• Fisheries and Aquatic Sciences
• /
• 제11권4호
• /
• pp.209-211
• /
• 2008

Heterotrophic dinoflagellate Pfiesteria piscicida (Dinophyceae) has been claimed to produce potent ichthyotoxins that cause disorientation and eventually death of fish and other marine animals. A real-time PCR probe targeting for SSU rRNA gene was used for detection of P. piscicida in Chinhae Bay, Korea. PCR inhibitors were successfully removed by dilution of template DNA. Positive detections were shown from surface water samples indicating the presence of P. piscicida in Chinhae Bay.

• Mycobiology
• /
• 제32권4호
• /
• pp.179-185
• /
• 2004

Arbuscular mycorrhizal fungi were observed in Botrychium ternatum native in Korea. The partial small subunit(SSU) of ribosomal DNA gene from the fern roots was amplified with primers AM1/NS31. Nucleotides sequence analysis of the clones revealed that two fragments were close to Glomus proliferum and G. sinuosum. The other three DNA fragments were close to those of G. proliferum with the relatively low similarities($92{\sim}95%$) and speculated to be originated from three different species of Glomus(GLA006, GLA016, and GLA032). Five different nucleotide sequences close to three AM fungal species were found in the roots of B. ternatum native in Korea.

• Mycobiology
• /
• 제49권4호
• /
• pp.297-307
• /
• 2021

A cordycipitoid fungus infecting Hepialidae sp. in Nepal was supposed to be identical to Cordyceps liangshanensis, originally described from southwestern China, and thus, transferred to the genus Metacordyceps or Papiliomyces in previous studies. However, our multi-gene (nrSSU-nrLSU-tef-1α-rpb1-rpb2) phylogenetic and morphological studies based on the type specimen and additional collections of C. liangshanensis revealed that the fungus belongs to the genus Ophiocordyceps (Ophiocordycipitaceae). Therefore, a new combination O. liangshanensis was made, and a detailed description of this species was provided.

• 생명과학회지
• /
• 제12권4호
• /
• pp.427-432
• /
• 2002

잇바디돌김(Porptyra dentata)을 대상으로 핵의 18S ribo-somal RNA를 지령하는 유전자 즉 18S rDNA 유전자를 증폭하고, 염기서열분석을 수행하였다. 전체 18S rDNA의 exon 영역 크기는 1822 bp, intron 영역의 크기는 512 bp였다. 이들 exon과 intron 영역의 G+C함량은 각각 49%와 55%씩 나타내었다. 일본산 잇바디돌김(CenBank accession number: AB013183)의 exon 영역과의 비교에서 상동성이 97.1%에 도달하였다. 568번과 569번 염기사이의 upstream에 위치하는 intron 영 역에서는 AB013183과 52.1%의 상동성을 보였다.

• ALGAE
• /
• 제31권4호
• /
• pp.289-301
• /
• 2016

Floating debris provides substrates for dispersal of organisms by ocean currents, including algae that thrive on plastics. The 2011 earthquake and tsunami in Tohuku, Japan resulted in large amounts of debris carried by the North Pacific Current to North America from 2012 to 2016. In 2015-2016, the plastics in the debris bore a complex biota including pink algal crusts. One sample (JAW4874) was isolated into culture and a three-gene phylogeny (psbA, rbcL, and SSU) indicated it was an unknown member of the red algal class Stylonematophyceae. It is a small pulvinate crust of radiating, branched, uniseriate filaments with cells containing a single centrally suspended nucleus and a single purple to pink, multi-lobed, parietal plastid lacking a pyrenoid. Cells can be released as spores that attach and germinate to form straight filaments by transverse apical cell divisions, and subsequent longitudinal and oblique intercalary divisions produce masses of lateral branches. This alga is named Tsunamia transpacifica gen. nov. et sp. nov. Sequencing of additional samples of red algal crusts on plastics revealed another undescribed Stylonematophycean species, suggesting that these algae may be frequent on drift oceanic plastics.

• Mycobiology
• /
• 제47권4호
• /
• pp.355-367
• /
• 2019

Arthonia dokdoensis sp. nov., a lichenicolous fungus from the subcosmopolitan Arthonia molendoi complex growing on crustose thalli of species of the genus Orientophila (subfamily Xanthorioideae, Teloschistaceae), as well as the lichen species Rufoplaca toktoana sp. nov. (subfamily Caloplacoideae, Teloschistaceae) similar to Rufoplaca kaernefeltiana, both from Dokdo Islands, Republic of Korea, are described, illustrated, and compared with closely related taxa. In the phylogenetic tree of the Arthoniaceae based on 12S mtSSU and RPB2 gene sequences, the phylogenetic position of the A. dokdoensis and the relationship with the A. molendoi group are illustrated, while the position of the newly described R. toktoana is confirmed by phylogenetic tree based on ITS nrDNA data.

• 환경생물
• /
• 제39권1호
• /
• pp.32-38
• /
• 2021

Cyanobium is a genus of picoprokaryotic cyanophytes, which includes species worldwide. The present study investigated the morphology, ultrastructure, and molecular phylogeny of the unrecorded genus Cyanobium Rippka & Cohen-Bazire 1983 and species Cyanobium gracile Rippka & Cohen-Bazire 1983. A C. gracile culture from a freshwater sample collected from the Adongji pond was established by single-cell isolation. Morphological data were analyzed using light and transmission electron microscopy. C. gracile lives as solitary cells without gelatinous envelopes and is ovate, oval, or shortly rod-shaped. Thylakoids are laid along the cell walls, with three thylakoid membranes parallel to each other. Nucleoplasm was observed in the center of the cell. Molecular phylogeny performed with data from 16S small subunit ribosomal DNA gene (SSU rDNA) sequences showed that the three strains of C. gracile, including the type strain (PCC6307) and a newly recorded strain (Adong101619), formed a distinct clade with a high supporting value (maximum-likelihood=100, pp=1.00). Based on morphology and molecular data, we report the newly recorded C. gracile in Korea.

