How does succinate affect cellular respiration

In this communication, we propose that the removal of a metabolic block on M. Compounds that serve to reduce quinones in non-dividing organisms would exhibit the pleiotropic effects garnered by increasing respiration, including enhancing membrane potential-driven uptake and decreasing fitness.

Thus, progress toward the goal of shortening chemotherapy might be better served by searching for enhancers of respiration, which may reduce the numbers of organisms which are shifted to a persistent state. Attenuated strains of M. Null mutants in M. T-Coffee [62] was used to assess homology between enzyme subunits Figure 1 and scores are presented as alignments of individual subunits corresponding to sdh2.

For a full list of strains used in this work, see Table S1. For growth experiments using single carbon sources, 7H9 media was supplemented with NaCl and BSA and individual carbon sources see Supplementary Methods for more detail.

Column eluents were delivered via Electrospray Ionization. The flow rate is 0. The mass spectrometer was operated in V mode for high sensitivity using a capillary voltage of 2 kV and a cone voltage of 17 V. For further details, see Metabolomics in Text S1. Measurement of oxygen consumption rate in M. For culture densities below OD 4. To detect induction of oxygen consumption by reductants, 5 mL early stationary phase cells OD 5. We grew mycobacterial strains as described above in media containing OADC and the appropriate antibiotic for two passages before a single passage in media in which antibiotic was omitted immediately prior to animal infection.

Four mice from each infection group were killed 24 h post-exposure, and lung homogenates were plated on 7H9-agar plates to determine the efficiency of aerosolization. We determined bacterial loads in lungs and spleen by plating for CFU at the indicated times from four mice per infection group.

Five mice from each group were also used to determine survival times of infected mice. Mouse studies were performed in accordance to National Institutes of Health guidelines using recommendations in the Guide for the Care and Use of Laboratory Animals.

Deletion of sdh1 results in succinate accumulation in both virulent and attenuated M. Parental or mutant cultures were grown to OD 0.

Stable isotope labeling confirms Sdh1 to be an aerobic succinate dehydrogenase. Direction of carbon flux was determined by addition of 1,4 13 C 2 -aspartate to cells in mid logarithmic growth phase A or after 10 days of hypoxic adaptation B and extraction following a 24 hour labeling period see Metabolomics in Text S1. The diagram depicts the proportion of relevant isotopologues for each intermediate on a simplified TCA schematic.

Fold-change was calculated by determination of the labeled proportion of each isotopomer consisting of labeled intensities minus weighted average intensities to normalize for naturally occurring isotopes, then divided by the sum of labeled intensities.

Arrows within cells indicate increase, decrease, or no change in abundance for respective isotopologues of mean intensity from three biological replicates and are meant to be illustrative. Sdh mutants display decreased survival in hypoxia upon disruption of the proton gradient.

The results from a single representative experiment are shown here. Regulated expression is desirable for complementation of ETC gene deletions. Complementation of the respiratory phenotype of M. Parent and mutant strains were inoculated into a bioreactor at OD 0. DO was recorded as described in Methods. Growth of M. X-axis Inoculation time includes data only from the time during which oxygen is available first 8 days , absorbance is measured at intervals and values are interpolated for visualization.

Changes in midpoint redox potential of cultures operating in batch mode precede resumption of respiration. As oxygen is depleted, cells are seen to switch off respiration and DO builds up in the vessel. A change in redox midpoint potential red shaded can be seen before oxygen consumption resumes blue shaded and the process repeats twice more. Data is representative of two separate experiments.

Change in pH was observed in batch culture media over the course of aerobic growth for M. Mice were infected via low dose aerosol see Methods in Text S1 and burden was assessed over time by plating whole organ homogenates on 7H10 plates. Four mice per group were sacrificed at each timepoint. Mice were infected as described in Methods. Whole lungs were sectioned and alternate sections were acid fast and hematoxylin and eosin stained. The images above were chosen to be representative of each group.

The authors wish to thank Drs. Performed the experiments: TH. Abstract In chronic infection, Mycobacterium tuberculosis bacilli are thought to enter a metabolic program that provides sufficient energy for maintenance of the protonmotive force, but is insufficient to meet the demands of cellular growth.

Author Summary This work establishes the principle that Mycobacterium tuberculosis undergoes a metabolic remodeling as oxygen concentrations fall that serves to decrease its rate of oxygen consumption and therefore oxidative phosphorylation.

