Search results for "Acellular"

Characterization of a putative extracellular matrix protein from the beetle Tenebrio molitor: hormonal regulation during metamorphosis.

2004

0949-944X (Print) Journal Article Research Support, Non-U.S. Gov't; We used differential display to isolate epidermis cDNAs corresponding to juvenile-hormone analog-regulated mRNA from the beetle Tenebrio molitor. One of them encodes a putative extracellular matrix (ECM) protein, named Tenebrin. Indeed, the deduced protein sequence contains ECM typical features like the presence of a signal peptide, internal repeats, a RGD tripeptide sequence motif known to bind integrins and von Willebrand factor type c domains involved in protein-protein interactions. Northern blot analysis reveals a single transcript of about 11 kb with an expression pattern correlated to 20-hydroxyecdysone fluctuations …

Growth-dependent release of carbohydrate metabolism-related and antioxidant enzymes from Staphylococcus aureus strain 6 as determined by proteomic an…

2011

Proteins released into the culture medium by Staphylococcus aureus (S. aureus) strain 6 were determined at the end of the exponential growth phase (4.5 h). Eleven proteins were identified by liquid chromatography coupled with mass spectrometry. Three proteins were predicted to have signal peptides indicating their extracellular localization. The other proteins were presumably located in the cytoplasm of the bacteria. Five out of the 11 proteins were involved in carbo- hydrate metabolism. Other intracellular proteins of S. aureus were not detected in the culture medium. This indicates that the release of these 11 proteins was specific and that unspecific protein release due to damaged or dyi…

Effects of low frequency electric fields on synaptic integration in hippocampal CA1 pyramidal neurons: implications for power line emissions

2014

The possible cognitive effects of low frequency external electric fields, such as those generated by power lines, are poorly understood. Their functional consequences for mechanisms at the single neuron level are very difficult to study and identify experimentally, especially in vivo. The major open problem is that experimental investigations on humans have given inconsistent or contradictory results, making it difficult to estimate the possible effects of external low frequency electric fields on cognitive functions. Here we investigate this issue with a realistic model of hippocampal CA1 pyramidal neurons. The model suggests how and why external electric fields, with environmentally obser…

Complexity analysis of experimental cardiac arrhythmia

2014

International audience; To study the cardiac arrhythmia, an in vitro experimental model and Multielectrodes Array (MEA) are used. This platform serves as an intermediary of the electrical activities of cardiac cells and the signal processing / dynamics analysis. Through it the extracellular potential of cardiac cells is acquired, allowing a real-time monitoring / analyzing. Since MEA has 60 electrodes / channels dispatched in a rectangular region, it allows real-time monitoring and signal acquisition on multiple sites. The in vitro experimental model (cardiomyocytes cultures from new-born rats' heart) is directly prepared on the MEA. This carefully prepared culture has similar parameters as…

Extracellular vesicles from neural stem cells transfer the IFN-gamma/IFNGR1 complex to activate Stat1-dependent signalling in target cells

2014

Enzyme-responsive intracellular-controlled release using silica mesoporous nanoparticles capped with ε-poly-L-lysine.

2014

The synthesis and characterization of two new capped silica mesoporous nanoparticles for controlled delivery purposes are described. Capped hybrid systems consist of MCM-41 nanoparticles functionalized on the outer surface with polymer epsilon-poly-L-lysine by two different anchoring strategies. In both cases, nanoparticles were loaded with model dye molecule [Ru(bipy)(3)](2+). An anchoring strategy involved the random formation of urea bonds by the treatment of propyl isocyanate-functionalized MCM-41 nanoparticles with the lysine amino groups located on the epsilon-poly-L-lysine backbone (solid Ru-rLys-S1). The second strategy involved a specific attachment through the carboxyl terminus of…

Matrix metalloproteinases 2 and 9, and extracellular matrix in Kaposi's sarcoma

2010

Matrix metalloproteinases (MMPs) are associated with Kaposi's sarcoma (KS) tumorigenesis and may contribute to the mechanism of KS invasive growth. To date, only a few MMPs have been studied in KS lesions, and exactly which MMPs are involved in KS development and progression remains unanswered. However, MMPs 2 and 9 have been associated with different phases of angiogenesis, but their role in the proteolytic modification of the extracellular matrix has not been investigated. The results of this study confirm that MMPs, specifically MMP-2 and MMP-9, can contribute to angiogenesis by disrupting the vessel basement membrane and other extracellular matrix barriers, and enabling endothelial cell…

RNA marker modifications reveal the necessity for rigorous preparation protocols to avoid artifacts in epitranscriptomic analysis

2021

Abstract The accurate definition of an epitranscriptome is endangered by artefacts resulting from RNA degradation after cell death, a ubiquitous yet little investigated process. By tracing RNA marker modifications through tissue preparation protocols, we identified a major blind spot from daily lab routine, that has massive impact on modification analysis in small RNAs. In particular, m6,6A and Am as co-varying rRNA marker modifications, appeared in small RNA fractions following rRNA degradation in vitro and in cellulo. Analysing mouse tissue at different time points post mortem, we tracked the progress of intracellular RNA degradation after cell death, and found it reflected in RNA modific…

AP-1 Transcription Factor Serves as a Molecular Switch between Chlamydia pneumoniae Replication and Persistence

2015

ABSTRACT Chlamydia pneumoniae is a Gram-negative bacterium that causes acute or chronic respiratory infections. As obligate intracellular pathogens, chlamydiae efficiently manipulate host cell processes to ensure their intracellular development. Here we focused on the interaction of chlamydiae with the host cell transcription factor activator protein 1 (AP-1) and its consequence on chlamydial development. During Chlamydia pneumoniae infection, the expression and activity of AP-1 family proteins c-Jun, c-Fos, and ATF-2 were regulated in a time- and dose-dependent manner. We observed that the c-Jun protein and its phosphorylation level significantly increased during C. pneumoniae development.…

Enhancing Gene Knockdown Efficiencies by Comparing siRNA-Loaded Cationic Nanogel Particles of Different Sizes

2015

lt;pgt;In order to silence the expression levels of pathogenic genes, small interfering RNA (siRNA) requires a nano-sized carrier for its safe and stable delivery into cells. In this research highlight, we focus on well-defined cationic nanohydrogel particles developed in our group for such purposes. To investigate the nanogels’ mechanism for enhanced knockdown efficiencies, we recently synthesized two sets of particles with similar material composition and siRNA-loading characteristics, but – according to the manufacturing process – of different sizes. Within this study, 100-nm-sized nanogel particles loaded with siRNA accumulated inside the lysosomes already after 4 h and could not induce…