Bacterial symbionts colonize the accessory nidamental gland of the squid Loligo opalescens via horizontal transmission
Bacterial symbionts colonize the accessory nidamental gland of the squid Loligo opalescens via horizontal transmission
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DOI：
10.2307/1542511
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发表时间：
1998-02-01
影响因子：
1.6
通讯作者：
Epel, D
中科院分区：
文献类型：
--
作者：
Kaufman, MR;Ikeda, Y;Epel, D
附件nidamental腺（AN腺），成熟的雌性鱿鱼Loligo opalescens的生殖器官，窝藏一个密集的文化的细菌的功能不明。一个多层鞘周围的L，opalescens卵壳类似的殖民地的细菌，推测起源于AN，oland，证明了它们的存在，在产卵的卵壳。本研究调查这些细菌是如何传播到少年鱿鱼和检查一些形态学的后果细菌定植的AN腺组织。通过对成鱼AN腺结构和人工饲养幼鱼AN腺的发育及细菌定植的观察，我们确定在刚孵化的鱿鱼中AN腺是不存在的，直到孵化后87天才出现。在孵化后129天，器官显示由单层上皮细胞组成的小管，并表达大量纤毛和微绒毛。这些小管尚未完全形成，因此对外套腔和外部海水开放，可能有助于微生物的获取。由于孵化后AN腺发展了相当长的时间，它最有可能获得其共生体水平从环境海水，而不是垂直从卵壳鞘。从纤毛的表达到上皮细胞表面微绒毛的产生的开关可能决定了细菌定植的组织的能力，幼年和成年AN腺体的电子显微镜检查显示，类似的过程发生在其他头足类动物物种的相关光器官的发展过程中，窝藏共生细菌。
The accessory nidamental gland (AN gland), a reproductive organ of the mature female squid Loligo opalescens, harbors a dense culture of bacteria of unknown function. A multilayered sheath surrounding the L, opalescens egg case is similarly colonized by bacteria that presumably originate in the AN,oland, as evidenced by their presence in the egg case at oviposition. This study investigates how these bacteria are transmitted to juvenile squid and examines some morphological consequences of bacterial colonization of AN gland tissues. By observing the structure of the AN gland in adults and the development and bacterial colonization of the gland in juveniles raised in captivity, we determined that the AN gland was absent in newly hatched squid and did not appear until 87 days post-hatching. At 129 days posthatching, the organ displayed tubules composed of a single layer of epithelial cells and expressing numerous cilia and microvilli. These tubules were not yet fully formed and thus were open to the mantle cavity and external seawater, possibly to aid in the acquisition of microorganisms. Since the AN gland developed a considerable time after hatching, it most likely acquires its symbionts horizontally from environmental seawater and not vertically from the egg case sheath. The switch from expression of cilia to production of microvilli on the epithelial cell surface may dictate the competence of the tissue for bacterial colonization, Electron microscopic examination of juvenile and adult AN glands revealed that an analogous process occurs during the development of the related light organ of other cephalopod species that harbor symbiotic bacteria.