Biomaterial Database

The developmental morphology of Torpedo marmorata: electric organ--electrogenic phase. 1979

G Q Fox, and G P Richardson

The electrogenic developmental phase of the electric organ of Torpedo marmorata begins at 40 mm of embryo length and is characterized by a horizontal flattening of the vertically orientated myotubes. The first sign of this process is a rounding up of the ventral poles of the myotubes and a disassembly of the myofibrils located therein. Occurring concomitantly with this is a migration of the nuclei to the cell center which results in a horizontal plane of nuclei. Filament bundles are then found within the ventral cytoplasm often projecting upwards from the ventral plasma membrane. The filaments of the bundles are dimensionally similar to the myofilaments of muscle and it is suggested that the bundles play a role in cellular transformation. In contrast the dorsal pole of the cell appears to be integrated "passively" with the final cell shape as no morphological correlates of a retraction process have been found. A canalicular system, composed of a complex network of irregular tubules and vacuoles, appears just below the dorsal plasma membrane characterizing this region of the cell. A mononucleated satellite cell population lies in close proximity to the dorsal surface of the differentiating cell and fusion between the two cell types occurs throughout development. Cell shape transformation is complete by 55 mm of embryo length and the intercolumnar nerves begin to invade the interelectrocyte space. The ingrowing neurites preferentially course along the ventral electrocyte surface establishing junctions similar to motor endplates.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D002454	Cell Differentiation	Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.	Differentiation, Cell,Cell Differentiations,Differentiations, Cell
D002459	Cell Fusion	Fusion of somatic cells in vitro or in vivo, which results in somatic cell hybridization.	Cell Fusions,Fusion, Cell,Fusions, Cell
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D003599	Cytoskeleton	The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.	Cytoplasmic Filaments,Cytoskeletal Filaments,Microtrabecular Lattice,Cytoplasmic Filament,Cytoskeletal Filament,Cytoskeletons,Filament, Cytoplasmic,Filament, Cytoskeletal,Filaments, Cytoplasmic,Filaments, Cytoskeletal,Lattice, Microtrabecular,Lattices, Microtrabecular,Microtrabecular Lattices
D004557	Electric Organ	In about 250 species of electric fishes, modified muscle fibers forming disklike multinucleate plates arranged in stacks like batteries in series and embedded in a gelatinous matrix. A large torpedo ray may have half a million plates. Muscles in different parts of the body may be modified, i.e., the trunk and tail in the electric eel, the hyobranchial apparatus in the electric ray, and extrinsic eye muscles in the stargazers. Powerful electric organs emit pulses in brief bursts several times a second. They serve to stun prey and ward off predators. A large torpedo ray can produce of shock of more than 200 volts, capable of stunning a human. (Storer et al., General Zoology, 6th ed, p672)	Electric Organs,Organ, Electric,Organs, Electric
D005399	Fishes	A group of cold-blooded, aquatic vertebrates having gills, fins, a cartilaginous or bony endoskeleton, and elongated bodies covered with scales.
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013569	Synapses	Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.	Synapse