Bzdzion L.,Wroclaw Research Center Ltd. |
Krezel H.,Wroclaw Research Center Ltd. |
Wrzeszcz K.,Wroclaw Research Center Ltd. |
Grzegorek I.,Wroclaw Research Center Ltd. |
And 4 more authors.
Acta Biochimica Polonica | Year: 2017
Enteropathogenic E. coli (EPEC) is a human pathogen using type III secretion system for delivery of proteins directly into the human host. The system contains a single ATPase, EscN, which is essential for uncoupling of proteins from their complexes with chaperones before the delivery. The structure of EscN ATPase (PDB code: 2obm) was used to screen computationally for small molecule inhibitors blocking its active site. Two lead candidates were examined but only one, Compound 54, was selected for further optimization. After extended QSAR optimization, two derivatives were found to be competitive inhibitors of EscN capable of blocking ATPase activity with a Ki below 50 μM. One candidate, WEN05-03, with a Ki=16±2 μM, was also minimally toxic to mammalian cells as determined by other assays. In the cell infection model of HeLa cells with EPEC, Compound WEN05-03 completely blocked actin cluster formation at 100 μM concentration, when analyzed by confocal microscopy. The second best inhibitor of EscN ATPase activity was WEN04-34 with a Ki=46±2 μM. However, the compound was highly toxic to the BALB/3T3 cell line. In summary, the work identifies a compound blocking bacterial ATPase in its active site without causing cellular toxicity to the host cells. It is the first report showing feasibility of using bacterial virulence system ATPase as a target for safe, non-toxic compounds and offering a proof-of-concept for non-antibiotic alternatives.
SMOLAREK J.,University of Silesia |
TRELA W.,The Polish Geological Institute National Research Institute |
BOND D.P.G.,University of Hull |
MARYNOWSKI L.,University of Silesia |
MARYNOWSKI L.,Wroclaw Research Center Ltd
Geological Magazine | Year: 2016
The stratigraphic variability and geochemistry of Llandovery/Wenlock (L/W) Series boundary sediments in Poland reveals that hemipelagic sedimentation under an anoxic/euxinic water column was interrupted by low-density bottom currents or detached diluted turbid layers that resulted in intermittent seafloor oxygenation. Total organic carbon values and inorganic proxies throughout the Wilków 1 borehole section suggest variable redox conditions. U/Mo ratios > 1 throughout much of the Aeronian and Telychian stages, together with an absence of pyrite framboids, suggest oxygenated conditions prevailed. However, elevated total organic carbon near the Aeronian/Telychian boundary, together with increased U/Th and V/(V + Ni) ratios and populations of small pyrite framboids are consistent with the development of dysoxic/anoxic conditions at that time. U/Th, V/Cr and V/(V + Ni) ratios, as well as Uauthig and Mo concentrations, suggest that during the Ireviken black shale deposition, bottom-water conditions deteriorated from oxic during Telychian time to mostly suboxic/anoxic immediately prior to the L/W boundary, before a brief reoxygenation at the end of the Ireviken black shale sedimentation in the Sheinwoodian Stage. Rapid fluctuations in U/Mo during the Ireviken Event are characteristic of fluctuating redox conditions that culminated in an anoxic/euxinic seafloor in Sheinwoodian time. Following Ireviken black shale deposition, conditions once again became oxygen deficient with the development of a euxinic zone in the water column. The Aeronian to Sheinwoodian deep-water redox history was unstable, and rapid fluctuations of the chemocline across the L/W Series boundary probably contributed to the Ireviken Event extinctions, which affected mainly pelagic and hemipelagic fauna. Copyright © Cambridge University Press 2016
Klocek J.,TU Brandenburg |
Henkel K.,TU Brandenburg |
Kolanek K.,TU Brandenburg |
Broczkowska K.,Wroclaw University of Technology |
And 4 more authors.
