| 1. |
- Alikhani, Nyosha, et al.
(författare)
-
Mitochondria and Alzheimer's disease : amyloid-beta peptide uptake and degradation by the presequence protease, hPreP
- 2009
-
Ingår i: Journal of Bioenergetics and Biomembranes. - : Springer Science and Business Media LLC. - 0145-479X .- 1573-6881. ; 41:5, s. 447-451
-
Tidskriftsartikel (refereegranskat)abstract
- Several lines of evidence suggest mitochondrial dysfunction as a possible underlying mechanism of Alzheimer's disease (AD). Accumulation of the amyloid-beta peptide (Abeta), a neurotoxic peptide implicated in the pathogenesis of AD, has been detected in brain mitochondria of AD patients and AD transgenic mouse models. In vitro evidence suggests that the Abeta causes mitochondrial dysfunction e.g. oxidative stress, mitochondrial fragmentation and decreased activity of cytochrome c oxidase and TCA cycle enzymes. Here we review the link between mitochondrial dysfunctions and AD. In particular we focus on the mechanism for Abeta uptake by mitochondria and on the recently identified Abeta degrading protease in human brain mitochondria.
|
|
| 2. |
- Begun, A., et al.
(författare)
-
Gauge theory : protein topology and dynamics
- 2018
-
Ingår i: Journal of Bioenergetics and Biomembranes. - : SPRINGER/PLENUM PUBLISHERS. - 0145-479X .- 1573-6881. ; 50:6, s. 500-501
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 3. |
- Eriksson, AnnaCarin, et al.
(författare)
-
Characterization of the bifunctional mitochondrial processing peptidase (MPP)/bc1 complex in Spinacia oleracea
- 1996
-
Ingår i: Journal of Bioenergetics and Biomembranes. - 0145-479X .- 1573-6881. ; 28:3, s. 285-292
-
Tidskriftsartikel (refereegranskat)abstract
- The mitochondrial general processing peptidase (MPP) in plant mitochondria constitutes an integral part of the cytochromebc 1 complex of the respiratory chain. Here we present a characterization of this bifunctional complex from spinach leaf mitochondria. The purified MPP/bc 1 complex has a molecular mass of 550 kDa, which corresponds to a dimer. Increased ionic strength results in partial dissociation of the dimer as well as loss of the processing activity. Micellar concentrations of nonionic and zwitterionic detergents stimulate the activity by decreasing the temperature optimum of the processing reaction, whereas anionic detergents totally suppress the activity. MPP is a metalloendopeptidase. Interestingly, hemin, a potent regulator of mitochondrial and cytosolic biogenesis and inhibitor of proteosomal degradation, inhibits the processing activity. Measurements of the processing activity at different redox states of the bc 1 complex show that despite bifunctionality of the MPP/bc 1 complex, there is no correlation between electron transfer and protein processing.
|
|
| 4. |
- Farci, Domenica, et al.
(författare)
-
Isolation and characterization of a main porin from the outer membrane of Salinibacter ruber
- 2022
-
Ingår i: Journal of Bioenergetics and Biomembranes. - : Springer. - 0145-479X .- 1573-6881. ; 54, s. 273-281
-
Tidskriftsartikel (refereegranskat)abstract
- Salinibacter ruber is an extremophilic bacterium able to grow in high-salts environments, such as saltern crystallizer ponds. This halophilic bacterium is red-pigmented due to the production of several carotenoids and their derivatives. Two of these pigment molecules, salinixanthin and retinal, are reported to be essential cofactors of the xanthorhodopsin, a light-driven proton pump unique to this bacterium. Here, we isolate and characterize an outer membrane porin-like protein that retains salinixanthin. The characterization by mass spectrometry identified an unknown protein whose structure, predicted by AlphaFold, consists of a 8 strands beta-barrel transmembrane organization typical of porins. The protein is found to be part of a functional network clearly involved in the outer membrane trafficking. Cryo-EM micrographs showed the shape and dimensions of a particle comparable with the ones of the predicted structure. Functional implications, with respect to the high representativity of this protein in the outer membrane fraction, are discussed considering its possible role in primary functions such as the nutrients uptake and the homeostatic balance. Finally, also a possible involvement in balancing the charge perturbation associated with the xanthorhodopsin and ATP synthase activities is considered.
|
|
| 5. |
- Ferguson, Michael A, et al.
