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    Adsorption of Remazol Brilliant Blue R using ZnO fine powder: Equilibrium, kinetic and thermodynamic modeling studies
    (Elsevier, 2009) Ada, Kezban; Ergene, Aysun; Tan, Sema; Yalçın, Emine
    Zinc oxide powders with six-sided flake-like particles were prepared by homogeneous precipitation from boiling aqueous solutions that contained excess urea and 0.075 (Z075) and 0.300 (Z300) M Zn2+. The average sizes of the particles are 37 and 46 mu m, while the average sizes of the crystals are similar to 45 for Z075 and Z300 at 1000 degrees C. Equilibrium, kinetic and thermodynamic studies were carried out for the adsorption of RBBR dye from aqueous solution using both types of ZnO in the form of fine powders. The effects of pH, initial dye concentration, contact time and temperature of solution on the adsorption were studied. Langmuir, Temkin and Dubinin-Radushkevich (D-R) isotherm models were used to describe the adsorption of RBBR onto ZnO powders. The Langmuir and D-R isotherm models fit the equilibrium data better than the Temkin isotherm model. The monomolecular adsorption capacity of Z075 and Z300 was determined to be 190 and 345 mg g(-1) for RBBR, respectively. The Lagergren first-order, Ritchie second-order kinetic and intra-particle diffusion models were used for the adsorption of the dye onto ZnO powders. The Ritchie second-order model was suitable for describing the adsorption kinetics for the removal of RBBR front aqueous solution onto Z075 and Z300. Thermodynamic parameters, such as the Gibbs free energy (Delta G(#)), enthalpy (Delta H-#), entropy (Delta S-#) and equilibrium constant of activation (K-#) were calculated. These parameters showed that the adsorption process of RBBR onto Z075 and Z300 was an endothermic process of a chemical nature under the studied conditions. (C) 2008 Elsevier B.V. All rights reserved.
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    Antimicrobial activity of 4-subtituted-styrl-2-azetindinones
    (2005) Tan, Sema; Güner, Adar Vildan; Ergene, Aysun
    Bu çalışmada, daha önceden sentezleri yapılan 1-(substitutefenil)-4-(substiiuestril)-2-azetidinonlarin (3a-i) antimikrobiyal aktiviteleri incelenmiştir. Bütün bileşikler Gram () ve Gram (-) bakterilere ve mayaya karşı test edilmiştir. Aktivite, halkadaki substituentlerden önemli derecede etkilenmediği bulundu
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    Antimicrobial activity of 4-subtituted-styrl-2-azetindinones
    (Turkish Pharmacists Assoc, 2005) Tan, Sema; Güner, Vildan Adar; Ergene, Aysun
    In this study, antimicrobial activity of previously synthesized 1-(Substituted phenyl)-4-(substituted styryl)-2-azetidinones(3a-i) have been examined. All compounds have been tested against Gram(+) and Gram(-) bacteria and yeasts. It was found that activity is not significantly influenced by the substituents on the ring.
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    Antimicrobial Activity of Heracleum antasiaticum
    (Int Soc Horticultural Science, 2009) Ergene, Aysun; Tan, Sema; Mirici, Semra; Güler, P.; Yildirim, S.
    Heracleum L. (Apiaceae) includes more than 70 species in the world. This variety is representing 17 species in Turkey of which 7 species are endemic. Heracleum antasiaticum is an endemic species for Turkey. Heracleum antasiaticum has been shown to possess medicinal value, in particular, and antimicrobial activity. Heracleum antasiaticum was assayed for their in vitro antibacterial activities against eight pathogenic bacteria, and three yeast spp. The antimicrobial activity of the ethanol extract and water extract of Heracleum antasiaticum was investigated using an agar diffusion method. Ethanolic and aqueous extract of Heracleum antasiaticum differed significantly in their activity against the test microorganisms.
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    Characterization of lead-resistant river isolate Enterococcus faecalis and assessment of its multiple metal and antibiotic resistance
    (Springer, 2013) Aktan, Yasin; Tan, Sema; Icgen, Bulent
    Contamination of surface waters has a direct impact on the public health of entire communities. Microorganisms inhabiting contaminated surface waters have developed mechanisms of coping with a variety of toxic metals and drugs. Investigations were carried out to isolate and identify lead-resistant bacteria from the river KA +/- zA +/- lA +/- rmak along the city of KA +/- rA +/- kkale, Turkey. Of the 33 lead-resistant isolates, one isolate with a minimal inhibitory concentration of 1,200 mg L-1 was isolated and identified as Enterococcus faecalis by using biochemical tests and 16S rRNA sequencing. Lead-resistant E. faecalis isolate was found out to be resistant to other heavy metals like aluminum, lithium, barium, chromium, iron, silver, tin, nickel, zinc, and strontium and to drugs like amikacin, aztreonam, and gentamicin. E. faecalis harbored four plasmids with the molecular sizes of 1.58, 3.06, 22.76, and 28.95 kb. Plasmid profile analyses of cured derivatives revealed that the lead resistance ability of E. faecalis was still existing despite the elimination of all the plasmids. Moreover, the antibiotic resistance pattern of the cured derivatives did not demonstrate any change from the parental strain. Our findings indicated that the lead resistance genes of E. faecalis were located on the chromosomal DNA rather than the plasmid.