Thin Solid Films | Year: 2012
Among an extremely large number of possible fullerene applications in the field of electronics, optics and photovoltaics, C 60-cages are also considered as a promising dopant for low dielectric constant (low-k) materials. In this study, we incorporated C 60 species into a 3-aminopropyltrimethoxysilane (APTMS) based material. We prepared thin films by spin coating. Using X-ray photoelectron spectroscopy we analyzed the time-related interactions between the components of the prepared samples and the influence of the C 60 replacement by its better soluble derivative [6,6]-phenyl-C 61-butyric acid methyl ester (PCBM) on the chemical properties of the material. We applied atomic force microscopy to investigate the surface texture and thicknesses of the obtained films. In order to obtain information concerning the electrical properties of the material we performed capacitance-voltage characterization. We have proven that the increase of C 60 species realized by PCBM incorporation within the APTMS-based matrix reduces the dielectric constant of the examined films while preserving its homogeneity. © 2011 Elsevier B.V. All rights reserved.
Smolarek J.,University of Silesia |
Marynowski L.,University of Silesia |
Spunda K.,Wroclaw Research Center Ltd. |
Trela W.,Polish Geological Institute National Research Institute
Mineralogia | Year: 2014
A number of independent methods have been used to measure the thermal maturity of Silurian rocks from the Holy Cross Mountains in Poland. Black shales are characterized by diverse TOC values varying from 0.24-7.85%. Having calculated vitrinite equivalent reflectance using three different formulas, we propose that the most applicable values for the Silurian rocks are those based on Schmidt et al. (2015) equation. Based on this formula, the values range from % 0.71 VReqvVLR (the vitrinite equivalent reflectance of the vitrinite-like macerals) to % 1.96 VReqvVLR. Alternative, complementary methods including Rock Eval pyrolysis and parameters based on organic compounds (CPI, Pr/n-C17, Ph/n-C18, MPI1, and MDR) from extracts did not prove adequate as universal thermal maturity indicators. We have confirmed previous suggestions that Llandovery shales are the most likely Silurian source rocks for the generation of hydrocarbons in the HCM. © 2014 Justyna Smolarek et al., published by De Gruyter Open.
Kubik R.,University of Silesia |
Kubik R.,Wroclaw Research Center Ltd |
Uhl D.,Senckenberg Forschungsinstitut and Naturmuseum Frankfurt |
Marynowski L.,University of Silesia
Annales Societatis Geologorum Poloniae | Year: 2015
Charcoals from the Upper Triassic vertebrate-bearing clays of the Zawiercie area (Upper Silesia, S-Poland) were analyzed using petrographic methods, to reconstruct burning temperatures as well as taphonomic processes. SEM and reflected light microscopy show excellent preservation of charcoals most probable connected with early diagenetic permineralization by calcite. The charcoal was assigned to three morphotypes, probably corresponding to three different fossil taxa. Fusinite reflectance data suggest, that the highest temperature reached above 600 °C (fusinite reflectance of 3.59%), what counterparts to the lower limit crown fire temperature. The values for most of the samples are lower (ca. 1% to 2.5%) what is typical for surface fires. In many cases fusinite reflectance values depends on the measured zone within the sample. Such zonation formed due to charring temperature differences. In zones remote from the potential fire source, reflectance values gradually decreases. It implies that calculation of fire temperatures based on average fusinite reflectance values might be too far-reaching simplification. Occurrence of fungal hyphae within the charcoal supports the interpretation of a predomination of surface fire, consuming dead twigs and stems. The low content of micro-charcoals in charcoal-bearing rocks as well as roanded to sub-roanded shapes of large specimens indicates that they were transported after burning, deposited away from the burning area, and finally early diagenetic mineralization. © 2015, Geological Society of Poland. All rights reserved.
