Actinomycete strain SA198, isolated from a Saharan soil sample of Algeria, exhibited antimicrobial activity against Gram-positive and Gram-negative bacteria, and phytopathogenic and toxinogenic fungi. The morphological and chemotaxonomic characteristics of the strain were consistent with those of the genus Saccharothrix. Analysis of the 16S rRNA gene sequence of strain SA198 showed a similarity level ranging between 97.2 and 98.8% within Saccharothrix species, S. australiensis being the most closely related. Two new active products were isolated by reverse HPLC using a C18 column. The ultraviolet-visible (UV-VIS), infrared (IR), mass, and (1)H and (14)C nuclear magnetic resonance (NMR) spectra showed that these products were new bioactive compounds. The minimum inhibitory concentrations of these antibiotics showed a strong activity against fungi and moderate activities against Gram-positive and Gram-negative bacteria.

International audienceAn actinomycete, designated SA181T, was isolated from Saharan soil in the Hoggar region (south Algeria) and was characterized taxonomically by using a polyphasic approach. The morphological and chemotaxonomic characteristics of the isolate were consistent with the genus Saccharothrix, and 16S rRNA gene sequence analysis confirmed that strain SA181T was a novel member of the genus Saccharothrix. DNA–DNA hybridization values between strain SA181T and its closest phylogenetic neighbours, the type strains of Saccharothrix longispora, Saccharothrix texasensis and Saccharothrix xinjiangensis, were clearly below the 70 % threshold. The genotypic and phenotypic data showed that the isolate represents a novel species of the genus Saccharothrix, for which the name Saccharothrix hoggarensis sp. nov. is proposed, with the type strain SA181T ( = DSM 45457T  = CCUG 60214T)

Actinomycete strain SA198 T , isolated from a Saharan soil sample of Algeria, was characterized taxonomically by using a polyphasic approach. Chemotaxonomic and morphological characteristics observed suggested that it was a member of the genus Saccharothrix. The 16S rRNA gene sequence analysis confirmed that strain SA198 T was a member of the genus Saccharothrix and showed a similarity level ranging between 97.5 and 98.9 % within species of the genus Saccharothrix, Saccharothrix australiensis being the most closely related. However, DNA-DNA hybridization values between strain SA198 T and its closest phylogenetic neighbours, the type strains of S. australiensis, Saccharothrix xinjiangensis, Saccharothrix algeriensis and Saccharothrix espanaensis, were clearly below the 70 % threshold. Based upon genotypic and phenotypic differences from other members of the genus, a novel species, Saccharothrix tamanrassetensis sp. nov., is proposed, with SA198 T (5DSM 45947 T 5CECT 8640 T) as the type strain.

The taxonomic position of a novel actinomycete, strain SA152 T , isolated from a sample of Algerian Saharan soil, was determined using a polyphasic taxonomic approach. The strain produced abundant aerial mycelium and fragmented substrate mycelium on most media tested. Chemotaxonomically and phylogenetically, the strain was related to the members of the genus Saccharothrix. Results of 16S rRNA gene sequence comparison revealed that strain SA152 T shared the highest degree of 16S rRNA gene sequence similarity with Saccharothrix xinjiangensis NBRC 101911 T (99.3 %) and Saccharothrix texasensis NRRL B-16134 T (98.9 %).However, DNA-DNA hybridization studies showed only 16.2 % relatedness with S. xinjiangensis DSM 44896 T and 33.9 % relatedness with S. texasensis DSM 44231T . Based upon genotypic and phenotypic differences from other members of the genus, a novel species, Saccharothrix saharensis sp. nov., is proposed, with SA152 T (5DSM 45456 T 5CCUG 60213 T ) as the type strain.The genus Saccharothrix was described by Labeda et al. (1984) for actinomycete strains that were characterized by fragmentation of both the substrate and aerial mycelia into rods and ovoid elements, a type-III cell wall, containing meso-diaminopimelic acid without glycine, galactose, rhamnose and small amounts of mannose as diagnostic whole-cell sugars, a phospholipid type PII (phosphatidylethanolamine) or PIV (phosphatidylethanolamine and phospholipids containing glucosamine) pattern (Labeda & Lechevalier, 1989) and MK-9(H 4 ) as the predominant menaquinone, while mycolic acids are absent (Labeda & Kroppenstedt, 2000). In recent years, several Saccharothrix strains have been transferred to other new taxa, including the genera Lentzea (Yassin et al., 1995), Crossiella (Labeda, 2001), Lechevalieria (Labeda et al., 2001), Goodfellowia (Labeda & Kroppenstedt, 2006) and Umezawaea (Labeda & Kroppenstedt, 2007). At the time of writing, the genus Saccharothrix includes 13 recognized species.In the course of isolation of Saharan actinomycetes, several novel strains and species of Saccharothrix have been isolated from Algerian Saharan soil, such as Saccharothrix algeriensis DSM 44581T (Zitouni et al., 2004a) and Saccharothrix hoggarensis DSM 45457 T (Boubetra et al., 2013). Furthermore, many of these strains were shown to produce interesting antibiotics such as mutactimycins (Zitouni et al., 2004b), dithiolopyrrolones (Bouras et al., 2008) and chloramphenicol (Aouiche et al., 2012). The present study is a part of the same programme to investigate the diversity of actinomycetes in these extreme conditions. Strain SA152T was isolated from a soil sample collected from Adrar palm grove in southern Algeria, by a dilution agar plating method using humic acid-vitamins agar medium (Hayakawa & Nonomura, 1987) supplemented with cycloheximide (50 mg ml -1 ). The micro-organism was maintained on ISP 2 agar slopes at room temperature and as 20 % (v/v) glycerol suspensions at 220 u C.Cultural characteristics were investigated on media from the International Strep...

