The genes selected for expression analysis in the samples of <i>Drosophila melanogaster</i> wild-type strain <i>Canton-S</i> 72 hours after radiation exposure in doses from 5 cGy to 40 cGy.

<p>The genes selected for expression analysis in the samples of <i>Drosophila melanogaster</i> wild-type strain <i>Canton-S</i> 72 hours after radiation exposure in doses from 5 cGy to 40 cGy.</p

Influence of low doses of γ-irradiation on the lifespan of <i>Drosophila melanogaster</i>, wild-type line <i>Canton-S</i>.

<p>A–males, B–females, *—p<0.05, **—p<0.01, (Kolmogorov-Smirnov test).</p

Analysis of the gene expression by the qPCR in the samples of <i>Drosophila melanogaster</i> wild-type strain <i>Canton-S</i> 72 hours after radiation exposure in doses from 5 cGy to 40 cGy (Female/male).

<p>n–FC absolute value < 2; ǀLog₂FCǀ<1</p><p>+–Log₂FC > 1</p><p>-–Log₂FC < -1</p><p>*—p-value < 0.05</p><p>Analysis of the gene expression by the qPCR in the samples of <i>Drosophila melanogaster</i> wild-type strain <i>Canton-S</i> 72 hours after radiation exposure in doses from 5 cGy to 40 cGy (Female/male).</p

Strehler-Mildvan correlation between the parameters of the Gompertz function in <i>Drosophila melanogaster</i> wild-type <i>Canton-S</i> individuals exposed to low doses of ionizing radiation.

<p>Strehler-Mildvan correlation between the parameters of the Gompertz function in <i>Drosophila melanogaster</i> wild-type <i>Canton-S</i> individuals exposed to low doses of ionizing radiation.</p

The differentially expressed genes in <i>Drosophila melanogaster</i> males and females after the radiation exposure.

<p>A– 5 cGy, B– 10 cGy, C– 20 cGy, D– 40 cGy, 1 –males, 2 –females. Only gene changes with Log₂FC > 1 and p-value < 0.05 during at least one time range are presented.</p

Effect of Low Doses (5-40 cGy) of Gamma-irradiation on Lifespan and Stress-related Genes Expression Profile in <i>Drosophila melanogaster</i>

<div><p>Studying of the effects of low doses of γ-irradiation is a crucial issue in different areas of interest, from environmental safety and industrial monitoring to aerospace and medicine. The goal of this work is to identify changes of lifespan and expression stress-sensitive genes in <i>Drosophila melanogaster</i>, exposed to low doses of γ-irradiation (5 – 40 cGy) on the imaginal stage of development. Although some changes in life extensity in males were identified (the effect of hormesis after the exposure to 5, 10 and 40 cGy) as well as in females (the effect of hormesis after the exposure to 5 and 40 cGy), they were not caused by the organism “physiological” changes. This means that the observed changes in life expectancy are not related to the changes of organism physiological functions after the exposure to low doses of ionizing radiation. The identified changes in gene expression are not dose-dependent, there is not any proportionality between dose and its impact on expression. These results reflect nonlinear effects of low dose radiation and sex-specific radio-resistance of the postmitotic cell state of <i>Drosophila melanogaster </i>imago.</p></div

Exposure of luminous marine bacteria to low-dose gamma-radiation

The study addresses biological effects of low-dose gamma-radiation. Radioactive 137Cs-containing particles were used as model sources of gamma-radiation. Luminous marine bacterium Photobacterium phosphoreum was used as a bioassay with the bioluminescent intensity as the physiological parameter tested. To investigate the sensitivity of the bacteria to the low-dose gamma-radiation exposure (≤ 250 mGy), the irradiation conditions were varied as follows: bioluminescence intensity was measured at 5, 10, and 20°С for 175, 100, and 47 h, respectively, at different dose rates (up to 4100 μGy/h). There was no noticeable effect of gamma-radiation at 5 and 10°С, while the 20°С exposure revealed authentic bioluminescence inhibition. The 20°С results of gamma-radiation exposure were compared to those for low-dose alpha- and beta-radiation exposures studied previously under comparable experimental conditions. In contrast to ionizing radiation of alpha and beta types, gamma-emission did not initiate bacterial bioluminescence activation (adaptive response). As with alpha- and beta-radiation, gamma-emission did not demonstrate monotonic dose-effect dependencies; the bioluminescence inhibition efficiency was found to be related to the exposure time, while no dose rate dependence was found. The sequence analysis of 16S ribosomal RNA gene did not reveal a mutagenic effect of low-dose gamma radiation. The exposure time that caused 50% bioluminescence inhibition was suggested as a test parameter for radiotoxicity evaluation under conditions of chronic low-dose gamma irradiation

Effects of reduced natural background radiation on Drosophila melanogaster

Natural background radiation of Earth and cosmic rays played a relevant role during the evolution of living organisms. However, how chronic low doses of radiation can affect biological processes is still unclear. Previous data have indicated that cells grown at the Gran Sasso Underground Laboratory (LNGS, L'Aquila) of National Institute of Nuclear Physics (INFN) of Italy, where the dose rate of cosmic rays and neutrons is significantly reduced with respect to the external environment, elicited an impaired response against endogenous damage as compared to cells grown outside LNGS. This suggests that environmental radiation contributes to the development of defense mechanisms at cellular level. To further understand how environmental radiation affects metabolism of living organisms, we have recently launched the FLYINGLOW program that aims at exploiting Drosophila melanogaster as a model for evaluating the effects of low doses/dose rates of radiation at the organismal level. Here, we will present a comparative data set on lifespan, motility and fertility from different Drosophila strains grown in parallel at LNGS and in a reference laboratory at the University of L'Aquila. Our data suggest the reduced radiation environment can influence Drosophila development and, depending on the genetic background, may affect viability for several generations even when flies are moved back to normal background radiation. As flies are considered a valuable model for human biology, our results might shed some light on understanding the effect of low dose radiation also in humans