• Horticultural Science & Technology
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• v.19 no.4
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• pp.515-520
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• 2001

To observe the stimulating effect of low dose ${\gamma}$ radiation on the dormancy breaking and growth, microtubers of two potato cultivars (Solanum tuberosum L. cv. Dejima and cv. Superior) were irradiated at the dose of 0.5-30 Gy. Though it varied with cultivars and storage duration, sprouting rate, plant growth and tuber yield were promoted by 2-8 Gy irradiation in microtuber of 'Dejima' stored at low temperature. On the other hand, in microtuber of 'Superior', sprouting rate was promoted by 2 and 4 Gy irradiation, and the growth and tuber yield by 4 Gy irradiation. These results suggest that low dose of ${\gamma}$ radiation could have stimulating effects on the dormancy breaking of microtuber and potato growth.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.7
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• pp.4121-4126
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• 2013

Objective: Low dose radiation may stimulate the growth and development of animals, increase life span, enhance fertility, and downgrade the incidence of tumor occurrence.The aim of this study was to investigate the antitumor effect and hormesis in an erythrocyte system induced by low-dose radiation. Methods: Kunming strain male mice were subcutaneously implanted with S180 sarcoma cells in the right inguen as an experimental in situ animal model. Six hours before implantation, the mice were given 75mGy whole body X-ray radiation. Tumor growth was observed 5 days later, and the tumor volume was calculated every other day. Fifteen days later, all mice were killed to measure the tumor weight, and to observe necrotic areas and tumor-infiltration-lymphoreticular cells (TILs). At the same time, erythrocyte immune function and the level of 2,3-diphosphoglyceric acid (2,3-DPG) were determined. Immunohistochemical staining was used to detect the expression of EPO and VEGFR of tumor tissues. Results: The mice pre-exposed to low dose radiation had a lower tumor formation rate than those without low dose radiation (P < 0.05). The tumor growth slowed down significantly in mice pre-exposed to low dose radiation; the average tumor weight in mice pre-exposed to low dose radiation was lighter too (P < 0.05). The tumor necrosis areas were larger and TILs were more in the radiation group than those of the group without radiation. The erythrocyte immune function, the level of 2,3-DPG in the low dose radiation group were higher than those of the group without radiation (P < 0.05). After irradiation the expression of EPO of tumor tissues in LDR group decreased with time. LDR-24h, LDR-48h and LDR-72h groups were all statistically significantly different from sham-irradiation group. The expression of VEGFR also decreased, and LDR-24h group was the lowest (P < 0.05). Conclusion: Low dose radiation could markedly increase the anti-tumor ability of the organism and improve the erythrocyte immune function and the ability of carrying $O_2$. Low-dose total body irradiation, within a certain period of time, can decrease the expression of hypoxia factor EPO and VEGFR, which may improve the situation of tumor hypoxia and radiosensitivity of tumor itself.

• Korean Journal of Weed Science
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• v.32 no.3
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• pp.159-169
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• 2012

Hormesis is a dose-response phenomenon that is characterized by low-dose stimulation and high-dose inhibition. This biphasic dose-responses have had a long and extensive history in the fields of chemical toxicology, radiation biology and pharmacology. Hormesis has been found from bacteria, fungi, plants and animals, but hormesis in plants has received relatively little attention. Thus principles, occurrence, factors affecting the expression of hormetic responses, and their mechanisms in plants induced by herbicides are reviewed to provide the potentials for crop enhancement. Bromacil, bromoxynil, chloramben, propachlor, terbacil, EPTC, MSMA, and glyphosate at low doses showed stimulatory response in growth. Subtoxic dose of glyphosate increased sucrose content in sugarcane that is used worldwide in sugarcane production. Low dose of protoporphyrinogen-inhibiting herbicides induced increased pathogen defence, and low dose of triazine herbicides improved nitrogen metabolism and increased protein content in some crops. Further researches on potential benefits and risks of hormesis and its mechanism are needed for application of crop enhancement in agriculture.

