Deletion of hypothetical wall teichoic acid ligases in Staphylococcus aureus activates the cell wall stress response

The Staphylococcus aureus cell wall stress stimulon (CWSS) is activated by cell envelope-targeting antibiotics or depletion of essential cell wall biosynthesis enzymes. The functionally uncharacterized S. aureus LytR-CpsA-Psr (LCP) proteins, MsrR, SA0908 and SA2103, all belong to the CWSS. Although not essential, deletion of all three LCP proteins severely impairs cell division. We show here that VraSR-dependent CWSS expression was up to 250-fold higher in single, double and triple LCP mutants than in wild type S. aureus in the absence of external stress. The LCP triple mutant was virtually depleted of wall teichoic acids (WTA), which could be restored to different degrees by any of the single LCP proteins. Subinhibitory concentrations of tunicamycin, which inhibits the first WTA synthesis enzyme TarO (TagO), could partially complement the severe growth defect of the LCP triple mutant. Both of the latter findings support a role for S. aureus LCP proteins in late WTA synthesis, as in Bacillus subtilis where LCP proteins were recently proposed to transfer WTA from lipid carriers to the cell wall peptidoglycan. Intrinsic activation of the CWSS upon LCP deletion and the fact that LCP proteins were essential for WTA-loading of the cell wall, highlight their important role(s) in S. aureus cell envelope biogenesi

Fluorosolvatochromism of furanyl- and thiophenyl-substituted acetophenones

A series of para-substituted acetophenones bearing a furanyl or a thiophenyl moiety show a large Stokes-shift, which is a function of various solvent properties. Photophysical properties such as emission lifetime of the compounds have been determined using time-correlated-single photon counting to secure the intrinsic fluorescence behaviour. The solvent dependent position of the UV/Vis emission band [small nu, Greek, tilde]max,em of the compounds has been measured in 26 various solvents. The influence of the solvent on [small nu, Greek, tilde]max,em is of very complex nature and mathematically analysed by multiple square linear solvation energy (LSE)-correlation analysis using Catalán's four-solvent parameter set. Solvent acidity has a strong influence on the bathochromic shift of 2,5-disubstituted furan derivatives compared to the non-5-substituted furan and thiophene derivatives, which show a contrary behaviour. Therefore, the 5-cyanofuranyl-substituted acetophenone derivative is useful as a probe for measuring environmental properties by fluorescence spectroscopy.Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich

A Novel Diagnostic Target in the Hepatitis C Virus Genome

Christian Drosten and colleagues develop, validate, and make openly available a prototype hepatitis C virus assay based on the conserved 3' X-tail element, with potential for clinical use in developing countries

Abstracts from the 8th International Conference on cGMP Generators, Effectors and Therapeutic Implications

This work was supported by a restricted research grant of Bayer AG

Polymethacrylat-gebundene chromophore Arylboronsäuren und deren Komplexbildungsverhalten gegenüber Fluorid-Ionen

Gegenstand der vorliegenden Arbeit ist die polymeranaloge Reaktion von chromophoren Aryl-boronsäuren mit 1,2-Diol-basierenden Methacrylat-Copolymeren. Über die Herstellung der dafür benötigten Ausgangsverbindungen sowie deren Charakterisierung mit Hilfe spektroskopischer und thermischer Analysemethoden wird zunächst umfassend berichtet. Hierbei ist u.a. die Auf-klärung der in den Copolymeren aus n-Butylmethacrylat (BMA) und 2,3-Di-hydroxypropylmethacrylat vorliegenden Polymerkonstitution von Interesse. Als chromophore Grundkörper der Arylboronsäuren wurden Indanon- sowie Tricyanofuran-Derivate, aber auch ausgedehnte Elektronensysteme mit einem Nitro- bzw. Cyano-Akzeptor verwendet. Bei der Synthese immobilisierter Arylboronsäuren wurde einerseits das chromophore Elektronensystem variiert. Andererseits wurden mit einer ausgewählten chromophoren Arylboronsäure verschiedene Funktionalisierungsgrade am Copolymer eingestellt bzw. Copolymere mit unterschiedlichem BMA-Anteil mit einem Funktionalisierungsgrad von 60 % bezogen auf die vorhandenen Diol-Einheiten funktionalisiert. Die optischen Eigenschaften der immobilisierten chromophoren Arylboronsäuren wurden mit der UV/vis-Spektroskopie untersucht. Der Einfluss des Funktionalisierungsgrades sowie des variablen BMA-Anteils auf die thermischen Eigenschaften wurde mittels DSC und TGA studiert. Weiterhin erfolgten an den immobilisierten chromophoren Arylboronsäuren Untersuchungen hinsichtlich des Komplexbildungsverhaltens gegenüber Fluorid-Ionen. Ein besonderes Augenmerk wurde hier auf den Einfluss der BMA-Einheiten auf die Zugänglichkeit der Bor-Atome sowie die Wechselwirkung mit vorhandenen Diol-Einheiten gelegt

