| 1. |
- Olofsson, Sven-Olof, 1947, et al.
(författare)
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Lipid droplets as dynamic organelles connecting storage and efflux of lipids.
- 2008
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Ingår i: Biochimica et biophysica acta. - : Elsevier BV. - 0006-3002. ; 1791:6, s. 448-458
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Tidskriftsartikel (refereegranskat)abstract
- Neutral lipids are stored in the cytosol in so-called lipid droplets. These are dynamic organelles with neutral lipids as the core surrounded by a monolayer of amphipathic lipids (phospholipids and cholesterol) and specific proteins (PAT proteins and proteins involved in the turnover of lipids and in the formation and trafficking of the droplets). Lipid droplets are formed at microsomal membranes as primordial droplets with a diameter of 0.1-0.4 microm and increase in size by fusion. In this article, we review the assembly and fusion of lipid droplets, and the processes involved in the secretion of triglycerides. Triglycerides are secreted from cells by two principally different processes. In the mammary gland, lipid droplets interact with specific regions of the plasma membrane and bud off with an envelope consisting of the membrane, to form milk globules. In the liver and intestine, very low-density lipoproteins (VLDL) and chylomicrons are secreted by using the secretory pathway of the cell. Finally, we briefly review the importance of lipid droplets in the development of insulin resistance and atherosclerosis.
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| 2. |
- Shao, Yangzhen, 1981, et al.
(författare)
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A mouse model reveals an important role for catecholamine-induced lipotoxicity in the pathogenesis of stress-induced cardiomyopathy.
- 2013
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Ingår i: European journal of heart failure. - : Wiley. - 1879-0844 .- 1388-9842. ; 15:1, s. 9-22
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Tidskriftsartikel (refereegranskat)abstract
- AimStress-induced cardiomyopathy (SIC), also known as takotsubo cardiomyopathy, is an acute cardiac syndrome with substantial morbidity and mortality. The unique hallmark of SIC is extensive ventricular dysfunction (akinesia) involving apical segments with preserved function in basal segments. Adrenergic overstimulation plays an important role in initiating SIC, but the pathomechanisms involved are unknown. We tested the hypothesis that excessive catecholamines cause perturbation of myocardial lipid metabolism and that cardiac lipotoxicity is responsible for the pathogenesis of SIC. METHODS AND RESULTS: A single dose injection of isoprenaline (ISO; 400 mg/kg) induced SIC-like regional akinesia in mice. Oil red O staining revealed severe lipid accumulation in the heart 2 h post-ISO. Both intramyocardial lipid accumulation and cardiac function were normalized within 1 week post-ISO and no significant amount of fibrosis was detected. We found that gene expression of lipid importers and exporters (ApoB lipoprotein) was depressed 2 h post-ISO. These results were confirmed by similar findings in SIC patients and in ISO/patient serum-stressed HL-1 cardiomyocytes. Moreover, overexpression of ApoB in the heart was found to protect against the development of ISO-induced cardiac toxicity and cardiac dysfunction. We also found that ISO-induced intramyocardial lipid accumulation caused electrophysiological disturbance and stunning in ISO/patient serum-stressed HL-1 cardiomyocytes. CONCLUSIONS: The present study demonstrates that lipotoxicity is closely associated with catecholamine-induced myocardial dysfunction, including neurogenic stunning, metabolic stunning, and electrophysiological stunning. Cardiac lipotoxicity may originate from direct inhibition of myocardial ApoB lipoprotein and subsequent decreased lipid export, caused by supraphysiological levels of catecholamines.
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| 3. |
- Stiernstedt, Fredrik, 1981-
(författare)
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The voices we trust : Public trust in news and information about COVID-19 on Swedish Radio
- 2021
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Ingår i: Radio Journal. - : Intellect Ltd.. - 1476-4504 .- 2040-1388. ; 19:2
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Tidskriftsartikel (refereegranskat)abstract
- This article explores the question of trust in news and information about the COVID-19 pandemic. The focus of the article is on trust in radio news and the data are collected in Sweden during spring 2020. Two questions are asked: (1) to what extent do people in Sweden express trust in the radio as a medium, and radio news and information as a form of content? (2) How do people themselves explain and discuss their trust in the radio as a medium and in radio news and information? The article draws on both survey data and qualitative interviews in answering these questions. The results show that radio, together with television, is the most trusted medium in the population but that there are differences in the extent of trust within the population that are related to age, economic status and political affiliation. The qualitative interviews showed that the specificities of how radio is organized and the form and mode of expression of radio news can help explain the high trust in the radio medium during the COVID-19 pandemic.
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| 4. |
- Wang, Xiaodi, 1981-, et al.
