WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
Browse
33 results
Search Results
Now showing 1 - 10 of 33
Article Blank Frame and Intensity Variation Distortion Detection and Restoration Pipeline for Phase-Contrast Microscopy Time-Lapse Images(Aves, 2024) Ucar, Mahmut; Iheme, Leonardo O.; Onal, Sevgi; Pesen-Okvur, Devrim; Yalcin-Ozuysal, Ozden; Toreyin, Behcet U.; Unay, DevrimIn this study, we propose a preprocessing pipeline for the detection and correction of distorted frames in time-lapse images obtained from phase-contrast microscopy. The proposed pipeline employs the average intensities of frames as a foundational element for the analysis. In order to evaluate the degree of correction required for intensity variance, a normalization technique is applied to the difference between the average intensity of a specific frame and the median average intensity of all frames within the study. Our restoration method increases the histogram similarity between the distorted and non-distorted frames, preserves trans-passing pixels in regions of interest, and mitigates the development of additional distortions. The efficacy of the proposed method was evaluated using 15 395 time-lapse image frames from 27 experiments using our own dataset and 830 time-lapse images from four different experiments obtained from the cell tracking challenge. The results of the validation demonstrate a high degree of numerical and visual accuracy of the proposed pipeline.Data Paper Knockdown of Death Receptor 5 Antisense Long Noncoding Rna and Cisplatin Treatment Modulate Similar Macromolecular and Metabolic Changes in Hela Cells(TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2022) Gürer, Dilek Cansu; Erdoğan Vatansever, İpek; Ceylan, Çağatay; Akgül, BünyaminBackground/aim: Despite great progress in complex gene regulatory mechanisms in the dynamic tumor microenvironment, the potential contribution of long noncoding RNAs (lncRNAs) to cancer cell metabolism is poorly understood. Death receptor 5 antisense (DR5-AS) is a cisplatin inducible lncRNA whose knockdown modulates cell morphology. However, its effect on cell metabolism is unknown. The aim of this study is to examine metabolic changes modulated by cisplatin and DR5-AS lncRNA in HeLa cells. Materials and methods: We used cisplatin as a universal cancer therapeutic drug to modulate metabolic changes in HeLa cervix cancer cells. We then examined the extent of metabolic changes by Fourier transform infrared spectroscopy (FTIR). We also performed transcriptomics analyses by generating new RNA-seq data with total RNAs isolated from cisplatin-treated HeLa cells. Then, we compared cisplatin-mediated transcriptomics and macromolecular changes with those mediated by DR5-AS knockdown. Results: Cisplatin treatment caused changes in the unsaturated fatty acid and lipid-to-protein ratios and the glycogen content. These observations in altered cellular metabolism were supported by transcriptomics analyses. FTIR spectroscopy analyses have revealed that DR5-AS knockdown causes a 20.9% elevation in the lipid/protein ratio and a 76.6% decrease in lipid peroxidation. Furthermore, we detected a 3.42% increase in the chain length of the aliphatic lipids, a higher content of RNA, and a lower amount of glycogen indicating relatively lower metabolic activity in the DR5-AS knockdown HeLa cells. Interestingly, we observed a similar gene expression pattern under cisplatin treatment and DR5-AS knockdown HeLa cells. Conclusion: These results suggest that DR5-AS lncRNA appears to account for a fraction of cisplatin-mediated macromolecular ametabolic changes in HeLa cervix cancer cells.Article Citation - WoS: 1Citation - Scopus: 1Cytoplasmically Localized Trna-Derived Fragments Inhibit Translation in Drosophila S2 Cells(TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2022) Hamid, Syed Muhammad; Akgül, BünyaminTransfer ribonucleic acids (tRNAs) serve not only as amino acid carriers during translation but also as a template for the biogenesis of short fragments that can regulate gene expression. Despite recent progress in the function of tRNA-derived fragments (tRFs), their intracellular localization, protein partners, and role in regulating translation are not well understood. We used synthetic tRFs to investigate their localization and function in Drosophila S2 cells. Under our experimental setting, all synthetic tRFs tested were localized at distinct sites within the cytoplasm in a similar manner in Drosophila S2 cells. Cytoplasmically-localized tRFs were positioned in close proximity to GW182 and XRN1 proteins. Functionally, tRFs, which slightly suppressed proliferation in S2 cells, inhibited translation without any major shift in the polysome profile. These results suggest that 5???