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The Canola Microspore-Derived Embryo as a Model System to Study Developmental Processes in Plants
Yeung, Edward C. 한국식물학회 2002 Journal of Plant Biology Vol.45 No.3
The ability of microspores to undergo embryo development after a successful induction treatment provides a unique experimental system to study a variety of developmental processes in plants. Recent published results focus on the cellular and molecular aspects of the early induction process. In this review, besides summarizing the current findings, the advantages of using the MDE system to study other aspects of embryo development are emphasized. The continual improvement of culturing procedures, media components, and molecular methods guarantees exciting new findings in the near future.
Somatic Embryogenesis - Apical Meristems and Embryo Conversion
Yeung, Edward C.,Stasolla, Claudio The Korean Society of Plant Biotechnology 2000 식물생명공학회지 Vol.27 No.4
A large amount of information is currently available for somatic embryogenesis of plants. However, one common problem related to somatic embryos is that the conversion rate can be low for some species. Apical meristems are responsible for post-embryonic growth of the embryo. The low percentage observed is most likely a result of poor apical meristem development or defects in the meristem organization during somatic embryogenesis. In flowering plants, apical meristems are well developed by the late heart stage of zygotic embryo development. In conifers, such as white spruce, apical meristems are formed at the pre-cotyledon stage. Thus, apical meristem development occurs very early, prior to the maturation stage of embryo development. Once formed, meristems are stably determined. In the somatic embryo, as exemplified by white spruce, since embryo development is not synchronous, tissue differentiation including apical meristem formation occurs throughout the“maturation”stage. Different apical meristem organizations can be found among different individuals within a population. In contrast to their zygotic counterparts, the apical meristems appear not to be stably determined as their organization, as the shoot apical meristem especially, can be easily modified or disrupted. Precocious germination seldom results in functional plantlets. All these observations suggest that the conditions for somatic embryo maturation have not been optimized or are not suitable for meristem formation and development. The following strategies could improve meristem development and hence conversion: 1. Simulate in ouuio conditions to promote meristem development prior to the“maturation”treatment.2. Prevent deterioration of apical meristem organization during somatic embryo maturation.3. Promote further meristem development during embryo germination.
Park, So-Young,Yeung, Edward C.,Paek, Kee-Yoeup The Korean Society of Plant Biotechnology 2010 Plant biotechnology reports Vol.4 No.4
Endoreduplication is a developmental process that is unique to plants and occurs in all plants. The present study aimed to assess endoreduplication in various explant tissues and regenerated somatic embryos of Doritaenopsis. We further investigated the effects of light quality on endoreduplication and somatic embryo proliferation. To this end, we studied endoreduplication in leaves and root tips from regenerated plantlets and somatic embryos and in developing somatic embryos under 4 types of lighting conditions: red light, red + far-red light, red + blue light, and white light. We found that the degree of endoreduplication varied in different explants, and that the choice of explants used also influenced the ploidy levels of the newly regenerated somatic embryos. The DNA content of the leaf (2C-8C) was less than that of the root tip (2C-16C) and somatic embryo (2C-64C). In terms of light quality, the combination of red and far-red light produced the highest number of somatic embryos, while maintaining a low degree of endoreduplication. The data obtained indicate that this light combination stimulates somatic embryogenesis in Doritaenopsis and may exert some control on endoreduplication during cell division. These findings can be applied to achieve a reduction in somaclonal variations for the purpose of mass proliferation and genetic improvement.
