PubMed

Metabolic signatures of bacterial vaginosis. MBio. 2015;6(2) Authors: Srinivasan S, Morgan MT, Fiedler TL, Djukovic D, Hoffman NG, Raftery D, Marrazzo JM, Fredricks DN Abstract UNLABELLED: Bacterial vaginosis (BV) is characterized by shifts in the vaginal microbiota from Lactobacillus dominant to a microbiota with diverse anaerobic bacteria. Few studies have linked specific metabolites with bacteria found in the human vagina. Here, we report dramatic differences in metabolite compositions and concentrations associated with BV using a global metabolomics approach. We further validated important metabolites using samples from a second cohort of women and a different platform to measure metabolites. In the primary study, we compared metabolite profiles in cervicovaginal lavage fluid from 40 women with BV and 20 women without BV. Vaginal bacterial representation was determined using broad-range PCR with pyrosequencing and concentrations of bacteria by quantitative PCR. We detected 279 named biochemicals; levels of 62% of metabolites were significantly different in women with BV. Unsupervised clustering of metabolites separated women with and without BV. Women with BV have metabolite profiles marked by lower concentrations of amino acids and dipeptides, concomitant with higher levels of amino acid catabolites and polyamines. Higher levels of the signaling eicosanoid 12-hydroxyeicosatetraenoic acid (12-HETE), a biomarker for inflammation, were noted in BV. Lactobacillus crispatus and Lactobacillus jensenii exhibited similar metabolite correlation patterns, which were distinct from correlation patterns exhibited by BV-associated bacteria. Several metabolites were significantly associated with clinical signs and symptoms (Amsel criteria) used to diagnose BV, and no metabolite was associated with all four clinical criteria. BV has strong metabolic signatures across multiple metabolic pathways, and these signatures are associated with the presence and concentrations of particular bacteria. IMPORTANCE: Bacterial vaginosis (BV) is a common but highly enigmatic condition that is associated with adverse outcomes for women and their neonates. Small molecule metabolites in the vagina may influence host physiology, affect microbial community composition, and impact risk of adverse health outcomes, but few studies have comprehensively studied the metabolomics profile of BV. Here, we used mass spectrometry to link specific metabolites with particular bacteria detected in the human vagina by PCR. BV was associated with strong metabolic signatures across multiple pathways affecting amino acid, carbohydrate, and lipid metabolism, highlighting the profound metabolic changes in BV. These signatures were associated with the presence and concentrations of particular vaginal bacteria, including some bacteria yet to be cultivated, thereby providing clues as to the microbial origin of many metabolites. Insights from this study provide opportunities for developing new diagnostic markers of BV and novel approaches for treatment or prevention of BV. PMID: 25873373 [PubMed - in process]

Constitutive production of c-di-GMP is associated with mutations in a variant of Pseudomonas aeruginosa with altered membrane composition. Sci Signal. 2015;8(372):ra36 Authors: Blanka A, Düvel J, Dötsch A, Klinkert B, Abraham WR, Kaever V, Ritter C, Narberhaus F, Häussler S Abstract Most bacteria can form multicellular communities called biofilms on biotic and abiotic surfaces. This multicellular response to surface contact correlates with an increased resistance to various adverse environmental conditions, including those encountered during infections of the human host and exposure to antimicrobial compounds. Biofilm formation occurs when freely swimming (planktonic) cells encounter a surface, which stimulates the chemosensory-like, surface-sensing system Wsp and leads to generation of the intracellular second messenger 3',5'-cyclic-di-guanosine monophosphate (c-di-GMP). We identified adaptive mutations in a clinical small colony variant (SCV) of Pseudomonas aeruginosa and correlated their presence with self-aggregating growth behavior and an enhanced capacity to form biofilms. We present evidence that a point mutation in the 5' untranslated region of the accBC gene cluster, which encodes components of an enzyme responsible for fatty acid biosynthesis, was responsible for a stabilized mRNA structure that resulted in reduced translational efficiency and an increase in the proportion of short-chain fatty acids in the plasma membrane. We propose a model in which these changes in P. aeruginosa serve as a signal for the Wsp system to constitutively produce increased amounts of c-di-GMP and thus play a role in the regulation of adhesion-stimulated bacterial responses. PMID: 25872871 [PubMed - in process]