(författare)
-
Increased platelet mitochondrial respiration after cardiac arrest and resuscitation as a potential peripheral biosignature of cerebral bioenergetic dysfunction
- 2016
-
Ingår i: Journal of Bioenergetics and Biomembranes. - : Springer Science and Business Media LLC. - 1573-6881 .- 0145-479X. ; 48:3, s. 269-279
-
Tidskriftsartikel (refereegranskat)abstract
- Cardiac arrest (CA) results in a sepsis-like syndrome with activation of the innate immune system and increased mitochondrial bioenergetics.OBJECTIVE: To determine if platelet mitochondrial respiration increases following CA in a porcine pediatric model of asphyxia-associated ventricular fibrillation (VF) CA, and if this readily obtained biomarker is associated with decreased brain mitochondrial respiration. CA protocol: 7 min of asphyxia, followed by VF, protocolized titration of compression depth to systolic blood pressure of 90 mmHg and vasopressor administration to a coronary perfusion pressure greater than 20 mmHg.PRIMARY OUTCOME: platelet integrated mitochondrial electron transport system (ETS) function evaluated pre- and post-CA/ROSC four hours after return of spontaneous circulation (ROSC). Secondary outcome: correlation of platelet mitochondrial bioenergetics to cerebral bioenergetic function. Platelet maximal oxidative phosphorylation (OXPHOSCI+CII), P < 0.02, and maximal respiratory capacity (ETSCI+CII), P < 0.04, were both significantly increased compared to pre-arrest values. This was primarily due to a significant increase in succinate-supported respiration through Complex II (OXPHOSCII, P < 0.02 and ETSCII, P < 0.03). Higher respiration was not due to uncoupling, as the LEAKCI + CII respiration (mitochondrial respiration independent of ATP-production) was unchanged after CA/ROSC. Larger increases in platelet mitochondrial respiratory control ratio (RCR) compared to pre-CA RCR were significantly correlated with lower RCRs in the cortex (P < 0.03) and hippocampus (P < 0.04) compared to sham respiration. Platelet mitochondrial respiration is significantly increased four hours after ROSC. Future studies will identify mechanistic relationships between this serum biomarker and altered cerebral bioenergetics function following cardiac arrest.
|
|
| 6. |
- Feyziyev, Yashar, et al.
(författare)
-
Electron transfer from Cyt b (559) and tyrosine-D to the S-2 and S-3 states of the water oxidizing complex in photosystem II at cryogenic temperatures
- 2013
-
Ingår i: Journal of Bioenergetics and Biomembranes. - : Springer Science and Business Media LLC. - 0145-479X .- 1573-6881. ; 45:1-2, s. 111-120
-
Tidskriftsartikel (refereegranskat)abstract
- The Mn4CaO5 cluster of photosystem II (PSII) catalyzes the oxidation of water to molecular oxygen through the light-driven redox S-cycle. The water oxidizing complex (WOC) forms a triad with Tyrosine(Z) and P-680, which mediates electrons from water towards the acceptor side of PSII. Under certain conditions two other redox-active components, Tyrosine(D) (Y-D) and Cytochrome b (559) (Cyt b (559)) can also interact with the S-states. In the present work we investigate the electron transfer from Cyt b (559) and Y-D to the S-2 and S-3 states at 195 K. First, Y-D (aEuro cent) and Cyt b (559) were chemically reduced. The S-2 and S-3 states were then achieved by application of one or two laser flashes, respectively, on samples stabilized in the S-1 state. EPR signals of the WOC (the S-2-state multiline signal, ML-S-2), Y-D (aEuro cent) and oxidized Cyt b (559) were simultaneously detected during a prolonged dark incubation at 195 K. During 163 days of incubation a large fraction of the S-2 population decayed to S-1 in the S-2 samples by following a single exponential decay. Differently, S-3 samples showed an initial increase in the ML-S-2 intensity (due to S-3 to S-2 conversion) and a subsequent slow decay due to S-2 to S-1 conversion. In both cases, only a minor oxidation of Y-D was observed. In contrast, the signal intensity of the oxidized Cyt b (559) showed a two-fold increase in both the S-2 and S-3 samples. The electron donation from Cyt b (559) was much more efficient to the S-2 state than to the S-3 state.
|
|
| 7. |
- Gardeström, Per, 1950-, et al.
