Biosynthesis of Bacterial Polysaccharide Chains Composed of Repeating Units

Shibaev, V. N.

doi:10.1016/s0065-2318(08)60080-3

Cited by 118 publications

(61 citation statements)

References 411 publications

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“…It is known that oligosaccharides can function as signal molecules in plants (28). Furthermore, it has recently been shown that the product of the nod genes of R. meliloti is a sulfated and acylated oligosaccharide (21 (32). Also, some exo gene products may be involved in the export of polysaccharide from the periplasmic space, as was found for the K antigen genes of E. coli (17,29).…”

Section: Discussionmentioning

confidence: 92%

Regulation of Rhizobium meliloti exo genes in free-living cells and in planta examined by using TnphoA fusions

1991

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The exo loci of Rhizobium meliloti are necessary for the production of an acidic exopolysaccharide, EPS I, that is needed for alfalfa nodule invasion by strain RmlO21. We have isolated and characterized alkaline phosphatase fusions made with TnphoA in several exo loci of R. meliloti and used these fusions to examine the subcellular localization of exo gene products and the regulation of exo genes in free-living cells and in planta. In the course of this work, we isolated a new exo locus, exoT. We have obtained evidence that several of the exo loci may encode membrane proteins. The activity of TnphoA fusions in several exo loci is increased two-to fivefold in the presence of the regulatory mutations exoR95 and exoS96. While examining the regulation of the exo genes by exoR95 and exoS96, we found that certain classes of exo mutations are lethal in an exoR95 or exoS96 background unless a plasmid complementing the exo mutation is present. This result has possible implications for the role of these exo loci in EPS I biosynthesis. We have developed a method for staining nodules specifically for the alkaline phosphatase activity present in the inducing bacteria and used this method to show that an exoF::TnphoA fusion is expressed mainly in the invasion zone of the nodule.

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Section: Discussionmentioning

confidence: 92%

Regulation of Rhizobium meliloti exo genes in free-living cells and in planta examined by using TnphoA fusions

1991

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“…The ugd gene encodes UDPglucose dehydrogenase, which is responsible for the production of UDP-glucuronic acid. The K30 polysaccharide contains mannose, galactose, and glucuronic acid (14), and based on other bacterial systems, UDP-glucuronic acid is an expected biosynthetic precursor (40). The predicted Ugd protein from E. coli E69 is 388 amino acids in length and displays 86.6% amino acid similarity to KfiD from E. coli K5 (41) and 72.2% similarity to HasB from Streptococcus pyogenes (11).…”

Section: Resultsmentioning

confidence: 99%

Polymorphism, duplication, and IS1-mediated rearrangement in the chromosomal his-rfb-gnd region of Escherichia coli strains with group IA and capsular K antigens

1997

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Individual Escherichia coli strains produce several cell surface polysaccharides. In E. coli E69, the his region of the chromosome contains the rfb (serotype O9 lipopolysaccharide O-antigen biosynthesis) and cps (serotype K30 group IA capsular polysaccharide biosynthesis) loci. Polymorphisms in this region of the Escherichia coli chromosome reflect extensive antigenic diversity in the species. Previously, we reported a duplication of the manC-manB genes, encoding enzymes involved in GDP-mannose formation, upstream of rfb in strain E69 (P. Jayaratne et al., J. Bacteriol. 176:3126-3139, 1994). Here we show that one of the manC-manB copies is flanked by IS1 elements, providing a potential mechanism for the gene duplication. Adjacent to manB 1 on the IS1-flanked segment is a further open reading frame (ugd), encoding uridine-5 -diphosphoglucose dehydrogenase. The Ugd enzyme is responsible for the production of UDP-glucuronic acid, a precursor required for K30 antigen synthesis. Construction of a chromosomal ugd::Gm r insertion mutation demonstrated the essential role for Ugd in the biosynthesis of the K30 antigen and confirmed that there is no additional functional ugd copy in strain E69. PCR amplification and Southern hybridization were used to examine the distribution of IS1 elements and ugd genes in the vicinity of rfb in other E. coli strains, producing different group IA K antigens. The relative order of genes and, where present, IS1 elements was established in these strains. The regions adjacent to rfb in these strains are highly variable in both size and gene order, but in all cases where a ugd homolog was present, it was found near rfb. The presence of IS1 elements in the rfb regions of several of these strains provides a potential mechanism for recombination and deletion events which could contribute to the antigenic diversity seen in surface polysaccharides.

