| 1. |
- Arnoldsson, Kristina, 1961-
(författare)
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Polybrominated dibenzo-p-dioxins : Natural formation mechanisms and biota retention, maternal transfer, and effects
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Polybrominated dibenzo-p-dioxins (PBDD) and dibenzofurans (PBDF) are a group of compounds of emerging interest as potential environmental stressors. Their structures as well as toxic responses are similar to the highly characterized toxicants polychlorinated dibenzo-p-dioxins. High levels of PBDDs have been found in algae, shellfish, and fish, also from remote areas in theBaltic Sea. This thesis presents studies on PBDD behavior in fish and offspring, and natural formation of PBDDs from naturally abundant phenolic precursors.The uptake, elimination, and maternal transfer of mono- to tetraBDD/Fs were investigated in an exposure study reported in Paper I. The effects of PBDDs in fish were examined in a dose-response study (Paper II). It was shown that fish can assimilate PBDD/Fs from their feed, although non-laterally substituted congeners were rapidly eliminated. Laterally substituted congeners were retained as was congeners without vicinal hydrogens to some extent. PBDD/Fs were transferred to eggs, and congeners that were rapidly eliminated in fish showed a higher transfer ratio to eggs. Exposure to the laterally substituted 2,3,7,8-TeBDD had significant effects on the health, gene expression and several reproduction end-points of zebrafish, even at the lowest dose applied.The geographical and temporal variations of PBDD in biota samples from the Baltic Seasuggest biogenic rather than anthropogenic origin. In Paper III, bromoperoxidase-mediated coupling of 2,4,6-tribromophenol yielded several PBDD congeners, some formed after rearrangement. The overall yield was low, but significantly higher at low temperature, and the product profile obtained was similar to congener profiles found in biota from the Swedish West Coast. In Paper IV, photochemically induced cyclization of hydroxylated polybrominated diphenyl ethers under natural conditions produced PBDDs at percentage yield. Rearranged products were not detected, and some abundant congeners do not seem to be formed this way. However, the product profile obtained was similar to congener profiles found in biota from the Baltic Proper.Since the PBDD congeners found in biota have a high turn-over in fish, the exposure must be high and continuous to yield the PBDD levels measured in wild fish. Thus, PBDDs must presumably be formed by common precursors in general processes, such as via enzymatic oxidations, UV-initiated reactions or a combination of both. The presented pathways for formation of PBDDs are both likely sensitive to changes in climatic conditions.
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| 2. |
- Barker, ED, et al.
(författare)
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Do ADHD-impulsivity and BMI have shared polygenic and neural correlates?
- 2021
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Ingår i: Molecular psychiatry. - : Springer Science and Business Media LLC. - 1476-5578 .- 1359-4184. ; 26:3, s. 1019-1028
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Tidskriftsartikel (refereegranskat)abstract
- There is an extensive body of literature linking ADHD to overweight and obesity. Research indicates that impulsivity features of ADHD account for a degree of this overlap. The neural and polygenic correlates of this association have not been thoroughly examined. In participants of the IMAGEN study, we found that impulsivity symptoms and body mass index (BMI) were associated (r = 0.10, n = 874, p = 0.014 FWE corrected), as were their respective polygenic risk scores (PRS) (r = 0.17, n = 874, p = 6.5 × 10−6 FWE corrected). We then examined whether the phenotypes of impulsivity and BMI, and the PRS scores of ADHD and BMI, shared common associations with whole-brain grey matter and the Monetary Incentive Delay fMRI task, which associates with reward-related impulsivity. A sparse partial least squared analysis (sPLS) revealed a shared neural substrate that associated with both the phenotypes and PRS scores. In a last step, we conducted a bias corrected bootstrapped mediation analysis with the neural substrate score from the sPLS as the mediator. The ADHD PRS associated with impulsivity symptoms (b = 0.006, 90% CIs = 0.001, 0.019) and BMI (b = 0.009, 90% CIs = 0.001, 0.025) via the neuroimaging substrate. The BMI PRS associated with BMI (b = 0.014, 95% CIs = 0.003, 0.033) and impulsivity symptoms (b = 0.009, 90% CIs = 0.001, 0.025) via the neuroimaging substrate. A common neural substrate may (in part) underpin shared genetic liability for ADHD and BMI and the manifestation of their (observable) phenotypic association.
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| 3. |
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| 4. |
- Ehlers, Ina, 1984-, et al.
