Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 11Fabrication of Helix Aspersa Extract Loaded Gradient Scaffold With an Integrated Architecture for Osteochondral Tissue Regeneration: Morphology, Structure, and in Vitro Bioactivity [2](American Chemical Society, 2023) Tamburacı, Sedef; Perpelek, Merve; Aydemir, Selma; Baykara, Başak; Havıtçıoğlu, Hasan; Tıhmınlıoğlu, FundaRegeneration of osteochondral tissue with its layered complex structure and limited self-repair capacity has come into prominence as an application area for biomaterial design. Thus, literature studies have aimed to design multilayered scaffolds using natural polymers to mimic its unique structure. In this study, fabricated scaffolds are composed of transition layers both chemically and morphologically to mimic the gradient structure of osteochondral tissue. The aim of this study is to produce gradient chitosan (CHI) scaffolds with bioactive snail (Helix aspersa) mucus (M) and slime (S) extract and investigate the structures regarding their physicochemical, mechanical, and morphological characteristics as well as in vitro cytocompatibility and bioactivity. Gradient scaffolds (CHI-M and CHI-S) were fabricated via a layer-by-layer freezing and lyophilization technique. Highly porous and continuous 3D structures were obtained and observed with SEM analysis. In addition, scaffolds were physically characterized with water uptake test, micro-CT, mechanical analysis (compression tests), and XRD analysis. In vitro bioactivity of scaffolds was investigated by co-culturing Saos-2 and SW1353 cells on each compartment of gradient scaffolds. Osteogenic activity of Saos-2 cells on extract loaded gradient scaffolds was investigated in terms of ALP secretion, osteocalcin (OC) production, and biomineralization. Chondrogenic bioactivity of SW1353 cells was investigated regarding COMP and GAG production and observed with Alcian Blue staining. Both mucus and slime incorporation in the chitosan matrix increased the osteogenic differentiation of Saos-2 and SW1353 cells in comparison to the pristine matrix. In addition, histological and immunohistological staining was performed to investigate ECM formation on gradient scaffolds. Both characterization and in vitro bioactivity results indicated that CHI-M and CHI-S scaffolds show potential for osteochondral tissue regeneration, mimicking the structure as well as enhancing physical characteristics and bioactivity. © 2023 The Authors. Published by American Chemical Society.Article Citation - WoS: 5Citation - Scopus: 5Screening of Cytotoxicity and Dna Topoisomerase Iia Inhibitory Activity of Turkish Onosma Species(TÜBİTAK, 2021) Güzel, Özge; Duman, Seda; Yılmaz, Sinem; Karakoyun, Çiğdem; Kul, Demet; Pirhan, Ademi Fahri; Bedir, ErdalOnosma L., the largest genus of Boraginaceae, is represented by 105 species in Turkey with an endemism rate of 52%. Phytochemical studies indicate that Boraginaceae plants mainly comprise naphthoquinones with a wide range of biological activities including anticancer, antiinflammatory, wound healing, and antioxidant effects. However, few taxa of the genus Onosma have been investigated in detail for their bioactivities. Considering the high rate of endemism and an inadequate number of bioactivity screening studies in literature, we aimed to evaluate the cytotoxic effects and topoisomerase inhibitory activities of some Onosma species growing in southwestern Turkey. Here, we describe a comprehensive cytotoxic activity screening study on petroleum ether, dichloromethane, and methanol extracts of the roots of 20 identified and one unidentified Onosma taxa. The MTT cell viability assay has been performed to investigate the cytotoxicity of the extracts against seven cancer cell lines (MCF-7, HeLa > Hep G2, A549, Capan-1, HCC-1937, and DU-145) and a noncancerous cell line (MRC-5), while doxorubicin was served as a positive standard. The petroleum ether extracts of O. aksoyii Aytac&Turkmen, O. isaurica Boiss. and Heldr., O. taurica Pallas ex Willd. var. taurica and O. alborosea Fisch. & C.A. Mey subsp. alborosea var. alborosea were determined as the most active ones based on their IC50 values. DNA topoisomerase Ila inhibition assay was conducted on the petroleum ether and dichloromethane extracts of these four active species, and almost all tested extracts demonstrated strong inhibition on the enzyme at a concentration of 0.1 mg/mL. Our cytotoxicity screening results were consistent with the findings of the topoisomerase Ila inhibition test. This study advocates the significant role of Onosma species in the field of anticancer drug discovery.Article Citation - WoS: 4Citation - Scopus: 5Adsorption/Desorption and Biofunctional Properties of Oleuropein Loaded on Different Types of Silk Fibroin Matrices(The Society of Chemists and Techonogists of Macedonia, 2017) Bayraktar, Oğuz; Balta, Ali Bora; Başal Bayraktar, GüldemetThe objective of this study was to investigate the adsorption/desorption behavior of oleuropein on different types of silk fibroin matrices including silk fibroin microfibers (MF), regenerated silk fibroin (RSF), and silk fibroin nanofibers (NF). Nanofibers with an average diameter of ranging between 24 and 326 nm were successfully prepared using the electrospinning technique. The effects of the silk fibroin concentration, the voltage applied and the distance between needle tip and collector plate on the morphol-ogy of the NF were investigated. The adsorption capacities of MF, RSF and NF were determined as 104.92, 163.07 and 228.34 mg oleuropein per gram of material, respectively. The percentage of initially adsorbed oleuropein that was desorbed was 86.08, 91.29 and 96.67% for MF, RSF and NF, respectively. NF and RSF discs loaded with oleuropein were subjected to disc diffusion assays to determine their antibacterial activity against test microorganisms Staphylococcus epidermidis (Gram +) and Esche-richia coli (Gram -). The results showed that both biomaterials possessed antibacterial properties after loading with oleuropein. Wound scratch assays using oleuropein released from NF revealed an enhance-ment of cell migration, indicating a wound healing property of the material. In conclusion, the NF can be utilized as a biofunctional polymeric material with better perfor-mance for the adsorption and desorption of oleuropein compared with MF and RSF.Article Citation - WoS: 12Citation - Scopus: 14Identification and Bioactivity of Native Strains of Bacillus Thuringiensis From Grain-Related Habitats in Turkey(Elsevier Ltd., 2008) Apaydın, Özgür; Çınar, Çelenk; Turanlı, Ferit; Harsa, Hayriye Şebnem; Güneş, HaticeA native collection of Bacillus thuringiensis (Bt) strains originated from grain-related habitats in Turkey was characterized according to serotype, cry1 gene content, and bioactivity against Ephestia kuehniella (Lepidoptera: Phycitidae) and Spodoptera littoralis (Lepidoptera: Noctuidae). Twenty-three different serotypes as well as 24 unknown serotypes were obtained from 56 positively agglutinated strains with previously characterized antisera. Most common serovars were sotto, kim, and tochigiensis with the percentages of 14, 14, and 13, respectively. Among the cry1 gene-positive 36 strains, cry1E (100%), cry1Aa (94%), cry1Ac (92%), and cry1D (83%) genes were the most abundant. Bioactivity tests with 56 Bt strains carrying cry1, cry2, and/or cry9 genes indicated that all of them resulted in growth retardation or inhibition of larvae of both E. kuehniella and S. littoralis; however, only one strain, 85PPb (serovar morrisoni), caused high mortality in both insects (84% and 100%, respectively). Different crystal morphology was observed for the strain 85PPb and the standard strain B. thuringiensis subsp. morrisoni. Finally, no correlation was found among serotype, cry gene content and biotoxicity of Bt strains in the collection.