Maleic anhydride proton sponge as a novel MALDI matrix for the visualization of small molecules (<250 m/z) in brain tumors by routine MALDI ToF imaging mass spectrometry

In the kidney, metabolic processes are different among the cortex (COR), outer medulla (OM), and inner medulla (IM). Using matrix-assisted laser desorption/ionization (MALDI) and imaging mass spectrometry (IMS), we examined the change of metabolites in the COR, OM, and IM of the rat kidney after furosemide treatment compared with vehicle-treated controls. Osmotic minipumps were implanted in male Sprague-Dawley rats to deliver 12 mg·day−1·rat−1 of furosemide. Vehicle-treated ( n = 14) and furosemide-treated (furosemide rats, n = 15) rats in metabolic cages received a fixed amount of rat chow (15 g·220 g body wt−1·day−1 for each rat) with free access to water intake for 6 days. At day 6, higher urine output (32 ± 4 vs. 9 ± 1 ml/day) and lower urine osmolality (546 ± 44 vs. 1,677 ± 104 mosmol/kgH2O) were observed in furosemide rats. Extracts of COR, OM, and IM were analyzed by ultraperformance liquid chromatography coupled with quadrupole time-of-flight (TOF) mass spectrometry, where multivariate analysis revealed significant differences between the two groups. Several metabolites, including acetylcarnitine, betaine, carnitine, choline, and glycerophosphorylcholine (GPC), were significantly changed. The changes of metabolites were further identified by MALDI-TOF/TOF and IMS. Their spatial distribution and relative quantitation in the kidneys were analyzed by IMS. Carnitine compounds were increased in COR and IM, whereas carnitine and acetylcarnitine were decreased in OM. Choline compounds were increased in COR and OM but decreased in IM from furosemide rats. Betaine and GPC were decreased in OM and IM. Taken together, MALDI-TOF/TOF and IMS successfully provide the spatial distribution and relative quantitation of metabolites in the kidney.

Download Full-text

Imaging Mass Spectrometry for Small Molecules

Mass Spectrometry Imaging in Food Analysis ◽

10.1201/9780429427879-3 ◽

2020 ◽

pp. 13-34

Author(s):

Fangbiao Li

Keyword(s):

Mass Spectrometry ◽

Small Molecules ◽

Imaging Mass Spectrometry

Download Full-text

Surface Plasmon Resonance Imaging-MALDI-TOF Imaging Mass Spectrometry of Thin Tissue Sections

Analytical Chemistry ◽

10.1021/acs.analchem.5b03309 ◽

2016 ◽

Vol 88 (4) ◽

pp. 2072-2079 ◽

Cited By ~ 9

Author(s):

Simon Forest ◽

Julien Breault-Turcot ◽

Pierre Chaurand ◽

Jean-Francois Masson

Keyword(s):

Mass Spectrometry ◽

Surface Plasmon Resonance ◽

Surface Plasmon ◽

Plasmon Resonance ◽

Imaging Mass Spectrometry ◽

Surface Plasmon Resonance Imaging ◽

Resonance Imaging ◽

Tissue Sections ◽

Maldi Tof

Download Full-text

N-doped graphene quantum dots as a novel highly-efficient matrix for the analysis of perfluoroalkyl sulfonates and other small molecules by MALDI-TOF MS

Analytical Methods ◽

10.1039/c7ay00112f ◽

2017 ◽

Vol 9 (13) ◽

pp. 2014-2020 ◽

Cited By ~ 10

Author(s):

Ziyu Rao ◽

Fanglan Geng ◽

Yiqi Zhou ◽

Dong Cao ◽

Yuehui Kang

Keyword(s):

Quantum Dots ◽

Small Molecules ◽

Small Molecule ◽

Graphene Quantum Dots ◽

Maldi Tof Ms ◽

Maldi Matrix ◽

Maldi Tof ◽

Doped Graphene ◽

Small Molecule Analysis ◽

Tof Ms

N-doped graphene quantum dots (N-GQDs) were sythesized by a facile method and applied as a MALDI matrix for small-molecule analysis.

Download Full-text

Discovery of a microbially produced small molecule in a host-specific organ

10.1101/2020.08.17.254854 ◽

2020 ◽

Author(s):

Katherine E. Zink ◽

Denise A. Tarnowski ◽

Phillip R. Lazzara ◽

Terry W. Moore ◽

Mark J. Mandel ◽

...

Keyword(s):

Mass Spectrometry ◽

Small Molecules ◽

Vibrio Fischeri ◽

Imaging Mass Spectrometry ◽

Light Organ ◽

Label Free ◽

Euprymna Scolopes ◽

Bacterial Luminescence ◽

Specific Organ ◽

Host Microbe Interactions

AbstractThe lifelong relationship between the Hawaiian bobtail squid, Euprymna scolopes, and its microbial symbiont, Vibrio fischeri, represents a simplified model system for studying microbiome establishment and maintenance. The bacteria colonize a dedicated symbiotic light organ in the squid, from which bacterial luminescence camouflages the hosts in a process termed counterillumination. The squid hosts hatch without their symbionts, which must be acquired from the ocean amid a diversity of non-beneficial bacteria, so precise molecular communication is required for initiation of the specific relationship. It is therefore likely that there may be specialized metabolites used in the light organ microenvironment to modulate these processes. To identify small molecules that may influence the establishment of this symbiosis, we used imaging mass spectrometry to analyze metabolite production in V. fischeri with altered biofilm production, which correlates directly to colonization capability in its host. ‘Biofilm-Up’ and ‘Biofilm-Down’ mutants were compared to a wild-type strain, and masses that were more abundantly produced by the biofilm-up mutant were detected. Using a combination of structure elucidation and synthetic chemistry, one such signal was determined to be a diketopiperazine, cyclo(d-histidyl-l-proline). This diketopiperazine modulated luminescence in V. fischeri and, using label-free imaging mass spectrometry, was directly detected in the light organ of the colonized host. This work highlights the continued need for untargeted discovery efforts in host-microbe interactions and showcases the benefits of the squid-Vibrio system for identification and characterization of small molecules that modulate microbiome behaviors.Significance StatementThe complexity of animal microbiomes presents challenges to defining signaling molecules within the microbial consortium and between the microbes and the host. By focusing on the binary symbiosis between Vibrio fischeri and Euprymna scolopes, we have combined genetic analysis with direct imaging to define and study small molecules in the intact symbiosis. We have detected and characterized a diketopiperazine produced by strong biofilm-forming V. fischeri strains that was detectable in the host symbiotic organ, and which influences bacterial luminescence. Biofilm formation and luminescence are critical for initiation and maintenance of the association, respectively, suggesting that the compound may link early and later development stages, providing further evidence that multiple small molecules are important in establishing these beneficial relationships.

Download Full-text