• Journal of Radiation Industry
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• v.17 no.2
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• pp.199-207
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• 2023

Since seeds can be directly used as food resources as well as for crop cultivation or preservation of genetic resources, it is essential to develop high-quality seed processing technology to increase agricultural productivity. Seed treatment means processing technologies of seeds through physical or chemical treatment processes from after harvesting seeds to before sowing of seeds to improve germination and growth rate, durability, and immunity, etc. Since chemical seed treatment technology using pesticides or plant growth regulators has problems of environmental pollution and human toxicity, it is desired to develop an alternative technology. As a physical seed treatment method, various technologies such as ionizing radiation, plasma, microwave, and magnetic field are being developed, and some of them are being used practically. In this paper, I will summarize the mechanism of seed priming and disinfection, and the advantages and disadvantages of application, focusing on these physical seed treatment methods. Low dose or moderate intensity ionizing radiation, microwave, low-temperature plasma, and magnetic field treatments often promoted seed germination and seedling growth. However, effective removal of direct seed pathogens at these treatment intensities appears to be difficult. And it has been shown that relatively high-dose electron beam treatment using low-energy electron beams kills microorganisms on the seed surface and hull layer while not damaging the inner tissue of the seed, and is also effectively used for seed treatment on a commercial scale. In order to put the physical seed treatment technology to practical use in Korea, it is necessary to develop an economical scale treatment device along with the development of individual treatment technology to each crop.

• Research in Plant Disease
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• v.19 no.4
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• pp.254-258
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• 2013

Fusaric acid (FA) is a mycotoxin produced by Fusarium species. Its toxicity is relatively low but often associated with other mycotoxins, thus enhancing total toxicity. To date, biosynthetic genes or enzymes for FA have not been identified in F. oxysporum. In order to explore the genetic element(s) for FA biosynthesis, restriction enzyme mediated integration (REMI) procedure as an insertional mutagenesis was employed using FA producing-F. oxysporum strains. Genetic transformation of two F. oxysporum strains by REMI yielded more than 7,100 transformants with efficiency of average 3.2 transformants/${\mu}g$ DNA. To develop a screening system using phytotoxicity of FA, eleven various grains and vegetable seeds were tested for germination in cultures containing FA: Kimchi cabbage seed was selected as the most sensitive host. Screening for FA non-producer of F. oxysporum was done by growing each fungal REMI transformant in Czapek-Dox broth for 3 weeks at $25^{\circ}C$ then observing if the Kimchi cabbage seeds germinated in the culture filtrate. Of more than 5,000 REMI transformants screened, fifty-three made the seeds germinated, indicating that they produced little or fewer FA. Among them, twenty-six were analyzed for FA production by HPLC and two turned out to produce less than 1% of FA produced by a wild type strain. Sequencing of genomic DNA regions (252 bp) flanking the vector insertion site revealed an uncharacterized genomic region homologous (93%) to the F. fujikuroi genome. Further study is necessary to determine if the vector insertion sites in FA-deficient mutants are associated with FA production.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.4
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• pp.265-273
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• 2001

The sea urchin has been used as sea food in many countries. This species has also been an important organism of embryological studies for more than a century. In recent years, sea urchin embryos are being used as testing materials for toxicity of pollutants and toxins. Usefulness of sea urchin embryos as experimental models comes from the easiness in obtaining sea urchin samples and a lot of gametes, in rearing embryos in the laboratory, in observing the cellular movement and organ formation during the embryogenesis and in manipulating blastomeres and genetic maferials. The sea urchin in itself is a key organism for the understanding of deuterostome evolution from the protostomes and of indirect development of marine invertebrates which undergo the planktotrophic larval stage. A fertilized sea urchin egg goes through rapid cleavage and becomes a 60 cell embryo 7hr after fertilization. It then develops into a morula, a blastula, a gastrula and finally a pluteus larva approximately 70 hr after fertilization. At the 60 cell stage, the embryo comprises of five territories that express territory-speciflc genes and later form different organs. Micromeres at the vegetal pole ingress into the blastoceol and become the primary mesenchyme cells(PMCs). PMCs express genes involved in skeletogenesis such as SM30, SM37, SM50, PM27, msp130. Among the genes, SM37 and SM50 are considered to be members of a gene family which is characterized by early blastula expression, Glycine-Proline-Glutamine rich repeat structures and spicule matrix forming basic proteins. Genetic studies on the sea urchin embryos help understand the molecular basis of indirect development of marine invertebrates and also of the biomineralization common to the animal kingdom.

