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Oscar Gutierrez-Sanz, Enrico Forbrig, Ana P Batista, Manuela M Pereira, Johannes Salewski, Maria Andrea Mroginski, Robert Goetz, Antonio L De Lacey, Jacek Kozuch, Ingo Zebger
Respiratory Complex I (CpI) is a key player in the way organisms obtain energy, being an energy transducer, which couples NADH:quinone oxidoreduction with proton translocation by a mechanism that remains elusive so far. In this work, we monitored the function of CpI in a biomimetic supported lipid membrane (SLM) system assembled on a 4-aminothiophenol (4-ATP) self-assembled monolayer (SAM) by surface-enhanced infrared absorption spectroscopy (SEIRAS). 4-ATP serves not only as linker molecule to a nanostructured gold-surface but also as pH sensor, as indicated by concomitant density functional theory (DFT) calculations...
March 19, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Diana Fang, Eduardo N Maldonado
Cancer metabolism is emerging as a chemotherapeutic target. Enhanced glycolysis and suppression of mitochondrial metabolism characterize the Warburg phenotype in cancer cells. The flux of respiratory substrates, ADP, and Pi into mitochondria and the release of mitochondrial ATP to the cytosol occur through voltage-dependent anion channels (VDACs) located in the mitochondrial outer membrane. Catabolism of respiratory substrates in the Krebs cycle generates NADH and FADH2 that enter the electron transport chain (ETC) to generate a proton motive force that maintains mitochondrial membrane potential (ΔΨ) and is utilized to generate ATP...
2018: Advances in Cancer Research
Gosse Overal, Bas Teusink, Frank J Bruggeman, Josephus Hulshof, Robert Planqué
Yeast glycolysis has been the focus of research for decades, yet a number of dynamical aspects of yeast glycolysis remain poorly understood at present. If nutrients are scarce, yeast will provide its catabolic and energetic needs with other pathways, but the enzymes catalysing upper glycolytic fluxes are still expressed. We conjecture that this overexpression facilitates the rapid transition to glycolysis in case of a sudden increase in nutrient concentration. However, if starved yeast is presented with abundant glucose, it can enter into an imbalanced state where glycolytic intermediates keep accumulating, leading to arrested growth and cell death...
March 14, 2018: Mathematical Biosciences
Nanako Kanno, Katsumi Matsuura, Shin Haruta
Purple photosynthetic bacteria utilize light energy for growth. We previously demonstrated that light energy contributed to prolonging the survival of multiple purple bacteria under carbon-starved conditions. In order to clarify the effects of illumination on metabolic states under carbon-starved, non-growing conditions, we herein compared the metabolic profiles of starved cells in the light and dark using the purple bacterium, Rhodopseudomonas palustris. The metabolic profiles of starved cells in the light were markedly different from those in the dark...
March 13, 2018: Microbes and Environments
Silvia Ravera, Maria Grazia Signorello, Martina Bartolucci, Sara Ferrando, Lucia Manni, Federico Caicci, Daniela Calzia, Isabella Panfoli, Alessandro Morelli, Giuliana Leoncini
BACKGROUND INFORMATION: Energy demand in human platelets is very high, to carry out their functions. As for most human cells, the aerobic metabolism represents the primary energy source in platelets, even though mitochondria are negligibly represented. Following the hypothesis that other structures could be involved in chemical energy production, in this work, we have investigated the functional expression of an extramitochondrial aerobic metabolism in platelets. RESULTS: Oximetric and luminometric analyses showed that platelets consume large amounts of oxygen and produce ATP in the presence of common respiring substrates, such as pyruvate + malate or succinate, although morphological electron microscopy analysis showed that these contain few mitochondria...
March 14, 2018: Biology of the Cell
Taofeek O Ajiboye, Evelyn Skiebe, Gottfried Wilharm
Phenolic acids with catechol groups are good prooxidants because of their low redox potential. In this study, we provided data showing that phenolic acids, caffeic acid, gallic acid and protocatechuic acid, enhanced colistin-mediated bacterial death by inducing redox imbalance. The minimum inhibitory concentrations of these phenolic acids against Acinetobacter baumannii AB5075 were considerably lowered for ΔsodB and ΔkatG mutants. Checkerboard assay shows synergistic interactions between colistin and phenolic acids...
