Human lymphocytes pre-exposed to 10 mGy or 50 mGy of X-rays become less sensitive to subsequent large dose irradiation, exhibited lower rate of chromosome aberration than expected. This adaptive response could be inhi...Human lymphocytes pre-exposed to 10 mGy or 50 mGy of X-rays become less sensitive to subsequent large dose irradiation, exhibited lower rate of chromosome aberration than expected. This adaptive response could be inhibited by cycloheximide, a protein synthesis inhibitor for successive 2 h period ranging from 0.5h before to 4h after the low dose exposure, indicating that the adaptive response was directly related with the protein synthesis.展开更多
Objective This paper is to explore the DNA repair mechanism of immune adaptive response （AR） induced by low dose radiation （LDR）, the changes of mRNA levels and protein expressions of p53, ATM, DNA-PK catalytic su...Objective This paper is to explore the DNA repair mechanism of immune adaptive response （AR） induced by low dose radiation （LDR）, the changes of mRNA levels and protein expressions of p53, ATM, DNA-PK catalytic subunit （DNA-PKcs） and PARP-1 genes in the LDR-induced AR in EL-4 cells. Methods The apoptosis and cell cycle progression of EL-4 cells were detected by flow cytometry in 12 h after the cells received the pre-exposure of 0.075 Gy X-rays （inductive dose, D 1） and the succeeding high dose irradiation （challenge dose, D2; 1.0, 1.5, and 2.0 Gy X-rays, respectively） with or without wortmannin （inhibitor of ATM and DNA-PK） and 3-aminobenzamid （inhibitor of PARP-1）. And the protein expressions and mRNA levels related to these genes were detected with flow cytometry and reverse transcription-polymerase chain reaction in 12 h after irradiation with D2. Results The mRNA and protein expressions of p53 and PARP-1 in EL-4 cells in the D1 ＋ D2 groups were much lower than those in the D2 groups, and those of PARP-1 in the 3-AB ＋ D2 and the 3-AB ＋ D1 ＋ D2 groups were much lower than those in the D2 and the D1 ＋ D2 groups. The percentage of apoptotic EL-4 cells in the 3-AB ＋ D1 ＋ D2 groups was much higher than that in the D1 ＋ D2 groups, that in the G0/G1 and the G2 ＋ M phases was much higher, and that in the S phase were much lower. Although the ATM and DNA-PKcs mRNA and protein expressions in wortmannin ＋ D1 ＋ D2 groups were much lower than those in the D1 ＋ D2 groups, there were no significant changes in the apoptosis and cell cycle progression between the wortmannin ＋ D1 ＋ D2 and the D1 ＋ D2 groups. Conclusion PARP-1 and p53 might play important roles in AR induced by LDR.展开更多
An identification of Phe dipeptide from L-phenylalanine monomers after keV nitro- gen and argon ion implantation, by using the HPLC （high performance liquid chromatography） and LC-MS（liquid chromatography mass spec...An identification of Phe dipeptide from L-phenylalanine monomers after keV nitro- gen and argon ion implantation, by using the HPLC （high performance liquid chromatography） and LC-MS（liquid chromatography mass spectrometer） methods is reported. The results showed a similar yield behavior for both ion species, namely： 1） the yield of dipeptides under alkalescent conditions was distinctly higher than that under acidic or neutral conditions; 2） for different ion species, the dose-yield curves tracked a similar trend which was called a counter-saddle curve. The dipeptide formation may implicate a recombination repair mechanism of damaged biomolecules that energetic ions have left in their wake. Accordingly a physicochemical self-repair mechanism by radiation itself for the ion-beam radiobiological effects is proposed.展开更多
文摘Human lymphocytes pre-exposed to 10 mGy or 50 mGy of X-rays become less sensitive to subsequent large dose irradiation, exhibited lower rate of chromosome aberration than expected. This adaptive response could be inhibited by cycloheximide, a protein synthesis inhibitor for successive 2 h period ranging from 0.5h before to 4h after the low dose exposure, indicating that the adaptive response was directly related with the protein synthesis.
基金supported by the National Natural Science Foundation of China(30570546 and 30870747)the Natural Science Foundation of Jilin Province (20090458 and 201015183)+1 种基金the Young Teachers Innovative Foundation of Jilin University(421010043430)the Young Scholars Research Foundation Program of China-Japan Union Hospital(2009)
文摘Objective This paper is to explore the DNA repair mechanism of immune adaptive response （AR） induced by low dose radiation （LDR）, the changes of mRNA levels and protein expressions of p53, ATM, DNA-PK catalytic subunit （DNA-PKcs） and PARP-1 genes in the LDR-induced AR in EL-4 cells. Methods The apoptosis and cell cycle progression of EL-4 cells were detected by flow cytometry in 12 h after the cells received the pre-exposure of 0.075 Gy X-rays （inductive dose, D 1） and the succeeding high dose irradiation （challenge dose, D2; 1.0, 1.5, and 2.0 Gy X-rays, respectively） with or without wortmannin （inhibitor of ATM and DNA-PK） and 3-aminobenzamid （inhibitor of PARP-1）. And the protein expressions and mRNA levels related to these genes were detected with flow cytometry and reverse transcription-polymerase chain reaction in 12 h after irradiation with D2. Results The mRNA and protein expressions of p53 and PARP-1 in EL-4 cells in the D1 ＋ D2 groups were much lower than those in the D2 groups, and those of PARP-1 in the 3-AB ＋ D2 and the 3-AB ＋ D1 ＋ D2 groups were much lower than those in the D2 and the D1 ＋ D2 groups. The percentage of apoptotic EL-4 cells in the 3-AB ＋ D1 ＋ D2 groups was much higher than that in the D1 ＋ D2 groups, that in the G0/G1 and the G2 ＋ M phases was much higher, and that in the S phase were much lower. Although the ATM and DNA-PKcs mRNA and protein expressions in wortmannin ＋ D1 ＋ D2 groups were much lower than those in the D1 ＋ D2 groups, there were no significant changes in the apoptosis and cell cycle progression between the wortmannin ＋ D1 ＋ D2 and the D1 ＋ D2 groups. Conclusion PARP-1 and p53 might play important roles in AR induced by LDR.
基金the Innovative Project of Chinese Academy of Science:Single Ion Beam Micro-irradiation Technology of Molecular and Cytology Effect Research(KSCX2-SW-324)
文摘An identification of Phe dipeptide from L-phenylalanine monomers after keV nitro- gen and argon ion implantation, by using the HPLC （high performance liquid chromatography） and LC-MS（liquid chromatography mass spectrometer） methods is reported. The results showed a similar yield behavior for both ion species, namely： 1） the yield of dipeptides under alkalescent conditions was distinctly higher than that under acidic or neutral conditions; 2） for different ion species, the dose-yield curves tracked a similar trend which was called a counter-saddle curve. The dipeptide formation may implicate a recombination repair mechanism of damaged biomolecules that energetic ions have left in their wake. Accordingly a physicochemical self-repair mechanism by radiation itself for the ion-beam radiobiological effects is proposed.
