scholarly journals Development of an O-Antigen Serotyping Scheme forCronobacter sakazakii

2011 ◽  
Vol 77 (7) ◽  
pp. 2209-2214 ◽  
Author(s):  
Yamin Sun ◽  
Min Wang ◽  
Hongbo Liu ◽  
Jingjing Wang ◽  
Xin He ◽  
...  
Keyword(s):  
Fragment Length Polymorphism ◽  
Gene Clusters ◽  
Opportunistic Pathogen ◽  
Cronobacter Sakazakii ◽  
Bacterial Strains ◽  
Banding Patterns ◽  
O Antigen ◽  
Severe Infections ◽  
O Antigens ◽  
Restriction Fragment Length

ABSTRACTCronobacter sakazakiiis an opportunistic pathogen that can cause severe infections. Serotyping provides a basis for the categorization of bacterial strains and is an important tool for epidemiological and surveillance purposes. In this study, of the 135Cronobacterstrains tested initially, 119 were identified asC. sakazakiiand used. A serotyping scheme forC. sakazakiithat classifies strains based on their different O antigens was developed. Seven antisera that exhibited high agglutinin titers (>640) were produced. O2 and O6 antisera were specific for their homologous strains, O4 and O7 antisera gave heterologous titers with O1 and O6 antigens, respectively, and O1, O3, and O5 antisera cross-reacted with each other and require preabsorption with the other two antigens. All of these 119C. sakazakiistrains were clearly assigned to these seven serotypes. O1 and O2 are the dominant serotypes, comprising 69.7% of the isolates. We also characterized the O-antigen gene clusters using restriction fragment length polymorphism (RFLP). The grouping ofC. sakazakiistrains based on their RFLP banding patterns correlated well with the grouping of strains based on our serotyping scheme. The serotype scheme presented here could prove to be a useful tool for serotypingC. sakazakiiisolates.

scholarly journals Structure and genetics of Escherichia coli O antigens

2019 ◽  
Vol 44 (6) ◽  
pp. 655-683 ◽  
Author(s):  
Bin Liu ◽  
Axel Furevi ◽  
Andrei V Perepelov ◽  
Xi Guo ◽  
Hengchun Cao ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genetic Basis ◽  
Structural Diversity ◽  
Gene Clusters ◽  
Current Standard ◽  
E Coli ◽  
Antigen Gene ◽  
O Antigen ◽  
Or Groups ◽  
O Antigens

ABSTRACT Escherichia coli includes clonal groups of both commensal and pathogenic strains, with some of the latter causing serious infectious diseases. O antigen variation is current standard in defining strains for taxonomy and epidemiology, providing the basis for many serotyping schemes for Gram-negative bacteria. This review covers the diversity in E. coli O antigen structures and gene clusters, and the genetic basis for the structural diversity. Of the 187 formally defined O antigens, six (O31, O47, O67, O72, O94 and O122) have since been removed and three (O34, O89 and O144) strains do not produce any O antigen. Therefore, structures are presented for 176 of the 181 E. coli O antigens, some of which include subgroups. Most (93%) of these O antigens are synthesized via the Wzx/Wzy pathway, 11 via the ABC transporter pathway, with O20, O57 and O60 still uncharacterized due to failure to find their O antigen gene clusters. Biosynthetic pathways are given for 38 of the 49 sugars found in E. coli O antigens, and several pairs or groups of the E. coli antigens that have related structures show close relationships of the O antigen gene clusters within clades, thereby highlighting the genetic basis of the evolution of diversity.

scholarly journals Molecular and Genetic Analyses of the Putative Proteus O Antigen Gene Locus

2010 ◽  
Vol 76 (16) ◽  
pp. 5471-5478 ◽  
Author(s):  
Quan Wang ◽  
Agnieszka Torzewska ◽  
Xiaojuan Ruan ◽  
Xiaoting Wang ◽  
Antoni Rozalski ◽  
...  
Keyword(s):  
Fragment Length Polymorphism ◽  
Gene Clusters ◽  
Molecular Classification ◽  
Opportunistic Pathogens ◽  
Antigen Gene ◽  
O Antigen ◽  
Tract Infections ◽  
High Degree

ABSTRACT Proteus species are well-characterized opportunistic pathogens primarily associated with urinary tract infections (UTI) of humans. The Proteus O antigen is one of the most variable constituents of the cell surface, and O antigen heterogeneity is used for serological classification of Proteus isolates. Even though most Proteus O antigen structures have been identified, the O antigen locus has not been well characterized. In this study, we identified the putative Proteus O antigen locus and demonstrated this region's high degree of heterogeneity by comparing sequences of 40 Proteus isolates using PCR-restriction fragment length polymorphism (RFLP). This analysis identified five putative Proteus O antigen gene clusters, and the probable functions of these O antigen-related genes were proposed, based on their similarity to genes in the available databases. Finally, Proteus-specific genes from these five serogroups were identified by screening 79 strains belonging to the 68 Proteus O antigen serogroups. To our knowledge, this is the first molecular characterization of the putative Proteus O antigen locus, and we describe a novel molecular classification method for the identification of different Proteus serogroups.

