• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.10a
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• pp.9-18
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• 2003

A method for rapid propagation of mature Jack fruit was developed. Four types of explants (mature embryos, apical meristems of young seedlings, apices from mature plants and nodal segments) were used. It has been found 88% of young apical meristems produced shoots in Campbell and Durzan (CD) medium compared to 60% in Murashige and Skoog (MS) medium. Only 1/3 of them produced multiple shoots. Shoot idtiation from nodal segments was very rare. Mature apices produced callus. Although removed of the sheathing cover around mature buds enhanced the shoot initiation but success rate was low in growth regulator free medium. Embryos respond to the CD medium but not to the MS medium. Embryos from seeds soaked in water for 24 hours produced shoots after 8 weeks of incubation and the success rate was 70% while embryos from dry seeds only produced roots. There was no significant effect of cold storage (refrigeration) for 7 days on shoot initiation from mature embryos (65%) but the ability for shoot induction declines with storage time (55% after 21 days of cold storage). Mature axillary buds were established in Modified Campbell and Durzan (CD) medium supplemented with 0.5mg/1 and IBA. There was a significant difference in the growth performance of shoots according to the period of the year in which explants were collected. Highest (60%) was observed in November-January period. It was only 30% when the explants were collected in February-April or May-July and decreased to 20% in August-October. The shoots produced in November-January showed a higher vigor than those produced in other months. Since Jak fruit show seasonal changes in fruit bearing and shedding of leaves, it can be suggested that the difference in growth performances of tissues cultured in artificial culture media would have been affected by endogenous rhythms.

• Molecules and Cells
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• v.41 no.12
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• pp.1072-1080
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• 2018

A plant-specific B3 domain and AP2 domain-containing transcription factor, RAV1 acts as a negative regulator of growth in many plant species and its transcription was down-regulated by BR and ABA. In this study, we found that RAV1-overexpressing transgenic plants showed abnormally developed ovules, resulting in reduced seed size, weight, and number in a silique. Interestingly, the endogenous expression of RAV1 fluctuated during seed development; it remained low during the early stage of seed development and sharply increased in the seed maturation stage. In plants, seed development is a complex process that requires coordinated growth of the embryo, endosperm, and maternal integuments. Among many genes that are associated with endosperm proliferation and embryo development, three genes consisting of SHB1, MINI3, and IKU2 form a small unit positively regulating this process, and their expression was regulated by BR and ABA. Using the floral stage-specific RNAs, we found that the expression of MINI3 and IKU2, the two downstream genes of the SHB1-MINI3-IKU2 cascade in the seed development pathway, were particularly reduced in the RAV1-overexpressing transgenic plants. We further determined that RAV1 directly binds to the promoter of MINI3 and IKU2, resulting in their repression. Direct treatment with brassinolide (BL) improved seed development of RAV1-overexpressing plants, but treatment with ABA severely worsened it. Overall, these results suggest that RAV1 is an additional negative player in the early stages of seed development, during which ABA and BR signaling are coordinated.

• Korean Journal of Pharmacognosy
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• v.51 no.4
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• pp.302-309
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• 2020

The objective of this study was to optimize the condition for induction and proliferation of callus from Rhus chinensis Mill. and investigate the skin-brightening effect of Rhus chinensis callus (RCC). It was confirmed that the most proper plant growth regulator (PGR) for callus induction is 1.0 mg/L of 2,4-dichlorophenoxyacetic acid (2,4-D). The most optimal condition of PGR, medium and additives for callus proliferation were 2,4-D (1.0 mg/L), MS medium and citric acid, respectively. Inhibitory activities of tyrosinase were higher at 50 and 100 ㎍/mL of RCC extracts (41.86 and 75.56%, respectively) than arbutin (27.32%). As the results of measuring melanin inhibition in B16F1 melanocyte and B16F10 melanoma cell, RCC extracts increased its inhibitory activities concentration-dependently, and were found to have higher whitening effect than arbutin at a concentration of 100 ㎍/mL. Therefore, it is suggested that RCC can be used as an effective material for skin-brightening cosmetics.

