• The Plant Pathology Journal
• /
• v.34 no.4
• /
• pp.269-285
• /
• 2018

Bacterial leaf blight is a major disease of eucalypt, especially under nursery conditions. Different bacterial species have been associated with the disease in several countries, and despite its importance worldwide, it is not clear to date whether similar disease symptoms are caused by the same or by different etiological agents. In this study, 43 bacterial strains were isolated from blighted eucalypt leaves collected in different geographic areas of Brazil and inoculated onto a susceptible eucalypt clone. Polyphasic taxonomy, including morphological, physiological, biochemical, molecular, and pathogenicity tests showed that only certain strains of Xanthomonas axonopodis caused symptoms of the disease. Strains varied in their aggressiveness, but no correlation with geographic origin was observed. MLSA-based phylogenetic analysis using concatenated dnaK, fyuA, gyrB and rpoD gene sequences allocated the strains in a well-defined clade, corresponding to Rademarker's group RG 9.6. Inoculation of nineteen plant species belonging to seven botanical families with representative strain LPF 602 showed it to be pathogenic only on Eucalyptus spp, and Corymbia spp. Based on distinct biochemical and pathogenic characteristics that differentiate the eucalypt strains from other pathovars of the X. axonopodis species, here we propose their allocation into the new pathovar X. axonopodis pv. eucalyptorum pv. nov.

• The Journal of Korean Society of Virology
• /
• v.29 no.4
• /
• pp.201-209
• /
• 1999

Results of the studies on the morphologic and molecular biologic characteristics of Hantaan virus (HTNV), one of the etiologic agents of Hemorrhagic fever with renal syndrome (HFRS), revealed that HTNV was a member of Family Bunyaviridae and its RNA divided into three segments. And the nucleotide sequences of these segments also were known and the differences in nucleotide sequences of HTNV from other members of genus Hantavirus were clearly evaluated. But the morphorgenesis, pathogenesis of HFRS and the replication time had not been clearly determined. In this study, to estimate the replication time of HTNV in Vero E-6 cells, Vero cells were infected with HTNV 76/118 strain, and cells were harvested from two hours post-infection up to 24 hours at two hours-intervals. Harvested cells were treated with ordinary techniques for electron microscopy and immune-electron microscopy. And then thin sections were observed under transmission electron microscope. HTNV particles were not found in the cytoplasm and in the extracellular space between $2{\sim}8$ hours after inoculation of virus, but virus particles were observed in extracellular space near the cell membrane of Vero-E6 cells 10 hours after infection. In immune electron microscopy, mature HTNV particles in extracellular spaces and immature virus labelled with gold particles in the cytoplasm of Vero E-6 cell 10 hours after infection of HTNV could be seen. This results suggest that the replication time of HTNV might be about 10 hours.

• The Journal of Korean Society of Virology
• /
• v.30 no.1
• /
• pp.19-28
• /
• 2000

Two distinct hantaviruses have been isolated from Apodemus agrarius in 1976 and Rattus norvegicus in 1980 in Korea. Since our serosurveys conducted in 1994, a genetically distinct hantavirus from Apodemus peninsulae has been investigated. To isolate hantavirus from Apen insulae captured in Korea, the lung homogenate of seropositive Apeninsulae inoculated Vero E6 cells. Viral antigen was detected in a progressively higher percentage of cells with subsequent passage after 80 days postinoculation. The new isolate from seropositive Apodemus peninsulae was designated Suchong virus after Suchong valley located in northeastern region of South Korea. Comparing with hantaan virus 76-118 strain, Suchong virus-1, 2, 3 and 4 showed the similarity of $71.0{\sim}91.8%$ at nucleotide and $90.9{\sim}94.8%$ at amino acid sequences in 231 nucleotides region of M segment, and the similarity of $75.1{\sim}81.0%$ at nucleotide and $97.5{\sim}100%$ at amino acid sequences in 237 nucleotides of S segment.