• 한국어병학회지
• /
• 제36권2호
• /
• pp.303-310
• /
• 2023

Yellow goosefish (Lophius litulon) is one of the important commercial fisheries target species in Korea, and commonly consumed as braised or stew. The microsporidian Spraguea is known to infect the nervous system of lophiid fish, forming numerous visible whitish xenomas. This parasite is commonly found in lophiid fish worldwide, but there is no information on the infection status of this parasite in Korea. We obtained commercially available chopped packs of lophiid fish from several fish markets and investigated their prevalence of infection. The isolated xenomas were crushed and purified as mature spore suspension. Microscopic observation and PCR were conducted to visualize and identify them. The host fish was also identified by DNA bar cording analysis. All the specimens were heavily infected and microscopic observation with Giemsa or Chromotrope 2R stain revealed tiny oval shapes of typical microsporidian spores. PCR analysis targeting the partial SSU rDNA showed that our specimen belongs to the genus Spraguea clade. But clear identification at the species level was not possible, due to the insufficient information of gene sequences available in GenBank. In addition, all of our host fish specimen was identified as yellow goosefish. This is the first report of a microsporidian parasite Spraguea infection in yellow goosefish from Korea.

• 식물병연구
• /
• 제29권4호
• /
• pp.420-424
• /
• 2023

2020년 제주도 동백동산 내 구실잣밤나무 수피에 고약병과 관련된 Septobasidium sp.가 발견되었다. 분리한 균주는 습실 처리하여 새로 생성된 균사에 대한 genomic DNA를 추출한 뒤 internal transcribed spacer 및 small subunit rDNA 유전자에 대해 염기서열을 밝혔으며 polymerase chain reaction-based restriction fragment length polymorphism 분석을 통해 균주들간의 분자학적 특성이 조사되었다. 이 새로운 Septobasidium sp.은 기존에 알려진 고약병들과 형태학적 및 계통학적으로 다르게 나타나 새로운 종으로 보고한다. 또한 이 고약병은 관찰 당시 주변의 다른 수목들에서는 발생하지 않고 오직 구실잣밤 나무에서만 나타나는 특성으로 기주특이성이 매우 높다는 것이 확인되었다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제14권6호
• /
• pp.880-884
• /
• 2001

Rumen microbiology research has undergone several evolutionary steps: the isolation and nutritional characterization of readily cultivated microbes; followed by the cloning and sequence analysis of individual genes relevant to key digestive processes; through to the use of small subunit ribosomal RNA (SSU rRNA) sequences for a cultivation-independent examination of microbial diversity. Our knowledge of rumen microbiology has expanded as a result, but the translation of this information into productive alterations of ruminal function has been rather limited. For instance, the cloning and characterization of cellulase genes in Escherichia coli has yielded some valuable information about this complex enzyme system in ruminal bacteria. SSU rRNA analyses have also confirmed that a considerable amount of the microbial diversity in the rumen is not represented in existing culture collections. However, we still have little idea of whether the key, and potentially rate-limiting, gene products and (or) microbial interactions have been identified. Technologies allowing high throughput nucleotide and protein sequence analysis have led to the emergence of two new fields of investigation, genomics and proteomics. Both disciplines can be further subdivided into functional and comparative lines of investigation. The massive accumulation of microbial DNA and protein sequence data, including complete genome sequences, is revolutionizing the way we examine microbial physiology and diversity. We describe here some examples of our use of genomics- and proteomics-based methods, to analyze the cellulase system of Ruminococcus flavefaciens FD-1 and explore the genome of Ruminococcus albus 8. At Illinois, we are using bacterial artificial chromosome (BAC) vectors to create libraries containing large (>75 kbases), contiguous segments of DNA from R. flavefaciens FD-1. Considering that every bacterium is not a candidate for whole genome sequencing, BAC libraries offer an attractive, alternative method to perform physical and functional analyses of a bacterium's genome. Our first plan is to use these BAC clones to determine whether or not cellulases and accessory genes in R. flavefaciens exist in clusters of orthologous genes (COGs). Proteomics is also being used to complement the BAC library/DNA sequencing approach. Proteins differentially expressed in response to carbon source are being identified by 2-D SDS-PAGE, followed by in-gel-digests and peptide mass mapping by MALDI-TOF Mass Spectrometry, as well as peptide sequencing by Edman degradation. At Ohio State, we have used a combination of functional proteomics, mutational analysis and differential display RT-PCR to obtain evidence suggesting that in addition to a cellulosome-like mechanism, R. albus 8 possesses other mechanisms for adhesion to plant surfaces. Genome walking on either side of these differentially expressed transcripts has also resulted in two interesting observations: i) a relatively large number of genes with no matches in the current databases and; ii) the identification of genes with a high level of sequence identity to those identified, until now, in the archaebacteria. Genomics and proteomics will also accelerate our understanding of microbial interactions, and allow a greater degree of in situ analyses in the future. The challenge is to utilize genomics and proteomics to improve our fundamental understanding of microbial physiology, diversity and ecology, and overcome constraints to ruminal function.