Alcoholic liver disease: the gut microbiome and liver cross talk. Alcohol Clin Exp Res. 2015 May;39(5):763-75 Authors: Hartmann P, Seebauer CT, Schnabl B Abstract Alcoholic liver disease (ALD) is a leading cause of morbidity and mortality worldwide. Alcoholic fatty liver disease can progress to steatohepatitis, alcoholic hepatitis, fibrosis, and cirrhosis. Patients with alcohol abuse show quantitative and qualitative changes in the composition of the intestinal microbiome. Furthermore, patients with ALD have increased intestinal permeability and elevated systemic levels of gut-derived microbial products. Maintaining eubiosis, stabilizing the mucosal gut barrier, or preventing cellular responses to microbial products protect from experimental ALD. Therefore, intestinal dysbiosis and pathological bacterial translocation appear fundamental for the pathogenesis of ALD. This review highlights causes for intestinal dysbiosis and pathological bacterial translocation, their relationship, and consequences for ALD. We also discuss how the liver affects the intestinal microbiota. PMID: 25872593 [PubMed - in process]

The quantity-effect relationship and physiological mechanisms of different acupuncture manipulations on posterior circulation ischemia with vertigo: study protocol for a randomized controlled trial. Trials. 2015;16(1):152 Authors: Deng SZ, Zhao XF, Huang LH, He S, Wen Y, Zhang C, Tian G, Wang T, Wu FF, Meng ZH, Shi XM Abstract BACKGROUND: Recent experiments have demonstrated that different needling manipulations may induce variable effects via diverse physiological mechanisms. A previous study indicated that needling at Fengchi (GB 20) improved cerebral blood flow in patients with vertigo induced by posterior circulation ischemia (PCI). In this study, we aim to explore the quantity-effect relationship and the physiological mechanisms underlying different acupuncture manipulations in PCI patients with vertigo. METHODS/DESIGN: We propose a pragmatic randomized and controlled trial. All participants, outcome assessors, and statisticians will be blinded. A total of 144 eligible participants will be randomized into one of four treatment groups receiving acupuncture at Fengchi (GB 20) with different one-minute manipulation parameters. Group 1 will receive twirling at a frequency of 60 times per minute toward the contralateral outer canthus at a depth of 0.5 to 0.8 cun. Group 2 will receive twirling at a frequency of 60 times per minute toward the Adam's apple at a depth of 0.5 to 0.8 cun. Group 3 will receive twirling at a frequency of 120 times per minute toward the contralateral outer canthus at a depth of 0.5 to 0.8 cun. Group 4 will receive twirling at a frequency of120 times per minute toward the Adam's apple at a depth of 0.5 to 0.8 cun. Additional points will be added based on individualized pattern diagnoses. The participants will receive 14 acupuncture sessions over 3 to 4 weeks. The subjects will be assessed at two time points: baseline and post-treatment. The primary outcome measurements will include subjective measurements (Vertebrobasilar System Ischemic Neurological Impairment Scale, UCLA Dizziness Questionnaire, Activities of Daily Living Scale, and Psychological and Social Adaptation Scale) and objective measurements (Transcranial Doppler, carotid ultrasonography and changes in cerebral oxygenation) to reduce bias arising from the placebo effect. We will use metabolomics to investigate the mechanisms underlying the different manipulation parameters. DISCUSSION: This trial aims to explore the quantity-effect relationship between different acupuncture manipulations and their clinical effects. The results from this study may help explain the contradictory results found in acupuncture studies that practice different manipulations. TRIAL REGISTRATION: Chinese Clinical Trial Registry: ChiCTR-RTRCC-12002675 (registered on 14 November 2012). PMID: 25872507 [PubMed - in process]

