Vladimír Havlíček

Palacký University of Olomouc, Olmütz, Olomoucký, Czech Republic

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Publications (142)249.35 Total impact

  • Biological Mass Spectrometry 08/2014; 49(8). · 3.41 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.
    Biological Mass Spectrometry 08/2013; 48(8):927-30. · 3.41 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; · 3.59 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. · 4.31 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; · 5.70 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.
    Biological Mass Spectrometry 06/2012; 47(6):720-6. · 3.41 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. · 1.28 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. · 5.70 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. · 5.70 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.
    Biological Mass Spectrometry 03/2011; 46(3):256-61. · 3.41 Impact Factor
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    ABSTRACT: O-Glycosylation is a ubiquitous eukaryotic post-translational modification, whereas early reports of S-linked glycopeptides have never been verified. Prokaryotes also glycosylate proteins, but there are no confirmed examples of sidechain glycosylation in ribosomal antimicrobial polypeptides collectively known as bacteriocins. Here we show that glycocin F, a bacteriocin secreted by Lactobacillus plantarum KW30, is modified by an N-acetylglucosamine β-O-linked to Ser18, and an N-acetylhexosamine S-linked to C-terminal Cys43. The O-linked N-acetylglucosamine is essential for bacteriostatic activity, and the C-terminus is required for full potency (IC(50) 2 nM). Genomic context analysis identified diverse putative glycopeptide bacteriocins in Firmicutes. One of these, the reputed lantibiotic sublancin, was shown to contain a hexose S-linked to Cys22.
    FEBS letters 02/2011; 585(4):645-50. · 3.54 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 01/2011; 6(4):e19441. · 3.73 Impact Factor
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    Jaroslav Pól, Martin Strohalm, Vladimír Havlíček, Michael Volný
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    ABSTRACT: This review describes the current state of mass spectrometry imaging (MSI) in life sciences. A brief overview of mass spectrometry principles is presented followed by a thorough introduction to the MSI workflows, principles and areas of application. Three major desorption-ionization techniques used in MSI, namely, secondary ion mass spectrometry (SIMS), matrix-assisted laser desorption ionization (MALDI), and desorption electrospray ionization (DESI) are described, and biomedical and life science imaging applications of each ionization technique are reviewed. A separate section is devoted to data handling and current challenges and future perspectives are briefly discussed at the end.
    Histochemie 10/2010; 134(5):423-43. · 2.61 Impact Factor
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    ABSTRACT: Pseudallescheria boydii sensu lato is an emerging fungal pathogen causing fatal infections in both immunocompromised and immunocompetent hosts. In this work, two P. boydii isolates (human and animal origin) have been identified as being producers of cyclic peptides. Five putative nonribosomal peptides with a unique structure, which have been named pseudacyclins, were characterized by nuclear magnetic resonance spectroscopy and mass spectrometry. The most abundant representative of the pseudacyclins was quantified also on fungal spores. The presence of these peptides on inhaled fungal spores creates the possibility for exploitation of pseudacyclins as early indicators of fungal infections caused by Pseudallescheria species.
    Journal of Natural Products 06/2010; 73(6):1027-32. · 3.29 Impact Factor
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    ABSTRACT: Mass spectrometry imaging of tissue-lipid transfers without MALDI matrix is demonstrated. Commercially available nanostructured surfaces (nano-assisted laser desorption-ionization or NALDI) are used as substrates for imprinting of tissue sections. The lithographic transfers are then washed and the two-dimensional distribution of the lipids is imaged by laser desorption-ionization mass spectrometry. The NALDI imaging of lipid transfers is compared with standard MALDI imaging of matrix-coated tissue sections. The obtained images are of the same quality, and no spatial information is lost due to the imprinting process. NALDI imaging is faster due to the absence of the time-consuming matrix deposition step, and the NALDI mass spectra are less complex and easier to interpret than standard MALDI. In this particular application example, NALDI mass spectrometry is able to identify the same lipid species as MALDI mass spectrometry and provides better distinction between kidney and adrenal gland tissues based on the lipid analysis.
