• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.11-11
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• 2014

Fungal pathogens have huge impact on health and economic wellbeing of human by causing life-threatening mycoses in immune-compromised patients or by destroying crop plants. A key determinant of fungal pathogenesis is their ability to undergo developmental change in response to host or environmental factors. Genetic pathways that regulate such morphological transitions and adaptation are therefore extensively studied during the last few decades. Given that epigenetic as well as genetic components play pivotal roles in development of plants and mammals, contribution of microbial epigenetic counterparts to this morphogenetic process is intriguing yet nearly unappreciated question to date. To bridge this gap in our knowledge, we set out to investigate histone modifications among epigenetic mechanisms that possibly regulate fungal adaptation and processes involved in pathogenesis of a model plant pathogenic fungus, Magnaporthe oryzae. M. oryzae is a causal agent of rice blast disease, which destroys 10 to 30% of the rice crop annually. Since the rice is the staple food for more than half of human population, the disease is a major threat to global food security. In addition to the socioeconomic impact of the disease it causes, the fungus is genetically tractable and can undergo well-defined morphological transitions including asexual spore production and appressorium (a specialized infection structure) formation in vitro, making it a model to study fungal development and pathogenicity. For functional and comparative analysis of histone modifications, a web-based database (dbHiMo) was constructed to archive and analyze histone modifying enzymes from eukaryotic species whose genome sequences are available. Histone modifying enzymes were identified applying a search pipeline built upon profile hidden Markov model (HMM) to proteomes. The database incorporates 22,169 histone-modifying enzymes identified from 342 species including 214 fungal, 33 plants, and 77 metazoan species. The dbHiMo provides users with web-based personalized data browsing and analysis tools, supporting comparative and evolutionary genomics. Based on the database entries, functional analysis of genes encoding histone acetyltransferases and histone demethylases is under way. Here I provide examples of such analyses that show how histone acetylation and methylation is implicated in regulating important aspects of fungal pathogenesis. Current analysis of histone modifying enzymes will be followed by ChIP-Seq and RNA-seq experiments to pinpoint the genes that are controlled by particular histone modifications. We anticipate that our work will provide not only the significant advances in our understanding of epigenetic mechanisms operating in microbial eukaryotes but also basis to expand our perspective on regulation of development in fungal pathogens.

• Korean Journal of Ichthyology
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• v.9 no.1
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• pp.15-21
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• 1997

The influence of delayed(1, 2, 3, 4 days) feeding and starvation on morphological change and survival rate of the spotted sea bass larvae was examined at the KORDI laboratories which located at Poryong Power Plant, Poryong-gun, Chungchongnam-do in November, 1996. 1. The larvae of spotted sea bass began to feed on rotifers at 5 days after hatching. In case of non-feeding, all of the larvae died at 9 days after hatching. The larvae which fed 1 day after the normal first feeding schedule(1 day delayed) grew normally and 2 days delayed groups showed 5.3% in survival rate at 9 days after hatching. In case of non-feeding and 3 or 4 days delayed groups, all of the larvae died between 9 and 10 days after hatching. 2. In case of non-feeding, total length of the larvae decreased gradually. 3. The percente ratio of gut height and mytome height to standard length in starved larvae has declined most rapidly compare to other demensions during the non-feeding period. The percente ratio of gut height to mytome height had also difference between unfed and fed larvae. At 9 days after hatching, the ratio of that between fed and unfed larvae were 84.5 % and 52.4 %, respectively. 4. The morphology of starving larvae were characterized as sharpened jaw, projected edge of lower part of clavicle and bending trunk with slenger gut.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.294-294
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• 2017