-tRFs are cytoplasmically-localized and regulate gene expression through inhibition of translation in Drosophila.Article Citation - WoS: 3Citation - Scopus: 3Evaluation of Variation on Myostatin (mstn) Gene of Turkish Donkey Populations in Thrace Region of Turkey(Namık Kemal Üniversitesi, 2022) Işık, Raziye; Özdil, Fulya; Meral, SenaThe study aimed to determine the MSTN gene variation in 90 donkeys reared in the Thrace region of Turkey. Myostatin (MSTN), also named GDF-8 (growth differentiation factor 8) is a part of the transforming growth factor beta (TGF-beta) superfamily and it has a negative regulator role on muscle mass, growth and development in mammalian species. MSTN gene regulates the skeletal muscle growth in a negative way and has a significant role in homeostasis of skeletal muscles. Also, in muscle fibers balance of protein has been promoted by Myostatin factor. The total of 866 bp long partial intron 1 and 2, whole exon 2 regions of MSTN gene was amplified and PCR products analysed using DNA sequencing. In this study, a novel synonymous SNP was determined as g.4183919 G>A in the second exon region of the MSTN gene which does not cause an amino acid change in the protein. The G>A transition caused a silent mutation in leucine (leu) amino acid. Alterations in mRNA level and functionality of protein can occur due to synonymous mutations. Since leucine is an important amino acid that can avoid muscle mass loss and inhibits the expression of Myostatin, it can be said that silent mutation of Leu in donkeys may have altered the muscle mass and physical factor of donkeys in this study. Mutant leucine may have a lower efficient effect on preventing loss of muscles and causes more Myostatin protein expression. The identified SNP was firstly released and the DNA sequences of the MSTN gene in Turkish donkeys was revealed for the first time with recent study. Turkish donkeys lacked these mutations that were identified before in horses, which cause for the less might require for race ability of donkeys. The sequences of MSTN gene were submitted to the NCBI GenBank with the accession number: MW970078- MW970079. Further studies are needed to conduct, on protein and molecular levels, SNPs on the MSTN gene and their association with the morphological characters that may affect economic traits in donkey breeds.Article Citation - WoS: 14Citation - Scopus: 15Noncoding Rnas in Apoptosis: Identification and Function(TÜBİTAK, 2022) Tüncel, Özge; Kara, Merve; Yaylak, Bilge; Erdoğan, İpek; Akgül, BünyaminApoptosis is a vital cellular process that is critical for the maintenance of homeostasis in health and disease. The derailment of apoptotic mechanisms has severe consequences such as abnormal development, cancer, and neurodegenerative diseases. Thus, there exist complex regulatory mechanisms in eukaryotes to preserve the balance between cell growth and cell death. Initially, protein coding genes were prioritized in the search for such regulatory macromolecules involved in the regulation of apoptosis. However, recent genome annotations and transcriptomics studies have uncovered a plethora of regulatory noncoding RNAs that have the ability to modulate not only apoptosis but also many other biochemical processes in eukaryotes. In this review article, we will cover a brief summary of apoptosis and detection methods followed by an extensive discussion on microRNAs, circular RNAs, and long noncoding RNAs in apoptosis.Article Citation - WoS: 3Citation - Scopus: 6Improved Cell Segmentation Using Deep Learning in Label-Free Optical Microscopy Images(TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2021) Ayanzadeh, Aydın; Yalçın