Related Articles A gut microbial metabolite of linoleic acid, 10-hydroxy-cis-12-octadecenoic acid, ameliorates intestinal epithelial barrier impairment partially via GPR40-MEK-ERK pathway. J Biol Chem. 2015 Jan 30;290(5):2902-18 Authors: Miyamoto J, Mizukure T, Park SB, Kishino S, Kimura I, Hirano K, Bergamo P, Rossi M, Suzuki T, Arita M, Ogawa J, Tanabe S Abstract Gut microbial metabolites of polyunsaturated fatty acids have attracted much attention because of their various physiological properties. Dysfunction of tight junction (TJ) in the intestine contributes to the pathogenesis of many disorders such as inflammatory bowel disease. We evaluated the effects of five novel gut microbial metabolites on tumor necrosis factor (TNF)-α-induced barrier impairment in Caco-2 cells and dextran sulfate sodium-induced colitis in mice. 10-Hydroxy-cis-12-octadecenoic acid (HYA), a gut microbial metabolite of linoleic acid, suppressed TNF-α and dextran sulfate sodium-induced changes in the expression of TJ-related molecules, occludin, zonula occludens-1, and myosin light chain kinase. HYA also suppressed the expression of TNF receptor 2 (TNFR2) mRNA and protein expression in Caco-2 cells and colonic tissue. In addition, HYA suppressed the protein expression of TNFR2 in murine intestinal epithelial cells. Furthermore, HYA significantly up-regulated G protein-coupled receptor (GPR) 40 expression in Caco-2 cells. It also induced [Ca(2+)]i responses in HEK293 cells expressing human GPR40 with higher sensitivity than linoleic acid, its metabolic precursor. The barrier-recovering effects of HYA were abrogated by a GPR40 antagonist and MEK inhibitor in Caco-2 cells. Conversely, 10-hydroxyoctadacanoic acid, which is a gut microbial metabolite of oleic acid and lacks a carbon-carbon double bond at Δ12 position, did not show these TJ-restoring activities and down-regulated GPR40 expression. Therefore, HYA modulates TNFR2 expression, at least partially, via the GPR40-MEK-ERK pathway and may be useful in the treatment of TJ-related disorders such as inflammatory bowel disease. PMID: 25505251 [PubMed - indexed for MEDLINE]

Related Articles Identification, characterization, and structure analysis of the cyclic di-AMP-binding PII-like signal transduction protein DarA. J Biol Chem. 2015 Jan 30;290(5):3069-80 Authors: Gundlach J, Dickmanns A, Schröder-Tittmann K, Neumann P, Kaesler J, Kampf J, Herzberg C, Hammer E, Schwede F, Kaever V, Tittmann K, Stülke J, Ficner R Abstract The cyclic dimeric AMP nucleotide c-di-AMP is an essential second messenger in Bacillus subtilis. We have identified the protein DarA as one of the prominent c-di-AMP receptors in B. subtilis. Crystal structure analysis shows that DarA is highly homologous to PII signal transducer proteins. In contrast to PII proteins, the functionally important B- and T-loops are swapped with respect to their size. DarA is a homotrimer that binds three molecules of c-di-AMP, each in a pocket located between two subunits. We demonstrate that DarA is capable to bind c-di-AMP and with lower affinity cyclic GMP-AMP (3'3'-cGAMP) but not c-di-GMP or 2'3'-cGAMP. Consistently the crystal structure shows that within the ligand-binding pocket only one adenine is highly specifically recognized, whereas the pocket for the other adenine appears to be promiscuous. Comparison with a homologous ligand-free DarA structure reveals that c-di-AMP binding is accompanied by conformational changes of both the fold and the position of the B-loop in DarA. PMID: 25433025 [PubMed - indexed for MEDLINE]

Related Articles Ergosterol, an orphan fungal microbe-associated molecular pattern (MAMP). Mol Plant Pathol. 2014 Sep;15(7):747-61 Authors: Klemptner RL, Sherwood JS, Tugizimana F, Dubery IA, Piater LA Abstract Fungal pathogens continue to pose a significant threat to crop production and food supply. The early stages of plant-fungus interactions are mostly mediated by microbe-associated molecular pattern (MAMP) molecules, perceived by plant pattern recognition receptors (PRRs). Currently, the identified fungal MAMP molecules include chitin, chitosan, β-glucans, elicitins and ergosterol. Although the molecular battles between host plants and infecting fungal phytopathogens have been studied extensively, many aspects still need to be investigated to obtain a holistic understanding of the intrinsic mechanisms, which is paramount in combating fungal plant diseases. Here, an overview is given of the most recent findings concerning an 'orphan' fungal MAMP molecule, ergosterol, and we present what is currently known from a synopsis of different genes, proteins and metabolites found to play key roles in induced immune responses in plant-fungus interactions. Clearly, integrative investigations are still needed to provide a comprehensive systems-based understanding of the dynamics associated with molecular mechanisms in plant-ergosterol interactions and associated host responses. PMID: 24528492 [PubMed - indexed for MEDLINE]

