26
|
Rončević I, Bastien G, Cvačka J, Kaleta J, Michl J. CB11H10– and Related Carborenes. Inorg Chem 2020; 59:12453-12460. [DOI: 10.1021/acs.inorgchem.0c01557] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
27
|
Nekvasilová P, Kulik N, Rychlá N, Pelantová H, Petrásková L, Bosáková Z, Cvačka J, Slámová K, Křen V, Bojarová P. How Site‐Directed Mutagenesis Boosted Selectivity of a Promiscuous Enzyme. Adv Synth Catal 2020. [DOI: 10.1002/adsc.202000604] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
28
|
Strmeň T, Vrkoslav V, Bosáková Z, Cvačka J. Atmospheric pressure chemical ionization mass spectrometry at low flow rates: Importance of ion source housing. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34:e8722. [PMID: 31912928 DOI: 10.1002/rcm.8722] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 12/01/2019] [Accepted: 01/06/2020] [Indexed: 06/10/2023]
Abstract
RATIONALE Hyphenation of atmospheric pressure chemical ionization (APCI) mass spectrometry with capillary and micro high-performance liquid chromatography (HPLC) is attractive for many applications, but reliable ion sources dedicated to these conditions are still missing. There are a number of aspects to consider when designing such an ion source, including the susceptibility of the ionization processes to ambient conditions. Here we discuss the importance of ion source housing for APCI at low flow rates. METHODS Selected compounds dissolved in various solvents were used to study ionization reactions at 10 μL/min flow rate. APCI spectra were generated using the Ion Max-S source (Thermo Fisher Scientific) operated with or without the ion source housing. RESULTS The APCI spectra of most compounds measured in the open and enclosed ion sources were markedly different. The differences were explained by water and oxygen molecules that entered the plasma region of the open ion source. Water tended to suppress charge transfer processes while oxygen diminished electron capture reactions and prevented the formation of acetonitrile-related radical cations useful for localizing double bonds in lipids. The effects associated with the ion source housing were significantly less important for compounds that are easy to protonate or deprotonate. CONCLUSIONS The use of ion source housing prevented alternative ionization channels leading to unwanted or unexpected ions. Compared with the conventional flow rate mode (1 mL/min), the effects of ambient air components were significantly higher at 10 μL/min, emphasizing the need for ion source housing in APCI sources dedicated to low flow rates.
Collapse
|
29
|
Strnad Š, PraŽienková V, Holubová M, Sýkora D, Cvačka J, Maletínská L, Železná B, Kuneš J, Vrkoslav V. Mass spectrometry imaging of free-floating brain sections detects pathological lipid distribution in a mouse model of Alzheimer's-like pathology. Analyst 2020; 145:4595-4605. [PMID: 32436545 DOI: 10.1039/d0an00592d] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Mass spectrometry imaging (MSI) is a modern analytical technique capable of monitoring the spatial distribution of compounds within target tissues. Collection and storage are important steps in sample preparation. The recommended and most widely used preservation procedure for MSI is freezing samples in isopentane and storing them at temperatures below -80 °C. On the other hand, the most common and general method for preserving biological samples in clinical practice is fixation in paraformaldehyde. Special types of samples prepared from these fixed tissues that are used for histology and immunohistochemistry are free-floating sections. It would be very beneficial if the latter procedure could also be applicable for the samples intended for subsequent MSI analysis. In the present work, we optimized and evaluated paraformaldehyde-fixed free-floating sections for the analysis of lipids in mouse brains and used the sections for the study of lipid changes in double transgenic APP/PS1 mice, a model of Alzheimer's-like pathology. Moreover, we examined the neuroprotective properties of palm11-PrRP31, an anorexigenic and glucose-lowering analog of prolactin-releasing peptide, and liraglutide, a type 2 diabetes drug. From the free-floating sections, we obtained lipid images without interference or delocalization, and we demonstrated that free-floating sections can be used for the MSI of lipids. In the APP/PS1 mice, we observed a changed distribution of various lipids compared to the controls. The most significant changes in lipids in the brains of APP/PS1 mice compared to wild-type controls were related to gangliosides (GM2 36:1, GM3 36:1) and phosphatidylinositols (PI 38:4, 36:4) in regions where the accumulation of senile plaques occurred. In APP/PS1 mice peripherally treated with palm11-PrRP31 or liraglutide for 2 months, we found that both peptides reduced the amount and space occupied by lipids, which were linked to the senile plaques. These results indicate that palm11-PrRP31 as well as liraglutide might be potentially useful in the treatment of neurodegenerative diseases.
