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| 2. |
- Agius, Stephanie C, et al.
(författare)
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NAD(P) turnover in plant mitochondria
- 2001
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Ingår i: Australian Journal of Plant Physiology. - 0310-7841. ; 28:6, s. 461-470
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Tidskriftsartikel (refereegranskat)abstract
- An analytical procedure based on alkaline extraction and HPLC analysis was adapted for quantification of pyridine nucleotides in plant mitochondria. The amounts of NAD and NADP extracted from seven different species varied from 1.0 to 3.7 and 0 to 0.5 nmol (mg protein) –1 , respectively. Although NADP was found in four species, its reduced form was in all cases below the detection limit of 0.1 nmol (mg protein) –1 . The NAD pool was mainly oxidized in the absence of substrates. However, oxidation of substrates followed by anaerobiosis caused 50–92% NAD pool reduction, indicating that the majority of the NAD+ was metabolically active. The NAD reduction level in potato tuber mitochondria oxidizing malate varied with assay conditions. The highest level of reduction (>80%) was reached at anaerobiosis, at pH 6.5 and 7.2, conditions favouring malic enzyme (ME), whereas the lowest reduction level (0%) was observed at pH 7.5, conditions favouring malate dehydrogenase (MDH). Mitochondria incubated at 0°C without respiratory substrate showed a loss of endogenous NAD + which correlated with a decline in the rate of oxidation of NAD+ -linked substrates. The lost NAD+ was mainly recovered as breakdown products in both the surrounding medium and the mitochondria. When submitochondrial fractions were incubated with NAD + or NADP + , the highest rate of NAD(P)+metabolism was detected in the outer membrane fraction. The metabolites detected, adenosine monophosphate (AMP), nicotinamide mononucleotide (NMN) and adenosine, imply that several enzymes involved in pyridine nucleotide degradation, including an NAD pyrophosphatase, are localized to the outer membrane.
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| 3. |
- Agius, Stephanie C, et al.
(författare)
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The internal rotenone-insensitive NADPH dehydrogenase contributes to malate oxidation by potato tuber and pea leaf mitochondria
- 1998
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317. ; 104:3, s. 329-336
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Tidskriftsartikel (refereegranskat)abstract
- Inside-out submitochondrial particles from both potato (Solanum tuberosum L. cv. Bintje) tubers and pea (Pisum sativum L. cv. Oregon) leaves possess three distinct dehydrogenase activities: Complex I catalyzes the rotenone-sensitive oxidation of deamino-NADH, NDin(NADPH) catalyzes the rotenone-insensitive and Ca2+-dependent oxidation of NADPH and NDin(NADH) catalyzes the rotenone-insensitive and Ca2+-independent oxidation of NADH. Diphenylene iodonium (DPI) inhibits complex I, NDin(NADPH) and NDin (NADH) activity with a Ki of 3.7, 0.17 and 63 µM, respectively, and the 400-fold difference in Ki between the two NDin made possible the use of DPI inhibition to estimate NDin (NADPH) contribution to malate oxidation by intact mitochondria. The oxidation of malate in the presence of rotenone by intact mitochondria from both species was inhibited by 5 µM DPI. The maximum decrease in rate was 10–20 nmol O2 mg-1 min-1. The reduction level of NAD(P) was manipulated by measuring malate oxidation in state 3 at pH 7.2 and 6.8 and in the presence and absence of an oxaloacetate-removing system. The inhibition by DPI was largest under conditions of high NAD(P) reduction. Control experiments showed that 125 µM DPI had no effect on the activities of malate dehydrogenase (with NADH or NADPH) or malic enzyme (with NAD+ or NADP+) in a matrix extract from either species. Malate dehydrogenase was unable to use NADP+ in the forward reaction. DPI at 125 µM did not have any effect on succinate oxidation by intact mitochondria of either species. We conclude that the inhibition caused by DPI in the presence of rotenone in plant mitochondria oxidizing malate is due to inhibition of NDin(NADPH) oxidizing NADPH. Thus, NADP turnover contributes to malate oxidation by plant mitochondria.
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| 4. |
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| 5. |
- Altgärde, Noomi, 1983, et al.