Related Articles A High-Performance Liquid Chromatography- Tandem Mass Spectrometry- Based Targeted Metabolomics Kidney Dysfunction Marker Panel in Human Urine. Clin Chim Acta. 2015 Apr 11; Authors: Klepacki J, Klawitter J, Klawitter J, Thurman J, Christians U Abstract BACKGROUND: Previous studies have examined and documented fluctuations in urine metabolites in response to disease processes and drug toxicity affecting glomerular filtration, tubule cell metabolism, reabsorption, oxidative stress, purine degradation, active secretion and kidney amino acylase activity representative of diminished renal function. However, a high-throughput assay that incorporates metabolites that are surrogate markers for such changes into a kidney dysfunction panel has yet to be described. METHODS: A high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) assay for the quantification of ten metabolites associated with the Krebs cycle, purine degradation, and oxidative stress in human urine was developed and validated. Normal values were assessed in healthy adult (n=120) and pediatric (n=36) individuals. In addition, 9 pediatric renal transplant recipients patients were evaluated before and after initial dosing of the immunosuppressant tacrolimus in a proof-of-concept study. RESULTS: The assay met all predefined acceptance criteria. The lower limit of quantification ranged from 0.1 to 1000 μmol/l. Inter-day trueness and imprecisions ranged from 91.4-112.9% and 1.5-12.4%, respectively. The total assay run time was 5.5 minutes. Concentrations of glucose, sorbitol, and trimethylamine oxide (TMAO) were elevated in pediatric renal transplant patients (n=9) prior to transplantation as well as before and immediately after initial dosing of tacrolimus. One month post-transplant urine metabolite patterns matched those of healthy children (n=36). CONCLUSIONS: The LC-MS/MS assay will provide the basis for further large-scale clinical studies to explore these analytes as molecular markers for the patients with renal insufficiency. PMID: 25871999 [PubMed - as supplied by publisher]

Related Articles Metabolomic Signatures for Drug Response Phenotypes-Pharmacometabolomics Enables Precision Medicine. Clin Pharmacol Ther. 2015 Apr 14; Authors: Kaddurah-Daouk R, Weinshilboum R, Pharmacometabolomics Research Network Abstract The scaling up of data in clinical pharmacology and the merger of systems biology and pharmacology has led to the emergence of a new discipline of Quantitative and Systems Pharmacology (QSP). This new research direction might significantly advance the discovery, development and clinical use of therapeutic drugs. Research communities from computational biology, systems biology and biological engineering-working collaboratively with pharmacologists, geneticists, biochemists and analytical chemists-are creating and modeling large data on drug effects that is transforming our understanding of how these drugs work at a network level. In this review, we highlight developments in a new and rapidly growing field-pharmacometabolomics-in which large biochemical data-capturing effects of genome, gut microbiome and environment exposures is revealing information about metabotypes and treatment outcomes, and creating metabolic signatures as new potential biomarkers. Pharmacometabolomics informs and compliments pharmacogenomics and together they provide building blocks for QSP. This article is protected by copyright. All rights reserved. PMID: 25871646 [PubMed - as supplied by publisher]

