title: Environmental and biofilm-dependent changes in a Bacillus cereus secondary cell wall polysaccharide.
abstract: Bacterial species from the Bacillus genus, including Bacillus cereus and Bacillus anthracis, synthesize secondary cell wall polymers (SCWP) covalently associated to the peptidoglycan through a phospho-diester linkage. Although such components were observed in a wide panel of B. cereus and B. anthracis strains, the effect of culture conditions or of bacterial growth state on their synthesis has never been addressed. Herein we show that B. cereus ATCC 14579 can synthesize not only one, as previously reported, but two structurally unrelated secondary cell wall polymers (SCWP) polysaccharides. The first of these SCWP, →4)[GlcNAc(β1-3)]GlcNAc(β1-6)[Glc(β1-3)][ManNAc(α1-4)]GalNAc(α1-4)ManNAc(β1→, although presenting an original sequence, fits to the already described the canonical sequence motif of SCWP. In contrast, the second polysaccharide was made up by a totally original sequence, →6)Gal(α1-2)(2-R-hydroxyglutar-5-ylamido)Fuc2NAc4N(α1-6)GlcNAc(β1→, which no equivalent has ever been identified in the Bacillus genus. In addition, we established that the syntheses of these two polysaccharides were differently regulated. The first one is constantly expressed at the surface of the bacteria, whereas the expression of the second is tightly regulated by culture conditions and growth states, planktonic, or biofilm.
authors.affiliation: Université de Lille1, Unité de Glycobiologie Structurale et Fonctionnelle, F-59650 Villeneuve d'Ascq, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Candela
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Maes
authors.forename: Estelle
authors.initials: E
authors.lastname: Garénaux
authors.forename: Yoann
authors.initials: Y
authors.lastname: Rombouts
authors.forename: Frédéric
authors.initials: F
authors.lastname: Krzewinski
authors.forename: Michel
authors.initials: M
authors.lastname: Gohar
authors.forename: Yann
authors.initials: Y
authors.lastname: Guérardel
mesh_terms: D001409:Bacillus cereus / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002473:Cell Wall / Q000737:chemistry*; D015964:Gene Expression Regulation, Bacterial; D011134:Polysaccharides / Q000096:biosynthesis / Q000737:chemistry*
chemical_list: D011134:Polysaccharides