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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 18:15 |
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Conference: Bucharest University Faculty of Physics 2017 Meeting
Section: Biophysics; Medical Physics
Title:
Fluorescent studies of biological membrane fluidity
Authors:
Ionela M. COJANU(1), Mihaela BACALUM(2), Claudia G. CHILOM(1)
Affiliation:
1) Department of Electricity, Solid Physics and Biophysics, Faculty of Physics, University of Bucharest, ROMANIA
2) Department of Life and Environmental Physics, Horia Hulubei National Institute of Physics and Nuclear Engineering, Magurele
E-mail
claudiafir@gmail.com
Keywords:
Biological membrane, Laurdan, peptides, fluidity, generalized polarization fluorescence
Abstract:
Biological membranes are essential parts of living cells, with basic functions in cells defining, protection, and communication with external environment. An important property of cell membranes, responsible for the dynamic nature of these structures, is their membrane fluidity. In this study, Laurdan was used as a fluorescent probe to study the membrane fluidity of four cell lines: L929 (fibroblast from mouse subcutaneous connective tissue), HT-29 (human colorectal adenocarcinoma), HepG2 (human hepatocellular carcinoma), MG-63 (human bone osteosarcoma). Due to Laurdan sensitivity to the environment polarity, by its fluorescence, one can detect the changes in the membrane phase. The four types of cells exhibit different membrane fluidity at 37 oC. Cell membrane fluidity is also affected by the temperature changes. Therefore, in the first part of the study, the temperature dependences of Laurdan generalized polarizations, GPs, in the four cell lines at three temperatures: 37 oC, 25 oC, and 15 oC were examined. In the second part of the study, the four cell lines were treated with two peptides: Gramicidin S (GS), produced by Bacillus brevis and Melittin (ML) extracted from the bee venom. The exposure time of cells to these peptides was very short, so that the experimental data present the direct interaction between these peptides and the cell membranes. The results showed that both GS and ML promote the cell membranes to rigid phases.
Acknowledgement:
This work was accomplished with the financial support of the IUNC Project, 04-2-1132-2017/2019, The effect of proton beam irradiation on the in vitro action of antitumor drugs. Biological studies were accomplished with the financial support of Romanian National Authority for Scientific Research, CNDI-UEFISCDI, Project number: PN 16 42 02 03.
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