• Korean Journal of Environmental Biology
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• v.25 no.2
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• pp.107-114
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• 2007

Radiation at very low doses frequently has a stimulating or hermetic effect on growth of organism. Effects of growth and survival rate on various dose of gamma irradiation in the farm culture of juvenile abalone (Haliotis discus hannai) were determined in Hallim (Jeju) from February 2004 to January 2005. The initial shell length of abalone juveniles in this study was average $3.45{\pm}0.4cm$. A change of growth after irradiation $(0{\sim}20Gy)$ was observed for 48 weeks. The highest growth rate was observed in 4 Gy-irradiated group and the lowest growth rate was observed in 20 Gy-irradiated group. The additional research about biochemical changes on juvenile abalone after irradiation should be accomplished. Continuous study for gamma radiation-induced hormesis on growth and metabolism of juvenile abalone will further induce the creation of value in ocean industry.

• Journal of Radiation Protection and Research
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• v.24 no.3
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• pp.123-129
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• 1999

Tomato (Lycopericum esculentum $M_{ILL}$ cv. Seokwang and cv. Housemomotaro) seeds were irradiated with the doses of $1{\sim}20$ Gy from $^{60}Co$ $\gamma$-ray source to investigate the effect of the low dose $\gamma$-ray radiation on the early growth and resistance to subsequent high dose of radiation. Germination rate of seeds irradiated with low dose $\gamma$-ray was enhanced in Seokwang cultivar but not in Housemomotaro cultivar. Seedling height increased in 4 Gy and 8 Gy irradiation group of both cultivars. Plant height of Seokwang cultivar was depressed in low dose irradiation group but fresh weight was increased in 2 Gy and 4 Gy irradiation group. In Housemomotaro cultivar, plant height increased in 12 Gy and 20 Gy irradiation group and fresh weight increased in 4 Gy and 20 Gy irradiation group. Growth inhibition of tomato plants by high dose radiation was noticeably reduced by pre-irradiation of low dose radiation. Resistance to subsequent high dose of radiation was enhanced in 2 Gy and 8 Gy Irradiation group of Seokwang cultivar and in 2 Gy and 12 Gy irradiation group of Housemomotaro cultivar.

• Korean Journal of Environmental Agriculture
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• v.17 no.4
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• pp.346-351
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• 1998

To investigate the hormetic effects of the low dose ${\gamma}-ray$ radiation on the germination rate, Welsh onion (Allium fistulosum L. cv. Eunchun and cv. Sukchangwoidae) seeds were irradiated at the dose of $0.5\;{\sim}24.0$ Gy with the ${\gamma}-ray$ radiation (Co-60). The germination rate of 'Eunchun' cultivar increased about 10% in the low dose ${\gamma}-ray$ irradiation group compared with that of the control. In the 'Sukchangwoidae' cultivar, the germination rate of the 4 Gy irradiation group increased 40% more than that of the control. Broadly, it seemed that the hormetic effects of the low-dose ${\gamma}-ray$ radiation were taken more promisingly in the uncultivated soil than in the fertile soil. The germination rate from the paper towel and filter paper based cultivation increased 10% and 16% more, respectively, in the 1 Gy irradiation group than that in the control group. And the electric conductivities of the above groups supposed to be taken hormetic effects of the ${\gamma}-ray$ radiation were lower than those of the control group. From the above results, it is suggested that the low dose ${\gamma}-ray$ radiation ranged from 1 Gy to 10 Gy could have the hormetic effects on the germination rate related characters in Welsh onion seeds.

• Nuclear Engineering and Technology
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• v.40 no.7
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• pp.539-550
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• 2008

Lung cancer is the most prevalent global cancer, ${\sim}90%$ of which is caused by cigarette smoking. The LNT hypothesis has been inappropriately applied to estimate lung cancer risk due to ionizing radiation. A threshold of ${\sim}1\;Gy$ for lung cancer has been observed in never smokers. Lung cancer risk among nuclear workers, radiologists and diagnostically exposed patients was typically reduced by ${\sim}40%$ following exposure to <100 mSv low LET radiation. The consistency and magnitude of reduced lung cancer in nuclear workers and occurrence of reduced lung cancer in exposed non-worker populations could not be explained by the HWE. Ecologic studies of indoor radon showed highly significant reductions in lung cancer risk. A similar reduction in lung cancer was seen in a recent well designed case-control study of indoor radon, indicating that exposure to radon at the EPA action level is associated with a decrease of ${\sim}60%$ in lung cancer. A cumulative whole-body dose of ${\sim}1\;Gy$ gamma rays is associated with a marked decrease in smoking-induced lung cancer in plutonium workers. Low dose, low LET radiation appears to increase apoptosis mediated removal of $\alpha$-particle and cigarette smoke transformed pulmonary cells before they can develop into lung cancer.

