• The Plant Pathology Journal
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• 제15권2호
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• pp.127-130
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• 1999

Cytological changes of cowpea root at the early stage of root nodule formation (within 5 days after inoculation) were viewed by light and electron microscopy. The root region affected by the rhizobial infection, which was composed of a redial array of cortical cells, had prominent cell divisions, mostly anticlinal in the inner cortical cells and in addition oblique and periclinal in the outer cells. An infected root hair cell (or root hair-producing epidermal cell) had numerous infection threads and degenerated cytoplasm. Module meristem was formed adjacent to the infected root hair cell, and characterized by dense cytoplasm, prominent nucleus, numerous small vacuoles, and increased plastids, containing infection threads as well. Bacterial cells were dividing inside the infection thread, the wall materials of which appeared to be dissolved ad accumulated in small vacuoles. inner cortical cells contiguous to the nodule meristem appeared to be actively dividing and dedifferentiating; however, they were not infected by the rhizobia. These structural characteristics are similar to those in the Bradyrhizobium-soybean association previously reported, and may reflect the similar cytological process in cowpea in the early nodule formation.

• 식물조직배양학회지
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• 제27권3호
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• pp.233-238
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• 2000

야생 흰제비꽃의 엽병 유래 callus를 장기 계대배양하는 과정 중에 발생하는 순화된 friable callus와 분화능이 높은 compact callus를 비교 관찰한 바, friable callus는 연초록색으로 부서지기 쉬운 부드러운 callus이고, compact callus는 진녹색으로 단단한 callus였다. 동결처리 한 시료를 주사전자 현미경에서 동일하게 200배로 관찰하여 보면, friable callus 는 작은 세포집단으로 이루어진 세포군의 주변부에 고도로 액포화된 세포가 광범위하게 분포되어 있는 반면, compact callus는 거의 균일한 세포들로 구성되어 세포구성이 치밀한 것으로 관찰되었다. 또한 friable callus와 compact callus로 부터의 체세포배형성은 배양세포에서 배가 발생하여 배양기간이 지남에 따라 식물체로 분화하였다. 이와 같은 과정은 배양세포의 세포질이 보다 충만한 부위에서 배유사체 (embryo like body)의 발생이 이루어지는 것으로 관찰되었다.

• Journal of Microbiology
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• 제45권2호
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• pp.171-174
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• 2007

The growth stimulation of wild plants by several bacterial species showing plant growth-promoting capabilities was examined in a barren lakeside area at Lake Paro, Korea. Microbial numbers and activities in the field soil were monitored for 73 days after inoculation of the bacteria. The acridine orange direct counts for the total soil bacterial populations ranged between $2.0-2.3{\times}10^{9}\;cells/g$ soil and $1.4-1.8{\times}10^{9}\;cells/g$ soil in the inoculated and uninoculated soils, respectively. The numbers of Pseudomonas spp., which is known as a typical plant growth-promoting rhizobacteria, and the total microbial activity were higher in the inoculated soil compared to those in the uninoculated soil. The average shoot and root lengths of the wild plants grown in the inoculated soil were 17.3 cm and 12.4 cm, respectively, and longer than those of 11.4 cm and 8.5 cm in the uninoculated soil. The total dry weight of the harvested wild plants was also higher in the inoculated soil (42.0 g) compared to the uninoculated soil (35.1 g). The plant growth-promoting capabilities of the inoculated bacteria may be used for the rapid revegetation of barren or disturbed land, and as biofertilizer in agriculture.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.100.2-101
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• 2003

The global regulator, GacS (global antibiotic and cyanide sensor kinase), was required for the increased resistance to hydrogen peroxide occurring as cultures of the rhizobacterium, P. chlororaphis O6, matured. Specific stationary-phase peroxidase and catalase isozymes were absent in the GacS mutant, whereas a manganese-superoxide dismutase isozyme was expressed earlier and to a great extent than wild type. In the wild type cell, transcript accumulation of rpoS was higher in late logarithmic-phase cells than cells from mid logarithmic- or stationary-phase. Transcripts from rpoS in the GacS mutant were reduced in each of these growth phases compared to the wild type expression. The down stream sequence from rpoS lacked sequences encoding a small RNA, rsmZ, found in other pseudomonads and implicated in control of genes activated by the GacS system. These findings suggest that GacS-mediated regulation of RpoS plays role in control of oxidative stress in P. chlororaphis O6 by as yet an unknown mechanism.

• 식물조직배양학회지
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• 제27권5호
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• pp.375-377
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• 2000

It is now generally accepted that a phosphoinositide cycle is involved in the transduction of a variety of signals in plant cells. In animal cells, the hydrolysis of phosphatidyl-4,5-bisphosphate catalysed by phosphatidylinositol - specific phospholipase C yields to D-myo-inositol - 1,4,5-trisphosphate and diacylglycerol, which are well known second messengers. The binding of InsP$_3$to a receptor located on the endoplasmic reticulum triggers a calcium release from the endoplasmic reticulum. We have detected and partially characterised key components of phosphoinositide signaling. First, tobacco microsomal fraction and plasma membrane PI-PLC. Consecutively, using a radioligand binding assay we have identified a $Ca^{2+}$ -dependent high affinity InsP$_3$binding site in microsomal membrane fraction vesicle preparation and then we have measured inositol-1,4,5-trisphosphate induced calcium release from tobacco microsomal fraction. These findings suggest that phosphoinositide signaling system is present and operates in the tobacco suspension culture.e.

