Vladimír Havlíček

Palacký University of Olomouc, Olmütz, Olomoucký, Czech Republic

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Publications (151)325.16 Total impact

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    ABSTRACT: We report an MS-based workflow for identification of phosphorylated peptides from trypsinized protein mixtures and cell lysates that is suitable for high-throughput sample analysis. The workflow is based on an in situ enrichment on matrix-assisted laser desorption/ionization (MALDI) plates that were functionalized by TiO2 using automated ion landing apparatus that can operate unsupervised. The MALDI plate can be functionalized by TiO2 into any array of predefined geometry (here, 96 positions for samples and 24 for mass calibration standards) made compatible with a standard MALDI spotter and coupled with high-performance liquid chromatography. The in situ MALDI plate enrichment was compared with a standard precolumn-based separation and achieved comparable or better results than the standard method. The performance of this new workflow was demonstrated on a model mixture of proteins as well as on Jurkat cells lysates. The method showed improved signal-to-noise ratio in a single MS spectrum, which resulted in better identification by MS/MS and a subsequent database search. Using the workflow, we also found specific phosphorylations in Jurkat cells that were nonspecifically activated by phorbol 12-myristate 13-acetate. These phosphorylations concerned the mitogen-activated protein kinase/extracellular signal-regulated kinase signaling pathway and its targets and were in agreement with the current knowledge of this signaling cascade. Control sample of non-activated cells was devoid of these phosphorylations. Overall, the presented analytical workflow is able to detect dynamic phosphorylation events in minimally processed mammalian cells while using only a short high-performance liquid chromatography gradient. Copyright © 2015 John Wiley & Sons, Ltd.
    Journal of Mass Spectrometry 06/2015; 50(6). DOI:10.1002/jms.3586 · 2.71 Impact Factor
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    ABSTRACT: Hyaluronic acid is a naturally occurring linear polysaccharide with substantial medical potential. In this work, discrimination of tyramine-based hyaluronan derivatives was accessed by ion mobility–mass spectrometry of deprotonated molecules and nuclear magnetic resonance spectroscopy. As the product ion mass spectra did not allow for direct isomer discrimination in mixture, the reductive labeling of oligosaccharides as well as stable isotope labeling was performed. The ion mobility separation of parent ions together with the characteristic fragmentation for reduced isomers providing unique product ions allowed us to identify isomers present in a mixture and determine their mutual isomeric ratio. The determination used simple recalculation of arrival time distribution areas of unique ions to areas of deprotonated molecules. Mass spectrometry data were confirmed by nuclear magnetic resonance spectroscopy. Copyright © 2015 John Wiley & Sons, Ltd.
    Journal of Mass Spectrometry 06/2015; 50(6). DOI:10.1002/jms.3596 · 2.71 Impact Factor
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    ABSTRACT: Siderophores play important roles in microbial iron piracy, and are applied as infectious disease biomarkers and novel pharmaceutical drugs. Inductively coupled plasma and molecular mass spectrometry (ICP-MS) combined with high resolution separations allow characterization of siderophores in complex samples taking advantages of mass defect data filtering, tandem mass spectrometry, and iron-containing compound quantitation. The enrichment approaches used in siderophore analysis and current ICP-MS technologies are reviewed. The recent tools for fast dereplication of secondary metabolites and their databases are reported. This review on siderophores is concluded with their recent medical, biochemical, geochemical, and agricultural applications in mass spectrometry context. © 2015 Wiley Periodicals, Inc. Mass Spec Rev. © 2015 Wiley Periodicals, Inc.
    Mass Spectrometry Reviews 05/2015; DOI:10.1002/mas.21461 · 8.05 Impact Factor
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    ABSTRACT: Fabry disease is an X-linked lysosomal storage disease due to deficient α-galactosidase A (α-Gal A) activity and the resultant lysosomal accumulation of globotriaosylceramide (Gb3) and related lipids primarily in blood vessels, kidney, heart, and other organs. The renal distribution of stored glycolipid species in the α-Gal A knockout mouse model was compared to that in mice to assess relative distribution and absolute amounts of accumulated sphingolipid isoforms. Twenty isoforms of five sphingolipid groups were visualized by mass spectrometry imaging (MSI), and their distribution was compared with immunohistochemical (IHC) staining of Gb3, the major stored glycosphingolipid in consecutive tissue sections. Quantitative bulk lipid analysis of tissue sections was assessed by electrospray ionization with tandem mass spectrometry (ESI-MS/MS). In contrast to the findings in wild-type mice, all three analytical techniques (MSI, IHC, and ESI-MS/MS) revealed increases in Gb3 isoforms and ceramide dihexosides (composed mostly of galabiosylceramides), respectively. To our knowledge, this is the first report of the distribution of individual molecular species of Gb3 and galabiosylceramides in kidney sections in Fabry disease mouse. In addition, the spatial distribution of ceramides, ceramide monohexosides, and sphingomyelin forms in renal tissue is presented and discussed in the context of their biosynthesis.
