http://dspace.univ-setif.dz:8888/jspui/handle/123456789/51 2026-04-30T02:50:41Z 2026-04-30T02:50:41Z Selloum, Mounir http://dspace.univ-setif.dz:8888/jspui/handle/123456789/6643 2026-03-16T09:15:57Z 2026-01-01T00:00:00Z

Titre: Activités antimicrobienne et antioxydante des extraits de Ruta chalepensis L. Auteur(s): Selloum, Mounir Résumé: The aim of this study is to determine the chemical composition, phenolic content, as well as the antibacterial, antifungal and antioxidant activities of hydromethanolic extracts from R. chalepensis collected at three different periods: before flowering (BF), during flowering (DF) and after flowering (AF). Three hydromethanolic extracts were prepared: the before flowering extract (BFE), during flowering extract (DFE) and after flowering extract (AFE). Hydromethanolic extracts analysis was conducted regarding their chemical composition by HPLC-DAD-ESI/MS method, quercetin, graveolin, bergapten, isoimperatorin, chalepin, rutamarin and β-carotene were detected. Also, total phenolics and flavonoids contents were determined. The AFE displayed the maximum polyphenol and flavonoid levels; 84.54 ± 1.66 µg GAE/mg dry extract and 25.15 ± 0.88 µg QE/mg dry extract, respectively. Antibacterial activity was evaluated against seven bacterial strains using disc diffusion (DD) method and minimal inhibitory concentration (MIC). The results of the studied plant showed an important antibacterial activity against both Gram-negative and Gram-positive bacteria. The bacterial strains showed sensitivity ranging from moderate to high, either in terms of ID (08.67 to 17.67 mm) or in terms of MIC (01.95 and 31.25 mg/ml). These extracts also exhibited excellent activity against eight filamentous fungi growth when tested by incorporation of plant extracts into the culture medium method at (10%) reduced the growth from 25 % to 97% of all fungi. On the other hand, The antioxidant activity was assessed using four methods; DPPH ,with IC50 ranging between 14.18 ± 1.02 and 30.96 ± 1.80 μg/mL, β-carotene/linoleic acid, with IC50 ranging between 34,86 ± 0,78 and 49,06 ± 0,15 μg/ml and reducing power, with EC50 varied between 100,61± 1,25 and 139,99± 2,08 µg/ml and TAC, with values ranging between 125,12 ± 2,47 and 160.59 ± 5.78 µg AAE/mg extract. In conclusion, the results revealed that R. chalepensis hydromethanolic extracts have strong antibacterial and antioxidant properties, highlighting their potential as natural sources for developing novel antibacterial and antioxidant agents.

2026-01-01T00:00:00Z KHITHER, Hanane http://dspace.univ-setif.dz:8888/jspui/handle/123456789/6596 2026-01-19T12:03:39Z 2025-01-01T00:00:00Z

Titre: IMMUNOLOGY : Course intended for L2 Biology Auteur(s): KHITHER, Hanane Résumé: Immunology is the branch of biology that studies the functioning of the immune system in both physiological and pathological contexts. It enables the investigation of the properties of immune effectors and their targets both in vivo and in vitro. The immune system comprises organs, tissues, cells (such as T and B lymphocytes, macro- phages, and leukocytes), and molecules (including antibodies and interleukins) that partici- pate in immunity. Lymphoid organs and tissues are distributed throughout the body. Immune cells circulate within and between these organs via blood and lymph. They communicate either through direct contact (receptor–ligand interactions) or at a distance via secreted molecules (media- tor–receptor interactions). These soluble, secreted molecules are called cytokines substances produced by certain immune cells that act on other immune cells to regulate their activity. This general term encompasses lymphokines, monokines, chemokines, and interleukins.

2025-01-01T00:00:00Z Gharzouli, Merihane http://dspace.univ-setif.dz:8888/jspui/handle/123456789/6564 2025-12-17T11:03:53Z 2025-01-01T00:00:00Z

