| 1. |
- Jutfelt, Fredrik, et al.
(författare)
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Brain cooling marginally increases acute upper thermal tolerance in Atlantic cod
- 2019
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 222:19
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Tidskriftsartikel (refereegranskat)abstract
- Physiological mechanisms determining thermal limits in fishes are debated but remain elusive. It has been hypothesised that motor function loss, observed as loss of equilibrium during acute warming, is due to direct thermal effects on brain neuronal function. To test this, we mounted cooling plates on the heads of Atlantic cod (Gadus morhua) and quantified whether local brain cooling increased whole-organism acute upper thermal tolerance. Brain cooling reduced brain temperature by 2-6 °C below ambient water temperature and increased thermal tolerance by 0.5 and 0.6 °C on average relative to instrumented and uninstrumented controls, respectively, suggesting that direct thermal effects on brain neurons may contribute to setting upper thermal limits in fish. However, the improvement in thermal tolerance with brain cooling was small relative to the difference in brain temperature, demonstrating that other mechanisms (e.g. failure of spinal and peripheral neurons, or muscle) may also contribute to controlling acute thermal tolerance.
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| 2. |
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| 3. |
- Norin, Tommy, et al.
(författare)
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Predator presence affects activity patterns but not food consumption or growth of juvenile corkwing wrasse (Symphodus melops)
- 2021
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer. - 0340-5443 .- 1432-0762. ; 75:1
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Tidskriftsartikel (refereegranskat)abstract
- Indirect effects of predators can manifest themselves as changes in prey behaviour and physiology. Given that digestion requires energy, it has been suggested that prey will choose to eat smaller meals under predation risk to reserve a larger portion of the aerobic metabolic scope they have available for energetically demanding tasks more critical than digestion, such as escape. To test this prediction, we quantified food consumption and growth of juvenile corkwing wrasses (Symphodus melops) over 11 days in the presence or absence of a predator (Atlantic cod, Gadus morhua). We then quantified behaviour and food consumption of the same wrasses in behavioural arenas with a predator. All food consumption was examined in the context of the aerobic scope that would have been available during the digestive period. Overall, there was no effect of predator exposure on food consumption or growth, yet predator-exposed wrasses were more consistent in their daily food consumption, lending some support to our prediction of prey bet-hedging on meal size under predation risk. The lack of a clear pattern may have resulted from a relatively low percentage of aerobic scope (similar to 20-27%) being occupied by digestion, such that fish retained ample capacity for activities other than digestion. In the subsequent behavioural trials, predator-exposed wrasses were more active and spent more time near the cod than predator-naive wrasses, suggesting the former had habituated to predation threat and were more risk-taking. Our results highlight the complex and often counter-intuitive effects that predator presence can have on prey populations beyond direct consumption. Significance statement Predators affect the behaviour of prey species by simply being present in the environment. Such intimidation by predators can change activity patterns of prey and be as important as direct predation for ecosystem dynamics. However, compared to behavioural changes, we know little about how predators indirectly affect prey physiology. We investigated if fish deliberately eat less food when a predator is present, in order to retain sufficient physiological capacity for avoiding a potential attack, on top of the energetically costly process of digesting. While our study confirms that predator encounters reduce prey activity, prey fish appeared to rapidly habituate to predator presence and we did not see reduced food consumption in predator-exposed fish; these were, however, more consistent than unexposed fish in their daily food consumption, suggesting that fish may still be mindful about protecting their aerobic capacity under predation risk.
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| 4. |
- Roche, Dominique G., et al.
