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Öğe Characterization of the antioxidant activity, total phenolic content, enzyme inhibition, and anticancer properties of Achillea millefolium L. (yarrow)(Taylor & Francis Inc, 2022) Karaaslan Ayhan, Nagihan; Karaaslan Tunc, Merve Goksin; Noma, Samir Abbas Ali; Kurucay, Ali; Ates, BurhanThe antioxidant activity, total phenolic content, enzyme inhibition, anticancer properties of Achillea millefolium L. (yarrow), which is generally consumed by humans as herbal tea, were investigated. Yarrow extracts were prepared with different extraction techniques and solvents and the optimum conditions were determined. When the antioxidant activity and total phenolic content results were evaluated, the best yield was obtained with ultrasound-assisted extraction for all solvents. Moreover, the yields from highest to lowest were methanol, water, and acetonitrile. The enzyme inhibition and anticancer of Achillea millefolium L. extracts using methanol were evaluated. The IC50 values for the inhibition of xanthine oxidase and acetylcholinesterase were 4.974 +/- 0.54 and 21.891 +/- 1.118 mu g/mL, respectively. The extract concentration was determined to be 23.85 mu g/mL for 50% reduction in growth inhibitory activity cell viability (IC50) against breast cancer (MCF-7).Öğe Chloro-Modified Magnetic Fe3O4@MCM-41 Core-Shell Nanoparticles for L-Asparaginase Immobilization with Improved Catalytic Activity, Reusability, and Storage Stability(Springer, 2019) Ulu, Ahmet; Noma, Samir Abbas Ali; Koytepe, Suleyman; Ates, BurhanThis paper describes a new support that permits to efficient immobilization of L-asparaginase (L-ASNase). For this purpose, Fe3O4 magnetic nanoparticles were synthesized and coated by MCM-41. 3-chloropropyltrimethoxysilane (CPTMS) was used as a surface modifying agent for covalent immobilization of L-ASNase on the magnetic nanoparticles. The chemical structure; thermal, morphological, and magnetic properties; chemical composition; and zeta potential value of Fe3O4@MCM-41-Cl were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), differential scanning calorimetry (DSC), vibrating sample magnetometer (VSM), scanning electron microscope (SEM), energy dispersive X-ray (EDX), X-ray diffraction patterns (XRD), and zeta-potential measurement. The immobilization efficiency onto Fe3O4@MCM-41-Cl was detected as 63%. The reusability, storage, pH, and thermal stabilities of the immobilized L-ASNase were investigated and compared to that of soluble one. The immobilized enzyme maintained 42.2% of its original activity after 18cycles of reuse. Furthermore, it was more stable towards pH and temperature compared with soluble enzyme. The Michaelis-Menten kinetic properties of immobilized L-ASNase showed a lower V-max and a similar K-m compared to soluble L-ASNase. Immobilized enzyme had around 47 and 32.5% residual activity upon storage a period of 28days at 4 and 25 degrees C, respectively. In conclusion, the Fe3O4@MCM-41-Cl@L-ASNase core-shell nanoparticles could successfully be used in industrial and medical applications.Öğe Comparative study of ASNase immobilization on tannic acid-modified magnetic Fe3O4/SBA-15 nanoparticles to enhance stability and reusability(Royal Soc Chemistry, 2020) Noma, Samir Abbas Ali; Ulu, Ahmet; Acet, Omur; Sanz, Raul; Sanz-Perez, Eloy S.; Odabasi, Mehmet; Ates, BurhanIn this work, l-asparaginase was immobilized on tannic acid-modified magnetic mesoporous particles. In brief, Fe3O4/SBA-15/tannic acid magnetic particles were synthesized, and their structures and morphologies were fully characterized using various methods. The properties of the free and immobilized enzyme were examined in terms of pH, temperature, thermal stability, storage stability, and reusability. Moreover, the effects of metal ions, inhibitors and organic solvents on the activity of the immobilized enzyme were investigated. Compared to the free enzyme, the immobilized enzyme possessed better tolerance to changes in ambient temperature and pH. Additionally, thermal incubation results showed that the free enzyme lost its activity, while the immobilized enzyme exhibited the opposite behavior. Most strikingly, the immobilized l-asparaginase exhibited a high degree of activity (70%) after being reused 16 times while also demonstrating 71% and 63% storage stability of the initial activity even after 28 days at 4 degrees C and room temperature, respectively. Together with these results, l-asparaginase was successfully immobilized upon Fe3O4/SBA-15/tannic acid magnetic nanoparticles with improved stability properties. This support holds great potential and opens up a novel perspective for growing applications.