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    Cytogenetic damage in Allium cepa root meristems induced by Dursban 4 and Antracol WP 7 pesticides
    (Elsevier Science Bv, 2009) Ergene, Aysun; Tan, Sema; Yılmaz, F.; Topçu, Selim; Kaya, A.; Arslanoğlu, İlhan; Yalçın, E.
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    Cytotoxic effects of lead and mercury ions on root tip cells of Cicer arietinum L
    (Parlar Scientific Publications (P S P), 2009) Çavuşoğlu, Kültigin; Ergene, Aysun; Yalçın, Emine; Tan, Sema; Çavuşoğlu, Kürşat; Yapar, Kürşad
    In the present study, the cytotoxic effects of different concentrations of lead (Pb) and mercury (Hg) ions on Cicer arietinum L. root tip cells were investigated. For this aim, we used the aermination percentage, root length, weight gain, mitotic index (MI), the frequency of micronucleus (MN) and chromosomal aberrations (CAs) as indicators of cytotoxicity, and correlated these data with statistical parameters. Additionally to the cytogenetic analysis, lipid peroxidation and DNA analyses were performed in root tip meristems of C. arietinum treated with Hg and Pb. The seeds were divided into 5 groups as control, Hg and Pb treatment groups. They were treated with 10 and 50 ppm doses of Hg and Pb during 7 consecutive days. The initial and final weights of all the seeds were measured by sensitive balance to determine the effects of Pb and Hg on the weight gain. As a result, there was a significant alteration in germination percentage, root length, weight gain, MI, MN and CAs frequency depending on treatment dose in the seeds exposed to Hg and Pb when compared with the controls. Heavy metal exposure significantly reduced the germination percentage, root lenght and weight gain in all the treatment groups. But, it caused an increase in the MN and CAs formation. Pb and Hg metals caused various types of CAs at a rate which increased systematically with increased levels of Pb and Hg. It was also found that Pb and Hg metals have a mitodepressive action on mitosis, and the MI was decreased depending on the dose of Pb and Hg applied. Besides, 10 and 50 ppm concentrations of Pb and Hg significantly enhanced the lipid peroxidation and caused an increase in malondialdehyde (MDA) levels at both doses. The investigated parameters (except MDA, MN and CAs frequency) were higher in the seeds exposed to Pb than those treated with Hg. In other words, Hg had much more toxic effect on plant tissues than Pb. Moreover, it was observed that the yields of DNA in the seeds treated with Pb and Hg were lower than in the controls. Hence, DNA yields exposed to Pb and Hg were run ahead on agarose gel according to the control group. The results clearly indicate that Hg and Pb have important cytotoxic effects on the root tip cells, and C arietinum seeds are very sensitive and useful as biomarker for monitoring of these effects.
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    The cytotoxic, biochemical and physiological effects of Basudin 60 EM and Cupravit ob 21 pesticides on Allium cepa
    (Elsevier Science Bv, 2009) Tan, Sema; Ergene, Aysun; Topçu, Selim; Yılmaz, Funda; Kaya, A.; Arslanoğlu, İlhan; Cavuşoğlu, Kültiğin
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    Differences in structure, allergenic protein content and pectate lyase enzyme activity of some Cupressaceae pollen
    (Walter De Gruyter Gmbh, 2018) Sahin, Aydan Acar; Aslim, Belma; Tan, Sema; Alan, Senol; Pinar, Nur Munevver
    Objective: Cupressaceae pollen has commonly been reported to be an important aeroallergen and causal factor of spring, autumn and winter pollinosis in many countries. The aim of this study was to compare of the structure and allergenic protein content of Cupressus arizonica Greene., Cupressus sempervirens L. and Juniperus oxycedrus L. pollen in detail and contribute to Cupressaceae pollen allergen diagnosis and therapy studies in Turkey. Methods: The pollen structure were examined by LM and SEM. Pollen protein content was investigated by Bradford protein assay, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Western blot analysis and two-dimensional polyacrylamide gel electrophoresis (2DE PAGE), respectively. Pectate lyase (PL) enzyme activities were compared. Immunoblotting was carried out by using extracts of the three taxa pollen collected from Turkey. Results: All three taxa was found very similar in terms of pollen morphology however, intine thickness was prominently different. Cupressus arizonica pollen extracts showed the lowest PL activity. Five sera specific IgE of all allergic subjects showed reaction with only C. arizonica pollen extracts. Conclusions: As a conclusion, the pollen structure, protein function or protein structure and isoforms of allergens could affects allergenic properties of the pollen. This study also may help to improve the Cupressaceae pollen allergen diagnosis and therapy.
