Transcriptional and metabolic changes in Candida albicans during yeast-to-hypha transition

In this study hypha-associated transcriptional and metabolic changes were investigated in the opportunistich human pathogen Candida albicans. Three different strains were investigated the SC5314 wildtype and two filamentation-affected mutant strains cph1Δefg1Δ and hgc1Δ. Three different hypha-inducing conditions were compared with two respective yeast conditions: SD minimal medium with 10% human serum or N-acetylglucosamin vs. SD minimal medium, and M199 pH7.4 vs. M199 pH4. Sampling time points were 0, 90 and 240 min. ON cultures were prepared in SD and re-inoculated in SD and grown to early log-phase prior to the experiment. Cells were collected, washed and used to inoculate the test medium at OD0.3. All cultures were generally maintained at 37°C. Obtained samples were submitted for transcriptional profiling (RNA-Seq with 10 million reads per sample and 150 bp paired-ends) and metabolomics.

Media list:

SD: 2% glucose, 0.17% YNB without amino acids, 0.5% ammonium sulfate, pH 4.5

HS - SD with 10 vol% human serum (Male, AB negative)

GlcNAc - 2% N-acetylglucosamine, 0.17% YNB without amino acids, 0.5% ammonium sulfate, pH 4.5

Medium 199 with Earle's salts and L-Glu  buffered to either pH 4 or 7.4 by addition of 1/5 volume of 0.1 M citric acid and 0.2 M Na₂HPO₄ buffer