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  • 1
    Language: English
    In: Chemistry and Physics of Lipids, 2011, Vol.164(4), pp.266-275
    Description: The presence of charged lipids in the cell membrane constitutes the background for the interaction with numerous membrane proteins. As a result, the valence of the lipids plays an important role concerning their lateral organization in the membrane and therefore the very manner of this interaction. This present study examines this aspect, particularly regarding to the interaction of the anionic lipid DPPS with the highly basic charged effector domain of the MARCKS protein, examined in monolayer model systems. Film balance, fluorescence microscopy and X-ray reflection/diffraction measurements were used to study the behavior of DPPS in a mixture with DPPC for its dependance on the presence of MARCKS (151–175). In the mixed monolayer, both lipids are completely miscible therefore DPPS is incorporated in the ordered crystalline DPPC domains as well. The interaction of MARCKS peptide with the mixed monolayer leads to the formation of lipid/peptide clusters causing an elongation of the serine group of the DPPS up to 7 Å in direction to surface normal into the subphase. The large cationic charge of the peptide pulls out the serine group of the interface which simultaneously causes an elongation of the phosphodiester group of the lipid fraction too. The obtained results were used to compare the interaction of MARCKS peptide with the polyvalent PIP in mixed monolayers. On this way we surprisingly find out, that the relative small charge difference of the anionic lipids causes a significant different interaction with MARCKS (151–175). The lateral arrangement of the anionic lipids depends on their charge values and determines the diffusion of the electrostatic binding clusters within the membrane.
    Keywords: Anionic Lipids ; Marcks (151–175) ; Monolayer ; Isotherms ; Fluorescence Microscopy ; X-Ray Diffraction ; Chemistry ; Anatomy & Physiology
    ISSN: 0009-3084
    E-ISSN: 1873-2941
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  • 2
    Language: English
    In: Chemical Physics Letters, 1990, Vol.167(6), pp.535-541
    Description: The IR multiphoton excitation and the frequency, fluence and intensity dependence of the IR-laser chemical yields of CF 2 ClCH 2 Cl have been studied in the fluence range of 1 to 10 J cm −2 yielding a steady-state constant k (st)/ I =0.74×10 6 s −1 MW −1 cm 2 which is approximately independent of intensity. Time-resolved IR absorption spectroscopy with diode laser sources has been used to observe the nascent HCl during the first few 100 ns indicating a population inversion between the levels ν=1, J =4 and ν=2, J =5. At low reactant pressures ( p ⩽10 Pa) the time-resolved measurement gives a steady-state rate constant consistent with the theoretical result adjusted to the static yield measurements. The capability of state-selective and time-resolved IR spectroscopy is thus demonstrated, giving real-time determinations of rate constants.
    Keywords: Chemistry
    ISSN: 0009-2614
    E-ISSN: 1873-4448
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  • 3
    Language: German
    In: Journal of Chromatography A, 1983, Vol.259, pp.243-254
    Description: Gas chromatographic studies of perfluorocarbon compounds. II. Gas chromatographic separation of mixtures of long-chain perfluoroalkanes and -alkenes. The Kováts retention indices of some perfluoro- n -alkanes, perfluoro- n -alk-1-enes, branched-chain perfluoroalkenes, cyclic perfluorocarbons, 1-H-perfluoro- n -al-kanes are determined on several fluoro-containing and non-fluoro-containing liquid phases and on some adsorbents. The results are compared with each other and give information about the nature and degree of interaction processes concerning the type of perfluorocarbon compound and liquid phase. Es wurden die Retentionswerte von Perfluor- n -alkanen, Perfluor- n -alk-1-enen, verzweigten Perfluoralkenen, zyklischen Perfluorcarbonen und 1-H-Perfluor- n -alkanen auf fluorhaltigen und nichtfluorhaltigen Trennflüssigkeiten sowie an einigen Adsorbentien ertmittelt. Fluorhaltige Trennflüssigkeiten ergaben höhere Retentionswerte als nichtfluorhaltige. Von den nichtfluorhaltigen stationären Phasen haben solche mit hohem Anteil an starken π-Elektronensystemen (z.B. DEGS) für die Trennung von Perfluorcarbongemischen die günstigsten Eigenschaften. Adsorbentien wirken entsprechend ihrer spezifischen Oberfläche und dem Gehalt an aktiven Gruppen.