Öğe The Cytotoxicity, DNA Fragmentation, and Decreasing Velocity Induced By Chromium(III) Oxide on Rainbow Trout Spermatozoa(Springernature, 2023) Ozgur, Mustafa Erkan; Ulu, Ahmet; Gurses, Canbolat; Ozcan, Imren; Noma, Samir Abbas Ali; Koytepe, Suleyman; Ates, BurhanThe present study aimed to determine the cytotoxicity of chromium(III) oxide micro particles (Cr2O3-Ps) in rainbow trout (Oncorhynchus mykiss) spermatozoa. Firstly, Cr2O3-Ps were synthesized and structurally characterized the surface, morphological for particle size and thermal properties. In addition, its structural and elemental purity was determined using energy-dispersive X-ray (EDX) spectrum and elemental maps. Structural purity, thermal properties, and stability of Cr2O3 -Ps were also examined in detail by performing thermal analysis techniques. The cytotoxicity of Cr2O3-Ps was measured by the observation of velocities, antioxidant activities, and DNA damages in rainbow trout spermatozoa after exposure during 3 h in vitro incubation. The straight line velocity (VSL), the curvilinear velocity (VCL), and the angular path velocity (VAP) of spermatozoa decreased after exposure to Cr2O3-Ps. While the superoxide dismutase (SOD) and the catalase (CAT) decreased, the lipid peroxidation increased in a dose-dependent manner. However, the total glutathione (tGSH) was not affected in this period. DNA damages were also determined in spermatozoa using Comet assay. According to DNA in tail (%) data, DNA damages have been detected with gradually increasing concentrations of Cr2O3-Ps. Furthermore, all of class types which are categorized as the intensity of DNA fragmentation has been observed between 50 and 500 mu g/L concentrations of Cr2O3-Ps exposed to rainbow trout spermatozoa. At the end of this study, we determined that the effective concentrations (EC50) were 76.67 mu g/L for VSL and 87.77 mu g/L for VCL. Finally, these results about Cr2O3-Ps may say to be major risk concentrations over 70 mu g/L for fish reproduction in aquatic environments.Öğe Design of laccase-metal-organic framework hybrid constructs for biocatalytic removal of textile dyes(Pergamon-Elsevier Science Ltd, 2022) Birhanli, Emre; Noma, Samir Abbas Ali; Boran, Filiz; Ulu, Ahmet; Yesilada, Ozfer; Ates, BurhanThis study aims to present a simple and effective carrier matrix to immobilize laccase as opposed to complex and tedious immobilization processes and also to use it in the removal of textile dyes. For this purpose, Cobalt (Co) and Copper (Cu) based metal-organic frameworks (MOFs) were prepared and laccase was immobilized on two different MOFs via encapsulation. The characterization outcomes showed that laccase was well immobilized into MOF supports. Optimum pH and temperature were found for Lac/Co-MOF (pH 4.5 at 50 degrees C) and Lac/Cu-MOF (pH 5.0 at 50 degrees C). The Km (0.03 mM) and Vmax (97.4 mu mol/min) values of Lac/Cu-MOF were lower than those of Lac/Co-MOF (Km = 0.13 mM, Vmax = 230.7 mu mol/min). The immobilized laccases showed good reusability as well as improved resistance to temperature denaturation and high storage stability. For instance, the Lac/Co-MOF and Lac/Cu-MOF retained more than 58% activity after 4 weeks of storage at room temperature. Meanwhile, Lac/Co-MOF and Lac/Cu-MOF maintained 56.5% and 55.8% of their initial activity, respectively, after 12 reuse cycles. Moreover, thermal deactivation kinetic studies of immobilized laccases displayed lower k value, higher t1/2, and enhancement of thermodynamic parameters, which means better thermostability. Finally, the decolorization activities for the Lac/Co-MOF were 78% and 61% at the 5th cycle for Reactive Blue 171 andÖğe Design, synthesis, spectroscopic characterizations, single crystal X-ray analysis, in vitro xanthine oxidase and acetylcholinesterase inhibitory evaluation as well as in silico evaluation of selenium-based N-heterocyclic carbene compounds(Taylor & Francis Inc, 2023) Kaya, Guelsen; Noma, Samir Abbas Ali; Celepci, Duygu Barut; Bayil, Imren; Taskin-Tok, Tugba; Gok, Yetkin; Ates, BurhanHerein, eight new NHC-based selenourea derivatives were synthesized and characterized by using spectroscopic method (H-1, F-19, and C-13 NMR, FT-IR), and elemental analysis techniques. These compounds were synthesized by mixing benzimidazolium salts, potassium carbonate, and selenium powder in ethyl alcohol. Additionally, the molecular and crystal structures of the three compounds (1c, 2b, and 2c) were determined using the single-crystal x-ray