<i>Neorickettsia</i> spp.: Molecular Classification of a Vector and Roles of Bacterial Surface Proteins in Pathogenesis
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| Language: | English |
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The Ohio State University / OhioLINK
2011
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| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=osu1300901970 |
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English |
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Microbiology <i>Neorickettsia risticii</i> <i>Neorickettsia sennetsu</i> P51 surface proteins |
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Microbiology <i>Neorickettsia risticii</i> <i>Neorickettsia sennetsu</i> P51 surface proteins Gibson, Kathryn Elizabeth <i>Neorickettsia</i> spp.: Molecular Classification of a Vector and Roles of Bacterial Surface Proteins in Pathogenesis |
| author |
Gibson, Kathryn Elizabeth |
| author_facet |
Gibson, Kathryn Elizabeth |
| author_sort |
Gibson, Kathryn Elizabeth |
| title |
<i>Neorickettsia</i> spp.: Molecular Classification of a Vector and Roles of Bacterial Surface Proteins in Pathogenesis |
| title_short |
<i>Neorickettsia</i> spp.: Molecular Classification of a Vector and Roles of Bacterial Surface Proteins in Pathogenesis |
| title_full |
<i>Neorickettsia</i> spp.: Molecular Classification of a Vector and Roles of Bacterial Surface Proteins in Pathogenesis |
| title_fullStr |
<i>Neorickettsia</i> spp.: Molecular Classification of a Vector and Roles of Bacterial Surface Proteins in Pathogenesis |
| title_full_unstemmed |
<i>Neorickettsia</i> spp.: Molecular Classification of a Vector and Roles of Bacterial Surface Proteins in Pathogenesis |
| title_sort |
<i>neorickettsia</i> spp.: molecular classification of a vector and roles of bacterial surface proteins in pathogenesis |
| publisher |
The Ohio State University / OhioLINK |
| publishDate |
2011 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=osu1300901970 |
| work_keys_str_mv |
AT gibsonkathrynelizabeth ineorickettsiaisppmolecularclassificationofavectorandrolesofbacterialsurfaceproteinsinpathogenesis |
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1719429761799815168 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-osu13009019702021-08-03T06:01:58Z <i>Neorickettsia</i> spp.: Molecular Classification of a Vector and Roles of Bacterial Surface Proteins in Pathogenesis Gibson, Kathryn Elizabeth Microbiology <i>Neorickettsia risticii</i> <i>Neorickettsia sennetsu</i> P51 surface proteins <i>Neorickettsia</i> spp. are Gram-negative, obligate intracellular bacteria of the family Anaplasmataceae. Given their prevalence throughout the world, their propensity to cause human disease and deadly animal diseases, and the continuing discovery of new <i>Neorickettsia</i> spp., they are significant pathogens requiring better comprehension. The overall objective of this dissertation is to determine the host-bacterium relationships of <i>Neorickettsia</i>. Chapter 1 details background on Neorickettsia spp., with emphasis on <i>Neorickettsia risticii</i> and <i>Neorickettsia sennetsu</i>. The objective of Chapter 2 was to demonstrate the lineage of all <i>N. risticii</i>-infected trematode life stages. The study established the molecular identification of the <i>N. risticii</i> adult trematode host and its immature life stages, demonstrating as hypothesized that all life stages harboring <i>N. risticii</i> belong to the same clade. The objective of Chapter 3 was to determine the major surface proteins of <i>N. sennetsu</i> involved in host-pathogen interaction and to determine the roles of the major surface proteins. Four proteins: the 51-kDa antigen (P51), <i>Neorickettsia</i> surface proteins 2 (Nsp2) and 3 (Nsp3), and heat-shock protein 60 (GroEL), were found to have the highest surface expression. It was hypothesized that the two major β-barrel proteins, P51 and Nsp3 function as porins. The outer membrane fraction of <i>N. sennetsu</i>, as well as native P51 and Nsp3 were incorporated into proteoliposomes and tested by porin-swelling assays, and it was confirmed that P51 is a large porin. The objective of Chapter 4 was to determine levels of variation within predicted surface-exposed proteins of <i>N. risticii</i>, with the hypothesis being that geographic and temporal variation would occur among strains of <i>N. risticii</i>. Variation in P51 demonstrated geographic separation of <i>N. risticii</i> strains. Nsp2, Nsp3, and strain-specific antigen 3 (Ssa3) demonstrated temporal variation. Variety within the β-barrel proteins P51, Nsp2, and Nsp3 occurred mainly within regions predicted as external loops. Ssa3 variation mainly occurred in an N-terminal localized repeat region and consisted of changes in the number of 52-aa repeats. The objective of Chapter 5 was to determine causes of cytokine and chemokine induction in <i>N. sennetsu</i> infection, thus potential reasons for disease symptoms. The studies in this chapter first validated the mouse model of Sennetsu neorickettsiosis in immunocompetent BALB/c mice and then demonstrated cytokine and chemokine production by quantitative reverse-transcriptase polymerase chain reaction within spleens of infected mice during disease. Cytokine and chemokine production in the whole mouse was replicated <i>in vitro</i> within splenocyte and bone marrow-derived macrophage (BMDM) cultures, with significant induction of IL-1β, CXCL2, and IL-12A (p35) mRNAs occurring within whole bacteria and the Sarkosyl-purified bacterial outer membrane fraction of <i>N. sennetsu</i>. It was hypothesized that P51 is a major cause of cytokine induction, is recognized by Toll-like receptor 2, and that cytokine/chemokine induction is MyD88 dependent. Preliminary studies showed that cytokine/chemokine levels were reduced in MyD88-knockout mouse BMDMs and TLR2-knockout mouse splenocytes incubated with whole bacteria and in TLR2-knockout mouse BMDMs incubated with whole bacteria and bacterial outer membrane fraction. In conclusion, these studies demonstrated important host-pathogen relationships during Neorickettsial infection and disease useful for further understanding of these bacteria. 2011-03-31 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1300901970 http://rave.ohiolink.edu/etdc/view?acc_num=osu1300901970 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |