Rickettsiae prowazekii, the etiologic agent of epidemic thyphus, is an obligate intracellular parasitic bacterium that grows directly within the cytoplasm of its eucaryotic host cell, unbound by a vacuolar membrane. The overall goal of this research is to increase our understanding of the biochemical and genetic mechanisms involved in the successful intracellular parasitism by this organism. Previous work, employing recombinant DNA techniques, has led to the isolation of a number of R. prowazekii genes. A major goal of the work described in this application is the characterization of these genes and gene products using DNA sequence analysis and subsequent comparison studies with corresponding genes and gene products found in Escherichia coli and/or eucaryotic systems. Additional genes, coding for enzymes of the tricarboxylic acid cycle, will be isolated in order to investigate coordinate expression of rickettsial genes. The cloning of genes coding for proteins of the rickettsial cell surface will also be vigorously pursued. Isolation and characterization of these genes and gene products will form the foundation for subsequent studies on rickettsial recognition and penetration of its host cell. A major objective of this grant will be to use the knowledge gained from the isolation and characerization of rickettsial genes to probe the regulatory control mechanisms in viable rickettsiae. Cloned genes or appropriate fragments will be used as probes to detect specific messenger RNA. Finally, this work will begin to establish a system for the direct genetic analysis of R. prowazekii. This will involve screening low passaged R. prowazekii strain for naturally-occurring plasmids potentially useful as rickettsial vectors. In addition, studies designed to assess the ability of R. prowazekii to take-up and express exogenous DNA will also be performed. This work should provide an understanding of rickettsial gene structure and function and define the limits of direct genetic manipulation in this obligate intracellular parasite.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI020384-06
Application #
3130023
Study Section
Tropical Medicine and Parasitology Study Section (TMP)
Project Start
1983-07-01
Project End
1989-06-30
Budget Start
1988-07-01
Budget End
1989-06-30
Support Year
6
Fiscal Year
1988
Total Cost
Indirect Cost
Name
University of South Alabama
Department
Type
Schools of Medicine
DUNS #
City
Mobile
State
AL
Country
United States
Zip Code
36688
McClure, Erin E; Chávez, Adela S Oliva; Shaw, Dana K et al. (2017) Engineering of obligate intracellular bacteria: progress, challenges and paradigms. Nat Rev Microbiol 15:544-558
Driskell, Lonnie O; Tucker, Aimee M; Woodard, Andrew et al. (2016) Fluorescence Activated Cell Sorting of Rickettsia prowazekii-Infected Host Cells Based on Bacterial Burden and Early Detection of Fluorescent Rickettsial Transformants. PLoS One 11:e0152365
Wood, David O; Wood, Raphael R; Tucker, Aimee M (2014) Genetic systems for studying obligate intracellular pathogens: an update. Curr Opin Microbiol 17:11-6
Wood, David O; Hines, Andria; Tucker, Aimee M et al. (2012) Establishment of a replicating plasmid in Rickettsia prowazekii. PLoS One 7:e34715
Clark, Tina R; Lackey, Amanda M; Kleba, Betsy et al. (2011) Transformation frequency of a mariner-based transposon in Rickettsia rickettsii. J Bacteriol 193:4993-5
Woodard, Andrew; Wood, David O (2011) Analysis of convergent gene transcripts in the obligate intracellular bacterium Rickettsia prowazekii. PLoS One 6:e16537
Tucker, Aimee M; Driskell, Lonnie O; Pannell, Lewis K et al. (2011) Differential proteomic analysis of Rickettsia prowazekii propagated in diverse host backgrounds. Appl Environ Microbiol 77:4712-8
Driskell, Lonnie O; Yu, Xue-jie; Zhang, Lihong et al. (2009) Directed mutagenesis of the Rickettsia prowazekii pld gene encoding phospholipase D. Infect Immun 77:3244-8
Liu, Zhi-Mei; Tucker, Aimee M; Driskell, Lonnie O et al. (2007) Mariner-based transposon mutagenesis of Rickettsia prowazekii. Appl Environ Microbiol 73:6644-9
Tucker, Aimee M; Pannell, Lewis K; Wood, David O (2005) Dissecting the Rickettsia prowazekii genome: genetic and proteomic approaches. Ann N Y Acad Sci 1063:35-46

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