(författare)
-
The contribution of mitochondria to energetic metabolism in photosynthetic cells
- 1995
-
Ingår i: Journal of Bioenergetics and Biomembranes. - 0145-479X .- 1573-6881. ; 27:4, s. 415-421
-
Tidskriftsartikel (refereegranskat)abstract
- Mitochondria fulfill important functions in photosynthetic cells not only in darkness but also in light. Mitochondrial oxidative phosphorylation is probably the main mechanism to supply ATP for extrachloroplastic functions in both conditions. Furthermore, during photosynthesis mitochondrial electron transport is important for regulation of the redox balance in the cell. This makes mitochondrial function an integral part of a flexible metabolic system in the photosynthetic cell. This flexibility is probably very important in order to allow the metabolism to override disturbances caused by the changing environment which plants are adapted to.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
- Lagerlöf, Olof
(författare)
-
O-GlcNAc cycling in the developing, adult and geriatric brain
- 2018
-
Ingår i: Journal of Bioenergetics and Biomembranes. - : Springer-Verlag New York. - 0145-479X .- 1573-6881. ; 50:3, s. 241-261
-
Tidskriftsartikel (refereegranskat)abstract
- Hundreds of proteins in the nervous system are modified by the monosaccharide O-GlcNAc. A single protein is often O-GlcNAcylated on several amino acids and the modification of a single site can play a crucial role for the function of the protein. Despite its complexity, only two enzymes add and remove O-GlcNAc from proteins, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Global and local regulation of these enzymes make it possible for O-GlcNAc to coordinate multiple cellular functions at the same time as regulating specific pathways independently from each other. If O-GlcNAcylation is disrupted, metabolic disorder or intellectual disability may ensue, depending on what neurons are affected. O-GlcNAc's promise as a clinical target for developing drugs against neurodegenerative diseases has been recognized for many years. Recent literature puts O-GlcNAc in the forefront among mechanisms that can help us better understand how neuronal circuits integrate diverse incoming stimuli such as fluctuations in nutrient supply, metabolic hormones, neuronal activity and cellular stress. Here the functions of O-GlcNAc in the nervous system are reviewed.
|
|
| 11. |
- Magnitsky, Sergey, et al.
(författare)
-
EPR Characterization of Ubisemiquinones and Iron-Sulfur Cluster N2, Central Components of the Energy Coupling in the NADH-Ubiquinone Oxidoreductase (Complex I) In Situ
- 2002
-
Ingår i: Journal of Bioenergetics and Biomembranes. - 1573-6881. ; 34:3, s. 193-208
-
Tidskriftsartikel (refereegranskat)abstract
- The proton-translocating NADH-ubiquinone oxidoreductase (complex I) is the largest and least understood respiratory complex. The intrinsic redox components (FMN and iron-sulfur clusters) reside in the promontory part of the complex. Ubiquinone is the most possible key player in proton-pumping reactions in the membrane part. Here we report the presence of three distinct semiquinone species in complex I in situ, showing widely different spin relaxation profiles. As our first approach, the semiquinone forms were trapped during the steady state NADH-ubiquinone-1 (Q_1) reactions in the tightly coupled, activated bovine heart submitochondrial particles, and were named SQ_Nf (fast-relaxing component), SQ_Ns (slow-relaxing), and SQ_Nx (very slow relaxing). This indicates the presence of at least three different quinone-binding sites in complex I. In the current study, special attention was placed on the SQ_Nf, because of its high sensitivities to Delta ilde{mu}_{H^{ +}} and to specific complex I inhibitors (rotenone and piericidin A) in a unique manner. Rotenone inhibits the forward electron transfer reaction more strongly than the reverse reaction, while piericidine A inhibits both reactions with a similar potency. Rotenone quenched the SQ_Nf signal at a much lower concentration than that required to quench the slower relaxing components (SQ_Ns and SQ_Nx). A close correlation was shown between the line shape alteration of the g_vertical = 2.05 signal of the cluster N2 and the quenching of the SQ_Nf signal, using two different experimental approaches: (1) changing the Delta ilde{mu}_{H^{+}} poise by the oligomycin titration which decreases proton leak across the SMP membrane; (2) inhibiting the reverse electron transfer with different concentrations of rotenone. These new experimental results further strengthen our earlier proposal that a direct spin-coupling occurs between SQ_Nf and cluster N2. We discuss the implications of these findings in connection with the energy coupling mechanism in complex I.
|
|
| 12. |
- Matsson, Mikael, et al.
(författare)
-
The carboxin-binding site on Paracoccus denitrificans succinate:quinone reductase identified by mutation and structure comparison
- 2001
-
Ingår i: Journal of Bioenergetics and Biomembranes. - 1573-6881. ; 33, s. 99-105
-
Tidskriftsartikel (refereegranskat)abstract
- Succinate:quinone reductase catalyzes electron transfer from succinate to quinone in aerobic respiration. Carboxin is a specific inhibitor of this enzyme from several different organisms. We have isolated mutant strains of the bacterium Paracoccus denitrificans that are resistant to carboxin due to mutations in the succinate:quinone reductase. The mutations identify two amino acid residues, His228 in SdhB and Asp89 in SdhD, that most likely constitute part of a carboxin-binding site. This site is in the same region of the enzyme as the proposed active site for ubiquinone reduction. From the combined mutant data and structural information derived from Escherichia coli and Wolinella succinogenes quinol:fumarate reductase, we suggest that carboxin acts by blocking binding of ubiquinone to the active site. The block would be either by direct exclusion of uhiquinone from the active site or by occlusion of a pore that leads to the active site.
|
|
| 13. |
|
|
| 14. |
- Pettersson, Helen, et al.
