Lipopolysaccharides from Commensal and Opportunistic Bacteria: Characterization and Response of the Immune System of the Host Sponge Suberites domuncula.
Marine sponges harbor a rich bacterioflora with which they maintain close relationships. However, the way these animals make the distinction between bacteria which are consumed to meet their metabolic needs and opportunistic and commensal bacteria which are hosted is not elucidated. Among the elements participating in this discrimination, bacterial cell wall components such as lipopolysaccharides (LPS) could play a role. In the present study, we investigated the LPS chemical structure of two bacteria associated with the sponge Suberites domuncula: a commensal Endozoicomonas sp. and an opportunistic Pseudoalteromonas sp. Electrophoretic patterns indicated different LPS structures for these bacteria. The immunomodulatory lipid A was isolated after mild acetic acid hydrolysis. The electrospray ionization ion-trap mass spectra revealed monophosphorylated molecules corresponding to tetra- and pentaacylated structures with common structural features between the two strains. Despite peculiar structural characteristics, none of these two LPS influenced the expression of the macrophage-expressed gene S. domuncula unlike the Escherichia coli ones. Further research will have to include a larger number of genes to understand how this animal can distinguish between LPS with resembling structures and discriminate between bacteria associated with it.
University of South Brittany, EA 3884, LBCM, IUEM, F-56100 Lorient, France. jgarderes@mnhn.fr.
Johan
J
Gardères
University of South Brittany, EA 3884, LBCM, IUEM, F-56100 Lorient, France. gilles.bedoux@univ-ubs.fr.
Gilles
G
Bedoux
University of South Brittany, EA 3884, LBCM, IUEM, F-56100 Lorient, France. vassiakouts88@gmail.com.
Vasiliki
V
Koutsouveli
University of South Brittany, EA 3884, LBCM, IUEM, F-56100 Lorient, France. sterenn.crequer@univ-ubs.fr.
Sterenn
S
Crequer
University of South Brittany, EA 3884, LBCM, IUEM, F-56100 Lorient, France. floriedesriac@hotmail.fr.
Florie
F
Desriac
University of South Brittany, EA 3884, LBCM, IUEM, F-56100 Lorient, France. gael.le-pennec@univ-ubs.fr.
Gaël Le
GL
Pennec
D019342:Acetic Acid / Q000276:immunology; D000818:Animals; D001419:Bacteria / Q000276:immunology*; D002473:Cell Wall / Q000276:immunology; D015870:Gene Expression / Q000276:immunology; D006868:Hydrolysis; D008050:Lipid A / Q000276:immunology; D008070:Lipopolysaccharides / Q000276:immunology*; D008264:Macrophages / Q000276:immunology; D010802:Phylogeny; D011161:Porifera / Q000276:immunology* / Q000382:microbiology*; D047233:Suberites / Q000276:immunology* / Q000382:microbiology*
D008050:Lipid A; D008070:Lipopolysaccharides; D019342:Acetic Acid
Porifera; immunity; lipopolysaccharide; macrophage-expressed gene; sponge-associated bacteria; symbiosis