    Analytical and Bioanalytical Chemistry 12/2014; 407(8). DOI:10.1007/s00216-014-8402-7 · 3.58 Impact Factor
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    ABSTRACT: Matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI MSI) is a well-established analytical technique for determining spatial localization of lipids in biological samples. The use of Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometers for the molecular imaging of endogenous compounds is gaining popularity, since the high mass accuracy and high mass resolving power enables accurate determination of exact masses and, consequently, a more confident identification of these molecules. The high mass resolution FT-ICR imaging datasets are typically large in size. In order to analyze them in an appropriate timeframe, the following approach has been employed: the FT-ICR imaging datasets were spatially segmented by clustering all spectra by their similarity. The resulted spatial segmentation maps were compared with the histologic annotation. This approach facilitates interpretation of the full datasets by providing spatial regions of interest. The application of this approach, which has originally been developed for MALDI-TOF MSI datasets, to the lipidomic analysis of head and neck tumor tissue revealed new insights into the metabolic organization of the carcinoma tissue.
    Journal of the American Society for Mass Spectrometry 11/2014; 26(1). DOI:10.1007/s13361-014-1018-5 · 3.19 Impact Factor
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    ABSTRACT: Nanostructure-assisted laser desorption/ionization (NALDI) has been recognized as a powerful matrix-free mass spectrometry tool ideal for imaging of small molecules. In this report, the NALDI approach was compared with matrix-assisted laser desorption/ionization (MALDI) mass spectrometry in terms of sensitivity, reproducibility, and lateral resolution, which can be achieved in mass spectrometry imaging (MSI) experiments using a Nd:YAG laser. Scanning electron microscopy was used for surface topology analysis and evaluation of a putative surface-enhanced sensitivity effect, which was observed upon reduction of the laser focus. NALDI was identified as a more reproducible technique lacking MSI artifacts arising from distant tissue removal known from MALDI oversampling.
    Analytical and Bioanalytical Chemistry 11/2014; 407(8). DOI:10.1007/s00216-014-8294-6 · 3.58 Impact Factor
  • Biochemical and Biophysical Research Communications 10/2014; 453(3):680. · 2.28 Impact Factor
  • Journal of Mass Spectrometry 08/2014; 49(8). DOI:10.1002/jms.3383 · 2.71 Impact Factor
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    ABSTRACT: A new analytical protocol for identification of Prussian blue (PB) and indigo was proposed. Pigments useful for dating of artworks were detected by flow injection analysis/electrospray ionization mass spectrometry after alkalization of their suspensions in water, decomposition of PB to iron (III) hydroxide and hexacyanoferrate (II) and reduction of indigo to soluble leucoindigo using sodium dithionite. Limits of detection (PB 47 pg, indigo 59 pg) complied with requirements for analysis of microsamples of historical paintings. Potential of the developed method was proven in analysis of blue samples of two oil paintings from the 20(th) century. Further, PB was confirmed in a microsample from a painting of 'Crucifixion', St. Sebestian church on St. Hill in Mikulov, Czech Republic. Copyright © 2013 John Wiley & Sons, Ltd.
    Journal of Mass Spectrometry 08/2013; 48(8):927-30. DOI:10.1002/jms.3228 · 2.71 Impact Factor
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    ABSTRACT: We have developed a de novo sequencing software tool (CYCLONE) and applied it for determination of cyclic peptides. The program uses a non-redundant database of 312 nonribosomal building blocks identified to date in bacteria and fungi (more than 230 additional residues in the database list were isobaric). The software was used to fully characterize the tandem mass spectrum of several cyclic peptides and provide sequence tags. The general strategy of the script was based on fragment ion pre-characterization to accomplish unambiguous b-ion series assignments. Showcase examples were a cyclic tetradepsipeptide beauverolide, a cyclic hexadepsipeptide roseotoxin A, a lasso-like hexapeptide pseudacyclin A, and a cyclic undecapeptide cyclosporin A. The extent of ion scrambling in smaller peptides was as low as 5 % of total ion current; this demonstrated the feasibility of CYCLONE de novo sequencing. The robustness of the script was also tested against database sets of various sizes and isotope-containing data. It can be downloaded from the http://ms.biomed.cas.cz/MSTools/ website. Figure ᅟ
    Journal of the American Society for Mass Spectrometry 05/2013; 24(8). DOI:10.1007/s13361-013-0652-7 · 3.19 Impact Factor
