Symbiosis, Morphology, and Phylogeny of Hoplonymphidae (Parabasalia) of the Wood-Feeding Roach Cryptocercus punctulatus
Symbiosis, Morphology, and Phylogeny of Hoplonymphidae (Parabasalia) of the Wood-Feeding Roach Cryptocercus punctulatus
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DOI：
10.1111/j.1550-7408.2011.00564.x
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发表时间：
2011-09-01
影响因子：
2.2
通讯作者：
Keeling, Patrick J.
中科院分区：
文献类型：
--
作者：
Carpenter, Kevin J.;Horak, Ales;Keeling, Patrick J.
低等白蚁和食木蟑螂隐尾虫后肠中的厌氧纤维素降解鞭毛虫原生生物对其宿主消化木质纤维素的能力至关重要。许多细菌与它们的表面和细胞质囊泡相关，分子和其他数据表明，这可能是重要的共生体。这些共生的一些最引人注目的例子是在parabasalid家庭Hoplonymphidae，但很少或根本没有数据存在的结构方面，他们的共生关系，通过不同的生命周期阶段与细菌，或其多样性和系统发育关系在隐尾虫。我们调查了这些地区的hoplonymphid属Barbulanympha和Urinympha从Cryptocercus punctulatus使用光学显微镜和电子显微镜，小亚基rRNA的分析。显微镜检查揭示了与生命周期阶段相关的细菌表面共生体密度的变化，在细菌粘附和/或代谢物交换中可能重要的糖萼，以及与细菌表面共生体相关的推定病毒。表面细菌的图案表明，从抗性（休眠）阶段出现的原生生物被一小群细菌细胞定殖，然后分裂以覆盖其表面。此外，原生生物的细胞质突起被细菌覆盖。系统发育分析拒绝单系的Hoplonymphidae，这表明多个起源或这些细菌共生的损失。
Anaerobic cellulolytic flagellate protists of the hindguts of lower termites and the wood-feeding cockroach Cryptocercus are essential to their host's ability to digest lignocellulose. Many have bacteria associated with their surfaces and within cytoplasmic vesicles-likely important symbioses as suggested by molecular and other data. Some of the most striking examples of these symbioses are in the parabasalid family Hoplonymphidae, but little or no data exist on the structural aspects of their symbioses, their relationships with bacteria through different life-cycle stages, or their diversity and phylogenetic relationships in Cryptocercus. We investigated these areas in the hoplonymphid genera Barbulanympha and Urinympha from Cryptocercus punctulatus using light and electron microscopy, and analysis of small subunit rRNA. Microscopy reveals variation in density of bacterial surface symbionts related to life-cycle stage, a glyococalyx possibly important in bacterial adhesion and/or metabolite exchange, and putative viruses associated with bacterial surface symbionts. Patterning of surface bacteria suggests protists emerging from the resistant (dormant) stage are colonized by a small population of bacterial cells, which then divide to cover their surface. Additionally, cytoplasmic protrusions from the protist are covered by bacteria. Phylogenetic analysis rejects the monophyly of Hoplonymphidae, suggesting multiple origins or losses of these bacterial symbioses.