• Journal of Microbiology and Biotechnology
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• v.11 no.2
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• pp.342-345
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• 2001

A bacterial strain PH-4, which produces an enzyme catalyzing the degradation of crosslinked poly(${\gamma}$-glutamic acid) hydrogels, was isolated and identified as a Flavobacterium sp. The enzyme was obtained by the sonication of the bacterial cells preincubated in a Bouillon medium with shaking, without adding of poly(${\gamma}$-glutamic acid) as an inducer. The products of the hydrogel degraded by the crude enzyme agreed closely with the depolymerized materials in SDS-polyacrylamide gel electrophoresis using methylene blue staining, and with a glutamic acid monomer on thin-layer chromatography, thereby suggesting that strain PH-4 produced a kind of exohydrolase.

• Preventive Nutrition and Food Science
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• v.11 no.2
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• pp.146-154
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• 2006

Structural modification of corn starch by gamma irradiation was evaluated for under dry conditions at varied intensities from 0 to 40 kGy. Under scanning electron microscopy, the granule shape of corn starch was not significantly affected by the irradiation up to 40 kGy. In addition, X-ray diffraction and melting patterns of the irradiated starches were similar to those of the native starch, indicating that crystalline regions in the starch granules were not changed by irradiation. However, the pattern of gel permeation column chromatography showed a significant increase in partial hydrolysis of gamma irradiated starch samples. The degree of polymerization and the paste viscosity of irradiated starch samples dose-dependently decreased significantly with irradiation, and increased solubility and clarity were observed in the irradiated starch solution. In addition, the degree of retrogradation decreased as irradiation dose increased. Irradiation of corn starch has advantages over the ordinary acid or the enzyme hydrolysis modification methods. It does not affect the granular shape and crystalline phase of starch during hydrolysis, and the process can be carried out in dry state.

• Journal of radiological science and technology
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• v.15 no.1
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• pp.123-130
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• 1992

This study was prepared to observe the change of enzyme activities in kidney treated with red ginseng extract in the gamma ray irradiated mice. Determine the activity of SOD, peroxidase, catalase in the kidney a period of 1 day, 2 day, 3 day, 4 day, 5 day after a saline injection or injection of red ginseng extract or gamma ray irradiatied group into four classify. The activity SOD and catalase showed a tendency to increase and recovery at the early state but pay no regard. Wherease, the activity of peroxide restored and increased pay regard. A physiological saline injection group after gamma ray irradiation showed a tendency to diminish after remakable increase of activity of SOD, peroxidase and catalase than control group. Injection group of red ginseng extract after gamma ray irradiation observed rapid recovery on activity of SOD, peroxidase, catalase than a saline injection group. Experimental result suggested that injection of red ginseng extract after irradiation have the recovery effect on the changed of activity of SOD, peroxidase and catalase against radiation injury.

• Journal of Life Science
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• v.16 no.2 s.75
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• pp.180-185
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• 2006

We investigated relations between physiological damages and gene expression and enzyme activities of superoxide dismutase(SOD) isoenzymes in leaves of rice (Oriza sativa L. cv. Ilpoombyeo) plants irradiated with a high-dose gamma-ray. Gamma-irradiation with 500 Gy caused significant decreases in the contents of protein, chlorophyll and carotenoid in the rice leaves by 24 h, especially reducing the chlorophyll contents up to 26% relative to the control. In contrast, gene expressions of SOD isoenzymes were kept higher in the irradiated leaves until 24 h after the irradiation than in the control and they started to noticeably decrease at 48 h, finally being lower in the irradiated leaves at 72 h than in the control. In the case of enzyme activities of SOD isoenzymes, some CuZn-SOD isoenzymes showed slightly increased activities until 48 h after the irradiation but at 72 h, all isoenzyme activities markedly decreased in the irradiated leaves below the control levels. In conclusion, 500 Gy gamma-irradiation used in the current study caused decreases in the contents of protein, chlorophyll and carotenoid as symptoms for physiological damages. Although such physiological damages were not directly related to the gene expressions and enzyme activities of SOD isoenzymes until 24 h after the irradiation, the damages at 72 h were reasonably attributable to their reduction.

