediate, and late. These emergence groups were hatchery-reared separately or in co-culture for four months to test effects of social rearing environment on behavioural traits. Twenty fish from each of the six treatment groups were then subjected to three individual-based behavioural tests: basal locomotor activity, boldness, and escape response. Following behavioural characterization, the fish were released into a near-natural experimental stream. Results showed differences in escape behaviour between emergence groups in a net restraining test, but the social rearing environment did not affect individual behavioural expression. Emergence time and social environment had no significant effects on survival, growth, and migration status in the stream, although migration propensity was 1.4 to 1.9 times higher for early emerging individuals that were reared separately. In addition, despite individuals showing considerable variation in behaviour across treatment groups, this was not translated into differences in growth, survival, and migration status. Hence, our study adds to the view that fitness (i.e., growth and survival) and life-history predictions from laboratory measures of behaviour should be made with caution and ideally tested in nature.
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| 20. |
- Magnusson, Kerstin, et al.
(författare)
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Atmosfäriskt nedfall av mikroskräp
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Nedfall av luftburna mikroskopiska skräppartiklar undersöktes på elva lokaler runt om i Sverige. Luftdeponerade plastfibrer, plastfragment, gummipartiklar från fordonsdäck och bomullsfibrer kunde påvisas vid de flesta av provtagningsplatserna, även de som låg på långt avstånd från större tätorter. Studien visar att lufttransport kan vara en betydelsefull spridningsväg för mikroskräp
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| 21. |
- Moltesen, Maria, et al.
(författare)
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Effects of acute and chronic stress on telencephalic neurochemistry and gene expression in rainbow trout (Oncorhynchus mykiss)
- 2016
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 219:24, s. 3907-3914
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Tidskriftsartikel (refereegranskat)abstract
- By filtering relevant sensory inputs and initiating stress responses, the brain is an essential organ in stress coping and adaptation. However, exposure to chronic or repeated stress can lead to allostatic overload, where neuroendocrinal and behavioral reactions to stress become maladaptive. This work examines forebrain mechanisms involved in allostatic processes in teleost fishes. Plasma cortisol, forebrain serotonergic (5-HTergic) neurochemistry, and mRNA levels of corticotropin-releasing factor (CRF), CRF-binding protein (CRFBP), CRF receptors (CRFR1 and CRFR2), mineralocorticoid receptor (MR), glucocorticoid receptors (GR1 and GR2) and serotonin type 1A (5-HT1A) receptors (5-HT1Aα and 5-HT1Aβ) were investigated at 1 h before and 0, 1 and 4 h after acute stress, in two groups of rainbow trout held in densities of 25 and 140 kg m-3 for 28 days. Generally, being held at 140 kg m-3 resulted in a less pronounced cortisol response. This effect was also reflected in lower forebrain 5-HTergic turnover, but not in mRNA levels in any of the investigated genes. This lends further support to reports that allostatic load causes fish to be incapable of mounting a proper cortisol response to an acute stressor, and suggests that changes in forebrain 5-HT metabolism are involved in allostatic processes in fish. Independent of rearing densities, mRNA levels of 5-HT1Aα and MR were downregulated 4 h post-stress compared with values 1 h post-stress, suggesting that these receptors are under feedback control and take part in the downregulation of the hypothalamic-pituitary-interrenal (HPI) axis after exposure to an acute stressor.
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| 22. |
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| 23. |
- Mustafa, Arshi
(författare)
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Neuromolecular and behavioural profile of teleosts : - effects of boldness, agonistic behaviour and reproductive status
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis investigates if boldness is reflected in the function of brain histaminergic system in zebrafish (Danio rerio). Moreover, behavioural differences in AB line, spiegeldanio (spd) line and wild caught strain of zebrafish have also been explored apart from the winner-loser effect in AB and spd fish. This thesis also includes studies on the effect of progestins on reproductive behaviour in zebrafish and regulation of leptinergic system on sexual maturation in male Atlantic salmon (Salmo salar L.).Boldness is reflected in higher expression of histamine receptor 1 (hrh1) in the telencephalon and diencephalon of male zebrafish and dominance by an elevated expression of hrh1 in the optic tectum. In female zebrafish boldness is also associated with lower expression of histamine receptor 3 (hrh3) in the optic tectum and dominance by lower expression of hrh3 in the telencephalon. Comparison of behavioural traits of zebrafish of AB, spd and wild type shows that wild type strain is most shy and shows no gender difference. AB is bolder than spd in the open field test while spd is bolder AB in the novel tank dive test. Similarly results for aggression are also test dependent since the spd is more aggressive than AB in the mirror test, however no difference is measured during dyadic fight test. A typical loser effect and activation of serotonergic system is observed in both AB and spd fish. Further, both levonorgestrel (LNG) and progesterone (P4) cause an early puberty in male zebrafish. However only levonorgestrel causes males biased population at environmental concentrations. In male Atlantic salmon, during early spring, both leptin paralogues, lepa1 and lepa2 in the liver and leptin receptor (lepr) in the brain are downregulated in non-maturing control group. At final maturational stage both hepatic lepa1 and lepa2 are upregulated 7.7 times and 49 times respectively in maturing control males. A significant upregulation of lepr is also measured from mid to late spermatogenesis. This thesis elucidates that an elevated brain histaminergic tone is associated with boldness and dominance and in both sexes changes at gene level are orchestrated by different brain region. Boldness is a contextual trait as it depends on strain, line, sex and test. The loser effect after losing a fight is present in both AB and spd line, however it has been shown for the first time in spd line here. Only androgenic progestin causes male biased population but both androgenic and anti androgenic progestin cause early puberty in zebrafish. The expression of leptinergic system is significantly affected during early sexual maturation in parr stage of salmon. Moreover, depleted fat stores are associated with low leptin levels and feed restriction is association with an elevated leptinergic tone in liver and pituitary. This thesis not only emphasizes that strain vs line difference exists and should be an important criterion before designing any experiment, but it also indicates an important role histaminergic system, progestins and leptinergic system in divergent behaviour profiles, puberty and sexual maturation, respectively of teleosts and contributes to our understanding of it.
