Laser Desorption Postionization Mass Spectrometry of Antibiotic-Treated Bacterial Biofilms Using Tunable Vacuum Ultraviolet Radiation

Gasper, Gerald L.; Takahashi, Lynelle K.; Zhou, Jia; Ahmed, Musahid; Moore, Jean K.; Hanley, Luke

doi:10.1021/ac101667q

Cited by 37 publications

(65 citation statements)

References 41 publications

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“…Overall, 10.5 eV photon energy displayed an optimal balance between sensitivity and fragmentation, in agreement with prior experiments. 26, 27, 35 Similar conclusions were reached from 7.87 – 10.5 eV synchrotron LDPI-MS of E. coli (tomato strain) monoculture blots (full mass spectra shown in Supplementary Information). The mass spectral peaks observed for E. coli and yeast monocultures were tabulated with the VUV photon energies at which they were first observed by synchrotron LDPI-MS (see Supplementary Information).…”

Section: Resultssupporting

confidence: 73%

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Differentiation of microbial species and strains in coculture biofilms by multivariate analysis of laser desorption postionization mass spectra

Bhardwaj

Cui

Hofstetter

et al. 2013

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7.87 to 10.5 eV vacuum ultraviolet (VUV) photon energies were used in laser desorption postionization mass spectrometry (LDPI-MS) to analyze biofilms comprised of binary cultures of interacting microorganisms. The effect of photon energy was examined using both tunable synchrotron and laser sources of VUV radiation. Principal components analysis (PCA) was applied to the MS data to differentiate species in Escherichia coli-Saccharomyces cerevisiae coculture biofilms. PCA of LDPI-MS also differentiated individual E. coli strains in a biofilm comprised of two interacting gene deletion strains, even though these strains differed from the wild type K-12 strain by no more than four gene deletions each out of approximately 2000 genes. PCA treatment of 7.87 eV LDPI-MS data separated the E. coli strains into three distinct groups, two “pure” groups, and a mixed region. Furthermore, the “pure” regions of the E. coli cocultures showed greater variance by PCA at 7.87 eV photon energies compared to 10.5 eV radiation. This is consistent with the expectation that the 7.87 eV photoionization selects a subset of low ionization energy analytes while 10.5 eV is more inclusive, detecting a wider range of analytes. These two VUV photon energies therefore give different spreads via PCA and their respective use in LDPI-MS constitute an additional experimental parameter to differentiate strains and species.

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Section: Resultssupporting

confidence: 73%

“…Prior synchrotron LDPI-MS studies 26, 27 led to the recent development of a refined laboratory VUV photoionization source that operates at 10.5 eV 25 to complement the 7.87 eV fluorine excimer laser source. 22 These two laboratory laser VUV sources were used to collect 7.87 and 10.5 eV laser LDPI-MS data from yeast and E. coli monocultures.…”

Section: Resultsmentioning

confidence: 99%

Differentiation of microbial species and strains in coculture biofilms by multivariate analysis of laser desorption postionization mass spectra

Bhardwaj

Cui

Hofstetter

et al. 2013

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“…8,20 A growth curve for E. faecalis colony biofilms (see Supporting Information) indicated growth for three days was sufficient to form a mature biofilm. The MPA-ampicillin spiked multilayers were sterilized by 20 min exposure to radiation from a germicidal ultraviolet lamp (254 nm, 4.8 watts, held ~30 cm from the sample, G15T8, Osram Sylvania, Danvers, MA).…”

Section: Methodsmentioning

confidence: 99%

Quantification of Antibiotic in Biofilm-Inhibiting Multilayers by 7.87 eV Laser Desorption Postionization MS Imaging

et al. 2012

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The potential of laser desorption postionization mass spectrometry (LDPI-MS) imaging for small molecule quantification is demonstrated here. The N-methylpiperazine acetamide of (MPA) ampicillin was adsorbed into polyelectrolyte multilayer surface coatings composed of chitosan and alginate, both high molecular weight biopolymers. These MPA-ampicillin spiked multilayers were then shown to inhibit the growth of E. faecalis biofilms that play a role in early stage infection of implanted medical devices. Finally, LDPI-MS imaging using 7.87 eV single photon ionization was found to detect MPA-ampicillin with the multilayers before and after biofilm growth with limits of quantification and detection of 0.6 and 0.3 nmoles, respectively. The capabilities of LDPI-MS imaging for small molecule quantification are compared to those of MALDI-MS. Furthermore, these results indicate that 7.87 eV LDPI-MS imaging should be applicable to quantification of a range of small molecular species on a variety of complex organic and biological surfaces. Finally, while MS imaging for quantification was demonstrated here using LDPI, it is a generally useful strategy that can be applied to other methods.

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“…Laser desorption mass spectrometry has previously been applied to detect fragments from medium range molecules, such as antibiotics, biofilms and peptides (Blaze et al, 2011;Gasper et al, 2010). The LPDI-MS instrument can detect single charge species up to 3000 Dalton.…”

Section: Greater Protein Size Does Not Lead To More Fragmentation Promentioning

confidence: 99%

Differential capacity of kaolinite and birnessite to protect surface associated proteins against thermal degradation

Chacon

García-Jaramillo

Liu

et al. 2018

Soil Biology and Biochemistry

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Soil organic carbon cycling depends on the presence and catalytic functionality of extracellular proteins. The mineral matrix has the capacity to enhance, maintain or impede this functionality through a variety of mechanisms. The goal of this research was to identify some of the mechanisms involved in determining the role of the mineral matrix towards proteins. To this end, we adsorbed Beta-Glucosidase (BG) and Bovine Serum Albumin (BSA) on the phyllosilicate kaolinite and the manganese oxide acid birnessite at pH 5 and pH 7. The protein-mineral samples were then subjected to gradual energy inputs equivalent to an intense forest fire using a laser and the abundance and molecular masses of desorbed organic compounds were recorded after ionization with tunable synchrotron ultravacuum vacuum ultraviolet radiation (VUV). We found that the mechanisms controlling the fate of proteins varied with mineralogy. Kaolinite adsorbed protein largely through hydrophobic interactions and produced negligible amounts of desorption fragments compared to birnessite, even at energy inputs equivalent to an intense forest fire. Acid birnessite adsorbed protein through coulombic forces at low energy levels, became a hydrolyzing catalyst at low energies and low pH and eventually turned into a reactant involving disintegration of both mineral and protein at higher energy inputs. Fragmentation of proteins was energy dependent, and did not occur below an energy threshold of 0.20 MW cm -2 . Neither signal abundance nor signal intensity were a function of protein size. Above the energy threshold value, BG adsorbed to birnessite at pH 7 showed an increase in signal abundance with increasing energy applications.. Signal intensities differed with adsorption pH for BSA but only at the highest energy level applied. Our results indicate that proteins adsorbed to kaolinite are likely to remain intact

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Laser Desorption Postionization Mass Spectrometry of Antibiotic-Treated Bacterial Biofilms Using Tunable Vacuum Ultraviolet Radiation

Cited by 37 publications

References 41 publications

Differentiation of microbial species and strains in coculture biofilms by multivariate analysis of laser desorption postionization mass spectra

Differentiation of microbial species and strains in coculture biofilms by multivariate analysis of laser desorption postionization mass spectra

Quantification of Antibiotic in Biofilm-Inhibiting Multilayers by 7.87 eV Laser Desorption Postionization MS Imaging

Differential capacity of kaolinite and birnessite to protect surface associated proteins against thermal degradation

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