diffraction (XRD) method. Diffraction analysis demonstrated the partial carbon-selenium double-bond character of these compounds. All compounds were determined to be highly potent inhibitors for AChE and XO enzymes. The IC(50 )values for the compounds were found in the range of 0.361-0.754 mu M for XO and from 0.995 to 1.746 mu M for AChE. The DNA binding properties of the compounds were investigated. These compounds did not have a remarkable DNA binding property. Also, DPPH radical scavenging activities of the compounds were also investigated. Compounds (1c), (2a), (3a), and (3b) exhibited more pronounced DPPH radical scavenging activity when compared to other compounds. Docking studies were applied by using AutoDock 4 to determine interaction mechanism of the selected compounds (1a), (1b), and (3b). The compound (1b) has good binding affinity (-9.78 kcal/mol) against AChE, and (-6.86 kcal/mol) for XO target. Drug similarity properties of these compounds compared to positive controls were estimated and evaluated by ADMET analysis. Furthermore, molecular dynamics simulations have been applied to understand the accuracy of docking studies. These findings and the defined compounds could be potential candidates for the discovery and progress of effective medicine(s) for AChE and XO in the future.In this study, we synthesized selenourea derivatives from N-heterocyclic carbene (NHC) precursors. All compounds were characterized by using NMR, FTIR spectroscopic method, and elemental analysis technique. In addition, the crystal structure of the three compounds was determined using the single-crystal X-ray diffraction method. New selenoura derivatives were tested for their effect to inhibit the xanthine oxidase and acetylcholinesterase enzymes. The DNA binding properties of the Se-NHC compounds were investigated and the compounds did not have significant DNA binding properties. In addition, DPPH radical scavenging activities of Se-NHC compounds were also investigated. All compounds exhibited DPPH radical scavenging activity. Molecular Docking studies using AutoDock 4 were used to determine the interaction mechanism of selected compounds (1a, 1b, and 3b) Drug similarity properties of these compounds compared to positive controls were estimated and evaluated by ADMET analysis. Furthermore, molecular dynamics simulations have been applied to understand the accuracy of docking studies.Öğe Development of L-asparaginase@hybrid Nanoflowers (ASNase@HNFs) Reactor System with Enhanced Enzymatic Reusability and Stability(Springer, 2021) Noma, Samir Abbas Ali; Yilmaz, Burcu Somturk; Ulu, Ahmet; Ozdemir, Nalan; Ates, BurhanHybrid nanoflowers materials have recently received great attention in enzyme immobilization applications because of the advantages such as their large surface area, excellent stability, simple, eco-friendly, and cost-effective synthesis. In this study, l-asparaginase which is an important commercial enzyme in the medicine and food industry was selected as a model enzyme. To the best of our knowledge, this study is the first report of designing L-asparaginase@hybrid nanoflowers to enhance its enzymatic performance. L-asparaginase@hybrid nanoflowers were synthesized using ASNase as an organic component and Cu(II) ion as inorganic component. They were characterized by their morphology and chemical point of view by using different techniques. The synthesized L-asparaginase@hybrid nanoflowers exhibited high residual activity at broad pH and high temperature ranges in comparison to free form. Moreover, L-asparaginase@hybrid nanoflowers possessed good reusability and excellent long-time storage stability. Especially, L-asparaginase@hybrid nanoflowers-3 maintained nearly 51 and 75% of its original activity, respectively, after nine consecutive catalytic cycles and storage at 30 degrees C for 4 weeks. The results indicated that these hybrid nanoflowers will be promising carrier matrix for the immobilization of ASNase in biotechnological applications with improved catalytic properties. [GRAPHICS] .