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  • 1
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Photophores in Porichthys notatus are bioluminescent organs composed of a lens, photogenic tissue, and an underlying reflector. Nerves penetrate through the reflector and branch, free of their Schwann cells, among the photogenic tissue elements. The tortuous pathways of axons have been followed by electron microscopical serial sections. After giving off occasional terminal branches, the axons continue into pockets of connective tissue which penetrate among the photogenic, supportive, and lens cells. There they form tuft-like clusters of nerve endings, some of which contain dense-cored vesicles. None of these endings was seen to penetrate the basal lamina and make direct intercellular contact with either a supportive cell or a photogenic cell. From these observations, it is concluded that the nerves end outside of the basal lamina surrounding photogenic, supportive, and lens cells. Adhesion sites, which may indicate chemical synaptic contact, were occasionally observed among these neural components.The photophores of the California Porichthys notatus often bioluminesce following intraperitoneal injection of the fish with epinephrine. It therefore appears from experimental, anatomical and fine structural evidence, that these luminescent organs are innervated and controlled by the sympathetic nervous system.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Photophores in Porichthys notatus consist of a cellular lens, an underlying area of photogenic tissue and a deep ensheathing reflector. Lens cells exhibit a dense compacted filamentous cytoplasm. Their processes interdigitate and desmosomes exist along their borders. The photogenic tissue, richly supplied by blood vessels, consists of two main cell types: (1) a presumed “photogenic” cell; and (2) a supportive cell. Photogenic cells are characterized by a highly vesiculated cytoplasm and peripheral microvilli. Frequently, they exhibit lamellar membranous whorls. Some whorls display cytoplasmic cores with vesicles. Many of these vesicles communicate via pores with an extracellular channel that envelops the cells. Supportive cells contain cytoplasmic filaments and extend processes around the photogenic cells. Except for isolated desmosomal contact points, a wide extracellular channel intervenes between supportive and photogenic cells. A prominent basal lamina separates supportive cells from the surrounding connective tissue. The strongly birefringent reflector is composed primarily of cells containing guanine crystals. The crystals lie stacked in groups, each membrane-bounded crystal being separated from its neighbor by an intervening layer of cytoplasm. Such an arrangement produces constructive interference and accounts for the high reflectivity of this multilayered structure. Possible relationships of the above structural features and the production of light are discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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