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| 24. |
- Mustafa, Arshi, et al.
(författare)
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Spiegeldanio : A bold and aggressive fish but what if it loses a fight?
- 2018
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Ingår i: Measuring Behavior 2018. - 9781910029398 ; , s. 24-26
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Konferensbidrag (refereegranskat)abstract
- IntroductionAggression is a competition based survival strategy. The spiegeldanio (spd) strain of zebrafish (Danio rerio), which has a mutation in the fibroblast growth factor receptor 1a, is bolder and more aggressive than the wild type fish [1]. Usually a socially dominant fish has preferential access to food, mate and shelter, and shows very characteristic postures like erection of the fins. It is also aggressive frequently biting, striking and chasing the subordinate fish as well as threatening its own mirror image in mirror tests [2]. However, what happens when an already known bold and dominant fish like spiegeldanio loses a dyadic fight. Spd fish are more aggressive in mirror tests, attacking their mirror image more frequently than wild type conspecifics. However, are they more aggressive in dyadic fights? Do they show an inhibition of aggressive behaviour when losing fights, the typical loser effect? The behavioural inhibition observed in animals losing fights for dominance is at least in part believed to be mediated by an activation of the brain serotonin (5-hydroxytryptamine, 5-HT) system. Do spd fish show a typical increase in brain 5-HT activity in response to social subordination? Dopamine (DA), on the other hand, is associated with aggression and social dominance. What are the effects of winning and losing fights for social dominance in spd fish? In the present study these questions were addressed in an attempt to increase or understanding of the control of agonistic behaviour and social stress.Animals and MethodsThe Spd strain of zebrafish were raised and reared at 27°C in an Aquaneering Zebrafish system at Uppsala University Biomedical Center. The animals were kept at a 14:10 h of light-dark photoperiod. The water used in the fish tanks was Uppsala municipal tap water (pH 7.2-7.6) of which 10% was exchanged daily. Fish were fed twice daily with Tropical energy food (Aquatic Nature, Belgium) and Artemia (Platinum Grade 0, Argentemia, Argent, Aquaculture, Redmond, USA). The use of animals was approved by the Uppsala Animal Ethical Committee (permit Dnr 55/13) and followed the guidelines of the Swedish Legislation on Animal Experimentation (Animal Welfare Act SFS1998:56), and the European Union Directive on the Protection of Animals Used for Scientific Purposes (Directive 2010/63/EU). The fish were transferred to the individual compartments of dimension 29 x 7.5 x 20 cm (length x breadth x height) in experimental tanks used for dyadic interaction and allowed to recover in isolation overnight. These experimental tanks were made from poly methyl methacrylate plastic and each tank was equipped with a submerged pump with filter (Eheim, typ 2006020, pumping capacity 1/h180, made in China), a heater (Sera aquarium, 25W, made in EU) and an air stone, all of which were placed at the back of the tank separated from the fish by a white perforated PVC screen (Figure 1). The setup of the arena was such that the two fish (1 dyadic pair) had an olfactory but not any visual cue of each other before the dyadic interaction. In the mirror test the fish were made to fight against the mirror image that was displayed in the mirror which was pasted on the wall of the arena. Prior to the beginning of the dyadic contest the mirror was covered with a black plexiglas slide cover. The experiment was carried out in the following sequence: The fishes were netted out and placed in the arena in the compartments A and B (Figure 1) and separated from each other by a partition. The cover of the mirror (opaque black PVC partition, Figure 1) was then removed and fish were made to interact with their own mirror image for 10 minutes. Then the slide covering the mirror was pulled down and the middle separating partition was pulled out and the fish were given an opportunity to fight. Dyadic fight was recorded two times, morning and evening on day one with the help of a video filming camera. Then next day in the morning the dyadic fight was again recorded. During the dyadic interaction the two fishes indulged in mutual display of aggressive behaviour which was followed by chasing and biting attacks performed by the dominant fish over the subordinate fish. Then middle partition was introduced again. Fish were given 6 minutes to habituate and the cover from the mirror was removed and fishes were again allowed to interact with their mirror image. Again the mirror was covered and the fish was allowed to get involved in the dyadic fight. Then each fish was taken out from the compartment at the same time and sacrificed for sampling of brain tissue.The three dimensional model of tank used in the behavioural tests I) Tank used for mirror test and for dyadic fight later on. It consists of two compartments, A and B. The movable partition separating the two compartments would be removed during the dyadic fight test. Compartment C is located at the back and is separated from the compartment A and B with the help of white coloured opaque perforated partition. It contains an air stone (for diffusion of air bubbles), heater (27°C), water pump (for circulation of water) and a drainage tube to exchange the water. II) Diagram of the settings used for dyadic interactions. The mirrors are covered with the help of a black PVC slide and the middle partition is pulled out. This allows the fish to interact.Brain dissection and analysis of monaoamines and monoamine metabolitesBrains were divided into forebrain (telencephalon and diencephalon), optic tectum and the rest (here denoted brain stem). The frozen brains were homogenised in 4% (w/v) ice-cold perchloric acid containing 100 ng/ml 3, 4-dihydroxybenzylamine (DHBA, the internal standard) using a Sonifier cell disruptor B-30 (Branson Ultrasonics, Danbury, CT, USA) and were immediately put on dry ice. Subsequently, the homogenised samples were thawed and centrifuged at 15,000 rpm for 10 min at 4o C. The supernatant was used for high performance liquid chromatography with electrochemical detection (HPLC-EC), analysing the monoamines dopamine (DA) and serotonin (5-hydroxytryptamine, 5-HT) as well