Person: OGAN, AYŞE
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OGAN
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AYŞE
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Publication Metadata only Soybean oil based resin: A new tool for improved immobilization of alpha-amylase(WILEY, 2006) OGAN, AYŞE; Kahraman, MV; Kayaman-Apohan, N; Ogan, A; Gungor, AAcrylated epoxidized soybean resin has been utilized to immobilize the alpha-amylase via UV-curing technique. Among the numerous methods that exist for enzyme immobilization, entrapment and covalent binding are the focus of this study. The properties of immobilized enzyme were investigated and compared with those of the free enzyme. Upon immobilization by the two methods, the catalytic properties of the enzyme were not considerably changed as compared with that of nonimmobilized form; enzyme. The free enzyme lost its activity completely in 20 days, where as storage and repeated usage capability experiments demonstrated higher stability for the immobilized form. Immobilized enzyme prepared by attachment method possesses relatively higher activity compared with the activity of those obtained by entrapment method. (c) 2006 Wiley Periodicals, Inc.Publication Open Access Alterations in the kinetic activity of aromatlc-L-amino acid decarboxylase and preliminary 2-DE investigation of the brains in a 6-OHDA induced Parkinson's disease rat model(2003-07-01) OGAN, AYŞE; ONAT, FİLİZ; GÜLHAN, REZZAN; Günel A., OGAN A., ONAT F., GÜLHAN R.Objective: The aim of this study was to isolate and purify the aromatic-L-amino acid decarboxylase (AADC,EC 4.1.1.28) enzyme rats from Parkinson\"s Disease (PD) induced and the healthy control group rat brains and compare the alterations in the kinetic activities of the isolated enzyme. The protein spots displaying on the 2-DE patterns of the diseased and the healthy control group crude rat brain homogenates were evaluated. Medhods: In this study, the Parkinson\"s Disease model was induced by injecting 6-hydroxydopamine into the brains of the rats. The PD model formation was successful in two rats out of three. Results: The AADC decarboxylase was isolated and partially purified by DEAE-Sephacel ion exchange chromatography from the brains of PD induced and healthy control animals to compare the kinetic activity of the enzyme. The kinetic activity of the enzyme was reduced 70% in the PD group compared to controls. In order to determine and correlate the alterations with PD, and the distribution of the proteins displayed by the crude brain homogenates of the diseased and the healthy control group both were investigated. Polyacrylamide gel electrophoresis (PAGE) of the crude brain homogenates under the native and denaturizing conditions displayed matching bands for both of the groups, while two dimensional electrophoresis (2-DE) patterns of the crude brain homogenates of the diseased and the control group displayed considerable differences. Conclusion: The results of this study confirm the power of 2-DE-PAGE technique of the proteome analysis. Currently only the proteome analysis enables the identification of disease correlated proteins.Publication Metadata only Anne sütünden insülin benzeri büyüme faktörü-I (igf-I) bağlayıcı proteinlerin ligand blot metodu ile analizi(2002-06-24) OGAN, AYŞE; Yeldan M., Ogan A.Publication Open Access Spectrophotometric determination of leukocytes in urine(WILEY, 2004) OGAN, AYŞE; Imren-Eryilmaz, E; Kuzu-Karsilayan, H; Ogan, AA spectrophotometric method based on myeloperoxidase activity for the determination of leukocytes in urine is described. Red cells that may be found in urine samples were lysed by an ammonium chloride method. Leukocytes were then sedimented by centrifugation and lysed using Triton X-100 (Sigma Chemicals Co., St. Louis, MO). Myeloperoxidase-catalyzed oxidation of o-dianisidine was carried out at 37degreesC, pH 7. The reaction was stopped with the addition of 2 M H2SO4, and a stable form of oxidized o-dianisidine in acidic solution was obtained. Solid particles that may be found in urine samples were removed by centrifugation to avoid turbidity, and absorbance values of the supernatants were recorded at 400 rim. An Average number of leukocytes were noted per number of fields by microscopic examination and were related with the absorbance values of the supernatants at 400 nm. Pearson correlation (r) between our presented spectrophotometric analysis results and visual microscopic analysis was 0.877. Roche Combur 10-test M strips (Roche, Mannheim, Germany) and Multistix 10 SG Bayer test strips (Bayer Diagnostics, UK) were 0.645 and 0.648, respectively (P < 0.0001). (C) 2004 Wiley-Liss, Inc.Publication Metadata only Preparation, characterization, and drug release properties of poly(2-hydroxyethyl methacrylate) hydrogels having beta-cyclodextrin functionality(JOHN WILEY & SONS INC, 2008) OGAN, AYŞE; Demir, Serap; Kahraman, M. Vezir; Bora, Nil; Apohan, Nilhan Kayaman; Ogan, AyseA new beta-cyclodextrin urethane-methacrylate monomer was synthesized from the reaction of toluene-2,4-diisocyanate, 2-hydroxyethyl methacrylate (HEMA), and beta-cyclodextrin (beta-CD). Based on inclusion character of beta-CD, a series of hydrogels were prepared by irradiating the mixtures of beta-cyclodextrin urethane-methacrylate monomer (beta-CD-UM), poly(ethylene glycol) diacrylate (PEG-DA), HEMA, and the photoinitator. Gel percentages and equilibrium swelling ratios (%) of hydrogels were investigated. It was observed that the equilibrium-swelling ratio increased with increasing beta-CD-UM content in the hydrogel composition. SEM images demonstrated that beta-CD-UM based hydrogel have porous fractured surface. In this study four different drug molecules, salicylic acid, sulfathiazole, rifampicin, and methyl orange as model drug, which are capable of forming inclusion complexes with beta-CD were chosen. For sulfathiazole and rifampicin, the drug loadings are very low (0.04 and 0.008 mmol/g dry gel), whereas methyl orange and salicylic acid drug uptakes are found as 0.15 and 0.18 mmol/g dry gel, respectively. The incorporation of beta-CD-UM comonomer into the gel slightly reduces the methyl orange and salicylic acid releases. However, a significant enhancement was achieved in the case of sulfathiazole delivery. It can be concluded that the inclusion complex formation capability of beta-CD moiety increases the drug release by improving the aqueous solubility of hydrophobic drugs. On the other hand, in the case of hydrophilic drugs, the drug release retards by forming strong drug-beta-CD complex and reducing the drug diffusivity. (C) 2008 Wiley Periodicals, Inc.Publication Metadata only Extremely halophilic Archaea from Tuz Lake, Turkey, and the adjacent Kaldirim and Kayacik salterns(SPRINGER, 2007) OGAN, AYŞE; Birbir, Meral; Calli, Baris; Mertoglu, Bulent; Bardavid, Rahel Elevi; Oren, Aharon; Ogmen, Mehmet Nuri; Ogan, AyseTuz Lake is a hypersaline lake located in Central Anatolia, Turkey. The lake and its salterns, Kaldirim and Kayacik, are the major sources of solar salt for industrial applications in Turkey, especially in the food and leather industries. Use of the crude solar salt often results in microbial deterioration of the products. We therefore initiated a thorough characterization of the microbial communities in Tuz Lake and its adjacent salterns, and we present here the results of investigations on diversity of extremely halophilic Archaea. Twenty-seven colonies of aerobic red or pink Archaea (family Halobacteriaceae) were selected according to colony shape, size, consistency and pigmentation, and characterized according to their phenotypic characteristics, polar lipid contents, and antibiotic sensitivities. Furthermore, 16S rRNA genes of the isolates were screened by DGGE analysis and partially sequenced. Phylogenetic analysis showed that most isolates belonged to the genera Haloarcula, Halorubrum and Halobacterium. Haloarcula was found to be dominant both in Tuz Lake and in the saltern samples. Halorubrum species were isolated from Tuz Lake and from the Kaldirim saltern, and Halobacterium species were recovered from Tuz Lake and from the Kayacik saltern. All strains showed various activities of hydrolytic enzymes (proteases, amylases, cellulases, and others), activities which are responsible for the detrimental effects of the crude salt in food and leather products.Publication Metadata only Intrinsic factor and vitamin B12 complex-loaded poly[lactic-co-(glycolic acid)] microspheres: preparation, characterization and drug release(WILEY, 2008) OGAN, AYŞE; Demir, Serap; Ogan, Ayse; Kayaman-Apohan, NilhanBACKGROUND: Vitamin B12 is an essential vitamin required by all mammals. Absorption of vitamin B12 is facilitated by binding of intrinsic factor-vitamin B12 complex to specific receptors in the ileum. In humans a deficiency of this vitamin or a lack of intrinsic factor leads to pernicious anaemia. The major objective of the present study was to prepare intrinsic factor-vitamin B12 complex-loaded poly[lactic-co-(glycolic acid)] (PLGA)-based microparticles and to investigate their release kinetics. RESULTS: PLGA copolymer was synthesized by the ring-opening polymerization method and characterized using gel permeation chromatography, Fourier transform infrared spectroscopy and H-1 NMR. The glass transition temperature measurement showed a single T-g at 40 degrees C. The intrinsic factor-vitamin B12 complex-loaded PLGA microspheres were prepared by a water-in-oil-in-water double emulsion solvent extraction/evaporation technique. An environmental scanning electron microscopy investigation demonstrated that the PLGA particles had a mean particle diameter of 38 gm. Interestingly, different drug release patterns (bi- and triphasic ones) were observed for vitamin B12-loaded and intrinsic factor-vitamin B12 complex-loaded microspheres. In contrast to the rapid release of vitamin B12 by itself, in vitro release tests showed that intrinsic factor and vitamin B12 in the complex were released from PLGA microspheres in a sustained manner over 15 days. CONCLUSION: PLGA microspheres can be an effective carrier for the intrinsic factor-vitamin B12 complex. (C) 2007 Society of Chemical Industry.