scholarly journals Formate as the Main Branch Point for Methylotrophic Metabolism in Methylobacterium extorquens AM1

2008 ◽  
Vol 190 (14) ◽  
pp. 5057-5062 ◽  
Author(s):  
Gregory J. Crowther ◽  
George Kosály ◽  
Mary E. Lidstrom
Keyword(s):  
Branch Point ◽  
Condensation Reaction ◽  
Carbon Assimilation ◽  
Methylobacterium Extorquens ◽  
Metabolic Fluxes ◽  
Carbon Compounds ◽  
Methylotrophic Growth ◽  
Methylene Tetrahydrofolate ◽  
Direct Condensation

ABSTRACT In serine cycle methylotrophs, methylene tetrahydrofolate (H4F) is the entry point of reduced one-carbon compounds into the serine cycle for carbon assimilation during methylotrophic metabolism. In these bacteria, two routes are possible for generating methylene H4F from formaldehyde during methylotrophic growth: one involving the reaction of formaldehyde with H4F to generate methylene H4F and the other involving conversion of formaldehyde to formate via methylene tetrahydromethanopterin-dependent enzymes and conversion of formate to methylene H4F via H4F-dependent enzymes. Evidence has suggested that the direct condensation reaction is the main source of methylene H4F during methylotrophic metabolism. However, mutants lacking enzymes that interconvert methylene H4F and formate are unable to grow on methanol, suggesting that this route for methylene H4F synthesis should have a significant role in biomass production during methylotrophic metabolism. This problem was investigated in Methylobacterium extorquens AM1. Evidence was obtained suggesting that the existing deuterium assay might overestimate the flux through the direct condensation reaction. To test this possibility, it was shown that only minor assimilation into biomass occurred in mutants lacking the methylene H4F synthesis pathway through formate. These results suggested that the methylene H4F synthesis pathway through formate dominates assimilatory flux. A revised kinetic model was used to validate this possibility, showing that physiologically plausible parameters in this model can account for the metabolic fluxes observed in vivo. These results all support the suggestion that formate, not formaldehyde, is the main branch point for methylotrophic metabolism in M. extorquens AM1.

scholarly journals Novel Formaldehyde-Activating Enzyme inMethylobacterium extorquens AM1 Required for Growth on Methanol

2000 ◽  
Vol 182 (23) ◽  
pp. 6645-6650 ◽  
Author(s):  
Julia A. Vorholt ◽  
Christopher J. Marx ◽  
Mary E. Lidstrom ◽  
Rudolf K. Thauer
Keyword(s):  
Biological Macromolecules ◽  
Methylotrophic Bacteria ◽  
Methylobacterium Extorquens ◽  
Metabolic Intermediate ◽  
Carbon Compounds ◽  
Methylotrophic Growth ◽  
Special Challenge ◽  
Encoding Gene

ABSTRACT Formaldehyde is toxic for all organisms from bacteria to humans due to its reactivity with biological macromolecules. Organisms that grow aerobically on single-carbon compounds such as methanol and methane face a special challenge in this regard because formaldehyde is a central metabolic intermediate during methylotrophic growth. In the α-proteobacterium Methylobacterium extorquens AM1, we found a previously unknown enzyme that efficiently catalyzes the removal of formaldehyde: it catalyzes the condensation of formaldehyde and tetrahydromethanopterin to methylene tetrahydromethanopterin, a reaction which also proceeds spontaneously, but at a lower rate than that of the enzyme-catalyzed reaction. Formaldehyde-activating enzyme (Fae) was purified from M. extorquens AM1 and found to be one of the major proteins in the cytoplasm. The encoding gene is located within a cluster of genes for enzymes involved in the further oxidation of methylene tetrahydromethanopterin to CO2. Mutants of M. extorquens AM1 defective in Fae were able to grow on succinate but not on methanol and were much more sensitive toward methanol and formaldehyde. Uncharacterized orthologs to this enzyme are predicted to be encoded by uncharacterized genes from archaea, indicating that this type of enzyme occurs outside the methylotrophic bacteria.