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    ABSTRACT: Due to their low polarities and dielectric constants, analytes in solvents such as hexane, chloroform, and ethyl acetate exhibit poor electrospray ionization (ESI) efficiency. These are deemed to be "non-ESI-friendly" solvents. Continuous flow extractive desorption electrospray ionization (CF-EDESI) is a novel ambient ionization technique that was recently developed in our group to manipulate protein charge distributions. Here we demonstrate its potential for ionizing analytes from non-ESI-friendly solvents. This feature makes CF-EDESI attractive to the general analytical community due to its apparent potential in lipidomics, normal phase separations, and hyphenation of mass spectrometry with HPLC-NMR systems. In this context, interest was subsequently initiated to discern mechanistic aspects of CF-EDESI. To achieve this, mechanistic experiments associated with a seemingly similar ambient ionization technique, extractive electrospray ionization (EESI), were emulated to compare CF-EDESI and EESI. Analysis of a series of fatty acids in multiple solvents in the negative ionization mode revealed differences between the two techniques. Whereas EESI has been previously shown to operate via extraction of analytes into the spray solvent, data presented here for CF-EDESI point toward a liquid-liquid mixing process to facilitate ionization. Further, a partial factorial design experiment was performed to evaluate the effects of different experimental variables on signal intensity. Sample flow rate was confirmed to be among the most significant factors to affect sensitivity. As a whole, the work presented provides greater insight into a new ambient ionization process, which exhibits expanded capabilities over conventional ESI; in this case, for direct analysis from non-ESI-friendly solvents.
    Analytica chimica acta 03/2013; 769:84-90. DOI:10.1016/j.aca.2013.01.018 · 4.52 Impact Factor
  • Vladimir Havlicek, Karel Lemr, Kevin Albert Schug
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    ABSTRACT: Recently, a major increase in mass spectrometer installations has occurred in routine clinical microbiology laboratories worldwide. At present, there are hundreds of various instruments sold and the market is still far from being saturated. Although the clinical community still declares it has discovered a "new technology", the first mass spectrometry investigation of whole microorganism analysis was published in 1970, and the first commercial protein mass-fingerprinting package was introduced in 2000. This critical review covers the microbiology literature related to mass spectrometry published primarily in the 2011-2012 period. It also reports on mass spectrometry vendor sales, pending patent applications and company plans for the near future.
    Analytical Chemistry 11/2012; 85(2). DOI:10.1021/ac3031866 · 5.83 Impact Factor
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    ABSTRACT: Atmospheric pressure chemical ionization is known for producing unusual artifacts of the ionization process in some cases. In this work, processes occuring in atmospheric pressure chemical ionization/MS of orotic acid that afforded ions accompanying protonated and deprotonated orotic acid molecules in the spectra were studied. Two processes ran in parallel in the ion source: decarboxylation of neutral orotic acid and collision-induced dissociation of its protonated or deprotonated form. A procedure discerning pre-ionization decomposition and post-ionization dissociation by manipulating ion source parameters was proposed. Experiments with isotopically labeled solvents confirmed ion-molecule reactions of the product of collision-induced dissociation of protonated orotic acid with solvent molecules in the ion source and even under vacuum in the ion trap.
    Journal of Mass Spectrometry 06/2012; 47(6):720-6. DOI:10.1002/jms.3006 · 2.71 Impact Factor
  • The Journal of Antibiotics 02/2012; 65(4):219-21. DOI:10.1038/ja.2012.2 · 2.04 Impact Factor
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    ABSTRACT: The potential of mMass software search tool with new compound libraries was demonstrated on metabolomics of Scedosporium prolificans, S. apiospermum and Pseudallescheria boydii sensu stricto. Cyclic peptides pseudacyclins, small molecular weight tyroscherin analogues and various lipids were annotated by public software tool (http://www.mmass.org) utilising accurate matrix-assisted laser desorption/ionisation mass spectral data of intact fungal spores. Electrospray ionisation combined with tandem mass spectrometry was used for monohexosylceramide characterisation in fungal extracts.
    Mycoses 10/2011; 54 Suppl 3:37-42. DOI:10.1111/j.1439-0507.2011.02109.x · 1.81 Impact Factor
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    ABSTRACT: This work reports on a new and extremely simple approach for determination of a double bond position by a laser desorption ionization mass spectrometry. It is solely based on the catalytic properties of nanostructured surfaces used in nanoassisted laser desorption ionization experiments. These surfaces can induce oxidation of analytes, which results in a mass shift that can be detected by mass spectrometry. If a site of unsaturation is oxidized and cleaved, the m/z difference is diagnostic of the position of a double bond. By demonstrating that the oxidation depends on the analyte surface dwell time, it was proven that it is caused by the surface activity and not by the laser desorption ionization process itself. Control matrix-assisted laser desorption/ionization (MALDI) experiment showed only a limited partial oxidation and no time dependency of the process. The ability to determine a position of a double bond was demonstrated on polyunsaturated phospholipids and cyclosporine A. In some other cases, however, the unexpected oxidation could cause confusion, as demonstrated for a glycosphingolipid from a porcine brain extract.
