Studies on the Mechanism of Bacterial Resistance to Complement-Mediated Killing and on the Mechanism of Action of Bactericidal Antibody

Joiner, K A

doi:10.1007/978-3-642-45604-6_6

Cited by 52 publications

(38 citation statements)

References 95 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…All of the Rol-dependent O antigens described to date are heteropolysaccharides whose polymerization occurs via an Rfc-dependent process. Since many of these O antigens are known virulence determinants and O-chain length is known to influence serum resistance in E. coli (22,23,53), Rol may have a direct impact on virulence.…”

Section: Discussionmentioning

confidence: 99%

Distribution of the rol gene encoding the regulator of lipopolysaccharide O-chain length in Escherichia coli and its influence on the expression of group I capsular K antigens

1996

View full text Add to dashboard Cite

The rol (cld) gene encodes a protein involved in the expression of lipopolysaccharides in some members of the family Enterobacteriaceae. Rol interacts with one or more components of Rfc-dependent O-antigen biosynthetic complexes to regulate the chain length of lipopolysaccharide O antigens. The Rfc-Rol-dependent pathway for O-antigen synthesis is found in strains with heteropolysaccharide O antigens, and, consistent with this association, rol-homologous sequences were detected in chromosomal DNAs from 17 different serotypes with heteropolysaccharide O antigens. Homopolymer O antigens are synthesized by a pathway that does not involve either Rfc or Rol. It was therefore unexpected when a survey of Escherichia coli strains possessing mannose homopolymer O8 and O9 antigens showed that some strains contained rol. All 11 rol-positive strains coexpressed a group IB capsular K antigen with the O8 or O9 antigen. In contrast, 12 rol-negative strains all produced group IA K antigens in addition to the homopolymer O antigen. Previous research from this and other laboratories has shown that portions of the group I K antigens are attached to lipopolysaccharide lipid A-core, in a form that we have designated K LPS . By constructing a hybrid strain with a deep rough rfa defect, it was shown that the K40 (group IB) K LPS antigen exists primarily as long chains. However, a significant amount of K40 antigen was surface expressed in a lipid A-core-independent pathway. The typical chain length distribution of the K40 antigen was altered by introduction of multicopy rol, suggesting that the K40 group IB K antigen is equivalent to a Rol-dependent O antigen. The prototype K30 (group IA) K antigen is expressed as short oligosaccharides (primarily single repeat units) in K LPS , as well as a high-molecular-weight lipid A-core-independent form. Introduction of multicopy rol into the K30 strain generated a novel modal pattern of K LPS with longer polysaccharide chains. Collectively, these results suggested that group IA K LPS is also synthesized by a Rol-dependent pathway and that the typically short oligosaccharide K LPS results from the absence of Rol activity in these strains.

show abstract

Section: Discussionmentioning

confidence: 99%

Distribution of the rol gene encoding the regulator of lipopolysaccharide O-chain length in Escherichia coli and its influence on the expression of group I capsular K antigens

1996

View full text Add to dashboard Cite

show abstract

“…The O-Ag chain length was previously correlated with bacterial virulence in mice as well as resistance to phagocytosis, cationic peptides and iron (Burns & Hull, 1998;Joiner, 1985;Skurnik & Bengoechea, 2003). Furthermore, several studies have determined that in Salmonella the O-Ag is involved in resistance to the bactericidal activity of serum complement (Grossman et al, 1987;Joiner, 1985;Tomás et al, 1988). Murray et al (2005) reported enhanced survival of bacteria in serum when the VL O-Ag was increased by previous exposure to inactivated pig serum or iron limitation; however, this effect could not be correlated with change in the expression of the wzz fepE gene.…”

Section: Introductionmentioning

confidence: 97%

“…The modal distribution of O-Ag chain lengths is controlled by the products of two genes, wzz st (also known as cld or rol) and wzz fepE , which confer to the O-Ag chain the feature to be long (L) or very long (VL), respectively (Morona et al, 1995;Murray et al, 2003;Raetz & Whitfield, 2002). The O-Ag chain length was previously correlated with bacterial virulence in mice as well as resistance to phagocytosis, cationic peptides and iron (Burns & Hull, 1998;Joiner, 1985;Skurnik & Bengoechea, 2003). Furthermore, several studies have determined that in Salmonella the O-Ag is involved in resistance to the bactericidal activity of serum complement (Grossman et al, 1987;Joiner, 1985;Tomás et al, 1988).…”

