• Journal of the Korean Electrochemical Society
• /
• v.8 no.2
• /
• pp.77-81
• /
• 2005

Porous-composite electrodes have been developed using silica gel, which reduce carbon aerogel usage with high cost. Silica gel powder was added to the carbon aerogel to simplify the manufacturing procedure and to increase the wet-ability, the mechanical strength and the CDI efficiency. Porous composite electrodes composed of carbon aerogel and silica gel powder were prepared by paste rolling method. Carbon aerosol composite electrodes with $10\times10cm^2$ are placed face to face between spacers, and assembled the four-stage series cells for CDI process. Each stage is composed of 45 cells. Four-stage series cells (flow through cells) for CDI process are put in continuous-system reactor containing 1,000ml-NaCl solution bath of 1,000 ppm. The four-stage series cells with carbon aerogel electrodes are charged at 1.2V and are discharged at 0.001V, and then read the current. Conclusively, removal efficiencies of ions using the four-stage series cells composed of carbon aerogel composite electrodes show good removal efficiency of $99\%$ respectively.

• The Korean Journal of Mycology
• /
• v.42 no.4
• /
• pp.269-275
• /
• 2014

Halophytes of seven species, Carex scabrifolia Steud., Limonium tetragonum Bullock, Salicornia europaea L., Suaeda glauca Bunge, Suaeda japonica Makino, Suaeda maritima Dumort., and Triglochin maritimum L. were collected from the Taean Peninsula. Thirty-seven endophytic fungi were isolated from the root of halophytes, and analyzed using the DNA sequences of internal transcribed spacers (ITS). The diversity of all endophytic fungi was analyzed using diversity indices. The endophytic fungi associated with the halophytes belonged to seven orders; Eurotiales (78%), Capnodiales (5%), Hypocreales (5%), Agaricales (3%), Corticiales (3%), Glomerellales (3%), and Pleosporales (3%). At the phylum level, the endophytic fungi were composed of Ascomycota and Basidiomycota. At the genus level, Alternaria, Aspergillus, Cladosporium, Paecilomyces, Penicillium, Phanerochaete, Schizophyllum, Talaromyces, and Verticillium were confirmed. Among them, Penicillium was the most abundant in the roots of the halophytes. This study analyzed the distribution and diversity of endophytic fungi on halophytes in the Taean Peninsula.

• The Korean Journal of Mycology
• /
• v.42 no.4
• /
• pp.353-356
• /
• 2014

In August 2013, brown rot was observed on cherry fruits (Prunus avium L.) in Hwaseong city, Korea. Fruit rot first appears as small, circular brown spots that increase rapidly in size causing the entire fruit to rot. Grayish spores appear in tufts on rotted areas. Based on these morphological characteristics, the two isolates were identified as Monilinia fructicola. Molecular analysis of 5.8S subunit and flanking internal transcribed spacers (ITS1 and ITS2) was performed to confirm the identification. The ITS sequences had 100% identity with those of other reference M. fructicola isolates of NCBI GenBank. Pathogenicity was tested using spore suspension inoculation on wounded or unwounded cherry fruits. The lesions were observed on wounded and unwounded fruits after inoculation for 7 days. This is the first report on M. fructicola causing brown rot on cherry fruits in Korea.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.34 no.6
• /
• pp.426-432
• /
• 2021

Injection molding is used in many industrial fields such as home appliances, vehicle parts, and electronic device parts because various resins can be molded, leading to mass production of complex shapes. Generally, the empirical prediction method is used to set the initial processing conditions of injection molding. However, this approach requires a lot of cost and its presented solution is not accurate. In this paper, injection molding was simulated through the Moldflow^TM in order to manufacture the spacer for gas insulated switch. Through the simulation, the flow of the resin with respect to the diameter of the inlet was analyzed. It was found that the process was possible at a higher resin temperature as the diameter of the inlet increased. In addition, through thermal analysis during injection of the resin, it was confirmed that a stagnation phenomenon occurred at the insert portion during injection molding, and the temperature of the resin was higher than that of the mold. As in this paper, if the spacer is manufactured by optimizing the injection hole and the temperature of the injection process based on simulation, it is expected that the spacer can be manufactured with high productivity.