• Journal of radiological science and technology
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• v.13 no.1
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• pp.29-35
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• 1990

In a attempt to find out the effects of the irradiation on the lymphatic organs of birds, a total of 40 chickens(4 week old) were selected at random and alloted to control and experimental groups. The experiments were irradiated Co-60 ${\gamma}-ray/400$ rads, and then the enzyme histochemical activity of Bursa Fabricious(BF), thymus and spleen and hematological changes were compared with those of controls for 30 days(24 hrs., 5, 10, 20 and 30 days). The results obtained were summarized as follows: 1. The activity of acid phosphatase(ACP) of the reticuloendothelial cells of BF, thymus and spleen and the epithelia of BF of the experiments were increased significantly from the early experimental terms and then returned to the same level of controls through the late experimental terms. 2. The activity of nonspecific esterase(NSE) of the constituent cells with exception of the lymphocytes in BF, thymus and spleen of experiments were increased significantly from the early experimental terms and then returned to the same level of control through the late experimental terms. 3. The lymphocyte percentage, total erythrocytes and homoglobin of the experiments were severely decreased from early experimental terms and then increased to the normal levels of them incontrols.

• Korean Journal of Environmental Agriculture
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• v.19 no.2
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• pp.142-146
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• 2000

To observe the stimulating effects of low dose ${\gamma}-radiation$ on the seed germination, early growth and physiological activity in the gourd, seeds of three cultivars (Partner, Support, FR Yongja) were irradiated at the dose of $0.5{\sim}30\;Gy$. The hormetic effects of the low dose ${\gamma}-radiation$ on the growth were different from each cultivar. Low dose ${\gamma}-radiation$ had promoting effects on the germination at the optimum dose of 2 Gy and 8 Gy and on the early growth at the optimum dose of 4 Gy, 16 Gy and 20 Gy in Partner and Support cultivar and 1 Gy in FR Yongja cultivar. Irradiation didn't have significant effects on the chlorophyll contents of gourd plantlet. The antioxidant enzyme activity of gourd plantlet and early growth increased in low dose irradiation group.

• Journal of radiological science and technology
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• v.8 no.2
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• pp.47-63
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• 1985

This paper was aimed to study the effects of Cobalt-60 gamma ray irradiation on Albino rat blood cells and the activity of enzymes were measured using blood cell auto analyzer (Cell-Dyn 900) and enzyme autoanalyzer (Gilford 3500) respectively. Cobalt-60 gamma rays those are grouped into 200R, 400R, 600R, 800R, 1,000R, 1,200R, 1,300R, 1,400R, 1,500R and 1,600R to the rats of male and female and measured the numeral varieties of blood corpuscles of the rats and the active varieties of enzyme of acid, alkaline phosphatase (ACP, ALP), lactic acid dehydrogenase (LDH), glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase. (GPT) those came out after 1, 3, 5 or 7 days. The results are summarized as follows: 1. In both case of male and female, the numeral varieties of the erythrocytes, in the 200R group of irradiation showed the minimum value in the 3 days group and a tendency of increase in the 5 and 7 days groups, while the numeral varieties of the leucocytes in every groups of irradiation showed a tendency of a rapid decrease after a day. The numeral varieties of the blood platelet in both case of male and female didn't show generally any great change in a day and 3 days groups, but showed a rapid decreasing appearance after the 5 days. 2. In both case of male and female, the activities of ACP were on the decrease gradually after 3 days of the irradiation and the activities of ALP were on the decrease after 5 days. Similarly in both case of mate and female, the activities of LDH showed the decrease after 3 and 5 days, and the phenomenous of GOT showed an appearance of increase in a day, but decreased after 3 days. As for the GPT activities couldn't find any great change in the male rats in comparison with the control groups, but in the female rats a tendency of the increase in 600R, 800R, 1,000R groups after 3 days. 3. In the case of the irradiation of high quantity of ray more than 1,200R, all rats died after 4 days, and by the irradiation of 1,600R all rats died after 3 days, and it showed the sensitive response of a living body to the irradiation of high quantity.

