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metabolic flux analysis

Jacqueline E Gonzalez, Maciek R Antoniewicz
Engineered microbes offer a practical and sustainable alternative to traditional industrial approaches. To increase the economic feasibility of biological processes, microbial isolates are engineered to take up inexpensive feedstocks (including lignocellulosic biomass, syngas, methane, and carbon dioxide), and convert them into substrates of central metabolism and further into value-added products. To trace the metabolism of these feedstocks into products, isotopic tracers are applied together with isotopomer analysis techniques such as (13)C-metabolic flux analysis to provide a detailed picture of pathway utilization...
October 22, 2016: Current Opinion in Biotechnology
Menghan Liu, Lake-Ee Quek, Ghazal Sultani, Nigel Turner
BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a common malignancy with dismal prognosis. Metastatic spread and therapeutic resistance, the main causes of PDAC-related mortalities, are both partially underlined by the epithelial-mesenchymal transition (EMT) of PDAC cells. While the role of Warburg metabolism has been recognized in supporting rapid cellular growth and proliferation in many cancer types, less is known about the metabolic changes occurring during EMT, particularly in the context of PDAC...
2016: Cancer & Metabolism
Akos A Gerencser, Shona A Mookerjee, Martin Jastroch, Martin D Brand
Analysis of the cellular mechanisms of metabolic disorders, including type 2 diabetes mellitus, is complicated by the large number of reactions and interactions in metabolic networks. Metabolic control analysis with appropriate modularization is a powerful method for simplifying and analyzing these networks. To analyze control of cellular energy metabolism in adherent cell cultures of the INS-1832/13 pancreatic β-cell model we adapted our microscopy assay of absolute mitochondrial membrane potential (ΔψM) to a fluorescence microplate reader format, and applied it in conjunction with cell respirometry...
October 20, 2016: Biochimica et Biophysica Acta
Andrew J Loder, Yejun Han, Aaron B Hawkins, Hong Lian, Gina L Lipscomb, Gerrit J Schut, Matthew W Keller, Michael W W Adams, Robert M Kelly
The 3-hydroxypropionate/4-hydroxybutyrate (3HP/4HB) cycle fixes CO2 in extremely thermoacidophilic archaea and holds promise for metabolic engineering because of its thermostability and potentially rapid pathway kinetics. A reaction kinetics model was developed to examine the biological and biotechnological attributes of the 3HP/4HB cycle as it operates in Metallosphaera sedula, based on previous information as well as on kinetic parameters determined here for recombinant versions of five of the cycle enzymes (malonyl-CoA/succinyl-CoA reductase, 3-hydroxypropionyl-CoA synthetase, 3-hydroxypropionyl-CoA dehydratase, acryloyl-CoA reductase, and succinic semialdehyde reductase)...
October 19, 2016: Metabolic Engineering
M J de Veth, V M Artegoitia, S R Campagna, H Lapierre, F Harte, C L Girard
The metabolites of choline have a central role in many mammalian biological processes, and choline supplementation to the periparturient dairy cow improves hepatic lipid metabolism. However, variability in responses to choline supplementation has highlighted a lack of understanding of choline absorption in the lactating dairy cow. Our objective was to determine net choline absorption by measuring net portal fluxes of choline and choline metabolites in cows receiving either dietary supplements of rumen-protected choline (RPC) or abomasal delivery of choline (ADC)...
October 19, 2016: Journal of Dairy Science
Sayed-Rzgar Hosseini, Andreas Wagner
BACKGROUND: Biological systems are rife with examples of pre-adaptations or exaptations. They range from the molecular scale - lens crystallins, which originated from metabolic enzymes - to the macroscopic scale, such as feathers used in flying, which originally served thermal insulation or waterproofing. An important class of exaptations are novel and useful traits with non-adaptive origins. Whether such origins could be frequent cannot be answered with individual examples, because it is a question about a biological system's potential for exaptation...
October 21, 2016: BMC Systems Biology
Bhavisha Bakrania, Joey P Granger, Romain Harmancey
The mammalian heart is a major consumer of ATP and requires a constant supply of energy substrates for contraction. Not surprisingly, alterations of myocardial metabolism have been linked to the development of contractile dysfunction and heart failure. Therefore, unraveling the link between metabolism and contraction should shed light on some of the mechanisms governing cardiac adaptation or maladaptation in disease states. The isolated working rat heart preparation can be used to follow, simultaneously and in real time, cardiac contractile function and flux of energy providing substrates into oxidative metabolic pathways...