Collapse
|
30
|
Vrkoslav V, Rumlová B, Strmeň T, Cvačka J. Temperature-programmed capillary high-performance liquid chromatography with atmospheric pressure chemical ionization mass spectrometry for analysis of fatty acid methyl esters. J Sep Sci 2020; 43:2579-2588. [PMID: 32277790 DOI: 10.1002/jssc.201901235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 04/07/2020] [Accepted: 04/07/2020] [Indexed: 11/10/2022]
Abstract
A new capillary high-performance liquid chromatography method with atmospheric pressure chemical ionization mass spectrometry was developed for the analysis of fatty acid methyl esters and long-chain alcohols. The chromatographic separation was achieved using a Zorbax SB-C18 HPLC column (0.3 × 150 mm, 3.5 μm) with a mobile phase composed of acetonitrile and formic acid and delivered isocratically at a flow rate of 10 μL/min. The column temperature was programmed simply, using a common column oven. Good reproducibility of the temperature profile and retention times were achieved. The temperature programming during the isocratic high-performance liquid chromatography run had a similar effect as a solvent gradient; it reduced retention times of later eluting analytes and improved their detection limits. Two atmospheric pressure chemical ionization sources of the mass spectrometry detector were compared: an enclosed conventional ion source and an in-house made ion source with a glass microchip nebulizer. The enclosed source provided better detectability of saturated fatty acid methyl esters and made it possible to determine the double bond positions using acetonitrile-related adducts, while the open chip-based source provided better analytical figures of merit for unsaturated fatty acid methyl esters. Temperature-programmed capillary high-performance liquid chromatography is a promising method for analyzing neutral lipids in lipidomics and other applications.
Collapse
|
31
|
Bould J, Clegg W, Waddell PG, Cvačka J, Dušek M, Londesborough MGS. A Reversible NO-Triggered Multiple Metallaborane Cluster Fusion by Ligand Expulsion/Addition from (PMe 2Ph) 4Pt 2B 10H 10 to Afford (PMe 2Ph) 8Pt 8B 40H 40 and (PMe 2Ph) 5Pt 4B 20H 20. Inorg Chem 2020; 59:5030-5040. [PMID: 32207620 DOI: 10.1021/acs.inorgchem.0c00247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The dimetallic boron hydride cluster, (PMe2Ph)4Pt2B10H10 (1-Pt2), is known to reversibly sequester small molecules (e.g., O2, CO, and SO2) across its Pt-Pt cluster vector. Here, we report the very different effect of the addition of nitric oxide (NO) to solutions of (1-Pt2) that prompts the elimination of some of its phosphine ligands and the autofusion of the resultant {(PMe2Ph)xPt2B10H10} units to afford the metallaborane conglomerates (PMe2Ph)8Pt8B40H40 (2-Pt8, 38%) and (PMe2Ph)5Pt4B20H20 (3-Pt4, 34%). Single-crystal X-ray studies of these multicluster assemblies reveal the links between the clusters to be a combination of both Pt-Pt bonds and Pt-μH-B 2-electron, 3-center bonds in (2-Pt8) and Pt-μH-B 2-electron, 3-center bonds in (3-Pt4). For compound (2-Pt8), the cluster assemblage can be effectively reversed by the addition of ethyl isonitrile (EtNC) to afford (EtNC)3(PMe2Ph)2Pt2B10H10 4 in quantitative yield. The compounds were characterized by mass spectrometry, multielement NMR spectroscopy, and single-crystal X-ray diffraction studies.
