A 5-day germination test is applicable to detect biological changes in irradiated wheat and barley at low doses. Seeds were irradiated at below 0.5 kGy, husked and placed on distilled water-moistend filter paper in a covered Petri-dish. Water was supplied everyday. To evaluate the growth rate, the length of shoots and roots was measured during germination. In wheat, the shoots of all samples grew well during 5 days, but the shoot length and the daily growth extent decreased with increasing doses. The roots of non-irradiated wheat showed the highest daily growth extent during 5 days and the root length was over 20 mm at 3rd day. In barley, the growth of shoots and roots was retarded at 0.3 kGy or more after 3 days. It was concluded that if the root length was 20mm or longer within 3 days, wheat and barley were identified as non-irradiated. The germination test was proved a promising screening method for the detection of irradiated wheat and barley.

The germination test was used to detect biological changes in irradiated rice and glutenous rice at low doses. Grains were irradiated at below 0.5 kGy, husked and placed on distilled water moistend filter paper in a covered petri-dish. A germination test of 20 grains was carried out at room temperature for 5 days. The shoots and roots of non-irradiated rites grew well in comparison with those of irradiated rites above 0.3 kGy. The roots of rites were more sensitive to irradiation than the shoots, and the growth of roots was significantly decreased with the increasing doses. In glutinous rites, the growth of shoots and roots was retarded by irradiation at 0.2 kGy or more after 3rd days. We concluded that if the shoot or root length is 10 mm or longer within 5 day, the rites and glutinous rites are identified as non-irradiated.

Microbial populations of total aerobic bacteria -and coliforming bacteria, TBA, Hunter's color value, heme pigments, muscle protein solubility, cooking loss and shear force were investigated for evaluating the shelf life of chicken legs gamma-irradiated at doses of 1, 3, 5 and 10 kGy with air-contained and vacuum-packaged methods. The initial microbial populations decreased with gamma irradiation depending upon the dose, and microorganisms in the vacuum-packaged samples were inhibited more than those in the air-contained samples. TBA values were higher in the air-contained samples than in the vacuum-packaged samples. Hunter's L and a values of the surface and inside of the legs increased by gamma irradiation, showing a bright red color and the red color was maintained during the storage of both samples. The concentrations of oxymyoglobin among the heme pigments increased by gamma irradiation. Muscle protein solubility slightly increased by increasing the applied dose. There were no significant differences in the cooking loss and shear force values. In conclusion, the combination of gamma irradiation and vacuum-packaging could extend the shelf life of chilled chicken without deterioration of the quality.

The effect of gamma irradiation on the survival of spore bacteria was investigated in frozen cells (-18℃) with 0.1 M phosphate buffer and inoculated cells in beef. In the case of the frozen cells at log phase, the radiation D_(10) and 12D_(10) values were 0.29 kGy and 3.48 kGy in Bacillus subtilis, 0.39 kGy and 4.68 kGy in Bacillus cereus and 0.46 kGy and 5.52 kGy in Clostridium perfrigens. And inactivation factors were 6.52-10.34 and 10.87-17.24 at the dosage of 3 kGy and 5 kGy, respectively. The radiosensitivity of inoculated cells in beef showed the D_(10) value of 0.59-0.76 kGy, the 12D_(10) value of 7.08-9.12 kGy, and inactivation factors of 3.95-8.47. The radiosensitivity of the frozen cells was higher than that of inoculated cells in beef.

Irradiated and non-irradiated Korean medicinal herbs were extracted by water and 70% ethanol. Antimicrobial activity of these extracts were investigated against selected food hygiene microoganisms. The ethanol extracts of the non-irradiated Agrimonia pilosa ledebour japonica Nakai, Curcuma longa Linne and Angelica gigas Nakai were completely inhibited on four species of bacteria, such as Vibrio parahaemolyticus, Clostridium perfringenes, Bacillus subtilis and Staphylococcus aureus. Also, above four strains did not have antibacterial activity in the water-ethanol mixtures. Futhermore, the ethanol extracts of the non-irradiated Agrimonia pilosa ledebour Japonica Nakai, Curcuma ledoaria Roscoe, Curcuma longa Linne and Scutellaria baikalensis George were shown inhibitory effects against Aspergillus flavus and Penicillium islandicum. And the water extract of Scutellaria baikalensis George was the same effect to these molds. Essentially the same results were observed when samples irradiated at a dose of 10 kGy.

D_(10) values obtained for radiation alone in Bacillus subtilis and Clostridium perfrigenes were 0.35-0.48 kGy in vegetative cells, and 2-2.08 kGy in spores, respectively. Irradiation dose of 24 kGy completely inhibited spores. In the case of heat treatment, D_(50, 60) values ranged from 10 to 14 minutes in vegetative cells, and D_(70, 80, 90), values ranged from 10 to 140 minutes in spores. In the case of combined treatment with heat and radiation, D_(10) values ranged from 1 to 1.25 kGy in vegetative cells, and from 3.42 to 3.61 kGy in spores. Thus, resistance of cells to gamma radiation did not seem to be influenced by pre-heating.

The yields of solvent fractions of irradiated red ginseng powder were increased in the order of petroleum ether(PE)$lt;diethyl ether(DE)$lt;ethyl acetate(EA)$lt;n-butanol (BU)$lt;aqueous fraction(AQ), and did not show any changes in fraction yields by irradiation dose levels. Inhibition activities of lipid peroxide formation were increased in the order of AQ$lt;BU $lt;PE$lt;EA$lt;DE. Inhibition activities of malonaldehyde formation were increased in the order of AQ≤BU$lt;EA$lt;PE$lt;DE. AQ fraction showed little effects on the antioxidative activity and all the activities of the samples did not changed by gamma irradiation. The reverse mutation assay using Salmonella typhunurium (TA98, TA100 and TA102) demonstrated that the nonirradiated and irradiated red ginseng powder extract did not have mutagenic activity (presence of S9 mix or not). The chromosomal aberration test in mammalian animal cell (Chinese hamster lung fibroblast, CHL) showed no significant increase in incidence of structural and numerical aberrations, comparing gamma-irradiated red ginseng powder extracts to nonirradiated red ginseng powder extract in the concentration of the sample producing cytotoxicity(presence of S9 mix or not). Therefore, gamma-irradiatied red ginseng powder (upto 10 kGy) could be safe on the genotoxic point of view.

궐련벌레(Lasioderma serricorne F)가 제품담배내 오염되었을때의 방제방법으로 감마선 이용법을 선전 방제효과를 조사하였다. Gelatin capsules에 공시충을 넣은 다음 감마선을 조사해 본 결과 0.8kGy이상의 선량에서 난태는 모두 살충되었고 용태나 성충때 및 유충태는 0~30%가 살충되었다. 몇가지 제품담배값내에 공시충을 함유한 gelatin capsules이 삽입된 궐련을 넣은후 감마선 조사시의 궐련벌레 충태별 방제효과도 동일한 결과를 얻었다. 감마선의 영향을 받은 궐련벌레의 성충 및 유충태를 인공먹이로 사육해 본 결과 차세대 개체군 증식이 확인되지 않았다. 감마선에 노출된 궐련벌레의 각 충태는 선량이 높아질수록 생존기간이 짧아졌으며 4령 유충이 처리 공시충중 가장 오래 생존하였다. 감마선에 노출된 제품담배의 고유향기나 맛은 선량 증가에도 영향을 받지 않았다. 감마선이 처리된 제품담배의 포갑지나 궐련지 및 은박지 등은 고유의 색도 또한 변화하지 않았다.

Background : Mutagenesis is one of the most powerful method for genetic variation, however there is little research history in P. ginseng. The seeds and vegetative tissues are materials commonly used for mutagenesis, but there is a problem that chimeras known as sectoral differences can occur and unintentional poor selection can occur owing to the influence of the growth environment. The combination of in vitro culture and mutagenesis can eliminate the effects of the environmental factors. Methods and Results : Gamma irradiation was carried out using a 60Co irradiator (3000Ci, Nordion Inc., Ottawa, Canada) of the Korea Atomic Energy Research Institute, Jeongeup, Korea. The explants containing the somatic embryos were treated with 20, 40, 60, 80, and 100 Gy. Gamma-rays affected the somatic embryos produced in vitro depending on the dose. The survival rate of somatic embryo was significantly influenced by gamma irradiation. Also, the development of the embryo was changed by gamma irradiation depending on each dose. When somatic embryos were transferred to the medium supplemented with GA3, they started to germinate but were affected significantly by gamma irradiation dose. When germinated shoots were transferred to 1/2 SH medium to induce rooting, as the concentration of gamma ray treatment increased, the rooting gradually decreased. Conclusion : Considering the overall survival rate, germination rate, embryo development, and rooting rate, the optimal dose of gamma rays to be used with somatic embryo is estimated to be between 60 Gy and 80 Gy.