• 한국연초학회지
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• 제27권2호
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• pp.153-162
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• 2005

Tobacco (Nicotiana tabacum L.) cells were transformed with rice expansin genes, OsEXPA4, OsEXPB3, OsEXPB4, and OsEXPB6, to elucidate the function of the genes in tobacco cells. The transformation increased the mass of the callus by $36\%-65 \%$, and the cell length by $12\%-28\%$. The cell width was decreased by $3\%$ for OsEXPB3, not changed for OsEXPB4, increased by $25\%\;and\;20\%$ for OsEXPA4 and OsEXPB6, respectively. From database search, seven expansin genes were found and six of them belong to EXPA group and one of them belongs to EXPB group. EXLA and EXLB were not found. All tobacco expansin genes were evenly distributed in the phylogenetic tree of rice and Arabidopsis expansin genes.

• 한국초지조사료학회지
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• 제20권1호
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• pp.7-12
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• 2000

오차드그래스의 종자배양에서 형성된 캘러스를 현탁배양하여 배양기간별 부정배 형성정도와 식물체 재분화율 등에 대한 몇 가지 실험을 수행하여 얻은 결과를 요약하면 다음과 같다. 종자유래의 캘러스를 현탁배양하였을 때, 세포 모양이 둥근것과 그들의 세포괴는 배양 50일 후에 최대치를 나타내었고 그 이후는 감소하였다. 현탁배양 기간에 따른 갤러스의 부정배 형성과 식물체 분화율은 배양 60일째 가장 높았으며, 그 이후는 감소하는 경향이었다. 현탁배양에서 배지 내에 첨가되는 casein hydrolysate (CH)의 적정농도는 $4\;g/{\ell}$인 것으로 나타났다.

• Molecules and Cells
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• 제44권10호
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• pp.746-757
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• 2021

Plant somatic cells can be reprogrammed into a pluripotent cell mass, called callus, which can be subsequently used for de novo shoot regeneration through a two-step in vitro tissue culture method. MET1-dependent CG methylation has been implicated in plant regeneration in Arabidopsis, because the met1-3 mutant exhibits increased shoot regeneration compared with the wild-type. To understand the role of MET1 in de novo shoot regeneration, we compared the genome-wide DNA methylomes and transcriptomes of wildtype and met1-3 callus and leaf. The CG methylation patterns were largely unchanged during leaf-to-callus transition, suggesting that the altered regeneration phenotype of met1-3 was caused by the constitutively hypomethylated genes, independent of the tissue type. In particular, MET1-dependent CG methylation was observed at the blue light receptor genes, CRYPTOCHROME 1 (CRY1) and CRY2, which reduced their expression. Coexpression network analysis revealed that the CRY1 gene was closely linked to cytokinin signaling genes. Consistently, functional enrichment analysis of differentially expressed genes in met1-3 showed that gene ontology terms related to light and hormone signaling were overrepresented. Overall, our findings indicate that MET1-dependent repression of light and cytokinin signaling influences plant regeneration capacity and shoot identity establishment.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2019년도 춘계학술대회
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• pp.117-117
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• 2019

Kirengeshoma koreana Nakai (K. koreana)was Saxifragaceae and rare plants in Korea, which is classified as an Critically Endangered (CR) species in Korea. Therefore, most of the studies on it were ecological and taxonomic, and there are no studies on biological activity. In this study, we evaluated the whitening activity of K. koreana extract (KKE). Melanogenesis Inhibitory effects were demonstrated by western-bot and RT-PCR for the effects of KKE on MITF, tyrosinase, TRP-1 and TRP-2 in IBMX-treated B16F10 melanoma cells. IBMX were reported as melanin synthesis enhancers. It could increase intracellular melanin synthesis by activation of the microphthalmia-associated transcription factor (MITF) signaling pathway. KKE showed no cytotoxicity at B16F10. In addition, KKE effectively inhibited the protein and mRNA levels of MITF, tyrosinase, TRP-1 and TRP-2. In conclusion, KKE inhibited melanin synthesis by inhibiting the expression of MITF and its downstream pathways tyrosinase, TRP-1 and TRP-2. Therefore, it was confirmed that K. koreana is a valuable resource for functional cosmetic and biomaterials.

• 대한수의학회지
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• 제60권4호
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• pp.195-202
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• 2020

Feline calicivirus (FCV) infection results in a common upper respiratory disease associated with oral ulceration in cats. Although FCV infection has been reported in cats worldwide, the biologic and genetic features of South Korean FCV are unclear. We aimed to investigate the biological and genetic features of South Korean FCV isolates. Crandell-Rees feline kidney (CRFK) cells were used to isolate FCV from 58 organ homogenate samples. The FCV isolates were confirmed by cytopathic effects, immunofluorescence, electron microscopy, and reverse transcription polymerase chain reaction assays. Viral genetic analysis was carried out with VP2 gene and complete genomes of FCVs. Five viruses propagated in CRFK cells were confirmed to be FCVs. The FCV17D283 isolate showed the highest viral titer of 107.2 TCID50/mL at 36 h post-inoculation. Korean FCV isolates did not grow well in Vero, BHK-21, A72, or Madin-Darby canine kidney cells. The FCV17D03 and FCV17D283 isolates had the highest genetic similarity (80.1% and 86.9%) with the UTCVM-H1 and 14Q315 strains, which were isolated in the United States and South Korea in 1995 and 2014, respectively. We isolated five FCVs from cats and detected important genetic differences among them. FCV isolates did not show any virulent effects in mice.