Person: ÇELİK, ÖZGE
Loading...
Email Address
Birth Date
Research Projects
Organizational Units
Job Title
Prof.Dr.
Last Name
ÇELİK
First Name
ÖZGE
Name
14 results
Search Results
Now showing 1 - 10 of 14
Publication Open Access Otokrin büyüme hormonu (BH) sinyalinin curcumin'e karşı direnç mekanizmasındaki rolünün endoplazmik retikulum stres ve otofajik yolaklara bağlı olarak MDA-MB-231 ve T47D meme kanseri hücrelerinde irdelenmesi(İstanbul Kültür Üniversitesi / Fen Bilimleri Enstitüsü / Moleküler Biyoloji ve Genetik Anabilim Dalı / Moleküler Biyoloji ve Genetik Bilim Dalı, 2019) Bulut, Derya; ÇELİK, ÖZGE; Gürkan, Ajda ÇokerMeme kanseri kadınlarda kanser kaynaklı ölümler arasında ikinci sırada yer alan ve büyüme faktörleri, hormonal düzenleme ile gelişimi seyreden bir kanserdir. Yakın zamanda, büyüme hormonunun (BH) meme kanseri hücrelerinde anlatımının arttırılmasının hücre büyüme, invazyon-metastaz ve ilaç direncine neden olduğu tespit edilmiştir. BH kaynaklı ilaç direncinde bitkisel kökenli curcuminin etkisi zamana ve doza bağlı olarak gösterilmiştir. Ancak curcuminin terapötik potansiyelinin arttırılması ve apoptotik etkinliğinin moleküler mekanizmasında ER stres ve otofajinin rolü bilinmemektedir. Bu tez ile amacımız MDA-MB-231 ve T47D doğal tip ve BH+ meme kanseri hücreleri üzerine zamana bağlı curcuminin etkisinin yanında otolizozom inhibitörü olan bafilomisinle kombine tedavisinde apoptotik etkinliğinin ER ve otofaji yolakları göz önünde bulundurularak irdelenmiştir. Zamana bağlı curcumin uygulamasının otokrin BH sinyali aracılı direnç mekanizmasının otofajik ve ER stres anahtar molekülleri üzerinden gerçekleştirdiği MDA-MB-231 ve T47D meme kanseri hücrelerinde gösterilmiştir. Curcumin direncinin kırılmasına bağlı terapötik etkinliğin irdelenmesi için bafilomisin ile curcuminin beraber uygulamasının ER stres anahtar moleküllerinin anlatımını baskılayarak ve otofaji sürecinde geç aşama olan otolizozomu engelleyerek apoptotik hücre ölümünü indüklediği MDA-MB-231 ve T47D meme kanseri hücrelerinde belirlenmiştir. Böylece bu tez ile ilk defa otokrin BH sinyali kaynaklı curcumin ilaç direnç mekanizmasının moleküler mekanizmasında ER stres ve otofajinin rolünün aydınlatılması yanında curcuminle beraber bafilomisin uygulamasının curcumine bağlı apoptotik hücre ölümünü indüklediği MDA-MB-231 ve T47D hücrelerinde tespit edilmiştir.Publication Embargo Micropropagation of Anthurium adreanum from leaf explants(Department of Molecular Biology and Genetics, Faculty of Science and Letters, Istanbul Kultur University, Ataköy, Istanbul, Turkey, 2009) ATAK, ÇİMEN; ÇELİK, ÖZGE; 113987; 6653Anthurium propagation by tissue culture techniques appears as an alternative to increase the production. Plant regeneration of Anthurium andraeanum cultivars “Arizona” and “Sumi” (Anthura) has been achieved through adventitious shoots formation from callus. The leaf explants were used for the propagation by indirect organogenesis. Callus induction medium consisted of half-strength MS basal salt with 0.6 mg/l 2,4-D, 1 mg/l BA. Shoot regeneration medium consisted of modified halfstrength MS salts with NH4NO3 lowered to 250 mg/l, 0.1 mg/l 2, 4-D and 1 mg/l BA. Rooting medium was (modified half-strength MS salts) supplemented with 1mg/l IBA and 0.04%active charcoals. The callus induction rate of Arizona variety was higher as compared to Sumi variety and this increase was found significant. The number of shoots per explants for Arizona variety also significantly increased as compared to Sumi variety. Arizona and Sumi root percentages were high and these percentages were 98% and 95% respectively. The results showed that Arizona variety had different responses as compared to Sumi variety for callus induction and the number of shoots per explants. Shoot multiplication for two varieties increased in the multiplication stages and this increase in number of shoots per explants were found important (p<0.05).Publication Embargo Micropropagation of Anthurium spp(InTech Open Science, 2012) ATAK, ÇİMEN; ÇELİK, ÖZGE; 113987; 6653Publication Embargo Applications of Ionizing Radiation in Mutation Breeding(InTech, 2017-05) ATAK, ÇİMEN; ÇELİK, ÖZGE; 113987; 6653As a predicted result of increasing population worldwide, improvements in the breeding strategies in agriculture are valued as mandatory. The natural resources are limited, and due to the natural disasters like sudden and severe abiotic