Related Articles Blood Metabolome Changes Before and After Bariatric Surgery: A (1)H NMR-Based Clinical Investigation. OMICS. 2015 Apr 14; Authors: Lopes TI, Geloneze B, Pareja JC, Calixto AR, Ferreira MM, Marsaioli AJ Abstract Excessive body fat and obesity have adverse health effects and result in significant morbidity such as type 2 diabetes mellitus. The health burden of obesity can be reduced with the Roux-en-Y gastric bypass (RYGB) weight-loss bariatric surgery. Little is known on the molecular changes that occur at the metabolome level before and after bariatric surgery, with a view to clinical biomarker development. Hence, we employed a metabolomics approach in 10 obese diabetic patients who underwent bariatric surgery. Metabolomics data were obtained by T2- and diffusion-edited hydrogen nuclear magnetic resonance ((1)H NMR) spectra to monitor the metabolic and lipoprotein profiles, and gas chromatography-mass spectrometry (CG-MS) to access the fatty acid profile before and 12 months after RYGB. Using hierarchical partial least squares discriminant analysis, we found that RYGB induces several key metabolic alterations associated with glucose homeostasis, as well as fatty acid and amino acid metabolism. The levels of lactate (Krebs' intermediate cycle) decreased after RYGB. The leucine, isoleucine, valine, lactate, and glucose levels were higher in the samples before RYGB (p<0.05). Additionally, the levels of very low-density lipoprotein, unsaturated lipids, and N-acetyl-glycoprotein were higher before RYGB. By contrast, levels of the high-density lipoprotein and phosphatidylcholine were higher after bariatric surgery. These results collectively offer important holistic integrative biology data to develop future clinically relevant metabolomics biomarkers related to bariatric surgery in connection with obesity. PMID: 25871626 [PubMed - as supplied by publisher]

Related Articles Urinary metabolomics and biomarkers of aristolochic acid nephrotoxicity by UPLC-QTOF/HDMS. Bioanalysis. 2015 Apr;7(6):685-700 Authors: Zhao YY, Tang DD, Chen H, Mao JR, Bai X, Cheng XH, Xiao XY Abstract BACKGROUND: Drug-induced nephrotoxicity was one of the most important health problems, with increasing morbidity and mortality. Urinary metabolomics based on ultra performance liquid chromatography coupled with quadrupole time-of-flight high-definition mass spectrometry was applied to aristolochic acid (AA) nephrotoxicity rats to characterize the excretion pathways of endogenous metabolites. RESULTS: Compared with the control rats, serum creatinine, serum blood urea nitrogen and urine protein levels were significantly increased in AA nephrotoxicity rats. Metabolomics showed that metabolites including citrate, aconitate, fumarate, glucose, creatinine, p-cresyl sulfate, indoxyl sulfate, hippuric acid, phenylacetylglycine, kynurenic acid, indole-3-carboxylic acid, spermine, uric acid, allantoin, cholic acid and taurine were identified in AA nephrotoxicity rats. CONCLUSION: The identified metabolites suggested that AA nephrotoxicity rats occurred perturbations in Krebs cycle, gut microflora metabolism, amino acid metabolism, purine metabolism and bile acid biosynthesis. PMID: 25871586 [PubMed - as supplied by publisher]

Related Articles What role can metabolomics play in the discovery and development of new medicines for infectious diseases? Bioanalysis. 2015 Apr;7(6):629-631 Authors: Kim DH, Creek DJ PMID: 25871581 [PubMed - as supplied by publisher]

Related Articles Metabolic phenotyping of the Yersinia high-pathogenicity island that regulates central carbon metabolism. Analyst. 2015 Apr 14; Authors: Yan L, Nie W, Lv H Abstract The high-pathogenicity island (HPI) is an important determinant of the pathogenicity of pathogenic Yersinia microbes. The HPI carries a cluster of virulence genes that chiefly account for the biosynthesis, transportation and regulation of a virulence-associated siderophore, yersiniabactin. This siderophore is also present in uropathogenic E. coli (UTI89) but not in non-uropathogenic E. coli. We sought to perform metabolic phenotyping and to understand how the presence of the HPI influences central carbon metabolism, which remains poorly understood, by combining targeted metabolomics with a genetic approach. Unexpectedly, our results revealed that uropathogenic E. coli (UPEC) with an HPI had superior metabolic homeostasis to a non-UPEC K12 strain without an HPI, thereby allowing UPEC with an HPI to flexibly adapt to a variety of growth environments. In this study, we elucidate the unrecognized regulatory effects of the HPI virulence genes on central carbon metabolism, in addition to their roles in directing yersiniabactin. These regulatory effects may be implicated in differentiating UPEC from non-UPEC. PMID: 25870861 [PubMed - as supplied by publisher]