• Research in Plant Disease
• /
• v.17 no.1
• /
• pp.82-85
• /
• 2011

Bakanae disease symptom were observed in barnyard grass in paddy field in Heanam, Jeonnam. The infected plants were blighted and white mass of spore were formed on the stem. Fusarium species were isolated from infected stem and the isolates were identified as Fusarium fujikuroi based on their morphological and molecular characteristics. The isolates of F. fujikuroi were assigned to reference of F. fujikuroi among related Fusarium species based on the translation elongation factor 1-alpha gene sequence. Pathogenicity of the fungal isolates was confirmed on seedlings of rice and barnyard grass by artificial inoculation. The results indicated that barnyard grass can be inoculum source of Bakanae disease on rice. Thus, effective weed management is necessary to Bakanae disease control and healthy seed production.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1998.02a
• /
• pp.110-110
• /
• 1998

GaN는 직접천이형 에너지 캡을 가지며 In과 화합물을 형성할 경우 1.geV-3.4eV까지 다양한 에너지 캡을 가지므로 청색 발광소자 고출력소자 고온 전자소자둥 웅용성이 많 은 물절로서 각광을 받고 있다. 그러나 G랴‘에 적합한 기판이 없다는 문제점으로 인하여 F FET, LD와 같은 다양한 구조의 웅용에 제 약이 따랐다. 이에 본 연구에서는 RF(radio frequency) Plasma-Assisted MBE( molecular beam e epitaxy )를 이용하여 InxGaj xN/G암J 양자우물 구조를 성장하였다. 이렇게 성장된 I InxGaj xN 박막과 InxGaj xN/GaN 양자우물구조의 특성의 분석은 광학적 특성올 PL( p photoluminescence ) , 결 정 성 의 분석 은 XRD ( x-ray diffraction ), 표면 과 단변 의 계 변 특성은 SEM(scanning electron microscopy)을 이용하여 분석하였다. 저온 PL의 측정결 과 기판온도를 680$^{\circ}$C로 고정한 후 In cell의 온도를 650$^{\circ}$C에서 775$^{\circ}$C까지 증가함에 따라 I InxGaj xN에 관계된 피크위치가 약3이neV정도 red shift 함을 관찰할 수 있었다. 한편 I InxGaj xN/GaN 양자우물구조의 경우 PL피크가 3.2없eV로써 InxGaj- xN의 PL 피크에 비 해 에서 약 25me V 고에너지 이동이 관측되었으며 이것은 우불 내에서 에너지레벨의 c confinement효과에 의해 에너지의 변화에 의한 것엄올 확인하였으며, 양자우물 구조에서 우물의 두께를 줄임에 따라 변화 폭은 1이neV정도 고에너지 이동을 관찰할 수 있었다. X XRD 측정의 결과 In의 mole fraction에 따라 격자상수의 변화를 관찰하였으며, 결정 성의 변화를 피크의 세기로 관찰하였다 .. XRD로 판단한 In의 mole fraction은 0.2임을 알 았다 .. SEM 측정은 표변과 단면의 측정으로서 표연특성과 단면의 특성을 InxGaj xN, I InxGaj xN/GaN 양자우물 구조 모두 알아보았다. 측정 결과 InxGaj-xN의 성 장조건으로 기판온도가 낮아지면서 표면의 거칠기 정도가 증가하였으며,680$^{\circ}$C의 기판온도에서 성장 한 양자우물 구조에 있어서 매끄라운 표면올 얻올 수 있었다.

• Journal of Mushroom
• /
• v.18 no.1
• /
• pp.72-78
• /
• 2020

During the monitoring of fungal pests in 2016 and 2017, Acrodontium crateriforme, Naganishia friedmannii, Pestalotiopsis trachicarpicola, Penicillium wollemiicola, and Trichoderma thailandicum were isolated from indoor air, mushroom flies (Phytosciara flavipes), and media materials in the cultivation houses of oak wood mushroom (Lentinula edodes) located in Seocheon, Jangheung, Buyeo, and Yeoju, Korea. These fungal species were identified based on their morphological characteristics after their growth on PDA and subsequent molecular analyses of the 26S rDNA, 28S rDNA, β-tubulin gene, and translation elongation factor 1-α gene using PCR amplification and nucleotide sequencing were performed. The results showed that these fungi were previously undocumented in Korea. This study reports descriptions of their taxonomical and known properties.

• Applied Chemistry for Engineering
• /
• v.1 no.2
• /
• pp.140-146
• /
• 1990

Polydimethylsiloxane(PDMS) containing [N, N'-bis (3- (salicylidene amino) propyl) amine Co(II)] (Co(saldpt)) as a fixed oxygen carrier was synthesized. UV-visible spectra of the membrane demonstrated that Co(saldpt) binded molecular oxygen specificaaly and reversibly. From time lag method experiment, it was found that both oxygen permeability and diffusibity increase with decreasing upstream pressure, while solubility maintain nearly constant. The maximum oxygen permeability and oxygen selectivity over nitrogen obtained was 18.6 barrer and 4, respectively, at 25 mmHg and $40^{\circ}C$ from the the PDMS membrane containing 1 wt% of Co(saldpt). Facilitation behavior was explained in terms of the dual sorption model.

