187 peaks were acquired using GC-MS, of them 58 metabolites were identified (Fig 1). A list of mean values and standard deviations for all identified metabolites is provided in S3 Table. Based on the full metabolic data set, two principal components were identified by PCA analy- sis, all samples of RA patients were evidently separated from normal group by OPLS-DA analy- sis (Fig 1B) with high R 2 Y value (0.965) and Q 2 Y value (0.895). The concentrations of 13 metabolites were significantly different between RA patients and normal subjects by VIP 1 and p < 0.05 (Table 1). Of the13 metabolites, 7 metabolites were related to energymetabolism, including lactic acid, valine, citric acid, gluconic lactone, glucose, glucose-1-phosphate and mannose. Of them, valine was a branched-chain acid, citric acid was from TCA cycle, and other 5 metabolites were from carbohydrate metabolism. The concentration of lactic acid was increased and that of other 6 metabolites were decreased in synovial fluid of RA patients.
The current literature provides ample information regarding metabolic events during larval and adult phases of several arthropods (BRIEGEL et al., 2003; GOLDSTROHM et al., 2003; ZHOU et al., 2004a,b; BROWN et al., 2008). Nevertheless, aspects concerning energymetabolism such as the activity of central metabolic pathways in arthropod embryogenesis or the determination of energy reserves to be used are scarce. In the fruit fly Drosophila melanogaster an increase in glycogen content strongly correlated with protein levels in follicles and young embryos has been described (SHIOMI & KITAZUME, 1956; MEDINA & VALLEJO, 1989; GUTZEIT et al., 1993). Histochemical studies reveal that glycogen is the predominant form of carbohydrate storage in D. melanogaster eggs (YAMAZAKI & YANAGAWA, 2003). Furthermore, changes in protein content occur in an opposite direction to that determined for the carbohydrate content (GUTZEIT et al., 1993).
Metformin inhibits ATP production in mitochondria and this may be involved in the anti-hyperglycemic effects of the drug. Sirtuin 3 (SIRT3) is a mitochondrial protein deacetylase that regulates the function of the electron transport chain and maintains basal ATP yield. We hypothesized that metformin treatment could diminish mitochondrial ATP production through downregulation of SIRT3 expression. Glucagon and cAMP induced SIRT3 mRNA in mouse primary hepatocytes. Metformin prevented SIRT3 induction by glucagon. Moreover, metformin downregulated constitutive expression of SIRT3 in primary hepatocytes and in the liver in vivo. Estrogen related receptor alpha (ERRa) mediates regulation of Sirt3 gene by peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1a). ERRa mRNA expression was regulated in a similar manner as SIRT3 mRNA by glucagon, cAMP and metformin. However, a higher metformin concentration was required for downregulation of ERRa than SIRT3. ERRa siRNA attenuated PGC-1a mediated induction of SIRT3, but did not affect constitutive expression. Overexpression of the constitutively active form of AMP-activated protein kinase (AMPK) induced SIRT3 mRNA, indicating that the SIRT3 downregulation by metformin is not mediated by AMPK. Metformin reduced the hepatocyte ATP level. This effect was partially counteracted by SIRT3 overexpression. Furthermore, metformin decreased mitochondrial SIRT3 protein levels and this was associated with enhanced acetylation of several mitochondrial proteins. However, metformin increased mitochondrial mass in hepatocytes. Altogether, our results indicate that metformin attenuates mitochondrial expression of SIRT3 and suggest that this mechanism is involved in regulation of energymetabolism by metformin in the liver and may contribute to the therapeutic action of metformin.
normalizes with RSV. The DM group exhibited higher myocardial b-hydroxyacyl coenzyme-A dehydrogenase and citrate synthase activity, and RSV decreased the activity of these enzymes. The DM group had higher cardiac lactate dehydrogenase compared to the DM-RSV group. Myocardial protein carbonyl was increased in the DM group. RSV increased reduced glutathione in the cardiac tissue of diabetic animals. The glutathione reductase activity was higher in the DM-RSV group compared to the DM group. In conclusion, diabetes is accompanied by cardiac energymetabolism dysfunction and change in the biomarkers of oxidative stress. The cardioprotective effect may be mediated through RVS’s ability to normalize free fatty acid oxidation, enhance utilization glucose, and control the biomarkers’ level of oxidative stress under diabetic conditions.