    Keywords: Chemistry
    ISSN: 0021-9673
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  • 4
    In: PLoS ONE, 2013, Vol.8(6)
    Description: Protective properties of moderate wine consumption against cancers, cardiovascular, metabolic and degenerative diseases have been reported in various clinical studies. Here, we analysed the effect of red wine (RW) and white wine (WW) on myelination using an in vitro embryonic co-culture mouse model. The total amount of myelin was found to be significantly increased after RW and WW treatment, while only RW significantly increased the number of internodes. Both types of wine increased rat Schwann cell- (rSC) expression of the NAD+-dependent deacetylase sirtuin-two-homolog 2 (Sirt2), a protein known to be involved in myelination. Detailed chemical analysis of RW revealed a broad spectrum of anthocyanins, piceids, and phenolics, including resveratrol (RSV). In our assay system RSV in low concentrations induced myelination. Furthermore RSV raised intracellular glutathione concentrations in rSCs and in co-cultures and therefore augmented antioxidant capacity. We conclude that wine promotes myelination in a rodent in vitro model by controlling intracellular metabolism and SC plasticity. During this process, RSV exhibits protective properties; however, the fostering effect on myelinaton during exposure to wine appears to be a complex interaction of various compounds.
    Keywords: Research Article ; Biology ; Chemistry ; Medicine
    E-ISSN: 1932-6203
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  • 5
    Language: English
    In: Biochemical and Biophysical Research Communications, 12 October 2007, Vol.362(1), pp.114-119
    Description: Cytochrome P450 monooxygenase from the anaerobic microorganism (CYP152A2) has been produced in . CYP152A2 was shown to bind a broad range of saturated and unsaturated fatty acids and corresponding methyl esters and demonstrated a high peroxygenase activity of up to 200 min with myristic acid. Although a high concentration of hydrogen peroxide of 200 μM was necessary for high activities of the enzyme, it led to a fast enzyme inactivation within 2–4 min. This might reflect the natural function of CYP152A2 as a rapid hydrogen peroxide scavenging enzyme. In two different reconstituted systems with NADPH, CYP152A2 was able to convert 10 times more substrate, if provided with flavodoxin and flavodoxin reductase from and even 30–40 times more substrate with the CYP102A1-reductase from According to the clear preference for hydroxylation at α-position, CYP152A2 can be referred to as fatty acid α-hydroxylase.
    Keywords: Clostridium Acetobutylicum ; P450 Monooxygenase ; Fatty Acids ; Peroxygenase ; Activity Reconstitution ; Biology ; Chemistry ; Anatomy & Physiology
    ISSN: 0006-291X
    E-ISSN: 1090-2104
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  • 6
    Language: German
    In: Journal of Chromatography A, 1978, Vol.147, pp.31-40
    Description: Gas chromatographic studies of perfluorocarbon compounds. Gas chromatographic properties of esters of long-chain perfluorocarbonic acids The Kováts retention indices of some perfluorocarbonic acid esters, ωH-perfluorocarbonic acid esters, and perfluorodicarbonic acid esters are determined on several non-polar and polar liquid phases. The results are compared with each other and give information about nature and degree of interaction processes concerning esters and phases. Es werden die Retentionsindices nach Kováts verschiedener Perfluorcarbonsäure-methylester, ωH-Perfluorcarbonsäure-methylester und Perfluorcarbonsäuredimethylester auf drei unpolaren und vier polaren Trennflüssigkeiten bei 100° bzw. 120° bestimmt. Die Werte werden untereinander und mit denen der analogen Fettsäure-methylester bzw. Dicarbonsäure-dimethylester verglichen. Aus den Ergebnissen wird auf Art und Grad der Wechselwirkungsvorgänge geschlossen.
    Keywords: Chemistry
    ISSN: 0021-9673
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  • 7
    Language: English
    In: Food Chemistry, 2009, Vol.112(2), pp.482-486
    Description: Non-thermal food preservation technology is based on the application of high pressures up to 600 MPa. Here we report a resonance Raman (RR) spectroscopic analysis of smoked salmon meat after high pressure processing. High quality spectra, which can be obtained even from packed salmon without spectral interference of the packing foil, allow determining pressure-dependent irreversible changes of the main RR-active components of salmon meat, astaxanthin and myoglobin/haemoglobin. High pressure-treatment causes a decrease of the relative RR intensities of astaxanthin as probed with 514 nm excitation which is in line with a slight attenuation of the originally intense red colour of the salmon meat. 413-nm excited RR spectra indicate a heterogeneous broadening of astaxanthin bands accompanied by the formation of deoxy-myoglobin or deoxy-haemoglobin. The results suggest that pressure-treatment facilitates the oxidative degradation of astaxanthin coupled to the reduction of metmyoglobin (methaemoglobin).