Collapse
|
32
|
Hudeček O, Benoni R, Reyes-Gutierrez PE, Culka M, Šanderová H, Hubálek M, Rulíšek L, Cvačka J, Krásný L, Cahová H. Dinucleoside polyphosphates act as 5'-RNA caps in bacteria. Nat Commun 2020; 11:1052. [PMID: 32103016 PMCID: PMC7044304 DOI: 10.1038/s41467-020-14896-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 02/07/2020] [Indexed: 12/12/2022] Open
Abstract
It has been more than 50 years since the discovery of dinucleoside polyphosphates (NpnNs) and yet their roles and mechanisms of action remain unclear. Here, we show that both methylated and non-methylated NpnNs serve as RNA caps in Escherichia coli. NpnNs are excellent substrates for T7 and E. coli RNA polymerases (RNAPs) and efficiently initiate transcription. We demonstrate, that the E. coli enzymes RNA 5′-pyrophosphohydrolase (RppH) and bis(5′-nucleosyl)-tetraphosphatase (ApaH) are able to remove the NpnN-caps from RNA. ApaH is able to cleave all NpnN-caps, while RppH is unable to cleave the methylated forms suggesting that the methylation adds an additional layer to RNA stability regulation. Our work introduces a different perspective on the chemical structure of RNA in prokaryotes and on the role of RNA caps. We bring evidence that small molecules, such as NpnNs are incorporated into RNA and may thus influence the cellular metabolism and RNA turnover. Nicotinamide adenine dinucleotide and coenzyme A serve as a 5′-cap of prokaryotic RNA. Here the authors report that methylated and non-methylated dinucleoside polyphosphates (NpnNs) exist as Escherichia coli RNA caps which can be cleaved by 5′-pyrophosphohydrolase (RppH) and bis(5′-nucleosyl)-tetraphosphatase (ApaH).
Collapse
|
33
|
Akkol EK, Šmejkal K, Kurtul E, Ilhan M, Güragac FT, İşcan GS, Acıkara ÖB, Cvačka J, Buděšínský M. Inhibitory activity of Scorzonera latifolia and its components on enzymes connected with healing process. JOURNAL OF ETHNOPHARMACOLOGY 2019; 245:112168. [PMID: 31430525 DOI: 10.1016/j.jep.2019.112168] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 06/28/2019] [Accepted: 08/14/2019] [Indexed: 06/10/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Scorzonera latifolia (Fisch. & Mey.) DC. (Asteraceae) grows naturally in Eastern Anatolia, northeastern Iran, and Caucasus. Latex of S. latifolia roots is used in Turkish folk medicine for its analgesic effects, externally to cure infertility in women, and internally as an antihelmintic. The milk obtained from the stem of the Scorzonera species is used for wound healing activity. Antinociceptive, anti-inflammatory, wound-healing, antioxidant, and antimicrobial activities have previously been reported for S. latifolia. AIM OF THE STUDY A methanol extract of the aerial parts of Scorzonera latifolia that had been shown to possess wound-healing activity, was used to elucidate the possible mechanism of the wound-healing activity and to identify the compound(s) responsible for the effect by means of bioassay-guided fractionation. MATERIALS AND METHODS The wound-healing activity potential of methanol extract of S. latifolia was detected by evaluating the inhibitory activity on the collagenase, hyaluronidase and elastase, which play important roles in the wound-healing process. Succesive fractionation of the methanol extract using petroleum ether, chloroform, ethyl acetate, respectively, and the residual wateryielded four respective fractions. The ethyl acetate part, which was determined as the most active fraction, was selected for further separation using chromatographic techniques. RESULTS Ethylacetate fraction exhibited significant inhibitory activities on collagenase and elastase. Chromatographic separation of the ethylacetate extract yielded an active subfraction, from which was used to isolate quercetin-3-O-β-apiofuranosyl-(1'''→2'')-β-D-glucopyranoside (1), quercetin-3-O-α-rhamnopyranosyl-(1→6)-β-D-galactopyranoside (2), isoorientin (3), and 7-methylisoorientin (4). Of the compounds tested, 7-methylisoorientin (4) exerted inhibitory activity on collagenase and elastase, while quercetin-3-O-β-apiofuranosyl-(1'''→2'')-β-glucopyranoside (1) inhibited collagenase only. None of the fractions, or isolated compounds showed any inhibitory effect on hyaluronidase. It must be mentioned, that in vitro tests showed that compounds 1-4 inhibit the collagenase and elastase and could help wound-healing process. However, the inhibititory effect of the methanol extract appears to be greater than that of both of the ethylacetate fraction, subfraction G and the isolated compounds, which suggest that a synergistic interaction of several compounds could be responsible for the wound-healing activity of the aerial parts of S. latifolia.