(författare)
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Elucidating Turnover Pathways of Bioactive Small Molecules by Isotopomer Analysis : The Persistent Organic Pollutant DDT
- 2014
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Ingår i: PLOS ONE. - : PLoS ONE. - 1932-6203. ; 9:10, s. e110648-
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Tidskriftsartikel (refereegranskat)abstract
- The persistent organic pollutant DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane) is still indispensable in the fight againstmalaria, although DDT and related compounds pose toxicological hazards. Technical DDT contains the dichloro congenerDDD (1-chloro-4-[2,2-dichloro-1-(4-chlorophenyl)ethyl]benzene) as by-product, but DDD is also formed by reductive degradation of DDT in the environment. To differentiate between DDD formation pathways, we applied deuterium NMR spectroscopy to measure intramolecular deuterium distributions (2H isotopomer abundances) of DDT and DDD. DDD formed in the technical DDT synthesis was strongly deuterium-enriched at one intramolecular position, which we traced back to 2H/1H fractionation of a chlorination step in the technical synthesis. In contrast, DDD formed by reductive degradation was strongly depleted at the same position, which was due to the incorporation of 2H-depleted hydride equivalents during reductive degradation. Thus, intramolecular isotope distributions give mechanistic information on reaction pathways, and explain a puzzling difference in the whole-molecule 2H/1H ratio between DDT and DDD. In general, our results highlight that intramolecular isotope distributions are essential to interpret whole-molecule isotope ratios. Intramolecular isotope information allows distinguishing pathways of DDD formation, which is important to identify polluters or to assess DDT turnover in the environment. Because intramolecular isotope data directly reflect isotope fractionation of individual chemical reactions, they are broadly applicable to elucidate transformation pathways of smallbioactive molecules in chemistry, physiology and environmental science.
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| 5. |
- Fernandes, Alwyn R., et al.
(författare)
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Recommended terms and abbreviations for polychlorinated alkanes (PCAs) as the predominant component of chlorinated paraffins (CPs)
- 2023
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Ingår i: TrAC. Trends in analytical chemistry. - : Elsevier. - 0165-9936 .- 1879-3142. ; 169
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Forskningsöversikt (refereegranskat)abstract
- Despite several decades of study, ambiguities persist in terms used to express environmental and biotic occurrences of polychlorinated alkanes (PCAs), the main ingredient of chlorinated paraffins (CPs). This can lead to misinterpretation of data between analytical chemists, toxicologists, risk assessors/managers and regulators. The terms recommended here to harmonise reporting and reduce ambiguity use the conventional definition of PCAs - linear chlorinated alkanes (typically, C≥10) with one chlorine per carbon, although some evidence of multiple chlorination exists. Other recommendations include.● reporting the “Sum of measured PCAs” because “Total PCAs” is currently unquantifiable.●reporting individual chain lengths, e.g., ΣPCAs-C11, ΣPCAs-C13, allows easier comparability and allows toxicology and risk assessment to consider different PCA combinations.● maintain studies on individual PCAs in order to better characterise chemical, environmental and health risk behaviour.The terms could be extended in future to assimilate new findings on individual PCAs, multiple chlorination and chirality.
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| 6. |
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| 7. |
- Hauff, Simone, et al.
(författare)
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Structure and absolute configuration of an unsaturated anteiso fatty acid from Bacillus megaterium
- 2010
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Ingår i: Journal of Chromatography A. - : Elsevier B.V.. - 0021-9673 .- 1873-3778. ; 1217:10, s. 1683-7
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Tidskriftsartikel (refereegranskat)abstract
- Gas chromatography in combination with electron ionization mass spectrometry (GC/EI-MS) was used to determine the fatty acids of a membrane lipid from Bacillus megaterium. Special attention was put on the structure and absolute configuration of a monoenoic fatty acid previously described in this sample. GC/EI-MS operated in the selected ion monitoring mode was used to determine twelve fatty acids in the bacterium. Methyl esters were prepared to verify the presence of a 14-methylhexadecenoic acid (a17:1) isomer. The position of the double bond of the a17:1 isomer and four further monoenoic fatty acids was elucidated by means of their picolinyl esters produced by the transesterification of the phospholipid. For the a17:1 isomer, the double bond was located between C-5 and C-6. Silver ion liquid chromatography was used to verify that the double bond was in cis-configuration. The bacterial 14-methylhexadec-5-enoic acid (a17:1Delta5) is chiral due to the stereogenic C-14 carbon. Initial enantioselective measurements were carried out with isomers of a17:1Delta5 which were available in form of racemic and (S)-enantiopure cis- and trans-isomers of a17:1Delta12 previously synthesized. The cis-a17:1Delta12 enantiomers were partly resolved on a chiral stationary phase coated with 50% heptakis(6-O-tert.-butyldimethylsilyl-2,3-di-O-methyl)-beta-cyclodextrin in OV-1701 (beta-TBDM). However, resolution of the enantiomers of the trans-isomer of a17:1Delta12 failed. Only one peak was also observed for the a17:1Delta5 isomer from B. megaterium. Thus, it remained unclear whether the compound a17:1Delta5 was racemic or enantiopure in the sample. To clarify this point, we separated the cis-monoenoic fraction from the saturated fatty acids. Then, the monoenoic fraction was hydrogenated in order to transform a17:1Delta5 into 14-methylhexadecanoic acid (a17:0). This chiral fatty acid was known to be sufficiently enantioseparated on the beta-TBDM column and was found to be (S)-enantiopure in the sample. Hence, these measurements verified that the B. megaterium sample contained enantiopure (S)-a17:1Delta5.