(författare)
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Behavioural lateralization in a detour test is not repeatable in fishes
- 2020
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Ingår i: Animal Behaviour. - : Elsevier BV. - 0003-3472 .- 1095-8282. ; 167, s. 55-64
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Tidskriftsartikel (refereegranskat)abstract
- Behavioural lateralization, the asymmetric expression of cognitive functions, is reported to enhance key fitness-relevant traits such as group coordination, multitasking and predator escape. Therefore, studies reporting negative effects on lateralization in fish due to environmental stressors such as ocean acidification, hypoxia and pollutants are worrisome. However, such studies tend to use a detour test and focus on population level measures, without validating whether lateralization is consistent within individuals across time. We conducted a multispecies, international assessment of the repeatability (R) of lateralization in four previously studied fish species using a detour test (T-maze), a common method for testing lateralization. We also reanalysed a published data set on a fifth species using new statistical methods. We expected the three shoaling species to exhibit greater within-individual consistency in lateralization than their nonshoaling counterparts given previous reports of stronger lateralization in group-living fishes. Absolute and relative lateralization scores were highly nonrepeatable in all five species (0.01<R<0.08), irrespective of their shoaling status. We carefully reviewed 31 published studies in which the detour test was employed to examine lateralization in fish and identified statistical issues in all of them. We develop and propose new statistical analyses to test for population and individual level lateralization. The commonly used detour test does not appear to be appropriate for quantifying behavioural lateralization in fishes, calling into question functional inferences drawn by many published studies, including our own. Potential fitness benefits of lateralization and anthropogenic effects on lateralization as a proxy for adaptive brain functioning need to be assessed with alternative paradigms.
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| 5. |
- Rosen, Lars, 1962, et al.
(författare)
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SCORE: A novel multi-criteria decision analysis approach to assessing the sustainability of contaminated land remediation
- 2015
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 511, s. 621-638
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Tidskriftsartikel (refereegranskat)abstract
- The multi-criteria decision analysis (MCDA) method provides for a comprehensive and transparent basis for performing sustainability assessments. Development of a relevant MCDA-method requires consideration of a number of key issues, e.g. (a) definition of assessment boundaries, (b) definition of performance scales, both temporal and spatial, (c) selection of relevant criteria (indicators) that facilitate a comprehensive sustainability assessment while avoiding double-counting of effects, and (d) handling of uncertainties. Adding to the complexity is the typically wide variety of inputs, including quantifications based on existing data, expert judgements, and opinions expressed in interviews. The SCORE (Sustainable Choice Of REmediation) MCDA-method was developed to provide a transparent assessment of the sustainability of possible remediation alternatives for contaminated sites relative to a reference alternative, considering key criteria in the economic, environmental, and social sustainability domains. The criteria were identified based on literature studies, interviews and focus-group meetings. SCORE combines a linear additive model to rank the alternatives with a non-compensatory approach to identify alternatives regarded as non-sustainable. The key strengths of the SCORE method are as follows: a framework that at its core is designed to be flexible and transparent; the possibility to integrate both quantitative and qualitative estimations on criteria; its ability, unlike other sustainability assessment tools used in industry and academia, to allow for the alteration of boundary conditions where necessary; the inclusion of a full uncertainty analysis of the results, using Monte Carlo simulation; and a structure that allows preferences and opinions of involved stakeholders to be openly integrated into the analysis. A major insight from practical application of SCORE is that its most important contribution may be that it initiates a process where criteria otherwise likely ignored are addressed and openly discussed between stakeholders.
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| 6. |
- Rosen, Lars, 1962, et al.