scholarly journals Genetic Analysis of the Cronobacter sakazakii O4 to O7 O-Antigen Gene Clusters and Development of a PCR Assay for Identification of All C. sakazakii O Serotypes

2012 ◽  
Vol 78 (11) ◽  
pp. 3966-3974 ◽  
Author(s):  
Yamin Sun ◽  
Min Wang ◽  
Quan Wang ◽  
Boyang Cao ◽  
Xin He ◽  
...  
Keyword(s):  
Gene Clusters ◽  
Cronobacter Sakazakii ◽  
Pcr Assay ◽  
Gram Negative ◽  
Content Type ◽  
Antigen Gene ◽  
O Antigen ◽  
Multiplex Pcr Assay ◽  
Food Borne ◽  
Invasive Infections

ABSTRACTThe Gram-negative bacteriumCronobacter sakazakiiis an emerging food-borne pathogen that causes severe invasive infections in neonates. Variation in the O-antigen lipopolysaccharide in the outer membrane provides the basis for Gram-negative bacteria serotyping. The O-antigen serotyping scheme forC. sakazakii, which includes seven serotypes (O1 to O7), has been recently established, and the O-antigen gene clusters and specific primers for threeC. sakazakiiserotypes (O1, O2, and O3) have been characterized. In this study, theC. sakazakiiO4, O5, O6, and O7 O-antigen gene clusters were sequenced, and gene functions were predicted on the basis of homology.C. sakazakiiO4 shared a similar O-antigen gene cluster withEscherichia coliO103. The general features and anomalies of all sevenC. sakazakiiO-antigen gene clusters were evaluated and the relationship between O-antigen structures and their gene clusters were investigated. Serotype-specific genes for O4 to O7 were identified, and a molecular serotyping method for allC. sakazakiiO serotypes, a multiplex PCR assay, was developed by screening against 136 strains ofC. sakazakiiand closely related species. The sensitivity of PCR-based serotyping method was determined to be 0.01 ng of genomic DNA and 103CFU of each strain/ml. This study completes the elucidation ofC. sakazakiiO-antigen genetics and provides a molecular method suitable for the identification ofC. sakazakiiO1 to O7 strains.

O-antigen structure and gene clusters of Escherichia coli O51 and Salmonella enterica O57; another instance of identical O-antigens in the two species

2011 ◽  
Vol 346 (6) ◽  
pp. 828-832 ◽  
Author(s):  
Andrei V. Perepelov ◽  
Bin Liu ◽  
Sof’ya N. Senchenkova ◽  
Dan Guo ◽  
Sergei D. Shevelev ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Gene Clusters ◽  
O Antigen ◽  
O Antigens ◽  
Antigen Structure

scholarly journals Identification of the Pseudomonas aeruginosa O17 and O15 O-Specific Antigen Biosynthesis Loci Reveals an ABC Transporter-Dependent Synthesis Pathway and Mechanisms of Genetic Diversity

2020 ◽  
Vol 202 (19) ◽  
Author(s):  
Steven M. Huszczynski ◽  
Youai Hao ◽  
Joseph S. Lam ◽  
Cezar M. Khursigara
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Abc Transporter ◽  
Specific Antigen ◽  
Opportunistic Pathogen ◽  
Content Type ◽  
O Antigen ◽  
O Antigens ◽  
Dependent Pathway

ABSTRACT Many bacterial cell surface glycans, such as the O antigen component of lipopolysaccharide (LPS), are produced via the so-called Wzx/Wzy- or ABC transporter-dependent pathways. O antigens are highly diverse polysaccharides that protect bacteria from their environment and engage in important host-pathogen interactions. The specific structure and composition of O antigens are the basis of classifying bacteria into O serotypes. In the opportunistic pathogen Pseudomonas aeruginosa, there are currently 20 known O-specific antigen (OSA) structures. The clusters of genes responsible for 18 of these O antigens have been identified, all of which follow the Wzx/Wzy-dependent pathway and are located at a common locus. In this study, we located the two unidentified O antigen biosynthesis clusters responsible for the synthesis of the O15 and the O17 OSA structures by analyzing published whole-genome sequence data. Intriguingly, these clusters were found outside the conserved OSA biosynthesis locus and were likely acquired through multiple horizontal gene transfer events. Based on data from knockout and overexpression studies, we determined that the synthesis of these O antigens follows an ABC transporter-dependent rather than a Wzx/Wzy-dependent pathway. In addition, we collected evidence to show that the O15 and O17 polysaccharide chain lengths are regulated by molecular rulers with distinct and variable domain architectures. The findings in this report are critical for a comprehensive understanding of O antigen biosynthesis in P. aeruginosa and provide a framework for future studies. IMPORTANCE P. aeruginosa is a problematic opportunistic pathogen that causes diseases in those with compromised host defenses, such as those suffering from cystic fibrosis. This bacterium produces a number of virulence factors, including a serotype-specific O antigen. Here, we identified and characterized the gene clusters that produce the O15 and O17 O antigens and show that they utilize a pathway for synthesis that is distinct from that of the 18 other known serotypes. We also provide evidence that these clusters have acquired mutations in specific biosynthesis genes and have undergone extensive horizontal gene transfer within the P. aeruginosa population. These findings expand on our understanding of O antigen biosynthesis in Gram-negative bacteria and the mechanisms that drive O antigen diversity.

