Search results for "Animal Structures"
showing 10 items of 876 documents
CD83+ human dendritic cells transfected with tumor peptide cDNA by electroporation induce specific T-cell responses: A potential tool for gene immuno…
2000
Dendritic cells (DC) are the most potent immunostimulatory cells, with the capacity to induce primary T-cell responses. Functional autologous DC can be generated from fetal calf serum-free peripheral blood mononuclear cells in the presence of interleukin-4 and granulocyte-macrophage colony-stimulating factor and are stimulated with a defined cytokine cocktail for terminal maturation. We were able to establish a nonviral transfection protocol for these DC by electroporation. Using enhanced green fluorescent protein as a reporter gene, we achieved transfection efficiencies of up to 10%. FACScan analyses revealed a stable phenotype, and the expression of major histocompatibility complex class …
cDNA sequences of the authentic keratins 8 and 18 in zebrafish
2003
From the zebrafish Danio rerio, we have cDNA cloned and sequenced a novel type II and a novel type I keratin, termed DreK8 and DreK18, respectively. We identified DreK8/18 as the true orthologs of the human keratin pair K8/18 as follows: (i) MALDI-MS assignment to the biochemically identified K8 and K18 candidates that are co-expressed in simple epithelia and absent in epidermal keratinocytes; (ii) multiple sequence alignments and phylogenetic tree analysis, showing that DreK8, within the phylogenetic tree of type II keratins, forms a highly bootstrap-supported branch together with K8 from goldfish and rainbow trout, whereas DreK18, within the phylogenetic tree of type I keratins, groups wi…
Heat-Shock Proteins in Sea Urchin Embryos
1982
The production of heat-shock proteins in sea urchin embryos is accompanied by the appearance at the polysomal level of their relative mRNAs, as shown by their translation in a cell-free system; thus suggesting that the regulation of their production occurs at a transcriptional level. The mechanism for the inhibition of the bulk protein synthesis and for its reversal on the other hand should be looked for at a posttranscriptional level, since both these phenomena occur also in the presence of actinomycin D. The heat-shock proteins produced as early as at the mesenchyme blastula stage persist within the embryo at least till the pluteus stage.
Apoptosis: focus on sea urchin development
2009
It has been proposed that the apoptosis is an essential requirement for the evolution of all animals, in fact the apoptotic program is highly conserved from nematodes to mammals. Throughout development, apoptosis is employed by multicellular organisms to eliminate damaged or unnecessary cells. Here, we will discuss both developmental programmed cell death (PCD) under normal conditions and stress induced apoptosis, in sea urchin embryos. Sea urchin represent an excellent model system for studying embryogenesis and cellular processes involved in metamorphosis. PCD plays an essential role in sculpting and remodelling the embryos and larvae undergoing metamorphosis. Moreover, this marine organi…
Deleting Full Length Titin Versus the Titin M-Band Region Leads to Differential Mechanosignaling and Cardiac Phenotypes
2019
Background: Titin is a giant elastic protein that spans the half-sarcomere from Z-disk to M-band. It acts as a molecular spring and mechanosensor and has been linked to striated muscle disease. The pathways that govern titin-dependent cardiac growth and contribute to disease are diverse and difficult to dissect. Methods: To study titin deficiency versus dysfunction, the authors generated and compared striated muscle specific knockouts (KOs) with progressive postnatal loss of the complete titin protein by removing exon 2 (E2-KO) or an M-band truncation that eliminates proper sarcomeric integration, but retains all other functional domains (M-band exon 1/2 [M1/2]-KO). The authors evaluated c…
The ultrastructure of articular cartilage of the chicken's knee joint
1993
The articular cartilage and synovial membrane of immature and mature chicken knee joints were studied by light, scanning and transmission microscopy. The findings differed from human articular cartilage and we conclude that the chicken knee joint is not suitable as a model for human joint degeneration.
The Odyssey of Hsp60 from Tumor Cells to Other Destinations Includes Plasma Membrane-Associated Stages and Golgi and Exosomal Protein-Trafficking Mod…
2012
BACKGROUND: In a previous work we showed for the first time that human tumor cells secrete Hsp60 via exosomes, which are considered immunologically active microvesicles involved in tumor progression. This finding raised questions concerning the route followed by Hsp60 to reach the exosomes, its location in them, and whether Hsp60 can be secreted also via other mechanisms, e.g., by the Golgi. We addressed these issues in the work presented here. PRINCIPAL FINDINGS: We found that Hsp60 localizes in the tumor cell plasma membrane, is associated with lipid rafts, and ends up in the exosomal membrane. We also found evidence that Hsp60 localizes in the Golgi apparatus and its secretion is prevent…
Timing of identity: spatiotemporal regulation of hunchback in neuroblast lineages of Drosophila by Seven-up and Prospero.
2006
Neural stem cells often generate different cell types in a fixed birth order as a result of temporal specification of the progenitors. In Drosophila, the first temporal identity of most neural stem cells(neuroblasts) in the embryonic ventral nerve cord is specified by the transient expression of the transcription factor Hunchback. When reaching the next temporal identity, this expression is switched off in the neuroblasts by seven up (svp) in a mitosis-dependent manner, but is maintained in their progeny (ganglion mother cells). We show that svpmRNA is already expressed in the neuroblasts before this division. After mitosis, Svp protein accumulates in both cells, but the downregulation of h…
Generation of cell diversity and segmental pattern in the embryonic central nervous system of Drosophila.
2005
Development of the central nervous system (CNS) involves the transformation of a two-dimensional epithelial sheet of uniform ectodermal cells, the neuroectoderm, into a highly complex three-dimensional structure consisting of a huge variety of different neural cell types. Characteristic numbers of each cell type become arranged in reproducible spatial patterns, which is a prerequisite for the establishment of specific functional contacts. The fruitfly Drosophila is a suitable model to approach the mechanisms controlling the generation of cell diversity and pattern in the developing CNS, as it allows linking of gene function to individually identifiable cells. This review addresses aspects o…
Tenectin, a novel extracellular matrix protein expressed during Drosophila melanogaster embryonic development
2006
1567-133X (Print) Journal Article Research Support, Non-U.S. Gov't; During Drosophila embryonic development, various morphogenetic processes require the remodeling of the extracellular matrix. In a previous study, we have identified and characterized a cDNA encoding a novel putative extracellular matrix protein named tenebrin, in the beetle Tenebrio molitor. Here, we examine the expression of the Drosophila ortholog, referred to as Tenectin (Tnc), during embryonic development. Tnc is expressed in the majority of tissues of neuroectodermic origin such as hindgut, foregut, tracheal system, anal plate, and CNS. In the CNS, the Tnc transcript is restricted to a few cells, whereas the protein is…