• Korean Journal of Plant Tissue Culture
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• v.25 no.3
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• pp.153-158
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• 1998

The internal structures of Arabidopsis thaliana infected with beet curly top virus (BCTV) were studied by light microscopy. Hyperplasia was observed in the inflorescence stems of Arabidopsis thaliana ecotype Sei-O at 2 weeks after BCTV-Logan inoculation and callus was induced on symptomatic tissues at 4 weeks after virus inoculation. The infection processes were revealed as follows: hyperplasia of phloem tissue, necrosis of hyperplastic phloems, lacuna formation of necrotic tissues, elongation and enlargement of cortex and epidermal cells surrounding the lacuna formed phloem tissues, induction of cell division in the enlarged cortex and epidermal cells, and induction of callus tissue. Callus formation on Arabidopsis was caused by the virus infection, and virus inclusion body was observed in both phloem and callus tissue by azure-A staining.

• Journal of Marine Life Science
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• v.3 no.2
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• pp.96-100
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• 2018

Clonorchis sinensis is a main parasite that infects humans by making freshwater fish as an intermediate host in South Korea. There are so many reports about the infestation status of Clonorchis sinensis metacercariae (CsMc) in freshwater fish living in the river, but there are a few studies of fish in the lake. In this study, we examined CsMc in Cyprinid fish sampled from Soyang Lake, Namyang Lake, Andong Lake and Chunchun Lake from 2016 to 2017. Metacercaria of trematodes were found from Hemiculter eigenmanni and Carassius auratus in Namyang Lake, and Zacco platypus and Opsarichthys uncirostris in Soyang Lake. As a result of PCR using Clonorchis sinensis specific primer sets, it was confirmed that the metacercariae from Hemiculter eigenmanni in Namyang Lake was CsMc. This study provides information on CsMc infestation status of Cyprinid fish in four lakes and it is the first report of CsMc infestation in Namyang Lake.

• Parasites, Hosts and Diseases
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• v.34 no.1
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• pp.69-78
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• 1996

This study was done to investigate the enzyme-histochemical localization and characteristics of alkaline and acid phosphatase related with metabolism in sparganum and adult of Spirometrn erinacei. By the enzyme-histochemical assay, the alkaline and acid phosphatases were localized in the tegument and subtegumental musculature of sparganum and adult, but not in the parenchyma. The activities of alkaline phosphatase were stronger in the tegument than in the subtegumental musculature, and activities of acid phosphatase were stronger in the tegument of adults than those of sparganum. The 2 isozymes of alkaline and acid phosphatases were separated from s-sparganum (from snake) and r-sparganum (from experimentaly infected rats) respectively but 4 isozymes of Alp and 3 isoxymes of Acp were separated from adult worms by electrophoresis. In isogyme Alp, the 661)a was the common isozyme, but 130 kDa isozyme of Acp was the common isozyme in spargana and adult worms. By isoelectrofocusing, 4 isozymes (PI 7.9, 7.7, 6.5 and 6.3) and 2 isozymes (PI 7.9 and 7.7) of alkaline phosphatase were separated from adults and spargana respectively. In the stability against heat, activity of alkaline phosphatase was denatured perfectly after heating at 90℃ for 40 seconds. The optimum pH and temperature for activity of alkaline phosphatase were about pH 10 and 50℃, respectively. The maximum activity (unit) of alkaline phosphatase was 22.0 in s- sparganum,25.0 in r-sparganum and 215.0 in adult worms, so that the maximum activity was revealed higher in adults than spargana. As the result from above, we observed that alkaline and acid phosphatases were functioned mainly in the tegument and subtegumental musculature , and the isoxymes of phosphatase were activated differently according to habitat of the parasites. The spargana and adult worms carry out the pafasitism by adapting thenlselves to parasitic circumstance loth these emxymes.

