Yazar "Dincer, Barbaros" seçeneğine göre listele
Listeleniyor 1 - 5 / 5
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Characterization of a novel lipase bound to the Geobacillus stearothermophilus AH22 membrane(Springer Heidelberg, 2025) Dincer, Barbaros; Iskender, Engin; Kizil, Demet; Adiguzel, AhmetLipases (EC 3.1.1.3), used in many industrial applications, hydrolyze tri-, di-, and monoglycerides to free fatty acids and glycerol. This study aimed to determine the capacity of Geobacillus stearothermophilus AH22 for membrane-bound lipase production and to identify the optimal medium for lipase production. Following the determination of certain parameters such as pH and temperature, where the produced membrane-bound lipase exhibits the best activity, the kinetic data, as Km and Vmax, were obtained in the presence of p-NPA (0.03 +/- 0.008 mM and 0.7 +/- 0.18 U), p-NPB (0.7 +/- 0.18 mM and 3.4 +/- 0.40 U), p-NPO (0.12 +/- 0.010 mM and 5.2 +/- 0.62 U), and p-NPL (0.01 +/- 0.003 mM and 0.8 +/- 0.15 U) substrates. The highest activity of AH22 membrane-bound lipase was observed at pH 9.0 in the presence of substrates, at temperatures ranging from 20 to 40 degrees C for substrates with low carbon chains fatty acids and from 50 to 60 degrees C for substrates with long carbon chains. Also, it was observed that the cells dried by lyophilization showed lipase activity after they were pulver-ized. However, in terms of reuse, it was determined that wet cells were more efficient than powdered cells. It was found that the activity of the AH22 membrane-bound lipase had not changed much in the presence of anions and cations but decreased significantly in the presence of detergents and beta-mercaptoethanol. The AH22 membrane-bound lipase can be directly used in other industrial areas where lipase is used, except for the detergent industry, without requiring additional and expensive processing such as purification or immobilization.Öğe Inhibition and purification of acetylcholinesterases from adults and nymphs of Ricania simulans (Walker, 1851) (Hemiptera: Ricaniidae)(Springer Int Publ Ag, 2022) Dincer, Barbaros; Kizil, DemetRicania simulans (Walker, 1851) (Hemiptera: Ricaniidae) has been causing damage in agricultural areas along the eastern Black Sea coastline since 2006. As there are not enough studies on managing this pest, it continues to pose a threat. One of the significant control tactics of insecticides includes the inhibition of acetylcholinesterase. Therefore the present study is aimed to study an alternative way to combat R. simulans through inhibition of acetylcholinesterase (ACHE). The ACHE was purified from adults and nymphs of R. simulans one by one using one-step edrophonium-Sepharose 6B affinity chromatography, and some kinetic properties were studied. The ACHEs were purified 251.6-fold with a yield of 34.2% for adults and 65.5-fold with a yield of 2.2% for nymphs. The K-m, V-max, and k(cat) values of R. simulans ACHE for acetylthiocholine iodide (ATC) hydrolysis were determined to be 0.04 +/- 0.01 mM, 2,000.0 +/- 250 EU/mg protein and 104.5 +/- 13 min(-1) for adults and 0.02 +/- 0.01 mM, 500.0 +/- 52 EU/mg protein and 30.3 +/- 6.4 min(-1) for nymphs, respectively. In inhibition studies of R. simulans ACHEs with edrophonium chloride, tacrine and olive leaf extract with water, the IC50 values of the inhibitors were calculated. Although all inhibitors inhibited the ACHEs, they inhibited the nymphs' ACHEs more effectively. In particular, the fact that the olive leaf water extract is effective in the ACHEs inhibition of these two stages is important for it to be an environmentally friendly pesticide that can be used in the fight against this pest.