Quorum Signaling and Symbiosis in the Marine Luminous Bacterium Vibrio fischeri

ABSTRACTChitin, a polymer ofN-acetylglucosamine (GlcNAc), is noted as the second most abundant biopolymer in nature. Chitin serves many functions for marine bacteria in the familyVibrionaceae(“vibrios”), in some instances providing a physical attachment site, inducing natural genetic competence, and serving as an attractant for chemotaxis. The marine luminous bacteriumVibrio fischeriis 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. fischericells are harvested from seawater during each host generation, andV. fischeriis 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. fischeriuses 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.

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Two active forms of the accessory yellow fluorescence protein of the luminous bacterium Vibrio fischeri strain Y1

Journal of Photochemistry and Photobiology B Biology ◽

10.1016/1011-1344(93)80068-k ◽

1993 ◽

Vol 18 (2-3) ◽

pp. 227-232 ◽

Cited By ~ 20

Author(s):

Hajime Karatani ◽

J.Woodland Hastings

Keyword(s):

Vibrio Fischeri ◽

Luminous Bacterium ◽

Yellow Fluorescence ◽

Yellow Fluorescence Protein ◽

Fluorescence Protein

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Purification and Properties of a Proteinase from a Marine Luminous Bacterium,Vibrio harveyiStrain FLA-11

Agricultural and Biological Chemistry ◽

10.1080/00021369.1988.10868692 ◽

1988 ◽

Vol 52 (2) ◽

pp. 435-441

Author(s):

Shigeki Fukasawa ◽

Kenji Nakamura ◽

Atsushi Kamii ◽

Yoshitaka Ohyama ◽

Masako Osumi

Keyword(s):

Luminous Bacterium ◽

Marine Luminous Bacterium ◽

Purification And Properties

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Population Dynamics of Vibrio fischeri during Infection of Euprymna scolopes

Applied and Environmental Microbiology ◽

10.1128/aem.69.10.5928-5934.2003 ◽

2003 ◽

Vol 69 (10) ◽

pp. 5928-5934 ◽

Cited By ~ 85

Author(s):

Jessica McCann ◽

Eric V. Stabb ◽

Deborah S. Millikan ◽

Edward G. Ruby

Keyword(s):

Population Dynamics ◽

Vibrio Fischeri ◽

Single Copy ◽

Bacterial Cells ◽

Euprymna Scolopes ◽

Wild Type ◽

Luminous Bacterium ◽

Ambient Seawater ◽

Light Emitting ◽

Low Concentrations

ABSTRACT 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.

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