• Parasites, Hosts and Diseases
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• v.28 no.1
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• pp.53-62
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• 1990

The growth and developmental pattern of H. continua was observed after experimental infection of their metacercariae to chicks. The recovery rate of worms from the chicks at 1 to 28 days post-infection(PI) was 12.8% in average. The rate remained fairly high for early 4 days of infection but decreased thereafter rapidly till 28 days PI. Most of the nukes, 91.9%, were recovered from the ileum of the chicks. In metacercariae, genital organs such as the ovary, testes, seminal vesicle, seminal receptacle and genital sucker were recognizable. At one day PI Mehlis'gland appeared, and at 2 days follicular vitellaria were observed. At 3 days PI, eggs were formed in the uterine tubule and increased in number as the worm grew old. The worms reached $2,990{\;}{\mu\textrm{m}}$ in length and $525{\;}{\mu\textrm{m}}$ in width at 28 days PI. Genital organs developed rapidly in early stages of infection but slowly thereafter to 28 days Pl, whereas non-genital organs developed steadily through the infection period. It was proved by this experiment that chicks should be a moderately suitable final host of H. continua.

• The Korean Journal of Food And Nutrition
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• v.24 no.4
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• pp.817-832
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• 2011

It is said that the reason Bulgarians enjoy longevity is that they have a lot of yogurt, whose $Lactobacillus$ controls intestinal poison-producing germs. In young individuals, the number of bifidobacteria exceeds 10 billion per 1 g of intestinal content, but this number decreases for older or senile individuals, who have a larger number of harmful microorganisms such as $Clostridium$. In addition, it is well known that artificially increasing intestinal bifidobacteria can help control harmful microorganisms and thus facilitate a healthier and longer life. The microorganisms used for artificial spawn are referred to as probiotic microorganisms, and in general, lactic acid bacteria(LAB) are used. Unlike antibiotics, which kill harmful microorganisms, probiotic microorganisms coexist with and control them, while improving the health of the individual, that is, they can improve and invigorate host cells. Because probiotic microorganisms and its products based on LAB are known to help prevent and treat constipation, diarrhea, intestinal inflammation, and blood cholesterol and generally improve health through the purification of intestines, its market has been continuously expanding. Korea imports approximately 90% of spawn and uses them. It is likely that they are not appropriate for Korean's physical condition. Thus, considering this problem into account, Entecbio, a biotech firm in Korea, has produced various products by using its proprietary microorganisms. In this paper, the effects, characteristics, and kinds of products from based on proprietary microorganisms, with its prospect for market, etc., are generally examined.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.1
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• pp.83-91
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• 2008

Dental caries which is one of the most common chronic disease complexly developed by the action of oral bacteria, diet, and host factor. Various prevention program enhance resistance of demineralization and reduce the acidogenecity of oral bacteria have been introduced, representative material is fluoride and chlorhexidine. The purpose of the study was to evaluate and compare effectiveness of fluoride varnish and chlorhexidine varnish in vivo. Bovine tooth specimens were implanted in the lower space maintainers and applied with fluoride varnish and chlorhexidine varnish. After seven days in oral environment, metal mesh was covered to make similar condition of plaque accumulation and induce caries. All specimens were analysed by EPMA to evaluate quantitative change of Ca, P and by polarized microscope to identify histological changes. The results were as follows : After initial artificial caries induction in the mouth, there were remarkable enamel caries lesion in the control group under polarized light microscopy. The highest amount of mineral decrease were showed in control group. No statistically significant mineral decrease were showed in fluoride varnish group, while chlorhexidine varnish group showed only significant decrease of P(P<0.05). In conclusion both fluoride varnish and chlorhexidine varnish seemed to be effective for protecting enamel surface from caries activity, although fluoride varnish has more anticariogenic effect than chlorhexidine varnish.

• KSBB Journal
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• v.20 no.2 s.91
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• pp.93-99
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• 2005

Polyunsaturated fatty acids, that is PUFAs, are important constituents of membranes particularly found in the retina and central nervous system. In microorganism-based PUFAs biosynthesis, the genus Thraustochytrids is well evaluated for their potential as a promising candidate in the practical production of PUFAs, such as AA and DHA. In this study, we attempted to optimize a method of total nucleic acid extraction from this microorganism as a preliminary experiment. Using the extracted nucleic acid and degenerated primers for direct PCR, we isolated a $\Delta5$ desaturase gene that contained 1320-nucleotide and encoded 439 amino acids. This gene exhibited an expected function, when expressed in P. pastoris in the presence of appropriate exogenous substrate, as an evidence for $\Delta5$ desaturase activity (conversion of DGLA to AA). These results and information could provide a basis for the construction of engineered strains suitable for the practical production of PUFAs.