(författare)
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SCORE: Multi-Criteria Analysis (MCA) for Sustainability Appraisal of Remedial Alternatives
- 2013
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Ingår i: R.R. Sirabian and R. Darlington (Chairs), Bioremediation and Sustainable Environmental Technologies—2013. Second International Symposium on Bioremediation and Sustainable Environmental Technologies (Jacksonville, FL; June 10–13, 2013). - 9780981973074
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Konferensbidrag (refereegranskat)abstract
- For comprehensive and transparent appraisal of sustainability, multicriteria analysis (MCA) is often suggested. Development of a relevant MCA-method requires consideration of a number of key issues, e.g., (a) definition of assessment boundaries; (b) definition of performance scales, both temporal and spatial; (c) selection of relevant criteria (indicators) that facilitates a comprehensive sustainability appraisal while avoiding double-counting of effects; and (d) handling of uncertainties. Adding to the complexity is the typically wide variety of inputs, including uantifications based on existing data, expert judgments, and opinions expressed in interviews. The sustainable choice of remediation (SCORE) MCA-method is developed to provide a transparent appraisal of the sustainability of possible remediation alternatives relative to a reference alternative, considering key criteria in the economic, environmental and social domains. The criteria were identified based on extensive literature studies and focus-group meetings. The economic domain has one key criterion: social profitability, evaluated by cost-benefit analysis. The environmental domain criteria are: soil, surface water, groundwater, sediment, air, non-recyclable waste, and non-renewable natural resources. The social domain criteria are: local environmental quality & amenity; cultural heritage; equity; health and safety; local participation; and local acceptance. SCORE combines a linear additive model to rank the alternatives with outranking to identify alternatives regarded as non-sustainable. The method is capable of integrating quantitative and qualitative estimations of criteria and provides a full uncertainty analysis of the results, using Monte Carlo simulation. Most importantly, it provides a structure that allows preferences and opinions of involved stakeholders to be openly integrated into the analysis.
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| 7. |
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| 8. |
- Tjellstrom, Bo, et al.
(författare)
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Effect of exclusive enteral nutrition on gut microflora function in children with Crohns disease
- 2012
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa Healthcare. - 0036-5521 .- 1502-7708. ; 47:12, s. 1454-1459
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Exclusive enteral nutrition (EEN) is a first-line treatment in children with active Crohns disease (CD) but is seldom used in adults with active disease. The mode of action of EEN in suppressing mucosa] inflammation is not fully understood, but modulation of intestinal microflora activity is one possible explanation. The aim of this study was to investigate the effect of 6-week EEN in children with active CD, with special reference to intestinal microflora function. Materials and methods. Fecal samples from 18 children (11 boys, 7 girls; median age 13.5 years) with active CD (13 children with small bowel/colonic and 5 with perianal disease) were analyzed for short chain fatty acid (SCFA) pattern as marker of gut microflora function. The children were studied before and after EEN treatment. Results from 12 healthy teenagers were used for comparison. Results. Eleven (79%) of the children with small bowel/colonic CD responded clinically positively to EEN treatment showing decreased levels of pro-inflammatory acetic acid as well as increased concentrations of anti-inflammatory butyric acids and also of valeric acids, similar to the levels in healthy age-matched children. In children with active perianal CD, however, EEN had no positive effect on clinical status or inflammatory parameters. Conclusions. The authors present new data supporting the hypothesis that the well-documented anti-inflammatory effect of EEN in children with active small bowel/colonic CD is brought about by modulation of gut microflora activity, resulting in an anti-inflammatory SCFA pattern. By contrast, none of the children with perianal disease showed clinical or biochemical improvement after EEN treatment.
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| 9. |
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| 10. |
- Tjellstrom, B., et al.
(författare)
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The effects of oats on the function of gut microflora in children with coeliac disease
- 2014
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Ingår i: Alimentary Pharmacology and Therapeutics. - : Wiley. - 0269-2813 .- 1365-2036. ; 39:10, s. 1156-1160
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Tidskriftsartikel (refereegranskat)abstract
- Background Faecal short chain fatty acids (SCFAs) are produced by the gut microflora. We have previously reported high faecal SCFA levels in children with coeliac disease (CD), indicating alteration in gut microfloral metabolism. Data accumulated over recent decades by us and others suggest that wheat-free oats can safely be included in a gluten-free diet (GFD). However, concerns have been raised with respect to the safety of oats in a subset of coeliacs. Aim To describe faecal SCFA patterns in children with newly diagnosed CD treated for 1year with a GFD with or without oats. Methods This report is part of a randomised, double-blind study on the effect of a GFD containing oats (GFD-oats) vs. a standard GFD (GFD-std). Faecal samples were received from 34 children in the GFD-oats group and 37 in the GFD-std group at initial diagnosis and/or after 1year on a GFD. Faecal SCFAs were analysed. Results The GFD-std group had a significantly lower total faecal SCFA concentration at 12months compared with 0months (Pless than0.05). In contrast, total SCFA in the GFD-oats group remained high after 1year on the GFD. The children in the GFD-oats group had significantly higher acetic acid (Pless than0.05), n-butyric acid (Pless than0.05) and total SCFA concentration (Pless than0.01) after 1-year diet treatment compared to the GFD-std group. Conclusions Our results indicate that oats do affect the gut microflora function, and that some coeliac children receiving oats may develop gut mucosal inflammation, that may present a risk for future complications.