September 28, 2016: Journal of Visualized Experiments: JoVE
Teresa Delgado-Goni, Maria Falck Miniotis, Slawomir Wantuch, Harold G Parkes, Richard Marais, Paul Workman, Martin O Leach, Mounia Beloueche-Babari
Understanding the impact of BRAF signaling inhibition in human melanoma on key disease mechanisms is important for developing biomarkers of therapeutic response and combination strategies to improve long term disease control. This work investigates the downstream metabolic consequences of BRAF inhibition with vemurafenib, the molecular and biochemical processes that underpin them, their significance for antineoplastic activity and potential as non-invasive imaging response biomarkers.(1)H NMR spectroscopy showed that vemurafenib decreases the glycolytic activity of BRAF mutant (WM266...
October 7, 2016: Molecular Cancer Therapeutics
Amit Ghosh, David Ando, Jennifer Gin, Weerawat Runguphan, Charles Denby, George Wang, Edward E K Baidoo, Chris Shymansky, Jay D Keasling, Héctor García Martín
Efficient redirection of microbial metabolism into the abundant production of desired bioproducts remains non-trivial. Here, we used flux-based modeling approaches to improve yields of fatty acids in Saccharomyces cerevisiae. We combined (13)C labeling data with comprehensive genome-scale models to shed light onto microbial metabolism and improve metabolic engineering efforts. We concentrated on studying the balance of acetyl-CoA, a precursor metabolite for the biosynthesis of fatty acids. A genome-wide acetyl-CoA balance study showed ATP citrate lyase from Yarrowia lipolytica as a robust source of cytoplasmic acetyl-CoA and malate synthase as a desirable target for downregulation in terms of acetyl-CoA consumption...
2016: Frontiers in Bioengineering and Biotechnology
Jeong Wook Lee, Jongho Yi, Tae Yong Kim, Sol Choi, Jung Ho Ahn, Hyohak Song, Moon-Hee Lee, Sang Yup Lee
Succinic acid (SA) is a four carbon dicarboxylic acid of great industrial interest that can be produced by microbial fermentation. Here we report development of a high-yield homo-SA producing Mannheimia succiniciproducens strain by metabolic engineering. The PALFK strain (ldhA(-), pta(-), ackA(-), fruA(-)) was developed based on optimization of carbon flux towards SA production while minimizing byproducts formation through the integrated application of in silico genome-scale metabolic flux analysis, omics analyses, and reconstruction of central carbon metabolism...
October 13, 2016: Metabolic Engineering
Perrin H Beatty, Matthias S Klein, Jeffrey J Fischer, Ian A Lewis, Douglas G Muench, Allen G Good
A comprehensive understanding of plant metabolism could provide a direct mechanism for improving nitrogen use efficiency (NUE) in crops. One of the major barriers to achieving this outcome is our poor understanding of the complex metabolic networks, physiological factors, and signaling mechanisms that affect NUE in agricultural settings. However, an exciting collection of computational and experimental approaches has begun to elucidate whole-plant nitrogen usage and provides an avenue for connecting nitrogen-related phenotypes to genes...
October 10, 2016: Plants (Basel, Switzerland)
Rémi Peyraud, Ludovic Cottret, Lucas Marmiesse, Jérôme Gouzy, Stéphane Genin
Bacterial pathogenicity relies on a proficient metabolism and there is increasing evidence that metabolic adaptation to exploit host resources is a key property of infectious organisms. In many cases, colonization by the pathogen also implies an intensive multiplication and the necessity to produce a large array of virulence factors, which may represent a significant cost for the pathogen. We describe here the existence of a resource allocation trade-off mechanism in the plant pathogen R. solanacearum. We generated a genome-scale reconstruction of the metabolic network of R...
October 2016: PLoS Pathogens
Vishal Kumar, Mehak Baweja, Puneet K Singh, Pratyoosh Shukla
Microorganisms play a crucial role in the sustainability of the various ecosystems. The characterization of various interactions between microorganisms and other biotic factors is a necessary footstep to understand the association and functions of microbial communities. Among the different microbial interactions in an ecosystem, plant-microbe interaction plays an important role to balance the ecosystem. The present review explores plant-microbe interactions using gene editing and system biology tools toward the comprehension in improvement of plant traits...
2016: Frontiers in Plant Science
Gahl Levy, Naomi Habib, Maria Angela Guzzardi, Daniel Kitsberg, David Bomze, Elishai Ezra, Basak E Uygun, Korkut Uygun, Martin Trippler, Joerg F Schlaak, Oren Shibolet, Ella H Sklan, Merav Cohen, Joerg Timm, Nir Friedman, Yaakov Nahmias
Viruses lack the basic machinery needed to replicate and therefore must hijack the host's metabolism to propagate. Virus-induced metabolic changes have yet to be systematically studied in the context of host transcriptional regulation, and such studies shoul offer insight into host-pathogen metabolic interplay. In this work we identified hepatitis C virus (HCV)-responsive regulators by coupling system-wide metabolic-flux analysis with targeted perturbation of nuclear receptors in primary human hepatocytes. We found HCV-induced upregulation of glycolysis, ketogenesis and drug metabolism, with glycolysis controlled by activation of HNF4α, ketogenesis by PPARα and FXR, and drug metabolism by PXR...
