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Electron transport chain mechanism

Nick Lawson, Chung-Han Hsieh, Dana March, Xinnan Wang
Chronic Fatigue Syndrome (CFS) is a debilitating disease characterized by physical and mental exhaustion. The underlying pathogenesis is unknown, but impairments in certain mitochondrial functions have been found in some CFS patients. To thoroughly reveal mitochondrial deficiencies in CFS patients, here we examine the key aspects of mitochondrial function in blood cells from a paired CFS patient-control series. Surprisingly, we discover that in patients the ATP levels are higher and mitochondrial cristae are more condensed compared to their paired controls, while the mitochondrial crista length, mitochondrial size, shape, density, membrane potential, and enzymatic activities of the complexes in the electron transport chain remain intact...
2016: Journal of Nature and Science
Bradley W Abramson, Benjamin Kachel, David M Kramer, Daniel C Ducat
In plants, a limited capacity to utilize or export the end products of the Calvin Benson cycle (CB) from photosynthetically-active source cells to non-photosynthetic sink cells can result in reduced carbon capture, photosynthetic electron transport (PET) and lowered photochemical efficiency. The downregulation of photosynthesis caused by reduced capacity to utilize photosynthate has been termed "sink limitation". Recently, several cyanobacterial and algal strains engineered to over-produce target metabolites have exhibited increased photochemistry suggesting possible source-sink regulatory mechanisms may be involved...
October 13, 2016: Plant & Cell Physiology
Constanze Pinske, R Gary Sawers
Numerous recent developments in the biochemistry, molecular biology, and physiology of formate and H2 metabolism and of the [NiFe]-hydrogenase (Hyd) cofactor biosynthetic machinery are highlighted. Formate export and import by the aquaporin-like pentameric formate channel FocA is governed by interaction with pyruvate formate-lyase, the enzyme that generates formate. Formate is disproportionated by the reversible formate hydrogenlyase (FHL) complex, which has been isolated, allowing biochemical dissection of evolutionary parallels with complex I of the respiratory chain...
October 2016: EcoSal Plus
Theresa Dankowski, Torsten Schröder, Steffen Möller, Xinhua Yu, David Ellinghaus, Florian Bär, Klaus Fellermann, Hendrik Lehnert, Stefan Schreiber, Andre Franke, Christian Sina, Saleh M Ibrahim, Inke R König
BACKGROUND: Ulcerative colitis (UC) is a chronic inflammatory disorder of still unknown pathogenesis. Increasing evidence indicates that alterations in mitochondrial respiration and thus adenosine triphosphate (ATP) production are involved. This may contribute to mucosal energy deficiency and subsequently intestinal barrier malfunction, which is accepted to be a major hallmark of UC. Genetic alterations of the mitochondrial genome are one cause of mitochondrial dysfunction. However, less is known about mitochondrial gene polymorphisms in UC...
October 3, 2016: BMC Gastroenterology
Jarosław Króliczewski, Małgorzata Piskozub, Rafał Bartoszewski, Bożena Króliczewska
The cytochrome b6 f complex occupies an electrochemically central position in the electron-transport chain bridging the photosynthetic reaction center of PS I and PS II. In plants, the subunits of these thylakoid membrane protein complexes are both chloroplast and nuclear encoded. How the chloroplast-encoded subunits of multi-spanning cytochrome b6 are targeted and inserted into the thylakoid membrane is not fully understood. Experimental approaches to evaluate the cytochrome b6 import mechanism in vivo have been limited to bacterial membranes and were not a part of the chloroplast environment...
October 4, 2016: Scientific Reports
Ernesto Cuevasanta, Matías N Möller, Beatriz Alvarez
Hydrogen sulfide (H2S) has been traditionally considered to be a toxic molecule for mammals. However, it can be formed endogenously and exert physiological effects with potential health benefits. H2S can partition two-fold in biological membranes and traverse them rapidly, diffusing between compartments. H2S reactivity has similarities to that of thiols, although it is less nucleophilic than thiols and it can form different products. H2S can react with oxidants derived from the partial reduction of oxygen, but direct scavenging is unlikely to explain H2S protective actions...
September 30, 2016: Archives of Biochemistry and Biophysics
Marta Delgado-Camprubi, Noemi Esteras, Marc Pm Soutar, Helene Plun-Favreau, Andrey Y Abramov
The Parkinson's disease (PD)-related protein F-box only protein 7 (Fbxo7) is the substrate-recognition component of the Skp1-Cullin-F-box protein E3 ubiquitin ligase complex. We have recently shown that PD-associated mutations in Fbxo7 disrupt mitochondrial autophagy (mitophagy), suggesting a role for Fbxo7 in modulating mitochondrial homeostasis. Here we report that Fbxo7 deficiency is associated with reduced cellular NAD(+) levels, which results in increased mitochondrial NADH redox index and impaired activity of complex I in the electron transport chain...
September 30, 2016: Cell Death and Differentiation
Marisol Orozco-Ibarra, Jazmín García-Morales, Francisco José Calvo-Silva, Francisca Fernández-Valverde, Norma Serrano-García
BACKGROUND: Mitochondrial dysfunction is involved in neurodegenerative diseases, such as Huntington's disease (HD). 3-Nitropropionic acid (3-NP) is a mitochondrial toxin that specifically inhibits complex II of the electron transport chain (ETC) and is used to generate an experimental model of HD. OBJECTIVE: To study the effect of fish liver oil (FO) over the mitochondrial dysfunction induced via partial ETC inhibition by 3-NP. METHODS: This study was performed in rats and consisted of two phases: (i) administration of increasing doses of 3-NP and (ii) administration of FO for 14 days before to 3-NP...
September 28, 2016: Nutritional Neuroscience
Neha Kapila, Ankita Sharma, Amit Kishore, Monika Sodhi, Pawan K Tripathi, Ashok K Mohanty, Manishi Mukesh
The present study aims to identify the heat responsive genes and biological pathways in heat stressed buffalo mammary epithelial cells (MECs). The primary mammary epithelial cells of riverine buffalo were exposed to thermal stress at 42°C for one hour. The cells were subsequently allowed to recover at 37°C and harvested at different time intervals (30 min to 48 h) along with control samples (un-stressed). In order to assess the impact of heat stress in buffalo MECs, several in-vitro cellular parameters (lactate dehydrogenase activity, cell proliferation assay, cellular viability, cell death and apoptosis) and transcriptional studies were conducted...
2016: PloS One
Ngonidzashe B Madungwe, Netanel F Zilberstein, Yansheng Feng, Jean C Bopassa
Reactive oxygen species (ROS) generation has been implicated in many pathologies including ischemia/reperfusion (I/R) injury. This led to multiple studies on antioxidant therapies to treat cardiovascular diseases but paradoxically, results have so far been mixed as ROS production can be beneficial as a signaling mechanism and in cardiac protection via preconditioning interventions. We investigated whether the differential impact of increased ROS in injury as well as in protection could be explained by their site of production on the mitochondrial electron transport chain...
2016: American Journal of Cardiovascular Disease
Tingting Xie, Dan Chen, Jian Wu, Xiaorong Huang, Yifan Wang, Keli Tang, Jiayang Li, Mengxiang Sun, Xiongbo Peng
Most pentatricopeptide repeat (PPR) proteins are involved in organelle post-transcriptional processes, including RNA editing. The PPR proteins include the PLS subfamily, containing characteristic triplets of P, L, and S motifs; however, their editing mechanisms and roles in developmental processes are not fully understood. In this study, we isolated the Arabidopsis thaliana Growing slowly 1 (AtGRS1) gene and showed that it functions in RNA editing and plant development. Arabidopsis null mutants of grs1 exhibit slow growth and sterility...
October 2016: Journal of Experimental Botany
Wonjong Lee, Eun-Rhan Woo, Dong Gun Lee
Phytol, isolated from Aster yomena, is widely distributed as a constituent of chlorophyll. In the present study, we confirmed the antibacterial activity of phytol and its mechanism inducing oxidative cell death in Pseudomonas aeruginosa. In phytol-treated cells, elevated level of intracellular reactive oxygen species (ROS) and transient NADH depletion were observed. These results demonstrated that phytol induced ROS accumulation and that the electron transport chain was involved in increase of ROS. Due to this ROS generation, the imbalance developed between intracellular ROS and the antioxidant defense system, leading to decrease of reduced glutathione (GSH)...
September 25, 2016: Free Radical Research
Namrata Singh, Jana Hroudová, Zdeněk Fišar
Impairment of mitochondrial metabolism, particularly the electron transport chain (ETC), as well as increased oxidative stress might play a significant role in pathogenesis of Alzheimer's disease (AD). Some effects of drugs used for symptomatic AD treatment may be related to their direct action on mitochondrial function. In vitro effects of pharmacologically different cognitives (galantamine, donepezil, rivastigmine, 7-MEOTA, memantine) and nootropic drugs (latrepirdine, piracetam) were investigated on selected mitochondrial parameters: activities of ETC complexes I, II + III, and IV, citrate synthase, monoamine oxidase (MAO), oxygen consumption rate, and hydrogen peroxide production of pig brain mitochondria...
September 23, 2016: Molecular Neurobiology
Ariana Q Farrand, Rebecca A Gregory, Cristina M Bäckman, Kristi L Helke, Heather A Boger
Mitochondrial dysfunction has been implicated in the degeneration of dopamine (DA) neurons in Parkinson's disease (PD). In addition, animal models of PD utilizing neurotoxins, such as 6-hydroxydopamine and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, have shown that these toxins disrupt mitochondrial respiration by targeting complex I of the electron transport chain, thereby impairing DA neurons in these models. A MitoPark mouse model was created to mimic the mitochondrial dysfunction observed in the DA system of PD patients...