Öğe Effects of taurine and apocynin on the zone of stasis(Elsevier Sci Ltd, 2022) Ocuk, Ozcan; Firat, Cemal; Yildiz, Azibe; Vardi, Nigar; Ulu, Ahmet; Noma, Samir Abbas Ali; Parlakpinar, HakanBackground: Among the zones of coagulation, hyperemia and stasis that occur in the burned area, the most intense metabolic process and the highest sensitivity to recovery with treatment is the zone of stasis.This metabolic process is related to how well the tissues in the zone of stasis can cope with oxidative stress. If the tissues in the zone of stasis are saved, the burn area will potentially heal faster and with less scar. In this study, we examined the effects of taurine amino acids and apocynin molecules on saving the tissues in the burn zone of stasis. Methods: The study was conducted with 48 rats. The burn zone of stasis was created according to the pattern previously described in the literature as comb burn model. In the 21-day study, biopsies were taken for histological examination on the 3rd, 7th and 21st days of the study. In addition, macroscopic photographic analysis was performed. Biopsies were taken for biochemical analysis on the 21st day. Histologically, inflammation, reepithelialization, and collagenization were evaluated, and the CD34 immunoreactivity was analysed. Biochemically, CAT, SOD, tGSH, TAS, TOS, MDA and PPC values were determined. Results: In the histological examination, on the 3rd, 7th and 21st days, inflammation was found to be reduced in the groups given taurine and apocynin on the 3rd day. On the 7th day, better reepithelialization and collagenization were observed in the group given taurine. Significant reepithelialization, collagenization and hair follicle development were observed in the groups given taurine and apocynin on the 21st day. In the biochemical analysis, the effects of apocynin on antioxidant enzymes were determined to be prominent. While we found no significant difference on the 3rd and 7th days in the photographic analysis, taurine and apocynin were observed to act synergistically on the 21st day and significantly reduced the burned areas. Conclusion: On the 3rd day, taurine and apocynin prevented inflammation, the effects of taurine in the zone of stasis in the early period (7th day) are more pronounced, the effect of apocynin on antioxidant enzymes is more pronounced. In the late period (21st day), taurine and apocynin were found to be more effective in saving the zone of stasis by creating a synergistic effect. (c) 2022 Elsevier Ltd and ISBI. All rights reserved.Öğe Enhancement of enzyme activity by laser-induced energy propulsion of upconverting nanoparticles under near-infrared light: A comprehensive methodology for in vitro and in vivo applications(Elsevier, 2024) Ates, Burhan; Ulu, Ahmet; Asilturk, Meltem; Noma, Samir Abbas Ali; Topel, Seda Demirel; Dik, Gamze; Ozhan, OnuralIf the appropriate immobilization method and carrier support are not selected, partial decreases in the activity of enzymes may occur after immobilization. Herein, to overcome this challenge, an excitation mechanism that enables energy transfer was proposed. Modified upconverting nanoparticles (UCNPs) were constructed and the important role of near-infrared (NIR) excitation in enhancing the catalytic activity of the enzyme was demonstrated. For this purpose, UCNPs were first synthesized via the hydrothermal method, functionalized with isocyanate groups, and then, PEG-L-ASNase was immobilized via covalent binding. UCNPs with and without PEG-LASNase were extensively characterized by different methods. These supports had immobilization yield and activity efficiency of >96 % and 78 %, respectively. Moreover, immobilized enzymes exhibited improved pH, thermal, and storage stability. In addition, they retained >65 % of their initial activity even after 20 catalytic cycles. Biochemical and histological findings did not indicate a trend of toxicity in rats due to UCNPs. Most importantly, PEG-L-ASNase activity was triggered approximately 5- and 2-fold under in vitro and in vivo conditions, respectively. Overall, it is anticipated that this pioneering work will shed new light on the realistic and promising usage of NIR-excited UCNPs for the immobilization of enzymes in expensive and extensive applications.Öğe Evaluation of xanthine oxidase inhibitor properties on isoindoline-1,3-dion derivatives and calculation of interaction mechanism(Elsevier, 2020) Gundugdu, Ozlem; Noma, Samir Abbas Ali; Taskin-Tok, Tugba; Ates, Burhan; Kishali, NurhanThe aim of the present study was to synthesis of isoindole-1,3(2H)-dione (Phthalimides) derivatives and to investigation the inhibition of xanthine oxidase (XO). In study, xanthine oxidase inhibitory activities of complexes were observed in the range from 7.15 to 22.56 mu M for isoindole-1,3-dione (2a-c and 3a-c). N-phenyl isoindole-1,3-dione derivatives (2c, 3c) showed better activity (almost two times) than the other two derivatives (N-methyl (2a, 3a), N-ethyl (2b, 3b). It means that phenyl ring (R) remarkably enhances the xanthine oxidase inhibitory effect of complexes. In the meantime, molecular docking studies of these compounds against XO were also investigated by providing the inhibitory efficiency and estimating the interaction mechanisms of isoindol-1,3-dion derivatives with XO. (C) 2019 Elsevier B.V. All rights reserved.