16 September 2022

Séminaire ICP Amitava Adhikary – 16 septembre à 14h

Prof. Amitava Adhikary, Oakland University (Rochester, USA) will give a seminar on September 16, 2022 at 2:00 pm in Magat room:

Radiation-induced Damage to DNA: An Up-to-date Review of Mechanisms

Abstract: Experimental evidence indicates that the most important cause for cell death, mutation and transformations induced by ionizing radiations is damage to DNA. The cell nucleus has a very different environment from a dilute aqueous solution owing to the high global concentration of macromolecules (DNA, RNA, proteins etc.) ranging from 65 to 220 mg/ml. Due to the high radical scavenging capacity of the cell nucleus, free radicals produced via radiolysis of surrounding water, •OH, H-atom, solvated electrons (eaq¯) (i.e., indirect effect) are largely scavenged by proteins, glutathione and biomolecules other than DNA. The indirect effect occurs principally via hydroxyl radical (•OH) reactions since •OH is far more damaging than either the H-atom or solvated electrons. Direct effect of ionizing radiation on DNA (DNA molecule plus the layer of solvation) thus accounts for up to 50% of the damage to DNA and it results in various diamagnetic products and strand breaks.

Recent advances in our understanding of various mechanisms of both direct-type and indirect effects due to the radiation of various qualities (e.g., gamma ray, ion-beam) will be the major focus of this talk. We note here that major advances of the radical chemistry to elucidate mechanisms involved in direct-type and indirect effects have resulted from our own and collaborative efforts including synthesis, electron spin resonance (ESR), pulse radiolysis, quantum chemical calculations, product analyses employing mass spectrometric techniques, and mimetic approaches based on generating radical site-specifically in DNA for example, via Norrish-type photoexcitation. Supported by the NIH NCI via grant R01 CA045424, REF (Research Excellence Fund from center for Biomedical research, OU) CBR, NSF-MRI programs and by NSCL, MSU.

16 September 2022, 14h0015h00
Salle Magat, ICP