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“…GDP-mannose), and the polymeric chain extends at the nonreducing end [34]. This mechanism is believed to be widespread in strains of Escherichia coli and in related enteric bacteria and has been experimentally proven to exist in E. coli 0 8 and 0 9 strains [35,361.…”

Section: Discussionmentioning

confidence: 99%

The O‐Specific Polysaccharide Chain of Campylobacter fetus Serotype B Lipopolysaccharide is a d‐Rhamnan Terminated with 3‐O ‐Methyl‐d‐Rhamnose (d‐Acofriose)

Senchenkova

Shashkov

Knirel

et al. 1996

European Journal of Biochemistry

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An 0-specific polysaccharide was liberated from Cumpylnbucter fetus subsp. fetus serotype B lipopolysaccharide by mild acid hydrolysis followed by gel chromatography. This polysaccharide was found to contain D-rhamnose and 3-O-niethyl-~-rhamnose (~-Rha3Me, D-acofriose) in a ratio of approximately 24: 1 , as well as lipopolysaccharide core constituents. The structure of the polysaccharide was studied by 'H-NMR and "C-NMR spectroscopy, which included two-dimensional COSY, rotating-frame NOE spectroscopy (ROESY), and computer-assisted analysis of the "C-NMR spectrum. Methylation analysis using rH,Jmethyl iodide and Smith degradation followed by GLC/MS of the derived acetylated oligosaccharide-alditols was used to determine the location of D-acofrloSe. The 0-specific polysaccharide is linear, consists on average of 12 disaccharide repeating units, and is terminated by a residue of D-acofriose. The following structure of the D-rhamnan chain was established:Keywords: Cmipylohacter fetus ; lipopolysaccharide ; 0-specific polysaccharide ; D-rhamnose ; 3-0-methyl-D-rhainiiose.Campylobacfer fetus is a spiral, microaerophilic gram-negative bacterium that is a common pathogen of ungulates, and causes extraintestinal infections in imniunocomprornised humans, including bacteraeniia and septicaemia [I -31. There are two subspecies of C. jktus: C. ,fetus subsp. fetus, which is transmitted orally in faeces, and causes septic abortions in cattle and sheep; and C. fetus subsp. venerealis, which is transmitted venereally, and causes infertility in cattle [Z, 41.The lipopolysaccharide (LPS) of C. fetus is endotoxic 151 and forms the basis of the heat-stable antigen serotyping scheme of the bacterium [6]. Two main serotypes exist (A and B): C. jetus subsp. ,fetus strains belong to type A, whereas C. fetus subsp. verzerealis comprises both serotype A and B strains [7, 81. Biochemical tests can be applied to further differentiate between serotype A strains [7].Serological and electrophoretic analyses have shown that wild-type C. fetus strains produce high-molecular-mass LPS with 0-specific polysaccharide chains [6], and this can contribute to the resistance of strains to bactericidal activity of serum 19, 101. Serum-resistant strains also produce a crystalline surface array (Slayer) protein that is associated with virulence [I I ] and which is anchored to the bacterial surface by interaction with the 0-specific polysaccharide of C. Compositional analysis of C. fetus LPS has revealed the presence of rhamnose, fucose, Inannose, glucose, galactose, L-glycero-D-niunno-heptose, and D-gl?icero-D-munno-heptose in variable proportions in the different serotypes [14J. Nevertheless, despite the importance of LPS in serotyping and pathogenesis of C. fetus, no structural data on the 0-specific polysaccharide have been available to date. We now report that the structure of the 0-specific polysaccharide of C. fetus subsp. fetus serotype B is a D-rhamnan terminated with a D-acofrioSe residue. EXPERIMENTAL PROCEDURESBacterial growth, isolation of lipo...

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Biosynthesis of Bacterial Polysaccharide Chains Composed of Repeating Units

Cited by 118 publications

References 411 publications

Regulation of Rhizobium meliloti exo genes in free-living cells and in planta examined by using TnphoA fusions

Regulation of Rhizobium meliloti exo genes in free-living cells and in planta examined by using TnphoA fusions

Polymorphism, duplication, and IS1-mediated rearrangement in the chromosomal his-rfb-gnd region of Escherichia coli strains with group IA and capsular K antigens

The O‐Specific Polysaccharide Chain of Campylobacter fetus Serotype B Lipopolysaccharide is a d‐Rhamnan Terminated with 3‐O ‐Methyl‐d‐Rhamnose (d‐Acofriose)

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