September 19, 2016: Brain Research
Hao Song, Xiaoji Fan, Guangfu Liu, Jiahui Xu, Xingxing Li, Yuzhu Tan, Haifeng Qian
The widely used solvent extractant, tributyl phosphate (TBP), primarily used as a solvent for the conventional processing of nuclear fuel, has come under scrutiny recently due to concerns surrounding potential environmental contamination and toxicity. In this study, we found that, in Phaeodactylum tricornutum, administration of TBP severely inhibited algal cell growth by reducing photosynthetic efficiency and inducing oxidative stress. We further explored the effect of TBP by examining the gene expression of the photosynthetic electron transport chain and its contribution to reactive oxygen species (ROS) burst...
September 16, 2016: Environmental Science and Pollution Research International
Marie H Foss, Sovitj Pou, Patrick M Davidson, Jennifer L Dunaj, Rolf W Winter, Sovijja Pou, Meredith H Licon, Julia K Doh, Yuexin Li, Jane X Kelly, Rozalia A Dodean, Dennis R Koop, Michael K Riscoe, Georgiana E Purdy
New treatments for tuberculosis infection are critical to combat the emergence of multidrug- and extensively drug-resistant Mycobacterium tuberculosis (Mtb). We report the characterization of a diphenylether-modified adamantyl 1,2-diamine that we refer to as TBL-140, which has a minimal inhibitory concentration (MIC99) of 1.2 μg/mL. TBL-140 is effective against drug-resistant Mtb and nonreplicating bacteria. In addition, TBL-140 eliminates expansion of Mtb in cell culture infection assays at its MIC. To define the mechanism of action of this compound, we performed a spontaneous mutant screen and biochemical assays...
July 8, 2016: ACS Infectious Diseases
Ignacio Amigo, Sergio Luiz Menezes-Filho, Luis Alberto Luévano-Martínez, Bruno Chausse, Alicia J Kowaltowski
Caloric restriction (CR) protects against many cerebral pathological conditions that are associated with excitotoxic damage and calcium overload, although the mechanisms are still poorly understood. Here we show that CR strongly protects against excitotoxic insults in vitro and in vivo in a manner associated with significant changes in mitochondrial function. CR increases electron transport chain activity, enhances antioxidant defenses, and favors mitochondrial calcium retention capacity in the brain. These changes are accompanied by a decrease in cyclophilin D activity and acetylation and an increase in Sirt3 expression...
September 13, 2016: Aging Cell
Sitakanta Satapathy, Edamana Prasad
Alteration of native gelation properties of anthracene and pyrene cored first generation poly(aryl ether) dendrons, G1-An and G1-Py, by introducing a common acceptor, 2,4,7-trinitro-9H-fluoren-9-one (TNF), results in forming charge transfer gels in long chain alcoholic solvents. This strategy leads to significant perturbation of optical and electronic properties within the gel matrix. Consequently, a noticeable increase of their electrical conductivities is observed, making these poly(aryl ether) dendron based gels potential candidates for organic electronics...
October 5, 2016: ACS Applied Materials & Interfaces
Amanda R Oran, Clare M Adams, Xiao-Yong Zhang, Victoria J Gennaro, Harla K Pfeiffer, Hestia S Mellert, Hans E Seidel, Kirsten Mascioli, Jordan Kaplan, Mahmoud R Gaballa, Chen Shen, Isidore Rigoutsos, Michael P King, Justin L Cotney, Jamie J Arnold, Suresh D Sharma, Ubaldo E Martinez-Outschoorn, Christopher R Vakoc, Lewis A Chodosh, James E Thompson, James E Bradner, Craig E Cameron, Gerald S Shadel, Christine M Eischen, Steven B McMahon
Despite ubiquitous activation in human cancer, essential downstream effector pathways of the MYC transcription factor have been difficult to define and target. Using a structure/function-based approach, we identified the mitochondrial RNA polymerase (POLRMT) locus as a critical downstream target of MYC. The multifunctional POLRMT enzyme controls mitochondrial gene expression, a process required both for mitochondrial function and mitochondrial biogenesis. We further demonstrate that inhibition of this newly defined MYC effector pathway causes robust and selective tumor cell apoptosis, via an acute, checkpoint-like mechanism linked to aberrant electron transport chain complex assembly and mitochondrial reactive oxygen species (ROS) production...
August 31, 2016: Oncotarget
Luana Naia, Tatiana R Rosenstock, Ana M Oliveira, Sofia I Oliveira-Sousa, Gladys L Caldeira, Catarina Carmo, Mário N Laço, Michael R Hayden, Catarina R Oliveira, A Cristina Rego
Sirtuin 1 (SIRT1) is a nicotinamide adenine dinucleotide (NAD(+))-dependent lysine deacetylase that regulates longevity and enhances mitochondrial metabolism. Both activation and inhibition of SIRT1 were previously shown to ameliorate neuropathological mechanisms in Huntington's disease (HD), a neurodegenerative disease that selectively affects the striatum and cortex and is commonly linked to mitochondrial dysfunction. Thus, in this study, we tested the influence of resveratrol (RESV, a SIRT1 activator) versus nicotinamide (NAM, a SIRT1 inhibitor) in counteracting mitochondrial dysfunction in HD models, namely striatal and cortical neurons isolated from YAC128 transgenic mice embryos, HD human lymphoblasts, and an in vivo HD model...
September 2, 2016: Molecular Neurobiology
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