9 by Springer-Verlag 1980 Effects of Cytocha las ins on Neurospora r

Growth of various strains of Neurospora crassa in the continued presence of cytochalasins A and B results in the following pattern. At low concentration the drugs cause an increase in branching which, depending on the strain, may also reveal an increase in dry weight. In-creasing the concentration results in abnormal hyphae (swollen, irregular) and eventually in inhibition of growth. Most strains are inhibited at 10-20 ~xg/ml cytochalasin A. Ultrastructure of hyphae grown in the presence of cytochalasin A reveals the presence of abnormal wall deposits. These deposits are not observed in cultures grown with cytochalasin B which gener-ally causes a lower growth response also