Oral Presentation 23rd Annual Lorne Proteomics Symposium 2018

A label-free quantitative proteomics assessment of osmotic stress responses in Candida albicans (#23)

Lee Gethings 1 , Mette Jacobsen , Robert Beynon , Amy Claydon , James Langridge , Johannes Vissers3 , Alistair Brown , Dean Hammond
  1. Waters Corporation, Wilmslow, CHESHIRE, United Kingdom

The fungal pathogen Candida albicans survives in humans most commonly as a commensal organism in the flora of the gastrointestinal and urogenital tracts, occasionally causing opportunistic infections, such as thrush. However, in people who are immunocompromised, C.albicans can cause severe and life-threatening infections. Stress adaptation is critical for the pathogenicity of C.albicans, and hence has been studied in detail at the genomic level to try to assess the mechanisms for host-defence implemented as adaptations to the environments encountered. This study investigated the proteomic changes between C.albicans grown under normal conditions and those experiencing salt-stress in the growth media.

Three biological replicates of each condition (three high salt, three controls) were proteolysed with trypsin and the resulting peptides analysed using an ion mobility assisted data independent workflow (LC-IM-DIA-MS). Sample loadings of 100 ng protein on column, were separated over a 90 min linear reversed-phase LC gradient, returning in excess of 1000 protein identifications per acquisition. The data were processed using ProteinLynx Global Server software (vs.3.0.2) to identify and quantify the proteins with a label-free approach. Data were searched against a C. albicans specific database using a 1% false discovery rate (FDR). Gene ontology (GO) functional analysis of the data were queried using blastp, followed by enrichment tests and pathway analysis using R/Bioconductor package systemPipeR (vs.1.10). Data interpretation revealed that a number of central metabolic enzymes are involved with glycerol synthesis, which is a key osmolyte for C.albicans.