• Molecules and Cells
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• v.45 no.10
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• pp.695-701
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• 2022

Homeostatic regulation of meristematic stem cells accomplished by maintaining a balance between stem cell self-renewal and differentiation is critical for proper plant growth and development. The quiescent center (QC) regulates root apical meristem homeostasis by maintaining stem cell fate during plant root development. Cell cycle checkpoints, such as anaphase promoting complex/cyclosome/cell cycle switch 52 A2 (APC/C^CCS52A2), strictly control the low proliferation rate of QC cells. Although APC/C^CCS52A2 plays a critical role in maintaining QC cell division, the molecular mechanism that regulates its activity remains largely unknown. Here, we identified SCF^FBS1, a ubiquitin E3 ligase, as a key regulator of QC cell division through the direct proteolysis of CCS52A2. FBS1 activity is positively associated with QC cell division and CCS52A2 proteolysis. FBS1 overexpression or ccs52a2-1 knockout consistently resulted in abnormal root development, characterized by root growth inhibition and low mitotic activity in the meristematic zone. Loss-of-function mutation of FBS1, on the other hand, resulted in low QC cell division, extremely low WOX5 expression, and rapid root growth. The 26S proteasome-mediated degradation of CCS52A2 was facilitated by its direct interaction with FBS1. The FBS1 genetically interacted with APC/C^CCS52A2-ERF115-PSKR1 signaling module for QC division. Thus, our findings establish SCF^FBS1-mediated CCS52A2 proteolysis as the molecular mechanism for controlling QC cell division in plants.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.58-58
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• 2021

Although hypoxic/ischemic injury is thought to contribute to the incidence of Alzheimer disease (AD), the molecular mechanism that determines the relationship between hypoxia-induced β-amyloid (Aβ) generation and development of AD is not yet known. In this study, we investigated the protective effects of Acorus gramineus Soland. (AGS) on oxygen-glucose deprivation/reoxygenation (OGD/R)-induced A β production in SH-SY5Y human neuroblastoma cells. Pretreatment of these cells with AGS significantly attenuated OGD/R-induced production of reactive oxygen species (ROS) and elevation of levels of malondialdehyde, nitrite (NO), prostaglandin E2 (PGE2), cytokines (TNF-α, IL-1β and IL-6) and glutathione, as well as superoxide dismutase activity. AGS also reduced OGD/R-induced expression of the apoptotic protein caspase-3, the apoptosis regulator Bcl-2, and the autophagy protein becn-1. Finally, AGS reduced OGD/R-induced Aβ production and cleavage of amyloid precursor protein, by inhibiting secretase activity and suppressing the autophagic pathway. Although supporting data from in vivo studies are required, our results indicate that AGS may prevent neuronal cell damage from OGD/R-induced toxicity.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.1
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• pp.14-25
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• 2012

Recently, the application and installation of the pod propeller to the cruise ship is dramatically increased. It is because pod propulsion system allows a lot of flexibility in design of the internal arrangement of a ship. To reflect this trend, many researches have conducted to use the pod propeller for the roll stabilization of a ship. In the paper, a roll stabilization controller is designed by using fins and pod propellers as the control actuators for cruise ships. Two kinds of control algorithms are adopted for the roll control system; LQR (Linear Quadratic Regulator) algorithm and frequency-weighted LQR algorithm. Through the numerical simulation, the effect of the turning rate of the pod propeller on the roll control system is analyzed. Analysis of the simulation results indicated that the turning rate of the pod propellers is one of the important parameters which give the significant effects on the roll stabilization.

• Asian Journal of Turfgrass Science
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• v.14 no.1
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• pp.273-280
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• 2000

This study was conducted to evaluate an efficiency of plant growth regulator trinexapacethy(Primo) on the growth response of bentgrass and the change to soil water content in bentgrass green. Based on the results of the study, the following results were observed. 1. During four weeks after treatment, the visual color and turfgrass density of all the treated plots with trinexapac-ethyl(Primo) were more improved rather than without. Two treatments trinexapac-ethyl /$0.02mL\m^2$ and $0.04mL/\m^2$ were more favorable than other treatments. 2. It suggested that optimum rate to reduce the bentgrass growth and to increase the turfgrass density was the trinexapac-ethyl $0.04mL/\m^2$. 3. For six weeks after treatment, all treated plots were not significantly different (P<0.05) in turfgrass root length and root dry weitht. 4. In the treated plots with trinexapac-ethyl $0.04mL/\m^2$ for 25days in bentgrass green, soil water consumption was approximately 35% to 40% compare to the non-treated control.

