| 1. |
- Fredlund, E., et al.
(författare)
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Metabolite profiles of the biocontrol yeast Pichia anomala J121 grown under oxygen limitation
- 2004
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Ingår i: Applied Microbiology and Biotechnology. - : Springer. - 0175-7598 .- 1432-0614. ; 64:3, s. 403-409
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Tidskriftsartikel (refereegranskat)abstract
- The biocontrol yeast Pichia anomala J121 prevents mould growth during the storage of moist grain under low oxygen/high carbon dioxide conditions. Growth and metabolite formation of P. anomala was analyzed under two conditions of oxygen limitation: (a) initial aerobic conditions with restricted oxygen access during the growth period and (b) initial microaerobic conditions followed by anaerobiosis. Major intra- and extracellular metabolites were analyzed by high-resolution magic-angle spinning (HR-MAS) NMR and HPLC, respectively. HR-MAS NMR allows the analysis of major soluble compounds inside intact cells, without the need for an extraction step. Biomass production was higher in treatment (a), whereas the specific ethanol production rate during growth on glucose was similar in both treatments. This implies that oxygen availability affected the respiration and not the fermentation of the yeast. Following glucose depletion, ethanol was oxidized to acetate in treatment (a), but continued to be produced in (b). Arabitol accumulated in the culture substrate of both treatments, whereas glycerol only accumulated in treatment (b). Trehalose, arabitol, and glycerol accumulated inside the cells in both treatments. The levels of these metabolites were generally significantly higher in treatment (b) than in (a), indicating their importance for P. anomala during severe oxygen limitation/anaerobic conditions.
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| 2. |
- Chaillou, Thomas, 1985-, et al.
(författare)
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NDUFA4L2 : Connecting metabolic signals and mitochondrial function in cardiac and skeletal muscle
- 2016
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Ingår i: Free Radical Biology & Medicine. - : Elsevier. - 0891-5849 .- 1873-4596. ; 100:Suppl., s. S186-S186
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Tidskriftsartikel (refereegranskat)abstract
- The nuclear-encoded mitochondrial protein NADH dehydrogenase (ubiquinone) 1 alpha subcomplex, 4-like 2 (NDUFA4L2) was recently identified. NDUFAe4L2 is shown to be induced by hypoxia via HIF1α and is thought to inhibit production of mitochondrial reactive oxygen species in fibroblasts exposed to hypoxia. Here the aim was to characterize the role of NDUFA4L2 in the mitochondria-rich tissues skeletal and cardiac muscle. We show hypoxia induced NDUFA4L2 expression in isolated muscle fibers and in cardiomyocytes with full activation after ~3-6 h in hypoxia. The half-maximal O2 level for NDUFA4L2 expression (~4.6 % of ambient O2) suggests sensitivity to changes in O2 tension that occur under physiological conditions (e.g. exercise, moderate ischemia). We identified that the NDUFA4L2 gene promoter has binding sites for transcription factors other than HIF-1α; repetitive sites for PPARα,γ and one for Nrf2. NDUFA4L2 overexpression resulted in functional effects on skeletal and cardiac muscle; e.g. it alters cellular Ca2+ signaling and the expression of Ca2+ handling genes. Further, NDUFA4L2 overexpression reduces muscle mass (~20%), leading to a decreased force production in skeletal muscle. The NDUFA4L2-induced loss of muscle mass was associated with increases in mRNA levels of e.g. MurF1, Mul1, caspase-3 and Bax. Additionally, femoral artery ligation (FAL) induced NDUFA4L2 expression, which correlates with the decreased force production eight days post-FAL in skeletal muscle. Moreover, NDUFA4L2 upregulates antioxidant gene expression and silencing NDUFA4L2 makes cardiac cells less tolerant to hypoxia/re-oxygenation. Our results suggest that NDUFA4L2 expression affects vital functions in muscle cells and at least part of this effect is mediated by a link between NDUFA4L2 and nuclear gene expression. Thus, NDUFA4L2 might act as an integrator of the nutritional, environmental and functional status in muscle cells.
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| 3. |
- Steinz, Maarten M, et al.
(författare)
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Oxidative hotspots on actin promote skeletal muscle weakness in rheumatoid arthritis
- 2019
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Ingår i: JCI Insight. - : American Society for Clinical Investigation (ASCI). - 2379-3708 .- 2324-7703 .- 2325-4556. ; 4:9
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Tidskriftsartikel (refereegranskat)abstract
- Skeletal muscle weakness in patients suffering from rheumatoid arthritis (RA) adds to their impaired working abilities and reduced quality of life. However, little molecular insight is available on muscle weakness associated with RA. Oxidative stress has been implicated in the disease pathogenesis of RA. Here, we show that oxidative posttranslational modifications of the contractile machinery targeted to actin result in impaired actin polymerization and reduced force production. Using mass spectrometry, we identified the actin residues targeted by oxidative 3-nitrotyrosine (3-NT) or malondialdehyde (MDA) adduct modifications in weakened skeletal muscle from mice with arthritis and patients afflicted by RA. The residues were primarily located in 3 distinct regions positioned at matching surface areas of the skeletal muscle actin molecule from arthritic mice and patients with RA. Moreover, molecular dynamics simulations revealed that these areas, here coined "hotspots," are important for the stability of the actin molecule and its capacity to generate filaments and interact with myosin. Together, these data demonstrate how oxidative modifications on actin promote muscle weakness in RA patients and may provide novel leads for targeted therapeutic treatment to improve muscle function.
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