    Analytical Chemistry 06/2010; 82(12):4994-7. · 5.70 Impact Factor
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    ABSTRACT: Detergents are frequently used for protein isolation and solubilization. Their presence is crucial in membrane protein protocols or in lipid raft proteomics. However, they are usually poorly compatible with mass spectrometry. Several different sample preparation protocols are routinely used, but they are either laborious or suffer from sample losses. Here, we describe our alternative method for nonionic detergent removal. It is based on selective detergent extraction after capture of the sample on a reversed phase cartridge. The extraction is performed by chlorinated solvents and works well for polyoxyethylene based nonionic detergents, but also for polymers like polyethylene and propylene glycol. Detergent removal can be also carried out on the protein level but a special care must be taken with hydrophobic proteins. In such cases, it is preferable to perform detergent removal after proteolysis which digests the protein to peptides and reduces the hydrophobicity. The method can easily be automated and is compatible with hydrogen/deuterium exchange coupled to mass spectrometry.
    Analytical Chemistry 06/2010; 82(12):5107-16. · 5.70 Impact Factor
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    ABSTRACT: a Katedra analytické chemie, Přírodovědecká fakulta, Uni-verzita Palackého v Olomouci, tř. 17. listopadu 12, 771 46 Olomouc, b Mikrobiologický ústav Akademie věd ČR, Ví-deňská 1083, 142 20 Praha 4 martin.svidrnoch@volny.cz Úvod Výzkum v oblasti chemických věd a forenzního zkou-mání je velmi rozsáhlý, neustále jsou vyvíjeny nové a efektivnější postupy s využitím moderních instrumentál-ních metod jak identifikovat a stanovovat jednotlivé analy-ty v rozmanitém spektru vzorků a matric. Jednou ze základních metod ve forenzní analýze je i hmotnostní spektrometrie (MS) 1 . Pro uvedené účely je zapotřetřebí použít takovou metodu, která poskytne rychlé a ekonomicky dostupné analýzy s co nejnižšími detekční-mi limity. Chceme-li provádět rychlou analýzu in situ, lze s výhodou použít některou z desorpčních ionizačních tech-nik. Ionizace desorpcí elektrosprejem (DESI) eliminuje úpravu vzorku a zjednodušuje samotnou analýzu. Účelem této práce je poskytnout metodu rychlého screeningu pro průkaz intoxikace biologicky aktivní látkou v krevní stopě s využitím DESI/MS. Experimentální část Veškerá měření byla provedena na hmotnostním spektrometru s iontovou pastí (LCQ, Thermo Finnigan, San Jose, USA), kde jako iontový zdroj sloužila modifiko-vaná sprejovací část desorpčního nano-elektrospreje s kovem pokrytou sprejovací kapilárou (PicoTip emitter GlassTip, ID = 2 ± 1 m; New Objectiv, Woburn, USA) 2 . Kapilára byla předem naplněna sprejovací kapalinou sestávající ze směsi acetonitrilu a vody v poměru 9:1 (v/v), modifikované kyselinou mravenčí (30 l/2 ml směsi) a následně na ni bylo vloženo sprejovací napětí v rozsahu +1,5 až +3,5 kV. Jako modelové látky byly použity kofein, efedrin (Sigma Aldrich, Praha) a nikotin (Merck, Praha). Uvedené modelové látky byly předem změřeny bez pří-tomnosti matrice a byla získána hmotnostní (MS) a frag-mentační (MS/MS) spektra, která sloužila k identifikaci zkoumaných látek v krevní matrici. Poté byly postupně naneseny na vzorkovací povrch samotná krevní matrice a krev obsahující známou koncentraci uvedených látek. Obr. 1. Hmotnostní spektrum plné krve s obsahem kofeinu 10 mg l -1 (M r 195), nanesené na filtr ze skelných mikrovláken
    Chemicke Listy 06/2010; · 0.45 Impact Factor
