Vedat Turkoglu

Hematotoxic and hepatotoxic effects of dichlorvos at sublethal dosages in rats

The present study was designed to understand the effects of sublethal concentrations of dichlorvos (DIC) on hematological constituent [red blood corpuscles, white blood corpuscles (WBC), mean cell volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, platelet counts, hemoglobin and hematocrite levels] and serum damage marker enzymes (aspartate aminotransferase, alanin aminotransferase, alkaline phosphatase, and lactate dehydrogenase) in rats at subacute period under laboratory conditions. DIC at dosages of 5 and 10 ppm was administered orally to six male rats ad libitum during the tests for 4 weeks consecutively. According to the results, DIC treatments increased significantly the levels of serum marker enzyme activities, whereas they did not change hematologic constituent except for WBC number treated with both dosages of DIC. The observations presented led us to conclude that the administrations of subacute DIC induced the levels of damage marker enzymes and leukocytosis.

Purification and characterization of acetylcholinesterase from the Lake Van fish (Chalcalburnus tarichii Pallas, 1811).

Abstract In this study, acetylcholinesterase (AChE; EC 3.1.1.7) was purified from plasma and erythrocytes in the Lake Van fish (Chalcalburnus tarichii P.1811) by affinity chromatography. Enzymatic activity was spectrophotometrically measured according to Ellman’s method, at 412 nm. Then, the optimal pH and temperature of the enzyme was determined. According to the results, the optimal pH and the optimum temperature were 8.0 and 25°C, respectively. In order to control the purification of the enzyme, sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was done. SDS-PAGE showed a single band for enzyme. The purification rates for plasma AChE and erythrocyte AChE are 3251.6 and 8500, respectively.

A novel nonenzymatic hydrogen peroxide amperometric sensor based on Pd@CeO 2 -NH 2 nanocomposites modified glassy carbon electrode

Herein, (3-aminopropyl)triethoxysilane functionalized cerium (IV) oxide (CeO2-NH2) supported Pd nanoparticles were synthesized. The nanocomposites were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and High-resolution transmission electron microscopy (HRTEM). The Pd@CeO2-NH2 showed better electrocatalytic response to the reduction of H2O2 than CeO2-NH2. The fabricated sensor exhibited two linear responses to the reduction of H2O2. The first one was from 0.001 to 3.276 mM with 0.47 μM of a limit of detection (LOD) (S/N = 3) and excellent sensitivity of 440.72 μA mM-1 cm-2 and the second one was from 3.276 to 17.500 mM with the sensitivity of 852.65 μA mM-1 cm-2 in the optimum conductions. Also, the sensor exhibited 91% of electrocatalytic activity toward H2O2 after having been used for 30 days and the reproducibility was also satisfactory. The sensor response to H2O2 was not affected by ascorbic acid, fructose, glycine, dopamine, arginine, mannose, glucose, uric acid, Mg+2, Ca+2, and phenylalanine at the studied potential. Also, the fabricated sensor was used to determine H2O2 in milk samples. The results show that the constructed sensor can be a promising devise for the determination of H2O2 in real samples.

Purification of angiotensin-converting enzyme from human plasma and investigation of the effect of some active ingredients isolated from Nigella sativa L. extract on the enzyme activity

In the present study, one-step purification of angiotensin-converting enzyme (ACE, peptidyldipeptidase A, EC 3.4.15.1), responsible for regulation of blood pressure, was achieved using affinity chromatography from human plasma. The enzyme was purified 12,860-fold with a specific activtiy of 5080 EU/mg protein. Optimum temperature and pH were determined for the enzyme as 35-40°C and pH 7.4-7.5, respectively. The purity of ACE was determined by SDS-PAGE and the enzyme showed two bands at 60 and 70 kDa on the gel. The native molecular weight of ACE was found to be 260 kDa by gel filtration chromatography, demonstrating that the enzyme has a heterodimeric structure. Natural fatty acids of Nigella sativa (Ranunculaceae) were isolated by means of column chromatography. The structures of these compounds were determined using NMR and GC-MS. The results showed that high concentrations of linoleic, oleic and palmitic acids were isolated from the plant. The effect of six fractions (Fr 1-6) on ACE activity was examined. Fraction 3 increased the ACE activity while the other fractions decreased the enzyme activity. The concentrations of the fractions inhibiting the half-maximum activity of the enzyme were calculated as 1.597 mg/mL for Fr 1, 0.053 mg/mL for Fr 2, 0.527 mg/mL for Fr 4, 0.044 mg/mL for Fr 5 and 0.136 mg/mL for Fr 6 using a Lineweaver-Burk graph.