Öğe Production Starch Using the Yeast (Cryptococcus neoformans HTM1 Strain) Isolated From Tea (Camellia sinensis)(Wiley-V C H Verlag Gmbh, 2025) Dincer, Barbaros; Haciosmanoglu, Emine; Kizil, Demet; Alpay Karaoglu, SengulStarch is a staple food in human and animal nutrition as well as a widely used raw material in industry. This study determined the capacity of producing starch of a new yeast culture, which was defined as Cryptococcus neoformans HTM1 strain by a definitive molecular diagnosis method and isolated from tea (Camellia sinensis). The produced starch was identified as wheat starch. It was established that the HTM1 strain produced 0.23 mg/mL starch with glucose, 0.30 mg/mL with fructose, and 0.37 mg/mL with sucrose. The HTM1 strain can produce starch in media with honey and waste fruit juices; the amounts of starch were calculated as 1.2 mg/mL from honey, 1.1 mg/mL from pomegranate, 0.8 mg/mL from apple, 0.9 mg/mL from tangerine, and 0.8 mg/mL from kiwi. In conclusion, in this study, it was determined that the yeast strain C. neoformans HTM1 isolated from tea can produce starch and has the potential to produce starch in vitro regardless of environmental conditions.Öğe Synthesis, characterization, colorimetric sensor and acetylcholinesterase inhibition studies of novel benzimidazole-based hydroxamic acids(Elsevier, 2025) Yilmaz, Fatih; Kizil, Demet; Dincer, Barbaros; Karaoglu, KaanTwo new hydroxamic acid molecules 2-(2-Pyridyl)benzimidazole-N-acetohydroxamic acid (HL1), 2-(2-Pyridyl) benzimidazole-N-butanohydroxamic acid (HL2), can be used in Fe(III) detection and pest control, have been synthesized first time and characterized using Elemental Analysis, 1H NMR, 13C NMR, FT-IR, LC-MS (ESI+) spectrometry. Selectivity of the HL1 and HL2 towards Fe3+ ion were tested against in the presence of the competitive metal ions and found to be highly effective agents for the determination of Fe3+ ions in the presence of these ions. The limits of detection of Fe(III) ions using these ligands were found 1.9 mu M and 0.7 mu M, respectively. Metal complexes of HL1 and HL2 with Fe(III), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) were also synthesized to understand the complex formation in the solid phase and at higher pH. The results showed in the solid phase the M:L ratios of the complexes were 1:1 and 1:2 and the hydroxamate groups were in the keto form. The inhibition effects of HL1 and HL2 ligands on acetylcholinesterase (AChE) purified from Orosanga japonica (Melichar, 1898) (Homoptera: Ricaniidae) were determined. The ligands effectively inhibited acetylcholinesterase yet HL1 was more effective than HL2, IC50 values of 1.7 +/- 0.2 mM and 2.6 +/- 0.1 mM, respectively. These results indicated these newly synthesized benzimidazole-based hydroxamic acid ligands can serve as dualfunctional agents for both Fe3+ detection and pest control.Öğe Ternary Transition Metal Complexes with an Azo-Imine Ligand and 2,2?-Bipyridine: Characterization, Computational Calculations, and Acetylcholinesterase Inhibition Activities(Slovensko Kemijsko Drustvo, 2022) Serbest, Kerim; Dural, Turan; Kizil, Demet; Emirik, Mustafa; Zengin, Ali; Dincer, BarbarosNew mononuclear ternary transition metal complexes: [M(HL)(bipy)2]ClO4, (M: Mn(II) for 1, Ni(II) for 2), [M(HL) (bipy) (ClO4)], (M: Ni(II) for 3, Cu(II) for 4, Zn(II) for 5) with M(II), 2-[(hydroxyimino)methyl]-4-[-phenyldiazenyl] phenol, H2L, and 2,2'-bipyridine were synthesized, and their structures were investigated by using various analytical, spectroscopic techniques such as elemental analysis, FTIR, UV-Vis, NMR, MALDI-TOF mass spectrometry, thermal analysis. The theoretical studies were performed by DFT techniques by using B3LYP function with 6-311++G (d, p)/LanLD2Z basis set. The electronic transitions charters of the complexes were further analyzed by TD-DFT/CAM-B3LYP method. IR and thermal analysis data verify the proposed structures. The inhibition activities of the complexes against acetylcholinesterase (AChE) extracted from Ricania simulans adults and nymphs were examined and all the complexes were found to be active. Among the complexes studied, the highest inhibition activity was exhibited by complex 5 with the lowest IC50 value (3.2 +/- 0.8 mu M) for AChE of adults and complex 3 with the lowest IC50 value (4.6 +/- 0.8 mu M) for AChE of nymphs.