March 7, 2018: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
Dinakaran Murugesan, Peter C Ray, Tracy Bayliss, Gareth A Prosser, Justin R Harrison, Kirsteen Green, Candice Soares de Melo, Tzu-Shean Feng, Leslie J Street, Kelly Chibale, Digby F Warner, Valerie Mizrahi, Ola Epemolu, Paul Scullion, Lucy Ellis, Jennifer Riley, Yoko Shishikura, Liam Ferguson, Maria Osuna-Cabello, Kevin D Read, Simon R Green, Dirk A Lamprecht, Peter M Finin, Adrie J C Steyn, Thomas R Ioerger, Jim Sacchettini, Kyu Y Rhee, Kriti Arora, Clifton E Barry Iii, Paul G Wyatt, Helena Ingrid M Boshoff
Mycobacterium tuberculosis (MTb) possesses two non-proton pumping type II NADH dehydrogenase (NDH-2) enzymes which are predicted to be jointly essential for respiratory metabolism.. Furthermore, the structure of a closely related bacterial NDH-2 has been reported recently, allowing for the structure-based design of small-molecule inhibitors. Herein, we disclose MTb whole-cell structure-activity relationships (SAR) for a series of 2-mercapto-quinazolinones which target the ndh encoded NDH-2 with nanomolar potencies...
March 9, 2018: ACS Infectious Diseases
Taewoong Ha, Mi Kyoung Kim, Kwang-Su Park, Woong Jung, Hyunah Choo, Youhoon Chong
(-)-Epigallocatechin-3-gallate (EGCG) is known as a mitochondria-targeted molecule that can prevent mitochondrial deterioration and induce mitochondrial biogenesis by modulating key regulators of mitochondrial metabolism. In this study, we tackled whether derivatization of EGCG could result in enhancement of its effects on mitochondrial biogenesis. EGCG, EGCG peracetate (AcEGCG), and its 4″- O-alkyl substituted congeners prepared by previously reported procedures were biologically evaluated. Interestingly, EGCG and AcEGCG were only marginally effective in inducing mitochondrial biogenesis, while AcEGCG congeners with an alkyl group at the 4″- O position showed significantly increased biological activity compared to their parent compound...
March 8, 2018: Journal of Agricultural and Food Chemistry
Yukai Suo, Hongxin Fu, Mengmeng Ren, Zhengping Liao, Yi Ma, Jufang Wang
No abstract text is available yet for this article.
March 6, 2018: Journal of Biotechnology
Tania Pereira, Ester Vilaprinyo, Gemma Belli, Enric Herrero, Baldiri Salvado, Albert Sorribas, Gisela Altés, Rui Alves
Microorganisms evolved adaptive responses to survive stressful challenges in ever-changing environments. Understanding the relationships between the physiological/metabolic adjustments allowing cellular stress adaptation and gene expression changes being used by organisms to achieve such adjustments may significantly impact our ability to understand and/or guide evolution. Here, we studied those relationships during adaptation to various stress challenges in Saccharomyces cerevisiae, focusing on heat stress responses...
February 27, 2018: Cell Reports
Annette R Rowe, Pournami Rajeev, Abhiney Jain, Sahand Pirbadian, Akihiro Okamoto, Jeffrey A Gralnick, Mohamed Y El-Naggar, Kenneth H Nealson
While typically investigated as a microorganism capable of extracellular electron transfer to minerals or anodes, Shewanella oneidensis MR-1 can also facilitate electron flow from a cathode to terminal electron acceptors, such as fumarate or oxygen, thereby providing a model system for a process that has significant environmental and technological implications. This work demonstrates that cathodic electrons enter the electron transport chain of S. oneidensis when oxygen is used as the terminal electron acceptor...
February 27, 2018: MBio
Saroj Poudel, Daniel R Colman, Kathryn R Fixen, Rhesa N Ledbetter, Yanning Zheng, Natasha Pence, Lance C Seefeldt, John W Peters, Caroline S Harwood, Eric S Boyd
Nitrogenase catalyzes the reduction of dinitrogen (N2 ) using low potential electrons from ferredoxin (Fd) or flavodoxin (Fld) through an ATP dependent process. Since its emergence in an anaerobic chemoautotroph, this oxygen (O2 ) sensitive enzyme complex has evolved to operate in a variety of genomic and metabolic backgrounds including those of aerobes, anaerobes, chemotrophs, and phototrophs. However, whether pathways of electron delivery to nitrogenase are influenced by these different metabolic backgrounds is not well understood...
February 26, 2018: Journal of Bacteriology
Iram Khan Iqbal, Sapna Bajeli, Ajit Kumar Akela, Ashwani Kumar
Mycobacterium tuberculosis (Mtb) exhibits remarkable metabolic flexibility that enables it to survive a plethora of host environments during its life cycle. With the advent of bedaquiline for treatment of multidrug-resistant tuberculosis, oxidative phosphorylation has been validated as an important target and a vulnerable component of mycobacterial metabolism. Exploiting the dependence of Mtb on oxidative phosphorylation for energy production, several components of this pathway have been targeted for the development of new antimycobacterial agents...