Özuysal, Özden; Pesen Okvur, Devrim; Önal, Sevgi; Töreyin, Behçet Uğur; Ünay, DevrimThe recently popular deep neural networks (DNNs) have a significant effect on the improvement of segmentation accuracy from various perspectives, including robustness and completeness in comparison to conventional methods. We determined that the naive U-Net has some lacks in specific perspectives and there is high potential for further enhancements on the model. Therefore, we employed some modifications in different folds of the U-Net to overcome this problem. Based on the probable opportunity for improvement, we develop a novel architecture by using an alternative feature extractor in the encoder of U-Net and replacing the plain blocks with residual blocks in the decoder. This alteration makes the model superconvergent yielding improved performance results on two challenging optical microscopy image series: a phase-contrast dataset of our own (MDA-MB-231) and a brightfield dataset from a well-known challenge (DSB2018). We utilized the U-Net with pretrained ResNet-18 as the encoder for the segmentation task. Hence, following the modifications, we redesign a novel skip-connection to reduce the semantic gap between the encoder and the decoder. The proposed skip-connection increases the accuracy of the model on both datasets. The proposed segmentation approach results in Jaccard Index values of 85.0% and 89.2% on the DSB2018 and MDA-MB-231 datasets, respectively. The results reveal that our method achieves competitive results compared to the state-of-the-art approaches and surpasses the performance of baseline approaches.Article Citation - WoS: 1Pasif Tümör Hedefli İnorganik İlaç Nanotaşıyıcıların Akciğer Sağlıklı ve Kanser Hücreleri Üzerindeki Uzun Dönemli Etkisi(Gazi Üniversitesi, 2020) Dağlıoğlu, Cenk; Kacı, Fatma Necmiyeİlaç nanotaşıyıcıları, kontrollü ve sürekli ilaç salım özellikleri ile kanser tedavisinde büyük bir potansiyele sahiptir. Bu nanotaşıyıcılar pasif veya aktif hedefli olarak ilaç taşınımı sağlayabilmektedir, ancak aktif hedefli muadillerine göre, pasif hedefli nanotaşıyıcılar tümörlü dokularda daha yavaş ve düşük düzeyde ilaç birikimi sağladığından kanserli hücrelerin yanında sağlıklı hücrelerde uzun süre bu nanotaşıyıcılara maruz kalmaktadır. Bu nedenle, bu çalışmada, pasif hedefli ilaç nanotaşıyıcıların insan akciğer epitel BEAS-2B hücreleri ve insan akciğer kanser A549 hücreleri üzerindeki uzun dönem etkileri araştırıldı. Bunun için, görüntüleme ve tedavi edici özellikleri bir arada barından Fe3O4@SiO2(FITC)-DOX formülasyonuna sahip ilaç nanotaşıyıcıları kullanıldı ve hücresel birikim, sitotoksisite ve apoptoz üzerindeki etkileri araştırıldı. Hücresel alım ve sitotoksisite deneyleri, pasif hedefli nanotaşıyıcıların kanser hücresi canlılığının etkin bir şekilde azalttığını gösterirken, 24 saatlik inkübasyon sürecinde sağlıklı hücreler üzerinde kayda değer bir etki görülmedi. Ancak 96 saatlik uzun inkübasyon sürecinde, sağlıklı BEAS-2B hücreleri makul seviyelerde nanotaşıyıcı alımı gerçekleştirirken, A549 kanser hücrelerine kıyasla düşük düzeylerde ilaç-aracılı sitotoksisite sergiledi. Ayrıca, nanotaşıyıcılar A549 hücrelerindeki apoptoz seviyelerini önemli ölçüde artırırken, BEAS-2B hücrelerinde 96 saat sonunda dahi apoptotik etki göstermedi. Bu sonuçlar, pasif hedefli inorganik ilaç nanotaşıyıcıların, sağlıklı hücreleri ihmal edilebilir düzeyde etkileyerek, antikanser ilaçların kemoterapötik etkilerini artırmada umut verici olduğunu göstermektedir.Article Citation - WoS: 2Citation - Scopus: 2Antiviral Microrna Expression Signatures Are Altered in Subacute Sclerosing Panencephalitis(Wolters Kluwer Medknow Publications, 2021) Tüfekçi, Kemal Uğur; Allmer, Jens; Çarman, Kürşat Bora; Bayram, Erhan; Topçu, Yasemin; Hız, Semra; Genç, Şermin; Yiş, UluçBackground: Subacute sclerosing panencephalitis (SSPE) is a chronic, progressive disease caused by a persistent infection of the measles virus. Despite extensive efforts, the exact neurodegeneration mechanism in SSPE remains unknown. MicroRNAs (miRNAs) have emerged as an essential part of cellular antiviral defense mechanisms and can be modulated by antiviral cytokines