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| 11. |
- Tjellström, Bo, et al.
(författare)
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Faecal short-chain fatty acid pattern in childhood coeliac disease is normalised after more than one year's gluten-free diet
- 2013
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Ingår i: Microbiological Ecology in Health and Disease. - Järfälla, Sweden : Co-Action Publishing. - 0891-060X .- 1651-2235. ; 24
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Recent work indicates that the gut microflora is altered in patients with coeliac disease (CD). Faecal short-chain fatty acids (SCFAs) are produced by the gut microflora. We have previously reported a high SCFA output in children with symptomatic and asymptomatic CD at presentation, as well as in CD children on a gluten-free diet (GFD) for less than 1 year, indicating deviant gut microfloral function. In this report, we focus on faecal SCFA production in coeliacs on GFD for more than 1 year.MATERIALS AND METHODS: Faecal samples were collected from 53 children with CD at presentation, 74 coeliac children on GFD for less than 1 year, and 25 individuals diagnosed with CD in childhood and on GFD for more than 1 year. The control group comprised 54 healthy children (HC). The faecal samples were analysed to show the SCFA pattern taken as a marker of gut microflora function. We applied a new fermentation index, reflecting the inflammatory activity of the SCFAs (amount of acetic acid minus propionic acid and n-butyric acid, together divided by the total amount of SCFAs).RESULTS: In coeliacs on GFD for more than 1 year, the individual SCFAs, total SCFA, and fermentation index did not differ significantly from the findings in controls. In contrast, the faecal SCFA level was clearly higher in coeliacs treated with GFD for less than 1 year compared to those more than 1 year.CONCLUSIONS: This is the first study on SCFA patterns in faecal samples from individuals with CD on GFD for more than 1 year. Our study indicates that the disturbed gut microflora function in children with CD at presentation and after less than 1 year of GFD, previously demonstrated by us, is normalised on GFD for more than 1 year.
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| 12. |
- Tjellström, Bo, et al.
(författare)
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Gut microflora associated characteristics in children with celiac disease
- 2005
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Ingår i: American Journal of Gastroenterology. - : Ovid Technologies (Wolters Kluwer Health). - 0002-9270 .- 1572-0241. ; 100:12, s. 2784-2788
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The aim of the study was to investigate the metabolic function of intestinal microflora in children with celiac disease (CD) in order to find out if there is a deviant gut flora in CD patients compared to healthy controls. METHODS: The study group comprised children with CD, consecutively diagnosed according to current criteria given by the European Society for Paediatric Gastroenterology, Hepatology, and Nutrition. Thirty-six children were studied at presentation, i.e., on a normal gluten-containing diet, with clinical symptoms and signs indicative of CD, positive celiac serology markers, and a small bowel biopsy showing severe enteropathy. Forty-seven patients were studied when they had been on a gluten-free diet (GFD) for at least 3 months. For comparison, a group of 42 healthy controls (HC) were studied. The functional status of the intestinal microflora was evaluated by gas-liquid chromatography of short chain fatty acids (SCFAs) in fecal samples. RESULTS: There was a significant difference between untreated CD children and HC as well as between treated CD children and HC regarding acetic, i-butyric, i-valeric acid, and total SCFAs. The propionic and n-valeric acids differed significantly between CD children on GFD and HC. Moreover, there was a strong correlation between i-butyric and i-valeric acids in all study groups. CONCLUSIONS: This is the first study of the SCFA pattern in fecal samples from children with CD. The results indicate that there is a difference in the metabolic activity of intestinal microbial flora in children with CD compared to that in HC. The finding of a different pattern of some SCFAs in celiacs both at presentation and during treatment with GFD indicates that it is a genuine phenomenon of CD not affected by either the diet, the inflammation, or the autoimmune status of the patient. © 2005 by Am. Coll. of Gastroenterology Published by Blackwell Publishing.
