• Molecules and Cells
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• 제44권8호
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• pp.602-612
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• 2021

DNA methylation is an important epigenetic mechanism affecting genome structure, gene regulation, and the silencing of transposable elements. Cell- and tissue-specific methylation patterns are critical for differentiation and development in eukaryotes. Dynamic spatiotemporal methylation data in these cells or tissues is, therefore, of great interest. However, the construction of bisulfite sequencing libraries can be challenging if the starting material is limited or the genome size is small, such as in Arabidopsis. Here, we describe detailed methods for the purification of Arabidopsis embryos at all stages, and the construction of comprehensive bisulfite libraries from small quantities of input. We constructed bisulfite libraries by releasing embryos from intact seeds, using a different approach for each developmental stage, and manually picking single-embryo with microcapillaries. From these libraries, reliable Arabidopsis methylome data were collected allowing, on average, 11-fold coverage of the genome using as few as five globular, heart, and torpedo embryos as raw input material without the need for DNA purification step. On the other hand, purified DNA from as few as eight bending torpedo embryos or a single mature embryo is sufficient for library construction when RNase A is treated before DNA extraction. This method can be broadly applied to cells from different tissues or cells from other model organisms. Methylome construction can be achieved using a minimal amount of input material using our method; thereby, it has the potential to increase our understanding of dynamic spatiotemporal methylation patterns in model organisms.

• Molecules and Cells
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• 제42권5호
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• pp.379-385
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• 2019

Non-coding RNAs (ncRNAs) comprise various RNA species, including small ncRNAs and long ncRNAs (lncRNAs). ncRNAs regulate various cellular processes, including transcription and translation of target messenger RNAs. Recent studies also indicate that ncRNAs affect organismal aging and conversely aging influences ncRNA levels. In this review, we discuss our current understanding of the roles of ncRNAs in aging and longevity, focusing on recent advances using the roundworm Caenorhabditis elegans. Expression of various ncRNAs, including microRNA (miRNA), tRNA-derived small RNA (tsRNA), ribosomal RNA (rRNA), PIWI-interacting RNA (piRNA), circular RNA (circRNA), and lncRNA, is altered during aging in C. elegans. Genetic modulation of specific ncRNAs affects longevity and aging rates by modulating established aging-regulating protein factors. Because many aging-regulating mechanisms in C. elegans are evolutionarily conserved, these studies will provide key information regarding how ncRNAs modulate aging and lifespan in complex organisms, including mammals.

• BMB Reports
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• 제56권2호
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• pp.49-55
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• 2023

Aging is characterized by a gradual decline in biological functions, leading to the increased probability of diseases and deaths in organisms. Previous studies have identified biological factors that modulate aging and lifespan, including non-coding RNAs (ncRNAs). Here, we review the relationship between aging and tRNA-derived small RNAs (tsRNAs), ncRNAs that are generated from the cleavage of tRNAs. We describe age-dependent changes in tsRNA levels and their functions in age-related diseases, such as cancer and neurodegenerative diseases. We also discuss the association of tsRNAs with aging-regulating processes, including mitochondrial respiration and reduced mRNA translation. We cover recent findings regarding the potential roles of tsRNAs in cellular senescence, a major cause of organismal aging. Overall, our review will provide useful information for understanding the roles of tsRNAs in aging and age-associated diseases.

• 한국어류학회지
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• 제35권1호
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• pp.30-38
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• 2023

쌀미꾸리 Lefua costata의 섭식생태를 밝히기 위해 2013년 1월부터 12월까지 강원도 강릉시 옥계면 남양리에서 조사를 실시하였다. 쌀미꾸리는 주로 수온 5℃ 이상 되는 3월부터 12월까지 섭식을 하였고, 섭식률은 4~5월, 9~10월에 정점을 보였다. 위 내용물을 상대중요성지수(IRI)로 분석한 결과, 주로 절지동물문(Arthropoda) 곤충강(Insecta)의 파리목(Diptera, 77.1%), 하루살이목(Ephemeroptera, 20.3%), 날도래목(Trichoptera, 1.7%), 잠자리목(Odonata, 0.4%)이었으며, 그 외 먹이생물은 환형동물문(Annelida)의 턱거머리목(Arhynchobdellida, 0.6%)과 실지렁이목(Tubificida, 0.1%), 선형동물문(Nematoda, 0.2%), 어류(Actinopterygii, 0.1%), 연체동물문(Mollusca)의 백합목(Veneroida) 등 다양하였다. 계절별로 보면, 봄에는 파리목(55.4%)과 하루살이목(41.6%)을, 여름에는 파리목(92.7%)과 환형동물문(Annelida, 6.8%)을, 가을에는 파리목(70.8%)과 하루살이목(9.0%), 날도래목(8.1%), 환형동물문(7.7%)을 주로 섭식하였다. 연령별로 보면 당년생 치어(0+)는 비교적 먹이 크기가 작은 파리목(주로 깔따구과(Chironomidae), 98.2%)만 거의 섭식한 반면, 성장하면서 파리목의 비율이 점점 감소하고 비교적 크기가 큰 하루살이목과 환형동물문의 비율이 증가하였다. 먹이 생물 크기는 당년생 치어(0+) 2.5±1.05 mm, 1년생(1+) 3.2±1.29 mm, 2년생(2+) 3.7±2.05 mm, 3년생 이상(≥3+) 6.8±4.97 mm로 성장하면서 급격히 커지는 경향을 보였다.

• Applied Microscopy
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• 제10권1_2호
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• pp.27-32
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• 1980

중동지방에 다녀온 48세의 한국인 남자 피부에 발생한 leishmania증 1예에 대하여 광학 및 전자현미경적 관찰을 하여 문헌 고찰과 아울러 보고하였다. 광학현미경적으로는 조직구 침윤을 주로 하는 만성 육아종성염증반응을 보였고 Giemsa염색상 다수의 leishmania충체를 조직구내에서 관찰할 수 있었다. 전자현미경적으로는 난원형의 단세포 또는 분열중인 충체가 조직구내에 존재하였고 충체는 이중막으로 싸였으며 그 바로밑에 microtubule이 배열되고 세포질내에는 신장된 mitochondrion내에 kinetoplast가 존재하고 그 전방에 flagella가 위치하였으며 기타 다수의 ribosome과 드물게 Golgi complex등을 관찰할 수 있었다. 이와같은 특징은 Leishmania tropica의 promastigote stage와 일치하였다. Leishmania증은 원칙적으로 열대병이나 열대지방과의 접촉이 빈번함에 따라 앞으로 우리나라에서도 보다 많은 증예가 발생할 것으로 사료된다.

• 환경생물
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• 제40권4호
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• pp.374-386
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• 2022

Phytoplankton communities, with emphasis on picoplankton and nanoplankton, were investigated in Gamak Bay, South Korea, where freshwater input and coastal water intrusion shape ecosystem functions. Shellfish farms and fish farms are located in the inner bay and outer bay, respectively, and tides translocate uneaten food and urine production from aquaculture farms toward the inner bay. Water masses were distinctly different based on a significantly different density between the surface and bottom layer and among three water masses, including the inner bay, outer bay, and Yeosu Harbor. Phytoplankton communities were quantified using flow cytometry and size-fractionated chlorophyll-a (chl-a) was measured. Salinity was a principal variable separating phytoplankton communities between the surface and bottom layer, whereas Si(OH)₄ controlled the communities in the inner bay, and NH₄⁺ and PO₄^3- governed the outer bay communities. While phycocyanin-containing (PC) cyanobacteria dominated in the outer bay, phycoerythrin-containing (PE) cyanobacteria dominance occurred with cryptophyte dominance, indicating that nutrients affected the distribution of pico- and nanoplankton and that cryptophytes potentially relied on a mixotrophic mode by feeding on PE cyanobacteria. Interestingly, picoeukaryotes and eukaryotes larger than 10 ㎛ were mostly responsible for the ecological niche in the western region of the bay. Given that chl-a levels have historically declined, our study highlights the potential importance of increased small phytoplankton in Gamak Bay. Particularly, we urge an examination of the ecological role of small phytoplankton in the food supply of cultivated marine organisms.