    Analytical Chemistry 06/2011; 83(14):5661-5. DOI:10.1021/ac200801t · 5.83 Impact Factor
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    ABSTRACT: Traditional tissue-sectioning techniques for histological samples utilize various embedding media to stabilize the tissue on a sectioning target and to provide a smooth cutting surface. Due to the ion suppression effect in MALDI ionization and number of background peaks in the low-mass region, these media are not suitable for mass spectrometry imaging (MSI) experiments. To overcome this, droplets of water are often used to mount the tissue on a sectioning target, but the ice block formed around the tissue does not provide a good support for sectioning of fragile samples. In this work, we propose a novel embedding media, compatible with MALDI ionization and MSI experiments, based on poly[N-(2-hydroxypropyl)methacrylamide] (pHPMA). Using a reversible addition-fragmentation chain transfer polymerization technique, well-defined pHPMA polymer with narrow mass distribution was prepared. Benefits of the resulted pHPMA-based embedding media were tested on different tissue samples.
    Analytical Chemistry 06/2011; 83(13):5458-62. DOI:10.1021/ac2011679 · 5.83 Impact Factor
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    ABSTRACT: Knowledge of the spatial distribution of lipids in the intraocular lens is important for understanding the physiology and biochemistry of this unique tissue and for gaining a better insight into the mechanisms underlying diseases of the lens. Following our previous study showing the spatial distribution of sphingolipids in the porcine lens, the current study used ultra performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOFMS) to provide the whole lipidome of porcine lens and these studies were supplemented by matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI MSI) of the lens using ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) to determine the spatial distribution of glycerophospholipids. Altogether 172 lipid species were identified with high confidence and their concentration was determined. Sphingomyelins, phosphatidylcholines, and phosphatidylethanolamines were the most abundant lipid classes. We then determined the spatial and concentration-dependent distributions of 20 phosphatidylcholines, 6 phosphatidylethanolamines, and 4 phosphatidic acids. Based on the planar molecular images of the lipids, we report the organization of fiber cell membranes within the ocular lens and suggest roles for these lipids in normal and diseased lenses.
    PLoS ONE 04/2011; 6(4):e19441. DOI:10.1371/journal.pone.0019441 · 3.53 Impact Factor
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    ABSTRACT: Scanning electron microscopy was used to investigate rivulets that are formed on the analyzed surface during desorption electrospray ionization (DESI) experiment. Ferromagnetic nanoparticles added to the spray solvent in a form of colloid solution functioned as an additional surface probe. The existence of the rivulets was confirmed on glass and newly demonstrated on two different types of porous polytetrafluoroethylene (PTFE). The results show that in standard DESI set-up the rivulets are arranged into very regular shapes. Same rivulets were obtained in DESI experiments without high voltage on the sprayer. However, no such rivulets or any other regular patterns were found on a surface in nano-DESI (nanospray DESI without the carrier nebulizing gas) experiments. This indicates that symmetrical rivulets are created by the hydrodynamical rather than electrostatic forces. It was also demonstrated that blocking the rivulets by a simple physical barrier did not influence known surface charging effects.
    Journal of Mass Spectrometry 03/2011; 46(3):256-61. DOI:10.1002/jms.1888 · 2.71 Impact Factor

Publication Stats

1k Citations
325.16 Total Impact Points

Institutions

  • 2008–2015
    • Palacký University of Olomouc
      • Department of Analytical Chemistry
      Olmütz, Olomoucký, Czech Republic
  • 1993–2015
    • Academy of Sciences of the Czech Republic
      • • Laboratory of Biotransformation
      • • Laboratory of Molecular Structure Characterization
      • • Institute of Hydrobiology
      Praha, Praha, Czech Republic
  • 1996–2014
    • The Police Academy of the Czech Republic in Prague
      Praha, Praha, Czech Republic
  • 1996–2010
    • Institute of Chemical Technology Prague
      • • Department of Organic Chemistry
      • • Department of Chemistry of Solid State
      Praha, Praha, Czech Republic
  • 2002
    • Charles University in Prague
      • Faculty of Science
      Praha, Praha, Czech Republic
  • 2001
    • University of Washington Seattle
      • Department of Medicinal Chemistry
      Seattle, Washington, United States