Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA.
Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, 92093, USA.
Sci Rep. 2020 Jun 26;10(1):10443. doi: 10.1038/s41598-020-67209-w.
Bioluminescence, or the production of light by living organisms via chemical reaction, is widespread across Metazoa. Laboratory culture of bioluminescent organisms from diverse taxonomic groups is important for determining the biosynthetic pathways of bioluminescent substrates, which may lead to new tools for biotechnology and biomedicine. Some bioluminescent groups may be cultured, including some cnidarians, ctenophores, and brittle stars, but those use luminescent substrates (luciferins) obtained from their diets, and therefore are not informative for determination of the biosynthetic pathways of the luciferins. Other groups, including terrestrial fireflies, do synthesize their own luciferin, but culturing them is difficult and the biosynthetic pathway for firefly luciferin remains unclear. An additional independent origin of endogenous bioluminescence is found within ostracods from the family Cypridinidae, which use their luminescence for defense and, in Caribbean species, for courtship displays. Here, we report the first complete life cycle of a luminous ostracod (Vargula tsujii Kornicker & Baker, 1977, the California Sea Firefly) in the laboratory. We also describe the late-stage embryogenesis of Vargula tsujii and discuss the size classes of instar development. We find embryogenesis in V. tsujii ranges from 25-38 days, and this species appears to have five instar stages, consistent with ontogeny in other cypridinid lineages. We estimate a complete life cycle at 3-4 months. We also present the first complete mitochondrial genome for Vargula tsujii. Bringing a luminous ostracod into laboratory culture sets the stage for many potential avenues of study, including learning the biosynthetic pathway of cypridinid luciferin and genomic manipulation of an autogenic bioluminescent system.
生物发光，即生物体通过化学反应产生光，在后生动物中广泛存在。从不同分类群的生物发光生物体中进行实验室培养，对于确定生物发光底物的生物合成途径非常重要，这可能会为生物技术和生物医学带来新的工具。一些发光群体可以进行培养，包括一些刺胞动物、栉水母和棘皮动物，但它们使用的是从饮食中获得的发光底物（荧光素），因此对于确定荧光素的生物合成途径没有信息价值。其他群体，包括陆生萤火虫，确实合成自己的荧光素，但培养它们很困难，萤火虫荧光素的生物合成途径仍不清楚。另外一个独立的内源性生物发光起源于介形纲家族的介形虫，它们利用发光进行防御，在加勒比物种中用于求偶展示。在这里，我们报告了第一个在实验室中完成的发光介形虫（Vargula tsujii Kornicker & Baker, 1977，加利福尼亚海萤火虫）的完整生命周期。我们还描述了 Vargula tsujii 的晚期胚胎发生，并讨论了幼虫发育的大小等级。我们发现 V. tsujii 的胚胎发生时间在 25-38 天之间，并且该物种似乎有五个幼虫阶段，与其他介形虫谱系的个体发生一致。我们估计一个完整的生命周期为 3-4 个月。我们还展示了第一个完整的 Vargula tsujii 线粒体基因组。将发光介形虫引入实验室培养为许多潜在的研究途径奠定了基础，包括学习生物发光底物的生物合成途径和对自主生物发光系统进行基因组操作。
