Project description:Studies on phosphatase activity of Streptomyces fradiae 3535 grown in three different media indicate that neomycin formation varies directly with enzyme activity, sodium nitrate-maltose-mineral salts medium giving the highest yields of alkaline phosphatase and neomycin. S. fradiae contains more than one alkaline phosphatase and the phosphatase responsible for hydrolysis of neomycin phosphate appears to be substrate specific. The same enzyme apparently hydrolyses both the N-P and P-O-P bonds of neomycin pyrophosphate. The enzyme is stimulated by Ca(2+), is inactive at a pH below 7 and is inhibited by EDTA. Enzymic activity increases when mycelia are incubated in mineral salts medium, but decreases when phosphate or glucose is included in the medium, although the latter is more effective. The inhibitory effect of EDTA on neomycin formation by resting mycelia is completely reversed by Ca(2+).
Project description:Some amino acids, particularly glycine and serine, favour the accumulation in the fermentation broth of three phosphorylated amino sugar compounds that are intermediates in the pathway of neomycin biosynthesis by Streptomyces fradiae 3535. The compounds were separated and purified further by Amberlite IRC-50 (NH(4) (+) form). The intermediates were characterized by physicochemical methods as neomycin B pyrophosphate (C(23)H(48)N(6)O(19)P(2),3H(2)O), neomycin C pyrophosphate (C(23)H(48)N(6)O(19)P(2),3H(2)O) and neomycin C dipyrophosphate complex (C(24)H(66)N(8)O(33)P(4)).
Project description:Capoamycin-type antibiotics (2-5) and polyene acids (6, 7) were isolated from marine Streptomyces fradiae strain PTZ0025. Their structures were established by extensive nuclear magnetic resonance (NMR) and high resolution electron spray ionization mass spectroscopy (HRESIMS) analyses and chemical degradation. Compounds 3, 4, 6, 7 were found to be new and named as fradimycins A (3) and B (4), and fradic acids A (6) and B (7). Compounds 3-5 showed in vitro antimicrobial activity against Staphylococcus aureus with a minimal inhibitory concentration (MIC) of 2.0 to 6.0 μg/mL. Interestingly, Compounds 3-5 also significantly inhibited cell growth of colon cancer and glioma with IC₅₀ values ranging from 0.13 to 6.46 μM. Fradimycin B (4), the most active compound, was further determined to arrest cell cycle and induce apoptosis in tumor cells. The results indicated that fradimycin B (4) arrested the cell cycle at the G₀/G₁ phase and induced apoptosis and necrosis in colon cancer and glioma cells. Taken together, the results demonstrated that the marine natural products 3-5, particularly fradimycin B (4), possessed potent antimicrobial and antitumor activities.
Project description:We report a draft genome sequence of Streptomyces xinghaiensis (fradiae) OlgR, which is resistant to oligomycin A. This mutant strain is derived from S. xinghaiensis OlgR2.100, which is resistant to (33S)-azido-33-deoxyoligomycin A. We have identified single nucleotide polymorphisms (SNPs) in 7 genes, which may lead to oligomycin A resistance.