• Journal of Plant Biotechnology
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• 제45권1호
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• pp.55-62
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• 2018

In the present study in vitro mutagenesis was used to study the effect of gamma irradiation and EMS on callus induction, morphogenesis and production of multiple shoots from different explants of Citrullus colocynthis (L.) Schrad. Gamma radiations (5 kR to 20 kR) and certain chemicals have been effected on plant growth developments and changes of biochemical metabolisms in plants. Murashige and Skoog (MS) medium containing with auxins such as NAA, IAA, 2,4-D (0.5 ~ 2.0 mg/l), cytokinines BAP, kn TDZ, (0.5 ~ 2.5 mg/l), L-Glutamic acid (1 ~ 2 mg/l) and Coconut milk (10 ~ 20%). After 5 weeks on induction media, explants and callus (EC) were exposed to 5 kR, 10 kR, 15 kR and 20kR, of gamma radiation and treated with 1, 2, 3, 4 and 5 mM ethyl methane sulphonate (EMS) for 30 min. The highest percentage of callusing was observed (70%) stem irradiated with 5 kR and significantly decrease in fresh and dry weight of callus in the below 4 kR doses and above 20 kR doses, there was a progressive decrease in the fresh weight and dry weights when compared to control callus. Maximum percentage of plantlet regeneration (59%) was induced from callus exposed to 15 kR gamma irradiation on MS media fortified with 2.0 mg/l 2,4-D + 2.0 mg/l BAP + 2.0 mg/l L-glutamic acid. Increase in gamma irradiation dose above 15 kR and 5 mM EMS reduced regeneration capacity of callus. Doses higher than 20 kR and 7 mM EMS was lethal to micropropagated plants of Citurullus colocynthis.

• Korean Journal of Plant Resources
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• 제29권1호
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• pp.128-135
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• 2016

This study examined radiation damage and the optimal gamma-ray dose for mutation breeding in oat (Avena sativa L. cv. Samhan). The seed germination rate decreased as the dose increased over 500 Gy. The median lethal dose (LD₅₀) was approximately 392 Gy. The median reduction dose (RD₅₀) for plant height, tiller number, root length, and flash weight was 411, 403, 394, and 411 Gy, respectively. The optimal dose of gamma irradiation for inducing oat mutation appears to be in the range 300-400 Gy. We performed the comet assay to observe nuclear DNA damage induced by gamma-ray irradiation. This assay showed a clear difference with gamma-ray treatments. DNA damage increased temporarily 7 days after treatment depending on the dose, while no significant difference was identified in response to 300 Gy 30 days after the gamma-ray treatments. The growth characteristics of the M₂ generation decreased as the dose increased over 400 Gy.

• Polymer(Korea)
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• 제25권5호
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• pp.728-735
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• 2001

In this study, hydrogels from mixtures of chitosan/poly(vinyl alcohol) (PVA) and chitosan/poly(N-vinylpyrrolidone) (PVP) were prepared by ${\gamma}$-ray irradiation, and the mechanical properties such as gelation, water absorptivity and gel strength were examined to evaluate the applicability of these for wound dressing. The PVA : chitosan and PVP : chitosan ratio were in the range of 97:3 ~ 90:10, and the solid concentration of PVA/chitosan and PVP/chitosan solution were 15 wt%. Gamma irradiation with doses of 25, 35, 50, 60 and 70 kGy, was exposed to mixtures of PVA/chitosan and PVP/chitosan to evaluate the effect of irradiation dose. Gel content and gel strength increased as chitosan concentrations in PVA/chitosan and PVP/chitosan decreased, and as irradiation dose increased. Swelling degree increased as chitosan concentrations in PVP/chitosan and PVA/chitosan increased, and as irradiation dose decreased.

• Macromolecular Research
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• 제16권2호
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• pp.139-148
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• 2008

Biodegradable and elastic poly(L-lactide-co-$\varepsilon$-caprolactone) (PLCL) was electrospun to prepare nanofibers, and N-isopropylacrylamide (NIPAAm) was then grafted onto their surfaces under aqueous conditions using $^{60}Co-{\gamma}$ irradiation. The graft yield increased with increasing irradiation dose from 5 to 10 kGy and the nanofibers showed a greater graft yield compared with the firms. SEM confirmed that the PLCL nanofibers maintained an interconnected pore structure after grafting with NIPAAm. However, overdoses of irradiation led to the excessive formation of homopolymer gels on the surface of thc PLCL nanofibers. The equilibrium swelling and deswelling ratio of the PNIPAAm-g-PLCL nanofibers (prepared with 10 kGy) was the highest among the samples, which was consistent with the graft yield results. The phase-separation characteristics of PNIPAAm in aqueous conditions conferred a unique temperature-responsive swelling behavior of PNIPAAm-g-PLCL nanofibers, showing the ability to absorb a large amount of water at < $32^{\circ}C$, and abrupt collapse when the temperature was increased to $40^{\circ}C$. In accordance with the temperature-dependent changes in swelling behavior, the release rate of indomethacin and FITC-BSA loaded in PNIPAAm-g-PLCL nanofibers by a diffusion-mediated process was regulated by the change in temperature. Both model drugs demonstrated greater release rate at $40^{\circ}C$ relative to that at $25^{\circ}C$. This approach of the temperature-controlled release of drugs from PNIPAAm-g-PLCL nanofibers using gamma-ray irradiation may be used to design drugs and protein delivery carriers in various biomedical applications.

