• Mycobiology
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• 제50권4호
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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.

• 한국식품과학회지
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• 제35권3호
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• pp.470-474
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• 2003

식중독은 세균에 의한 발병이 대부분이다. 따라서 식품에서 식중독 원인균을 신속하게 탐색하게 식중독으로부터의 되면 피해를 줄일 수 있을 것이다. 고전적인 식중독 원인균 탐색은 증균, 선택적 배지를 이용한 isolation, 생화학적 특징을 활용하는 분석이 있으나 많은 시간이 소요되는 단점을 갖고 있었다. 본 연구는 16S rRNA gene(16S rDNA)로부터 얻은 DNA 염기 서열을 이용 식중독 원인균의 특이적 oligonucleotide probe을 제작 reverse dot blot hybridization과 PCR 방법을 이용하여 고전적인 방법보다 빠른 시간 내에 식품에서 원인균을 탐색 할 수 있었다. 우유를 인공적으로 본 연구에서 사용한 균주로 오염시킨 후 DNA를 추출하여 PCR 증폭산물과 oligonucleotide probe를 hybridization 시킨 결과 oligonucleotide probe를 hybridization 시킨 결과 oligonucleotide probe가 위치한 곳에서 발색 반응이 나타났다. 본 연구에서 본 연구를 통해 DNA microchip으로 활용 짧은 시간 내에 많은 종류의 식중독 원인균을 탐색 할 수 있는 가능성을 확인하였다.

• Parasites, Hosts and Diseases
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• 제60권1호
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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.

• 한국균학회지
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• 제50권3호
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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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• 제32권3호
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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.

• 미생물학회지
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• 제44권4호
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• pp.271-276
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• 2008

최근 단백질 합성 과정 중 라이보솜의 일시적인 정지에 의한 라이보솜의 A자리에서 전사체가 분해되는 현상이 여러 생명체에서 보고되었다. 이러한 현상이 라이보솜의 작은 소단위체를 이루고 있는 SSU rRNA의 기능과 관련 있는지를 알아보기 위해, SecM에서 유래한 접착펩타이드에 의한 라이보솜 정지를 우회하는 SSU rRNA 돌연변이체 발굴을 위한 유전학적 시스템을 개발하였다. 이 시스템에서는 SecM에서 유래한 접착펩타이를 포함하는 CAT 단백질을 코딩하는 CAT-SecM 전사체가 플라스미드에서 유래한 SSU rRNA를 포함한 재조합 라이보솜에 의해서만 해독된다. 이러한 재조합 라이보솜은 접착펩타이드를 합성한 후 CAT-SecM mRNA 상에서 일시 정체하며, 재조합 라이보솜의 발현은 이 전사체의 양을 감소시키는 것을 확인하였다. 이러한 결과는 개발된 시스템을 이용해 라이보솜 검지를 우회하는 SSU rRNA 돌연변이체의 선별이 가능하다는 것을 보여주며, 이러한 변이체에 대한 연구는 단백질 합성 단계에서 일어나는 라이보솜 정지와 전사체 절단 현상에 있어서, SSU rRNA의 역할을 규명하는데 기여할 것이다.

• 한국토양비료학회지
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• 제33권4호
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• pp.266-274
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• 2000

토양과 작물근계의 유용미생물을 이용하여 작물생산성을 증대하고 병충해의 생물학적 방제를 위해서는 토양-근계의 미생물군집을 분석하고 그 기능을 밝히는 것이 전제가 되어야한다. 그러나 희석평판법으로는 극히 일부분만이 배양된다는 점을 고려할 때, 생존하지만 배양 불가능한 미생물의 군집 분석도 반드시 병행할 필요가 있다. 따라서 본 연구에서는, 고추재배지의 토양, 근권토양, 근면의 세균군집 구조해석을 위해서, 배양을 거치지 않고 각 시료로부터 직접 DNA를 추출하여 PCR증폭, 16S rDNA cloning, sequencing, 계통 해석을 행했다. 그 결과, 토양중에는 근권세균보다 미지의 동정이 되지 않는 세균이 우점하고 있었다. 27 clones 중에서 16 clones이 그램음성세균의 대표격인 Proteobacteria였으며, 방선균 등이 속해있는 고(高) G+C 그램양성세균군은 1 clone이 검출되었다. 그 외는 CFB 군이 2 clones, Verrucomicrobia가 1 clone이었고, Nitrospira가 1 clone이었으며 4 clones은 어느 군에도 속하지 않았다.

• Parasites, Hosts and Diseases
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• 제44권1호
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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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• 제47권3호
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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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• 제53권2호
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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.