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Platanetin and 7-iodo-acridone-4-carboxylic acid are not specific inhibitors of respiratory NAD(P)H dehydrogenases in potato tuber mitochondria

Progress in understanding the role of NAD(P)H oxidation in plant respiration is restricted by the lack of access to specific inhibitors of each of the unknown number of NAD(P)H dehydrogenases in the inner mitochondrial membrane. Platanetin (3,5,7,8-tetrahydroxy-6-isoprenyl flavone) is known to be an inhibitor of external NADH oxidation by plant mitochondria, while 7-iodo-acridone-4-carboxylic acid

The NADH-binding subunit of respiratory chain complex I is nuclear-encoded in plants and identified only in mitochondria

In higher plants, genes for subunits of respiratory chain complex I (NADH:ubiquinone oxidoreductase) have so far been identified solely in organellar genomes. At least nine subunits are encoded by the mitochondrial DNA and 11 homologues by the plastid DNA. One of the 'key' components of complex I is the subunit binding the substrate NADH. The corresponding gene for the mitochondrial subunit has no

Ubiquinone-1 induces external deamino-NADH oxidation in potato tuber mitochondria

The addition of ubiquinone-1 (UQ-1) induced Ca2+-independent oxidation of deamino-NADH and NADH by intact potato (Solanum tuberosum L. cv Bintje) tuber mitochondria. The induced oxidation was coupled to the generation of a membrane potential. Measurements of NAD+-malate dehydrogenase activity indicated that the permeability of the inner mitochondrial membrane to NADH and deamino-NADH was not alter

Isolation of the rotenome-sensitive NADH-ubiquinone reductase (complex I) from red beet mitochondria

Complex 1 of the respirator) chain (EC 1.6.531, measured as NADH-duroquinone and NADH-ubiquinone, reductase activities, was isolated from purified red beetroot (Beta vulgaris L.I mitochondria. The mitochondria were disrupted by freeze-thawing and inner membrane vesicles were pelleted. After solubilization of the vesicles with Triton X-100, the enzyme complex was purified 11-fold (compared to the a

NAD(P)H-ubiquinone oxidoreductases in plant mitochondria

Plant (and fungal) mitochondria contain multiple NAD(P)H dehydrogenases in the inner membrane all of which are connected to the respiratory chain via ubiquinone. On the outer surface, facing the intermembrane space and the cytoplasm, NADH and NADPH are oxidized by what is probably a single low-molecular-weight, nonproton-pumping, unspecific rotenone-insensitive NAD(P)H dehydrogenase. Exogenous NAD

Purification of a rotenone-insensitive NAD(P)H dehydrogenase from the inner surface of the inner membrane of red beetroot mitochondria

The soluble fraction of disrupted red beetroot mitochondria was resolved by anion-exchange chromatography. Three NADH-oxidising activities were found, including one duroquinone reductase oxidising both NADH and NADPH. This NAD(P)H-duroquinone reductase, which we assign as the internal rotenone-insensitive NAD(P)H dehydrogenase, was further purified by affinity chromatography into a 26 kDa polypept

Properties of submitochondrial particles from plant mitochondria : generation, surface characteristics and NAD(P)H oxidation

Purified mitochondria isolated from potato (Solanum tuberosum L. cv. Bintje) tuber, Jerusalem artichoke (Helianthus tuberosu L.) tuber and rat liver were disrupted at different pH and different EDTA and MgCl2 concentrations either by French Press treatment or by sonication. The submitochondrial particles (SMP) were isolated by differential centrifugation and polarity estimated by the latency of cy

Oxidation of external NAD(P)H by purified mitochondria from fresh and aged red beetroots (Beta vulgaris L.)