Öğe Fabrication and characterization of high molecular mass tmpe-based polyurethane wound dressing materials containing allantoin and gentamicin by electrospinning(Eurasia Acad Publ Group (Eapg), 2023) Cakmen, Ayse Basak; Noma, Samir Abbas Ali; Gurses, Canbolat; Koytepea, Suleyman; Ates, Burhan; Yilmaz, IsmetIn this study, biocompatible, antibacterial and high mechanical strength polyurethane-based wound dressing materials were prepared by using the electrospinning technique. In addition, allantoin and gentamicin which will contribute to wound healing, were incorporated into these fiber materials. Polyurethane structures containing trimethylolpropane ethoxylate (TMPE) with 2 different molecular weights were synthesized. TMPE-based polyurethanes/polycaprolactone (1:3) blends were also prepared by adding 1% gentamicin and 10% allantoin and they were knitted by the electrospinning method and turned into a wound dressing material. After this stage, chemical structure, morphological, thermal and mechanical properties, flexibility, antibacterial effect, in vitro biocompatibility, cell adhesion tests, allantoin release level, and biodegradability of the prepared wound dressing materials were performed. The prepared fiber materials exhibited antibacterial properties and 80% cell viability, approximately. In addition, the obtained wound dressing materials showed high mechanical strength and ideal gas permeability. For this reason, it offers an ideal alternative for closing wounds.Öğe Fast Curing Multifunctional Tissue Adhesives of Sericin-Based Polyurethane-Acrylates for Sternal Closure(Amer Chemical Soc, 2022) Balcioglu, Sevgi; Noma, Samir Abbas Ali; Ulu, Ahmet; Karaaslan-Tunc, Merve Goksin; Ozhan, Onural; Koytepe, Suleyman; Parlakpinar, HakanThe use of wire cerclage after sternal closure is the standard method because of its rigidity and strength. Despite this, they have many disadvantages such as tissue trauma, operatorinduced failures, and the risk of infection. To avoid complications during sternotomy and promote tissue regeneration, tissue adhesives should be used in post-surgical treatment. Here, we report a highly biocompatible, biomimetic, biodegradable, antibacterial, and UV-curable polyurethane-acrylate (PU-A) tissue adhesive for sternal closure as a supportive to wire cerclage. In the study, PU-As were synthesized with variable biocompatible monomers, such as silk sericin, polyethylene glycol, dopamine, and an aliphatic isocyanate 4,4'-methylenebis(cyclohexyl isocyanate). The highest adhesion strength was found to be 4322 kPa, and the ex vivo compressive test result was determined as 715 kPa. The adhesive was determined to be highly biocompatible (on L929 cells), biodegradable, and antibacterial (on Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus bacteria). Finally, after opening the sternum of rats, the adhesive was applied to bond the bones and cured with UV for 5 min. According to the results, there was no visible inflammation in the adhesive groups, while some animals had high inflammation in the cyanoacrylate and wire cerclage groups. These results indicate that the adhesive may be suitable for sternal fixation by preventing the disadvantages of the steel wires and promoting tissue healing.Öğe L-asparaginase immobilized p(HEMA-GMA) cryogels: A recent study for biochemical, thermodynamic and kinetic parameters(Elsevier Sci Ltd, 2021) Noma, Samir Abbas Ali; Acet, Omur; Ulu, Ahmet; Onal, Burcu; Odabasi, Mehmet; Ates, BurhanCryogels have recently been attracted intense attention as suitable carriers for enzyme immobilization. Herein, L-asparaginase was selected as the model enzyme due to its application such as pharmaceutical and food. Under optimum conditions, L-asparaginase was immobilized on poly (2-hydroxyethyl methacrylate-glycidyl methacrylate) cryogels with 68.8% of immobilization yield and 69.3% of activity recovery. The immobilized enzyme exhibited improved stability with respect to the soluble enzyme at extreme conditions, especially around acidic pH and high temperature. Also, the storage stability and reusability of the immobilized enzyme were found to be approximately 54% and 52% of the original activity after 28 days at room temperature and 10 cycles, respectively. The thermodynamic studies indicated that activation energy (E-a) of the free enzyme decreased from 13.08 to 10.97 kJ/mol, which means an increase in the thermostability of L-asparaginase. The Michaelis-Menten constants (K-m) of 2.04 and 1.67 mM, and the maximum reaction rates (V-max) of 170.0 and 115.0 mu M min(-1) were estimated for soluble and immobilized L-asparaginase, respectively. These findings demonstrated that the designed cryogels turn out to be a good carrier matrix for L-asparaginase immobilization with high catalytic efficiency and enhanced stability.