Since cells in the batch cultures germinate and also exhibit cohesive (cell to cell) interactions we reasoned that genes differentially regulated

in the biofilm to batch comparison and the time course analysis might contain a subset of genes involved more specifically in the detachment process, rather than exclusively in morphogenesis or cell to cell cohesion. It is conventional to Selleckchem LDK378 compare biofilm and planktonic cultures in microarray analyses, where the planktonic culture(s) serves as a sort of reference [30, 33, 38]. We compared 1 h and 3 h biofilm and batch cultures to each other since these time points bracketed the abrupt transition in which strong adhesion was lost. We used the 1h F biofilm for this comparison since we were selleck chemical attempting to uncover genes

involved in mediating adhesive interactions. Figure 8 Cell aggregate formation in batch cultures; we did not observe alignment of germ tubes extending into the surrounding medium at the edge of any of the cell aggregates. The categories of genes that were differentially regulated between the biofilm and batch cultures are summarized in Table 4. (The complete list of differentially regulated genes is given in Additional file 2). In general, genes coding for proteins involved in glycolysis, fermentation and ergosterol synthesis were upregulated while genes associated with oxidative phosphorylation and the TCA cycle were downregulated. This pattern of differential gene expression is very similar to that observed in comparisons of batch cultures grown under aerobic selleck and relatively anaerobic

conditions [39] and indicates that biofilm cells were responding to hypoxia (Figure 9). The batch comparison data were ordered with respect to the ratio of the fold changes at the 3 h and 1 h time points. There were 16 genes for which this ratio was greater than 1.5 or less than 0.66 and also appeared in the list of significantly regulated genes in the time course analysis. The 11 genes for which the ratio (3 h/1 h) was greater than 1.5 exhibited a pattern of expression that was fairly tightly clustered, similar to the group 4 pattern found by K means analysis (data not shown). Among these 11 genes were four which coded for proteins involved in response to stress: ASR1, CDR4, orf19.822 and AMS1. Table 4 Summary of differentially Resveratrol regulated genes in the biofilm-batch comparison Process GO Term Genes on microarray dataset Annotated Genes1 P value   1h-biofilm 3h-biofilm   1h-biofilm 3h-biofilm Up regulated genes 130 127       Lipid metabolism 21 18       Ergosterol biosynthesis 11 9 28 1.82 E-10 6.67 E-08 Fatty acid metabolism 3 4 74 0.2 0.1 Other lipid metabolism 7 5 – - – Glycolysis 13 7 16 5.74 E-18 1.75 E-07 Fermentation 3 2 16 0.01 0.07 Amino acid biosynthesis 11 5 205     Glutamate 5 1 13 2.37 E-05 0.27 Leucine 2 0 5 8.21 E-03 – Other 4 4 – - – Transport 12 4       Glucose transport 5 0 21 3 E-04 – Oligopeptide transport 3 0 11 3 E-03 – Other 4 4 – - – Cell wall 8 8 92 4.5 E-03 7.