    Keywords: Resonance Raman ; High Pressure ; Astaxanthin ; Salmon ; Chemistry ; Diet & Clinical Nutrition ; Economics
    ISSN: 0308-8146
    E-ISSN: 1873-7072
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  • 8
    Language: English
    In: Journal of Fluorine Chemistry, 1985, Vol.29(1), pp.199-199
    Description: Mixtures of lower perfluoroalkanes and perfluoroalkenes are formed during the degradation of PTFE under inert conditions with help of accelerated electrons by cleavage of CC and CF bonds. The share of compounds in the range of C 6 to C 14 is used to prepare fluorosurfactants. The gas chromatographic analysis of these mixtures shows their complicated composition. At the following pattern substances the gas chromatographic properties were studied to find out suitable stationary phases: perfluoro-n-alkanes C 7 ;C 6 ;C 10 ), perfluoro-n-hept-1-ene, 1H-perfluoro-n-heptane, perfluoro-methylcyclohexane, perfluoro-4-ethyl-3,4-dimethylhex- 2-ene, perfluorobenzene and perfluorotoluene. A good selectivity and retention is available with fluorine containig stationary phases. Their efficiency depends on their content of fluorine and on the kind and number of functional groups. Liquid phases without any fluorine content show a small separation efficiency, even at a high degree of polarity, because of their very low partition coefficients. Results are submitted with the use of adsorbents(Carbopack C, Chromosorb lol) for the separation of perfluoroalkane- perfluoroalkene-mixtures. The reaction of perfluoroalkenes with nucleophilic agents can be applied in reaction gas chromatography. If polyethyleneimine is used as a liquid phase, straight chain as well as branched chain perfluoroalkenes can be detected in mixtures, because stable compounds are formed which were not eluated.
    Keywords: Chemistry
    ISSN: 0022-1139
    E-ISSN: 1873-3328
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  • 9
    Language: English
    In: BBA - Biomembranes, 2009, Vol.1788(7), pp.1474-1481
    Description: In this present work we have studied the effect of MARCKS (151–175) peptide on a mixed DPPC/PIP monolayer. By means of film balance, fluorescence microscopy, x-ray reflection/diffraction and neutron reflection measurements we detected changes in the lateral organization of the monolayer and changes in the perpendicular orientation of the PIP molecules depending on the presence of MARCKS (151–175) peptide in the subphase. In the mixed monolayer, the PIP molecules are distributed uniformly in the disordered phase of the monolayer, whereas the PI(4,5) groups elongate up to 10 Å below the phosphodiester groups. This elongation forms the precondition for the electrostatic interaction of the MARCKS peptide with the PIP molecules. Due to the enrichment of PIP in the disordered phase, the interaction with the peptide occurs primarily in this phase, causing the PI(4,5) groups to tilt toward the monolayer interface.
    Keywords: Peptide/Monolayer Interaction ; Lateral Organization ; Structural Parameter ; Chemistry
    ISSN: 0005-2736
    E-ISSN: 1879-2642
    E-ISSN: 00063002
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  • 10
    Language: English
    In: Histochemistry and Cell Biology, 2006, Vol.125(3), pp.293-305
    Description: In vitro studies on the pathogenesis in swine have been hampered by the lack of relevant porcine cell lines. Since many bacterial infections are swine-specific, studies on pathogenic mechanisms require appropriate cell lines of porcine origin. We have characterized the permanent porcine intestinal epithelial cell line, IPEC-J2, using a variety of methods in order to assess the usefulness of this cell line as an in vitro infection model. Electron microscopic analyses and histochemical staining revealed the cells to be enterocyte-like with microvilli, tight junctions and glycocalyx-bound mucin. The functional integrity of monolayers was determined by transepithelial electrical resistance (TEER) measurements. Both commensal bacteria and important bacterial pathogens were chosen for study based on their principally different infection mechanisms: obligate extracellular Escherichia coli , facultative intracellular Salmonella and obligate intracellular Chlamydia . We determined the colonization and proliferation of the bacteria on and within the host cells and monitored the host cell response. We verified the expression of mRNAs encoding the cytokines IL-1α, −6, −7, −8, −18, TNF-α and GM-CSF, but not TGF-β or MCP-1. IL-8 protein expression was enhanced by Salmonella invasion. We conclude that the IPEC-J2 cell line provides a relevant in vitro model system for porcine intestinal pathogen–host cell interactions.
    Keywords: Microbial pathogenesis ; In vitro infection model ; Porcine intestinal epithelial cell line
    ISSN: 0948-6143
    E-ISSN: 1432-119X
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