A new actinomycete strain designated Sg 10, producing antimicrobial substances was isolated from an Algerian soil. Morphological and chemical studies indicated that strain Sg 10 belonged to the genus Streptosporangium. The comparison of its physiological characteristics with those of known species of Streptosporangium showed significant differences with the nearest species Streptosporangium carneum. Analysis of the 16S rDNA sequence of strain Sg 10 showed a similarity level ranging between 96.3% and 97.8% within Streptosporangium species, with S. carneum the most closely related. However, the phylogenetic analysis indicated that strain Sg 10 represent a distinct phyletic line suggesting a new genomic species. The antimicrobial activity of strain Sg 10 showed an antibacterial activity against Gram-positive bacteria as well as an antifungal one. Four active products were isolated from the culture broth using various separation procedures. On the basis of UV-VIS spectrometry, infrared spectroscopy and chemical revelations, the antibiotics were classified in the group of glycosylated aromatics.

Aims:  Identification of a new actinomycete strain Sg3, belonging to the genus Streptosporangium and partial characterization of the produced antibacterial activities. Methods and Results:  The strain Sg3 was isolated from an Algerian Saharan soil and identified by morphological, chemotaxonomic and phylogenetic analyses to the genus Streptosporangium. The comparison of its physiological characteristics with those of known species of Streptosporangium showed significant differences with the nearest species Streptosporangium carneum. Analysis of the 16S rDNA sequence of strain Sg3 showed a similarity level ranging between 97% and 98·8% within Streptosporangium species, with S. carneum the most closely related. Strain Sg3 showed a red coloured antibacterial activity against gram‐positive bacteria on several culture media. The purification of the red pigment by chromatographic methods led to the isolation of three active products. The 1H nuclear magnetic resonance (NMR), mass, infrared (IR) and ultraviolet‐visible (UV‐VIS) data of these molecules strongly suggested that they belonged to the quinone‐anthracycline group with three or more rings. Conclusions:  Strain Sg3 represents a distinct phyletic line suggesting a new genomic species. It produces antibacterial activities identified as quinone‐anthracycline aromatics. Significance and Impact of the Study:  The quinone‐anthracycline antibiotics are known for their antimicrobial and antineoplastic activities and are used in chemotherapy for the treatment of many cancer diseases. The present work constitutes the first stage of a whole series of studies to be realized on these antibiotics before arriving at a possible application.

The presence of Aspergillus section Flavi and aflatoxin (AF) contamination was investigated in 112 samples of peanuts, almonds and dried figs collected in Algeria. The occurrence of aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) in different commodities has been determined with a sensitive method based on high performance liquid chromatography (HPLC) coupled with fluorescence detection with post-column photochemical derivatisation. Analytical results indicated that 28 samples of peanuts, 16 samples of almonds and 26 samples of dried figs contained detectable levels of AFs. A total of 69 samples (61.6%) were contaminated with AFB1 ranging from the limit of quantification to 174 µg kg. AFB2 was found in 12 samples (10.7%) and varied from 0.18 to 193 µg kg. Seven samples revealed AF concentrations lower than the limit of quantification. Eleven peanut and fourteen dried fig samples exceeded the European maximum limits for AFB1.

n a continuing search fornew antimicrobial products from actinobacteriacollected in Algerian Saharan soils, an isolateof actinobacteria,designated Sg163, was selected for its interesting antimicrobial activity.The isolate wasidentified to the genus Streptosporangium by phenotypicand molecular criteria. The cultural and physiological characterizations as well as phylogenetic analysis indicated that the isolate was different from known members of the genus Streptosporangium. Analysis of the 16S rRNA sequence showed 97.09to 98.27% similarity with those of Streptosporangium type strains. The strainSg163 produced antifungal and antibacterial activities on several culture media. The highest antimicrobial activities were obtained in ISP2 medium. Three active products C1, C2 and C3 with both antifungal and antibacterial activities were isolated and purified by chromatographic methodswith C2, as the major compound. The data of the infraredspectroscopy andthe chemical revelations, suggested that the active molecules were glycosylatedaromaticcompounds.

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