Direct Analysis of Triterpenes from High-Salt Fermented Cucumbers Using Infrared Matrix-Assisted Laser Desorption Electrospray Ionization (IR-MALDESI)

Ekelöf, Måns; McMurtrie, Erin K.; Nazari, Milad; Johanningsmeier, Suzanne D.; Muddiman, David C.

doi:10.1007/s13361-016-1541-7

Cited by 29 publications

(21 citation statements)

References 38 publications

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“…216 Lipids also have the potential to show tumor boundaries, specifically in breast cancer. 217 Because of their diverse structure, several common ionization sources, including MALDI, 1,20,42,97 DESI, 22,217,218 SIMS, 219–221 and IR-MALDESI, 18,19 have found success in lipid imaging. Notably, newly developed laser spray ionization (LSI), with its simple sample preparation, is becoming more commonly used for lipids as well.…”

Section: Biological Applicationsmentioning

confidence: 99%

“…3,91,236 Furthermore, the use of plants as an alternative research system is commonplace so, naturally, researchers have also transitioned to imaging plant-based samples. 234,242 In the last 2 years, food products, such as onions, 243 cucumbers, 18 and citrus peel extracts, 237 have been analyzed, but it is clear that theoretically any item can be imaged with the appropriate equipment. 244,245 For example, DESI-MSI was utilized to understand the thin-layer chromatography (TLC) separation of the citrus peel extracts directly on the TLC plates (Figure 8).…”

Section: Biological Applicationsmentioning

confidence: 99%

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Mass Spectrometry Imaging: A Review of Emerging Advancements and Future Insights

et al. 2017

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Section: Biological Applicationsmentioning

confidence: 99%

Section: Biological Applicationsmentioning

confidence: 99%

Mass Spectrometry Imaging: A Review of Emerging Advancements and Future Insights

et al. 2017

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“…Recently IR‐MALDESI has been applied to plant tissues, which have many different inherent sampling challenges from mammalian tissues . IR‐MALDESI has proved to be a highly effective method for the analysis of a diverse range of plant tissues . Each of these experiments answered specific fundamental biological questions.…”

Section: Introductionmentioning

confidence: 99%

“…18 IR-MALDESI has proved to be a highly effective method for the analysis of a diverse range of plant tissues. [19][20][21] Each of these experiments answered specific fundamental biological questions. Naturally, quantification is the next step towards providing plant metabolite analysis with the analytical rigor applied to other sample types.…”

Section: Introductionmentioning

confidence: 99%

Development of a relative quantification method for infrared matrix‐assisted laser desorption electrospray ionization mass spectrometry imaging of Arabidopsis seedlings

Bagley

Stepanova

Ekelöf

et al. 2020

Rapid Comm Mass Spectrometry

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Rationale Mass spectrometry imaging of young seedlings is an invaluable tool in understanding how mutations affect metabolite accumulation in plant development. However, due to numerous biological considerations, established methods for the relative quantification of analytes using infrared matrix‐assisted laser desorption electrospray ionization (IR‐MALDESI) mass spectrometry imaging are not viable options. In this study, we report a method for the quantification of auxin‐related compounds using stable‐isotope‐labelled (SIL) indole‐3‐acetic acid (IAA) doped into agarose substrate. Methods Wild‐type Arabidopsis thaliana seedlings, sur2 and wei8 tar2 loss‐of‐function mutants, and YUC1 gain‐of‐function line were grown for 3 days in the dark in standard growth medium. SIL‐IAA was doped into a 1% low‐melting‐point agarose gel and seedlings were gently laid on top for IR‐MALDESI imaging with Orbitrap mass spectrometry analysis. Relative quantification was performed post‐acquisition by normalization of auxin‐related compounds to SIL‐IAA in the agarose. Amounts of auxin‐related compounds were compared between genotypes to distinguish the effects of the mutations on the accumulation of indolic metabolites of interest. Results IAA added to agarose was found to remain stable, with repeatability and abundance features of IAA comparable with those of other compounds used in other methods for relative quantification in IR‐MALDESI analyses. Indole‐3‐acetaldoxime was increased in sur2 mutants compared with wild‐type and other mutants. Other auxin‐related metabolites were either below the limits of quantification or successfully quantified but showing little difference among mutants. Conclusions Agarose was shown to be an appropriate sampling surface for IR‐MALDESI mass spectrometry imaging of Arabidopsis seedlings. SIL‐IAA doping of agarose was demonstrated as a viable technique for relative quantification of metabolites in live seedlings or tissues with similar biological considerations.

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“…Since most HTS experiments are performed in a semi‐targeted manner, the total analysis time can be reduced by performing the experiments at lower resolving powers. Furthermore, the ESI post‐ionization in IR‐MALDESI allows for direct analysis of analytes from matrices containing high salt and protein concentrations, that are used to perform enzymatic reactions …”

Section: Introductionmentioning

confidence: 99%

Direct screening of enzyme activity using infrared matrix‐assisted laser desorption electrospray ionization

Nazari

Ekelöf

Khodjaniyazova

et al. 2017

Rapid Comm Mass Spectrometry

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Rationale High-throughput screening (HTS) is a critical step in the drug discovery process. However, most mass spectrometry-based HTS methods require sample cleanup steps prior to analysis. In this work we present the utility of infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) for monitoring an enzymatic reaction directly from a biological buffer system with no sample cleanup and at high throughput. Methods IR-MALDESI was used to directly analyze reaction mixtures from a well plate at different time points after reaction initiation. The percent conversion of precursors to products was used to screen the enzyme activity. The reaction was performed with two different concentrations of precursors and enzyme in order to assess the dynamic range of the assay. Eventually, a pseudo-HTS study was designed to investigate the utility of IR-MALDESI screening enzyme activity in a high-throughput manner. Results IR-MALDESI was able to readily monitor the activity of IDH1 over time at two different concentrations of precursors and enzyme. The calculated Z-factors of 0.65 and 0.41 confirmed the suitability of the developed method for screening enzyme activity in HTS manner. Finally, in a single-blind pseudo-HTS analysis IR-MALDESI was able to correctly predict the identity of all samples, where 8/10 samples were identified with high confidence and the other 2 samples with lower confidence. Conclusions The enzymatic activity of IDH1 was screened by directly analyzing the reaction content from the buffer in well plates with no sample cleanup steps. This proof-of-concept study demonstrates the robustness of IR-MALDESI for direct analysis of enzymatic reactions from biological buffers with no sample cleanup and its immense potential for HTS applications.

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Direct Analysis of Triterpenes from High-Salt Fermented Cucumbers Using Infrared Matrix-Assisted Laser Desorption Electrospray Ionization (IR-MALDESI)

Cited by 29 publications

References 38 publications

Mass Spectrometry Imaging: A Review of Emerging Advancements and Future Insights

Mass Spectrometry Imaging: A Review of Emerging Advancements and Future Insights

Development of a relative quantification method for infrared matrix‐assisted laser desorption electrospray ionization mass spectrometry imaging of Arabidopsis seedlings

Direct screening of enzyme activity using infrared matrix‐assisted laser desorption electrospray ionization

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