Collapse
|
34
|
Poad BLJ, Marshall DL, Harazim E, Gupta R, Narreddula VR, Young RSE, Duchoslav E, Campbell JL, Broadbent JA, Cvačka J, Mitchell TW, Blanksby SJ. Combining Charge-Switch Derivatization with Ozone-Induced Dissociation for Fatty Acid Analysis. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:2135-2143. [PMID: 31347025 DOI: 10.1007/s13361-019-02285-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 07/07/2019] [Accepted: 07/08/2019] [Indexed: 06/10/2023]
Abstract
The specific positions of carbon-carbon double bond(s) within an unsaturated fatty acid exert a significant effect on the physical and chemical properties of the lipid that ultimately inform its biological function(s). Contemporary liquid chromatography-mass spectrometry (MS) strategies based on electrospray ionization coupled to tandem MS can easily detect fatty acyl lipids but generally cannot reveal those specific site(s) of unsaturation. Herein, we describe a novel and versatile workflow whereby fatty acids are first converted to fixed charge N-(4-aminomethylphenyl)pyridinium (AMPP) derivatives and subsequently subjected to ozone-induced dissociation (OzID) on a modified triple quadrupole mass spectrometer. The AMPP modification enhances the detection of fatty acids introduced by direct infusion. Fragmentation of the derivatized fatty acids also provides diagnostic fragment ions upon collision-induced dissociation that can be targeted in precursor ion scans to subsequently trigger OzID analyses in an automated data-dependent workflow. It is these OzID analyses that provide unambiguous assignment of carbon-carbon double bond locations in the AMPP-derivatized fatty acids. The performance of this analysis pipeline is assessed in profiling the patterns of unsaturation in fatty acids within the complex biological secretion vernix caseosa. This analysis uncovers significant isomeric diversity within the fatty acid pool of this sample, including a number of hitherto unreported double bond positional isomers that hint at the activity of potentially new metabolic pathways.
Collapse
|
35
|
Strnad Š, Pražienková V, Sýkora D, Cvačka J, Maletínská L, Popelová A, Vrkoslav V. The use of 1,5-diaminonaphthalene for matrix-assisted laser desorption/ionization mass spectrometry imaging of brain in neurodegenerative disorders. Talanta 2019; 201:364-372. [DOI: 10.1016/j.talanta.2019.03.117] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/29/2019] [Accepted: 03/30/2019] [Indexed: 12/17/2022]
|
36
|
Kirakci K, Zelenka J, Rumlová M, Cvačka J, Ruml T, Lang K. Cationic octahedral molybdenum cluster complexes functionalized with mitochondria-targeting ligands: photodynamic anticancer and antibacterial activities. Biomater Sci 2019; 7:1386-1392. [PMID: 30656318 DOI: 10.1039/c8bm01564c] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Octahedral molybdenum cluster complexes have recently come forth as pertinent singlet oxygen photosensitizers towards biological applications. Still, their phototoxic efficiency in the absence of nanocarriers remains limited due to their poor cellular uptake. Here, two cationic octahedral molybdenum cluster complexes, bearing carboxylate ligands with triphenylphosphonium (1) or N-methyl pyridinium (2) mitochondria-targeting terminal functions, have been designed and synthesized. Their photophysical properties in water and in vitro biological activity were investigated in the context of blue-light photodynamic therapy of cancer and photoinactivation of bacteria. Upon blue light irradiation, complex 1 displays red luminescence with a quantum yield of 0.24 in water, whereas complex 2 is much less emissive (ΦL < 0.01). Nevertheless, both complexes efficiently produce singlet oxygen, O2(1Δg). Complex 1 is rapidly internalized into HeLa cells and accumulated in mitochondria, followed by relocation to lysosomes and clearance at longer times. In contrast, the more hydrophilic 2 is not internalized into HeLa cells, highlighting the effect of the apical ligands on the uptake properties. The treatment with 1 results in an intensive phototoxic effect under 460 nm irradiation (IC50 = 0.10 ± 0.02 μM), which exceeds by far those previously reported for octahedral cluster-based molecular photosensitizers. The ratio between phototoxicity and dark toxicity is approximately 50 and evidences a therapeutic window for the application of 1 in blue-light photodynamic therapy. Complex 1 also enters and efficiently photoinactivates Gram-positive bacteria Enterococcus faecalis and Staphylococcus aureus, documenting its suitability as a blue-light photosensitizer for antimicrobial applications.