stress factors, excessive floods, etc., the production capacities are changed per year. In contrast, the yield potential should be significantly increased to cope with this problem. Despite rich genetic diversity, manipulation of the cultivars through alternative techniques such as mutation breeding becomes important. Radiation is proven as an effective method as a unique method to increase the genetic variability of the species. Gamma radiation is the most preferred physical mutagen by plant breeders. Several mutant varieties have been successfully introduced into commercial production by this method. Combinational use of in vitro tissue culture and mutation breeding methods makes a significant contribution to improve new crops. Large populations and the target mutations can be easily screened and identified by new methods. Marker assisted selection and advanced techniques such as microarray, next generation sequencing methods to detect a specific mutant in a large population will help to the plant breeders to use ionizing radiation efficiently in breeding programs.Publication Embargo Random amplified polymorphic DNA analysis of salt-tolerant tobacco mutants generated by gamma radiation(Funpec-Editora, Rua Floriano Peixoto 2444, Alto Da Boa Vista, Ribeirao Preto, Sp 00000, Brazil, 2015) ATAK, ÇİMEN; ÇELİK, ÖZGE; 113987; 6653Salinity is one of the major problems limiting the yield of agricultural products. Radiation mutagenesis is used to improve salt-tolerant mutant plants. In this study, we aimed to improve salt-tolerant mutants of two oriental tobacco varieties. One thousand seeds of each variety (M-0) were irradiated with 100, 200, 300, and 400 Gy gamma rays by Cs-137 gamma. In the M-1 generation, 2999 single plants were harvested. The next season, these seeds were bulked and planted to obtain M-2 progeny. The seeds of 1900 M-2 plants were picked separately. Salinity tolerance was tested in the M-3 generation. Among M-3 plantlets, 10 salt-tolerant tobacco mutants were selected. According to the results of the selection studies, 100- and 200-Gy gamma radiation doses were the effective doses to obtain the desired mutants. Glutathione reductase enzyme activities of salt-tolerant tobacco mutants were determined biochemically as a stress-tolerance marker. The differences between control and salt-tolerant mutants belonging to the Akhisar 97 and Izmir Ozbas tobacco varieties were evaluated by random amplified polymorphic DNA analysis. The total polymorphism rate was 73.91%.Publication Embargo 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; 109872The 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.Publication Embargo Evaluation of Proline Accumulation and Delta(1)-pyrroline-5-carboxylate Synthetase (P5CS) Gene Expression during Salinity Stress in Two Soybean (Glycine max L. Merr.) Varieties(Hard, Post-Office Box, 10-718 Olsztyn 5, Poland, 2012) ATAK, ÇİMEN; ÇELİK, ÖZGE; 113987; 6653The aim of our study was to compare the effects of salt stress in two soybean (Glycine max L. Merr) varieties. Two soybean genotypes (Ataem-7 and Ustun-1) were grown under 0, 50, 100, and 150 mM NaCl treatments, and the leaves were harvested for lipid peroxidation analyses, proline content and P5CS gene expression levels. According to the results of lipid peroxidation analysis, Ataem-7 variety was found to be more sensitive than Ustun-1 variety for NaCl stress. Proline is an important osmolyte accumulated under environmental stresses. As a response to salinity, we determined their proline levels. Proline accumulation in Ataem-7 variety increased 1:39 fold in accordance with Ustun-1 variety at 150 mM NaCl treatment. Glycine max Delta(1)-pyrroline-5-carboxylate synthetase (GmP5CS) gene expression levels under 50, 100 and 150 mM NaCl stress were determined. When the GmP5CS gene expression level was gradually increased in Ustun-1 variety, the highest gene expression level for Ataem-7 was determined at 100 mM NaCl. The GmP5CS gene expression in Ustun-1 at 150 mM NaCl increased 2.93 fold compared with 100 mM treatment. When we evaluate the relation between proline accumulation and expression levels of GmP5CS gene, it is obvious that accumulations of proline in two soybean varieties are under control of different mechanisms in the presence of salinity.Publication Embargo Enzymatic and non-enzymatic comparison of two different industrial tomato (Solanum lycopersicum) varieties against drought stress(Springer, 233 Spring St, New York, Ny 10013 USA, 2017-08-02) AYAN, ALP; ATAK, ÇİMEN; ÇELİK, ÖZGE; 113987; 185510; 6653Background: The aim of this study is to compare the tolerance mechanisms of two industrial tomato varieties (X5671R and 5MX12956) under drought stress. 