• Korean Journal of Veterinary Service
• /
• v.42 no.3
• /
• pp.161-167
• /
• 2019

The poultry red mite (PRM), Dermanyssus gallinae, causes great economic losses to poultry industries in Korea. The molecular epidemiological characterization of PRM has been investigated in some countries, but those analysis has been not conducted yet in Korea. The aim of this study is to determine the genetic diversity of PRMs in Korea compared with those from other countries. Here, 13 PRM samples collected from Korea were analyzed with a part of the mitochondrial cytochrome oxidase subunit I (COI) gene and nuclear internal transcribed spacers (ITS) region. All the samples showed an identical COI sequence, which has also been reported in European countries and Japan. Phylogenetic diversity analysis showed that the mites from Korea were genetically related to those in other countries. The nuclear ITS region sequences were classified into three sequence types. Additionally, one of the ITS sequences was an intermediate type, implying that a hybridization event occurred among the mite populations in Korea. These findings suggested PRMs from Korea showed low genetic diversity with respect to mitochondrial COI gene, but three different populations inhabited in Korea with respect to nuclear ITS region sequences.

• Korean Journal of Plant Taxonomy
• /
• v.53 no.2
• /
• pp.157-165
• /
• 2023

Paraphlomis koreana (Lamiaceae) was newly named and added to Korean flora in 2014. Paraphlomis belongs to the tribe Paraphlomideae, along with Ajugoides and Matsumurella. However, a recent study has suggested that P. koreana is morphologically similar to Matsumurella chinensis, making them difficult to distinguish from each other. Therefore, we aimed to examine the phylogenetic placement of P. koreana within the tribe and compare its genetic relationship with M. chinensis. We sequenced an additional complete plastid genome for an individual of P. koreana and generated sequences of nuclear ribosomal (nr) DNA regions of internal and external transcribed spacers (ITS and ETS) for two individuals of P. koreana. Maximum likelihood analyses based on two nrDNA regions (ITS and ETS) and four plastid DNA markers (rpl16 intron, rpl32-trnL, rps16 intron, and trnL-F) covering 13 Paraphlomis species and M. chinensis were conducted. Phylogenetic analyses concordantly supported that P. koreana forms a monophyletic group with M. chinensis. Moreover, our study revealed that P. koreana includes nrDNA sequences of M. chinensis as minor intra-individual variants, suggesting that the genetic divergence between the two taxa is incomplete and may represent intraspecific variation rather than distinct species. In conclusion, our findings suggest that the independent species status of P. koreana within Paraphlomis should be reconsidered.

• The Plant Pathology Journal
• /
• v.39 no.4
• /
• pp.384-396
• /
• 2023

Colletotrichum acutatum species complex is one of the most important groups in the genus Colletotrichum with a high species diversity and a wide range of host plants. C. acutatum and related species have been collected from different plants and locations in Korea and deposited into the Korean Agricultural Culture Collection (KACC), National Institute of Agricultural Sciences since the 1990s. These fungal isolates were previously identified based mainly on morphological characteristics, and a limitation of molecular data was provided. To confirm the identification of species, 64 C. acutatum species complex isolates in KACC were used in this study for DNA sequence analyses of six loci: nuclear ribosomal internal transcribed spacers (ITS), betatubulin 2 (TUB2), histone-3 (HIS3), glyceraldehyde3-phosphate dehydrogenase (GAPDH), chitin synthase 1 (CHS-1), and actin (ACT). The molecular analysis revealed that they were identified in six different species of C. fioriniae (24 isolates), C. nymphaeae (21 isolates), C. scovillei (12 isolates), C. chrysanthemi (three isolates), C. lupini (two isolates), and C. godetiae (one isolate), and a novel species candidate. We compared the hosts of KACC isolates with "The List of Plant Diseases in Korea", previous reports in Korea and global reports and found that 23 combinations between hosts and pathogens could be newly reported in Korea after pathogenicity tests, and 12 of these have not been recorded in the world.

• Mycobiology
• /
• v.51 no.6
• /
• pp.401-409
• /
• 2023

Nigrospora (Xylariales, Apiosporaceae) consists of species of terrestrial plant endophytes and pathogens. Nigrospora has also been reported in marine environments such as mangroves, sea fans, and macroalgae. However, limited research has been conducted on Nigrospora associated with macroalgae. Here, we isolated Nigrospora species from three types of algae (brown, green, and red algae) from Korean islands (Chuja, Jeju, and Ulleung) based on phylogenetic analyses of multigenetic markers: the internal transcribed spacers (ITS), beta-tubulin (BenA), and translation elongation factor 1 (TEF1-α). A total of 17 Nigrospora strains were isolated from macroalgae and identified as nine distinct species. The majority of Nigrospora species (seven) were found on brown algae, followed by red algae (three), and then green algae (two). To our understanding, this study represents the first account of N. cooperae, N. covidalis, N. guilinensis, N. lacticolonia, N. osmanthi, N. pyriformis, and N. rubi occurring in marine environments. Additionally, this study provides the first report of the occurrence of N. cooperae, N. covidalis, N. guilinensis, N. lacticolonia, and N. osmanthi in South Korea. This study will provide valuable insights for future research exploring the functions of fungi in macroalgal communities.

• The Korean Journal of Mycology
• /
• v.27 no.2 s.89
• /
• pp.124-131
• /
• 1999

This study was carried out to identify the phylogenetic relationship among Phellinus species by comparing the DNA sequences of the 5.8S ribosomal DNA (rDNA) and the internal transcribed spacers (ITSs), ITS1 and ITS2 regions. Two primers from the 3' end of 18S rDNA and the 5' end of 28S rDNA sequences were chosen to amplify the specific ITS regions of Phellinus spp. Phellinus strains used in the study were divided into four clusters by the phylogenetic tree based on the amplified regions of ITS and 5.8S rDNA sequences. The first cluster consist of Phellinus hartigii IMSNU 32041 and Phellinus robustus IMSNU 32068, and the second cluster consists of Phellinus linteus strains and Phellinus weirianus IMSNU 32021. Phellinus laevigatus KCTC 6229, KCTC 6230 and Phellinus igniarius KCTC 6227, KCTC 6228 belong to the third cluster. Finally, Phellinus chrysoloma KCTC 6225 and Phellinus chrysoloma KCTC 6226 are the fourth cluster. In the second cluster the differentiation between Phellinus linteus strains and Phellinus weirianus species were not possible by the comparison of the ITS sequences. These results revealed that Phellinus linteus and Phellinus weirianus cannot be established the concept of species level only by the ITS sequences. Therefore, both physiological and molecular biological methods as well as the sequences of type strains are necessary to classify the strains of these two species accurately. The comparison of the ITS sequences of four Phellinus species indicated that the sequences of the ITS1 generally are more divergent than those of the ITS2. Although the ITS sequences are varied in some species, the conserved regions in both ITS1 and ITS2 are useful tool to differentiate the species. Phellinus linteus and related species have their specific sequences in the ITS1 compared to the other species.

• Journal of Life Science
• /
• v.12 no.6
• /
• pp.821-834
• /
• 2002

In order to measure the inter- and intraspecific genetic divergences within the genus Alexandrium, the variations within the internal transcribed spacer (ITS1 and ITS2) regions and 5.85 ribosomal RNA gene of eight Alexandrium species were examined for 33 strains from diverse geographical locations by direct sequencing. Five isolates of A. tamarense (AT-2, AT-6, AT-10, AT-A and AT-B) from Jinhae Bay, Korea were found to be completely identical to a Japanese strain OFX151-A. The length of the amplified ITSI-5.85-ITS2 region varied from 481 nucleotides (in A. margalefi) to 528 nucleotides (in A. affine CU1-1). ITS1 and ITS2 nucleotide lengths were negatively correlated, whereas a positive correlation was found between their G＋C content. The degree of sequence divergence ranged from 0.3% (1 bp) to a maximum of 53% (305 Up). Pairwise sequence comparisons revealed a small degree of divergence between A. tamarense and A. Pundyense isolates (1.2 - 2.3% ＝ 6-12 bp), but a high degree of divergence between A. tamarense and A. catenella (19.8% ＝ 102 bp), and between A. catenella and A. Pundyense (19.7%). Although most nodes were weakly supported by bootstrap values, some types tend to form independent molecular groups. A. catenella isolates also formed an independent molecular sub-group, with relaticula strong bootstrap values (94% or 85% and 79% or 98%, respectively in PAUP and NJ trees). Interestingly, A. cohorticula and A. frateculus always clustered within the same sub-group, this result being supported by strong bootstrap values. Our results indicate that the ITS regions provide useful informations on hierarchical population genetic structure and a high phylogenetic resolution in intraspecific and interspecific Alexandrium population.