scholarly journals Serological Identification and Prevalence of a Novel O-Antigen Epitope Linked to 3- and 4-O-Acetylated Rhamnose III of Lipopolysaccharide in Shigella flexneri

2014 ◽  
Vol 52 (6) ◽  
pp. 2033-2038 ◽  
Author(s):  
J. Wang ◽  
R. Lan ◽  
Y. A. Knirel ◽  
X. Luo ◽  
S. N. Senchenkova ◽  
...  
Keyword(s):  
Shigella Flexneri ◽  
O Antigen ◽  
Serological Identification ◽  
Antigen Epitope

scholarly journals Molecular Modeling of the Shigella flexneri Serogroup 3 and 5 O-Antigens and Conformational Relationships for a Vaccine Containing Serotypes 2a and 3a

Vaccines ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 643
Author(s):  
Jason Hlozek ◽  
Sara Owen ◽  
Neil Ravenscroft ◽  
Michelle M. Kuttel
Keyword(s):  
Diarrheal Disease ◽  
Shigella Flexneri ◽  
Quadrivalent Vaccine ◽  
Slight Effect ◽  
Work Support ◽  
O Antigen ◽  
The Common ◽  
O Antigens ◽  
Chain Conformations ◽  
Shared Epitopes

The pathogenic bacterium Shigella flexneri is a leading global cause of diarrheal disease. The O-antigen is the primary vaccine target and distinguishes the 30 serotypes reported. Except for serotype 6, all S. flexneri serotypes have a common backbone repeating unit (serotype Y), with variations in substitution creating the various serotypes. A quadrivalent vaccine containing serotypes 2a and 3a (as well as 6 and Shigella sonnei) is proposed to provide broad protection against non-vaccine S. flexneri serotypes through shared epitopes and conformations. Here we model the O-antigen (O-Ag) conformations of serogroups 3 and 5: a continuation of our ongoing systematic study of the S. flexneri O-antigens that began with serogroup 2. Our simulations show that S. flexneri serogroups 2, 3, and 5 all have flexible O-Ags, with substitutions of the backbone altering the chain conformations in different ways. Our analysis suggests three general heuristics for the effects of substitution on the Shigella O-Ag conformations: (1) substitution on rhamnose C reduces the extension of the O-Ag chain; (2) substitution at O-3 of rhamnose A restricts the O-Ags to predominantly helical conformations, (3) substitution at O-3 of rhamnose B has only a slight effect on conformation. The common O-Ag conformations across serotypes identified in this work support the assumption that a quadrivalent vaccine containing serotypes 2a and 3a could provide coverage against S. flexneri serotype 3b and serogroup 5.

scholarly journals A Novel Glucosyltransferase Involved in O-Antigen Modification of Shigella flexneri Serotype 1c

2009 ◽  
Vol 191 (21) ◽  
pp. 6612-6617 ◽  
Author(s):  
Robert M. Stagg ◽  
Swee-Seong Tang ◽  
Nils I. A. Carlin ◽  
Kaisar A. Talukder ◽  
Phung D. Cam ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Shigella Flexneri ◽  
Functional Expression ◽  
Transposon Mutagenesis ◽  
The Other ◽  
Bacterial Chromosome ◽  
Gene Encoding ◽  
O Antigen ◽  
Species Analysis

ABSTRACT The O antigen of serotype 1c differs from the unmodified O antigen of serotype Y by the addition of a disaccharide (two glucosyl groups) to the tetrasaccharide repeating unit. It was shown here that addition of the first glucosyl group is mediated by the previously characterized gtrI cluster, which is found within a cryptic prophage at the proA locus in the bacterial chromosome. Transposon mutagenesis was performed to disrupt the gene responsible for addition of the second glucosyl group, causing reversion to serotype 1a. Colony immunoblotting was used to identify the desired revertants, and subsequent sequencing, cloning, and functional expression successfully identified the gene encoding serotype 1c-specific O-antigen modification. This gene (designated gtrIC) was present as part of a three-gene cluster, similar to other S. flexneri glucosyltransferase genes. Relative to the other S. flexneri gtr clusters, the gtrIC cluster is more distantly related and appears to have arrived in S. flexneri from outside the species. Analysis of surrounding sequence suggests that the gtrIC cluster arrived via a novel bacteriophage that was subsequently rendered nonfunctional by a series of insertion events.

