Spatial and temporal population dynamics of a naturally occurring two-species microbial community inside the digestive tract of the medicinal leech
Spatial and temporal population dynamics of a naturally occurring two-species microbial community inside the digestive tract of the medicinal leech
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DOI：
10.1128/aem.01833-06
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发表时间：
2007-03-01
影响因子：
4.4
通讯作者：
Graf, Joerg
中科院分区：
文献类型：
--
作者：
Kikuchi, Yoshitomo;Graf, Joerg
药用水蛭，水蛭，是最简单的自然发生的消化道共生模型之一，其中只有两个细菌物种，气单胞菌veronii bv. sobria（γ-变形菌门）和一种Rikenella样细菌（拟杆菌门），在水蛭消化道的最大隔间作物中定居。在这项研究中，我们调查的本地共生体在作物的定位和微菌落结构的空间和时间的变化，摄入无菌血粉后，通过荧光原位杂交。两种共生细菌的种群动态不同。A.除非发现与Rikenella小菌落相关，否则在喂养后14天（DAF）期间，Veronii主要作为管腔内液体（ILF）内的单个细胞被检测到。Rikenella样细菌不仅在ILF内观察到，而且还与作物上皮的腔表面相关联。Rikenella小菌落的大小在14天内动态变化。从3 daf开始，经常观察到含有两种物种的混合小菌落，两种物种的细胞彼此紧密结合。混合的小菌落的大小始终大于任何单一物种的小菌落的大小，这表明共生体的协同相互作用。用琥珀酰化麦胚凝集素进行凝集素染色，结果显示ILF中存在的嗜酸性小菌落嵌入含有N-乙酰葡糖胺的多糖基质中。这种自然发生的消化道共生的简单性、共生体-共生体相互作用和混合小菌落为理解大多数动物中更复杂的群落奠定了基础。
The medicinal leech, Hirudo verbana, is one of the simplest naturally occurring models for digestive-tract symbioses, where only two bacterial species, Aeromonas veronii bv. sobria (gamma-Proteobacteria) and a Rikenella-like bacterium (Bacteroidetes), colonize the crop, the largest compartment of the leech digestive tract. In this study, we investigated spatial and temporal changes of the localization and microcolony structure of the native symbionts in the crop, after ingestion of a sterile blood meal, by fluorescence in situ hybridization. The population dynamics differed between the two symbiotic bacteria. A. veronii was detected mainly as individual cells inside the intraluminal fluid (ILF) during 14 days after feeding (daf) unless it was found in association with Rikenella microcolonies. The Rikenella-like bacteria were observed not only inside the ILF but also in association with the luminal surface of the crop epithelium. The sizes of Rikenella microcolonies changed dynamically through the 14-day period. From 3 daf onward, mixed microcolonies containing both species were frequently observed, with cells of both species tightly associating with each other. The sizes of the mixed microcolonies were consistently larger than the size of either single-species microcolony, suggesting a synergistic interaction of the symbionts. Lectin staining with succinylated wheat germ agglutinin revealed that the planktonic microcolonies present in the ILF were embedded in a polysaccharide matrix containing N-acetylglucosamine. The simplicity, symbiont-symbiont interaction, and mixed microcolonies of this naturally occurring, digestive-tract symbiosis lay the foundation for understanding the more complex communities residing in most animals.