Introduction The World Health Organization has estimated the prevalence of Tuberculosis TB in the human population to be nearly two billion people. Download: PPT. Figure 1. Results M. Figure 2. Logarithmic growth is unaffected in sdh1 mutants, but cultures do not survive stationary phase. The putative operon Rvc-Rvc encodes a succinate dehydrogenase Succinate dehydrogenase catalyzes the two-electron oxidation of succinate to fumarate with a corresponding reduction of quinone to quinol, but physiologically, the succinate oxidation:fumarate reduction catalytic ratios are dependent on substrate concentrations and are critically dependent on the redox potential [17] , [18].

Figure 3. Loss of SDH1 uncouples respiration and growth As preservation of a proton motive force PMF is an important component of anaerobic survival, we monitored CFUs of sdh mutant strains in aerobic and anaerobic conditions in the presence of sub-lethal concentrations of the protononophore carbonyl cyanide m-chlorophenyl hydrazone CCCP.

Figure 4. ETC mutants display disrupted oxygen consumption which negatively affects growth rates. Table 1. Table 2. Membrane potential in mV of M. Meisel', M. Nauk SSSR, Kochetov, G.

Download references. Nauki 5, Pushchino, Moscow oblast, , Russia. Il'chenko, N. Shyshkanova, A. Sokolov, T. You can also search for this author in PubMed Google Scholar. Correspondence to A. Reprints and Permissions.

Il'chenko, A. Microbiology 74, — Download citation. Enzyme-catalyzed reactions are responsible for breaking down organic molecules usually carbohydrates or fats.

During these enzyme reactions, a small amount of energy is channeled into molecules of ATP. ATP is found in every living cell and can relocate energy wherever it is needed. See Figure 2 for the structure of ATP. Oxygen is used in cellular respiration. It is a diatomic molecule i. As it pulls electrons towards it, it releases energy from the chemical bonds. Potential energy from our food is combined with oxygen and creates products of carbon dioxide CO 2 and water H 2 O which releases energy to form the molecule ATP.

For example, the monosaccharide glucose , the most basic form of carbohydrate can be combined with oxygen. The high-energy electrons that are found in the glucose are transferred to the oxygen and potential energy is released. The energy is stored in the form of ATP. This final process of cellular respiration takes place on the inner membrane of the mitochondria. Instead of all the energy being released at once, the electrons go down the electron transport chain.

The energy is released in small pieces and that energy is used to form ATP. See below to understand more about the stages of cellular respiration including the electron transport chain. Forum Question: How many water molecules are produced by cellular respiration? Featured Answer! Cellular respiration can be written as chemical equations.

An example of the aerobic respiration equation is in Figure 3. Below are examples of aerobic respiration and anaerobic cellular respiration : lactic acid fermentation and alcoholic fermentation.

Most prokaryotes and eukaryotes use the process of aerobic respiration. As mentioned above, it is the process of cellular respiration in the presence of oxygen. Water and carbon dioxide are the end products of this reaction along with energy. See Figure 3.

In lactic acid fermentation, 6 carbon sugars, such as glucose are converted into energy in the form of ATP. However, during this process lactate is also released, which in solution becomes lactic acid. See figure 4 for an example of a lactic acid fermentation equation. It can occur in animal cells such as muscle cells as well as some prokaryotes.

In humans, the lactic acid build-up in muscles can occur during vigorous exercise when oxygen is not available. The aerobic respiration pathway is switched to the lactic acid fermentation pathway in the mitochondria which although produces ATP; it is not as efficient as aerobic respiration. The lactic acid build-up in muscles can also be painful. Alcoholic fermentation also known as ethanol fermentation is a process that converts sugars into ethyl alcohol and carbon dioxide. It is carried out by yeast and some bacteria.

Alcoholic fermentation is used by humans in the process of making alcoholic drinks such as wine and beer. During alcoholic fermentation, sugars are broken down to form pyruvate molecules in a process known as glycolysis.

Two molecules of pyruvic acid are generated during the glycolysis of a single glucose molecule. These pyruvic acid molecules are then reduced to two molecules of ethanol and two molecules of carbon dioxide.

The pyruvate can be transformed into ethanol under anaerobic conditions where it begins by converting into acetaldehyde, which releases carbon dioxide and acetaldehyde is converted into ethanol.

Figure 5 shows an alcoholic fermentation equation. Methanogenesis is a process only carried out by anaerobic bacteria. These bacteria belong to the phylum Euryarchaeota and they include Methanobacteriales, Methanococcales, Methanomicrobiales, Methanopyrales, and Methanosarcinales. Methanogens only occur in oxygen-depleted environments, such as sediments, aquatic environments, and in the intestinal tracts of mammals.

