• Mycobiology
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• v.51 no.2
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• pp.79-86
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• 2023

In this study, fungal strains designated as KNUF-22-14A and KNUF-22-15A were isolated from soil samples in Korea. These two strains were identified based on cultural and morphological characteristics as well as phylogenetic analyses and were found to be morphologically and phylogenetically identical. Upon their morphological comparison with closely related species, such as Tolypocladium album, T. amazonense, T. endophyticum, T. pustulatum, and T. tropicale, a difference in the size of short phialides [0.6-2.4(-9.3)×0.8-1.4 ㎛] was observed. Meanwhile, these strains had larger conidia (1.2-3.0×1.2-3.0 ㎛) than T. album, T. amazonense, T. endophyticum, and T. tropicale and smaller conidia than T. pustulatum. Phylogenetic analyses using a multi-locus datasets based on ITS, LSU, and SSU showed that KNUF-22-14A and KNUF-22-15A formed a distinct cluster from previously identified Tolypocladium species. Thus, these fungal strains isolated from soil in Korea are proposed as a novel species according to their characteristics and are named Tolypocladium globosum sp. nov.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.28.2-28.2
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• 2021

We investigate the impact of ram pressure stripping due to the intracluster medium (ICM) on star-forming disk galaxies with a multiphase interstellar medium maintained by strong stellar feedback. We carry out radiation-hydrodynamic simulations of an isolated disk galaxy embedded in a 1011 M⦿ dark matter halo with various ICM winds mimicking the cluster outskirts (moderate) and the central environment (strong). We find that both star formation quenching and triggering occur in ram pressure-stripped galaxies, depending on the strength of the winds. HI and H2 in the outer galactic disk are significantly stripped in the presence of moderate winds, whereas turbulent pressure provides support against ram pressure in the central region, where star formation is active. Moderate ICM winds facilitate gas collapse, increasing the total star formation rates by ~40% when the wind is oriented face-on or by ~80% when it is edge-on. In contrast, strong winds rapidly blow away neutral and molecular hydrogen gas from the galaxy, suppressing star formation by a factor of 2 within ~200 Myr. Dense gas clumps with nH≳10 M⦿ pc-2 are easily identified in extraplanar regions, but no significant young stellar populations are found in such clumps. In our attempts to enhance radiative cooling by adopting a colder ICM of T=106K only a few additional stars are formed in the tail region, even if the amount of newly cooled gas increases by an order of magnitude.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.65.3-66
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• 2020

We use the IllustrisTNG cosmological hydrodynamical simulation to study the evolution of star formation rate (SFR)-density relation over cosmic time. We construct several samples of galaxies at different redshifts from z=2.0 to z=0.0, which have the same comoving number density. The SFR of galaxies decreases with local density at z=0.0, but its dependence on local density becomes weaker with redshift. At z≳1.0, the SFR of galaxies increases with local density (reversal of the SFR-density relation), and its dependence becomes stronger with redshift. This change of SFR-density relation with redshift still remains even when fixing the stellar masses of galaxies. The dependence of SFR on the distance to a galaxy cluster also shows a change with redshift in a way similar to the case based on local density, but the reversal happens at a higher redshift, z~1.5, in clusters. On the other hand, the molecular gas fraction always decreases with local density regardless of redshift at z=0.0-2.0 even though the dependence becomes weaker when we fix the stellar mass. Our study demonstrates that the observed reversal of the SFR-density relation at z≳1.0 can be successfully reproduced in cosmological simulations. Our results are consistent with the idea that massive, star-forming galaxies are strongly clustered at high redshifts, forming larger structures. These galaxies then consume their gas faster than those in low-density regions through frequent interactions with other galaxies, ending up being quiescent in the local universe.

• Journal of Species Research
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• v.13 no.1
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• pp.10-31
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• 2024

In this study, 11 strains of epilithic cyanobacteria belonging to six unrecorded species in Korea were isolated from gravel submerged in freshwater of seven collection sites in Korea. The morphological characteristics of the six species isolated in this study were consistent with the type strain of each species, and the similarity of the 16S rRNA gene sequences with the type strain of each species were 98.8-100%. In the phylogenetic tree using the 16S rRNA gene sequences, the 11 strains of these six species formed the same cluster as the strains of each species. The habitat of each previously reported species is mainly the soil surface, but all Korean strains appeared from the gravel submerged in freshwater. As a result of the morphological, ecological, and molecular analyses, these six species of cyanobacteria were identified as Geminocystis papuanica, Allocoleopsis franciscana, Ancylothrix terrestris, Klisinema persicum, Scytolyngbya timoleontis, and Shackletoniella antarctica, which were added as newly recorded species in Korea.