Since various ‘Omics’ datasets are becoming available, biology has transited from a data-poor to a data-rich environment. Systems biology has become a rapidly growing field as well . Genome-scale models of metabolism have only been analyzed with the constraint- based modelling philosophy [2,3]. Genome-scale network models of diverse cellular processes have been generated and there have been several genome-scale GPR (gene-protein-reaction) models [4–10]. An extensive set of methods for analyzing these genome-scale models have also been developed and have also been applied to study a growing number of biological problems [12,13]. But research on the energymetabolism of organisms just begin in recent years, such as FVA (flux variability analysis) [14,15] and EBA (energy balance analysis) [16–18], and so on. All these methods are depended on the modelling of energymetabolism system of organisms. Data of Gibbs free energy of formation of every compound and Gibbs free energy change of every reaction is the core in this kind of modelling. Up to now, the most detailed genome-scale GPR model is the iAF1260 version of E. coli , but the modelling of it’s energymetabolism is still incomplete . There are 2381 reactions (not including the reaction defined for growth) and 1039 metabolites in E. coli_iAF1260, and apart from 304 EX_ & DM_ reactions (The text ‘EX_’ denotes an exchange reaction for a metabolite that can enter or leave the extra- cellular compartment. ‘DM_’ reactions are similar and signify compounds that the degradation pathway is unknown), the reconstructed reaction number is 2077 . By the newest group
Thus, the typical standard diet in obesity consists of high calorie and fat consumption and low intake of antioxidant nutrients [6, 18, 19] which promote an increase in free fatty acids plasma concentrations. Therefore, in the WAT, mitochondria do not perform their normal functions, getting overloaded and resulting in incomplete β-oxidation of fatty acids. This predisposes the homeostasis loss and increases the reactive oxygen species (ROS) production, triggering oxidative stress status. These changes lead to cells deterioration, resulting in insulin resistance or in a greater lipid accumulation in adipocytes, due to the increased nicotinamide adenine dinucleotide phosphate- reduced (NADPH) supply, predisposing to obesity by changes in energymetabolism [4, 20] .
The comparative genomic analysis reported in this work provides new insights into the energymetabolism of SRO. By comparing phylogenetically distinct organisms capable of sulfate reduction we identified the proteins that can be considered as comprising the minimal set required for this metabolic activity: a sulfate trans- porter, Sat, a pyrophosphatase, AprAB, DsrAB, DsrC, DsrMK, and Fd. The QmoAB proteins are also present in most organisms, being absent only in C. maquiligensis. In addition, we identified a higher diversity of possible energy conserving pathways than classically has been considered to be present in these organisms. The intracellular redox cycling of metabolites (like H 2 , formate or CO) is not a universal mechanism, but should play a role in bioenergetics of Deltaproteobacteria and T. yellowstonii, which are characterized by a large number of cytochromes c and cyto- chrome c-associated membrane redox complexes. A large number of cytochromes c has previously been correlated with increased respiratory versatility in anaerobes (Thomas et al., 2008), and such versatility is also suggested by the apparent redundancy of periplasmic redox proteins and membrane complexes found in many Deltaproteobacteria. Redox cycling is associated with energy conservation though charge separation or redox loop mechanisms. In contrast, the Archaea and Clostridia groups contain practically no cytochromes c or associated membrane complexes. The Gram- positive organisms analyzed present some unique traits including the absence of QmoC and DsrJOP proteins. Despite the absence of a periplasmic space, three extracytoplasmic proteins are predicted for these organisms, namely NrfHA and membrane-anchored [FeFe] Hase and FDH.