14 days-old tomato seedlings were subjected to 7 days-long drought stress by withholding irrigation. The effects of stress were determined by enzymatic and non-enzymatic parameters. The physiological damages were evaluated via lipid peroxidation ratio, total protein content, relative water content, chlorophyll content and proline accumulation. Enzymatic responses were determined by biochemical analysis and electrophoresis of SOD, APX, POX and CAT enzymes. Results: Relative water contents of X5671R and 5MX12956 varieties at 7th day of drought were decreased to 8.4 and 12.2%, respectively. Applied drought decreased all photosynthetic pigments of X5671R and 5MX12956 varieties during the treatment period significantly comparing to the Day 0 as the control. Total protein content, lipid peroxidation and proline accumulation presented increased values in both varieties in accordance with the increasing stress intensity. According to lipid peroxidation analysis, 5MX12956 tomato variety was found more drought sensitive than X5671R variety. Antioxidative enzyme activities showed increases in both varieties as a response to drought stress, although CAT and APX activities presented decrease on the 7th day of applied stress. 7 days long drought stress differentially altered POX, APX and SOD isozyme patterns. Same POX bands were observed in both varieties with different band intensities. Conclusions: However, main isozyme pattern differences were obtained for SOD and APX. APX1, Fe-SOD and Cu/Zn-SOD2 isozyme bands should be evaluated to define their main role in the tolerance mechanism of both tomato varieties.Publication Open Access Identification of the antioxidant defense genes which may provide enhanced salt tolerance in Oryza sativa L.(2019-06) Çakır, Bilgin Candar; ATAK, ÇİMEN; ÇELİK, ÖZGEAntioxidative mechanisms are important to protect cells from the hazardous effects of reactive oxygen species (ROS). Salt stress is one of the environmental stress factors that leads to accumulation of ROS at toxic levels. In this study, we analyzed the responses of two rice (Oryza sativa L.) cultivars against NaCl stress at enzymatic and transcriptional levels. In 14day-old-seedlings, different antioxidant enzyme activities were observed. These findings were also supported by transcriptional analyses of the responsible genes. According to the results, Cyt-APX, CAT A, Cyt-GR1 and proline metabolism-related genes were differentially expressed between two rice varieties under different salt concentrations. Their regulational differences cause different salt sensitivities of the varieties. By this study, we provided an insight into understanding of the correlation between antioxidant defence genes and ROS enzymes under salt stress.Publication Embargo Genetic Similarity between Ottoman Strawberry and the Other Early-Period Strawberry Cultivars Assessed by RAPD Markers(Austin Publishing Group, 2017) Doğan, H.; Akdaş, E. Y.; Uslu, Y. B.; Zengin, U.; ÇELİK, ÖZGE; 113987Most of the local strawberry (Fragaria x ananassa Duchenese) cultivars of Turkey are not phylogenetically classified. This present study, which aimed discriminating the genetical relationships between the Ottoman strawberry cultivar and other early-period strawberry cultivars planted in Istanbul and Karadeniz Ereğli regions of Turkey, is the first on this field. Seven strawberry cultivars were analyzed by using RAPD. 10 random primers carried out DNA fingerprinting analyses of these cultivars. The average polymorphism rate was determined as 87.1%. The most polymorphic primer was OPH01 which produced 13 bands. The cluster dendrogram presented that the similarity coefficients were between range of 0.03 and 0.73. Ottoman cultivar showed higher similarity with Tüylü more than Kara cultivar which is reported as the mother cultivar. RAPD method was sufficient to assess the phylogenetic relationship between Ottoman cultivar and other early-period strawberry cultivars. The data of this study brought forward the necessity of further genetic analysis to prove the phylogenetic relationship among Tüylü and Ottoman cultivars.