Pleiotropic effects of ribosomal mutations for cycloheximide resistance in a double-resistant homocaryon of Neurospora crassa.

Pleiotropic effects of two ribosomal mutations for cycloheximide resistance were studied in a double-resistant homocaryon. The results obtained indicated that the combination of the two ribosomal mutations results in: (i) morphological abnormalities which suggest a severe distortion in the extension of cell walls and membranes; (ii) disturbance in the normal 60S-40S subunit ratio; (iii) decreased rate of cell mass production not necessarily associated with inbalance in the 60S-40S ratio; and (iv) cold sensitivity which does not interfere with mycelial mass production.