• Korean Journal of Ecology and Environment
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• v.35 no.3 s.99
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• pp.198-212
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• 2002

A numerical variation and abnormalities were studied on egg bags and embryos of Korean salamander, Hynobius leechii from agricultural habitat. The teratogenic and toxic effects of fungicide benomyl were also investigated with early embryos from non-agricultural habitat. We collected 144 egg bags from agricultural region, and 3418 of early embryos were contained. The lengths of egg bags were varied from 10 to 23 cm and the most frequent length was 19 cm. The number of embryos was varied from 7 to 43, and the most frequent range was 22 to 26. Spontaneous abnormalities were occurred in 406 embryos among 116 egg bags, and 24 kinds of external abnormalities were found. Individuals showing severe external defect were histologically studied and they showed optic dyspalsia, thyroid carcinoma, somatic muscular dysplasia, partial biaxial structure, decrease of red blood cells in the heart, cephalic degeneration and intestinal dysplasia. 385 embryos from non-agricultural region were exposed to 200 nM${\sim}$ 1 ${\mu}$M of benomyl at blastula or gastrula for 12 days. All embryo were dead in the concentration of 1 ${\mu}$M (LD$_{100}$) and 75% of embryos were dead in 800nM of benomyl. Speciflc effect due to benomyl was acrania or cephalic dysplasia and this restult suggests that the benomyl inhibit stongly to the development of neural tissue. These abnormal developments may be caused by antimitotic action, inhibition of tubulin complex, destruction of microtubule, inhibitions of neurulation and closing of neural fold, and by the inhibition of the movement of neural crest cells.

• BMB Reports
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• v.40 no.5
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• pp.773-782
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• 2007

Different isolates of the soil bacterium Bacillus thuringiensis produce multiple crystal (Cry) proteins toxic to a variety of insects, nematodes and protozoans. These insecticidal Cry toxins are known to be active against specific insect orders, being harmless to mammals, birds, amphibians, and reptiles. Due to these characteristics, genes encoding several Cry toxins have been engineered in order to be expressed by a variety of crop plants to control insectpests. The cotton boll weevil, Anthonomus grandis, and the fall armyworm, Spodoptera frugiperda, are the major economically devastating pests of cotton crop in Brazil, causing severe losses, mainly due to their endophytic habit, which results in damages to the cotton boll and floral bud structures. A cry1Ia-type gene, designated cry1Ia12, was isolated and cloned from the Bt S811 strain. Nucleotide sequencing of the cry1Ia12 gene revealed an open reading frame of 2160 bp, encoding a protein of 719 amino acid residues in length, with a predicted molecular mass of 81 kDa. The amino acid sequence of Cry1Ia12 is 99% identical to the known Cry1Ia proteins and differs from them only in one or two amino acid residues positioned along the three domains involved in the insecticidal activity of the toxin. The recombinant Cry1Ia12 protein, corresponding to the cry1Ia12 gene expressed in Escherichia coli cells, showed moderate toxicity towards first instar larvae of both cotton boll weevil and fall armyworm. The highest concentration of the recombinant Cry1Ia12 tested to achieve the maximum toxicities against cotton boll weevil larvae and fall armyworm larvae were 230 ${\mu}g/mL$ and 5 ${\mu}g/mL$, respectively. The herein demonstrated insecticidal activity of the recombinant Cry1Ia12 toxin against cotton boll weevil and fall armyworm larvae opens promising perspectives for the genetic engineering of cotton crop resistant to both these devastating pests in Brazil.

• Korean journal of applied entomology
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• v.47 no.4
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• pp.435-445
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• 2008

Due to internal feeding behavior, the oriental tobacco budworm, Helicoverpa assulta ($Guen\acute{e}e$), infesting hot pepper has been regarded to be effectively controlled by targeting egg and neonate larval stages just before entering the fruits. This study aimed to develop an efficient biological control method focusing on these susceptible stages of H. assulta. An egg parasitoid wasp, Trichogramma evanescens Westwood, was confirmed to parasitize the eggs of H. assulta. A mixture of Gram-positive soil bacterium, Bacillus thuringiensis subsp. kurstaki, and Gram-negative entomopathogenic bacterium, Xenorhabdus nematophila ANU101, could effectively kill neonate larvae of H. assulta. A sex pheromone trap monitored the occurrence of field H. assulta adults. The microbial insecticide mixture was proved to give no detrimental effects on immature development and adult survival of the wasp by both feeding and contact toxicity tests. A combined treatment of egg parasitoid and microbial pesticide was applied to hot pepper fields infested by H. assulta. The mixture treatment of both biological control agents significantly decreased the fruit damage, which was comparable to the chemical insecticide treatment, though either single biological control agent did not show any significant control efficacy. This study also provides morphological and genetic characters of T. evanescens.

• Journal of Life Science
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• v.28 no.8
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• pp.931-937
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• 2018

Triptolide is a compound found in Tripterygium wilfordii and reported to have an anti-inflammatory and anti-oxidant activities. A previous study shows that the dietary supplementation with triptolide increases resistance to environmental stressors, including oxidative stress, heat shock, and ultraviolet irradiation, and extends lifespan in C. elegans. Here, we investigated the underlying mechanisms involved in the lifespan-extending effect of triptolide. The effect of triptolide on age-related diseases, such as diabetes mellitus and Alzheimer's disease, was also examined using animal disease models. The longevity phenotype conferred by triptolide was not observed in the eat-2 mutant, a well-known genetic model of dietary restriction, while there was an additional lifespan extension with triptolide in age-1 and clk-1 mutants. The long lifespan of age-1 mutant is resulted from a reduced insulin/IGF-1-like signaling and the clk-1 mutant lives longer than wild-type due to dysfunction of mitochondrial electron transport chain reaction. The effect of dietary restriction using bacterial dilution on lifespan also overlapped with that of triptolide. The toxicity of high glucose diet or transgenic human amyloid beta gene was significantly suppressed by the supplementation with triptolide. These findings suggest that triptolide can mimic the effect of dietary restriction on lifespan and onset of age-related diseases. We conclude that triptolide can be a strong candidate for the development of dietary restriction mimetics.

