DETECTION, CHARACTERIZATION, AND PHYTOTOXIC ACTIVITY OF THE NUCLEOSIDE ANTIBIOTICS, BLASTICIDIN-S AND 5-HYDROXYLMETHYL-BLASTICIDIN-S

Screening for herbicidal compounds carried out on culture broths of St reptomyces strains isolated from soil resulted in the detection of pot ent phytotoxic activity. The active principles were isolated, and iden tified as the nucleoside antibiotics Blasticidin S (Bl-S) and 5-Hydrox ymethyl-Blasticidin S (H-M-Bl-S). Bl-S was more active than H-M-Bl-S o n seedling germination in petri dishes and in postemergence greenhouse tests. Moreover both antibiotics were more phytotoxic to dicotyledono us than to monocotyledonous plants. The increased sensitivity of dicot s was confirmed in carrot and rice cell cultures. Both compounds also inhibited [C-14]amino acid incorporation into proteins of rice and car rot cell cultures. Protein synthesis was more affected in carrot than rice.