Fig. 9. The cflB gene is necessary for correct actin localization in vegetative hyphal cells. Strains were grown for 4 days at 25°C. Actin localization was examined using immunocytochemistry. Actin is localized as cortical spots and is also concentrated at sites of polarized growth. (A) Vegetative hyphal growth at 25°C. The white arrow indicates concentrated actin at the hyphal apex, which is absent in the cflB strain. (B) Asexual development at 25°C. The single white arrow indicates actin concentrated in the newly formed conidium, the double white arrow indicates actin concentrated at the distal tip of a phialide. Conidiophore cell types are indicated (c, conidia; m, metulae; p, phialides). The cflB strain lacks actin concentrated in conidiophores. (C) Nascent septation sites in vegetative hyphae at 25°C. Concentrated actin is indicated by single white arrows (FITC panel) and double arrows indicate corresponding cell walls (CAL panel). Scale bars, 20 µm.