Estudo do genoma funcional de Corynebacterium pseudotuberculosis através de diferentes estratégias proteômicas

• Ano de defesa: 2015
• Autor(a) principal: Wanderson Marques da Silva
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Genética
• Link de acesso: http://hdl.handle.net/1843/BUBD-A3KGNZ

Corynebacterium pseudotuberculosis is a facultative intracellular pathogenic species, subdivided into two biovars: C. pseudotuberculosis ovis, etiologic agent of caseous lymphadenitis in small ruminants, and C. pseudotuberculosis equi, which causes ulcerative lymphangitis in equines, mastitis in bovine, and oedematous skin disease in buffalos. In silico analysis of the genome of C. pseudotuberculosis revealed genes that can play an important role in both physiology and virulence of this pathogen. As a complement to structural genomics, functional genomics aims to elucidate the role that each gene plays in organism, as well as interaction of these genes into a biological network. Thus, in this PhD work, we used different proteomic approaches to evaluate the functional genome of C. pseudotuberculosis at the protein level to complement these previous in silico studies. First, the analysis of the exoproteome of strains 1002_ovis and C231_ovis, enable the characterization total of 60 proteins of C. pseudotuberculosis. In addition, 18 differentially regulated proteins were detected between the two strains. In a second study, the proteome of the strain 1002_ovis was evaluated in response to nitrosative stress, a stress encountered by the bacteria during the onset of the infection. A total of 845 proteins were analyzed, representing approximately 41% of the predicted proteome of this strain. A set of 58 proteins were found differentially regulated when compared to the control conditions. These 58 proteins are involved in different biological processes, and their induction may favor the survival of this pathogen under exposition to nitrosative stress. In a third study, the strains 1002_ovis and 258_equi, which represent the biovars ovis and equi of C. pseudotuberculosis, respectively, were used in a murine model of experimental infection. A comparative analysis of their extracellular proteomes before and after passage in the murine host revealed that 250 proteins were differentially regulated in C. pseudotuberculosis. These proteins are involved in transport pathways, virulence, cell adhesion and stress general response. Altogether, this PhD work allowed the generation of a protein data base, as well as the validation of several genes previously predicted in silico. In addition, this work reports the first comparative proteomic study of the biovars ovis and equi of C. pseudotuberculosis. The results generated in this study provide information about of factors that favor the physiology, virulence and pathogenesis of C. pseudotuberculosis.