Öğe Magnetic Fe3O4@MCM-41 core-shell nanoparticles functionalized with thiol silane for efficient l-asparaginase immobilization(Taylor & Francis Ltd, 2018) Ulu, Ahmet; Noma, Samir Abbas Ali; Koytepe, Suleyman; Ates, BurhanL-Asparaginase (L-ASNase) is a vital enzyme for medical treatment and food industry. Here, we assessed the use of Fe3O4@Mobil Composition of Matter No. 41 (MCM-41) magnetic nanoparticles as carrier matrix for L-ASNase immobilization. In addition, surface of Fe3O4@MCM-41 magnetic nanoparticles was functionalized with 3-mercaptopropyltrimethoxysilane (MPTMS) to enhance stability of L-ASNase. The chemical structure, thermal properties, magnetic profile and morphology of the thiol-functionalized Fe3O4@MCM-41 magnetic nanoparticles were characterized with Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), differential scanning calorimetry (DSC), vibrating sample magnetometer (VSM), scanning electron microscope (SEM), energy dispersive X-ray (EDX) spectroscopy and zeta-potential measurement. L-ASNase was covalently immobilized onto the thiol-functionalized Fe3O4@MCM-41 magnetic nanoparticles. The properties of the immobilized enzyme, including optimum pH, temperature, kinetic parameters, thermal stability, reusability and storage stability were investigated and compared to free one. Immobilized enzyme was found to be stable over a wide range of pH and temperature range than free enzyme. The immobilized L-ASNase also showed higher thermal stability after 180 min incubation at 50 degrees C. The immobilized enzyme still retained 63% of its original activity after 16 times of reuse. The Km value for the immobilized enzyme was 1.15-fold lower than the free enzyme, which indicates increased affinity for the substrate. Additionally, the immobilized enzyme was active over 65% and 53% after 30 days of storage at 4 degrees C and room temperature (similar to 25 degrees C), respectively. Thereby, the results confirmed that thiol-functionalized Fe3O4@MCM-41 magnetic nanoparticles had high efficiency for L-ASNase immobilization and improved stability of L-ASNase.Öğe Melatonin protects sperm cells of Capoeta trutta from toxicity of titanium dioxide nanoparticles(Springer Heidelberg, 2020) Ozgur, Mustafa Erkan; Ulu, Ahmet; Noma, Samir Abbas Ali; Ozcan, Imren; Balcioglu, Sevgi; Ates, Burhan; Koytepe, SuleymanIn this study, it was aimed to determine the protective effects of melatonin (0.01, 0.1, and 1 mM) against 10 mg/L titanium dioxide nanoparticles (TiO2-NPs) on kinematic and oxidative indices in the sperm cells of Capoeta trutta. Therefore, TiO2 nanoparticles were synthesized primarily within the scope of the study. The synthesized nanoparticles were characterized by structurally different techniques. Then, melatonin and TiO2 were applied to Capoeta trutta sperm cells by in vitro. According to our data, all doses of melatonin showed protective effects on all velocities of sperm cells such as the straight line velocity (VSL), the curvilinear velocity (VCL), and the angular path velocity (VAP) against TiO2-NPs, while 0.1 and 1 mM doses of melatonin improved the VSL value. Although TiO2-NPs increased total glutathione (tGSH), malondialdehyde (MDA) lipid peroxidation, and superoxide dismutase (SOD) compared to the control group, there were positive treatment effects for all doses of melatonin on antioxidant capacity of sperm cells. At the end of this research, it is suggested that over 0.1 mM dose of melatonin improves the velocity of sperm cells and it plays a protective role against the toxic effects of TiO2-NPs.