Population dynamics of Vibrio fischeri during infection of Euprymna scolopes
Population dynamics of Vibrio fischeri during infection of Euprymna scolopes
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DOI：
10.1128/aem.69.10.5928-5934.2003
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发表时间：
2003-10-01
影响因子：
4.4
通讯作者：
Ruby, EG
中科院分区：
文献类型：
--
作者：
McCann, J;Stabb, EV;Ruby, EG
发光细菌费氏弧菌（Vibrio fischeri）在它的宿主乌贼（Euprymna scoles）体内寄居了一个专门的发光器官。刚孵出的幼乌贼必须从周围的海水中获取共生体，那里的细菌浓度很低。为了更全面地了解费氏弧菌在定植过程中的种群动态，我们使用mini-Tn7转座子标记抗生素耐药性细菌，以便监测其后代的生长情况。当培养时，携带转座子的费氏弧菌细胞没有检测到代谢负担，该转座子插入费氏弧菌基因组的特定基因间区域的单个拷贝。在共接种实验中，标记为mini-Tn7的菌株在感染宿主和在宿主内繁殖的能力方面似乎与野生型相当。对定植早期阶段的研究表明，当动物接触相当于自然种群水平的费氏弧菌细胞接种3小时后，只有少数细菌与共生组织相关；然而，所有这些宿主都被感染了。当三种不同标记的费氏弧菌与幼乌贼共孵育时，从单个共生器官中恢复的菌株数量直接依赖于接种量的大小。此外，这些结果表明，当暴露于少量的费氏弧菌时，宿主可能只被一个或几个细菌细胞定植，这表明共生感染是高效的。
The luminous bacterium Vibrio fischeri colonizes a specialized light-emitting organ within its squid host, Euprymna scolopes. Newly hatched juvenile squid must acquire their symbiont from ambient seawater, where the bacteria are present at low concentrations. To understand the population dynamics of V. fischeri during colonization more fully, we used mini-Tn7 transposons to mark bacteria with antibiotic resistance so that the growth of their progeny could be monitored. When grown in culture, there was no detectable metabolic burden on V. fischeri cells carrying the transposon, which inserts in single copy in a specific intergenic region of the V. fischeri genome. Strains marked with mini-Tn7 also appeared to be equivalent to the wild type in their ability to infect and multiply within the host during coinoculation experiments. Studies of the early stages of colonization suggested that only a few bacteria became associated with symbiotic tissue when animals were exposed for a discrete period (3 h) to an inoculum of V. fischeri cells equivalent to natural population levels; nevertheless, all these hosts became infected. When three differentially marked strains of V. fischeri were coincubated with juvenile squid, the number of strains recovered from an individual symbiotic organ was directly dependent on the size of the inoculum. Further, these results indicated that, when exposed to low numbers of V. fischeri, the host may become colonized by only one or a few bacterial cells, suggesting that symbiotic infection is highly efficient.