Such as interferon-beta (IFN-beta). Aims and Objectives: In this study, we aimed to elucidate the role of antiviral miRNAs in the pathogenesis of SSPE and analyze the interaction between host antiviral miRNAs and virus genes. Materials and Methods: Thirty-seven patients who were followed with SSPE and age-matched healthy children were included in the study. Peripheral blood mononuclear cell levels of miR-196b, miR-296, miR-431, and miR-448 were analyzed using quantitative polymerase chain reaction. Target predictions and pathway constructions of deregulated miRNAs were assessed. Results: Here, we showed that IFN-beta-modulated miR-196b, miR-296, and miR-431 were significantly upregulated in patients with SSPE compared with healthy controls. Besides, sequence complementarity analysis showed that miR-296 and miR-196b predicted binding regions in measles virus genomic RNA. Conclusion: Our findings suggest that antiviral miRNAs are upregulated in patients with SSPE, which could be a part of the host antiviral defense mechanism. </p>Article Citation - WoS: 3Citation - Scopus: 3Endogenous Heat Shock Protein Groel of A. Actinomycetemcomitans Preferentially Targets Primary Human Cd8+t Cells(TÜBİTAK, 2015) Kant, Melis; Akgül, Bünyamin; Nalbant Aldanmaz, AytenApoptosis can be used to manipulate host cells by bacterial products such as bacterial heat shock proteins (Hsp). One of the virulence factors of periodontal pathogen Aggregatibacter actinomycetemcomitans is heat shock protein GroEL (AaGroEL), which has been shown to interact with host cells. AaGroEL (Hsp64) also has the potential to modulate immune system cells. In this study we used endogenous AaGroEL protein as an antigen to study bacterial Hsp-induced apoptosis in different immune system cells. Human peripheral blood mononuclear cells and cell lines were cultured with different doses (50-1000 ng/mL) of endogenous AaGroEL at various time points. Apoptosis of the cells was measured by Annexin V and 7AAD labeling. Apoptotic cells were analyzed by flow cytometry. Our data suggested that AaGroEL-responding primary CD8+ T cells were more susceptible to apoptosis than CD4+ T cells. Furthermore, the magnitude of apoptosis in the Jurkat T cell line was higher than that in primary CD8+ T cells. There was no statistically significant level of apoptosis in the chronic myeloid leukemia (K562) cell line, which belongs to myeloid lineages. Thus, A. actinomycetemcomitans GroEL protein has more potent apoptotic effect on cells that are derived from a lymphoid progenitor.Article Citation - WoS: 1İnsan Kolon Kanseri Hücrelerine Karşı İnorganik Nanopartikül-temelli İlaç Taşıyıcı Sistemlerin Kullanılması: Partikül Büyüklüğünün Antikanser Aktivitesine Etkisi(Gazi Üniversitesi, 2020) Dağlıoğlu, CenkToday's nanoparticle technology enables the synthesis of nanoparticle-based drug delivery systems with desired size, shape, and materials especially for the applications of cancer nanomedicine. Thereby, understanding impact of particle sizes on anticancer activity will contribute to development of new drug delivery systems in cancer therapy. For this reason, in this study, two different sized nanoparticles (with -55 and 314 nm) were used as drug delivery systems and the effects of their size on the cellular uptake, cytotoxicity and apoptosis were investigated against the human colon carcinoma Caco-2 and HCT-116 cells. The results demonstrated that small nanoparticles promoted fast nanoparticle accumulation in both cancer cells in comparison to large particles. Small nanoparticles exhibited higher cytotoxicity in cancer cells with lower half maximal inhibitory concentration (IC50) values than large nanoparticles in 48 h. On the other hand, both nanoparticles showed similar IC50 values after 72 h prolonged exposure. Moreover, it was found that small nanoparticles increased the number of apoptotic cells in 24 h, whereas large nanoparticles induced apoptosis when exposure time increased to 72 h. These observations show that small sized drug delivery systems could be more efficient for improving the anticancer effects of chemotherapeutic drugs against human colon carcinoma as compared to large sized drug delivery systems.