Faculty of Natural Sciences, Life and Earth Sciences
Permanent URI for this communityhttps://dspace.univ-ghardaia.edu.dz.dz/handle/123456789/72
Browse
482 results
Search Results
Item Caractérisation physicochimique du vinaigre produit à partir de différentes variétés de dattes et évaluation in vitro de son effet antidiabétique(Université de Ghardaïa, 2026) LAIOURATE, Inas; REFFIS, SettiThis research focuses on the nutritional valorization of two Algerian common date cultivars, “Timjouhert” and “Hchef”, originating from Daïa Ben Dahoua (Ghardaïa Province, Algeria). The main objective of this study was to produce a traditional date vinegar through a simultaneous double-fermentation process under laboratory conditions, to investigate its physicochemical and biochemical characteristics, and to evaluate its in vitro antidiabetic potential in comparison with a commercial apple vinegar reference. The physicochemical analyses revealed highly significant differences (P < 0.0001) among the mples. The pH values of “Timjouhert” and “Hchef” date vinegars were 3.49 and 93.45, respectively, compared with 2.94 for apple vinegar, indicating a lower acidity of date vinegars. Electrical conductivity reached 11.91 mS/cm for “Timjouhert” and 12.71 mS/cm for “Hchef”, whereas it was only 2.76 mS/cm for apple vinegar, reflecting the high mineral content of date vinegars. Moreover, “Timjouhert” vinegar exhibited the highest total soluble solids and dry matter contents, reaching 5.00 °Brix and 4.80%, respectively, compared with 2.50 °Brix and 2.20% in apple vinegar, suggesting the presence of residual sugars resulting from incomplete fermentation. Biochemically, apple vinegar showed the highest concentrations of acetic acid (50.44 g/L) and citric acid (0.90%), while date vinegars contained 44.53 and 41.53 g/L of acetic acid, and 0.63% and 0.58% of citric acid for “Timjouhert” and “Hchef”, respectively. In contrast, protein content was higher in date vinegars, reaching 4.49% in “Hchef” and 3.77% in “Timjouhert”, compared with 2.76% in apple vinegar. Chromatographic analysis also revealed variability in the carbohydrate profiles among the different samples. Regarding the in vitro antidiabetic activity, increasing sample concentration generally enhanced α-amylase inhibitory activity. Apple vinegar and “Timjouhert” date vinegar exhibited the 8highest inhibition rates, reaching nearly 100% at concentrations between 0.75% and 1%. In contrast, “Hchef” vinegar showed a more moderate inhibitory effect, ranging from approximately 49% to 60%. Acarbose, used as the positive control, displayed intermediate inhibition rates ranging from 69% to 81%. These findings demonstrate the remarkable α-amylase inhibitory potential of “Timjouhert” date vinegar, which surpassed that of the reference drug under the experimental conditions. Overall, the results highlight the functional and therapeutic potential of date vinegars as functional foods that may contribute to postprandial glycemic regulation, reduce agricultural waste, and support the development of promising natural alternatives for diabetes prevention.Item UTILISATION DES PRODUITS PHYTOSANITAIRES DANS LA REGION DE GHARDAIA(Université de Ghardaïa, 2026) BOUNADJI, Fadila; OULAD YAHIA, ImaneThis study investigates the phytosanitary products used in the Ghardaïa region, an area characterized by intensive agricultural activity. The main objective is to evaluate the degradation kinetics of pesticides in soil as a function of time and temperature. The methodology adopted is based on a mixed approach combining data collection from the Directorate of Agricultural Services (DSA) and the Directorate of Environment to identify the phytosanitary products commonly used in the study area, followed by an experimental investigation of the degradation kinetics of two major pesticides, namely malathion and linuron, in agricultural soil collected from the Ghardaïa region. The experiment was conducted under two exposure conditions: direct solar radiation and shaded conditions. The results revealed significant differences in the degradation behavior of the two pesticides. Malathion exhibited a faster degradation rate under direct solar radiation, with an average residual concentration of 13,68% compared with 15.98 %under shaded