• Korean Journal of Plant Tissue Culture
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• v.26 no.3
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• pp.219-222
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• 1999

To induce adventitious buds, hypocotyl and cotyledonary explants from 7 to 10 day-old seedlings of lettuce (Lactuca sativa L.: two Japanese cultivars of crisphead lettuce and four Korean cultivars of leaf lettuce) were cultured or Murashige and Skoog (MS) and Schenk and Hildebrandt (SH) media supplemented with BA and NAA in the light for five weeks. Cotyledonary explants produced adventitious shoots at greater frequencies than hypocotyl explants. MS medium was more favorable to adventitious shoot formation than HS medium. Combination of 0.5 mg/L BA and 0.1 to 1 mg/L HPh in MS medium led to the greatest frequency (86%) in adventitious shoot formation. Creator than 95% of shoots excised from explants were rooted when cultured on MS basal medium.

• Plant Biotechnology Reports
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• v.3 no.4
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• pp.333-340
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• 2009

Developmental anomalies in the plumule meristem of peanut (Arachis hypogaea L.) somatic embryos resulted in poor shoot differentiation and reduced plant recovery. Existing meristems with caulogenic potential have never been tested for embryogenesis in peanut. The present experiment was designed to test the mature zygotic embryo axis derived plumule with three meristems for somatic embryogenesis. Embryogenic masses and embryos developed from the caulogenic meristems in the axils. Exposure of 2 weeks in primary medium with $90.5{\mu}M$ 2,4-D suppressed the shoot tip differentiation temporarily which then regained the ability to form the shoot on withdrawal of 2,4-D. Exposure of 4 weeks in primary medium with $90.5{\mu}M$ 2,4-D suppressed the shoot tip differentiation irreversibly. No shoot formation was noted from the tips in any of the cultures which were in secondary medium with $13.6{\mu}M$ 2,4-D. Development of somatic embryos directly from axillary meristems was confirmed histologically. Conversion frequency of these embryos was 11%. Thus, in this report, we describe a method to obtain somatic embryos from the determined organogenic buds of the axillary meristem, by culturing the nodal explant vertically on embryo induction medium. It also displays the possibility of obtaining both embryogenic and organogenic potential in two parts of the same explant simultaneously. The possibility of extending this approach for genetic transformation in in vivo system through direct DNA delivery or Agrobacterium injection in meristems can also be explored. Using Agrobacterium rhizogenes, we have demonstrated the possibility of gene transfer in the axillary meristems of seed-derived plumule explant.

• Korean Journal of Clinical Laboratory Science
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• v.41 no.4
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• pp.180-188
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• 2009

Plakoglobin (PKG) is a protein linking cadherin adhesion receptors to the actin cytoskeleton and its overexpression has been known to suppress cell proliferation and tumorigenesis in thyroid cancer. We investigated the effect of 5-aza-2'-deoxycytidine (5-Aza-CdR), a DNA methyltransferase inhibitor, on the methylation status of the promoter and the expression of the plakoglobin gene in a thyroid carcinoma cell line (ARO) and papillary thyroid carceinoma. In cultures of ARO cell line incubated without 5-Aza-2'-deoxycytidine (5-Aza-CdR), five of the fifteen CpG sites in the promoter spanning -225 and -54 were methylated at 4.2 - 12.5%. When the cells were treated with 5-Aza-CdR, all the methylated CpG sites were induced to be demethylated except one. In addition, a new methylation at one CpG site, CpG4, was identified at level of 12.0%. The expression level of PKG decreased approximately 10-fold in the 5-Aza-CdR treated cells compared to untreated cells. Different pattern of promoter methylation and expression of PKG was also observed in the tissue samples. CpG10 and CpG12 sites were methylated at 9.0-27.0% in normal tissues. However, in cancer tissues, CpG5 and CpG10 sites were methylated at 10.0-22.0%. Three of ten normal thyroid tissue samples and one of thirteen papillary carcinoma tumor samples showed increased PKG mRNA expression level. PKG protein expression analyzed by the immunohistochemical staining showed higher expression in the tumor compared with normal.