as the DA metabolite 3, 4-dihydroxyphenylacetic acid (DOPAC) and the 5-HT metabolite 5-hydroxyindoleacetic acid (5-HIAA), as described by Øverli et al. [3]. In short, the HPLC-EC system consisted of a solvent delivery system model 582 (ESA, Bedford, MA, USA), an autoinjector Midas type 830 (Spark Holland, Emmen, the Netherlands), a reverse phase column (Reprosil-Pur C18-AQ 3 µm, 100 mm × 4 mm column, Dr. Maisch HPLC GmbH, Ammerbuch-Entringen, Germany) kept at 40° C and an ESA 5200 Coulochem II EC detector (ESA, Bedford, MA, USA) with two electrodes at reducing and oxidizing potentials of -40 mV and +320 mV. A guarding electrode with a potential of +450 mV was employed before the analytical electrodes to oxidize any contaminants. The mobile phase consisted of 75 mM sodium phosphate, 1.4 mM sodium octyl sulphate and 10 µM EDTA in deionised water containing 7 % acetonitrile brought to pH 3.1 with phosphoric acid. The quantification of samples was done by comparing it with standard solutions of known concentrations. DHBA was used as an internal standard to correct for recovery with the help of HPLC software ClarityTM (Data Apex Ltd, Czech Republic). The serotonergic and dopaminergic activity was measured as the ratio of 5-HIAA/5-HT and DOPAC/DA respectively. The brain monoamines were normalized with respect to brain protein weights which were determined with Bicinchoninic acid protein determination kit (Sigma Aldrich, Sweden). The assay was read at a wavelength of 570 nm with the help of a plate reader (Labsystems multiskan 352, Labsystems Thermo Fisher Scientific).Results A clear dominant subordinate hierarchy was established within 30 minutes of dyadic interaction. The number of aggressive acts (bites, strikes and chases) performed by the looser fish decreased significantly from the first dyadic fight to the last (i.e. the fourth) dyadic fight. For the winner fish the number of aggressive acts performed against a mirror during the second mirror test increased or remained same as before after winning a dyadic fight, whereas for the looser fish it decreased significantly. The results from the present study indicate that subordinate fish have higher 5-HIAA/5-HT ratio in the optic tectum as compared to the dominants. More results from this study would be presented at the conference.References1. Norton W, Bally-Cuif L (2010) Adult zebrafish as a model organism for behavioural genetics. BMC Neurosci. 11:90.2. Rowland WJ (1999) Studying visual cues in fish behaviour: a review of ethological techniques. Env Biol Fishes. 56:285-305.3. Øverli Ø, Harris CA, Winberg S (1999) Short-term effects of fights for social dominance and the establishment of dominant-subordinate relationships on brain monoamines and cortisol in rainbow trout. Brain Behav Evol. 54:263-275.
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| 25. |
- Mustafa, Arshi, et al.
(författare)
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The aggressive spiegeldanio, carrying a mutation in the fgfr1a gene, has no advantage in dyadic fights with zebrafish of the AB strain
- 2019
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Ingår i: Behavioural Brain Research. - : ELSEVIER SCIENCE BV. - 0166-4328 .- 1872-7549. ; 370
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Tidskriftsartikel (refereegranskat)abstract
- Zebrafish which carries a mutation in the fibroblast growth factor receptor 1A (fgfr1a), also known as spiegeldanio (spd), has previously been reported to be bolder and more aggressive than wildtype (AB) zebrafish. However, in previous studies aggression has been quantified in mirror tests. In dyadic fights the behavior of the combatants is modified by the behavior of their opponent, and fighting a mirror has been reported to have different effects on brain gene expression and brain monoaminergic systems. In the present study aggression was quantified in fgfr1a mutants and AB zebrafish using a mirror test after which the fish were allowed to interact in pairs, either consisting of two fgfr1a mutants or one AB and one fgfr1a mutant fish. Following dyadic interaction aggressive behavior was again quantified in individual fish in a second mirror test after which the fish were sacrificed and brain tissue analyzed for monoamines and monoamine metabolites. The results confirm that fgfr1a mutants are more aggressive than AB zebrafish in mirror tests. However, fgfr1a mutant fish did not have any advantage in fights for social dominance, and agonistic behavior of fgfr1a mutants did not differ from that of AB fish during dyadic interactions. Moreover, as the AB fish, fgfr1a mutant fish losing dyadic interactions showed a typical loser effect and social subordination resulted in an activation of the brain serotonergic system in fgfr1a mutants as well as in AB fish. Overall the effects of dyadic interaction were similar in fgfr1a mutant fish and zebrafish of the AB strain.
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| 26. |
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| 27. |
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| 28. |
- Nordenfelt, Pontus, et al.
(författare)
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Phagosomal membrane rafts : azurophilic origin, Ca2+ dependence, and modulation by Streptococcus pyogenes bacteria
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Uptake and killing of microorganisms by neutrophils involve tightly regulated membrane traffic events that are governed by complex signals. Many of these are raft-associated, which implies that raft dynamics may be important during phagosome formation. Locally restricted, calcium-dependent, parallel upregulation of markers for membrane rafts and azurophilic granules was observed at the site of phagocytosis of IgG-opsonized prey in human neutrophils. Subsequent internalization of the prey reduced the levels of these markers in the plasma membrane. Streptococcus pyogenes bacteria, that can survive phagocytosis by neutrophils, modulated phagosomal raft acquisition by means of M proteins. Continued, but not early, delivery of rafts to the membrane of phagosomes in neutrophils and HL-60 cells was independent of calcium, as was fusion between azurophilic granules and phagosomes. Nevertheless, calcium depletion affected bacterial killing kinetics. These findings suggest that early delivery of membrane rafts is important for phagosomal maturation in neutrophils and provide new mechanistic insight into the processes required for generation of bactericidal phagosomes.
