Project description:The transport of carbohydrates by Streptococcus mutans is accomplished by the phosphoenolpyruvate-phosphotrasferase system (PTS) and ATP-binding cassette (ABC) transporters. To undertake a global transcriptional analysis of all S. mutans sugar transporters simultaneously, we used a whole-genome expression microarray. Global transcription profiles of S. mutans UA159 were determined for several carbohydrates. The results revealed that PTSs were responsible for transport of monosaccharides, disaccharides and sugar alcohols. Six PTSs were transcribed only if a specific sugar was present in the growth medium, thus they were regulated at the transcriptional level. These included transporters for fructose, lactose, cellobiose, trehalose, and two transporters for mannitol. Three PTSs were repressed under all conditions tested. Interestingly, five PTSs were always highly expressed regardless of the sugar source used, presumably suggesting their availability for immediate uptake of most common dietary sugars (glucose, fructose, maltose and sucrose). The ABC transporters were found to be specific for polysaccharides, raffinose, stachyose and isomaltosaccharides. Compared to the PTS, the ABC transporters showed higher transcription under several tested conditions, suggesting that they might be transporting multiple substrates. Keywords: carbohydrate response
Project description:Transcriptional analysis of the effects of sugar source in S. mutans RNA was extracted from 4 replicate samples of S. mutans UA159, UA159 grown in glucose or maltose in continuous culture to steady-state pH values of 7 or 5. RNA was labeled with Cy3. For each replicate, labeled RNA was hybridized to slides along with Cy5-labeled reference RNA, extracted from S. mutans UA159 cultures grown to mid-log.
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:Transcriptional Profiling of Streptococcus mutans UA159 Grown in Continuous Culture using TV Media Supplemented With 10 mM vs 100 mM Glucose. The genetic and phenotypic responses of Streptococcus mutans, an organism known to be strongly associated with the development of dental caries, to changes in carbohydrate availability were investigated. S. mutans UA159 or a derivative of UA159 lacking ManL, which is the EIIAB component (EIIABMan) of a mannose/glucose permease of the phosphoenolpyruvate:sugar phosphotransferase system (PTS) and a dominant effector of catabolite repression, were grown in continuous culture to steady-state in conditions of excess (100 mM) or limiting (10 mM) glucose. Microarrays using RNA from S. mutans UA159 revealed that 174 genes were differentially expressed in response to changes in carbohydrate availability (P < 0.001). Glucose-limited cells possessed higher PTS activity, could acidify the environment more rapidly and to a greater extent, and produced more ManL protein than cultures grown with excess glucose. Loss of ManL adversely affected carbohydrate transport and acid tolerance. Comp arison of the HPr protein in S. mutans UA159 and the manL deletion strain indicated that the differences in behaviors of the strains were not due to major differences in HPr pools or HPr phosphorylation status. Therefore, carbohydrate availability alone can dramatically influence the expression of physiologic and biochemical pathways that contribute directly to the virulence of S. mutans, and ManL has a profound influence on this behavior. Two-condition experiment, growth in 10 mM vs 100 mM glucose. Biological replicates: 3 per condition, independently grown and harvested. One replicate per array