Rice (Oryza sativa L.) is one of the main agricultural crops in Asian countries, including Korea, and is considered as the most important staple food in the world. Rice is also processed into flour, which is consumed through various foods such as cake, noodle, bread, and confectionary. Rice flour quality is highly dependent on variety and milling conditions. Producing rice flour with fine particles is more difficult than wheat flour because of its grain hardness. The Korean rice varieties representing different amylose contents were selected for this study. The relationship between the morphological and starch characteristics of rice kernels and the appropriate varieties for producing good-quality, dry-milled rice flour were examined. The hardness of the rice kernels was determined by measuring the pressure at the grain breakage point. The damaged starch content of the rice flour was determined using a Megazyme starch damage assay kit. The particle-size distribution of the rice flour was measured as the volume-base distribution using a laser-diffraction particle size analyzer. The mean particle-size distribution of the dry-milled flour obtained was between $65.3{\sim}105.1{\mu}m$ among the rice varieties. The opaque, non-glutinous, Seolgaeng rice demonstrated a narrow peak at the fine size, whereas the entire particle-distribution range for other varieties was wide. Seolgaeng exhibited significantly lower damaged starch content of dry-milled flour than the other varieties (p < 0.05). Seolgaeng showed lowest in energy consumption on rice flour production with 200 mesh particle size. Accordingly, it is possible to produce dry-milled rice flour which is similar to wheat flour that would considerably reduce milling costs.

• Development and Reproduction
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• v.18 no.1
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• pp.13-23
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• 2014

This study is conducted to monitor the morphological developmental features of the egg development, larvae and juvenile of Epinephelus septemfasciatus, the fertilized eggs were gotton using artificial insemination. Matured parents are collected from marine caged fish farms in Geomun-ri, Samsan-myeon, Yeosu-si, Jeollanamdo Korea in June 2012. The fertilized eggs were pelagic eggs containing one oil globule, and measured 0.81~0.89 mm ($0.85{\pm}0.04mm$, n=50) in diameter. In regard to rearing environment, the water temperature is $21.0{\sim}23.0^{\circ}C$ and the salinity is 32.0~33.2‰. Hatching was observed from 48 hours after fertilization, the mouth and anus of prelarvae was not opened but had egg yolk at newly hatched. 4 days after hatching, the mouth and anus of postlarvae was opened and began to eat Rotifer and was measured 2.40~2.49 mm ($2.45{\pm}0.03mm$ n=10) in total length. 12 days after hatching, postlarvae was measured 3.77~4.67 mm ($4.27{\pm}0.33mm$) in total length, its the second pole tide of dorsal fin and the first pole tide of pelvic fin was extended longitudinally. 71 days after hatching, juvenile was measured 40.5~45.4 mm ($42.6{\pm}2.04mm$) in total length. Seven bands were observed in body, and pole tides of dorsal and pelvic fins were shortened.

• Environmental Mutagens and Carcinogens
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• v.25 no.1
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• pp.25-31
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• 2005

The objective was to use MR imaging to provide a template of posterior fossa development during the late stages in the chick embryos. The MR findings were then correlated with histological data. Fourteen normal formalin-fixed embryonic specimens with a gestational age of 14 to 20 days were examined with 1.5 Tesla unit MRl using a conventional clinical magnet and pulse sequences. The MR findings were correlated with the whole-mount histological specimens. Resolution of the morphological features of posterior fossa development in embryos greater than 14 days gestational age was possible. Development of cerebellum, brain stem, 4th ventricle and bony posterior fossa was documented. In the 14-day-old embryos, a premordial cerebellum was visualized in the enlarged bony posterior fossa, and it covered the the roof of the primitive fourth ventricle. The bony posterior fossa grows at the same rate along the supratentorial skull. The supratentorial skull and the rostral part of the brain grows at the same rate. The cerebellum begins to grow later than the rostral part of the brain. In the 19- to 20-day-old embryos, MRl revealed the rapid development of the cerebellar hemispheres, along with an increase in volume manifested by the more typical mushroom-shaped configuration observed in the newly hatched. At this stage, the cerebellum almost completely filled the posterior fossa and covered the entire fourth ventricle. The brain stem grew steadily, but the volume change was too subtle to evaluate. Features of cerebellar histogeneis were beyond the resolution of MRl. However, there were lots of artifacts in the features of the bony posterior fossa. An MR template of normal posterior fossa development would be useful to avoid confusion of normal development with abnormal development and to identify the expected developmental features when provided the estimated gestational age of a embryo.

