Proteomics and Lipidomics Investigations to Decipher the Behavior of Willaertia magna C2c Maky According to Different Culture Modes

Abstract

Willaertia magna C2c Maky is a free-living amoeba that has demonstrated its ability to inhibit the intracellular multiplication of some Legionella pneumophila strains, which are pathogenic bacteria inhabiting the aquatic environment. The Amoeba, an industry involved in the treatment of microbiological risk in the water and plant protection sectors, has developed a natural biocide based on the property of W. magna to manage the proliferation of the pathogen in cooling towers. In axenic liquid medium, amoebas are usually cultivated in adhesion on culture flask. However, we implemented a liquid culture in suspension using bioreactors in order to produce large quantities of W. magna. In order to investigate the culture condition effects on W. magna, we conducted a study based on microscopic, proteomics and lipidomics analyzes. According to the culture condition, amoeba exhibited two different phenotypes. The differential proteomics study showed that amoebas seemed to promote the lipid metabolism pathway in suspension culture, whereas we observed an upregulation of the carbohydrate pathway in adherent culture. Furthermore, we observed an over-regulation of proteins related to the cytoskeleton for W. magna cells grown in adhesion. Regarding the lipid analysis, suspension and adhesion cell growth showed comparable lipid class compositions. However, the differential lipid analysis revealed differences that confirmed cell phenotype differences observed by microscopy and predicted by proteomics. Overall, this study provides us with a better insight into the biology and molecular processes of W. magna in different culture lifestyles.

Keywords: Willaertia magna C2c Maky; amoebas; culture; lipidomics; metabolism; proteomics.

Figure 1

Morphology of Willaertia magna cultivated under two different culture conditions. In (A,B): W. magna is cultivated in adhesion on cell culture flask. In (C,D): W. magna is cultivated in suspension in bioreactor. Pictures were obtained with emission Scanning Electron Microscope SU5000 (Hitachi, Japan). Bar scales are represented on picture.

Figure 2

Representation of differently regulated proteins (DRPs) matching with a function in the Cluster of Orthologous Group of proteins (COG) database.

Figure 3

Gene Ontology (GO) distribution plotted by WEGO. The proteins were assigned to three main categories: biological process, molecular function and cellular component. The right-hand y-axis indicates the number of annotated proteins. The left-hand y-axis indicates the percentage of annotated proteins.

Figure 4

Representation of DRPs matching with a function in the Kyoto Encyclopedia of Genes and Genomes Pathway (KEGG) database. Each protein was classified in a KEGG category.