Project description:Linear energy transfer (LET) is an important factor affecting several aspects of the irradiation effect, e.g. cell survival and mutation frequency, making the heavy-ion beam an effective mutagen. To study the mechanisms behind LET-dependent effects, expression profiling was performed after heavy-ion beam irradiation of imbibed rice seeds. Array-based experiments at three time points (0.5, 1, 2 h after the irradiation) revealed that the number of up- or down-regulated genes was highest 2 h after irradiation. Array-based experiments with four different LETs at 2 h after irradiation identified LET-independent regulated genes that were up/down-regulated regardless of the value of LET; LET-dependently regulated genes, whose expression level increased with the rise of LET value, were also identified.
Project description:Linear energy transfer (LET) is an important factor affecting several aspects of the irradiation effect, e.g. cell survival and mutation frequency, making the heavy-ion beam an effective mutagen. To study the mechanisms behind LET-dependent effects, expression profiling was performed after heavy-ion beam irradiation of imbibed rice seeds. Array-based experiments at three time points (0.5, 1, 2 h after the irradiation) revealed that the number of up- or down-regulated genes was highest 2 h after irradiation. Array-based experiments with four different LETs at 2 h after irradiation identified LET-independent regulated genes that were up/down-regulated regardless of the value of LET; LET-dependently regulated genes, whose expression level increased with the rise of LET value, were also identified.
Project description:Linear energy transfer (LET) is an important factor affecting several aspects of the irradiation effect, e.g. cell survival and mutation frequency, making the heavy-ion beam an effective mutagen. To study the mechanisms behind LET-dependent effects, expression profiling was performed after heavy-ion beam irradiation of imbibed rice seeds. Array-based experiments at three time points (0.5, 1, 2 h after the irradiation) revealed that the number of up- or down-regulated genes was highest 2 h after irradiation. Array-based experiments with four different LETs at 2 h after irradiation identified LET-independent regulated genes that were up/down-regulated regardless of the value of LET; LET-dependently regulated genes, whose expression level increased with the rise of LET value, were also identified. Oryza sativa L. 'Nipponbare' seeds were imbibed for 3 days. The seeds were irradiated with 22.5 or 50 keV/μm C-ion at a dose of 15 Gy. Gene expressions of irradiated and unirradiated embryos were measured at 0.5, 1, and 2 hours after irradiation. Three independent experiments were performed at each time and LET.
Project description:Linear energy transfer (LET) is an important factor affecting several aspects of the irradiation effect, e.g. cell survival and mutation frequency, making the heavy-ion beam an effective mutagen. To study the mechanisms behind LET-dependent effects, expression profiling was performed after heavy-ion beam irradiation of imbibed rice seeds. Array-based experiments at three time points (0.5, 1, 2 h after the irradiation) revealed that the number of up- or down-regulated genes was highest 2 h after irradiation. Array-based experiments with four different LETs at 2 h after irradiation identified LET-independent regulated genes that were up/down-regulated regardless of the value of LET; LET-dependently regulated genes, whose expression level increased with the rise of LET value, were also identified. Oryza sativa L. 'Nipponbare' seeds were imbibed for 3 days. The seeds were irradiated with 22.5 or 50 keV/μm C-ion or 63 or 80 keV/μm Ne-ion at a dose of 15 Gy. Gene expressions of irradiated and unirradiated embryos were measured at 2 hours after irradiation. Three independent experiments were performed at each time and LET.
Project description:The aim of our research is to clarify the mechanisms generating heterogeneity in response to C-ion irradiation that arise from individual genetic variations in humans. In this study, we performed whole lung C-ion irradiation using three different strains of mice to examine whether strain-dependent differences in radiation effects occur in high-LET C-ion thoracic irradiation. Murine strain-variance was evaluated by histopathological examination of intra-alveolar hemorrhage that is likely to occur during the early phase after irradiation, and of lung fibrosis during the late phase, occurring more than three months after irradiation. We also performed microarray analysis to identify the key genes that are differentially regulated in different mouse strains after C-ion irradiation and to determine the mechanism of strain-dependent pulmonary damage after high-LET C-ion irradiation. Eight-week old female inbred C3H/He Slc, C57BL/6J Jms Slc and A/J Jms Slc mice (3 kinds of mice) were used. The whole thorax of three mice was locally irradiated at 10 Gy with C-ion beams, with a reference beam, 137Cs gamma-rays (2 kinds of beam). Three mice of each strain (3 mice) were sacrificed, and immediately dissected for lung extraction at 6 h (6h sample). Lungs for three mice of each strain without irradiation were extracted at the same time as control samples (control sample). Hybridization to microarrays (Whole Mouse Genome 4x44K OligoMicroarray Kit, single color, Cyamine 3-CTP) consisting of 44,000 total spots was conducted using an Agilent Gene Expression hybridization kit. The arrays from three independent replicates for each sample (3 arrays) were scanned on an Agilent dual-laser Microarray Scanner (all from Agilent Technologies) following the manufacturer's instructions. A total of 108 samples were analyzed. 3 replicate arrays x 3 mice x 3 strains x 2 timing for sampling x 2 kinds of beam.
Project description:In this study, carbon-ion beams generated via the heavy-ion medical accelerator in Chiba (HIMAC) were targeted to growing rice seedlings (7-days-old) to examine their effect on this genome model. Both physiological parameters, such as growth, and molecular events, specially the gene expression profiles were examined immediately after irradiation (at 270 Gy dose) by rice oligo (22K) DNA microarrays. Genome-wide transcriptional profiling of radiation-response genes in rice provides us with first report on how our radioactive environment affects a plant species. Keywords: Irradiation response