No abstract available.
Genetics ; Radiation, Ionizing

Apoptosis ; radiation effects ; Cell Cycle ; radiation effects ; Cells, Cultured ; Electromagnetic Fields ; Gene Expression ; radiation effects ; Mutation ; radiation effects ; Recombination, Genetic ; radiation effects ; Yeasts ; cytology ; genetics ; radiation effects

Drosophila melanogaster (Oregon-R, Oak Ridge strain) males, 19 to 21 hours old, were X-rayed with a total dose of 1000r. or 3000 r. given in two equal fractions of 500 r. or 1500 r. at a dose rate of 500r. per minute, except for Experiment #2 in which they were given a single dose of 1000 r. at 24 +/- 1 degree C in several gas environments, with a time interval of 40 minutes between the two doses. At each Change of gas(es),the system was evacuated to remove all gases, then Hushed with helium for 1 minute. Tests using CO were carried out in the dark and the others m the light, both at 1 atmosphere of the gas or gas mixture. In order to study the genetic radiation damage and its modification by several gases the frequencies of dominant lethals and translocations induced in cells which were in different stages of spermatogenesis were scored using seven sequential 2-day mating over a two-week test period. Data are prtsented which indicate that: 1) The frequency of dominant lethals increased from sperm to spermatids and meiotic cells, then decreased in spermatogonial cells which were the least susceptible to X-rays. 2) The cycle of damage for dominant lethals is similar to that for translocations, but does not coincide with it completely, and the peaks of damage for both are located in the early postmeiotic stages, and the cycle of frequencies of translocations coincides with that of percentages of sterility of F1 the coincidence frequencies between translocations and the sterility demonstrates that the mechanisms of damage for both are related, at least in part. 3) The NO effect on sperm and late spermatids is more drastic than the oxygen effect, but a major fraction of the effect is to cause the death of the sperm. 4) The carbon monoxide (CO) during radiation increase genetic damage above the other gases tested, and it is possible to conclude that the duration(s) of 4 minutes of gases in post-treatments is too short to modify the damage. 5) There are few (or no) translocations recovered from premeiotic cells. 6) The Y-chromosome was involved in 10.8% of total breaks, or about 1/4 as frequently as the two autosomes tested, and chromosomes 2 and 3 equally participated in an interchange.
Animal ; Chromosome Aberrations/radiation effects ; Drosophila ; Male ; Meiosis/radiation effects* ; Radiation Genetics* ; Spermatozoa/radiation effects* ; Time Factors

OBJECTIVETo investigate the effects of radiosensitivity and X-ray dose on the expression of miR-7 in nasopharyngeal carcinoma (NPC) cells.

METHODSLow radiosensitive NPC cells CNE-1 and high radiosensitive NPC cells CNE-2 were exposed to 0, 2 and 8 Gy X-ray. The total RNAs of the cell lines were extracted 10 h after radiation for reverse transcription of miR-7 and 18S rRNA by stem-loop primer and random hexamers, respectively. The non-irradiated CNE-1 cells served as the control sample and the relative quantity of the expression level was calculated after real-time PCR using SyBR green.

RESULTSmiR-7 expression differed significantly between CNE-1 and CNE-2 cells (4.49-/+3.62 vs 1.29-/+1.10, F=135.483, P<0.001). The radiation dose also significantly affected the expression of miR-7 in NPC cells (F=39.565, P<0.001). CNE-1 cells with a 2 Gy exposure had the highest expression level of miR-7, while the non-irradiated CNE-1 cells had the lowest expression. CNE-2 cells exposed to 2 Gy X-ray had the lowest expression level of miR-7 and the non-irradiated CNE-2 cells had the highest.

CONCLUSIONRadiosensitivity and radiation dose of X-ray have significant effect on the expression of miR-7 in NPC cells, indicating that miR-7 plays an important role in radioresistance of NPC cells to X-ray, and suppressed miR-7 expression may elevate the radiosensitivity of NPC cells.

Apoptosis ; radiation effects ; Carcinoma ; Cell Line, Tumor ; Dose-Response Relationship, Radiation ; Gene Expression Regulation, Neoplastic ; radiation effects ; Humans ; MicroRNAs ; genetics ; Nasopharyngeal Neoplasms ; genetics ; Radiation Tolerance ; genetics ; X-Rays

OBJECTIVETo study the mutagenic effect of gamma-rays on Coix lacryma-jobi var. ma-yuen.

METHODPhysiological and mutagenic effects of gamma-rays on C. lacryma-jobi var. ma-yuen dormant seeds were studied. The germination percentage, seeding survival, seeding height and root length of M1 plants and the frequency of chlorophyll mutation in M2 generation were selected as criteria.

RESULTThe gamma-rays showed obvious inhibitory action to the seedling growth, and a strong ability in inducing the chlorophyll mutation.