Section: Introductionmentioning

confidence: 99%

The PmrA/PmrB regulatory system controls the expression of the wzzfepE gene involved in the O-antigen synthesis of Salmonella enterica serovar Typhimurium

et al. 2011

View full text Add to dashboard Cite

The degree of polymerization of O-antigen from Salmonella enterica serovar Typhimurium is controlled by the products of the wzzs t and wzzfepE genes. In the present study we investigated the role of the PmrA/PmrB regulatory system in wzzfepE transcription. We report that the direct binding of the PmrA regulator to a specific promoter site induces the expression of the wzzfepE gene. This effect increases the amount of very long (VL) O-antigen, which is required for the resistance of Salmonella to serum human complement and polymyxin B, and for the replication of the bacteria within macrophages. The results obtained here highlight functional differences between WzzfepE and Wzzst, although the genes for both proteins are regulated in a PmrA-dependent way.

show abstract

“…Genetic (63) and chemical (26) data indicate that D-galactan I is attached to lipid A-core, with D-galactan II attached to the distal end of a proportion of available D-galactan I chains. LPS O polysaccharides may contribute to the virulence of a bacterium by enabling the bacterium to resist serum killing (18,56). D-Galactan II is responsible for the serum resistance of K. pneumoniae O1 (34,63).…”

mentioning

confidence: 99%

Relationships between rfb gene clusters required for biosynthesis of identical D-galactose-containing O antigens in Klebsiella pneumoniae serotype O1 and Serratia marcescens serotype O16

1995

View full text Add to dashboard Cite

The lipopolysaccharide O antigens of Klebsiella pneumoniae serotype O1 and Serratia marcescens serotype O16 both contain a repeating unit disaccharide of [33)-␤-D-Galf-(133)-␣-D-Galp-(13]; the resulting polymer is known as D-galactan I. In K. pneumoniae serotype O1, the genes responsible for the synthesis of D-galactan I are found in the rfb gene cluster (rfb KpO1 ). We report here the cloning and analysis of the rfb cluster from S. marcescens serotype O16 (rfb SmO16 ). This is the first rfb gene cluster examined for the genus Serratia. Synthesis of D-galactan I is an rfe-dependent process for both K. pneumoniae serotype O1 and S. marcescens serotype O16. Hybridization experiments with probes derived from each of the six rfb KpO1 genes indicate that the cloned rfb SmO16 cluster contains homologous genes arranged in the same order. However, the degree of homology at the nucleotide sequence level was sufficiently low that hybridization was detected only under low-stringency conditions. rfbAB SmO16 genes were subcloned and shown to encode an ABC-2 (ATP-binding cassette) transporter which is functionally identical to the one encoded by the corresponding rfb genes from K. pneumoniae serotype O1. The amino acid sequences of the predicted RfbA and RfbB homologs showed identities of 75.7% (87.9% total similarity) and 78.0% (86.5% total similarity), respectively. The last gene of the rfb KpO1 cluster, rfbF KpO1 , encodes a bifunctional galactosyltransferase which initiates the formation of D-galactan I. RfbF KpO1 and RfbF SmO16 are 57.6% identical (with 71.1% total similarity), and both show similarity with RfpB, the galactosyltransferase involved in the synthesis of Shigella dysenteriae type I O-polysaccharide. The G؉C contents of the rfbAB genes from each organism are quite similar, and values are lower than those typical for the species. However, the G؉C content of rfbF SmO16 (47.6%) was much higher than that of rfbF KpO1 (37.3%), despite the fact that the average for each species (52 to 60%) falls within the same range.Lipopolysaccharide (LPS) is located in the outer leaflet of gram-negative bacteria and is responsible for the biological activity of endotoxin. In enteric bacteria, this molecule consists of three regions: lipid A, the core oligosaccharide, and the O polysaccharide. Lipid A forms the outer leaflet of the outer membrane bilayer. The core oligosaccharide region is attached to lipid A, and the O polysaccharide extends outward from the core region. O polysaccharides are composed of repeating oligosaccharide units with variable numbers of sugar residues. There is extensive structural diversity within O polysaccharides (22, 64). The composition, sequence, linkage, and substitution of the individual monomer residues within a repeating unit is characteristic for a given LPS and the parental bacterial strain. Thus, the O polysaccharide gives rise to epitopes (O antigens) which contribute to the immunological specificity of LPS.Klebsiella pneumoniae serotype O1 produces a high-molecular-weight smooth LPS (S-LPS)...

show abstract

Studies on the Mechanism of Bacterial Resistance to Complement-Mediated Killing and on the Mechanism of Action of Bactericidal Antibody

Cited by 52 publications

References 95 publications

Distribution of the rol gene encoding the regulator of lipopolysaccharide O-chain length in Escherichia coli and its influence on the expression of group I capsular K antigens

Distribution of the rol gene encoding the regulator of lipopolysaccharide O-chain length in Escherichia coli and its influence on the expression of group I capsular K antigens

The PmrA/PmrB regulatory system controls the expression of the wzzfepE gene involved in the O-antigen synthesis of Salmonella enterica serovar Typhimurium

Relationships between rfb gene clusters required for biosynthesis of identical D-galactose-containing O antigens in Klebsiella pneumoniae serotype O1 and Serratia marcescens serotype O16

Contact Info

Product

Resources

About