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Now showing 1 - 10 of 62
  • PublicationMetadata only
    Bir Kalpain İnhibitörü Olan AK295’in Nöroprotektif Etkilerinin Deneysel Spinal Kord Travması Modelinde İncelenmesi
    (Türk Nöroşirurji Derneği, XIX. Bilimsel Kongresi, 2005) Kaya, M.; Antar, V.; Kelten, B.; Akdemir, O.; Karaoğlan, A.; Soy, O.; Çolak, A.; ÇELİK, ÖZGE; 113987
  • PublicationMetadata only
    Evaluation of Superoxide dismutase loaded microspheres
    (2007-01-11) Akbuğa, Fatma Jülide; ÇELİK, ÖZGE; 113987; 11241
  • PublicationMetadata only
    Effects of Magnetic Field on Activity of Superoxide Dismutase and Catalase in Glycine max (L.) Merr. Roots
    (Hard, Post-Office Box, 10-718 Olsztyn 5, Poland, 2009) Büyükuslu, N.; Rzakoulieva, A.; ÇELİK, ÖZGE; TR113987
    Under a magnetic field the activities of superoxide dismutase (SOD) in vitro and in vivo and accompanying activities of catalase activity in vivo were investigated in soybean roots. In plant cells a magnetic field creates a stress condition as other environmental stress factors do. To respond to the stress conditions, the occurred reactive oxygen species are scavenged by defense systems. In this study, two enzymes of the defense system, SOD and catalase activities were investigated under magnetic field. Enzyme and soybean seeds exposed to a magnetic field for a period of 2.2, 19.8. and 33s at the magnetic flux of 2.9-4.6 mT. SOD activities data were compared with magnetized enzyme and soybean roots. While the absorbance values of enzyme that passed through the magnetic field with a period of 19.8s for 24 hours were measured and SOD activity was significantly increased. At the same time, magnetic field SOD activity of the soybean roots was increased 21.18% relative to control (P<0.05). After soybean seeds were treated by various magnetic fields and time periods, the activities of superoxide dismutase and catalase were significantly increased (P<0.05) during germination. At the 19.8s for 72 hours, SOD and catalase activities were increased 21.15% and 15.20% relative to control, respectively Thus, it is indicated that the function of defense enzymes in seedlings was intensified due to the treatment of magnetic field. The increases of magnetic field exposure times do not cause linear increases in enzyme activities in vitro and in vivo studies.
  • PublicationEmbargo
    The effect of magnetic field on the activity of superoxide dismutase
    (Haliç University, Faculty of Arts and Sciences, Department of Molecular Biology and Genetics, Fındıkzade 34280, İstanbul-Turkey, 2006) Büyükuslu, Nihal; ATAK, ÇİMEN; ÇELİK, ÖZGE; 6653; 113987; 109872
    The effects of magnetic field on superoxide dismutase activity were investigated. All living systems are affected by magnetic field and electromagnetic field in a way of their response systems. Since magnetic field has an impact on biochemical reactions that involve more than one unpaired electron, in our study SOD activity, one of the enzyme responsible for antioxidant system, was measured under magnetic fields using an apparatus explained at material methods. There has been a significant increase of SOD activity when passed 0, 1, 9 and 15 times at 2.9-4.6 mT magnetic field density for 0, 2.2, 19.8 and 33.0 seconds respectively.
  • PublicationEmbargo
    Response of soybean plants to gamma radiation: Biochemical analyses and expression patterns of trichome development
    (2014) Suludere, Zekiye; ATAK, ÇİMEN; ÇELİK, ÖZGE; 6653; 113987; 4019
    This is the first report on soybean with the aim to show the effects of gamma radiation on trichome metabolim. Soybean seeds were subjected to 300 Gy gamma radiation at a dose rate of 10 Gy/min using a Cs-137 gamma source. The photosynthetic pigment, total protein content and ascorbate peroxidase activity were studied. The results showed that the chlorophyll a content was decreased by 80% on day 14 and by 77% on day 21 of irradiation. The chlorophyll b content was reduced by 58.6% and 62.06% on day 14 and 21 after irradiation, respectively. The total carotenoid concentration was reduced by 81.14% on the 14th day after irradiation and by 91% on the 21st day of irradiation, compared to control. The total protein concentration was found to have decreased significantly at 14 and 21 day after treatment. High level of ascorbate peroxidase (APX) activity was recorded in the leaves developed from irradiated soybean seeds, compared to the non-irradiated group. The trichome densities were 6.76 fold increased at 21 day of irradiation, while the stomatal densities were decreased, compared to control. We also performed a qRT-PCR analysis to detect the transcription levels of the soybean trichome developmental genes. The GL2 and CPC genes were up-regulated (P≤0.05). The results of this study pointed out that the CPC transcription factor has to be study in further studies to provide an insight on its exact role in regulation of trichome development in soybean under radiation stress.