conditions. In contrast, linuron showed average residual concentrations of 72,72% under direct solar radiation and 39,74% under shaded conditions, highlighting the influence of the chemical properties of each pesticide on its persistence in soil. These findings contribute to a better understanding of pesticide fate in agricultural soils and provide a scientific basis for optimizing pesticide management practices while reducing the risk of environmental contamination.Item De la ferme à la table : étude des caractéristiques physico- chimiques et microbiologiques d’un fromage artisanal à identité locale ''El Gafs"(UNIVERSITE DE GHARDAIA, 2026) LAHRECHE, KHOULOUD; MOSBAH, FATIMA ZOHRATraditional cheese has become a staple food due to its high nutritional value and unique sensory characteristics. El Gafs cheese, made from raw milk (cow and goat raw milk) and coated with chamomile, rose and esparto grass, has never been the subject of previous studies. Hence the aim of this study is to evaluate both its physicochemical such as pH (pH meter), acidity (titration), dry matter (drying), lipids (Gerber acid-butyrometric method), minerals (calcination) and proteins (Kjeldahl method), microbiological quality (total mesophilic aerobic flora, lactic acid bacteria, lactococci, coliforms, yeasts and moulds, as well as testing for pathogenic bacteria) and sensory parameters (appearance, colour, odour, texture, firmness, taste, lactic flavour and overall acceptability through tasting). The results showed differences between the four cheese varieties in most of the criteria studied; Physicochemical analyses revealed significant differences among the El Gafs cheese varieties, with variations in pH (3.8–5.9), acidity (8–16 °D), dry matter (≈50–61%), proteins (18–39%), lipids (6–14%), and minerals (≈3–4%), influenced by the type of milk and the plant coating. The microbiological criteria revealed the presence of abundant lactic flora, which is characteristic of traditional cheeses made from raw milk, and they also showed the absence of Staphylococcus aureus, Salmonella spp., sulfite-reducing anaerobic bacteria (SRB) and Listeria monocytogenes. Sensory evaluation also revealed greater overall acceptance of the cow’s milk cheese coated with chamomile. The results suggest that the type of milk and the nature of the plant coating influence the characteristics of the cheeses studied. These findings contribute to a better understanding of the nutritional and sanitary quality of this traditional product.Item Etat des lieux et diversité scorpionique (Scorpiones, Arachnida) de la région de Ghardaïa (Centre de l’Algérie)(Université de Ghardaïa, 2026) Souilem, ZinebScorpions are among the oldest and most highly adapted arthropods to extreme desert environments; their remarkable ecological plasticity having enabled them to persist for more than 450 million years across all major geological eras. The present study focuses on the inventory and ecological analysis of scorpion assemblages in the region of Ghardaïa (central Algerian Sahara), with the primary objective of assessing the influence of habitat type on scorpion diversity and spatial distribution in arid ecosystems. Sampling was conducted over a 12-month period across four contrasting biotopes (erg, reg, palm grove and urban area) using two complementary methods: direct capture and nocturnal detection with ultraviolet lamps. A total of 305 individuals were collected, representing 11 species belonging to the family Buthidae, distributed across 6 genera. The results reveal a strong numerical dominance of Androctonus amoreuxi (58%) and A. australis (24.4%), together accounting for more than 82% of total individuals. PERMANOVA analyses confirm that habitat type is the primary factor structuring scorpion assemblages, while season exerts a secondary yet statistically significant effect. The palm grove exhibited the highest abundance, whereas the reg and erg displayed the greatest species richness and diversity, harboring specialized species adapted to rocky and sandy microhabitats, respectively. The urban area proved to be the most depauperate biotope, with only a single species recorded, reflecting severe environmental filtering induced by increasing habitat artificialization. NMDS ordination revealed a strong ecological affinity between most species and their respective biotopes, with the notable exception of A. amoreuxi, whose broad ecological valence allows it to colonize three distinct habitats: the reg, erg and palm grove.Item Recherche des Actinomycetota contribuant à la biosynthèse des nanoparticules d’argent pour des applications antimicrobiennes(Université de Ghardaia, 2026) ABBAS, MARIA; TEBBAKH, BOUCHRAThe main objective of this work is to investigate Actinomycetota involved in the biosynthesis of silver nanoparticles (AgNPs) intended for antimicrobial applications. For this purpose, ten Actinomycetota isolates (L1, L2, L3, L4, L5, L6, L7, L8, L9, and L10) were cultured in ISP2 medium. The biosynthesis of AgNPs was carried out using silver nitrate (AgNO3) as a metallic precursor and the Actinomycetota biomass extract as a reducing and stabilizing agent. The obtained nanoparticles were subsequently purified and dried. To optimize their synthesis, several parameters were studied, including AgNO3 concentration, pH, and temperature. The bioreduction of Ag + ions to Ag 0 was evidenced by the color change of the solution to dark brown, observed for strains L1, L3, L4, L6, L7, and L10 during extracellular synthesis, as well as for strains L1 and L4 during intracellular synthesis. This synthesis was also confirmed by UV-Visible spectrophotometric analysis, which revealed characteristic absorption peaks of silver nanoparticles at 340, 355, 365, 390, 400, 425, 440, and 455 nm. Furthermore, the antimicrobial activity of the synthesized AgNPs was evaluated against various pathogenic microorganisms using the agar well diffusion method. For this study, three strains presenting the most characteristic UV-Visible absorption profiles associated with high AgNP production (L3, L6, and L10) were selected. The results showed strong antimicrobial activity against Candida albicans, followed by moderate activity against Staphylococcus aureus and Aspergillus flavus, as well as weak activity against Pseudomonas aeruginosa. Comparative analysis of the different strains revealed significant variability in their antimicrobial efficacy. Strain L3 stood out with the broadest spectrum of action, inhibiting the growth of all tested microorganisms. It recorded the largest zones of inhibition against Candida albicans (20.67 mm), followed by Aspergillus flavus (13.33 mm), Staphylococcus aureus (12 mm), and Pseudomonas aeruginosa (11.33 mm). Strain L10 presented a more selective activity, limited against Candida albicans (19.83 mm) and against the Gram-positive bacterium Staphylococcus aureus (9.33 mm), without any effect on Pseudomonas aeruginosa or Aspergillus flavus. As for strain L6, it presented the lowest activity, acting only on Candida albicans with an inhibition zone of 17.33 mm, while remaining inactive against the other tested microorganisms.Item Étude comparative du genre Kineosporia fondée sur des approches moléculaires et chimiotaxonomiques utilisant les coefficients de Jaccard et d’Ochiai(Université de Ghardaïa, 2026) BEHISSA, Dounia; BELKACEM, MeriemThis research is based on a two-pronged methodological approach aimed at studying eight species of the genus Kineosporia (phylum Actinomycetota): K. aurantiaca, K. succinea, K. rhizophila, K. mikuniensis, K. rhammosa, K. babensis, K. mesophila, and K. corallincola. On the one hand, a chemotaxonomic analysis was conducted by applying Jaccard and Ochiai similarity coefficients to the chemical composition data of the cell walls. On the other hand, a molecular study was conducted based on 16S rRNA gene sequencing, coupled with bioinformatics algorithms for sequence alignment and genetic distance estimation. The main objective was to identify the most closely related species to Kineosporia corallincola (used as a reference) and to compare the results obtained by these two methods. The results revealed a partial divergence: the chemotaxonomic approach identifies K. aurantiaca as the species closest to K. corallincola, while the molecular analysis identifies K. babensis as the most closely related. This study thus highlights the complementary nature of chemotaxonomic and molecular approaches for reliable taxonomic classification.Item Analyse in silico d’allantoinase d’Actinopolyspora saharensis(Faculté