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    Genotoxic effects and enzymatic adaptations of Basudin 60 EM in Allium cepa
    (Parlar Scientific Publications (P S P), 2012) Ergene, Aysun; Arslanoglu, Ilhan; Yilmaz, Fadime; Tan, Sema; Yirtici, Umit
    Basudin 60 EM is commonly used in agricultural areas. Genotoxic effects of Basudin 60 EM (diazinon) were evaluated in the root meristem cells of Allium cepa. The roots of the plants were treated with 600, 1200 and 1800 ppm concentrations of Basudin 60 EM. Root tips after having grown to a certain length were stained according to aceto-orcein squash procedure. Metabolic variations in response to Basudin 60 EM toxicity was measured using physiological parameters and antioxidant enzymatic activities. A significant increase in SOD activity was observed in the leaves of Allium cepa, with the majority of Basudin 60 EM treatments. With increasing concentrations of Basudin 60 EM, CAT activity increased in leaves. An increase in the concentration of Basudin 60 EM increased GSH-Px activity in leaves. Basudin 60 EM exposure significantly reduced the carotenoid as well as chlorophyll a and b pigments in all treatment groups. Chromosomal aberrations, mitosis abnormalities, mitotic index and micronucleus assay of applied pesticides on Allium cepa roots were determined. All of the concentrations of Basudin 60 EM used in the present study significantly induced abnormalities, such as C-mitosis, chromosome stickiness, breaks, bridges, laggards, and multipolar cells compared to control. Also, Basudin 60 EM significantly decreased mitotic index for all concentrations.
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    Kinetic and equilibrium studies on the biosorption of Cl reactive orange 16 dye by immobilized Scenedesmus quadricauda
    (Asian Journal Of Chemistry, 2008) Tan, Sema; Ergene, Aysun; Ada, Kezban; Katircioglu, Hikmet
    The biosorption of commonly used reactive dye, reactive orange 16 (RO 16). from aqueous solutions by live (ILSq) and heat inactivated Scenedesmus quadricauda (IHISq) immobilized Scenedesmus quadricauda was studied in a batch system with respect to pH, temperature and biosorption time. The ILSq and IHISq exhibited the highest dye uptake capacity at 30 degrees C, the initial pH value of 2.0 and the initial dye concentration of 300 mg L(-1). At 300 mg L(-1) initial dye concentration in the batch system the adsorption capacity was determined as 88.4 mg g(-1) of dye biosorption for IHISq in 0.5 h. The adsorption capacity of ILSq was observed as 71.2 mg g(-1) in 0.5 h and 76.4 mg g(-1) and 82.8 mg g(-1) of dye biosorption within I and 3 h, respectively. The equilibrium concentration and the adsorption capacity at equilibrium were determined using four different sorption models i.e., Langmuir, Temkin, Flory-Huggins and Freundlich isotherm.
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    Metal removal of cyanobacterial exopolysaccharides by uronic acid content and monosaccharide composition
    (Elsevier Sci Ltd, 2014) Ozturk, Sahlan; Aslim, Belma; Suludere, Zekiye; Tan, Sema
    In the present study, chromium, cadmium and metal mixed (chromium + cadmium) removal and its association with exopolysaccharides and uronic acids production in Synechocystis sp. BAS0671 were investigated. It was investigated that BAS0671 showed different removal ability when exposed to each metal solely and mixed metal. EPS production by BAS0671 was increased following exposure to 15 and 35 ppm Cr(VI), Cd(II) and Cr(VI) + Cd(II). Monomer composition of EPS was changed after metal treatment. Uronic acid contents of metal treated cells were higher than control cells of each isolate. Also, glucuronic acid content and galactronic acid content of EPS correlated with uronic acid contents of cells. Scanning electron microscopy and energy dispersive X-ray spectroscopy analysis confirmed that a considerable amount of metals had precipitated on the cell surface. Fourier transform infrared spectrum analysis of EPSs indicated the presence of C-H and C-O group, which may serve as binding sites for divalent cations. (C) 2013 Elsevier Ltd. All rights reserved.
