Fen Edebiyat Fakültesi / Faculty of Letters and Science
Permanent URI for this collectionhttps://hdl.handle.net/11727/1396
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Item Üniversiteler için Türk dili ders kitabı(2008) Guzel, Abdurrahman; Demir, Nurettin; Celik, Yakup; Demir, Ahmet; Atabey, Ibrahim; Aslan Demir, Sema; Kuzu, Tulay; Ay, ArifItem Moderate level of toxic boron causes differential regulation of microRNAs related to jasmonate and ethylene metabolisms in Arabidopsis thaliana(2019) Kayihan, Doga Selin; Kayihan, Ceyhun; Ciftci, Yelda Ozden; 0000-0003-1684-4147; Q-4515-2016Earlier our colleagues detected that the genes related to jasmonate (JA), ethylene, and cell wall modification were significantly regulated under boron (B) toxicity in wheat. Determination of regulation mechanisms of these novel genes under B toxicity is very important in Arabidopsis thaliana as a model plant. As key regulators, the microRNAs (miRNAs) regulate gene expression at the posttranscriptional level and respond to numerous abiotic stresses in plants. In this study, expression levels of miRNAs such as miR159, miR172, miR319, and miR394 targeting JA and ethylene-related transcription factors and also miR397 targeting laccase were determined in Arabidopsis thaliana under toxic B conditions. Stem-loop quantitative reverse transcription polymerase chain reaction was used to amplify mature miRNAs for expression analyses. Expression levels of miRNAs targeting transcription factors related to JA and ethylene metabolisms were induced remarkably in moderate B toxicity (condition 1B) but not in severe B toxicity (condition 3B). Most remarkable regulations were obtained in miR172 and miR319 in Arabidopsis thaliana. Expression level of miR397 did not remarkably change under B toxicity, indicating a lack of posttranscriptional regulation of laccase related to cell wall modification. Moreover, miRNAs targeting transcription factors related to JA and ethylene metabolisms might be oxidative stress-adaptive responses of Arabidopsis to B toxicity.Item Assessment of the effects of radiofrequency radiation on human colon epithelium cells(2019) Tomruk, A.; Terzi, Y.K.; Guler, Ozturk G.; 0000-0001-5612-9696; 31023054; B-4372-2018OBJECTIVES: The aim of the study was to investigate the possible effects of radiofrequency radiation (RFR) at different frequencies for different exposure durations on caspase-dependent apoptosis pathways in human colon adenocarcinoma (HT-29). METHODS: HT-29 cells were exposed to 1800 MHz; 2100 MHz and 2600 MHz RFR for 3 h cont., 6 h int. and 6 h cont.. Cell viability measurements were performed by Trypan Blue exclusion assay and the gene expressions of CASP8, CASP9, CASP3 and CASP12 were analyzed using qRT-PCR. RESULTS: Exposure to 2100 MHz RFR for all 3 durations of exposures was more effective for the ratio of the number of viable HT-29 cells w.r.t 1800 MHz RFR and 2600 MHz RFR exposures. After 2100 MHz RFR exposure, caspase activation increased significantly (for 3h cont. and 6 h int. exposures CASP8 and CASP9 levels; for 6 h cont. exposure CASP3 levels) (p < 0.05). Exposures to both 1800 MHz and 2600 MHz RFR for 3 different exposure durations did not change the activation of caspases we analyzed in this study (p > 0.05). CONCLUSION: Decreases in the cell viability of HT-29 cells for certain frequencies and also durations are consistent with signifi cant increases in caspase activations. The results of caspase activation after 1800 MHz or 2600 MHz RFR exposures can be interpreted as the activation of different types of cell death pathway by caspase signaling cascades (Fig. 15, Ref. 56).Item Changing Cultural Practices, Self-Identifications and Gender Roles of Kurdish and Turkish Catering and Retail Business Owners in London(2019) Karan, Olgu; 0000-0002-1581-1987; M-9255-2016This paper focuses on the changing cultural practices, self-identifications, and gender roles of Kurdish and Turkish (KT) communities in London. It explores the research question of how the occupational shift from industrial waged labour to self-employment affects the cultural practices, gender roles and identity construction processes of Kurdish and Turkish business owners in catering and retail sectors in London. Depending on a field study consisting of 40 in-depth interviews, this paper draws the conclusions that identification of shared interests and interest alignment in Britain promote bonds of solidarity, new forms of ethnic attachment, which are not salient in the home country and may be helpful to overcome various problems of the KT communities in London.Item FUNCTIONAL CHARACTERIZATION OF SPERMINE FAMILY TRANSPORTER caf5(+) IN Schizosaccharomyces pombe (Lindner)(2019) Ors Gevrekci, AslihanPolyamines are well conserved polycationic molecules that are