pABr3 transformation, comparison of transformation efficiency with pABr1, and hygromycin transformant amplification. a) Images (100x magnification) of pABr3-transformed hyphae, at 3 days and 1 year after transformation as indicated, obtained by phase-contrast (Nomarski) and SGFP fluorescence microscopy. A negative, untransformed control (mock) is shown at the top; a merge of the two types of images is shown in the rightmost panels. b) Comparison of the transformation efficiencies obtained with pABr1 and pABr3. Data are the mean ± s.e.m. of at least five independent experiments. c) Transformed mycelia were grown on hygromycin (15 μg/ml)-supplemented medium for 60 days and then transferred to solid medium containing the indicated concentrations of hygromycin B. After 7 days, mycelia were visualized under a stereo-microscope at the indicated magnifications to detect the presence of tufts grown beyond the dotted line.