Collapse
|
37
|
Bassanini I, Kapešová J, Petrásková L, Pelantová H, Markošová K, Rebroš M, Valentová K, Kotik M, Káňová K, Bojarová P, Cvačka J, Turková L, Ferrandi EE, Bayout I, Riva S, Křen V. Glycosidase‐Catalyzed Synthesis of Glycosyl Esters and Phenolic Glycosides of Aromatic Acids. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201900259] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
|
38
|
Tok OL, Lang K, Růžička A, Cvačka J. Helicenes Built from Silacyclopentadienes via Ring-by-Ring Knitting of the Helical Framework. Angew Chem Int Ed Engl 2019; 58:1654-1658. [PMID: 30548911 DOI: 10.1002/anie.201811140] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 11/14/2018] [Indexed: 12/25/2022]
Abstract
Despite the apparent diversity of the protocols developed for the synthesis of helicenes, they essentially follow the same strategy: the closure of one, or several, internal rings in a key step. Herein, we report the synthesis of a new family of the heterohelicenes consisting of fused silacyclopentadiene rings formed via a facile and novel process. The treatment of oligo(alkynilydenesilylene) precursors of type H2 C=CH-(SiMe2 -C≡C)n -R (n=3-7), bearing a vinyl group on the terminal silicon atom, with 9-borabicyclononane leads first to 1,2-hydroboration of the terminal double bond which then continues with a cascade of intramolecular 1,1-carboboration reactions accompanied with the closure of a new silole ring after each step affording the target silahelicenes with, currently, up to seven condensed silole rings and with excellent yields. According XRD analysis, the seven fused silole rings of the heptacyclic compound 11 b form an almost complete turn of a helix. The presented one-pot sequence of reactions is the first example of ring-by-ring knitting of a helical framework starting from easily available linear precursors.
Collapse
|
39
|
Palma-Onetto V, Pflegerová J, Plarre R, Synek J, Cvačka J, Sillam-Dussès D, Šobotník J. The labral gland in termites: evolution and function. Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/bly212] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
40
|
Tok OL, Lang K, Růžička A, Cvačka J. Helicenes Built from Silacyclopentadienes via Ring‐by‐Ring Knitting of the Helical Framework. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201811140] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
41
|
Bojarová P, Kulik N, Slámová K, Hubálek M, Kotik M, Cvačka J, Pelantová H, Křen V. Selective β-N-acetylhexosaminidase from Aspergillus versicolor—a tool for producing bioactive carbohydrates. Appl Microbiol Biotechnol 2019; 103:1737-1753. [DOI: 10.1007/s00253-018-9534-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 11/05/2018] [Accepted: 11/17/2018] [Indexed: 12/21/2022]
|
42
|
Vrkoslav V, Muck A, Brown JM, Hubálek M, Cvačka J. The matrix-assisted laser desorption/ionisation in-source decay of peptides using ion mobility enabled quadrupole-time-of-flight mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2018; 32:2099-2105. [PMID: 30230090 DOI: 10.1002/rcm.8284] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 09/12/2018] [Accepted: 09/13/2018] [Indexed: 06/08/2023]
Abstract
RATIONALE In-source decay (ISD) matrix-assisted laser desorption/ionisation (MALDI) mass spectrometry with a 1,5-diaminonaphthalene (1,5-DAN) matrix is used for the structural characterisation of peptides. However, MALDI spectra are intrinsically complicated by the presence of matrix ions, which interfere with the peptide fragments. This may cause false-positive results or reduced sequence coverage. This paper reports investigations of ISD processes in an intermediate pressure MALDI ion source and a protocol for the removal of interfering ions using ion mobility separation (IMS). METHODS An intermediate pressure MALDI source of a Q-IMS-Q-TOF instrument (Synapt G2) has been employed for the ISD of selected peptides using a 1,5-DAN matrix. RESULTS Successful coupling of the MALDI source tuned for ISD experiments using IMS is demonstrated. The IMS made it possible to remove interfering matrix ions effectively from the spectra and thus to increase the confidence of spectral interpretation. Extensive fragment series corresponding to N-Cα bond cleavages were observed under optimised conditions; on the other hand, weaker series of ions caused by peptide bond cleavages were prevalent for default conditions and/or the α-hydroxycinnamic acid matrix. CONCLUSIONS Ion mobility has been used for the elimination of matrix ions. The technique has been applied to top-down sequencing of non-tryptic peptides, such as the human palmitoylated analogue of prolactin-releasing peptide used in recent obesity studies, and human and insect antimicrobial peptides.