• The Plant Pathology Journal
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• v.40 no.1
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• pp.16-29
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• 2024

The Colletotrichum gloeosporioides species complex includes many phytopathogenic species, causing anthracnose disease on a wide range of host plants and appearing to be globally distributed. Seventy-one Colletotrichum isolates in the complex from different plants and geographic regions in Korea were preserved in the Korean Agricultural Culture Collection (KACC). Most of them had been identified based on hosts and morphological features, this could lead to inaccurate species names. Therefore, the KACC isolates were re-identified using DNA sequence analyses of six loci, comprising internal transcribed spacer, gapdh, chs-1, his3, act, and tub2 in this study. Based on the combined phylogenetic analysis, KACC strains were assigned to 12 known species and three new species candidates. The detected species are C. siamense (n = 20), C. fructicola (n = 19), C. gloeosporioides (n = 9), C. aenigma (n = 5), C. camelliae (n = 3), C. temperatum (n = 3), C. musae (n = 2), C. theobromicola (n = 2), C. viniferum (n = 2), C. alatae (n = 1), C. jiangxiense (n = 1), and C. yulongense (n = 1). Of these, C. jiangxiense, C. temperatum, C. theobromicola and C. yulongense are unrecorded species in Korea. Host plant comparisons showed that 27 fungus-host associations are newly reported in the country. However, plant-fungus interactions need to be investigated by pathogenicity tests.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.9
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• pp.1286-1290
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• 2004

This study was carried out to screen yeasts effective in reducing odor from pig feces. Three isolates from soil and compost sources were selected to treat pig feces. On the basis of morphological and biochemical characteristics, one isolate from compost was Candida rugosa, and two isolates from soil were Candida rugosa and Candida maris. These isolates showed deodorizing activity by reducing the concentration of ${NH}_3$ and R-${NH}_2$. Volatile fatty acids (VFA) are the specific malodorous compounds of pig feces, and the Candida maris from soil showed a 100% reduction of butyric, iso-butyric, and iso-valeric acid in 10% pig slurry medium. However, the Candida rugosa from compost showed a 100% reduction of butyric and iso-butyric acid while that from soil showed a 100% reduction of propionic, butyric acid and iso-valeric acid in the medium. Also, these yeasts were effective in reducing $NH_{4}-N$, soluble-N, and biological oxygen demand (BOD).

• Applied Microscopy
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• v.19 no.1
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• pp.70-88
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• 1989

The storage sac of U. unicinctus can be divided into two parts morphologically as well as functionally ; one is proximal and the other distal storage sac. It is because of the seasonal morphological change of the storage sac caused by sperm accumulation in the storage sac. The proximal storage sac contains the mature sperm with the dumbbell-shaped acrosome and well developed one or two mitochondria in the middle piece, whilst the sperm of hemispherical acrosome associate closely with an accessory cell in the distal storage sac. This means that the sperm do not perform the synchronous development in a storage sac, which is not the case of sperm development in the coelomic cytophorus. In addition, the basal membrane of the distal storage sac is different from that of the proximal storage sac in term of tissue formation. Connective tissues, acces-sory cells and small lumen develop on the basal membrane of the distal sto-rage sac, which is well contrasted with the thin basal membrane of the proximal storage sac. The function of the storage sac is discussed in rela-tion of the sperm development and the seasonal change.

• The Plant Pathology Journal
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• v.17 no.6
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• pp.357-360
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• 2001

Gray mold was observed on leaves of castor bean grown in Woniu and Okcheon in Korea in October 2000. Symptoms developed in the form of spot and blight with sporulation of the causal fungi at the marginal or central parts of the leaves. A total of 25 isolates were obtained from the infected leaves of castor bean. Out of the 25 isolates, 5 isolates which originated from Woniu were identified as Botrytis cinerea, while 20 isolates from Okcheon were identified as Amphobotrys ricini based on morphological and cultural characteristics. Two isolates each of B. cinerea and A. ricini were tested for their pathogenicity to castor bean plants. Gray mold symptoms similar to those observed in the fields were induced on leaves of castor bean by artificial inoculation. This is the first report of gray mold in castor bean caused by B. cinerea and A. ricini in Korea.

• Journal of fish pathology
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• v.12 no.2
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• pp.101-105
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• 1999

In a survey of net-caged yellowtail Seriola quinqueradiata in the southern parts of Korean Peninsula, we found infestations of ciliate in the gills of the moribund fish during the abnormally elevated temperature. The ciliate was very similar to genus Colpoda Muller, 1773 on morphological and reproductive characteristics. Histopathological changes revealed that the ciliate invaded gills only, causing extensive destruction of the gill filaments including lamella without any clinical signs found in the other organs and tissues. This is the first record of the parasitic ciliate in cultured yellowtail.