| 1. |
- Bergmann, Simone, et al.
(författare)
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Exploitation of Host Signal Transduction Pathways Induced by Streptococcus pneumoniae
- 2015
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Ingår i: Streptococcus Pneumoniae : Molecular Mechanisms of Host-Pathogen Interactions - Molecular Mechanisms of Host-Pathogen Interactions. - 9780124105300 - 9780124114531 ; , s. 347-362
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Bokkapitel (refereegranskat)abstract
- The induction of host signal transduction cascades by bacterial pathogens contributes directly to their virulence. In addition to the pore-forming cytolysin pneumolysin, several surface-exposed proteins of Streptococcus pneumoniae are also potent modulators of complex host signaling pathways. These pneumococcal surface proteins either directly mediate adhesion of pneumococci to specific cell surface receptors or recruit extracellular matrix or serum components as molecular bridges for binding to cellular receptors. In turn, adhesion triggers and subverts host signal transduction cascades to promote pneumococcal translocation across tissue barriers and dissemination within host tissues. This chapter summarizes the current knowledge of how pneumolysin and major adhesins manipulate host signaling pathways. The chapter will provide a structured overview of the signaling profiles induced by pneumococci, focusing on the receptors required and comparing the key signaling molecules and intracellular responses involved.
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| 2. |
- Jagau, Hilger, et al.
(författare)
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Pneumococcus Infection of Primary Human Endothelial Cells in Constant Flow
- 2019
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Ingår i: Journal of visualized experiments : JoVE. - : MyJove Corporation. - 1940-087X. ; :152
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Tidskriftsartikel (refereegranskat)abstract
- Interaction of Streptococcus pneumoniae with the surface of endothelial cells is mediated in blood flow via mechanosensitive proteins such as the Von Willebrand Factor (VWF). This glycoprotein changes its molecular conformation in response to shear stress, thereby exposing binding sites for a broad spectrum of host-ligand interactions. In general, culturing of primary endothelial cells under a defined shear flow is known to promote the specific cellular differentiation and the formation of a stable and tightly linked endothelial layer resembling the physiology of the inner lining of a blood vessel. Thus, the functional analysis of interactions between bacterial pathogens and the host vasculature involving mechanosensitive proteins requires the establishment of pump systems that can simulate the physiological flow forces known to affect the surface of vascular cells. The microfluidic device used in this study enables a continuous and pulseless recirculation of fluids with a defined flow rate. The computer-controlled air-pressure pump system applies a defined shear stress on endothelial cell surfaces by generating a continuous, unidirectional, and controlled medium flow. Morphological changes of the cells and bacterial attachment can be microscopically monitored and quantified in the flow by using special channel slides that are designed for microscopic visualization. In contrast to static cell culture infection, which in general requires a sample fixation prior to immune labeling and microscopic analyses, the microfluidic slides enable both the fluorescence-based detection of proteins, bacteria, and cellular components after sample fixation; serial immunofluorescence staining; and direct fluorescence-based detection in real time. In combination with fluorescent bacteria and specific fluorescence-labeled antibodies, this infection procedure provides an efficient multiple component visualization system for a huge spectrum of scientific applications related to vascular processes.
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| 3. |
- Sellberg, Jonas A., et al.
(författare)
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X-ray emission spectroscopy of bulk liquid water in no-man's land
- 2015
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 142:4
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Tidskriftsartikel (refereegranskat)abstract
- The structure of bulk liquid water was recently probed by x-ray scattering below the temperature limit of homogeneous nucleation (T-H) of similar to 232 K [J. A. Sellberg et al., Nature 510, 381-384 (2014)]. Here, we utilize a similar approach to study the structure of bulk liquid water below T-H using oxygen K-edge x-ray emission spectroscopy (XES). Based on previous XES experiments [T. Tokushima et al., Chem. Phys. Lett. 460, 387-400 (2008)] at higher temperatures, we expected the ratio of the 1b(1)' and 1b(1) peaks associated with the lone-pair orbital in water to change strongly upon deep supercooling as the coordination of the hydrogen (H-) bonds becomes tetrahedral. In contrast, we observed only minor changes in the lone-pair spectral region, challenging an interpretation in terms of two interconverting species. A number of alternative hypotheses to explain the results are put forward and discussed. Although the spectra can be explained by various contributions from these hypotheses, we here emphasize the interpretation that the line shape of each component changes dramatically when approaching lower temperatures, where, in particular, the peak assigned to the proposed disordered component would become more symmetrical as vibrational interference becomes more important.
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| 4. |
- Ståhl, Patrik, Dr., et al.
(författare)
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Visualization and analysis of gene expression in tissue sections by spatial transcriptomics
- 2016
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Ingår i: Science. - : AMER ASSOC ADVANCEMENT SCIENCE. - 0036-8075 .- 1095-9203. ; 353:6294, s. 78-82
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Tidskriftsartikel (refereegranskat)abstract
- Analysis of the pattern of proteins or messenger RNAs (mRNAs) in histological tissue sections is a cornerstone in biomedical research and diagnostics. This typically involves the visualization of a few proteins or expressed genes at a time. We have devised a strategy, which we call "spatial transcriptomics," that allows visualization and quantitative analysis of the transcriptome with spatial resolution in individual tissue sections. By positioning histological sections on arrayed reverse transcription primers with unique positional barcodes, we demonstrate high-quality RNA-sequencing data with maintained two-dimensional positional information from the mouse brain and human breast cancer. Spatial transcriptomics provides quantitative gene expression data and visualization of the distribution of mRNAs within tissue sections and enables novel types of bioinformatics analyses, valuable in research and diagnostics.
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