Browsing by Author "Youcef, Khadidja Oulad Hadj"

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    Diversity and bioactivity of endophytic actinobacteria associated with the roots of artemisia herba-alba asso from Algeria
    (Springer , 2024-12-01) Djemouai, Nadjette; Meklat, Atika; Youcef, Khadidja Oulad Hadj; Nacer, Asma; Saadi, Sid Ahmed; Verheecke-Vaessen, Carol
    The isolation of endophytic actinobacteria from the roots of wild populations of Artemisia herba-alba Asso, a medicinal plant collected from the arid lands of Algeria, is reported for the first time. Forty-five actinobacterial isolates were identified by molecular analysis and in vitro evaluated for antimicrobial activity and plant growth-promoting (PGP) abilities (1-Aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, nitrogen fixation, phosphate and potassium solubilization, ammonia, and siderophores production). The phylogenetic relationships based on 16S rRNA gene sequences show that the genus Nocardioides (n = 23) was dominant in the sampled localities. The remaining actinobacterial isolates were identified as Promicromonospora (n = 11), Streptomyces (n = 6), Micromonopora (n = 3), and Saccharothrix (n = 2). Only six (13.33%) strains (five Streptomyces and one Saccharothrix species) were antagonistic in vitro against at least one or more indicator microorganisms. The antimicrobial activity of actinobacterial strains targeted mainly Gram-positive bacteria. The results demonstrate that more than 73% of the isolated strains had ACC deaminase activity, could fix atmospheric nitrogen and were producers of ammonia and siderophores. However, only one (2.22%) strain named Saccharothrix sp. BT79 could solubilize phosphorus and potassium. Overall, many strains exhibited a broad spectrum of PGP abilities. Thus, A. herba-alba provides a source of endophytic actinobacteria that should be explored for their potential biological activities.
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    Streptomyces species from the rhizosphere of the medicinal plant Artemisia herba-alba Asso: screening for biological activities
    (Springer, 2022-05-02) Djemouai, Nadjette; Meklat, Atika; Gaceb-Terrak, Rabéa; Youcef, Khadidja Oulad Hadj; Nacer, Asma; Saadi, Sid Ahmed; Saad, Somia; Verheecke-Vaessen, Carol; Bouras, Noureddine
    This work aims to study cultivable actinobacterial isolated from the rhizosphere soil of Artemisia herba-alba Asso; an important component of the Mediterranean dry steppe flora. The isolates functional attributes with respect to antifungal, in vitro growth-promotion properties and enzymatic capacities, were studied. A total of eleven cultivable actinobacterial strains were isolated and identified as Streptomyces species by 16S rRNA gene sequencing. The eleven Streptomyces strains were positive for the production of almost all the hydrolytic enzymes tested, while the majority had ACC deaminase activity (6 strains) and exhibited ammonia (7 strains), siderophores production (9 strains) and phosphate solubilization (6 strains). Two out of the eleven strains named Streptomyces sp. BKS30 and BKS40 showed antifungal activities. One promising Streptomyces sp. strain BKS30 that was in-depth characterized morphologically and biochemically was further tested for its antifungal activity for the filtrate and the butanolic extract against nine target-fungi as well as for its antioxidant activity by DPPH and ABST tests. The obtained results demonstrate that Streptomyces species isolated from the rhizosphere of Artemisia herba-alba Asso have the potential for different biological activities including antifungal and antioxidant activities particularly for strain BKS30.