February 23, 2018: Pathogens
Shanshan Zhang, Shuang Liu, Nan Wu, Youhua Yuan, Wenhong Zhang, Ying Zhang
As dormant phenotypic variants of bacteria, persisters account for many chronic infections affecting human health. Despite numerous studies, the role of small non-coding RNA (sRNA) in bacterial persistence has not been reported. To investigate the role of Hfq-interacting sRNA in persistence, we constructed the deletion mutants of 20 Hfq-interacting sRNAs (RyhB, GcvB, MgrR, RybB, MicF, SgrS, RprA, DicF, SsrS, FnrS, GadY, DsrA, OmrB, ArcZ, RyeB, RydC, OmrA, MicA, MicC, and ChiX) to assess their persistence capacity in uropathogenic Escherichia coli strain UTI89 and identified a new sRNA RyhB being involved in persister formation...
2018: Frontiers in Microbiology
Joana S Sousa, Edoardo D'Imprima, Janet Vonck
Mitochondria are the power stations of the eukaryotic cell, using the energy released by the oxidation of glucose and other sugars to produce ATP. Electrons are transferred from NADH, produced in the citric acid cycle in the mitochondrial matrix, to oxygen by a series of large protein complexes in the inner mitochondrial membrane, which create a transmembrane electrochemical gradient by pumping protons across the membrane. The flow of protons back into the matrix via a proton channel in the ATP synthase leads to conformational changes in the nucleotide binding pockets and the formation of ATP...
2018: Sub-cellular Biochemistry
Qian Lu, Yue Zhao, Xintong Gao, Junqiu Wu, Haixuan Zhou, Pengfei Tang, Qingbin Wei, Zimin Wei
Composting is an environment friendly method to recycling organic waste. However, with the increasing concern about greenhouse gases generated in global atmosphere, it is significant to reduce the emission of carbon dioxide (CO2). This study analyzes tricarboxylic acid (TCA) cycle regulators on the effect of reducing CO2 emission, and the relationship among organic component (OC) degradation and transformation and microorganism during composting. The results showed that adding adenosine tri-phosphate (ATP) and nicotinamide adenine dinucleotide (NADH) could enhance the transformation of OC and increase the diversity of microorganism community...
February 2, 2018: Bioresource Technology
Michelle Le, Fiona E McNeill, Colin B Seymour, Andrej Rusin, Kevin Diamond, Andrew J Rainbow, James Murphy, Carmel E Mothersill
Radiation-induced biophotons are an electromagnetic form of bystander signalling. In human cells, biophoton signalling is capable of eliciting effects in non-irradiated bystander cells. However, the mechanisms by which the biophotons interact and act upon the bystander cells are not clearly understood. Mitochondrial energy production and ROS are known to be involved but the precise interactions are not known. To address this question, we have investigated the effect of biophoton emission upon the function of the complexes of oxidative phosphorylation (OXPHOS)...
February 7, 2018: Environmental Research
Chunyu Liu, Jessica L Fetterman, Poching Liu, Yan Luo, Martin G Larson, Ramachandran S Vasan, Jun Zhu, Daniel Levy
Increasing evidence implicates mitochondrial dysfunction in aging and age-related conditions. But little is known about the molecular basis for this connection. A possible cause may be mutations in the mitochondrial DNA (mtDNA), which are often heteroplasmic-the joint presence of different alleles at a single locus in the same individual. However, the involvement of mtDNA heteroplasmy in aging and age-related conditions has not been investigated thoroughly. We deep-sequenced the complete mtDNA genomes of 356 Framingham Heart Study participants (52% women, mean age 43, mean coverage 4570-fold), identified 2880 unique mutations and comprehensively annotated them by MITOMAP and PolyPhen-2...
February 8, 2018: Human Genetics
Hai Wang, Zan Gao, Xuanyou Liu, Pranay Agarwal, Shuting Zhao, Daniel W Conroy, Guang Ji, Jianhua Yu, Christopher P Jaroniec, Zhenguo Liu, Xiongbin Lu, Xiaodong Li, Xiaoming He
Multidrug resistance is a major challenge to cancer chemotherapy. The multidrug resistance phenotype is associated with the overexpression of the adenosine triphosphate (ATP)-driven transmembrane efflux pumps in cancer cells. Here, we report a lipid membrane-coated silica-carbon (LSC) hybrid nanoparticle that targets mitochondria through pyruvate, to specifically produce reactive oxygen species (ROS) in mitochondria under near-infrared (NIR) laser irradiation. The ROS can oxidize the NADH into NAD+ to reduce the amount of ATP available for the efflux pumps...
February 8, 2018: Nature Communications
Sen Zhang, Ping Song, Shuang Li
The effect of the intracellular microenvironment in the presence of an oxygen vector during expression of a fusion protein in Escherichia coli was studied. Three organic solutions at different concentration were chosen as oxygen vectors for fumarase expression. The addition of n-dodecane did not induce a significant change in the expression of fumarase, while the activity of fumarase increased significantly to 124% at 2.5% n-dodecane added after 9h induction. The concentration of ATP increased sharply during the first 6h of induction, to a value 7600% higher than that in the absence of an oxygen-vector...
February 2, 2018: Brazilian Journal of Microbiology: [publication of the Brazilian Society for Microbiology]
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