DAO 77:73-82 (2007)  -  DOI: https://doi.org/10.3354/dao01821

Microbiological study of the body wall lesions of the echinoid Tripneustes gratilla

Pierre Becker1,*, David C. Gillan2, Igor Eeckhaut1

1Laboratoire de biologie marine, Université de Mons-Hainaut, 6 avenue du Champ de Mars, 7000 Mons, Belgium
2Laboratoire de biologie marine, CP160/15, Université Libre de Bruxelles, 50 avenue F. D. Roosevelt, 1050 Bruxelles, Belgium

ABSTRACT: The microbiota of the body wall lesions of the echinoid Tripneustes gratilla, initiated by the grazing action of the parasitic gastropod Vexilla vexillum, was investigated with a pluridisciplinary approach. Parasitised sea urchins showed body wall lesions strongly infected by bacteria that progressed through the test and reached the cœlomic cavity after ca. 1 mo. We report here on the bacterial community observed in lesions of echinoids collected in situ and on the bacteria that successively appeared during laboratory experiments. Two Alphaproteobacteria, a CFB (CytophagaFlavobacteriumBacteroides) bacterium, 3 Vibrio species and Exiguobacterium aestuarii were identified in the field-collected lesions by 16S rDNA sequencing. The last 4 bacteria were cultured and each induced the disease when inoculated on scalpel-made wounds, with 100% of the individuals infected within 2 d. Scalpel-induced scarifications tended to heal within 3 wk, while gastropod-induced lesions evolved into disease, suggesting a role of Vexilla vexillum in the development of the infection. Denaturing gradient gel electrophoresis (DGGE) and sequencing suggest that (1) bacteria associated with healthy integument were not present in the lesions and were thus not responsible for their infection, (2) Alphaproteobacteria with close phylogenetic affiliation with other bacteria involved in several diseases affecting marine invertebrates were present, and (3) these Alphaproteobacteria were present from the beginning of the infection and appeared earlier in the infection than other bacteria such as CFB bacteria.


KEY WORDS: Echinoderm · DGGE · Bacteria · Infection · Lesion · Gastropod


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Cite this article as: Becker P, Gillan DC, Eeckhaut I (2007) Microbiological study of the body wall lesions of the echinoid Tripneustes gratilla. Dis Aquat Org 77:73-82. https://doi.org/10.3354/dao01821

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