Project description:Pneumonic plague is the most deadly form of infection caused by Yersinia pestis and can progress extremely fast. However, our understanding on the host transcriptomic response to pneumonic plague is insufficient. Here, we used RNA-sequencing technology to analyze transcriptomic responses in mice infected with fully virulent strain 201 or EV76, a live attenuated vaccine strain lacking the pigmentation locus. Approximately 600 differentially expressed genes (DEGs) were detected in lungs from both 201- and EV76-infected mice at 12 hours post-infection (hpi). DEGs in lungs of 201-infected mice exceeded 2,000 at 48 hpi, accompanied by sustained large numbers of DEGs in the liver and spleen; however, limited DEGs were detected in those organs of EV-infected mice. Remarkably, DEGs in lungs were significantly enriched in critical immune responses pathways in EV76-infected but not 201-infected mice, including antigen processing and presentation, T cell receptor signaling among others. Pathological and bacterial load analyses confirmed the rapid systemic dissemination of 201-infection and the confined EV76-infection in lungs. Our results demonstrate that fully virulent Y. pestis strongly inhibits both the innate and adaptive immune responses that are substantially stimulated in a self-limited infection, which update our holistic views on the transcriptomic response to pneumonic plague.
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 quorum sensing was investigated by comparing transcript profiles when three quorum-sensing synthase genes are knocked out. Two strains, ∆pgm (pigmentation-negative) mutant R88 as treatment and quorum sensing null strain R115 with mutations (∆pgm, ∆ypeIR, ∆yspIR, and ∆luxS) as control, are used in this analysis.
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 autoinducer 2 (AI-2) quorum sensing was investigated by comparing transcript profiles when luxS gene was knocked out. The luxS gene encodes S-ribosylhomocysteinase which can produce DPD, a precursor of AI-2. The strain ∆pgm (pigmentation-negative) mutant R88 was called wild type. The ∆pgm ∆luxS mutant was called control.
Project description:Yersinia pestis is the etiology of plague that is able to sense cell density by quorum sensing. The function of quorum sensing in Y.pestis is not clear. Here, the process of quorum sensing was investigated by comparing transcript profiles when three quorum sensing synthase genes are knocked out. Two strains, ∆pgm (pigmentation-negative) mutant R88 as treatment and 3XQS mutant with mutation (∆pgm, ∆ypeIR, ∆yspIR, and ∆luxS) R115 as control are used in this analysis.
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 autoinducer-2 (AI-2) quorum sensing was investigated by comparing transcript profiles when AI-2 quorum-sensing signal is added in. The strain ∆pgm(pigmentation-negative) mutant R88 was used as wild type. The control consisted of cells grown and treated under the same conditions without added signals.
Project description:Yersinia pestis is a gram-negative bacterium that causes plague, a disease linked historically to the Black Death in Europe during the Middle Ages and to several outbreaks during the modern era. Metabolism in Y. pestis displays remarkable flexibility and robustness, allowing the bacterium to proliferate in both warm-blooded mammalian hosts and cold-blooded insect vectors such as fleas.Here we report a genome-scale reconstruction and mathematical model of metabolism for Y. pestis CO92 and supporting experimental growth and metabolite measurements. The model contains 815 genes, 678 proteins, 963 unique metabolites and 1678 reactions, accurately simulates growth on a range of carbon sources both qualitatively and quantitatively, and identifies gaps in several key biosynthetic pathways and suggests how those gaps might be filled. Furthermore, our model presents hypotheses to explain certain known nutritional requirements characteristic of this strain.Y. pestis continues to be a dangerous threat to human health during modern times. The Y. pestis genome-scale metabolic reconstruction presented here, which has been benchmarked against experimental data and correctly reproduces known phenotypes, provides an in silico platform with which to investigate the metabolism of this important human pathogen.
