@article{jeffries_gomez_macdonald_gamcsik_2022, title={Direct Detection of Glutathione Biosynthesis, Conjugation, Depletion and Recovery in Intact Hepatoma Cells}, volume={23}, ISSN={["1422-0067"]}, DOI={10.3390/ijms23094733}, abstractNote={Nuclear magnetic resonance (NMR) spectroscopy was used to monitor glutathione metabolism in alginate-encapsulated JM-1 hepatoma cells perfused with growth media containing [3,3′-13C2]-cystine. After 20 h of perfusion with labeled medium, the 13C NMR spectrum is dominated by the signal from the 13C-labeled glutathione. Once 13C-labeled, the high intensity of the glutathione resonance allows the acquisition of subsequent spectra in 1.2 min intervals. At this temporal resolution, the detailed kinetics of glutathione metabolism can be monitored as the thiol alkylating agent monobromobimane (mBBr) is added to the perfusate. The addition of a bolus dose of mBBr results in rapid diminution of the resonance for 13C-labeled glutathione due to a loss of this metabolite through alkylation by mBBr. As the glutathione resonance decreases, a new resonance due to the production of intracellular glutathione-bimane conjugate is detectable. After clearance of the mBBr dose from the cells, intracellular glutathione repletion is then observed by a restoration of the 13C-glutathione signal along with wash-out of the conjugate. These data demonstrate that standard NMR techniques can directly monitor intracellular processes such as glutathione depletion with a time resolution of approximately < 2 min.}, number={9}, journal={INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES}, author={Jeffries, Rex E. and Gomez, Shawn M. and Macdonald, Jeffrey M. and Gamcsik, Michael P.}, year={2022}, month={May} }
 @article{niemuth_harms_macdonald_stoskopf_2018, title={Propylene Glycol in Free-Ranging Green Sea Turtle Plasma}, volume={9}, ISSN={1944-687X 1944-687X}, url={http://dx.doi.org/10.3996/122017-JFWM-099}, DOI={10.3996/122017-JFWM-099}, abstractNote={Abstract
               Metabolomics is the study of metabolites, the small-molecular-weight end products of metabolism. Propylene glycol is a synthetic diol commonly used as antifreeze, as a humectant, and in the production of polyester compounds. In otherwise healthy animals, propylene glycol has generally been considered a contaminant, iatrogenic, or unexplained. We demonstrate the presence of propylene glycol in plasma of free-ranging apparently healthy green sea turtles Chelonia mydas and individuals impacted by cold stun syndrome, without iatrogenic administration or known sample processing contamination, using one- and two-dimensional proton nuclear magnetic resonance spectroscopy techniques. There was not a statistically significant difference in relative propylene glycol concentration between the two cohorts (two-sided random sampling two-sample permutation test, P = 0.842, R = 1,000). The presence of this metabolite raises important questions about sea turtle physiology and potential latent environmental contamination and serves as a starting point for future characterization of lipid metabolism and glycolysis in green sea turtles.}, number={2}, journal={Journal of Fish and Wildlife Management}, publisher={U.S. Fish and Wildlife Service}, author={Niemuth, Jennifer N. and Harms, Craig A. and Macdonald, Jeffrey M. and Stoskopf, Michael K.}, year={2018}, month={Dec}, pages={617–623} }
 @article{tech_tikunov_farooq_morrissy_meidinger_fish_green_liu_li_mungall_et al._2017, title={Pyruvate Kinase Inhibits Proliferation during Postnatal Cerebellar Neurogenesis and Suppresses Medulloblastoma Formation}, volume={77}, ISSN={["1538-7445"]}, DOI={10.1158/0008-5472.can-16-3304}, abstractNote={Abstract
