Browsing by Author "Lamia Benredjem"

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    Antibacterial Properties of Leaves and Peels Extracts of Citrus aurantifolia cultivated in Algeria against Multi-Drug Resistant Staphylococcus aureus Originating from Raw Milk
    (Tropical Journal of Natural Product Research, 2023-11-01) Lamia Benredjem
    Plants have an increased consumer preference and acceptability for the treatment of several diseases. Here, the antibacterial properties of organic extracts obtained from leaves and peels of Citrus aurantifolia from Algeria have been characterized. Two solvents, methanol, and ethanol, were employed to extract the bioactive components. Quantitative analysis of total phenols and flavonoids was conducted for the different extracts. The antibacterial activity was tested against multidrug-resistant Staphylococcus aureus strains originating from raw milk and reference strains including Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, and Bacillus cereus ATCC 11778. The results revealed that leaves and peels extracts displayed significant antibacterial activity against the tested bacteria. The inhibition zone diameters observed ranged from 16.00 mm to 22.00 mm. The highest antimicrobial effect was observed with the ethanol extracts against the multidrug-resistant S. aureus strains, as indicated by a minimum inhibitory concentration of 1.56 mg/ml. The highest total phenolics and flavonoids contents were found to be 96 mg GAE/g and 54 mg QE/g in peels. Hence, the reported results unveil valuable insights into the antibacterial effects of Citrus aurantifolia extracts which have potential antimicrobial applications.
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    First Polyphasic Study of Cheffia Reservoir (Algeria) Cyanobacteria Isolates Reveals Toxic Picocyanobacteria Genotype
    (microorganisms, 2023-10-30) Lamia Benredjem
    Abstract: Monitoring water supply requires, among other quality indicators, the identification of the cyanobacteria community and taking into account their potential impact in terms of water quality. In this work, cyanobacteria strains were isolated from the Cheffia Reservoir and identified based on morphological features, the 16S rRNA gene, phylogenetic analysis, and toxin production by polymerase chain reaction PCR screening of the genes involved in the biosynthesis of cyanotoxins (mcyA, mcyE, sxtA, sxtG, sxtI, cyrJ, and anaC). Thirteen strains representing six different genera: Aphanothece, Microcystis, Geitlerinema, Lyngbya, Microcoleus, and Pseudanabaena were obtained. The results demonstrated the importance of morphological features in determining the genus or the species when incongruence between the morphological and phylogenetic analysis occurs and only the utility of the 16S rRNA gene in determining higher taxonomic levels. The phylogenetic analysis confirmed the polyphyly of cyanobacteria for the Microcystis and Oscillatoriales genera. Unexpectedly, Aphanothece sp. CR 11 had the genetic potential to produce microcystins. Our study gives new insight into species with picoplanktonic (or small) cell size and potentially toxic genotypes in this ecosystem. Thus, conventional water treatment methods in this ecosystem have to be adapted, indicating the requirement for pre-treatment methods that can effectively eliminate picocyanobacteria while preserving cell integrity to prevent toxin release.