(författare)
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Synthesis of uniform quasi-octahedral CeO2 mesocrystals via a surfactant-free route
- 2011
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Ingår i: Journal of nanoparticle research. - : Springer Science and Business Media LLC. - 1388-0764 .- 1572-896X. ; 13:11, s. 5879-5885
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Tidskriftsartikel (refereegranskat)abstract
- A facile surfactant-free nonaqueous method is presented to prepare uniform quasi-octahedral ceria, CeO 2 , mesocrystals, in which only Ce(NO 3 ) 3 and octanol were used as the reactants at a reaction temperature of 150 °C. CeO 2 sample synthesized using this technique consists of well-dispersed quasi-octahedrons and exhibits an uniform size and morphology. Based on structural characterization, it is proposed that the CeO 2 mesostructure was formed by self-assembly of primary nanocrystals based on unique 3D oriented-attachment mechanism. Optical characterization exhibited a strong quantum confinement, revealing small size of primary nanocrystals. The thermal stability and UV–Vis study reveal CeO 2 mesocrystal has various potential for high temperature applications and optical apparatus applications.
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| 5. |
- Bonini, Tiziano, et al.
(författare)
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Radio formats and social media use in Europe : 28 case studies of public service practice
- 2014
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Ingår i: Radio Journal. - : Intellect Ltd.. - 1476-4504 .- 2040-1388. ; 12:1-2, s. 89-109
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this article is to report, summarize and spread the results of a largescale European research project funded by EBU Radio in 2011 to map best practices in social media and European public radio, focusing on the way successful public service radio formats have incorporated social media in their production flow. The programmes have been selected for one of the following reasons: programmes that are audience leaders in their country, use innovative radio language or are youthoriented productions. The survey has been carried out by a team of ten European researchers from seven countries on a sample of 28 public radio programmes analysed for two months between January and February 2011. The research team attempted to answer the empirical question: ‘How social media are used by public service?’. Are there some common threads and shared practices among successful programmes in different countries? The team adopted an empirical approach based on social media content analysis and interviews with radio producers. This article will present the main results of this empirical research project. It will conclude with practical guidelines for public radio production and social media innovation.
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| 6. |
- Zhou, Qiongyu, et al.
(författare)
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Corrosion behavior of Hf0.5 Nb0.5 Ta0.5 Ti1.5 Zr refractory high-entropy in aqueous chloride solutions
- 2019
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Ingår i: Electrochemistry Communications. - : Elsevier BV. - 1388-2481. ; 98, s. 63-68
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Tidskriftsartikel (refereegranskat)abstract
- The Hf0.5Nb0.5Ta0.5Ti1.5Zr refractory high-entropy alloy with excellent corrosion resistance in the 3.5 wt% NaCl solution is identified in this work. This refractory high-entropy alloy exhibits much better general corrosion resistance than that of the 316L stainless steel, due to its corrosion current density being about one fifth of that in the latter. Meanwhile, the pitting potential of Hf0.5Nb0.5Ta0.5Ti1.5Zr reaches an unusually high value of +8.36 V, much higher than that of reported high-entropy alloys. The superior passivity of Hf0.5Nb0.5Ta0.5Ti1.5Zr is accredited to the formation of a single-phase solid solution containing high amount of homogenously distributed passivity-promoting elements, and also the existence of metallic Ta and OH− species in the passive film, which contribute to the high immunity to passive film breakdown.
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| 7. |
- Araya, Zufan, et al.
(författare)
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Metabolism of 25-hydroxyvitamin D3 by microsomal and mitochondrial vitamin D3 25-hydroxylases (CYP2D25 and CYP27A1) : a novel reaction by CYP27A1
- 2003
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Ingår i: Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids. - 1388-1981 .- 1879-2618. ; 1632:1-21-3, s. 40-47
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Tidskriftsartikel (refereegranskat)abstract
- The metabolism of 25-hydroxyvitamin D(3) was studied with a crude mitochondrial cytochrome P450 extract from pig kidney and with recombinant human CYP27A1 (mitochondrial vitamin D(3) 25-hydroxylase) and porcine CYP2D25 (microsomal vitamin D(3) 25-hydroxylase). The kidney mitochondrial cytochrome P450 catalyzed the formation of 1alpha,25-dihydroxyvitamin D(3), 24,25-dihydroxyvitamin D(3) and 25,27-dihydroxyvitamin D(3). An additional metabolite that was separated from the other hydroxylated products on HPLC was also formed. The formation of this 25-hydroxyvitamin D(3) metabolite was dependent on NADPH and the mitochondrial electron transferring protein components. A monoclonal antibody directed against purified pig liver CYP27A1 immunoprecipitated the 1alpha- and 27-hydroxylase activities towards 25-hydroxyvitamin D(3) as well as the formation of the unknown metabolite. These results together with substrate inhibition experiments indicate that CYP27A1 is responsible for the formation of the unknown 25-hydroxyvitamin D(3) metabolite in kidney. Recombinant human CYP27A1 was found to convert 25-hydroxyvitamin D(3) into 1alpha,25-dihydroxyvitamin D(3), 25,27-dihydroxyvitamin D(3) and a major metabolite with the same retention time on HPLC as that formed by kidney mitochondrial cytochrome P450. Gas chromatography-mass spectrometry (GC-MS) analysis of the unknown enzymatic product revealed it to be a triol different from other known hydroxylated 25-hydroxyvitamin D(3) metabolites such as 1alpha,25-, 23,25-, 24,25-, 25,26- or 25,27-dihydroxyvitamin D(3). The product had the mass spectrometic properties expected for 4beta,25-dihydroxyvitamin D(3). Recombinant porcine CYP2D25 converted 25-hydroxyvitamin D(3) into 1alpha,25-dihydroxyvitamin D(3) and 25,26-dihydroxyvitamin D(3). It can be concluded that both CYP27A1 and CYP2D25 are able to carry out multiple hydroxylations of 25-hydroxyvitamin D(3).