• Molecules and Cells
• /
• v.21 no.3
• /
• pp.343-355
• /
• 2006

Stem cells are unique cell populations with the ability to undergo both self-renewal and differentiation, although a wide variety of adult stem cells as well as embryonic stem cells have been identified and stem cell plasticity has recently been reported. To identify genes implicated in the control of the stem cell state as well as the characteristics of each stem cell line, we analyzed the expression profiles of genes in human embryonic, hematopoietic ($CD34^+$ and $CD133^+$), and mesenchymal stem cells using cDNA microarrays, and identified genes that were differentially expressed in specific stem cell populations. In particular we were able to identify potential hESC signature-like genes that encode transcription factors (TFAP2C and MYCN), an RNA binding protein (IMP-3), and a functionally uncharacterized protein (MAGEA4). The overlapping sets of 22 up-regulated and 141 down-regulated genes identified in this study of three human stem cell types may also provide insight into the developmental mechanisms common to all human stem cells. Furthermore, our comprehensive analyses of gene expression profiles in various adult stem cells may help to identify the genetic pathways involved in self-renewal as well as in multi-lineage specific differentiation.

• Molecules and Cells
• /
• v.39 no.10
• /
• pp.734-741
• /
• 2016

Granulocyte-macrophage colony stimulating factor (GM-CSF) has a role in inducing emergency hematopoiesis upon exposure to inflammatory stimuli. Although GM-CSF generated murine bone marrow derived cells have been widely used as macrophages or dendritic cells in research, the exact characteristics of each cell population have not yet been defined. Here we discriminated GM-CSF grown bone marrow derived macrophages (GM-BMMs) from dendritic cells (GM-BMDCs) in several criteria. After C57BL/6J mice bone marrow cell culture for 7 days with GM-CSF supplementation, two main populations were observed in the attached cells based on MHCII and F4/80 marker expressions. GM-BMMs had $MHCII^{low}F4/80^{high}$ as well as $CD11c^+CD11b^{high}CD80^-CD64^+MerTK^+$ phenotypes. In contrast, GM-BMDCs had $MHCII^{high}F4/80^{low}$ and $CD11c^{high}CD8{\alpha}^-CD11b^+CD80^+CD64^-MerTK^{low}$ phenotypes. Interestingly, the GM-BMM population increased but GM-BMDCs decreased in a GM-CSF dose-dependent manner. Functionally, GM-BMMs showed extremely high phagocytic abilities and produced higher IL-10 upon LPS stimulation. GM-BMDCs, however, could not phagocytose as well, but were efficient at producing $TNF{\alpha}$, $IL-1{\beta}$, IL-12p70 and IL-6 as well as inducing T cell proliferation. Finally, whole transcriptome analysis revealed that GM-BMMs and GM-BMDCs are overlap with in vivo resident macrophages and dendritic cells, respectively. Taken together, our study shows the heterogeneicity of GM-CSF derived cell populations, and specifically characterizes GM-CSF derived macrophages compared to dendritic cells.

• Molecules and Cells
• /
• v.40 no.10
• /
• pp.714-730
• /
• 2017

Pre-mRNA splicing further increases protein diversity acquired through evolution. The underlying driving forces for this phenomenon are unknown, especially in terms of gene expression. A rice alternatively spliced transcript detection microarray (ASDM) and RNA sequencing (RNA-Seq) were applied to differentiate the transcriptome of 4 representative organs of Oryza sativa L. cv. Ilmi: leaves, roots, 1-cm-stage panicles and young seeds at 21 days after pollination. Comparison of data obtained by microarray and RNA-Seq showed a bell-shaped distribution and a co-lineation for highly expressed genes. Transcripts were classified according to the degree of organ enrichment using a coefficient value (CV, the ratio of the standard deviation to the mean values): highly variable (CVI), variable (CVII), and constitutive (CVIII) groups. A higher index of the portion of loci with alternatively spliced transcripts in a group (IAST) value was observed for the constitutive group. Genes of the highly variable group showed the characteristics of the examined organs, and alternatively spliced transcripts tended to exhibit the same organ specificity or less organ preferences, with avoidance of 'organ distinctness'. In addition, within a locus, a tendency of higher expression was found for transcripts with a longer coding sequence (CDS), and a spliced intron was the most commonly found type of alternative splicing for an extended CDS. Thus, pre-mRNA splicing might have evolved to retain maximum functionality in terms of organ preference and multiplicity.