Browsing by Author "Franco, Lauren C."

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Autonomous metabolomics for rapid metabolite identification in global profiling
(2015-01) Benton, H. Paul; Ivanisevic, Julijana; Mahieu, N. G.; Kurczy, M. E.; Johnson, Caroline H.; Franco, Lauren C.; Rinehart, Duane; Valentine, E.; Gowda, H.; Ubhi, B. K.; Tautenhahn, R.; Gieschen, A.; Fields, Matthew W.; Patti, G. J.; Siuzdak, Gary
An autonomous metabolomic workflow combining mass spectrometry analysis with tandem mass spectrometry data acquisition was designed to allow for simultaneous data processing and metabolite characterization. Although previously tandem mass spectrometry data have been generated on the fly, the experiments described herein combine this technology with the bioinformatic resources of XCMS and METLIN. As a result of this unique integration, we can analyze large profiling datasets and simultaneously obtain structural identifications. Validation of the workflow on bacterial samples allowed the profiling on the order of a thousand metabolite features with simultaneous tandem mass spectra data acquisition. The tandem mass spectrometry data acquisition enabled automatic search and matching against the METLIN tandem mass spectrometry database, shortening the current workflow from days to hours. Overall, the autonomous approach to untargeted metabolomics provides an efficient means of metabolomic profiling, and will ultimately allow the more rapid integration of comparative analyses, metabolite identification, and data analysis at a systems biology level.
Comprehensive bioimaging with fluorinated nanoparticles using breathable liquids
(2015-01) Kurczy, M. E.; Zhu, Zheng-Jiang; Ivanisevic, Julijana; Schuyler, A. M.; Lalwani, K.; Santidrian, A. F.; David, J. M.; Giddabasappa, A.; Roberts, A. J.; Olivos, H. J.; O'Brien, P. J.; Franco, Lauren C.; Fields, Matthew W.; Paris, L. P.; Friedlander, M.; Johnson, Caroline H.; Epstein, A. A.; Gendelman, H. E.; Wood, Malcolm R.; Felding, B. H.; Patti, G. J.; Spiker, M. E.; Siuzdak, Gary
Fluorocarbons are lipophobic and non-polar molecules that exhibit remarkable biocompatibility, with applications in liquid ventilation and synthetic blood. The unique properties of these compounds have also enabled mass spectrometry imaging of tissues where the fluorocarbons act as a Teflon-like coating for nanostructured surfaces to assist in desorption/ionization. Here we report fluorinated ?gold nanoparticles (f-AuNPs) designed to facilitate nanostructure imaging mass spectrometry. Irradiation of f-AuNPs results in the release of the fluorocarbon ligands providing a driving force for analyte desorption. The f-AuNPs allow for the mass spectrometry analysis of both lipophilic and polar (central carbon) metabolites. An important property of AuNPs is that they also act as contrast agents for X-ray microtomography and electron microscopy, a feature we have exploited by infusing f-AuNPs into tissue via fluorocarbon liquids to facilitate multimodal (molecular and anatomical) imaging.
Cr(VI) reduction and physiological toxicity are impacted by resource ratio in Desulfovibrio vulgaris
(2018-03) Franco, Lauren C.; Steinbeisser, Sadie; Zane, Grant M.; Wall, Judy D.; Fields, Matthew W.
Desulfovibrio spp. are capable of heavy metal reduction and are well-studied systems for understanding metal fate and transport in anaerobic environments. Desulfovibrio vulgaris Hildenborough was grown under environmentally relevant conditions (i.e., temperature, nutrient limitation) to elucidate the impacts on Cr(VI) reduction on cellular physiology. Growth at 20 °C was slower than 30 °C and the presence of 50 μM Cr(VI) caused extended lag times for all conditions, but once growth resumed the growth rate was similar to that without Cr(VI). Cr(VI) reduction rates were greatly diminished at 20 °C for both 50 and 100 μM Cr(VI), particularly for the electron acceptor limited (EAL) condition in which Cr(VI) reduction was much slower, the growth lag much longer (200 h), and viability decreased compared to balanced (BAL) and electron donor limited (EDL) conditions. When sulfate levels were increased in the presence of Cr(VI), cellular responses improved via a shorter lag time to growth. Similar results were observed between the different resource (donor/acceptor) ratio conditions when the sulfate levels were normalized (10 mM), and these results indicated that resource ratio (donor/acceptor) impacted D. vulgaris response to Cr(VI) and not merely sulfate limitation. The results suggest that temperature and resource ratios greatly impacted the extent of Cr(VI) toxicity, Cr(VI) reduction, and the subsequent cellular health via Cr(VI) influx and overall metabolic rate. The results also emphasized the need to perform experiments at lower temperatures with nutrient limitation to make accurate predictions of heavy metal reduction rates as well as physiological states in the environment.