Marine organisms are able to produce light using either their own luminous system, called intrinsic bioluminescence, or symbiotic luminous bacteria, called extrinsic bioluminescence. Among bioluminescent vertebrates, Osteichthyes are known to harbor both types of bioluminescence, while no study has so far addressed the potential use of intrinsic/extrinsic luminescence in elasmobranchs. In sharks, two families are known to emit light: Etmopteridae and Dalatiidae. The deep-sea bioluminescent Etmopteridae, Etmopterus spinax, has received a particular interest over the past fifteen years and its bioluminescence control was investigated in depth. However, the nature of the shark luminous system still remains enigmatic. The present work was undertaken to assess whether the light of this shark species originates from a bioluminescent bacterial symbiosis. Using fluorescent in situ hybridization (FISH) and transmission electron microscopy (TEM) image analyses, this study supports the conclusion that the bioluminescence in the deep-sea lanternshark, Etmopterus spinax, is not of bacterial origin.

中文翻译：

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Etmopterus spinax（天鹅绒腹部灯笼鲨）不使用细菌发光。

海洋生物能够使用其自身的发光系统（称为内在生物发光）或共生发光细菌（称为外在生物发光）来发光。在生物发光的脊椎动物中，已知鸵鸟皮具有两种类型的生物发光，而迄今为止，还没有研究涉及在弹性分支中固有/外部发光的潜在用途。在鲨鱼中，已知有两个家族发光：t科和and科。在过去的十五年中，深海生物发光的鞘翅目Etmopterus spinax受到了特别关注，并且对其生物发光控制进行了深入研究。但是，鲨鱼发光系统的本质仍然是难以捉摸的。进行本工作以评估该鲨鱼种类的光是否源自生物发光细菌共生。