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| 13. |
- Tjellström, Bo, et al.
(författare)
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Gut microflora associated characteristics in first-degree relatives of children with celiac disease
- 2007
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 0036-5521 .- 1502-7708. ; 42:10, s. 1204-1208
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Tidskriftsartikel (refereegranskat)abstract
- Objective. In celiac disease (CD), enteropathy of the small bowel results from a T-cell-mediated reaction to gluten in the diet. In addition to gluten, other environmental and genetic factors participate in the disease pathogenesis. We have recently reported the finding of a significantly different short-chain fatty acid (SCFA) profile in fecal samples from children with CD compared to healthy controls reflecting an aberrant gut microflora. The aim of the present study was to make a functional evaluation of the gut microflora status in non-celiac 1st degree relatives of children with CD. Material and methods. Fecal samples from 76 symptom-free, non-celiac, 1st degree CD relatives and from 91 aged-matched healthy controls were analyzed for fecal tryptic activity (FTA) and a number of SCFAs. Results. There was a significantly lower level of acetic acid and total SCFAs as well as a significantly increased level of i-butyric acid and FTA in relatives compared to healthy controls. Conclusions. The FTA and the SCFA profiles in fecal samples from 1st degree relatives of children with CD are different from those of healthy individuals. The implication of this observation provides insight into the pathogenesis of CD and opens up the possibility of future new diagnostic, therapeutic and prophylactic strategies. © 2007 Taylor & Francis.
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| 14. |
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| 15. |
- Tjellström, Bo, et al.
(författare)
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Screening-detected and symptomatic untreated celiac children show similar gut microflora-associated characteristics
- 2010
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Ingår i: SCANDINAVIAN JOURNAL OF GASTROENTEROLOGY. - : Informa Healthcare. - 0036-5521 .- 1502-7708. ; 45:9, s. 1059-1062
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Tidskriftsartikel (refereegranskat)abstract
- Objective. The aim of this study was to investigate the metabolic function of intestinal microflora in children with screening-detected celiac disease (CD) to see if there is an aberrant gut flora in screening-detected CD similar to symptomatic CD and contrary to healthy controls. Materials and methods. As part of a Swedish multicenter screening for CD, 912 12-year-old children were screened with serum anti-human tissue transglutaminase-IgA. Small bowel biopsy specimens from children with positive serology revealed 17 individuals with CD. The functional status of the intestinal microflora was evaluated by gas liquid chromatography of short chain fatty acids (SCFAs) in fecal samples. Our previously published findings in children with symptomatic CD and healthy controls were used as comparison. Results. The children with screening-detected CD had a similar fecal SCFA profile to children with symptomatic CD, but differed significantly from that in healthy children. Conclusions. This is the first study on SCFA patterns in fecal samples from children with screening-detected CD. The similarity of the fecal SCFA profile in screening-detected and symptomatic CD indicates common pathogenic mechanisms. This could open the way for new therapeutic or prophylactic measures based on novel biological principles.
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| 16. |
- Åberg, Denny, et al.
(författare)
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Steps to Microwave Probing of Complex Dielectric Bodies
- 2005
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Ingår i: Midwest Symposium on Circuits and Systems, Volume 2005. - 0780391977 ; , s. 1932-1935
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Microwave probing of dielectric materials is a challenging application of microwaves. This study investigates a Finite Difference Time Domain electro-magnetic wave simulation tool with the intent of establishing a quantitative simulation environment for microwave probing techniques. Measurements were compared to simulations on distilled water and a phantom resembling a human breast with and without a 10 mm diameter tumor. The measurements showed high signal differences on tumor insertion as well as on variation of the tumor position within the phantom. The simulation results shows agreement on quantitative levels for the whole phantom object, however the simulation results on tumor variation could not be quantitatively correlated to measurements
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