Escherichia coli L-19 isolated from a healthy individual did not agglutinate with any of 21 polyvalent antisera that cover 174 E. coli O-serogroups. The strain was studied in respect to the O-antigen (O-specific polysaccharide, OPS) structure and genetics. The LPS was isolated by phenol–water extraction of bacterial cells and cleaved by mild acid hydrolysis to yield the OPS. The OPS was studied by sugar and methylation analyses, along with 1D and 2D 1H and 13C NMR spectroscopy. The established structure of the linear tetrasaccharide repeating unit was found to be unique among known bacterial polysaccharide structures. A peculiar component of the L-19 OPS was an amide of glucuronic acid with 2-amino-1,3-propanediol (2-amino-2-deoxyglycerol) (GroN). The O-antigen gene cluster of L-19 between the conserved genes galF and gnd was sequenced, and gene functions were tentatively assigned by a comparison with sequences in the available databases and found to be in agreement with the OPS structure. Except for putative genes for synthesis and transfer of GroN, the sequences in the L-19 O-antigen gene cluster were little related to those of reference strains of the 174 known E. coli O-serogroups. The data obtained suggest that L-19 can be considered as a candidate for a new E. coli O-serogroup.
Received:
Accepted:
Published Online:
Funding
This study was supported by the:
Russian Science Foundation
(Award 14-14-01042)
National Key Program for Infectious Diseases of China
(Award 2013ZX10004216-001-001)
National 973 Program of China
(Award 2011CB504900 and 2013CB733904 )
International Science & Technology Cooperation Program of China
(Award 2013DFR30640 and 2012DFG31680)
National Natural Science Foundation of China (NSFC) Program
(Award 31270003, 31371259 and 31030002)
BastinD. A.,
ReevesP. R.(1995). Sequence and analysis of the O antigen gene (rfb) cluster of Escherichia coli O111. Gene 164:17–23 [View Article][PubMed]
ConradH. E.(1972). Methylation of carbohydrates with methyl iodide in dimethyl sulfoxide in the presence of methylsulfinyl-anion. Methods Carbohydr Chem 6:361–364
FengL.,
SenchenkovaS. N.,
YangJ.,
ShashkovA. S.,
TaoJ.,
GuoH.,
ZhaoG.,
KnirelY. A.,
ReevesP.,
WangL.(2004). Structural and genetic characterization of the Shigella boydii type 13 O antigen. J Bacteriol 186:383–392 [View Article][PubMed]
HolstO.(1999). Chemical structure of the core region of lipopolysaccharides. Endotoxin in Health and Disease115–154BradeH.,
OpalS. M.,
VogelS. N.,
MorrisonD. C.
New York: Marcel Dekker;
KarlyshevA. V.,
ChampionO. L.,
ChurcherC.,
BrissonJ. R.,
JarrellH. C.,
GilbertM.,
BrochuD.,
St MichaelF.,
LiJ.& other authors (2005). Analysis of Campylobacter jejuni capsular loci reveals multiple mechanisms for the generation of structural diversity and the ability to form complex heptoses. Mol Microbiol 55:90–103 [View Article][PubMed]
LandersjöC.,
WeintraubA.,
WidmalmG.(1996). Structure determination of the O-antigen polysaccharide from the enteroinvasive Escherichia coli (EIEC) O143 by component analysis and NMR spectroscopy. Carbohydr Res 291:209–216 [View Article][PubMed]
LeonteinK.,
LönngrenJ.(1993). Determination of the absolute configuration of sugars by gas-liquid chromatography of their acetylated 2-octyl glycosides. Methods Carbohydr Chem 9:87–89
LipkindG. M.,
ShashkovA. S.,
KnirelY. A.,
VinogradovE. V.,
KochetkovN. K.(1988). A computer-assisted structural analysis of regular polysaccharides on the basis of 13C-n.m.r. data. Carbohydr Res 175:59–75 [View Article][PubMed]
LiuB.,
KnirelY. A.,
FengL.,
PerepelovA. V.,
SenchenkovaS. N.,
WangQ.,
ReevesP. R.,
WangL.(2008). Structure and genetics of Shigella O antigens. FEMS Microbiol Rev 32:627–653 [View Article][PubMed]
SawardekerJ. S.,
SlonekerJ. H.,
JeanesA.(1965). Quantitative determination of monosaccharides as their alditol acetates by gas liquid chromatography. Anal Chem 37:1602–1604 [View Article]
ShashkovA. S.,
LipkindG. M.,
KnirelY. A.,
KochetkovN. K.(1988). Stereochemical factors determining the effects of glycosylation on the 13C chemical shifts in carbohydrates. Magn Reson Chem 26:735–747 [View Article]
WestphalO.,
JannK.(1965). Bacterial lipopolysaccharides. Extraction with phenol-water and further applications of the procedure. Methods Carbohydr Chem 5:83–91