Collapse
|
43
|
Harazim E, Vrkoslav V, Buděšínský M, Harazim P, Svoboda M, Plavka R, Bosáková Z, Cvačka J. Nonhydroxylated 1- O-acylceramides in vernix caseosa. J Lipid Res 2018; 59:2164-2173. [PMID: 30254076 PMCID: PMC6210899 DOI: 10.1194/jlr.m088864] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 09/21/2018] [Indexed: 01/22/2023] Open
Abstract
Vernix caseosa, the waxy substance that coats the skin of newborn babies, has an extremely complex lipid composition. We have explored these lipids and identified nonhydroxylated 1-O-acylceramides (1-O-ENSs) as a new class of lipids in vernix caseosa. These ceramides mostly contain saturated C11-C38 ester-linked (1-O) acyls, saturated C12-C39 amide-linked acyls, and C16-C24 sphingoid bases. Because their fatty acyl chains are frequently branched, numerous molecular species were separable and detectable by HPLC/MS: we found more than 2,300 molecular species, 972 of which were structurally characterized. The most abundant 1-O-ENSs contained straight-chain and branched fatty acyls with 20, 22, 24, or 26 carbons in the 1-O position, 24 or 26 carbons in the N position, and sphingosine. The 1-O-ENSs were isolated using multistep TLC and HPLC and they accounted for 1% of the total lipid extract. The molecular species of 1-O-ENSs were separated on a C18 HPLC column using an acetonitrile/propan-2-ol gradient and detected by APCI-MS, and the structures were elucidated by high-resolution and tandem MS. Medium-polarity 1-O-ENSs likely contribute to the cohesiveness and to the waterproofing and moisturizing properties of vernix caseosa.
Collapse
|
44
|
Valentová K, Purchartová K, Rydlová L, Roubalová L, Biedermann D, Petrásková L, Křenková A, Pelantová H, Holečková-Moravcová V, Tesařová E, Cvačka J, Vrba J, Ulrichová J, Křen V. Sulfated Metabolites of Flavonolignans and 2,3-Dehydroflavonolignans: Preparation and Properties. Int J Mol Sci 2018; 19:E2349. [PMID: 30096957 PMCID: PMC6121260 DOI: 10.3390/ijms19082349] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 07/31/2018] [Accepted: 08/06/2018] [Indexed: 12/16/2022] Open
Abstract
Silymarin, an extract from milk thistle (Silybum marianum) fruits, is consumed in various food supplements. The metabolism of silymarin flavonolignans in mammals is complex, the exact structure of their metabolites still remains partly unclear and standards are not commercially available. This work is focused on the preparation of sulfated metabolites of silymarin flavonolignans. Sulfated flavonolignans were prepared using aryl sulfotransferase from Desulfitobacterium hafniense and p-nitrophenyl sulfate as a sulfate donor and characterized by high-resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR). Their 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and N,N-dimethyl-p-phenylenediamine (DMPD) radical scavenging; ferric (FRAP) and Folin⁻Ciocalteu reagent (FCR) reducing activity; anti-lipoperoxidant potential; and effect on the nuclear erythroid 2-related factor 2 (Nrf2) signaling pathway were examined. Pure silybin A 20-O-sulfate, silybin B 20-O-sulfate, 2,3-dehydrosilybin-20-O-sulfate, 2,3-dehydrosilybin-7,20-di-O-sulfate, silychristin-19-O-sulfate, 2,3-dehydrosilychristin-19-O-sulfate, and silydianin-19-O-sulfate were prepared and fully characterized. Sulfated 2,3-dehydroderivatives were more active in FCR and FRAP assays than the parent compounds, and remaining sulfates were less active chemoprotectants. The sulfated flavonolignans obtained can be now used as authentic standards for in vivo metabolic experiments and for further research on their biological activity.
