• Korean Journal of Veterinary Research
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• v.27 no.1
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• pp.77-83
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• 1987

For the development of the specific pathogen free (SPF) or germ free laboratory animals, a parasitological approach was applied to the preliminarily selected laboratory albino mice (Mus musculus alba) in order to observe the ectoparasites on the hair of the host animal. The mites collected from the laboratory albino mice were identified as Myocoptes musculinus and classified into the Family Listrophoridae, Suborder Sarcoptiformes, Order Acarina. The overall infection rate of the mites was revealed as high as 73.2% (52 out of 71 heads) and the development process from the eggs to larvae was observed for the understanding of the basic ecological properties.

• Applied Microscopy
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• v.27 no.4
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• pp.347-355
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• 1997

These studies were performed to observe the morphological changes of synapses in the visual cortex of rat during early postnatal development. Specimens of the visual cortex were taken from rats (Sprague Dawley) at 1, 3, 7, 14 and 21 days of age, and prepared for silver impregnation and electron microscopy. The number of synapse and the length of postsynaptic thickening were increased progressively with age, especially 14 and 21 days. The number of dendritic spine was increased conspicuously on postnatal days 14-21. And asymmetic, curved and axo-spinous synapses were increased markedly at the same ages. The present findings suggest that spurt of synaptogenesis in the rat visual cortex occurs during early postnatal development, especially in second to 3rd week period and asymmetric and/or curved axo-spinous synapse is a matured form of synapse with advanced age.

• Mycobiology
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• v.48 no.4
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• pp.321-325
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• 2020

A Colletotrichum species was isolated from leaves of Cymbidium exhibiting symptoms of anthracnose. In this study, the isolates obtained were identified based on recent taxonomic approaches for the genus Colletotrichum. The identity of the causal pathogen was confirmed using morphological data and phylogenetic analysis of combined multi-gene dataset (internal transcribed spacer, glyceraldehyde 3-phosphate dehydrogenase, chitin synthase-1, actin, histone3, beta-tubulin, and calmodulin). Pathogenicity testing revealed that the isolates were pathogenic to Cymbidium. Based on these results, the fungal pathogen occurring on Cymbidium orchids was identified as Colletotrichum cymbidiicola, which is a newly recorded species in Korea.

• Mycobiology
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• v.48 no.5
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• pp.418-422
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• 2020

In 2016, a cercosporoid fungus was found from leaf spot symptoms on melon in Korea. The fungus isolated from the plant was identified based on morphological characteristics and sequence analyses of five genes (ITS rDNA, translation elongation factor 1-α, actin, calmodulin, and histone H3). The fungal isolate was found to be pathogenic to melon. The results confirm that the fungus associated with leaf spot on melon was Cercospora cf. flagellaris. This is the first report of Cercospora cf. flagellaris causing Cercospora leaf spot on melon in Korea.

• The Korean Journal of Mycology
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• v.49 no.3
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• pp.399-403
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• 2021

Stem blight symptoms were observed in greenhouse-grown bottle gourds (Lagenaria siceraria) in Wanju, Korea. Infected plants showed leaf chlorosis and wilting; the plants eventually died with the infected leaves remaining attached, and black sclerotia formed on the diseased stem. Based on the morphological characteristics and pathogenicity results and sequence analyses of the internal transcribed spacer, translation elongation factor 1-α, β-tubulin, and calmodulin regions, the isolated fungus was Macrophomina phaseolina. This is the first report of charcoal rot in Lagenaria siceraria caused by Macrophomina phaseolina in Korea.

• Mycobiology
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• v.42 no.2
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• pp.203-205
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• 2014

In 2010, symptoms of leaf and stem rot were observed on potted plants (Peperomia quadrangularis) in a greenhouse in Yongin, Korea. The causative pathogen was identified as Myrothecium roridum based on morphological data, internal transcribed spacer sequence analysis, and pathogenicity test. To our knowledge, this is the first report of M. roridum causing leaf and stem rot disease on P. quadrangularis in Korea and elsewhere worldwide.