• IMMUNE NETWORK
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• v.20 no.3
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• pp.21.1-21.10
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• 2020

TLRs are pattern recognition receptors (PRRs) whose cytoplasmic signalling domain is similar to that of IL-1. The extracellular domain of TLRs serve as the binding site of pathogen associated molecular patterns. TLRs are found on both plasma and endosomal membranes and they mainly exert their function by activating genes which lead to production of inflammatory factors. The latest TLR to be discovered, TLR10 is a unique TLR which exhibit anti-inflammatory properties. TLR10 is found on the plasma membrane with other TLRs namely TLR1, TLR2, TLR4, TLR5 and TLR6. Studies have revealed that TLR10 is found on the same gene cluster with TLR1 and TLR6 and is also a coreceptor of TLR2. Up to date, TLR10 is the only TLR which exhibit anti-inflammatory property. Previously, TLR10 was thought to be an "orphan receptor" but much recent studies have identified ligands for TLR10. Currently there is no review article on TLR10 that has been published. In this narrative review, we are going to give an account of TLR10, its functions mainly as an anti-inflammatory PRR and its possible applications as a target in therapeutics.

• The Korean Journal of Mycology
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• v.27 no.1 s.88
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• pp.39-43
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• 1999

The internal transcribed spacer II regions (ITS II) of the ribosomal DNA gene repeat from Ganoderma spp. were amplified using polymerase chain reaction (PCR) and sequenced. Sequences from 9 species including Ganoderma lucidum, G. tsugae, G. pfeifferi, G. resinaceum, G. australe-applanatum, G. oregonense, G. neo-japonicum, G. applanatum and Inonotus xeranticus as an out-group were compared. The spacer regions of them were $247{\sim}257$ nucleotides in length and contained partial sequences of 5.8S and 25S gene. The reciprocal homologies of each ITS II sequence of the species were in the range of $70{\sim}100%$ except outgroup species, I. xeranticus. According to the analysis of ITS II sequences, Ganoderma spp. constructed 5 clusters. Ganoderma lucidum isolates were to be divided into two groups. One group was consisted of isolates from South Korea. The other group comprised isolates from UK. G. lucidum isolates belonging to the group I were closely related with G. tsugae. These results suggested that G. lucidum from Korea should be G. tsugae, otherwise G. tsugae was to be synonym of G. lucidum.

• Korean Journal of Plant Resources
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• v.17 no.2
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• pp.82-93
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• 2004

Phylogenetic relationships among species in Araliaceae were analyzed using PCR-RAPD and sequence of ITS region of nuclear ribosomal DNA based on samples collected in Korea. RAPD analysis showed various polymorphic bands which were able to differentiate species and genus, and specific bands showing variations among individuals within species. Cluster analysis using gel images revealed high molecular variability within species of Aralia eleta. No significant variation was found among cultivated species of Panax ginseng, but they showed high genetic differences with wild type of the species. In ITS analysis, specific sequences for each genus and species were observed and these were allowed to differentiate species and genus. Phylogenetic analysis using ITS sequences showed that Acanthopanax and Kalopanax had a close relationship, and Aralia and Panax are monophyletic, but genus Hedera is different species from other species in family Araliaceae in this study. The results showing close relationship between genera Aralia and Panax were also observed in RAPD analysis. Contrary to the results of RAPD analysis of Panax ginseng, sequence analysis of ITS showed no significant difference between wild mountain ginseng and cultivated species of P. ginseng. Also, both RAPD and ITS analysis of P. ginseng showed no significant genetic variability among cultivation sites. Results indicate that P. ginseng cultivating in Korea is monophyletic. The molecular analysis used in this study agreed on classification using morphological feature. These results suggest that molecular techniques used in this study could be useful for phylogenetic analysis of Araliaceae.