• Environmental Analysis Health and Toxicology
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• v.18 no.2
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• pp.121-129
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• 2003

The genotoxicity of pendimethalin [N-(l-ethylpropyl)-2, 6-dinitro-3, 4-xylidine, C$\_$13/H$\_$19/N$_3$O$_4$, M.W.=281.3, CAS No. 40487-42-1], one of selective herbicide, was evaluated in bacterial gene mutation system, chromosome aberration in mammalian cell system and in vivo micronucleus assay with rodent. In bacterial gene mutation assay, pendimethalin revealed dose-dependent mutagenic potential in 313 ∼ 5,000 ${\mu}$g/plate of Salmonella typhimurium TA 98 and TA 1537 both in the absence and presence of S-9 metabolic activation system, and TA 100 only in the absence of S-9 mixture. In the TA 1535, slight increase of revertant was also observed in the presence of S-9 metabolic activation system. No mutagenic potential was observed in the TA 1535 without metabolic activation system and TA l00 in the presence of S-9 mixture. In mammalian cell system using Chinese hamster lung (CHL) fibroblast, no clastogenicity of pendimethalin was observed both in the absence and presence of S-9 metabolic activation system in the concentration range of 2.32∼9.28 ${\mu}$g/ml. And also, in vivo bone marrow micronucleus assay, pendimethalin revealed no clastogenic potential in the dose range of 203∼810 mg/kg body weight after oral administration in mice. Consequently, in vitro chromosome aberration with mammalian cells and in vivo bone marrow micronucleus assay revealed no clastogenic potential of pendimethalin. However, pendimethalin revealed mutagenic potential in bacterial gene mutation assay.

• Journal of Food Hygiene and Safety
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• v.16 no.2
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• pp.145-151
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• 2001

EpoxidiBed soy bean oil (ESBO) is a plasticizer of PVC which is being widely used as a gaskets for the lid of glass jars including baby food. Using reverse mutation assay, chromosome aberration test and micronucleus test, ESBO were evaluated the mutagenicity. In the reverse mutation test, ESBO did not induced mutagenicity in Salmonella typhimurium TA98, TA100, TA1535, TA1537, TA102 with and without metabolic activation. In the chromosome aberration test using CHL cells, the results showed no increased structural and numerical aberrations in the concentration of sample producing cytotoxicity with and without metabolic activation. The in vivo induction of micronuclei was measured in polychromatic erythrocytes of bone marrow of young (3weeks old) and adult (6 weeks old) ddY mice of both sex. At 24 hours after treatment with ESBO 20, 10, 5, 2.5 g/B.W. kg/corn oil 10 ml by oral route animals were sacrificed and bone marrow cells were prepared for smear slides. The results showed no increased micronucleated polychromatic erythrocytes regardless of sex and age. It was concluded that water soluble ESBO did not show certain genotoxicity within our studies conducted.

• Journal of Food Hygiene and Safety
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• v.13 no.4
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• pp.388-393
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• 1998

Recently there has been an increasing amount of foreign livestock products distributed in the domestic market due to the market opening. Some vicious dealers sell the foreign beef in the trade name of the native beef during the final distribution step to arouse the social criticism frequently. In this report, we investigated a method to distinguish the native beef from the foreign one scientifically using the PCR-RAPD, a recent gene technique. Hygienical safety was also examined using a microbiological test for toxicity of Escherichia coli 0157:H7 and the food poisoning bacteria. The conditions of DNA amplification for the PCR analysis were $1{\times}Taq$ polymerase buffer, 1.5 mM $MgCl_2,\;50\;\mu\textrm{M}$ dNTP, 100 ng primers, 2.5 unit Taq polymerase and 5~20 ng template DNA, with the fmal volume of $50\;\mu\textrm{\ell}$. The size of the amplified product was detected mostly in the range of 0.5~2.0 kbp. The size of DNA, gene marking factor, which could be a criterion distinguishing the native beef from the foreign one, appeared approximately 1.2 kbp. The native beef was distinguished from the foreign beef with more than 90% of confidence by the gene marking factor. This method was expected to be useful in the breed discrimination between the native beef and the foreign one. The hygienical test results showed that, fortunately, neither Salmonella spp. and Listeria monocytogenes which form a principal cause of the food poisoning nor Enterohemorrhagic Escherichia coli : EHEC which have provoked a recent social disturbance, were detected at all.