• Korean Journal of Plant Tissue Culture
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• v.21 no.5
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• pp.281-286
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• 1994

The hormonal regulation of organ differentiation was investigated in the tissue culture of sweet potato. Embryogenic callus was induced from shoot tips cultured on MS medium supplemented with 1 mg/L 2,4-D. When embryogenic callus was transferred to medium containing 0.1 mg/L GA$_4$, it proliferation was stimulated. The callus gave rise to plantlets when cultured on medium containing 0.1 mg/L BA. Addition of 0.1 mg/L jasmonic acid or 0.01 mg/L brassinolide to medium was effective for the development of healthy normal plantlets.

• Journal of Microbiology and Biotechnology
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• v.29 no.7
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• pp.1096-1103
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• 2019

UCB-1 is the commercial rootstock of pistachio. Reproduction of this rootstock by tissue culture is limited by low levels of proliferation rate. Therefore, any compound that improves the proliferation rate and the quality of the shoots can be used in the process of commercial reproduction of this rootstock. Use of plant growth-promoting bacteria is one of the best ideas. Given the beneficial effects of nanoparticles in enhancement of the growth in plant tissue cultures, the aim of the present study was to investigate the effects of nanoencapsulation of plant growth-promoting rhizobacteria (using silica nanoparticles and carbon nanotubes) and their metabolites in improving UCB1 pistachio micropropagation. The experiment was conducted in a completely randomized design with three replications. Before planting, treatments on the DKW medium were added. The results showed that the use of Pseudomonas fluorescens VUPF5 and Bacillus subtilis VRU1 nanocapsules significantly enhanced the root length and proliferation. The nanoformulation of the VUPF5 metabolite led to the highest root length (6.26 cm) and the largest shoot (3.34 cm). Inoculation of explants with the formulation of the metabolites (both bacterial strains) significantly elevated the average shoot length and the fresh weight of plant compared to the control. The explants were dried completely using both bacterial strains directly and with capsule coating after the three days.

• Tissue Engineering and Regenerative Medicine
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• v.15 no.6
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• pp.793-801
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• 2018

BACKGROUND: The aim of this study was to evaluate the combined effect of low-level laser treatment (LLLT) and recombinant human bone morphological protein-2 (rhBMP-2) applied to hypoxic-cultured MC3T3-E1 osteoblastic cells and to determine possible signaling pathways underlying differentiation and mineralization of osteoblasts under hypoxia. METHODS: MC3T3-E1 cells were cultured under 1% oxygen tension for 72 h. Cell cultures were divided into four groups: normoxia control, low-level laser (LLL) alone, rhBMP-2 combined with LLLT, and rhBMP-2 under hypoxia. Laser irradiation was applied at 0, 24, and 48 h. Cells were treated with rhBMP-2 at 50 ng/mL. Alkaline phosphatase activity was measured at 3, 7, and 14 days to evaluate osteoblastic differentiation. Cell mineralization was determined with Alizarin red S staining at 7 and 14 days. Western blot assays were performed to evaluate whether p38/protein kinase D (PKD) signaling was involved. RESULTS: The results indicate that LLLT and rhBMP-2 synergistically increased alkaline phosphatase (ALP) activity and mineralization. Western blot analyses showed that expression of type I collagen, runt-related transcription factor 2 (RUNX2), and Osterix (Osx), increased and expression of hypoxia-inducible factor 1-alpha ($HIF-1{\alpha}$), decreased more in the LLLT and rhBMP-2 combined group than in the rhBMP-2 or LLL alone groups. Moreover, LLLT and rhBMP-2 stimulated p38 phosphorylation and rhBMP-2 and LLLT increased Prkd1 phosphorylation. CONCLUSION: Combined treatment with rhBMP-2 and LLL induced differentiation and mineralization of hypoxic-cultured MC3T3-E1 osteoblasts by activating p38/PKD signaling in vitro.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.2
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• pp.99-105
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• 2000

