Project description:Yersinia pestis, the etiologic agent of plague, emerged as a flea-borne pathogen only within the last 6,000 years. Just five simple genetic changes in the Yersinia pseudotuberculosis progenitor, which served to eliminate toxicity to fleas and to enhance survival and biofilm formation in the flea digestive tract, were key to the transition to the arthropod-borne transmission route. To gain a deeper understanding of the genetic basis for the development of a transmissible biofilm infection in the flea foregut, we evaluated additional gene differences and performed in vivo transcriptional profiling of Y. pestis, Y. pseudotuberculosis wild-type (unable to form biofilm in the flea foregut), and a Y. pseudotuberculosis mutant strain (able to produce foregut-blocking biofilm in fleas) recovered from fleas 1 day and 14 days after an infectious bloodmeal. Surprisingly, the Y. pseudotuberculosis mutations that increased c-di-GMP levels and enabled biofilm development in the flea did not change expression levels of the hms genes responsible for the synthesis and export of the extracellular polysaccharide matrix required for mature biofilm formation. The Y. pseudotuberculosis mutant uniquely expressed much higher levels of one of the Yersinia Type VI secretion systems (T6SS-4) in the flea, and this locus was required for flea blockage by Y. pseudotuberculosis, but not by Y. pestis. Significant differences between the two species in expression of several metabolism genes, the Psa fimbrial genes, quorum sensing related genes, transcriptional regulators, and stress response genes were evident during flea infection. The results provide insights into how Y. pestis has adapted to life in its flea vector and point to evolutionary changes in the regulation of biofilm development pathways in these two closely related species
Project description:Whole transcriptome assessment of the Yersinia pseudotuberculosis strain YPIII. The Y. pseudotuberculosis rovA regulon was determined in Yersinia minimal minimum developed for the study. RovA is a key regulator for Yersinia virulence.
Project description:Whole transcriptome assessment of the Yersinia pseudotuberculosis strain YPIII. The Y. pseudotuberculosis csrA regulon was determined in Yersinia minimal minimum developed for the study. CsrA is a key regulator coordinating virulence and metabolism.
Project description:Whole transcriptome assessment of the Yersinia pseudotuberculosis strain YPIII. The Y. pseudotuberculosis crp regulon was determined in Yersinia minimal minimum developed for the study. Crp is a key regulator coordinating virulence and metabolism.
Project description:Yersinia pestis (Y. pestis) is the etiologic agent of the plague, an endemic zoonotic disease of critical clinical and historic importance. The species belongs to a genus comprising eleven members, three of which are human pathogens. Y. pestis and its closest extant relative, Yersinia pseudotuberculosis, are very similar in many respects, yet there is a distinct dichotomy between these species in terms of pathogenicity. Y. pseudotuberculosis produces a relatively benign food- or water-borne gastroenteritis with rare cases of potentially fatal bacteremia. In contrast, the characteristics of high infectivity and high mortality have made Y. pestis a pathogen of historic importance with devastating effects on the human populace over the course of three major pandemics. These qualities coupled with the emergence of multi-drug resistant variants make Y. pestis an ideal candidate for use as a bioterrorism agent. Consequentially, evolutionary biology of this organism has become a priority in the counter-terrorism research effort. The flow of genetic information within the Y. pseudotuberculosis/Y. pestis group motivated us to identify novel genes for the purpose of creating a pan-genome species DNA microarray to better understand the phylogenomic relationships among its members. Based on the sequence information be generated from the novel gene discovery project conducted at the PFGRC as well as other publicly available sources regarding Yersinia spp. genome sequences, we designed a species microarray which represents the hitherto known genetic repertoire of this taxonomic group. In order to create a species microarray that represents novel genes or genes with significant sequence variation, the ArrayOligoSelector software (http://arrayoligosel.sourceforge.net/) was used to design a 70-mer oligonucleotide for each of the annotated ORFs or partial ORFs. A detailed description of the 70-mer oligo design process and filters developed by the PFGRC can be found on the PFGRC web site at (http://pfgrc.tigr.org/presentations/seminars/oligo_design_final.pdf).
Project description:Enteropathogenic Yersinia enterocolitica and Yersinia pseudotuberculosis share many traits in terms of infections they cause, but their epidemiology and ecology seem to differ in many ways. Pigs are the only known reservoir for Y. enterocolitica 4/O:3 strains while Y. pseudotuberculosis strains have been isolated from variety of sources including fresh vegetables and wild animals. A comparative genomic hybridization (CGH) analysis with a DNA microarray based on three Yersinia enterocolitica and four Yersinia pseudotuberculosis genomes was conducted to shed light on genomic differences between the enteropathogenic Yersinia. In total 99 strains isolated from various sources were hybridized and analyzed.
Project description:Yersinia pestis (Y. pestis) is the etiologic agent of the plague, an endemic zoonotic disease of critical clinical and historic importance. The species belongs to a genus comprising eleven members, three of which are human pathogens. Y. pestis and its closest extant relative, Yersinia pseudotuberculosis, are very similar in many respects, yet there is a distinct dichotomy between these species in terms of pathogenicity. Y. pseudotuberculosis produces a relatively benign food- or water-borne gastroenteritis with rare cases of potentially fatal bacteremia. In contrast, the characteristics of high infectivity and high mortality have made Y. pestis a pathogen of historic importance with devastating effects on the human populace over the course of three major pandemics. These qualities coupled with the emergence of multi-drug resistant variants make Y. pestis an ideal candidate for use as a bioterrorism agent. Consequentially, evolutionary biology of this organism has become a priority in the counter-terrorism research effort. The flow of genetic information within the Y. pseudotuberculosis/Y. pestis group motivated us to identify novel genes for the purpose of creating a pan-genome species DNA microarray to better understand the phylogenomic relationships among its members. Based on the sequence information be generated from the novel gene discovery project conducted at the PFGRC as well as other publicly available sources regarding Yersinia spp. genome sequences, we designed a species microarray which represents the hitherto known genetic repertoire of this taxonomic group. In order to create a species microarray that represents novel genes or genes with significant sequence variation, the ArrayOligoSelector software (http://arrayoligosel.sourceforge.net/) was used to design a 70-mer oligonucleotide for each of the annotated ORFs or partial ORFs. A detailed description of the 70-mer oligo design process and filters developed by the PFGRC can be found on the PFGRC web site at (http://pfgrc.tigr.org/presentations/seminars/oligo_design_final.pdf). One hundred fifty six query strains were investigated in this study, with each query strain hybridized against the reference strain, CO92. Each strain has a single dye experiment. Each oligo is spotted on the Y. pestis species microarray once. Positive controls on the array consist of oligos designed from the sequenced reference genome, CO92, and negative controls on the array consist of oligos designed from the thale cress plant, Arabidopsis thaliana.The microarrays also had Agilent internal controls.
Project description:Yersinia pseudotuberculosis is a Gram-negative bacterium capable of causing gastrointestinal infection and is closely related to the highly virulent plague bacillus Yersinia pestis. Infection by both species are currently treatable with antibiotics such as ciprofloxacin, a quinolone-class drug of major clinical importance in the treatment of many other infections. Our current understanding of the mechanism of action of ciprofloxacin is that it inhibits DNA replication by targeting DNA gyrase, and that resistance is primarily due to mutation at this target site, along with generic efflux and detoxification strategies. We utilised transposon directed insertion site sequencing (TraDIS or TnSeq) to identify the non-essential chromosomal genes in Y. pseudotuberculosis that are required to tolerate sub-lethal concentrations of ciprofloxacin in vitro. As well as highlighting recognised antibiotic resistance genes, we provide evidence that a multitude of genes involved in regulating DNA replication and repair are central in enabling Y. pseudotuberculosis to tolerate the antibiotic, including dksA (yptb0734), a regulator of RNA polymerase and hda (yptb2792), an inhibitor of DNA replication initiation. We furthermore demonstrate that even at sub-lethal concentrations, ciprofloxacin causes severe cell-wall stress, requiring lipopolysaccharide lipid A, O-antigen and core biosynthesis genes to resist the sub-lethal effects of the antibiotic. It is evident that coping with the consequence(s) of antibiotic-induced stress requires the contribution of scores of genes that are not exclusively engaged in drug-resistance.