Studies on new aminoglycoside antibiotics, istamycins, from an actinomycete isolated from a marine environment. II. Possible involvement of plasmid in istamycin production.

Acriflavine treatment of an istamycin-producing Streptomyces tenjimariensis strain designated SS-939 resulted in a high frequency of isolates with reduced istamycin production. Some of these were shown to have lost a particular plasmid present in the parent strain. Istamycin production by these isolates was largely restored by the addition of 2-deoxystreptamine (DOS) to the medium whereas the effect of DOS was small in the strain SS-939. Sodium palmitate also stimulated production, especially when added together with DOS. These stimulative effects by DOS and palmitate, however, were not exhibited in the presence of glucose (1.0%).