Project description:Purpose: The goal of this study is to complare the transcitpional profiles of freshly isolated, murine splenic and hepatic memory B cells (B220+ CD73+) sorted as CD11b, CD11c double negative and CD11b, CD11c double positive cell populations induced by Ehrlichia muris infection.
Project description:We have previously described a novel taxon of the genus Ehrlichia (type strain WisconsinT), closely related to Ehrlichia muris, that causes human ehrlichiosis among patients with exposures to ticks in the upper midwestern USA. DNA from this bacterium was also detected in Ixodes scapularis and Peromyscus leucopus collected in Minnesota and Wisconsin. To determine the relationship between the E. muris-like agent (EMLA) and other species of the genus Ehrlichia phenotypic, genotypic and epidemiologic comparisons were undertaken, including sequence analysis of eight gene loci (3906 nucleotides) for 39 EMLA DNA samples and the type strain of E. muris AS145T. Three loci were also sequenced from DNA of nine strains of E. muris from mouse spleens from Japan. All sequences from E. muris were distinct from homologous EMLA sequences, but differences between them were less than those observed among other species of the genus Ehrlichia. Phenotypic comparison of EMLA and E. muris revealed similar culture and electron microscopic characteristics, but important differences were noted in their geographic distribution, ecological associations and behavior in mouse models of infection. Based on these comparisons, we propose that type strain WisconsinT represents a novel subspecies, Ehrlichia murissubsp. eauclairensis,subsp. nov. This strain is available through the Centers for Disease Control and Prevention Rickettsial Isolate Reference Collection (CRIRC EMU002T) and through the Collection de Souches de l'Unité des Rickettsies (CSURP2883 T). The subspecies Ehrlichia murissubsp. muris subsp. nov. is automatically created and the type strain AS145T is also available through the same collections (CRIRC EMU001T, CSUR E2T). Included is an emended description of E. muris.
Project description:We performed bulk RNA sequencing on murine CXCR3+ and CXCR3-negative live singlet IgM+ IgD-neg CD19+ CD138-neg (B1 B cell-like) peritoneal cavity B cells to compare the transcriptomes of the two populations following i.p. infection with the intracellular bacterium Ehrlichia muris. Total RNA was extracted and sequenced, followed by pseudoalignment, quality assessment, normalization, and analysis of differential gene expression. The CXCR3+ B1 B cell-like population was highly enriched for genes involved in proliferation, metabolism, and cell division, whereas the CXCR3- B1 B cell-like population transcriptionally resembled canonical B1 B cells and did not appear to be proliferative. These results suggest local proliferation of CXCR3+ B cells occurs in the peritoneal cavity during acute infection with an intracellular bacterium.
Project description:We report here the complete genome sequence of Ehrlichia muris strain AS145(T), which was isolated from a wild mouse in 1983 in Japan. E. muris establishes persistent infections in laboratory mice and is widely used as a surrogate pathogen in a murine model of ehrlichiosis.
Project description:Human ehrlichiosis is due to infection by tick transmitted bacteria of the genus Ehrlichia. Based on a hypothesis for the biogeography of deer tick transmitted infections, we undertook a focused search for the Eurasian E. muris in North American deer ticks. The search was stimulated by anecdotal reports of E. muris-like infection in human ehrlichiosis patients from Wisconsin. We analyzed archived adult deer ticks collected in northern Wisconsin during the 1990s by specific polymerase chain reaction for evidence of infection, and sequenced amplification products to identify E. muris. About 1% of 760 adult deer ticks collected from Spooner, Wisconsin in the 1990s contained E. muris DNA. We conclude that E. muris was present in North American deer ticks a decade ago and is likely to infect this human biting vector elsewhere in the U.S. Biogeographic theory and molecular phylogenetic methods can facilitate a targeted search for potential zoonoses.
Project description:In order to study the transcriptome of the pathogen, Ehrlichia ruminantium, specific microoarray was designed and validated using genomic DNA of Gardel and Welgevonden strains. Gardel strain was isolated in Guadeloupe and Welgevonden strain in South Africa. DNA from Ehrlichia ruminantium was extracted from cell culture infected with Gardel passage 40 and Welgevonden passage 11, using QIAmp kit (Qiagen). Ehrlichia ruminantium DNA was labeled using BioPrime array CGH labeling system kit (Invitrogen) and Cy3-dCTP (Amersham). Arrays were incubated at 60°C for 20 hours in hybridization chamber. After hybridization, arrays were washed according to the Agilent protocol. Arrays were scanned and the signal intensity of all spots were quantified by Genepix pro 6.0 (Molecular Device Corporation) and data were saved for further analysis.
Project description:Infection of humans with Ehrlichia chaffeensis, the etiologic agent of human monocytic ehrlichiosis, can cause hepatitis of varying severity. When the three human isolates of E. chaffeensis, each belongs to different geno-groups, are inoculated into severe combined immunodeficiency mice, the severity of clinical signs and bacterial burden detected in the liver are strain Wakulla>Liberty>Arkansas. Disseminated and granulomatous inflammation is evident in the liver of mice infected with strains Wakulla and Arkansas, respectively, but not in mice infected with strain Liberty. In this paper, we used microarray analysis to define transcriptional profiles characteristic to the histopathological features in the mouse liver. Cytokine and chemokine profiles were strikingly different among three strains of E. chaffeensis: IFN-γ, CCL5, CXCL1, CXCL2, CXCL7 and CXCL9 were highly up-regulated with strain Arkansas, TNF-α, CCL2, CCL3, CCL5, CCL6, CCL12, CCL20, CXCL2, CXCL7, CXCL9 and CXCL13 were highly up-regulated with strain Wakulla. With strain Liberty, only CXCL13 was highly up-regulated. In the livers infected with the Arkansas strain, monocytes/macrophages and NK cells were enriched in the granulomas and increase of NK cell-marker mRNAs was detected. Livers infected with the Wakulla strain displayed infiltration of significantly more neutrophils and increase of neutrophil-marker mRNAs. Genes up-regulated commonly in the liver infected with the three stains are other host innate immune and inflammatory response genes including several acute phase proteins. Genes down-regulated commonly are related to host physiologic functions. The results suggest that marked modulation of host cytokine and chemokine profiles by E. chaffeensis strains underlie the distinct host liver disease.