(författare)
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Immobilization of chondroitin sulfate to lipid membranes and its interactions with ECM proteins
- 2013
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier BV. - 1095-7103 .- 0021-9797. ; 390:1, s. 528-266
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Tidskriftsartikel (refereegranskat)abstract
- Glycosaminoglycans (GAGs) in the extracellular matrix (ECM) have multiple functions in tissues including providing support, mediating cell division and differentiation, and taking part in important interactions with proteins, e.g. growth factors. Studying GAG related interactions is inherently difficult and requires suit- able interaction platforms. We show two strategies to covalently couple the GAG chondroitin sulfate (CS) to supported lipid bilayers (SLBs), either by (a) activating carboxy-functionalized phospholipids in the lipid bilayer, followed by the addition of hydrazide-functionalized CS, or by (b) activating naturally occurring carboxyl groups on CS prior to addition to an amino-functionalized SLB. Bilayer formation and subsequent immobilization was followed in real-time using the Quartz Crystal Microbalance with Dissipation monitor- ing, a technique that provides unique information when studying highly hydrated molecular films. The two strategies yielded thin CS films (in the nanometer range) with similar viscoelastic properties. Fluidity of the lipid bilayer was retained when CS was coupled. The application of the CS interaction platform was exemplified for type I collagen and the bone inducing growth factor bone morphogenetic protein-2 (BMP-2). The addition of collagen to immoblized CS resulted in soft layers whereas layers formed by addition of BMP-2 were denser, independent on the immobilization strategy used.
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| 6. |
- Altgärde, Noomi, 1983, et al.
(författare)
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Mucin-like region of herpes simplex virus type 1 attachment protein gC modulates the virus-glycosaminoglycan interaction.
- 2015
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 290:35, s. 21473-21485
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Tidskriftsartikel (refereegranskat)abstract
- Glycoprotein C (gC) mediates the attachment of herpes simplex virus type 1 (HSV-1) to susceptible host cells by interacting with glycosaminoglycans (GAGs) on the cell surface. gC contains a mucin-like region located near the GAG-binding site, which may affect the binding activity. Here, we address this issue by studying an HSV-1 mutant lacking the mucin- like domain in gC and the corresponding purified mutant protein (gCΔmuc), in cell culture and GAG-binding assays, respectively. The mutant virus exhibited two functional alterations as compared to native HSV-1, i.e. decreased sensitivity to GAG-based inhibitors of virus attachment to cells, and reduced release of viral particles from the surface of infected cells. Kinetic and equilibrium binding characteristics of purified gC were assessed using surface plasmon resonance-based sensing together with a surface platform consisting of end-on immobilized GAGs. Both native gC and gCΔmuc bound via the expected binding region to chondroitin sulfate and sulfated hyaluronan but not to the non-sulfated hyaluronan, confirming binding specificity. In contrast to native gC, gCΔmuc exhibited a decreased affinity for GAGs and a slower dissociation, indicating that once formed, the gCΔmuc-GAG complex is more stable. It was also found that a larger number of gCΔmuc bound to a single GAG chain, compared to native gC. Taken together, our data suggest that the mucin-like region of HSV-1 gC is involved in the modulation of the GAG-binding activity, a feature of importance both for unrestricted virus entry into the cells and release of newly produced viral particles from infected cells.
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| 7. |
- Altgärde, Noomi, 1983, et al.
(författare)
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Probing the biofunctionality of biotinylated hyaluronan and chondroitin sulfate by hyaluronidase degradation and aggrecan interaction
- 2013
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Ingår i: Acta Biomaterialia. - : Elsevier BV. - 1878-7568 .- 1742-7061. ; 9:9, s. 8158-8166
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Tidskriftsartikel (refereegranskat)abstract
- Molecular interactions involving glycosaminoglycans (GAGs) are important for biological processes in the extracellular matrix (ECM) and at cell surfaces, and also in biotechnological applications. Enzymes in the ECM constantly modulate the molecular structure and the amount of GAGs in our tissues. Specifically, the changeable sulfation patterns of many GAGs are expected to be important in interactions with proteins. Biotinylation is a convenient method for immobilizing molecules to surfaces. When studying interactions at the molecular, cell and tissue level, the native properties of the immobilized molecule, i.e. its biofunctionality, need to be retained upon immobilization. Here, the GAGs hyaluronan (HA) and chondroitin sulfate (CS), and synthetically sulfated derivatives of the two, were immobilized using biotin-streptavidin binding. The degree of biotinylation and the placement of biotin groups (end-on/side-on) were varied. The introduction of biotin groups could have unwanted effects on the studied molecule, but this aspect that is not always straightforward to evaluate. Hyaluronidase, an enzyme that degrades HA and CS in the ECM, was investigated as a probe to evaluate the biofunctionality of the immobilized GAGs, using both quartz crystal microbalance and high-performance liquid chromatography. Our results showed that end-on biotinylated HA was efficiently degraded by hyaluronidase, whereas already a low degree of side-on biotinylation destroyed the degrading ability of the enzyme. Synthetically introduced sulfate groups also had this effect. Hence hyaluronidase degradation is a cheap and easy way to investigate how molecular function is influenced by the introduced functional groups. Binding experiments with the proteoglycan aggrecan emphasized the influence of protein size and surface orientation of the GAGs for in-depth studies of GAG behavior.
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| 8. |
- Hansen, Edward, et al.