Related Articles Simultaneous analysis of multiple neurotransmitters by hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry. J Chromatogr A. 2015 Mar 30; Authors: Tufi S, Lamoree M, de Boer J, Leonards P Abstract Neurotransmitters are endogenous metabolites that allow the signal transmission across neuronal synapses. Their biological role is crucial for many physiological functions and their levels can be changed by several diseases. Because of their high polarity, hydrophilic interaction liquid chromatography (HILIC) is a promising tool for neurotransmitter analysis. Due to the large number of HILIC stationary phases available, an evaluation of the column performances and retention behaviors has been performed on five different commercial HILIC packing materials (silica, amino, amide and two zwitterionic stationary phases). Several parameters like the linear correlation between retention and the distribution coefficient (logD), the separation factor k and the column resolution Rs have been investigated and the column performances have been visualized with a heat map and hierarchical clustering analysis. An optimized and validated HILIC-MS/MS method based on the ZIC-cHILIC column is proposed for the simultaneous detection and quantification of twenty compounds consisting of neurotransmitters, precursors and metabolites: 3-methoxytyramine (3-MT), 5-hydroxyindoleacetic acid (5-HIAA), 5-hydroxy-L-tripthophan, acetylcholine, choline, L-3,4-dihydroxyphenylalanine (L-DOPA), dopamine, epinephrine, γ-aminobutyric acid (GABA), glutamate, glutamine, histamine, histidine, L-tryptophan, L-tyrosine, norepinephrine, normetanephrine, phenylalanine, serotonin and tyramine. The method was applied to neuronal metabolite profiling of the central nervous system of the freshwater snail Lymnaea stagnalis. This method is suitable to explore neuronal metabolism and its alteration in different biological matrices. PMID: 25869798 [PubMed - as supplied by publisher]

Related Articles Untargeted Metabolic Profiling of Vitis vinifera during Fungal Degradation. FEMS Microbiol Lett. 2015 Apr 13; Authors: Karpe AV, Beale DJ, Morrison PD, Harding IH, Palombo EA Abstract This paper illustrates the application of an untargeted metabolic profiling analysis of winery-derived biomass degraded using four filamentous fungi (Trichoderma harzianum, Aspergillus niger, Penicillium chrysogenum and Penicillium citrinum) and a yeast (Saccharomyces cerevisiae). Analysis of the metabolome resulted in the identification of 233 significant peak features (p<0.05; Fold Change [FC]>2 and signal to noise ratio >50) using gas chromatography-mass spectrometry (GC-MS) followed by statistical chemometric analysis. Furthermore, A. niger and P. chrysogenum produced higher biomass degradation due to considerable β-glucosidase and xylanase activities. The major metabolites generated during fungal degradation which differentiated the metabolic profiles of fungi included sugars, sugar acids, organic acids and fatty acids. Although, P. chrysogenum could degrade hemicelluloses due to its high β-glucosidase and xylanase activities, it could not utilize the resultant pentoses, which A. niger and P. citrinum could do efficiently, thus indicating a need of mixed fungal culture to improve the biomass degradation. S. cerevisiae, a non-cellulose degrader, exhibited sugar accumulation during the fermentation. P. chrysogenum was observed to degrade about 2% lignin, a property not observed in other fungi. This study emphasized the differential fungal metabolic behaviour and demonstrated the potential of metabolomics in optimising degradation or manipulating pathways to increase yields of products of interest. PMID: 25868913 [PubMed - as supplied by publisher]