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| 29. |
- Paula, Jose Ricardo, et al.
(författare)
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Neurobiological and behavioural responses of cleaning mutualisms to ocean warming and acidification
- 2019
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Cleaning interactions are textbook examples of mutualisms. On coral reefs, most fishes engage in cooperative interactions with cleaners fishes, where they benefit from ectoparasite reduction and ultimately stress relief. Furthermore, such interactions elicit beneficial effects on clients' ecophysiology. However, the potential effects of future ocean warming (OW) and acidification (OA) on these charismatic associations are unknown. Here we show that a 45-day acclimation period to OW (+3 degrees C) and OA (980 mu atm pCO(2)) decreased interactions between cleaner wrasses (Labroides dimidiatus) and clients (Naso elegans). Cleaners also invested more in the interactions by providing tactile stimulation under OA. Although this form of investment is typically used by cleaners to prolong interactions and reconcile after cheating, interaction time and client jolt rate (a correlate of dishonesty) were not affected by any stressor. In both partners, the dopaminergic (in all brain regions) and serotoninergic (forebrain) systems were significantly altered by these stressors. On the other hand, in cleaners, the interaction with warming ameliorated dopaminergic and serotonergic responses to OA. Dopamine and serotonin correlated positively with motivation to interact and cleaners interaction investment (tactile stimulation). We advocate that such neurobiological changes associated with cleaning behaviour may affect the maintenance of community structures on coral reefs.
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| 30. |
- Persson, Mikael, et al.
(författare)
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In vitro evaluation of two polyhedral boron anion derivatives as linkers for attachment of radioiodine to the anti-HER2 monoclonal antibody trastuzumab
- 2007
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Ingår i: Cancer Biotherapy and Radiopharmaceuticals. - : Mary Ann Liebert Inc. - 1084-9785 .- 1557-8852. ; 22:5, s. 585-596
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Tidskriftsartikel (refereegranskat)abstract
- Improving intracellular retention is important for the use of radiohalogens in radionuclide therapy usinginternalizing antibodies. Two putative linkers for residualization of radioiodine labels, 7-(4-isothiocyanato-phenyl)undecahydro-7,8-dicarba-nido-undecaborate(1Ϫ) ion (NBI) and (4-isothiocyanato-benzylammo-nio)undecahydro-closo-dodecaborate(1Ϫ) (DABI), were analyzed. The anti-HER-2 antibody, trastuzumab,was labeled with iodine-125 using NBI and DABI linkers, and, for comparison, with the para-[125I]iodoben-zoate (PIB), and Chloramine-T (CAT) methods. The different labels were tested for residualizing prop-erties using the HER-2 overexpressing SKBR-3 cells. The cellular radioactivity retention showed thatDABI provided a 55% better retention than CAT and was 42% better than PIB after 20 hours. NBI didnot improve retention. Accumulation tests up to 21 hours showed that the HER-2-specific accumulationof radioactivity delivered with DABI was, on average, 33% higher than with the use of PIB. These DABI-dependent improvements could, with high probability, be attributed to the good residualizing propertiesof DABI. The affinity of DABI-labeled trastuzumab to SKBR-3 cells was not better than the affinity of thePIB labeled (3.2 Ϯ 1.9 nM and 0.77 Ϯ 0.39 nM, respectively). In conclusion, the use of the DABI linkerimproved intracellular retention in vitro in comparison with the other labeling methods.
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| 31. |
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| 32. |
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| 33. |
- Rosengren, Malin, 1982, et al.
(författare)
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High risk no gain-metabolic performance of hatchery reared Atlantic salmon smolts, effects of nest emergence time, hypoxia avoidance behaviour and size
- 2017
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Ingår i: Physiology & Behavior. - : Elsevier BV. - 0031-9384 .- 1873-507X. ; 175, s. 104-112
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Tidskriftsartikel (refereegranskat)abstract
- When animals are reared for conservational releases it is paramount to avoid reducing genetic and phenotypic variation over time. This requires an understanding of how diverging behavioural and physiological traits affect performance both in captivity and after release. In Atlantic salmon, emergence time from the spawning gravel has been linked to certain behavioural and physiological characteristics and to the concept of stress coping styles. Early emerging fry has for example been shown to be bolder and more aggressive and to have higher standard metabolic rates compared to late emerging fry. The first aim was therefore to examine if emergence latency affect the behavioural stress coping response also beyond the fry and parr stage. This was done using a hypoxia avoidance test, where an active behavioural avoidance response can be related to higher risk taking. No behavioural differences were found between the two emergence fractions either at the parr or pre-smolt stage, instead smaller individuals were more prone to express an "active" hypoxia avoidance response. Further, an individual expressing a "passive" response as parr were also more prone to express this behaviour at the pre-smolt stage. While there are some previous studies showing that early emerging individuals with a bolder personality may be favored within a hatchery setting it is not known to what extent these early differences persist to affect performance after release. The second aim was therefore to compare the physiological performance at the time of release as smolts using the two subgroups; 1) early emerging fish showing active hypoxia avoidance (Early + Bold) and 2) late emerging fish showing a passive hypoxia response (Late + Shy). The Early + Bold group showed a higher red blood cell swelling, suggesting a higher adrenergic output during stress, whereas there was no difference in post-stress plasma cortisol or physiological smolt status. While there was no difference in standard metabolic rate between the groups, the Early + Bold group exhibited a lower maximum metabolic rate and aerobic scope following strenuous swimming. In captivity this may have no clear negative effects, but in the wild, a more risk prone behavioural profile linked to a lower aerobic capacity to escape from e.g. a predator attack, could clearly be disadvantageous.
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| 34. |
- Rosengren, Malin, 1982, et al.
