Induction of DnaK and GroEL in Brucella Ovis under Various Stress Conditions

Abstract

Brucella ovis is a facultative intracellular pathogen, able to survive and replicate within macrophages. The role of molecular chaperones in Brucella intracellular survival has been previously mentioned, but nothing was published on B. ovis in this respect, as far as we know. In the present work, in order to understand any possible contribution of the molecular chaperones DnaK and GroEL for Brucella ovis stress survival and intracellular persistance, the expression on different culture media under different stress conditions were analysed at the transcriptional and translational levels and compared with that of bacteria grown inside murine J774A.1 cells. The transcription analyses showed different levels of dnaK and groEL induction under various stress conditions (e.g., macrophages survival, acidic pH shock, high temperature, oxidative and osmotic shock) and a significant influence of the media composition. These results were consistent with the level of DnaK and GroEL expression analysed by the traditional proteomic methods. Here we demonstrate the molecular chaperones involvement in macrophage-B. ovis interaction, their expression under stress conditions suggesting the chaperones role in the bacterial resistance to such unfavourable environmental conditions.