scholarly journals Structure of the O-antigen of Salmonella O66 and the genetic basis for similarity and differences between the closely related O-antigens of Escherichia coli O166 and Salmonella O66

Microbiology ◽  
2010 ◽  
Vol 156 (6) ◽  
pp. 1642-1649 ◽  
Author(s):  
Bin Liu ◽  
Andrei V. Perepelov ◽  
Dan Li ◽  
Sof'ya N. Senchenkova ◽  
Yanfang Han ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Gene Clusters ◽  
Coding Region ◽  
E Coli ◽  
Antigen Gene ◽  
O Antigen ◽  
New Genes ◽  
O Antigens ◽  
Antigen Structure

O-antigen is a component of the outer membrane of Gram-negative bacteria and is one of the most variable cell surface constituents, leading to major antigenic variability. The O-antigen forms the basis for bacterial serotyping. In this study, the O-antigen structure of Salmonella O66 was established, which differs from the known O-antigen structure of Escherichia coli O166 only in one linkage (most likely the linkage between the O-units) and O-acetylation. The O-antigen gene clusters of Salmonella O66 and E. coli O166 were found to have similar organizations, the only exception being that in Salmonella O66, the wzy gene is replaced by a non-coding region. The function of the wzy gene in E. coli O166 was confirmed by the construction and analysis of deletion and trans-complementation mutants. It is proposed that a functional wzy gene located outside the O-antigen gene cluster is involved in Salmonella O66 O-antigen biosynthesis, as has been reported previously in Salmonella serogroups A, B and D1. The sequence identity for the corresponding genes between the O-antigen gene clusters of Salmonella O66 and E. coli O166 ranges from 64 to 70 %, indicating that they may originate from a common ancestor. It is likely that after the species divergence, Salmonella O66 got its specific O-antigen form by inactivation of the wzy gene located in the O-antigen gene cluster and acquisition of two new genes (a wzy gene and a prophage gene for O-acetyl modification) both residing outside the O-antigen gene cluster.

scholarly journals Sequence Analysis of Four Shigella boydii O-Antigen Loci: Implication for Escherichia coli andShigella Relationships

2001 ◽  
Vol 69 (11) ◽  
pp. 6923-6930 ◽  
Author(s):  
Lei Wang ◽  
Wenjia Qu ◽  
Peter R. Reeves
Keyword(s):  
Escherichia Coli ◽  
Gene Clusters ◽  
Shigella Dysenteriae ◽  
E Coli ◽  
Shigella Boydii ◽  
Antigen Gene ◽  
O Antigen ◽  
Atypical Features ◽  
Serotype 5 ◽  
O Antigens

ABSTRACT Shigella strains are in reality clones ofEscherichia coli and are believed to have emerged relatively recently (G. M. Pupo, R. Lan, and P. R. Reeves, Proc. Natl. Acad. Sci. USA 97:10567–10572, 2000). There are 33 O-antigen forms in these Shigella clones, of which 12 are identical to O antigens of other E. coli strains. We sequenced O-antigen gene clusters from Shigella boydiiserotypes 4, 5, 6, and 9 and also studied the O53- and O79-antigen gene clusters of E. coli, encoding O antigens identical to those of S. boydii serotype 4 and S. boydii serotype 5, respectively. In both cases the S. boydii and E. coli O-antigen gene clusters have the same genes and organization. The clusters of both S. boydii 6 and S. boydii 9 O antigens have atypical features, with a functional insertion sequence and a wzx gene located in the orientation opposite to that of all other genes in S. boydii serotype 9 and an rmlC gene located away from other rml genes in S. boydii serotype 6. Sequences of O-antigen gene clusters from another threeShigella clones have been published, and two of them also have abnormal structures, with either the entire cluster or one gene being located on a plasmid in Shigella sonnei orShigella dysenteriae, respectively. It appears that a high proportion of clusters coding for O antigens specific toShigella clones have atypical features, perhaps indicating recent formation of these gene clusters.