des Sciences de la Nature et de la Vie et des Sciences de la Terre, Université de Ghardaia, 2026) LALI, Yousra; YAGOUB, AsmaAllantoinase (EC 3.5.2.5) is an enzyme belonging to the amidohydrolase family. It is involved in the purine catabolism by hydrolyzing the amide bond between N3 and C4 of allantoin, converting it into allantoate. This reaction constitutes a key step in the biosynthesis and degradation of purines as well as nitrogen recycling in many organisms, including bacteria, fungi, and plants. However, this enzyme is absent in humans, in whom purine metabolism terminates at the formation of uric acid. However, allantoinase remains poorly characterized, particularly in Actinopolyspora saharensis. This study therefore aimed to determine its physicochemical properties, subcellular localization, and 3D structure using bioinformatics approaches. These analyses revealed the acidic nature, stability, and hydrophilicity of this enzyme, as well as its cytoplasmic localization. Secondary structure prediction, performed using the SOPMA tool, revealed a predominance of loops (50.33%), followed by α-helices (27.79%) and β-sheets (21.88%). The AlphaFold tool generated the most reliable 3D structure model compared to other tools, including SWISS-Model, Phyre2, I-TASSER, and trRosetta. This protein model was validated using PROCHECK, ERRAT, and Verify 3D. Analysis of protein–protein interactions identified aspartate carbamoyltransferase as a major partner (confidence score: 0.999). Functional analysis using CD Search identified L-hydantoinase and allantoinase as conserved domains (E-value equal to 0). To assess the biotechnological potential of this enzyme, molecular docking was performed. Interesting results were obtained regarding the degradation of herbicides, with the best result observed for Nicosulfuron, which exhibited a binding energy of -8.2 kcal/mol, highlighting its potential for bioremediation applications. However, these findings are computational and require experimental validation.Item Etude phytochimique et évaluation des activités antioxydante et antibactérienne des extraits de Orobanche aegyptiaca Pers.(Faculté des Sciences de la Nature et de Vie et Sciences de la Terre, Université de Ghardaia, 2026) KIOUAS, Zineb; MOUSSA, SabrinaOrobanche aegyptiaca Pers. is a medicinal holoparasitic plant belonging to the Orobanchaceae family, commonly known by the vernacular name “El-Danone” and widely used in traditional medicine. The aim of this work is to carry out a phytochemical study and to evaluate the antioxidant and antibacterial activities of the plant extracts. The extraction of bioactive compounds from the aerial parts of the plant was performed using Soxhlet extraction with two solvents of different polarities: methanol and hexane yielding 21.04% and 1.56% for the methanolic and hexanic extracts, respectively. Quantitative analysis of total polyphenols, carried out using the Folin–Ciocalteu method, and flavonoids, determined by the aluminum chloride (AlCl₃) method, showed that the methanolic extract was the richest in phenolic compounds, with contents of 169.81 ± 3.18 µg GAE/mg extract for polyphenols and 11.64 ± 0.86 µg QE/mg extract for flavonoids. The in vitro antioxidant activity of the extracts was evaluated using four methods: total antioxidant capacity (TAC), DPPH and ABTS radical scavenging assays, and reducing power assay. The results demonstrated that the methanolic extract possessed a good antioxidant capacity (TAC = 197.81 ± 2.04 µg AAE/mg extract). In addition, this extract exhibited significant free radical scavenging activity against DPPH and ABTS radicals, with IC₅₀ values of 36.77 ± 0.96 µg/mL and 30.07 ± 2.10 µg/mL, respectively. It also showed a good reducing power with an A 0,5 value of 220.55 ± 3.03 µg/mL. The antibacterial activity was evaluated using the microdilution method in liquid medium on microplates. The obtained results showed that the methanolic extract exhibited greater antibacterial activity than the hexanic extract. The most sensitive bacterial strain was Escherichia coli, with MIC and MBC values of 31.25 mg/mL and 62.5 mg/mL, respectively. In conclusion, these results support the traditional use of this plant and open up prospects for future therapeutic applications.Item