• Journal of Life Science
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• v.27 no.4
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• pp.408-416
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• 2017

This research aimed to identify the diversity and the distribution of invasive alien plant species in the metropolitan city of Busan, South Korea. According to our results, we discovered 10 species of invasive alien plants distributed in Busan, demonstrating that this urban area has a high domestic plant diversity. A cluster analysis identified that the dominant communities of Aster pilosus, Lactuca serriola, Ambrosia artemisiifolia, Rumex acetosella and Solanum carolinense were highly similar in species composition. Different species of invasive alien plants tended to occur together in dominant communities, indicating their preference for shared habitats. The most extensively distributed species in Busan were Lactuca serriola (16 districts), followed by Ambrosia artemisiifolia (11 districts), Aster pilosus (11 districts) and Rumex acetosella (10 districts). The administrative districts with the most diverse invasive alien plants were Gangseo-gu (8 species) and Buk-gu (8 species), which are both areas with high human interference and diverse habitats. Additional environmental information was collected for these species' habitats in Busan. The results of this research can be used to assess the current status of invasive alien plants in Busan and can provide basic data useful for effectively controlling and preventing the spread of invasive plants.

• Korean Journal of Microbiology
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• v.32 no.4
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• pp.245-251
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• 1994

Ten strains of 7 species from the genus Ganoderma, G. lucidum ATCC 64251, FP-103561-T, and ES70701, G. applanatum ATCC 44053 and FP-57035-T. G. lobatum ATCC 42985, G. resinaceum ATCC 52416, G. subamboinense var. laevisporum ATCC 52420, G. meredithae ATCC 64492, and G. microsporum ATCC 76024, were studied to discuss their phylogenetic relationships by utilizing restriction fragment length polymorphisms (RFLPs) of mitochondrial DNAs (mtDNAs). Six restriction enzymes, BamHI, BglII, EcoRI, HindIII, PvuII, and XbaI which digested mtDNAs into adequate numbers of restriction fragments for cluster analysis, were used in this study. Restriction profiles of strains for each restriction enzyme were treated as analysis characters to calculate similarity coefficients, which were converted into nucleotide sequence divergence values whose mean values were then arranged in a matrix table. This table was utilized for a phylogenetic analysis using the Neighborjoining method of the PHYLIP package to construct phylogenetic tree. Three strains of G. lucidum and two strains of G. applanatum exhibited different lineages each but one of G. applanatum strains showed a close relationship with G. lobatum, which reflected the species complexity of these species whose strains were phenotypically indistinguishable but genetically distinct. The present results suggest that the natural classification of Ganoderma needs to be considered from the viewpoints of molecular biology-based systematics as well as morphological classifications and cultural identifications for better phylogenetic conclusions.

• Korean Journal of Microbiology
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• v.43 no.4
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• pp.256-263
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• 2007

We performed the biochemical characteristics, molecular epidemiologocal analysis, and drug susceptibility test on V. vulnificus isolated from environmental sources in Incheon. For this study, 233 strains were isolated from seawater, sediment, shellfish. V. vulnificus isolates were divided into 15 biochemical groups, which were positive for ONPG and Amygdalin test. Among the 209 strains, 206 (98.6%) strains and 110 (52.6%) strains revealed positive for vvhA and viuB gene, and the viuB gene detection rates of V. vulnificus from seawater, shellfish and sediment were 48%, 48.5% and 61.6%, respectively. From disc diffusion test on 175 isolates, most of strains were sensitive to Imipenem (100.0%), Sulfamethoxazole/trimethoprim (98.9%), Tetracycline, Ciprofloxacin (98.3%), Ampicillin/sulbactam (97.1%), Ohloramphenicol (96.6%), Cefepime (94.9%) and Ceftriaxone (94.8%), multi-drug resistance rates was 31.5% of seawater, 34.4% of sediment and 29.2% of shellfish. PFGE was performed on 233 V. vulnificus isolates with the objective of investigating the extent of genetic diversity of these isolates in our region. We could find that at least 126 different PFGE patterns were generated according by 90% of similarity and 13 clusters by 58% of similarity. The major cluster was type I (44.6%) during the most of the year, and type J was frequent pattern in June and October. There were 9 distinct PFGE types in July, 8 types in August, 7 types in June, 6 types in September, 5 types in October 3 types in May and 1 type in March.