There are 3 pathways for methanogenesis:. This process involves activating acetate into acetyl-coenzyme A acetyl-CoA , from which a methyl group is then transferred into the central methanogenic pathway. Acetoclastic methanogens split acetate in the following way:. Acetoclastic methanogenesis is performed by Methanosarcina and Methanosarcinales and is most often found in freshwater sediments. Here, it is thought that acetate contributes to around two-thirds of the total methane formation on earth on an annual basis.

In methylotrophic methanogenesis, methanol or methylamines serve as the substrate instead of acetate. This process can be observed in marine sediments where methylated substrates can be found. Some acetoclastic methanosarcinales and at least one member of the Methanomicrobiales can also use this second pathway. Finally, hydrogenotrophic methanogenesis is a process that is used by Methanobacteriales, Methanococcales, Methanomicrobiales, Methanopyrales, and Methanosarcinales i. In this reaction, hydrogenotrophic methanogens use hydrogen for the reduction of carbon dioxide, carbon monoxide, or formate according to the following:.

Although methanogenesis is a type of respiration, an ordinary electron transport chain is not used. Methanogens instead rely on several coenzymes, including coenzyme F, which is involved in the activation of hydrogen, and coenzyme M, which is involved in the terminal reduction of CH3 groups to methane Figure 6.

What are the 4 stages of cellular respiration? There are 4 stages of the cellular respiration process. These are Glycolysis, the transition reaction, the Krebs cycle also known as the citric acid cycle , and the electron transport chain with chemiosmosis.

Glycolysis is a series of reactions that extract energy from glucose by splitting it into 2 molecules of pyruvate. Glycolysis is a biochemical pathway that evolved long ago and is found in the majority of organisms. In organisms that perform cellular respiration, glycolysis is the first stage of the process.

Before glycolysis begins, glucose must be transported into the cell and phosphorylated. In most organisms, this occurs in the cytosol. Hertz, L. Astrocytic glycogenolysis: mechanisms and functions. Metabolic brain disease 30 , —, doi: Hillered, L. Continuous monitoring of cerebral metabolism in traumatic brain injury: a focus on cerebral microdialysis. Current opinion in critical care 12 , —, doi: Gardner, R. Dementia risk after traumatic brain injury vs nonbrain trauma: the role of age and severity.

JAMA neurology 71 , —, doi: Traumatic brain injury in later life increases risk for Parkinson disease. Ann Neurol 77 , —, doi: Perry, D. Association of traumatic brain injury with subsequent neurological and psychiatric disease: a meta-analysis.

Journal of neurosurgery , —, doi: JNS Amaral, A. Glia 64 , 21—34, doi: Download references. Susan Giorgi-Coll, Peter J. Hutchinson, Mark R. You can also search for this author in PubMed Google Scholar. The study concept was by K. All authors reviewed and edited the manuscript.

Kotter or Keri L. Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Reprints and Permissions. Giorgi-Coll, S. Succinate supplementation improves metabolic performance of mixed glial cell cultures with mitochondrial dysfunction. Sci Rep 7, Download citation. Received : 26 January Accepted : 27 March Published : 21 April Anyone you share the following link with will be able to read this content:. Sorry, a shareable link is not currently available for this article.

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If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate. Advanced search. Skip to main content Thank you for visiting nature. Download PDF. Subjects Cellular neuroscience Glial biology. Abstract Mitochondrial dysfunction, the inability to efficiently utilise metabolic fuels and oxygen, contributes to pathological changes following traumatic spinal cord or traumatic brain injury TBI.

Introduction Following traumatic injury to the spinal cord or brain, a complex combination of pathological processes develop, in which cerebral energy perturbations and cellular metabolism play a key role 1 , 2 , 3 , 4 , 5. Results Characterisation of mixed glial cultures We first characterised our primary rat mixed glial cell culture model using immunocytochemistry.

Figure 1. Full size image. Figure 2. Figure 3. Figure 4. Discussion Mitochondrial dysfunction, where the brain is unable to utilise metabolic fuels and oxygen despite adequate provision, is thought to play a major role in the energy perturbations that occur following TBI.

Primary mixed glia cell cultures Primary mixed glia cultures were isolated from P0 to P2 neonatal Sprague-Dawley rat forebrains as previously described Mitochondrial dysfunction experiments Mitochondrial dysfunction was induced in mixed glial cultures using rotenone, an inhibitor of the complex I of the ETC. Metabolite Analysis Samples of culture medium were filtered using 0. Cell viability analysis Cell viability was assessed in live cells using the cell permeant dye Calcein-AM Life Technologies, Paisley, UK viable cells convert it to Calcein which emits green fluorescence and propidium iodide PI Life Technologies, Paisley, UK , which enters the nuclei of dead cells, making them fluoresce in red.

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