Mitochondria were isolated from fresh beetroots (Beta vulgaris L. cvs Rubria and Nina) by differential centrifugation followed by Percoll gradient centrifugation. These purified mitochondria oxidized external NADH, although relatively slowly (20-40 versus 100-120 nanomoles oxygen per minute times milligram protein for NADH and succinate oxidation, respectively), with respiratory control ratios of

Effect of calcium ions and inhibitors on internal NAD(P)H dehydrogenases in plant mitochondria

Both the external oxidation of NADH and NADPH in intact potato (Solanum tuberosum L. cv. Bintje) tuber mitochondria and the rotenone-insensitive internal oxidation of NADPH by inside-out submitochondrial particles were dependent on Ca2+. The stimulation was not due to increased permeability of the inner mitochondrial membrane. Neither the membrane potential nor the latencies of NAD+-dependent and

Component of the alternative oxidase localized to the matrix surface of the inner membrane of plant mitochondria

In mitoplasts from Arum maculatum spadices, succinate dehydrogenase (EC 1.3.99.1) and the alternative, cyanide-resistant oxidase activity (measured as m-chlorobenzhydroxamic acid-sensitive duroquinol oxidation) was unaffected by treatment with trypsin. In contrast, when 85% inside-out submitochondrial particles were treated with trypsin the alternative oxidase activity was inhibited by about 50% a

NADP-utilizing enzymes in the matrix of plant mitochondria

Purified potato tuber (Solanum tuberosum L. cv Bintje) mitochondria contain soluble, highly latent NAD+- and NADP+-isocitrate dehydrogenases, NAD+- and NADP+-malate dehydrogenases, as well as an NADPH-specific glutathione reductase (160, 25, 7200, 160, and 16 nanomoles NAD(P)H per minute and milligram protein, respectively). The two isocitrate dehydrogenase activities, but not the two malate dehyd

Metalloproteases and serineproteases are involved in the cleavage of the two tumour necrosis factor (TNF) receptors to soluble forms in the myeloid cell lines U-937 and THP-1

The proteolytic processing of the two TNF receptors (TNF-R55 and TNF-R75) into soluble forms was investigated in the myeloid cell lines U-937 and THP-1. Phorbol myristate acetate (PMA) rapidly stimulated release of soluble forms of both TNF-receptors. Incubations were made with PMA and protease inhibitors directed against different target protease groups. The serineprotease inhibitors TPCK and dic

Smoking and the risk of LADA : Results from a Swedish population-based case-control study

OBJECTIVE: Smoking is an established risk factor for type 2 diabetes. In contrast, it has been proposed that smoking may reduce the risk of latent autoimmune diabetes in adults (LADA), but studies are scarce. We aimed to study the impact of smoking on LADA and type 2 diabetes risks. RESEARCH DESIGN AND METHODS: We used data from a Swedish case-control study including incident case patients with LA

Auditory temporal grouping in newborn infants

Adults normally perceive auditory scenes in terms of sound patterns emitted by concurrently active sources. Thus pattern formation is an important process of auditory object perception. The aim of the present study was to determine whether neonates group sounds by repeating pitch patterns. Standard ("S"; p = 80%) and deviant tones ("D", p = 20%) differing only in pitch were delivered either in a r

Neural Progenitor Cells in malignancy and injury of the brain. A Trojan Horse fro gliomas?

Popular Abstract in Swedish Gliom är en familj av hjärntumörer som är graderade beroende på hur snabbt och på vilket sätt de växer. Grad IV även kallad glioblastoma multiforme, är den mest elakartade av dessa. Patienter har en medelöverlevnadsprognos på ca 12 månader med behandling, såsom kirurgi, kemo- och strålningsterapi. Tumörerna är heterogena, vilket innebär att celler har flera typer av mutGliomas are neoplasms arising in the central nervous system (CNS), and constitute the most common primary brain tumor. They are classified depending on the grade and morphology, from grade I, pilocytic astrocytoma, to grade IV, glioblastoma multiforme (GBM). Glioblastomas constitute a great challenge in treatment due to their disseminating nature. Classical treatments such as surgery, radiation th

Anaerobic batch co-digestion of sisal pulp and fish wastes

Co-digestion of various wastes has been shown to improve the digestibility of the materials and biogas yield. Batchwise digestion of sisal pulp and fish waste was studied both with the wastes separately and with mixtures in various proportions. While the highest methane yields from sisal pulp and fish waste alone were 0.32 and 0.39 m(3) CH4/kg volatile solids (VS), respectively, at total solid (TS