• Mycobiology
• /
• v.47 no.2
• /
• pp.191-199
• /
• 2019

Most of lichens are formed by Ascomycota, less than 1% are lichenized Basidiomycota. The flora investigation of lichenized Ascomycota of South Korea has been well studied in the past three decades; however, prior to this study, none of basidiolichens was discovered. During the recent excursion, an unexpected clavarioid basidiolichen, Sulzbacheromyces sinensis was collected. Morphology and ecology has been recorded in detail. DNA was extracted, and ITS, 18S, 28S nuclear rDNA were generated. In order to further confirm the systematic position of the Korean specimens, maximum likelihood and Bayesian inference analysis including all the species of the order Lepidostromatales were conducted based on the ITS. As a result, the phylogenetic tree of the order Lepidostromatales was reconstructed, which differed from the previous studies. The inferred phylogenetic tree showed that species of Sulzbacheromyces in three different continents (Asia, South Africa and South America) were separated into three clades with support. In this study, the species worldwide distribution map of Lepidostromatales was illustrated, and S. sinensis had a widest distribution range (paleotropical extend to the Sino-Japanese) than other species (paleotropical or neotropical). Prior to this study, the range of distribution, southernmost and northernmost points and the fruiting time of S. sinensis were recorded, and the genus Sulzbacheromyces was firstly reported from Korean peninsula and Philippines.

• Korean Journal of Plant Taxonomy
• /
• v.45 no.3
• /
• pp.243-253
• /
• 2015

Series Chinensis, Genus Iris, endemic to the far regions of East Asia, consists of four species and related varieties. This series is divided into two major groups (I. rossii and I. minutiaurea complex). In this study, the ITS region and matK gene sequences within nuclear ribosomal DNA and plastid DNA were analyzed in order to investigate the phylogenetic relationships among the I. minutiaurea complex (I. minutiaurea, I. odaesanensis, and I. koreana) and the taxonomic identities of a putative hybrid in Mt. Palgong. In the internal transcribed spacer (ITS1, 5.8S, and ITS2) region, a total of 106 cloned genomic sequences from three taxa were obtained to study the intragenomic polymorphisms of the ITS regions. Three taxa revealed high levels of intragenomic polymorphisms, indicative of incomplete nrDNA concerted evolution. This incomplete ITS concerted evolution in the series Chinensis may be linked to the recent species divergence and frequent interspecies hybridization of the series Chinensis. In the matK gene, three taxa were fairly separated by eleven variable sites. In eight individuals collected on Mt. Palgong, putative hybrids between I. odaesanensis and I. minutiaurea were clustered in the I. minutiaurea clade in the NJ (neighbor-joining) tree based on the matK gene. However, in the ITS tree, some of them were clustered in the I. odaesanensis clade and others were clustered in the I. minutiaurea clade. Therefore, the individuals on Mt. Palgong were formed by the hybridization between two taxa (I. odaesanensis and I. minutiaurea) and not through the lineage of I. koreana.

• Journal of Microbiology and Biotechnology
• /
• v.22 no.9
• /
• pp.1214-1217
• /
• 2012

One Helicosporium strain, isolated from a wilted chestnut tree, evidenced in vitro antimicrobial activity against various types of bacteria and fungi, and generated a diffusible pigment. The antimicrobial compounds and the diffusible pigment of the Helicosporium sp. isolate were purified via solvent fractionation, column chromatography, and recycling preparative chromatography. Both the major antimicrobial compound and the diffusible pigment were identified as 2-methylresorcinol via nuclear magnetic resonance spectroscopy. Therefore, 2-methylresorcinol, a diffusible pigment generated by Helicosporium sp., appears to be an active antimicrobial principle. This pigment also exhibited considerable cytotoxicity against mammalian cells.

• Journal of Microbiology
• /
• v.34 no.4
• /
• pp.295-299
• /
• 1996

To infer phylogenetic relationships between species of Trichaptum (Polyporaceae), RFLP analyses of PCR-amplified DNAs were accomplished. Regions coding for ITSs of nuclear SSU rRNA genes and for mitochondrial SSU rRNA genes from thirteen strains of four Trichaptum species (T. abietinum, T. biforme, T. fusco-violaceum, and T. laricinum) were amplified and digested with eight restriction enzymes. All the fragmentation patterns were characterized and coded as 0/1 for the absence/presence of fragments. A phylogenetic tree based on the combined data sets was constructed using the Dollo parsimony method. While every two strains of T. abietinum, T. biforme, T. fusco-violaceum, and T. laricinum formed an independent group, the other strains of T. abietimum and T. fusco-violaceum made mixed groupings among compared strains. It is inferred that T. abietinum and T. fusco-violaceum have more variations, possibly geographic or physiological ones, than other species in the genus.