CONCLUSIONThe gamma-rays is one kind of C. lacryma-jobi var. ma-yuen effective mutagen. The appropriate dose of gamma-rays is 450 Gy for C. lacryma-jobi var. ma-yuen dormant seeds.

Chlorophyll ; metabolism ; Chloroplasts ; genetics ; metabolism ; radiation effects ; Cobalt Radioisotopes ; Coix ; genetics ; growth & development ; radiation effects ; Gamma Rays ; Germination ; genetics ; physiology ; radiation effects ; Inclusion Bodies ; Mutagenesis ; radiation effects ; Mutation ; radiation effects ; Plant Roots ; genetics ; growth & development ; radiation effects ; Radiation Dosage ; Seedlings ; genetics ; growth & development ; radiation effects ; Seeds ; genetics ; growth & development ; radiation effects

BACKGROUND AND OBJECTIVEThe mRNA levels of 59 genes, detected by cDNA microarray, were up-regulated in the radioresistant human esophageal cacinoma cell line TE13R120 as compared with its parental cell line TE13 before and after radiation, and the expression of NRAGE gene showed a gradually up-regulating tendency. This study aimed to further detect the differences of NRAGE gene and protein expression and apoptosis between TE13R120 and TE13 cells, and to investigate the relationship between the NRAGE and the radioresistance of TE13R120 cells and its mechanism.

METHODSThe two cell lines were irradiated by ⁶⁰Co γ-ray at different conditions. Reverse transcription-polymerase chain reaction (RT-PCR), Western blot, and immunocytochemistry were used to detect the expression of NRAGE. Flow cytometry (FCM) was used to detect the cell apoptosis before and after irradiation.

RESULTSThe mRNA level of NRAGE was higher in TE13R120 cells than in TE13 cells before and after irradiation (before radiation: 0.25 ± 0.03 vs. 0.49 ± 0.03; 4 Gy 4 h: 0.31 ± 0.03 vs. 0.53 ± 0.02; 4 Gy 16 h: 0.32 ± 0.04 vs. 0.59 ± 0.04; 4 Gy 24 h: 0.36 ± 0.05 vs. 0.72 ± 0.04; 2 Gy 12 h: 0.32 ± 0.02 vs. 0.64 ± 0.04; 6 Gy 12 h: 0.36 ± 0.02 vs. 0.79 ± 0.05; 10 Gy 12 h: 0.46 ± 0.04 vs. 0.85 ± 0.01; P < 0.01), and the mRNA level of NRAGE was increased gradually with the increase of radiation dose and time in the two cell lines (P < 0.05 and P < 0.01). Western blot results showed no difference of NRAGE protein level in cytoplasm between TE13R120 cells and TE13 cells before and after irradiation, but its level in nuclei was higher in TE13R120 cells than in TE13 cells at different radiation time and dosages. Immunocytochemistry showed similar results as Western blot. FCM showed no significant difference in apoptosis rate between TE13R120 and TE13 cells before and after radiation.

CONCLUSIONNRAGE may play an important role in the radiation responses of the two cell lines, and may participate in the formation of radioresistance of TE13R120 cells by changing its subcellular localization, but its relationship with cell apoptosis has not been confirmed.

Antigens, Neoplasm ; genetics ; metabolism ; radiation effects ; Apoptosis ; radiation effects ; Cell Line, Tumor ; radiation effects ; Cobalt Radioisotopes ; Esophageal Neoplasms ; metabolism ; pathology ; Humans ; Neoplasm Proteins ; genetics ; metabolism ; radiation effects ; RNA, Messenger ; metabolism ; radiation effects ; Radiation Tolerance ; Radiotherapy Dosage ; Time Factors ; Up-Regulation

This study examined the osteogenic effect of electromagnetic fields (EMF) under the simulated in vivo conditions. Rat bone marrow mesenchymal stem cells (BMSCs) and rat osteoblasts were co-cultured and exposed to 50 Hz, 1.0 mT EMF for different terms. Unexposed single-cultured BMSCs and osteoblasts were set as controls. Cell proliferation features of single-cultured BMSCs and osteoblasts were studied by using a cell counting kit (CCK-8). For the co-culture system, cells in each group were randomly chosen for alkaline phosphatase (ALP) staining on the day 7. When EMF exposure lasted for 14 days, dishes in each group were randomly chosen for total RNA extraction and von Kossa staining. The mRNA expression of osteogenic markers was detected by using real-time PCR. Our study showed that short-term EMF exposure (2 h/day) could obviously promote proliferation of BMSCs and osteoblasts, while long-term EMF (8 h/day) could promote osteogenic differentiation significantly under co-cultured conditions. Under EMF exposure, osteogenesis-related mRNA expression changed obviously in co-cultured and single-cultured cells. It was noteworthy that most osteogenic indices in osteoblasts were increased markedly after co-culture except Bmp2, which was increased gradually when cells were exposed to EMF. Compared to other indices, the expression of Bmp2 in BMSCs was increased sharply in both single-cultured and co-cultured groups when they were exposed to EMF. The mRNA expression of Bmp2 in BMSCs was approximately four times higher in 8-h EMF group than that in the unexposed group. Our results suggest that Bmp2-mediated cellular interaction induced by EMF exposure might play an important role in the osteogenic differentiation of BMSCs.
Alkaline Phosphatase ; biosynthesis ; Animals ; Bone Marrow Cells ; cytology ; radiation effects ; Cell Differentiation ; genetics ; radiation effects ; Cell Proliferation ; radiation effects ; Coculture Techniques ; Electromagnetic Fields ; Mesenchymal Stromal Cells ; radiation effects ; Osteoblasts ; radiation effects ; Osteogenesis ; genetics ; radiation effects ; Rats

