The purpose of this study is to investigate the mechanism of alternative responses to low dose irradiation for neuronal cell proliferation in the dentate gyrus of rats. To determine the effect of a single exposure to radiation, rats were irradiated with a single dose of 0.1, 1, 10 or 20 Gy. To determine the effect of the cumulative dose, the animals were irradiated daily with 0.01 Gy or 0.1 Gy from 1 to 4 days. The neuronal cell proliferation was evaluated using immunohistochemistry for 5-bromo-2'-deoxyuridine (BrdU), Ki-67 and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining. Four consecutive daily irradiations with a 0.01 Gy/fraction increased the number of BrdU-positive and Ki-67-positive cells in a dose dependent manner, but this did not affect the number of TUNEL-positive cells. However, there was not a dose dependent relationship for the 0.1 Gy/fraction irradiation with the number of BrdU, Ki-67 and TUNEL positive cells. Our data support the explanation that the adaptive response, induced by low-dose radiation, in the hippocampus of rats is more likely a reflection of the perturbations of cell cycle progression.
Rats, Sprague-Dawley ; Rats ; Radiation Dosage ; Neurons/*cytology/*radiation effects ; Neuronal Plasticity/*radiation effects ; Male ; Dose-Response Relationship, Radiation ; Dentate Gyrus/*cytology/*radiation effects ; Cell Survival/radiation effects ; Cell Proliferation/*drug effects ; Animals ; Adaptation, Physiological/radiation effects

OBJECTIVETo study the effect of light intensity on photosynthetic characteristics and seedling growth of Prunella vulgaris under different light intensity.

METHODThe seedling of P. vulgaris was shaded with shading net, and relative parameters were measured. The data was statistically processed.

RESULTWith the reducing light intensity, the young plant stems became slender, the leaf long increased. The plant height and net growth under 42% full light condition were significantly higher than those under the other light intensity, chlorophy II and carotenoid contents increased, as well as Chl a/b decreased under low light. Photosynthetic indicators of P(n), T(r) decreased under low light, but CO2 concentration increased, and G(s) content decreases and then increased under 10% full light intensity.

CONCLUSIONP. vulgaris manifested the different plasticity and adaptability under different light intensities. The 42% light intensity was the best and the proper shading would promote the growth of seedlings.

Adaptation, Physiological ; Chlorophyll ; metabolism ; Light ; Photosynthesis ; radiation effects ; Plant Leaves ; growth & development ; radiation effects ; Plant Stems ; growth & development ; radiation effects ; Prunella ; growth & development ; radiation effects ; Seedlings ; growth & development ; radiation effects

When cells are exposed to a low dose of a mutagenic or clastogenic agent, they often become less sensitive to the effects of a higher dose administered subsequently. Such adaptive responses were first described in Escherichia coli. Studies on mammalian cells have been limited to human lymphocytes exposed to low doses of an alkylating agent. In this study, the adaptive response to 1 cGy of gamma rays was investigated in human tumor cells using two human hepatoma cell lines, Hep G2 and Hep 3B. Experiments were carried out by delivering 1 cGy followed by 50 cGy of gamma radiation and chromatid breaks were scored as an endpoint. The results of this study indicate that prior exposure to 1 cGy of gamma rays reduces the number of chromatid breaks induced by subsequent higher doses (50 cGy). The time necessary for the expression of the adaptive response was determined by varying the time interval between the two doses from 1 hour to 72 hours. In G2 chromatids, the adaptive response was observed both at short time intervals, as early as 1 hour, and at long time intervals. In S chromatids, however, the adaptive response was shown only at long time intervals. When 3-aminobenzamide, an inhibitor of poly (ADP-ribose) polymerase, was added after 50 cGy, adaptive responses were abolished in all the experimental groups. Therefore, it is suggested that the adaptive response can be observed in human hepatoma cell lines, which is first documented through this study.
*Adaptation, Physiological ; Carcinoma, Hepatocellular/genetics ; Chromosome Aberrations ; *Gamma Ray ; Human ; Liver Neoplasms/genetics ; Radiation Tolerance/*physiology ; Support, Non-U.S. Gov't ; Tumor Cells, Cultured/*radiation effects

Environmental stresses and the continuing deterioration of arable land, along with an explosive increase in world population, pose serious threats to global agricultural production and food security. Improving the tolerance of the major crop plants to abiotic stresses has been a main goal in agriculture for a long time. As rice is considered one of the major crops, the development of new cultivars with enhanced abiotic stress-tolerance will undoubtedly have an important effect on global food production. The transgenic approach offers an attractive alternative to conventional techniques for the genetic improvement of rice cultivars. In recent years, an array of stress-related genes has already been transferred to rice to improve its resistance against abiotic stresses. Many transgenic rice plants with enhanced abiotic stress-tolerance have been obtained. This article focuses on the progress in the study of abiotic stress tolerance in transgenic rice breeding.
Adaptation, Physiological ; genetics ; Agriculture ; methods ; trends ; Breeding ; Light ; Oryza ; drug effects ; genetics ; growth & development ; radiation effects ; Plant Proteins ; genetics ; Plants, Genetically Modified ; drug effects ; genetics ; growth & development ; radiation effects ; Sodium Chloride ; pharmacology ; Temperature

OBJECTIVETo study the adaptive response mechanisms in high background radiation area (HBRA) among Yangjiang local people through gene and protein expression of receptor for advanced glycation end products (RAGE) and S100A6 in peripheral blood and sputum in inhabitants of HBRA.

METHODSA total of 53 male inhabitants were selected from HBRA in Yangjiang as the exposure group, while 53 male inhabitants were selected from Enping (control area, CA)as the control group. The content of RAGE and S100A6 gene and protein were detected by RT-PCR and Western blotting assay. Thermo luminescent dosemeter(TLD) assay was used to measure the outside dose and estimate the effective dose.

RESULTSThe effective dose in CA and HBRA was respectively 1.95 mSv and 6.24 mSv, which was 3 fold difference. Compared with CA, RAGE and S100A6 expression were significantly reduced in both gene and protein level in HBRA. The relative median mRNA expression of RAGE and S100A6 in peripheral blood were respectively 0.28, 1.06 and 0.16, 0.79 in CA and HBRA group, there was significance (with analysis Z values of -2.587 and -2.328 respectively, P < 0.05) with Wilcoxon rank test. For the protein of sputum, the relative median expression were respectively 2.98, 2.25 and 0.53, 0.47 with significant difference (with analysis Z values of -2.201 and -2.366 respectively, P < 0.05) by Wilcoxon rank test.

CONCLUSIONThe low expression of RAGE and S100A6 in HBRA group might be correlated with the adaptive response and the low mortality of cancer in HBRA.

Adaptation, Physiological ; radiation effects ; Background Radiation ; Cell Cycle Proteins ; metabolism ; China ; Humans ; Male ; Middle Aged ; Receptor for Advanced Glycation End Products ; Receptors, Immunologic ; metabolism ; S100 Calcium Binding Protein A6 ; S100 Proteins ; metabolism ; Sickness Impact Profile