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Öğe Effects of the apricot diets containing sulfur dioxide at different concentrations on rat testicles(Springer Heidelberg, 2023) Yildiz, Azibe; Ozhan, Onural; Ulu, Ahmet; Dogan, Tugba; Bakar, Busra; Ugur, Yilmaz; Taslidere, ElifDue to its antioxidant and antimicrobial properties, sulfur dioxide (SO2) is widely used in foods and beverages to prevent the growth of microorganisms and to preserve the color and flavor of fruits. However, the amount of SO2 used in fruit preservation should be limited due to its possible adverse effects on human health. The present study was designed to investigate the effects of different SO2 concentrations in apricot diets on rat testes. Animals were randomly divided into six groups. The control group was fed a standard diet, and the other groups were fed apricot diet pellets prepared with (w/w) 10% dried apricots containing SO2 at different concentrations (1500 ppm, 2000 ppm, 2500 ppm, 3000 ppm, and 3500 ppm/kg) for 24 weeks. After sacrification, testicles were evaluated biochemically, histopathologically, and immunohistopathologically. Our results showed that an apricot diet containing 1500 ppm and 2000 ppm SO2 did not cause significant changes in testis. However, it was determined that tissue testosterone levels decreased as the amount of SO2 (2500 ppm and above) increased. Apricot diet containing 3500 ppm SO2 caused a significant increase in spermatogenic cell apoptosis, oxidative damage, and histopathological changes. In addition, a decrease in the expression of connexin-43, vimentin, and 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) was observed in the same group. In summary, the results show that sulfurization of apricot at high concentrations such as 3500 ppm may lead to male fertility problems in the long term through mechanisms such as oxidative stress, spermatogenic cell apoptosis, and inhibition of steroidogenesis.Öğe Electrospun Polycaprolactone-Chitosan Nanofiber Scaffolds for Covalent Immobilization of Xylanase: Structural Characterization and Enzyme Performance(Springer, 2026) Dogan, TugbaXylanases (XyL) are critical enzymes that release that hydrolyze xylan, a major component of hemicellulose, into xylose and its derivates, and they are vital in diverse industrial fields. However, their use in free form is limited due to instability and lack of reusability. Enzyme immobilization offers a promising approach to overcome these drawbacks. In this study, electrospun polycaprolactone/chitosan (PCL/CHI) nanofibers were fabricated and used as by nanocarriers for covalent immobilization of XyL. A solution containing 10% PCL and 0.5% CHI in acetic acid: formic acid (6:4) was electrospun under optimized conditions (22 kV, 1 mL/h, 18 cm). Fibers were cross-linked with glutaraldehyde, washed thoroughly to remove residual toxicity, and then used for enzyme immobilization. Structural and morphological analyses (SEM, EDX, XRD, and FTIR) confirmed successful fiber formation and enzym binding. The optimum temperature was determined as 50 degrees C for both forms, while the optimum pH was determined as 6 for the free form and 5 for the immobilized form. The activation energy decreased from 21.46 kJ/mol to 1.17 kJ/mol, indicating enhaced catalytic efficiency. Kinetic analysis revealed a reduction in Km (13.01\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\:\to\:$$\end{document} 4.80 mg/mL), suggesting improved substrate affinity. Furthermore, the decrease in Km value revealed that immobilization enhanced enzyme-substrate interaction, while reusability tests showed that the immobilized enzyme retained 45% of its initial activity after five cycles. The fact that the immobilized form maintained its high catalytic performance in the presence of metal ions highlights the system's potential for adaptation to industrial conditions. In conclusion, this developed platform has been demonstrated to be a promising approach for sustainable and economical solutions in enzyme technologies.Öğe Polymer-based anti-adhesive barriers: A comprehensive overview of current approaches for medical and biological applications(Elsevier Sci Ltd, 2025) Dik, Gamze; Dogan, Tugba; Gedik, Kubra Karadas; Ulu, Ahmet; Ates, BurhanTissue and cell adhesions are undesirable conditions observed after surgical operations. This adhesion is seen at a high rate in many patients after the surgical operation. It is especially observed in biological parts such as the abdominal cavity, thoracic cavity, and tendons. Due to the healing of the fibrous tissues in the wound after the surgery, this part causes adhesion in the surrounding tissues and organs, and patients may develop complications such as chronic pain, intestinal obstruction and functional obstruction of organs after adhesion, may require a repeat surgical operation, and is a serious problem that may cause infertility in women. Chronic pain, intestinal obstruction, and functional obstruction of organs may develop complications after adhesion. To prevent this situation, it is very important to develop barriers with higher biocompatibility, low cost, easily applicable, and synthesizable instead of existing anti-adhesive