Related Articles Quorum sensing is accompanied by global metabolic changes in the opportunistic human pathogen, Pseudomonas aeruginosa. J Bacteriol. 2015 Apr 13; Authors: Davenport P, Griffin JL, Welch M Abstract Pseudomonas aeruginosa uses N-acyl-homoserine lactone (AHL)-dependent quorum sensing (QS) systems to control the expression of secreted effectors. These effectors can be crucial to the ecological fitness of the bacterium, playing roles in nutrient acquisition, microbial competition and virulence. In this study, we investigated the metabolic consequences of AHL-dependent QS by monitoring the metabolic profile(s) of a lasI rhlI double mutant (unable to make QS signaling molecules) and its wild-type progenitor as they progressed through the growth curve. Analysis of culture supernatants by (1)H-NMR spectroscopy revealed that at the point where AHL concentrations peaked in the wild-type, the metabolic footprints (i.e., extracellular metabolites) of the wild-type and lasI rhlI mutant diverged. Subsequent GCMS based analysis of the intracellular metabolome revealed QS-dependent perturbations in around one third of all identified metabolites, including altered concentrations of TCA cycle intermediates, amino acids and fatty acids. Further targeted FAME GCMS-based profiling of the cellular total fatty acid pools revealed that QS leads to changes associated with decreased membrane fluidity and higher chemical stability. However, not all of the changes we observed were necessarily a direct consequence of QS; LCMS analyses revealed that polyamine levels were elevated in the lasI rhlI mutant, perhaps a response to the absence of QS-dependent adaptations. Our data suggest that QS-leads to a global re-adjustment in central metabolism and provide new insight into the metabolic changes associated with QS during stationary phase adaptation. IMPORTANCE: Quorum sensing (QS) is a transcriptional regulatory mechanism that allows bacteria to coordinate their gene expression profile with the population cell density. The opportunistic human pathogen, Pseudomonas aeruginosa, uses QS to control the production of secreted virulence factors. In this study, we show that QS elicits a global "metabolic rewiring" in P. aeruginosa. This metabolic re-routing of fluxes is consistent with a variety of drivers, ranging from altered QS-dependent transcription of "metabolic genes", through to the effect(s) of global "metabolic readjustment" as a consequence of QS-dependent exoproduct synthesis, as well as a general stress response, among others. To our knowledge, this is the first study of its kind to assess the global impact of QS on the metabolome. PMID: 25868647 [PubMed - as supplied by publisher]

Related Articles Experimental strategies for functional annotation and metabolism discovery: targeted screening of solute binding proteins and unbiased panning of metabolomes. Biochemistry. 2015 Jan 27;54(3):909-31 Authors: Vetting MW, Al-Obaidi N, Zhao S, San Francisco B, Kim J, Wichelecki DJ, Bouvier JT, Solbiati JO, Vu H, Zhang X, Rodionov DA, Love JD, Hillerich BS, Seidel RD, Quinn RJ, Osterman AL, Cronan JE, Jacobson MP, Gerlt JA, Almo SC Abstract The rate at which genome sequencing data is accruing demands enhanced methods for functional annotation and metabolism discovery. Solute binding proteins (SBPs) facilitate the transport of the first reactant in a metabolic pathway, thereby constraining the regions of chemical space and the chemistries that must be considered for pathway reconstruction. We describe high-throughput protein production and differential scanning fluorimetry platforms, which enabled the screening of 158 SBPs against a 189 component library specifically tailored for this class of proteins. Like all screening efforts, this approach is limited by the practical constraints imposed by construction of the library, i.e., we can study only those metabolites that are known to exist and which can be made in sufficient quantities for experimentation. To move beyond these inherent limitations, we illustrate the promise of crystallographic- and mass spectrometric-based approaches for the unbiased use of entire metabolomes as screening libraries. Together, our approaches identified 40 new SBP ligands, generated experiment-based annotations for 2084 SBPs in 71 isofunctional clusters, and defined numerous metabolic pathways, including novel catabolic pathways for the utilization of ethanolamine as sole nitrogen source and the use of d-Ala-d-Ala as sole carbon source. These efforts begin to define an integrated strategy for realizing the full value of amassing genome sequence data. PMID: 25540822 [PubMed - indexed for MEDLINE]

