• Journal of Radiation Industry
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• v.7 no.1
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• pp.29-35
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• 2013

Microbiological populations and the sterility of commercial powdered products treated with gamma irradiation at 0~10 kGy were investigated before using them as ingredients for a non-cooked Saengsik product. We evaluated a total of 14 powdered products: 8 powdered cereals, 3 powdered tubers, and 3 powdered leafy vegetables. The total numbers of bacterial populations in non-irradiated powdered cereals, tubers, and leafy vegetables were 2.7~6.9, 5.6~6.0, and $5.3{\sim}6.8\;log\; CFU{\cdot}g^{-1}$, respectively. Moreover, coliform bacteria were not indicated in adlay, millet, germinated brown rice, soybean, and mulberry leaves powder within detection limit ($2.0\;log\; CFU{\cdot}g^{-1}$). The number of Bacillus cereus exceeded $3.0\;log\; CFU{\cdot}g^{-1}$ (the maximum limit for Saengsik products) in all samples, excluding perilla seeds, buckwheat, barley, oat, potato, and Jerusalem artichoke powder. However, a dose of 6 kGy of gamma irradiation reduced the microbiological populations in all samples, and all the powdered products met the microbial requirements for Saengsik products. Futhermore, it was confirmed that all microorganisms in the 9 powdered products, except fermented brown rice, sweet potatoes, and 3 leafy vegetables, were sterilized by 10 kGy of gamma irradiation.

• Journal of Radiation Industry
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• v.7 no.2_3
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• pp.135-139
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• 2013

Recently, chronic gamma radiation exposure on biological effects in middle dose-rates have become a serious concern. We investigated the biological effects of middle dose chronic exposure to gamma ray. Fifty male 6-week-old specific free Balb/c mice were randomly divided into five groups (four groups irradiated and one non-irradiated control group). Gamma radiation exposed in Gamma phytotron on Advanced Radiation Technology Institute (Jeongeup, Korea). Irradiation was carried out for 1 or 2 weeks using gamma rays at dose rates of 45 and $50mGy\;h^{-1}$ with total doses 7.56 Gy ($45mGy\;h^{-1}$, 1 week), 8.4 Gy ($50mGy\;h^{-1}$, 1 week), 15.12 Gy ($45mGy\;h^{-1}$, 2 weeks) and 16.8 Gy ($50mGy\;h^{-1}$, 2 weeks). After irradiation, immediately we sacrificed and counted body and organ weights. Moreover we counted spleen cell numbers. Compared with control non-irradiated group, all irradiated groups of body and spleen weights showed significant decreased. However, no significant alteration was observed between same irradiated period groups. In spleen cell numbers, reduced compared to the control group. However, significant alteration was observed between same irradiated period groups ($45mGy\;h^{-1}$, $50mGy\;h^{-1}$). These results demonstrated biological effects according to the radiation dose rate and irradiated period.

• Journal of Radiation Industry
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• v.8 no.2
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• pp.89-95
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• 2014

This study was conducted to determine the optimal dose of gamma-ray on the growth and nucleus DNA damage for mutation breeding in licorice. Gamma-rays irradiated to dry seeds with various doses (0 to 1000 Gy). Significant decreases in germination rate (%), survival rate (%) and growth characteristics (plant height, number of leaves, root length and fresh weight) were observed by dose of increased. $LD_{50}$ (lethal dose) was approximately 400 Gy to 500 Gy. Also, reduction doses ($RD_{50}$) of plant height, number of leaves, root length and flash weight were 428 Gy, 760 Gy, 363 Gy and 334 Gy, respectively. It is supplest that the optimal dose of gamma irradiation for licorice mutation induction might be about 400 Gy in this study. We also conducted comet assay to observe nucleus DNA damage due to gamma irradiation. In comet assay, a clear difference was identified over 300 Gy treatments. With increasing doses of gamma-ray in the range of 100 to 1000 Gy, the rate of head DNA was decreased significantly from 92.88% to 73.09%. Tail length(${\mu}m$) was increased as the dose of increased over 300 Gy. Growth characteristics (Germination rate, Survival rate, plant height, number of leaves, root length and fresh weight) were highly negatively ($P{\leq}0.01$) correlated with dose. While the tail length was highly positively ($P{\leq}0.01$) correlated with dose.

