• Mycobiology
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• v.50 no.4
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• pp.203-212
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• 2022

Fungi act as important decomposers in the forest environment. They recycle essential nutrients, promote plant growth through mycorrhizal relationships, and act as food for small animals. Samples of 265 indigenous fungal species were collected from Mudeungsan National Park in 2020. These species were identified based on morphological, molecular, and phylogenetic analyses using the internal transcribed spacer (ITS), nuclear large subunit rRNA (LSU), and RNA polymerase II second largest subunit (rpb2) regions. Subsequently, seven species were identified as unrecorded species in Korea: Cordyceps cicadae, Dentocorticium bicolor, Hymenochaete nanospora, Physisporinus crataegi, Rigidoporus piceicola, Russula raoultii, and Scutellinia crinita. This study reveals their detailed macro- and microscopic morphological characteristics with phylogenetic trees to report them as unrecorded species in Korea.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.470-474
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• 2003

DNA sequence information on small-subunit rRNA gene (16S rDNA) obtained from food-poisoning bacterial culture was used to investigate the presence of bacterial pathogens in food. By reverse dot blot detection method, presence of food-poisoning bacteria could be confirmed on hybridization of digoxigenin-labeled 16S rDNA Polymerase Chain Reaction (PCR) primer product and biotin-labeled specific oligonucleotide probe. Escherichia coli, Bacillus cereus. and Salmonella sp. were used as the representative food-poisoning bacterial microorganisms. An oligonucleotide probe, based on the variable region of 16S rRNA gene, was used as the specific probe. These tools may be more useful than classic biochemical method for rapid identification of contaminated food.

• Parasites, Hosts and Diseases
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• v.60 no.1
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• pp.45-49
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• 2022

The Japanese amberjack Seriolae quinqueradiata is one of the most consumed fish species among the Koreans. However, information regarding parasitic infection in Japanese amberjack is scarce. This study described the morphological and molecular characteristics of a species of philometrid nematode, Philometroides seriolae, which was recovered from Japanese amberjack. This fish was caught in the sea of Goseong-gun, Gangwon-do, Republic of Korea (Korea). Six P. seriolae (Nematoda: Philometridae) were recovered from 2 Japanese amberjacks. These parasites were subgravid female which were 325-420 mm long and 2.95-3.27 mm wide. Furthermore, they had typical papillae distributed on their body surface with 14 papillae at the apical view. Sequence analysis of the small subunits of ribosomal RNA (SSU rRNA) showed high sequence identity (99.8%, 1,607/1,611-bp) with that of P. seriolae (GenBank accession no. FJ155811). This nematode species has been newly added to the Korean nematode fauna.

• The Korean Journal of Mycology
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• v.50 no.3
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• pp.195-204
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• 2022

A fungal strain, designated KNUF-20-NI009, was isolated from soil collected from Gunsan-si, Jeollabuk-do, Korea. The isolate showed cultural features typical of the genus Xenoroussoella. Colonies cultivated on malt extract agar were olivaceous-brown to pale olivaceous-white at the margins, with undersides of dark olivaceous to olivaceous-brown and a white margin. The conidia, with a size range of 2.7-5.1×1.6-3.3 ㎛ ($\bar{x}=3.6\times2.6{\mu}m$, n=50), were globoid to ellipsoid in shape, hyaline when immature, becoming light brown to golden-brown when mature, and characterized by 1 or 2 guttules. Multi-locus sequence analysis based on a combined dataset of internal transcribed spacer regions (ITS), large subunit rDNA (LSU), small subunit rDNA (SSU), translation elongation factor 1-alpha (TEF1α), and RNA polymerase II largest subunit (RPB2) sequences revealed KNUF-20-NI009 to be a strain of Xenoroussoella triseptata. This is the first report of this species in Korea.

• ALGAE
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• v.32 no.3
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• pp.181-187
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• 2017

During a sampling at Nokdong harbor, southern coast of Korea in January 2017, the marine diatom Coscinodiscus wailesii cells infected by a novel parasitoid nanoflagellate were observed. While the development process of the trophosomes of the parasitoid was more similar to that of Pseudopirsonia mucosa, division pattern of the auxosomes was similar to that of Pirsonia species. Phylogenetic analyses inferred from 18S rRNA gene sequences revealed that the parasitoid infecting C. wailesii fell within the cercozoan groups and branched as a sister lineage of the clade consisting of Pseudopirsonia mucosa and the undescribed Cercomonas sp. SIC7235, with the sequence dissimilarity of 7.3% with Pseudopirsonia mucosa. All of these developmental and molecular characteristics suggest that the parasitoid nanoflagellate infecting the diatom C. wailesii is a new Pseudopirsonia species.

