Microscopic analysis reveals altered biofilm structures. Analogues that lead to reduced C. albicans biofilm formation in the XTT assay (1, 2, 3, 4, 6, 7, 9, 12, and 15) exhibit compromised biofilm structures. Filamentous C. albicans biofilm in the presence of analogues (100 μM) was stained for chitin and cellulose (calcofluor; blue); lectins that bind to sugars, glycolipids, and glycoproteins (concanavalin A; green); and live/dead cells (FUN-1; red).