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Host glycan sugar-specific pathways in Streptococcus pneumoniae: galactose as a key sugar in colonisation and infection [corrected].

Paixão L, Oliveira J, Veríssimo A, Vinga S, Lourenço EC, Ventura MR, Kjos M, Veening JW, Fernandes VE, Andrew PW, Yesilkaya H, Neves AR - PLoS ONE (2015)

Bottom Line: Therefore, it is reasonable to hypothesise that the pneumococcus would rely on these glycan-derived sugars to grow.Transcriptome analysis of cells grown on mucin showed specific upregulation of genes likely to be involved in deglycosylation, transport and catabolism of galactose, mannose and N acetylglucosamine.Our data pinpoint galactose as a key nutrient for growth in the respiratory tract and highlights the importance of central carbon metabolism for pneumococcal pathogenesis.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.

ABSTRACT
The human pathogen Streptococcus pneumoniae is a strictly fermentative organism that relies on glycolytic metabolism to obtain energy. In the human nasopharynx S. pneumoniae encounters glycoconjugates composed of a variety of monosaccharides, which can potentially be used as nutrients once depolymerized by glycosidases. Therefore, it is reasonable to hypothesise that the pneumococcus would rely on these glycan-derived sugars to grow. Here, we identified the sugar-specific catabolic pathways used by S. pneumoniae during growth on mucin. Transcriptome analysis of cells grown on mucin showed specific upregulation of genes likely to be involved in deglycosylation, transport and catabolism of galactose, mannose and N acetylglucosamine. In contrast to growth on mannose and N-acetylglucosamine, S. pneumoniae grown on galactose re-route their metabolic pathway from homolactic fermentation to a truly mixed acid fermentation regime. By measuring intracellular metabolites, enzymatic activities and mutant analysis, we provide an accurate map of the biochemical pathways for galactose, mannose and N-acetylglucosamine catabolism in S. pneumoniae. Intranasal mouse infection models of pneumococcal colonisation and disease showed that only mutants in galactose catabolic genes were attenuated. Our data pinpoint galactose as a key nutrient for growth in the respiratory tract and highlights the importance of central carbon metabolism for pneumococcal pathogenesis.

No MeSH data available.


Related in: MedlinePlus

Growth of S. pneumoniae D39 in glycan-derived sugars.Growth profiles of D39 grown in CDM supplemented with 30 mM of galactose (Gal), mannose (Man), N-acetylglucosamine (GlcNAc), glucosamine (GlcN), N-acetylgalactosamine (GalNAc), galactosamine (GalN) and glucose (Glc). Growth experiments were performed at 37ºC and at an initial of pH 6.5, using a 96-well microtiter plate reader. Symbols: (closed circle) Glc; (closed triangle) GlcNAc; (open diamond) GlcN; (open square) Gal; (closed diamond) Man, (dash) GalNAc and (open circle) GalN. Growth curves are plotted in decimal scale to assess for significant differences in the growth profiles.
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pone.0121042.g002: Growth of S. pneumoniae D39 in glycan-derived sugars.Growth profiles of D39 grown in CDM supplemented with 30 mM of galactose (Gal), mannose (Man), N-acetylglucosamine (GlcNAc), glucosamine (GlcN), N-acetylgalactosamine (GalNAc), galactosamine (GalN) and glucose (Glc). Growth experiments were performed at 37ºC and at an initial of pH 6.5, using a 96-well microtiter plate reader. Symbols: (closed circle) Glc; (closed triangle) GlcNAc; (open diamond) GlcN; (open square) Gal; (closed diamond) Man, (dash) GalNAc and (open circle) GalN. Growth curves are plotted in decimal scale to assess for significant differences in the growth profiles.

Mentions: The presence of the genes for a full metabolic pathway in the genome does not confirm that the pathway is functioning. Thus, we assessed the ability of monosaccharide constituents of host glycans to support growth of S. pneumoniae D39 in a chemically defined medium (Fig 2). Of the monosaccharides tested, growth was observed on glucosamine, GlcNAc, Gal and Man. In contrast, S. pneumoniae was unable to use GalNAc, galactosamine (Fig 2) and NeuNAc (data not shown) as single carbon sources for growth. Fucose was not tested, since inability to grow in this sugar has been previously documented [8,50–52]. The ability of each sugar to sustain growth was consistent with the conclusions from genome analysis.


