Search results for "Interactions"
showing 10 items of 1963 documents
Lipid Bilayer Interactions of Peptidic Supramolecular Polymers and Their Impact on Membrane Permeability and Stability.
2020
The synthesis and physicochemical characterization of supramolecular polymers with tunable assembly profiles offer exciting opportunities, involving the development of new biomedical carriers. Because synthetic nanocarriers aim to transport substances across or toward cellular membranes, we evaluated the interactions of amphiphilic peptide-based supramolecular polymers with lipid bilayers. Here, we focused on nanorod-like supramolecular polymers, obtained from two C3-symmetric dendritic peptide amphiphiles with alternating Phe/His sequences, equipped with a peripheral tetraethylene glycol dendron (C3-PH) or charged ethylenediamine end groups (C3-PH+). Triggered by pH changes, these amphiphi…
Concepts to Reveal Parvovirus–Nucleus Interactions
2021
Parvoviruses are small single-stranded (ss) DNA viruses, which replicate in the nucleoplasm and affect both the structure and function of the nucleus. The nuclear stage of the parvovirus life cycle starts at the nuclear entry of incoming capsids and culminates in the successful passage of progeny capsids out of the nucleus. In this review, we will present past, current, and future microscopy and biochemical techniques and demonstrate their potential in revealing the dynamics and molecular interactions in the intranuclear processes of parvovirus infection. In particular, a number of advanced techniques will be presented for the detection of infection-induced changes, such as DNA modification…
Galantamine modulates nicotinic receptor and blocks Aβ-enhanced glutamate toxicity
2004
Galantamine is a plant alkaloid that is used in the treatment of Alzheimer's disease. We have studied the effects of galantamine on beta-amyloid-enhanced glutamate toxicity using primary rat cultured cortical neurons. Nicotine and galantamine alone, and in combination, protected neurons against this neurotoxicity. The protection was not blocked by alpha4beta2 nicotinic acetylcholine receptor (nAChR) antagonists, but was partially blocked by alpha7 nAChR antagonists. Galantamine induced phosphorylation of Akt, an effector of phosphatidylinositol 3-kinase (PI3K), while PI3K inhibitors blocked the protective effect and Akt phosphorylation. The antibody FK1, which selectively blocks the alloste…
Gènes fongiques liés au calcium impliqués dans la mycorhize à arbuscules
2012
Fluctuations in intracellular (Ca2+) calcium levels generate signaling events and regulate different cellular processes. Whilst the implication of Ca2+ in plant cell responses during arbuscular mycorrhiza (AM) interactions is well documented, nothing is known about the regulation or role of this secondary meesenger in the fungal symbiont. The molecular basis of fungal calcium homeostasis in the AM symbiosis was analyzed by investigating the expression of Ca2+-related fungal genes. In a first study, G. mosseae genes putatively encoding a MAP3k-like protein kinase (Gm2) and a P-type ATPase (Gm152) were investigated. Both Ca2+-related genes were up-regulated by A. sinicum root exudates, sugges…
Nanoscale Mapping of the Physical Surface Properties of Human Buccal Cells and Changes Induced by Saliva
2019
International audience; The mucosal pellicle, also called salivary pellicle, is a thin biological layer made of salivary and epithelial constituents, lining oral mucosae. It contributes to their protection against microbiological, chemical, or mechanical insults. Pellicle formation depends on the cells’ surface properties, and in turn the pellicle deeply modifies such properties. It has been reported that the expression of the transmembrane mucin MUC1 in oral epithelial cells improves the formation of the mucosal pellicle. Here, we describe an approach combining classical and functionalized tip atomic force microscopy and scanning microwave microscopy to characterize how MUC1 induces change…
The emergence of Vibrio pathogens in Europe : ecology, evolution, and pathogenesis (Paris, 11-12th March 2015)
2015
Global change has caused a worldwide increase in reports of Vibrio-associated diseases with ecosystem-wide impacts on humans and marine animals. In Europe, higher prevalence of human infections followed regional climatic trends with outbreaks occurring during episodes of unusually warm weather. Similar patterns were also observed in Vibrio-associated diseases affecting marine organisms such as fish, bivalves and corals. Basic knowledge is still lacking on the ecology and evolutionary biology of these bacteria as well as on their virulence mechanisms. Current limitations in experimental systems to study infection and the lack of diagnostic tools still prevent a better understanding of Vibrio…
The transcription factor Interferon Regulatory Factor 4 is required for the generation of protective effector CD8 + T cells
2013
Robust cytotoxic CD8 + T-cell response is important for immunity to intracellular pathogens. Here, we show that the transcription factor IFN Regulatory Factor 4 (IRF4) is crucial for the protective CD8 + T-cell response to the intracellular bacterium Listeria monocytogenes . IRF4-deficient ( Irf4 −/− ) mice could not clear L. monocytogenes infection and generated decreased numbers of L. monocytogenes -specific CD8 + T cells with impaired effector phenotype and function. Transfer of wild-type CD8 + T cells into Irf4 −/− mice improved bacterial clearance, suggesting an intrinsic defect of CD8 + T cells in Irf4 −/− mice. Following transfer into wild-type recipients, Irf4 −/− CD8 + T cells bec…
Cellular interactions ofCandida albicanswith human oral epithelial cells and enterocytes
2010
The human pathogenic fungus Candida albicans can cause systemic infections by invading epithelial barriers to gain access to the bloodstream. One of the main reservoirs of C. albicans is the gastrointestinal tract and systemic infections predominantly originate from this niche. In this study, we used scanning electron and fluorescence microscopy, adhesion, invasion and damage assays, fungal mutants and a set of fungal and host cell inhibitors to investigate the interactions of C. albicans with oral epithelial cells and enterocytes. Our data demonstrate that adhesion, invasion and damage by C. albicans depend not only on fungal morphology and activity, but also on the epithelial cell type an…
Hemin induces germ tube formation in Candida albicans.
1997
Hemin induced germination of Candida albicans blastoconidia when cells grown up to the early exponential phase were shifted from 28 to 37 degrees C (70 to 75% of cells exhibited germ tubes). N-Acetyl-D-glucosamine (GlcNAc), another inducer of myceliation in this fungus, caused a similar effect. The combination of hemin and GlcNAc resulted in a higher percentage (95%) of blastoconidial germination. These results suggest that in addition to temperature, hemin levels and carbon source may coordinately regulate the expression of subsets of genes involved in the yeast-to-mycelium transition in C. albicans.
Gray Matter NG2 Cells Display Multiple Ca2+-Signaling Pathways and Highly Motile Processes
2011
NG2 cells, the fourth type of glia in the mammalian CNS, receive synaptic input from neurons. The function of this innervation is unknown yet. Postsynaptic changes in intracellular Ca(2+)-concentration ([Ca(2+)](i)) might be a possible consequence. We employed transgenic mice with fluorescently labeled NG2 cells to address this issue. To identify Ca(2+)-signaling pathways we combined patch-clamp recordings, Ca(2+)-imaging, mRNA-transcript analysis and focal pressure-application of various substances to identified NG2-cells in acute hippocampal slices. We show that activation of voltage-gated Ca(2+)-channels, Ca(2+)-permeable AMPA-receptors, and group I metabotropic glutamate-receptors provo…