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Abstract h. guo, l. feng, j. tao, c. zhang and l. wang. 2004.Aim: To characterize the locus for O-antigen biosynthesis from Escherichia coli O172 type strain and to develop a rapid, specific and sensitive PCR-based method for identification and detection of E. coli O172. Methods and Results: DNA of O-antigen gene cluster of E. coli O172 was amplified by long-range PCR method using primers based on housekeeping genes galF and gnd Shot gun bank was constructed and high quality sequencing was performed. The putative genes for synthesis of UDP-FucNAc, O-unit flippase, O-antigen polymerase and glycosyltransferases were assigned by the homology search. The evolutionary relationship between O-antigen gene clusters of E. coli O172 and E. coli O26 is shown by sequence comparison. Genes specific to E. coli O172 strains were identified by PCR assays using primers based on genes for O-unit flippase, O-antigen polymerase and glycosyltransferases. The specificity of PCR assays was tested using all E. coli and Shigella O-antigen type strains, as well as 24 clinical E. coli isolates. The sensitivity of PCR assays was determined, and the detection limits were 1 pg microl(-1) chromosomal DNA, 0.2 CFU g(-1) pork and 0.2 CFU ml(-1) water. The total time required from beginning to end of the procedure was within 16 h. Conclusion: The O-antigen gene cluster of E. coli O172 was identified and PCR assays based on O-antigen specific genes showed high specificity and sensitivity. Significance and Impact of the Study: An O-antigen gene cluster was identified by sequencing. The specific genes were determined for E. coli O172. The sensitivity of O-antigen specific PCR assay was tested. Although Shiga toxin-producing O172 strains were not yet isolated from clinical specimens, they may emerge as pathogens

Molecular typing, Escherichia coli O172, O-antigen gene cluster, specific genes, STEC

NCBI PubMed ID: 15186455
Journal NLM ID: 9706280
Publisher: Oxford: Blackwell Publishing for the Society for Applied Bacteriology
Correspondence: wanglei@nankai.edu.cn
Institutions: TEDA School of Biological Sciences and Biotechnology, Tianjin State Laboratory of Microbial Functional Genomics, Nankai University, TEDA, Tianjin, China

An O-polysaccharide was isolated by mild acid degradation of the lipopolysaccharide of Proteus vulgaris O42 and studied by sugar and methylation analyses along with 1H, 13C and 31P NMR spectroscopy. The following structure of the polysaccharide having a linear pentasaccharide phosphate repeating unit was established:

Lipopolysaccharide, O-antigen, NMR spectroscopy, Proteus vulgaris, bacterial polysaccharide structure, Glucosyl phosphate

NCBI PubMed ID: 17936254
Journal NLM ID: 0043535
Publisher: Elsevier
Correspondence: perepel@ioc.ac.ru
Institutions: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia,Department of Immunobiology of Bacteria, Institute of Microbiology and Immunology, Lodz, Poland
Methods: 13C NMR, 1H NMR, methylation, GLC-MS, NMR-2D, chemical analysis, 31P NMR, GLC, mild acid hydrolysis, NMR-1D, serological methods, alkaline hydrolysis

An anomeric phosphodiester linkage formed by a glycosyl phosphate unit and a hydroxyl group of another monosaccharide is found in many glycopolymers of the outer membrane in bacteria (e.g., capsular polysaccharides and lipopolysaccharides), yeasts and protozoa. The polymers (phosphoglycans) composed of glycosyl phosphate (or oligoglycosyl phosphate) repeating units could be chemically classified as poly(glycosyl phosphates). Their importance as immunologically active components of the cell wall and/or capsule of numerous microorganisms upholds the need to develop routes for the chemical preparation of these biopolymers. In this paper, we (1) present a review of the primary structures (known to date) of natural phosphoglycans from various sources, which contain glycosyl phosphate units, and (2) discuss different approaches and recent achievements in the synthesis of glycosyl phosphosaccharides and poly(glycosyl phosphates).

synthesis, structure, polysaccharides, Phosphoglycans, Anomeric phosphodiesters

NCBI PubMed ID: 17092493
Publication DOI: 10.1016/j.carres.2006.10.006
Journal NLM ID: 0043535
Publisher: Elsevier
Correspondence: a.v.nikolaev@dundee.ac.uk
Institutions: College of Life Sciences, Division of Biological Chemistry and Molecular Microbiology, University of Dundee, Dundee DD1 5EH, UK.