October 10, 2016: Nature Chemical Biology
Jin Chen, Michael A Henson
Synthesis gas fermentation is one of the most promising routes to convert synthesis gas (syngas; mainly comprised of H2 and CO) to renewable liquid fuels and chemicals by specialized bacteria. The most commonly studied syngas fermenting bacterium is Clostridium ljungdahlii, which produces acetate and ethanol as its primary metabolic byproducts. Engineering of C. ljungdahlii metabolism to overproduce ethanol, enhance the synthesize of the native byproducts lactate and 2,3-butanediol, and introduce the synthesis of non-native products such as butanol and butyrate has substantial commercial value...
October 5, 2016: Metabolic Engineering
Tomoyo Sakata-Kato, Dyann F Wirth
Given that resistance to all drugs in clinical use has arisen, discovery of new anti-malarial drug targets is eagerly anticipated. The Plasmodium mitochondrion has been considered a promising drug target largely based on its significant divergence from the host organelle as well as its involvement in ATP production and pyrimidine biosynthesis. However, the functions of Plasmodium mitochondrial protein complexes and associated metabolic pathways are not fully characterized. Here, we report the development of novel and robust bioenergetic assay protocols for Plasmodium falciparum asexual parasites utilizing a Seahorse Bioscience XFe24 Extracellular Flux Analyzer...
October 9, 2016: ACS Infectious Diseases
Daniel Machado, Markus J Herrgård, Isabel Rocha
Genome-scale metabolic reconstructions are currently available for hundreds of organisms. Constraint-based modeling enables the analysis of the phenotypic landscape of these organisms, predicting the response to genetic and environmental perturbations. However, since constraint-based models can only describe the metabolic phenotype at the reaction level, understanding the mechanistic link between genotype and phenotype is still hampered by the complexity of gene-protein-reaction associations. We implement a model transformation that enables constraint-based methods to be applied at the gene level by explicitly accounting for the individual fluxes of enzymes (and subunits) encoded by each gene...
October 2016: PLoS Computational Biology
C E Geisler, C Hepler, M R Higgins, B J Renquist
BACKGROUND: The increased incidence of obesity and associated metabolic diseases has driven research focused on genetically or pharmacologically alleviating metabolic dysfunction. These studies employ a range of fasting-refeeding models including 4-24 h fasts, "overnight" fasts, or meal feeding. Still, we lack literature that describes the physiologically relevant adaptations that accompany changes in the duration of fasting and re-feeding. Since the liver is central to whole body metabolic homeostasis, we investigated the timing of the fast-induced shift toward glycogenolysis, gluconeogenesis, and ketogenesis and the meal-induced switch toward glycogenesis and away from ketogenesis...
2016: Nutrition & Metabolism
Anubhav Srivastava, Greg M Kowalski, Damien L Callahan, Peter J Meikle, Darren J Creek
This is a perspective from the peer session on stable isotope labelling and fluxomics at the Australian & New Zealand Metabolomics Conference (ANZMET) held from 30 March to 1 April 2016 at La Trobe University, Melbourne, Australia. This report summarizes the key points raised in the peer session which focused on the advantages of using stable isotopes in modern metabolomics and the challenges in conducting flux analyses. The session highlighted the utility of stable isotope labelling in generating reference standards for metabolite identification, absolute quantification, and in the measurement of the dynamic activity of metabolic pathways...
October 1, 2016: Metabolites
Muhammad Tariq Saeed, Jamil Ahmad, Shahzina Kanwal, Andreana N Holowatyj, Iftikhar A Sheikh, Rehan Zafar Paracha, Aamir Shafi, Amnah Siddiqa, Zurah Bibi, Mukaram Khan, Amjad Ali
The alteration of glucose metabolism, through increased uptake of glucose and glutamine addiction, is essential to cancer cell growth and invasion. Increased flux of glucose through the Hexosamine Biosynthetic Pathway (HBP) drives increased cellular O-GlcNAcylation (hyper-O-GlcNAcylation) and contributes to cancer progression by regulating key oncogenes. However, the association between hyper-O-GlcNAcylation and activation of these oncogenes remains poorly characterized. Here, we implement a qualitative modeling framework to analyze the role of the Biological Regulatory Network in HBP activation and its potential effects on key oncogenes...
2016: PeerJ
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