Marynowski L.,University of Silesia |
Kubik R.,University of Silesia |
Kubik R.,Wroclaw Research Center Ltd. |
Uhl D.,Senckenberg Forschungsinstitut und Naturmuseum Frankfurt |
Simoneit B.R.T.,Oregon State University
Organic Geochemistry | Year: 2014
Upper Triassic charcoal extracts were studied using gas chromatography-mass spectrometry (GC-MS) to recognize their molecular composition. Extractable compounds were divided into: (i) biomarkers, i.e. diagenetically changed primary wood components and (ii) products of combustion. Major compounds in the first group were: 1,2,5-trimethylnaphthalene and 1,2,5,6-tetramethylnaphthalene, cadalene, dehydroabietane, simonellite and retene. All of these are derived from resins. Moreover, propyl phenols, butyl acetophenones and pentyl acetophenones, as products of lignin breakdown, as well as fatty acids with a predominance of palmitic acid, typical constituents of wood, were also detected. Polycyclic aromatic hydrocarbons (PAHs), as well as ketones and aryl phenols, considered as high temperature combustion products, occurred at relatively low concentration in the samples due to their enhanced solubility in gelified, non-charred wood fragments, and vaporization of the major part of the burn products. Despite the low PAH concentrations, their distribution, with a significant contribution from typical pyrolytic compounds such as anthracene, 4H-cyclopenta[. def]phenanthrene, benz[. a]anthracene and benzo[. a]pyrene was typical for rapid combustion. We propose to estimate paleo-wildfire temperature based on the PAH concentrations in the paleo-charcoal samples. The presence of thermally less stable organic compounds and low PAH abundances indicates a temperature < 400. °C. High PAH amounts seem to be characteristic for charring between 400 and 500. °C. Above these temperatures PAH concentrations again decrease, but less stable compounds are absent. © 2014 Elsevier Ltd.
Deperasinska I.,Polish Academy of Sciences |
Szemik-Hojniak A.,Wrocław University |
Osowska K.,Wrocław University |
Rode M.F.,Polish Academy of Sciences |
And 5 more authors.
Journal of Photochemistry and Photobiology A: Chemistry | Year: 2011
The Cadiot-Chodkiewicz type C2-elongation of p-tolylacetylene followed by dimerization of the resulted diyne p-CH3C 6H4(C≡C)2TMS (1) gave thermally stable octatetrayne p-CH3C6H4(C≡C) 4-p-C6H4CH3 (2) as light yellow powder in 75% yield. Compound 2 was characterized by spectroscopic methods and X-ray crystallography. Careful analysis of the crystal data revealed high degree of chain linearity with a potential for 1,n-topochemical polymerization. Next, photophysical properties of 2 were studied in details by experimental and advanced theoretical methods (ab initio HF as well as DFT calculations involving both the ground and excited state geometry optimization). These properties are similar to the properties of the parent polyyne C6H 5(C≡C)4C6H5 previously described in literature (in particular, the lowest electronic excited singlet state (S1) of 2 is a dark state). This was confirmed by the experimental facts, namely, few progressions of the stretching mode (a g) of the polyyne chain, starting from different "false origins" lying below the second excited (bright) state (S2), were observed in the fluorescence excitation spectrum. The red shift of the electronic spectra (155 cm-1 and 300 cm-1 for absorption and fluorescence, respectively) and an increase of an energy gap between S 1 and S2 states by 450 cm-1 are the effects of methylation of C6H5(C≡C)4C 6H5 to 2. Theoretical results showed that in the excited state of 2 a shortening of single bonds and elongation of triple bonds occurred. This is in accordance with an observation of a long progression of the stretching vibration mode in the experimental absorption spectrum of 2. Besides that, stretching vibration of the polyyne chain is also active in the fluorescence spectra. © 2010 Elsevier B.V. All right reserved.
