scholarly journals Distinctive Features of Surface-Anchored Proteins of Streptococcus agalactiae Strains from Zimbabwe Revealed by PCR and Dot Blotting

2008 ◽  
Vol 15 (9) ◽  
pp. 1420-1424 ◽  
Author(s):  
Rooyen T. Mavenyengwa ◽  
Johan A. Maeland ◽  
Sylvester R. Moyo
Keyword(s):  
Potential Role ◽  
Capsular Polysaccharide ◽  
Group B Streptococcus ◽  
Potential Importance ◽  
Protein Markers ◽  
Distinctive Features ◽  
The Third ◽  
Group B ◽  
Type V ◽  
Dot Blotting

ABSTRACTThe distribution of capsular polysaccharide (CPS) types and subtypes (serovariants) among 121 group B streptococcus (GBS) strains from Zimbabwe was examined. PCR was used for the detection of both CPS types and the surface-anchored and strain-variable proteins Cα, Cβ, Alp1, Alp2, Alp3, R4/Rib, and Alp4. The R3 protein was detected by an antibody-based method using monoclonal anti-R3 antibody in dot blotting. The CPS types detected, Ia (15.7% of strains), Ib (11.6%), II (8.3%), III (38.8%), V (24.0%), and nontypeable (1.7%), were essentially as expected on the basis of data from Western countries. The type V strains showed distinctive features with respect to protein markers in that Alp3 was detected in only 6.9% of the isolates while R3 occurred in 75.9% and R4/Rib occurred in 37.9% of the isolates. R3 occurred nearly always in combination with one of the alpha-like (Alp) proteins, and it was the third most common of the proteins studied. These results show that type V GBS strains from Zimbabwe differed from type V strains from other geographical areas and also emphasize the importance of the R3 protein in GBS serotyping and its potential importance in the immunobiology of GBS, including a potential role in a future GBS vaccine.

scholarly journals Identification of novel cps locus polymorphisms in nontypable group B Streptococcus

2006 ◽  
Vol 55 (6) ◽  
pp. 775-783 ◽  
Author(s):  
Srinivas V. Ramaswamy ◽  
Patricia Ferrieri ◽  
Lawrence C. Madoff ◽  
Aurea E. Flores ◽  
Nikhil Kumar ◽  
...  
Keyword(s):  
Capsular Polysaccharide ◽  
Group B Streptococcus ◽  
Surface Protein ◽  
The Elderly ◽  
Surface Proteins ◽  
Pcr Analysis ◽  
Genetic Profile ◽  
Gene Encoding ◽  
Group B ◽  
Type V

Group B Streptococcus (GBS) is an important pathogen responsible for a variety of diseases in newborns and the elderly. A clinical GBS isolate is considered nontypable (NT) when serological methods fail to identify it as one of nine known GBS serotypes. Eight clinical isolates (designated A1–A4, B1–B4) showed PFGE profiles similar to that of a GBS serotype V strain expressing R1, R4 surface proteins. These unique isolates were further characterized by immunologic and genetic methods. Rabbit sera to isolates A1 and A2 reacted weakly with concentrated HCl extracts of A1–A4 isolates, but not with those of B1–B4 isolates. In addition, a type V capsular polysaccharide (CPS) inhibition ELISA revealed that cell wall extracts from isolates A1–A4, but not from B1–B4, expressed low but measurable amounts of type V CPS. Molecular serotyping with PCR analysis showed that all eight isolates contained a type V-specific CPS gene (cpsO) and harboured the gene encoding the surface protein Alp3. Multilocus sequence typing identified isolate A1 as belonging to a new sequence type (ST) designated ST-173, whereas the other seven isolates keyed to ST-1. Sequencing of the 18 genes (17 736 bp) in the cps locus showed that each NT isolate harboured one to three unique polymorphisms, and also identified an IS1381 element in cpsE of the B4 isolate. Collectively, genetic and immunologic analyses revealed that these NT isolates expressing R1, R4 proteins have a genetic profile consistent with that of type V, an emergent, antigenically diverse and increasingly prevalent GBS serotype.

