Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 1Citation - Scopus: 1Biophysical Assessment of Protein Stability in Ethanol-Stressed Environments via UV Absorption and Fluorescence Spectroscopies(Elsevier, 2026) Akyuz, Ersed; Vorob'ev, Mikhail M.; Guler, GunnurMaintaining the structure and functionality of proteins is crucial in applications ranging from food preservation to pharmaceutical formulation. Ethanol, while commonly used as a solvent and preservative, can induce structural changes in proteins depending on its concentration and the specific structure of the protein itself. This study investigates the structural effects of ethanol on three types of model proteins, namely bovine serum albumin (BSA), beta-Lactoglobulin (beta-Lg), and beta-Casein (beta-Cn), by using UV-Vis spectroscopy and fluorescence spectroscopy. The conformational responses of proteins in water-EtOH solutions of various ethanol concentrations (0-10 %, v/v) were analyzed through absorbance and emission spectral changes. At increasing ethanol concentration, UV absorption data showed distinct protein-dependent spectral changes. beta-Lg and beta-Cn exhibited strong hypochromism (an absorbance decrease of similar to 25 %) and red-shifting at 222 nm and 220 nm, respectively, indicating partial unfolding and solvent exposure of aromatic residues. BSA demonstrated subtle changes, and consistent quenching in fluorescence with a continuous blue-shifting to 330 nm, suggesting a moderate overall stability and local rearrangements in its structure. beta-Cn exhibited red-shifted fluorescence and quenching, reflecting its flexible, disordered structure and heterogeneous response to solvent conditions. Statistical analysis revealed that while fluorescence spectroscopy was highly sensitive to the intrinsic differences between proteins (p < 0.001), the ethanol-induced conformational changes were too subtle to be detected as a statistically significant treatment effect. The consistency of these trends indicates a rational underlying mechanism of interaction. This reflects the subtle nature of the effect at the tested concentrations rather than the absence of an effect. Moreover, these results unveil the protein-specific effects of ethanol and strongly emphasize the importance of solvent composition in maintaining protein integrity. Ethanol concentrations up to 5 % may offer protein stability whereas high ethanol levels (>= 5-10 %) promote structural perturbations. These results will be useful for both basic scientific research, such as biophysical studies and the advancement of optical techniques, and various industrial uses.Article Citation - WoS: 2Citation - Scopus: 2Effect of Mirna Administration on Non-Small Cell Lung Cancer Cells Studied by Cellular Viability Assay and Atr-Ftir Spectroscopy Combined With Multivariate Data-Analysis(Elsevier, 2025) Dagdeviren, Melih; Guler, Gunnur; Guler, Egemen Erdem; Un, Cemal; Karabay-Yavasoglu, Nefise UlkuMicroRNAs (miRNAs), small non-coding RNAs, play a significant role in the regulation of gene expression by various mechanisms. Some miRNAs such as hsa-miR-145 (mir145), hsa-let-7a-1 (let7), hsa-miR-155 (mir155), and hsa-miR-29b (mir29b) are expressed at low levels in cancers and associated with proliferation, metastasis, invasion and apoptosis. In the current study, we aimed to investigate the effect of selected synthetic miRNAs and their combinations on the non-small cell lung cancer (NSCLC) cells (A549) by following the cell viability profile and alterations in the cellular biomolecules with biophysical features. After administration of commercial miRNAs and their various combinations to A549 cell line, each group was analyzed with cell viability assay and attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy combined with unsupervised multivariate analysis. Bioinformatics analysis was also performed to detect and to classify the target human genes obtained from the mirDB database. According to the cell viability results, the "mir29b + let7" combination and "mir155" significantly decreased the cancer cell viability whereas the "mir145 + mir29b" and "mir155 + mir145" combinations dramatically increased the cancer cell viability when compared to the control cells. The FTIR data revealed that administration of the "mir155", "mir29b + let7 + mir155", and "mir29b + let7" combinations caused a decrease in the contents of proteins, lipids and nucleic acids in A549 cells. This study suggests that those miRNA combinations might be potential targets for vaccines or miRNA-based therapies that can restore the miRNA activity and thus should be further evaluated to combat lung cancer with miRNA technology.