Visualization of actin arrays in growing hyphae of the fungusSaprolegnia ferax

Summary We have observed the distribution of filamentous actin in growing hyphae of the oomyceteSaprolegnia ferax. The actin was stained by electroporating intact hyphae in the presence of 4×10^–8 M rhodamine phalloidin. Hyphae quickly recovered from electroporation and showed an apical cap of densely packed actin filaments. The pores created by the electric shock resealed in 8–10min and within 1/2 h hyphae resumed growth and appeared normal. This technique allows us to observe actin arrays during growth and may prove to be a useful tool in determining the complex roles of actin in apical growth.Abbreviations RP rhodamine phalloidin - F-actin filamentous actin