• Journal of the Korean Society of Safety
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• 제27권2호
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• pp.13-19
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• 2012

The effectiveness of treeing resistance in low density polyethylene containing azocompounds were investigated under radiation environments. 4-(4-nitrophenylazo)-1-naphthol and 4-(4-nitrophenylazo) resorcinol were selected for treeing inhibitors. LDPE containing the additives were crosslinked with dicumyl peroxide, irradiated by $Co^{60}$ ${\gamma}$-ray in the presence of air at room temperature. Treeing inception voltage, AC breakdown strength measurements were carried out for electrical insulation characteristics, thermoluminescence and gel contents were analyzed as various irradiation doses also. LDPE with treeing inhibitors showed much better insulation characteristics than pure LDPE. It is interpreted that molecular structures, polar groups and the type of radicals connected on the benzene ring of the additives affected electrical characteristics. From the results, 4-(4-nitrophenylazo) resorcinol was the most effective upon the best treeing and radiation resistance.

• Journal of environmental and Sanitary engineering
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• 제13권3호
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• pp.30-36
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• 1998

A study on the color removal by irradiation of ${\gamma}-ray$ was carried out to reclaim the secondary effluent for the purpose of industrial water. Coagulation, ozone and ion exchange methods were compared. It could know that irradiation method was the most effective in color removal. The color was removed by 87.5% at 0.5 Mrad and it was increase with dose. High removal efficiency could be obtained in low pH and low concentration of $CO3^{-2}$. This process can be applied to the treatment of secondary effluent and is considered to be one of the most useful tertiary treatment.

• International Journal of Oral Biology
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• 제36권3호
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• pp.149-154
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• 2011

In the present study, total methanol extracts prepared from Alpinia katsumadai showed significant protective effects against the oxidative stress induced by hydrogen peroxide, UV-C or ${\gamma}$-ray irradiation. These protective effects were substantially increased by treatment with 20~100 ${\mu}g$/ml of the extract. The A. katsumadai total methanol preparation was further fractionated into n-hexane, dichloromethane, ethylacetate, n-butanol and water fractions. Among these five fractions, the ethylacetate and butanol fractions of A. katsumadai showed the strongest protective effects against oxidative stress induced by UV-C and ${\gamma}$-ray irradiation. These fractions also showed high DPPH radical scavenging and lipid peroxidation inhibitory activities. In addition, both fractions displayed cell proliferation activation effects, as evidenced by significant increases in colony formation. Our current data thus suggest that the mechanisms underlying the protective effects of A. katsumadai against oxidative damage may include radical scavenging, protection against cell membrane damage and stimulation of cell proliferation.

• Korean Journal of Veterinary Research
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• 제42권2호
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• pp.183-190
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• 2002

The effects of ionizing radiation on the peripheral blood elements of ICR mouse were examined after varying doses of whole-body gamma-irradiation. ICR mice (n=50) were exposed to 0, 2, 4, 6 and 8 Gy gamma-ray ($^{60}Co$) at 10 Gy/min. The animals were studied for their hematological response on days, 3, 7, 14, 21, 42 and 56 post irradiation. No significant change was noted in erythrocyte, hemoglobin and hematocrit values after irradiation with dose of 2 Gy. Decreasing erythrocyte, hemglobin and hematocrit values occured after irradiation with doses of more than 4 Gy on day 7 after irradiation followed by a sharp fall on day 14. A recovery in these values was noted after 3 weeks of irradiation. Thrombocyte counts decreased on day 3, reaching minimal values on day 7. The total number of leukocytes was reduced on day 3, mainly because of a decrease in the lymphocyte population. An evident lymphopenia and neutropenia occur almost on the day 3 and last up to the day 28 after irradiation. All of the hematological values decreased in the blood in a dose-dependent manner at the same time.

• Asian Journal of Turfgrass Science
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• 제22권1호
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• pp.25-34
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• 2008

This study was conducted to determine the optimum dose ranges for a mutation breeding based on the observations of a seed germination and an early growth in turfgrasses. Three warm season (Zoysiagrass, Bermudagrass, and Seashore paspalum) and four cool season turfgrasses (Kentucky bluegrass, Tall fescue, Perennial ryegrass, and Creeping bentgrass) were used in this study. We investigated the percentage of a seed germination and a seedling growth after irradiating the turfgrass seeds with various doses of gamma-ray (50, 100, 150, 200, 250, 300, 400, and 500 Gy). After 24 h with a gamma irradiation, the seeds were sown on the wet filter paper in a petri dish and maintained for 3 weeks at 30$^{\circ}C$ for the warm season turfgrasses and at 25$^{\circ}C$ for the cool season turfgrasses. Data on a seed germination and a seedling growth with three replications were collected. The percentage of seed germination was decreased with an increase of the gamma-ray dose. Shoot and root growth, and the fresh weight were decreased significantly as the radiation dose was increased. A radiation dose indicating a 50% growth inhibition ($LD_{50}$) with a gamma irradiation was varied among those turfgrass species used, with the highest at about 500 Gy for bermudagrass and the lowest at 100Gy for tall fescue. The optimum dose for a gamma irradiation for a selection of turfgrass mutants was considered to be about 300, 150, 500, 150, 200, 100 and 200 Gy for zoysiagrass, seashore paspalum, bermudagrass, Kentucky bluegrass, perennial ryegrass, tall fescue, and creeping bentgrass, respectively.

• Journal of Radiation Industry
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• 제8권2호
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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.