1. To know the influence of IM-2 on Streptomyces sp. FRI-5, IM-2 was added at 5-h and cell growth, blue-pigment production and antibiotic production were measured. In the absence of IM-2, cell growth continued until 12-h cultivation, and no production of blue pigment was observed until 32-h cultivation. In clear contrast to it, IM-2 addition terminated cell growth immediately, and blue-pigment production was observed after 1 h of IM-2 addition. Antibiotic production was measured by B. subtilis at as test strain by cup method. In the absence and presence of IM-2, profile of clear zone was different, suggesting the production of different antibiotics.
2. An antibiotic produced in the absence of IM-2 was purified from 5-liter of culture broth after 4 purification steps : yield 13.5 mg. By NMR, IR and MS analyses, the antibiotic was identified as D-cycloserine, indicating that Streptomyces sp. FRI-5 can produce D-cycloserine in the absence of IM-2.
3. Antibiotics produced in the presence of IM-2 were purified from 25-liter of culture broth after 6 purification steps. Two antibiotics (C, D) and three relating compounds (compound A1, A2 and B) were isolate : yield 2.7, 3.0, 1.3, 1.4 and 2.4 mg for compound C, D, A1, A2 and B, respectively, By NMR, IR and MS analyses, antibiotic C and D were identified as showdomycin and minimycin, respectively. Similarly, compound A1, A2 and B were alpha-showdomycin, alpha-minimycin and 5-alpha-arabinofuranosyl-1, 3-oxazin-2, 4-dione. Therefore, Streptomyces sp. FRI-5 can be concluded to produce several nucleoside antibiotics and relating compounds in the presence of IM-2.
4. Production profiles for those antibiotics were measured in the absence and presence of IM-2. In the absence of IM-2, D-cycloserine was produced and no nucleoside antibiotics were detected, but the addition of IM-2 completely suppressed production of D-cycloserine and instead nucleoside antibiotics were produced.