Synthesis of a disialylated hexasaccharide of Type VIII Group B Streptococcus capsular polysaccharide

1999 ◽  
Vol 319 (1-4) ◽  
pp. 1-16 ◽  
Author(s):  
Eva Eichler ◽  
Harold J. Jennings ◽  
Michel Gilbert ◽  
Dennis M. Whitfield
Keyword(s):  
Capsular Polysaccharide ◽  
Group B Streptococcus ◽  
Type Viii ◽  
Group B

scholarly journals NeuA Sialic Acid O-Acetylesterase Activity Modulates O-Acetylation of Capsular Polysaccharide in Group B Streptococcus

2007 ◽  
Vol 282 (38) ◽  
pp. 27562-27571 ◽  
Author(s):  
Amanda L. Lewis ◽  
Hongzhi Cao ◽  
Silpa K. Patel ◽  
Sandra Diaz ◽  
Wesley Ryan ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Capsular Polysaccharide ◽  
Group B Streptococcus ◽  
Site Directed Mutagenesis ◽  
Synthetase Activity ◽  
Bacterial Surface ◽  
Acetylneuraminic Acid ◽  
Single Polypeptide ◽  
Group B

Group B Streptococcus (GBS) is a common cause of neonatal sepsis and meningitis. A major GBS virulence determinant is its sialic acid (Sia)-capped capsular polysaccharide. Recently, we discovered the presence and genetic basis of capsular Sia O-acetylation in GBS. We now characterize a GBS Sia O-acetylesterase that modulates the degree of GBS surface O-acetylation. The GBS Sia O-acetylesterase operates cooperatively with the GBS CMP-Sia synthetase, both part of a single polypeptide encoded by the neuA gene. NeuA de-O-acetylation of free 9-O-acetyl-N-acetylneuraminic acid (Neu5,9Ac2) was enhanced by CTP and Mg2+, the substrate and co-factor, respectively, of the N-terminal GBS CMP-Sia synthetase domain. In contrast, the homologous bifunctional NeuA esterase from Escherichia coli K1 did not display cofactor dependence. Further analyses showed that in vitro, GBS NeuA can operate via two alternate enzymatic pathways: de-O-acetylation of Neu5,9Ac2 followed by CMP activation of Neu5Ac or activation of Neu5,9Ac2 followed by de-O-acetylation of CMP-Neu5,9Ac2. Consistent with in vitro esterase assays, genetic deletion of GBS neuA led to accumulation of intracellular O-acetylated Sias, and overexpression of GBS NeuA reduced O-acetylation of Sias on the bacterial surface. Site-directed mutagenesis of conserved asparagine residue 301 abolished esterase activity but preserved CMP-Sia synthetase activity, as evidenced by hyper-O-acetylation of capsular polysaccharide Sias on GBS expressing only the N301A NeuA allele. These studies demonstrate a novel mechanism regulating the extent of capsular Sia O-acetylation in intact bacteria and provide a genetic strategy for manipulating GBS O-acetylation in order to explore the role of this modification in GBS pathogenesis and immunogenicity.

scholarly journals Transcriptional and Proteomic Profiles of Group B Streptococcus Type V Reveal Potential Adherence Proteins Associated with High-Level Invasion

2007 ◽  
Vol 75 (3) ◽  
pp. 1473-1483 ◽  
Author(s):  
Atul K. Johri ◽  
Immaculada Margarit ◽  
Mark Broenstrup ◽  
Cecilia Brettoni ◽  
Lei Hua ◽  
...  
Keyword(s):  
Surface Antigen ◽  
Binding Protein ◽  
Cell Mass ◽  
Group B Streptococcus ◽  
Penicillin Binding Protein ◽  
Ability To Act ◽  
Genomics And Proteomics ◽  
Group B ◽  
Type V

ABSTRACT Group B Streptococcus (GBS) is an opportunistic organism that can harmlessly colonize the human gut, vagina, and rectum but can also cause pneumonia, sepsis, and meningitis in neonates born to colonized mothers. We have shown previously that growth rate and oxygen level regulate the ability of GBS to invade eukaryotic cells in vitro. Herein we extend and expand on these observations to show that GBS type V, an emergent serotype, grown in a chemostat at a cell mass-doubling time (td ) of 1.8 h with oxygen invaded human ME-180 cervical epithelial cells in large numbers compared with those grown at the same td without oxygen or at a slower td of 11.0 h. The fact that several GBS type V cell wall-associated and membrane proteins were expressed exclusively under the invasive growth condition prompted an investigation, using genomics and proteomics, of all upregulated genes and proteins. Several proteins with potential roles in adherence were identified, including an undefined surface antigen (SAG1350), a lipoprotein (SAG0971), penicillin-binding protein 2b (SAG0765), glyceraldehyde-3-phosphate dehydrogenase (SAG0823), and an iron-binding protein (SAG1007). Mouse antisera to these five proteins inhibited binding of GBS type V to ME-180 cells by ≥85%. Recombinant undefined surface antigen (SAG1350), lipoprotein (SAG0971), and penicillin-binding protein 2b (SAG0765) each bound to ME-180 cells in a dose-dependent fashion, confirming their ability to act as ligands. Collectively, these data increase the number of potential GBS adherence factors and also suggest a role for these surface-associated proteins in initial pathogenic events.

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