scholarly journals Bacteriophage-encoded glucosyltransferase GtrII of Shigella flexneri: membrane topology and identification of critical residues

2005 ◽  
Vol 389 (1) ◽  
pp. 137-143 ◽  
Author(s):  
Adele M. LEHANE ◽  
Haralambos KORRES ◽  
Naresh K. VERMA
Keyword(s):  
Sequence Similarity ◽  
Repeat Unit ◽  
Shigella Flexneri ◽  
Membrane Topology ◽  
Transmembrane Helices ◽  
O Antigen ◽  
Repeat Units ◽  
Related Group ◽  
Critical Residues ◽  
O Antigens

The Shigella flexneri serotypes differ in the nature of their O-antigens. The addition of glucosyl or O-acetyl groups to the common backbone repeat units gives rise to the different serotypes. GtrII glucosylates rhamnose III of the O-antigen repeat unit, thus converting serotype Y (which has no modifications to the basic O-antigen repeat unit) into serotype 2a, the most prevalent serotype. In the present study, the topology of GtrII has been determined. GtrII has nine transmembrane helices, a re-entrant loop and three large periplasmic regions. Four critical residues (Glu40, Phe414, Cys435 and Lys478) were identified in two of the periplasmic regions. Despite the lack of sequence similarity between GtrII and the Gtrs from other serotypes, three of the critical residues identified are conserved in the remaining Gtrs. This is consistent with some degree of mechanistic conservation in this functionally related group of proteins.

scholarly journals The normal chain length distribution of the O antigen is required for the interaction of Shigella flexneri 2a with polarized Caco-2 cells

2012 ◽  
Vol 45 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Anilei Hoare ◽  
Denisse Bravo ◽  
Mara Martinic ◽  
Miguel A Valvano ◽  
Inés Contreras ◽  
...  
Keyword(s):  
Chain Length ◽  
Shigella Flexneri ◽  
Length Distribution ◽  
Chain Length Distribution ◽  
O Antigen ◽  
Shigella Flexneri 2A

scholarly journals Molecular detection of all 34 distinct O-antigen forms of Shigella

2009 ◽  
Vol 58 (1) ◽  
pp. 69-81 ◽  
Author(s):  
Yayue Li ◽  
Boyang Cao ◽  
Bin Liu ◽  
Dan Liu ◽  
Qili Gao ◽  
...  
Keyword(s):  
Shigella Flexneri ◽  
Bacterial Species ◽  
Milk Powder ◽  
Shigella Dysenteriae ◽  
Detection Sensitivity ◽  
Clinical Samples ◽  
Shigella Boydii ◽  
O Antigen ◽  
Probe Concentration ◽  
O Antigens

Shigella is the cause of shigellosis or bacillary dysentery, the occurrence of which is estimated to be 165 million cases per year worldwide, resulting in 1.1 million deaths. Rapid and reliable assays for detecting and identifying Shigella in food, environmental and clinical samples are therefore necessary. Shigella species are traditionally identified by their O antigens. This study developed a DNA microarray targeting O-serotype-specific genes to detect all 34 distinct O-antigen forms of Shigella, including Shigella boydii types 1–18, Shigella dysenteriae types 1–13, Shigella flexneri types 1–5 and 6, and Shigella sonnei. A total of 282 strains were used to test the specificity of the microarray, including 186 Shigella and Escherichia coli representative strains, 86 Shigella clinical isolates and ten strains of other bacterial species that are commonly isolated from food or clinical stool specimens. The oligonucleotide probes were printed on the microarray in concentrations from 1 to 100 μM, and 10 μM proved to be the optimal probe concentration. The detection sensitivity for each serotype was 50 ng genomic DNA or 1 c.f.u. in 25 g milk powder sample following a 6 h enrichment in broth. The microarray is specific, sensitive and reproducible, and, to our knowledge, is the first report of a microarray for serotyping all O-antigen forms of Shigella.

Study of the structure of Shigella flexneri o antigen II. Physicochemical aspect

1970 ◽  
Vol 201 (2) ◽  
pp. 167-178 ◽  
Author(s):  
E. Hannecart-Pokorni ◽  
D. Dekegel ◽  
F. Depuydt ◽  
J. Dirkx
Keyword(s):  
Shigella Flexneri ◽  
Physicochemical Aspect ◽  
O Antigen
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