Twenty-five soil samples were collected in the Algerian Sahara and analyzed to isolate rare actinomycetes. Eighty-six isolates with the same
Nocardiopsis or Saccharothrix morphology were isolated on humic–vitamin B agar medium using dilution techniques and several antibiotics
as selective agents. Certain of these antibiotics seemed to be very selective for some phenotypes. Morphological and chemotaxonomic
characteristics led to identifying 54 isolates belonging to the Nocardiopsis genus and 32 isolates belonging to the Saccharothrix genus. An
assessment of the antimicrobial properties of the isolates showed activities against Gram-positive bacteria, fungi and yeasts. Saccharothrix
isolates possessed better antifungal activity than Nocardiopsis. One of them, labeled SA 103, was therefore selected for identification of its
antifungal antibiotic activities. Production of overall antifungal and antibacterial activities was checked on the complex medium ISP2 and
a synthetic medium (SM) that contains glucose or starch as carbon source, and ammonium or nitrate as nitrogen source. The SM medium
containing ammonium sulfate (0.2%), supplemented with starch (0.5%) and yeast extract (0.3%), was retained for production of antibiotics.
Active substances were purified by a G25-80 Sephadex column and reverse phase HPLC. Two pure substances were obtained and named
ZA01 and ZA02; they were characterized on the basis of combined data resulting from chemical tests, UV visibile and IR spectra and mass
spectrometry. The two antibiotics were found to be related and were partially characterized as nucleotidic or nucleosidic antibiotics. Their
structures consisted of a chain of three sugar units linked to an aromatic base containing a phosphate residue.
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