(författare)
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The brain-gut axis of fish: Rainbow trout with low and high cortisol response show innate differences in intestinal integrity and brain gene expression
- 2018
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Ingår i: General and Comparative Endocrinology. - : Elsevier BV. - 0016-6480 .- 1095-6840. ; 257, s. 235-245
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Tidskriftsartikel (refereegranskat)abstract
- © 2017 Elsevier Inc. In fish, the stress hormone cortisol is released through the action of the hypothalamic pituitary interrenal axis (HPI-axis). The reactivity of this axis differs between individuals and previous studies have linked this to different behavioural characteristics and stress coping styles. In the current study, low and high responding (LR and HR) rainbow trout in terms of cortisol release during stress were identified, using a repeated confinements stress test. The expression of stress related genes in the forebrain and the integrity of the stress sensitive primary barrier of the intestine was examined. The HR trout displayed higher expression levels of mineralocorticoid and serotonergic receptors and serotonergic re-uptake pumps in the telencephalon during both basal and stressed conditions. This confirms that HPI-axis reactivity is linked also to other neuronal behavioural modulators, as both the serotonergic and the corticoid system in the telencephalon are involved in behavioural reactivity and cognitive processes. Involvement of the HPI-axis in the brain-gut-axis was also found. LR trout displayed a lower integrity in the primary barrier of the intestine during basal conditions compared to the HR trout. However, following stress exposure, LR trout showed an unexpected increase in intestinal integrity whereas the HR trout instead suffered a reduction. This could make the LR individuals more susceptible to pathogens during basal conditions where instead HR individuals would be more vulnerable during stressed conditions. We hypothesize that these barrier differences are caused by regulation/effects on tight junction proteins possibly controlled by secondary effects of cortisol on the intestinal immune barrier or differences in parasympathetic reactivity.
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| 35. |
- Sbragaglia, Valerio, et al.
(författare)
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Evolutionary implications of size-selective mortality on the ontogenetic development of shoal cohesion : a neurochemical approach using a zebrafish, Danio rerio, harvest selection experiment
- 2022
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer. - 0340-5443 .- 1432-0762. ; 76:12
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Tidskriftsartikel (refereegranskat)abstract
- Size-selective mortality may evolutionarily alter life-history as well as individual behavioral and physiological traits. Moreover, size-selective mortality can affect group behavioral traits, such as shoaling and collective properties (e.g., shoal cohesion), which are relevant for finding food and reducing risk of predation. Here, we present experimental evidence using selection lines of zebrafish (Danio rerio) that were exposed to positive ( large-harvested), negative (small-harvested), and random (control) size-selective mortality for five generations, followed by eight generations during which harvesting was halted to remove maternal effects and to study evolutionarily fixed outcomes. We investigated changes in shoal cohesion and turnover in monoamines in zebrafish through ontogeny. To that end, we repeatedly measured inter-individual distance in groups of eight fish and the turnovers of dopamine and serotonin in brains of fish from juvenile to the adult stage at 40-day intervals. We, firstly, found that shoal cohesion was overall consistent through ontogeny at group levels suggesting the presence of collective personality. Secondly, we found a decrease in shoal cohesion through ontogeny in the small-harvested and control lines, while the large-harvested line did not show any ontogenetic change. Thirdly, the selection lines did not differ among each other in shoal cohesion at any ontogenetic stage. Fourthly, dopamine turnover increased through ontogeny in a similar way for all lines while the serotonin turnover decreased in the large-harvested and control lines, but not in the small-harvested line. The large-harvested line also had higher serotonin turnover than controls at specific time periods. In conclusion, intensive size-selective mortality left an evolutionary legacy of asymmetric selection responses in the ontogeny of shoal cohesion and the underlying physiological mechanisms in experimentally harvested zebrafish in the laboratory. Significant statement The evolution of animal behavior can be affected by human activities both at behavioral and physiological levels, but causal evidence is scarce and mostly focusing on single life-stages. We studied whether and to what extent size-selective harvesting, a common selection pattern in fisheries, can be an evolutionary driver of the development of shoal cohesion during ontogeny. We used a multi-generation experiment with zebrafish to study cause-and-effects of opposing size-selection patterns. We quantified shoal cohesion, and serotonin and dopamine turnover in the brain. We found that shoal cohesion emerged as a collective personality trait and that behavioral and physiological responses were asymmetrical with respect to the opposing selection patterns.
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| 36. |
- Sen Sarma, Oly, et al.
(författare)
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Optimizing zebrafish rearing-Effects of fish density and environmental enrichment
- 2023
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Ingår i: Frontiers in Behavioral Neuroscience. - : Frontiers Media SA. - 1662-5153. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- Introduction; Despite its popularity in research, there is very little scientifically validated knowledge about the best practices on zebrafish (Danio rerio) husbandry, which has led to several facilities having their own husbandry protocols. This study was performed to expand knowledge on the effects of enrichment and fish density on the welfare of zebrafish, with hopes of providing a scientific basis for future recommendations and legislations.Methods: Zebrafish were reared at three different stocking densities, (1, 3 or 6 fish/L), in tanks with or without environmental enrichment. Agonistic behavior was observed twice a week for 9 weeks directly in the housing tanks. Aspects of welfare is known to be reflected in neuroendocrine stress responses. Thus, cortisol secretion in response to lowering the water level was analyzed for each group. In addition, we assessed cortisol secretion in response to confinement and risk-taking behavior (boldness) using the novel tank diving test for individual fish. At termination of the experiment fish were subjected to stress by transfer to a novel environment and brain tissue was sampled for analysis of brain monoaminergic activity.Results: Fish kept at the lowest density (1 fish/L) showed a significantly higher level of aggression than fish kept at 3 or 6 fish/L. Moreover, fish kept at this low density showed significantly higher cortisol secretion on a group level than fish kept at the higher stocking densities, when subjected to lowering of the water level. Keeping fish at 1 fish/L also had effects on brain monoamines, these fish showing higher brain dopamine concentrations but lower dopamine turnover than fish kept at higher densities. Neither stocking density or enrichment had any clear effects on the behavior of individual fish in the novel tank diving test. However, fish kept at high densities showed lower and more variable growth rates than fish kept at 1 fish/L.Discussion: Taken together these results suggest that zebrafish should not be kept at a density of 1 fish/L. The optimal stocking density is likely to be in the range of 3-6 fish/L.
