Campus Units

Chemistry, Genetics, Development and Cell Biology, Biochemistry, Biophysics and Molecular Biology, Ames Laboratory, Center for Metabolic Biology

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

3-2015

Journal or Book Title

Analytical and Bioanalytical Chemistry

Volume

407

Issue

8

First Page

2301

Last Page

2309

DOI

10.1007/s00216-015-8460-5

Abstract

A significant limiting factor in achieving high spatial resolution for matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) imaging is the size of the laser spot at the sample surface. Here, we present modifications to the beam-delivery optics of a commercial MALDI-linear ion trap-Orbitrap instrument, incorporating an external Nd:YAG laser, beam-shaping optics, and an aspheric focusing lens, to reduce the minimum laser spot size from ~50 μm for the commercial configuration down to ~9 μm for the modified configuration. This improved system was applied for MALDI-MS imaging of cross sections of juvenile maize leaves at 5-μm spatial resolution using an oversampling method. A variety of different metabolites including amino acids, glycerolipids, and defense-related compounds were imaged at a spatial resolution well below the size of a single cell. Such images provide unprecedented insights into the metabolism associated with the different tissue types of the maize leaf, which is known to asymmetrically distribute the reactions of C4 photosynthesis among the mesophyll and bundle sheath cell types. The metabolite ion images correlate with the optical images that reveal the structures of the different tissues, and previously known and newly revealed asymmetric metabolic features are observed.

Comments

This is a manuscript of an article from Analytical and Bioanalytical Chemistry 407 (2015): 2301, doi: 10.1007/s00216-015-8460-5. The final publication is available at Springer via http://dx.doi.o rg/10.1007/s00216-015-8460-5.

Copyright Owner

Springer-Verlag

Language

en

File Format

application/pdf

Published Version

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