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Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

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Genomic comparison of virulent Rickettsia rickettsii Sheila Smith and avirulent Rickettsia rickettsii Iowa

ABSTRACT: Comparison of gene expression between the virulent Rickettsia rickettsii R strain and avirulent Rickettsia rickettsii Iowa. Keywords: virulent vs avirulent Virulent Rickettsia rickettsii R strain in triplicate was compared to avirulent Rickettsia rickettsii Iowa in triplicate

ORGANISM(S): Rickettsia rickettsii

SUBMITTER: Stephen Porcella

PROVIDER: E-GEOD-8041 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Genomic comparison of virulent Rickettsia rickettsii Sheila Smith and avirulent Rickettsia rickettsii Iowa.

Ellison Damon W DW Clark Tina R TR Sturdevant Daniel E DE Virtaneva Kimmo K Porcella Stephen F SF Hackstadt Ted T

Infection and immunity 20071119 2

Rickettsia rickettsii is an obligate intracellular pathogen that is the causative agent of Rocky Mountain spotted fever. To identify genes involved in the virulence of R. rickettsii, the genome of an avirulent strain, R. rickettsii Iowa, was sequenced and compared to the genome of the virulent strain R. rickettsii Sheila Smith. R. rickettsii Iowa is avirulent in a guinea pig model of infection and displays altered plaque morphology with decreased lysis of infected host cells. Comparison of the t ...[more]

PMID: 18025092

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Genomic comparison of virulent Rickettsia rickettsii Sheila Smith and avirulent Rickettsia rickettsii Iowa

Project description:Comparison of gene expression between the virulent Rickettsia rickettsii R strain and avirulent Rickettsia rickettsii Iowa. Keywords: virulent vs avirulent

2008-06-04 | GSE8041 | GEO

Rickettsia rickettsii

Project description:Genomic comparison of virulent Rickettsia rickettsii Sheila Smith and avirulent Rickettsia rickettsii Iowa

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Identification of an outer membrane protease of Rickettsia rickettsii responsible for maturation of surface exposed autotransporters

Project description:Members of the spotted fever group rickettsia express four large, surface-exposed autotransporters, at least one of which is a known virulence determinant. Autotransporter translocation to the bacterial outer surface, also known as type V secretion, involves formation of a b-barrel autotransporter domain in the periplasm that inserts into the outer membrane to form a pore through which the N-terminal passenger domain is passed and exposed on the outer surface. Two major surface antigens of Rickettsia rickettsii, are known to be exposed and the passenger domain cleaved from the autotransporter domain. A highly passaged strain of R. rickettsii, Iowa, fails to cleave these autotransporters and is avirulent. We have identified a putative peptidase, truncated in the Iowa strain, that when reconstituted into Iowa restores appropriate processing of the autotransporters as well as restoring a modest degree of virulence.

2023-07-06 | GSE226832 | GEO

Rickettsia rickettsii transcriptome - Blood feeding response

Project description:One of the most important vectors of the Brazilian Spotted Fever, the tick Amblyomma aureolatum in Brazil was used in this study. We laboratorial controlled the infection of adult females of A. aureolatum with the virulent brazilian strain Taiacu of Rickettsia rickettsii. The group of ticks was divided into 2 testing groups, group 2 (G2) composed of adult females incubated at 35°C for 3 days that were not fed after molting to adults and group 3 (G3) composed of adult females fed on its favorite natural host, the dog (Canis familiaris) also for 3 days. Right after incubation or feeding, ticks were individually dissected and all internal organs were transferred to RNAlater® Solution (Life Technologies) until gDNA and total RNA simultaneously isolation. A total of 14 ticks of each group were analyzed in two biological replicates (7 ticks each). Dye-swap was also applied to construct the technical replicate of each biological sample

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Rickettsia rickettsii transcriptome - Elevation of temperature response