known to interact with nucleic acids and contribute to multiple functions including cell cycle and stress response. The transport of polyamines in and out of the cell is driven by polyamine transporters that play a significant role in polyamine homeostasis. Schizosaccharomyces pombe (Lindner) caf5(+) gene codes for a spermine family transporter that is yet to be characterized functionally. This study aims to understand the contribution of caf5(+) on different processes previously associated with polyamines, by reverse genetics. Deletion mutants of caf5(+), which are viable in normal conditions, were scanned for multiple cellular processes. The results showed that caf5(+) deletion caused shorter cell length and slightly faster growth rate at the optimum conditions. caf5. cells also showed sensitivity to high doses of UV irradiation, while no sensitivity was observed against osmotic stress or another DNA damaging agent hydroxyurea. The mutants could successfully go through different phases of mitosis and meiosis as observed by DNA and septum staining. In summary, caf5(+) gene is involved in normal growth and cell cycle progression, as well as stress response upon UV irradiation.Item A novel homozygous nonsense mutation in CAST associated with PLACK syndrome(2019) Temel, Sehime Gulsun; Karakas, B.; Seker, U.; Turkgenc, B.; Zorlu, O.; Saricaoglu, H.; Ogur, C.; Kutuk, O.; Kelsell, D. P.; Yakicier, M. C.; 0000-0001-9854-7220; 31392520; AAH-1671-2019Peeling skin syndrome is a heterogeneous group of rare disorders. Peeling skin, leukonychia, acral punctate keratoses, cheilitis and knuckle pads (PLACK syndrome, OMIM616295) is a newly described form of PSS with an autosomal recessive mode of inheritance. We report a 5.5-year-old boy with features of PLACK syndrome. Additionally, he had mild cerebral atrophy and mild muscle involvements. Whole exome sequencing was performed in genomic DNA of this individual and subsequent analysis revealed a homozygous c.544G > T (p.Glu182*) nonsense mutation in the CAST gene encoding calpastatin. Sanger sequencing confirmed this variant and demonstrated that his affected aunt was also homozygous. Real-time qRT-PCR and immunoblot analysis showed reduced calpastatin expression in skin fibroblasts derived from both affected individuals compared to heterozygous family members. In vitro calpastatin activity assays also showed decreased activity in affected individuals. This study further supports a key role for calpastatin in the tight regulation of proteolytic pathways within the skin.Item Composite clinoptilolite/PCL-PEG-PCL scaffolds for bone regeneration: In vitro and in vivo evaluation(2019) Pazarceviren, Ahmet Engin; Dikmen, Tayfun; Altunbas, Korhan; Yaprakci, Volkan; Erdemli, Ozge; Keskin, Dilek; Tezcaner, Aysen; 0000-0001-8606-8863; 31475790; AAG-3927-2019In this study, clinoptilolite (CLN) was employed as a reinforcement in a polymer-based composite scaffold in bone tissue engineering and evaluated in vivo for the first time. Highly porous, mechanically stable, and osteogenic CLN/PCL-PEG-PCL (CLN/PCEC) scaffolds were fabricated with modified particulate leaching/compression molding technique with varying CLN contents. We hypothesized that CLN reinforcement in a composite scaffold will improve bone regeneration and promote repair. Therefore, the scaffolds were analyzed for compressive strength, biodegradation, biocompatibility, and induction of osteogenic differentiation in vitro. CLN inclusion in PC-10 (10% w/w) and PC-20 (20% w/w) scaffolds revealed 54.7% and 53.4% porosity, higher dry (0.62 and 0.76 MPa), and wet (0.37 and 0.45 MPa) compressive strength, greater cellular adhesion, alkaline phosphatase activity (2.20 and 2.82 mg/g(DNA)/min), and intracellular calcium concentration (122.44 and 243.24 g Ca/mg(DNA)). The scaffolds were evaluated in a unicortical bone defect at anterior aspect of proximal tibia of adult rabbits 4 and 8 weeks postimplantation. Similar to in vitro results, CLN-containing scaffolds led to efficient regeneration of bone in a dose-dependent manner. PC-20 demonstrated highest quality of bone union, cortex development, and bone-scaffold interaction at the defect site. Therefore, higher CLN content in PC-20 permitted robust remodeling whereas pure PCEC (PC-0) scaffolds displayed fibrous tissue formation. Consequently, CLN was proven to be a potent reinforcement in terms of promoting mechanical, physical, and biological properties of polymer-based scaffolds in a more economical, easy-to-handle, and reproducible approach.Item Regulation of boron toxicity responses via glutathione-dependent detoxification pathways at biochemical and molecular levels in Arabidopsis thaliana(2019) Kayihan, Doga Selin; Kayihan, Ceyhun; Ciftci, Yelda Ozden; 0000-0002-9799-3648; Y-6244-2018The fine-tuned