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    ABSTRACT: While tools for the automated analysis of MS and LC-MS/MS data are continuously improving, it is still often the case that at the end of an experiment, the mass spectrometrist will spend time carefully examining individual spectra. Current software support is mostly provided only by the instrument vendors, and the available software tools are often instrument-dependent. Here we present a new generation of mMass, a cross-platform environment for the precise analysis of individual mass spectra. The software covers a wide range of processing tasks such as import from various data formats, smoothing, baseline correction, peak picking, deisotoping, charge determination, and recalibration. Functions presented in the earlier versions such as in silico digestion and fragmentation were redesigned and improved. In addition to Mascot, an interface for ProFound has been implemented. A specific tool is available for isotopic pattern modeling to enable precise data validation. The largest available lipid database (from the LIPID MAPS Consortium) has been incorporated and together with the new compound search tool lipids can be rapidly identified. In addition, the user can define custom libraries of compounds and use them analogously. The new version of mMass is based on a stand-alone Python library, which provides the basic functionality for data processing and interpretation. This library can serve as a good starting point for other developers in their projects. Binary distributions of mMass, its source code, a detailed user's guide, and video tutorials are freely available from www.mmass.org .
    Analytical Chemistry 06/2010; 82(11):4648-51. · 5.70 Impact Factor
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    ABSTRACT: The intraocular lens contains high levels of both cholesterol and sphingolipids, which are believed to be functionally important for normal lens physiology. The aim of this study was to explore the spatial distribution of sphingolipids in the ocular lens using mass spectrometry imaging (MSI). Matrix-assisted laser desorption/ionization (MALDI) imaging with ultra high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to visualize the lipid spatial distribution. Equatorially-cryosectioned, 12 microm thick slices of tissue were thaw-mounted to an indium-tin oxide (ITO) glass slide by soft-landing to an ethanol layer. This procedure maintained the tissue integrity. After the automated MALDI matrix deposition, the entire lens section was examined by MALDI MSI in a 150 microm raster. We obtained spatial- and concentration-dependent distributions of seven lens sphingomyelins (SM) and two ceramide-1-phosphates (CerP), which are important lipid second messengers. Glycosylated sphingolipids or sphingolipid breakdown products were not observed. Owing to ultra high resolution MS, all lipids were identified with high confidence, and distinct distribution patterns for each of them are presented. The distribution patterns of SMs provide an understanding of the physiological functioning of these lipids in clear lenses and offer a novel pathophysiological means for understanding diseases of the lens.
    The Journal of Lipid Research 04/2010; 51(8):2295-302. · 4.39 Impact Factor
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    ABSTRACT: Nostotrebin 6, a new polyphenolic compound with a fully substituted 2,2'-bis(cyclopent-4-en-1,3-dione) skeleton, was isolated from a methanolic extract of the cyanobacterial strain Nostoc sp. str. Lukesová 27/97. The structure of this compound was determined using X-ray crystallography and further supported by NMR, IR spectroscopy, and MS. Nostotrebin 6 is an S-parabolic I-parabolic noncompetitive inhibitor of acetylcholinesterase (IC(50) = 5.5 microM) and an S-parabolic I-parabolic mixed inhibitor of butyrylcholinesterase (IC(50) = 6.1-7.5 microM). The inhibitory potency of nostotrebin 6 was compared with that of tacrine and galanthamine.
    Journal of Enzyme Inhibition and Medicinal Chemistry 03/2010; 25(3):414-20. · 1.50 Impact Factor

Publication Stats

753 Citations
249.35 Total Impact Points

Institutions

  • 2008–2014
    • Palacký University of Olomouc
      • • Department of Analytical Chemistry
      • • Regional Centre of Advanced Technologies and Materials
      Olmütz, Olomoucký, Czech Republic
    • Semmelweis University
      Budapeŝto, Budapest, Hungary
  • 1993–2013
    • Academy of Sciences of the Czech Republic
      • • Ústav organické chemie a biochemie
      • • Hydrobiologický ústav
      • • Laboratoř biotransformací
      Praha, Praha, Czech Republic
  • 1994–2010
    • Institute of Chemical Technology Prague
      • Department of Organic Chemistry
      Praha, Praha, Czech Republic
  • 2006
    • Státní Veterinární Ústav Praha
      Praha, Praha, Czech Republic
  • 1997–2002
    • Charles University in Prague
      • • Katedra analytické chemie (PF)
      • • Katedra biochemie
      Praha, Hlavni mesto Praha, Czech Republic
  • 2001
    • University of Washington Seattle
      • Department of Medicinal Chemistry
      Seattle, WA, United States