The Coo hydrogenase appears to participate in the energymetabolism when lactate is the electron donor. Transcriptional arrays showed that gene expression of this enzyme is among the top 15% of expressed genes during lactate/sulfate growth and it is up-regulated when compared to pyruvate/sulfate conditions (Keller and Wall, 2011) Furthermore, random transposon mutant libraries indicated that the Coo complex is essential in lactate metabolism, as no insertion in the coo operon was observed in cells growing in lactate/sulfate conditions. Based on these results, Keller and Wall proposed that this hydrogenase may allow the bifurcation of electrons from reduced ferredoxin and menaquinone. However, there is no clear evidence to support this idea. In contrast, in other analysis performed in D. vulgaris Hildenborough the Coo hydrogenase was proposed to participate, together with carbon moxonide dehydrogenase (CODH), in CO cycling during growth using pyruvate as the electron donor (Voordouw, 2002). This mechanism would constitute another metabolic cycling mechanism to conserve energy besides hydrogen and formate cycling. In agreement, in a D. vulgaris Hildenborough coo deletion mutant strain it was shown that despite the up-regulation obtained in transcriptional arrays, the Coo hydrogenase was not required for lactate/sulfate respiratory growth (Walker et al., 2009) . In this analysis, the Coo hydrogenase was proposed to produce H 2 and perform an important role
Temperature and salinity are important abiotic factors for aquatic invertebrates. We investigated the influence of different salinity regimes on thermotolerance, energymetabolism and cellular stress defense mechanisms in amphipods Gammarus lacustris Sars from two populations. We exposed amphipods to different thermal scenarios and determined their survival as well as activity of major antioxidant enzymes (peroxidase, catalase, glutathione S-transferase) and parameters of energymetabolism (content of glucose, glycogen, ATP, ADP, AMP and lactate). Amphipods from a freshwater population were more sensitive to the thermal challenge, showing higher mortality during acute and gradual temperature change compared to their counterparts from a saline lake. A more thermotolerant population from a saline lake had high activity of antioxidant enzymes. The energy limitations of the freshwater population (indicated by low baseline glucose levels, downward shift of the critical temperature of aerobic metabolism and inability to maintain steady-state ATP levels during warming) was ob- served, possibly reflecting a trade-off between the energy demands for osmoregulation under the hypo-osmotic condition of a freshwater environment and protection against temperature stress.
oncogenes and other tumor-related factors, is a critical factor in determining the clinical phenotypes of cancer. The molecu- lar carcinogenesis of thyroid cancer has advanced tremen- dously in the last decade [1-6]. However, the role and nature of energymetabolism in thyroid cancer remain unclear. Mitochondria provide 90% of the cellular energy required for various biological functions through oxidative phosphory- lation (OxPhos) in the inner mitochondrial membrane . In addition, mitochondria regulate cellular metabolism, including steroid hormone and porphyrin synthesis, the urea cycle, lipid metabolism, and interconversion of amino acids . They also play central roles in apoptosis, cell proliferation, and cellular
The metabolic profiles of selected tissues were analyzed in hatchlings of the Amazonian freshwater turtles Podocnemis expansa, P. unifilis and P. sextuberculata. Metabolic design in these species was judged based on the key enzymes of energymetabolism, with special emphasis on carbohydrate, lipid, amino acid and ketone body metabolism. All spe- cies showed a high glycolytic potential in all sampled tissues. Based on low levels of hexokinase, glycogen may be an important fuel for these species. The high lactate dehydrogenase activity in the liver may play a significant role in carbohydrate catabolism, possibly during diving. Oxidative metabolism in P. sextuberculata appears to be designed for the use of lipids, amino acids and ketone bodies. The maximal activities of 3-hydroxyacyl-CoA dehydrogenase, malate dehydrogenase, glutamine dehydrogenase, alanine aminotransferase and succinyl-CoA keto transferase display high aerobic potential, especially in muscle and liver tissues of this species. Although amino acids and ketone bodies may be important fuels for oxidative metabolism, carbohydrates and lipids are the major fuels used by P. expansa and P. unifilis. Our results are consistent with the food habits and lifestyle of Amazonian freshwater turtles. The metabolic design, based on enzyme activities, suggests that hatchlings of P. unifilis and P. expansa are predominately herbivo- rous, whereas P. sextuberculata rely on a mixed diet of animal matter and vegetation.
