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- Fernandez, Celine, et al.
(författare)
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Hormone-sensitive lipase is necessary for normal mobilization of lipids during sub-maximal exercise.
- 2008
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Ingår i: American Journal of Physiology: Endocrinology and Metabolism. - : American Physiological Society. - 1522-1555 .- 0193-1849. ; 295, s. 179-186
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Tidskriftsartikel (refereegranskat)abstract
- For the working muscle there are a number of fuels available for oxidative metabolism, including glycogen, glucose and non-esterified fatty acids. Non-esterified fatty acids originate from lipolysis in white adipose tissue, from hydrolysis of VLDL-triglycerides or from hydrolysis of intramyocellular triglyceride stores. A key enzyme in the mobilization of fatty acids from intracellular lipid stores is hormone-sensitive lipase (HSL). The aim of the present study was to investigate the metabolic response of HSL-null mice challenged with exercise or fasting and to examine if other lipases are able to fully compensate for the lack of HSL. The results showed that HSL-null mice have reduced capacity to perform aerobic exercise. The liver glycogen stores were more rapidly depleted in HSL-null mice during treadmill exercise and HSL-null mice had reduced plasma concentrations of both glycerol and non-esterified fatty acids after exercise and fasting, respectively. The data support the hypothesis that in the absence of HSL mice are not able to respond to an exercise challenge with increased mobilization of the lipid stores. Consequently, the impact of the lipid sparing effect on liver glycogen will be reduced in the HSL-null mice, resulting in faster depletion of this energy source, contributing to the decreased endurance during sub-maximal exercise. Key words: Treadmill exercise, lipid metabolism, glycogen, skeletal muscle, liver.
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- Henryson, Kajsa, et al.
(författare)
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Environmental performance of crop cultivation at different sites and nitrogen rates in Sweden
- 2019
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Ingår i: Nutrient Cycling in Agroecosystems. - : SPRINGER. - 1385-1314 .- 1573-0867. ; 114:2, s. 139-155
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Tidskriftsartikel (refereegranskat)abstract
- Nitrogen (N) fertilisation has positive and negative effects on the environmental impact of crop cultivation. The mechanisms governing these effects are highly site-dependent, a factor often ignored in assessments of the environmental impact of crop cultivation. By assessing outputs of crop rotations using a life cycle approach, this study explored how greenhouse gas emissions and marine eutrophication caused by crop cultivation (including upstream processes such as production of farm inputs) depend on fertiliser rate and the site at which the cultivation occurs. Cereal unit (CU) was used as the functional unit. The calculations were based on data from multi-site long-term field experiments in Sweden and site-dependent data and models for non-measured processes. Cultivation at three N levels was evaluated, where the highest N rate was close to current average practices and the lowest level corresponded to one-third of that. Site characteristics had a stronger influence on both greenhouse gas emissions and marine eutrophication (variations of up to 330% and 490%, respectively, within N levels) than N level (variations of up to 74% and 59%, respectively, within sites). Main sources of variation in greenhouse gas emissions were soil nitrous oxide emissions (58-810g CO2eqCU-1) and soil organic carbon changes (14-720g CO2eqCU-1), while variations in marine eutrophication were mainly explained by field-level waterborne N losses (0.9-8.2g NeqCU-1). The large variation between sites highlights the importance of considering site characteristics when assessing the environmental impact of crop cultivation and evaluating the environmental consequences of crop management practices.
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- Ström, Kristoffer, et al.
(författare)
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Attainment of brown adipocyte features in white adipocytes of hormone-sensitive lipase null mice.
- 2008
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 3:3
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Hormone-sensitive lipase (HSL) is expressed predominantly in adipose tissue, where it plays an important role in catecholamine-stimulated hydrolysis of stored tri- and diglycerides, thus mobilizing fatty acids. HSL exhibits broad substrate specificity and besides acylglycerides it hydrolyzes cholesteryl esters, retinyl esters and lipoidal esters. Despite its role in fatty acid mobilization, HSL null mice have been shown to be resistant to diet-induced obesity. METHODOLOGY/PRINCIPAL FINDINGS: Following a high-fat diet (HFD) regimen, energy expenditure, measured using indirect calorimetry, was increased in HSL null mice. White adipose tissue of HSL null mice was characterized by reduced mass and reduced protein expression of PPARgamma, a key transcription factor in adipogenesis, and stearoyl-CoA desaturase 1, the expression of which is known to be positively correlated to the differentiation state of the adipocyte. The protein expression of uncoupling protein-1 (UCP-1), the highly specific marker of brown adipocytes, was increased 7-fold in white adipose tissue of HSL null mice compared to wildtype littermates. Transmission electron microscopy revealed an increase in the size of mitochondria of white adipocytes of HSL null mice. The mRNA expression of pRb and RIP140 was decreased in isolated white adipocytes, while the expression of UCP-1 and CPT1 was increased in HSL null mice compared to wildtype littermates. Basal oxygen consumption was increased almost 3-fold in white adipose tissue of HSL null mice and was accompanied by increased uncoupling activity. CONCLUSIONS: These data suggest that HSL is involved in the determination of white versus brown adipocytes during adipocyte differentiation The exact mechanism(s) underlying this novel role of HSL remains to be elucidated, but it seems clear that HSL is required to sustain normal expression levels of pRb and RIP140, which both promote differentiation into the white, rather than the brown, adipocyte lineage.
