Project description:To address the question of how quorum sensing controls biofilm formation in Acidithiobacillus ferrooxidans ATCC23270, the transcriptome of this organism in conditions in which quorum sensing response is stimulated by a synthetic acyl homoserine lactone (AHL) analogue has been studied. Tetrazole 9c was used in DNA microarray experiments that allowed the identification of genes regulated by quorum sensing signalling, and more particularly those involved in early biofilm formation.
Project description:Quorum sensing is a cell to cell communication process that involves chemical signaling. Yersinia pestis, the agent of plague, has two functional AHL quorum sensing systems Ysp and Ype. For several reasons, it was not clear what effect AHL pathways have on virulence gene expression and survival in the two different hosts, flea and human. To investigate to what effect AHL quorum sensing has on gene expression, we conducted microarray studies comparing Yersinia pestis CO92 (∆pgm) to a double AHL mutant strain (∆pgm ΔypeIR) at 30°C.
Project description:Quorum sensing is a cell to cell communication process that involves chemical signaling. Yersinia pestis, the agent of plague, has two functional AHL quorum sensing systems Ysp and Ype. For several reasons, it was not clear what effect AHL pathways have on virulence gene expression and survival in the two different hosts, flea and human. To investigate to what effect Ysp AHL quorum sensing has on gene expression, we conducted microarray studies comparing Yersinia pestis CO92 (∆pgm) to a single AHL mutant strain (∆pgm ΔyspI) at 37°C.
Project description:Quorum sensing is a cell to cell communication process that involves chemical signaling. Yersinia pestis, the agent of plague, has two functional AHL quorum sensing systems Ysp and Ype. For several reasons, it was not clear what effect AHL pathways have on virulence gene expression and survival in the two different hosts, flea and human. To investigate to what effect Ysp AHL quorum sensing has on gene expression, we conducted microarray studies comparing Yersinia pestis CO92 (∆pgm) to a single AHL mutant strain (∆pgm ΔyspI) at 30°C.
Project description:Quorum sensing is a cell to cell communication process that involves chemical signaling. Yersinia pestis, the agent of plague, has two functional AHL quorum sensing systems Ysp and Ype. For several reasons, it was not clear what effect AHL pathways have on virulence gene expression and survival in the two different hosts, flea and human. To investigate to what effect AHL quorum sensing has on gene expression, we conducted microarray studies comparing Yersinia pestis CO92 (∆pgm) to a double AHL mutant strain (∆pgm ΔypeIR ΔyspIR) at 37°C.
Project description:Many bacteria harbor an incomplete quorum sensing system, wherein they possess LuxR homologues without the quorum sensing acyl-homoserine lactone (AHL) synthase, which is encoded by a luxI homolog. An artificial AHL-producing plasmid was constructed using a cviI gene encoding for C6-AHL (HHL) synthase from Chromobacterium violaceum and was introduced successfully into both wild-type and the ppoR (a luxR homolog) mutant. Our data provides evidence to suggest that the PpoR-HHL complex, but neither PpoR nor HHL alone, could attenuate growth, antibiotic resistance, and biofilm formation ability. In contrast, swimming motility, siderophore production, and indole degradation were enhanced by PpoR-HHL. The addition of exogenous indole increased biofilm formation and reduce swimming motility. Interestingly, indole proved ineffective in the presence of PpoR-HHL, thereby suggesting that the PpoR-HHL complex masks the effects of indole. Our data was supported by transcriptome analyses showing that the presence of the plasmid-encoded AHL synthase altered the expression of many genes on the chromosome in strain KT2440. Our results showed that heterologous luxI expression occurring via horizontal gene transfer can regulate a broad range of specific target genes, resulting in alterations of the phenotype and physiology of host cells.
Project description:Yersinia pestis, the etiological agent of plague, is able to sense cell density by quorum sensing. The function of quorum sensing in Y. pestis is not clear. Here, the process of AHL quorum sensing was investigated by comparing transcript profiles when two AHL quorum-sensing signals are added in. The strain Δpgm (pigmentation-negative) mutant was called wild type. The two AHLs signals are N-(3-Oxooctanoyl)-L-homoserine lactone and N-Hexanoyl-DL-homoserine lactone.The control consisted of cells grown and treated under the same conditions without added signals.
Project description:Yersinia pestis, the etiological agent of plague, is able to sense cell density by quorum sensing. The function of quorum sensing in Y. pestis is not clear. Here, the process of AHL quorum sensing was investigated by comparing transcript profiles when two AHL quorum-sensing signals are added in. The strain ∆pgm (pigmentation-negative) mutant R88 was called wild type. The two AHLs signals are N-(3-Oxooctanoyl)-L-homoserine lactone and N-Hexanoyl-DL-homoserine lactone.The control consisted of cells grown and treated under the same conditions without added signals.
Project description:Quorum sensing is a cell to cell communication process that involves chemical signaling. Yersinia pestis, the agent of plague, has two functional AHL quorum sensing systems Ysp and Ype. For several reasons, it was not clear what effect AHL pathways have on virulence gene expression and survival in the two different hosts, flea and human. To investigate to what effect AHL quorum sensing has on gene expression, we conducted microarray studies comparing Yersinia pestis CO92 (âpgm) to a double AHL mutant strain (âpgm ÎypeIR ÎyspIR) at 37°C. Six independent RNA samples from Y. pestis CO92 R114 AHL deficient cultures were paired with six independent RNA samples from control Y. pestis CO92 R88 cultures for hybridization to six two-color microarrays. For three arrays, the control RNA sample was labeled with Alexa 555 dye and the experimental RNA sample was labeled with Alexa 647 dye; the dyes were reversed for the other three arrays to account for any dye bias.
Project description:Quorum sensing is a cell to cell communication process that involves chemical signaling. Yersinia pestis, the agent of plague, has two functional AHL quorum sensing systems Ysp and Ype. For several reasons, it was not clear what effect AHL pathways have on virulence gene expression and survival in the two different hosts, flea and human. To investigate to what effect AHL quorum sensing has on gene expression, we conducted microarray studies comparing Yersinia pestis CO92 (â??pgm) to a double AHL mutant strain (â??pgm Î?ypeIR) at 30°C. Six independent RNA samples from Y. pestis CO92 Î?pgm Î?ypeIR cultures were paired with six independent RNA samples from control Y. pestis CO92 R88 cultures for hybridization to six two-color microarrays. For three arrays, the control RNA sample was labeled with Alexa 555 dye and the experimental RNA sample was labeled with Alexa 647 dye; the dyes were reversed for the other three arrays to account for any dye bias.