The inner-core lipopolysaccharide biosynthetic waaE gene: function and genetic distribution among some Enterobacteriaceae b bThe GenBank accession number for the waaE gene sequences of P. mirabilis CECT170, Y. enterocolitica R102 and Ent. aerogenes CECT684 reported in this paper are AY075039, AY075041 and AY075040, respectively.

Izquierdo, Luís; Abitiu, Nihal; Coderch, Núria; Hita, Beatriz; Merino, Susana; Gavı́n, Rosalina; Tomás, Juan M.; Regué, Miguel

doi:10.1099/00221287-148-11-3485

Cited by 36 publications

(29 citation statements)

References 45 publications

(54 reference statements)

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“…S4 in the supplemental material at http://www.uni-wuerzburg.de/infektionsbiologie/imistart.htm and at http://www.pasteur.fr/recherche/unites/Ggb/supmat.html). In previous reports workers described LPS as a molecule that is important for adhesion of different pathogenic bacteria, such as Pseudomonas fluorescens, Serratia marcescens, and Klebsiella pneumoniae (23,45), to abiotic surfaces. The absence of biofilm formation by strain 536waaG is consistent with these reports and suggests that LPS, especially the LPS core, is critical for adhesion of E. coli strain 536 to abiotic surfaces (Fig.…”

Section: Discussionmentioning

confidence: 99%

The Transcriptional Antiterminator RfaH Represses Biofilm Formation inEscherichia coli

et al. 2006

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We investigated the influence of regulatory and pathogenicity island-associated factors (Hha, RpoS, LuxS, EvgA, RfaH, and tRNA 5 Leu ) on biofilm formation by uropathogenic Escherichia coli (UPEC) strain 536. Only inactivation of rfaH, which encodes a transcriptional antiterminator, resulted in increased initial adhesion and biofilm formation by E. coli 536. rfaH inactivation in nonpathogenic E. coli K-12 isolate MG1655 resulted in the same phenotype. Transcriptome analysis of wild-type strain 536 and an rfaH mutant of this strain revealed that deletion of rfaH correlated with increased expression of flu orthologs. flu encodes antigen 43 (Ag43), which mediates autoaggregation and biofilm formation. We confirmed that deletion of rfaH leads to increased levels of flu and flu-like transcripts in E. coli K-12 and UPEC. Supporting the hypothesis that RfaH represses biofilm formation through reduction of the Ag43 level, the increased-biofilm phenotype of E. coli MG1655rfaH was reversed upon inactivation of flu. Deletion of the two flu orthologs, however, did not modify the behavior of mutant 536rfaH. Our results demonstrate that the strong initial adhesion and biofilm formation capacities of strain MG1655rfaH are mediated by both increased steady-state production of Ag43 and likely increased Ag43 presentation due to null rfaH-dependent lipopolysaccharide depletion. Although the roles of rfaH in the biofilm phenotype are different in UPEC strain 536 and K-12 strain MG1655, this study shows that RfaH, in addition to affecting the expression of bacterial virulence factors, also negatively controls expression and surface presentation of Ag43 and possibly another Ag43-independent factor(s) that mediates cell-cell interactions and biofilm formation.

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Section: Discussionmentioning

confidence: 99%

The Transcriptional Antiterminator RfaH Represses Biofilm Formation inEscherichia coli

et al. 2006

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“…1. Conserved region in the core LPS structure of K. pneumoniae (29) and genes involved in inner core biosynthesis (24,14). Kdop, 3-deoxy-D-manno-octulopyranosonic acid; Glcp, D-glucopyranose; GlcNp, glucosamine; GalAp, galacturonic acid.…”

Section: Methodsmentioning

confidence: 99%

“…We have previously reported the nucleotide sequence of the K. pneumoniae waa gene cluster and have identified the functions of the genes involved in the biosynthesis of its inner core LPS (Kdo, L,DHeppI, L,D-HeppII, L,D-HeppIII, and branched D-Glcp transferases) (14,24). Comparison of the known outer core LPS structures among Enterobacteriaceae revealed that the first outer core residue is either D-Glc or D-GalA, linked to the L,D-HeppII residue by an ␣1,3 bond.…”

Section: Construction Of K Pneumoniae Wabg Mutantsmentioning

confidence: 99%

“…In view of the peculiarities of the K. pneumoniae core LPS, we sought in this work to determine the importance of the outer core LPS in K. pneumoniae outer membrane permeability and in pathogenesis. The previous knowledge of the K. pneumoniae waa gene cluster (the nomenclature proposed by Reeves et al [23] for proteins and genes involved in core LPS biosynthesis is used in this work) and the elucidation of the genes involved in its inner core biosynthesis (14,24) (Fig. 1) facilitated the identification of the gene involved in the transfer of the first outer core residue to construct and characterize K. pneumoniae mutants devoid of the outer core LPS.…”

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The Klebsiella pneumoniae wabG Gene: Role inBiosynthesis of the Core Lipopolysaccharide andVirulence