Collapse
|
45
|
Vrkoslav V, Rumlová B, Strmeň T, Nekvasilová P, Šulc M, Cvačka J. Applicability of low-flow atmospheric pressure chemical ionization and photoionization mass spectrometry with a microfabricated nebulizer for neutral lipids. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2018; 32:639-648. [PMID: 29457286 DOI: 10.1002/rcm.8086] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 02/05/2018] [Accepted: 02/06/2018] [Indexed: 06/08/2023]
Abstract
RATIONALE Mass spectrometry with atmospheric pressure chemical ionization (APCI) or photoionization (APPI) is widely used for neutral lipids involved in many fundamental processes in living organisms. Commercial APCI and APPI sources operate at high flow rates compatible with conventional high-performance liquid chromatography (HPLC). However, lipid analysis is often limited by a small amount of sample, which requires low flow rate separations like capillary or micro-HPLC. Therefore, APCI and APPI suitable for microliter-per-minute flow rates need to be developed and applied for neutral lipids. METHODS A micro-APCI/APPI source with a heated chip nebulizer was assembled and mounted on a Thermo ion trap instrument. The ion source operated in APCI, APPI or dual mode was optimized for low microliter-per-minute sample flow rates. The source performance was investigated for squalene, wax esters, fatty acid methyl esters, triacylglycerols, and cholesterol. RESULTS The ion source behaved as a mass-flow-sensitive detector. Direct infusion of methyl oleate showed superior analytical figures of merit when compared with high-flow ion sources. A detection limit of 200 pmol/mL and a linear dynamic range spanning three orders of magnitude were measured for micro-APCI. The mass spectra of most lipids differed from high flow rate spectra. Unlike micro-APCI, micro-APPI spectra were complicated by odd-electron species. Dual APCI/APPI mode did not show any benefits for neutral lipids. Applications for lipid samples were demonstrated. CONCLUSIONS Micro-APCI-MS is a useful detection technique for neutral lipids at microliter-per-minute flow rates. It offers high sensitivity and high quality of spectra in direct infusion mode and promises successful utilization in capillary and micro-HPLC applications.
Collapse
|
46
|
Sobol M, Krausová A, Yildirim S, Kalasová I, Fáberová V, Vrkoslav V, Philimonenko V, Marášek P, Pastorek L, Čapek M, Lubovská Z, Uličná L, Tsuji T, Lísa M, Cvačka J, Fujimoto T, Hozak P. Nuclear phosphatidylinositol 4,5-bisphosphate islets contribute to efficient RNA polymerase II-dependent transcription. J Cell Sci 2018; 131:jcs.211094. [PMID: 29507116 DOI: 10.1242/jcs.211094] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 02/22/2018] [Indexed: 12/18/2022] Open
Abstract
This paper describes a novel type of nuclear structure - nuclear lipid islets (NLIs). They are of 40-100 nm with a lipidic interior, and phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] molecules comprise a significant part of their surface. Most of NLIs have RNA at the periphery. Consistent with that, RNA is required for their integrity. The NLI periphery is associated with Pol II transcription machinery, including the largest Pol II subunit, transcription factors and NM1 (also known as NMI). The PtdIns(4,5)P2-NM1 interaction is important for Pol II transcription, since NM1 knockdown reduces the Pol II transcription level, and the overexpression of wild-type NM1 [but not NM1 mutated in the PtdIns(4,5)P2-binding site] rescues the transcription. Importantly, Pol II transcription is dependent on NLI integrity, because an enzymatic reduction of the PtdIns(4,5)P2 level results in a decrease of the Pol II transcription level. Furthermore, about half of nascent transcripts localise to NLIs, and transcriptionally active transgene loci preferentially colocalise with NLIs. We hypothesize that NLIs serve as a structural platform that facilitates the formation of Pol II transcription factories, thus participating in the formation of nuclear architecture competent for transcription.
