Sisomicin 생산균인 Micromonospora inyoensis 균주를 변이유기체로 처리하였을 때 활성이 높은 균주들을 얻기 위한 최적조건으로는 각각 자외선(UV light) 처리에서 90％, nitrosoguanidine(NTG)에 대해 99％, nitrous acid에 대해 99.3％의 사멸율을 나타내는 경우였다. 이 때 분리된 colony들의 sisomicin생성능의 측정은 액체배양 대신 쉽고 간편한 agar plug법을 사용하였다. 한편, 변이유기제로 처리한 후 우량균주를 선택적으로 분리하기 위한 방법으로 aminoglycoside계통의 항생물질 혹은 중금속염을 함유한 농도구배 agar plate에서 생성된 균주들의 화성을 살펴본 결과, 항생물질로서는 gentamicin, kanamycin 이, 중금속염으로서는 Co, Hg가 효과적이었다.
A sisomicin-producing strain, Micromonospora inyoensis, was treated with various mutagens. The optimal death rates to obtain the high-producers of sisomicin were 90% for ultraviolet light, 99% for nitrosoguanidine, and 99.3% for nitrous acid, respectively. In place of the method of liquid culture, an agar plug method, which is easy and convenient, was used to measure the antibiotic-producing abilities of the strains isolated from mutagen-treated cells. On the other hand, as the selection method of overproducing mutants after mutagenesis, gradient agar plates which included various antibiotics and salts were used. Among the antibiotics and salts tested, gentamicin and kanamycin as antibiotics, and CuCl$_2$ and HgCl$_2$ as salts, were effective to select the high-producers of sisomicin.