Host glycan sugar-specific pathways in Streptococcus pneumoniae: galactose as a key sugar in colonisation and infection [corrected].

Paixão L, Oliveira J, Veríssimo A, Vinga S, Lourenço EC, Ventura MR, Kjos M, Veening JW, Fernandes VE, Andrew PW, Yesilkaya H, Neves AR - PLoS ONE (2015)

Growth of S. pneumoniae D39 in glycan-derived sugars.Growth profiles of D39 grown in CDM supplemented with 30 mM of galactose (Gal), mannose (Man), N-acetylglucosamine (GlcNAc), glucosamine (GlcN), N-acetylgalactosamine (GalNAc), galactosamine (GalN) and glucose (Glc). Growth experiments were performed at 37ºC and at an initial of pH 6.5, using a 96-well microtiter plate reader. Symbols: (closed circle) Glc; (closed triangle) GlcNAc; (open diamond) GlcN; (open square) Gal; (closed diamond) Man, (dash) GalNAc and (open circle) GalN. Growth curves are plotted in decimal scale to assess for significant differences in the growth profiles.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4380338&req=5

pone.0121042.g002: Growth of S. pneumoniae D39 in glycan-derived sugars.Growth profiles of D39 grown in CDM supplemented with 30 mM of galactose (Gal), mannose (Man), N-acetylglucosamine (GlcNAc), glucosamine (GlcN), N-acetylgalactosamine (GalNAc), galactosamine (GalN) and glucose (Glc). Growth experiments were performed at 37ºC and at an initial of pH 6.5, using a 96-well microtiter plate reader. Symbols: (closed circle) Glc; (closed triangle) GlcNAc; (open diamond) GlcN; (open square) Gal; (closed diamond) Man, (dash) GalNAc and (open circle) GalN. Growth curves are plotted in decimal scale to assess for significant differences in the growth profiles.
Mentions: The presence of the genes for a full metabolic pathway in the genome does not confirm that the pathway is functioning. Thus, we assessed the ability of monosaccharide constituents of host glycans to support growth of S. pneumoniae D39 in a chemically defined medium (Fig 2). Of the monosaccharides tested, growth was observed on glucosamine, GlcNAc, Gal and Man. In contrast, S. pneumoniae was unable to use GalNAc, galactosamine (Fig 2) and NeuNAc (data not shown) as single carbon sources for growth. Fucose was not tested, since inability to grow in this sugar has been previously documented [8,50–52]. The ability of each sugar to sustain growth was consistent with the conclusions from genome analysis.

Bottom Line: Therefore, it is reasonable to hypothesise that the pneumococcus would rely on these glycan-derived sugars to grow.Transcriptome analysis of cells grown on mucin showed specific upregulation of genes likely to be involved in deglycosylation, transport and catabolism of galactose, mannose and N acetylglucosamine.Our data pinpoint galactose as a key nutrient for growth in the respiratory tract and highlights the importance of central carbon metabolism for pneumococcal pathogenesis.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.

ABSTRACT
The human pathogen Streptococcus pneumoniae is a strictly fermentative organism that relies on glycolytic metabolism to obtain energy. In the human nasopharynx S. pneumoniae encounters glycoconjugates composed of a variety of monosaccharides, which can potentially be used as nutrients once depolymerized by glycosidases. Therefore, it is reasonable to hypothesise that the pneumococcus would rely on these glycan-derived sugars to grow. Here, we identified the sugar-specific catabolic pathways used by S. pneumoniae during growth on mucin. Transcriptome analysis of cells grown on mucin showed specific upregulation of genes likely to be involved in deglycosylation, transport and catabolism of galactose, mannose and N acetylglucosamine. In contrast to growth on mannose and N-acetylglucosamine, S. pneumoniae grown on galactose re-route their metabolic pathway from homolactic fermentation to a truly mixed acid fermentation regime. By measuring intracellular metabolites, enzymatic activities and mutant analysis, we provide an accurate map of the biochemical pathways for galactose, mannose and N-acetylglucosamine catabolism in S. pneumoniae. Intranasal mouse infection models of pneumococcal colonisation and disease showed that only mutants in galactose catabolic genes were attenuated. Our data pinpoint galactose as a key nutrient for growth in the respiratory tract and highlights the importance of central carbon metabolism for pneumococcal pathogenesis.

No MeSH data available.


Related in: MedlinePlus