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At least 937 records · Page 52Linked to original sources
PubMed1975

3-Deoxy-2-octulosonic acid 5-phosphate: a component of the endotoxin of Bordetella pertussis.

Upon hydrolysis with 2 N hydrochloric acid for 2 h, a 3-deoxy-octulosonic acid 5-phosphate was released from the endotoxin of Bordetella pertussis. The structure of the compound was established through chemical degradation. By periodate treatment of the intact endotoxin it was shown that positions 7 and 8 of the bound octulosonic acid phosphate were free, which, if present in a cyclic form, must be a pyranoside.

Bordetella pertussis↗
PubMed1975

Heterogeneity of lipopolysaccharides. Analysis of polysaccharide chain lengths by sodium dodecylsulfate-polyacrylamide gel electrophoresis.

Lipopolysaccharide preparations from R(rough) Escherichia coli O8-,SR(semirough) Salmonella typhimurium and S (smooth) strains E. coli O8 and Citrobacter 396 were disintegrated with sodium dodecylsulfate and subjected to polyacrylamide gel electrophoresis in the presence of 1% sodium dodecylsulfate. The results obtained were compared with those obtained from the same lipopolysaccharide preparations by degradation analysis. In dodecylsulfate gel electrophoresis the lipopolysaccharide preparation from the E. coli R mutant and the S. typhimurium SR mutant showed one band each (R-and SR-band, respectively) with different electrophoretic mobilities. The lipopolysaccharide preparations from the E. coli O8-strain exhibited two bands, one of which had the same electrophoretic mobility as the R-band and the other was identified as S-band. The lipopolysaccharide preparation from the Citrobacter 396-S-strain exhibited four bands: one R-band, one SR-band and two S-bands. The results showed that wild-type S strains contain more than one type of lipopolysaccharide. They differ in the length of their O-specific polysaccharide chains. The lipid A content of the different lipopolysaccharide was expressed in their electrophoretic mobilities.

Citrobacter↗
PubMed1976

Cell-wall lipopolysaccharides of ampicillin-resistant mutants of Escherichia coli K-12.

The lipopolysaccharides of ampicillin-resistant cell-wall-defective mutants of Escherichia coli K-12 were analyzed. From their lipopolysaccharides the respective core oligosaccharides were obtained. Following dephosphorylation,the core oligosaccharides were methylated and analyzed by gas chromatography/mass spectrometry. From core-defective mutants substructures of the K-12 core were obtained. Analysis of the lipopolysaccharide preparations from wild-type K-12 indicated the presence of several core structures with different degrees of completion. The lipopolysaccharide preparation was degraded and the oligosaccharide mixture was partially resolved by gel filtration chromatography. Methylation, gas chromatography and mass spectrometry of the oligosaccharides permitted the tentative formulation of the K-12 core structure. Alternative interpretations for this heterogeneity are discussed.

Ampicillin↗
PubMed1997

Analysis of the icsBA locus required for biosynthesis of the inner core region from Neisseria meningitidis lipopolysaccharide.

By deletion mutagenesis in the entire meningococcal chromosome, we have previously identified the icsA gene, which encodes the glycosyltransferase required for adding GlcNAc to Hep-II in the inner core of meningococcal LPS. This gene has homology to several LPS glycosyltransferases, notably to rfaK from Salmonella typhimurium and bplH from Bordetella pertussis, both of which encode GlcNAc transferases. Directly upstream of icsA is an ORF showing significant homology to the hypothetical protein HI0653 from the Haemophilus influenzae genome sequence, and to a lesser degree to putative glycosyltransferases from Streptococcus thermophilus and Yersinia enterocolitica. Insertional inactivation of this ORF resulted in a meningococcal strain with truncated LPS. We have named this new LPS-involved gene icsB. Differences in binding of monoclonal antibodies and in mobility on Tricine-SDS-PAGE showed that LPS from icsA and icsB mutants is similar but not identical. On the basis of these results, we postulated that the new gene encodes the glycosyltransferase required for adding Glc to Hep-I. Structural analysis of purified mutant LPS by electrospray mass spectrometry was used to verify this hypothesis. The composition determined for icsA and icsB is lipidA-(KDO)2-(Hep)2.PEA and lipidA-(KDO)2-(Hep)2.PEA-GlcNAc, respectively. The icsA and icsB genes thus form an operon encoding the glycosyltransferases required for chain elongation from the lipidA-(KDO)2-(Hep)2 basal structure, with IcsA first adding GlcNAc to Hep-II and IcsB subsequently adding Glc to Hep-I. Only then is completion of the lacto-N-neotetraose structure possible through the action of the IgtA-E genes.

Acetylglucosamine↗