barriers. Potential candidates with these properties are thought to be polymers. Polymers offer many options for use as anti-adhesive barriers since they can be obtained from natural sources and synthetically. These options can be designed according to the characteristics of the anti-adhesive barriers desired to be synthesized. These polymers can be produced in a short time using very simple techniques in the forms of hydrogel, membrane, fiber, film, etc. In addition to these, these polymers synthesized as anti-adhesive membranes can act as simultaneous drug release and imaging agents in various combinations. In this article, medical and biological applications of anti-adhesive barriers with various formulations developed with different polymer types are mentioned. Therefore, through this article, we report on recent work and some key points in the development of such applications.Öğe Protective effect of Lycium barbarum on renal injury induced by acute pancreatitis in rats(Wolters Kluwer Medknow Publications, 2022) Dogan, Tugba; Batcioglu, Kadir; Kustepe, Elif Kayhan; Uyumlu, Ayse Burcin; Yilmaztekin, YakupBackground: Lycium barbarum (LB) is a plant species that is well known in Chinese traditional medicine and is also considered a nutrient, belonging to the Solanaceae family, also called goji berry or wolfberry. Objectives: The aim of this study was to investigate the protective efficacy of LB, in kidney damage caused by acute pancreatitis (AP). Materials and Methods: In the study, we used 36 female Wistar albino rats (12 in each group) which were divided into three groups: Control, cerulein (100 mu g/kg b. wt. intraperitonally) and Cerulein + LB (6 mg/ml/day gastric gavage) group. Serum lipase, Interleukin (IL)-1, and IL-6 levels were measured. Superoxide dismutase, catalase (CAT), glutathione peroxidase enzyme activity assays and 8-hydroxy deoxyguanosine, malondialdehyde (MDA), and protein levels were measured in kidney tissue samples. In addition, histopathological analysis was performed in kidney tissue samples. Results: According to the findings, in the AP model created with Cerulein, administration of LB plant extract decreased oxidative stress and damage caused by AP in the kidney tissue and partially suppressed the inflammatory reactions in the tissue. Conclusion: According to the findings, in the AP model created with Cerulein, administration of LB extract decreased oxidative stress and in kidney damage caused by AP.Öğe Temporal shifts in phenolic composition and antioxidant responses of two Turkish grape cultivars ('Kureyş' and 'Tahannebi') during berry development(Springer, 2025) Ates, Sevim; Ugur, Yilmaz; Zengin, Rukiye; Demir, Nurullah; Dogan, Tugba; Erdogan, Selim; Hatterman-Valenti, HarlenePhenolic compounds play a vital role in grape quality, antioxidant potential, and stress resilience; therefore, tracking their variation across developmental stages is essential for both viticultural practices and functional food production. The aim was to characterize variety-specific phenolic dynamics and antioxidant activity changes to guide optimized harvest timing and functional quality improvement. In this regard, present study evaluated the accumulation patterns of phenolic compounds and antioxidant activity across berry developmental stages from EL-27 (Eichhorn-Lorenz phenological scale) to EL-41 in two grape (Vitis vinifera L.) cultivars, 'Kurey & scedil;' and 'Tahannebi'. A total of 17 phenolic compounds were quantified by high-performance liquid chromatography (HPLC-DAD), and total phenolic content (TPC) and antioxidant activity were determined by Folin-Ciocalteu, ABTS (2,2 '-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), and DPPH ((1,1-diphenyl-2-picrylhydrazyl) assays. Significant differences (p < 0.001) were observed between varieties, phenological stages, and their interactions for all analyzed compounds. In general, phenolic concentrations peaked during the early stages (EL-27: K1, T1) and declined progressively through EL-31 (K2, T2), EL-33 (K3, T3), EL-35 (K4, T4), EL-36 (K5, T5), EL-38 (K6, T6), and EL-41 (K7, T7). 'Kurey & scedil;' consistently exhibited higher levels of gallic acid, catechin, chlorogenic acid, and caftaric acid, with chlorogenic acid decreasing by 98.8% from EL-27 to EL-41. In contrast, 'Tahannebi' showed lower initial concentrations but retained specific compounds like ellagic acid and p-coumaric acid longer. Multivariate analyses revealed distinct metabolic clustering. PCA explained 85% of total variance, with early-stage samples characterized by enriched antioxidant profiles. Correlation analysis indicated strong associations among TPC, antioxidant capacity (ABTS, and DPPH) assays, suggesting coordinated biosynthetic regulation. Hierarchical clustering clearly distinguished early high-phenolic samples (e.g., K1, T2) from late-stage samples (K7, T7) with reduced biochemical activity. Overall, this study highlights genotype-dependent differences in phenolic composition and antioxidant capacity during grape ripening, offering integrated insights into their physiological basis and implications for harvest optimization, nutraceutical enhancement, and breeding for functional quality.