               Aerobic glycolysis supports proliferation through unresolved mechanisms. We have previously shown that aerobic glycolysis is required for the regulated proliferation of cerebellar granule neuron progenitors (CGNP) and for the growth of CGNP-derived medulloblastoma. Blocking the initiation of glycolysis via deletion of hexokinase-2 (Hk2) disrupts CGNP proliferation and restricts medulloblastoma growth. Here, we assessed whether disrupting pyruvate kinase-M (Pkm), an enzyme that acts in the terminal steps of glycolysis, would alter CGNP metabolism, proliferation, and tumorigenesis. We observed a dichotomous pattern of PKM expression, in which postmitotic neurons throughout the brain expressed the constitutively active PKM1 isoform, while neural progenitors and medulloblastomas exclusively expressed the less active PKM2. Isoform-specific Pkm2 deletion in CGNPs blocked all Pkm expression. Pkm2-deleted CGNPs showed reduced lactate production and increased SHH-driven proliferation. 13C-flux analysis showed that Pkm2 deletion reduced the flow of glucose carbons into lactate and glutamate without markedly increasing glucose-to-ribose flux. Pkm2 deletion accelerated tumor formation in medulloblastoma-prone ND2:SmoA1 mice, indicating the disrupting PKM releases CGNPs from a tumor-suppressive effect. These findings show that distal and proximal disruptions of glycolysis have opposite effects on proliferation, and that efforts to block the oncogenic effect of aerobic glycolysis must target reactions upstream of PKM. Cancer Res; 77(12); 3217–30. ©2017 AACR.}, number={12}, journal={CANCER RESEARCH}, author={Tech, Katherine and Tikunov, Andrey P. and Farooq, Hamza and Morrissy, A. Sorana and Meidinger, Jessica and Fish, Taylor and Green, Sarah C. and Liu, Hedi and Li, Yisu and Mungall, Andrew J. and et al.}, year={2017}, month={Jun}, pages={3217–3230} }
 @article{thelwall_simpson_rabbani_clark_pourdeyhimi_macdonald_blackband_gamcsik_2012, title={In vivo MR studies of glycine and glutathione metabolism in a rat mammary tumor}, volume={25}, ISSN={["0952-3480"]}, DOI={10.1002/nbm.1745}, abstractNote={The metabolism of glycine into glutathione was monitored noninvasively in vivo in intact rat mammary adenocarcinomas (R3230Ac) by MRI and MRS. Metabolism was tracked by following the isotope label from intravenously infused [2‐13C]‐glycine into the glycinyl residue of glutathione. Signals from [2‐13C]‐glycine and γ‐glutamylcysteinyl‐[2‐13C]‐glycine (13C‐glutathione) were detected by nonlocalized 13C spectroscopy, as these resonances are distinct from background signals. In addition, using spectroscopic imaging methods, heterogeneity in the in vivo tumor distribution of glutathione was observed. In vivo spectroscopy also detected isotope incorporation from [2‐13C]‐glycine into both the 2‐ and 3‐carbons of serine. Analyses of tumor tissue extracts showed single‐ and multiple‐label incorporation from [2‐13C]‐glycine into serine from metabolism through the serine hydroxymethyltransferase and glycine cleavage system pathways. Mass spectrometric analysis of extracts also showed that isotope‐labeled serine is further metabolized via the trans‐sulfuration pathway, as 13C isotope labels appear in both the glycinyl and cysteinyl residues of glutathione. Our studies demonstrate the use of MRI and MRS for the monitoring of tumor metabolic processes central to oxidative stress defense. Copyright © 2011 John Wiley & Sons, Ltd.}, number={2}, journal={NMR IN BIOMEDICINE}, author={Thelwall, Peter E. and Simpson, Nicholas E. and Rabbani, Zahid N. and Clark, M. Daniel and Pourdeyhimi, Roxana and Macdonald, Jeffrey M. and Blackband, Stephen J. and Gamcsik, Michael P.}, year={2012}, month={Feb}, pages={271–278} }
 @article{grahl_puttikamonkul_macdonald_gamcsik_ngo_hohl_cramer_2011, title={In vivo hypoxia and a fungal alcohol dehydrogenase influence the pathogenesis of invasive pulmonary aspergillosis}, volume={7}, number={7}, journal={PLoS Pathogens}, author={Grahl, N. and Puttikamonkul, S. and Macdonald, J. M. and Gamcsik, M. P. and Ngo, L. Y. and Hohl, T. M. and Cramer, R. A.}, year={2011} }