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Developing Zebrafish (developing + zebrafish)

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Life Sciences100%

Terms modified by Developing Zebrafish

  • developing zebrafish brain
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    Selected Abstracts

    Two neuron clusters in the stem of postembryonic zebrafish brain specifically express relaxin -3 gene: First evidence of nucleus incertus in fish

    DEVELOPMENTAL DYNAMICS, Issue 12 2008
    Aldo Donizetti
    Abstract We examined the spatial expression of the relaxin -3 gene in the developing zebrafish brain, one of the vertebrate model systems in which this gene has been identified. Until the pharyngula stage, the gene is expressed diffusely in the brain, where, starting at about 40 hpf, the transcripts appear restricted in a midbrain cell cluster of the periaqueductal gray. Later, at 72 hpf, the transcripts are still evident in that cluster and distributed in a larger cell number; at this stage, the gene is also expressed posteriorly, in a smaller cell group that, as we report for the first time, could be homologous to mammalian nucleus incertus. The gene expression persists in both cell clusters at 96 hpf. This pattern indicates both conserved and divergent expression features of the relaxin -3 gene among developing zebrafish and rat brains, where only scattered cells express the gene in the periaqueductal gray. Developmental Dynamics 237:3864,3869, 2008. © 2008 Wiley-Liss, Inc. [source]

    Six cadm/synCAM genes are expressed in the nervous system of developing zebrafish

    DEVELOPMENTAL DYNAMICS, Issue 1 2008
    Thomas Pietri
    Abstract The Cadm (cell adhesion molecule) family of cell adhesion molecules (also known as IGSF4, SynCAM, Necl and TSLC) has been implicated in a multitude of physiological and pathological processes, such as spermatogenesis, synapse formation and lung cancer. The precise mechanisms by which these adhesion molecules mediate these diverse functions remain unknown. To investigate mechanisms of action of these molecules during development, we have identified zebrafish orthologs of Cadm family members and have examined their expression patterns during development and in the adult. Zebrafish possess six cadm genes. Sequence comparisons and phylogenetic analysis suggest that four of the zebrafish cadm genes represent duplicates of two tetrapod Cadm genes, whereas the other two cadm genes are single orthologs of tetrapod Cadm genes. All six zebrafish cadms are expressed throughout the nervous system both during development and in the adult. The spatial and temporal patterns of expression suggest multiple roles for Cadms during nervous system development. Developmental Dynamics 237:233,246, 2008. © 2007 Wiley-Liss, Inc. [source]

    cadherin-6 Message expression in the nervous system of developing zebrafish

    DEVELOPMENTAL DYNAMICS, Issue 1 2006
    Qin Liu
    Abstract Cadherins are cell surface adhesion molecules that play important roles in development of a variety of tissues including the nervous system. In this study, we analyzed expression pattern of cadherin-6, a member of the type II cadherin subfamily, in the embryonic zebrafish nervous system using in situ hybridization methods. cadherin-6 message is first expressed by the neural keel, then by restricted regions in the brain and spinal cord. cadherin-6 expression in the brain transiently delineates specific brain regions. In the peripheral nervous system, cadherin-6 message is expressed by the neurogenic placodes and the dorsal root ganglia. As development proceeds, cadherin-6 expression domain and/or expression levels increased in the embryonic nervous system. Our results show that cadherin-6 expression in the zebrafish developing nervous system is both spatially and temporally regulated, implicating a role for cadherin-6 in the formation of these nervous structures. Developmental Dynamics 235:272,278, 2006. © 2005 Wiley-Liss, Inc. [source]

    Arachidonic acid as a retrograde signal controlling growth and dynamics of retinotectal arbors

    DEVELOPMENTAL NEUROBIOLOGY, Issue 1 2008
    B.H. Leu
    Abstract In the developing visual system, correlated presynaptic activity between neighboring retinal ganglion cells (RGC) stabilizes retinotopic synapses via a postsynaptic NMDAR (N -methyl- D -aspartate receptor)-dependent mechanism. Blocking NMDARs makes individual axonal arbors larger, which underlies an unsharpened map, and also increases branch turnover, as if a stabilizing factor from the postsynaptic partner is no longer released. Arachidonic acid (AA), a candidate retrograde stabilizing factor, is released by cytoplasmic phospholipase A2 (cPLA2) after Ca2+ entry through activated NMDARs, and can activate presynaptic protein kinase C to phosphorylate various substrates such as GAP43 to regulate cytoskeletal dynamics. To test the role of cPLA2 in the retinotectal system of developing zebrafish, we first used PED6, a fluorescent reporter of cPLA2 activity, to show that 1,3 min of strobe flashes activated tectal cPLA2 by an NMDAR-dependent mechanism. Second, we imaged the dynamic growth of retinal arbors during both local inhibition of tectal cPLA2 by a pharmacological inhibitor, arachidonic tri-fluoromethylketone, and its suppression by antisense oligonucleotides (both injected intraventricularly). Both methods produced larger arbors and faster branch dynamics as occurs with blocking NMDARs. In contrast, intraocular suppression of retinal cPLA2 with large doses of antisense oligos produced none of the effects of tectal cPLA2 inhibition. Finally, if AA is the retrograde messenger, the application of exogenous AA to the tectum should reverse the increased branch turnover caused by blocking either NMDARs or cPLA2. In both cases, intraventricular injection of AA stabilized the overall branch dynamics, bringing rates down below the normal values. The results suggest that AA generated postsynaptically by cPLA2 downstream of Ca2+ entry through NMDARs acts as a retrograde signal to regulate the dynamic growth of retinal arbors. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2008. [source]

    Comparative pathogenesis of Mycobacterium marinum and Mycobacterium tuberculosis

    CELLULAR MICROBIOLOGY, Issue 5 2008
    David M. Tobin
    Summary A thorough understanding of Mycobacterium tuberculosis pathogenesis in humans has been elusive in part because of imperfect surrogate laboratory hosts, each with its own idiosyncrasies. Mycobacterium marinum is the closest genetic relative of the M. tuberculosis complex and is a natural pathogen of ectotherms. In this review, we present evidence that the similar genetic programmes of M. marinum and M. tuberculosis and the corresponding host immune responses reveal a conserved skeleton of Mycobacterium host,pathogen interactions. While both species have made niche-specific refinements, an essential framework has persisted. We highlight genetic comparisons of the two organisms and studies of M. marinum in the developing zebrafish. By pairing M. marinum with the simplified immune system of zebrafish embryos, many of the defining mechanisms of mycobacterial pathogenesis can be distilled and investigated in a tractable host/pathogen pair. [source]