Proteome analysis of Mycoplasma fermentans cultured under aerobic and anaerobic conditions

Abstract

Mycoplasmas are ubiquitous pathogens found not only in humans but also in animals, plants, insects and soil. Though they usually grow better in an aerobic environment, mycoplasmas are also facultative anaerobic microorganisms. Following infection, the transition of a microorganism from a normal environment into an anaerobic one (e.g. dead or dying tissue) may result in production of a higher number of bacterial toxins. The resolution of the bacterial proteome during the aerobic/anaerobic switch could thus allow the identification of potential pathogenic determinants and pathways. We used two-dimensional gel electrophoresis (2-DE) coupled with matrix-assisted laser desorption/ionization time-of-flight/tandem mass spectroscopy (MALDI-TOF MS/MS) and subsequent mass spectrometric analysis to characterize the liposoluble and hydrosoluble protein fractions of a strain of Mycoplasma fermentans isolated in our lab (MFI), that was cultured under either aerobic or anaerobic conditions. We identified the 27 most abundant proteins in the liposoluble fraction and the 30 most abundant proteins in the hydrosoluble fraction and determined their modulation under aerobic and anaerobic growth. By using Protein ANalysis TrougH Evolutionary Relationships (PANTHER) and the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) software analysis tools, we were able to identify, define and organize the function of each protein, as well as to determine the specific interactome. Our work provides the first proteome reference map of Mycoplasma fermentans obtained under aerobic and anaerobic growing conditions. These data may help to better understand the mechanisms of pathogenicity of this microorganism and define new diagnostic targets.