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    Immune activation by Ziziphus jujuba in Galleria mellonella: challenge-specific and temporal dynamics of humoral immune responses
    (Cambridge Univ Press, 2026) Genc, Tulay Turgut; Kaya, Serhat; Gunay, Melih
    The immunomodulatory effects of Ziziphus jujuba Mill. fruit extracts were investigated using Galleria mellonella as an insect immune model. The expression of antimicrobial peptides, hemolin, phenoloxidase genes (PO-I and PO-II), and enzyme activity was measured in response to Candida albicans, silica beads, and Z. jujuba fruit extract. Responses were found to be stimulus- and time-dependent. Gallerimycin and galiomycin, key antimicrobial peptides, exhibited distinct expression patterns, with gallerimycin showing a more pronounced response to pathogens and beads. The Z. jujuba extract stimulated an early but balanced immune activation, likely due to its bioactive compounds. Hemolin expression varied between larvae and haemocytes depending on the type and duration of the challenge, supporting its role in immune recognition and opsonisation. Phenoloxidase activity and gene expression were also enhanced, supporting their role in promoting melanisation processes. Docking analyses suggested that hemolin contributes to phenoloxidase activation by stabilising PO-I and interacting with the phenoloxidase-activating factor-1-like protein (PAP1). The findings suggest that Z. jujuba extract effectively modulates immune responses, promoting enhanced protection while maintaining immune balance. GC-MS analysis revealed multiple bioactive compounds potentially contributing to immune modulation. This study highlights the significant immunomodulatory effects of Z. jujuba fruit extract on the immune system of G. mellonella. The findings suggest its potential as a natural immunostimulant and warrant further investigation of the underlying molecular mechanisms and bioactive components.
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    Internal transcribed spacer (ITS) sequence-based identification of yeast biota on pomegranate surface and determination of extracellular enzyme profile
    (Univ Sebelas Maret, 2020) Genc, Tulay Turgut; Gunay, Melih
    Yeasts are the most significant organisms to produce fermented products from different types of fruits such as grape, strawberry and pomegranate. The native yeasts on these fruits contribute to beverages' quality and aroma during fermentation. Pomegranate is used in fruit juice and wine production because of high antioxidant characteristic. In order to determine yeast microbiota on the pomegranate fruits collected from Gallipoli (Gelibolu), Canakkale-Turkey, ITS-5.8S rDNA gene region have been utilized. Also, phylogenetic relationships among identified yeast species were assigned by using sequences of ITS-5.8S rDNA gene region. In addition, extracellular enzyme activity of identified yeast strains was detected by using API-ZYM. Kluyveromyces lactis, Aureobasidium pullulans, Hanseniaspora uvarum, Candida zeylanoides, Kwoniella sp., and Metschnikowia pulcherrima and Metschnikowia ziziphicola yeast species were identified on pomegranate surface. Phylogenetic analysis, carried out in ITS-5.8S rDNA gene region of identified yeast strains, revealed the presence of five clades. Kwoniella sp., H. uvarum, M. pulcherrima, and Kl. lactis yeast strains revealed high leucine arylamidase activity. Also valine arylamidase activity was determined in M. pulcherrima and Kl. lactis yeast species. Acid phosphatase activity was determined in H. uvarum and K. lactis yeast species. Uncultured Kwoniella sp. and H. uvarum yeast species displayed high beta-galactosidase and beta-glucosidase activities, respectively.