• BMB Reports
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• v.42 no.7
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• pp.439-443
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• 2009

Dehydrins are group II, late embryogenesis abundant proteins that act putatively as chaperones in stressed plants. To elucidate the function of dehydrins in poplar, we isolated the $SK_2$-type dehydrin gene Podhn from Populus alba $\times$ P. tremula var. glandulosa suspension cells and analyzed its expression following treatments of abiotic stress, wounding and plant growth regulator. Sequence homology and phylogenetic analyses indicate Podhn encodes an acidic dehydrin (pI 5.14, 277 amino acids, predicted size 25.6 kDa) containing two lysine-rich "K-segments" and a 7-serine residue "S-segment", both characteristic of $SK_2$-type dehydrins. Southern blots show Podhn genes form a small gene family in poplar. Podhn was expressed in all tissues examined under unstressed conditions, but most strongly in cell suspensions (especially in the stationary phase). Drought, salt, cold and exogenous abscisic acid (ABA) treatments enhanced Podhn expression, while wounding and jasmonic acid caused its reduction. Therefore, Podhn might be involved in ABA or stress response.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.23
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• pp.10483-10487
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• 2015

Heptaphylline derivatives are carbazoles in Clausena harmandiana, a medicinal plant that is utilized for headache, stomach ache, and other treatments of illness. The present study examined the effects of heptaphylline and 7-methoxyheptaphylline on apoptosis of human colon adenocarcinoma cells (HT-29 cell line). Quantification of cell viability was performed using cell proliferation assay (MTT assay) and of protein expression through immunoblotting. The results showed that only heptaphylline, but not 7-methoxyheptaphylline, significantly significantly activated cleaved of caspase-3 and poly (ADP-ribose) polymerase (PARP-1) which resulted in HT-29 cell death. We found that heptaphylline activated BH3 interacting-domain death agonist (Bid) and Bak, proapoptotic proteins. In contrast, it suppressed X-linked inhibitor-of-apoptosis protein (XIAP), Bcl-xL and survivin, inhibitors of apoptosis. In addition, heptaphylline inhibited activation of NF-${\kappa}B$/p65 (rel), a regulator of apoptotic regulating proteins by suppressing the activation of Akt and $IKK{\alpha}$, upstream regulators of p65. The findings suggested that heptaphylline induces apoptosis in human colon adenocarcinoma cells.

• Molecules and Cells
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• v.19 no.3
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• pp.342-349
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• 2005

Cytokinins are adenine derivatives that regulate numerous plant growth and developmental processes, including apical and floral meristem development, stem growth, leaf senescence, apical dominance, and stress tolerance. However, not much is known about how cytokinin biosynthesis and metabolism is regulated. We identified a novel Arabidopsis gene, ALL, encoding an aldolase-like enzyme that regulates cytokinin signaling. An Arabidopsis mutant, all-1D, in which ALL is activated by the nearby insertion of the 35S enhancer, exhibited extreme dwarfism with rolled, dark-green leaves and reduced apical dominance, symptomatic of cytokinin-overproducing mutants. Consistent with this, ARR4 and ARR5, two representative primary cytokinin-responsive genes, were significantly induced in all-1D. Whereas SHOOT MERISTEMLESS (STM) and KNAT1, which regulate meristem development, were also greatly induced, expression of REV and PHV that regulate lateral organ polarity was inhibited. ALL encodes an aldolase-like enzyme that belongs to the HpcH/HpaI aldolase family in prokaryotes and is down-regulated by exogenous cytokinin, possibly through a negative feedback pathway. We propose that ALL is involved in cytokinin biosynthesis or metabolism and acts as a positive regulator of cytokinin signaling during shoot apical meristem development and determination of lateral organ polarity.