To study the genic and non-genic regulation of 50 Hz 0.6 mT pulsed electromagnenic fields (PEMF) on rat calvarial osteoblasts (ROB) differentiation.ROBs were achieved by enzyme digestion, and treated with 50 Hz 0.6 mT PEMFs for 1.5 hours after subculture. The alkaline phosphatase (ALP) activity, mRNA transcription of ALP, Runx2 and OSX and protein expression of Runx2 and OSX were detected at 0, 3, 6, 9 and 12 hours after PEMF treatment.The ALP activity at 3 hours after treatment was significantly higher than that in the control(<0.01), while the mRNA transcription of ALP began to increase at 6 hours after treatment. The mRNA transcription of Runx2 increased immediately after treatment and regressed at 6 hours, then increased again. The protein expression of it corresponded but with a little lag. The mRNA transcription of OSX also raised instantly after treatment, then returned to the level of control at 6 hours, and lower than control at 12 hours significantly. The protein expression of it also corresponded but with a bit delay.There are genic regulation for the protein expression of Runx2 and OSX, and non-genic regulation for the ALP activity on the process of 50 Hz 0.6 mT PEMFs prompts ROBs differentiation.
Alkaline Phosphatase ; metabolism ; radiation effects ; Animals ; Cell Differentiation ; genetics ; radiation effects ; Cells, Cultured ; Core Binding Factor Alpha 1 Subunit ; metabolism ; radiation effects ; Electromagnetic Fields ; Osteoblasts ; chemistry ; radiation effects ; Osteogenesis ; genetics ; radiation effects ; Rats ; Transcription Factors ; metabolism ; radiation effects

OBJECTIVETo study the effects of UV irradiation on DNA ligation and transformation efficiency of the expression vector into competent bacterial cells.

METHODSThe expression vector was digested with the restriction enzyme SfiI, and the purified target DNA fragments were exposed to UV light at different wavelengths. Ligation and transformation experiments with the exposed fragments were carried out and the colony number and transformation efficiency were assessed.

RESULTSThe transformation efficiency of the DNA with a 5-min exposure to 302 nm UV was 60 colonies per nanogram of the DNA, as compared with 20400 for the DNA exposed to 365 nm UV. The time course experiment showed that prolonged DNA exposure to 365 nm UV light was associated with lowered transformation efficiency. DNA exposure for 30 min caused a reduction of the transformation efficiency to lower than 50% compared to that of DNA without UV exposure. But with a 15 min exposure, the DNA maintained a transformation efficiency more than 70%, which was sufficient for most molecular biology experiments.

CONCLUSIONIn construction of the expression vector, it is advisable to prevent the target DNA from UV exposure. When UV exposure is essential, we suggest that 365 nm UV be used and the exposure time controlled within 15 min.

Bacteria ; genetics ; DNA Damage ; radiation effects ; DNA Repair ; Genetic Vectors ; radiation effects ; Transformation, Bacterial ; radiation effects ; Ultraviolet Rays

Effects of gamma irradiation on the worm survival and chromosomal aberration of Clonorchis sinensis were studied. The metacercariae irradiated with various amounts of gamma radiation (ranging from 5 Gy to 50 Gy) were fed to rats, and the effects were compared with those of non-irradiated controls. Recovery rates of adult worms in irradiated groups were reduced gradually as increasing of the irradiation doses. No worm was recovered from rats which were fed with 50 Gy irradiated metacercariae. The chromosome number was 2n = 56 in all worms from all experimental groups. However, the groups irradiated with 20 Gy, 25 Gy or 30 Gy showed variations in the chromosome number, depending on different cells in the same individual. Radiation doses used in this study did not appear to induce chromosome aberrations, however, irradiation with 30 Gy showed slightly reduced chromosome size.
Animals ; Chromosome Aberrations/*radiation effects ; Clonorchis sinensis/*genetics/physiology/*radiation effects ; Dose-Response Relationship, Radiation ; Gamma Rays/*adverse effects ; Rats