02436nas a2200241 4500008004100000022001400041245011500055210006900170260011000239300001400349490000600363520149000369100002701859700001701886700002101903700002001924700002101944700002501965700002101990700002302011700003102034856012902065 2014 eng d a1759-966000aMatrix-assisted laser desorption/ionization mass spectrometry analysis of dimethyl arginine isomers from urine0 aMatrixassisted laser desorptionionization mass spectrometry anal aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcAPR a4602-46090 v63 a

Isomeric asymmetric and symmetric dimethyl arginine (ADMA and SDMA respectively) residues are excreted in urine and are putative markers of cardiovascular and chronic kidney diseases. In this work, we demonstrate simultaneous and quantitative detection of endogeneous ADMA and SDMA from urine samples of healthy subjects using MALDI-TOF MS without any chromatographic separation. The DMA isomers yielded [M + H](+) ions along with their product ions formed due to MALDI in-source fragmentation. The precursor ions were validated using MALDI-TOF MS/MS as well as direct injection ESI-Q-TOF MS/MS. ADMA and SDMA generated unique product ions at similar to m/z 46 and similar to m/z 172 respectively in the MS-mode itself. These were advantageously used for full scan-mode absolute quantification of the isomeric metabolites. The m/z observed for all the ions was within 10 ppm mass accuracy. The calibration method was established by generating internal standard normalized peak area-based concentration response curves using synthetic standards. Good linearities (R-2 > 0.95) with acceptable intra-assay, inter-assay variation (within 15% RSD) and excellent recoveries were observed for quality control samples. Finally, endogeneous concentrations of the metabolites were determined in urine from healthy subjects (n = 11). ADMA and SDMA were found to be in the range of 1.6-8 mu M and 2.9-9.1 mu M in urine and were in agreement with previously reported physiological levels.

1 aBhattacharya, Nivedita1 aSingh, Ajeet1 aGhanate, Avinash1 aPhadke, Gayatri1 aParmar, Dharmesh1 aDhaware, Deepika, G.1 aBasak, Trayambak1 aSengupta, Shantanu1 aPanchagnula, Venkateswarlu uhttps://library.ncl.res.in/content/matrix-assisted-laser-desorptionionization-mass-spectrometry-analysis-dimethyl-arginine-002451nas a2200193 4500008004100000245025800041210006900299260000800368490000700376520146600383653013101849100002501980700002602005700002702031700002502058700003102083700002102114856012202135 2017 eng d00aScalable metabolite supplementation strategy against antibiotic resistant pathogen Chromobacterium violaceum induced by NAD(+)/NADH(+) imbalanceA scalable metabolite supplementation strategy against antibiotic resistant pathogen Chromobacterium violaceu0 aScalable metabolite supplementation strategy against antibiotic  cAPR0 v113 a

BACKGROUND: The leading edge of the global problem of antibiotic resistance necessitates novel therapeutic strategies. This study develops a novel systems biology driven approach for killing antibiotic resistant pathogens using benign metabolites. RESULTS: Controlled laboratory evolutions established chloramphenicol and streptomycin resistant pathogens of Chromobacterium. These resistant pathogens showed higher growth rates and required higher lethal doses of antibiotic. Growth and viability testing identified malate, maleate, succinate, pyruvate and oxoadipate as resensitising agents for antibiotic therapy. Resistant genes were catalogued through whole genome sequencing. Intracellular metabolomic profiling identified violacein as a potential biomarker for resistance. The temporal variance of metabolites captured the linearized dynamics around the steady state and correlated to growth rate. A constraints-based flux balance model of the core metabolism was used to predict the metabolic basis of antibiotic susceptibility and resistance. CONCLUSIONS: The model predicts electron imbalance and skewed NAD/NADH ratios as a result of antibiotics - chloramphenicol and streptomycin. The resistant pathogen rewired its metabolic networks to compensate for disruption of redox homeostasis. We foresee the utility of such scalable workflows in identifying metabolites for clinical isolates as inevitable solutions to mitigate antibiotic resistance.

10aAntibiotic resistance; Flux balance analysis; Flux variability analysis; Metabolism; Metabolomic; NAD; NADH; Redox homeostasis1 aBanerjee, Deepanwita1 aParmar, Dharmeshkumar1 aBhattacharya, Nivedita1 aGhanate, Avinash, D.1 aPanchagnula, Venkateswarlu1 aRaghunathan, Anu uhttps://library.ncl.res.in/content/scalable-metabolite-supplementation-strategy-against-antibiotic-resistant-pathogen02464nas a2200301 4500008004100000022001400041245009900055210006900154260000800223300000900231490000700240520142600247100002601673700002701699700002201726700002301748700002601771700002101797700002701818700002301845700004101868700002201909700002301931700002301954700002701977700003102004856012702035 2020 eng d a2045-232200aPlausible diagnostic value of urinary isomeric dimethylarginine ratio for diabetic nephropathy0 aPlausible diagnostic value of urinary isomeric dimethylarginine  cFEB a29700 v103 a

Altered circulatory asymmetric and symmetric dimethylarginines have been independently reported in patients with end-stage renal failure suggesting their potential role as mediators and early biomarkers of nephropathy. These alterations can also be reflected in urine. Herein, we aimed to evaluate urinary asymmetric to symmetric dimethylarginine ratio (ASR) for early prediction of diabetic nephropathy (DN). In this cross-sectional study, individuals with impaired glucose tolerance (IGT), newly diagnosed diabetes (NDD), diabetic microalbuminuria (MIC), macroalbuminuria (MAC), and normal glucose tolerance (NGT) were recruited from Dr. Mohans' Diabetes Specialties centre, India. Urinary ASR was measured using a validated high-throughput MALDI-MS/MS method. Significantly lower ASR was observed in MIC (0.909) and MAC (0.741) in comparison to the NGT and NDD groups. On regression models, ASR was associated with MIC [OR: 0.256; 95% CI: 0.158-0.491] and MAC [OR 0.146; 95% CI: 0.071-0.292] controlled for all the available confounding factors. ROC analysis revealed ASR cut-point of 0.95 had C-statistic of 0.691 (95% CI: 0.627-0.755) to discriminate MIC from NDD with 72% sensitivity. Whereas, an ASR cut-point of 0.82 had C-statistic of 0.846 (95% CI: 0.800 - 0.893) had 91% sensitivity for identifying MAC. Our results suggest ASR as a potential early diagnostic biomarker for DN among the Asian Indians.

1 aParmar, Dharmeshkumar1 aBhattacharya, Nivedita1 aKannan, Shanthini1 aVadivel, Sangeetha1 aPandey, Gautam, Kumar1 aGhanate, Avinash1 aRagi, Nagarjuna, Chary1 aPrabu, Paramasivam1 aPramodkumar, Thyparambil, Aravindaks1 aManickam, Nagaraj1 aMohan, Viswanathan1 aSripadi, Prabhakar1 aKuppan, Gokulakrishnan1 aPanchagnula, Venkateswarlu uhttps://library.ncl.res.in/content/plausible-diagnostic-value-urinary-isomeric-dimethylarginine-ratio-diabetic-nephropathy