scholarly journals Genetic Similarity Among Brassica oleracea L. Genotypes as Measured by Restriction Fragment Length Polymorphisms

1993 ◽  
Vol 118 (2) ◽  
pp. 298-303 ◽  
Author(s):  
James Nienhuis ◽  
Mary K. Slocum ◽  
Dawn A. DeVos ◽  
Roger Muren
Keyword(s):  
Brassica Oleracea ◽  
Restriction Fragment ◽  
Fragment Length ◽  
Genetic Similarity ◽  
Fragment Length Polymorphism ◽  
Pedigree Information ◽  
Banding Patterns ◽  
Length Polymorphisms ◽  
Wide Range ◽  
Restriction Fragment Length

Genetic similarities were calculated among 89 Brassica oleracea L. genotypes, which included 62 broccolis (var. italica), 16 cauliflowers (var. botrytis), and 11 cabbages (var. capitata). These entries represented a wide range of commercially available germplasm, including open-pollinated cultivars, commercial hybrids, the inbred parents of several hybrid cultivars, and 27 entries that were provided as unknowns. Sixteen random genomic clones were used as probes in Southern hybridizations to detect restriction fragment length polymorphism (RFLP). From each of the random probes, an average of four polymorphic bands were classified as to their presence or absence for each genotype. The genetic similarity between ail pairs of genotypes was calculated. A multidimensional scaling (MDS) plot indicated that the broccoli, cauliflower, and cabbage groups were clustered with very little overlap. Within groups, genetic similarity corresponded to relationships based on available pedigree information. Comparison of banding patterns between hypothetical and actual hybrids was used to correctly identify the parents of several parent-hybrid combinations. The RFLP pattern of a hybrid and one of the parents (female) were used to predict the genotype and identity of the other parent (male).

scholarly journals Species Identification of Mycobacteria by PCR-Restriction Fragment Length Polymorphism of therpoB Gene

2000 ◽  
Vol 38 (8) ◽  
pp. 2966-2971 ◽  
Author(s):  
Hyeyoung Lee ◽  
Hee-Jung Park ◽  
Sang-Nae Cho ◽  
Gill-Han Bai ◽  
Sang-Jae Kim
Keyword(s):  
Restriction Fragment Length Polymorphism ◽  
Restriction Fragment ◽  
Length Polymorphism ◽  
Fragment Length ◽  
Fragment Length Polymorphism ◽  
Species Level ◽  
Polymorphism Analysis ◽  
Mycobacterial Species ◽  
Bacterial Strains ◽  
Restriction Fragment Length

PCR-restriction fragment length polymorphism analysis (PRA) using the novel region of the rpoB gene was developed for rapid and precise identification of mycobacteria to the species level. A total of 50 mycobacterial reference strains and 3 related bacterial strains were used to amplify the 360-bp region of rpoB, and the amplified DNAs were subsequently digested with restriction enzymes such as MspI and HaeIII. The results from this study clearly show that most of the mycobacterial species were easily differentiated at the species level by this PRA method. In addition, species with several subtypes, such as Mycobacterium gordonae, M. kansasii, M. celatum, andM. fortuitum, were also differentiated by this PRA method. Subsequently, an algorithm was constructed based on the results, and a blinded test was carried out with more than 260 clinical isolates that had been identified on the basis of conventional tests. Comparison of these two sets of results clearly indicates that this new PRA method based on the rpoB gene is more simple, more rapid, and more accurate than conventional procedures for differentiating mycobacterial species.

scholarly journals Relationship of Yersinia pseudotuberculosis O Antigens IA, IIA, and IVB: the IIA Gene Cluster Was Derived from That of IVB

2002 ◽  
Vol 70 (6) ◽  
pp. 3271-3276 ◽  
Author(s):  
Elvia Pacinelli ◽  
Lei Wang ◽  
Peter R. Reeves
Keyword(s):  
Gene Cluster ◽  
Biosynthetic Pathway ◽  
Yersinia Pseudotuberculosis ◽  
Gene Clusters ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
O Antigen ◽  
O Antigens ◽  
Relationship Of ◽  
Six Genes

ABSTRACT O antigen is part of the lipopolysaccharide present in the outer membrane of gram-negative bacteria and is highly polymorphic. In this study, we obtained sequences of the O-antigen gene clusters for the Yersinia pseudotuberculosis antigens IA, IIA, and IVB. We propose that the IIA gene cluster was derived from the IVB cluster, one of the very few cases in which a parent gene cluster is identified, and that the IA gene cluster could be a hybrid of the IVB and IB gene clusters. All three O antigens contain 6-deoxy-d-mannoheptose, and we identified six genes for the biosynthetic pathway for the precursor of this sugar, GDP-6-deoxy-d-mannoheptose.

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