(författare)
-
Arsenic trioxide and neuroblastoma cytotoxicity.
- 2007
-
Ingår i: Journal of Bioenergetics and Biomembranes. - : Springer Science and Business Media LLC. - 1573-6881 .- 0145-479X. ; 39:1, s. 35-41
-
Forskningsöversikt (refereegranskat)abstract
- The majority of aggressive forms of the childhood tumor neuroblastoma can with current treatment protocols not be cured and possess a major challenge in pediatric oncology. After initial rounds of chemotherapy, surgery and irradiation, which in most cases result in tumor regression, these aggressive neuroblastomas relapse and frequently develop drug resistance. As approximately 50% of the children with neuroblastoma have an aggressive form, there is a compelling demand for new treatment strategies. Arsenic trioxide has the capacity to kill multidrug-resistant neuro-blastoma cells in vitro and in vivo and the drug is currently being evaluated in clinical trials. In this report we discuss the background to the use of arsenic trioxide in cancer therapy and the currently known mechanisms by which arsenic trioxide kills human neuroblastoma cells.
|
|
| 15. |
- Shoshan, MC
(författare)
-
3-Bromopyruvate: targets and outcomes
- 2012
-
Ingår i: Journal of bioenergetics and biomembranes. - : Springer Science and Business Media LLC. - 1573-6881 .- 0145-479X. ; 44:1, s. 7-15
-
Tidskriftsartikel (refereegranskat)
|
|
| 16. |
- Vilela, Wembley R., et al.
(författare)
-
Metabolic dysfunction induced by HFD plus L-NAME preferentially affects hippocampal mitochondria, impacting spatial memory in rats
- 2024
-
Ingår i: Journal of Bioenergetics and Biomembranes. - : SPRINGER/PLENUM PUBLISHERS. - 0145-479X .- 1573-6881.
-
Tidskriftsartikel (refereegranskat)abstract
- High-fat diet-induced metabolic changes are not restricted to the onset of cardiovascular diseases, but also include effects on brain functions related to learning and memory. This study aimed to evaluate mitochondrial markers and function, as well as cognitive function, in a rat model of metabolic dysfunction. Eight-week-old male Wistar rats were subjected to either a control diet or a two-hit protocol combining a high fat diet (HFD) with the nitric oxide synthase inhibitor L-NAME in the drinking water. HFD plus L-NAME induced obesity, hypertension, and increased serum cholesterol. These rats exhibited bioenergetic dysfunction in the hippocampus, characterized by decreased oxygen (O2) consumption related to ATP production, with no changes in H2O2 production. Furthermore, OPA1 protein expression was upregulated in the hippocampus of HFD + L-NAME rats, with no alterations in other morphology-related proteins. Consistently, HFD + L-NAME rats showed disruption of performance in the Morris Water Maze Reference Memory test. The neocortex did not exhibit either bioenergetic changes or alterations in H2O2 production. Calcium uptake rate and retention capacity in the neocortex of HFD + L-NAME rats were not altered. Our results indicate that hippocampal mitochondrial bioenergetic function is disturbed in rats exposed to a HFD plus L-NAME, thus disrupting spatial learning, whereas neocortical function remains unaffected. A two-hit protocol using HFD + L-NAME induces metabolic dysfunction in rats.Spatial memory is impacted in HFD + L-NAME rats.Hippocampal but not neocortex bioenergetics is affected in HFD + L-NAME rats.OPA-1 expression is upregulated in the hippocampus of HFD + L-NAME rats.Cortical calcium dynamics was not affected by HFD + L-NAME.
|
|
| 17. |
- Alveteg, Mattias, et al.
(författare)
-
On the Calculation and Interpretation of Target Load Functions
- 2007
-
Ingår i: Water, Air, & Soil Pollution: Focus. - : Springer Science and Business Media LLC. - 1573-2940 .- 1567-7230. ; 7:1-3, s. 385-390
-
Tidskriftsartikel (refereegranskat)abstract
- In this study critical load functions and target load functions of nitrogen and sulphur deposition with respect to acidity and minimum base cation to aluminium ratio were calculated with the SAFE model using three different averaging strategies: (1) averaging based on current forest generation, (2) averaging based on next generation and (3) averaging based on the entire simulation period. From the results it is evident that although target load calculation and indeed critical load calculation is straight forward, there is a problem in translating a predicted recovery according to the target load calculation back to a site-specific condition. We conclude that a policy strategy for emission reductions that ensures recovery, according to calculated target load functions, is likely to be beneficial from an ecosystem point of view. However, such a strategy may not be sufficient to achieve actual non-violation of the chemical criteria throughout the seasonal or rotational variations. To address this issue we propose a method for calculating dynamic critical loads which ensures that the chosen criteria is not violated.
|
|