scholarly journals Assessment of Metabolic Fluxes in the Mouse Brain in Vivo Using 1H-[13C] NMR Spectroscopy at 14.1 Tesla

2015 ◽  
Vol 35 (5) ◽  
pp. 759-765 ◽  
Author(s):  
Lijing Xin ◽  
Bernard Lanz ◽  
gxia Lei ◽  
Rolf Gruetter
Keyword(s):  
Mouse Models ◽  
Mouse Brain ◽  
Conversion Rate ◽  
Tca Cycle ◽  
Compartment Model ◽  
13C Nmr Spectroscopy ◽  
Resonance Spectroscopy ◽  
Metabolic Fluxes ◽  
Short Echo Time

13C magnetic resonance spectroscopy (MRS) combined with the administration of 13C labeled substrates uniquely allows to measure metabolic fluxes in vivo in the brain of humans and rats. The extension to mouse models may provide exclusive prospect for the investigation of models of human diseases. In the present study, the short-echo-time (TE) full-sensitivity 1H-[13C] MRS sequence combined with high magnetic field (14.1 T) and infusion of [U-13C6] glucose was used to enhance the experimental sensitivity in vivo in the mouse brain and the 13C turnover curves of glutamate C4, glutamine C4, glutamate+glutamine C3, aspartate C2, lactate C3, alanine C3, γ-aminobutyric acid C2, C3 and C4 were obtained. A one-compartment model was used to fit 13C turnover curves and resulted in values of metabolic fluxes including the tricarboxylic acid (TCA) cycle flux VTCA (1.05 ± 0.04 μmol/g per minute), the exchange flux between 2-oxoglutarate and glutamate Vx (0.48 ± 0.02 μmol/g per minute), the glutamate-glutamine exchange rate Vgln (0.20 ± 0.02 μmol/g per minute), the pyruvate dilution factor Kdil (0.82 ± 0.01), and the ratio for the lactate conversion rate and the alanine conversion rate VLac/ VAla (10 ± 2). This study opens the prospect of studying transgenic mouse models of brain pathologies.

Effect of murine strain on metabolic pathways of glucose production after brief or prolonged fasting

2005 ◽  
Vol 289 (1) ◽  
pp. E53-E61 ◽  
Author(s):  
Shawn C. Burgess ◽  
F. Mark H. Jeffrey ◽  
Charles Storey ◽  
Angela Milde ◽  
Natasha Hausler ◽  
...  
Keyword(s):  
Genetic Manipulation ◽  
Glucose Production ◽  
Tca Cycle ◽  
Inbred Strains ◽  
Mouse Strains ◽  
Background Strain ◽  
Metabolic Fluxes ◽  
Inbred Strains Of Mice ◽  
Total Glucose

Background strain is known to influence the way a genetic manipulation affects mouse phenotypes. Despite data that demonstrate variations in the primary phenotype of basic inbred strains of mice, there is limited data available about specific metabolic fluxes in vivo that may be responsible for the differences in strain phenotypes. In this study, a simple stable isotope tracer/NMR spectroscopic protocol has been used to compare metabolic fluxes in ICR, FVB/N (FVB), C57BL/6J (B6), and 129S1/SvImJ (129) mouse strains. After a short-term fast in these mice, there were no detectable differences in the pathway fluxes that contribute to glucose synthesis. However, after a 24-h fast, B6 mice retain some residual glycogenolysis compared with other strains. FVB mice also had a 30% higher in vivo phospho enolpyruvate carboxykinase flux and total glucose production from the level of the TCA cycle compared with B6 and 129 strains, while total body glucose production in the 129 strain was ∼30% lower than in either FVB or B6 mice. These data indicate that there are inherent differences in several pathways involving glucose metabolism of inbred strains of mice that may contribute to a phenotype after genetic manipulation in these animals. The techniques used here are amenable to use as a secondary or tertiary tool for studying mouse models with disruptions of intermediary metabolism.

In vivo dynamics of galactose metabolism inSaccharomyces cerevisiae: Metabolic fluxes and metabolite levels

2001 ◽  
Vol 73 (5) ◽  
pp. 412-425 ◽  
Author(s):  
Simon Ostergaard ◽  
Lisbeth Olsson ◽  
Jens Nielsen
Keyword(s):  
Galactose Metabolism ◽  
Metabolic Fluxes

scholarly journals Coarse-grained modeling of mitochondrial metabolism enables subcellular flux inference from fluorescence lifetime imaging microscopy

2020 ◽  
Author(s):  
Xingbo Yang ◽  
Daniel J. Needleman
Keyword(s):  
Fluorescence Lifetime ◽  
Metabolic Flux ◽  
Living Cells ◽  
Coarse Grained ◽  
Fluorescence Lifetime Imaging Microscopy ◽  
Fluorescence Lifetime Imaging ◽  
Lifetime Imaging ◽  
Metabolic Fluxes ◽  
Subcellular Resolution

AbstractMitochondria are central to metabolism and their dysfunctions are associated with many diseases1–9. Metabolic flux, the rate of turnover of molecules through a metabolic pathway, is one of the most important quantities in metabolism, but it remains a challenge to measure spatiotemporal variations in mitochondrial metabolic fluxes in living cells. Fluorescence lifetime imaging microscopy (FLIM) of NADH is a label-free technique that is widely used to characterize the metabolic state of mitochondria in vivo10–18. However, the utility of this technique has been limited by the inability to relate FLIM measurement to the underlying metabolic activities in mitochondria. Here we show that, if properly interpreted, FLIM of NADH can be used to quantitatively measure the flux through a major mitochondrial metabolic pathway, the electron transport chain (ETC), in vivo with subcellular resolution. This result is based on the use of a coarse-grained NADH redox model, which we test in mouse oocytes subject to a wide variety of perturbations by comparing predicted fluxes to direct biochemical measurements and by self-consistency criterion. Using this method, we discovered a subcellular spatial gradient of mitochondrial metabolic flux in mouse oocytes. We showed that this subcellular variation in mitochondrial flux correlates with a corresponding subcellular variation in mitochondrial membrane potential. The developed model, and the resulting procedure for analyzing FLIM of NADH, are valid under nearly all circumstances of biological interest. Thus, this approach is a general procedure to measure metabolic fluxes dynamically in living cells, with subcellular resolution.

scholarly journals Genome of Methylobacillus flagellatus, Molecular Basis for Obligate Methylotrophy, and Polyphyletic Origin of Methylotrophy

2007 ◽  
Vol 189 (11) ◽  
pp. 4020-4027 ◽  
Author(s):  
Ludmila Chistoserdova ◽  
Alla Lapidus ◽  
Cliff Han ◽  
Lynne Goodwin ◽  
Liz Saunders ◽  
...  
Keyword(s):  
Formate Dehydrogenase ◽  
Tricarboxylic Acid Cycle ◽  
Methylococcus Capsulatus ◽  
Methylobacterium Extorquens ◽  
Circular Chromosome ◽  
Transport Chain ◽  
Carbon Compounds ◽  
Formaldehyde Oxidation ◽  
Global Carbon ◽  
Single Circular Chromosome

