Squid-Derived Chitin Oligosaccharides Are a Chemotactic Signal during Colonization by Vibrio fischeri
Squid-Derived Chitin Oligosaccharides Are a Chemotactic Signal during Colonization by Vibrio fischeri
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DOI：
10.1128/aem.00377-12
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发表时间：
2012-07-01
影响因子：
4.4
通讯作者：
Ruby, Edward G.
中科院分区：
文献类型：
--
作者：
Mandel, Mark J.;Schaefer, Amy L.;Ruby, Edward G.
甲壳素是N-乙酰氨基葡萄糖(GlcNAc)的聚合物，被认为是自然界第二丰富的生物聚合物。甲壳素对弧菌科(“弧菌”)中的海洋细菌具有许多功能，在某些情况下提供物理附着位置，诱导自然遗传能力，并作为趋化性的引诱剂。海洋发光细菌费氏弧菌是夏威夷短尾乌贼发光器官中特有的共生体。这种细菌为鱿鱼提供发光，动物利用这种发光来进行反捕食防御，而鱿鱼则支持共生体的营养需求。每一代寄主都从海水中收获细胞，在自然界中能完成这一过程的物种只有一种。此外，甲壳素位于鱿鱼血细胞中，在共生中起着营养作用。我们在这里展示了由鱿鱼宿主产生的甲壳素低聚糖作为定植细菌的趋化信号。乌贼利用寄主甲壳素的梯度进入乌贼的光器官导管，并在动物体内定植。我们提供的证据表明，甲壳素作为一种动物产生的细菌吸引同素，在动物-细菌互惠关系中具有新的功能。
Chitin, a polymer of N-acetylglucosamine (GlcNAc), is noted as the second most abundant biopolymer in nature. Chitin serves many functions for marine bacteria in the family Vibrionaceae ("vibrios"), in some instances providing a physical attachment site, inducing natural genetic competence, and serving as an attractant for chemotaxis. The marine luminous bacterium Vibrio fischeri is the specific symbiont in the light-emitting organ of the Hawaiian bobtail squid, Euprymna scolopes. The bacterium provides the squid with luminescence that the animal uses in an antipredatory defense, while the squid supports the symbiont's nutritional requirements. V. fischeri cells are harvested from seawater during each host generation, and V. fischeri is the only species that can complete this process in nature. Furthermore, chitin is located in squid hemocytes and plays a nutritional role in the symbiosis. We demonstrate here that chitin oligosaccharides produced by the squid host serve as a chemotactic signal for colonizing bacteria. V. fischeri uses the gradient of host chitin to enter the squid light organ duct and colonize the animal. We provide evidence that chitin serves a novel function in an animal-bacterial mutualism, as an animal-produced bacterium-attracting synomone.