Candida albicans DOPA-grown cells

The fungal pathogen Candida albicans produces dark-pigmented melanin when grown in a basal medium containing 1 mM l-DOPA as melanin substrate. In the widely used C. albicans strain SC5314, melanin appeared after 3-4 days of incubation in l-DOPA medium. The experiment was designed to reveal cadidate genes associated with melanin biosynthesis by expression profiling at different times of growth with and without L-DOPA added to the medium. Expression profiling of C. albicans revealed very few genes significantly up- or down-regulated by growth in l-DOPA. Sixteen paired samples were submitted to dual channel analysis. Four biological replicate samples of RNA were prepared from cells of C. albicans strain SC5314 at four time points, from cultures grown with and without addition of 1 mM L-DOPA, thus generating an initial total of 32 samples for analysis: four experimental and four control samples made after 6 h, 24 h, 48 h and 72 h of growth. For each time point the control (no L-DOPA) samples were pooled and labelled with Cy3-dUTP by reverse transcription. The four individual biological replicates for each time point were separately labelled with Cy5-dUTP by reverse transcription and independently hybridized against the pooled controls on the microarray chips. Results were read with a ScanArray 4000 Microarray Analysis System.