(författare)
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Partial melting in amphibolites in a deep section of the Sveconorwegian Orogen, SW Sweden
- 2015
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Ingår i: Lithos. - : Elsevier BV. - 0024-4937. ; 236, s. 27-45
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Tidskriftsartikel (refereegranskat)abstract
- Garnet amphibolite metataxites at the Steningekusten Nature Reserve in southwestern Sweden contain tonalitic patches and veins. Whole rock chemistry suggests that the protoliths were mafic igneous rocks with alkaline affinities. Orthopyroxene megacrysts are present in leucosome in parts of these garnet amphibolites but absent in others. Orthopyroxene megacrysts were formed by vapor-absent melting initiated by incongruent melting of biotite followed by the breakdown of hornblende. The net reaction was Bt + Hbl + PI +/- Qtz <-> Opx + Melt + Cpx + Gt. Melting occurred at pressures of approximately 1 GPa and temperatures which probably exceeded 800 degrees C. Pyroxenes are surrounded by hornblende-quartz symplectites, and hornblende in these coronas has distinctly lower concentrations of (Na + K) and Ti than that in adjacent mesosorne. The hornblende rims formed upon cooling and reaction with crystallizing melt This created a barrier to further reaction thus preserving the orthopyroxene megacrysts. Garnet amphibolite metatexites lacking pyroxene megacrysts have features characteristic of vapor-present melting including lack of peritectic phases predicted by vapor-absent melting reactions, larger amounts of leucosome (14 versus 7%), and less distinct melanosomes. The variation in these migmatites reflects open system behavior, either on a regional scale with the migration of aqueous fluids into the amphibolites or on a local scale with the migration of melt within the amphibolites. Zircons from all units have CL-dark core domains that are dated at 1415-1390 Ma. The core zones are cut and overgrown by CL-dark and CL-bright rims that are dated at 975-965 Ma. The zircon rims are thin in the mesosome but are thicker in the leucosome suggesting that they formed during migmatization. New growth of zircon associated with migmatization at ca. 970 Ma corresponds to the timing of crustal scale partial melting in the deep regions of the Sveconorwegian orogen, synchronous with east-west extension and the intrusion of mafic dykes. If partial melting was driven by an influx of aqueous fluids, they were probably derived from a relatively cool source region, which would indicate tectonic juxtaposition of hotter and cooler terranes. (C) 2015 Elsevier B.V. All rights reserved.
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| 9. |
- Johansson, Robert, et al.
(författare)
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Psychodynamic Guided Self-Help for Adult Depression through the Internet : A Randomised Controlled Trial
- 2012
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:5, s. e38021-
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Background and aims: Psychodynamic psychotherapy (PDT) is an effective treatment for major depressive disorder (MDD), but not all clients with MDD can receive psychotherapy. Using the Internet to provide psychodynamic treatments is one way of improving access to psychological treatments for MDD. The aim of this randomised controlled trial was to investigate the efficacy of an Internet-based psychodynamic guided self-help treatment for MDD. Methods: Ninety-two participants who were diagnosed with MDD according to the Mini-International Neuropsychiatric Interview were randomised to treatment or an active control. The treatment consisted of nine treatment modules based on psychodynamic principles with online therapist contact. The active control condition was a structured support intervention and contained psychoeducation and scheduled weekly contacts online. Both interventions lasted for 10 weeks. The primary outcome measure was the Beck Depression Inventory-II (BDI-II). Results: Mixed-effects model analyses of all randomised participants showed that participants receiving Internet-based PDT made large and superior improvements compared with the active control group on the BDI-II (between-group Cohen’s d = 1.11). Treatment effects were maintained at a 10-month follow-up. Conclusions: Internet-based psychodynamic guided self-help is an efficacious treatment for MDD that has the potential to increase accessibility and availability of PDT for MDD.
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| 10. |
- Kappelhoff, Jan, et al.
(författare)
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Spectroscopic studies on Pr3+ doped YPO4 and LuPO4 upon vacuum ultraviolet (VUV) and synchrotron radiation excitation
- 2022
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Ingår i: Chemical Physics. - : Elsevier BV. - 0301-0104. ; 562
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Tidskriftsartikel (refereegranskat)abstract
- This work concerns the spectroscopic properties of micro- and nanoscale LuPO4:Pr3+ and microscale YPO4:Pr3+ upon excitation by VUV synchrotron radiation at a wide range of energies (5–45 eV) and two different temperatures (7 and 300 K). Both Pr3+ doped host materials show more intense UV-C emission than other Pr3+ phosphors studied earlier at FinEstBeAMS beamline under the same measurement conditions. The various relaxation processes of 5d14f1 → 4f2 interconfigurational transitions of Pr3+ and the difference between both hosts are discussed in detail.
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| 11. |
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