• Journal of Plant Biotechnology
• /
• v.39 no.1
• /
• pp.75-80
• /
• 2012

$Kalopanax$ $pictus$ is a long-lived deciduous perennial tree in the family Araliaceae mainly distributed in the East Asia. In Korea, this species is of ecological and medical importance. Because typical populations of this species are small and distributed in patches, $K.$ $pictus$ has been considered as a narrow habitat species. To understand the genetic diversity and population structure of this species, the sequence variation of the nuclear ribosomal DNA (nrDNA) internal transcribed spacer (ITS) region was analyzed among 18 different $K.$ $pictus$ populations in the present investigation. The nrDNA ITS sequences of Korean populations investigated in this study showed identical of 616 bp in length, and no any nucleotide variation was found in the entire nrDNA ITS region sequence. This result suggested that the $K.$ $pictus$ populations in Korea might belong to the same isolate, and no mutation was found in the nrDNA ITS region. Compared with other known ITS sequence sources from $K.$ $pictus$ populations, only four variable nucleotide sites were found within the entire ITS region. Very narrow genetic diversity appearing in the population level of $K.$ $pictus$ makes us hypothesize that their relatively isolated habitats. The long-lived traits might be one main reason. However, another probability was that the nr-DNA ITS region might be noneffective in classifying populations of $K.$ $pictus$. Thus, to further understand the phylogenetic relationship of $K.$ $pictus$ populations, more samplings should be performed based on more DNA sequences.

• Nuclear Engineering and Technology
• /
• v.39 no.1
• /
• pp.31-42
• /
• 2007

Energy supply is increasingly showing up as a major issue for electricity supply, transportation, settlement, and process heat industrial supply including hydrogen production. Nuclear power is part of the solution. For electricity supply, as exemplified in Finland and France, the EPR brings an immediate answer; HTR could bring another solution in some specific cases. For other supply, mostly heat, the HTR brings a solution inaccessible to conventional nuclear power plants for very high or even high temperature. As fossil fuels costs increase and efforts to avoid generation of Greenhouse gases are implemented, a market for nuclear generated process heat will be developed. Following active developments in the 80's, HTR have been put on the back burner up to 5 years ago. Light water reactors are widely dominating the nuclear production field today. However, interest in the HTR technology was renewed in the past few years. Several commercial projects are actively promoted, most of them aiming at electricity production. ANTARES is today AREVA's response to the cogeneration market. It distinguishes itself from other concepts with its indirect cycle design powering a combined cycle power plant. Several reasons support this design choice, one of the most important of which is the design flexibility to adapt readily to combined heat and power applications. From the start, AREVA made the choice of such flexibility with the belief that the HTR market is not so much in competition with LWR in the sole electricity market but in the specific added value market of cogeneration and process heat. In view of the volatility of the costs of fossil fuels, AREVA's choice brings to the large industrial heat applications the fuel cost predictability of nuclear fuel with the efficiency of a high temperature heat source tree of Greenhouse gases emissions. The ANTARES module produces 600 MWth which can be split into the required process heat, the remaining power drives an adapted prorated electric plant. Depending on the process heat temperature and power needs, up to 80% of the nuclear heat is converted into useful power. An important feature of the design is the standardization of the heat source, as independent as possible of the process heat application. This should expedite licensing. The essential conditions for success include: ${\bullet}$ Timely adapted licensing process and regulations, codes and standards for such application and design ${\bullet}$ An industry oriented R&D program to meet the technological challenges making the best use of the international collaboration. Gen IV could be the vector ${\bullet}$ Identification of an end user(or a consortium of) willing to fund a FOAK