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| 8. |
- Rotticci, D., et al.
(författare)
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An active-site titration method for lipases
- 2000
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Ingår i: Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids. - 1388-1981 .- 1879-2618. ; 1483:1, s. 132-140
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Tidskriftsartikel (refereegranskat)abstract
- A method for active-site titration of lipases has been developed based on irreversible inhibition by methyl p-nitrophenyl n-hexylphosphonate. This method was applied to five lipases displaying from minor to pronounced interfacial activation. Soluble and immobilized lipases were successfully titrated in aqueous media. A low concentration of sodium dodecyl sulfate was needed for lipases displaying pronounced interfacial activation. The carrier of some of the immobilized preparations adsorbed part of the produced p-nitrophenolate, This problem could be solved by extracting the p-nitrophenolate after inhibition. The method was extended to apolar organic solvents in the case of immobilized lipase preparations.
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| 9. |
- Svartz, Jesper, 1972-, et al.
(författare)
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Leukotriene C4 synthase homo-oligomers detected in living cells by bioluminescence resonance energy transfer
- 2003
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Ingår i: Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids. - : Elsevier. - 1388-1981 .- 1879-2618. ; 1633:2, s. 90-95
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Tidskriftsartikel (refereegranskat)abstract
- Leukotrienes (LTs) are biologically active compounds derived from arachidonic acid which have important pathophysiological roles in asthma and inflammation. The cysteinyl leukotriene LTC4 and its metabolites LTD4 and LTE4 stimulate bronchoconstriction, airway mucous formation and generalized edema formation. LTC4 is formed by addition of glutathione to LTA4, catalyzed by the integral membrane protein, LTC4 synthase (LTCS). We now report the use of bioluminescence resonance energy transfer (BRET) to demonstrate that LTCS forms homo-oligomers in living cells. Fusion proteins of LTCS and Renilla luciferase (Rluc) and a variant of green fluorescent protein (GFP), respectively, were prepared. High BRET signals were recorded in transiently transfected human embryonic kidney (HEK 293) cells co-expressing Rluc/LTCS and GFP/LTCS. Homo-oligomer formation in living cells was verified by co-transfection of a plasmid expressing non-chimeric LTCS. This resulted in dose-dependent attenuation of the BRET signal. Additional evidence for oligomer formation was obtained in cell-free assays using glutathione S-transferase (GST) pull-down assay. To map interaction domains for oligomerization, GFP/LTCS fusion proteins were prepared with truncated variants of LTCS. The results obtained identified a C-terminal domain (amino acids 114–150) sufficient for oligomerization of LTCS. Another, centrally located, interaction domain appeared to exist between amino acids 57–88. The functional significance of LTCS homo-oligomer formation is currently being investigated.
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| 10. |
- Alves, Marina Amaral, et al.
(författare)
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Systems biology approaches to study lipidomes in health and disease
- 2021
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Ingår i: Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids. - : Elsevier. - 1388-1981 .- 1879-2618. ; 1866:2
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Forskningsöversikt (refereegranskat)abstract
- Lipids have many important biological roles, such as energy storage sources, structural components of plasma membranes and as intermediates in metabolic and signaling pathways. Lipid metabolism is under tight homeostatic control, exhibiting spatial and dynamic complexity at multiple levels. Consequently, lipid-related disturbances play important roles in the pathogenesis of most of the common diseases. Lipidomics, defined as the study of lipidomes in biological systems, has emerged as a rapidly-growing field. Due to the chemical and functional diversity of lipids, the application of a systems biology approach is essential if one is to address lipid functionality at different physiological levels. In parallel with analytical advances to measure lipids in biological matrices, the field of computational lipidomics has been rapidly advancing, enabling modeling of lipidomes in their pathway, spatial and dynamic contexts. This review focuses on recent progress in systems biology approaches to study lipids in health and disease, with specific emphasis on methodological advances and biomedical applications.
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