• Journal of Radiation Industry
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• v.6 no.2
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• pp.189-197
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• 2012

This study was carried out to develop the improved useful mutants for yield or composition of stevia plants using the gamma ray or chemical mutagens treatments. The seeds of stevia 'Suwon No. 11' were irradiated up to 400 Gy of gamma ray. Chemical mutagens were treated on the seeds of the 'Suwon No. 11' using 0.07% colchicine, 10 mM sodium azide, or 10 mM NMU for various durations. The germination rate, and shoot and root growth of seedling were estimated at 30 days after gamma ray irradiation or chemical mutagen treatment, and the plant height, the number of branches, and leaf length and width were examined at 3 months after mutagenesis treatments. In the case of gamma ray treatments, the germination rate and early-stage growth were decreased as the increase of radiation dose, and the 50% lethal dose was found to be 200 Gy. the plant height was decreased as the increase of radiation dose, while the number of branches per plant and leaf length were increased. Leaf shape was modified to the relatively longer one compared to the control, which was identified more apparently at the treatments of higher than 150 Gy. In the treatment of chemical mutagens, the rate of germination and survival were decreased as the increase of incubation time. The 50% lethal dose for germination rate were identified as the conditions of the 15 hours incubation in 0.07% colchicine, the 4 hrs in 10 mM sodium azide, and the 2 hrs in 10 mM NMU, in the three chemical mutagens treatments. Chemical mutagens had no influence on shoot growth, while root growth was increased, especially as the incubation time was extended. The highest root growth occurred in the NMU treatment at 6 hrs incubation time. The plant height was decreased as the increase of incubation time in the chemical mutagens treatments. Among the chemical mutagens, NMU was the most effective to induce the mutants with long-shaped or the least lobed leaves.

• Journal of Radiation Industry
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• v.5 no.3
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• pp.211-220
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• 2011

This study was carried out to develop salt tolerant varities of rapeseed (Brassica napus L.) which can be grown in the high salty reclaimed land. The seeds of three varieties 'Naehan', 'Tammi', and 'Halla' were treated by proton ion beams and gamma rays with 0 to 2,000 Gy. For the selection of salt tolerant lines, emergence and survival rate, and growth characteristics of $M_2$ to $M_4$ generations were investigated in the Saemangeum reclaimed fields with the different salt concentrations. The lines with potential salt tolerance were selected in the $M_4$ generation and tested indoor for their growth characteristics. There was no significant changes in the soil pH for $M_4$ generation during growth period. However, soil EC was higher in early spring than sowing period (mid October). In $M_4$ generation test, the seeds of original and selected line showed high rates of emergence and survival, as determined one month after sowing. After wintering, however, the original varieties showed the significant reduction in the survival rate, while the selected lines showed a higher survival rate and good growth, leading to the completion of their life cycle. Consequently we selected 9 lines from $M_4$ generation with better performance in growth and yield. Soil EC was $2.8{\sim}4.3dS{\cdot}m^{-1}$ during $M_4$ generation growth period. The laboratory test of the lines selected from $M_4$ generation was made for their salt tolerance potential. The selected lines showed higher chlorophyll and proline contents than the original varieties. There was also no significant difference in the emergence rate of seed between the original and selected varieties. In 200 mM natural sea salt, the $N{\gamma}600-21-1-641$ line derived from 'Naehan' was the highest in growth rate, leaf chlorophyll and proline contents. $T{\gamma}800-20-2-461$ line derived from 'Tammi' didn't show significant difference in growth rate compared to original variety in 200 mM and withered in 250 mM like other lines as time passed. $H{\gamma}200-7-1-740$ line showed similar growth and chlorophyll content compared to its original variety.

• FLOWER RESEARCH JOURNAL
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• v.16 no.2
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• pp.128-133
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• 2008

This study was conducted to select new variants with different characteristics in plant height, leaf color, and petal color of plantain lily (Hosta plantaginea) and Japanese farfugium (Farfugium japonicum). After 10-30Gy ${\gamma}-ray$ irradiation to seeds of both species, seed germination, variant induction, growth of variants, and survival ratios were estimated. Days required for seed germination were lengthened and % seed germination decreased as the dosage of ${\gamma}-ray$ increased over 20Gy. Lethal dose ($LD_{50}$) for plantain lily and Japanese farfugium were 30Gy and 25Gy, respectively. Plantain lily and Japanese farfugium treated by more than 20Gy ${\gamma}-ray$ showed dwarf characteristics in growth, and variations in leaf and petal colors. Total 166 variants in plantain lily were induced by ${\gamma}-ray$ irradiation in a $M_1$ generation, among which 12 promising variants were selected in a $M_2$ generation. Total 57 variants of Japanese farfugium were induced by ${\gamma}-ray$ irradiation in a $M_1$ generation, among which nine promising variants were selected in a $M_2$ generation.