energymetabolism carried out on a rat model of chronic hepatic encephalopathy. This rather new approach gets together 1 H MRS and 31 P MRS studies tracking metabolite concentration at several stages of disease and giving insight on cerebral developments over progression of chronic HE. Therefore, it is important to thoroughly understand the processes involved in this study. Some previous in vivo MRS studies focused mostly a smaller time frame only with stages after 4 weeks and shorter than 8 weeks (Chavarria et al., 2013). Similarly to the present study, they were done at lower magnetic fields (7T) but just focusing on a small number of metabolites (Gln, Glu, Cr, Cho, Lac, NAA, Ins). The present study was performed ar 9.4T with the detection and tracking changes on 21 metabolites.
Membrane respiratory complexes are of extreme importance for life as they are the link to for energy conservation in living organisms. There are two essential membrane complexes for sulfate reduction present in all SRP and also some SOB, DsrMKJOP and QmoABC (Frigaard & Dahl, 2009, Pereira et al., 2011). The QmoABC complex is thought to exchange electrons with the ApsBA (APS reductase) and DsrMKJOP is proposed to reduce the trisulfide form of DsrC. The DsrMKJOP membrane complex was first purified from A. fulgidus in 2002 by Mander and coworkers (Mander et al., 2002), where it was named Hme for Hdr- like menaquinone-oxidizing enzyme (Hme). A homologue to Hme complex was also discovered in A. vinosum by Dahl et al (Dahl et al., 2005). It was found to be part of an essential operon for sulfur oxidation coupled with the dsrAB genes, and for this reason was named DsrMKJOP complex. In 2006, Pires et al purified the DsrMKJOP complex from D. desulfuricans ATCC 27774 which was shown to be a homologue of the Hme complex of A. fulgidus (Pires et al., 2006). This complex is formed by five subunits. One cytoplasmic subunit, DsrK, thought to be the catalytic subunit of DsrMKJOP complex due to its homology to HdrD, which is responsible for heterodisulfide reduction by the membrane-bound HdrDE complex. Two membrane bound subunits (DsrM and DsrP), possibly responsible for menaquinol interaction, and two periplasmic facing membrane bound proteins (DsrO and DsrJ) (Pires et al., 2006, Grein, 2010). DsrJ contains three heme binding motives CXXCH, in which one of these hemes is characterized by an unusual His/Cys heme distal axial ligation (Pires et al., 2006, Grein et al., 2010). In the DsrMKJOP from D. desulfuricans a redox potential of - 400 mV and a very unique peak g max 2.47 for the EPR spectra were attributed to
Over the last decade, sirtuins have been considered as key players in multiple cellular events. They are ubiquitously expressed in mammalian tissues and cells and are particularly abundant in the testicular tissue. Indeed, for all SIRT genes, testis is among the adult organs where their mRNAs abundances is the highest, particularly SIRT1 expression (120). Thus, it is reasonable to hypothesize that the presence of endogenous SIRT1 has a specific function on testicular metabolism regulation. SIRT1 is mostly a nuclear protein, however sometimes it can be found in the cytoplasm. Several studies have highlighted the importance of SIRT1 on the testicular environment. It has been reported that this sirtuin controls male fertility through regulation of HPT axis, which impacts LCs and SCs maturation (143), as well as in anatomically aspects of the testes size, and on sperm quality (121).