Cell-Cell interaction and the extracellular matrix (ECM) are belisved to play essential roles during in vitro culturing of primary hepatocytes in the control of differentiation and in the maintenance of tissue spcific functions. The objective of this study was to examine the effects of degree of cell-cell contact (DCC) on liver sperific function of rat promary hepatocytes. Hepatocyte aggregates with various with various degrees of cell-cell contantact, I. e., dispersed cell, longish aggregate, rugged aggregate, and smooth spheroid were obtained at 1, 5-6, 15-20, and 36-48 hrs, respectively in suspension cultures grown in spinner flasks embedded in Caalginate bead and collagen gel in order. The may result from mass transfer limitation and shear damage caused by agitation during aggregation. The rugged aggregate showed a higer viability and albumin secretion rate than the dispersed cells or the other aggregates. This result indicates the possible enhancement of a bioartificial liver's (BAL) performance using primary hepatocytes and the reduction in time to prepare a BAL through optimization of the immobilization time.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.9
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• pp.1315-1328
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• 2004

Conjugated linoleic acid (CLA) is a mixture of positional and geometric isomers of octadecadienoic acid with two conjugated double bonds. Of more than a dozen isomers of CLA found naturally in dairy and meat products from ruminants, c-9, t-11 and t-10, c-12 are the two isomers with known physiological importance, including anticarcinogenic, antidiabetic, antilipogenic, and antiatherosclerotic effects. Positive effects of CLA on immune function and bone modeling have also been reported. In spite of the compelling findings in tissue cultures and experimental animal models, its effect, dose, and mechanism of action vis-à-vis specific isomers remains speculative. Results obtained from animal models are inconclusive and conflicting at times in humans, where the research data is limited. It appears that there is a long way to go before CLA could be accepted unequivocally as having definite effects in any or all of these physiological states and how such effects actually occur in humans. The objective of this review is to critically examine the available literature on potential health benefits of CLA observed in cell culture, animal models, and human subjects, wherever possible and to a certain extent the mechanism of action associated with these biological activities.

• Korean Journal of Plant Tissue Culture
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• v.27 no.4
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• pp.245-258
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• 2000

Somatic embryogenesis has become a major tool in the study of plant embryology, as it is possible in culture to manipulate cells of many plant species to produce somatic embryos in a process that is remarkably similar to zygotic embryogenesis. Traditionally, the process has been studied by an examination of the ex vitro factors which influence embryo formation. Later structural, physiological and biochemical approaches have been applied. Host recently, molecular tools are being used. Together, these various approaches are giving valuable information on the process. This article gives an overview of somatic embryogenesis by reviewing information on the morphogenesis, physiology, biochemistry and molecular biology of the process. Topics covered include a brief description of the factors involved in the production of embryogenic cells. Carrot cell suspension is most commonly used, and the development of a high frequency and synchronous system is outlined. At the physiological and biochemical lev-els various topics, including the reactivation of the cell cycle, changes in endogenous growth regulators, amino acid, polyamine, DNA, RNA and protein metabolism, and embryogenic factors in conditioned medium are all discussed. Lastly, recent information on genes and molecular markers of the embryogenic process are outlined. Somatic embryogenesis, the best example of totipotency in plant cells, is not only an important tool in studies in basic biology, but is potentially of equal significance in the micropropagation of economically important plants.

• Journal of Plant Biotechnology
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• v.8 no.1
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• pp.21-25
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• 2006

Phragmites australis (reed) has received much attention as being one of the principle emergent aquatic plants for treating industrial and civil wastewater. Plant regeneration via plant tissue culture in p. australis was investigated. Three types of callus were identified from seeds on N6 medium plus 4.5 UM 2,4-dichlorophenoxyacetic acid (2,4-D). Yellow compact type showed the best redifferentiation, whereas white compact type and yellow friable were not competent to differentiate into plane. Solid medium culture was better than liquid suspension culture for enhancing callus growth when N6 medium supplemented with 4.5 ${\mu}M$ 2,4-D was used. Phytagel, as a gelling agent, was superior to agar in plant regeneration on N6 medium, supplemented with 9.4 ${\mu}M$ kinetin and 0.54 ${\mu}M$ $\alpha$-naphthaleneacetic acid (NAA). Transfer of the plantlets regenerated from kinetin and NAA-supplemented N6 medium to growth regulator-free MS medium enhanced the further development of the plantlets. Plantlets on subsequently grown to maturity when tansferred to potting soil. The regenerated plants exhibited morphologically normal. The system for plant regeneration of P. australis enables to propagate elite lines on a large scale for water purification in the ecosystem