Marczak J.,Wroclaw Research Center Ltd. |
Kargol M.,Wroclaw Research Center Ltd. |
Psarski M.,University of Lodz |
Celichowski G.,University of Lodz
Applied Surface Science | Year: 2016
Preparation of superhydrophobic materials inspired by nature has attracted a great scientific interest in recent decades. Some of these materials have hierarchical lotus-like structures, i.e. micro- and nano-objects coated by hydrophobic compounds. A major challenge of applying the superhydrophobic surfaces for the self-cleaning coatings preparation is their improved efficiency in varying atmospheric conditions, e.g. UV light. The objective of this research work was to investigate the effect of the different chemical structure and the surface free energy on the hydrophobic and tribological properties of the alkylsilanes and fluoroalkylsilanes deposited on silicon wafers, glass slides and epoxy resin. Tribological and hydrophobic properties of the modified surfaces were correlated with their chemical structures. Chemical structures of the deposited materials were examined by using Fourier transform infrared (FT-IR) spectroscopy and hydrophobic properties were investigated by water contact angle (WCA) and surface free energy (SFE) measurements. The modified surfaces exhibited water contact angles of above 100° for the selected modifiers. It was noticed that the replacement of hydrogen atoms by fluorine atoms in alkyl chain caused an increase in the water contact angle values and a decrease in friction coefficients. The obtained results showed that the carbon chain length of a modifier and its chemical structure can strongly affect the hydrophobic and tribological properties of the modified surfaces. The highest values of WCA, lowest values of SFE and coefficient of friction were obtained for samples covered by fluorinated compounds. Moreover, some preliminary aging test was performed to give an insight into the effectiveness of deposited alkylsilanes and fluoroalkylsilanes coatings. After accelerated UV exposure, no significant changes in the chemical structure, hydrophobic and tribological properties of the modified surfaces were noticed. The samples degradation was not observed and hydrophobic effect was maintained in UV light what can be promising in efficient self-cleaning coatings obtaining. © 2016 Elsevier B.V.
Marczak J.,Wroclaw Research Center Ltd. |
Slupski P.,Wroclaw Research Center Ltd. |
Kunicki P.,Wroclaw Research Center Ltd. |
Komorowska K.,Wroclaw Research Center Ltd.
IEEE-NANO 2015 - 15th International Conference on Nanotechnology | Year: 2015
Soft lithography and UV-NIL are important technologies for micro- and nano- structures replication . It is possible to adapt surface structures preparation for many applications regarding e.g. opto-fluidic on-chip microscopy, wetting or reflection properties . Light microscopy has been one of the most common tools in biological research, because of its high resolution and non-invasive nature of the light. Fresnel lens can be used in passive and active high quality polymer-based on-chip components for integrated photonics circuits . In presented soft lithography technique the various materials were used for Fresnel lens replication: PDMS, h-PDMS and thiol-ene-epoxy resin. Mentioned polymers are characterized by high flexibility and transparency with minimal color. The silicon matrices replication process involves two main steps: anti-adhesive layer preparation and polymer deposition. The influence of structures geometry on the optical properties Fresnel lens has been investigated. The topography of obtained replicas was characterized using the atomic force microscopy (AFM) and scanning electron microscopy (SEM). The efficiency of light focus of the selected wavelength has been checked by intensity measurement using a standard optical microscope. As a result of replication 10□m diameter Fresnel lenses have been prepared. © 2015 IEEE.
PubMed | Wroclaw Research Center Ltd. and Polish Academy of Sciences
Type: | Journal: Acta biochimica Polonica | Year: 2016
Enteropathogenic E. coli (EPEC) is a human pathogen using type III secretion system for delivery of proteins directly into the human host. The system contains a single ATPase, EscN, which is essential for uncoupling of proteins from their complexes with chaperones before the delivery. The structure of EscN ATPase (PDB code: 2obm) was used to screen computationally for small molecule inhibitors blocking its active site. Two lead candidates were examined but only one, Compound 54, was selected for further optimization. After extended QSAR optimization, two derivatives were found to be competitive inhibitors of EscN capable of blocking ATPase activity with a K