Project description:H2O2 is an oxidative stress agent known to trigger an upregulation in expression of detoxification genes in Streptococcus mutans. Following discovery of a spontaneously-occurring perR mutation, we wanted to compare the transcriptomic responses of H2O2 exposure in S. mutans strains bearing an intact perR or a perR deletion.
Project description:Transcriptional profiles of a chlorhexidine tolerant Salmonella Typhimurium were compared to its, chlorhexidine sensitive, isogenic progenitor isolate. RNA was extracted from mid-log phase cells from both isolates, without chlorhexidine exposure and following exposure to 1 µg/ ml of chlorhexidine for 30 minutes. Transcriptional profiles of the tolerant isolate were compared to the sensitive isolate, with and without chlorhexidine exposure.
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 profiles of a chlorhexidine tolerant Salmonella Typhimurium were compared to its, chlorhexidine sensitive, isogenic progenitor isolate. RNA was extracted from mid-log phase cells from both isolates, without chlorhexidine exposure and following exposure to 1 µg/ ml of chlorhexidine for 30 minutes. Transcriptional profiles of the tolerant isolate were compared to the sensitive isolate, with and without chlorhexidine exposure. Carried out using 3 biological replicates for each sample; each sample hybridised in a two-channel hybridization against Salmonella genomic DNA as the comparator/reference
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: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:Despite the widespread use of antiseptics such as chlorhexidine digluconate (CHX) in dental practice and oral care, the risks of potential resistance toward antiseptics in oral bacteria have only been highlighted very recently. Since the molecular mechanisms behind antiseptic resistance or adaptation are not entirely clear yet and the bacterial stress response has not been investigated systematically so far, the aim of the present study was to investigate the transcriptomic stress response in Streptococcus mutans after treatment with CHX using RNA sequencing. Planktonic cultures of stationary phase S. mutans were treated with a sublethal dose of CHX (125 µg/mL) for 5 min. After treatment, RNA was extracted, and RNA sequencing was performed on the Illumina NextSeq 500. Differential expressed genes were analyzed and validated by qRT-PCR. The analysis of the differential gene expression following pathway analysis revealed a considerable number of genes and pathways significantly regulated in S. mutans after sublethal treatment with CHX. In summary, expression of 423 genes was up-regulated and 295 genes down-regulated after CHX treatment. Analysis of differentially expressed genes and significantly regulated pathways showed regulation of genes involved in purine nucleotide synthesis, biofilm formation, transport systems and stress responses. In conclusion, these results show an overview of the transcriptomic stress response in S. mutans upon exposure to CHX and give an insight in potential mechanisms that may result in development of resistances.
Project description:Characterization of preclinical models of intrahepatic cholangiocarcinoma progression that reliably recapitulate altered molecular features of the human disease. Here, we performed comprehensive gene expression profiling of cholangiocarcinoma tumors arising from bile duct inoculation of different grade malignant rat cholangiocytes. Tumors arising from bile duct inoculation of spontaneously-transformed low grade malignant rat BDE1 cholangiocytes (BDEsp cells) compared to tumors arising from the inoculation of high grade malignant erbB-2/neu- transformed BDE1 cholangiocytes (BDEneu cells) into the livers of syngeneic rats.
Project description:Our group recently transcriptomically characterized coculture growth between Streptococcus mutans and several species of commensal streptococci (Rose et al, 2023; Choi et al 2024). One interaction that stood out was with Streptococcus mitis ATCC 49456, which completely inhibited the growth of S. mutans during biofilm formation. This is due to abudant hydrogen peroxide production by S. mitis ATCC 49456, 3-5x higher than other oral commensal streptococci we have worked with. To understand how the transcriptome of S. mutans is modified in coculture with a high hydrogen peroxide producer, we evaluated the transcriptome during monoculture or coculture growth between the two strains. Our results show differential gene expression (DEGs) in S. mutans that follows other trends we have documented previously with other commensal Streptococcus species, as well as DEGs specific to the interaction with S. mitis.