• Korean Journal of Plant Taxonomy
• /
• v.50 no.3
• /
• pp.253-261
• /
• 2020

Carex splendentissima U. Kang & J. M. Chung, endemic to the Korean peninsula, is characterized by staminate terminal spikes and glabrous elliptic perigynia. Based on its broad leaves, androgynous spikes, and tri-stigmatic features, the species has been placed in Carex sect. Siderostictae Franch. ex Ohwi, an East Asian section and a basal group in the genus. To clarify the monophyly and phylogenetic position of the species, a molecular study using the internal transcribed spacer region of nuclear ribosomal DNA and chloroplast DNA (trnL-F) data was conducted. The DNA sequence data of ten taxa in sect. Siderostictae and closely related taxa (two taxa in sect. Surculosae) with outgroups were analyzed based on maximum parsimony and maximum likelihood (ML) criteria. In the analyses, C. splendentissima was monophyletic and placed within the Siderostictae clade (sect. Siderostictae + two species of sect. Surculosae), forming a clade with C. ciliatomarginata and C. pachygyna (endemic to Japan). The clade (C. splendentissima + C. ciliatomarginata + C. pachygyna) shows evidence of diploidy. Furthermore, C. splendentissima is a sister to C. ciliatomarginata in the ML tree, and the two taxa have staminate terminal spikes. This study also updates the distribution of C. splendentissima and provides keys to the four Korean taxa in sect. Siderostictae. To conserve the endemic species C. splendentissima, further research on its genetic and ecological features should be conducted at the population level.

• Korean Journal of Plant Taxonomy
• /
• v.35 no.1
• /
• pp.7-23
• /
• 2005

Molecular phylogenetic studies were conducted to evaluate interspecific relationships in 40 populations of Viola including 35 Korean taxa, four Japanese populations and one outgroup using nuclear ribosomal ITS sequences. The phylogenetic analyses were conducted using parsimony and neighbor-joining methods. Subsection Trigonocarpae of section Nomimium appeared as the most basal clade within the Korean Viola. Section Dischidium and Chamaemelanium was monophyletidbootstrap 100%) and placed between subsect. Trigonocarpae and three other subsections of sect. Nomimium. Sect. Nomimium was paraphyletic. Although each subsectional grouping was in accordance with previous infrageneric classification based on morphological characters, yet discordance remained at the series level. Two evolutionary trends observed in the ITS tree were as follows. First, subsect. Trigonocarpae(x=10) was derived from the outgroup(x=6); Second, subsects. Bilobatae and Vaginatae(x=10 or 12), and subsect. Patellares(x=12) of sect. Nomimium were originated from sects. Dischidium and Chamaemelanium(x=6). Viola albida complex including three very closely related taxa was recognized as independent group within subsect. Patellares in parsimony tree. This result suggested that they should be treated as a taxa in series Pinnatae. Phylogenetic position of a putative hybrid species, Viola woosanensis was not supported with previous morphological hypothesis.

• Nuclear Engineering and Technology
• /
• v.21 no.1
• /
• pp.1-11
• /
• 1989

Numerous losses of decay heat removal capability have occurred at U during stutodwn while its significance to safety is needless to say. A study is carried out as an attempt to assess what could be done to lower the frequency of these events and to mitigate their consequences in the unlikely event that one occurs. The shutdown risk model is developed and analyzed using Event/Fault Tree for the typical pressurized water reactor. The human cognitive reliability (HCR) model, two-stage bayesian approach and staircase function model are used to estimate human reliability, initiating event frequency and offsite power non-recovery probability given loss of offsite power, respectively. The results of this study indicate that the risk of a Pm at shutdown is not much lower than the risk when the plant is operating. By examining the dominant accident sequences obtained, several design deficiencies are identified and it is found that some proposed changes lead to significant reduction in core damage frequency due to loss of cooling events.

• Korean Journal of Plant Resources
• /
• v.23 no.4
• /
• pp.293-302
• /
• 2010

Taxa of Artemisia collected in Korea were constructed by molecular phylogenetic analysis based on the internal transcribed spacer(ITS) regions of nrDNA. The length of the ITS sequences aligned using the clustal X program was 636~643 bp, and the lengths of the ITS1 and ITS2 regions were 251~255 bp and 217~222 bp, respectively. The total number of variable sites was 95 for the entire sequence, and a parsimony- informative site represented an efficacious site in ITS1 rather than in ITS2. The maximum parsimony tree as calculated by the MEGA 4 program was clustered into five clades. The taxa(A. capillaris, A. japonica var. japonica, A. japonica var. hallaisanensis, A. japonica subsp. littoricora) degenerated ovary of clade 1 was supported as the subgenus Dracunculus by Ling's classification system. The results show that A. nakaii and A. fukudo were quite similar genetically(Boostrap 99%) and that the scientific name of Korean A. dubia should be reconsidered. A. sp. distributed in Ganghwa province was grouped with A. argyi(Boostrap 89%). These results suggest that the molecular techniques used in this study could be useful for the phylogenetic analysis of Korean Artemisia herbs having variations in their morphological characteristics.