• 한국어류학회지
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• 제9권2호
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• pp.221-227
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• 1997

1994년 1월부터 1994년 12월까지 광양만 대도주변 잘피밭에서 채집된 주둥치의 식성을 조사하였다. 주둥치는 주로 요각류와 게의 유생을 먹었으며, 그 외 갯지렁이류, 단각류, 곤쟁이류, 새우류 등을 소량씩 먹었다 주둥치가 성장함에 따라 먹이생물의 조성 및 크기가 점차 변하였다. 체장이 작은 크기에서는 요각류를 상당히 많이 먹었으나, 체장이 증가하면서 위내용물 중 요각류가 차지하는 비율이 점차 낮아진 반면, 갯지렁이류의 비율은 점차 증가하였다. 한편, 게의 유생은 전 크기군에 걸쳐 지속적으로 많이 섭이되었다. 대체적으로 계절에 관계없이 게 유생의 섭이 비율은 거의 일정하였으나, 요각류와 갯지렁이류의 비율은 뚜렷한 계절 변동을 보였는데, 이는 출현하는 주둥치의 크기 조성이 계절에 따라 달라졌기 때문이다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 추계학술대회
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• pp.730-733
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• 2010

본 논문은 녹색조명설비의 구현으로 얇은 패널구조의 LED 조명등을 제작하여 가로등조명, 수중배양 양식조명, 집어등 및 수중탐사의 특수조명 활용성을 확인하였다. 제작된 패널구조의 녹색조명등은 상기한 용도의 조명등으로서 매우 탁월함이 확인되었다. 그 중 집어등의 경우는, 작은 치어 등의 미세생물체와 어류의 조광이동성 및 군집 활동성 증진에 효과적이었으며, 수중배양 양식 조명에서는 녹색 조류, 해초, 수초 및 각종 유기체의 광합성 성장에 유용하였고, 특히 수중조명장치로서의 방수성 및 방열작용의 탁월성이 확인되었다.

• 한국수산과학회지
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• 제51권3호
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• pp.305-312
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• 2018

This study was carried out to investigate euphausiid abundance in an acoustic survey from March 2010 to July 2010 to suggest reasonable usage and management of the euphausiid Euphausia pacifica in the coastal area of Guryongpo Pohang. The acoustic data were analyzed by the 2-frequency difference method and the distorted wave born approximation acoustical theoretical model, which is used for organisms of weak target strength with small scatter, such as euphausiid scatter, among other marine organisms. The distribution and monthly density of euphausiids were estimated in the survey area. The results show that the volume back scattering strength frequency difference for euphausiid was 13.91-7.6 dB, and their monthly averag density was $28.2g/m^2$.

• Fisheries and Aquatic Sciences
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• 제8권4호
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• pp.201-206
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• 2005

Microalgae are widely used for mass culture of the rotifer Brachionus plicatilis in aquaculture. Since the nutritional value of the rotifer is closely related to its food, the nutritional value of its food should be known in detail. Chlorella ellipsoidea and Nannochloris oculata are re­presentative food organisms for rotifers that are easily cultured. Therefore, the nutritional values of these micro algae were examined for ultrasmall, small, and large rotifers and Artemia nauplii. Chlorella ellipsoidea contained seven times more total fatty acids than N. oculata. The three types of rotifer fed N. oculata contained more amino acids than those fed C. ellipsoidea. However, the total fatty acids of the rotifers fed each microalga species differed according to the type of rotifer. Newly hatched Artemia nauplii contained more protein and had a higher dry weight than those fed microalgae for 6 h. As with the rotifers, the Artemia nauplii fed N. oculata contained more protein and amino acids than those fed C. ellipsoidea, while the reverse was true for the total fatty acid content. Our results suggest that N. oculata is a good supply of protein, while C. ellipsoidea is a good source of lipids as food organisms for rotifers and Artemia nauplii in aquaculture.