• Applied Biological Chemistry
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• v.28 no.1
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• pp.28-35
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• 1985

Potato tubers treated at $4^{\circ}C$ for 4 weeks were irradiated with a dose of 0.12 kGy from $^{60}Co$ source and stored at $20^{\circ}C,\;70{\sim}90%$ humidity for 5 weeks. Changes of ${\alpha}-amylase$, peroxidase, indole acetic acid oxidase, indole acetic acid synthesizing enzyme activities were determined. In addition, treatment of gibberellin or indole acetic acid to tubers irradiated were carried out to examine reversal of sprout-inhibition of tubers irradiated. Results are as follows; 1. Irradiation by ${\gamma}-ray$ at 0. 12 kGy dose inactivated easily the enzyme activities in vitro. $D_{37}$ values obtained were 0.94, 0.36 kGy for ${\alpha}-amylase$ and peroxidase, respectively 2. Complete inhibition of the toter sprouting was resulted by the irradiation of tubers with a dose of 0.12 kGy. 3. The indole acetic acid oxidase activity increased 2 times immediately after irradiation. Meanwhile, indole acetic acid synthesizing activity decreased about $50{\sim}75%$ for 5-week storage in irradiated potatoes, whereas the activity increased about 3.5 times along with sprouting in non-irradiated tubers. 4. In morphological aspects, deformed buds with necrosis in the meristmatic tissue were developed in irradiated tubers. Treatment of gibberellin or indole acetic acid at the concentration of 100 or 20 ppm to the irradiated tubers reversed the sprout-inhibition partially. Nevertheless, the deformed buds remained without change.

• Korean Journal of Breeding Science
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• v.42 no.1
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• pp.1-10
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• 2010

Five mutants were investigated at the molecular level to determine the factors responsible for mutated endosperm types. They were classified as high (HA) or low amylose (LA) phenotypes based on the amylose content in endosperm. The five were previously produced from Ilpum and Shindongjin cultivar treated with N-methyl-N-nitrosourea and gamma-ray irradiation, respectively. Analysis of the genomic structure and expression of Granule-bounded Starch Synthase I (GBSSI) genes revealed that mutants generally showed a higher incidence of nucleotide transition than transversion, and the $A:T{\rightarrow}G:C$ transition was particularly prevalent. The rates of nucleotide substitution in HA mutants were generally higher than those in the LA mutants, leading to higher substitutions of amino acid in the HA mutants. Neither nucleotide substitutions interfering with intron splicing or causing early termination of protein translation were found, nor any large-sized deletions or additions were found in all the mutants. In principle, amylose content can be regulated by three factors: internal alterations of GBSSI protein, the strength of gene expression, and other unknown external factors. Our results indicate that the endosperm mutants from Shindongjin arose from internal alterations of GBSSI proteins, which may be the result of amino acid substitutions. On the other hand, the Ilpum mutants might be principally caused by the alteration of gene expression level. Analysis of another three glutinous cultivars revealed that the major factor leading to glutinous phenotypes is the 23-bp duplicative motif (5'-ACGGGTTCCAGGGCCTCAAGCCC-3') commonly found in exon 2, which results in the premature termination of protein translation leading to the production of a non-functional GBSSI enzyme.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1159-1163
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• 1999

Along with the increasing demands for food irradiation technology in the food industry, a proper detection means for controlling irradiated foods is required. Enzyme powder, which is permitted to be irradiated in Korea, was subjected to a detection trial by ESR spectroscopy. The high correlation coefficients were observed between the absorbed doses ranging from 2.5 to 15.0 kGy and the corresponding ESR signal intensity, such as $R^2$ = 0.9904 in gamma irradiation and $R^2$ = 0.9696 in electron beam. Pre-established threshold values for both non-irradiated control (1.19) and 2.5 kGy-irradiated samples (6.97 in gamma-ray; 7.36 in electron-beam) were successfully applicable to the detection of 30 coded unknown samples of enzyme powder. The calibration curves obtained from the samples irradiated at 2.5 to 15 kGy were expected to be potentially adopted to estimate absorbed doses ranging front 4 to 7 kGy with a quadratic equation.