Camila Azevedo

Suche


B5 Analysis of virulence factors of Corynebacterium diphtheriae

Principal investigator
Andreas Burkovski

Mentor

PhD exam: 25.09.2015

Characterization of Corynebacterium diphtheriae virulence factors

Corynebacterium diphtheriae is a microorganism of global significance for being the etiologic agent of diphtheria and systemic infections. The diphtheria bacillus has been classically described as an extracellular pathogen. However, it was demonstrated that this microorganism is internalized by epithelial cells and presents number of virulence factors that may act independently of diphtheria toxin. Comparative proteomic analysis in silico and in vitro suggested the importance of the protein DIP0733 and indicated its ability to interact with matrix proteins and cell surfaces, participating in cellular internalization and induction of apoptosis. Therefore, we aimed to elucidate the role of the gene encoding the protein DIP0733 and how the process of interaction with the host cell contributes as a virulence property. We used the sequenced toxigenic CDC-E8392 strain of C. diphtheriae to obtain a insertion mutant in this gene. The mutant strain showed a kanamycin-resistant phenotype and insertion of the plasmid was confirmed by PCR and Southern blot assay.We are analysing the differences between the wild-type and mutant strains by determining the pattern of adhesion and invasion in HEp-2 and HeLa cells, as well as infection and colonization in Caenorhabtitis elegans. Interestingly, the colonization of mutant strain seems to be more attenuated than the wild type. Further investigations are being analysed about this effects in C. elegans.

Figure:Colonization of Caenorhabtitis elegans with wild type strain of C. diphtheriae CDC-E8392 and the respective mutant CDCE8392∆DIP0733. C: elegans L4 fed with (A) Eschericha coli OP50, (B) Corynebacterium diphtheriae CDC-E8392, (C) Corynebacterium diphtheriae CDC-E8392 DIP0733::pCR2.1-TOPO ‘DIP0733’. Tails of nematodes are indicated by arrows.

 

Publications

Antunes, C. A., Sanches Dos Santos, L., Hacker, E., Köhler, S., Bösl, K., Ott, L., de Luna, M., Hirata, R., Jr., Azevedo, V. A., Mattos-Guaraldi, A. L. & Burkovski, A. (2015). Characterization of DIP0733, a multi-functional virulence factor of Corynebacterium diphtheriae. Microbiology 161, 639-647.

 

Presentations

July 2015 7th Annual Retreat, Erlangen School of Molecular Communication, Schloss Hirschberg, Beilngries, Germany
Caenorhabditis elegans star formation and negative chemotaxis induced by infection with corynebacteria”
Poster
     
October 2014 66. Jahrestagung der Deutschen Gesellschaft für Hygiene und Mikrobiologie (DGHM) e.V., Dresden, Germany
"Characterization of a multi-functional virulence factor of Corynebacterium diphtheriae"
Poster
     
July 2014

6th Annual Retreat, Erlangen School of Molecular Communication, Kloster Banz, Bad Staffelstein, Germany
"Characterization of a multi-functional virulence factor of Corynebacterium diphtheriae"

Talk and Poster
     

Awards

Best Poster Award

third place

7th Annual Retreat, Erlangen School of Molecular Communication, Schloss Hirschberg, Beilngries, Germany, July 2015
"Caenorhabditis elegans star formation and negative chemotaxis induced by infection with corynebacteria"

Best Poster Award

second place

6th Annual Retreat, Erlangen School of Molecular Communication Kloster Banz, Bad Staffelstein, Germany, July 2014
"Characterization of a multi-functional virulence factor of Corynebacterium diphtheriae"