ABSTRACT Along with methane, methanol and methylated amines represent important biogenic atmospheric constituents; thus, not only methanotrophs but also nonmethanotrophic methylotrophs play a significant role in global carbon cycling. The complete genome of a model obligate methanol and methylamine utilizer, Methylobacillus flagellatus (strain KT) was sequenced. The genome is represented by a single circular chromosome of approximately 3 Mbp, potentially encoding a total of 2,766 proteins. Based on genome analysis as well as the results from previous genetic and mutational analyses, methylotrophy is enabled by methanol and methylamine dehydrogenases and their specific electron transport chain components, the tetrahydromethanopterin-linked formaldehyde oxidation pathway and the assimilatory and dissimilatory ribulose monophosphate cycles, and by a formate dehydrogenase. Some of the methylotrophy genes are present in more than one (identical or nonidentical) copy. The obligate dependence on single-carbon compounds appears to be due to the incomplete tricarboxylic acid cycle, as no genes potentially encoding alpha-ketoglutarate, malate, or succinate dehydrogenases are identifiable. The genome of M. flagellatus was compared in terms of methylotrophy functions to the previously sequenced genomes of three methylotrophs, Methylobacterium extorquens (an alphaproteobacterium, 7 Mbp), Methylibium petroleiphilum (a betaproteobacterium, 4 Mbp), and Methylococcus capsulatus (a gammaproteobacterium, 3.3 Mbp). Strikingly, metabolically and/or phylogenetically, the methylotrophy functions in M. flagellatus were more similar to those in M. capsulatus and M. extorquens than to the ones in the more closely related M. petroleiphilum species, providing the first genomic evidence for the polyphyletic origin of methylotrophy in Betaproteobacteria.

scholarly journals Skeletal muscle-endothelial cell cross talk through angiotensin II

2010 ◽  
Vol 299 (6) ◽  
pp. C1402-C1408 ◽  
Author(s):  
Leeann M. Bellamy ◽  
Adam P. W. Johnston ◽  
Michael De Lisio ◽  
Gianni Parise
Keyword(s):  
Skeletal Muscle ◽  
Endothelial Cells ◽  
Cell Migration ◽  
Endothelial Cell ◽  
Angiotensin Ii ◽  
Branch Point ◽  
Endothelial Cell Migration ◽  
Tube Length ◽  
Ang Ii

The role of angiotensin II (ANG II) in postnatal vasculogenesis and angiogenesis during skeletal muscle (SKM) regeneration is unknown. We examined the capacity of ANG II to stimulate capillary formation and growth during cardiotoxin-induced muscle regeneration in ACE inhibitor-treated ANG II type 1a receptor knockout (AT1a−/−) and C57Bl/6 control mice. Analysis of tibialis anterior (TA) cross-sections revealed 17% and 23% reductions in capillarization in AT1a−/− and captopril treated mice, respectively, when compared with controls, 21 days postinjury. Conversely, no differences in capillarization were detected at early time points (7 and 10 days). These results identify ANG II as a regulator of angiogenesis but not vasculogenesis in vivo. In vitro angiogenesis assays of human umbilical vein endothelial cells (HUVECs) further confirmed ANG II as proangiogeneic as 71% and 124% increases in tube length and branch point number were observed following ANG II treatment. Importantly, treatment of HUVECs with conditioned media from differentiated muscle cells resulted in an 84% and 203% increase in tube length and branch point number compared with controls, which was abolished following pretreatment of the cells with an angiotensin-converting enzyme inhibitor. The pro-angiogenic effect of ANG II can be attributed to an enhanced endothelial cell migration because both transwell and under agarose migration assays revealed a 37% and 101% increase in cell motility, respectively. Collectively, these data highlight ANG II as a proangiogenic regulator during SKM regeneration in vivo and more importantly demonstrates that ANG II released from SKM can signal endothelial cells and regulate angiogenesis through the induction of endothelial cell migration.

scholarly journals Synthesis, Anti-Inflammatory Activity, and In Silico Study of Novel Diclofenac and Isatin Conjugates

