TY - JOUR A1 - Schröter, Maria-Astrid A1 - Meyer, Susann A1 - Hahn, Marc Benjamin A1 - Solomun, Tihomir A1 - Sturm, Heinz A1 - Kunte, Hans-Jörg T1 - Ectoine protects DNA from damage by ionizing radiation N2 - Ectoine plays an important role in protecting biomolecules and entire cells against environmental stressors such as salinity, freezing, drying and high temperatures. Recent studies revealed that ectoine also provides effective protection for human skin cells from damage caused by UV-A radiation. These protective properties make ectoine a valuable compound and it is applied as an active ingredient in numerous pharmaceutical devices and cosmetics. Interestingly, the underlying mechanism resulting in protecting cells from radiation is not yet fully understood. Here we present a study on ectoine and its protective influence on DNA during electron irradiation. Applying gel electrophoresis and atomic force microscopy, we demonstrate for the first time that ectoine prevents DNA strand breaks caused by ionizing electron radiation. The results presented here point to future applications of ectoine for instance in cancer radiation therapy. KW - Plasmid DNA pUC19 KW - Electron irradiation 30 [kV] KW - Effective irradiation dose 0.2-16 [Gy] KW - Gel electrophoresis KW - AFM intermittent contact KW - Radioprotector ectoine KW - Compatible solute PY - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-428287 SN - 2045-2322 VL - 7 IS - 1 SP - 15272, 1 EP - 15272, 7 PB - Nature AN - OPUS4-42828 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meyer, Susann A1 - Schröter, Maria-Astrid A1 - Hahn, Marc Benjamin A1 - Solumon, Tihomir A1 - Strum, Heinz A1 - Kunte, Hans-Jörg T1 - Ectoine can enhance structural changes in DNA in vitro N2 - Strand breaks and conformational changes of DNA have consequences for the physiological role of DNA. The natural protecting molecule ectoine is beneficial to entire bacterial cells and biomolecules such as proteins by mitigating detrimental effects of environmental stresses. It was postulated that ectoine-like molecules bind to negatively charged spheres that mimic DNA surfaces. We investigated the effect of ectoine on DNA and whether ectoine is able to protect DNA from damages caused by ultraviolet radiation (UV-A). In order to determine different isoforms of DNA, agarose gel electrophoresis and atomic force microscopy experiments were carried out with plasmid pUC19 DNA. Our quantitative results revealed that a prolonged incubation of DNA with ectoine leads to an increase in transitions from supercoiled (undamaged) to open circular (single-strand break) conformation at pH 6.6. The effect is pH dependent and no significant changes were observed at physiological pH of 7.5. After UV-A irradiation in ectoine solution, changes in DNA conformation were even more pronounced and this effect was pH dependent. We hypothesize that ectoine is attracted to the negatively charge surface of DNA at lower pH and therefore fails to act as a stabilizing agent for DNA in our in vitro experiments. KW - Ectoine KW - DNA KW - UV radiation PY - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-413139 VL - 7 IS - 1 SP - Article 7170, 1 EP - 10 AN - OPUS4-41313 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hahn, Marc Benjamin A1 - Meyer, Susann A1 - Schröter, Maria-Astrid A1 - Seitz, H. A1 - Kunte, Hans-Jörg A1 - Solomun, Tihomir A1 - Sturm, Heinz T1 - Direct electron irradiation of DNA in fully aqueous environment. Damage determination in combination with Monte Carlo simulations N2 - We report on a study in which plasmid DNA in water was irradiated with 30 keV electrons generated by a scanning electron microscope and passed through a 100 nm thick Si3N4 membrane. The corresponding Monte Carlo simulations suggest that the kinetic energy spectrum of the electrons throughout the water is dominated by low energy electrons (<100 eV). The DNA radiation damage, single-strand breaks (SSB) and double-strand breaks (DSB), was determined by electrophoresis. The median lethal dose of D1/2 = 1.7 ± 0.3 Gy was found to be much smaller compared to partially or fully hydrated DNA irradiated under vacuum conditions. The ratio of DSB to SSB was found to be (1:12) as compared to 1:88) found for hydrated DNA. Our method enables quantitative measurements of radiation damage to biomolecules (DNA, proteins) in solutions under varying conditions (pH, salinity, cosolutes) for an electron energy range which is difficult to probe by standard methods. KW - Plasmid DNA in water KW - Monte Carlo simulation KW - Low energy electrons KW - DNA radiation damage KW - Single-strand break (SSB) KW - Double-strand break (DSB) KW - Lethal dose KW - Radiation damage to biomolecules KW - Solutions (pH, salinity, cosolutes) PY - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-386981 SN - 1463-9076 SN - 1463-9084 VL - 19 IS - 3 SP - 1798 EP - 1805 PB - Royal Society of Chemistry AN - OPUS4-38698 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -