Dynamics of Streptococcus mutans transcriptome in response to starch and sucrose during biofilm development.
The combination of sucrose and starch in the presence of surface-adsorbed salivary α-amylase and bacterial glucosyltransferases increase the formation of a structurally and metabolically distinctive biofilm by Streptococcus mutans. This host-pathogen-diet interaction may modulate the formation of pathogenic biofilms related to dental caries disease. We conducted a comprehensive study to further investigate the influence of the dietary carbohydrates on S. mutans-transcriptome at distinct stages of biofilm development using whole genomic profiling with a new computational tool (MDV) for data mining. S. mutans UA159 biofilms were formed on amylase-active saliva coated hydroxyapatite discs in the presence of various concentrations of sucrose alone (ranging from 0.25 to 5% w/v) or in combination with starch (0.5 to 1% w/v). Overall, the presence of sucrose and starch (suc+st) influenced the dynamics of S. mutans transcriptome (vs. sucrose alone), which may be associated with gradual digestion of starch by surface-adsorbed amylase. At 21 h of biofilm formation, most of the differentially expressed genes were related to sugar metabolism, such as upregulation of genes involved in maltose/maltotriose uptake and glycogen synthesis. In addition, the groEL/groES chaperones were induced in the suc+st-biofilm, indicating that presence of starch hydrolysates may cause environmental stress. In contrast, at 30 h of biofilm development, multiple genes associated with sugar uptake/transport (e.g. maltose), two-component systems, fermentation/glycolysis and iron transport were differentially expressed in suc+st-biofilms (vs. sucrose-biofilms). Interestingly, lytT (bacteria autolysis) was upregulated, which was correlated with presence of extracellular DNA in the matrix of suc+st-biofilms. Specific genes related to carbohydrate uptake and glycogen metabolism were detected in suc+st-biofilms in more than one time point, indicating an association between presence of starch hydrolysates and intracellular polysaccharide storage. Our data show complex remodeling of S. mutans-transcriptome in response to changing environmental conditions in situ, which could modulate the dynamics of biofilm development and pathogenicity.
Klein
Marlise I
MI
Center for Oral Biology and Eastman Department of Dentistry, University of Rochester Medical Center, Rochester, New York, United States of America.
DeBaz
Lena
L
Agidi
Senyo
S
Lee
Herbert
H
Xie
Gary
G
Lin
Amy H-M
AH
Hamaker
Bruce R
BR
Lemos
José A
JA
Koo
Hyun
H
D001483:Base Sequence; D018441:Biofilms; D017931:DNA Primers; D020869:Gene Expression Profiling; D005798:Genes, Bacterial; D020411:Oligonucleotide Array Sequence Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013213:Starch / Q000494:pharmacology*; D013295:Streptococcus mutans / Q000187:drug effects* / Q000235:genetics; D013395:Sucrose / Q000494:pharmacology*
D017931:DNA Primers; D013395:Sucrose; D013213:Starch