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GlmS and NagB regulate amino sugar metabolism in opposing directions and affect Streptococcus mutans virulence.

Kawada-Matsuo M, Mazda Y, Oogai Y, Kajiya M, Kawai T, Yamada S, Miyawaki S, Oho T, Komatsuzawa H - PLoS ONE (2012)

Bottom Line: NagB expression increased in the presence of GlcNAc while GlmS expression decreased, suggesting that the regulation of these enzymes, which functionally oppose one another, is dependent on the concentration of environmental GlcNAc.Also, nagB inactivation was found to decrease the expression of virulence factors, including cell-surface protein antigen and glucosyltransferase, and to decrease biofilm formation and saliva-induced S. mutans aggregation, while glmS inactivation had the opposite effects on virulence factor expression and bacterial aggregation.Our results suggest that GlmS and NagB function in sugar metabolism in opposing directions, increasing and decreasing S. mutans virulence, respectively.

View Article: PubMed Central - PubMed

Affiliation: Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.

ABSTRACT
Streptococcus mutans is a cariogenic pathogen that produces an extracellular polysaccharide (glucan) from dietary sugars, which allows it to establish a reproductive niche and secrete acids that degrade tooth enamel. While two enzymes (GlmS and NagB) are known to be key factors affecting the entrance of amino sugars into glycolysis and cell wall synthesis in several other bacteria, their roles in S. mutans remain unclear. Therefore, we investigated the roles of GlmS and NagB in S. mutans sugar metabolism and determined whether they have an effect on virulence. NagB expression increased in the presence of GlcNAc while GlmS expression decreased, suggesting that the regulation of these enzymes, which functionally oppose one another, is dependent on the concentration of environmental GlcNAc. A glmS-inactivated mutant could not grow in the absence of GlcNAc, while nagB-inactivated mutant growth was decreased in the presence of GlcNAc. Also, nagB inactivation was found to decrease the expression of virulence factors, including cell-surface protein antigen and glucosyltransferase, and to decrease biofilm formation and saliva-induced S. mutans aggregation, while glmS inactivation had the opposite effects on virulence factor expression and bacterial aggregation. Our results suggest that GlmS and NagB function in sugar metabolism in opposing directions, increasing and decreasing S. mutans virulence, respectively.

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Related in: MedlinePlus

glmS and nagB expression in ccpA mutant cells.After washing overnight cultures of WT and ccpA mutant cells, a small aliquot of each was inoculated into CDM-G50 with or without 50 mM GlcNAc and incubated at 37°C with 5% CO2. When the samples reached an OD660 of 0.5, cells were collected and prepared for quantitative PCR as described in the Materials and Methods. *p < 0.05, compared to WT UA159 as determined by a t-test.
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pone-0033382-g006: glmS and nagB expression in ccpA mutant cells.After washing overnight cultures of WT and ccpA mutant cells, a small aliquot of each was inoculated into CDM-G50 with or without 50 mM GlcNAc and incubated at 37°C with 5% CO2. When the samples reached an OD660 of 0.5, cells were collected and prepared for quantitative PCR as described in the Materials and Methods. *p < 0.05, compared to WT UA159 as determined by a t-test.

Mentions: Since CcpA plays a central role in carbon catabolite repression and affects the virulence of S. mutans[28], we investigated whether CcpA affects the expression of glmS and nagB. In ccpA mutant cells grown in CDM-G50 with or without 10 mM GlcNAc, glmS expression was unchanged compared with that in wild type (Fig. 6). The expression of nagB in the ccpA mutant grown in CDM-G50 was slightly decreased compared with that in wild type; however, its expression increased upon the addition of GlcNAc to a similar level as in wild type. gtfBC and spaP expression was unchanged in the ccpA mutant (data not shown).


GlmS and NagB regulate amino sugar metabolism in opposing directions and affect Streptococcus mutans virulence.

Kawada-Matsuo M, Mazda Y, Oogai Y, Kajiya M, Kawai T, Yamada S, Miyawaki S, Oho T, Komatsuzawa H - PLoS ONE (2012)

glmS and nagB expression in ccpA mutant cells.After washing overnight cultures of WT and ccpA mutant cells, a small aliquot of each was inoculated into CDM-G50 with or without 50 mM GlcNAc and incubated at 37°C with 5% CO2. When the samples reached an OD660 of 0.5, cells were collected and prepared for quantitative PCR as described in the Materials and Methods. *p < 0.05, compared to WT UA159 as determined by a t-test.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3306399&req=5

pone-0033382-g006: glmS and nagB expression in ccpA mutant cells.After washing overnight cultures of WT and ccpA mutant cells, a small aliquot of each was inoculated into CDM-G50 with or without 50 mM GlcNAc and incubated at 37°C with 5% CO2. When the samples reached an OD660 of 0.5, cells were collected and prepared for quantitative PCR as described in the Materials and Methods. *p < 0.05, compared to WT UA159 as determined by a t-test.
Mentions: Since CcpA plays a central role in carbon catabolite repression and affects the virulence of S. mutans[28], we investigated whether CcpA affects the expression of glmS and nagB. In ccpA mutant cells grown in CDM-G50 with or without 10 mM GlcNAc, glmS expression was unchanged compared with that in wild type (Fig. 6). The expression of nagB in the ccpA mutant grown in CDM-G50 was slightly decreased compared with that in wild type; however, its expression increased upon the addition of GlcNAc to a similar level as in wild type. gtfBC and spaP expression was unchanged in the ccpA mutant (data not shown).

Bottom Line: NagB expression increased in the presence of GlcNAc while GlmS expression decreased, suggesting that the regulation of these enzymes, which functionally oppose one another, is dependent on the concentration of environmental GlcNAc.Also, nagB inactivation was found to decrease the expression of virulence factors, including cell-surface protein antigen and glucosyltransferase, and to decrease biofilm formation and saliva-induced S. mutans aggregation, while glmS inactivation had the opposite effects on virulence factor expression and bacterial aggregation.Our results suggest that GlmS and NagB function in sugar metabolism in opposing directions, increasing and decreasing S. mutans virulence, respectively.

View Article: PubMed Central - PubMed

Affiliation: Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.

ABSTRACT
Streptococcus mutans is a cariogenic pathogen that produces an extracellular polysaccharide (glucan) from dietary sugars, which allows it to establish a reproductive niche and secrete acids that degrade tooth enamel. While two enzymes (GlmS and NagB) are known to be key factors affecting the entrance of amino sugars into glycolysis and cell wall synthesis in several other bacteria, their roles in S. mutans remain unclear. Therefore, we investigated the roles of GlmS and NagB in S. mutans sugar metabolism and determined whether they have an effect on virulence. NagB expression increased in the presence of GlcNAc while GlmS expression decreased, suggesting that the regulation of these enzymes, which functionally oppose one another, is dependent on the concentration of environmental GlcNAc. A glmS-inactivated mutant could not grow in the absence of GlcNAc, while nagB-inactivated mutant growth was decreased in the presence of GlcNAc. Also, nagB inactivation was found to decrease the expression of virulence factors, including cell-surface protein antigen and glucosyltransferase, and to decrease biofilm formation and saliva-induced S. mutans aggregation, while glmS inactivation had the opposite effects on virulence factor expression and bacterial aggregation. Our results suggest that GlmS and NagB function in sugar metabolism in opposing directions, increasing and decreasing S. mutans virulence, respectively.

Show MeSH
Related in: MedlinePlus