Fluorosolvatochromism of furanyl- and thiophenyl-substituted acetophenones

A series of para-substituted acetophenones bearing a furanyl or a thiophenyl moiety show a large Stokes-shift, which is a function of various solvent properties. Photophysical properties such as emission lifetime of the compounds have been determined using time-correlated-single photon counting to secure the intrinsic fluorescence behaviour. The solvent dependent position of the UV/Vis emission band [small nu, Greek, tilde]max,em of the compounds has been measured in 26 various solvents. The influence of the solvent on [small nu, Greek, tilde]max,em is of very complex nature and mathematically analysed by multiple square linear solvation energy (LSE)-correlation analysis using Catalán's four-solvent parameter set. Solvent acidity has a strong influence on the bathochromic shift of 2,5-disubstituted furan derivatives compared to the non-5-substituted furan and thiophene derivatives, which show a contrary behaviour. Therefore, the 5-cyanofuranyl-substituted acetophenone derivative is useful as a probe for measuring environmental properties by fluorescence spectroscopy

Purinergic Signaling on Leukocytes Infiltrating the LPS-Injured Lung

<div><p>Extracellular nucleotides and nucleosides have been implicated as important signaling molecules in the pathogenesis of acute lung injury (ALI). While adenosine is known to inhibit T cell activation, little information is available as to ATP and NAD degrading enzymes, the expression of ATP and adenosine receptors/transporters in different T cell subsets. ALI was induced by challenging mice with intra-tracheal instillation of 60 µl (3 µg/g) LPS. After 3 d and 7 d blood, lung tissue and bronchoalveolar lavage was collected and immune cells were analyzed using flow cytometry. The transcriptional phenotype of T helper cells, cytotoxic and regulatory T cells sorted by FACS was assessed by measuring the expression profile of 28 genes related to purinergic signaling using TaqMan Array Micro Fluidic Cards. Catabolism of ATP, NAD and cAMP by activated CD4⁺ T cells was evaluated by HPLC. CD73 was found to be highly abundant on lymphoid cells with little abundance on myeloid cells, while the opposite was true for CD39. After ALI, the abundance of CD39 and CD73 significantly increased on all T cell subsets derived from lung tissue and bronchoalveolar space. Expression analysis in T cell subsets of the lung revealed ATP (<i>Cd39</i>, <i>Cd73</i>) and NAD (<i>Cd38</i>, <i>Cd157</i>, <i>Cd296</i>, <i>Pc-1</i>) degrading enzymes. However, only transcription of <i>Cd38</i>, <i>Cd39</i>, <i>Cd73</i>, <i>Ent1</i> and <i>A2a receptor</i> was significantly upregulated after ALI in T helper cells. CD4⁺ T cells from injured lung rapidly metabolized extracellular ATP to AMP and adenosine but not NAD or cAMP. These findings show that lung T cells – the dominant cell fraction in the later phase of ALI – exhibit a unique expression pattern of purinergic signaling molecules. Adenosine is formed by T cells at an enhanced rate from ATP but not from NAD and together with upregulated A2a receptor is likely to modulate the healing process after acute lung injury.</p></div

"Imposition et liberté d’exercice du culte », note sous 8 décisions CEDH (depuis CEDH, 29 sept. 2010, n° 8916/05, Les Témoins de Jéhovah c. France) et une Cass. (Com, 15 janv. 2013, n° 12-11.642, Assoc. L’Arche de Marie) in chronique de jurisprudence fiscale