The main effect of insulin on carbohydrate metabolism is to enable the transport of glucose across the cell membrane. Also, it stimulates lipogenesis and hepatic synthesis of glycogen (Reece, 2008). According to McKeever (2002), the insulin response to intense exercise is well documented on horses; like humans and other species, it has low insulin concentration during physical activity mainly because cortisol and cathecolamines are in action. A lower concentration of insulin enables an increased gluconeogenesis in order to maintain blood glucose in higher concentrations during exercise. The suppression of insulin and a resulting higher glucose concentration in the blood prevent the emergence of central mechanisms of fatigue (McKeever, 2002).
In this work, we demonstrated that AgN inhibited brain and skeletal muscle CK in vitro. On the other hand, heart CK was not affected in vitro by AgN. Further studies are important to evaluate whether other enzymes involved in metabolism are also affected by AgN. Moreover, the in vivo effect of AgN on energymetabolism is also being evaluated.
PCr/ATP ratios in healthy males might be a function of age. which is probably due to mitochondrial ageing in heart muscle cells. A reduction of PCr/ATP is further associated with increasing myocardial mass and decrease in the E/A ratio in healthy volunteers, whereby the relationship between age and myocardial mass as well as E/A ratio corresponds to the literature, as mentioned above. However, this study is the first to demonstrate the relationship between myocardial energymetabolism and structural alterations in healthy humans. Therefore, we can speculate that the maximal lifespan is reached, when the left- ventricular PCr/ATP ratio is about zero. However, we also know from previous work that exercise capacity and cardiovascular risk factors can modify this ratio, which is an excellent indicator for the efficiency of energymetabolism within the myocardium. Accord- ingly, a previous study has shown that the mitochondrial oxidant production can be reduced by chronic exercise . Since age remains still one of the most important cardiovascular risk factors,
Methodology/Principal Findings: A urinary metabonomic method based on ultra performance liquid chromatography coupled to mass spectrometry was employed to explore global metabolic characters of hypothyroidism. Three typical hypothyroidism models (methimazole-, propylthiouracil- and thyroidectomy-induced hypothyroidism) were applied to elucidate the molecular mechanism of hypothyroidism. 17, 21, 19 potential biomarkers were identified with these three hypothyroidism models respectively, primarily involved in energymetabolism, amino acid metabolism, sphingolipid metabolism and purine metabolism. In order to avert the interference of drug interaction between the antithyroid drugs and SND, the thyroidectomy-induced hypothyroidism model was further used to systematically assess the therapeutic efficacy of SND on hypothyroidism. A time-dependent recovery tendency was observed in SND-treated group from the beginning of model to the end of treatment, suggesting that SND exerted a recovery effect on hypothyroidism in a time- dependent manner through partially regulating the perturbed metabolic pathways.
In addition, the respiratory chain is an important pillar in sepsis pathophysiology. Because mitochondria play a critical role in cellular energy production via electron transport chain-dependent synthesis of ATP through oxidative phosphorylation and are the main site of ROS production, inlammatory insult results in mitochondria being damaged functionally and structurally. We previously performed a time-course experiment to evaluate the activities of mitochondrial respiratory chain complexes I, II, III and IV and creatine kinase after CLP; we demonstrated that brain energymetabolism is altered six and twelve hours after CLP. (36)
1) 117 genes were differentially expressed among neonates with and without subsequent neurocognitive impairment (p<0.05 and fold change >1.5); 2) Gene ontology analysis indi- cated enrichment of 19 biological processes and 3 molecular functions; 3)PADOG identified 4 significantly perturbed KEGG pathways: oxidative phosphorylation, Parkinson’s disease, Alzheimer’s disease and Huntington’s disease (q-value <0.1); 4) 48 of 90 selected differen- tially expressed genes were confirmed by qRT-PCR, including genes implicated in energymetabolism, neuronal signaling, vascular permeability and response to injury (e.g., up-regu- lation of SEPP1, APOE, DAB2, CD163, CXCL12, VWF; down-regulation of HAND1, OSR1) (p<0.05); and 5) a multi-gene model predicted 18–24 month neurocognitive impairment (using the ratios of OSR1/VWF and HAND1/VWF at birth) in a larger, independent set (sen- sitivity = 74%, at specificity = 83%).