• Korean Journal of Microbiology
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• v.44 no.4
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• pp.271-276
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• 2008

Ribosome stalling by nascent sticky peptide has been reported in several organisms across the kingdom. To test whether small subunit (SSU) rRNA is involved in this phenomenon, we developed a genetic system that utilized the specialized ribosome system to isolate SSU rRNA mutants that enable ribosomes to bypass the SecM-derived sticky peptide in protein synthesis. In this system, CAT-SecM mRNA, which encodes CAT protein containing the sticky peptide derived from SecM, is only translated by specialized ribosomes. These ribosomes were shown to transiently stall on CAT-SecM mRNA followed by the synthesis of the sticky peptide. Expression of specialized ribosomes resulted in the decreased steady-state level of CAT-SecM mRNA, which is consistent with a notion that ribosome stalling induces mRNA degradation. Isolation and characterization of SSU rRNA mutations using this genetic system that are sufficient to circumvent ribosome stalling induced by the SecM-derived sticky peptide will provide evidence of SSU rRNA function in mRNA cleavage.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.4
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• pp.266-274
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• 2000

Understanding of microbial community structure in soil-root system is necessary to use beneficial soil and rhizosphere microbes for improvement of crop production and biocontrol. The knowledge of behavior and function of microbes in soil-root system plays a key role for the application of beneficial inocula. Because the majority of the intact bacteria in soil are unable to grow on nutrient media, both culturable and nonculturable bacteria have to be studied together. In our study, culture-independent survey of bacterial community in the soil-root system of red pepper fields was conducted by the sequence analysis of three universal clone libraries of genes which code for small-subunit rRNA (rDNA). Universal small subunit rRNA primers were used to amplify DNA extracted from each sample and PCR products were cloned into pGEM-T. Out of 27 clones sequenced, 25 clones were from domain bacteria. Two of the rDNA sequences were derived from eukaryotic organelles. Within the domain bacteria, several kingdoms were represented : the Proteobacteria (16 clones). Cytophyga-Flexibacter-Bacteroides group (2 clones). the high G+C content gram-positive group(1 clone) and 4 unknown clones.

• Parasites, Hosts and Diseases
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• v.44 no.1 s.137
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• pp.27-33
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• 2006

Two species of Cryptosporidium are known to infect man; C. hominis which shows anthroponotic transmission between humans, and C. parvum which shows zoonotic transmission between animals or between animals and man. In this study, we focused on identifying genotypes of Cryptosporidium prevalent among inhabitants and domestic animals (cattle and goats), to elucidate transmittal routes in a known endemic area in Hwasun-gun, Jeollanam-do, Republic of Korea. The existence of Cryptosporidium oocysts was confirmed using a modified ZiehlNeelsen stain. Human infections were found in 7 $(25.9\%)$ of 27 people examined. Cattle cryptosporidiosis cases constituted 7 $(41.2\%)$ of 17 examined, and goat cases 3 $(42.9\%)$ of 7 examined. Species characterizations were performed on the small subunit of the rRNA gene using both PCR-RFLP and sequence analysis. Most of the human isolates were mixtures of C. hominis and C. parvum genotypes and similar PCR-RFLP patterns were observed in cattle and goat isolates. However, sequence analyses identified only C. hominis in all isolates examined. The natural infection of cattle and goats with C. hominis is a new and unique finding in the present study. It is suggested that human cryptosporidiosis in the studied area is caused by mixtures of C. hominis and C. parvum oocysts originating from both inhabitants and domestic animals.

• Parasites, Hosts and Diseases
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• v.47 no.3
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• pp.293-297
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• 2009

Improved methods for detection of Cryptosporidium oocysts in environmental and clinical samples are urgently needed to improve detection of cryptosporidiosis. We compared the sensitivity of 7 PCR primer sets for detection of Cryptosporidium parvum. Each target gene was amplified by PCR or nested PCR with serially diluted DNA extracted from purified C. parvum oocysts. The target genes included Cryptosporidium oocyst wall protein (COWP), small subunit ribosomal RNA (SSU rRNA), and random amplified polymorphic DNA. The detection limit of the PCR method ranged from $10^3$ to $10^4$ oocysts, and the nested PCR method was able to detect $10^0$ to $10^2$ oocysts. A second-round amplification of target genes showed that the nested primer set specific for the COWP gene proved to be the most sensitive one compared to the other primer sets tested in this study and would therefore be useful for the detection of C. parvum.

• Parasites, Hosts and Diseases
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• v.53 no.2
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• pp.237-242
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• 2015

Analysis of ancient DNA (aDNA) extracted from Ascaris is very important for understanding the phylogenetic lineage of the parasite species. When aDNAs obtained from a Joseon tomb (SN2-19-1) coprolite in which Ascaris eggs were identified were amplified with primers for cytochrome b (cyt b) and 18S small subunit ribosomal RNA (18S rRNA) gene, the outcome exhibited Ascaris specific amplicon bands. By cloning, sequencing, and analysis of the amplified DNA, we obtained information valuable for comprehending genetic lineage of Ascaris prevalent among pre-modern Joseon peoples.