Search results for "Cell Physiological Phenomena"

Advances in the understanding of mast cell function

2008

Mast cells were formerly thought to contribute mainly to, sometimes even, fatal allergic reactions through the release of biologically highly active cytokines, chemokines, lipid mediators, proteases and biogenic amines. This potential harmful response is triggered by crosslinking of cell-bound IgE by the respective allergen. This review updates our current understanding of the emerging roles of mast cells with an emphasis on their relevance in protective host immunity. The activation of mast cells independently of Immunoglobulin E can lead to the initiation of fast inflammatory reactions, which were shown to be life-saving in murine models of bacterial infections. Besides their critical fun…

Structural analyses of a hypothetical minimal metabolism

2007

By integrating data from comparative genomics and large-scale deletion studies, we previously proposed a minimal gene set comprising 206 protein-coding genes. To evaluate the consistency of the metabolism encoded by such a minimal genome, we have carried out a series of computational analyses. Firstly, the topology of the minimal metabolism was compared with that of the reconstructed networks from natural bacterial genomes. Secondly, the robustness of the metabolic network was evaluated by simulated mutagenesis and, finally, the stoichiometric consistency was assessed by automatically deriving the steady-state solutions from the reaction set. The results indicated that the proposed minimal …

Flow cytometry analyses and bioinformatics: interest in new softwares to optimize novel technologies and to favor the emergence of innovative concept…

2007

Heat shock proteins in fibrosis and wound healing: Good or evil?

2014

Heat shock proteins (HSPs) are key regulators of cell homeostasis, and their cytoprotective role has been largely investigated in the last few decades. However, an increasing amount of evidence highlights their deleterious effects on several human pathologies, including cancer, in which they promote tumor cell survival, proliferation and drug resistance. Therefore, HSPs have recently been suggested as therapeutic targets for improving human disease outcomes. Fibrotic diseases and cancer share several properties; both pathologies are characterized by genetic alterations, uncontrolled cell proliferation, altered cell interactions and communication and tissue invasion. The discovery of new HSP…

Microvesicles shed by oligodendroglioma cells and rheumatoid synovial fibroblasts contain aggrecanase activity

2012

Membrane microvesicle shedding is an active process and occurs in viable cells with no signs of apoptosis or necrosis. We report here that microvesicles shed by oligodendroglioma cells contain an ‘aggrecanase’ activity, cleaving aggrecan at sites previously identified as targets for adamalysin metalloproteinases with disintegrin and thrombospondin domains (ADAMTSs). Degradation was inhibited by EDTA, the metalloproteinase inhibitor GM6001 and by tissue inhibitor of metalloproteinases (TIMP)-3, but not by TIMP-1 or TIMP-2. This inhibitor profile indicates that the shed microvesicles contain aggrecanolytic ADAMTS(s) or related TIMP-3-sensitive metalloproteinase(s). The oligodendroglioma cells…

Studies on the subcellular pathophysiology of acute lethal cell injury.

1974

Summary In this paper we have summarized the effects of acute lethal injury on the cell. Such injuries are defined as injuries that result in cell death within a relatively short period of time usually minutes or hours. Following death; the cell undergoes necrosis. Ultrastructural and biochemical methods are needed to study pathophysiology. The cell passes through a series of stages numbered 1 through 7. Stages 1 through 4 are reversible while 5 through 7 are irreversible. Injuries resulting in acute cell death and necrosis include direct damage to the cell membrane, for example by antibody and complement or non-penetrating mercurials or interference with mitochondrial energy supply as in i…

Splitting the dynamics of large biochemical interaction networks

2003

This article is inscribed in the general motivation of understanding the dynamics on biochemical networks including metabolic and genetic interactions. Our approach is continuous modeling by differential equations. We address the problem of the huge size of those systems. We present a mathematical tool for reducing the size of the model, master-slave synchronization, and fit it to the biochemical context.

Chromatin modifiers and recombination factors promote a telomere fold-back structure, that is lost during replicative senescence.

2020

Telomeres have the ability to adopt a lariat conformation and hence, engage in long and short distance intra-chromosome interactions. Budding yeast telomeres were proposed to fold back into subtelomeric regions, but a robust assay to quantitatively characterize this structure has been lacking. Therefore, it is not well understood how the interactions between telomeres and non-telomeric regions are established and regulated. We employ a telomere chromosome conformation capture (Telo-3C) approach to directly analyze telomere folding and its maintenance in S. cerevisiae. We identify the histone modifiers Sir2, Sin3 and Set2 as critical regulators for telomere folding, which suggests that a dis…

RNA memory model: a RNA-mediated transcriptional activation mechanism involved in cell identity.

2010

Position-effect variegation (PEV) was discovered in Drosophila melanogaster in 1930 in a study of X-ray-induced chromosomal rearrangements. If a rearrangement places euchromatic genes adjacent to a region of centromeric heterochromatin, it gives a variegated phenotype that results from the random inactivation of genes by heterochromatin spreading from the breakpoint. After the establishment, the inactivation is henceforth clonally inherited. The vast majority of these modifiers were originally isolated in Drosophila as dominant mutations that suppressed or enhanced the variegation caused by a variegating white allele called white-mottled 4 (wm4). A large number of modifier genes alter PEV p…