In Vitro Inhibition of Human Plasma and Erythrocyte AChE by Various Drugs

Bu çalışmada; yapısal olarak farklı olan sekiz antibiyotik (sefazolin, kanamisin, gentamisin, klindamisin, ivermektin ve ampisilin) ve ağrı kesicinin (metamizol ve diklofenak) insan eritrosit ve plazma asetilkolinesteraz (AChE; EC 3.1.1.7) enzimi üzerine in vitro etkileri araştırılmıştır. Bu amaçla; farklı derişimlere sahip ilaçların neden olduğu inhibisyonu belirlemek için ilaçların IC 50 ve K I değerleri hesaplandı. Asetilkolinesteraz aktivitesi spektrofotometrik olarak Ellman yöntemiyle belirlendi. Daha sonra, ilaçlara maruz kalan enzim aktivitesi ölçüldü. AChE aktivitesine karşı ilaç derişimi ve Michealis-Menten grafikleri çizildi. Son olarak, bu grafikler yardımıyla IC 50 ve K ı değerleri hesaplandı. IC 50 değerleri, plazma AChE’sine diklofenak için 1.78 x10 M ve eritrosit AChE’sine gentamisin için 0.85 x10 M olduğu belirlendi. K I değerleri ise diklofenak için 1.36 x10 M ve gentamisin için 1.16 x10 M olarak hesaplandı. Ayrıca, ivermektin, klindamisin, kanamisin, ampisilin için IC 50 ve K I değerleri elde edildi. Diklofenak, plazma AChE aktivitesi üzerine gentamisin de eritrosit AChE aktivitesi üzerine en yüksek inhibitör etkisi göstermiştir. Bulunan bu değerlerin daha önce yapılan benzer çalışmalardaki inhibisyon değerlerinden daha yüksek olduğu görülmektedir [1,2].

The effect of some antibiotics on glutathione reductase enzyme purified from liver and erythrocyte of Lake Van pearl mullet.

Abstract Context: The effect of antibiotics (amikacin, cefazolin, ivermectin, and kanamycin) on glutathione reductase (GR) isoenzymes activity in liver and erythrocyte of the fish, Chalcalburnus tarichi (Lake Van pearl mullet, Pallas 1811) (Cyprinidae) were investigated. Objective: This study determined the biochemical characterization of GR purified from the liver and erythrocytes of C. tarichi and the inhibition effect of the antibiotics on the GR isoenzymes. Materials and methods: GR was purified by affinity chromatography from the tissues of C. tarichi. The biochemical characterization of GR such as optimum temperature, optimum pH, and ionic strength were determined. The inhibition effects of the antibiotics on the isoenzymes were evaluated as IC50 and Ki values. Ki constant and 50% inhibitory concentration (IC50) value for antibiotics were determined by Lineweaver–Burk graphs and plotting activity % versus [I], respectively, at five different concentrations of antibiotics. Results: Optimum temperature, pH, and ionic strength were determined for isoenzymes as 40 °C, 60 °C; 8.0, 8.0, and 50, 50 mM, respectively. Subunit molecular weights of the isoenzymes were estimated as 55 kDa by sodium dodecyl sulfate polyacrilamide gel electrophoresis (SDS-PAGE). In addition, IC50 and Ki values were calculated for amikacin, cefazolin, ivermectin, and kanamycin. The antibiotics showed non-competitive inhibition effects. IC50 values were calculated as 16.3, 36.6, 0.504, and 18.8 mM for liver and 20.0, 30.4, 0.787, and 31.8 mM for erythrocyte, respectively. Ki constants were 13.9, 18.4, 0.654, and 11.2 mM for liver and 23.2, 46.4, 1.19, and 36.4 mM for erythrocyte, respectively. Discussion and conclusion: The results indicated that the antibiotics displayed non-competitive inhibition.