Project description:One of the most important vectors of the Brazilian Spotted Fever, the tick Amblyomma aureolatum in Brazil was used in this study. We laboratorial controlled the infection of adult females of A. aureolatum with the virulent brazilian strain Taiacu of Rickettsia rickettsii. The group of ticks was divided into 2 testing groups, group 1 (G1) composed of adult females incubated at 25°C for 3 days and group 2 (G2) composed of adult females incubated at 35°C for 3 days. Right after incubation of both groups, ticks were individually dissected and all internal organs were transferred to RNAlater® Solution (Life Technologies) until gDNA and total RNA simultaneously isolation. A total of 14 ticks of each group were analyzed in two biological replicates (7 ticks each). Dye-swap was also applied to construct the technical replicate of each biological sample

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Multiomics study to identify virulence factors of Rickettsia prowazekii revealed its adaptive mutation capabilities

Project description:We identified four virulence phenotypes of Rickettsia prowazekii (the deadly agent of epidemic typhus) that are associated with the upregulation of antiapoptotic genes (virulent strain) or the Interferon I pathway (avirulent). Transcriptional and proteomic analyses of R. prowazekii linked surface protein expression and methylation with virulence. By sequencing a virulent strain and using comparative genomics, we found hotspots of mutations in homopolymeric tracts of poly(A) and poly(T) that lead to gene split and inactivation and explain the loss of virulence in the vaccine strain. These areas of instability explains adaptive mutations leading to virulence recovery in the vaccine strain. Transcriptional analysis of two different strains growing in L929 cells. A virulent strain (Rp22) was compared to a avirulent strain (Erus). The experiment was performed with 3 independant biological replicates.

2010-06-05 | E-GEOD-15630 | biostudies-arrayexpress

Limited transcriptional responses of Rickettsia rickettsii exposed to environmental stimuli

Project description:Rickettsiae are strict obligate intracellular pathogens that alternate between arthropod and mammalian hosts in a zoonotic cycle. Typically, pathogenic bacteria that cycle between environmental sources and mammalian hosts adapt to the respective environments by coordinately regulating gene expression such that genes essential for survival and virulence are expressed only upon infection of mammals. Temperature is a common environmental signal for upregulation of virulence gene expression although other factors may also play a role. We examined the transcriptional responses of Rickettsia rickettsii, the agent of Rocky Mountain spotted fever, to a variety of environmental signals expected to be encountered during its life cycle. R. rickettsii exposed to differences in growth temperature (25o C vs. 37o C), iron limitation, and host cell species displayed nominal changes in gene expression under any of these conditions with only 0, 5, or 7 genes, respectively, changing more than 3-fold in expression levels. R. rickettsii is not totally devoid of ability to respond to temperature shifts as cold shock (37o C vs. 4o C) induced a change greater than 3-fold in up to 57 genes. Rickettsiae continuously occupy a relatively stable environment which is the cytosol of eukaryotic cells. Because of their obligate intracellular character, rickettsiae are believed to be undergoing reductive evolution to a minimal genome. We propose that their relatively constant environmental niche has led to a minimal requirement for R. rickettsii to respond to environmental changes with a consequent deletion of non-essential transcriptional response regulators. A minimal number of transcriptional regulators in the R. rickettsii genome is consistent with this hypothesis. various growth and environmental condition comparisons

2010-06-25 | E-GEOD-14965 | biostudies-arrayexpress

Rickettsia rickettsii transcriptome - Blood feeding response

2013-12-01 | E-GEOD-44315 | biostudies-arrayexpress

Rickettsia rickettsii transcriptome - Elevation of temperature response

Project description:One of the most important vectors of the Brazilian Spotted Fever, the tick Amblyomma aureolatum in Brazil was used in this study. We laboratorial controlled the infection of adult females of A. aureolatum with the virulent brazilian strain Taiacu of Rickettsia rickettsii. The group of ticks was divided into 2 testing groups, group 1 (G1) composed of adult females incubated at 25°C for 3 days and group 2 (G2) composed of adult females incubated at 35°C for 3 days. Right after incubation of both groups, ticks were individually dissected and all internal organs were transferred to RNAlater® Solution (Life Technologies) until gDNA and total RNA simultaneously isolation. A total of 14 ticks of each group were analyzed in two biological replicates (7 ticks each). Dye-swap was also applied to construct the technical replicate of each biological sample total RNA from both experimental samples (G1 and G2) was used for hybridization to dual channel arrays. Two biological replicates were used for each experimental group.

2013-12-01 | E-GEOD-44316 | biostudies-arrayexpress