Influence of very low doses of ionizing radiation on Synechococcus lividus metabolism during the initial growth phase

1986 ◽  
Vol 144 (3) ◽  
pp. 286-290 ◽  
Author(s):  
Annie Conter ◽  
Dominique Dupouy ◽  
Christine Delteil ◽  
Hubert Planel
Keyword(s):  
Ionizing Radiation ◽  
Growth Phase ◽  
Initial Growth ◽  
Low Doses ◽  
Synechococcus Lividus

Radiopharmacology: Hazard or/and Benefit

1984 ◽  
Vol 23 (02) ◽  
pp. 87-91 ◽  
Author(s):  
K. Flemming
Keyword(s):  
Ionizing Radiation ◽  
Late Effects ◽  
Radiation Risk ◽  
Dose Effect ◽  
Radiation Hazard ◽  
Radiation Doses ◽  
Low Doses ◽  
Medical Radiology ◽  
Experimental Findings ◽  
In The Beginning

SummaryIn the beginning of medical radiology, only the benefit of ionizing radiation was obvious, and radiation was handled and applied generously. After late effects had become known, the radiation exposure was reduced to doses following which no such effects were found. Thus, it was assumed that one could obtain an optimal medical benefit without inducing any hazard. Later, due to experimental findings, hypotheses arose (linear dose-effect response, no time factor) which led to the opinion that even low and lowest radiation doses were relevant for the induction of late effects. A radiation fear grew, which was unintentionally strengthened by radiation protection decrees: even for low doses a radiation risk could be calculated. Therefore, it was believed that there could still exist a radiation hazard, and the radiation benefit remained in question. If, however, all presently known facts are considered, one must conclude that large radiation doses are hazardous and low doses are inefficient, whereas lowest doses have a biopositive effect. Ionizing radiation, therefore, may cause both, hazard as well as benefit. Which of the two effects prevails is determined by the level of dose.

Characterization of gene expression profiles at low and very low doses of ionizing radiation

DNA Repair ◽  
2013 ◽  
Vol 12 (7) ◽  
pp. 508-517 ◽  
Author(s):  
Ingrid Nosel ◽  
Aurélie Vaurijoux ◽  
Joan-Francesc Barquinero ◽  
Gaetan Gruel
Keyword(s):  
Gene Expression ◽  
Ionizing Radiation ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Low Doses

scholarly journals Gamma-radiation induced damage of proteins in the thick fraction of egg white

2005 ◽  
Vol 70 (11) ◽  
pp. 1255-1262 ◽  
Author(s):  
Marija Vuckovic ◽  
Marija Radojcic ◽  
Bratoljub Milosavljevic
Keyword(s):  
Ionizing Radiation ◽  
Gel Electrophoresis ◽  
Dose Range ◽  
Polyacrylamide Gel Electrophoresis ◽  
Egg White ◽  
Oh Radical ◽  
Low Doses ◽  
Gel Structure ◽  
Exclusion Chromatography ◽  
Saturated Sample

The thick fraction of egg white saturated with either N2O or Ar was irradiated in the dose range 1.5-45 kGy at 60Co gamma source. The gel structure decomposition and other processes accompanied with changes in protein molecular mass were followed by Sephadex G-200 exclusion chromatography, denaturing SDS-polyacrylamide gel electrophoresis, viscosity and turbidity measurements. The complex behavior of viscosity was observed in the N2O saturated sample (where the hydrated electron was converted into the OH radical); the initial abrupt decrease that gradually slows down reaching the minimum at 12 kGy (?min = 2.7 mPa s) followed by the slow rise was measured. The Ar saturated sample ([eaq-]?[OH]) showed both the significantly faster initial decrease and lower viscosity minimum (?min = 2.2 mPa s). The combined Sephadex G-200 exclusion chromatography and denaturing SDS-polyacrylamide gel electrophoresis data revealed that the three-dimensional egg white (hydrated) gel structure was (efficiently) decomposed even in the N2O saturated sample. The protein scission was detected in the entire dose range studied, while the protein agglomeration is not noticed at low doses (around 1.5 kGy); however, it dominates at higher doses. In the highest dose region studied, the loss of structure in SDS-PAGE chromatograms indicates that the agglomerates are formed from protein fragments rather than from intact proteins. The continuous linear increase in turbidity was measured. The results obtained indicate that ionizing radiation causes the breakdown of the protein network of the thick fraction of egg white via the reduction of S-S bridges by the hydrated electron and the protein fragmentation due to the direct action of ionizing radiation. The protein agglomeration is initiated by the reaction of the OH radical; its inefficiency at low doses is attributed to the glucose antioxidant properties and radical immobility. .

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