• Korean Journal of Ichthyology
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• v.26 no.2
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• pp.83-88
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• 2014

An endemic Korean bitterling, Acheilognathus signifer, known as using freshwater mussels for its spawning activity, much prefers Lamprotula leai in Dalcheon stream (Goesan population) and Unio douglasiae sinuolatus in Gadaecheon (Danyang population) stream, Korea. The spawning pattern between two mussels and one bitterling was carried out in two populations from April to June, 2011 and 2013. L. leai in the Goesan population was bigger shell length and have more eggs, larvae or both with A. signifer than those of U. d. sinuolatus in the Danyang population. Also, A. signifer in the Goesan population appeared to have a longer ovipositor and lay ripen eggs more than those of A. signifer in the Danyang population. Glochidium, a larval stage, of some L. leai in the Goesan population was incubated in all the demibranch, whereas for all of U. d. sinuolatus in the Danyang population was found in the outer demibranch only. For L. leai in the Goesan population, the eggs, larvae or both of A. signifer were much more in the non-breeding mussels (giving no glochidium) than the breeding mussels having the glochidium. For U. d. sinuolatus in the Danyang population, in contrast, the non-breeding mussels have fewer eggs, larvae or both less than the breeding one.

• Weed & Turfgrass Science
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• v.4 no.2
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• pp.118-123
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• 2015

Metagenomics is a powerful tool to isolate novel biocatalyst and biomolecules directly from the environmental DNA libraries. Since the metagenomics approach bypasses cultivation of microorganisms, un-cultured microorganisms that are majority of exists can be the richest reservoir for natural products discovery. To discover novel herbicidal substances from soil metagenome, we established three easy, simple and effective high throughput screening methods such as cucumber cotyledon leaf disc assay, microalgae assay and seed germination assay. Employing the methods, we isolated two active single clones (9-G1 and 9-G12) expressing herbicidal activity which whitened leaf discs, inhibited growth of microalgae and inhibited root growth of germinated Arabidopsis seeds. Spraying butanol fraction of the isolated active clones' culture broth led to growth retardation or desiccation of Digitalia sanguinalis (L) Scop. in vivo. These results represent that the screening methods established in this study are useful to screen herbicidal substances from metagenome libraries. Further identifying molecular structure of the herbicidal active substances and analyzing gene clusters encoding synthesis systems for the active substances are in progress.

• Parasites, Hosts and Diseases
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• v.29 no.4
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• pp.325-338
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• 1991

The present study was undertaken to determine the endemicity of trematode infections in Yongyang County, Kyungpook Province, Korea. One hundred and seventy-seven out of 955 residents examined were found to be infected with one or more kinds of helminthes. The prevalence rate was 18.5%. Among them, 70 were found to be infected with Clenorchis sinensis, 74 with Meta-gonimus sp. and 2:l with both flukes. The eggs of Fasciolidae were demonstrated from two specimens. The prevalence rate of clonorchiasis in males was 12.6%, while that in females was 3.6% (p<0.05). The prevalence of metagonimiasis in males was 12.0% and was also significantly higher than 6.1% in females (p<0.05). The intensity of both infections was significantly heavier in males than in females. The prevalence of both nukes was higher in residents of oyer 30 years of age than in those below that age. No correlation was found between the intensity and the age group. Among eight species of the fresh-water fish collected at the Panbyon River, Zacco temmincki was found to be the most frequently and heavily infested with metacercariae of Metagonimus sp., and Gnathopogon asromaculatus alone was found to be infested with metacercariae of Clonorchis sinensis. The present results suggest that Yongyang area still remains endemic with Clonorchis sinensis and Metagonimus sp. infection.