Cell wall defects of the sur7 Δ null mutant. Serial dilutions of overnight cultures were spotted onto different agar media and incubated for 2 days at 30°C. Strains are indicated in the top right diagram with an arrow signifying decreasing cell densities (1 × 107, 2 × 106, 4 × 105, 8 × 104 and cells ml-1) of the strains spotted onto each plate. Normal growth on YPD medium is shown in (A). YPD medium containing cell wall perturbing agents such as (B) 0.1 μg ml-1 caspofungin, (C) 0.02% SDS, (D) 200 μg/ml Congo Red, and (E) 50 μg ml-1 Calcofluor White are shown.