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- Voss, Logan J., et al.
(författare)
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Investigation into the effect of the general anaesthetic etomidate on local neuronal synchrony in the mouse neocortical slice
- 2013
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Ingår i: Brain Research. - : Elsevier. - 0006-8993 .- 1872-6240. ; 1526, s. 65-70
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Tidskriftsartikel (refereegranskat)abstract
- How general anaesthetic drugs cause unconsciousness is a topic of ongoing clinical and scientific interest. It is becoming increasingly apparent that they disrupt cortical information processing, but the effects appear to depend on the spatial scale under investigation. In this study we investigated whether the intravenous anaesthetic etomidate synchronises neuronal activity on a sub-millimetre scale in mouse neocortical slices. In slices generating no-magnesium seizure-like event (SLE) field activity, we analysed the morphology of field potential activity recorded with 50 mu m extracellular electrodes. The analysis was based on the understanding that the amplitude and sheerness of field potential oscillations correlates with the synchrony of the underlying neural activity. When recorded from the region of the slice initiating SLE activity, etomidate consistently increased both population event amplitude (median(range) 85(24-350) to 101(30-427) mu V) and slope 16.6(1.5-106.2) to 20.2(1.7-111.1) mu V/ms (p=0.016 and p=0.0013, respectively). The results are consistent with an increase in neuronal synchrony within the receptive field of the recording electrode, estimated to be a circle diameter of 300 mu m. In conclusion, the neocortical slice preparation supports in vivo data showing that general anaesthetics increase neuronal synchrony on a local scale and provides an ideal model for investigating underlying mechanisms.
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| 7. |
- Voss, Logan J., et al.
(författare)
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Investigation into the effect of the general anaesthetics etomidate and ketamine on long-range coupling of population activity in the mouse neocortical slice
- 2012
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Ingår i: European Journal of Pharmacology. - : Elsevier. - 0014-2999 .- 1879-0712. ; 689:1-3, s. 111-117
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Tidskriftsartikel (refereegranskat)abstract
- General anaesthetics have been hypothesised to ablate consciousness by decoupling intracortical neural connectivity. We explored this by investigating the effect of etomidate and ketamine on coupling of neural population activity using the low magnesium neocortical slice model. Four extracellular electrodes (50 mu m) were positioned in mouse neocortical slices (400 mu m thick) with varying separation. The effect of etomidate (24 mu M) and ketamine (16 mu M) on the timing of population activity recorded between channels was analysed. No decoupling was observed at the closest electrode separation of 0.2 mm. At 4 mm separation, decoupling was observed in 50% and 42% of slices during etomidate and ketamine delivery, respectively (P less than 0.0001 and P=0.002, compared to 0.2mm separation). A lower rate of decoupling was observed with 1 mm separation (21% and 8%, respectively, P less than 0.03 for etomidate compared to 0.2 mm separation). The data support the hypothesis that mechanistically diverse general anaesthetics disrupt neuronal connectivity across widely distributed intracortical networks.
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| 8. |
- Ahlberg, Erik, et al.
(författare)
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"Vi klimatforskare stödjer Greta och skolungdomarna"
- 2019
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Ingår i: Dagens nyheter (DN debatt). - 1101-2447.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- DN DEBATT 15/3. Sedan industrialiseringens början har vi använt omkring fyra femtedelar av den mängd fossilt kol som får förbrännas för att vi ska klara Parisavtalet. Vi har bara en femtedel kvar och det är bråttom att kraftigt reducera utsläppen. Det har Greta Thunberg och de strejkande ungdomarna förstått. Därför stödjer vi deras krav, skriver 270 klimatforskare.
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| 9. |
- Ahlgren, Serina, et al.
(författare)
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EU sustainability criteria for biofuels : Uncertainties in GHG emissions from cultivation
- 2012
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Ingår i: Biofuels. - : Informa UK Limited. - 1759-7269 .- 1759-7277. ; 3:4, s. 399-411
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Tidskriftsartikel (refereegranskat)abstract
- Background: Cultivation of raw material represents a large proportion of biofuelś GHG emissions. The EU renewable energy directive 2009/28/EC specifies a GHG emission default value for cultivation of biofuel raw material (23 g CO2-e/MJ ethanol for wheat). The aim of this study was to quantify the uncertainty in GHG emissions for wheat cultivation in Sweden, considering uncertainty and variability in data at farm level. Results: Two levels of data collection at farm level were analyzed; simple (only yield and amount of N) and advanced (also including amounts and types of energy). The 2.5-97.5 percentile uncertainty for Swedish winter wheat was 20-27 g CO 2-e/MJ, which can be considered large in the context of the Directives threshold of 23 g (to two significant figures). Conclusion: It is concluded that quantifying GHG emissions in order to regulate biofuels is a difficult task, especially emissions from cultivation, since these are biological systems with large variability.
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