• Mycobiology
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• v.47 no.3
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• pp.261-272
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• 2019

Oomycetes are widely distributed in various environments, including desert and polar regions. Depending upon different habits and hosts, they have evolved with both saprophytic and pathogenic nutritional modes. Freshwater ecosystem is one of the most important habitats for members of oomycetes. Most studies on oomycete diversity, however, have been biased mostly towards terrestrial phytopathogenic species, rather than aquatic species, although their roles as saprophytes and parasites are essential for freshwater ecosystems. In this study, we isolated oomycete strains from soil sediment, algae, and decaying plant debris in freshwater streams of Korea. The strains were identified based on cultural and morphological characteristics, as well as molecular phylogenetic analyses of ITS rDNA, cox1, and cox2 mtDNA sequences. As a result, we discovered eight oomycete species previously unknown in Korea, namely Phytopythium chamaehyphon, Phytopythium litorale, Phytopythium vexans, Pythium diclinum, Pythium heterothallicum, Pythium inflatum, Pythium intermedium, and Pythium oopapillum. Diversity and ecology of freshwater oomycetes in Korea are poorly understood. This study could contribute to understand their distribution and ecological function in freshwater ecosystem.

• Mycobiology
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• v.47 no.3
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• pp.280-291
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• 2019

To explore species diversity of Hypocreaceae, collections from Guangdong, Hubei, and Tibet of China were examined and two new species and a new Chinese record were discovered. Morphological characteristics and DNA sequence analyses of the ITS, LSU, $EF-1{\alpha}$, and RPB2 regions support their placements in Hypocreaceae and the establishments of the new species. Hypomyces hubeiensis sp. nov. is characterized by occurrence on fruitbody of Agaricus sp., concentric rings formed on MEA medium, verticillium-like conidiophores, subulate phialides, rod-shaped to narrowly ellipsoidal conidia, and absence of chlamydospores. Trichoderma subiculoides sp. nov. is distinguished by effuse to confluent rudimentary stromata lacking of a well-developed flank and not changing color in KOH, subcylindrical asci containing eight ascospores that disarticulate into 16 dimorphic part-ascospores, verticillium-like conidiophores, subcylindrical phialides, and subellipsoidal to rod-shaped conidia. Morphological distinctions between the new species and their close relatives are discussed. Hypomyces orthosporus is found for the first time from China.

• The Korean Journal of Mycology
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• v.47 no.3
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• pp.209-218
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• 2019

During a survey of fungal diversity in Korea, two fungal strains, KNU17-1 and KNU17-199, were isolated from paddy field soil in Yangpyeong and Sancheong, respectively, in Korea. These fungal isolates were analyzed based on their morphological characteristics and the molecular phylogenetic analysis of the internal transcribed spacer (ITS) rDNA sequences. On the basis of their morphology and phylogeny, KNU17-1 and KNU17-199 isolates were identified as Albifimbria verrucaria and Deconica coprophila, respectively. To the best of our knowledge, A. verrucaria and D. coprophila have not yet been reported in Korea. Thus, this is the first report of these species in Korea.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.8
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• pp.366-374
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• 2014

Experimental mass transfer data, which were obtained for the $CO_2$-water slug flows in vertical tubes with 2, 5, and 8mm diameters, were analyzed in comparison with the penetration theory. It was found that a penetration model with molecular diffusion coefficient cannot predict the experimental data accurately. An effective diffusion coefficient, which considers enhancement effect of interfacial waves, was suggested to improve prediction. Another empirical factor was also suggested to consider the effect of non-uniform interface velocity. A modified penetration model was found to be capable of predicting the experimental data reasonably well.

• Archives of Pharmacal Research
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• v.16 no.2
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• pp.140-146
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• 1993

A colostral protein that augments natural killer (NK) cell activity was isolated from bovine colostrum. This protein, designated matemal immunity enhancing factor (MIEF), increased NK cell-mediated cytotxicity against human tumor targets wheb added to cultures of resting peripheral blood lymphocytes. The NK cell stimulatory activity of the MIEF was demonstrated at the concentrations as low as 0.1-0.01 $\mu$g/ml. Purified MIEF showed an apparent molecular weight of 22,000 in SDS-polyacrylamide gel electrophoresis. The unusual biochemical characteristics of the MIEF distinguish it from other cytokines. The MIEF was soluble at a cold tgemperature, and precipitated by raising the temperature. This themal precipitability was reversible, and dependent on the concentration, pH and ionic strength. Maximal precipitation was observed at neutral pH, and higher ionic strength.