• Journal of Radiation Protection and Research
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• v.38 no.4
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• pp.166-171
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• 2013

While high-dose ionizing radiation results in long term cellular cytotoxicity, chronic low-dose (<0.2 Gy) of X- or ${\gamma}$-ray irradiation can be beneficial to living organisms by inducing radiation hormesis, stimulating immune function, and adaptive responses. During chronic low-dose-rate radiation (LDR) exposure, whole body of mice is exposed to radiation, however, it remains unclear if LDR causes changes in gene expression of the whole brain. Therefore, we aim to investigate expressed genes (EGs) and signaling pathways specifically regulated by LDR-irradiation ($^{137}Cs$, a cumulative dose of 1.7 Gy for total 100 days) in the whole brain. Using microarray analysis of whole brain RNA extracts harvested from ICR and AKR/J mice after LDR-irradiation, we discovered that two mice strains displayed distinct gene regulation patterns upon LDR-irradiation. In ICR mice, genes involved in ion transport, transition metal ion transport, and developmental cell growth were turned on while, in AKR/J mice, genes involved in sensory perception, cognition, olfactory transduction, G-protein coupled receptor pathways, inflammatory response, proteolysis, and base excision repair were found to be affected by LDR. We validated LDR-sensitive EGs by qPCR and confirmed specific upregulation of S100a7a, Olfr624, and Gm4868 genes in AKR/J mice whole brain. Therefore, our data provide the first report of genetic changes regulated by LDR in the mouse whole brain, which may affect several aspects of brain function.

• Korean Journal of Environmental Biology
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• v.17 no.3
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• pp.257-261
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• 1999

Effect of low dose gamma radiation on the growth of groundnut (Arachis hypognea L.) were investigated with respect to germination rate, seedling development and yield. Seeds of “Palpal” cultivar were irradiated with 0.5~20 Gy of ${\gamma}$ radiation in order to determine the hermetic effect of low dose radiation. The germination rate of ${\gamma}$-ray irradiation group was lower than that of the control but the seedling height of groundnut grown from seeds irradiated with low dose ${\gamma}$-ray was slightly higher than that of the control. The number of pod and kernels, and the seed yield increased by 27%, 17% and 19 %, respectively, in the 12.0 Gy irradiation group compared to that in the control group. The 100 seed weight was 87.2 g in the 4.0 Gy irradiation group, which was 11% heavier than 78.3 g in the control group. Low dose radiation showed an enhancement effects on the growth and yield components of groundnut.

• Journal of radiological science and technology
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• v.33 no.2
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• pp.143-148
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• 2010

This study is to analyze effects of the growth of Chunhyang Young Radish (CYR) and Altari Radish (AR) according to the exposure for 31 days at low dose ${\beta}$-rays. This test has one contrast sample and eleven test samples each as to AR and CYR. The seeds from contrast and test sample were planted in the culture soil after 8 seeds were chosen from each with identical condition. The accumulated dose of test samples has been measured at consistent time on a daily basis for 31 days. The growing process and germination have been measured twice at consistent time in each week. The number of leaves, length of first leave and weight have been acquired average value by measuring for 20 and 25 days, respectively after being planted. The result of test sample in case of 25 days shows that 5% increase in length and 36% increase in weight for AR each at accumulated dose 0.01 Gy compared to the contrast sample. And the length of CYR has increased by 13~17% and 1% at accumulated dose 0.01~0.08 Gy and 0.3 Gy compared to the contrast sample. For the weight at accumulated dose 0.05 Gy and 0.23 Gy has increased by 36% and 2% compared to contrast sample. As to the number of leaves, AR has increased by 0~50% at accumulated dose 0.01-0.32 Gy compared to contrast sample. It also shows that the CYR has increased to 0~67% at accumulated dose 0.01-0.62 Gy compared to contrast sample. As a result of this study, it indicates that both AR and CYR has generally increased in their length, weight, and the number of leaves at low level accumulated dose part 0.01~0.2 Gy. The size of cell, area of nucleus and density of cell for test sample has been observed quite similar to the ones from contrast sample through microscope. In conclusion, AR and CYR irradiated by ${\beta}$-rays have estimated that they are achieved a rapid growth at low level accumulated dose region corresponding to its radiation hormesis theory. Further studies need to confirm the correlation between the radiation hormesis and the growth of the plants.