Izquierdo

Coderch²,

Piqué³

et al. 2003

J Bacteriol

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To determine the function of the wabG gene in the biosynthesis of the core lipopolysaccharide (LPS) of Klebsiella pneumoniae, we constructed wabG nonpolar mutants. Data obtained from the comparative chemical and structural analysis of LPS samples obtained from the wild type, the mutant strain, and the complemented mutant demonstrated that the wabG gene is involved in attachment to ␣-L-glycero-D-manno-heptopyranose II (L,D-HeppII) at the O-3 position of an ␣-D-galactopyranosyluronic acid (␣-D-GalAp) residue. K. pneumoniae nonpolar wabG mutants were devoid of the cell-attached capsular polysaccharide but were still able to produce capsular polysaccharide. Similar results were obtained with K. pneumoniae nonpolar waaC and waaF mutants, which produce shorter LPS core molecules than do wabG mutants. Other outer core K. pneumoniae nonpolar mutants in the waa gene cluster were encapsulated. K. pneumoniae waaC, waaF, and wabG mutants were avirulent when tested in different animal models. Furthermore, these mutants were more sensitive to some hydrophobic compounds than the wild-type strains. All these characteristics were rescued by reintroduction of the waaC, waaF, and wabG genes from K. pneumoniae.In gram-negative bacteria the lipopolysaccharide (LPS) is one of the major structural and immunodominant molecules of the outer membrane. LPS consists of three domains: lipid A, core oligosaccharide, and O-specific antigen or O side chain. In smooth LPS, the core region is conceptually divided into two regions: a lipid A proximal inner core and an outer core that provides the attachment site for the O antigen (21). Comparison of the known core LPS structures from Enterobacteriaceae organisms reveals that the first outer core residue might be either glucose (Glc) or a galacturonic acid (GalA) residue. In the four known Escherichia coli core types and in Salmonella enterica, a substitution of the L-glycero-D-manno-heptopyranose II (L,D-HeppII) at the O-3 position for a Glcp residue was found (12). For Klebsiella pneumoniae, Proteus mirabilis, and Yersinia enterocolitica, a substitution of the L,D-HeppII at the O-3 position for an ␣-D-galacturonic acid residue (␣-DGalpA) residue has been described (20,29,30). On the other hand, in most of the Enterobacteriaceae studied, the core LPS contains inner core phosphoryl modifications (21), but K. pneumoniae core LPS is devoid of such modifications (29) (Fig. 1).Important roles in outer membrane permeability and in pathogenesis have been shown for the outer core and for the negative charges contributed by phosphoryl inner core modification in E. coli and/or S. enterica serovar Typhimurium (32,33,34). In view of the peculiarities of the K. pneumoniae core LPS, we sought in this work to determine the importance of the outer core LPS in K. pneumoniae outer membrane permeability and in pathogenesis. The previous knowledge of the K. pneumoniae waa gene cluster (the nomenclature proposed by Reeves et al. [23] for proteins and genes involved in core LPS biosynthesis is used in this work) and t...

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“…1). Furthermore the functions in both inner and outer core biosynthesis of most of the transferases encoded by the wa gene products have been elucidated (7)(8)(9)(10)(11)(12) (Fig. 1).…”

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The Incorporation of Glucosamine into Enterobacterial Core Lipopolysaccharide

Regué

Izquierdo

Fresno

et al. 2005

Journal of Biological Chemistry

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The core lipopolysaccharide (LPS) of Klebsiella pneumoniae is characterized by the presence of disaccharide ␣GlcN-(1,4)-␣GalA attached by an ␣1,3 linkage to L-glycero-D-manno-heptopyranose II (LD-HeppII). Previously it has been shown that the WabH enzyme catalyzes the incorporation of GlcNAc from UDP-GlcNAc to outer core LPS. The presence of GlcNAc instead of GlcN and the lack of UDP-GlcN in bacteria indicate that an additional enzymatic step is required. In this work we identified a new gene (wabN) in the K. pneumoniae core LPS biosynthetic cluster. Chemical and structural analysis of K. pneumoniae non-polar wabN mutants showed truncated core LPS with GlcNAc instead of GlcN. In vitro assays using LPS truncated at the level of D-galacturonic acid (GalA) and cell-free extract containing WabH and WabN together led to the incorporation of GlcN, whereas none of them alone were able to do it. This result suggests that the later enzyme (WabN) catalyzes the deacetylation of the core LPS containing the GlcNAc residue. Thus, the incorporation of the GlcN residue to core LPS in K. pneumoniae requires two distinct enzymatic steps. WabN homologues are found in Serratia marcescens and some Proteus strains that show the same disaccharide ␣GlcN-(1,4)-␣GalA attached by an ␣1,3 linkage to LD-HeppII.

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Cited by 36 publications

References 45 publications

The Transcriptional Antiterminator RfaH Represses Biofilm Formation inEscherichia coli

The Transcriptional Antiterminator RfaH Represses Biofilm Formation inEscherichia coli

The Klebsiella pneumoniae wabG Gene: Role inBiosynthesis of the Core Lipopolysaccharide andVirulence

The Incorporation of Glucosamine into Enterobacterial Core Lipopolysaccharide

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