Titre: Application of bioactive compounds in food bio-preservation and infection protection Auteur(s): Gharzouli, Merihane Résumé: Fungal contamination of citrus crops represents a significant issue in Algeria. The primary aim of this study is to limit fungal growth on orange fruits using the nanoemulsions obtained from plants of Origanum majorana, Citrus limon, Cymbopogon citratus and Foeniculum vulgare. The essential oils from these plants were extracted using hydrodistillation method, and their nanoemulsions were produced using ultrasonication method. The chemical composition was analyzed using a GC-MS system, and the physicochemical properties of the nanoemulsions were assessed. The antimicrobial efficacy was evaluated in vitro. Furthermore, the antifungal potential of marjoram and fennel was assessed in silico. The GC-MS analysis demonstrated that the nanoemulsification increases the concentrations of terpinen-4-ol and cis-β-terpineol in marjoram, as well as estragole and anethole in fennel, in addition to neral and geranial in both lemon and lemongrass oils, while reducing the levels of α-terpinene, fenchone, limonene, γ-terpinene, and β-myrcene. The nanoparticles exhibited a narrow particle size distribution, indicating high stability and monodispersity of the nanoemulsions. The TEM imaging of the nanoemulsions showed a spherical morphology with diverse nanometer-scale dimensions. The molecular and the phylogenetic analysis of the isolated fungi from orange fruits showed 100% homology to P. expansum and P. digitatum. the essential oils exhibited greater potency compared to their nanoemulsions, with MIC values spanning from 2% to 0.12% against bacteria and from 1% to 0.03% against fungus. Furthermore, the majority of the tested fungi were completely inhibited by lemongrass. On the other hand, F. vulgare showed the weakest antimicrobial activity. Strong binding-free energy values were observed in the interactions between essential oil or nanoemulsions and fungal enzymes, with notable docking scores (−6.6 to −7.0 kcal/mol) for aromatic components. The application of nanoemulsified marjoram, lemon and lemongrass as a coating on orange fruits significantly inhibit the growth of P. expansum and P. digitatum molds compared to uncoated samples. The use of nanoemulsions minimize negative changes in quality parameters of orange fruits throughout storage, encompassing titratable acidity (TA), pH, total soluble solids (TSS), ascorbic acid concentration, weight loss and firmness. The nanoemulsified O. majorana and C. limon did not influence the sensory attributes of the coated fruits as compared to the C. citratus nanoemulsion. Overall, the tested nanoemulsions demonstrated their high efficacy in managing pathogens affecting orange fruits.

2025-01-01T00:00:00Z Kara, Anfal http://dspace.univ-setif.dz:8888/jspui/handle/123456789/6154 2025-10-29T13:14:30Z 2025-10-29T00:00:00Z

Titre: Study of the prevalence of antibiotic-resistant bacterial strains of clinical origin in the region of Sétif and molecular characterization of their resistance Auteur(s): Kara, Anfal Résumé: Antibiotic resistance (AR) is among the leading global health concerns to date. In our study, 402 strains were collected from 7 medical diagnostic laboratories and 3 government hospitals in Sétif region over three years (2021-2023). First, the identification of 326 clinical community samples and 76 hospitalized samples, isolated from different specimens, was carried out using microbiological and biochemical tests and confirmed by API gallery. This analysis identified 10 species belonging to Gram negative bacteria (GNB) and 3 species belonging to Gram positive bacteria (GPB). E. coli was the predominant pathogen among GNB (50%) while S.aureus was the most common GPB (7.7%). The majority of these strains were found in urine samples from adult patients. Antibiotic susceptibility tests and MICs were performed according to CA-SFM recommendations. A significant proportion of the identified strains exhibited high resistance rates against first-line antibiotics commonly used in the treatment of various bacterial infections including penicillins and cephalosporins, but a substantial resistance was recorded against imipenem in E. coli (49.8%) and Proteus species (32.1%).Similarly, tobramycin and gentamycin exhibited limited effectiveness against P. aeruginosa, Enterobacter spp., (20% to100%) and all GPB. MDR strains represented 56% of all tested isolates, followed by XDR (26.1%). Amikacin was the most effective antibiotic. Among K. pneumoniae isolates, 66.6% were classified as hypervirulent K. pneumoniae (hvKp) based on the string test. In S. aureus species, 61.3% were methicillin-resistant S. aureus (MRSA), while 9.7% exhibited the constitutive macrolide-lincosamide-streptogramin B (CMLSB) phenotype, and 16.1% displayed the inducible MLSB (IMLSB) phenotype, as determined by the D-test. Different virulence factors were tested in our pathogenic strains. Biofilm formation was assessed in microtiter plates using crystal violet dye, while hemolysin, protease, lecithinase, and lipase enzyme production were determined using plates containing human blood, skimmed milk, and egg yolk, respectively. Overall, 88.1% of strains were biofilm producers, with the majority (64.9%) exhibiting a weak ability to produce biofilms. XDR strains exhibited the highest percentage of strong biofilm producers (47.6%). Hemolysin production was found in 55.5% of strains, followed by protease production 47.3% and lecithinase and lipase activities (23.1% and 10%). A phenotypic search for the production of extended-spectrum β-lactamases and AmpC was conducted, 32.6% presented ESBL phenotype and 12.7% were positive AmpC,furthermore, molecular characterization of β-lactamase genes and quinolone genes with Multiplex PCR was used for phenotypic confirmation. blaTEM was the emergence ESBL-type gene (53.8%), followed by blaSHV (15.9%), while blaCMY II was the most frequent AmpC detected gene (10.4%) followed by blaDHA (7.1%). All these genes and other virulence genes were carried by plasmids with size ranged from approximately 1.5 to ˃10 kb profiling by PCR method. 26.7% of E. coli strains harbored at least one qnr gene. The most frequent was qnrB (78.3%), followed by qnrD (26.1%). Clermont et al. PCR was used for the detection of phylogenetic groups of urinary imipenem-resistant E. coli. Of 86 clinical imipenem resistant E.coli isolates, the B2 group (48.9%) was the most prevalent phylogroup, followed by groups E (22.1%), unknown (12.8%), A (8.1%), and B1 (4.7%), and Clade I, D, Clade I, or Clade II (1.2%).

2025-10-29T00:00:00Z