Gene Expression in Bacillus subtilis Surface Biofilms With and Without Sporulation and the Importance of yveR for Biofilm Maintenance

Abstract: Five independent DNA microarray experiments were used to study the gene expression profile of a 5-day Bacillus subtilis air – liquid interface biofilm relative to planktonic cells. Both wild-type B. subtilis and its sporula-tion mutant (spoIIGB::erm) were investigated to discern the important biofilm genes (in the presence and absence of sporulation). The microarray results indicated that suspen-sion cells were encountering anaerobic conditions, and the air–liquid interface biofilmwasmetabolically active. For the statistically significant differential expression (P < 0.05), there were 342 genes induced and 248 genes repressed in thewild-type biofilm,whereas 371 geneswere induced and 128 genes were repressed in the sporulation mutant biofilm. The microarray results were confirmed with RNA dot blotting. A small portion of cells (1.5%) in the wild-typ