Related Articles Systemic, cerebral and skeletal muscle ketone body and energy metabolism during acute hyper-D-β-hydroxybutyratemia in post-absorptive healthy males. J Clin Endocrinol Metab. 2015 Feb;100(2):636-43 Authors: Mikkelsen KH, Seifert T, Secher NH, Grøndal T, van Hall G Abstract CONTEXT: Ketone bodies are substrates during fasting and when on a ketogenic diet not the least for the brain and implicated in the management of epileptic seizures and dementia. Moreover, D-β-hydroxybutyrate (HOB) is suggested to reduce blood glucose and fatty acid levels. OBJECTIVES: The objectives of this study were to quantitate systemic, cerebral, and skeletal muscle HOB utilization and its effect on energy metabolism. DESIGN: Single trial. SETTING: Hospital. PARTICIPANT: Healthy post-absorptive males (n = 6). INTERVENTIONS: Subjects were studied under basal condition and three consecutive 1-hour periods with a 3-, 6-, and 12-fold increased HOB concentration via HOB infusion. MAIN OUTCOME MEASURES: Systemic, cerebral, and skeletal muscle HOB kinetics, oxidation, glucose turnover, and lipolysis via arterial, jugular, and femoral venous differences in combination with stable isotopically labeled HOB, glucose, and glycerol, infusion. RESULTS: An increase in HOB from the basal 160-450 μmol/L elicited 14 ± 2% reduction (P = .03) in glucose appearance and 37 ± 4% decrease (P = .03) in lipolytic rate while insulin and glucagon were unchanged. Endogenous HOB appearance was reduced in a dose-dependent manner with complete inhibition at the highest HOB concentration (1.7 mmol/L). Cerebral HOB uptake and subsequent oxidation was linearly related to the arterial HOB concentration. Resting skeletal muscle HOB uptake showed saturation kinetics. CONCLUSION: A small increase in the HOB concentration decreases glucose production and lipolysis in post-absorptive healthy males. Moreover, cerebral HOB uptake and oxidation rates are linearly related to the arterial HOB concentration of importance for modifying brain energy utilization, potentially of relevance for patients with epileptic seizures and dementia. PMID: 25415176 [PubMed - indexed for MEDLINE]

Related Articles Metabolic control of Ca2+/calmodulin-dependent protein kinase II (CaMKII)-mediated caspase-2 suppression by the B55β/protein phosphatase 2A (PP2A). J Biol Chem. 2014 Dec 26;289(52):35882-90 Authors: Huang B, Yang CS, Wojton J, Huang NJ, Chen C, Soderblom EJ, Zhang L, Kornbluth S Abstract High levels of metabolic activity confer resistance to apoptosis. Caspase-2, an apoptotic initiator, can be suppressed by high levels of nutrient flux through the pentose phosphate pathway. This metabolic control is exerted via inhibitory phosphorylation of the caspase-2 prodomain by activated Ca(2+)/calmodulin-dependent protein kinase II (CaMKII). We show here that this activation of CaMKII depends, in part, on dephosphorylation of CaMKII at novel sites (Thr(393)/Ser(395)) and that this is mediated by metabolic activation of protein phosphatase 2A in complex with the B55β targeting subunit. This represents a novel locus of CaMKII control and also provides a mechanism contributing to metabolic control of apoptosis. These findings may have implications for metabolic control of the many CaMKII-controlled and protein phosphatase 2A-regulated physiological processes, because both enzymes appear to be responsive to alterations in glucose metabolized via the pentose phosphate pathway. PMID: 25378403 [PubMed - indexed for MEDLINE]

Related Articles Plasma metabolic profiling analysis of nephrotoxicity induced by acyclovir using metabonomics coupled with multivariate data analysis. J Pharm Biomed Anal. 2014 Aug;97:151-6 Authors: Zhang X, Li Y, Zhou H, Fan S, Zhang Z, Wang L, Zhang Y Abstract Acyclovir (ACV) is an antiviral agent. However, its use is limited by adverse side effect, particularly by its nephrotoxicity. Metabonomics technology can provide essential information on the metabolic profiles of biofluids and organs upon drug administration. Therefore, in this study, mass spectrometry-based metabonomics coupled with multivariate data analysis was used to identify the plasma metabolites and metabolic pathways related to nephrotoxicity caused by intraperitoneal injection of low (50mg/kg) and high (100mg/kg) doses of acyclovir. Sixteen biomarkers were identified by metabonomics and nephrotoxicity results revealed the dose-dependent effect of acyclovir on kidney tissues. The present study showed that the top four metabolic pathways interrupted by acyclovir included the metabolisms of arachidonic acid, tryptophan, arginine and proline, and glycerophospholipid. This research proves the established metabonomic approach can provide information on changes in metabolites and metabolic pathways, which can be applied to in-depth research on the mechanism of acyclovir-induced kidney injury. PMID: 24863373 [PubMed - indexed for MEDLINE]