The taxonomic position of a novel actinobacterium, strain 169T , isolated from a sample of Algerian Saharan soil, was determined using a polyphasic taxonomic approach. The aerial mycelium produced non-motile, round-to oval-shaped spores, with a smooth surface, which were sessile or carried by short sporophores. Chemotaxonomically, isolate 169 T showed the same results as members of the genus Streptosporangium, but madurose, the so far diagnostic sugar of the genus, was not detected in the whole-cell hydrolysate. Despite the absence of sporangia, the 16S rRNA gene sequence analysis confirmed that strain 169 T was a member of the genus Streptosporangium. Strain 169 T was most closely related to Streptosporangium jomthongense NBRC 110047 T (99.3 % 16S rRNA gene sequence similarity), which is the only non-sporangia-forming species reported among the genus. However, DNA-DNA hybridization studies with this species showed 60 % relatedness. Based upon genotypic and phenotypic data, a novel species, Streptosporangium algeriense sp. nov., is proposed, with 169 Streptosporangium, the type genus of the family Streptosporangiaceae, was proposed by Couch (1955) for the actinobacteria producing aerial mycelium with spherical sporangia that enclose non-motile sporangiospores. These sporangia are produced by 21 species of the genus Streptosporangium. However Intra et al. (2014) described a novel species of this genus with single roundish, smoothsurfaced-spores, which were formed through the intermediary of very short sporophores on aerial hyphae. This novel species, unlike the other members of the genus Streptosporangium, does not produce sporangia. Chemotaxonomically, the genus Streptosporangium is characterized by the presence of meso-diaminopimelic acid in the cell wall and madurose in the whole-cell hydrolysates, di-and tetrahydrogenated menaquinones with nine isoprene units, phosphatidylethanolamine and phospholipids containing glucosamine as diagnostic phospholipids, and complex mixtures of iso-, anteiso-, saturated, unsaturated and 10-methylbranched fatty acids (Quintana & Goodfellow, 2012).During taxonomic and antibiotic studies of Saharan actinobacteria, strain 169 T was isolated from a Saharan soil sample collected from Adrar palm grove in southern Algeria (latitude 278 539 N, longitude 08 169 E, altitude 262 m) by a dilution agar plating method using chitinvitamin agar medium (Hayakawa & Nonomura, 1987) supplemented with actidione (50 mg ml 21 ). The presence of members of the genus Streptosporangium in these soils has already been reported (Boudjella et al., 2006). The aim of this study was to identify strain 169 T , which represents a novel species within the genus Streptosporangium, by using phenotypic, genotypic and phylogenetic approaches.Cultural characteristics were investigated on media from the International Streptomyces Project (ISP) (Shirling & Gottlieb, 1966), nutrient agar and Bennett's agar (Waksman, 1961 aerial mycelia and any soluble pigments produced were determined according to the ISCC-NBS centroid ...

During a screening for the diversity of actinobacterial strains from Saharan soil samples collected from Béchar region (Algeria), one strain designated KB-T3 was isolated by dilution technique on chitin-vitamins agar medium. The taxonomic position of this strain was determined by using a polyphasic approach. Morphological and chemical characteristics of the KB-T3 strain were consistent with those of the genus Thermobifida. The KB-T3 strain had a white aerial mycelium with dictomically branched sporophores carrying coccoid secluded spores. The substrate mycelium was pale yellow, sterile, and non-fragmented. The strain is characterized by the presence of meso-diaminopimelic acid in the cell wall, the galactose in whole-cell, and phosphatidylethanolamine in the cell membrane. The unique characteristic of this strain was its abundant growth with the absence of NaCl and in temperature‎ ranging from 40 to 65 °C, its capacity to decompose acetate, and its ability to use fructose, glucose and xylose as sole carbon source. Phylogenetic analysis based on 16S rRNA gene sequence revealed that the strain KB-T3 should be classified in the genus Thermobifida and exhibited 99.79 % gene sequence similarity to Thermobifida fusca NBRC 14071T.