Background : Panax ginseng C. A. Meyer is an important medicinal herb and their major pharmacologically active components are ginsenosides. Many studies have reported that various ginsenosides are effective in the treatment of human diseases such as cancer, cardiovascular and alzheimer’s disease. However, it is difficult to create new desirable variation such as increased ginsenosides. Since the frequency of spontaneous mutations is rare naturally and difficult to apply to plant breeding, artificial mutation inductions are necessary to obtain noble genetic resources having desirable traits. Methods and Results : Gamma irradiation was carried out using a 60Co irradiator (3000Ci, Nordion Inc., Ottawa, Canada) of the Korea Atomic Energy Research Institute, Jeongeup, Korea. One-year-old ginsengs were treated at 20, 40, 60, 80, and 100 Gy. The emergence rate was significantly decreased with increasing gamma doses. When irradiated at more than 80 Gy, it did not emerge at all. Survival rate was also significantly influenced by gamma-ray dose. The maximum survival rate were recorded in control. The survival rate of 20 Gy was 22.0% and only 1.0% survived when 40 Gy dose was treated. There was no survival when irradiated at more than 60 Gy. Gamma irradiation also affected the phenotype of emerged plants. The growth of plants derived from irradiated one-year-old ginsengs was decreased and the leaves became variegated or curled. Also, rusty roots resulting from physiological disorders were observed and the rhizomes, which is a kind of dormant bud, were destroyed completely. Conclusion : Based on these results, we estimated the optimal dose for mutation induction by gamma-ray treatment of one-year-old ginseng is to be less than 20 Gy.

Background : The conventional ginseng breeding is time-consuming and labor-intensive. Furthermore, it is difficult to create new desirable variation such as resistant to various stresses and increased ginsenosides. Therefore, creating variants remains a serious challenge of ginseng breeding. Methods and Results : Gamma irradiation was carried out using a 60Co irradiator (3000Ci, Nordion Inc., Ottawa, Canada) of the Korea Atomic Energy Research Institute, Jeongeup, Korea. The dehiscent seeds were treated 20, 40, 60, 80, 100, 120, 150, 200 and 400 Gy. The seed germination was greatly influenced by gamma-ray treatment. It was found that the germination rate decreased significantly when treated at 60 Gy or more. The maximum survival rate was achieved at 20 Gy but there was no significant difference from control. Following exposure to 40 Gy or more, survival rate was declined compared to the control. Gamma irradiation affected not only the germination and survival rate but also the growth of plants germinated from seeds. As gamma irradiation dose increased, the size of the plant decreased sharply and it also had a negative effect on root development. Conclusion : Considering the extent of reduction in the germination and survival rates, as well as growth reduction, the optimal dose of gamma-ray for inducing mutation in ginseng dehiscent seeds was estimated at approximately 40 Gy, because the germination rate observed at 40 Gy was similar to that of the observed in the control, while the survival rate was 50% of the control.

본 연구는 표준 감마선 조사장치의 유효빔 크기를 실측과 시뮬레이션의 결과를 비교하여 유효빔 영역의 결정에 유용한 수단을 제공하고자 하였다 시뮬레이션과 전리함을 이용한 실측의 결과는 공기커마율의 경우는 상대오차 4.5~7.3% 범위에 분포하였다. 유효빔 영역의 크기는 시뮬레이션의 경우 수평 방향 27cm, 수직 방향 21.6cm로 구현되었고, 필름을 이용한 실측결과는 수평 방향 26.5cm, 수직 방향 21.9cm로 유사한 결과가 도출되었다. 수평방향의 상대오차는 1.85%, 수직 방향은 1.38% 이며 유효빔 영역도 감마선장을 중심으로 유사하게 분포하였다. 감마선 조사장치에 있어서 시뮬레이션의 유효성이 충분함을 확인하였다. 특히 공기커마율보다 유효빔 크기의 상대오차가 적은 것은 빔의 크기가 표준선원의 용량보다는 기하학적 요인으로 결정되기 때문인 것으로 판단된다. 향후 시뮬레이션을 이용한 광자 에너지 분포도의 신뢰성을 높이기 위한 연구가 필요 할 것이다.

Background: The demand of recycling renewable agricultural by-products is increasing. Radiation breeding is a method used to improve saccharification efficiency. Thus, we investigated the effect of gamma ray irradiation on the pretreatment and enzymatic hydrolysis of the stalks of Senna tora, an important medicinal plants. Methods and Results: S. tora seeds were irradiated with gamma ray at doses of 100, 200, 300, and 400 Gy. In the pretreated biomass, glucan and lignin content were higher in the M1 (1st generations of irradiation) S. tora stalks than in the M2 (2nd generations of irradiation) stalks, this can be explained by the higher degradation rate in M1. After oxalic acid pretreatment, the concentration of total phenolic compounds (TPCs) in the hydrolysate increased in the gamma ray treated seeds. The highest relative increase rate in crystallinity in the pretreated biomass was observed in M1-400 Gy and M2-100 Gy. The cellulose conversion rate was higher in M1 than in M2, except for 200 Gy. Conclusions: Gamma ray irradiation at an appropriate dose can be used to improve the efficiency of pretreatment and enzymatic hydrolysis, thereby increasing biomass availability.