  • PublicationMetadata only
    Development of Superoxide Dismutase Loaded Microspheres
    (2007-03-27) Akbuğa, Fatma Jülide; ÇELİK, ÖZGE; 113987; 11241
  • PublicationMetadata only
    Molecular Marker Analysis of Salt Tolerant Soybean Mutants
    (Springer, 233 Spring Street, New York, Ny 10013, United States, 2014-08) Candar, Bilgin; ATAK, ÇİMEN; ÇELİK, ÖZGE; 113987; 195745; 6653
  • PublicationMetadata only
    Molecular marker analyses of salt tolerant soybean mutants
    (2014-08) Çakır, Bilgin Candar; ATAK, ÇİMEN; ÇELİK, ÖZGE
  • PublicationMetadata only
    The Effect Of Salt Stress On Antioxidative Enzymes And Proline Content Of Two Turkish Tobacco Varieties
    (Tubitak Scientific & Technical Research Council Turkey, Ataturk Bulvari No 221, Kavaklidere, Ankara, 00000, Turkey, 2012) ATAK, ÇİMEN; ÇELİK, ÖZGE; 6653; 113987
    The aim of this study was to compare the salinity tolerances of 2 oriental tobacco varieties (Izmir Ozbas and Akhisar 97). Salinity stress experiments were performed under both in vitro and in vivo conditions. Seedlings of each variety were subjected to 0, 50, 100, 150, 200, 250, 300, and 350 mM NaCl. Photosynthetic pigment levels, lipid peroxidation rate, total protein content, antioxidant enzyme activities, and proline concentrations were determined for seedlings treated with salt for 14 days. The Akhisar 97 variety was found to be more sensitive to salinity stress than the Izmir Ozbas variety. Although proline is thought to accumulate in salt-tolerant plants, we found a negative correlation between salinity tolerance and proline accumulation in the plants. According to biochemical analyses, there were no differences in SOD, APX, GPX, or CAT activity levels between the 2 varieties, either in vivo or in vitro. However, differences in glutathione reductase (GR) activity between control plants and plants under NaCl stress were statistically significant in both varieties, both in vitro and in vivo. Our results support the hypothesis that GR is a key element in the evaluation of salinity tolerance of tobacco varieties.
  • PublicationEmbargo
    Stimulation of Rapid Regeneration by a Magnetic Field in Paulownia Node Cultures
    (2008) Rzakulieva, Aitekin; ATAK, ÇİMEN; ÇELİK, ÖZGE; 113987; 6653
    In this study, the aim was to determine the effect of magnetic fields on regeneration of Paulownia node cultures. Paulownia tomentosa node cultures were used to generate explants and these explants were passed through a 2.9- 4.6-mT magnetic flux density 1 and 9 times at 2.2 and 19.8 seconds, respectively. Chlorophyll quantities, total RNA concentrations of shoots and shoot formation rates from control and treated explants were determined. While the shoot formation rate was 61.9% in the control group, this rate was increased in magnetic field experiments and shoot formation was 82.5% in the explants that were exposed to a magnetic field for a 2.2 second period. However, the regeneration percentage of the explants exposed to a MF for a period of 19.8 s was 45%. Chlorophyll a, chlorophyll b and total chlorophyll contents of the 2.2 s group were increased in comparison to the control group. Total RNA concentrations of seedlings regenerated from treatment explants treated for 2.2 seconds significantly increased in comparison to the control (p<0.05). Our experiments show that the exposure duration to MFs is an important factor for plant tissue. MFs may be used in in vitro regeneration studies rapid and for a short time.