Chemical Synthesis of the Repeating Unit of Type II Group B Streptococcus Capsular Polysaccharide

2018 ◽  
Vol 83 (11) ◽  
pp. 5920-5930 ◽  
Author(s):  
Liming Shao ◽  
Han Zhang ◽  
Yaoyao Li ◽  
Guofeng Gu ◽  
Feng Cai ◽  
...  
Keyword(s):  
Chemical Synthesis ◽  
Capsular Polysaccharide ◽  
Group B Streptococcus ◽  
Type Ii ◽  
Group B

scholarly journals Chemical Synthesis of the Repeating Unit of Type Ia Group B Streptococcus Capsular Polysaccharide

2015 ◽  
Vol 17 (5) ◽  
pp. 1102-1105 ◽  
Author(s):  
Prolay K. Mondal ◽  
Guochao Liao ◽  
Mohabul A. Mondal ◽  
Zhongwu Guo
Keyword(s):  
Chemical Synthesis ◽  
Capsular Polysaccharide ◽  
Group B Streptococcus ◽  
Type Ia ◽  
Group B

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 Seroepidemiology of group B streptococcus type II antibody specificity

1988 ◽  
Vol 101 (2) ◽  
pp. 347-354 ◽  
Author(s):  
B. M. Gray ◽  
D. G. Pritchard ◽  
J. D. Springfield ◽  
R. J. Benak ◽  
H. C. Dillon
Keyword(s):  
Sialic Acid ◽  
Antibody Level ◽  
Specific Antibody ◽  
Group B Streptococcus ◽  
Antibody Specificity ◽  
Type Ii ◽  
Elisa System ◽  
Human Antibodies ◽  
Group B

SUMMARYThe specificity of human antibodies for the two major sidechain determinants of the type II group B streptococcal (GBS) polysaccharide was examined in 90 pairs of maternal and cord sera. Using an ELISA system, total antibody was measured against the complete (sialylated) type II antigen and the proportion of antibody against the galactose determinant was estimated by inhibition with free β–methylgalactopyranosided. Mothers colonized by type II or by other GBS types had higher levels of total specific antibody (means, 33 and 4–7 µg/ml, respectively) than those not colonized (mean, 2–2 µg/ml). Cord sera averaged 1–2 µg/ml lower than maternal sera. Colonization with GBS was also associated with higher levels against the galactose determinant (mean, 1.5&µg/ml, compared to 0–7µg/ml for those not colonized). The distribution of specificities favoured antibodies against the sialic acid determinant in maternal but not cord sera. Specificity as well as antibody level may play a role in the epidemiology of GBS type II.

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