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| 37. |
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| 38. |
- Skogby, Sandra, 1989, et al.
(författare)
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Outpatient volumes and medical staffing resources as predictors for continuity of follow-up care during transfer of adolescents with congenital heart disease
- 2020
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Ingår i: International Journal of Cardiology. - : Elsevier. - 0167-5273 .- 1874-1754. ; 310, s. 51-57
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Providing continuous follow-up care to patients with congenital heart disease (CHD) remains a challenge in many settings. Previous studies highlight that patients with CHD experience discontinuation of follow-up care, but mainly describe a single-centre perspective, neglecting inter-institutional variations. Hospital-related factors above and beyond patient-related factors are believed to affect continuity of care. The present multicentre study therefore investigated (i) proportion of "no follow-up care"; (ii) transfer destinations after leaving paediatric cardiology; (iii) variation in proportions of no follow-up between centres; (iv) the association between no follow-up and outpatient volumes, and (v) its relationship with staffing resources at outpatient clinics.METHODS: An observational, multicentre study was conducted in seven university hospitals. In total, 654 adolescents with CHD, born between 1991 and 1993, with paediatric outpatient visit at age 14-18 years were included. Transfer status was determined 5 years after the intended transfer to adult care (23y), based on medical files, self-reports and registries.RESULTS: Overall, 89.7% of patients were receiving adult follow-up care after transfer; 6.6% had no follow-up; and 3.7% were untraceable. Among patients in follow-up care, only one remained in paediatric care and the majority received specialist adult CHD care. Significant variability in proportions of no follow-up were identified across centres. Higher outpatient volumes at paediatric outpatient clinics were associated with better continued follow-up care after transfer (OR = 1.061; 95% CI = 1.001 - 1.124). Medical staffing resources were not found predictive.CONCLUSION: Our findings support the theory of hospital-related factors influencing continuity of care, above and beyond patient-related characteristics.
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| 39. |
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| 40. |
- Thunqvist, Per, et al.
(författare)
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Lung function after extremely preterm birth-A population-based cohort study (EXPRESS)
- 2018
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Ingår i: Pediatric Pulmonology. - : Wiley. - 8755-6863 .- 1099-0496. ; 53:1, s. 64-72
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND OBJECTIVES: Follow-up studies of children and young adults born very-to-moderately preterm show persistent and significant lung function deficits. The aim of the study was to determine lung function and airway mechanics in school-aged children born in 2004 to 2007 and extremely preterm (after 22-26 weeks of gestation).METHODS: In a population-based cohort of children born extremely preterm and controls born at term (n = 350), follow-up at 6½-years-of-age was performed using spirometry and impulse oscillometry. Associations to gestational age, smallness for gestational age (SGA), and bronchopulmonary dysplasia (BPD) were assessed.RESULTS: Children born extremely preterm had lower forced vital capacity (FVC, z-score: -0.7, 95%CI: -1.0;-0.4), forced expiratory volume (FEV1 , z-score: -1.1, 95%CI: -1.4; -0.8), higher frequency-dependence of resistance (R5-20 , 0.09, 95%CI: 0.05; 0.12 kPa · L-1 · s-1 ) and larger area under the reactance curve (AX, 0.78, 95%CI: 0.49; 1.07 kPa · L-1 ) than controls. In children born at 22-24 weeks of gestation, 24% had FVC and 44% had FEV1 below the lower limit of normal. SGA and severe BPD only marginally contributed to pulmonary outcomes. Asthma-like disease was reported in 40% of extremely preterm children and 15% of controls.CONCLUSION: Many children born extremely preterm have altered airway mechanics and significant obstructive reduction in lung function. This warrants consideration for treatment and continued follow-up.
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| 41. |
- Thörnqvist, Per-Ove, et al.
(författare)
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Bold zebrafish (Danio rerio) express higher levels of delta opioid and dopamine D2 receptors in the brain compared to shy fish
- 2019
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Ingår i: Behavioural Brain Research. - : Elsevier. - 0166-4328 .- 1872-7549. ; 359, s. 927-934
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Tidskriftsartikel (refereegranskat)abstract
- Individual variation in coping with environmental challenges is a well-known phenomenon across vertebrates, including teleost fish. Dopamine is the major transmitter in the brain reward networks, and important for motivational processes and stress coping. Functions of the endogenous opioid system are not well studied in teleosts. However, in mammals the activity in the brain reward networks is regulated by the endogenous opioid system. This study aimed at investigating if there was a correlation between risk-taking behavior and the expression of dopamine and opioid receptors in the zebrafish (Danio rerio) brain. Risk-taking behavior was assessed in a novel tank diving test, and the most extreme high risk taking, i.e. bold, and low risk taking, i.e. shy, fish were sampled for qPCR analysis of whole brain gene expression. The expression analysis showed a significantly higher expression of the dopamine D2 receptors (drd2a and drd2b) and the delta opioid receptor (DOR; oprd1b) in bold compared to shy fish. Besides reward and reinforcing properties, DORs are also involved in emotional responses. Dopamine D2 receptors are believed to be important for active stress coping in rodents, and taken together the results of the current study suggest similar functions in zebrafish. However, additional experiments are required to clarify how dopamine and opioid receptor activation affect behavior and stress coping in this species.
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| 42. |
- Thörnqvist, Per-Ove, et al.
