Detection and Expression of Biosynthetic Genes in Actinobacteria ...

BERVANAKIS, G.Chapter 3: RESULTS3.2.6 UV-Vis Spectroscopy of Semi-Purified AntimicrobialOrganic ExtractSemi-purified organic extracts were evaluated using UV-Vis spectroscopy todetermine if any of the metabolites contained chromophoric functional groups. Twoof the extracts from actinobacterial cultures A0350 and A1113 exhibited similar UVspectral properties, with characteristic peaks [observed between 300 nm and 400 nm withpeaks spanning approximately 20 nm apart] (Figures 35B and C) indicative of polyenecompounds (Figure 35A). It was also observed that in the UV spectrum of theseextracts an additional peak in the 400 nm – 500 nm range was also evident, which couldindicate the presence of an extended chromophore, seen in aromatic polyketides(Figure 35E).Figure 35. Spectrogram of antimicrobial semi-purified organic extract.A) Spectrum of purified polyene antibiotic (Hacene et al., 1994)., B) Semi-purifiedorganic extract of A0350 isolate., C) Semi-purified organic extract of A1113 isolate.,D) Semi-purified extract of A3675., E) Tetracenomycin C (Decker & Haag, 1995)._____________________________________________________________________107