Project description:Our group recently transcriptomically characterized coculture growth between Streptococcus mutans and several species of commensal streptococci (Rose et al, 2023). However, these experiments were carried out in our lab-based experimental medium, tryptone and yeast extract (TY-). To understand whether culturing these species within a medium that more closely mimics their natural environment alters the interaction, we evaluated both monoculture and coculture growth between the dental caries pathogen Streptococcus mutans and oral commensal species Streptococcus oralis in a half TY- / half human saliva mix that was optimally chosen based on our initial characterization of oral streptococci behaviors in medium mixes containing saliva. Our results surprising show that inclusion of saliva enhances the competition of Streptococcus mutans against commensal streptococci through upregulation of carbohydrate uptake and glycolytic pathways.
Project description:Transcriptional profiling of early logarithmic phase culture (O.D=0.2-0.3) of Streptococcus mutans UA159 comparing control of untreated Streptococcus mutans UA159 bacteria with Streptococcus mutans UA159 bacteria spplemented with 20µM synthetic DPD (pre-AI-2) which regulates gene expression via AI-2 quorum sensing system.Three compairisons were performed at pHs of 7,6 and 5.
Project description:Childhood caries is an extremely common childhood chronic disease, affecting 60–90% of children in industrialized countries. It results in lesions in both the primary and permanent dentitions, hospitalizations and emergency room visits, high treatment costs, loss of school days, diminished ability to learn increases the risk of caries in adulthood. Streptococcus mutans is a key bacteria in caries development. While multiple caries risk factors have been identified, significant interpersonal variability not explained by known risk factors still exists. The immune system generates a personal antibody repertoire that helps maintain a balanced and healthy oral microbiome. Using mass-spectrometry, we probed in an hypothesis-free manner which S. mutans proteins are identified by antibodies of children with low and high DMFT (decayed, missing, filled teeth) scores. We identified a core set of proteins, recognized by the immune system of most individuals. This set was enriched with proteins enabling bacterial adhesion, and included glucosyltransferases and glucan-binding proteins known to be important for S. mutans cariogenicity. To explore the physiological relevance of these findings, we tested the ability of saliva from caries free individuals in preventing S. mutans from binding to the tooth surface. Indeed, saliva from individuals with caries free prevented S. mutans binding to teeth. These findings map the S. mutans proteome targeted by the immune system and suggest that inhibiting tooth attachment is a primary mechanism used by the immune system to maintain oral balance and prevent caries. These findings provide new insights into the role of the immune system in maintaining oral health and preventing caries development.
Project description:The influence of cranberry proanthocyanidins on the transcriptomic responses of Streptococcus mutans during biofilm formation was investigated. Treatment regimens simulating topical exposures experienced clinically (twice-daily, 60 s each) were used over saliva-coated hydroxyapatite biofilm model. Cranberry proanthocyanidins (1.5 mg/ml) in 15% ethanol was used to treat the biofilms. Four biological replicates each for the treatment and vehicle control were used for RNA extraction and microarray.
Project description:RNA-Seq was used to compare the transcriptome of Streptococcus mutans UA159 during growth alone in monoculture, in coculture with Streptococcus gordonii DL1, Streptococcus sanguinis SK36 or Streptococcus oralis 34, and in a quadculture containing all four species. Individual cultures of commensal species Streptococcus gordonii DL1, Streptococcus sanguinis SK36 and Streptococcus oralis 34 were sequenced as well. This revealed a common transcriptome pattern in S. mutans when grown in mixed-species culture, indepenedent of the species identity that S. mutans was cultured with. Additionally, transcriptome changes in the commensal species could also be determined when undergoing competition from S. mutans. RNA-Seq was used to compare the transcriptome of Streptococcus mutans UA159 during growth alone in monoculture or in coculture with Streptococcus sobrinus NIDR 6715, Lactobacillus casei ATCC 4646 or Corynebacterium matruchotii ATCC 14266. These data were compared to previous coculture and quadculture RNA-Seq data with commensal streptococci (GSE209925). These data confirmed a common transcriptome pattern in S. mutans when grown in mixed-species culture with commensal streptococci that is not present with non-commensal streptococci, indepenedent of the species identity that S. mutans was cultured with.
Project description:The influence of cranberry proanthocyanidins on the transcriptomic responses of Streptococcus mutans during biofilm formation was investigated.
Project description:Transcriptional profiling to investigate the response of Streptococcus mutans biofilms to starch and sucrose at distinct stages of biofilm development.
Project description:In the human pathogen Streptococcus mutans, the canonical peptide-based quorum sensing system is an inducible DNA repair system that is pivotal for bacterial survival. Previous work showed that the CSP signaling peptide is a stress-signaling alarmone that controls different stress-induced phenotypes. In this study, we exposed S. mutans to the CSP pheromone to mimic DNA damage conditions. Transcriptome analysis was then performed to evaluate the differential gene expression between the normal stationary phase cells and the CSP-induced stationary phase cells. The data obtained contribute to the understanding of the CSP-induced phenotypes in S. mutans.
Project description:Amino sugars, particularly glucosamine (GlcN) and N-acetylglucosamine (GlcNAc) are abundant carbon and nitrogen sources that are continually supplied in host secretions and the diet to biofilms colonizing the human mouth. Evidence is emerging that these amino sugars may provide an ecological advantage to beneficial commensals over oral pathobionts. Here we performed transcriptome analysis on Streptococcus mutans and Streptococcus gordonii growing in single-species or dual-species cultures with glucose, GlcN or GlcNAc as the primary carbohydrate source. Compared to glucose, GlcN caused drastic transcriptomic shifts in each bacterium when they were cultured alone. Likewise, co-cultivation in the presence of GlcN yielded transcriptomic profiles that were dramatically different than the single-species results from GlcN-grown cells. In contrast, GlcNAc elicited only minor changes in the transcriptome of either organism, in both single- and dual-species cultures. Interestingly, genes involved in pyruvate metabolism were among the most significantly affected by GlcN in both species, and these changes were consistent with measurements of pyruvate in culture supernates. Differing a previous report, growth of S. mutans alone with GlcN inhibited expression of multiple operons required for mutacin production. Co-cultivation with S. gordonii consistently increased the expression by S. mutans of two manganese transporter operons (slo and mntH) and decreased expression of mutacin genes. Conversely, S. gordonii appeared to be less affected by the presence of S. mutans, but did show increases in genes for biosynthetic processes in the co-cultures. In conclusion, amino sugars profoundly altered the interactions between the pathogen and the commensal, likely by reprogramming their central metabolism.