• Fisheries and Aquatic Sciences
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• v.21 no.2
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• pp.4.1-4.5
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• 2018

Insulin-like growth factors (IGFs), along with IGF-binding protein and IGF receptor, are well-known regulators in the growth and survival of vertebrates. In this study, we investigated the involvement of IGFs and protein variation during embryonic development of the olive flounder (Paralichthys olivaceus). Morphological stages were divided into six main developments as blastula, gastrula, cephalization, cranial regionalization, tail lift, and hatch. During embryonic development, protein variation was investigated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electrospray ionization quadrupole time-of-flight mass spectrometry/mass spectrometry. In addition, the mechanism of signaling of IGF-I receptor was examined using immuno-blot analysis. We found marked changes in protein expression at four stages of embryonic development and identified proteins as belonging to the vitellogenin 2 family. As development progresses, expression of IGF-II, phosphotyrosine, and phospho-Akt increased, while expression of growth factor receptor-bound protein 2 (GRB2) and one of guanine-nucleotide-binding proteins (Ras) decreased. These results provide basic information on the IGF system in the embryonic development of the olive flounder.

• Mycobiology
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• v.51 no.4
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• pp.264-272
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• 2023

Onion (Allium cepa L.) is an economically important vegetable crop worldwide. However, various fungal diseases, including Fusarium basal rot (FBR), neck rot, and white rot, reduce onion production or bulb storage life. FBR caused by Fusarium species is among the most destructive onion diseases. In this study, we identified Fusarium species associated with FBR in Jeolla and Gyeongsang Provinces in South Korea and evaluated fungicides against the pathogens. Our morphological and molecular analyses showed that FBR in onions is associated with Fusarium commune, Fusarium oxysporum, and Fusarium proliferatum. We selected seven fungicides (fludioxonil, hexaconazole, mandestrobin, penthiopyrad, prochloraz-manganese, pydiflumetofen, and tebuconazole) and evaluated their inhibitory effects on mycelial growth of the pathogens at three different concentrations (0.01, 0.1, and 1 mg/mL). We found that prochloraz-manganese was highly effective, inhibiting 100% of the mycelial growth of the pathogens at all concentrations, followed by tebuconazole. Fludioxonil showed < 50% inhibition at 1 mg/mL for the tested isolates.

• Toxicological Research
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• v.13 no.1_2
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• pp.39-48
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• 1997

Cyclophosphamide(25, 50 or 100 mg/kg), orally administered to male Sprague-Dawley rats, caused a time- and dose-dependent thymic atrophy. In the light microscopic examination of the atrophic thymus, thymocytes with condensed or fragmented nucleus were multifocally observed in the cortical region, started to increase 8 hr after CPA treatment and reached to the maximal level at 16 hr, although such cells were not seen after 48 hr when the severe depletion of thymocytes were marked. In agarose gel electrophoresis to analyze the DNA changes, DNA extracted from atrophic thymus showed a oligonucleosomal laddering at the corresponding time to morphological changes. In an additional supportive experiment, thymocytes showing morphological changes, nuclear condensation or apoptotic body, exhibited a positive reaction to immunoperoxidase staining using in situ apoptosis detection kit. Separately, agarose gel electrophoresis of DNA from bone .marrow cells was performed to investigate the involvement of bone marrow cells in the process of thymocyte apoptosis. Although DNA laddering was slightly increased 2 and 4 hr after treatment, no clear correlation was inferred. Taken togather, it is concluded that thymocytes showing morphological changes in thymic atrophy induced by cyclophosphamide administration represent an apoptosis having biochemical nature of programmed cell death.

• Journal of Forest and Environmental Science
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• v.28 no.4
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• pp.199-204
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• 2012

This study was conducted to estimate climax index by eco-morphology for major 36 tree and sub-tree species in natural deciduous forests so as to interpret seral position of each species in the forest community. Fourteen eco-morphological characters which were considered to be associated with successional gradient in the forest were selected for the study. Four levels per character for each species were given on a standardized scale of increasing climax, and the index was computed by the proportion of the sum of total scores, expressed by percent values. With calculated mean value of 54.8 for all indices, Carpinus cordata had the highest index value of 90.5, and Populus davidiana recorded the lowest of 13.2. The most climax group, greater than 70 of the index, contained only 8 species, intermediate group, between 41 to 70 of the index, had 23 species, and the most pioneer group, less than 40 of the index comprised 5 species. The result has noticed that the large number of species would take advantage of most diverse resource and niche in the intermediate stage of the sere in the forest. By cluster analysis all 36 species were subjected to be classified into several species groups which had common similar eco-morphological characteristics. The indices were additionally plotted on the two dimensional graph to recognize the positions related to the light absorption factor and reproduction factor. The climax index of tree and sub-tree species developed by this study could be applied to understand the present status of successional stage on the basis of species composition by the method of summing up the indices. And comparison of forest successional stage among various forest communities could be done by summing up the climax indices of composed species in each community. However, this kind of applied methodology should be limited to the forest of similar species composition and site condition.