Search results for "Apoptosi"
showing 10 items of 1846 documents
Studies on heat shock proteins in sea urchin development
1999
Work on stress proteins in sea urchin embryos carried out over the last 20 years is reviewed and the following major results are described. Entire sea urchin embryos, if subjected to a rise in temperature at any postblastular stage undergo a wave of heat shock protein (hsp) synthesis and survive. If subjected to the same rise between fertilization and blastula formation, they are not yet able to synthesize hsp and die. Four clones coding for the major hsp, hsp70, have been isolated and sequenced; evidence for the existence of a heat shock factor has been provided, and a mechanism for the developmental regulation of hsp synthesis discussed. Intra- embryonic and intracellular hsp location has…
Sea urchin embryos as an in vivo model for the assessment of manganese toxicity: developmental and stress response effects.
2009
In the marine environment increasing concentrations of bio-available compounds often result from anthropogenic activities. Among metal ions, manganese represents a new emergent factor in environmental contamination. Here, we studied the effects of manganese on Paracentrotus lividus sea urchin embryos using biological and biochemical approaches for the analysis of impact on development, tissue accumulation and stress markers. Embryos were continuously exposed from fertilization to manganese at concentrations ranging from 1.0 to 61.6 mg l(-1), monitored for developmental abnormalities at 48 h after fertilization, and used for atomic spectrometric analysis at various times from 6 to 72 h. We f…
Toxicity of vanadium during development of sea urchin embryos: bioaccumulation, calcium depletion, ERK modulation and cell-selective apoptosis
2022
Vanadium toxicology is a topic of considerable importance as this metal is widely used in industrial and biomedical fields. However, it represents a potential emerging environmental pollutant because wastewater treatment plants do not adequately remove metal compounds that are subsequently released into the environment. Vanadium applications are limited due to its toxicity, so it is urgent to define this aspect. This metal is associated with sea urchin embryo toxicity as it perturbs embryogenesis and skeletogenesis, triggering several stress responses. Here we investigated its bioaccumulation and the correlation with cellular and molecular developmental pathways. We used cytotoxic concentra…
Sea urchin embryos as a model system for studying autophagy induced by cadmium stress
2011
It is well known that sea urchin embryos are able to activate different defense strategies against stress. We previously demonstrated that cadmium treatment triggers the accumulation of metal in embryonic cells and the activation of defense systems depending on concentration and exposure time, through the synthesis of heat shock proteins and/or the initiation of apoptosis. Here we show that Paracentrotus lividus embryos exposed to Cd adopt autophagy as an additional stratagem to safeguard the developmental program. At present, there are no data focusing on the role of this process in embryo development of marine organisms. In this paper we utilized different techniques to detect autophagy i…
The p21-activated kinase Mbt is a component of the apical protein complex in central brain neuroblasts and controls cell proliferation
2013
The final size of the central nervous system is determined by precisely controlled generation, proliferation and death of neural stem cells. We show here that the Drosophila PAK protein Mushroom bodies tiny (Mbt) is expressed in central brain progenitor cells (neuroblasts) and becomes enriched to the apical cortex of neuroblasts in a cell cycle- and Cdc42-dependent manner. Using mushroom body neuroblasts as a model system, we demonstrate that in the absence of Mbt function, neuroblasts and their progeny are correctly specified and are able to generate different neuron subclasses as in the wild type, but are impaired in their proliferation activity throughout development. In general, loss of…
The RNA-binding protein ELAV regulates Hox RNA processing, expression and function within the Drosophila nervous system
2014
The regulated head-to-tail expression of Hox genes provides a coordinate system for the activation of specific programmes of cell differentiation according to axial level. Recent work indicates that Hox expression can be regulated via RNA processing but the underlying mechanisms and biological significance of this form of regulation remain poorly understood. Here we explore these issues within the developing Drosophila central nervous system (CNS). We show that the pan-neural RNA-binding protein (RBP) ELAV (Hu antigen) regulates the RNA processing patterns of the Hox gene Ultrabithorax (Ubx) within the embryonic CNS. Using a combination of biochemical, genetic and imaging approaches we demo…
Cadmium induces an apoptotic response in sea urchin embryos.
2007
Cadmium is a heavy metal toxic for living organisms even at low concentrations. It does not have any biological role, and since it is a permanent metal ion, it is accumulated by many organisms. In the present paper we have studied the apoptotic effects of continuous exposure to subacute/sublethal cadmium concentrations on a model system: Paracentrotus lividus embryos. We demonstrated, by atomic absorption spectrometry, that the intracellular amount of metal increased during exposure time. We found, using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay, that long treatments with cadmium triggered a severe DNA fragmentation. We demonstrated, by immunocytochemistry …
An organizing region in metamorphosing hydrozoan planula larvae--stimulation of axis formation in both larval and in adult tissue.
2010
A novel wingless gene was isolated from the marine colonial hydroid Hydractinia echinata. Alignments and Bayesian inference analysis clearly assign the gene to the Wnt5A group. In line with data found for the brachyury ortholog of Hydractinia, He-wnt5A is expressed during metamorphosis in the posterior tip of the spindle-shaped planula larva, suggesting that the tip functions as a putative organizer during metamorphosis. Additionally, the outermost cells of the posterior tip are omitted from apoptosis during metamorphosis. In order to investigate this putative organizer function, we transplanted the posterior tip of metamorphosing animals into non-induced larvae and into primary polyps 24 h…
Apoptosis of oligodendrocytes via Fas and TNF-R1 is a key event in the induction of experimental autoimmune encephalomyelitis.
2005
Abstract In experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis, immunization with myelin Ags leads to demyelination and paralysis. To investigate which molecules are crucial for the pathogenesis of EAE, we specifically assessed the roles of the death receptors Fas and TNF-R1. Mice lacking Fas expression in oligodendrocytes (ODCs) were generated and crossed to TNF-R1-deficient mice. To achieve specific deletion of a loxP-flanked fas allele in ODCs, we generated a new insertion transgene, expressing the Cre recombinase specifically in ODCs. Fas inactivation alone as well as the complete absence of TNF-R1 protected mice partially from EAE induced by the imm…
Derivatives of Erythropoietin That Are Tissue Protective But Not Erythropoietic
2004
Erythropoietin (EPO) is both hematopoietic and tissue protective, putatively through interaction with different receptors. We generated receptor subtype–selective ligands allowing the separation of EPO's bioactivities at the cellular level and in animals. Carbamylated EPO (CEPO) or certain EPO mutants did not bind to the classical EPO receptor (EPOR) and did not show any hematopoietic activity in human cell signaling assays or upon chronic dosing in different animal species. Nevertheless, CEPO and various nonhematopoietic mutants were cytoprotective in vitro and conferred neuroprotection against stroke, spinal cord compression, diabetic neuropathy, and experimental autoimmune encephalomyeli…