Kim, Yun-Soo,Yeung, Edward C,Hahn, Eun-Joo,Paek, Kee-Yoeup Kluwer Academic Publishers 2007 Biotechnology letters Vol.29 No.11
<P>Indole-3-butyric acid at 25 microM with methyl jasmonate (MJ) at 100 microM in Panax ginseng synergistically stimulated both root growth and ginsenoside accumulation compared with 100 microM MJ alone. Productivity of ginsenoside was 10 mg l(-1) d(-1) compared to 7.3 mg l(-1) d(-1) with MJ elicitation alone.</P>
Kang, Seong Ho,Lee, Seungah,Yeung, Edward S. WILEY-VCH Verlag 2006 Electrophoresis Vol.27 No.21
<P>A transmitted-light optical microscope using differential interference contrast (DIC) was employed to follow the real-time dynamics of different kb-sized single native dsDNA molecules without fluorescent-dye labeling. In a PDMS/glass microchip, the electrophoretic migration velocities of large dsDNA molecules are lower than small dsDNA molecules in a running buffer of 0.25% v/v nonionic polymeric surfactant C<SUB>16</SUB>E<SUB>6</SUB> (n-alkyl polyoxyethylene ether) in 100 mM N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid (TES) buffer because the C<SUB>16</SUB>E<SUB>6</SUB> behaved as a dynamic polymer. However, the order of migration reversed in 50 mM Gly–Gly buffer. The radial positions of individual DNA molecules (i.e., center or walls of the microchip) did not change the migration order. The atypical migration order correlated well with the results in CE. The alignment of the deformable molecules due to viscous drag is likely responsible for these observations.</P>
Mining of Laticifer Specific Promoter in Lettuce
Moonhyuk KWON,Elysabeth K BARNES,Connor HODGINS,Edward YEUNG,Yang QU,Seon-Won KIM,Dae-Kyun RO 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
Lettuce (Lactuca sativa) is widely used as a model plant due to advantages such as early flowering, easy transfection, tissue culture, and regeneration. Lettuce laticifers forming a pipe-like structure along the vasculature, and the cytoplasmic content of laticifers is latex. In lettuce latex, terpenoids (natural rubber and sesquiterpene lactone) is synthesized and accumulated as major metabolites. For the heterologous terpenoids production, the lettuce laticifer is suitable tissue because of the enriched terpenoids precursors. However, the lettuce laticifer-specific promoter has not been characterized yet. Here, we identified the promoter of cis-prenyltransferase isoform 3 (LsCPT3) and CPT-binding protein isoform 2 (LsCBP2), the essential genes in natural rubber biosynthesis. From β-glucuronidase (GUS) staining and histochemical sectioning of GUS-stained stem, we proved that the LsCPT3 and LsCBP2 promoter enabled to drive GUS expressions exclusively in laticifers. The LsCBP2 promoter was about 400 folds stronger than the LsCPT3 promoter in laticifers. The LsCBP2 promoter is useful for the latex cell engineering in lettuce.
Grace G.L. Yue,Sau-Wan Cheng,Hua Yu,Zi-Sheng Xu,Julia K.M. Lee,Po-Ming Hon,Mavis Y.H. Lee,Edward J. Kennelly,Gary Deng,Simon K. Yeung,Barrie R. Cassileth,Kwok-Pui Fung,Ping-Chung Leung,Clara B.S. Lau 한국식품영양과학회 2012 Journal of medicinal food Vol.15 No.3
The rhizome of Curcuma longa (turmeric) is often used in Asia as a spice and as a medicine. Its most wellstudied component, curcumin, has been shown to exhibit poor bioavailability in animal studies and clinical trials. We hypothesized that the presence of lipophilic components (e.g., turmerones) in turmeric extract would affect the absorption of curcumin. The effects of turmerones on curcumin transport were evaluated in human intestinal epithelial Caco-2 cells. The roles of turmerones on P-glycoprotein (P-gp) activities and mRNA expression were also evaluated. Results showed that in the presence of a- and aromatic turmerones, the amount of curcumin transported into the Caco-2 cells in 2 hours was significantly increased. a-Turmerone and verapamil (a P-gp inhibitor) significantly inhibited the efflux of rhodamine-123 and digoxin (i.e.,inhibited the activity of P-gp). It is interesting that aromatic turmerone significantly increased the rhodamine-123 efflux and Pgp (MDR1 gene) mRNA expression levels. The effects of a- and aromatic turmerones on curcumin transport as well as P-gp activities were shown here for the first time. The presence of turmerones did affect the absorption of curcumin in vitro. These findings suggest the potential use of turmeric extract (including curcumin and turmerones), rather than curcumin alone, for treating diseases.