• Biomedical Science Letters
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• v.27 no.3
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• pp.111-120
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• 2021

Asbestos products had been widely used until 2007 in Korea since the 1930s. A total ban on their production and applications has been imposed because of the toxic effect of asbestos fibers on the human health. The inhaled asbestos fibers increase reactive oxygen species and inflammatory reactions in the respiratory airway including the alveolar sac, resulting in DNA damages and secretion of several inflammatory cytokines or chemokines. These paracrine communications promote the proliferation of fibroblasts and the synthesis of collagen fibers, thereby depositing them into the extracellular matrix at the interstitial space of alveoli. The fibrotic tissue hindered the gas exchange in the alveolus. This reviews describes not only the cytotoxic effects of asbestos fibers with different physical or chemical characteristics but also the interaction of cells that make up the respiratory airway to understand the molecular or cellular mechanisms of asbestos fiber-induced toxicity. In addition, we propose a pulmonary toxicity research technique based on the mini-lung that can mimic human respiratory system as an alternative to overcome the limitations of the conventional risk assessment of asbestos fibers.

• Korean Journal of Environmental Biology
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• v.39 no.3
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• pp.399-405
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• 2021

Until now, five species (Meghimatium bilineatum, M. fruhstorferi, Limax flavus, L. marginatus, Deroceras reticulatum) in three genera of families Philomycidae and Limacidae have been reported in Korea. Philomycidae is a family of air-breathing land snails. Meghimatium hongdoensis sp. nov. is described based on its middle size (60-80 mm in body length), its body coloration (dark-red yellow), no dorsal with streaks, its genitalia, and 16rDNA sequence analysis. Specimens of this new species were collected from Hongdo island, Sinan-gun, Jeollanam-do, Korea. This species is only known from the type locality at Hongdo to date. It could be found in high-humidity sites. Meghimatium uniforme (Laidlaw 1937) was the first one reported in Korea. It was also collected from Gageodo island, Sinan-gun, Jeollanam-do, Korea. In this study, morphological characteristics including their radula and genital structures of these two species were described. Preliminary results of mitochondrial 16S rDNA sequencing and phylogenetic analyses indicated that these species belonged to the Korean clade.

• Ocean and Polar Research
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• v.43 no.4
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• pp.353-363
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• 2021

Fluorescent dissolved organic matter (FDOM) is referred to organic matter which absorbs efficiently solar radiation energy and fluorescence in the water column. The component and molecular structure of marine organic matter can be changed depending on the various substances and origins of organic matter, and then the organic matter has unique fluorescent properties. As the cutting-edge analytical techniques of optical measurement continuously developing from last few decades, a study on FDOM has been applied as a biogeochemical tracer to quantify the organic matter concentration and to investigate the behaviors and origins of organic matter. Especially, the marine environment around the Korean Peninsula is an ideal research area to study FDOM because of various oceanographic characteristics and the origins of organic matter. This study describes the general properties of FDOM and introduces the cycling and behaviors of marine organic matter based on the domestic research studies.

• The Korean Journal of Mycology
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• v.49 no.4
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• pp.555-560
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• 2021

During disease surveys conducted from 2019 to 2021 in Korea, leaf spot symptoms in rhubarb (Rheum rhabarbarum) plants were frequently observed in plants growing in fields located in Cheolwon, Taebaek, and Inje in Gangwon Province. The incidence of diseased leaves of the plants in the fields ranged from 2% to 80%. Nine single-spore isolates of Phoma sp. were obtained from lesions of the diseased leaves; all of them were identified as Didymella rhei based on their cultural, morphological, and molecular characteristics. Three isolates of D. rhei were tested for pathogenicity on rhubarb leaves using artificial inoculation. All the tested isolates caused leaf spot symptoms in the inoculated plants; the symptoms were similar to those observed in plants from the fields investigated. This is the first report of D. rhei causing leaf spot in rhubarb in Korea.

• The Korean Journal of Mycology
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• v.49 no.2
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• pp.139-153
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• 2021

The Inocybaceae is a family of ectomycorrhizal fungi belonging to the Agaricales order. Most species in this family produce secondary metabolites, such as muscarine, psilocybin, and other compounds. In the present study, we conducted taxonomic studies on the Inocybaceae based on morphological and molecular phylogenetic analyses for the first time in Korea. As a result, seven species of Inocybaceae were newly recorded: Inocybe caroticolor, I. fuscidula, I. grammatoides, I. latibulosa, I. stellata, Inosperma shawarense, and Mallocybe malenconii. Among them, the genera Inosperma and Mallocybe were described for the first time in Korea. Relevant morphological characteristics, phylogenetic trees, and photographs are provided.