Collapse
|
47
|
Strmeň T, Vrkoslav V, Pačes O, Cvačka J. Evaluation of an ion source with a tubular nebulizer for microflow atmospheric pressure chemical ionization. MONATSHEFTE FUR CHEMIE 2018. [DOI: 10.1007/s00706-018-2172-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
48
|
Daňhel A, Trošanová Z, Balintová J, Simonová A, Pospíšil L, Cvačka J, Hocek M, Fojta M. Electrochemical reduction of azidophenyl-deoxynucleoside conjugates at mercury surface. Electrochim Acta 2018. [DOI: 10.1016/j.electacta.2017.10.128] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
49
|
Mundil R, Sokolohorskyj A, Hošek J, Cvačka J, Císařová I, Kvíčala J, Merna J. Nickel and palladium complexes with fluorinated alkyl substituted α-diimine ligands for living/controlled olefin polymerization. Polym Chem 2018. [DOI: 10.1039/c8py00201k] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Living/controlled olefin polymerization is displayed by novel nickel and palladium diimine catalysts with fluorinated tails.
Collapse
|
50
|
Valentová K, Káňová K, Di Meo F, Pelantová H, Chambers CS, Rydlová L, Petrásková L, Křenková A, Cvačka J, Trouillas P, Křen V. Chemoenzymatic Preparation and Biophysical Properties of Sulfated Quercetin Metabolites. Int J Mol Sci 2017; 18:ijms18112231. [PMID: 29068411 PMCID: PMC5713201 DOI: 10.3390/ijms18112231] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/02/2017] [Accepted: 10/20/2017] [Indexed: 11/28/2022] Open
Abstract
Sulfated quercetin derivatives are important authentic standards for metabolic studies. Quercetin-3′-O-sulfate, quercetin-4′-O-sulfate, and quercetin-3-O-sulfate as well as quercetin-di-O-sulfate mixture (quercetin-7,3′-di-O-sulfate, quercetin-7,4′-di-O-sulfate, and quercetin-3′,4′-di-O-sulfate) were synthetized by arylsulfotransferase from Desulfitobacterium hafniense. Purified monosulfates and disulfates were fully characterized using MS and NMR and tested for their 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) and N,N-dimethyl-p-phenylenediamine (DMPD) radical scavenging, Folin-Ciocalteau reduction (FCR), ferric reducing antioxidant power (FRAP), and anti-lipoperoxidant activities in rat liver microsomes damaged by tert-butylhydroperoxide. Although, as expected, the sulfated metabolites were usually less active than quercetin, they remained still effective antiradical and reducing agents. Quercetin-3′-O-sulfate was more efficient than quercetin-4′-O-sulfate in DPPH and FCR assays. In contrast, quercetin-4′-O-sulfate was the best ferric reductant and lipoperoxidation inhibitor. The capacity to scavenge ABTS+• and DMPD was comparable for all substances, except for disulfates, which were the most efficient. Quantum calculations and molecular dynamics simulations on membrane models supported rationalization of free radical scavenging and lipid peroxidation inhibition. These results clearly showed that individual metabolites of food bioactives can markedly differ in their biological activity. Therefore, a systematic and thorough investigation of all bioavailable metabolites with respect to native compounds is needed when evaluating food health benefits.
Collapse
|