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

ABSTRACT Group B Streptococcus (GBS) is the leading cause of bacterial sepsis and meningitis among neonates. While the capsular polysaccharide (CPS) is an important virulence factor of GBS, other cell surface components, such as C proteins, may also play a role in GBS disease. CPS production by GBS type III strain M781 was greater when cells were held at a fast (1.4-h mass-doubling time [td ]) than at a slow (11-htd ) rate of growth. To further investigate growth rate regulation of CPS production and to investigate production of other cell components, different serotypes and strains of GBS were grown in continuous culture in a semidefined and a complex medium. Samples were obtained after at least five generations at the selected growth rate. Cells and cell-free supernatants were processed immediately, and results from all assays were normalized for cell dry weight. All serotypes (Ia, Ib, and III) and strains (one or two strains per serotype) tested produced at least 3.6-fold more CPS at atd of 1.4 h than at atd of 11 h. Production of beta C protein by GBS type Ia strain A909 and type Ib strain H36B was also shown to increase at least 5.5-fold with increased growth rate (production at atd of 1.4 h versus 11 h). The production of alpha C protein by the same strains did not significantly change with increased growth rate. The effect of growth rate on other cell components was also investigated. Production of group B antigen did not change with growth rate, while alkaline phosphatase decreased with increased growth rate. Both CAMP factor and beta-hemolysin production increased fourfold with increased growth rate. Growth rate regulation is specific for select cell components in GBS, including beta C protein, alkaline phosphatase, beta-hemolysin, and CPS production.

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Construction of multivalent sialyl Lex from the type Ia group B Streptococcus capsular polysaccharide

Carbohydrate Research ◽

10.1016/s0008-6215(01)00098-2 ◽

2001 ◽

Vol 332 (3) ◽

pp. 249-255 ◽

Cited By ~ 2

Author(s):

Wei Zou ◽

JianJun Li ◽

Suzon Larocque ◽

Harold J Jennings

Keyword(s):

Capsular Polysaccharide ◽

Group B Streptococcus ◽

Sialyl Lex ◽

Type Ia ◽

Group B

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Structure determination ofStreptococcus suisserotype 14 capsular polysaccharide

Biochemistry and Cell Biology ◽

10.1139/bcb-2012-0036 ◽

2013 ◽

Vol 91 (2) ◽

pp. 49-58 ◽

Cited By ~ 27

Author(s):

Marie-Rose Van Calsteren ◽

Fleur Gagnon ◽

Cynthia Calzas ◽

Guillaume Goyette-Desjardins ◽

Masatoshi Okura ◽

...

Keyword(s):

Sialic Acid ◽

Capsular Polysaccharide ◽

Group B Streptococcus ◽

Periodate Oxidation ◽

Side Chain ◽

Chemically Modified ◽

Type Ia ◽

Group B ◽

Suis Serotype ◽

Mild Acid

The capsular polysaccharide (CPS) of Streptococcus suis serotype 14 was purified, chemically modified, and characterized. Sugar and absolute configuration analyses gave the following CPS composition: d-Gal, 3; d-Glc, 1; d-GlcNAc, 1; d-Neu5Ac, 1. The Sambucus nigra lectin, which recognizes the Neu5Ac(α2–6)Gal/GalNAc sequence, showed binding to the native CPS. Sialic acid was found to be terminal, and the CPS was quantitatively desialylated by mild acid hydrolysis. It was also submitted to periodate oxidation followed by borohydride reduction and Smith degradation. Sugar and methylation analyses,1H and13C nuclear magnetic resonance, and mass spectrometry of the native CPS or of its specifically modified products allowed to determine the repeating unit sequence: [6)[Neu5Ac(α2–6)Gal(β1–4)GlcNAc(β1–3)]Gal(β1–3)Gal(β1–4)Glc(β1–]n. S. suis serotype 14 CPS has an identical sialic acid-containing side chain as serotype 2 CPS, but differs by the absence of rhamnose in its composition. The same side chain is also present in group B Streptococcus type Ia CPS, except that in the latter sialic acid is 2,3- rather than 2,6-linked to the following galactose. A correlation between the S. suis CPS sequence and genes of the serotype 14 cps locus encoding putative glycosyltransferases and polymerase responsible for the biosynthesis of the repeating unit is proposed.

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