Authors:Rubina Tu¨nde Szabó, Mária Kovács-Weber, Márta Erdélyi, Krisztián Balogh, Natasa Fazekas, Ákos Horváth, Miklós Mézes, and Balázs Kovács
et al., 2012 ).
The study of Hafner et al. ( 2012 ) showed the migration of DNA in the spleen of roosters after 17-day-long T-2 toxin exposure. Less than 1.5 mg of T-2 toxin/kg feed DNA breaking was not visible by the comet assay in leukocytes
DNA Comet Assay method was carried out to detect irradiation treatment of some foods like meat, spices, beans and lentils.
The fresh meat of cow and duck were irradiated up to radiation doses of 3 kGy, the spices (cardamoms and cumin black) were
irradiated to radiation doses of 5, 10, 15 and 20 kGy while the beans (black beans and white beans) and lentils (red and green
lentils) were irradiated to 0.5 and 1 kGy. All the foods were then analyzed for radiation treatment using simple microgel
electrophoresis of single cells or nuclei (DNA Comet Assay). Sedimentation, lysis and staining times were adjusted to get
optimized conditions for correct and easy analysis of each food. Using these optimized conditions, it was found out that radiation
damaged DNA showed comets in case of irradiated food samples, whereas in non-treated food samples, round or conical spots
of stained DNA were visible. Shape, length and intensity of these comets were also radiation dose dependent. Screening of
unirradiated and irradiated samples by Comet Assay was successful in the case of all the foods under consideration under the
optimized conditions of assay. Therefore, for different kinds of irradiated foods studied in the present study, the DNA Comet
Assay can be used as a rapid, simple and inexpensive screening test.
Authors:Franco Cataldo, Pietro Ragni, Susana Iglesias-Groth, and Arturo Manchado
The sulphur-containing proteinaceous amino acids l-cysteine, l-cystine and l-methionine were irradiated in the solid state to a dose of 3.2 MGy. This dose corresponds to that delivered by radionuclide
decay in a timescale of 1.05 × 109 years to the organic matter buried at a depth >20 m in comets and asteroids. The purity of the sulphur-containing amino acids
was studied by differential scanning calorimetry (DSC) before and after the solid state radiolysis and the preservation of
the chirality after the radiolysis was studied by chirooptical methods (optical rotatory dispersion, ORD) and by FT-IR spectroscopy.
Although the high radiation dose of 3.2 MGy delivered, all the amino acids studied show a high radiation resistance. The best
radiation resistance was offered by l-cysteine. The radiolysis of l-cysteine leads to the formation of l-cystine. The radiation resistance of l-methionine is not at the level of l-cysteine but also l-methionine is able to survive the dose of 3.2 MGy. Furthermore in all cases examined the preservation of chirality after
radiolysis was clearly observed by the ORD spectroscopy although a certain level of radioracemization was measured in all
cases. The radioracemization is minimal in the case of l-cysteine and is more pronounced in the case of l-methionine. In conclusion, the study shows that the sulphur-containing amino acids can survive for 1.05 × 109 years and, after extrapolation of the data, even to the age of the Solar System i.e. to 4.6 × 109 years.