<p>(A+B) The percentage of cells expressing CD73 was high within the T cell subsets but low within the myeloid cell, B cell and NK cell populations. The percentage of CD73 expressing cells tended to be increased in T helper cells after ALI. (C+D) As assessed by means of the MFI CD73 was highly expressed on the different T cell subsets and showed a comparatively low expression on myeloid cells, B cells and NK cells. After LPS installation particular T helper cells, NKC and M&M showed an increased abundance of CD73. Data are mean ± SD (n = 5 mice per group). Statistical significance was assessed by one-way ANOVA with Dunnett's post hoc test. *P<0.05, **P<0.01, ***P<0.0001. Under unstressed conditions CD73 staining of regulatory T cells (IS) and T helper cells (BAL) was detected in only n = 2, thus statistical significance was not assessed. ALI  =  acute lung injury, AM  =  alveolar macrophages, APC  =  antigen-presenting cells, BAL  =  bronchoalveolar lavage, BC  =  B cells, CTC  =  cytotoxic T cells, Gr  =  granulocytes, IS  =  interstitial lung tissue, MFI  =  mean fluorescence intensity, M&M  =  monocytes and macrophages, n.d.  =  not detected, NKC  =  natural killer cells, SD  =  standard deviation, THC  =  T helper cells, Treg  =  regulatory T cells.</p

Dynamic changes of distinct leukocyte subpopulations in lung tissue (IS) and bronchoalveolar lavage (BAL) 3 d and 7 d after intratracheal instillation of LPS.

<p>(A) Representative plots illustrating the gating strategy used to identify different leukocyte subpopulations by flow cytometry. Non-viable immune cells were excluded from the CD45⁺ cells on the basis of a positive DAPI-staining. Viable CD45⁺ cells were then divided into subpopulations using a panel of cell-specific fluorochrome-labeled antibodies. Lymphocytes were gated for CD45R(B220)⁺ cells (B cells) and CD3⁺ cells (T cells). T cells were subdivided into CD4⁺ cells (T helper cells) and CD8⁺ cells (cytotoxic T cells). Myeloid cells were defined as CD11b⁺ cells and further subdivided into CD11c⁺ cells (APCs) and Ly6g⁺ cells (granulocytes) (B) In IS the early phase of inflammation (3 d) was characterized by a transient increase in myeloid immune cell subsets. In the later phase of inflammation (7 d), different T cell subsets were significantly enhanced. (C) Similar to the lung tissue, myeloid immune cell subsets were increased in BAL in the early phase while T cells were enhanced only in the later phase of inflammation. Data are mean ± SD (n = 5 mice per group) Statistical significance was assessed by one-way ANOVA with Dunnett's post hoc test. *P<0.05, **P<0.01, ***P<0.0001. ALI  =  acute lung injury, AM  =  alveolar macrophages, APC  =  antigen-presenting cells, BAL  =  bronchoalveolar lavage, BC  =  B cells, CTC  =  cytotoxic T cells, Gr  =  granulocytes, IS  =  interstitial lung tissue, LPS  =  lipopolysaccharide, M&M  =  monocytes and macrophages, n.d.  =  not detected, NKC  =  natural killer cells, SD  =  standard deviation, THC  =  T helper cells, Treg  =  regulatory T cells.</p

Extracellular degradation of ATP, AMP, NAD, cAMP, ADPR (substrate concentration: 20 µM; 37°C) by activated CD4⁺ T cells isolated from the lung 7 d post induction of ALI.

<p>(A) Rapid ATP degradation to ADP and AMP and slow adenosine formation. (B) AMP only was added as substrate was slowly degraded with concomitant formation of adenosine and inosine. (C) NAD is degraded to ADPR at a moderate rate. (D) CD4⁺ T cells do not degrade ADPR and cAMP. ADO  =  adenosine, ADP  =  adenosine diphosphate, ADPR  =  adenosine diphosphate ribose, ALI  =  acute lung injury, AMP  =  adenosine monophosphate, ATP  =  adenosine triphosphate, cAMP  =  cyclic adenosine monophosphate, INO  =  inosine, NAD  =  nicotinamide adenine dinucleotide.</p