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    Production and characterization of biosurfactants produced by microorganisms isolated from milk factory wastewaters
    (Taylor & Francis Ltd, 2009) Yilmaz, F.; Ergene, Aysun; Yalçın, Emine; Tan, Sema
    Biosurfactants or surface-active compounds are produced by microorganisms. These molecules reduce the surface tension of both aqueous solutions and hydrocarbon mixtures. In this study, the isolation and identification of biosurfactant-producing microorganisms were assessed. The characterization of biosurfactant produced by microorganisms isolated from milk factory wastewaters was investigated. For this purpose, five different microorganisms were isolated and identified. In order to determine the biosurfactant production, the 'drop-collapse' method was applied and it was determined that only three species, Yarrowia lipolytica MFW5 (yeast), Micrococcus luteus MFW1 (cocci) and Burkholderia cepacia MFW2 (bacillus), were able to produce biosurfactant. Biosurfactants produced by Yarrowia lipolytica, Micrococcus luteus and Burkholderia cepacia were coded as BS-I, BS-II and BS-III, respectively. After the initial biosurfactant production and characterization studies were completed, isolates of these three species were incubated with whey wastewaters at 35 degrees C for 10 days for biosurfactant production. At the end of the incubation period, the biosurfactants were extracted and further characterized with biochemical analysis, FTIR spectra, haemolysis test, emulsification test and determination of the surface tension.
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    Removal and reduction of chromium by Pseudomonas spp. and their correlation to rhamnolipid production
    (Elsevier Science Bv, 2012) Ozturk, Sahlan; Kaya, Tayfun; Aslim, Belma; Tan, Sema
    Chromium removal and its association with rhamnolipid production in Pseudomonas spp. were investigated. Three Pseudomonas spp. isolates (P. aeruginosa 78, P. aeruginosa 99, and P. stutzeri T3) were investigated with regard to their exposure to 10 mg/L for chromium removal. P. aeruginosa 99 removed 16% and 20% more chromium than P. stutzeri T3 and P. aeruginosa 78 respectively. The reduction of Cr(VI) to Cr(III) by all the three isolates is more or less similar. P. aeruginosa 99, which removed higher chromium, also produced higher rhamnolipid (165 +/- 5 mg/mL). P. aeruginosa 78, which removed lower chromium, also produced lower rhamnolipid (126 +/- 3 mg/mL). Rhamnolipid production by P. aeruginosa 78 and P. aeruginosa 99 was increased in its exposure to 10 mg/L chromium. In the present study, results showed that rhamnolipid might play a role in chromium removal by three Pseudomonas spp. isolates. (C) 2012 Elsevier B.V. All rights reserved.
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    Removal of Remazol Brilliant Blue R dye from aqueous solutions by adsorption onto immobilized Scenedesmus quadricauda: Equilibrium and kinetic modeling studies
    (Elsevier Science Bv, 2009) Ergene, Aysun; Ada, Kezban; Tan, Sema; Katircioglu, Hikmet
    The green algae Scenedesnnus quadricauda was immobilized in alginate gel beads. The immobilized active (IASq) and heat inactivated S. quadricauda (IHISq) were used for the removal of Remazol Brilliant Blue R (Cl 61200, Reactive Blue 19, RBBR) from aqueous solutions in the concentration range 25-200 mg L(-1). At 150 mg L(-1) initial dye concentration the IASq and IHISq exhibited the highest dye uptake capacity at 30 degrees C, at the initial pH value of 2.0. At the same initial dye concentration in the batch system the adsorption capacity was determined for IASq as 44.2: 44.9 and 45.7 mg g(-1) in 30. 60 and 300 min, respectively. After 300 min the adsorption capacity hardly changed during the adsorption time. The IHISq of adsorption capacity was observed as 47.6; 47.8 and 48.3 mg g(-1) in 30, 60 and 300 min. respectively. After 300 min the adsorption capacity was not changed for 24 h. The Langmuir, Freundlich, Temkin, Dubinin-Radushkevich and Flory-Huggins isotherm models were used to fit the equilibrium biosorption data. The Langmuir, Freundlich and Dubinin-Radushkevich equations have better coefficients than Temkin and Flory-Huggins equation describing the RBBR dye adsorption onto IASq and IHISq. The monomolecular biosorption capacity of the biomass was found to be 68 and 95.2 mg g(-1) for IASq and IHISq, respectively. From the Dubinin-Radushkevich model. the mean free energy was calculated as 6.42-7.15 kJ mol(-1) for IASq and IHISq, indicating that the biosorption of dye was taken place in physical adsorption reactions. The experimental data were also tested in terms of kinetic characteristics and it was determined that the biosorption process of dye was well explained with pseudo-second-order kinetics. (C) 2009 Elsevier B.V. All rights reserved.