Project description:We have previously shown that responses of the oral bacterium Streptococcus gordonii to arginine are co-ordinated by three paralogous regulators: ArcR, ArgR and AhrC. This set of experiments was designed to assess the effects of the ArcR gene regulator on global gene expression in Streptococcus gordonii under high arginine or following a shift to no arginine.
Project description:We have previously shown that responses of the oral bacterium Streptococcus gordonii to arginine are co-ordinated by three paralogous regulators: ArcR, ArgR and AhrC. This set of experiments was designed to assess the effects of the AhrC gene regulator on global gene expression in Streptococcus gordonii under high arginine or following a shift to no arginine.
Project description:We have previously shown that responses of the oral bacterium Streptococcus gordonii to arginine are co-ordinated by three paralogous regulators: ArgR, ArgR and AhrC. This set of experiments was designed to assess the effects of the ArgR gene regulator on global gene expression in Streptococcus gordonii under high arginine or following a shift to no arginine.
Project description:The microbiota has been reported to be correlated with carcinogenesis and cancer progression. However, its involvement in the pathology of mesothelioma remains unknown. In this study, we aimed to identify mesothelioma-specific microbiota using resected or biopsied mesothelioma samples. Eight mesothelioma tissue samples were analyzed via polymerase chain reaction (PCR) amplification and 16S rRNA gene sequencing. The operational taxonomic units (OTUs) of the effective tags were analyzed in order to determine the taxon composition of each sample. For the three patients who underwent extra pleural pneumonectomy, normal peripheral lung tissues adjacent to the tumor were also included, and the same analysis was performed. In total, 61 OTUs were identified in the tumor and lung tissues, which were classified into 36 species. Streptococcus australis and Ralstonia pickettii were identified as abundant species in almost all tumor and lung samples. Streptococcus australis and Ralstonia pickettii were found to comprise mesothelioma-specific microbiota involved in tumor progression; thus, they could serve as targets for the prevention of mesothelioma.
Project description:Oral streptococci metabolize carbohydrate to produce organic acids, which not only decrease the environmental pH, but also increase osmolality of dental plaque fluid due to tooth demineralization and consequent calcium and phosphate accumulation. Despite these unfavorable environmental changes, the bacteria continue to thrive. The aim of this study was to obtain a global view on strategies taken by Streptococcus mutans to deal with physiologically relevant elevated osmolality, and perseveres within a cariogenic dental plaque. We investigated phenotypic change of S. mutans biofilm upon hyperosmotic challenge. We found that the hyperosmotic condition was able to initiate S. mutans biofilm dispersal by reducing both microbial content and extracellular polysaccharides matrix. We then used whole-genome microarray with quantitative RT-PCR validation to systemically investigate the underlying molecular machineries of this bacterium in response to the hyperosmotic stimuli. Among those identified 40 deferentially regulated genes, down-regulation of gtfB and comC were believed to be responsible for the observed biofilm dispersal. Further analysis of microarray data showed significant up-regulation of genes and pathways involved in carbohydrate metabolism. Specific genes involved in heat shock response and acid tolerance were also upregulated, indicating potential cross-talk between hyperosmotic and other environmental stress. Hyperosmotic condition induces significant stress response on S. mutans at both phenotypic and transcriptomic levels. In the meantime, it may take full advantage of these environmental stimuli to better fit the fluctuating environments within oral cavity, and thus emerges as numeric-predominant bacterium under cariogenic conditions.