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Musab Mohamed Ibrahim ◽  
Tilal Elsaman ◽  
Mosab Yahya Al-Nour
Keyword(s):  
Virtual Screening ◽  
Condensation Reaction ◽  
Docking Study ◽  
Positive Control ◽  
Inflammatory Activity ◽  
Molecular Docking Study ◽  
Design Synthesis ◽  
Chemical Structures ◽  
Anti Inflammatory

The design, synthesis, and development of novel non-steroidal anti-inflammatory drugs (NSAIDs) with better activity and lower side effects are respectable area of research. Novel Diclofenac Schiff’s bases (M1, M2, M4, M7, and M8) were designed and synthesized, and their respective chemical structures were deduced using various spectral tools (IR, 1H NMR, 13C NMR, and MS). The compounds were synthesized via Schiff’s condensation reaction and their anti-inflammatory activity was investigated applying the Carrageenan-induced paw edema model against Diclofenac as positive control. Percentage inhibition of edema indicated that all compounds were exhibiting a comparable anti-inflammatory activity as Diclofenac. Moreover, the anti-inflammatory activity was supported via virtual screening using molecular docking study. Interestingly compound M2 showed the highest in vivo activity (61.32% inhibition) when compared to standard Diclofenac (51.36% inhibition) as well as the best binding energy score (-10.765) and the virtual screening docking score (-12.142).

A novel ratiometric AIE-based fluorescent probe for specific detection of Hcy/Cys and imaging of living cells in vivo

2021 ◽  
Author(s):  
Hong-Min Lv ◽  
Zi-Ke Jiang ◽  
Jing Wang ◽  
Tao Wang ◽  
Xiao-Nan Zhang ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Condensation Reaction ◽  
Living Cells ◽  
Specific Detection ◽  
Sensing Mechanism

The sensing mechanism toward Hcy/Cys is realized based on the condensation reaction, which breaks CN to form a thiazolidine adduct.

scholarly journals (E)-2-Cyano-3-(1H-Indol-3-yl)-N-Phenylacrylamide, a Hybrid Compound Derived from Indomethacin and Paracetamol: Design, Synthesis and Evaluation of the Anti-Inflammatory Potential

2020 ◽  
Vol 21 (7) ◽  
pp. 2591
Author(s):  
Pablo Silva ◽  
Maria de Almeida ◽  
Jamire Silva ◽  
Sonaly Albino ◽  
Renan Espírito-Santo ◽  
...  
Keyword(s):  
Condensation Reaction ◽  
Significant Inhibition ◽  
In Vitro Assays ◽  
Paw Edema ◽  
Substituted Anilines ◽  
Hybrid Compound ◽  
Design Synthesis ◽  
Anti Inflammatory

The compound (E)-2-cyano-3-(1H-indol-3-yl)-N-phenylacrylamide (ICMD-01) was designed and developed based on the structures of clinically relevant drugs indomethacin and paracetamol through the molecular hybridization strategy. This derivative was obtained by an amidation reaction between substituted anilines and ethyl 2-cyanoacetate followed by a Knoevenagel-type condensation reaction with indole aldehyde that resulted in both a viable synthesis and satisfactory yield. In order to assess the immunomodulatory and anti-inflammatory activity, in vitro assays were performed in J774 macrophages, and significant inhibitions (p < 0.05) of the production of nitrite and the production of cytokines (IL-1β and TNFα) in noncytotoxic concentrations were observed. The anti-inflammatory effect was also studied via CFA-induced paw edema in vivo tests and zymosan-induced peritonitis. In the paw edema assay, ICMD01 (50 mg kg−1) showed satisfactory activity, as did the group treated with dexamethasone, reducing edema in 2–6 h. In addition, there was no significant inhibition of PGE2, IL-1β or TNFα in vivo. Moreover, in the peritonitis assay that assesses leukocyte migration, ICMD-01 exhibited promising results. Therefore, these preliminary studies demonstrate this compound to be a strong candidate for an anti-inflammatory drug together with an improved gastrointestinal safety profile when compared to the conventional anti-inflammatory drugs.

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