Étude in silico de la fluoroacétate déhalogénase d’Actinoalloteichus hoggarensis(Faculté des Sciences de la Nature et de la Vie et les Sciences de la Terre, Université de Ghardaïa, 2026) ABAYAHIA, Ikrame; ZERGOUN, SaraPer- and polyfluoroalkyl substances (PFAS) are persistent and widespread fluorinated organic pollutants that require the development of advanced remediation methods. The fluoroacetate dehalogenase from Actinoalloteichus hoggarensis is a promising microbial enzyme for the defluorination of these compounds. It is involved in the dehalogenation of fluoroacetate by breaking the strong carbon–fluorine (C–F) covalent bond via an SN2-type reaction mechanism, leading to the formation of glycolate. This enzyme was the subject of an in silico study aimed at characterizing its structural and functional properties. Analysis of the physicochemical properties of the protein sequence indicates that it is an acidic, thermostable, and hydrophobic protein. Furthermore, subcellular localization analysis suggests a cytoplasmic protein. The prediction of the secondary structure, performed using the SOPMA and PSIPRED tools, reveals a predominance of α-helices over β-sheets, with an estimated proportion of 43.49%. The three-dimensional structure of the enzyme, predicted by homology modeling using the SWISS-MODEL server, exhibits the highest structural quality compared to other servers. It was subsequently validated using the PROCHECK, ERRAT, and Verify3D tools. Furthermore, analysis performed with MOTIF Finder identified three domains characteristic of the α/β hydrolase superfamily. Molecular docking also allowed us to estimate the interaction energy with perfluorooctanesulfonic acid (PFOS) at −7.2 kcal/mol (Vina score), thereby predicting the enzyme’s potential to interact with the selected ligands. These results provide an important theoretical basis for elucidating the reaction mechanism of fluoroacetate dehalogenase as well as for engineering improved enzyme variants.Item In silico study of the anti-amylase activity of certain metabolites derived from marine organisms(Faculty of Natural Sciences, Life and Earth Sciences, University of Ghardaia, 2026) TFYECHE , Yousra; TIRICHINE, SanaDiabetes mellitus is a prevalent chronic metabolic disorder characterized by persistent hyperglycemia resulting from impaired insulin secretion or reduced insulin activity in target tissues, which prevents the efficient utilization and storage of glucose. Although several antidiabetic medications are currently available, their adverse effects continue to limit therapeutic effectiveness. In this context, inhibition of human pancreatic α-amylase (HPA), a key enzyme involved in carbohydrate digestion, represents an important therapeutic strategy for the management of Type 2 Diabetes Mellitus (T2DM). The present study adopted a stepwise in silico strategy aimed at identifying safe and potent HPA inhibitors from marine-derived secondary metabolites. Initially, an extensive literature survey was conducted to collect compounds previously extracted, purified, and chemically characterized from marine organisms. The selected molecules were then subjected to safety filtering based on cardiotoxicity and carcinogenicity predictions in order to retain only safe compounds. Subsequently, the remaining safe candidates were evaluated through molecular docking against HPA using AutoDock Vina, while interaction analysis and visualization were performed with Discovery Studio Visualizer. The results revealed that several marine metabolites display strong binding affinity toward the catalytic site of HPA and exhibit favorable pharmacokinetic and safety profiles. Among them, Mol7, Mol22, and Mol23, derived from Aspergillus and Streptomyces species, demonstrated the highest inhibitory potential with binding energies of - 10.0 kcal/mol and -9.5 kcal/mol, respectively. Importantly, all selected compounds showed stronger binding affinities than the reference inhibitor acarbose (-7.9 kcal/mol). These findings highlight the potential of marine-derived secondary metabolites as promising candidates for the development of novel HPA inhibitors for the treatment of T2DM. Nevertheless, further in vitro and in vivo studies are required to validate these computational predictions.