Öğe Near-infrared inducible supports in bio-catalysts design: A useful and versatile tool in enhancement of enzyme activity(Elsevier, 2024) Noma, Samir Abbas Ali; Dik, Gamze; Gurses, Canbolat; Kurucay, Ali; Topel, Seda Demirel; Ulu, Ahmet; Asiltuerk, MeltemImmobilized enzymes have encountered two main challenges: Reduced enzyme activity compared to free enzymes and exhausted immobilized enzymes due to reusability. Herein, we suggested a promising activity enhancement strategy to overcome these challenges. The emission from upconversion nanoparticles (UCNPs) under near-infrared (NIR) excitation can increase the activity of PEG-L-ASNase due to Forster Resonance Energy Transfer. For this purpose, UCNPs were initially synthesized using the hydrothermal method. Subsequently, these UCNPs were functionalized with a polycationic polymer, branched polyethyleneimine (PEI), and the immobilization of PEG-L-ASNase was achieved through adsorption. We preliminarily explored the parameters such as enzyme concentration, incubation time, pH, temperature, reusability, storage stability, and kinetic study, etc. Further, the in vitro biocompatibility, hemolytic behavior, and anticancer activity of the produced UCNPs were also analyzed as crucial parameters. The results showed the pH durance, thermal and storage stability of the immobilized PEG-L-ASNases were enhanced. The immobilized PEG-L-ASNases maintained their activity to >= 55 % after 20 cycles. Enzyme immobilization led to a decrease in Km and Vmax compared to PEG-L-ASNase. In vitro assays revealed that immobilized enzyme further reduced the proliferation of human leukemia cell line (HL-60) upon NIR irradiation exposure but did not cause toxicity. This research may provide a new strategy to promote the catalytic activity of L-ASNase and demonstrates its potential application on human leukemia cells. Finally, these outcomes are valuable for the use of NIR induction in enzymatic reactions.Öğe New 2-hydroxyethyl substituted N-Heterocyclic carbene precursors: Synthesis, characterization, crystal structure and inhibitory properties against carbonic anhydrase and xanthine oxidase(Elsevier Science Bv, 2019) Aktas, Aydin; Noma, Samir Abbas Ali; Celepci, Duygu Barut; Erdemir, Fatos; Gok, Yetkin; Ates, BurhanHere, the synthesis, spectral and the structural studies of 2-hydroxyethyl substituted N-heterocyclic carbene (NHC) precursors and the enzyme inhibition activities of the NHC precursors were investigated against the cytosolic carbonic anhydrase I and II isoenzymes (hCA I and hCA II), and xanthine oxidase (XO). The IC50 values of NHC precursors against these enzymes were determined by spectrophotometric method. The spectra of new NHC precursors have been obtained by using H-1 NMR, C-13 NMR, FTIR spectroscopy and elemental analysis techniques. The structure of a new NHC precursor was established by using single-crystal X-ray diffraction method. The results of inhibition experiment indicated that all 2-hydroxyethyl substituted NHC derivatives showed remarkable inhibition activity toward hCA I, hCA II and XO. The range of IC50 values for hCA I, hCA II and XO inhibition was determined as 0.1565-0.5127, 0.1524-0.5368 and 1.253-5.342 mu M. Especially, trimethylbenzyl derivative of 2-hydroxyethyl substituted NHC precursor has demonstrated high inhibition effect on all studied enzymes due to steric bulk of this substituent. (C) 2019 Elsevier B.V. All rights reserved.Öğe The (NHC)PdBr2(2-aminopyridine) complexes: synthesis, characterization, molecular docking study, and inhibitor effects on the human serum carbonic anhydrase and serum bovine xanthine oxidase(Springer Wien, 2020) Turker, Ferhat; Noma, Samir Abbas Ali; Aktas, Aydin; Al-Khafaji, Khattab; Tok, Tugba Taskin; Ates, Burhan; Gok, YetkinThis study contains the synthesis, spectral analysis, and the enzyme inhibition effects of the Pd-based complexes bearing both 2-aminopyridine andN-heterocyclic carbene (NHC) ligands. The NHC ligand in the Pd-based complexes contains the 3-cyanobenzyl group. All new complexes were synthesized from (NHC)PdBr2(pyridine) complexes and 2-aminopyridine. These new complexes were characterized by using elemental analysis,H-1 NMR,C-13 NMR, and FT-IR spectroscopy techniques. Furthermore, inhibitor effects of these complexes were also tested toward some metabolic enzymes such as carbonic anhydrase and xanthine oxidase enzymes. The IC50 range for hCA I, hCA II, and XO were determined as 0.325-0.707, 0.238-0.636, and 0.576-1.693 mu M, respectively. These data showed that Pd(II)-NHC complexes bearing 2-aminopyridine may be potent inhibitors of hCA and XO enzymes. Besides these applications, molecular docking was performed by using CDOCKER tool as a part of Discovery studio 2019, not only to determine the binding mode of synthesized inhibitors, but also to determine the correlation between the CDOCKER score values and IC50 values. We found a good correlation (R-2 = 0.7403) between IC50 and the CDOCKER score of the inhibitors for XO. These findings could be a reference to start the development of effective medicine for XO. [GRAPHICS] .