(författare)
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Natural selection constrains personality and brain gene expression differences in Atlantic salmon (Salmo salar)
- 2015
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 218:7, s. 1077-1083
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Tidskriftsartikel (refereegranskat)abstract
- In stream-spawning salmonid fishes there is a considerable variation in the timing of when fry leave the spawning nests and establish a feeding territory. The timing of emergence from spawning nests appears to be related to behavioural and physiological traits, e.g. early emerging fish are bolder and more aggressive. In the present study, emerging Atlantic salmon (Salmo salar L.) alevins were sorted into three fractions: early, intermediate and late emerging. At the parr stage, behaviour, stress responses, hindbrain monoaminergic activity and forebrain gene expression were explored in fish from the early and late emerging fractions (first and last 25%). The results show that when subjected to confinement stress, fish from the late emerging fraction respond with a larger activation of the brain serotonergic system than fish from the early fraction. Similarly, in late emerging fish, stress resulted in elevated expression of mRNA coding for serotonin 1A receptors (5-HT1A), GABA-A receptor-associated protein and ependymin, effects not observed in fish from the early emerging fraction. Moreover, fish from the early emerging fraction displayed bolder behaviour than their late emerging littermates. Taken together, these results suggest that time of emergence, boldness and aggression are linked to each other, forming a behavioural syndrome in juvenile salmon. Differences in brain gene expression between early and late emerging salmon add further support to a relationship between stress coping style and timing of emergence. However, early and late emerging salmon do not appear to differ in hypothalamus-pituitary-interrenal (HPI) axis reactivity, another characteristic of divergent stress coping styles.
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| 43. |
- Ullah, Imdad, et al.
(författare)
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Effects of early rearing enrichments on modulation of brain monoamines and hypothalamic-pituitary-interrenal axis (HPI axis) of fish mahseer (Tor putitora)
- 2020
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Ingår i: Fish Physiology & Biochemistry. - : SPRINGER. - 0920-1742 .- 1573-5168. ; 46:1, s. 75-88
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Tidskriftsartikel (refereegranskat)abstract
- Enriching rearing environment is the strategy suggested for improving the post release survivorship of captive-reared animals. Here, an attempt has been made to evaluate the impact of early rearing enrichment on the hypothalamic-pituitary-interrenal axis (HPI axis), blood glucose, and brain dopaminergic and serotonergic systems of Tor putitora. Fifteen-day-old hatchlings of T. putitora were reared up to advanced fry stage in barren, semi-natural, and physically enriched environments and compared them with regard to pre-stress and post-stress levels of whole-body cortisol, blood glucose, brain serotonergic activity (5HIAA/5HT ratio), dopaminergic activity (DOPAC/DA and HVA/DA ratios) and norepinephrine (NE) levels. Significantly low basal whole-body cortisol, glucose and brain NE levels were observed in a physically enriched group of fish as compared to the other two groups. However, after acute stress, all rearing groups showed elevated levels of cortisol, blood glucose, brain 5HIAA/5HT, DOPAC/DA and HVA/DA ratios and NE levels but the magnitude of response was different among different rearing groups. The barren reared group showed a higher magnitude of response as compared to semi-natural and physically enriched groups. Similarly, the recovery rate of whole-body cortisol, blood glucose, and whole-brain monoamines were long-lasting in barren-reared mahseer. We illustrate that increased structural complexity (physical enrichment) during the early rearing significantly modulates various physiological and stress-coping mechanisms of mahseer.
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| 44. |
- Ullah, Imdad, et al.
(författare)
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Effects of enrichment on the development of behaviour in an endangered fish mahseer (Tor putitora)
- 2017
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Ingår i: Applied Animal Behaviour Science. - : Elsevier BV. - 0168-1591 .- 1872-9045. ; 186, s. 93-100
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Tidskriftsartikel (refereegranskat)abstract
- Structural enrichment in the rearing environment, not only promotes fish welfare, but also affects several aspects of behavioural biology of fish in aquaculture. Here an attempt was made to use physical enrichment to improve the behaviour of hatchery-reared fish. In this study, three groups of 15 days old mahseer (Tor putitora) hatchlings were reared up to advanced fry stage in barren (without any substrate), physically-enriched (gravel bed, substrate and plants) and semi-natural environments (earthen pond having a natural feed) respectively and the behavioural profiles of fish from these environments were compared. We illustrate that increased structural complexity during early life significantly affect various behavioural characteristics of the fish. Exploratory behaviour, predation and anti-predatory response were significantly (p < 0.05) higher in fish reared in physical enrichment and semi-natural environment than in barren-reared fish. These results have important implications for a possible way of improving the outcomes of restocking program of endangered fish species by modifying conventional hatchery-rearing environments.
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| 45. |
- Vindas, Marco A., et al.
(författare)
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How do individuals cope with stress? : Behavioural, physiological and neuronal differences between proactive and reactive coping styles in fish
- 2017
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 220:8, s. 1524-1532
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Tidskriftsartikel (refereegranskat)abstract
- Despite the use of fish models to study human mental disorders and dysfunctions, knowledge of regional telencephalic responses in non-mammalian vertebrates expressing alternative stress coping styles is poor. As perception of salient stimuli associated with stress coping in mammals is mainly under forebrain limbic control, we tested region-specific forebrain neural (i.e. mRNA abundance and monoamine neurochemistry) and endocrine responses under basal and acute stress conditions for previously characterised proactive and reactive Atlantic salmon. Reactive fish showed a higher degree of the neurogenesis marker proliferating cell nuclear antigen (pcna) and dopamine activity under basal conditions in the proposed hippocampus homologue (Dl) and higher post-stress plasma cortisol levels. Proactive fish displayed higher post-stress serotonergic signalling (i.e. higher serotonergic activity and expression of the 5-HT1A receptor) in the proposed amygdala homologue (Dm), increased expression of the neuroplasticity marker brain-derived neurotropic factor (bdnf) in both Dl and the lateral septum homologue (Vv), as well as increased expression of the corticotropin releasing factor 1 (crf(1)) receptor in the Dl, in line with active coping neuro-profiles reported in the mammalian literature. We present novel evidence of proposed functional equivalences in the fish forebrain with mammalian limbic structures.
