Ertyhromycin as a tool for discriminating in vivo between mitochondrial and chloroplastic protein synthesis in Nicotiana sylvestris

Abstract

In plant cells it has not been possible to discriminate between mitochondrial (MPS) and chloroplastic protein synthesis (ClPS) in vivo by means of compartment specific inhibitors. In this paper data are reported about the specificity of erythromycin (ERY) which inhibited ClPS but not MPS in tissue cultures of Nicotiana sylvestris. The data supporting this conclusion are: (a) ERY produced bleaching without affecting the earlier phases of growth; (b) protein synthesis in isolated chloroplasts was inhibited by the drug, whereas protein synthesis in isolated mitochondria was almost unaffected; (c) the synthesis of cytochrome oxidase (a mitochondrial-dependent process) was unaffected by ERY; (d) electron micrographs of the ultra-thin sections of plantlets and tissue cultures showed that the structure of mitochondria was unaffected by the drug, but the structure of chloroplasts was altered completely.