Öğe Preparation and characterization of amino and carboxyl functionalized core-shell Fe3O4/SiO2 for L-asparaginase immobilization: A comparison study(Taylor & Francis Ltd, 2020) Noma, Samir Abbas Ali; Ulu, Ahmet; Koytepe, Suleyman; Ates, BurhanMagnetic nanoparticles are well known as facile and effective support for enzyme immobilization since they have a high surface area, large surface-to-volume ratio, easy separation, a fast and high enzyme loading. This study aims to provide insights on whether acidic or basic modified particles are more effective for L-asparaginase (ASNase) immobilization. Therefore, amino (Fe3O4/SiO2/NH2) and carboxyl-functionalized (Fe3O4/SiO2/COOH) particles were prepared. The functional groups, crystalline structure, magnetic properties, morphology, chemical composition and thermal behaviour of the prepared modified nanoparticles were examined via Fourier-transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), vibrating-sample magnetometer (VSM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDAX). Under the optimum conditions, the immobilized enzymes were more stable within a certain range of temperatures and pH values in comparison to free enzyme. On the other hand, the immobilized enzymes showed greater stability after incubation for 3 h at 50 degrees C. The free enzyme maintained only 30% of its initial activity for 4 weeks at 4 degrees C, while Fe3O4/SiO2/NH2/ASNase and Fe3O4/SiO2/COOH/ASNase retained more than 78.9% and 56.5% of initial activities under the same conditions, respectively. Moreover, Fe3O4/SiO2/NH2/ASNase (77.2%) and Fe3O4/SiO2/COOH/ASNase (57.4%) displayed excellent operational stability after 17 repeated cycles. These findings suggested that the Fe3O4/SiO2/NH2 and Fe3O4/SiO2/COOH may be utilized as efficient and sustainable supports to developed immobilized ASNase in several biotechnological applications.Öğe Preparation, characterization of upconverting nanoparticles for uricase immobilization and controlled manipulation of uricase activity by near-infrared light(Elsevier, 2024) Dik, Gamze; Noma, Samir Abbas Ali; Ulu, Ahmet; Topel, Seda Demirel; Asiltuerk, Meltem; Ates, BurhanIn recent years, studies on the external stimulation of biotechnological enzyme drugs and their use in the treatment of diseases have gradually increased. Herein, for the first time, the near-infrared (NIR) was used as an external stimulant to manipulate the catalytic activity of the uricase (UOx) enzyme, which is used in the treatment of hyperuricemia, in a controlled manner. For this purpose, NaYF4: Yb3+, Er3+ upconverting nanoparticles (UCNPs) were synthesized by hydrothermal synthesis method and functionalized with diethylaminoethyldextran (DEAE-D) to facilitate UOx immobilization. The obtained materials were characterized in detail by various methods to confirm the preparation of UCNPs and immobilization of UOx. In addition, the biochemical parameters such as optimum pH, optimum temperature, thermal stability, and reusability were preliminarily investigated for free UOx and NaYF4: Yb3+, Er3+/DEAE-D/UOx. Moreover, a sequential experimental method was monitored to assess the effects of NIR excitation intensity, induction distance, and exposure time on the UOx activity. While the optimum pH value was found to be 6.0 for both enzyme forms, the optimum temperature value was recorded as 45 and 50 degrees C for free UOx and NaYF4: Yb3+, Er3+/DEAE-D/UOx, respectively. The activation energy (Ea) values of free UOx and NaYF4: Yb3+, Er3+/DEAE-D/UOx were calculated to be 7.59 and 2.98 kJ/mol, respectively, implying that the NaYF4: Yb3+, Er3+/DEAE-D/UOx was less temperature sensitive. After thermal incubation for 3 h at 55 degrees C, the NaYF4: Yb3+, Er3+/DEAE-D/UOx retained 54.68 % of its initial activity, while the free UOx retained 32.94 % of its initial activity at 50 degrees C. In addition, the findings from the reusability experiments revealed that NaYF4:Yb3+, Er3+/DEAE-D/UOx retained 57.94 % of its initial activity even after 10 reuse cycles. The most striking point in this study was the positive manipulation of UOx activity by NIR. Accordingly, it was observed that when the NIR power was 1500 mW, the UOx activity increased about 2 times compared to the control. Additionally, the UOx activity increased in parallel with the increase in NIR application time and the ideal application distance was 3 cm. In conclusion, this pioneering study provides valuable insights into the controlled manipulation of enzyme activity, showcasing the effectiveness of NIR in enhancing enzyme activity. The outcomes suggest that NIR holds great promise as an efficient, sustainable, and versatile approach applicable to various enzymatic catalysis scenarios.