• Korean Journal of Breeding Science
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• v.40 no.3
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• pp.303-307
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• 2008

We bred a new green-kerneled glutinous rice variety that can be cultivated in the whole area of Korea, because only one native green-kerneled glutinous rice cultivar, "Saengdongchalbyeo", has been cultivated in the southern coastal area due to its late heading. The seeds of "Saengdongchalbyeo" were irradiated with 200 Gy of gamma ray in 1995. A promising mutant variety, "Nogwonchalbyeo" ("Wonnong 17") was selected through line selection and regional yield trials. In particular, the new variety revealed at the earlier mid of August compared to that of "Saengdongchalbyeo", the early of September, and it was considerably tolerant to a field lodging due to its shortened culm length. Also, "Nogwonchalbyeo" had a higher ripened grain ratio and 1,000 grain weight compared to the original variety. The brown grain yield of the new variety was about 5.40 MT/ha, which was 11.3% higher than that of the original variety, in the regional yield trials at 3 different fields during 2000~2001. The brown and milled grains of the new rice variety contained 20 to 65% higher amount of total amino acids, respectively than that of the original and two checks. For chlorophyll -a, -b and total chlorophyll, the new variety showed nearly two-fold higher than the checks, and for the carotenoid, it had 5.3 - 7.6 times higher amount. These results showed that the new variety can be cultivated as a special green-kerneled glutinous rice with high functional compounds.

• Polymer(Korea)
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• v.38 no.1
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• pp.69-73
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• 2014

In this study, polysaccharide-poly(vinyl alcohol) (PVA) hydrogels were prepared by using ${\gamma}$-ray and evaluated for potential application as an anti-inflammation patch. Ulmus davidiana var. japonica (UD), one of polysaccharides has been particularly used as an oriental remedy for the treatment of inflammation and ulcers. PVA as a biocompatible polymer and glycerin as a moisturizer were blended with the UD, and its hydrogels were prepared by radiation crosslinking. Characterizations for UD hydrogels were performed by using cytotoxicity assay, antioxidant activity test, and physicochemical test such as gel fraction ratio, and swelling behavior. The results showed that these UD hydrogels had excellent physical properties, anti-inflammation activity, and non-cytotoxicity on the cells. Therefore, these polysaccharide based-UD hydrogels can be effectively used as an inflammation patch.

• Korean Journal of Breeding Science
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• v.42 no.3
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• pp.222-225
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• 2010

'Seoritae' is a very famous variety of black soybean for mixed cooking with rice in Korea. However, it has a couple of bad traits such as late flowering and maturity. To improve these characteristics, seeds of original 'Seoritae' were irradiated using a 250 Gy gamma ray in 1994. Some mutants were identified and finally a new soybean variety 'Josaengseori' was developed in 2005. This variety has a few distinguishable characteristics such as smaller grain size, early maturity and high yielding compared to the 'Seoritae'. The flowering period of 'Josaengseori' is 57 days after seeding (DAS), which is 10 days earlier than that of 'Seoritae' (67 DAS). The maturation period of 'Josaengseori' is 130 DAS, which is 34 days earlier than 'Seoritae' (164 DAS). And the total yield of the new variety with 179 kg/10a is 2.4 times higher than that of 'Seoritae' with 74 kg/10a. 100 grain weight of 'Josaengseori' is 32.8 g, which is 20% lower than that of 'Seoritae' with 40.1 g.

• Journal of Food Hygiene and Safety
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• v.33 no.6
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• pp.488-494
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• 2018

To ensure food-safety of mushrooms from radioactive contamination, edible mushroom samples distributed in Gyeonggi province in Korea were collected according to species and country of origin. A total of 284 mushrooms, belonging to 10 species (Lentinula edodes, Pleurotus ostreatus, Pleurotus eryngii, Agaricus bisporus, Flammulina velutipes, Phellinus linteus, Inonotus Obliquus (Chaga), Auricularia auricula-judae, Ganoderma lucidum and Tricholoma matsutake) were subjected to radioactivity testing. The concentration of artificial radionuclides, 131I, 134Cs, and 137Cs, was analyzed using gamma-ray spectrometry. 131I and 134Cs were not detected more than MDA value from all samples. Among 204 domestic mushrooms, however, 137Cs were detected in 0.21~2.58 Bq/kg from six cases (3 Lentinula edodes, 1 Ganoderma lucidum and 2 Tricholoma matsutake), whereas 137Cs were detected in 0.21~53.79 Bq/kg from 38 cases (22 Inonotus Obliquus(Chaga), 14 Phellinus linteus, 1 Lentinula edodes and 1 Tricholoma matsutake) among 80 imported mushrooms. In addition, average concentration of 137Cs in 10 Chaga mushroom-processed products was more than twice as much as dried Chaga mushroom, and maximum concentration was 123.79 Bq/kg. Results suggest that radioactivity monitoring system for imported mushrooms and mushroom-processed products should be continuously intensified to secure food-safety in Korea.