regulation of the Halliwell-Asada cycle (ascorbate-glutathione pathway) in Arabidopsis thaliana under boron (B) toxicity was shown in our previous report. In this study, we investigated the expression levels of some members of the glutathione S-transferase (GST) superfamily, such as phi (GSTF2, GSTF6, GSTF7, and GSTF8), tau (GSTU19), and zeta (GSTZ1) classes in Arabidopsis thaliana that were exposed to 1 mM boric acid (1B) and 3 mM boric acid (3B). Additionally, the expression levels of genes for glutathione (GSH) and phytochelatin biosynthesis as well as miR169 and miR156 were evaluated in Arabidopsis thaliana exposed to 1B and 3B. Moreover, changes in the levels of total GST activity; GSH; and total, protein-bound, and nonprotein thiols were spectrophotometrically determined. GSH levels and nonprotein thiol content did not change significantly following both B-toxicity conditions. Expression levels of GSH1 and GSH2 stayed stable under 1B toxicity; however, GSH1 expression increased significantly under 3B conditions in Arabidopsis thaliana. The expression levels of four genes from phi class members of GST were not dramatically changed under B-toxicity conditions. However, the transcript levels of miR169, ATGSTU19, and ATGSTZ1 were significantly increased after 1B and 3B exposure. These GST genes may have a role in the dramatic increase of total GST activity under toxic B. To the best of our knowledge, this is the first report displaying an integrative view of high-B-induced regulation of GSH-dependent enzymatic machinery at different biological organization levels in Arabidopsis thaliana.Item beta-Adrenoreceptor antagonists reduce cancer cell proliferation, invasion, and migration(2014) Iseri, Ozlem Darcansoy; Sahin, Feride Iffet; Terzi, Yunus Kasim; Yurtcu, Erkan; Erdem, S. Remzi; Sarialioglu, Faik; 25026350Context: Propranolol, atenolol, and ICI118,551 are non-selective beta-adrenergic receptor (AR), beta(1)-AR, and beta(2)-AR antagonists, respectively. Objective: We investigated the efficacy of propranolol, atenolol, and ICI118,551 on proliferation, migration, and invasion of non-stimulated breast (MCF7), colon (HT-29), and hepatocellular (HepG2) cancer cells. Materials and methods: beta-AR expression profiling of cells was performed by real time PCR. Cell proliferation was determined by MTT. Boyden chamber and scratch assays were performed to evaluate invasion and migration. Results and discussion: All cell lines expressed beta-ARs. ICI118,551 was the most cytotoxic, whereas atenolol was the least effective beta-AR antagonist for 24, 48, and 72 h. Cell invasion was inhibited by ICI118,551 (45, 46, and 50% for MCF7, HT29, and HepG2, respectively) and propranolol (72, 65, and 90% for MCF7, HT29, and HepG2, respectively). Propranolol, atenolol, and ICI118,551 reduced migration of MCF7, HT-29, and HepG2 cells to varying extents depending on the application concentration and duration. Propranolol and atenolol reduced migration of MCF7 and HT-29 in a concentration-dependent manner, whereas migration of these cells decreased after 48 and 72 h of ICI118,551 applications. Conclusion: Beta(2)-AR antagonist seemed to be the most cytotoxic beta-blocker on non-stimulated cancer cells. Propranolol and ICI118,551 were more effective than atenolol in inhibiting invasion and migration of non-stimulated MCF7 and HT-29 cells; ICI118,551 being the most potent. Concordantly, beta(2)-selective blockage seemed to be more effective for non-stimulated cells. Effect of the selective beta-AR antagonists showed variation depending on the concentration, incubation time, and histological origin of cells.Item Epigallocatechin 3-gallate applications on HT-29 and MCF-7 cell lines and evaluation of tumor suppressor gene methylation(2015) Terzi, Yunus Kasim; Kaya, Ozge Ozer; Iseri, Ozlem Darcansoy; Celik, Zerrin; Sahin, Feride IffetEpigallocatechin 3-gallate (EGCG) is an antitumor molecule and shows this activity by binding to the active center of a methyltransferase enzyme (DNMT1). The methylation of DNA sequences of tumor suppressor and DNA repair genes is observed in different stages of carcinogenesis. In this study, we analyzed the effect of EGCG on the methylation status of 25 tumor suppressor genes in cancer cell lines HT-29 and MCF-7. HT-29 and MCF-7 cells were incubated with 10 mu M, 20 mu M, and 50 mu M and 1 mu M, 5 mu M, and 10 mu M EGCG for 48 h, respectively. We found promoter hypermethylation of (1) CDH13, GATA5, and RAR beta genes in MCF-7 cell line and (2) RAR beta, ESR1, PAX6, WT1, CADM1, CHFR, CDH13, and GATA5 genes in HT-29 cell line. However, (3) after EGCG application, no changes in methylation status were detected in our samples. Our results suggest that methylation status of tumor suppressor genes did not change with different EGCG doses.