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| 8. |
- Jenske, Ramona, et al.
(författare)
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Impact of free hydroxylated and methyl-branched fatty acids on the organization of lipid membranes
- 2008
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Ingår i: Chemistry and Physics of Lipids. - : Elsevier. - 0009-3084 .- 1873-2941. ; 154:1, s. 26-32
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Tidskriftsartikel (refereegranskat)abstract
- Differential scanning calorimetry (DSC) has been applied to study the effect of free hydroxylated and methyl-branched fatty acids on the physico-chemical properties of lipid membranes. First, the impact of free hydroxy fatty acids (HFAs) on dimyristoylphosphatidylcholine (DMPC) model membranes was monitored only as a function of chain length and position of the attached hydroxyl group. Second, racemic vs. enantiopure anteiso fatty acids (AFAs) and HFAs were investigated to address the question of which role does a fatty acid's chirality play on its membrane pertubing effect.The DSC thermograms revealed that the main gel to liquid–crystalline phase transition of the DMPC bilayers which results in a disordering effect of the lipid hydrocarbon chains was affected in different ways depending on the nature of the incorporated fatty acid. Long-chain 2- and 3-HFAs stabilized the gel phase by reducing the phase transition temperature (Tm), whereas short-chain HFAs and long-chain HFAs with the hydroxy group remote from the head group stabilized the more disordered liquid–crystalline state. Additionally, we observed that enantiopure (S)-14-methylhexadecanoic acid ((S)-a17:0) and (R)-2-hydroxy octadecanoic acid and the corresponding racemates had contrary effects upon incorporation into DMPC bilayers. In both cases, the pure enantiomers alleviated the liquid–crystalline state of the biological model membrane.
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| 9. |
- Kaffarnik, Stefanie, et al.
(författare)
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Two-Dimensional P-31,H-1 NMR Spectroscopic Profiling of Phospholipids in Cheese and Fish
- 2013
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 61:29, s. 7061-7069
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Tidskriftsartikel (refereegranskat)abstract
- Phospholipids (PLs) comprise an important lipid class in food because of their technological use as emulsifiers and their nutritional value. This study used one-dimensional P-31 NMR and two-dimensional (2D) P-31,H-1 COSY NMR spectroscopy for the determination of the PL composition of cheese and fish after liquid liquid enrichment. This extraction step enabled the identification of 10 PLs in cheese and 9 PLs in fish by 2D P-31,H-1 NMR. Variations in the P-31 shifts indicated differences in the fatty acids attached to the individual PLs. The total PL content in cheese fat and fish oil ranged from 0.3 to 0.4% and from 5 to 12%, respectively. Phosphatidylcholine was the most prominent PL in both matrices (up to 6596). Minor PLs (limit of detection = 4 nmol, i.e. 500 mu L of an 8 mu M solution) were identified in forms of phosphatidic acid, lysophosphatidic acid, and phosphatidylglycerol. Specific cross couplings and H-1 fine structures in the 2D P-31,H-1 NMR spectra proved to be valuable for the assignment and verification of known and uncommon PLs in the samples.
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| 10. |
- Kopp, Lena, et al.
(författare)
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Potential Modulation of Inflammation and Physical Function by Combined Probiotics, Omega-3 Supplementation and Vitamin D Supplementation in Overweight/Obese Patients with Chronic Low-Grade Inflammation : A Randomized, Placebo-Controlled Trial
- 2023
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Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 24:10
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Tidskriftsartikel (refereegranskat)abstract
- Obesity is characterized by low-grade inflammation and increased gut permeability. Here, we aim to evaluate the effect of a nutritional supplement on these parameters in subjects with overweight and obesity. A double-blinded, randomized clinical trial was conducted in 76 adults with overweight or obesity (BMI 28 to 40) and low-grade inflammation (high-sensitivity C-reactive protein (hs-CRP) between 2 and 10 mg/L). The intervention consisted of a daily intake of a multi-strain probiotic of Lactobacillus and Bifidobacterium, 640 mg of omega-3 fatty acids (n-3 FAs), and 200 IU of vitamin D (n = 37) or placebo (n = 39), administered for 8 weeks. hs-CRP levels did not change post-intervention, other than an unexpected slight increase observed in the treatment group. Interleukin (IL)-6 levels decreased in the treatment group (p = 0.018). The plasma fatty acid (FA) levels of the arachidonic acid (AA)/eicosapentaenoic acid (EPA) ratio and n-6/n-3 ratio (p < 0.001) decreased, and physical function and mobility improved in the treatment group (p = 0.006). The results suggest that hs-CRP may not be the most useful inflammatory marker, but probiotics, n-3 FAs, and vitamin D, as non-pharmaceutical supplements, may exert modest effects on inflammation, plasma FA levels, and physical function in patients with overweight and obesity and associated low-grade inflammation.
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