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| 46. |
- Vossen, Laura E., et al.
(författare)
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Chronic Exposure to Oxazepam Pollution Produces Tolerance to Anxiolytic Effects in Zebrafish (Danio rerio)
- 2020
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 54:3, s. 1760-1769
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Tidskriftsartikel (refereegranskat)abstract
- Environmental concentrations of the anxiolytic drug oxazepam have been found to disrupt antipredator behaviors of wild fish. Most experiments exposed fish for a week, while evidence from mammals suggests that chronic exposure to therapeutic concentrations of benzodiazepines (such as oxazepam) results in the development of tolerance to the anxiolytic effects. If tolerance can also develop in response to the low concentrations found in the aquatic environment, it could mitigate the negative effects of oxazepam pollution. In the current study, we exposed wild-caught zebrafish to oxazepam (similar to 7 mu g L-1) for 7 or 28 days and evaluated behavioral and physiological parameters at both time points. Females showed reduced diving responses to conspecific alarm pheromone after 7 days, but not after 28 days, indicating that they had developed tolerance to the anxiolytic effects of the drug. Zebrafish males were not affected by this oxazepam concentration, in line with earlier results. Serotonin turnover (ratio 5-HIAA/5-HT) was reduced in exposed females and males after 28 days, indicating that brain neurochemistry had not normalized. Post-confinement cortisol concentrations and gene expression of corticotropin-releasing hormone (CRH) were not affected by oxazepam. We did not find evidence that chronically exposed fish had altered relative expression of GABA A receptor subunits, suggesting that some other still unknown mechanism caused the developed tolerance.
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| 47. |
- Vossen, Laura E., et al.
(författare)
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Low concentrations of the benzodiazepine drug oxazepam induce anxiolytic effects in wild-caught but not in laboratory zebrafish
- 2020
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 703
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Tidskriftsartikel (refereegranskat)abstract
- Pollution by psychoactive pharmaceuticals has been found to disrupt anti-predator behaviors of wild fish. The challenge is now to identify which of the many psychoactive drugs pose the greatest threat. One strategy is to screen for behavioral effects of selected pharmaceuticals using a single, widely available fish species such as zebrafish. Here, we show that although such high-throughput behavioral screening might facilitate comparisons between pharmaceuticals, the choice of strain is essential. While wild-caught zebrafish exposed to concentrations of the anxiolytic drug oxazepam as low as 0.57 μg L−1 showed a reduction in the response to conspecific alarm pheromone, laboratory strain AB did not respond to the alarm cue, and consequently, the anxiolytic effect of oxazepam could not be measured. Adaptation to the laboratory environment may have rendered laboratory strains unfit for use in some ecotoxicological and pharmacological studies, since the results might not translate to wild fish populations.
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| 48. |
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| 49. |
- Vossen, Laura E., et al.
(författare)
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Zebrafish (Danio rerio) behaviour is largely unaffected by elevated pCO2
- 2016
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Ingår i: Conservation Physiology. - : Oxford University Press (OUP). - 2051-1434. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- Ocean acidification, the decrease in ocean pH caused by anthropogenic emission of carbon dioxide, can cause behavioural disturbances in marine teleost species. We investigated whether AB-strain zebrafish (Danio rerio) show similar behavioural disturbances in the presence of elevated CO2, because this model species could open up a toolbox to investigate the physiological and neurological mechanisms of CO2 exposure. We found no effect of elevated CO2 (~1600 μatm) on the behaviour of zebrafish in the open field test, indicating that zebrafish are largely insensitive to this elevated CO2 level. In the detour test of lateralization, however, zebrafish exposed to elevated CO2 swam more often to the right, whereas individuals exposed to control CO2 (~400 μatm) had no preference for left or right. This may indicate that some behaviours of some freshwater fishes can be altered by elevated CO2 levels. Given that elevated CO2 levels often occur in recirculating aquaculture and aquarium systems, we recommend that dissolved CO2 levels are measured and, if necessary, the aquarium water should be aerated, in order to exclude CO2 level as a confounding factor in experiments.
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| 50. |
- Winberg, Cecilia, et al.
(författare)
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Feeling controlled or being in control? : Apps for self-management among older people with neurological disability
- 2021
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Ingår i: Disability and Rehabilitation. - : Taylor & Francis. - 1748-3107 .- 1748-3115. ; 16:6, s. 603-608
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The aim of this paper was to describe how people living with a neurological disability such as multiple sclerosis, Parkinson’s disease and stroke reason regarding using apps to facilitate self-management in everyday life.Material and methods: A qualitative research approach with a focus group methodology was used. The sample comprised 16 participants, 11 men and 5 women, with an average age of 64 years (ranging from 51–80 years). Six participants were diagnosed with multiple sclerosis, six with Parkinson’s disease and four with stroke. Data were analyzed using thematic analysis, which is a method for identifying, analyzing and reporting patterns.Results: The results formed two themes. The first theme “using apps to have control of my health” comprises two subthemes; “monitor and take responsibility for a healthy lifestyle” and “compensate to facilitate everyday life”. The second theme “using the app as a tool and means for communication” also comprised two subthemes; “dare to trust the app” and “feeling safe when sharing information with health care professionals”.Conclusions: The use of apps put increased responsibility on the person and had the possibility to make them more involved in their own care. The use of an app can facilitate a healthy lifestyle and help to monitor disease-specific symptoms. In order to be able to use apps for communication with the health care sector legislation and safety issues need to be considered.
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